Biomechanical evaluation of a central collinear entry reconstruction nail for femoral neck fracture prophylaxis.

INTRODUCTION: Reconstruction nails are commonly used to treat proximal femur fractures, with cephalic screw placement for femoral neck "prophylaxis" becoming standard practice. These implants are traditionally introduced through piriformis fossa (PF) or greater trochanter (GT) entry portals. A third "central collinear" (CC) portal has been proposed that allows entry along the femoral anatomic axis and central placement of cephalic screws. The present study aimed to quantify and compare the CC portal femoral neck strength with the two traditional (PF and GT) entry portals. MATERIALS AND METHODS: Eighteen cadaveric femur specimens (nine matched pairs) were divided into three groups using a balanced incomplete block design to control for variations in age and sex: (1) GT, (2) CC, and (3) PF entry points. Specimens and implants were cut to a standard length and instrumented with straight or valgus bend nails of appropriate laterality and two cephalic screws. Specimens were mounted on a custom jig replicating load distribution along the mechanical axis. A 100 N compressive preload was applied to the femoral head, followed by loading to failure at a rate of 10 mm/s until fracture, indicated by 30 % drop in axial force. RESULTS: THE THREE ENTRY POINTS DID NOT DIFFER IN LOAD-TO-FAILURE: GT (6378.7 ± 1494.9 N), P (6912.4 ± 4924.1 N) and CC (7044.2 ± 2911.4 N) (P = 0.948) or maximum displacement, stiffness, and toughness. Most PF specimens failed at the basicervical neck, whereas most GT specimens failed at the subcapital neck; these differences were not significant. CC specimens failed evenly split between subcapital and basicervical. CONCLUSION: There were no significant difference in femoral neck load-to-failure after placement of a reconstruction nail through a CC entry portal when compared to both GT and PF entry. Clinically, this suggests the CC entry portal is a viable option when clinical considerations warrant its use.

Subchondral rafting wires reduce tibial plateau fracture subsidence.

PURPOSE: To determine if subchondral rafting wires retained as adjunctive tibial plateau fracture fixation affect postoperative articular subsidence. METHODS: A retrospective cohort study was conducted at one Level 1 trauma center and one academic university hospital. Consecutive adults with closed, displaced OTA/AO 41B/C tibial plateau fractures treated between 2018 and 2023 with open reduction internal fixation were included. Patients who were not ambulatory, with contralateral injuries limiting weight bearing, and without follow-up radiographs of the injured extremity were excluded. The intervention was retention of subchondral rafting wires as definitive fixation. The primary outcome was linear articular surface subsidence between postoperative and follow-up AP knee radiographs. Linear subsidence was compared between groups using Welch's two sample t test. Associations of linear subsidence with patient, injury, and treatment characteristics were assessed by multivariable linear regression. RESULTS: We identified 179 patients of a mean age of 44 ± 14 years, of whom 15 (8.4%) received subchondral rafting wires. Median follow-up was 121 days. No patients who received rafting wires as definitive implants experienced linear subsidence ≥ 2 mm, while 22 patients (13.4%) who did not receive rafting wires experienced linear subsidence ≥ 2 mm (p = 0.130). Subchondral rafting wires were associated with less linear subsidence (0.3 mm [95% confidence interval - 0.3-0.9 mm] vsersus 1.0 mm [- 0.9-2.9 mm], p < 0.001). The depth of linear subsidence was significantly associated on multivariable regression with male sex, depressed plateau area, active smoking, and retained rafting wires. CONCLUSION: Subchondral rafting wires were associated with a small reduction in articular subsidence after internal fixation of tibial plateau fractures. Routine rafting wires may be useful for patients and fractures at high risk of articular subsidence.

Current Management of Acute and Posttraumatic Critical Bone Defects.

