Aims. Several previously identified patient-, injury-, and treatment-related factors are associated with the development of nonunion in distal femur fractures. However, the predictive value of these factors is not well defined. We aimed to assess the predictive ability of previously identified risk factors in the development of nonunion leading to secondary surgery in distal femur fractures. Methods. We conducted a retrospective cohort study of adult patients with traumatic distal femur fracture treated with lateral locking plate between 2009 and 2018. The patients who underwent secondary surgery due to fracture healing problem or plate failure were considered having nonunion. Background knowledge of risk factors of distal femur fracture nonunion based on previous literature was used to form an initial set of variables. A logistic regression model was used with previously identified patient- and injury-related variables (age, sex, BMI, diabetes, smoking, periprosthetic fracture, open fracture, trauma energy, fracture zone length, fracture comminution, medial side comminution) in the first analysis and with treatment-related variables (different surgeon-controlled factors, e.g. plate length, screw placement, and proximal fixation) in the second analysis to predict the nonunion leading to secondary surgery in distal femur fractures. Results. We were able to include 299 fractures in 291 patients. Altogether, 31/299 fractures (10%) developed nonunion. In the first analysis, pseudo-R. 2. was 0.27 and area under the receiver operating characteristic curve (AUC) was 0.81. BMI was the most important variable in the prediction. In the second analysis, pseudo-R. 2. was 0.06 and AUC was 0.67. Plate length was the most important variable in the prediction. Conclusion. The model including patient- and injury-related factors had moderate fit and predictive ability in the prediction of distal femur fracture nonunion leading to secondary surgery. BMI was the most important variable in prediction of nonunion. Surgeon-controlled factors had a minor role in prediction of nonunion. Cite this article: Bone Jt Open 2023;4(8):584–593

Aims. This study assessed the impact of COVID-19 on hip and distal femur fracture patient outcomes across three successive UK lockdown periods over one year. Methods. A single-centre retrospective cohort study was performed at an acute NHS Trust. Hip and distal femur fracture patients admitted within the first month from each of the three starting dates of each national lockdown were included and compared to a control group in March 2019. Data were collected as per the best practice tariff outcomes including additional outcomes as required. Data collection included COVID-19 status, time to theatre, 30-day mortality, presence of acute kidney injury (AKI) and pneumonia, and do not attempt cardiopulmonary resuscitation (DNACPR) status. Data were analyzed using an independent-samples t-test or chi-squared test with Fisher’s exact test where applicable. A p-value of < 0.05 was considered statistically significant. Results. A total of 95 patients during the pandemic were included and 20 were COVID-positive. Patients experienced a statistically significant increase in time to theatre in Lockdown 1 compared to 2019 (p = 0.039) with a decrease with successive lockdown periods by Lockdown 3. The 30-day mortality increased from 8.8% in 2019 to 10.0% to 14.8% in all lockdown periods. COVID-positive patient mortality was 30.0% (p = 0.063, odds ratio (OR) = 4.43 vs 2019). The rates of AKI and pneumonia experienced were higher for patients during the pandemic. The highest rates were experienced in COVID-positive patients, with 45.0% of patients with AKI versus 27.0% in 2019 (p = 0.38, OR = 1.80), and 50.0% of patients diagnosed with pneumonia versus 16.2% in 2019 (p = 0.0012, OR = 5.17). The percentage of patients with a DNACPR increased from 30.0% in 2019 to 60.7% by Lockdown 3 (p = 0.034, OR = 3.61). Conclusion. COVID-positive hip and distal femur fracture patients are at a higher risk of mortality due to AKI and pneumonia. Patient outcomes have improved with successive lockdowns to pre-pandemic levels. Cite this article: Bone Jt Open 2021;2(12):1017–1026

