Current military conflicts are characterised by the use of the Improvised Explosive Device (IED). Improvements in personal protection, medical care and evacuation logistics have resulted in increasing numbers of casualties surviving with complex musculoskeletal injuries, often leading to life-long disability. Thus, there exists an urgent requirement to investigate the mechanism of extremity injury caused by these devices in order to develop mitigation strategies. In addition, the wounds of war are no longer restricted to the battlefield; similar injuries can be witnessed in civilian centres following a terrorist attack.

Key to mitigating such injuries is the ability to deconstruct the complexities of an explosive event into a controlled, laboratory-based environment. In this study, an anti-vehicle underbelly injury simulator, capable of recreating in the laboratory the impulse from an anti-vehicle (AV) explosion, is presented and characterised. Tests were then conducted to assess the simulator's ability to interact with human cadaveric legs. Two mounting conditions were assessed, simulating a typical seated and standing vehicle passenger using instrumented cadaveric lower limbs.

This experimental device, will now allow us (a) to gain comprehensive understanding of the load-transfer mechanisms through the lower limb, (b) to characterise the dissipating capacity of mitigation technologies, and (c) to assess the biofidelity of surrogates.

Aims

Traumatic central cord syndrome (CCS) typically follows a hyperextension injury and results in motor impairment affecting the upper limbs more than the lower, with occasional sensory impairment and urinary retention. Current evidence on mortality and long-term outcomes is limited. The primary aim of this study was to assess the five-year mortality of CCS, and to determine any difference in mortality between management groups or age.

Aims

Return to sport following undergoing total (TKA) and unicompartmental knee arthroplasty (UKA) has been researched with meta-analyses and systematic reviews of varying quality. The aim of this study is to create an umbrella review to consolidate the data into consensus guidelines for returning to sports following TKA and UKA.

The February 2024 Trauma Roundup³⁶⁰ looks at: Posterior malleolus fractures: what about medium-sized fragments?; Acute or delayed total hip arthroplasty after acetabular fracture fixation?; Intrawound antibiotics reduce the risk of deep infections in fracture fixation; Does the VANCO trial represent real world patients?; Can a restrictive transfusion protocol be effective beyond initial resuscitation?; What risk factors result in avascular necrosis of the talus?; Pre-existing anxiety and mood disorders have a role to play in complex regional pain syndrome; Three- and four-part proximal humeral fractures at ten years.

Aims

Current levels of hip fracture morbidity contribute greatly to the overall burden on health and social care services. Given the anticipated ageing of the population over the coming decade, there is potential for this burden to increase further, although the exact scale of impact has not been identified in contemporary literature. We therefore set out to predict the future incidence of hip fracture and help inform appropriate service provision to maintain an adequate standard of care.

Aims

To describe the epidemiology of acetabular fractures including patient characteristics, injury mechanisms, fracture patterns, treatment, and mortality.

Heterotopic ossification (HO) of the hip after injury to the central nervous system can lead to joint ankylosis. Surgery is usually delayed to avoid recurrence, even if the functional status is affected. We report a consecutive series of patients with HO of the hip after injury to the central nervous system who required surgery in a single, specialised tertiary referral unit. As was usual practice, they all underwent CT to determine the location of the HO and to evaluate the density of the femoral head and articular surface. The outcome of surgery was correlated with the pre-, peri- and post-operative findings.

In all, 183 hips (143 patients) were included of which 70 were ankylosed. A total of 25 peri-operative fractures of the femoral neck occurred, all of which arose in patients with ankylosed hips and were associated with intra-articular lesions in 18 and severe osteopenia of the femoral head in seven. All the intra-articular lesions were predicted by CT and strongly associated with post-operative complications.

The loss of the range of movement before ankylosis is a more important factor than the maturity of the HO in deciding the timing of surgery. Early surgical intervention minimises the development of intra-articular pathology, osteoporosis and the resultant complications without increasing the risk of recurrence of HO.

