Does matching degree matter for proximal femoral intramedullary nail on reoperation rate in intertrochanteric fractures?

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Fei Wang, Ji-Long Zou, Jian Shang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1914789/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 29 Dec, 2022 Read the published version in Journal of Orthopaedic Surgery and Research → Version 1 posted 8 You are reading this latest preprint version Abstract Introduction Previous articles reported on the tip-apex distance, lag screw placement, fracture pattern, reduction quality, osteoporosis and other factors associated with second surgery. The current study focused on investigating the association of the matching degree between proximal femoral intramedullary nail and femoral medullary cavity on reoperation rate. Patients and methods A retrospective cohort study was conducted. It included patients with intertrochanteric fracture who were treated with proximal femoral anti-rotatory intramedullary nail (PFNA) between January 2016 and April 2021. The gap between the intramedullary nail and the femoral medullary cavity was equal to the difference in diameter between the two. According to the gap size, all patients were divided into three groups, as follows: high-matching group: gap ≤ 2 mm; middle-matching group: 2 < gap < 4 mm; and low-matching group: gap ≥ 4 mm. The mean gap was measured through standard images. The primary observational index was whether the reoperation was needed, and secondary observational indexes included operative time, length of hospital stay. Patient characteristics were recorded, as follows: age, sex, follow-up time, fracture pattern, reduction grade and length of intramedullary nail. Results A total of 203 eligible patients were recorded, including 78 males (38.4%) and 125 females (61.6%). They had a mean age of 77.8 ± 9.9 years old and an average follow-up time of 58.1 ± 24.0 weeks. Twenty-seven patients (13.3%) needed a second operation. Coxa varus combined with screw cutting was the most common reason for reoperation (11 cases). Unstable fracture pattern with poor reduction grade tended to contribute to reoperation, whose odds ratio (OR) was 6.61 (95% confidence interval [CI], 1.98–22.09; p = 0.002). The three groups had 11 cases (13.7%), 12 cases (13.8%) and 4 cases (11.1%) of reoperation respectively and logistic regression showed no significant association was noted between matching degree of intramedullary nail and reoperation rate. Conclusions The matching degree between proximal femoral intramedullary nail and femoral medullary cavity did not seem to be an important factor for reoperation, which offered more options of intramedullary nail size intraoperatively and reduced implants stock from inventory. Intertrochanteric fracture Matching degree Gap Reoperation Figures Figure 1 Figure 2 Introduction Intertrochanteric fracture occurs in elderly commonly, and most patients lose part of the hip function, which brings great burden to their families and constitutes a large part of the healthcare burden[ 1 , 2 ]. Intramedullary nailing has become a common treatment for intertrochanteric fracture. It is applied to various types of fracture with a good biomechanical performance. Intramedullary nailing allows patients to walk immediately after surgery[ 3 , 4 ]. But implant failures are often reported. Previous studies have reported the failure patterns of internal fixation, including coxa varus, screw cutting, screw backing-out, prosthesis peripheral fracture and non-union[ 5 – 7 ]. Some studies forecasted the risk factors of implant failures, such as the tip-apex distance, lag screw placement, fracture pattern, reduction grade and osteoporosis[ 8 – 13 ]. However, few studies were related to the effect of the matching degree between proximal femoral intramedullary nail and femoral medullary cavity on reoperation rate. The current study focuses on this effect to serve as a guide for choosing the size of nail intraoperatively. Patients And Methods After obtaining the approval of the Ethics Committee of the First Affiliated Hospital of Harbin Medical University, a retrospective cohort study was conducted on patients with intertrochanteric fracture who were treated with proximal femoral anti-rotatory intramedullary nail (PFNA) between January 2016 and April 2021. Inclusion criteria included patients who were older than 60 years old and followed up for at least 24 weeks. Exclusion criteria included patients who had tumour-induced fracture, had serious medical disease and had to undergo long-term bed rest, had postoperative cognitive impairment and were unable to provide complete radiological image. The primary observational index was whether the reoperation was needed, and secondary observational indexes included operative time, length of hospital stay. Patient characteristics were recorded, as follows: age, sex, follow-up time, fracture pattern, reduction grade and length of intramedullary nail. The causes of reoperation were recorded, including coxa varus, screw cutting (extrusion with no cranial perforation), screw cutting-out (a cranial perforation), screw backing-out, prosthesis peripheral fracture, non-union and complications associated with internal fixation. Fractures were classified according to OTA/AO classification[ 14 ]. OTA/AO 31A1 fractures were defined as stable fractures, and 31A2 and 31A3 fractures were defined as unstable fractures[ 15 ]. According to the experience of Baumgaertner et al, the standard reduction was defined as follows. 1. The distance of the fracture fragment was ༜4 mm on standard anteroposterior and lateral radiographs. 2. The neck-shaft angle on AP view was normal or slightly valved (130°–150°), and the angulation of fracture fragment was ༜20 ° on Lat view. If both criteria were met, then the reduction quality was classified as good. If one criterion was met, then the reduction quality was classified as acceptable. If neither criteria was met, then it was classified as poor[ 16 ]. There were three types of intramedullary nail lengths used, namely, 170, 200 and 240 mm. Only one distal static locking bolt was secured to the intramedullary nail due to the habit of the surgeon. To evaluate whether patients have achieved bone union, three criteria must be met, as follows: 1. at least three cortices showing continuous callus formation on standard anteroposterior and lateral radiographs; 2. absence of obvious pain on palpation and percussion at original fracture site; and 3. ability to walk without auxiliary devices[ 17 , 18 ]. The length and diameter of the intramedullary nail can be obtained from the surgical record. Considering that the diameter of femoral medullary cavity was not uniform, the diameter was measured at the level where the medullary cavity is most fully filled with distal nail by ImedPacs software system (Dong Hua Software Company, China) (Fig. 2 ). The gap between the intramedullary nail and the femoral medullary cavity was equal to the difference in diameter between the two, and all patients were divided into three groups according to the gap: high-matching group: gap ≤ 2 mm; middle-matching group: 2 < gap < 4 mm; and low-matching group: gap ≥ 4 mm. The grouping method was based on the experience of Richard et al[ 19 ] and the actual situation of this cohort study. Statistical analysis: The statistical analysis was performed using R version 4.0.3. A Chi-Square Test was used to compare homogeneous distribution among categorical variables by evaluating frequencies within the groups. A one-way analysis of variance (ANOVA) test was used for comparing homogeneous distribution among numerical variables. Logistic regression was performed to analyze the relationships of reoperation with age, sex, fracture pattern and reduction quality, nail length and matching degree. Result A total of 203 patients were finally enrolled (Table 1). Eighty patients were in high-matching group (gap ≤ 2 mm), 87 cases were in middle-matching group ( 2 mm < gap ༜ 4 mm) and 36 patients were in low-matching group (gap ≥ 4 mm). There were 78 males (38.4%) and 125 females (61.6%). The mean age of the patients was 77.8 ± 9.9 years old, and the mean follow-up time was 58.1 ± 24.0 weeks. Forty-eight cases were considered as stable fracture (23.6%), and 155 cases were considered as unstable fracture (76.4%). The cases with good, acceptable and poor fracture reduction grades were 103 (50.7%), 67 (33.0%) and 33 (16.3%), respectively. Twenty-seven patients (13.3%) required additional surgery. The most common cause of reoperation is coxa varus combined with cutting of screw (11 cases). Other causes of reoperation include coxa varus combined with cutting-out of screw (two cases), coxa varus combined with back nail (three cases), simple coxa varus (two cases); non-union (four cases), pain associated with intramedullary nail stimulation (five cases). The three groups had 11 cases (13.7%), 12 cases (13.8%) and 4 cases (11.1%) of reoperation respectively, and no statistically significant difference was found among the groups (P = 0.925). Statistically significant differences were not observed among the three groups in age, gender, follow-up time, length of hospital stay, fracture patterns and reduction quality, as shown in Table 2 . However, a significant difference was found in the length of intramedullary nail (P = 0.049). The differences of operative time among