Introduction. Distal femur fracture fixation in elderly presents significant challenges due to osteoporosis and associated comorbidities. There has been an evolution in the management of these fractures with a description of various surgical techniques and fixation methods; however, currently, there is no consensus on the standard of care. Non-union rates of up to 19% and mortality rates of up to 26 % at one year have been reported in the literature. Delay in surgery and delay in mobilisation post-operatively have been identified as two main factors for high rate of mortality. As biomechanical studies have proved better stability with dual plating or nail-plate combination, a trend has been shifting for past few years towards rigid fixation to allow early mobilisation. Our study aims to compare outcomes of distal femur fractures managed with either single plate (SP), dual plating (DP) or nail-plate construct (NP). Methods. A retrospective review of patients aged above 65 years with distal femur fractures (both native and peri-prosthetic) who underwent surgical management between June 2020 and May 2023 was conducted. Patients were divided into three groups based on mode of fixation - single plate or dual plating or nail-plate construct. AO/OTA classification was used for non-periprosthetic, and Unified classification system (UCS) was used for periprosthetic fractures. Data on patient demographics, fracture characteristics, surgical details, postoperative complications, re-operation rate, radiological outcomes and mortality rate were evaluated. Primary objective was to compare re-operation rate and mortality rate between 3 groups at 30 days, 6 months and at 1 year. Results. A cohort of 32 patients with distal femur fractures were included in this study. 91% were females and mean age was 80.97 (range 68–97). 18 (53%) were non-periprosthetic fracture and 14 (47%) were periprosthetic fractures.18 patients underwent single plate fixation (AO/OTA 33A – 8, 33B/C – 2, UCS V3B – 5, V3C – 3),10 patients had dual plate fixation (AO/OTA 33A – 1, 33B/C – 4, UCS V3B – 3, V3C – 2) and 4 patients underwent nail-plate combination fixation (AO/OTA 33A – 4). 70.5% patients had surgery within 36 hours of admission and 90% within 48 hours. Analysis showed no re-operation at 30 days, 6 months in all 3 groups. At 1 year one patient had re-operation in dual-plating periprosthetic group (Distal femur replacement done for failed fixation). Three patients (16%) in single plate group had re-operation at 2 years (2 for peri-implant fracture and 1 for infection). None of the patients treated with Nail-plate combination had re-operation. Mortality rate at 30 days was 0% in among all the 3 groups. At 6 months, it was 16% in single plate group and 0% in DP and NP groups at 6 months and at 1 year mortality rate was 27% in SP group, 10% in DP and 0% in NP group. Combined mortality rate was 0% at 30 days, 9% at 6 months and 18.7% at one year. Conclusion. Our analysis provides insights into fixation methods of distal femur fractures in elderly patients. We conclude that a lower re-operation rate and mortality rate can be achieved with early surgery and rigid fixation with either dual plating or nail-plate construct to allow early mobilisation. Further prospective studies are warranted to confirm these findings and guide the selection of optimal surgical strategies for these challenging fractures

Aims. The purpose of this study was to compare reoperation and revision rates of double plating (DP), single plating using a lateral locking plate (SP), or distal femoral arthroplasty (DFA) for the treatment of periprosthetic distal femur fractures (PDFFs). Methods. All patients with PDFF primarily treated with DP, SP, or DFA between 2008 and 2022 at a university teaching hospital were included in this retrospective cohort study. The primary outcome was revision surgery for failure following DP, SP, or DFA. Secondary outcome measures included any reoperation, length of hospital stay, and mortality. All basic demographic and relevant implant and injury details were collected. Radiological analysis included fracture classification and evaluation of metaphyseal and medial comminution. Results. A total of 111 PDFFs (111 patients, median age 82 years (interquartile range (IQR) 75 to 88), 86% female) with 32 (29%) Su classification 1, 37 (34%) Su 2, and 40 (37%) Su 3 fractures were included. The median follow-up was 2.5 years (IQR 1.2 to 5.0). DP, SP, and DFA were used in 15, 66, and 30 patients, respectively. Compared to SP, patients treated with DP were more likely to have metaphyseal comminution (47% vs 14%; p = 0.009), to be low fractures (47% vs 11%; p = 0.009), and to be anatomically reduced (100% vs 71%; p = 0.030). Patients selected for DFA displayed comparable amounts of medial/metaphyseal comminution as those who underwent DP. At a minimum follow-up of two years, revision surgery for failure was performed in 11 (9.9%) cases at a median of five months (IQR 2 to 9): 0 DP patients (0%), 9 SP (14%), and 2 DFA (6.7%) (p = 0.249). Conclusion. Using a strategy of DP fixation in fractures, where the fracture was low but there was enough distal bone to accommodate locking screws, and where there is metaphyseal comminution, resulted in equivalent survival free from revision or reoperation compared to DFA and SP fixation. Cite this article: Bone Jt Open 2024;5(6):489–498

