Optimal Placement of Temporary Anti-rotation Pin in Tibial Plateau Leveling Osteotomy: A Canine Ex Vivo Study

Optimal Placement of Temporary Anti-rotation Pin in Tibial Plateau Leveling Osteotomy: A Canine Ex Vivo Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Optimal Placement of Temporary Anti-rotation Pin in Tibial Plateau Leveling Osteotomy: A Canine Ex Vivo Study Jeong-Woon Kim, Jung-Moon Kim, Hwi-Yool Kim, Jun-Sik Cho, Keuntae Lee, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6783640/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 31 Oct, 2025 Read the published version in BMC Veterinary Research → Version 1 posted 15 You are reading this latest preprint version Abstract Background Tibial Plateau Leveling Osteotomy (TPLO) is widely accepted for stabilizing the stifle joint in dogs with cranial cruciate ligament disease. However, postoperative tibial tuberosity fractures remain a significant complication, particularly in small-breed dogs. Recent anatomical findings suggest that Sharpey’s fibers(SF) contribute to local structural reinforcement, yet the biomechanical implications of anti-rotation pin positioning relative to these fibers have not been experimentally quantified. Results Eighteen pelvic limbs from nine small-breed canine cadavers (mean body weight 5.98 kg) were assigned to three groups (n = 6) based on anti-rotation pin positioning. Group 1 had the pin inserted perpendicular to the tibial mechanical axis at the level of SF. Group 2 received pin placement 3 mm distal, and Group 3 received placement 6 mm distal and inclined from cranial to caudal. All limbs underwent standardized TPLO, followed by mounting at a standing angle of 135°, and vertical tensile force was applied until failure. Pre- and postoperative tibial plateau angle (TPA) and absolute tibial tuberosity width (ATTW) were measured to ensure anatomical consistency. Group 1 exhibited significantly higher maximum failure loads compared to Groups 2 and 3 (p < 0.017), with no significant difference between the latter two. Fracture configuration differed notably: Group 1 showed complex, comminuted fractures of the distal tibial crest, while Groups 2 and 3 demonstrated simple linear transverse fractures at the mid-crest region. Conclusions Placement of the anti-rotation pin at the level of SF significantly enhances biomechanical resistance of the tibial tuberosity under tensile loading following TPLO. These findings support precise vertical pin positioning as a modifiable surgical variable to reduce fracture risk in small-breed dogs. Further in vivo studies incorporating dynamic loading and breed-specific anatomical variation are warranted to confirm these ex vivo results. small breed dogs tibial plateau leveling osteotomy tibial tuberosity fracture anti-rotation pin Sharpey’s fibers tensile test Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Ⅰ. Background Cranial cruciate ligament disease (CCLD) represents one of the most commonly encountered orthopedic conditions in dogs and constitutes a primary etiology of hindlimb lameness ( 1 , 2 ). The etiology of CCLD remains unclear, though degenerative, biomechanical, genetic, and immune-mediated factors have been implicated ( 3 – 5 ). Various surgical techniques have been developed to address stifle instability caused by CCLD, including intracapsular stabilization, extracapsular stabilization, and radial osteotomy procedures( 2 , 6 – 8 ). Among these, Tibial Plateau Leveling Osteotomy (TPLO) is a widely accepted technique, as it restores stifle stability by neutralizing tibial thrust through modification of the tibial plateau angle during weight-bearing ( 2 , 9 , 10 ). Despite its proven effectiveness, TPLO is associated with complications ranging from 11.4 ~ 34% ( 11 , 12 ), with tibial tuberosity fractures being a significant concern and a critical challenge in surgical outcomes. Fracture of the tibial tuberosity accounts for 0.4-9% ( 12 – 14 ). The complication is clinically significant, often necessitating revision surgery ( 12 ). Proposed risk factors for tibial tuberosity fractures following TPLO include cranialized osteotomy, overcorrection of TPA, poor osteotomy reduction, oversized saw blade use, malpositioned anti-rotation pin, and concurrent bilateral TPLO ( 13 – 15 ). The absolute tibial tuberosity width (ATTW), defined as the narrowest mediolateral width of the tibial tuberosity, measured cranial to the osteotomy and aligned with the patellar ligament(PL) insertion site, is considered a key factor influencing the occurrence of tibial tuberosity fractures following TPLO. Several studies have identified ATTW as an important measure associated with fracture risk ( 13 – 16 ). According to numerous textbooks and peer-reviewed studies, placing the anti-rotation pin at the level of the Sharpey’s Fibers(SF), corresponding to the most cranial part of the tibial tuberosity, is an effective preventive measure against tibial tuberosity fractures following TPLO ( 1 , 12 , 14 , 15 , 17 – 21 ). However, one studies have raised doubts about the efficacy of this approach ( 13 ). Despite of these findings, all available studies are retrospective, and no mechanical testing has quantitatively assessed the relationship between the maximum tensile strength of the quadriceps mechanism, specifically at the tibial tuberosity, and the position of temporary anti-rotation pin insertion. This ex vivo study aimed to evaluate how vertical positioning of the temporary anti-rotation pin, particularly at the level of SF, affects biomechanical stability of the tibial tuberosity during TPLO. Specifically, three different anti-rotation pin insertion techniques were compared, focusing on how the vertical position of the pin relative to SF affects tensile resistance at the tibial tuberosity. It was hypothesized that pinning at the level of SF would result in a significantly higher tensile force to failure compared to more distal pin placements. This biomechanical advantage could potentially reduce the incidence of tibial tuberosity fractures and improve surgical outcomes in clinical settings. Ⅱ. Materials and Methods 2.1. Specimen preparation Pelvic limbs (n=18) harvested from 9 skeletally mature small breed dogs (4-7.9 kg in body weight) euthanized, unrelative to present study (Incheon veterinary medical association, Incheon, Korea). Sample size was based on feasibility, reflecting the number of cadaveric limbs available and constraints of specimen preparation. Standardized craniocaudal and mediolateral radiographs were obtained using a 25 mm calibration marker for measurement calibration. All retrieved limbs were excluded from radiographic imaging if there was any evidence of unclosed physis and pathology affecting femorotibial or femoropatellar joints, or any evidence of orthopedic disease based on tibia or femur deformity, tibial tuberosity, patella, patella ligament, quadriceps mechanism. Only eligible limbs were included, and no samples were excluded after group allocation. The limbs were disarticulated at the hip joint. Then limbs were clipped, labeled, enveloped in gauze moistened with 0.9% saline and subsequently frozen at –70°C. Specimens were allowed to equilibrate at room temperature for 24 hours prior to surgical planning. Specimens were randomly assigned to one of the three groups (n = 6) using an online random list generator(22). Each cadaver contributed two limbs, but each limb was treated independently. 2.2. Osteotomy planning Surgical planning for TPLO was completed preoperatively using vPOP Pro software v3.0.10 (VetSOS Education Ltd.®, Shrewsbury, UK). Mediolateral and craniocaudal radiographs were obtained to assess the osteotomy site and identify any anatomical deformities. The tibial plateau angle (TPA) was assessed in the mediolateral view, following the method described by Slocum and Devine (23,24). The radial osteotomy was centered over the intercondylar tubercles at the geometrically optimal location for TPLO (25). The caudal exit of the osteotomy was planned to be perpendicular to the caudal tibial cortex (16). Tibia width and the absolute tibial tuberosity width (ATTW) was also measured in the mediolateral view using the approach described by Hamilton et al (13,16). Specific measurements denoted as D1, D2, and D3 were taken to determine the osteotomy site using the standard method previously described as follows (26). All limbs were planned that remaining relative tibial tuberosity width was to be around 25% of the craniocaudal tibial width (13,27), in order to minimize the effect of tibia width on tibial tuberosity fracture. If necessary, the center of rotation was adjusted cranially and distally along a 45° trajectory relative to the tibial long axis, following previously described methods, to preserve the overall morphology of the tibial tuberosity (16). 2.3. Surgical procedure All soft tissues were dissected from each limb, preserving the patella, patellar tendon, stifle ligaments, and the distal 4 cm of the quadriceps musculature. A proximal radial osteotomy was performed according to the original technique described by Slocum (10) with a oscillating saw (Zaguar, IMEDICOM®, Gunpo, Gyeonggi-do, Republic of Korea) and 12 or 15 mm TPLO blade (IMEDICOM) were used. Following completion of the tibial plateau osteotomy, the proximal segment was rotated. 2.3.1. Group 1 : Anti-rotational pin at SF A 1.1 mm Kirchner wire was placed in perpendicular to tibial mechanical axis, adjacent to the patellar tendon attachment line (SF) at the most cranial point of tibial tuberosity (Figure 1A) until it engaged the caudal tibial cortex (11,28). 2.3.2. Group 2 : Anti-rotational pin 3mm distal to SF A 1.1 mm Kirchner wire was placed in perpendicular to tibial mechanical axis, 3 mm distal to the patellar tendon attachment line (Figure 1B) until it engaged the caudal tibial cortex. 2.3.3. Group 3 : Anti-rotational pin 6 mm distal to SF A 1.1-mm Kirschner wire was inserted in an inclined cranial-to-caudal direction (Figure 1C), entering the tibial crest 6 mm distal to the patellar tendon attachment line. The wire was advanced until it engaged the caudal tibial cortex, following a technique similar to that described by (29). After the temporary reduction of proximal tibial segment, 2.0 mm 6-hole conventional TPLO plate (Jeil TPLO Plates; Jeil Medical Corp.®, Seoul, Republic of Korea) was stabilized, and the Kirschner wire used for temporary fixation was removed prior to compression and final stabilization with screws. All subsequent procedures were performed by a single surgeon (J.W.K) based on earlier surgical planning. The TPLO surgery aimed to achieve a postoperative TPA of 5° (27,30). The surgeon selected either 12 or 15 mm TPLO saw. Pin placement was visually aligned relative to the tibial mechanical axis during surgery. In Group 1 and 2, the pin was intended to be placed perpendicular to the axis, and in Group 3, at an inclined cranial-to-caudal direction. However, no postoperative radiographic or angular measurements were performed to objectively verify the pin orientations. 