Clinical Differences Between Periprosthetic and Native Distal Femur Fractures

Clinical Differences Between Periprosthetic and Native Distal Femur Fractures | 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 Clinical Differences Between Periprosthetic and Native Distal Femur Fractures Shana Kong, Barry Bautista, Max Haffner, Judas Kelley, Kelsey Hideshima, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4032916/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Introduction Periprosthetic distal femur fractures (PDFF) are becoming more prevalent as total knee replacements become more common. This study compares the demographics, fracture characteristics, treatment, and outcomes of periprosthetic versus native distal femur fractures (NDFF). Materials and Methods This is a retrospective cohort study of patients ≥ 18 who underwent surgical fixation of NDFF or PDFF from 2012-2020 at a level-1 trauma center. Primary outcomes included demographics, AO/OTA fracture classification, fixation construct, and unexpected return to the operating room (UROR). Secondary outcomes were concomitant fractures, polytrauma rates, low bone density, and reduction quality. T-test, Fisher’s exact test, and multivariable analysis were used for statistical analysis. Results 209 patients were identified, including 70 PDFF and 139 NDFF. PDFF patients were elderly females (81%) with isolated (80%) and comminuted (85%) 33A.3 (71%) fractures. NDFF patients included 53% females, were commonly middle-aged, and displayed comminuted (92%) 33C.2 fractures. 48% of NDFF patients had concomitant fractures. Intramedullary nailing was the primary fixation for both groups, followed by nail-plate combination (37%) for PDFF and lateral locking plates (21%) for NDFF. NDFF patients experienced lengthier hospital stays and higher UROR rates (p<0.05). PDFF patients had a significantly higher prevalence of low bone density (p<0.05). Conclusion PDFF occur as isolated injuries with significant metaphyseal comminution in elderly females with low bone quality. NDFF commonly occurs in younger patients with less metaphyseal comminution and concomitant fractures. Intramedullary nailing was the most common treatment for both groups, though preference for nail-plate combination fixation is increasing. NDFF type 33C fractures are at higher risk of UROR. Figures Figure 1 Figure 2 Figure 3 Introduction In 2012, total knee arthroplasty (TKA) was the single most common surgical procedure performed in the United States, with 94% of those procedures occurring in patients 65-84 years old [1], [2]. As the population ages and the prevalence of TKA rises, the frequency of periprosthetic distal femur fractures (PDFF) has simultaneously increased. Multiple studies report that distal femur fractures are the most common type of periprosthetic fracture occurring above a TKA [4], [5], [6]. Court-Brown et al. reported an increase in PDFF prevalence from 15.4% to 27.8% of all distal femur fractures from 2007-2011 [7]. Treatment of PDFF presents a challenge for orthopedic surgeons, who must not only take into consideration the complex and variable fracture morphology associated with the prosthesis but also the specific populations at risk. Previous literature has focused on analyzing PDFF and native distal femur fractures (NDFF) separately. Roy et al. analyzed NDFF exclusively at a single level-1 trauma center and characterized the affected population as middle-aged, female (66%), and more often overweight than osteoporotic [8]. Additionally, they identified similar rates of high-and low-energy trauma in their NDFF cohort and found that high-energy type injuries were associated with more severe fracture types (AO/OTA 33B/C), open fractures, and additional orthopedic injuries, while low-energy injuries were associated with closed fractures and less severe fracture types (AO/OTA 33A) [8]. Elsoe et al. first reported on the demographics of PDFF, noting a population distribution of elderly females (mean age=77) with low-energy injuries [9]. Regarding treatment, lateral plating and retrograde intramedullary nailing (rIMN) have been reported as the most common and successful fixations for both PDFF and NDFF, although intramedullary nail-plate combination (NPC) fixation has recently been developed as an additional treatment alternative [10], [11], [12] [13], [14]. Studies report similar 30-day and 90-day outcomes, though longer-term outcomes and reduction quality have yet to be studied [15], [16]. In the existing body of literature, there is a notable lack of comprehensive comparisons between PDFF and NDFF within single institutions. Studies have focused exclusively on one fracture type without directly comparing it with the other. As a result, there is limited understanding of the relative differences between PDFF and NDFF in terms of demographics, fracture characteristics, treatment modalities, and outcomes. Therefore, the primary objective of this study is to conduct a detailed comparison of PDFF and NDFF using data from a single large cohort within our institution. While there is some consistency in the literature regarding these fracture types, there remains a need to systematically examine and compare them within the same population to further denote remaining discrepancies which may arise from limited generalizability. Furthermore, a secondary aim is to explore aspects such as the quality of reduction and long-term outcomes, which have not been extensively studied in prior literature. These analyses are critical as they have the potential to provide valuable insights that can guide future treatment strategies and improve patient outcomes. We hypothesize that PDFF are more likely to be isolated, simple, low-energy, injuries experienced by elderly patients while NDFF will be experienced by a younger population and result in more complicated fracture patterns due to higher levels of trauma. Furthermore, we hypothesize there will be no difference in postoperative outcomes between PDFF and NDFF groups. Methods Cohort Selection This retrospective study was approved by the Institutional Review Board. All patients who were at least 18 years of age at the time of admission with distal femur fractures between January 1 st , 2012 and December 31 st , 2020 at a single level-1 trauma center were identified. These patients were later classified as either NDFF or PDFF. Patients with bilateral distal femur fractures were not included. Data Collection Electronic medical records were used to obtain clinical data and demographics for each patient. American Society of Anesthesiologists (ASA) score and bone density status were obtained from clinical notes. Presence of bone loss, classified as either osteopenia or osteoporosis, was determined by either previous diagnosis documented in the patient chart or by comments noted by radiologists from existing radiographs. Fracture characteristics including AO/OTA fracture classifications were obtained from pre-operative radiographs and computed tomography (CT) scans. Polytrauma was noted if present and defined as having two or more injuries affecting two or more bodily areas. Type of surgical fixation was obtained from operative notes and radiographs. Patients with NPC fixation were categorized separately and did not contribute to nail or plate counts. Post-operative outcome data was obtained using follow-up notes and immediate post-operative radiographs. Quality of reduction was assessed by calculating the difference in alignment from the population average anatomic lateral distal femoral angle (aLDFA) on post-operative anteroposterior (AP) radiographs. To measure the aLDFA (Figure 3), a line was first drawn parallel to both femoral condyles of the affected femur, representing the knee joint line. Next, a line was drawn from the center of the femoral head to the intercondylar notch of the affected femur, representing the mechanical axis of the femur. The lateral angle formed between the mechanical axis of the femur and the knee joint line was recorded in degrees as the aLDFA. The aLDFA for the contralateral, unaffected femur was also calculated if contralateral films had been acquired. The mean difference from the population average aLDFA of 81 degrees was calculated in the affected and unaffected femurs for both PDFF and NDFF groups. A smaller deviation from the population average aLDFA was accepted as a more desired outcome. Statistical Analyses Differences between PDFF and NDFF patients were compared using Fisher’s exact test, unpaired t-test, or multivariate analysis, as appropriate for each variable using Microsoft Excel. Multivariate analysis was completed in Excel using a linear regression with all variables included. Results were described using incidence rates, means, and one standard deviation. Statistical significance was assigned as p<0.05. Results Table 1 summarizes the pre-operative characteristics of both cohorts. The mean age of NDFF patients was 23 years younger than the PDFF patients (p<0.001). There were significantly fewer females in the NDFF cohort (53% compared to 81%, p<0.001). The PDFF cohort had higher rates of bone loss (55.7% compared to 19.4%, p<0.001). There was no significant difference between ASA scores of both cohorts (p=0.061). Table 2. Fracture Characteristics of NDFF and PDFF patients NDFF PDFF P-value AO/OTA classification 33A.2 Extra-articular Simple fracture 6% 29% <0.001 a 33A.3 Extra-articular Wedge or Multifragmentary Fracture 25% 71% <0.001 a 33C.1 Simple Articular, Simple metaphyseal 6% 0% 0.215 a 33C.2 Simple Articular Wedge or Multifragmentary Metaphyseal 28% 0% <0.001 a 33C.3 Multifragmentary Articular, Simple, Wedge or Multifragmentary metaphyseal 22% 0% <0.001 a 33B.1 Partial Articular Lateral Condyle 12% 0% <0.05 a 33B.3 Frontal/Coronal 2% 0% 0.552 a Isolated Injury 51.8% 80% <0.001 a Polytrauma 41% 18.6% <0.001 a Open 30.7% 11.2% 0.002 a Comminution 85% 92.1% 0.274 a Interprosthetic Fracture - 24.3% - a Fisher’s exact test Table 2 summarizes the fracture characteristics of the two cohorts. 