Aims. Postoperative malalignment of the femur is one of the main complications in distal femur fractures. Few papers have investigated the impact of intraoperative malalignment on postoperative function and bone healing outcomes. The aim of this study was to investigate how intraoperative fracture malalignment affects postoperative bone healing and functional outcomes. Methods. In total, 140 patients were retrospectively identified from data obtained from a database of hospitals participating in a trauma research group. We divided them into two groups according to coronal plane malalignment of more than 5°: 108 had satisfactory fracture alignment (< 5°, group S), and 32 had unsatisfactory alignment (> 5°, group U). Patient characteristics and injury-related factors were recorded. We compared the rates of nonunion, implant failure, and reoperation as healing outcomes and Knee Society Score (KSS) at three, six, and 12 months as functional outcomes. We also performed a sub-analysis to assess the effect of fracture malalignment by plates and nails on postoperative outcomes. Results. The rates of nonunion and reoperation in group U were worse than those in group S (25.0% vs 14.3%; 15.6% vs 5.6%), but the differences were not significant (p = 0.180 and p = 0.126, respectively). Mean KSS in group U at all follow-up periods was significantly worse that in group S (75.7 (SD 18.8) vs 86.0 (SD 8.7); p < 0.001; 78.9 (SD 17.2) vs 89.1 (SD 9.8); p < 0.001; 85.0 (SD 11.9) vs 91.1 (SD 7.2); p = 0.002, respectively). In the sub-analysis of plates, mean KSS was significantly worse in group U at three and six months. In the sub-analysis of nails, the rate of reoperation was significantly higher in group U (28.6% vs 5.8%; p = 0.025), and mean KSS at six and 12 months was significantly worse in Group U. Conclusion. To obtain good postoperative functional results, intraoperative alignment of the coronal plane should be accurately restored to less than 5°. Cite this article: Bone Jt Open 2022;3(2):165–172

Aims. Endoprosthetic reconstruction with a distal femoral arthroplasty (DFA) can be used to treat distal femoral bone loss from oncological and non-oncological causes. This study reports the short-term implant survivorship, complications, and risk factors for patients who underwent DFA for non-neoplastic indications. Methods. We performed a retrospective review of 75 patients from a single institution who underwent DFA for non-neoplastic indications, including aseptic loosening or mechanical failure of a previous prosthesis (n = 25), periprosthetic joint infection (PJI) (n = 23), and native or periprosthetic distal femur fracture or nonunion (n = 27). Patients with less than 24 months’ follow-up were excluded. We collected patient demographic data, complications, and reoperations. Reoperation for implant failure was used to calculate implant survivorship. Results. Overall one- and five-year implant survivorship was 87% and 76%, respectively. By indication for DFA, mechanical failure had one- and five-year implant survivorship of 92% and 68%, PJI of 91% and 72%, and distal femur fracture/nonunion of 78% and 70% (p = 0.618). A total of 37 patients (49%) experienced complications and 27 patients (36%) required one or more reoperation. PJI (n = 16, 21%), aseptic loosening (n = 9, 12%), and wound complications (n = 8, 11%) were the most common complications. Component revision (n = 10, 13.3%) and single-stage exchange for PJI (n = 9, 12.0 %) were the most common reoperations. Only younger age was significantly associated with increased complications (mean 67 years (SD 9.1)) with complication vs 71 years (SD 9.9) without complication; p = 0.048). Conclusion. DFA is a viable option for distal femoral bone loss from a range of non-oncological causes, demonstrating acceptable short-term survivorship but with high overall complication rates. Cite this article: Bone Jt Open 2022;3(3):173–181

Introduction. The incidence of distal femoral fractures amongst elderly patients is likely to rise due to increased life expectancy. This study reports on the outcome of a series of distal femoral fractures treated by retrograde femoral nailing and then to compare the results for these patients with a series of patients with a proximal femoral fracture. Materials and/Methods. In this longitudinal cohort study, 36 patients with extra-articular distal femoral fractures were treated with a solid retrograde femoral nail. Data was collected prospectively and then compared to proximal femoral fractures (2426) treated by the same surgeon treated over the same time period. Results. Within the distal femoral group 97% of the patients were female, with a mean age of 81 years. The mean length of hospital stay amongst the distal femoral group was slightly higher (19 days) compared to the proximal femoral group (18 days). All the post-operative complications were higher amongst the distal femoral group which included deep vein thrombosis 8% vs 2%, pneumonia 5% vs 3%, superficial wound infection 5% vs 3% and deep wound infection 2% vs 1%. 5% of patients in the proximal femoral group required revision surgery whereas none in the distal femoral group did. The survival analysis curve indicated to an increased trend in mortality amongst the distal femoral group however due to the small sample size this did not reach statistical significance. Conclusions. Our study shows that there is a significant morbidity and mortality amongst patients who have sustained a distal femoral fracture. Given the significant risk that elderly patients have we propose that distal femoral fractures should be treated with prompt surgical fixation with an emphasis on early rehabilitation and safe discharge

Helical plates potentially bypass the medial neurovascular structures of the thigh. Recently, two plate designs (90°- and 180°-helix) proved similar biomechanically behaviour compared to straight plates. Aims of this study were: (1) Feasibility of MIPO-technique with 90°- and 180°-helical plates on the femur, (2) Assessment of distances to adjacent anatomical structures at risk, (3) Comparison of these distances to using medial straight plates instead, (4) Correlation of measurements performed in anatomic dissection with CT-angiography.