the three groups were also analyzed, and significant differences were not observed (P = 0.071, 0.681, 0.767). Logistic regression analysis was conducted (Table 3 ). Age, sex, nail length and gap size were not significant. Therefore, no significant association were found among them and reoperation. No strong dependency was observed among explanatory variables, except between reduction quality and fracture pattern (6.798e-13). Therefore, these two variables were combined together to one categorical variable with five levels (Stable, good; Stable, acceptable; Unstable, good; Unstable, acceptable and Unstable, poor). Unstable fracture pattern with poor reduction grade tended to contribute to reoperation, whose odds ratio (OR) was 6.61 (95% confidence interval [CI], 1.98–22.09; p = 0.002). Result showed matching degree was not a important factor of reoperation. Table 1 Characteristics of intertrochanteric fractures in three groups. Characteristic High matching group Middle matching group Low matching group Combination Patient, n (%) 80 (39.4%) 87 (42.9%) 36 (17.7%) 203 (100%) Age, mean± SD (Year) 76.6±10.7 78.8±9.3 78.1±9.8 77.8±9.9 Gender, n (%) Male 37 (46.3%) 32 (36.8%) 9 (25.0%) 78 (38.4%) Female 43 (53.7%) 55 (63.2%) 27 (75.0%) 125 (61.6%) Follow-up Time, mean± SD (Week) 58.8±23.9 58.9±24.1 54.7±24.7 58.1±24.0 Length of Stay, mean± SD (Day) 9.8±4.3 9.3±4.0 8.6±3.6 9.4±4.1 Operating Time, mean± SD (Minute) 120.7±43.2 107.7±35.2 121.2±43.4 115.2±40.3 Fracture, n (%) Stable 21 (26.3%) 19 (21.8%) 8 (22.2%) 48 (23.6%) Unstable 59 (73.7%) 68 (78.2%) 28 (77.8%) 155 (76.4%) Quality of Reduction, n (%) Good 41 (51.2%) 43 (49.4%) 19 (52.8%) 103 (50.7%) Acceptable 26 (32.5%) 33 (37.9%) 8 (22.2%) 67 (33.0%) Poor 13 (16.3%) 11 (12.7%) 9 (25.0%) 33 (16.3%) Nail Type, n (%) 170mm 27 (33.7%) 20 (23.0%) 9 (25.0%) 56 (27.6%) 200mm 45 (56.3%) 64 (73.6%) 27 (75.0%) 136 (67.0%) 240mm 8 (10.0%) 3 (3.4%) 0 (0%) 11 (5.4%) Postoperative outcome, n (%) Non-reoperation 69 (86.3%) 75 (86.2%) 32 (88.9%) 176 (86.7%) Reoperation 11 (13.7%) 12 (13.8%) 4 (11.1%) 27 (13.3%) Table 2 Statistically correlated results of three groups Characteristic High matching group Middle matching group Low matching group P -value Age, mean± SD (Year) 76.6±10.7 78.8±9.3 78.1±9.8 0.352 Female Gender, n (%) 43 (53.7%) 55 (63.2%) 27 (75.0%) 0.086 Follow-up Time, mean± SD (Week) 58.8±23.9 58.9±24.1 54.7±24.7 0.642 Length of Stay, mean± SD (Day) 9.8±4.3 9.3±4.0 8.6±3.6 0.342 Operating Time, mean± SD (Minute) 120.7±43.2 107.7±35.2 121.2±43.4 0.071 Unstable Fracture pattern, n (%) 59 (73.7%) 68 (78.2%) 28 (77.8%) 0.779 Poor reduction grade, n (%) 13 (16.3%) 11 (12.7%) 9 (25.0%) 0.358 240mm Nail, n (%) 8 (10.0%) 3 (3.4%) 0 (0%) 0.049 Reoperation, n (%) 11 (13.7%) 12 (13.8%) 4 (11.1%) 0.925 Table 3 . Logistic Regression Analysis Regression Odds Ratio 95% Confidence P- Model Ratio Interval value Age 1.01 0.96-1.05 0.811 Gender Male 0.42 0.15-1.20 0.106 Female Ref Ref Ref Fracture pattern and reduction grade Stable, good 0.19 0.02-1.62 0.129 Stable, acceptable 1.14 0.12-11.19 0.909 Unstable, good 0.77 0.22-2.67 0.683 Unstable, acceptable Ref Ref Ref Unstable, poor 6.61 1.98-22.09 0.002 Nail Length 170mm Ref Ref Ref 200mm 1.21 0.39-3.77 0.739 240mm 2.63 0.45-15.41 0.284 Matching degree High matching degree Ref Ref Ref Middle matching degree 2.43 0.58-10.23 0.225 Low matching degree 2.22 0.50-9.94 0.295 Discussion The matching degree between the nail and femoral medullary cavity might affect fracture healing[ 20 ]. Millar et al.’s study of femoral shaft fractures asserted that a satisfactory nail fit allows smaller interfragmentary movement, which results in a more satisfactory outcome; they recommended an ideal nail fit of 90% at the isthmus to avoid surgical re-intervention[ 20 ]. However, the biomechanics of intertrochanteric fractures are different from those of femoral shaft fractures. Studies describing matching rate as an indicator of fracture healing and stability for intertrochanteric fractures are few. Some scholars have compared the effect of the matching degree of intramedullary nail on stability from the perspective of biomechanics. Simpson et al. conducted a finite element analysis of the nail, which showed that the stability and stiffness of the implant bone decreased and the von Mises stress in the nail and bone increased with the decrease in the matching rate between the nail and the femoral bone marrow cavity[ 21 ]. A biomechanical study of 70 composite femur models by Durusoy et al. revealed that large-diameter intramedullary nail increases diaphyseal adherence to reduce the movement of the intramedullary nail in the femoral medullary cavity and decrease the risk of varus collapse and cutting rate of the screw, consequently[ 22 ]. Previous works demonstrated the higher matching degree of the nail might offer more satisfactory biomechanical properties for the nail-bone system. Whether a nail–bone system can meet the need for fracture healing depends on a variety of factors, not merely biomechanics[ 23 ]. More clinical analyses are needed to define the effect of the nail–canal gap on fracture healing. Subsequent clinical studies assessed the reoperation rate of proximal femoral intramedullary nails with diameters of 10 and > 10 mm in the treatment of intertrochanteric fractures and found no significant difference between the two groups ( P > 0.05)[ 15 ]; however, this study did not take into account the effect of individual differences in femoral marrow cavity. The matching degree of the nail depends on the difference or ratio of the diameter of the femoral marrow cavity and that of the intramedullary nail. We should not ignore the diameter of the femoral cavity by focusing only on the diameter of the intramedullary nail. In our study, the numbers of reoperation cases were as follows: 11 cases (13.7%) in high-matching group (gap ≤ 2 mm); 12 cases (13.8%) in middle-matching group (2 < gap < 4 mm); and 4 cases (11.1%) in low-matching group (gap ≥ 4 mm). No significant difference in reoperation rate was found among the three groups (P = 0.925, Table 2 ). Logistic regression showed no significant association was noted between matching degree of intramedullary nail and reoperation rate. (Table 3 ). The choice of intramedullary nail size remains controversial, which is often associated with complications resulting from the mismatch between the intramedullary nail and the femur, such as anterior cortical penetration and secondary fractures[ 15 , 24 ]. Chang et al. found that impingement of the anterior femoral cortex occurred in 34.8% of the cases in a study involving 158 patients with intertrochanteric fractures treated with proximal femoral anti-rotatory intramedullary nail (PFNA)[ 25 ]. Although nailing with small- and large-diameter intramedullary nails had similar rates of fracture healing and secondary fracture[ 15 ], small-diameter intramedullary nails tended to be used to decrease the incidence of anterior cortical impingement[ 24 , 26 ]; one scholar indicated that large-diameter nails would not bring more benefits to patients. Large-diameter nails relatively narrow the nail–canal gap, and the nail tip is more likely to ‘hit’ the anterior femoral cortex and lead to perforated fractures[ 24 ]. It was reported other factors might lead to secondary fracture of the femur[ 27 – 29 ]. Secondary fractures are more likely to occur in patients with long nails[ 27 ]. The nail will be deformed when the long nail does not match the femoral marrow cavity because of differences in the radius of curvature, and deformation resistance will make the nail tip ‘hit’ the anterior femoral cortex, resulting in perforated fractures[ 28 ]. For commercially available short nails, Ruecker et al. found that the bone cortex can be damaged by repeated drilling for distal locking or increased local stress, because the head of the distal locking bolt is too close to the lateral cortex, which may cause secondary femoral shaft fracture[ 29 ]. In our study, postoperative secondary femoral shaft fractures related to internal fixation were not observed, and the matching degree between proximal femoral intramedullary nail and femoral medullary cavity did not seem to be an important factor for reoperation, which supported that small-diameter nails could be used in lieu of large-diameter nails to reduce related complications. In our research, the cutting of the screw was the most common failure pattern of internal fixation, with a total of 11 cases, all of which were accompanied by varying degrees of coxa varus. Differing from the report of Zhang et al., the most common failure mode was cutting-out of screw instead of cutting[ 11 ]. Cutting-out occurred in only two cases, because most patients were required to avoid weight bearing or removing the lag screw when cutting combined with coax varus was observed during the follow-up period. At a tip-apex distance of greater than 25 mm, screws placed in the unduly anterior or upper position and coxa varus were potential risk factors for the cutting of the screw[ 30 ]. Fracture reduction quality is one of the most important predictors to consider when preventing a second operation, because cortical buttress improves cortical resistance to collapse. Poor reduction, especially with head-neck fragment varus, increases the risk of cortical collapse[ 11 ]. Pressure is chiefly transmitted through internal fixation, which increases the risk of cutting bone