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

Abstract. Objectives. Catastrophic neck injuries in rugby tackling are rare (2 per 100,000 players per year) with 38% of these injuries occurring in the tackle. The aim of this study was to determine the primary mechanism of cervical spine injury during rugby tackling and to highlight the effect of tackling technique on intervertebral joint loads. Methods. In vivo and in vitro experimental data were integrated to generate realistic computer simulations representative of misdirected tackles. MRI images were used to inform the creation of a musculoskeletal model. In vivo kinematics and neck muscle excitations were collected during lab-based staged tackling of the player. Impact forces were collected in vitro using an instrumented anthropometric test device during experimental simulations of rugby collisions. Experimental kinematics and muscle excitations were prescribed to the model and impact forces applied to seven skull locations (three cranial and four lateral). To examine the effects of technique on intervertebral joint loads the model's neck angle was altered in steps of 5° about each rotational axis resulting in a total of 1,623 experimentally informed simulations of misdirected tackles. Results. Neck flexion angles and cranial impact locations had the largest effects on maximal compression, anterior shear and flexion moment loads. During posterior cranial impacts compression forces and flexion moments increased from 1500 to 3200 N and 30 to 60 Nm respectively between neck angles of 30° extension and 30° flexion. This was more evident at the C5-C6 and C6-C7 joints. Anterior shear loads remained stable throughout neck angle ranges however during anterior impacts they were directed posteriorly when the neck was flexed. Conclusions. The combination of estimated joint loads in the lower cervical spine support buckling as the primary injury mechanism of anterior bilateral facet dislocations observed in misdirected rugby tackles and highlights the importance of adopting a correct tackling technique. 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

This study aims to investigate that a single dose of tranexamic acid (TXA) will reduce blood loss and transfusion rates in elderly patients, undergoing intertrochanteric (IT) or femoral neck fractures surgery. Consecutive elderly patients receiving hip fracture surgery for stable or unstable IT fracture, treated with short intramedullary nail (IMN) insertion as well as cemented hemiarthroplasty for acute femoral neck (subcapital) hip fracture, were screened for inclusion in this single-centre randomized trial. Patients were randomly allocated to a study group by sealed envelope. One TXA dose of 15 mg/kg i.v. diluted in 100 ml N/S or one placebo dose i.v. in 100 ml N/S were administered 5 mins before the skin cut. Haemoglobin (Hb) concentration was measured at admission time and prior to surgery. Post-operatively it was measured on a daily basis until day 4, giving a total of four Hb measurements (days 1 to 4). The transfusion trigger point was determined in accordance with the French guidelines for erythrocyte blood transfusion. The transfusion trigger was 10 g/dl for patients at risk, while in all other cases, it was 9 g/dl. Information regarding the transfusions number was assessed directly by the hospital blood bank database. Blood loss was calculated by the Hb dilution method. Nadler's formula was used to calculate patients' blood volume. For calculation of total blood loss (TBL) expressed to total Hb loss and total Volume loss, the number of transfusions (55 grams of Hb per transfusion), the Hb concentration on preoperatively (Hgbi) and the Hb concentration on the last measure (Hgbe) were used. (Hb balance method). The primary efficacy outcome was the number of transfusions of allogeneic RBC from surgery up to day 4. The secondary ones were the total blood loss from surgery to day 4 as it was calculated by Hb-balance method. After randomization, 35 patients with femoral neck fracture and 30 patients with IT fracture received TXA prior to surgery. Respectively, 30 patients with femoral neck fracture and 55 with IT fracture didn't receive TXA. The groups did not differ significantly in their basic demographics (age, gender, BMI, injury mechanism, ASA score, co-morbidities). Results showed that patients undergoing hemiarthroplasty after receiving TXA, were transfused with less allogeneic RBC and had less total blood loss than patients that didn't receive TXA, but without statistical significance. While patients treated with IMN in the TXA group received a significantly lower number of RBC units than the control group (1.28 ± 1.049 vs 2.075 ± 1.685), (P = 0.0396), had a significantly lower loss of Hb (98.59 ± 55.24 vs 161.6 ± 141.7), (P = 0.0195) and a lower total blood volume loss (951.3 ± 598.9 ml vs 1513 ± 1247 ml), (P = 0.023). This trial confirmed TXA administration efficacy in reducing blood loss and transfusion rate in elderly patients undergoing hip fracture surgery. A TXA single dose may be a safer option, taking into account these patients' physiological status and co-morbidities