MIPO was performed in ten cadaveric femoral pairs using either a 90°-helical 14-hole-LCP (Group1) or a 180°-helical 15-hole-LCP-DF (Group2). CT angiography was used to evaluate the distances between the plates and the femoral arteries as well as the distances between the plates and the perforators. Subsequently, the specimens were dissected, and the distances were determined again manually. Finally, all helical plates were removed, and all measurements were repeated after application of straight medial plates (Group3).

Closest overall distances between plates and femoral arteries were 15 mm (11 − 19 mm) in Group1, 22 mm (15 − 24 mm) in Group2 and 6 mm (1 − 8 mm) in Group3 with a significant difference between Group1 and Group3 (p < 0.001). Distances to the nearest perforators were 24 mm (15 − 32 mm) in Group1 and 2 mm (1 − 4 mm) in Group2. Measurement techniques (visual after surgery and CT-angiography) demonstrated a strong correlation of r² = 0.972 (p < 0.01).

MIPO with 90°- and 180°-helical plates is feasible and safe. Attention must be paid to the medial neurovascular structures with 90°-helical implants and to the proximal perforators with 180°-helical implants. Helical implants can avoid medial neurovascular structures compared to straight plates although care must be taken during their distal insertion. Measurements during anatomical dissection correlate with CT-angiography.

Purpose: surgical fixation distal femoral fractures has been associated withnonunion and varus collapse. the soft tissue stripping esulted from this fracture and caused by the surgical approach have been factorassociated with delayed union and infection. the limited soft tissue exposure has been lauded as a solution to this fracture. however, it has occurred with new fixation as well (locked plate) this study is an attempt to look at the fixation from the surgical approach prospective. does the liss system improve the results of this difficult fracture? is there truly a difference in the outcome of this fracture utilizing the locked plate system or the percieved difference due to surgical mini invasive approach. Method: one hundred and forty patientswere screened, and only 53 were randomized and treated in six academic centers over five years. all c3 fractures were excluded from the study as they were felt not to be treatable by the dcs device, but they were treated and fixed appropiately. thirty five females and 18 males were included and appropiately randomized. Results: fifty three patients were randomized, 28 had the liss implant while 25 had the dcs utilized. there were three nonunions in the liss group, plus two patients required an early reoperation in the early post operative periods ( second – fifth post op. day) due to an early loss of reduction. further more, one patient developed a knee arthrofibrosis that required arthroscopic joint release with subsequent implant failure. that necessiated a reoperation. in the dcs group there was only one nonunion, that required reoperation. this translated into reoperation rate of 21%in the liss group compared to 4% with dcs. Conclusion: this prospective multicenter randomized trial showeda significant difference when comparing the liss device to the dcs system in minimal invasive approach of distal femoral fractures fixation

This multi-center randomized prospective trial examined fixation for distal femoral fractures by standardizing the surgical approach as minimally invasive. Fifty three patients at six Canadian trauma centers were randomized via the Lead Centre (Halifax Infirmary, Dal-housie University, Halifax, CANADA) into 2 groups of 28 LISS and 25 DCS respectively. The AO C3 group was excluded from randomization. In the LISS group, three fractures went on to non-union and two fractures were complicated by early loss of fixation. A further LISS patient had removal of all metalwork when removal of individual prominent screws proved impossible due to cold-welding. In the DCS group, one fracture was complicated by non-union. The difference between the two groups proved very statistically significant. (P< 0.05). In this trial, the LISS proved more technically demanding and a higher re-operation rate was evident. At the Lead Centre, the LISS has been abandoned in favor of the DCS or LCP Condylar Plate performed via a minimally invasive approach