Background. Serious traumatic injury is a leading cause of death and disability globally, with the majority of survivors developing chronic pain. Methods. The aims of this study were to describe early predictors of poor long-term outcome for post-trauma pain. We conducted a prospective observational study, recruiting patients admitted to a Major Trauma Centre hospital in England within 14 days of their injuries, and followed them for 12 months. We defined a poor outcome as Chronic Pain Grade ≥ II and measured this at both 6-months and 12-months. A broad range of candidate predictors were used, including surrogates for pain mechanisms, quantitative sensory testing, and psychosocial factors. Univariate models were used to identify the strongest predictors of poor outcome, which were entered into multivariate models. Results. 124 eligible participants were recruited. At 6-months, 19 (23.2%) of 82 respondents reported a good outcome, whereas at 12-months 27 (61.4%) of 44 respondents reported a good outcome. The multivariate model for 6-months produced odds ratios for a unit increase in: number of fractures, 3.179 (0.52 to 19.61); average pain intensity, 1.611 (0.96 to 2.7); pain extent, 1.138 (0.92 to 1.41) and post-traumatic stress symptoms, 1.044 (0.10 to 1.10). At 12-months, equivalent values were: number of fractures, 1.653 (0.77 to 3.55); average pain intensity, 0.967 (0.67 to 1.40); pain extent, 1.062 (0.92 to 1.23) and post-traumatic stress symptoms, 1.025 (0.99 to 1.07). Conclusion. A poor long-term pain outcome from musculoskeletal traumatic injuries can be predicted by measures recorded within days of injury. Conflicts of interest: No conflicts of interest. Sources of funding: This study was funded by the National Institute for Health Research (NIHR) Surgical Reconstruction and Microbiology Research Centre (SRMRC)

Introduction. Reconstruction of large defect of tibia following infection is considered as one of the most difficult problem facing the orthopaedic surgeon. Amputation with modern prosthetic fitting is a salvage procedure to treat big defects, which gives a functional result with unpredictable psychological impact. Materials & Methods. Between January 2000 and January 2021, 56 patients (30 males and 26 females) with big defects following infection and post traumatic injury of the tibia were treated. The mean age of the patients at the time of surgery was 20.5 years (4–24 years). The fibula was mobilized medially to fill the defect and was fixed with Ilizarov fixator. The average size of the defects reconstructed was 18.5 cm (17–20 cm). Results. The average time for complete union was 8.6 months (range, 5–9 months). At final follow-up all patients had fully united. We found leg length discrepancy in 52 patients and that was corrected by re-lengthening of the solid new regenerate bone. Conclusions. The Ilizarov method has been shown to be an effective method of treating Tibialization of fibula for reconstruction of big tibial defects

Introduction. The purpose of this study was to examine trends in patient characteristics and clinical outcomes that occur with age as a statistical variable when performing autologous osteochondral transplantation (AOT) for the treatment of osteochondral lesions of the talus (OLT). Methods. A retrospective cohort study for AOT procedures on 78 patients from 2006 to 2019. was conducted Clinical outcomes were evaluated via FAOS scores. A multivariable linear regression was used to assess the independent factors predictive of the first post-operative FAOS after AOT. The independent variables included pre-operative FAOS, age, defect size, shoulder lesion, cystic lesion, prior traumatic injury, and history of microfracture surgery. A p-value <.05 was considered significant and 95% confidence limits (95% CL) for regression coefficient estimates (est.) were calculated. Results. 78 patients were included with a mean age of 35.5 ± 13.6years at a mean follow-up was 54.4 ± 18.9 months. The mean pre-operative FAOS was 54.3 ± 19.4 and the mean post-operative FAOS was 83.4 ± 13.6. The mean defect size was 109.3±62.4 mm2. The multivariable linear regression showed that the pre-operative FAOS was associated with a higher post-operative FAOS (est., 95% CL: 0.16, 0.012 – 0.307; p=0.034). Defect size (est., 95% CL: −0.05, −0.097 – −0.003; p=0.0358), having a shoulder lesion (est., 95% CL: −9.068, −15.448 – −2.688; p=0.006), or having a prior microfracture surgery (est., 95% CL: −7.07, −13.118 – −1.021; p=0.0226) were associated with a lower post-operative FAOS. Conclusion. Patient age was not an independent risk factor for inferior clinical outcomes after AOT for OLT. Additionally, cystic lesions, or lesions with a traumatic aetiology were not significantly associated with post-operative FAOS. Having a shoulder lesion had the largest marginal effect on post-operative FAOS. These findings provide important information for providers when counseling and selecting patients for AOT procedure for treatment of OLT