Evidence that L5 transverse process fracture indicates pelvic instability is insufficient and controversial. Because of unstable pelvis fractures have high mortality rate, they require urgent treatment and good follow-up. The lumbar region is also affected by high-energy traumas in the pelvis region, which causes damage to the muscles and ligamentous structures that adhere to the lumbar transverse process. For this reason, L5 transverse process fracture is thought to be an indicator showing pelvic instability. However, our study shows that this is not like that. This study was carried out in order to investigate the effect of L5 transvers process fracture on pelvic instability and lack of sufficient data in the literature. Between 2017–2020, 86 Patient who were hospitalized and treated with a diagnosis of pelvic fracture were retrospectively studied in our clinic. Pelvic X-Ray and tomography was taken pre-op for all patient. Demographic features, pre-op and post-op hemoglobin counts, how many units of blood transfusion needed in total, fixation method, surgical intervention, presence of additional injury, mechanism of injury for all patient were analyzed and the patients were categorized by investigating L5 transvers process fracture in their tomography. Fractures of patients were classified according toTyle classification. The patients were divided into two main groups as who stabil and unstabil pelvic fractures and L5 transvers process fracture and without. On stabil pelvic fractures and unstabil pelvic fractures, in term of instability effects of L5 transvers process fractures and those without were investigated. Also, changes in preop and post op hemoglaobin counts were investigated in pelvis with and without L5 transvers process fractures. With these, in terms of blood transfusion need the patients were evaluated whether there was a difference between those with L5 transvers process fractures and who did not. Again, whether the blood transfusion was statistically different in stable and unstable pelvis fractures was among the parameters looked at. In statistical analysis, no correlation was found between pelvic instability and L5 transvers process fracture. (p=0,933) No statistically significant difference was found in the evalution of blood transfusion between those with and without L5 transvers process fractures. (P=0,409)When the same parameter was evaluated in terms of stability and instability of the pelvis, it was seen that stability did not significantly affect the need for blood transfusion. (P=0,989) Pre-op and post-op hemoglobin changes of the patients who with L5 transvers process fracture and without were also analized. İn the analysis performed, there was no significant difference in patients with and without L5 transvers process fractures on pre-op and post-op hemoglobin values. (p=0.771/p=0.118)However, Postoperative hemoglobin values were significanly lower in patient with L5 transvers process fracture compared to preopetative hemoglobin values. (p=0.001). L5 transvers process fracture is not a parameter to showing pelvic instability. Stabil and unstabil fractures did not change the need for blood transfusion. The literatüre still needs much more study on this topic

Acute multiligament knee injuries (MLKI) are rare, high energy traumatic injuries associated with an increased risk of lower limb complications. The objectives of this study were to investigate the adequacy of clinical assessment for neurovascular status, compartment syndrome, and deep vein thrombosis in the emergency department (ED) following acute MLKI. The authors conducted a retrospective case note review of 19 patients with MLKI presenting at the ED of a Major Trauma Centre during a 7.5-year period between June 2009 and December 2016. MLKIs were diagnosed by MRI or examination under anaesthesia and confirmed intraoperatively. Arterial assessment consisted of documented capillary refill time, dorsalis pedis and posterior tibial pulse assessment (through palpation or Doppler ultrasound), and ankle-brachial pressure index (ABPI) calculation. Neural assessment was adequate if there was documented assessment of both sensory and motor function of the superficial peroneal, deep peroneal and tibial nerves individually. Data was collected for 19 patients (17 male, 2 female). The mean age was 34 (range: 14–61). The most common injury mechanism was road traffic accident. Neurovascular assessment was suboptimal in all categories: only one patient received a satisfactory lower limb neurological assessment and no patients received complete vascular assessments. Neurovascular assessment of multiligament knee injuries was suboptimal. Reasons for this included poor documentation and lack of certain specific clinical assessments, such as ABPI calculation. We propose the introduction of an acute knee injury pro forma highlighting the components of a full lower limb neurovascular examination to rectify this problem