The management of periprosthetic distal femur fractures is an issue of increasing importance for orthopaedic surgeons. Because of the expanding indications for total knee arthroplasty (TKA) and an aging population with increasingly active lifestyles there has been a corresponding increase in the prevalence of these injuries. The management of these fractures is often complex because of issues with obtaining fixation around implants and dealing with osteopenic bone or compromised bone stock. In addition, these injuries frequently occur in frail, elderly patients, and the early restoration of function and ambulation is critical in these patients. There remains substantial controversy with respect to the optimal treatment of periprosthetic distal femur fractures, with some advocating for Locked Plating (LP), others Retrograde Intramedullary Nailing (RIMN) and finally those who advocate for Distal Femoral Replacement (DFR). The literature comparing these treatments, has been infrequent, and commonly restricted to single-center studies. The purpose of this study was to retrospectively evaluate a large series of operatively treated periprosthetic distal femur fractures from multiple centers and compare treatment strategies. Patients who were treated operatively for a periprosthetic distal femur fracture at 8 centers across North America between 2003 and 2018 were retrospectively identified. Baseline characteristics, surgical details and post-operative clinical outcomes were collected from patients meeting inclusion criteria. Inclusion criteria were patients aged 18 and older, any displaced operatively treated periprosthetic femur fracture and documented 1 year follow-up. Patients with other major lower extremity trauma or ipsilateral total hip replacement were excluded. Patients were divided into 3 groups depending on the type of fixation received: Locked Plating, Retrograde Intramedullary Nailing and Distal Femoral Replacement. Documented clinical follow-up was reviewed at 2 weeks, 3 months, 6 months and 1 year following surgery. Outcome and covariate measures were assessed using basic descriptive statistics. Categorical variables, including the rate of re-operation, were compared across the three treatment groups using Fisher Exact Test. In total, 121 patients (male: 21% / female: 79%) from 8 centers were included in our analysis. Sixty-seven patients were treated with Locked Plating, 15 with Retrograde Intramedullary Nailing, and 39 were treated with Distal Femoral Replacement. At 1 year, 64% of LP patients showed radiographic union compared to 77% in the RIMN group (p=0.747). Between the 3 groups, we did not find any significant differences in ambulation, return to work and complication rates at 6 months and 1 year (Table 1). Reoperation rates at 1 year were 27% in the LP group (17 reoperations), 16% in the DFR group (6 reoperations) and 0% in the RIMN group. These differences were not statistically significant (p=0.058). We evaluated a large multicenter series of operatively treated periprosthetic distal femur fractures in this study. We did not find any statistically significant differences at 1 year between treatment groups in this study. There was a trend towards a lower rate of reoperation in the Retrograde Intramedullary Nailing group that should be evaluated further with prospective studies. For any figures or tables, please contact the authors directly

Abstract. Introduction. Distal Femoral Fractures around a Total Knee Replacement have a reported incidence of 0.25–2.3% of primary TKRs. Literature suggests that these fractures have high complication rates such as non union and revision. Methodology. A retrospective case note review was undertaken of all patients who sustained a distal femoral fracture around a TKR from April 2014-April 2021. Data parameters collected included patient demographics, classification of fracture, management, post op mobility, fracture union and mortality. Results. 52 distal femoral fractures were recorded, out of which 5 patients had bilateral fractures. The average age was 83.6 years (61–101). 41 fractures were managed operatively with 61% undergoing ORIF, 37% undergoing Distal Femoral Replacement & 2% undergoing a retrograde IM Nail. The median LOS was 22 days (11–85) for patients treated with DFR versus 10 (3–75) for those undergoing an ORIF. 60% of DFR patients were discharged home compared to 56% of those who underwent an ORIF. All the DFR patients were FWB post op compared to ORIF 24%. Conclusion. Over a 7 year study period, 52 distal femoral fractures were reviewed. Despite FWB status post op, patients undergoing a DFR had a longer length of stay and less were discharged home compared to the ORIF group. Given the cost of a distal femoral replacement (£4485-6500) compared to £212-297 for a locking plate, in order to get patients FWB post operatively potentially dual plating (medial and lateral) may need to be considered if the fracture is amenable to improve stability & allow FWB

With an aging population and increase in total knee arthroplasty, periprosthetic distal femur fractures (PDFFs) have increased. The differences between these fractures and native distal femur fractures (NDFF) have not been comprehensively investigated. The purpose of this study was to compare the demographic, fracture, and treatment details of PDFFs compared to NDFFs. A retrospective study of patients ≥ 18 years old who underwent surgical treatment for either a NDFF or a PDFF from 2010 to 2020 at a level 1 trauma center was performed. Demographics, AO/OTA fracture classification, quality of reduction, fixation constructs, and unplanned revision reoperation were compared between PDFF patients and NDFF patients using t-test and Fisher's exact test. 209 patients were identified with 70 patients having a PDFF and 139 patients having a NDFF. Of note, 48% of NDFF had a concomitant fracture of the ipsilateral knee (14%) or tibial plateau (15%). The most common AO/OTA classification for PDFFs was 33A3.3 (71%). NDFFs had two main AO/OTA classifications of 33C2.2 (28%) or 33A3.2. (25%). When controlling for patient age, bone quality, fracture classification, and fixation, the PDFF group had increased revision reoperation rate compared to NDFF (P < 0.05). PDFFs tend to occur in elderly patients with low bone quality, have complete metaphyseal comminution, and be isolated; whereas, NDFF tend to occur in younger patients, have less metaphyseal comminution, and be associated with other fractures. When controlling for variables, PDFF are at increased risk of unplanned revision reoperation. Surgeons should be aware of these increased risks in PDFFs and future research should focus on these unique fracture characteristics to improve outcomes