33A.2 and 33A.3 classifications represented the entirety of PDFF. In comparison, NDFF AO/OTA classifications were represented by 33C.2 (28%), 33C.3 (22%), and 33B.1 (12%), which were significantly more prevalent than in the PDFF cohort (p<0.001 for 33C.3 and 33C.3, and p<0.05 for 33B.1). Table 2 also shows significant differences in the rate of isolated injuries and polytraumas between both cohorts. PDFF were more often isolated injuries in patients (80% versus 51.8%, p<0.001). NDFF patients were more likely to be polytraumatized (41% compared to 18.6%, p<0.001). Additionally, NDFF patients also had higher rates of open fractures (30.7% compared to 11.2%, p=0.002). There was no significant difference between the comminution rates of fractures in both cohorts (p=0.274). Table 3. Surgical Fixation Construct Used in NDFF and PDFF patients Fixation Construct NDFF PDFF P-value Intermedullary Nail 36.7% 44.3% 0.297 a Nail Plate Combination 17.2% 37.1% <0.05 a Lateral Plate 20.8% 14.3% 0.266 a Medial Plate 5.8% 0% 0.053 a Lag Screws 6.5% 0% <0.05 a Other 12.9% 4.3% - a Fisher’s exact test Table 3 summarizes the surgical fixation constructs used for both cohorts. Retrograde intermedullary nail was the most common fixation utilized in both groups, and there was no significant difference in the prevalence of rIMN between the two groups (NDFF = 36.7%, PDFF = 44.3%, p=0.297). NDFF patients had higher rates of medial plate usage (5.8% compared to 0%, p<0.05) and PDFF patients had higher rates of NPC used as fixation constructs (37.1% compared to 17.2%, p<0.05). Further analysis of NPC usage revealed usage beginning in 2015 for both groups, with prevalence of usage rising from 3.3% and 0.7% to 13.3% and 4.3% in 2019 (PDFF) and 2020 (NDFF) respectively. Table 4. Postoperative Outcomes of PDFF and NDFF patients Measure NDFF PDFF P-value Any Re-operation Occurrence 19 (13.6%) 6 (8.5%) <0.05 a Malunion 1 ( 0.7%) 1 (1.4%) -- Nonunion 4 ( 2.8%) 2 (2.8%) -- Revision 1 ( 0.7%) 1 (2.9%) -- Irrigation and Debridement 7 ( 5%) 0 -- Stiff Knee 2 (1.4%) 0 -- Painful Orthopedic Hardware 0 2 (2.8%) -- Re-injury 1 ( 0.7%) 0 -- Septic Arthritis 1 ( 0.7% ) 0 -- Skin Necrosis 1 (0.7) Foreign Body Removal 1 (0.7% ) 0 -- Length of Stay (days) 11.4 ± 16.6 6.36 ± 5.74 <0.05 b Length of Follow-up (days) 148 ± 181 164 ± 204 0.564 b Deviation of affected side from standard aLDFA (degrees) 9.06 ± 11.1 3.04 ± 2.86 <0.001 b Deviation of contralateral side from standard aLDFA (degrees) 2.92 ± 3.97 (n=9) 1.7 ± 0 (n=1) -- a Multivariate analysis b Unpaired t-test c Anterior-Posterior Post-operative outcomes are summarized in Table 4. Patients in the NDFF cohort had an approximately five-day longer length of stay compared to the PDFF cohort (p<0.05). There was no significant difference in length of follow-up between both cohorts (p=0.564). NDFF patients had higher rates of any unexpected return to the operating room (UROR) occurrences compared to their PDFF counterparts (13.6% compared to 8.5%, p<0.05). Out of the 19 NDFF requiring reoperation, 10 (52%) were AO/OTA type 33C fractures. Irrigation and debridement of the femur fracture of interest due to infection was the leading cause for UROR for NDFF patients (5% compared to 0%). The revision operation within the NDFF cohort was due to intra-articular prominence of an intramedullary nail, and the other revision within the PDFF cohort was due to implant failure with valgus angulation. PDFF patients had significantly improved quality of reduction with respect to the average population aLDFA of 81 degrees. The mean aLDFA in PDFF patients was approximately 6 degrees less in deviation compared to NDFF patients (p<0.001). In addition, when using the non-injured contralateral aLDFA, PDFF were approximately 1.2 degrees less in deviation. However, significance could not be gathered given the limited availability of contralateral imaging. Discussion This study is the first to directly compare native and periprosthetic distal femur fractures. PDFF were found to be commonly isolated injuries with complete metaphyseal comminution, affecting elderly women and those with low bone quality. NDFF, on the other hand, tended to occur in younger patients with less metaphyseal comminution and additional fractures. The study highlighted that the NDFF group had increased revision reoperation rates compared to PDFF, specifically for irrigation and debridement of the femur fracture of interest. Multivariate regress analysis revealed that NDFF are an independent risk factor for reoperation, specifically irrigation and debridement of the fracture of interest, compared to PDFF. The present study reports a PDFF gender distribution similar to Elsoe et al., who documented a sample of mostly females with a mean age of 77 years old [17]. Additionally, our PDFF sample was characterized by a high prevalence of low bone density. Low bone density has been highlighted as a risk factor for femur fractures in past studies, and low-energy distal femur fractures are now considered fragility fractures [7], [18]. This study reports the exact rate of low bone density (osteopenia or osteoporosis) in our PDFF population. Although trauma mechanisms were not formally investigated in our study, we saw that PDFF were mostly isolated injuries, which is more suggestive of a low-energy trauma mechanism as proposed by prior studies [19], [20]. The most common fracture pattern for PDFF was extraarticular with complete metaphyseal comminution (AO/OTA 33A.3). The increased metaphyseal comminution is likely related to both the presence of low bone quality and the TKA affecting the stress concentration locations of the fracture. Low bone quality leads to an overall decreased tolerance for withstanding forces. Additionally, with the TKA present, the fracture cannot propagate into the joint, and more energy may be imparted to the metaphysis. While previous studies have documented rIMN and lateral locked plating as the most common method of treatment for PDFF, our study has identified rIMN and NPC fixation to be the most common methods utilized at our institution [11], [21], [22]. Further analysis of NPC fixation rates revealed an increase in prevalence from 3.3% in 2015 to 13.3% of all fixation constructs used for PDFF in 2019. NPC fixation is a recent development that been identified as an ideal treatment for osteoporotic distal femur fractures (both PDFF and NDFF) due to the balanced energy distribution between bone and implant [23]. It is of the authors’ opinion that the results reflect an increasing preference for this treatment by orthopedic surgeons at our institution to stabilize fractures in elderly patients with low bone density to facilitate earlier mobilization/weight bearing. We have identified a large NDFF population of middle-aged patients (average age=57 years old) with a balanced gender distribution. The most common fracture pattern consisted of metaphyseal comminution with intra-articular extension (AO/OTA 33C.2), suggesting a predominantly high-energy trauma mechanism. This contrasts with the findings of Roy et al., who reported a small sample of NDFF at a level-1 trauma center (n=87) consisting of mostly middle-aged female patients with comparable rates of high-energy (47%) and low-energy injuries (53%) [20]. These differences may be reflective of differences in the demographics of the catchment area that our institution serves. In contrast to prior literature, which reports coronal plane (AO/OTA 33B.3) fractures representing 38% of all partial articular (AO/OTA 33B) native fractures, our study reports an overall rate of 14% for 33B fractures with a majority being fractures of the lateral condyle (AO/OTA 33B.1) [24]. The mechanism of coronal plane fractures consists of vertical shear