SUMMARY: Limb reconstruction in patients with critical-sized bone defects remains a challenge due to the availability of various technically demanding treatment options and a lack of standardized decision algorithms. Although no consensus exists, it is apparent from the literature that the combination of patient, surgeon, and institutional collaborations is effective in providing the most efficient care pathway for these patients. Success relies on choosing a particular surgical approach that manages infection, soft tissue defects, stability, and alignment. Recent systematic reviews demonstrate high success rates with the following management options: Ilizarov bone transport, Masquelet (induced membrane) technique, cancellous bone grafting, and vascularized bone grafts.

Optimizing the Entry Point for Medullary Hip Screws.

INTRODUCTION: Medullary hip screws (MHSs) are the most common treatment of intertrochanteric hip fractures because they can be used for varied fracture patterns and resist shortening. Identifying the appropriate MHS entry point can be intellectually and technically challenging. We aimed to quantify the variability in the ideal entry point (IEP) for MHSs. METHODS: Standing alignment radiographs of 50 patients were evaluated using TraumaCad (Brainlab). The femoral neck shaft angle and the offset from the tip of the greater trochanter (GT) to the femur's longitudinal axis ('greater trochanter offset') were measured. Five MHS system templates were superimposed on the femur's longitudinal axis, and the distance from the GT tip to MHS's top center was measured. Five independent reviewers each templated 20 images such that all images were measured at least twice. A random sample of five images was selected for all five raters to measure and to calculate an intraclass coefficient Mean IEPs were compared with an independent sample Student t -test. RESULTS: The mean GT offset was 13.5 ± 5.6 mm (range 12.9 to 26.7 mm). The mean neck shaft angle was 129.5 ± 4.0 (range 120 to 139). The mean IEP for nail systems ranged from 5.7 to 7.1 mm medial to the GT tip; there was no notable difference in pairwise comparison of nail systems or in aggregate. Intraclass coefficient for all ratings, measurements, and nail types ranged from moderate to good. Both intra-rater and inter-rater reliability were excellent. DISCUSSION AND CONCLUSION: In a sample with broad variation in femoral anatomy, there is a specific, roughly 1.5 mm wide interval that is 6.4 mm medial to the GT tip that serves as the IEP for the most common MHS systems. No notable difference seems to exist in the IEP among these MHS systems.

Limb position affects intraoperative assessment of condylar width.

PURPOSE: We sought to define how changes in position and rotation of fluoroscopic imaging may affect the assessment of condylar widening intraoperatively. METHODS: Thirty-three patients with tibial plateau fractures were prospectively identified and included in this study. Fluoroscopic images of the uninjured tibial plateau were obtained in (1) full extension and (2) slight flexion on foam ramp. Beginning with a plateau view, additional views of the tibial plateau were then obtained by rotating the fluoroscope around the knee in 5 degree increments up to 15 degrees in both internal and external rotation. Measurements of distal femoral condylar width (DFW), distal femoral articular width (FAW), proximal tibial articular width (TAW) and lateral plateau width (LPW) were performed. RESULTS: LPW was decreased in flexion compared to extension at all degrees of rotation (p = 0.04-0.00001). There was a trend toward increasing LPW with increasing degrees of internal rotation which reached significance at 15˚ of internal rotation when the knee was flexed. On ANOVA, there was a significant difference of LPW with increasing degree of internal rotation when the knee was in flexion (p = 0.008), but not in extension. There were no differences in DFW, FAW, TAW and DFW/TAW at any point though LPW was decreased in flexion at all degrees of rotation. The FAW/TAW ratio was increased in flexion at all degrees of rotation. DISCUSSION: The knee in flexion will underestimate the measurement of condylar width compared to the knee in full extension, by ~ 2 mm. Rotation of the knee, in comparison, did not have a significant effect on condylar width assessment. LEVEL OF EVIDENCE: Diagnostic II.

Axial Plane Deformity: How to Avoid It and How to Correct It.

Malreductions in the axial plane (ie, length and rotation) are common when managing long bone fractures. Careful attention to detail during the initial treatment can prevent these malreductions. Various fluoroscopy-based techniques exist for the prevention of malrotation and limb-length discrepancy during surgery for fracture. If malreductions do occur, a systematic clinical and radiographic evaluation can provide the necessary information to correct rotational malreduction and limb-length discrepancy.