Introduction and Objective. Distal femoral fractures are commonly treated with a straight plate fixed to the lateral aspects of both proximal and distal fragments. However, the lateral approach may not always be desirable due to persisting soft-tissue or additional vascular injury necessitating a medial approach. These problems may be overcome by pre-contouring the plate in helically shaped fashion, allowing its distal part to be fixed to the medial aspect of the femoral condyle. The objective of this study was to investigate the biomechanical competence of medial femoral helical plating versus conventional straight lateral plating in an artificial distal femoral fracture model. Materials and Methods. Twelve left artificial femora were instrumented with a 15-hole Locking Compression Plate – Distal Femur (LCP-DF) plate, using either conventional lateral plating technique with the plate left non-contoured, or the medial helical plating technique by pre-contouring the plate to a 180° helical shape and fixing its distal end to the medial femoral condyle (n=6). An unstable extraarticular distal femoral fracture was subsequently simulated by means of an osteotomy gap. All specimens were tested under quasi-static and progressively increasing cyclic axial und torsional loading until failure. Interfragmentary movements were monitored by means of optical motion tracking. Results. Initial axial stiffness was significantly higher for helical (185.6±50.1 N/mm) versus straight (56.0±14.4) plating, p<0.01. However, initial torsional stiffness in internal and external rotation remained not significantly different between the two fixation techniques (helical plating:1.59±0.17 Nm/° and 1.52±0.13 Nm/°; straight plating: 1.50±0.12 Nm/° and 1.43±0.13Nm/°), p≥0.21. Helical plating was associated with significantly higher initial interfragmentary movements under 500 N static compression compared to straight plating in terms of flexion (2.76±1.02° versus 0.87±0.77°) and shear displacement under 6 Nm static rotation in internal (1.23±0.28° versus 0.40±0.42°) and external (1.21±0.40° versus 0.57±0.33°) rotation, p≤0.01. In addition, helical plating demonstrated significantly lower initial varus/valgus deformation than straight plating (4.08±1.49° versus 6.60±0.47°), p<0.01. Within the first 10000 cycles of dynamic loading, helical plating revealed significantly bigger flexural movements and significantly lower varus/valgus deformation versus straight plating, p=0.02. No significant differences were observed between the two fixation techniques in terms of axial and shear displacement, p≥0.76. Cycles to failure was significantly higher for helical plating (13752±1518) compared to straight plating (9727±836), p<0.01. Conclusions. Although helical plating using a pre-contoured LCP-DF was associated with higher shear and flexion movements, it demonstrated improved initial axial stability and resistance against varus/valgus deformation compared to straight lateral plating. Moreover, helical plate constructs demonstrated significantly improved endurance to failure, which may be attributed to the less progressively increasing lever bending moment arm inherent to this novel fixation technique. From a biomechanical perspective, helical plating may be considered as a valid alternative fixation technique to standard straight lateral plating of unstable distal femoral fractures

The objective of this study was to use patient-specific finite element modeling to measure the 3D interfragmentary strain environment in clinically realistic fractures. The hypothesis was that in the early post-operative period, the tissues in and around the fracture gap can tolerate a state of strain in excess of 10%, the classical limit proposed in the Perren strain theory. Eight patients (6 males, 2 females; ages 22–95 years) with distal femur fractures (OTA/AO 33-A/B/C) treated in a Level I trauma center were retrospectively identified. All were treated with lateral bridge plating. Preoperative computed tomography scans and post-operative X-rays were used to create the reduced fracture models. Patient-specific materials properties and loading conditions (20%, 60%, and 100% body weight (BW)) were applied following our published method.[1]. Elements with von Mises strains >10% are shown in the 100% BW loading condition. For all three loading scenarios, as the bridge span increased, so did the maximum von Mises strain within the strain visualization region. The average gap closing (Perren) strain (mean ± SD) for all patient-specific models at each body weight (20%, 60%, and 100%) was 8.6% ± 3.9%, 25.8% ± 33.9%, and 39.3% ± 33.9%, while the corresponding max von Mises strains were 42.0% ± 29%, 110.7% ± 32.7%, and 168.4% ± 31.9%. Strains in and around the fracture gap stayed in the 2–10% range only for the lowest load application level (20% BW). Moderate loading of 60% BW and above caused gap strains that far exceeded the upper limit of the classical strain rule (<10% strain for bone healing). Since all of the included patients achieved successful unions, these findings suggest that healing of distal femur fractures may be robust to localized strains greater than 10%