Timely and competent treatment of paediatric fractures is paramount to a healthy future working population. Anecdotal evidence suggests that children travel greater distances to obtain care compared to adults causing economic and geographic inequities. This study aims to qualify the informal regionalization of children's fracture care in Ontario. The results could inform future policy on resource distribution and planning of the provincial health care system. A retrospective cohort study was conducted examining two of the most common paediatric orthopaedic traumatic injuries, femoral shaft and supracondylar humerus fractures (SCH), in parallel over the last 10 years (2010-2020) using multiple linked administrative databases housed at the Institute for Clinical Evaluative Sciences (ICES) in Toronto, Ontario. We compared the distance travelled by these pediatric cohorts to clinically equivalent adult fracture patterns (distal radius fracture (DR) and femoral shaft fracture). Patient cohorts were identified based on treatment codes and distances were calculated from a centroid of patient home forward sortation area to hospital location. Demographics, hospital type, and closest hospital to patient were also recorded. For common upper extremity fracture care, 84% of children underwent surgery at specialized centers which required significant travel (44km). Conversely, 67% of adults were treated locally, travelling a mean of 23km. Similarly, two-thirds of adult femoral shaft fractures were treated locally (mean travel distance of 30km) while most children (84%) with femoral shaft fractures travelled an average of 63km to specialized centers. Children who live in rural areas travel on average 51km more than their adult rural-residing counterparts for all fracture care. Four institutions provide over 75% of the fracture care for children, whereas 22 institutions distribute the same case volume in adults.?. Adult fracture care naturally self-organizes with proportionate distribution without policy-directed systemization. There is an unplanned concentration of pediatric fracture care to specialized centers in Ontario placing undue burden on pediatric patients and inadvertently stresses the surgical resources in a small handful of hospitals. In contrast, adult fracture care naturally self-organizes with proportionate distribution without policy-directed systemization. Patient care equity and appropriate resource allocation cannot be achieved without appropriate systemization of pediatric fracture care

Meniscal root tears can result from traumatic injury to the knee or gradual degeneration. When the root is injured, the meniscus becomes de-functioned, resulting in abnormal distribution of hoop stresses, extrusion of the meniscus, and altered knee kinematics. If left untreated, this can cause articular cartilage damage and rapid progression of osteoarthritis. Multiple repair strategies have been described; however, no best fixation practice has been established. To our knowledge, no study has compared suture button, interference screw, and HEALICOIL KNOTLESS fixation techniques for meniscal root repairs. The goal of this study is to understand the biomechanical properties of these fixation techniques and distinguish any advantages of certain techniques over others. Knowledge of fixation robustness will aid in surgical decision making, potentially reducing failure rates, and improving clinical outcomes. 19 fresh porcine tibias with intact medial menisci were randomly assigned to four groups: 1) native posterior medial meniscus root (PMMR) (n = 7), 2) suture button (n = 4), 3) interference screw (n = 4), or 4) HEALICOIL KNOTLESS (n = 4). In 12 specimens, the PMMR was severed and then refixed by the specified group technique. The remaining seven specimens were left intact. All specimens underwent cyclic loading followed by load-to-failure testing. Elongation rate; displacement after 100, 500, and 1000 cycles; stiffness; and maximum load were recorded. Repaired specimens had greater elongation rates and displacements after 100, 500, and 1000 cycles than native PMMR specimens (p 0.05). The native PMMR showed greater maximum load than all repair techniques (p 0.05). In interference screw and HEALICOIL KNOTLESS specimens, failure occurred as the suture was displaced from the fixation and tension was gradually lost. In suture button specimens, the suture was either displaced or completely separated from the button. In some cases, tear formation and partial failure also occurred at the meniscus luggage tag knot. Native PMMR specimens failed through meniscus or meniscus root tearing. All fixation techniques showed similar biomechanical properties and performed inferiorly to the native PMMR. Evidence against significant differences between fixation techniques suggests that the HEALICOIL KNOTLESS technique may present an additional option for fixation in meniscal root repairs. While preliminary in vitro evidence suggests similarities between fixation techniques, further research is required to determine if clinical outcomes differ