Cervical spine fractures are frequent in impact sports, such as rugby union. The consequences of these fractures can be devastating as they can lead to paraplegia, tetraplegia and death. Many studies have been conducted to understand the injury mechanisms but the relationship between player cervical spine posture and fracture pattern is still unclear. The aim of this study was to evaluate the influence of player cervical spine posture on fracture pattern due to an impact load. Nineteen porcine cervical spines (C2 to C6) were dissected, potted in PMMA bone cement and mounted in a custom made rig. They were impacted with a mean load of 6 kN. Eight specimens were tested in an axial position, five in flexion and six in lateral bending. All specimens were micro-CT imaged (Nikon XT225 ST Scanner, Nikon Metrology, UK) before and after the tests, and the images were used to assess the fracture patterns. The injuries were classified according to Allen-Ferguson classification system by three independent observers. The preliminary results showed that the main fracture modalities were consistent with those seen clinically. The main fractures for the axial orientation were observed in C5-C6 level with fractures on the articular process and endplates. These findings support the concept that the fracture patterns are related to the spine position and give an insight for improvements on sports rules in order to reduce the risk of injury

Summary. This study describes the use of a quasi-static, 6DOF knee loading simulator using cadaveric specimens. Muscle force profiles yield repeatable results. Intra-articular pressure and contact area are dependent on loading condition and ACL integrity. Introduction. Abnormal contact mechanics of the tibiofemoral joint is believed to influence the development and progression of joint derangements. As such, understanding the factors that regulate joint stability may provide insight into the underlying injury mechanisms. Muscle action is believed to be the most important factor since it is the only dynamic regulator of joint stability. Furthermore, abnormal muscle control has been experimentally linked to the development of OA [Herzog, 2007] and in vivo ACL strain [Fleming, 2001]. However, the individual contributions to knee joint contact mechanics remain unclear. Thus, the purpose of this study was to examine the effects of individual muscle contributions on the tibiofemoral contact mechanics using an in-vitro experimental protocol. Methodology. Contact mechanics of 6 fresh frozen cadaver knee specimens were evaluated using the UofO Oxford knee loading device. Various combinations of quadriceps-hamstring co-contraction ratios were applied to the knee while it was “suspended” between the hip and foot components of the device. Loads of six muscle groups were computed using a hill-type musculoskeletal model [Buchanan, 2004]. Simulated ground reaction forces were also applied to the knee to represent force profiles of weight acceptance during gait as it has been shown to produce peak knee joint force in the gait cycle [Shelburne et al., 2006]. For respective medial and lateral joint compartments, the mean contact area (MC-CA and LC-CA), mean contact pressure (MC-CP and LC-CP), peak pressure (MC-PP and LC-PP), and centre of force displacement (MC-COFD and LC-COFD) were determined using a 4011 piezoelectric sensor form Tekscan (Tekscan Inc. Boston, MA). Additionally, the ACL was resected and measurements were repeated. Pearson correlations (r) examined the reliability of measurements as well as the effect an ACL transection on articular loads. Results. Positive correlations were computed for the following: COFD with intact ACL (r=0.99), COFD with resected ACL (r=0.82), MC-COFD pre vs. post ACL- resection (0.91). Furthermore, preliminary results indicated a positive correlation between MC-CA and ACL integrity (r=0.97). Discussion. The repeatability of the measured dependant variables validates the use of the knee-loading device. Interestingly, contact mechanics are more variable post ACL resection for a given muscle loading condition, indicating a decrease in knee joint stability. Also, the COFD is dependent on the different ratios of muscle loads applied to the knee, which demonstrates the importance of muscle action to the modulation of contact forces