forces experienced during high-energy trauma, which is consistent with our NDFF population. The difference in our reported prevalence of 33B.3 fractures is less likely to be explained by low detection as CT scans were obtained for all patients. These demographic and injury severity differences may be reflective of population differences in sampling; however, we report an NDFF cohort that is much larger than the previously mentioned study, with greater potential for generalizability. With regards to the treatment of NDFF, rIMN was also the most common fixation used followed by lateral plating, which contrasts with previous studies which report plating as the most common fixation for NDFF [12], [13], [14]. Additionally, NPC was the third most common construct employed, which may be reflective of its increasing popularity as a treatment alternative for distal femur fractures as well as institutional preference for nailing. Quality of reduction was improved in the PDFF cohort compared to NDFF, based on normative values of alignment. This may be due to the simplicity of the fractures as PDFF were all type A fractures whereas NDFF commonly had intra-articular components. Additionally, the TKA implants force a certain nail start point given the box component with less variation so perhaps the nail is more on axis. However, nailing of these fractures has been previously associated with malalignment [25], [26]. Finally, the increase in NPC versus lateral plating alone may account for some of the differences as the tendency for malreduction with a single lateral locked plate is well documented [3]. We did not see any difference in nonunion, similar to prior studies but with an overall lower rate [25]. Contrary to our hypothesis, there were notable differences in outcomes between NDFF and PDFF. NDFF had significantly longer length of stays and were more likely to return to the operating room for additional treatment of the femur fracture compared to PDFF. The most common fracture pattern seen in NDFF undergoing reoperation was complete articular (AO/OTA 33C), and the most common etiology for UROR was for irrigation and debridement of the index fracture due to infection, reflective of the more severe soft tissue injury and propensity for open fractures. Upfill-Brown et al. previously conducted a large retrospective review which found no significant differences in 30-day reoperation rates between PDFF and NDFF [15]. However, their study did not account for mechanism or fracture complexity. The differences in length of stay and UROR rates among PDFF and NDFF noted in our study can be explained by the high prevalence of polytrauma, additional fractures, and increased fracture complexity (AO/OTA 33C) in the NDFF group. Additionally, Kaufman et al. studied outcomes in a matched cohort of PDFF and NDFF and found that when controlling for age, sex, and injury severity, there was no significant difference in length of stay or <90-day readmission rates between the two injuries [16]. The results of Kaufman et al. and our study support the notion that risk for readmission is more closely tied to population-specific risk factors such as demographics, mechanism, and additional injuries rather than the presence of periprosthetic fractures. There are several notable strengths to this study. This investigation encompasses recent patient data from a large population spanning 8 years followed longitudinally. Our study takes into consideration the quality of reduction when assessing outcomes for PDFF and NDFF. Limitations to the study include retrospective-single site sampling and an unmatched patient cohort. Our results reflect the treatment of distal femur fractures at a level-1 trauma center, and it is unclear whether similar results would be seen at a community hospital or arthroplasty surgical center. Finally, the addition of patient-reported outcomes would be beneficial but were not collected during the time frame investigated. Conclusion In conclusion, there exist differences in the patient demographics, fracture patterns, and fixation construct strategies of PDFF and NDFF patient populations. PDFF frequently occur as isolated, extra-articular, and comminuted injuries. Elderly women and those with poor bone quality are a high-risk group for PDFF. NDFF often occur in middle-aged individuals of both genders, often involving intra-articular extension and are frequently accompanied by additional orthopedic injuries. Patients with NDFF face an elevated risk of reoperation, particularly due to soft tissue complications. Finally, although rIMN was the common fixation strategy for both fracture categories, rates of NPC fixation for PDFF are increasing at our institution, whereas NDFF are still infrequently being treated with single lateral locked plate. Understanding these differences can guide future research to enhance treatment algorithms and implant designs specific to each population, ultimately improving patient outcomes. Declarations Conflicts of Interest: Authors SK, BB, MF, JK, KH, ST, AS, SS, MT, and EF have no disclosures. GS: DePuy, A Johnson & Johnson Company: Paid consultant, Orthopaedic Trauma Association: Board or committee member SC: AAOS: committee member, Synthes: paid consultant and paid travel, NSite Medical: stock, Takeda pharmaceuticals: research support ML: AO Foundation Board or committee member, Globus Medical: IP royalties, Osteocentric: Stock or stock Options, Osteocentric/SMV: Paid consultant, Synthes: Paid consultant; Paid presenter or speaker AMS: OTA: committee member; AAOS: committee member; ORS: committee member Source of Funding: None Acknowledgements: Abstract presented at: IOTA/OTA Triennial Meeting 2022, Amsterdam, NL ORS Annual Meeting 2023, Dallas, TX ICORS Meeting 2022, Edinburgh, UK References Fingar KR (Truven Health Analytics), Stocks C (AHRQ), Weiss AJ (Truven Health Analytics), Steiner CA (AHRQ). Most Frequent Operating Room Procedures Performed in U.S. Hospitals, 2003-2012. HCUP Statistical Brief #186. December 2014. 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Injury. 2021 Jul;52(7):1875-1879. doi: 10.1016/j.injury.2021.05.007. Epub 2021 May 12. PMID: 34030866. Campbell ST, Lim PK, Kantor AH, Gausden EB, Goodnough LH, Park AY. Complication Rates after Lateral Plate Fixation of Periprosthetic Distal Femur Fractures: A Multicenter Study. Injury. 2020 Aug;51(8):1858-1862. doi: 10.1016/j.injury.2020.05.009. Epub 2020 May 22. PMID: 32482424. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 18 Apr, 2024 Reviews received at journal 18 Apr, 2024 Reviewers agreed at journal 09 Apr, 2024 Reviewers agreed at journal 29 Mar, 2024 Reviewers invited by journal 12 Mar, 2024 Editor assigned by journal 12 Mar, 2024 Submission checks completed at journal 12 Mar, 2024 First submitted to journal 07 Mar, 2024 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-4032916","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":278801560,"identity":"4c971690-dd63-4b1a-b53c-797ccf20827c","order_by":0,"name":"Shana Kong","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Shana","middleName":"","lastName":"Kong","suffix":""},{"id":278801561,"identity":"c5f43d17-9790-495b-aa80-6243fb0bfa92","order_by":1,"name":"Barry Bautista","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Barry","middleName":"","lastName":"Bautista","suffix":""},{"id":278801562,"identity":"31dfc9d4-178f-4287-a64e-0931621edb5d","order_by":2,"name":"Max Haffner","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Max","middleName":"","lastName":"Haffner","suffix":""},{"id":278801563,"identity":"d653c30c-f796-48f7-b2c8-c83a0e5119c4","order_by":3,"name":"Judas Kelley","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Judas","middleName":"","lastName":"Kelley","suffix":""},{"id":278801564,"identity":"57820122-8462-4ec2-ac41-1e01d0641fac","order_by":4,"name":"Kelsey Hideshima","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Kelsey","middleName":"","lastName":"Hideshima","suffix":""},{"id":278801565,"identity":"14d18a8f-ad48-4508-ac71-7a7581651f36","order_by":5,"name":"Shannon Tse","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Shannon","middleName":"","lastName":"Tse","suffix":""},{"id":278801566,"identity":"70c13a9d-e2d4-4b74-81da-f243006fba8b","order_by":6,"name":"Aziz Saade","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Aziz","middleName":"","lastName":"Saade","suffix":""},{"id":278801567,"identity":"3496cfe9-73d4-478f-914c-9420257f2572","order_by":7,"name":"Samuel K. Simister","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Samuel","middleName":"K.","lastName":"Simister","suffix":""},{"id":278801568,"identity":"a022073b-5417-4c0b-a7b4-8df990cb1548","order_by":8,"name":"Megan Terle","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Megan","middleName":"","lastName":"Terle","suffix":""},{"id":278801569,"identity":"e3e202e8-a189-4b95-b1a8-8184bfcdaa36","order_by":9,"name":"Gillian