with a helical blade[ 31 ]. These statements explain why the most common cause of reoperation in our paper was coxa varus combined with cutting (11 cases). According to the experience of Baumgaertner et al[ 16 ], 103 cases (50.7%) were good, 67 cases (33.0%) were acceptable and 33 cases (16.3%) were poor in the reduction quality assessment. Logistic regression analysis (Table 3 ) showed that no strong dependency existed among explanatory variables, except for that between reduction quality and AO classification (6.798e-13). This finding demonstrated that unstable fracture patterns tended to lead to poor reduction quality. Unstable AO classification with poor reduction quality was the only significant variable where their 95% confidence interval does not include 1. Therefore, an association exists between unstable AO classification with poor reduction quality and reoperation ( p = 0.002). There were 20 cases (9.85%) of OTA/AO 31A3 fractures, as follows: “Good” reduction grade in 0 case (0%); “Acceptable” in 7 cases (35%); and “Poor” in 13 cases (65%). The reduction quality of OTA/AO 31A3 fractures tended to be identified as “poor.” Six cases (30%) of OTA/AO 31A3 fractures required second surgery, and this reoperation rate was higher than in other studies[ 15 ]. OTA/AO 31A3 fractures lead to a high rate of internal fixation failure due to difficulty in reduction. Baumgaertner and Solberg et al. reported that poor reduction quality resulted in a 3-fold higher rate of internal fixation failure for posterior intertrochanteric fractures[ 32 ]. Hao et al. also demonstrated that poor reduction quality and defects in the posterior medial cortex are factors of internal fixation failure for posterior intertrochanteric fractures[ 33 ]. The effect of nail length on reoperation rate was analyzed. In our study, nails with lengths of 170, 200 and 240 mm were used. Logistic regression analysis showed that the length of nail was not significantly associated with reoperation (P > 0.05, Table 3 ), which was in accordance with findings of previous studies[ 34 , 35 ]. The choice of the nail length was controversial. Although there were no significant differences in stability and failure of internal fixation between long and short nails reported in the current literature, patients on whom long nails were used experienced longer operation time and lost more blood[ 34 ]. Matching the long nail with femur was difficult due to the difference of the radius of curvature, thereby leading to a “hit” on the anterior femoral cortex and postoperative anterior knee pain, and surgeons prefer to use short nails[ 27 ]. Conclusions In summary, our studies found that the matching degree between proximal femoral intramedullary nail and femoral medullary cavity did not seem to be an important factor for reoperation, which offered more options of intramedullary nail size intraoperatively, reduced implants stock from inventory and costs to the healthcare systems and allowed orthopedic surgeons to used small-diameter nails in lieu of large-diameter ones for decreasing complications resulting from the mismatch between nail and bone. Some deficiencies exist in this study. Firstly, the patients were operated on by different surgeons, leading to varying degrees of impact on fracture reduction quality, operative incision size, operative time and intraoperative posture. This affected postoperative results, especially the reoperation rate. Secondly, patients' postoperative rehabilitation plans varied. Different rehabilitation plans may affect the postoperative results. In addition, the diameter of femoral marrow cavity was not uniform, thereby the diameter was measured at the level where the medullary cavity is most fully filled with distal nail considering the feasibility of the study. Declarations Author contributions All authors contribute to the study and approved the final manuscript. The manuscript and data collection were completed by Fei Wang, and research design and calibration of the manuscript were performed by Jian Shang. Ji-Long Zou conducted statistical analysis. Compliance with ethical standards The study did not receive any external funding. Declaration of Competing Interest : none References Hu SJ, Chang SM, Ma Z, et al. PFNA-II protrusion over the greater trochanter in the Asian population used in proximal femoral fractures. Indian J Orthop. 2016;50(6):641–646. Adeyemi A, Delhougne G. Incidence and Economic Burden of Intertrochanteric Fracture: A Medicare Claims Database Analysis. JB JS Open Access. 2019;4(1):e0045. 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Cite Share Download PDF Status: Published Journal Publication published 29 Dec, 2022 Read the published version in Journal of Orthopaedic Surgery and Research → Version 1 posted Editorial decision: Major revision 07 Dec, 2022 Reviews received at journal 23 Nov, 2022 Reviewers agreed at journal 03 Nov, 2022 Reviewers agreed at journal 03 Aug, 2022 Reviewers invited by journal 03 Aug, 2022 Editor assigned by journal 03 Aug, 2022 Submission checks completed at journal 02 Aug, 2022 First submitted to journal 31 Jul, 2022 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. 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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-1914789","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":125845017,"identity":"5137c7cd-d7d1-4b8c-8eb3-b0c35d1bd8d3","order_by":0,"name":"Fei Wang","email":"","orcid":"","institution":"The First Affiliated Hospital of Harbin Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Fei","middleName":"","lastName":"Wang","suffix":""},{"id":125845020,"identity":"285cc371-1fd5-4099-9f74-d8bdf1641a2c","order_by":1,"name":"Ji-Long Zou","email":"","orcid":"","institution":"The First Affiliated Hospital of Harbin Medical University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ji-Long","middleName":"","lastName":"Zou","suffix":""},{"id":125845021,"identity":"e0eac3a1-772b-4647-98b4-56f5b95787d6","order_by":2,"name":"Jian Shang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAwUlEQVRIiWNgGAWjYBAC+RkMCQc+GNjIMTATq8XgBkPiwRkFacYkaJFgYD7M8eFQYgPRDjOQbnhwmMHgQPr8dt6DHxhqbKIJapGfcyDhcIHBndwNh/mSJRiOpeUStu5GQsLhGQbPcjcw8xhIMDYcJlILj8HhdPlmHuMfJGlJYDjMY0acLQZALQdnGKQZbgBqsUggxi/yM3KSP3z4YyMv33/G+MaHGhsiHMbAk4BgJ+BShArYDxCnbhSMglEwCkYuAAADVUVd70SUPwAAAABJRU5ErkJggg==","orcid":"","institution":"Shenzhen University General Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Jian","middleName":"","lastName":"Shang","suffix":""}],"badges":[],"createdAt":"2022-07-31 15:14:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1914789/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1914789/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13018-022-03476-9","type":"published","date":"2022-12-29T18:07:29+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":24797562,"identity":"e665748d-7343-411c-8cd2-e8538b751bd5","added_by":"auto","created_at":"2022-08-04 17:42:37","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":727147,"visible":true,"origin":"","legend":"\u003cp\u003ePatient screening flow chart\u003c/p\u003e","description":"","filename":"Figure.1.png","url":"https://assets-eu.researchsquare.com/files/rs-1914789/v1/7a02a0e91920f426d4083fcb.png"},{"id":24797567,"identity":"7b9437de-3e21-4dd2-b215-610919f845af","added_by":"auto","created_at":"2022-08-04 17:42:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":8378446,"visible":true,"origin":"","legend":"\u003cp\u003e(a) AP radiograph. (b) Lateral radiograph. The diameter of femoral medullary cavity was measured at the layer where the medullary cavity was most fully filled with the distal nail.\u003c/p\u003e","description":"","filename":"Figure.2.png","url":"https://assets-eu.researchsquare.com/files/rs-1914789/v1/31b1a21cf5ccc0daf377bebc.png"},{"id":44715074,"identity":"8f323b90-d641-48f1-9471-67ee9792ae22","added_by":"auto","created_at":"2023-10-16 18:12:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1178727,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1914789/v1/26099619-cb63-4c4a-b2ca-798463266536.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Does matching degree matter for proximal femoral intramedullary nail on reoperation rate in intertrochanteric fractures?","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIntertrochanteric fracture occurs in elderly commonly, and most patients lose part of the hip function, which brings great burden to their families and constitutes a large part of the healthcare burden[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Intramedullary nailing has become a common treatment for intertrochanteric fracture. It is applied to various types of fracture with a good biomechanical performance. Intramedullary nailing allows patients to walk immediately after surgery[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. But implant failures are often reported. Previous studies have reported the failure patterns of internal fixation, including coxa varus, screw cutting, screw backing-out, prosthesis peripheral fracture and non-union[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Some studies forecasted the risk factors of implant failures, such as the tip-apex distance, lag screw placement, fracture pattern, reduction grade and osteoporosis[\u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. However, few studies were related to the effect of the matching degree between proximal femoral intramedullary nail and femoral medullary cavity on reoperation rate. The current study focuses on this effect to serve as a guide for choosing the size of nail intraoperatively.