Abstract. Introduction. Skeletal muscle wasting is an important clinical issue following acute traumatic injury, and can delay recovery and cause permanent functional disability particularly in the elderly. However, the fundamental mechanisms involved in trauma-induced muscle wasting remain poorly defined and therapeutic interventions are limited. Objectives. To characterise local and systemic mediators of skeletal muscle wasting in elderly patients following acute trauma. Methods. Experiments were approved by a local NHS Research Ethics Committee and all participants provided written informed consent. Vastus lateralis biopsies and serum samples were taken from human male and female patients shortly after acute trauma injury in lower limbs (n=6; mean age 78.7±4.4 y) and compared to age-matched controls (n=6; mean age 72.6±6.3 y). Atrogenes and upstream regulators (MuRF1; MAFbx; IL6, TNFα, PGC-1α) mRNA expression was assessed in muscle samples via RT-qPCR. Serum profiling of inflammatory markers (e.g. IL6, TNFα, IL1β) was further performed via multiplex assays. To determine whether systemic factors induced by trauma directly affect muscle phenotype, differentiated primary human myotubes were treated in vitro with serum from controls or trauma patients (pooled; n=3 each) in the final 24 hours of differentiation. Cells were then fixed, stained for myogenin and imaged to determine minimum ferret diameter. Statistical significance was determined at P<0.05. Results. There was an increase in skeletal muscle mRNA expression for E3 ligase MAFbx and inflammatory cytokine IL-6 (4.6 and 21.5-fold respectively; P<0.05) in trauma patients compared to controls. Expression of myogenic determination factor MyoD and regulator of mitochondrial biogenesis PGC-1α was lower in muscle of trauma patients vs controls (0.5 and 0.39-fold respectively; P<0.05). In serum, trauma patients showed increased concentrations of circulating pro-inflammatory cytokines IL-6 (14.5 vs. 0.3 pg/ml; P<0.05) and IL-16 (182.7 vs. 85.2 pg/ml; P<0.05) compared to controls. Primary myotube experiments revealed serum from trauma patients induced atrophy (32% decrease in diameter) compared to control serum-treated cells (P<0.001). Conclusion. Skeletal muscle from patients following acute trauma injury showed greater expression of atrophy and inflammatory markers. Trauma patient serum exhibited higher circulating pro-inflammatory cytokine concentrations. Primary human myotubes treated with serum from trauma patients showed significant atrophy compared to healthy serum-treated controls. We speculate a mechanism(s) acting via circulating factors may contribute to skeletal muscle pathology following acute trauma. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction. Transtibial osseointegration (TFOI) for amputees has limited but clear literature identifying superior quality of life and mobility versus a socketed prosthesis. Some amputees have knee arthritis that would be relieved by a total knee replacement (TKR). No other group has reported performing a TKR in association with TTOI (TKR+TTOI). We report the outcomes of nine patients who had TKR+TTOI, followed for an average 6.5 years. Materials & Methods. Our osseointegration registry was retrospectively reviewed to identify all patients who had TTOI and who also had TKR, performed at least two years prior. Four patients had TKR first the TTOI, four patients had simultaneous TKR+TTOI, and one patient had 1 OI first then TKR. All constructs were in continuity from hinged TKR to the prosthetic limb. Outcomes were: complications prompting surgical intervention, and changes in daily prosthesis wear hours, Questionnaire for Persons with a Transfemoral Amputation (QTFA), and Short Form 36 (SF36). All patients had clinical follow-up, but two patients did not have complete survey and mobility tests at both time periods. Results. Six (67%) were male, average age 51.2±14.7 years. All primary amputations were performed to manage traumatic injury or its sequelae. No patients died. Five patients (56%) developed infection leading to eventual transfemoral amputation 36.0±15.3 months later, and 1 patient had a single debridement six years after TTOI with no additional surgery in the subsequent two years. All patients who had transfemoral amputation elected for and received transfemoral osseointegration, and no infections occurred, although one patient sustained a periprosthetic fracture which was managed with internal fixation and implant retention and walks independently. The proportion of patients who wore their prosthesis at least 8 hours daily was 5/9=56%, versus 7/9=78% (p=.620). Even after proximal level amputation, the QTFA scores improved versus prior to TKR+TTOI, although not significantly: Global (45.2±20.3 vs 66.7±27.6, p=.179), Problem (39.8±19.8 vs 21.5±16.8, p=.205), Mobility (54.8±28.1 vs 67.7±25.0, p=.356). SF36 changes were also non-significant: Mental (58.6±7.0 vs 46.1±11.0, p=.068), Physical (34.3±6.1 vs 35.2±13.7, p=.904). Conclusions. TKR+TTOI presents a high risk for eventual infection prompting subsequent transfemoral amputation. Although none of these patients died, in general, TKR infection can lead to patient mortality. Given the exceptional benefit to preserving the knee joint to preserve amputee mobility and quality of life, it would be devastating to flatly force transtibial amputees with severe degenerative knee joint pain and unable to use a socket prosthesis to choose between TTOI but a painful knee, or preemptive transfemoral amputation for transfemoral osseointegration. Therefore, TTOI for patients who also request TKR must be considered cautiously. Given that this frequency of infection does not occur in patients who have total hip replacement in association with transfemoral osseointegration, the underlying issue may not be that linked joint replacement with osseointegrated limb replacement is incompatible, but may require further consideration of biological barriers to ascending infection and/or significant changes to implant design, surgical technique, or other yet-uncertain factors