2.4. Postoperative radiography Immediate postoperative radiographs (Figure 2) were obtained for every limb. On these images the ATTW, TPA, and rotation length were measured. A limb was accepted for further analysis only if it met all three radiographic criteria: (1) a postoperative TPA of 0–14° (30,31); (2) no discernible osteotomy gap; and (3) secure bicortical screw purchase. Specimens that failed to satisfy any one of these thresholds were discarded and replaced with newly prepared limbs. All measurements were obtained in triplicate, in a single session, by the same investigator (J.W.K.). 2.5. Biomechanical evaluation For biomechanical testing, the hock and stifle joints were disarticulated, retaining only the tibia with the TPLO construct, the patella, PL, and the distal 4 cm of the quadriceps muscle. Each specimen was secured to a wooden board angled at 135° to the tibial axis to simulate the mid-stance phase of gait (16,32,33). A 1.8 mm Steinmann pin was inserted through the tibial shaft into the board for fixation, and three additional 2.0 mm cortical screws were placed in the proximal and distal tibia to counteract rotational forces . Incremental tensile force was then applied to the quadriceps muscle via a custom gripping jig (Figure 3). Vertical distraction was performed at a constant displacement rate of 10 mm/min using a mechanical testing machine (Instron 5585; Instron Corp.®, Norwood, MA, USA) until tibial tuberosity failure occurred. Failure was defined as the first abrupt drop in the load-displacement curve. The primary outcome measure was the maximum failure load (N) of the tibial tuberosity under vertical tensile force. Radiographs were obtained post-failure to document the fracture configuration and location. Parameters recorded for each specimen included pre-osteotomy tibial width (mm), post-osteotomy ATTW (mm), TPA (°), maximum failure load (N), and mode of failure. 2.6. Statistical analysis All statistical analyses were conducted using SPSS software v.30.0.0.0 (IBM Corp., Armonk, NY, USA). Due to the small sample size in each of the three groups, non-parametric tests were employed. Group comparisons were conducted using the Kruskal–Wallis test, followed by post hoc pairwise analysis using the Mann–Whitney U test with Bonferroni correction. A p-value < 0.017 was considered statistically significant. No blinding was applied in this study. All procedures, including specimen preparation, group allocation, TPLO, and outcome measurement, were jointly conducted by two investigators (J.W.K. and J.M.K.). Ⅲ. Results Eighteen hindlimbs were harvested from nine skeletally mature small-breed canine cadavers between March 2024 and January 2025. The mean body weights were similar across Groups (G1: 6.04 ± 1.19 kg, G2: 5.93 ± 1.08 kg, G3: 5.98 ± 1.37 kg) (Table 1 ), with no statistically significant difference (Kruskal–Wallis, p = 0.975). 3.1. Pre- and Postoperative ATTW and TPA There were no statistically significant differences among the Groups in either ATTW or TPA at both the preoperative (ATTW, p = 0.874; TPA, p = 0.717) or postoperative (ATTW, p = 0.352; TPA, p = 0.874) time points, as determined by Kruskal–Wallis testing. The mean postoperative ATTW values were 5.40 ± 0.40 mm in Group 1, 5.62 ± 0.96 mm in Group 2, and 5.93 ± 0.35 mm in Group 3, while the mean postoperative TPA values were 4.33 ± 2.16°, 4.70 ± 3.28°, and 4.48 ± 2.52°, respectively (Table 1 ). Table 1 Pre- and postoperative tibial plateau angle (TPA), absolute tibial tuberosity width (ATTW), and body weight Parameter Group 1 Group 2 Group 3 p value Preoperative TPA (°) 27.67 ± 4.22 29.17 ± 3.92 27.58 ± 3.64 0.717 Postoperative TPA (°) 4.33 ± 2.16 4.70 ± 3.28 4.48 ± 2.52 0.874 Preoperative ATTW (mm) 5.68 ± 0.73 5.63 ± 0.92 5.90 ± 0.77 0.856 Postoperative ATTW (mm) 5.40 ± 0.40 5.62 ± 0.96 5.93 ± 0.35 0.352 Body Weight (kg) 6.04 ± 1.19 5.93 ± 1.08 5.98 ± 1.37 0.972 Values are presented as mean ± standard deviation. No statistically significant differences were detected among Groups at any measurement time point, based on Kruskal–Wallis analysis (p > 0.05). Group 1: Pin at SF; Group 2: Pin 3 mm distal to SF; Group 3: Pin 6 mm distal to SF with an inclined cranial-to-caudal direction. 3.2. Maximum Failure Load Maximum failure load differed significantly among the three groups ( p = 0.0086). Group 1 (326.27 ± 62.66 N; 95% CI: 260.29–391.97) showed significantly greater tensile strength than Group 2 (194.05 ± 61.26 N; 95% CI: 129.73–258.31; p = 0.0087) and Group 3 (213.25 ± 58.43 N; 95% CI: 151.93–274.57; p = 0.0152) (Figure. 4). No significant difference was observed between Group 2 and Group 3 ( p = 0.5887). 3.3. Types of Failure Failure configurations differed among Groups, exhibiting distinct patterns depending on pin placement (Table 2 ). Group 1 exhibited a mix of comminuted distal tibial crest fractures (n = 3) (Fig. 5 A) and transverse mid-tibial crest fractures, with the latter showing irregular fracture lines (n = 3) (Fig. 5 B). In contrast, all specimens in Group 2 (n = 6) demonstrated transverse mid-tibial crest fractures with relatively linear configurations (Fig. 5 C). Group 3 consistently showed distal tibial crest transverse fractures (n = 6) (Fig. 5 D), with fracture lines similarly linear to those in Group 2. Table 2 Failure modes observed in each group following tensile testing Group Types of Failure Group 1 Comminuted distal tibial crest fracture(n = 3) Transverse mid-tibial crest fracture(n = 3) Group 2 Mid-tibial crest fractures with linear configurations (n = 6) Group 3 Mid-tibial crest fractures with linear configurations (n = 6) Group 1: Pin placed at SF; Group 2: Pin placed 3 mm distal to SF; Group 3: Pin placed 6 mm distal to SF with an inclined cranial-to-caudal direction. Ⅳ. Discussion These results of this study demonstrate that the position of the anti-rotation pin has a decisive influence on the tensile strength of the tibial tuberosity following TPLO (Fig. 4 ). The pin placed at the most cranial location demonstrated significantly higher resistance to failure, confirming the mechanical advantage of engaging the structurally reinforced region near SF. These results highlight pin location as a controllable factor in surgical planning, with the potential to reduce tibial tuberosity fracture by minimizing stress concentrations in the tibial crest. Post operative tibial tuberosity fracture in TPLO has been associated in several reports, with a set of modifiable risk factors ( 12 , 14 – 18 ), notably including a shallow residual tibial tuberosity width, excessive TPA correction, greater body weight loading, and malposition of the temporary anti rotation pin. In the present study, radiographic evaluation confirmed that pre and post-operative TPA, ATTW, and body did not differ significantly among the three groups, indicating comparable baseline anatomy and surgical correction (Table 1 ). With these factors statistically equivalent, the observed differences in maximum tensile failure load can be attributed chiefly to the location of the anti-rotation pin relative to SF. The superior biomechanical performance observed in Group 1 can be attributed to two complementary anatomical factors: first, the robust anchoring provided by SF at the cranial tibial tuberosity, and second, the inherently greater bone stock available at this anatomical site compared to distal locations. SF are specialized collagenous structures that anchor muscles, tendons, ligaments, and periosteum to underlying bone, playing a critical role in biomechanical stability by effectively distributing muscular and ligamentous forces across bone interfaces ( 1 , 34 ). According to recent studies in human medicine, these fibers are believed to participate in bone remodeling and reparative responses, suggesting a broader biological relevance in maintaining musculoskeletal stability ( 35 , 36 ). Anatomically, SF are most commonly localized in anatomical regions exposed to substantial tensile forces, such as alveolar bone sockets, cranial sutures, and, in particular, entheses where tendons or ligaments integrate with bone tissue ( 1 ). In human orthopedic surgery, increasing awareness of the biomechanical significance of SF has prompted a growing emphasis on preserving the structural integrity of tendon-to-bone interfaces, particularly through techniques aimed at minimizing iatrogenic disruption ( 35 ). In veterinary medicine, specifically during TPLO, clinical observations have suggested a greater predisposition to tibial tuberosity fractures when the temporary pin were placed distal to SF insertion ( 1 , 15 , 17 , 21 ). This finding suggests that placing the pin distal to SF may impair local biomechanical integrity and increase susceptibility to avulsion fractures at the tibial tuberosity. Several studies have highlighted the crucial role of tibial tuberosity morphology in fracture prevention and noted considerable individual variation in the location of the PL insertion ( 14 , 16 , 29 , 37 , 38 ). According to Mehrkens et al ., an evaluation of the tibial tuberosity’s shape in relation to the PL insertion revealed that tuberosities exhibiting their narrowest point distal to the PL were significantly more susceptible to fractures compared with those that tapered above or at the PL insertion. These findings emphasize the importance of both bone stock and tuberosity geometry in preventing postoperative complications, particularly during TPLO. In the present study, distal pin placement where the tibial tuberosity is inherently thinner, was associated with a marked reduction in maximum failure load, further confirming that limited bone stock substantially compromises mechanical integrity (Fig. 6 ). By contrast, pinning near to SF, which coincides with greater bone stock and robust tendon-bone attachments, appears to capitalize on the enhanced structural support (Fig. 6 ). These observations suggest that pinning near SF, characterized by greater bone stock and stronger tendon-bone anchorage, may improve mechanical stability and reduce the risk of tibial tuberosity fractures. If pin placement is planned distal to the SF whether for supplementary stabilization or due to inadvertent placement, maintaining the pin as a permanent fixture rather than temporary fixation to reduce the risk of creating a stress riser at the insertion site is suggested. Notably, the retrospective clinical study found no significant association between the vertical position of the anti-rotation pin and the incidence of tibial tuberosity fractures ( 13 ). This discrepancy may be partly explained by differences in patient population, as that study primarily involved medium- to large-breed dogs. In such breeds, the tibial crest typically provides more robust bone stock, potentially mitigating the mechanical consequences of distal pin placement. In contrast, the current study exclusively involved small-breed dogs, in which limited bone stock in the tibial crest, has been identified as a significant surgical challenge ( 39 ). These anatomical differences may help explain the inconsistent findings, though further validation is needed. The similar failure loads between Group 2 and 3 observed in present study may be attributed to the fact that both pin placements remained within the tibial crest, a region where bone stock