Summary Statement. The mechanism of spinal cord injury varies across the human population and this may be important for the development of effective therapies. Therefore, detailed understanding of how variables such as impact velocity and depth affect cord tissue damage is important. Introduction. Studies have shown an independent effect of impact velocity and depth on injury severity, thereby suggesting importance of the interaction between the two for spinal cord injury. This work examines both the individual and interactive effects of impact velocity and impact depth on demyelination, tissue sparing, and behavioural outcomes in the rat cervical spinal cord. It also aims to understand the contribution of the energy applied during impact, not only the impact factors. Decoupling the effects of these two impact parameters will help to describe the injury mechanism. Maximum principal strain has also been shown to be useful as a predictor for neural tissue damage in vivo and in finite element (FE) models. A better understanding of this relationship with experimental results may help to elucidate the mechanics of spinal cord injury. Methods. In this study, 54 male Sprague-Dawley rats were given a contusion spinal cord injury at impact speeds of 8 mm/s, 80 mm/s, or 800 mm/s with depths of 0.9 mm or 1.5 mm. Animals recovered for 7 days followed by behavioural assessment and examination of the spinal cord tissue for demyelination and tissue sparing at 1 mm intervals, ±3 mm rostrocaudally to the epicentre. In parallel, a previously developed finite element model of the rat spinal cord was used to examine the resulting maximum principal strains in the spinal cord for correlations with histological and mechanical impact data. Results and discussion. Impact depth was a consistent factor in predicting axonal damage, tissue sparing, and the resulting behavioural deficit. Increased impact velocity resulted in significantly higher impact energies and measureable tissue damage at the 1.5 mm impact depth, but not at the 0.9 mm impact depth and is best displayed by the percentage of axon damage at the injury epicentre. Linear correlation analysis with FEA strain showed significant (p≪0.001) correlations with axonal damage in the ventral (R2=0.86) and lateral (R2=0.74) regions of the spinal cord and with white matter (R2=0.90) and grey matter (R2=0.76) sparing. Discussion and Conclusion. The difference in injury severity to velocity at different impact depths identifies the existence of threshold interactions between the two impact factors. Beyond this point incremental increases in either velocity or depth are more likely to result in significantly increased impact energy and thus tissue damage and functional impairment. The relationship between the impact depth and velocity of injury demonstrated a more rate sensitive response to spinal cord tissue damage at the deep (1.5 mm) impact depth than at the shallow (0.9 mm) impact depth. Impact velocity also became quickly less significant than impact depth in determining tissue damage further from the epicentre. Furthermore, the results shown by this work extend the research identifying significant correlations between maximum principal strain and neurological tissue damage

The nervous system is known to be involved in inflammation and repair. We aimed to determine the effect of physical activity on the healing of a muscle injury and to examine the pattern of innervation. Using a drop-ball technique, a contusion was produced in the gastrocnemius in 20 rats. In ten the limb was immobilised in a plaster cast and the remaining ten had mobilisation on a running wheel. The muscle and the corresponding dorsal-root ganglia were studied by histological and immunohistochemical methods.

In the mobilisation group, there was a significant reduction in lymphocytes (p = 0.016), macrophages (p = 0.008) and myotubules (p = 0.008) between three and 21 days. The formation of myotubules and the density of nerve fibres was significantly higher (both p = 0.016) compared with those in the immobilisation group at three days, while the density of CGRP-positive fibres was significantly lower (p = 0.016) after 21 days.

Mobilisation after contusional injury to the muscle resulted in early and increased formation of myotubules, early nerve regeneration and progressive reduction in inflammation, suggesting that it promoted a better healing response.