Introduction and Objective. Up to 30% of thoracolumbar (TL) fractures are missed in the emergency room. Failure to identify these fractures can result in neurological injuries up to 51% of the casesthis article aimed to clarify the incidence and risk factors of traumatic fractures in China. The China National Fracture Study (CNFS. Obtaining sagittal and anteroposterior radiographs of the TL spine are the first diagnostic step when suspecting a traumatic injury. In most cases, CT and/or MRI are needed to confirm the diagnosis. These are time and resource consuming. Thus, reliably detecting vertebral fractures in simple radiographic projections would have a significant impact. We aim to develop and validate a deep learning tool capable of detecting TL fractures on lateral radiographs of the spine. The clinical implementation of this tool is anticipated to reduce the rate of missed vertebral fractures in emergency rooms. Materials and Methods. We collected sagittal radiographs, CT and MRI scans of the TL spine of 362 patients exhibiting traumatic vertebral fractures. Cases were excluded when CT and/or MRI where not available. The reference standard was set by an expert group of three spine surgeons who conjointly annotated (fracture/no-fracture and AO Classification) the sagittal radiographs of 171 cases. CT and/or MRI were used confirm the presence and type of the fracture in all cases. 302 cropped vertebral images were labelled “fracture” and 328 “no fracture”. After augmentation, this dataset was then used to train, validate, and test deep learning classifiers based on the ResNet18 and VGG16 architectures. To ensure that the model's prediction was based on the correct identification of the fracture zone, an Activation Map analysis was conducted. Results. Vertebras T12 to L2 were the most frequently involved, accounting for 48% of the fractures. Accuracies of 88% and 84% were obtained with ResNet18 and VGG16 respectively. The sensitivity was 89% with both architectures but ResNet18 had a significantly higher specificity (88%) compared to VGG16 (79%). The fracture zone used was precisely identified in 81% of the heatmaps. Conclusions. Our AI model can accurately identify anomalies suggestive of TL vertebral fractures in sagittal radiographs precisely identifying the fracture zone within the vertebral body

Aims. High-energy injuries can result in multiple complications, the most prevalent being infection. Vancomycin powder has been used with increasing frequency in orthopaedic trauma given its success in reducing infection following spine surgery. Additionally, large, traumatic injuries require wound coverage and management by dressings such as negative pressure wound therapy (NPWT). NPWT has been shown to decrease the ability of antibiotic cement beads to reduce infection, but its effect on antibiotic powder is not known. The goal of this study was to determine if NPWT reduces the efficacy of topically applied antibiotic powder. Methods. Complex musculoskeletal wounds were created in goats and inoculated with a strain of Staphylococcus aureus modified to emit light. Six hours after contaminating the wounds, imaging, irrigation, and debridement and treatment application were performed. Animals received either vancomycin powder with a wound pouch dressing or vancomycin powder with NPWT. Results. There were no differences in eradication of bacteria when vancomycin powder was used in combination with NPWT (4.5% of baseline) compared to vancomycin powder with a wound pouch dressing (1.7% of baseline) (p = 0.986), even though approximately 50% of the vancomycin was recovered in the NPWT exudate canister. Conclusion. The antimicrobial efficacy of the vancomycin powder was not diminished by the application of NPWT. These topical and locally applied therapies are potentially effective tools that can provide quick, simple treatments to prevent infection while providing coverage. By reducing the occurrence of infection, the recovery is shortened, leading to an overall improvement in quality of life. Cite this article: Bone Joint Res 2021;10(2):149–155