\u003c/p\u003e"},{"header":"Patients And Methods","content":" \u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003cp\u003e After obtaining the approval of the Ethics Committee of the First Affiliated Hospital of Harbin Medical University, a retrospective cohort study was conducted on patients with intertrochanteric fracture who were treated with proximal femoral anti-rotatory intramedullary nail (PFNA) between January 2016 and April 2021. Inclusion criteria included patients who were older than 60 years old and followed up for at least 24 weeks. Exclusion criteria included patients who had tumour-induced fracture, had serious medical disease and had to undergo long-term bed rest, had postoperative cognitive impairment and were unable to provide complete radiological image. The primary observational index was whether the reoperation was needed, and secondary observational indexes included operative time, length of hospital stay. Patient characteristics were recorded, as follows: age, sex, follow-up time, fracture pattern, reduction grade and length of intramedullary nail. The causes of reoperation were recorded, including coxa varus, screw cutting (extrusion with no cranial perforation), screw cutting-out (a cranial perforation), screw backing-out, prosthesis peripheral fracture, non-union and complications associated with internal fixation.\u003c/p\u003e \u003cp\u003eFractures were classified according to OTA/AO classification[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. OTA/AO 31A1 fractures were defined as stable fractures, and 31A2 and 31A3 fractures were defined as unstable fractures[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. According to the experience of Baumgaertner et al, the standard reduction was defined as follows. 1. The distance of the fracture fragment was ༜4 mm on standard anteroposterior and lateral radiographs. 2. The neck-shaft angle on AP view was normal or slightly valved (130\u0026deg;\u0026ndash;150\u0026deg;), and the angulation of fracture fragment was ༜20 \u0026deg; on Lat view. If both criteria were met, then the reduction quality was classified as good. If one criterion was met, then the reduction quality was classified as acceptable. If neither criteria was met, then it was classified as poor[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. There were three types of intramedullary nail lengths used, namely, 170, 200 and 240 mm. Only one distal static locking bolt was secured to the intramedullary nail due to the habit of the surgeon.\u003c/p\u003e \u003cp\u003eTo evaluate whether patients have achieved bone union, three criteria must be met, as follows: 1. at least three cortices showing continuous callus formation on standard anteroposterior and lateral radiographs; 2. absence of obvious pain on palpation and percussion at original fracture site; and 3. ability to walk without auxiliary devices[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The length and diameter of the intramedullary nail can be obtained from the surgical record. Considering that the diameter of femoral medullary cavity was not uniform, the diameter was measured at the level where the medullary cavity is most fully filled with distal nail by ImedPacs software system (Dong Hua Software Company, China) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The gap between the intramedullary nail and the femoral medullary cavity was equal to the difference in diameter between the two, and all patients were divided into three groups according to the gap: high-matching group: gap\u0026thinsp;\u0026le;\u0026thinsp;2 mm; middle-matching group: 2\u0026thinsp;\u0026lt;\u0026thinsp;gap\u0026thinsp;\u0026lt;\u0026thinsp;4 mm; and low-matching group: gap\u0026thinsp;\u0026ge;\u0026thinsp;4 mm. The grouping method was based on the experience of Richard et al[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] and the actual situation of this cohort study.\u003c/p\u003e \u003cp\u003eStatistical analysis: The statistical analysis was performed using R version 4.0.3. A Chi-Square Test was used to compare homogeneous distribution among categorical variables by evaluating frequencies within the groups. A one-way analysis of variance (ANOVA) test was used for comparing homogeneous distribution among numerical variables. Logistic regression was performed to analyze the relationships of reoperation with age, sex, fracture pattern and reduction quality, nail length and matching degree.\u003c/p\u003e \u003c/div\u003e "},{"header":"Result","content":" \u003cdiv id=\"Sec3\" type=\"Results\" class=\"Section2\"\u003e \u003cp\u003eA total of 203 patients were finally enrolled (Table\u0026nbsp;1). Eighty patients were in high-matching group (gap\u0026thinsp;\u0026le;\u0026thinsp;2 mm), 87 cases were in middle-matching group ( 2 mm\u0026thinsp;\u0026lt;\u0026thinsp;gap ༜ 4 mm) and 36 patients were in low-matching group (gap\u0026thinsp;\u0026ge;\u0026thinsp;4 mm). There were 78 males (38.4%) and 125 females (61.6%). The mean age of the patients was 77.8\u0026thinsp;\u0026plusmn;\u0026thinsp;9.9 years old, and the mean follow-up time was 58.1\u0026thinsp;\u0026plusmn;\u0026thinsp;24.0 weeks. Forty-eight cases were considered as stable fracture (23.6%), and 155 cases were considered as unstable fracture (76.4%). The cases with good, acceptable and poor fracture reduction grades were 103 (50.7%), 67 (33.0%) and 33 (16.3%), respectively.\u003c/p\u003e \u003cp\u003eTwenty-seven patients (13.3%) required additional surgery. The most common cause of reoperation is coxa varus combined with cutting of screw (11 cases). Other causes of reoperation include coxa varus combined with cutting-out of screw (two cases), coxa varus combined with back nail (three cases), simple coxa varus (two cases); non-union (four cases), pain associated with intramedullary nail stimulation (five cases). The three groups had 11 cases (13.7%), 12 cases (13.8%) and 4 cases (11.1%) of reoperation respectively, and no statistically significant difference was found among the groups (P\u0026thinsp;=\u0026thinsp;0.925).\u003c/p\u003e \u003cp\u003eStatistically significant differences were not observed among the three groups in age, gender, follow-up time, length of hospital stay, fracture patterns and reduction quality, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e2\u003c/span\u003e. However, a significant difference was found in the length of intramedullary nail (P\u0026thinsp;=\u0026thinsp;0.049). The differences of operative time among the three groups were also analyzed, and significant differences were not observed (P\u0026thinsp;=\u0026thinsp;0.071, 0.681, 0.767).\u003c/p\u003e \u003cp\u003eLogistic regression analysis was conducted (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Age, sex, nail length and gap size were not significant. Therefore, no significant association were found among them and reoperation. No strong dependency was observed among explanatory variables, except between reduction quality and fracture pattern (6.798e-13). Therefore, these two variables were combined together to one categorical variable with five levels (Stable, good; Stable, acceptable; Unstable, good; Unstable, acceptable and Unstable, poor). Unstable fracture pattern with poor reduction grade tended to contribute to reoperation, whose odds ratio (OR) was 6.61 (95% confidence interval [CI], 1.98\u0026ndash;22.09; p\u0026thinsp;=\u0026thinsp;0.002). Result showed matching degree was not a important factor of reoperation.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCharacteristics of intertrochanteric fractures in three groups.\u003c/p\u003e\n\u003ctable width=\"0\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"5\" width=\"588\"\u003e\n\u003cp\u003eCharacteristic\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; High matching group\u0026nbsp;\u0026nbsp; Middle matching group \u0026nbsp;\u0026nbsp;Low matching group\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; Combination\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003ePatient, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e80 (39.4%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e87 (42.9%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e36 (17.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e203 (100%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eAge, mean\u0026plusmn; SD (Year)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e76.6\u0026plusmn;10.7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e78.8\u0026plusmn;9.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e78.1\u0026plusmn;9.8\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e77.8\u0026plusmn;9.9\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eGender, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e37 (46.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e32 (36.8%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e9 (25.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e78 (38.4%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e43 (53.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e55 (63.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e27 (75.