CC(T) Specimen Load-Bearing Capacity Related to Yield Strength and Upper-Shelf Charpy-V Energy

The load-bearing capacity of a CC(T) specimen (Center-Cracked Tension) in the ductile fracture regime is usually controlled by plastic collapse. If the material’s tearing resistance is sufficiently low, the load-bearing capacity can drop below the plastic collapse value. Here, a recently developed simple fracture mechanics-based Charpy-V impact energy criterion for plastic collapse was used to provide a best estimate assessment of the CC(T) specimen load-bearing capacity.

Sonographic bridging callus at six weeks following displaced midshaft clavicle fracture can accurately predict healing

Aims To evaluate if union of clavicle fractures can be predicted at six weeks post-injury by the presence of bridging callus on ultrasound. Methods Adult patients managed nonoperatively with a displaced mid-shaft clavicle were recruited prospectively. Ultrasound evaluation of the fracture was undertaken to determine if sonographic bridging callus was present. Clinical risk factors at six weeks were used to stratify patients at high risk of nonunion with a combination of Quick Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH) ≥ 40, fracture movement on examination, or absence of callus on radiograph. Results A total of 112 patients completed follow-up at six months with a nonunion incidence of 16.7% (n = 18/112). Sonographic bridging callus was detected in 62.5% (n = 70/112) of the cohort at six weeks post-injury. If present, union occurred in 98.6% of the fractures (n = 69/70). If absent, nonunion developed in 40.5% of cases (n = 17/42). The sensitivity to predict union with sonographic bridging callus at six weeks was 73.4% and the specificity was 94.4%. Regression analysis found that failure to detect sonographic bridging callus at six weeks was associated with older age, female sex, simple fracture pattern, smoking, and greater fracture displacement (Nagelkerke R2 = 0.48). Of the cohort, 30.4% (n = 34/112) had absent sonographic bridging callus in addition to one or more of the clinical risk factors at six weeks that predispose to nonunion. If one was present the nonunion rate was 35%, 60% with two, and 100% when combined with all three. Conclusion Ultrasound combined with clinical risk factors can accurately predict fracture healing at six weeks following a displaced midshaft clavicle fracture. Cite this article: Bone Joint Res 2021;10(2):113–121.

The Orthopaedic Trauma Society classification of open fractures

Aims To describe a new objective classification for open fractures of the lower limb and to correlate the classification with patient-centred outcomes. Methods The proposed classification was investigated within a cohort of adults with open fractures of the lower limb who were recruited as part of two large clinical trials within the UK Major Trauma Network. The classification was correlated with patient-reported Disability Rating Index (DRI) and EuroQol five-dimension questionnaire (EQ-5D) health-related quality of life in the year after injury, and with deep infection at 30 days, according to the Centers for Disease Control and Prevention definition of a deep surgical site infection. Results A total of 748 participants were included in the analysis. Of these, 288 (38.5%) had a simple open fracture and 460 (61.5%) had a complex fracture as defined by the new classification system. At 12 months, the mean DRI in the simple fracture group was 32.5 (SD 26.8) versus 43.9 (SD 26.1) in the complex fracture group (adjusted mean difference 8.19; 95% confidence interval (CI) 3.69 to 12.69). At 12 months the mean health-related quality of life (EQ-5D utility) in the simple fracture group was 0.59 (SD 0.29) versus 0.56 (SD 0.32) in the complex fracture group (adjusted mean difference -0.03; 95% CI -0.09 to 0.02). The differences in the rate of deep infection at 30 days was not statistically significant. Conclusion The Orthopaedic Trauma Society open fracture classification is based upon objective descriptors of the injury and correlates with patient-centred outcomes in a large cohort of open fractures of the lower limb. Cite this article: Bone Joint J 2020;102-B(11):1469–1474.

On Predicting Weld Specimen Fatigue Life Based on Defect Data

Prediction of fatigue life based on internal defect data is an important research topic for components built through both traditional welds and modern additive manufacturing. In this work, a systematic approach is taken to investigate application of fracture mechanics principle for this purpose. To this end, fatigue test samples are prepared from TIG-welded titanium alloy sheets and also representative weld repairs of cast plates. Metro-tomography is employed to obtain information about internal defects in the specimens before fatigue testing. After fatigue testing, fractography is used to identify the defect that led to failure and to gather information on its location and size. The information from metro-tomography and fractography are then directly compared to assess the accuracy of the tomography data. Simple fracture mechanics methods are employed to estimate the fatigue life for each specimen, considering separately tomography and fractography data. Such estimates are then compared with fatigue life from tests. Through such quantitative comparisons, the work highlights the advantages and the challenges of the fracture mechanics approach to assess the fatigue life of test specimens with internal defects. A key observation is that life estimates employing a fracture mechanics approach are reasonable when the defect leading to failure is known, but the challenge may lie in a-priori identification of the defect that would eventually lead to failure.