Does Fibular Displacement Predict Tibial Malrotation in Simulated Tibia-Fibula Fractures.

INTRODUCTION: Tibial malrotation can occur with medullary nailing of diaphyseal tibial fractures. Fibular alignment has been proposed as a surrogate for axial plane reduction intraoperatively. The purpose of this study was to determine whether fibular alignment is a reliable marker of accurate tibial rotation. METHODS: Deidentified CT scans of 50 patients with normal tibial anatomy were selected. Using ImageJ software, we simulated osteotomies at three sites (proximal third, mid-diaphysis, and distal third). We overlaid adjacent CT slices and rotated them around the central axis of the tibia in 5° increments of external rotation (ER) and internal rotation (IR). At each increment, measurements of fibular overlap (%) were obtained from anteroposterior (AP) and lateral views. To simulate fixation of the fibula, we repeated rotation around the axis of the fibula with and without a simulated medullary implant in the tibia. RESULTS: A total of 50 patients were included. The mean age was 62 years, average BMI was 25.8, and 28 of 50 patients (56%) were male. Earliest loss of fibular contact occurred at 24° ER and 22° IR at the proximal site. Contact was lost at 26° ER and 28° IR on the AP view and 42° ER and 29° IR on the lateral view. The mean fibular contact at each 5° increment was similar for ER and IR. Fibular contact was reduced to 50% at 10 to 15° of rotation in ER and IR at all sites. Tibial canal contact was lost at 24° in both ER and IR around the fibula. With a virtual medullary implant, the mean maximal rotation was 6°. DISCUSSION: Surgeons should be aware that 20° or more of malrotation is likely present when fibular contact is lost during medullary nailing of the tibia. Greater than 50% loss of contact should raise suspicion for malrotation. A fixed fibula and medullary tibial implant theoretically preclude significant tibial malrotation.

Orthopaedic Advances: Use of Three-Dimensional Metallic Implants for Reconstruction of Critical Bone Defects After Trauma.

Multiple successful strategies exist for the management of critical-sized bone defects. Depending on the location and etiology of an osseous defect, there are nuances that must be considered by the treating surgeon. The induced membrane technique and various modifications of the Ilizarov method (bone transport by distraction osteogenesis) have been the most common methods for biologic reconstruction. Despite the versatility and high union rates reported, they may not be practical for every patient. The rapid expansion of three-dimensional printing of medical devices has led to an increase in their use within orthopaedic surgery, specifically in the definitive treatment of critical bone defects. This article proposes indications and contraindications for implementation of this technology and reviews the available clinical evidence on the use of custom nonresorbable implants for the treatment of traumatic bone loss. Clinical cases are presented to illustrate the scenarios in which this approach is viable.

Standard versus low-dose computed tomography for assessment of acetabular fracture reduction using novel step and gap measurement technique.

PURPOSE: Quality of reduction is of paramount importance after acetabular fracture and is best assessed on computed tomography (CT). A recently proposed measurement technique for assessment of step and gap displacement is reproducible but has not been validated. The purpose of this study is to validate a well-established measurement technique against known displacements and to determine if it can be used with low dose CT. METHODS: Posterior wall acetabular fractures were created in 8 cadaveric hips and fixed at known step and gap displacements. CT was performed at multiple radiation doses for each hip. Four surgeons measured step and gap displacement for each hip at all doses, and the measurements were compared to known values. RESULTS: There were no significant differences in measurements across surgeons, and all measurements were found to have positive agreement. Measurement error < 1.5 mm was present in 58% of gap measurements and 46% of step measurements. Only for step measurements at a dose of 120 kVp did we observe a statistically significant measurement error. There was a significant difference in step measurements made by those with greater and those with fewer years in practice. CONCLUSION: Our study suggests this technique is valid and accurate across all doses. This is important as it may reduce the amount of radiation exposure for patients with acetabular fractures.

Optimizing the Entry Point for Reconstruction Nailing of the Femur.