is relatively uniform from its mid to distal extent, resulting in minimal variation in biomechanical resistance. It is plausible that positioning the pin distal to the tibial crest, where bone stock markedly is increased, might yield different mechanical outcomes. Further research examining the biomechanical consequences of pin placements distal to the tibial crest is needed. Fracture configurations observed in this study under tensile loading revealed distinct patterns based on the pin's vertical positioning relative to SF (Table 2 , Fig. 5 ). Specimens in Group 1, with the pin placed directly at SF, exhibited either comminuted distal tibial crest fractures or transverse mid-tibial crest fractures with irregular fracture lines. These diverse fracture patterns suggest a robust and uneven load distribution across the tibial tuberosity, reflecting the strong structural support provided by the abundant SF and substantial bone stock in the most cranial aspect of tibial tuberosity. Conversely, all specimens in Group 2 and 3 consistently demonstrated transverse mid-tibial crest fractures with relatively linear fracture configurations. Such uniform failure patterns indicate a predictable but mechanically weaker region, particularly when the pin was positioned more distally, where bone stock is reduced, and SF density is diminished. These observations reinforce the biomechanical importance of optimal pin placement relative to the SF insertion, highlighting the need for precise surgical planning to mitigate fracture risks during TPLO procedures in clinical settings. Indeed, similar mid-crest fractures have been commonly documented in retrospective clinical studies where the anti-rotation pin was positioned more distally ( 14 , 17 , 18 ). This consistency between experimental and clinical findings further underscores the vulnerability associated with distal pin placement. In relation to the forces acting through the stifle joint during canine gait, a previous study utilizing three-dimensional biomechanical modeling indicated that quadriceps muscle force during a slow walk can vary substantially depending on the stifle flexion angle, ranging from approximately 16.5% up to 94.8% of the dog's body weight ( 32 ). Typical stifle flexion angles during mid-stance are generally reported between 120° and 140°, consistent with previously documented canine gait mechanics ( 33 ). Given this physiological context and considering the body weight range of the small-breed dogs in present study (4.0–7.9 kg; approximately 39–78 N), it is reasonable to estimate that the quadriceps force exerted on the tibial tuberosity during slow walking may fall within a comparable proportion of the vertical ground reaction force, likely approaching 95%. Accordingly, the muscular load would be expected to range between approximately 37 and 74 N, although interindividual variability and gait asymmetry could influence the actual force transmission. These estimated forces are considerably lower than the lowest maximum tensile failure load measured in current study (approximately 194 N), suggesting that immediate structural failure is unlikely during normal walking activities in clinical situations. Nevertheless, it must be recognized that Shahar’s model provides only an approximation of quadriceps force during slow walking and does not account for higher-intensity activities such as trotting, jumping, or stair climbing, all of which likely impose substantially greater loads on the quadriceps mechanism. Further biomechanical investigations incorporating dynamic loading conditions and a broader range of functional activities are warranted to better elucidate the mechanical demands placed on the tibial tuberosity in vivo. Despite the biomechanical insights provided by this study, several experimental limitations must be acknowledged. The exclusive use of small-breed canine limbs limits the applicability of these results to larger breeds with different anatomical characteristics. Moreover, the cadaveric nature of this investigation precluded physiological responses such as bone remodeling and SF development, which are critical to long-term fixation stability. Histologic evidence from in vivo studies indicates that SF begin to form around eight weeks postoperatively in dogs ( 40 ). Their morphology is influenced by biological variables including age, hormonal status, and bone disease, emphasizing the need for complementary in vivo research to elucidate these interactions ( 34 ). Static axial loading failed to replicate cyclic mechanical stress experienced during ambulation, which may critically influence tibial tuberosity stress over time. Given that clinical fractures often occur between two and six weeks postoperatively( 13 , 21 ), future studies incorporating dynamic loading models are warranted to enhance clinical relevance. Pin placement was visually aligned intraoperatively, but no radiographic or angular measurements were conducted to confirm precise orientation relative to the tibial axis, limiting repeatability. Additionally, removal of periarticular soft tissues and absence of donor histories prevented assessment of structural stabilizers and underlying pathology, further limiting clinical extrapolation. Nevertheless, the findings of this study clearly emphasize that precise positioning of the temporary anti-rotation pin near SF significantly enhances biomechanical stability, potentially reducing the risk of postoperative tibial tuberosity fractures in small-breed dogs undergoing TPLO. Further in vivo studies incorporating dynamic loading conditions, breed-specific anatomical variations, and dogs of various sizes are required to overcome the inherent limitations of this ex vivo investigation and fully validate these biomechanical outcomes. Ⅴ. Conclusion This study demonstrates that positioning the anti-rotation pin at SF in tibial tuberosity significantly enhances the biomechanical strength and reduces fracture risk following TPLO in small-breed dogs. Distal pin placement compromises structural integrity due to limited bone stock, increasing fracture susceptibility. Clinically, optimal pin placement at SF is recommended to minimize complications. Abbreviations SF : Sharpey’s Fibers CCLD: Cranial Cruciate Ligament Disease TPLO: Tibial Plateau Leveling Osteotomy ATTW: Apical Tibial Tuberosity Width TPA: Tibial Plateau Angle PL: Patellar Ligament SD: Standard Deviation CI: Confidence Interval BW: Body Weight N: Newton Declarations Ethics approval and consent to participate Not applicable. This study used canine cadaveric limbs sourced from animals euthanized for reasons unrelated to this research. Consent for publication Not applicable. Availability of data and materials All data generated or analyzed during this study are included in this published article and its supplementary information files. Competing interests The authors declare that they have no competing interests. Funding This study was supported by the Graduate School Research Program of Konkuk University (Seoul, Republic of Korea). The funding body had no role in study design, data collection, analysis, interpretation, or manuscript preparation. Authors' contributions J.W. Kim and J.M. Kim contributed equally as co-first authors. They jointly performed all experimental procedures, including cadaveric limb preparation, TPLO surgery, data collection, and manuscript writing. J.S. Cho conducted statistical analyses, created all figures, and assisted in experimental design and execution. K. Lee, J. Jo, and J.H. Kim contributed to cadaveric preparation and participated in all stages of the experiments. S.K. Jang and S.Y. Lee supported specimen handling and procedural assistance as research veterinarians. H.Y. Kim supervised the entire study, including experimental design and scientific oversight, as the corresponding author. All authors reviewed and approved the final manuscript. Acknowledgements The authors thank the Clinical Research Laboratory and the Department of Veterinary Surgery at Konkuk University for providing technical assistance and institutional resources during this study. References Johnston SA, Tobias KM, editors. 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Geometric analysis evaluating the effect of tibial plateau leveling osteotomy position on postoperative tibial plateau slope. Vet Comp Orthop Traumatol. 2004 Jan;17(01):30–4. Jeong E, Jeon Y, Kim T, Lee D, Roh Y. Assessing the Effectiveness of Modified Tibial Plateau Leveling Osteotomy Plates for Treating Cranial Cruciate Ligament Rupture and Medial Patellar Luxation in Small-Breed Dogs. Animals. 2024 Jun 30;14(13):1937. Tan CJ, Bergh MS, Schembri MA, Johnson KA. Accuracy of Tibial Osteotomy Placement Using 2 Different Tibial Plateau Leveling Osteotomy Jigs. Veterinary Surgery. 2014 Jul;43(5):525–33. Jay MR, Mattoon JS, Gilbert PJ, Tanaka TT, Beaty BL. Radiographic evaluation of patellar ligament length after tibial plateau leveling osteotomy in dogs. ajvr. 2019 Jun;80(6):607–12. Talaat MB, Kowaleski MP, Boudrieau RJ. Combination Tibial Plateau Leveling Osteotomy and Cranial Closing Wedge Osteotomy of the Tibia for the Treatment of Cranial Cruciate Ligament‐Deficient Stifles with Excessive Tibial Plateau Angle. Veterinary Surgery. 2006 Dec;35(8):729–39. Volz F, Eberle D, Klever J, Zablotski Y, Kornmayer M. Effect of tibial plateau angle < 5° on ground reaction forces in dogs treated with tibial plateau leveling osteotomy for cranial cruciate ligament rupture up to 6 months postoperatively. The Veterinary Journal. 2024 Jun 1;305:106126. Robinson DA, Mason DR, Evans R, Conzemius MG. The Effect of Tibial Plateau Angle on Ground Reaction Forces 4–17 Months After Tibial Plateau Leveling Osteotomy in Labrador Retrievers. Veterinary Surgery. 2006 Apr;35(3):294–9. Shahar R, Banks-Sills L. Biomechanical Analysis of the Canine Hind Limb: Calculation of Forces During Three-legged Stance. The Veterinary Journal. 2002 May;163(3):240–50. Shahar R, Banks-Sills L. A quasi-static three-dimensional, mathematical, three-body segment model of the canine knee. Journal of Biomechanics. 2004;37(12):1849–59. Aaron JE. Periosteal SF: a novel bone matrix regulatory system? Front Endocrin [Internet]. 2012 [cited 2025 Jan 24];3. Available from: http://journal.frontiersin.org/article/10.3389/fendo.2012.00098/abstract Lui P, Zhang P, Chan K, Qin L. Biology and augmentation of tendon-bone insertion repair. J Orthop Surg Res. 2010;5(1):59. Tsarouhas A, Hantes ME. Bone-Tendon and Bone-Ligament Interface. In: Karachalios T, editor. Bone-Implant Interface in Orthopedic Surgery [Internet]. London: Springer London; 2014 [cited 2025 Jan 24]. p. 307–25. Available from: https://link.springer.com/10.1007/978-1-4471-5409-9_21 Duerr FM, Duncan CG, Savicky RS, Park RD, Egger EL, Palmer RH. Comparison of Surgical Treatment Options for Cranial Cruciate Ligament Disease in Large‐Breed Dogs with Excessive Tibial Plateau Angle. Veterinary Surgery. 