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e125 (61.6%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eFollow-up Time, mean\u0026plusmn; SD (Week)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e58.8\u0026plusmn;23.9\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e58.9\u0026plusmn;24.1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e54.7\u0026plusmn;24.7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e58.1\u0026plusmn;24.0\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eLength of Stay, mean\u0026plusmn; SD (Day)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e9.8\u0026plusmn;4.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e9.3\u0026plusmn;4.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e8.6\u0026plusmn;3.6\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e9.4\u0026plusmn;4.1\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eOperating Time, mean\u0026plusmn; SD (Minute)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e120.7\u0026plusmn;43.2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e107.7\u0026plusmn;35.2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e121.2\u0026plusmn;43.4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e115.2\u0026plusmn;40.3\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eFracture, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eStable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e21 (26.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e19 (21.8%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e8 (22.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e48 (23.6%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eUnstable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e59 (73.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e68 (78.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e28 (77.8%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e155 (76.4%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eQuality of Reduction, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eGood\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e41 (51.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e43 (49.4%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e19 (52.8%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e103 (50.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eAcceptable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e26 (32.5%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e33 (37.9%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e8 (22.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e67 (33.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003ePoor\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e13 (16.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e11 (12.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e9 (25.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e33 (16.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eNail Type, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003e170mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e27 (33.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e20 (23.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e9 (25.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e56 (27.6%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003e200mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e45 (56.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e64 (73.6%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e27 (75.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e136 (67.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003e240mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e8 (10.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e3 (3.4%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e0 (0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e11 (5.4%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003ePostoperative outcome, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eNon-reoperation\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e69 (86.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e75 (86.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e32 (88.9%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e176 (86.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"183\"\u003e\n\u003cp\u003eReoperation\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"101\"\u003e\n\u003cp\u003e11 (13.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"113\"\u003e\n\u003cp\u003e12 (13.8%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"102\"\u003e\n\u003cp\u003e4 (11.1%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"90\"\u003e\n\u003cp\u003e27 (13.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStatistically correlated results of three groups\u003c/p\u003e\n\u003ctable width=\"0\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"5\" width=\"588\"\u003e\n\u003cp\u003eCharacteristic\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;High matching group\u0026nbsp;\u0026nbsp; \u0026nbsp;Middle matching group \u0026nbsp;\u0026nbsp;Low matching group\u0026nbsp;\u0026nbsp; \u0026nbsp;\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eAge, mean\u0026plusmn; SD (Year)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e76.6\u0026plusmn;10.7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e78.8\u0026plusmn;9.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e78.1\u0026plusmn;9.8\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.352\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eFemale Gender, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e43 (53.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e55 (63.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e27 (75.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.086\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eFollow-up Time, mean\u0026plusmn; SD (Week)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e58.8\u0026plusmn;23.9\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e58.9\u0026plusmn;24.1\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e54.7\u0026plusmn;24.7\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e\u0026nbsp; 0.642\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eLength of Stay, mean\u0026plusmn; SD (Day)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e9.8\u0026plusmn;4.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e9.3\u0026plusmn;4.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e8.6\u0026plusmn;3.6\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.342\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eOperating Time, mean\u0026plusmn; SD (Minute)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e120.7\u0026plusmn;43.2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e107.7\u0026plusmn;35.2\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e121.2\u0026plusmn;43.4\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.071\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eUnstable Fracture pattern, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e59 (73.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e68 (78.2%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e28 (77.8%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.779\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003ePoor reduction grade, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e13 (16.3%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e11 (12.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e9 (25.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.358\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003e240mm Nail, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e8 (10.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e3 (3.4%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e0 (0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.049\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eReoperation, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"114\"\u003e\n\u003cp\u003e11 (13.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"109\"\u003e\n\u003cp\u003e12 (13.8%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"89\"\u003e\n\u003cp\u003e4 (11.1%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"78\"\u003e\n\u003cp\u003e0.925\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e. Logistic Regression Analysis\u003c/p\u003e\n\u003ctable width=\"0\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eRegression\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003eOdds Ratio\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e95% Confidence\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003eP-\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eModel\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003eRatio\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003eInterval\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003evalue\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eAge\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e1.01\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.96-1.