INTRODUCTION: Varus after antegrade medullary nailing of the proximal femur is associated with worse outcomes. Anecdotally, a more medialized "trochiformis" entry is beneficial to avoid varus with valgus-bend (greater trochanteric entry) femoral nails. However, the optimal entry point remains unknown. The purpose of this study was to define the optimal entry point for reconstruction nailing. METHODS: Using standing alignment radiographs from 51 patients, we templated the ideal entry point for straight and valgus-bend nails from three major manufacturers using TraumaCad software. We measured the distance from the tip of the trochanter to the ideal entry site for each nail. We compared piriformis (PF) with trochanteric (GT) entry for each company and across manufacturers. RESULTS: The mean greater trochanter offset from the femoral axis was 15.2 mm. The mean PF entry was 5.9 to 6.7 mm medial to the mean GT entry for each company's nail and was statistically distinct. No differences were observed in GT and PF entry points across manufacturers. Only 2 of 153 ideal GT entry points were lateral to the tip of the trochanter. An increased neck-shaft angle (NSA) and increased GT offset were correlated with a more medial ideal entry point. DISCUSSION: The ideal entry point for GT nails is similar across manufacturers and is medial to the tip of the greater trochanter; however, PF and GT entry sites remain distinct. During preoperative planning and when executing femoral nailing intraoperatively, it may also be important to consider the NSA and GT offset of a patient before committing to a certain entry point.

Free Vascularized Fibula Graft for Staged Reconstruction of Infected Humerus Nonunions.

OBJECTIVE: To evaluate the union rate and rate of postoperative complications in patients with septic nonunions of the humerus after a two-stage reconstruction using a free vascularized fibula graft. DESIGN: Retrospective case series. SETTING: Academic, tertiary referral center. PATIENTS/PARTICIPANTS: Adult patients with staged reconstruction for infected nonunion of the humerus with at least 2 years follow-up after vascularized fibula graft transfer. INTERVENTION: First, infected nonunion debridement with antibiotic spacer and external fixator placement. After antimicrobial treatment, free vascularized fibula transfer with internal fixation. MAIN OUTCOME MEASUREMENTS: Time to union, pain, affected extremity range of motion, and function. RESULTS: 10 patients with septic humerus nonunion treated with staged reconstruction using a free vascularized fibula graft, with a mean follow-up of 32.3 months were included. After the two-stage reconstruction using a free fibula, radiographic union was achieved in 6/10 patients, with a mean time to union of 19.9 weeks. The remaining 4 patients required an additional procedure with graft augmentation and/or implant revision. After the revision procedure, union was noted in 3/4 patients, 21 weeks postoperatively. Mean patient visual analog scale pain scores improved from 5.8 preoperatively to 0.9 at final follow-up ( P = 0.02). Postoperatively, mean elbow flexion was 110 ± 20 degrees and extension 15 ± 7.5 degrees. CONCLUSION: A two-stage reconstruction using a free fibula graft can be used in patients with septic nonunions of the humerus in the setting of multiple failed prior surgeries and compromised local biology. Additional procedures may be needed in some to achieve final union. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A Central Collinear Start Point for Reconstruction Nailing of Femur Fractures: A Technical Trick and Case Series.

SUMMARY: Selecting the optimal entry point for reconstruction nailing is critical to avoid iatrogenic malalignment and optimize mechanical stability. In-line nailing is familiar to surgeons and desirable for its on-axis position. However, there are several potential drawbacks. We describe a modified entry point and present an accompanying clinical series emphasizing an entry point in line with the medullary canal and central on the femoral neck. This central collinear start point is anterior to the traditional piriformis start point and may obviate some of the potential drawbacks with traditional piriformis nailing.

Comparison of the Neer classification to the 2018 update of the Orthopedic Trauma Association/AO fracture classification for classifying proximal humerus fractures.