2008 Jan;37(1):49–62. Fujino H, Honnami M, Mochizuki M. Preoperative planning for tibial plateau leveling osteotomy based on proximal tibial width. J Vet Med Sci. 2020;82(5):661–7. Hackett M, St Germaine L, Carno MA, Hoffmann D. Comparison of Outcome and Complications in Dogs Weighing Less Than 12 kg Undergoing Miniature Tibial Tuberosity Transposition and Advancement versus Extracapsular Stabilization with Tibial Tuberosity Transposition for Cranial Cruciate Ligament Disease with Concomitant Medial Patellar Luxation. Vet Comp Orthop Traumatol. 2021 Mar;34(02):099–107. Rodeo SA, Arnoczky SP, Torzilli PA, Hidaka C, Warren RF. Tendon-healing in a bone tunnel. A biomechanical and histological study in the dog.: The Journal of Bone & Joint Surgery. 1993 Dec;75(12):1795–803. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 31 Oct, 2025 Read the published version in BMC Veterinary Research → Version 1 posted Editorial decision: Revision requested 04 Jul, 2025 Reviewers agreed at journal 03 Jul, 2025 Reviews received at journal 03 Jul, 2025 Reviews received at journal 27 Jun, 2025 Reviewers agreed at journal 27 Jun, 2025 Reviewers agreed at journal 27 Jun, 2025 Reviews received at journal 27 Jun, 2025 Reviewers agreed at journal 25 Jun, 2025 Reviewers agreed at journal 25 Jun, 2025 Reviewers agreed at journal 25 Jun, 2025 Reviewers invited by journal 25 Jun, 2025 Editor invited by journal 24 Jun, 2025 Editor assigned by journal 02 Jun, 2025 Submission checks completed at journal 02 Jun, 2025 First submitted to journal 30 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6783640","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":477610133,"identity":"6c6e09cb-30af-433c-a116-87a33fa4230b","order_by":0,"name":"Jeong-Woon Kim","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8klEQVRIiWNgGAWjYJACAzjrAxCzsRPUwIzQwjgDpIWZCC0IJg+aAHZHHe8/UPCh4o7dhuPNxx7b/Nomz8fMwPjhYw4eLWcOMxjOOPMsecOZY+nGuX23DduYGZglZ27DrUVyRjKDMW/b4WSzGzlm0rk9txmBWtiYefFpmf+YwfgvTItlz217glr4JZgZjBnbDtuBtTD8uJ1IWAtPsoFhz5nDCfZnjqVJ9jbcTm5jZmzG6xc29oPPDH5UHLaXbG8+JvHjz23b+e3NBz98xKMFpAsUlYkNICZjG5hswKseCJgfAAl7CPsPIcWjYBSMglEwEgEAVFBQgOtYfQ4AAAAASUVORK5CYII=","orcid":"","institution":"Konkuk University","correspondingAuthor":true,"prefix":"","firstName":"Jeong-Woon","middleName":"","lastName":"Kim","suffix":""},{"id":477610134,"identity":"edb983be-0ccf-45b7-ad44-bbe8e0a9fbb4","order_by":1,"name":"Jung-Moon Kim","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Jung-Moon","middleName":"","lastName":"Kim","suffix":""},{"id":477610135,"identity":"bc6662e6-00a9-4f79-b4ba-95dfac136b3c","order_by":2,"name":"Hwi-Yool Kim","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Hwi-Yool","middleName":"","lastName":"Kim","suffix":""},{"id":477610136,"identity":"2bb408c3-9260-4dc8-97cf-971949c21867","order_by":3,"name":"Jun-Sik Cho","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Jun-Sik","middleName":"","lastName":"Cho","suffix":""},{"id":477610137,"identity":"9725d560-0d63-457b-ace8-12dfb49c8d47","order_by":4,"name":"Keuntae Lee","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Keuntae","middleName":"","lastName":"Lee","suffix":""},{"id":477610138,"identity":"cb4e054e-bd6e-4a0e-945e-89f2f1685d05","order_by":5,"name":"Junsuk Jo","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Junsuk","middleName":"","lastName":"Jo","suffix":""},{"id":477610139,"identity":"7c34ba7b-6a1f-481a-9177-8fadcbb393a2","order_by":6,"name":"Jung-Hyun Kim","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Jung-Hyun","middleName":"","lastName":"Kim","suffix":""},{"id":477610140,"identity":"ba0c98dc-8bb3-4684-b871-83d8b88f6f35","order_by":7,"name":"Sangyul Lee","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Sangyul","middleName":"","lastName":"Lee","suffix":""},{"id":477610141,"identity":"d1f0474d-87ec-4ca8-a9bd-3eaff3149288","order_by":8,"name":"Sang-Kun Jang","email":"","orcid":"","institution":"Konkuk University","correspondingAuthor":false,"prefix":"","firstName":"Sang-Kun","middleName":"","lastName":"Jang","suffix":""}],"badges":[],"createdAt":"2025-05-30 10:08:26","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6783640/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6783640/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12917-025-05065-4","type":"published","date":"2025-10-31T15:57:46+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":85742914,"identity":"b24c0c16-a071-4041-9542-825ab4377d30","added_by":"auto","created_at":"2025-07-01 09:08:33","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":308790,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic illustrations of anti-rotational pin placement in three groups. (A) Group 1: pin placed adjacent to SF; (B) Group 2: pin placed 3 mm distal to SF; (C) Group 3: pin placed 6 mm distal with an inclined cranial-to-caudal trajectory\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6783640/v1/2dedbcbcaafea071d2a5e76b.png"},{"id":85742910,"identity":"22fe6241-17ef-427c-b910-c96677d73ceb","added_by":"auto","created_at":"2025-07-01 09:08:33","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":275629,"visible":true,"origin":"","legend":"\u003cp\u003eImmediate postoperative mediolateral radiographs of the stifle following TPLO and anti-rotational pin placement. Radiographs represent (A) Group 1, (B) Group 2, and (C) Group 3. Radiographic measurements of ATTW, TPA, and rotation length were performed to confirm eligibility for biomechanical testing. The temporary Kirschner wire used during surgery was removed prior to final plate fixation and are not visible on the radiographs.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6783640/v1/65e1f2aa466bd6f8e183dbbd.png"},{"id":85742933,"identity":"1a636c1c-b4a4-407b-aaca-b5430dc1857a","added_by":"auto","created_at":"2025-07-01 09:08:34","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":481168,"visible":true,"origin":"","legend":"\u003cp\u003eA photograph of axial tensile testing model. Each specimen was secured at 135° relative to the tibial axis and subjected to vertical distraction (indicated by the arrow) at a constant rate of 10 mm/min until tibial tuberosity failure occurred.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6783640/v1/6ffd57a74edb85a6c08a065f.png"},{"id":85742822,"identity":"52e00764-6048-43b4-b231-5c52ed7648a4","added_by":"auto","created_at":"2025-07-01 09:08:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":35917,"visible":true,"origin":"","legend":"\u003cp\u003eMaximum failure loads under axial tensile force among Groups. Different superscript letters indicate statistically significant differences at \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.017. Group 1: Pin at SF; Group 2: Pin 3 mm distal to SF; Group 3: Pin 6 mm distal to SF with an inclined cranial-to-caudal direction.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6783640/v1/d73f332192de568ba2b0d222.png"},{"id":85742893,"identity":"69c6f00d-1167-4d20-8e95-591a0cd65890","added_by":"auto","created_at":"2025-07-01 09:08:33","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":279990,"visible":true,"origin":"","legend":"\u003cp\u003eMediolateral radiographs of stifles after biomechanical test. (A\u0026amp;B) Two specimens from Group 1 showing distal tibial crest comminuted fracture (A) and transverse mid-tibial crest fracture (B); (C) Specimen from Group 2 with a transverse mid-tibial crest fracture; (D) Specimen from Group 3 with a distal tibial crest transverse fracture.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6783640/v1/8ec6dc26a5f89949a15c48eb.png"},{"id":85742922,"identity":"83724b28-150a-489f-a9f9-0565f46458ee","added_by":"auto","created_at":"2025-07-01 09:08:34","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":301668,"visible":true,"origin":"","legend":"\u003cp\u003eIllustrations of cross-sectional tibial crest anatomy and planned group-specific vertical pin positions. Transverse sections highlight the progressive thinning of bone stock from proximal to distal regions of the tibial crest. Each group represents the expected vertical location of pin insertion as follows: (A) Group 1; (B) Group 2; (C) Group 3. The diagram emphasizes the reduction in bone stock in distal regions, reflecting the observed differences in mechanical strength and fracture configuration\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6783640/v1/795de79d3131c41ad9dbc8c3.png"},{"id":95040441,"identity":"98e0890f-ec16-466f-a6f3-48030bb107b2","added_by":"auto","created_at":"2025-11-03 16:08:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2803379,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6783640/v1/f2fb0144-de6b-4185-9a10-f8d82116dfd5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Optimal Placement of Temporary Anti-rotation Pin in Tibial Plateau Leveling Osteotomy: A Canine Ex Vivo Study","fulltext":[{"header":"Ⅰ. Background","content":"\u003cp\u003eCranial cruciate ligament disease (CCLD) represents one of the most commonly encountered orthopedic conditions in dogs and constitutes a primary etiology of hindlimb lameness (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). The etiology of CCLD remains unclear, though degenerative, biomechanical, genetic, and immune-mediated factors have been implicated (\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). Various surgical techniques have been developed to address stifle instability caused by CCLD, including intracapsular stabilization, extracapsular stabilization, and radial osteotomy procedures(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). Among these, Tibial Plateau Leveling Osteotomy (TPLO) is a widely accepted technique, as it restores stifle stability by neutralizing tibial thrust through modification of the tibial plateau angle during weight-bearing (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Despite its proven effectiveness, TPLO is associated with complications ranging from 11.4\u0026thinsp;~\u0026thinsp;34% (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e), with tibial tuberosity fractures being a significant concern and a critical challenge in surgical outcomes.\u003c/p\u003e \u003cp\u003eFracture of the tibial tuberosity accounts for 0.4-9% (\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). The complication is clinically significant, often necessitating revision surgery (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). Proposed risk factors for tibial tuberosity fractures following TPLO include cranialized osteotomy, overcorrection of TPA, poor osteotomy reduction, oversized saw blade use, malpositioned anti-rotation pin, and concurrent bilateral TPLO (\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e). The absolute tibial tuberosity width (ATTW), defined as the narrowest mediolateral width of the tibial tuberosity, measured cranial to the osteotomy and aligned with the patellar ligament(PL) insertion site, is considered a key factor influencing the occurrence of tibial tuberosity fractures following TPLO. Several studies have identified ATTW as an important measure associated with fracture risk (\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAccording to numerous textbooks and peer-reviewed studies, placing the anti-rotation pin at the level of the Sharpey\u0026rsquo;s Fibers(SF), corresponding to the most cranial part of the tibial tuberosity, is an effective preventive measure against tibial tuberosity fractures following TPLO (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan additionalcitationids=\"CR18 CR19 CR20\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). However, one studies have raised doubts about the efficacy of this approach (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). Despite of these findings, all available studies are retrospective, and no mechanical testing has quantitatively assessed the relationship between the maximum tensile strength of the quadriceps mechanism, specifically at the tibial tuberosity, and the position of temporary anti-rotation pin insertion.