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.811\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eGender\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eMale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e0.42\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.15-1.20\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.106\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eFemale\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eFracture pattern and\u003c/p\u003e\n\u003cp\u003ereduction grade\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eStable, good\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e0.19\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.02-1.62\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.129\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eStable, acceptable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e1.14\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.12-11.19\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.909\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eUnstable, good\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e0.77\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.22-2.67\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.683\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eUnstable, acceptable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eUnstable, poor\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e6.61\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e1.98-22.09\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.002\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eNail Length\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003e170mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003e200mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e1.21\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.39-3.77\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.739\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003e240mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e2.63\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.45-15.41\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.284\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eMatching degree\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eHigh matching degree\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003eRef\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eMiddle matching degree\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e2.43\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.58-10.23\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.225\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd width=\"198\"\u003e\n\u003cp\u003eLow matching degree\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"128\"\u003e\n\u003cp\u003e2.22\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"133\"\u003e\n\u003cp\u003e0.50-9.94\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd width=\"87\"\u003e\n\u003cp\u003e0.295\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe matching degree between the nail and femoral medullary cavity might affect fracture healing[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Millar et al.\u0026rsquo;s study of femoral shaft fractures asserted that a satisfactory nail fit allows smaller interfragmentary movement, which results in a more satisfactory outcome; they recommended an ideal nail fit of 90% at the isthmus to avoid surgical re-intervention[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, the biomechanics of intertrochanteric fractures are different from those of femoral shaft fractures. Studies describing matching rate as an indicator of fracture healing and stability for intertrochanteric fractures are few. Some scholars have compared the effect of the matching degree of intramedullary nail on stability from the perspective of biomechanics. Simpson et al. conducted a finite element analysis of the nail, which showed that the stability and stiffness of the implant bone decreased and the von Mises stress in the nail and bone increased with the decrease in the matching rate between the nail and the femoral bone marrow cavity[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. A biomechanical study of 70 composite femur models by Durusoy et al. revealed that large-diameter intramedullary nail increases diaphyseal adherence to reduce the movement of the intramedullary nail in the femoral medullary cavity and decrease the risk of varus collapse and cutting rate of the screw, consequently[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Previous works demonstrated the higher matching degree of the nail might offer more satisfactory biomechanical properties for the nail-bone system.\u003c/p\u003e \u003cp\u003eWhether a nail\u0026ndash;bone system can meet the need for fracture healing depends on a variety of factors, not merely biomechanics[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. More clinical analyses are needed to define the effect of the nail\u0026ndash;canal gap on fracture healing. Subsequent clinical studies assessed the reoperation rate of proximal femoral intramedullary nails with diameters of 10 and \u0026gt;\u0026thinsp;10 mm in the treatment of intertrochanteric fractures and found no significant difference between the two groups (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05)[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]; however, this study did not take into account the effect of individual differences in femoral marrow cavity. The matching degree of the nail depends on the difference or ratio of the diameter of the femoral marrow cavity and that of the intramedullary nail. We should not ignore the diameter of the femoral cavity by focusing only on the diameter of the intramedullary nail. In our study, the numbers of reoperation cases were as follows: 11 cases (13.7%) in high-matching group (gap\u0026thinsp;\u0026le;\u0026thinsp;2 mm); 12 cases (13.8%) in middle-matching group (2\u0026thinsp;\u0026lt;\u0026thinsp;gap\u0026thinsp;\u0026lt;\u0026thinsp;4 mm); and 4 cases (11.1%) in low-matching group (gap\u0026thinsp;\u0026ge;\u0026thinsp;4 mm). No significant difference in reoperation rate was found among the three groups (P\u0026thinsp;=\u0026thinsp;0.925, Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Logistic regression showed no significant association was noted between matching degree of intramedullary nail and reoperation rate. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe choice of intramedullary nail size remains controversial, which is often associated with complications resulting from the mismatch between the intramedullary nail and the femur, such as anterior cortical penetration and secondary fractures[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Chang et al. found that impingement of the anterior femoral cortex occurred in 34.8% of the cases in a study involving 158 patients with intertrochanteric fractures treated with proximal femoral anti-rotatory intramedullary nail (PFNA)[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Although nailing with small- and large-diameter intramedullary nails had similar rates of fracture healing and secondary fracture[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e], small-diameter intramedullary nails tended to be used to decrease the incidence of anterior cortical impingement[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]; one scholar indicated that large-diameter nails would not bring more benefits to patients. Large-diameter nails relatively narrow the nail\u0026ndash;canal gap, and the nail tip is more likely to \u0026lsquo;hit\u0026rsquo; the anterior femoral cortex and lead to perforated fractures[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. It was reported other factors might lead to secondary fracture of the femur[\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Secondary fractures are more likely to occur in patients with long nails[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The nail will be deformed when the long nail does not match the femoral marrow cavity because of differences in the radius of curvature, and deformation resistance will make the nail tip \u0026lsquo;hit\u0026rsquo; the anterior femoral cortex, resulting in perforated fractures[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. For commercially available short nails, Ruecker et al. found that the bone cortex can be damaged by repeated drilling for distal locking or increased local stress, because the head of the distal locking bolt is too close to the lateral cortex, which may cause secondary femoral shaft fracture[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. In our study, postoperative secondary femoral shaft fractures related to internal fixation were not observed, and the matching degree between proximal femoral intramedullary nail and femoral medullary cavity did not seem to be an important factor for reoperation, which supported that small-diameter nails could be used in lieu of large-diameter nails to reduce related complications.