Background: The classification of fractures is necessary to ensure a reliable means of communication for clinical interaction, education and research. The Neer classification is the most commonly used classification for proximal humerus fractures. In 2018 the Orthopedic Trauma Association (OTA) and the AO Foundation provided an update to the OTA/AO Fracture Classification Scheme addressing many of the concerns about the previous versions of the classification. The objective of the present study was to evaluate the rater reliability of the 2 classifications and if the classifications subjectively better characterized the fracture patterns. Methods: X-rays and CT scans of 24 proximal humerus fractures were given to 7 independent raters for classification according to the Neer and 2018 OTA/AO classification. Both full-forms and short-forms of the classifications were tested. The Fleiss Kappa statistic was used to assess inter-rater agreement and intra-rater consistency for the 2 classifications. For each case the raters subjectively commented on how well each classification was able to characterize the fracture pattern. Results: All raters graded the 2018 OTA/AO classification as good as or better than the Neer classification for an adequate description of the fracture patterns. The short-form 2018 OTA/AO classification had the most 4 rater and 5 rater agreement cases and the second most 6 rater agreement cases. The short-form Neer classification had the second most 4 rater and 5 rater agreement cases and the most 6 rater agreement cases. The full 2018 OTA/AO had the least 4, 5, or 6 rater agreement cases of all the classification systems. Inter-rater agreement was fair for the full and short form of both the Neer and 2018 OTA/AO classification. The full and short Neer classifications together with the short 2018 OTA/AO classification had moderate intra-rater consistency, while the full 2018 OTA/AO classification only had slight intra-rater consistency. Conclusions: The 2018 OTA/AO classification is equivalent in its short-form to the Neer classification in inter-rater reliability and intra-rater consistency; and is superior in its full form for characterizing specific fracture types. The low inter-rater reliability of the full 2018 OTA/AO classification is a concern that may need to be addressed in the future.

Survey Analysis of Orthopedic Call Compensation.

We sought to determine the type, frequency, and compensation details of orthopedic call for orthopedic traumatologists. We administered a 24-question survey to all members of the Orthopaedic Trauma Association regarding the number and type of orthopedic surgeons within the call pool, frequency of call, number of hospitals covered, and compensation for weekday, weekend, holiday, and pediatric calls. A total of 105 orthopedic surgeons replied. The most common number of physicians in the call pool was 6 to 10 (42.9%), whereas the most common number of traumatologists was 0 to 5 (90.5%), with 71.4% taking call at 1 hospital. Further, 56.7% were paid separately for weekday trauma call, with the most common number of call days per week being 2. The most common compensation was $1001 to $1500 (31.6%). For weekend call, 49.5% of physicians were paid separately, with the most common number of weekends on call per year being 11 to 15 (34.3% of replies). For pediatric call, 54.3% of physicians took call, with 28.6% paid separately and 33.3% receiving $0 to $500. For holiday call, 40.2% of physicians were paid separately, with 30.8% receiving $1001 to $1500. We describe the characteristics of traumatology call. Approximately 50% of physicians (range, 28.6%-56.3%) are compensated separately for taking different forms of call (ie, weekday, weekend, holiday). [Orthopedics. 2022;45(5):293-296.].

Adaptation of the Centers for Disease Control Surgical Wound Classification System for Orthopaedic Trauma Surgery.

OBJECTIVES: To evaluate a proposed orthopaedic-specific surgical wound classification system (SWCS) and the current Centers for Disease Control (CDC) system in a series of detailed clinical vignettes and to identify the degree of satisfaction with CDC SWCS and desire for institution of an orthopaedic-specific SWCS. METHODS: Forty-five clinical vignettes and a 5-question survey were distributed to current and past members of the Orthopaedic Trauma Association's Classification Committee. Respondents were asked to provide wound class for each vignette using the CDC system and orthopaedic-specific SWCS. RESULTS: The orthopaedic-specific and CDC SWCS had interclass correlations of 0.95 and 0.91, respectively. When the systems were compared, in 34% of cases, there was no grade change; in 63% of cases, the wound was graded higher using the orthopaedic-specific SWCS. When only the procedure was changed between vignettes, wound classification was infrequently affected. There was near universal dissatisfaction with the CDC SWCS and desire for an orthopaedic-specific system. CONCLUSIONS: Both the CDC SWCS and orthopaedic-specific SWCS have excellent interobserver reliability. Incorporation of orthopaedic-specific language affects wound classification. There is low satisfaction with the current CDC SWCS and a desire exists for further development and validation of an orthopaedic-specific SWCS.