\u003c/p\u003e \u003cp\u003eThis \u003cem\u003eex vivo\u003c/em\u003e study aimed to evaluate how vertical positioning of the temporary anti-rotation pin, particularly at the level of SF, affects biomechanical stability of the tibial tuberosity during TPLO. Specifically, three different anti-rotation pin insertion techniques were compared, focusing on how the vertical position of the pin relative to SF affects tensile resistance at the tibial tuberosity.\u003c/p\u003e \u003cp\u003eIt was hypothesized that pinning at the level of SF would result in a significantly higher tensile force to failure compared to more distal pin placements. This biomechanical advantage could potentially reduce the incidence of tibial tuberosity fractures and improve surgical outcomes in clinical settings.\u003c/p\u003e"},{"header":"Ⅱ. Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003e2.1. Specimen preparation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePelvic limbs (n=18) harvested from 9 skeletally mature small breed dogs (4-7.9 kg in body weight) euthanized, unrelative to present study (Incheon veterinary medical association, Incheon, Korea). Sample size was based on feasibility, reflecting the number of cadaveric limbs available and constraints of specimen preparation. Standardized craniocaudal and mediolateral radiographs were obtained using a 25 mm calibration marker for measurement calibration. All retrieved limbs were excluded from radiographic imaging if there was any evidence of unclosed physis and pathology affecting femorotibial or femoropatellar joints, or any evidence of orthopedic disease based on tibia or femur deformity, tibial tuberosity, patella, patella ligament, quadriceps mechanism. Only eligible limbs were included, and no samples were excluded after group allocation. The limbs were disarticulated at the hip joint. Then limbs were clipped, labeled, enveloped in gauze moistened with 0.9% saline and subsequently frozen at \u0026ndash;70\u0026deg;C. Specimens were allowed to equilibrate at room temperature for 24 hours prior to surgical planning. Specimens were randomly assigned to one of the three groups (n = 6) using an online random list generator(22). Each cadaver contributed two limbs, but each limb was treated independently. \u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2. Osteotomy planning\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSurgical planning for TPLO was completed preoperatively using vPOP Pro software v3.0.10 (VetSOS Education Ltd.\u0026reg;, Shrewsbury, UK). Mediolateral and craniocaudal radiographs were obtained to assess the osteotomy site and identify any anatomical deformities. The tibial plateau angle (TPA) was assessed in the mediolateral view, following the method described by Slocum and Devine (23,24). The radial osteotomy was centered over the intercondylar tubercles at the geometrically optimal location for TPLO (25). The caudal exit of the osteotomy was planned to be perpendicular to the caudal tibial cortex (16). Tibia width and the absolute tibial tuberosity width (ATTW) was also measured in the mediolateral view using the approach described by Hamilton \u003cem\u003eet al\u0026nbsp;\u003c/em\u003e(13,16). Specific measurements denoted as D1, D2, and D3 were taken to determine the osteotomy site using the standard method previously described as follows (26).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll limbs were planned that remaining relative tibial tuberosity width was to be around 25% of the craniocaudal tibial width\u0026nbsp;(13,27), in order to minimize the effect of tibia width on tibial tuberosity fracture.\u003c/p\u003e\n\u003cp\u003eIf necessary, the center of rotation was adjusted cranially and distally along a 45\u0026deg; trajectory relative to the tibial long axis, following previously described methods, to preserve the overall morphology of the tibial tuberosity (16). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Surgical procedure\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll soft tissues were dissected from each limb, preserving the patella, patellar tendon, stifle ligaments, and the distal 4 cm of the quadriceps musculature. A proximal radial osteotomy was performed according to the original technique described by Slocum (10) with a oscillating saw (Zaguar, IMEDICOM\u0026reg;, Gunpo, Gyeonggi-do, Republic of Korea) and 12 or 15 mm TPLO blade (IMEDICOM) were used. Following completion of the tibial plateau osteotomy, the proximal segment was rotated.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3.1. Group 1 : Anti-rotational pin at SF\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 1.1 mm Kirchner wire was placed in perpendicular to tibial mechanical axis, adjacent to the patellar tendon attachment line (SF) at the most cranial point of tibial tuberosity (Figure 1A) until it engaged the caudal tibial cortex (11,28). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3.2. Group 2 : Anti-rotational pin 3mm distal to SF\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 1.1 mm Kirchner wire was placed in perpendicular to tibial mechanical axis, 3 mm distal to the patellar tendon attachment line (Figure 1B) until it engaged the caudal tibial cortex.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3.3. Group 3 : Anti-rotational pin 6 mm distal to SF\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA 1.1-mm Kirschner wire was inserted in an inclined cranial-to-caudal direction (Figure 1C), entering the tibial crest 6 mm distal to the patellar tendon attachment line. The wire was advanced until it engaged the caudal tibial cortex, following a technique similar to that described by (29).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAfter the temporary reduction of proximal tibial segment, 2.0 mm 6-hole conventional TPLO plate (Jeil TPLO Plates; Jeil Medical Corp.\u0026reg;, Seoul, Republic of Korea) was stabilized, and the Kirschner wire used for temporary fixation was removed prior to compression and final stabilization with screws. All subsequent procedures were performed by a single surgeon (J.W.K) based on earlier surgical planning. The TPLO surgery aimed to achieve a postoperative TPA of 5\u0026deg;\u0026nbsp;(27,30). The surgeon selected either 12 or 15 mm TPLO saw. Pin placement was visually aligned relative to the tibial mechanical axis during surgery. In Group 1 and 2, the pin was intended to be placed perpendicular to the axis, and in Group 3, at an inclined cranial-to-caudal direction. However, no postoperative radiographic or angular measurements were performed to objectively verify the pin orientations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4. Postoperative radiography\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Immediate postoperative radiographs (Figure 2) were obtained for every limb. On these images the ATTW, TPA, and rotation length were measured. A limb was accepted for further analysis only if it met all three radiographic criteria: (1) a postoperative TPA of 0\u0026ndash;14\u0026deg; (30,31); (2) no discernible osteotomy gap; and (3) secure bicortical screw purchase. Specimens that failed to satisfy any one of these thresholds were discarded and replaced with newly prepared limbs. All measurements were obtained in triplicate, in a single session, by the same investigator (J.W.K.).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5. Biomechanical evaluation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eFor biomechanical testing, the hock and stifle joints were disarticulated, retaining only the tibia with the TPLO construct, the patella, PL, and the distal 4 cm of the quadriceps muscle. Each specimen was secured to a wooden board angled at 135\u0026deg; to the tibial axis to simulate the mid-stance phase of gait (16,32,33). A 1.8 mm Steinmann pin was inserted through the tibial shaft into the board for fixation, and three additional 2.0 mm cortical screws were placed in the proximal and distal tibia to counteract rotational forces\u003cstrong\u003e.\u003c/strong\u003e Incremental tensile force was then applied to the quadriceps muscle via a custom gripping jig (Figure 3).\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eVertical distraction was performed at a constant displacement rate of 10 mm/min using a mechanical testing machine (Instron 5585; Instron Corp.\u0026reg;, Norwood, MA, USA) until tibial tuberosity failure occurred. Failure was defined as the first abrupt drop in the load-displacement curve. The primary outcome measure was the maximum failure load (N) of the tibial tuberosity under vertical tensile force. Radiographs were obtained post-failure to document the fracture configuration and location. Parameters recorded for each specimen included pre-osteotomy tibial width (mm), post-osteotomy ATTW (mm), TPA (\u0026deg;), maximum failure load (N), and mode of failure.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.6. Statistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll statistical analyses were conducted using SPSS software v.30.0.0.0 (IBM Corp., Armonk, NY, USA). Due to the small sample size in each of the three groups, non-parametric tests were employed. Group comparisons were conducted using the Kruskal\u0026ndash;Wallis test, followed by post hoc pairwise analysis using the Mann\u0026ndash;Whitney U test with Bonferroni correction. A p-value \u0026lt; 0.017 was considered statistically significant. No blinding was applied in this study. All procedures, including specimen preparation, group allocation, TPLO, and outcome measurement, were jointly conducted by two investigators (J.W.K. and J.M.K.).\u0026nbsp;\u003c/p\u003e"},{"header":"Ⅲ. Results","content":"\u003cp\u003eEighteen hindlimbs were harvested from nine skeletally mature small-breed canine cadavers between March 2024 and January 2025. The mean body weights were similar across Groups (G1: 6.04\u0026thinsp;\u0026plusmn;\u0026thinsp;1.19 kg, G2: 5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08 kg, G3: 5.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.37 kg) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), with no statistically significant difference (Kruskal\u0026ndash;Wallis, \u003cem\u003ep\u0026thinsp;=\u003c/em\u003e\u0026thinsp;0.975).