Soles","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Gillian","middleName":"","lastName":"Soles","suffix":""},{"id":278801570,"identity":"a70aeebd-77b1-408c-8708-29de71f542d4","order_by":10,"name":"Sean T. Campbell","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Sean","middleName":"T.","lastName":"Campbell","suffix":""},{"id":278801571,"identity":"f74945a0-b6c4-4220-b25b-280bca25009d","order_by":11,"name":"Ellen Fitzpatrick","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Ellen","middleName":"","lastName":"Fitzpatrick","suffix":""},{"id":278801572,"identity":"7810f9c2-b1c7-4ad1-abf8-ab407f3240e4","order_by":12,"name":"Mark A. Lee","email":"","orcid":"","institution":"UC Davis Health System","correspondingAuthor":false,"prefix":"","firstName":"Mark","middleName":"A.","lastName":"Lee","suffix":""},{"id":278801573,"identity":"a2306c18-16bb-45d4-9093-ea5495d823e7","order_by":13,"name":"Augustine M. Saiz","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAz0lEQVRIie3OIQvCQBTA8ZdMMuszuH2FG4NhGH6WdwxcWfETaNrimui32EeYGFaGVuXKibBkECwLF5xiEtlpM9yfx6X34x2AyfSvEQTP9zEAxXdk+isB2MJr/wsyWJanq1R7nqVhjVKBbR2om6CIPaS+4Kuq9pEn4A11BEQMSCh4juQxvgCe64gjonNDbNeS6MZIwVxLmCAfiYqWxK6kHhDTEVfE/piK0FtVl5nkCbrrSnYTu/3YsVGTUZZG+aZRgWOVmivv4W/rJpPJZPrcHR3/TCec5jo5AAAAAElFTkSuQmCC","orcid":"","institution":"UC Davis Health System","correspondingAuthor":true,"prefix":"","firstName":"Augustine","middleName":"M.","lastName":"Saiz","suffix":""}],"badges":[],"createdAt":"2024-03-07 22:32:43","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4032916/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4032916/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":52711819,"identity":"49078b7b-77c8-49c0-b135-016ac7d82bc8","added_by":"auto","created_at":"2024-03-14 20:01:03","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":81223,"visible":true,"origin":"","legend":"\u003cp\u003ePre-operative and post-operative NDFF radiographs\u003c/p\u003e","description":"","filename":"DFFFigure1..png","url":"https://assets-eu.researchsquare.com/files/rs-4032916/v1/ce1e07d87a14ba3749ec8197.png"},{"id":52710643,"identity":"d9028154-d031-46fb-b283-a0b1d1581207","added_by":"auto","created_at":"2024-03-14 19:53:03","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":92012,"visible":true,"origin":"","legend":"\u003cp\u003ePre-operative and post-operative PDFF radiographs\u003c/p\u003e","description":"","filename":"DFFFigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4032916/v1/63f2948d8adfce16a66b811e.png"},{"id":52710646,"identity":"27d634f3-ff0e-45b1-a0f8-efd0e00680de","added_by":"auto","created_at":"2024-03-14 19:53:03","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":105479,"visible":true,"origin":"","legend":"\u003cp\u003eMeasurement of aLDFA on AP radiographs\u003c/p\u003e","description":"","filename":"DFFfigure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4032916/v1/2e5c207f6633dc5f6d12a42e.png"},{"id":52712298,"identity":"07e71574-b47a-4bce-b74f-cce4037e70a0","added_by":"auto","created_at":"2024-03-14 20:09:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":578769,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4032916/v1/568b472f-cec5-4e14-a6e9-cc8694844b87.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Clinical Differences Between Periprosthetic and Native Distal Femur Fractures","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIn 2012, total knee arthroplasty (TKA) was the single most common surgical procedure performed in the United States, with 94% of those procedures occurring in patients 65-84 years old [1], [2]. As the population ages and the prevalence of TKA rises, the frequency of periprosthetic distal femur fractures (PDFF) has simultaneously increased. Multiple studies report that distal femur fractures are the most common type of periprosthetic fracture occurring above a TKA\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[4], [5], [6]. Court-Brown et al. reported an increase in PDFF prevalence from 15.4% to 27.8% of all distal femur fractures from 2007-2011 [7]. Treatment of PDFF presents a challenge for orthopedic surgeons, who must not only take into consideration the complex and variable fracture morphology associated with the prosthesis but also the specific populations at risk.\u0026nbsp;\u003c/p\u003e\n\n\u003cp\u003ePrevious literature has focused on analyzing PDFF and native distal femur fractures (NDFF) separately. Roy et al. analyzed NDFF exclusively at a single level-1 trauma center and characterized the affected population as middle-aged, female (66%), and more often overweight than osteoporotic [8]. Additionally, they identified similar rates of high-and low-energy trauma in their NDFF cohort and found that high-energy type injuries were associated with more severe fracture types (AO/OTA 33B/C), open fractures, and additional orthopedic injuries, while low-energy injuries were associated with closed fractures and less severe fracture types (AO/OTA 33A)\u003csup\u003e\u0026nbsp;\u003c/sup\u003e[8]. Elsoe et al. first reported on the demographics of PDFF, noting a population distribution of elderly females (mean age=77) with low-energy injuries [9]. Regarding treatment, lateral plating and retrograde intramedullary nailing (rIMN) have been reported as the most common and successful fixations for both PDFF and NDFF, although intramedullary nail-plate combination (NPC) fixation has recently been developed as an additional treatment alternative [10], [11], [12] [13], [14]. Studies report similar 30-day and 90-day outcomes, though longer-term outcomes and reduction quality have yet to be studied [15], [16].\u003c/p\u003e\n\n\u003cp\u003eIn the existing body of literature, there is a notable lack of comprehensive comparisons between PDFF and NDFF within single institutions. Studies have focused exclusively on one fracture type without directly comparing it with the other. As a result, there is limited understanding of the relative differences between PDFF and NDFF in terms of demographics, fracture characteristics, treatment modalities, and outcomes.\u003c/p\u003e\n\n\u003cp\u003eTherefore, the primary objective of this study is to conduct a detailed comparison of PDFF and NDFF using data from a single large cohort within our institution. While there is some consistency in the literature regarding these fracture types, there remains a need to systematically examine and compare them within the same population to further denote remaining discrepancies which may arise from limited generalizability.\u0026nbsp;\u003c/p\u003e\n\n\u003cp\u003eFurthermore, a secondary aim is to explore aspects such as the quality of reduction and long-term outcomes, which have not been extensively studied in prior literature. These analyses are critical as they have the potential to provide valuable insights that can guide future treatment strategies and improve patient outcomes.\u0026nbsp;\u003c/p\u003e\n\n\u003cp\u003eWe hypothesize that PDFF are more likely to be isolated, simple, low-energy, injuries experienced by elderly patients while NDFF will be experienced by a younger population and result in more complicated fracture patterns due to higher levels of trauma.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFurthermore, we hypothesize there will be no difference in postoperative outcomes between PDFF and NDFF groups.\u0026nbsp;\u003c/p\u003e\n"},{"header":"Methods","content":"\u003cp\u003e\u003cem\u003eCohort Selection\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThis retrospective study was approved by the Institutional Review Board. \u0026nbsp;All patients who were at least 18 years of age at the time of admission with distal femur fractures between January 1\u003csup\u003est\u003c/sup\u003e, 2012 and December 31\u003csup\u003est\u003c/sup\u003e, 2020 at a single level-1 trauma center were identified. These patients were later classified as either NDFF or PDFF. Patients with bilateral distal femur fractures were not included.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eData Collection\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eElectronic medical records were used to obtain clinical data and demographics for each patient. American Society of Anesthesiologists (ASA) score and bone density status were obtained from clinical notes. Presence of bone loss, classified as either osteopenia or osteoporosis, was determined by either previous diagnosis documented in the patient chart or by comments noted by radiologists from existing radiographs. Fracture characteristics including AO/OTA fracture classifications were obtained from pre-operative radiographs and computed tomography (CT) scans. Polytrauma was noted if present and defined as having two or more injuries affecting two or more bodily areas. Type of surgical fixation was obtained from operative notes and radiographs. Patients with NPC fixation were categorized separately and did not contribute to nail or plate counts. Post-operative outcome data was obtained using follow-up notes and immediate post-operative radiographs.