Delayed debridement of open tibia fractures beyond 24 and 48 h does not appear to increase infection and reoperation risk.

PURPOSE: Surgical debridement is critical to the treatment of open tibia fractures, although the effects of delayed debridement have not been well-established. Other factors such as Gustilo-Anderson type, prompt initiation of antibiotics, and time to definitive closure may be more predictive of infection than time to surgery. We sought to determine the effect of a prolonged delay to surgical debridement with respect to infection and reoperation rates for open tibia fractures. METHODS: All open diaphyseal tibia fractures with > 12-week follow-up were evaluated. Patient demographics, Gustilo-Anderson type, and rates of deep infection and all-cause reoperation were recorded. Patients were divided into 3 groups based on time to surgery: early (< 24 h), delayed (24-48 h), and late (> 48 h). Univariate and multivariate analyses were performed to evaluate the relationship between time to surgery, fracture type, infection, and reoperation. RESULTS: In total, 96 open tibia fractures with average follow-up of 59.3 weeks and infection rate of 13.5% were included. Infection rates for the early, delayed, and late groups were 13.3%, 17.2%, and 9.1%, respectively (p = 0.70). Reoperation rates for the early, delayed, and late groups were 29.8%, 31.0%, and 22.7%, respectively (p = 0.80). The groups did not vary in proportion of Gustilo-Anderson fracture types; infection rates between Gustilo-Anderson types were similar (p = 0.57). Type IIIA-C fractures required more reoperations than other fracture types (p = 0.01). CONCLUSION: Delayed surgical debridement of open tibia fractures did not result in greater rates of infection or reoperation. Gustilo-Anderson classification was more predictive of reoperation, with Type IIIA-C injuries having a significantly higher reoperation rate.

Radiographic detection of lateral plateau involvement in medial tibial plateau fractures (AO/OTA 41-B1.2, 1.3, 3.2 and 3.3).

PURPOSE: To assess the accuracy of radiographs in detecting the lateral plateau involvement of medial tibial plateau fractures as well as describe the impact of CT on preoperative planning for this specific fracture morphology. METHODS: Radiograph and CT imaging of patients with a Schatzker type IV tibial plateau fractures (AO/OTA 41-B1.2, B1.3 h, B2.2. B3.2, and B3.3) between January 2013 and July 2017 were reviewed by three trauma fellowship-trained orthopedic surgeons to identify fractures of the medial condyle with an intact anterolateral articular surface. RESULTS: Lateral plateau involvement was identified in 16 (37%) radiographs and 26 (61%) CT images (p = 0.051). Radiographic detection of lateral plateau involvement demonstrated a sensitivity of 62% and specificity of 100%, and radiographs were able to predict the recommendation for surgical intervention for lateral plateau involvement with a positive predictive value (PPV) of 75% and a negative predictive value (NPV) of 60% compared to recommendations based on CT imaging. Radiographs predicted a need for a separate surgical approach with PPV of 63% and NPV of 70% when compared to recommendations based on CT images. CONCLUSIONS: Radiographs are reliable in ruling in lateral plateau involvement of medial plateau fractures, but occult lateral articular extension may only be identified in CT imaging for some cases. Surgical planning may be impacted by CT imaging for this fracture morphology, but further study is warranted to evaluate the correlation between preoperative planning and clinical outcomes. LEVEL OF EVIDENCE: III.

Management of Segmental Tibial Bone Defects With a Motorized Intramedullary Bone Transport Nail: A Case Review With Follow-Up.