\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Pre- and Postoperative ATTW and TPA\u003c/h2\u003e \u003cp\u003eThere were no statistically significant differences among the Groups in either ATTW or TPA at both the preoperative (ATTW, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.874; TPA, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.717) or postoperative (ATTW, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.352; TPA, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.874) time points, as determined by Kruskal\u0026ndash;Wallis testing. The mean postoperative ATTW values were 5.40\u0026thinsp;\u0026plusmn;\u0026thinsp;0.40 mm in Group 1, 5.62\u0026thinsp;\u0026plusmn;\u0026thinsp;0.96 mm in Group 2, and 5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35 mm in Group 3, while the mean postoperative TPA values were 4.33\u0026thinsp;\u0026plusmn;\u0026thinsp;2.16\u0026deg;, 4.70\u0026thinsp;\u0026plusmn;\u0026thinsp;3.28\u0026deg;, and 4.48\u0026thinsp;\u0026plusmn;\u0026thinsp;2.52\u0026deg;, respectively (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003ePre- and postoperative tibial plateau angle (TPA), absolute tibial tuberosity width (ATTW), and body weight\u003c/b\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGroup 1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup 2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup 3\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep value\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative TPA (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27.67\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;4.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.17\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;3.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27.58\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;3.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.717\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative TPA (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.33\u003c/p\u003e \u003cp\u003e\u0026plusmn; 2.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.70\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;3.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.48\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;2.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.874\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative ATTW (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.68\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;0.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.63\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;0.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.90\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;0.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.856\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative ATTW (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.40\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;0.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.62\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;0.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.93\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;0.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.352\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody Weight (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.04\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;1.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.93\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;1.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.98\u003c/p\u003e \u003cp\u003e\u0026plusmn;\u0026thinsp;1.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.972\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eValues are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation.\u003c/p\u003e \u003cp\u003eNo statistically significant differences were detected among Groups at any measurement time point, based on Kruskal\u0026ndash;Wallis analysis (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e \u003cp\u003eGroup 1: Pin at SF; Group 2: Pin 3 mm distal to SF; Group 3: Pin 6 mm distal to SF with an inclined cranial-to-caudal direction.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Maximum Failure Load\u003c/h2\u003e \u003cp\u003eMaximum failure load differed significantly among the three groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0086). Group 1 (326.27\u0026thinsp;\u0026plusmn;\u0026thinsp;62.66 N; 95% CI: 260.29\u0026ndash;391.97) showed significantly greater tensile strength than Group 2 (194.05\u0026thinsp;\u0026plusmn;\u0026thinsp;61.26 N; 95% CI: 129.73\u0026ndash;258.31; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0087) and Group 3 (213.25\u0026thinsp;\u0026plusmn;\u0026thinsp;58.43 N; 95% CI: 151.93\u0026ndash;274.57; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.0152) (Figure. 4). No significant difference was observed between Group 2 and Group 3 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.5887).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Types of Failure\u003c/h2\u003e \u003cp\u003eFailure configurations differed among Groups, exhibiting distinct patterns depending on pin placement (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Group 1 exhibited a mix of comminuted distal tibial crest fractures (n\u0026thinsp;=\u0026thinsp;3) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003eA) and transverse mid-tibial crest fractures, with the latter showing irregular fracture lines (n\u0026thinsp;=\u0026thinsp;3) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003eB). In contrast, all specimens in Group 2 (n\u0026thinsp;=\u0026thinsp;6) demonstrated transverse mid-tibial crest fractures with relatively linear configurations (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003eC). Group 3 consistently showed distal tibial crest transverse fractures (n\u0026thinsp;=\u0026thinsp;6) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003eD), with fracture lines similarly linear to those in Group 2.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eFailure modes observed in each group following tensile testing\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTypes of Failure\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eGroup 1\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eComminuted distal tibial crest fracture(n\u0026thinsp;=\u0026thinsp;3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTransverse mid-tibial crest fracture(n\u0026thinsp;=\u0026thinsp;3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGroup 2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMid-tibial crest fractures with linear configurations (n\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eGroup 3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMid-tibial crest fractures with linear configurations (n\u0026thinsp;=\u0026thinsp;6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eGroup 1: Pin placed at SF; Group 2: Pin placed 3 mm distal to SF; Group 3: Pin placed 6 mm distal to SF with an inclined cranial-to-caudal direction.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Ⅳ. Discussion","content":"\u003cp\u003eThese results of this study demonstrate that the position of the anti-rotation pin has a decisive influence on the tensile strength of the tibial tuberosity following TPLO (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The pin placed at the most cranial location demonstrated significantly higher resistance to failure, confirming the mechanical advantage of engaging the structurally reinforced region near SF. These results highlight pin location as a controllable factor in surgical planning, with the potential to reduce tibial tuberosity fracture by minimizing stress concentrations in the tibial crest.\u003c/p\u003e \u003cp\u003ePost operative tibial tuberosity fracture in TPLO has been associated in several reports, with a set of modifiable risk factors (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan additionalcitationids=\"CR15 CR16 CR17\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e), notably including a shallow residual tibial tuberosity width, excessive TPA correction, greater body weight loading, and malposition of the temporary anti rotation pin. In the present study, radiographic evaluation confirmed that pre and post-operative TPA, ATTW, and body did not differ significantly among the three groups, indicating comparable baseline anatomy and surgical correction (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). With these factors statistically equivalent, the observed differences in maximum tensile failure load can be attributed chiefly to the location of the anti-rotation pin relative to SF.\u003c/p\u003e \u003cp\u003eThe superior biomechanical performance observed in Group 1 can be attributed to two complementary anatomical factors: first, the robust anchoring provided by SF at the cranial tibial tuberosity, and second, the inherently greater bone stock available at this anatomical site compared to distal locations.\u003c/p\u003e \u003cp\u003eSF are specialized collagenous structures that anchor muscles, tendons, ligaments, and periosteum to underlying bone, playing a critical role in biomechanical stability by effectively distributing muscular and ligamentous forces across bone interfaces (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e). According to recent studies in human medicine, these fibers are believed to participate in bone remodeling and reparative responses, suggesting a broader biological relevance in maintaining musculoskeletal stability (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e). Anatomically, SF are most commonly localized in anatomical regions exposed to substantial tensile forces, such as alveolar bone sockets, cranial sutures, and, in particular, entheses where tendons or ligaments integrate with bone tissue (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). In human orthopedic surgery, increasing awareness of the biomechanical significance of SF has prompted a growing emphasis on preserving the structural integrity of tendon-to-bone interfaces, particularly through techniques aimed at minimizing iatrogenic disruption (\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e). In veterinary medicine, specifically during TPLO, clinical observations have suggested a greater predisposition to tibial tuberosity fractures when the temporary pin were placed distal to SF insertion (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). This finding suggests that placing the pin distal to SF may impair local biomechanical integrity and increase susceptibility to avulsion fractures at the tibial tuberosity.\u003c/p\u003e \u003cp\u003eSeveral studies have highlighted the crucial role of tibial tuberosity morphology in fracture prevention and noted considerable individual variation in the location of the PL insertion (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e). According to Mehrkens \u003cem\u003eet al\u003c/em\u003e., an evaluation of the tibial tuberosity\u0026rsquo;s shape in relation to the PL insertion revealed that tuberosities exhibiting their narrowest point distal to the PL were significantly more susceptible to fractures compared with those that tapered above or at the PL insertion. These findings emphasize the importance of both bone stock and tuberosity geometry in preventing postoperative complications, particularly during TPLO.