Aims. The aim of this study was to investigate whether on-demand removal (ODR) is noninferior to routine removal (RR) of syndesmotic screws regarding functional outcome. Methods. Adult patients (aged above 17 years) with traumatic syndesmotic injury, surgically treated within 14 days of trauma using one or two syndesmotic screws, were eligible (n = 490) for inclusion in this randomized controlled noninferiority trial. A total of 197 patients were randomized for either ODR (retaining the syndesmotic screw unless there were complaints warranting removal) or RR (screw removed at eight to 12 weeks after syndesmotic fixation), of whom 152 completed the study. The primary outcome was functional outcome at 12 months after screw placement, measured by the Olerud-Molander Ankle Score (OMAS). Results. There were 152 patients included in final analysis (RR = 73; ODR = 79). Of these, 59.2% were male (n = 90), and the mean age was 46.9 years (SD 14.6). Median OMAS at 12 months after syndesmotic fixation was 85 (interquartile range (IQR) 60 to 95) for RR and 80 (IQR 65 to 100) for ODR. The noninferiority test indicated that the observed effect size was significantly within the equivalent bounds of -10 and 10 scale points (p < 0.001) for both the intention-to-treat and per-protocol, meaning that ODR was not inferior to RR. There were significantly more complications in the RR group (12/73) than in the ODR group (1/79) (p = 0.007). Conclusion. ODR of the syndesmotic screw is not inferior to routine removal when it comes to functional outcome. Combined with the high complication rate of screw removal, this offers a strong argument to adopt on demand removal as standard practice of care after syndesmotic screw fixation. Cite this article: Bone Joint J 2021;103-B(11):1709–1716

Heterotopic ossification (HO) is a well-known complication of traumatic elbow injuries. The reported rates of post-traumatic HO formation vary from less than 5% with simple elbow dislocations, to greater than 50% in complex fracture-dislocations. Previous studies have identified fracture-dislocations, delayed surgical intervention, and terrible triad injuries as risk factors for HO formation. There is, however, a paucity of literature regarding the accuracy of diagnosing post-traumatic elbow HO. Therefore, the purpose of our study was to determine the inter-rater reliability of HO diagnosis using standard radiographs of the elbow at 52 weeks post-injury, as well as to report on the rate of mature compared with immature HO. We hypothesized inter-rater reliability would be poor among raters for HO formation. Prospectively collected data from a large clinical trial was reviewed by three independent reviewers (one senior orthopedic resident, one senior radiology resident, and one expert upper extremity orthopedic surgeon). Each reviewer examined anonymized 52-week post-injury radiographs of the elbow and recorded: 1. the presence or absence of HO, 2. the location of HO, 3. the size of the HO (in cm, if present), and 4. the maturity of the HO formation. Maturity was defined by consensus prior to image review and defined as an area of well-defined cortical and medullary bone outside the cortical borders of the humerus, ulna, or radius. Immature lesions were defined as an area of punctate calcification with an ill-defined cloud-like density outside the cortical borders of the humerus, ulna or radius. Data were collected using a standardized online data collection form (CognizantMD, Toronto, ON, CA). Inter-rater reliability was calculated using Fleiss’ Kappa statistic and a multivariate logistic regression analysis was performed to identify risk factors for HO formation in general, as well as mature HO at 52 weeks post injury. Statistical analysis was performed using RStudio (version1.4, RStudio, Boston, MA, USA). A total of 79 radiographs at the 52-week follow-up were reviewed (54% male, mean age 50, age SD 14, 52% operatively treated). Inter-rater reliability using Fleiss’ Kappa was k= 0.571 (p = 0.0004) indicating moderate inter-rater reliability among the three reviewers. The rate of immature HO at 52 weeks was 56%. The multivariate logistic regression analysis identified male sex as a significant risk factor for HO development (OR 5.29, 1.55-20.59 CI, p = 0.011), but not for HO maturity at 52 weeks. Age, time to surgery, and operative intervention were not found to be significant predictors for either HO formation or maturity of the lesion in this cohort. Our study demonstrates moderate inter-rater reliability in determining the presence of HO at 52 weeks post-elbow injury. There was a high rate (56%) of immature HO at 52-week follow-up. We also report the finding of male sex as a significant risk factor for post traumatic HO development. Future research directions could include investigation into possible male predominance for traumatic HO formation, as well as improving inter-rater reliability through developing a standardized and validated classification system for reporting the radiographic features of HO formation around the elbow