SUMMARY: Large segment bone defects of the tibia are challenging problems. Although caused by a wide range of conditions, tibial critical bone loss defects often require complex reconstructive plans with prolonged inability to weight-bear on the effected extremity. Reconstruction options frequently require harvesting of autograft leading to further morbidity. Distraction osteogenesis allows reconstruction of large segmental defects of the tibia while avoiding donor site morbidity. Historically, distraction osteogenesis of tibia was most reliably performed with circler ring external fixation. This process allowed early weight-bearing but unfortunately has considerable drawbacks. Negative effects include pin tract irritation and inability to wear normal clothes. The advent of the bone transport nail now allows management of tibial critical bone loss defects through distraction osteogenesis negating the need for external fixation. This new technique allows treatment of large segmental tibial defects by means of distraction osteogenesis with an all-internal device avoiding the negative effects of external fixation while simultaneously allowing early weight-bearing.

Large Individual Bilateral Differences in Tibial Torsion Impact Accurate Contralateral Templating and the Evaluation of Rotational Malalignment.

OBJECTIVE: To determine individual bilateral differences (IBDs) in tibial torsion in a diverse population. METHODS: Computed tomography scans of uninjured bilateral tibiae were used to determine tibial torsion and IBDs in torsion using 4 measurement methods. Age, sex, and self-identified race/ethnicity were also recorded for each subject. Mean tibial torsion and IBDs in torsion were compared in the overall cohort and when stratified by sex and race/ethnicity. Simple and multiple linear regression models were used to correlate demographic variables with tibial torsion and IBDs in torsion. RESULTS: One hundred ninety-five patients were evaluated. The mean tibial torsion was 27.5 ± 8.3 degrees (range -3 to 47.5 degrees). The mean IBD in torsion was 5.3 ± 4.0 degrees (range 0-23.5 degrees, P < 0.001). 12.3% of patients had IBDs in torsion of ≥10 degrees. In the regression analysis, patients who identified as White had greater average torsion by 4.4 degrees compared with Hispanic/Latinx patients (P = 0.001), whereas age and sex were not significantly associated with absolute torsion. Demographics were not associated with significant differences in IBDs in torsion. CONCLUSIONS: Tibial torsion varies considerably and individual side-to-side differences are common. Race/ethnicity was associated with differences in the magnitude of tibial torsion, but no factors were associated with bilateral differences in torsion. The results of this study may be clinically significant in the context of using the uninjured contralateral limb to help establish rotational alignment during medullary nail stabilization of diaphyseal tibia fractures. In addition, these findings should be considered in the evaluation of tibia rotational malalignment. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Treatment of tibial plateau fractures with a novel fenestrated screw system for delivery of bone graft substitute.

PURPOSE: The purpose of this study was to describe the incidence of subsidence in patients with AO/OTA 41 (tibial plateau) fractures which were repaired with a novel fenestrated screw system to used to deliver CaPO4 bone substitute material to fill the subchondral void and support the articular reduction. METHODS: Patients with unicondylar and bicondylar tibial plateau fractures were treated according to the usual technique of two surgeons. After fixation, the Zimmer Biomet N-Force Fixation System®, a fenestrated screw that allows for the injection of bone substitute was placed and used for injection of the proprietary calcium phosphate bone graft substitute into the subchondral void. For all included patients, demographic information, operative data, radiographs, and clinic notes were reviewed. Patients were considered to have articular subsidence if one or more of two observations were made when comparing post-operative to their most recent clinic radiographs: > 2 mm change in the distance between the screw and the lowest point of the tibial plateau, > 2 mm change in the distance between the screw and the most superior aspect of the plate. Data were analyzed to determine if there were any identifiable risk factors for complication, reoperation, or subsidence using logistic regression. Statistical significance was set at p < 0.05. RESULTS: 34 patients were included with an average follow-up of 32.03 ± 22.52 weeks. There were no overall differences between height relative to the medial plateau or the plate. Two patients (5.9%) had articular subsidence. Six patients (15.2%) underwent reoperation, two (6%) for manipulations under anaesthesia due to arthrofibrosis, and four (12%) due to infections. There were 6 (19%) total infections as 2 were superficial and required solely antibiotics. One patient had early failure. CONCLUSION: Use of a novel fenestrated screw system for the delivery of CaPO4 BSM results in articular subsidence and complication rates similar to previously published values and appears to be a viable option for addressing subchondral defects in tibial plateau fractures. LEVEL OF EVIDENCE: IV.