\u003c/p\u003e \u003cp\u003eIn the present study, distal pin placement where the tibial tuberosity is inherently thinner, was associated with a marked reduction in maximum failure load, further confirming that limited bone stock substantially compromises mechanical integrity (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e6\u003c/span\u003e). By contrast, pinning near to SF, which coincides with greater bone stock and robust tendon-bone attachments, appears to capitalize on the enhanced structural support (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e6\u003c/span\u003e). These observations suggest that pinning near SF, characterized by greater bone stock and stronger tendon-bone anchorage, may improve mechanical stability and reduce the risk of tibial tuberosity fractures. If pin placement is planned distal to the SF whether for supplementary stabilization or due to inadvertent placement, maintaining the pin as a permanent fixture rather than temporary fixation to reduce the risk of creating a stress riser at the insertion site is suggested.\u003c/p\u003e \u003cp\u003eNotably, the retrospective clinical study found no significant association between the vertical position of the anti-rotation pin and the incidence of tibial tuberosity fractures (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). This discrepancy may be partly explained by differences in patient population, as that study primarily involved medium- to large-breed dogs. In such breeds, the tibial crest typically provides more robust bone stock, potentially mitigating the mechanical consequences of distal pin placement. In contrast, the current study exclusively involved small-breed dogs, in which limited bone stock in the tibial crest, has been identified as a significant surgical challenge (\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e). These anatomical differences may help explain the inconsistent findings, though further validation is needed.\u003c/p\u003e \u003cp\u003eThe similar failure loads between Group 2 and 3 observed in present study may be attributed to the fact that both pin placements remained within the tibial crest, a region where bone stock is relatively uniform from its mid to distal extent, resulting in minimal variation in biomechanical resistance. It is plausible that positioning the pin distal to the tibial crest, where bone stock markedly is increased, might yield different mechanical outcomes. Further research examining the biomechanical consequences of pin placements distal to the tibial crest is needed.\u003c/p\u003e \u003cp\u003eFracture configurations observed in this study under tensile loading revealed distinct patterns based on the pin's vertical positioning relative to SF (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Specimens in Group 1, with the pin placed directly at SF, exhibited either comminuted distal tibial crest fractures or transverse mid-tibial crest fractures with irregular fracture lines. These diverse fracture patterns suggest a robust and uneven load distribution across the tibial tuberosity, reflecting the strong structural support provided by the abundant SF and substantial bone stock in the most cranial aspect of tibial tuberosity. Conversely, all specimens in Group 2 and 3 consistently demonstrated transverse mid-tibial crest fractures with relatively linear fracture configurations. Such uniform failure patterns indicate a predictable but mechanically weaker region, particularly when the pin was positioned more distally, where bone stock is reduced, and SF density is diminished. These observations reinforce the biomechanical importance of optimal pin placement relative to the SF insertion, highlighting the need for precise surgical planning to mitigate fracture risks during TPLO procedures in clinical settings. Indeed, similar mid-crest fractures have been commonly documented in retrospective clinical studies where the anti-rotation pin was positioned more distally (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). This consistency between experimental and clinical findings further underscores the vulnerability associated with distal pin placement.\u003c/p\u003e \u003cp\u003eIn relation to the forces acting through the stifle joint during canine gait, a previous study utilizing three-dimensional biomechanical modeling indicated that quadriceps muscle force during a slow walk can vary substantially depending on the stifle flexion angle, ranging from approximately 16.5% up to 94.8% of the dog's body weight (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e). Typical stifle flexion angles during mid-stance are generally reported between 120\u0026deg; and 140\u0026deg;, consistent with previously documented canine gait mechanics (\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e). Given this physiological context and considering the body weight range of the small-breed dogs in present study (4.0\u0026ndash;7.9 kg; approximately 39\u0026ndash;78 N), it is reasonable to estimate that the quadriceps force exerted on the tibial tuberosity during slow walking may fall within a comparable proportion of the vertical ground reaction force, likely approaching 95%. Accordingly, the muscular load would be expected to range between approximately 37 and 74 N, although interindividual variability and gait asymmetry could influence the actual force transmission. These estimated forces are considerably lower than the lowest maximum tensile failure load measured in current study (approximately 194 N), suggesting that immediate structural failure is unlikely during normal walking activities in clinical situations. Nevertheless, it must be recognized that Shahar\u0026rsquo;s model provides only an approximation of quadriceps force during slow walking and does not account for higher-intensity activities such as trotting, jumping, or stair climbing, all of which likely impose substantially greater loads on the quadriceps mechanism. Further biomechanical investigations incorporating dynamic loading conditions and a broader range of functional activities are warranted to better elucidate the mechanical demands placed on the tibial tuberosity in vivo.\u003c/p\u003e \u003cp\u003eDespite the biomechanical insights provided by this study, several experimental limitations must be acknowledged. The exclusive use of small-breed canine limbs limits the applicability of these results to larger breeds with different anatomical characteristics. Moreover, the cadaveric nature of this investigation precluded physiological responses such as bone remodeling and SF development, which are critical to long-term fixation stability. Histologic evidence from in vivo studies indicates that SF begin to form around eight weeks postoperatively in dogs (\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e). Their morphology is influenced by biological variables including age, hormonal status, and bone disease, emphasizing the need for complementary in vivo research to elucidate these interactions (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eStatic axial loading failed to replicate cyclic mechanical stress experienced during ambulation, which may critically influence tibial tuberosity stress over time. Given that clinical fractures often occur between two and six weeks postoperatively(\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e), future studies incorporating dynamic loading models are warranted to enhance clinical relevance.\u003c/p\u003e \u003cp\u003ePin placement was visually aligned intraoperatively, but no radiographic or angular measurements were conducted to confirm precise orientation relative to the tibial axis, limiting repeatability. Additionally, removal of periarticular soft tissues and absence of donor histories prevented assessment of structural stabilizers and underlying pathology, further limiting clinical extrapolation.\u003c/p\u003e \u003cp\u003eNevertheless, the findings of this study clearly emphasize that precise positioning of the temporary anti-rotation pin near SF significantly enhances biomechanical stability, potentially reducing the risk of postoperative tibial tuberosity fractures in small-breed dogs undergoing TPLO. Further in vivo studies incorporating dynamic loading conditions, breed-specific anatomical variations, and dogs of various sizes are required to overcome the inherent limitations of this ex vivo investigation and fully validate these biomechanical outcomes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Ⅴ. Conclusion","content":"\u003cp\u003eThis study demonstrates that positioning the anti-rotation pin at SF in tibial tuberosity significantly enhances the biomechanical strength and reduces fracture risk following TPLO in small-breed dogs. Distal pin placement compromises structural integrity due to limited bone stock, increasing fracture susceptibility. Clinically, optimal pin placement at SF is recommended to minimize complications.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eSF : Sharpey\u0026rsquo;s Fibers\u003c/p\u003e\n\u003cp\u003eCCLD: Cranial Cruciate Ligament Disease\u003c/p\u003e\n\u003cp\u003eTPLO: Tibial Plateau Leveling Osteotomy\u003c/p\u003e\n\u003cp\u003eATTW: Apical Tibial Tuberosity Width\u003c/p\u003e\n\u003cp\u003eTPA: Tibial Plateau Angle\u003c/p\u003e\n\u003cp\u003ePL: Patellar Ligament\u003c/p\u003e\n\u003cp\u003eSD: Standard Deviation\u003c/p\u003e\n\u003cp\u003eCI: Confidence Interval\u003c/p\u003e\n\u003cp\u003eBW: Body Weight\u003c/p\u003e\n\u003cp\u003eN: Newton\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eNot applicable. This study used canine cadaveric limbs sourced from animals euthanized for reasons unrelated to this research.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article and its supplementary information files.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThis study was supported by the Graduate School Research Program of Konkuk University (Seoul, Republic of Korea). The funding body had no role in study design, data collection, analysis, interpretation, or manuscript preparation.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eJ.W. Kim and J.M. Kim contributed equally as co-first authors. They jointly performed all experimental procedures, including cadaveric limb preparation, TPLO surgery, data collection, and manuscript writing. J.S. Cho conducted statistical analyses, created all figures, and assisted in experimental design and execution. K. Lee, J. Jo, and J.H. Kim contributed to cadaveric preparation and participated in all stages of the experiments. S.K. Jang and S.Y. Lee supported specimen handling and procedural assistance as research veterinarians. H.Y. Kim supervised the entire study, including experimental design and scientific oversight, as the corresponding author. All authors reviewed and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eThe authors thank the Clinical Research Laboratory and the Department of Veterinary Surgery at Konkuk University for providing technical assistance and institutional resources during this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJohnston SA, Tobias KM, editors. Veterinary surgery: small animal. Second edition. St. Louis, Missouri: Elsevier; 2018. \u003c/li\u003e\n\u003cli\u003eRafla M, Yang P, Mostafa A. Canine Cranial Cruciate Ligament Disease (CCLD): A Concise Review of the Recent Literature. Animals. 