\u003c/p\u003e\n\u003cp\u003eQuality of reduction was assessed by calculating the difference in alignment from the population average anatomic lateral distal femoral angle (aLDFA) on post-operative anteroposterior (AP) radiographs. To measure the aLDFA (Figure 3), a line was first drawn parallel to both femoral condyles of the affected femur, representing the knee joint line. Next, a line was drawn from the center of the femoral head to the intercondylar notch of the affected femur, representing the mechanical axis of the femur. The lateral angle formed between the mechanical axis of the femur and the knee joint line was recorded in degrees as the aLDFA. The aLDFA for the contralateral, unaffected femur was also calculated if contralateral films had been acquired. The mean difference from the population average aLDFA of 81 degrees was calculated in the affected and unaffected femurs for both PDFF and NDFF groups. A smaller deviation from the population average aLDFA was accepted as a more desired outcome.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eStatistical Analyses\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eDifferences between PDFF and NDFF patients were compared using Fisher\u0026rsquo;s exact test, unpaired t-test, or multivariate analysis, as appropriate for each variable using Microsoft Excel. Multivariate analysis was completed in Excel using a linear regression with all variables included. Results were described using incidence rates, means, and one standard deviation. Statistical significance was assigned as p\u0026lt;0.05.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/122228_c8a1650c59388082/122228_custom_files/img1710414197.png\"\u003e\u003c/p\u003e\n\u003cp\u003eTable 1 summarizes the pre-operative characteristics of both cohorts. The mean age of NDFF patients was 23 years younger than the PDFF patients (p\u0026lt;0.001). There were significantly fewer females in the NDFF cohort (53% compared to 81%, p\u0026lt;0.001). The PDFF cohort had higher rates of bone loss (55.7% compared to 19.4%, p\u0026lt;0.001). There was no significant difference between ASA scores of both cohorts (p=0.061).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Fracture Characteristics of NDFF and PDFF patients\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eNDFF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003ePDFF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"50%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;AO/OTA classification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"50%\" colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e33A.2 Extra-articular Simple fracture\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e6%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e29%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e33A.3 Extra-articular Wedge or Multifragmentary Fracture\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e25%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e71%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e33C.1 Simple Articular, Simple metaphyseal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e6%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e0.215\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e33C.2 Simple Articular Wedge or Multifragmentary Metaphyseal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e28%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e33C.3 Multifragmentary Articular, Simple, Wedge or Multifragmentary metaphyseal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e22%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e33B.1 Partial Articular Lateral Condyle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e12%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.05\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e33B.3 Frontal/Coronal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e0.552\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003eIsolated Injury\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e51.8%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e80%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003ePolytrauma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e41%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e18.6%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003eOpen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e30.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e11.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.002\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003eComminution\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e85%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e92.1%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e0.274\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003eInterprosthetic Fracture\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e24.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"34.670947030497594%\" valign=\"top\"\u003e\n \u003cp\u003e\u003csup\u003ea\u0026nbsp;\u003c/sup\u003eFisher\u0026rsquo;s exact test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.261637239165328%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.224719101123597%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.84269662921348%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTable 2 summarizes the fracture characteristics of the two cohorts. 33A.2 and 33A.3 classifications represented the entirety of PDFF. In comparison, NDFF AO/OTA classifications were represented by 33C.2 (28%), 33C.3 (22%), and 33B.1 (12%), which were significantly more prevalent than in the PDFF cohort (p\u0026lt;0.001 for 33C.3 and 33C.3, and p\u0026lt;0.05 for 33B.1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 2 also shows significant differences in the rate of isolated injuries and polytraumas between both cohorts. PDFF were more often isolated injuries in patients (80% versus 51.8%, p\u0026lt;0.001). NDFF patients were more likely to be polytraumatized (41% compared to 18.6%, p\u0026lt;0.001). Additionally, NDFF patients also had higher rates of open fractures (30.7% compared to 11.2%, p=0.002). There was no significant difference between the comminution rates of fractures in both cohorts (p=0.274).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u003c/strong\u003e Surgical Fixation Construct Used in NDFF and PDFF patients\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eFixation Construct\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eNDFF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003ePDFF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eIntermedullary Nail\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e36.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e44.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0.297\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eNail Plate Combination\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e17.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e37.1%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.05\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eLateral Plate\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e20.8%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e14.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0.266\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eMedial Plate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e5.8%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0.053\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eLag Screws\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e6.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.05\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eOther\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e12.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e4.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003csup\u003ea\u0026nbsp;\u003c/sup\u003eFisher\u0026rsquo;s exact test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Table 3 summarizes the surgical fixation constructs used for both cohorts. Retrograde intermedullary nail was the most common fixation utilized in both groups, and there was no significant difference in the prevalence of rIMN between the two groups (NDFF = 36.7%, PDFF = 44.3%, p=0.297). NDFF patients had higher rates of medial plate usage (5.8% compared to 0%, p\u0026lt;0.05) and PDFF patients had higher rates of NPC used as fixation constructs (37.1% compared to 17.2%, p\u0026lt;0.05). Further analysis of NPC usage revealed usage beginning in 2015 for both groups, with prevalence of usage rising from 3.3% and 0.7% to 13.3% and 4.3% in 2019 (PDFF) and 2020 (NDFF) respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4.