Treatment Strategies for Nonunion After Intramedullary Nailing for Femoral Fracture: Experiences of Fifty Nonunion Patients

Background: Femoral nonunion is mainly caused by factors such as instability of the fracture end, insufficient blood supply, or infection. However, these factors are mainly related to the different fracture types and inappropriate treatment plans. It is important to analyze the etiology of femoral nonunion and use a simple and effective treatment method to resolve it. The purpose of this study was to divide femoral nonunion into different types and give corresponding treatment strategies.Methods: We retrospectively evaluated 50 patients with femoral nonunion. Patients were divided into six groups and each group was treated with a different strategy. All patients were followed up clinically and radiologically every month until fracture healing.Results: All 50 patients were followed up with an average follow-up time of 17.44 ± 5.48 months. Based on the type of primary femoral fracture and the factors causing nonunion, we divided the femoral nonunion into six types. These included Type I: nonunion caused by instability of simple fracture (AO classification 32-A); Type II: nonunion caused by stress shielding at fracture ends of a simple fracture (AO/OTA classification 32-A); Type III: nonunion in femoral fracture with third fragment (AO/OTA classification 32-B); Type IV: nonunion in femoral fracture with segmental femoral fracture (AO/OTA classification 32-C2); Type V: nonunion in comminuted femoral fracture (AO/OTA classification 32-C3); and Type VI: nonunion caused by infection. Based on these classifications, the following methods are used to treat femoral nonunion. Type I femoral nonunion will achieve fracture healing by blocking screws, exchanging intramedullary nails, or adding plates. Type II femoral nonunion can be addressed through dynamitization or bone graft (possibly in combination with plate fixation) to achieve fracture healing. Type III femoral nonunion requires a treatment plan of bone graft or bone graft combined with plate fixation. The treatment plan for Type IV femoral nonunion is to add a plate, and autogenous bone graft if necessary. Type V femoral nonunion treatment is bone graft combined with plate fixation, or external fixation with subsequent bone segment transport or lengthening. Type VI requires placement of antibiotic bone cement or external fixation added to fix the fracture end.Conclusions: There are several factors associated with failure of femoral fracture treatments by intramedullary nailing. We need to carefully analyze the causes of fracture treatment failure. Our six classifications and corresponding treatment strategies resulted in satisfactory clinical outcomes.

Intramedullary nail fixation for the treatment of simple forearm fractures in military combatants

Background: Most of forearm fracture in military combatants are simple fracture. The traditational procedure for adult forearm fracture is open reduction and plate osteosynthesis. However, plate fixation do have the defect of nonunion, stress shielding, skin irritation. Intramedullary nail is believed to be an alternative treatment of adult forearm fractures. However, whether simple forearm fractures in military combatants could be successfully treated by intramedullary nail is not clear.Methods: Patients of military combatants with diagnosis of simple forearm fracture treated by intramedullary nail fixation were identified from 1st January 2016 to 31st November 2018 in this retrospective study. General information of the patients, time of follow-up, time of fracture union post-operation, complications, rotation activity and DASH score 12 month post-operation were recorded to figure out the clinical outcome of simple forearm fracture treated by intramedullary nail in military combatants.Outcome: Twenty male patients were identified in this retrospective study, with average age of 26.5 years old (range 18-36).Fourteen forearm fracture happened in right side and the rest six happened in left side. Single ulna fracture happened in 11 cases, single radius fracture happened in 4 cases , both forearm fracture happened in 5 cases. Classifications of the 20 patients were all OTA type A. All 20 patients got followed, with mean follow-up time of 15.8 months（range 12-18). All patients got fracture union successfully. Average time of fracture union was 2.6 months（range 2-4months）. Partially rupture of extensor pollicis longus tendon happened during operation in one patient and 3 months post-operation in another patient. One patient with both forearm fractures showed linear ossification of interosseous membranes. Average pronation activity 12 months post-operation was 86.9 degrees (range 80-90), average supination activity 12 months post-operation was 86.3 degrees (range 60-90). Average DASH score 12 months post-operation was 6.5（range 0-37).Conclusion: This respective study demonstrated that intramedullary nail achieved excellent results in the treatment of simple fracture of forearm in military combatants.Trial Registration : Not applicable