\u003c/p\u003e \u003cp\u003eIn our research, the cutting of the screw was the most common failure pattern of internal fixation, with a total of 11 cases, all of which were accompanied by varying degrees of coxa varus. Differing from the report of Zhang et al., the most common failure mode was cutting-out of screw instead of cutting[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Cutting-out occurred in only two cases, because most patients were required to avoid weight bearing or removing the lag screw when cutting combined with coax varus was observed during the follow-up period. At a tip-apex distance of greater than 25 mm, screws placed in the unduly anterior or upper position and coxa varus were potential risk factors for the cutting of the screw[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFracture reduction quality is one of the most important predictors to consider when preventing a second operation, because cortical buttress improves cortical resistance to collapse. Poor reduction, especially with head-neck fragment varus, increases the risk of cortical collapse[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Pressure is chiefly transmitted through internal fixation, which increases the risk of cutting bone with a helical blade[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. These statements explain why the most common cause of reoperation in our paper was coxa varus combined with cutting (11 cases). According to the experience of Baumgaertner et al[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], 103 cases (50.7%) were good, 67 cases (33.0%) were acceptable and 33 cases (16.3%) were poor in the reduction quality assessment. Logistic regression analysis (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e) showed that no strong dependency existed among explanatory variables, except for that between reduction quality and AO classification (6.798e-13). This finding demonstrated that unstable fracture patterns tended to lead to poor reduction quality. Unstable AO classification with poor reduction quality was the only significant variable where their 95% confidence interval does not include 1. Therefore, an association exists between unstable AO classification with poor reduction quality and reoperation (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.002). There were 20 cases (9.85%) of OTA/AO 31A3 fractures, as follows: \u0026ldquo;Good\u0026rdquo; reduction grade in 0 case (0%); \u0026ldquo;Acceptable\u0026rdquo; in 7 cases (35%); and \u0026ldquo;Poor\u0026rdquo; in 13 cases (65%). The reduction quality of OTA/AO 31A3 fractures tended to be identified as \u0026ldquo;poor.\u0026rdquo; Six cases (30%) of OTA/AO 31A3 fractures required second surgery, and this reoperation rate was higher than in other studies[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. OTA/AO 31A3 fractures lead to a high rate of internal fixation failure due to difficulty in reduction. Baumgaertner and Solberg et al. reported that poor reduction quality resulted in a 3-fold higher rate of internal fixation failure for posterior intertrochanteric fractures[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Hao et al. also demonstrated that poor reduction quality and defects in the posterior medial cortex are factors of internal fixation failure for posterior intertrochanteric fractures[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe effect of nail length on reoperation rate was analyzed. In our study, nails with lengths of 170, 200 and 240 mm were used. Logistic regression analysis showed that the length of nail was not significantly associated with reoperation (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05, Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e3\u003c/span\u003e), which was in accordance with findings of previous studies[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. The choice of the nail length was controversial. Although there were no significant differences in stability and failure of internal fixation between long and short nails reported in the current literature, patients on whom long nails were used experienced longer operation time and lost more blood[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Matching the long nail with femur was difficult due to the difference of the radius of curvature, thereby leading to a \u0026ldquo;hit\u0026rdquo; on the anterior femoral cortex and postoperative anterior knee pain, and surgeons prefer to use short nails[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn summary, our studies found that the matching degree between proximal femoral intramedullary nail and femoral medullary cavity did not seem to be an important factor for reoperation, which offered more options of intramedullary nail size intraoperatively, reduced implants stock from inventory and costs to the healthcare systems and allowed orthopedic surgeons to used small-diameter nails in lieu of large-diameter ones for decreasing complications resulting from the mismatch between nail and bone.\u003c/p\u003e \u003cp\u003eSome deficiencies exist in this study. Firstly, the patients were operated on by different surgeons, leading to varying degrees of impact on fracture reduction quality, operative incision size, operative time and intraoperative posture. This affected postoperative results, especially the reoperation rate. Secondly, patients' postoperative rehabilitation plans varied. Different rehabilitation plans may affect the postoperative results. In addition, the diameter of femoral marrow cavity was not uniform, thereby the diameter was measured at the level where the medullary cavity is most fully filled with distal nail considering the feasibility of the study.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contribute to the study and approved the final manuscript. The manuscript and data collection were completed by Fei Wang, and research design and calibration of the manuscript were performed by Jian Shang. Ji-Long Zou conducted statistical analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompliance with ethical standards\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study did not receive any external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of Competing Interest\u003c/strong\u003e: none\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHu SJ, Chang SM, Ma Z, et al. PFNA-II protrusion over the greater trochanter in the Asian population used in proximal femoral fractures. Indian J Orthop. 2016;50(6):641\u0026ndash;646.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAdeyemi A, Delhougne G. Incidence and Economic Burden of Intertrochanteric Fracture: A Medicare Claims Database Analysis. JB JS Open Access. 2019;4(1):e0045.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu Y, Tao R, Liu F, et al. Mid-term outcomes after intramedullary fixation of peritrochanteric femoral fractures using the new proximal femoral nail antirotation (PFNA). Injury. 2010;41(8):810\u0026ndash;817.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSocci AR, Casemyr NE, Leslie MP, et al. Implant options for the treatment of intertrochanteric fractures of the hip: rationale, evidence, and recommendations. Bone Joint J. 2017;99-B(1):128\u0026ndash;133.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrunner A, Jockel JA, Babst R. The PFNA proximal femur nail in treatment of unstable proximal femur fractures\u0026ndash;3 cases of postoperative perforation of the helical blade into the hip joint. J Orthop Trauma. 2008;22(10):731\u0026ndash;736.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGoodnough LH, Salazar BP, Furness J, et al. How are peri-implant fractures below short versus long cephalomedullary nails different? Eur J Orthop Surg Traumatol. 2021;31(3):421\u0026ndash;427.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang H, Zeng X, Zhang N, et al. INTERTAN nail versus proximal femoral nail antirotation-Asia for intertrochanteric femur fractures in elderly patients with primary osteoporosis. J Int Med Res. 2017;45(4):1297\u0026ndash;1309.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCaruso G, Bonomo M, Valpiani G, et al. A six-year retrospective analysis of cut-out risk predictors in cephalomedullary nailing for pertrochanteric fractures: Can the tip-apex distance (TAD) still be considered the best parameter? Bone Joint Res. 2017;6(8):481\u0026ndash;488.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrei HC, Hotz T, Cadosch D, et al. Central head perforation, or \"cut through,\" caused by the helical blade of the proximal femoral nail antirotation. J Orthop Trauma. 2012;26(8):e102-107.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTurgut A, Kalenderer O, Karapinar L, et al. Which factor is most important for occurrence of cutout complications in patients treated with proximal femoral nail antirotation? Retrospective analysis of 298 patients. Arch Orthop Trauma Surg. 2016;136(5):623\u0026ndash;630.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang W, Antony Xavier RP, Decruz J, et al. Risk factors for mechanical failure of intertrochanteric fractures after fixation with proximal femoral nail antirotation (PFNA II): a study in a Southeast Asian population. Arch Orthop Trauma Surg. 2021;141(4):569\u0026ndash;575.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKonstantinidis L, Helwig P, Hirschmuller A, et al. When is the stability of a fracture fixation limited by osteoporotic bone? Injury. 2016;47 Suppl 2:S27-32.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarrios C, Brostrom LA, Stark A, et al. Healing complications after internal fixation of trochanteric hip fractures: the prognostic value of osteoporosis. J Orthop Trauma. 1993;7(5):438\u0026ndash;442.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMeinberg EG, Agel J, Roberts CS, et al. Fracture and Dislocation Classification Compendium-2018. J Orthop Trauma. 2018;32 Suppl 1:S1-S170.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRinehart DB, O'Neill DE, Liu JW, et al. Does Size Matter for Cephalomedullary Nails in Geriatric Intertrochanteric Fractures? J Orthop Trauma. 