\u003c/strong\u003e Postoperative Outcomes of PDFF and NDFF patients\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eMeasure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eNDFF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003ePDFF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eAny Re-operation Occurrence\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e19 (13.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e6 (8.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.05\u003csup\u003ea\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eMalunion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 ( 0.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 (1.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eNonunion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e4 ( 2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e2 (2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eRevision\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 ( 0.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 (2.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eIrrigation and Debridement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e7 ( 5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eStiff Knee\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e2 (1.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003ePainful Orthopedic Hardware\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e2 (2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eRe-injury\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 ( 0.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eSeptic Arthritis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 ( 0.7% )\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eSkin Necrosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 (0.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eForeign Body Removal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1 (0.7% )\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e--\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eLength of Stay (days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e11.4 \u0026nbsp;\u0026plusmn; \u0026nbsp; \u0026nbsp; 16.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e6.36 \u0026plusmn; 5.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.05\u003csup\u003eb\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eLength of Follow-up (days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e148 \u0026plusmn; 181\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e164 \u0026plusmn; 204\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e0.564\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eDeviation of affected side from standard aLDFA (degrees)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e9.06 \u0026plusmn; 11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e3.04 \u0026plusmn; 2.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003csup\u003eb\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003eDeviation of contralateral side from standard aLDFA \u0026nbsp;(degrees)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e2.92 \u0026plusmn; 3.97\u003c/p\u003e\n \u003cp\u003e(n=9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e1.7 \u0026plusmn; 0\u003c/p\u003e\n \u003cp\u003e(n=1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003csup\u003e--\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003csup\u003ea\u0026nbsp;\u003c/sup\u003eMultivariate analysis\u003c/p\u003e\n \u003cp\u003e\u003csup\u003eb\u003c/sup\u003eUnpaired t-test\u003c/p\u003e\n \u003cp\u003e\u003csup\u003ec\u0026nbsp;\u003c/sup\u003eAnterior-Posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Post-operative outcomes are summarized in Table 4. Patients in the NDFF cohort had an approximately five-day longer length of stay compared to the PDFF cohort (p\u0026lt;0.05). There was no significant difference in length of follow-up between both cohorts (p=0.564). NDFF patients had higher rates of any unexpected return to the operating room (UROR) occurrences compared to their PDFF counterparts (13.6% compared to 8.5%, p\u0026lt;0.05). Out of the 19 NDFF requiring reoperation, 10 (52%) were AO/OTA type 33C fractures. Irrigation and debridement of the femur fracture of interest due to infection was the leading cause for UROR for NDFF patients (5% compared to 0%). The revision operation within the NDFF cohort was due to intra-articular prominence of an intramedullary nail, and the other revision within the PDFF cohort was due to implant failure with valgus angulation. PDFF patients had significantly improved quality of reduction with respect to the average population aLDFA of 81 degrees. The mean aLDFA in PDFF patients was approximately 6 degrees less in deviation compared to NDFF patients (p\u0026lt;0.001). In addition, when using the non-injured contralateral aLDFA, PDFF were approximately 1.2 degrees less in deviation. However, significance could not be gathered given the limited availability of contralateral imaging.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study is the first to directly compare native and periprosthetic distal femur fractures. PDFF were found to be commonly isolated injuries with complete metaphyseal comminution, affecting elderly women and those with low bone quality. NDFF, on the other hand, tended to occur in younger patients with less metaphyseal comminution and additional fractures. The study highlighted that the NDFF group had increased revision reoperation rates compared to PDFF, specifically for irrigation and debridement of the femur fracture of interest. Multivariate regress analysis revealed that NDFF are an independent risk factor for reoperation, specifically irrigation and debridement of the fracture of interest, compared to PDFF.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe present study reports a PDFF gender distribution similar to Elsoe et al., who documented a sample of mostly females with a mean age of 77 years old [17]. Additionally, our PDFF sample was characterized by a high prevalence of low bone density. Low bone density has been highlighted as a risk factor for femur fractures in past studies, and low-energy distal femur fractures are now considered fragility fractures [7], [18]. This study reports the exact rate of low bone density (osteopenia or osteoporosis) in our PDFF population. Although trauma mechanisms were not formally investigated in our study, we saw that PDFF were mostly isolated injuries, which is more suggestive of a low-energy trauma mechanism as proposed by prior studies [19], [20].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;The most common fracture pattern for PDFF was extraarticular with complete metaphyseal comminution (AO/OTA 33A.3). The increased metaphyseal comminution is likely related to both the presence of low bone quality and the TKA affecting the stress concentration locations of the fracture. Low bone quality leads to an overall decreased tolerance for withstanding forces. Additionally, with the TKA present, the fracture cannot propagate into the joint, and more energy may be imparted to the metaphysis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;While previous studies have documented rIMN and lateral locked plating as the most common method of treatment for PDFF, our study has identified rIMN and NPC fixation to be the most common methods utilized at our institution [11], [21], [22]. Further analysis of NPC fixation rates revealed an increase in prevalence from 3.3% in 2015 to 13.3% of all fixation constructs used for PDFF in 2019. NPC fixation is a recent development that been identified as an ideal treatment for osteoporotic distal femur fractures (both PDFF and NDFF) due to the balanced energy distribution between bone and implant [23]. It is of the authors\u0026rsquo; opinion that the results reflect an increasing preference for this treatment by orthopedic surgeons at our institution to stabilize fractures in elderly patients with low bone density to facilitate earlier mobilization/weight bearing.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;We have identified a large NDFF population of middle-aged patients (average age=57 years old) with a balanced gender distribution. The most common fracture pattern consisted of metaphyseal comminution with intra-articular extension (AO/OTA 33C.2), suggesting a predominantly high-energy trauma mechanism. This contrasts with the findings of Roy et al., who reported a small sample of NDFF at a level-1 trauma center (n=87) consisting of mostly middle-aged female patients with comparable rates of high-energy (47%) and low-energy injuries (53%) [20]. These differences may be reflective of differences in the demographics of the catchment area that our institution serves. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;In contrast to prior literature, which reports coronal plane (AO/OTA 33B.3) fractures representing 38% of all partial articular (AO/OTA 33B) native fractures, our study reports an overall rate of 14% for 33B fractures with a majority being fractures of the lateral condyle (AO/OTA 33B.1) [24]. The mechanism of coronal plane fractures consists of vertical shear forces experienced during high-energy trauma, which is consistent with our NDFF population. The difference in our reported prevalence of 33B.3 fractures is less likely to be explained by low detection as CT scans were obtained for all patients. These demographic and injury severity differences may be reflective of population differences in sampling; however, we report an NDFF cohort that is much larger than the previously mentioned study, with greater potential for generalizability.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;With regards to the treatment of NDFF, rIMN was also the most common fixation used followed by lateral plating, which contrasts with previous studies which report plating as the most common fixation for NDFF [12], [13], [14]. Additionally, NPC was the third most common construct employed, which may be reflective of its increasing popularity as a treatment alternative for distal femur fractures as well as institutional preference for nailing.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Quality of reduction was improved in the PDFF cohort compared to NDFF, based on normative values of alignment. This may be due to the simplicity of the fractures as PDFF were all type A fractures whereas NDFF commonly had intra-articular components. Additionally, the TKA implants force a certain nail start point given the box component with less variation so perhaps the nail is more on axis. However, nailing of these fractures has been previously associated with malalignment [25], [26]. Finally, the increase in NPC versus lateral plating alone may account for some of the differences as the tendency for malreduction with a single lateral locked plate is well documented [3]. We did not see any difference in nonunion, similar to prior studies but with an overall lower rate [25].\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;Contrary to our hypothesis, there were notable differences in outcomes between NDFF and PDFF. NDFF had significantly longer length of stays and were more likely to return to the operating room for additional treatment of the femur fracture compared to PDFF. The most common fracture pattern seen in NDFF undergoing reoperation was complete articular (AO/OTA 33C), and the most common etiology for UROR was for irrigation and debridement of the index fracture due to infection, reflective of the more severe soft tissue injury and propensity for open fractures. Upfill-Brown et al. previously conducted a large retrospective review which found no significant differences in 30-day reoperation rates between PDFF and NDFF [15]. However, their study did not account for mechanism or fracture complexity. The differences in length of stay and UROR rates among PDFF and NDFF noted in our study can be explained by the high prevalence of polytrauma, additional fractures, and increased fracture complexity (AO/OTA 33C) in the NDFF group. Additionally, Kaufman et al. studied outcomes in a matched cohort of PDFF and NDFF and found that when controlling for age, sex, and injury severity, there was no significant difference in length of stay or \u0026lt;90-day readmission rates between the two injuries [16]. The results of Kaufman et al. and our study support the notion that risk for readmission is more closely tied to population-specific risk factors such as demographics, mechanism, and additional injuries rather than the presence of periprosthetic fractures.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;There are several notable strengths to this study. This investigation encompasses recent patient data from a large population spanning 8 years followed longitudinally. Our study takes into consideration the quality of reduction when assessing outcomes for PDFF and NDFF. Limitations to the study include retrospective-single site sampling and an unmatched patient cohort. Our results reflect the treatment of distal femur fractures at a level-1 trauma center, and it is unclear whether similar results would be seen at a community hospital or arthroplasty surgical center. Finally, the addition of patient-reported outcomes would be beneficial but were not collected during the time frame investigated.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, there exist differences in the patient demographics, fracture patterns, and fixation construct strategies of PDFF and NDFF patient populations. PDFF frequently occur as isolated, extra-articular, and comminuted injuries. Elderly women and those with poor bone quality are a high-risk group for PDFF. NDFF often occur in middle-aged individuals of both genders, often involving intra-articular extension and are frequently accompanied by additional orthopedic injuries. Patients with NDFF face an elevated risk of reoperation, particularly due to soft tissue complications. Finally, although rIMN was the common fixation strategy for both fracture categories, rates of NPC fixation for PDFF are increasing at our institution, whereas NDFF are still infrequently being treated with single lateral locked plate. Understanding these differences can guide future research to enhance treatment algorithms and implant designs specific to each population, ultimately improving patient outcomes.\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflicts of Interest:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAuthors SK, BB, MF, JK, KH, ST, AS, SS, MT, and EF have no disclosures.\u003c/p\u003e\n\u003cp\u003eGS: DePuy, A Johnson \u0026amp; Johnson Company: Paid consultant, Orthopaedic Trauma Association: Board or committee member\u003c/p\u003e\n\u003cp\u003eSC: AAOS: committee member, Synthes: paid consultant and paid travel, NSite Medical: stock, Takeda pharmaceuticals: research support\u003c/p\u003e\n\u003cp\u003eML: AO Foundation Board or committee member, Globus Medical: IP royalties, Osteocentric: Stock or stock Options, Osteocentric/SMV: Paid consultant, Synthes: Paid consultant; Paid presenter or speaker\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAMS: OTA: committee member; AAOS: committee member; ORS: committee member\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eSource of Funding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eAcknowledgements:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAbstract presented at:\u003c/p\u003e\n\u003cp\u003eIOTA/OTA Triennial Meeting 2022, Amsterdam, NL\u003c/p\u003e\n\u003cp\u003eORS Annual Meeting 2023, Dallas, TX\u003c/p\u003e\n\u003cp\u003eICORS Meeting 2022, Edinburgh, UK\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eFingar KR (Truven Health Analytics), Stocks C (AHRQ), Weiss AJ (Truven Health Analytics), Steiner CA (AHRQ). Most Frequent Operating Room Procedures Performed in U.S. Hospitals, 2003-2012. HCUP Statistical Brief #186. December 2014. Agency for Healthcare Research and Quality, Rockville, MD. http://www.hcup-us.ahrq.gov/reports/statbriefs/sb186-Operating-Room-Procedures-United-States-2012.pdf.\u003c/li\u003e\n \u003cli\u003eBenkovich V, Klassov Y, Mazilis B, Bloom S. Periprosthetic fractures of the knee: a comprehensive review. Eur J Orthop Surg Traumatol. 2020 Apr;30(3):387-399. doi: 10.1007/s00590-019-02582-5. Epub 2019 Nov 19. PMID: 31745642; PMCID: PMC7138771.\u003c/li\u003e\n \u003cli\u003eChandra Vemulapalli K, Pechero GR, Warner SJ, Achor TS, Gary JL, Munz JW, Choo AM, Prasarn ML, Chip Routt ML Jr. Is retrograde nailing superior to lateral locked plating for complete articular distal femur fractures? Injury. 2022 Feb;53(2):640-644. doi: 10.1016/j.injury.2021.11.037. Epub 2021 Nov 23. PMID: 34863509.\u003c/li\u003e\n \u003cli\u003eWelch T, Iorio R, Marcantonio AJ, Kain MS, Tilzey JF, Specht LM, Healy WL. Incidence of Distal Femoral Periprosthetic Fractures after Total Knee Arthroplasty. Bull Hosp Jt Dis (2013). 2016 Nov;74(4):287-292. PMID: 27815952.\u003c/li\u003e\n \u003cli\u003eRorabeck CH, Taylor JW. Periprosthetic fractures of the femur complicating total knee arthroplasty. Orthop Clin North Am. 1999 Apr;30(2):265-77. doi: 10.1016/s0030-5898(05)70081-x. PMID: 10196428.\u003c/li\u003e\n \u003cli\u003eBerry DJ. Epidemiology: hip and knee. Orthop Clin North Am. 1999 Apr;30(2):183-90. doi: 10.1016/s0030-5898(05)70073-0. PMID: 10196420.\u003c/li\u003e\n \u003cli\u003eCourt-Brown CM, Caesar B. Epidemiology of adult fractures: A review. Injury. 2006 Aug;37(8):691-7. doi: 10.1016/j.injury.2006.04.130. Epub 2006 Jun 30. PMID: 16814787.