2025 Apr 3;15(7):1030. \u003c/li\u003e\n\u003cli\u003eDuval JM, Budsberg SC, Flo GL, Sammarco JL. Breed, sex, and body weight as risk factors for rupture of the cranial cruciate ligament in young dogs. 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Comparison of TPLO tibial tuberosity fractures with and without an in situ rotational pin. BMC Res Notes. 2018 Dec;11(1):368. \u003c/li\u003e\n\u003cli\u003ePacchiana PD, Morris E, Gillings SL, Jessen CR, Lipowitz AJ. Surgical and postoperative complications associated with tibial plateau leveling osteotomy in dogs with cranial cruciate ligament rupture: 397 cases (1998\u0026ndash;2001). javma. 2003 Jan 15;222(2):184\u0026ndash;93. \u003c/li\u003e\n\u003cli\u003ePriddy NH, Tomlinson JL, Dodam JR, Hornbostel JE. Complications with and owner assessment of the outcome of tibial plateau leveling osteotomy for treatment of cranial cruciate ligament rupture in dogs: 193 cases (1997\u0026ndash;2001). javma. 2003 Jun 15;222(12):1726\u0026ndash;32. \u003c/li\u003e\n\u003cli\u003eStauffer KD, Tuttle TA, Elkins AD, Wehrenberg AP, Character BJ. Complications Associated With 696 Tibial Plateau Leveling Osteotomies (2001\u0026ndash;2003). Journal of the American Animal Hospital Association. 2006 Jan 1;42(1):44\u0026ndash;50. \u003c/li\u003e\n\u003cli\u003eResearch Randomizer [Internet]. [cited 2025 May 29]. Available from: https://www.randomizer.org/\u003c/li\u003e\n\u003cli\u003eDismukes DI, Tomlinson JL, Fox DB, Cook JL, Song KJE. Radiographic Measurement of the Proximal and Distal Mechanical Joint Angles in the Canine Tibia. Veterinary Surgery. 2007 Oct;36(7):699\u0026ndash;704. \u003c/li\u003e\n\u003cli\u003eSlocum B, Devine T. Cranial tibial thrust: a primary force in the canine stifle. J Am Vet Med Assoc. 1983 Aug 15;183(4):456\u0026ndash;9. \u003c/li\u003e\n\u003cli\u003eKowaleski MP, McCarthy RJ. Geometric analysis evaluating the effect of tibial plateau leveling osteotomy position on postoperative tibial plateau slope. Vet Comp Orthop Traumatol. 2004 Jan;17(01):30\u0026ndash;4. \u003c/li\u003e\n\u003cli\u003eJeong E, Jeon Y, Kim T, Lee D, Roh Y. Assessing the Effectiveness of Modified Tibial Plateau Leveling Osteotomy Plates for Treating Cranial Cruciate Ligament Rupture and Medial Patellar Luxation in Small-Breed Dogs. Animals. 2024 Jun 30;14(13):1937. \u003c/li\u003e\n\u003cli\u003eTan CJ, Bergh MS, Schembri MA, Johnson KA. Accuracy of Tibial Osteotomy Placement Using 2 Different Tibial Plateau Leveling Osteotomy Jigs. Veterinary Surgery. 2014 Jul;43(5):525\u0026ndash;33. \u003c/li\u003e\n\u003cli\u003eJay MR, Mattoon JS, Gilbert PJ, Tanaka TT, Beaty BL. Radiographic evaluation of patellar ligament length after tibial plateau leveling osteotomy in dogs. ajvr. 2019 Jun;80(6):607\u0026ndash;12. \u003c/li\u003e\n\u003cli\u003eTalaat MB, Kowaleski MP, Boudrieau RJ. Combination Tibial Plateau Leveling Osteotomy and Cranial Closing Wedge Osteotomy of the Tibia for the Treatment of Cranial Cruciate Ligament‐Deficient Stifles with Excessive Tibial Plateau Angle. Veterinary Surgery. 2006 Dec;35(8):729\u0026ndash;39. \u003c/li\u003e\n\u003cli\u003eVolz F, Eberle D, Klever J, Zablotski Y, Kornmayer M. Effect of tibial plateau angle \u0026lt; 5\u0026deg; on ground reaction forces in dogs treated with tibial plateau leveling osteotomy for cranial cruciate ligament rupture up to 6 months postoperatively. The Veterinary Journal. 2024 Jun 1;305:106126. \u003c/li\u003e\n\u003cli\u003eRobinson DA, Mason DR, Evans R, Conzemius MG. The Effect of Tibial Plateau Angle on Ground Reaction Forces 4\u0026ndash;17 Months After Tibial Plateau Leveling Osteotomy in Labrador Retrievers. Veterinary Surgery. 2006 Apr;35(3):294\u0026ndash;9. \u003c/li\u003e\n\u003cli\u003eShahar R, Banks-Sills L. Biomechanical Analysis of the Canine Hind Limb: Calculation of Forces During Three-legged Stance. The Veterinary Journal. 2002 May;163(3):240\u0026ndash;50. \u003c/li\u003e\n\u003cli\u003eShahar R, Banks-Sills L. A quasi-static three-dimensional, mathematical, three-body segment model of the canine knee. Journal of Biomechanics. 2004;37(12):1849\u0026ndash;59. \u003c/li\u003e\n\u003cli\u003eAaron JE. Periosteal SF: a novel bone matrix regulatory system? Front Endocrin [Internet]. 2012 [cited 2025 Jan 24];3. Available from: http://journal.frontiersin.org/article/10.3389/fendo.2012.00098/abstract\u003c/li\u003e\n\u003cli\u003eLui P, Zhang P, Chan K, Qin L. Biology and augmentation of tendon-bone insertion repair. J Orthop Surg Res. 2010;5(1):59. \u003c/li\u003e\n\u003cli\u003eTsarouhas A, Hantes ME. Bone-Tendon and Bone-Ligament Interface. In: Karachalios T, editor. Bone-Implant Interface in Orthopedic Surgery [Internet]. London: Springer London; 2014 [cited 2025 Jan 24]. p. 307\u0026ndash;25. Available from: https://link.springer.com/10.1007/978-1-4471-5409-9_21\u003c/li\u003e\n\u003cli\u003eDuerr FM, Duncan CG, Savicky RS, Park RD, Egger EL, Palmer RH. Comparison of Surgical Treatment Options for Cranial Cruciate Ligament Disease in Large‐Breed Dogs with Excessive Tibial Plateau Angle. Veterinary Surgery. 2008 Jan;37(1):49\u0026ndash;62. \u003c/li\u003e\n\u003cli\u003eFujino H, Honnami M, Mochizuki M. Preoperative planning for tibial plateau leveling osteotomy based on proximal tibial width. J Vet Med Sci. 2020;82(5):661\u0026ndash;7. \u003c/li\u003e\n\u003cli\u003eHackett M, St Germaine L, Carno MA, Hoffmann D. Comparison of Outcome and Complications in Dogs Weighing Less Than 12 kg Undergoing Miniature Tibial Tuberosity Transposition and Advancement versus Extracapsular Stabilization with Tibial Tuberosity Transposition for Cranial Cruciate Ligament Disease with Concomitant Medial Patellar Luxation. Vet Comp Orthop Traumatol. 2021 Mar;34(02):099\u0026ndash;107. \u003c/li\u003e\n\u003cli\u003eRodeo SA, Arnoczky SP, Torzilli PA, Hidaka C, Warren RF. Tendon-healing in a bone tunnel. A biomechanical and histological study in the dog.: The Journal of Bone \u0026amp; Joint Surgery. 1993 Dec;75(12):1795\u0026ndash;803. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"small breed dogs, tibial plateau leveling osteotomy, tibial tuberosity fracture, anti-rotation pin, Sharpey’s fibers, tensile test","lastPublishedDoi":"10.21203/rs.3.rs-6783640/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6783640/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eTibial Plateau Leveling Osteotomy (TPLO) is widely accepted for stabilizing the stifle joint in dogs with cranial cruciate ligament disease. However, postoperative tibial tuberosity fractures remain a significant complication, particularly in small-breed dogs. Recent anatomical findings suggest that Sharpey\u0026rsquo;s fibers(SF) contribute to local structural reinforcement, yet the biomechanical implications of anti-rotation pin positioning relative to these fibers have not been experimentally quantified.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eEighteen pelvic limbs from nine small-breed canine cadavers (mean body weight 5.98 kg) were assigned to three groups (n\u0026thinsp;=\u0026thinsp;6) based on anti-rotation pin positioning. Group 1 had the pin inserted perpendicular to the tibial mechanical axis at the level of SF. Group 2 received pin placement 3 mm distal, and Group 3 received placement 6 mm distal and inclined from cranial to caudal. All limbs underwent standardized TPLO, followed by mounting at a standing angle of 135\u0026deg;, and vertical tensile force was applied until failure. Pre- and postoperative tibial plateau angle (TPA) and absolute tibial tuberosity width (ATTW) were measured to ensure anatomical consistency. Group 1 exhibited significantly higher maximum failure loads compared to Groups 2 and 3 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.017), with no significant difference between the latter two. Fracture configuration differed notably: Group 1 showed complex, comminuted fractures of the distal tibial crest, while Groups 2 and 3 demonstrated simple linear transverse fractures at the mid-crest region.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003ePlacement of the anti-rotation pin at the level of SF significantly enhances biomechanical resistance of the tibial tuberosity under tensile loading following TPLO. These findings support precise vertical pin positioning as a modifiable surgical variable to reduce fracture risk in small-breed dogs. Further in vivo studies incorporating dynamic loading and breed-specific anatomical variation are warranted to confirm these ex vivo results.\u003c/p\u003e","manuscriptTitle":"Optimal Placement of Temporary Anti-rotation Pin in Tibial Plateau Leveling Osteotomy: A Canine Ex Vivo Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-01 09:08:08","doi":"10.21203/rs.3.rs-6783640/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-04T10:38:06+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"201579040335664520094716494411858968452","date":"2025-07-03T20:40:50+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-03T17:11:25+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-28T02:50:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"224332283920274898132821940094536392086","date":"2025-06-28T00:43:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"76653104741026728152761868186158315233","date":"2025-06-27T17:29:32+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-27T09:38:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"123962356152961567719767211774612746372","date":"2025-06-25T18:09:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"234400005207037477309233087803237052366","date":"2025-06-25T14:22:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"8801755564153712264334766547819899615","date":"2025-06-25T13:24:00+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-25T13:15:51+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-06-24T07:33:54+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-02T06:44:53+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-02T06:43:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Veterinary Research","date":"2025-05-30T10:04:10+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c97c1d03-b3ba-4022-96ae-35bba5a3fbc8","owner":[],"postedDate":"July 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-03T16:04:23+00:00","versionOfRecord":{"articleIdentity":"rs-6783640","link":"https://doi.org/10.1186/s12917-025-05065-4","journal":{"identity":"bmc-veterinary-research","isVorOnly":false,"title":"BMC Veterinary Research"},"publishedOn":"2025-10-31 15:57:46","publishedOnDateReadable":"October 31st, 2025"},"versionCreatedAt":"2025-07-01 09:08:08","video":"","vorDoi":"10.1186/s12917-025-05065-4","vorDoiUrl":"https://doi.org/10.1186/s12917-025-05065-4","workflowStages":[]},"version":"v1","identity":"rs-6783640","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6783640","identity":"rs-6783640","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}