2021;35(6):329\u0026ndash;332.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaumgaertner MR, Curtin SL, Lindskog DM, et al. The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg Am. 1995;77(7):1058\u0026ndash;1064.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDijkman BG, Sprague S, Schemitsch EH, et al. When is a fracture healed? Radiographic and clinical criteria revisited. J Orthop Trauma. 2010;24 Suppl 1:S76-80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMorshed S. Current Options for Determining Fracture Union. Adv Med. 2014;2014:708574.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYoon RS, Adams DM, Seigerman DA, et al. Impact of Surrounding Canal Size on Time to Union After Intramedullary Nailing of Femur Fractures: Are 10-mm Nails All We Need? J Orthop Trauma. 2020;34(4):180\u0026ndash;185.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMillar MJ, Wilkinson A, Navarre P, et al. Nail Fit: Does Nail Diameter to Canal Ratio Predict the Need for Exchange Nailing in the Setting of Aseptic, Hypertrophic Femoral Nonunions? J Orthop Trauma. 2018;32(5):245\u0026ndash;250.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSimpson DJ, Brown CJ, Yettram AL, et al. Finite element analysis of intramedullary devices: the effect of the gap between the implant and the bone. Proc Inst Mech Eng H. 2008;222(3):333\u0026ndash;345.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDurusoy S, Paksoy AE, Korkmaz M, et al. The effect of medullary fill on varus collapse in AO 31A3 intertrochanteric (reverse obliquity) fracture treated with cephalomedullary nails. Orthop Traumatol Surg Res. 2021;107(3):102804.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRupp M, Biehl C, Budak M, et al. Diaphyseal long bone nonunions - types, aetiology, economics, and treatment recommendations. Int Orthop. 2018;42(2):247\u0026ndash;258.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrederick M. Azar JHB, S. Terry Canale,. CAMPBELLS OPERATIVE ORTHOPAEDICS. Vol\u0026nbsp;6. The United States2017.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChang SM, Song DL, Ma Z, et al. Mismatch of the short straight cephalomedullary nail (PFNA-II) with the anterior bow of the Femur in an Asian population. J Orthop Trauma. 2014;28(1):17\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark JH, Lee Y, Shon OJ, et al. Surgical tips of intramedullary nailing in severely bowed femurs in atypical femur fractures: Simulation with 3D printed model. Injury. 2016;47(6):1318\u0026ndash;1324.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuque Perez R, Checa Betegon P, Galan-Olleros M, et al. Nailing unstable pertrochanteric fractures: does size matters? Arch Orthop Trauma Surg. 2022;142(1):145\u0026ndash;155.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYuan H, Acklin Y, Varga P, et al. A cadaveric biomechanical study comparing the ease of femoral nail insertion: 1.0- vs 1.5-m bow designs. Arch Orthop Trauma Surg. 2017;137(5):663\u0026ndash;671.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRuecker AH, Rueger JM. Pertrochanteric fractures: tips and tricks in nail osteosynthesis. Eur J Trauma Emerg Surg. 2014;40(3):249\u0026ndash;264.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAndruszkow H, Frink M, Fromke C, et al. Tip apex distance, hip screw placement, and neck shaft angle as potential risk factors for cut-out failure of hip screws after surgical treatment of intertrochanteric fractures. Int Orthop. 2012;36(11):2347\u0026ndash;2354.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReindl R, Harvey EJ, Berry GK, et al. Intramedullary Versus Extramedullary Fixation for Unstable Intertrochanteric Fractures: A Prospective Randomized Controlled Trial. J Bone Joint Surg Am. 2015;97(23):1905\u0026ndash;1912.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaumgaertner MR, Solberg BD. Awareness of tip-apex distance reduces failure of fixation of trochanteric fractures of the hip. J Bone Joint Surg Br. 1997;79(6):969\u0026ndash;971.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHao Y, Zhang Z, Zhou F, et al. Risk factors for implant failure in reverse oblique and transverse intertrochanteric fractures treated with proximal femoral nail antirotation (PFNA). J Orthop Surg Res. 2019;14(1):350.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShannon SF, Yuan BJ, Cross WW, 3rd, et al. Short Versus Long Cephalomedullary Nails for Pertrochanteric Hip Fractures: A Randomized Prospective Study. J Orthop Trauma. 2019;33(10):480\u0026ndash;486.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHorwitz DS, Tawari A, Suk M. Nail Length in the Management of Intertrochanteric Fracture of the Femur. J Am Acad Orthop Surg. 2016;24(6):e50-58.\u003c/span\u003e\u003c/li\u003e\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":"Intertrochanteric fracture, Matching degree, Gap, Reoperation","lastPublishedDoi":"10.21203/rs.3.rs-1914789/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1914789/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIntroduction\u003c/p\u003e\u003cp\u003ePrevious articles reported on the tip-apex distance, lag screw placement, fracture pattern, reduction quality, osteoporosis and other factors associated with second surgery. The current study focused on investigating the association of the matching degree between proximal femoral intramedullary nail and femoral medullary cavity on reoperation rate.\u003c/p\u003e\u003cp\u003ePatients and methods\u003c/p\u003e\u003cp\u003eA retrospective cohort study was conducted. It included patients with intertrochanteric fracture who were treated with proximal femoral anti-rotatory intramedullary nail (PFNA) between January 2016 and April 2021. The gap between the intramedullary nail and the femoral medullary cavity was equal to the difference in diameter between the two. According to the gap size, all patients were divided into three groups, as follows: high-matching group: gap ≤ 2 mm; middle-matching group: 2 \u0026lt; gap \u0026lt; 4 mm; and low-matching group: gap ≥ 4 mm. The mean gap was measured through standard images. The primary observational index was whether the reoperation was needed, and secondary observational indexes included operative time, length of hospital stay. Patient characteristics were recorded, as follows: age, sex, follow-up time, fracture pattern, reduction grade and length of intramedullary nail.\u003c/p\u003e\u003cp\u003eResults\u003c/p\u003e\u003cp\u003eA total of 203 eligible patients were recorded, including 78 males (38.4%) and 125 females (61.6%). They had a mean age of 77.8 ± 9.9 years old and an average follow-up time of 58.1 ± 24.0 weeks. Twenty-seven patients (13.3%) needed a second operation. Coxa varus combined with screw cutting was the most common reason for reoperation (11 cases). Unstable fracture pattern with poor reduction grade tended to contribute to reoperation, whose odds ratio (OR) was 6.61 (95% confidence interval [CI], 1.98–22.09; p = 0.002). The three groups had 11 cases (13.7%), 12 cases (13.8%) and 4 cases (11.1%) of reoperation respectively and logistic regression showed no significant association was noted between matching degree of intramedullary nail and reoperation rate.\u003c/p\u003e\u003cp\u003eConclusions\u003c/p\u003e\u003cp\u003eThe matching degree between proximal femoral intramedullary nail and femoral medullary cavity did not seem to be an important factor for reoperation, which offered more options of intramedullary nail size intraoperatively and reduced implants stock from inventory.\u003c/p\u003e","manuscriptTitle":"Does matching degree matter for proximal femoral intramedullary nail on reoperation rate in intertrochanteric fractures?","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-08-04 17:42:35","doi":"10.21203/rs.3.rs-1914789/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-12-07T06:13:16+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-11-24T00:12:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"29c66c46-6c7c-475b-ab82-99c154d6eb8b","date":"2022-11-03T09:59:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"770a7e97-2a93-4c48-b5f5-cdb6da2222f9","date":"2022-08-03T07:01:27+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-08-03T06:59:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-08-03T06:56:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-08-02T12:24:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Orthopaedic Surgery and Research","date":"2022-07-31T15:00:08+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":"9a1cfb76-fa1e-405e-a8df-50ac1550c89b","owner":[],"postedDate":"August 4th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T18:09:33+00:00","versionOfRecord":{"articleIdentity":"rs-1914789","link":"https://doi.org/10.1186/s13018-022-03476-9","journal":{"identity":"journal-of-orthopaedic-surgery-and-research","isVorOnly":false,"title":"Journal of Orthopaedic Surgery and Research"},"publishedOn":"2022-12-29 18:07:29","publishedOnDateReadable":"December 29th, 2022"},"versionCreatedAt":"2022-08-04 17:42:35","video":"","vorDoi":"10.1186/s13018-022-03476-9","vorDoiUrl":"https://doi.org/10.1186/s13018-022-03476-9","workflowStages":[]},"version":"v1","identity":"rs-1914789","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1914789","identity":"rs-1914789","version":["v1"]},"buildId":"FbvkV6FR0MCFSLy54lSbu","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}