\u003c/li\u003e\n \u003cli\u003eRoy D, Ramski D, Malige A, Beck M, Jeffers K, Brogle P. Injury patterns and outcomes associated with fractures of the native distal femur in adults. Eur J Trauma Emerg Surg. 2021 Aug;47(4):1123-1128. doi: 10.1007/s00068-019-01287-y. Epub 2019 Dec 23. PMID: 31872341.\u003c/li\u003e\n \u003cli\u003eElsoe R, Ceccotti AA, Larsen P. Population-based epidemiology and incidence of distal femur fractures. Int Orthop. 2018 Jan;42(1):191-196. doi: 10.1007/s00264-017-3665-1. Epub 2017 Nov 7. PMID: 29116356.\u003c/li\u003e\n \u003cli\u003eRistevski B, Nauth A, Williams DS, Hall JA, Whelan DB, Bhandari M. Systematic review of the treatment of periprosthetic distal femur fractures. J Orthop Trauma. 2014 May;28(5):307-12. doi: 10.1097/BOT.0000000000000002. PMID: 24149447.\u003c/li\u003e\n \u003cli\u003eEbraheim NA, Kelley LH, Liu X, Thomas IS, Steiner RB, Liu J. Periprosthetic Distal Femur Fracture after Total Knee Arthroplasty: A Systematic Review. Orthop Surg. 2015 Nov;7(4):297-305. doi: 10.1111/os.12199. PMID: 26790831; PMCID: PMC6583744.\u003c/li\u003e\n \u003cli\u003eTahami M, Vaziri AS, Tahmasebi MN, Vosoughi F, Khalilizad M, Shakiba S. Practical approach to the native distal femur fractures in the elderly: A rapid review over the recent trends. Injury. 2022 Jul;53(7):2389-2394. doi: 10.1016/j.injury.2022.05.014. Epub 2022 May 19. PMID: 35644641.\u003c/li\u003e\n \u003cli\u003eKoso RE, Terhoeve C, Steen RG, Zura R. Healing, nonunion, and re-operation after internal fixation of diaphyseal and distal femoral fractures: a systematic review and meta-analysis. Int Orthop. 2018 Nov;42(11):2675-2683. doi: 10.1007/s00264-018-3864-4. Epub 2018 Mar 8. PMID: 29516238.\u003c/li\u003e\n \u003cli\u003eRoy D, Ramski D, Malige A, Beck M, Jeffers K, Brogle P. Injury patterns and outcomes associated with fractures of the native distal femur in adults. Eur J Trauma Emerg Surg. 2021 Aug;47(4):1123-1128. doi: 10.1007/s00068-019-01287-y. Epub 2019 Dec 23. PMID: 31872341.\u003c/li\u003e\n \u003cli\u003eUpfill-Brown A, Arshi A, Sekimura T, Lee C, Stavrakis A, Sassoon A. Short-term outcomes of periprosthetic compared to native distal femur fractures, a national database study. Arch Orthop Trauma Surg. 2021 Jun 29. doi: 10.1007/s00402-021-04000-0. Epub ahead of print. PMID: 34185154.\u003c/li\u003e\n \u003cli\u003eKaufman MW, Rascoe AS, Hii JL, Thom ML, Levine AD, Wilber RG. Comparable Outcomes Between Native and Periprosthetic Fractures of the Distal Femur. J Knee Surg. 2022 Jul 12. doi: 10.1055/s-0042-1749604. Epub ahead of print. PMID: 35820430.\u003c/li\u003e\n \u003cli\u003eElsoe R, Ceccotti AA, Larsen P. Population-based epidemiology and incidence of distal femur fractures. Int Orthop. 2018 Jan;42(1):191-196. doi: 10.1007/s00264-017-3665-1. Epub 2017 Nov 7. PMID: 29116356.\u003c/li\u003e\n \u003cli\u003eNg AC, Drake MT, Clarke BL, Sems SA, Atkinson EJ, Achenbach SJ,. Trends in subtrochanteric, diaphyseal, and distal femur fractures, 1984-2007. Osteoporos Int. 2012 Jun;23(6):1721-6. doi: 10.1007/s00198-011-1777-9. Epub 2011 Sep 10. PMID: 21909727; PMCID: PMC3266989.\u003c/li\u003e\n \u003cli\u003ePietu G, Lebaron M, Flecher X, Hulet C, Vandenbussche E; SOFCOT. Epidemiology of distal femur fractures in France in 2011-12. Orthop Traumatol Surg Res. 2014 Sep;100(5):545-8. doi: 10.1016/j.otsr.2014.06.004. Epub 2014 Aug 22. PMID: 25155091.\u003c/li\u003e\n \u003cli\u003eRoy D, Ramski D, Malige A, Beck M, Jeffers K, Brogle P. Injury patterns and outcomes associated with fractures of the native distal femur in adults. Eur J Trauma Emerg Surg. 2021 Aug;47(4):1123-1128. doi: 10.1007/s00068-019-01287-y. Epub 2019 Dec 23. PMID: 31872341.\u003c/li\u003e\n \u003cli\u003eLombardo, D.J., Siljander, M.P., Sobh, A. \u003cem\u003eet al.\u003c/em\u003e Periprosthetic fractures about total knee arthroplasty. \u003cem\u003eMusculoskelet Surg\u003c/em\u003e 104, 135\u0026ndash;143 (2020). https://doi.org/10.1007/s12306-019-00628-9\u003c/li\u003e\n \u003cli\u003eNauth A, Ristevski B, B\u0026eacute;gu\u0026eacute; T, Schemitsch EH. Periprosthetic distal femur fractures: current concepts. J Orthop Trauma. 2011 Jun;25 Suppl 2:S82-5. doi: 10.1097/BOT.0b013e31821b8a09. PMID: 21566481.\u003c/li\u003e\n \u003cli\u003eLiporace FA, Yoon RS. Nail Plate Combination Technique for Native and Periprosthetic Distal Femur Fractures. J Orthop Trauma. 2019 Feb;33(2):e64-e68. doi: 10.1097/BOT.0000000000001332. PMID: 30277982.\u003c/li\u003e\n \u003cli\u003eNork SE, Segina DN, Aflatoon K, Barei DP, Henley MB, Holt S. The association between supracondylar-intercondylar distal femoral fractures and coronal plane fractures. The Journal of Bone \u0026amp; Joint Surgery 87(3):p 564-569, March 2005. | DOI: 10.2106/JBJS.D.01751\u003c/li\u003e\n \u003cli\u003eGausden EB, Lim PK, Rabonivich A, Shaath MK, Mitchell PM, Hartline B. Outcomes of periprosthetic distal femur fractures following total knee arthroplasty: Intramedullary nailing versus plating. Injury. 2021 Jul;52(7):1875-1879. doi: 10.1016/j.injury.2021.05.007. Epub 2021 May 12. PMID: 34030866.\u003c/li\u003e\n \u003cli\u003eCampbell ST, Lim PK, Kantor AH, Gausden EB, Goodnough LH, Park AY. Complication Rates after Lateral Plate Fixation of Periprosthetic Distal Femur Fractures: A Multicenter Study. Injury. 2020 Aug;51(8):1858-1862. doi: 10.1016/j.injury.2020.05.009. Epub 2020 May 22. PMID: 32482424.\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":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4032916/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4032916/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePeriprosthetic distal femur fractures (PDFF) are becoming more prevalent as total knee replacements become more common. This study compares the demographics, fracture characteristics, treatment, and outcomes of periprosthetic versus native distal femur fractures (NDFF).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials and Methods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is a retrospective cohort study of patients ≥ 18 who underwent surgical fixation of NDFF or PDFF from 2012-2020 at a level-1 trauma center. Primary outcomes included demographics, AO/OTA fracture classification, fixation construct, and unexpected return to the operating room (UROR). Secondary outcomes were concomitant fractures, polytrauma rates, low bone density, and reduction quality. T-test, Fisher’s exact test, and multivariable analysis were used for statistical analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e209 patients were identified, including 70 PDFF and 139 NDFF. PDFF patients were elderly females (81%) with isolated (80%) and comminuted (85%) 33A.3 (71%) fractures. NDFF patients included 53% females, were commonly middle-aged, and displayed comminuted (92%) 33C.2 fractures. 48% of NDFF patients had concomitant fractures. Intramedullary nailing was the primary fixation for both groups, followed by nail-plate combination (37%) for PDFF and lateral locking plates (21%) for NDFF. NDFF patients experienced lengthier hospital stays and higher UROR rates (p\u0026lt;0.05). PDFF patients had a significantly higher prevalence of low bone density (p\u0026lt;0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePDFF occur as isolated injuries with significant metaphyseal comminution in elderly females with low bone quality. NDFF commonly occurs in younger patients with less metaphyseal comminution and concomitant fractures. Intramedullary nailing was the most common treatment for both groups, though preference for nail-plate combination fixation is increasing. NDFF type 33C fractures are at higher risk of UROR.\u003c/p\u003e","manuscriptTitle":"Clinical Differences Between Periprosthetic and Native Distal Femur Fractures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-14 19:52:58","doi":"10.21203/rs.3.rs-4032916/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-04-18T12:25:27+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-04-18T10:58:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"9542bbe4-3a4e-490a-b092-a66aba39faa3","date":"2024-04-09T05:44:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"7818d583-1cb3-40c3-aa3c-40b8f61878ab","date":"2024-03-29T07:37:40+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-03-12T06:11:11+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-03-12T06:09:00+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-03-12T05:55:22+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Orthopaedic Surgery and Research","date":"2024-03-07T22:25:42+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3d1f14ab-9177-458b-9fa5-015d8f64296f","owner":[],"postedDate":"March 14th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2024-05-14T07:59:37+00:00","versionOfRecord":[],"versionCreatedAt":"2024-03-14 19:52:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4032916","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4032916","identity":"rs-4032916","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}