Introduction. Distal femur fractures have traditionally been stabilized with either lateral locking plate or retrograde intramedullary nail. Dual-plates and nail-plate combination fixation have the theoretical biomechanical advantage, faster union and allows patients to weight bear immediately. The aim of this study is to compare single vs combination fixation, and evaluate outcomes and complications. Method. We retrospectively reviewed all patients over 60, admitted to Christchurch Hospital, between 1st Jan 2016 and 31st Dec 2022, with an AO 33A/33B/33C distal femur fracture. Patient demographics, fracture characteristics, operation details, and follow up data were recorded. Primary outcomes are union rate, ambulatory status at discharge, and surgical complications. Secondary outcomes include quality of reduction, operation time and rate of blood transfusions. Results. 114 patients were included. (92 single fixation, 22 combination fixation). Baseline demographic data and fracture characteristics did not differ between the cohorts. There was no difference in the rate of union or time to union between the two cohorts. Combination fixation patients were allowed to weight-bear as tolerated significantly more than single fixation patients (50% vs 18.9%, p=0.003). There was no difference in length of hospital stay, transfusion, complication and mortality rates. Medial translation of the distal articular block was significantly lower in the combination fixation cohort (1.2% vs 3.4%, p=0.021). Operation time was significantly longer in the combination fixation cohort (183mins vs 134mins, p<0.001). Discussion. The results show no difference in achieving union or time to union, despite better quality of fracture reduction with dual fixation. This differs to previously published literature. The clear benefit of combination fixation is immediate weight-bearing. As expected, operation times were longer with combination fixation, however this did not translate to more complications. Conclusion. Combination fixation allows earlier weight bearing, at the cost of longer operation times

Introduction. Distal femur fractures around a total knee arthroplasty (TKA) are a growing problem for orthopaedic surgeons. The purpose of this study was to identify risks of reoperation for nonunion following open reduction and internal fixation of TKA periprosthetic distal femur fractures (PDFF). Method. Patients with PDFF (AO 33A-C[VB1, C1, D1], Su types 1-3) managed operatively with open reduction and internal fixation (ORIF) were retrospectively reviewed. Exclusion criteria were acute management with a distal femur replacement, less than 6 months of follow-up, and lack of injury or follow-up radiographs. The primary outcome measure was reoperation to achieve bony union. Comparisons were made between cases that did and did not require a reoperation to achieve union. Univariate analysis was used to identify factors to be analyzed in multivariate analysis to determine independent risk factors for the primary outcome. Result. A total of 77 patients met inclusion criteria. Union rate was 69/77 (89.6%). There were no differences between the groups for age, sex, BMI, comorbidities, Su classification, open injury, or mechanism of injury. Multivariate analysis identified risks for nonunion including post-operative malalignment (OR 1.41; CI 1.20-1.64; p<0.001), notching pre-operatively (OR 1.22; CI 1.04-1.42; p=0.012), presence of screws through fracture line (OR 1.28; CI 1.17-1.39; p<0.001), plate length <12 holes (OR 1.16; CI 1.02-1.33; p=0.024) and screw density greater than 0.4 (OR 2.18; CI 1.25-3.78; p=0.006). Conclusion. The reoperation rate to promote union was 10.4%. The study identified post-operative malalignment, notching pre-operatively, presence of screws through fracture line, plate length <12 holes, and proximal screw density greater than 40% as independent risk factors for nonunion

Introduction and Objective. Plating of geriatric distal femoral fractures with Locking Compression Plate Distal Femur (LCP–DF) often requires augmentation with a supplemental medial plate to achieve sufficient stability allowing early mobilization. However, medial vital structures may be impaired by supplemental medial plating using a straight plate. Therefore, a helically shaped medial plate may be used to avoid damage of these structures. Aim of the current study was to investigate the biomechanical competence of augmented LCP–DF plating using a supplemental straight versus helically shaped medial plate. Materials and Methods. Ten pairs of human cadaveric femora with poor bone quality were assigned pairwise for instrumentation using a lateral anatomical 15-hole LCP–DF combined with a medial 14-hole LCP, the latter being either straight or manually pre-contoured to a 90-degree helical shape. An unstable distal femoral fracture AO/OTA 33–A3 was simulated by means of osteotomies. All specimens were biomechanically tested under non-destructive quasi-static and destructive progressively increasing combined cyclic axial and torsional loading in internal rotation, with monitoring by means of optical motion tracking. Results. Initial axial stiffness and torsional stiffness in internal and external rotation for straight double plating (548.1 ± 134.2 N/mm, 2.69 ± 0.52 Nm/° and 2.69 ± 0.50 Nm/°) was significantly higher versus helical double plating (442.9 ± 133.7 N/mm, 2.07 ± 0.32 Nm/° and 2.16 ± 0.22 Nm/°), p≤0.04. Initial interfragmentary axial displacement and flexural rotation under 500 N static loading were significantly smaller for straight plating (0.11 ± 0.14 mm and 0.21 ± 0.10°) versus helical plating (0.31 ± 0.14 mm and 0.68 ± 0.16°), p<0.01. However, initial varus deformation under this loading remained not significantly different between the two fixation methods (straight: 0.57 ± 0.23°, helical: 0.75 ± 0.34°), p=0.08. During dynamic loading, within the course of the first 4000 cycles the movements of the distal fragment in flexion were significantly bigger for helical over straight plating (1.03 ± 0.33° versus 0.40 ± 0.20°), p<0.01. However, no significant differences were observed between the two fixation methods in terms of varus, internal rotation, axial and shear displacements at the fracture site, and number of cycles to failure. Conclusions. Augmented lateral plating of unstable distal femoral fractures with use of supplemental helically shaped medial plate was associated with more elastic bone-implant construct behavior under static and dynamic loading compared to straight double plating. Both fixation methods resulted in comparable number of cycles to failure. From a biomechanical perspective, the more elastic helical double plating may be considered as useful alternative to straight plating, potentially reducing stress risers at the distal bone-implant interface due to its ameliorated damping capacities

Aims. The modified Radiological Union Scale for Tibia (mRUST) fractures score was developed in order to assess progress to union and define a numerical assessment of fracture healing of metadiaphyseal fractures. This score has been shown to be valuable in predicting radiological union; however, there is no information on the sensitivity, specificity, and accuracy of this index for various cut-off scores. The aim of this study is to evaluate sensitivity, specificity, accuracy, and cut-off points of the mRUST score for the diagnosis of metadiaphyseal fractures healing. Methods. A cohort of 146 distal femur fractures were retrospectively identified at our institution. After excluding AO/OTA type B fractures, nonunions, follow-up less than 12 weeks, and patients aged less than 16 years, 104 sets of radiographs were included for analysis. Anteroposterior and lateral femur radiographs at six weeks, 12 weeks, 24 weeks, and final follow-up were separately scored by three surgeons using the mRUST score. The sensitivity and specificity of mean mRUST score were calculated using clinical and further radiological findings as a gold standard for ultimate fracture healing. A receiver operating characteristic curve was also performed to determine the cut-off points at each time point. Results. The mean mRUST score of ten at 24 weeks revealed a 91.9% sensitivity, 100% specificity, and 92.6% accuracy of predicting ultimate fracture healing. A cut-off point of 13 points revealed 41.9% sensitivity, 100% specificity, and 46.9% accuracy at the same time point. Conclusion. The mRUST score of ten points at 24 weeks can be used as a viable screening method with the highest sensitivity, specificity, and accuracy for healing of metadiaphyseal femur fractures. However, the cut-off point of 13 increases the specificity to 100%, but decreases sensitivity. Furthermore, the mRUST score should not be used at six weeks, as results show an inability to accurately predict eventual fracture healing at this time point. Cite this article: Bone Jt Open 2021;2(10):796–805

Orthopaedic injuries in the knee are often associated with vascular injury. When these vascular injuries are missed devastating there are devastating outcomes like limb ablation. Pulse examination in these patients is not sensitive to exclude vascular injuries. That often lead to clinicians opting for Computed Tomography Angiogram (CTA) to exclude vascular. this usually leads to a burden in Radiology Department. This study aimed to evaluate the prevalence of vascular injury in patient with orthopaedic injury in the knee. The computed tomography (CT) done in patients with distal femur fracture, knee dislocation and proximal tibia fractures were retrieved from the picture archiving and comunication system (PACS). The CTs were done between June 2017 and June 2022. The computed tomography angiogram (CTA) reports were reviewed to determine cases that vascular injury. A sample size of 511 cases was collected. 386 cases were done CTA and 125 cases were not done CTA. There were 218 tibial plateau fractures, 79 knee dislocations, 72 distal metaphyseal femur fractures, 61 floating knees, 55 distal femure intraarticular and 26 proximal metaphyseal tibia fractures. The mechanisms of injury in these were gunshot, fall from standing height, fall from height, MVA, MBA, PVA and sports. Prevalance was 9.17% (47) of the total injuries in the knee. Prevalance in patients who were sent for CTA was 12.08%. Routine CTA in patients with injuries in the knee is not recomended. The use of ankle brachial index may decrease the number of CTA done