SA Orthopaedic Journal

Lessons learnt from a pandemic: How to create resilience

Fixation of femoral neck fractures in patients younger than 65 years: a retrospective descriptive study at a high-volume trauma centre

BACKGROUND: The management of femoral neck fractures in the younger patient remains contentious, with high failure rates being reported in the literature. Patient age usually plays a major role during decision-making with regard to head-sparing versus head-sacrificing surgical strategies. The aim of this study was to review the outcomes of fixation of femoral neck fractures in patients younger than 65 years in an attempt to identify factors that might predict fixation failure. METHODS: A retrospective study, evaluating the outcome of fixation of femoral neck fractures in patients younger than 65 years of age was conducted. Factors affecting the outcome of treatment were explored in an attempt to identify variables that might predict fixation failure. RESULTS: The final cohort comprised 51 men (76%) and 16 women (24%) with a mean age of 43.9±12.2 years (95% CI 41.0-46.8; range 23-64) and a median follow-up of 8.7 months (IQR 6.2-17.4). Thirteen patients (19%) presented with undisplaced (Garden I and II) fractures while 54 (81%) presented with displaced (Garden III and IV) fractures. Twenty-four patients (36%) met the definition of failure. These included 15 cases (22%) of non-union, seven cases (10%) of femoral neck collapse and two cases (3%) of avascular necrosis. Sixteen patients (24%) underwent conversion to total hip arthroplasty. All cases of failure occurred in patients who presented with Garden III and IV displaced fractures. Factors associated with failure included the presence of fracture comminution (p<0.001) and the increased vertical orientation of the fracture line according to the Pauwels classification (p<0.001). Neither patient age (p=0.117), time from injury to surgery (p=0.204), mechanism of injury (p=0.136), smoking (p>0.999) nor alcohol abuse (p=0.528) was associated with failure CONCLUSION: The incidence of fixation failure following surgical management of femoral neck fractures in patients younger than 65 years of age remains high. While undisplaced fractures heal readily regardless of time from injury to surgery, mechanism of injury or fixation method, displaced fractures remain a difficult problem to solve. In our series, fixation failure was observed in one in three patients, while one in four required revision to total hip arthroplasty. Level of evidence: Level 4.

Does the intra-operatively measured leg length correction compare to the post-operative radiograph in total hip replacement surgery?

BACKGROUND: This study aims to analyse the accuracy of the Vertical Measurement System™ (VMS) in assessing the leg length correction (LLC) during total hip arthroplasty (THA) by comparing the intra-operative measurements to the radiographic measurements obtained six weeks post-operatively Patients and methods: A prospective cohort study was conducted in which patients undergoing primary THA were enrolled at two centres in Cape Town, over a period of 19 weeks. THAs were performed by four surgeons. Pre-operative leg length discrepancy (LLD) measurements were obtained in 92 patients. The VMS was used to predict intra-operative LLC, and this measurement was compared to the post-operative LLC measured on the six-week follow-up X-ray. These measurements were statistically compared using the Mann-Whitney U test. RESULTS: The difference between the intra-operative VMS calculation and the six-week radiological measurement was not significant (p>0.05), with the difference in their mean values being 0.1±3.3 mm. In the cohort, 82% of the patients (n=75) were within 5 mm of the target LLC, and 96% of patients (n=88) were within 10 mm of the target LLC. The mean absolute residual LLD at six weeks was 3.2±3.1 mm. CONCLUSION: The intra-operative LLC measurement obtained using the VMS accurately predicts the six-week post-operative radiographic LLC measurement Level of evidence: Level 4

An intra-operative device for parallel drilling and femoral landmark estimation during medial patellofemoral ligament reconstructive surgery

BACKGROUND: The aim of this study was to design and test a device to guide medial patellofemoral reconstruction surgeries. Materials and methods: A three-dimensional (3D) printed, modular and cost-effective medial patellofemoral ligament (MPFL) reconstruction guide, Pat-Rig, was designed with parallel holes running in the medio-lateral direction. This device was manufactured using a commercial additive manufacturing facility, and bench tested using a custom-built test rig. CT scans of patella bones were reconstructed, and the device was tested on four 3D-printed patellas of various sizes. RESULTS: The device was successful in guiding the surgical drill into the patella to drill parallel holes adhering to the current surgical requirements and specifications. The device was augmented with an innovative radiopaque scale which can allow the surgeon to accurately predict the landmarks to drill and measure the drill depth of the tunnels. CONCLUSION: There are no devices on the market that accurately predict the drill locations on the patella during MPFL reconstruction surgeries. The device, Pat-Rig, was found to overcome the current limitations of the MPFL surgeries and was able to provide satisfactory surgical guidance during the reconstruction. Level of evidence: Level 5

The outcome of first metatarsophalangeal joint arthrodesis using a locking compression plate

BACKGROUND: Arthrodesis of the first metatarsophalangeal joint (MTPJ) is a common and frequently performed procedure in the practice of orthopaedic foot and ankle surgery. Fusion techniques and preferred surgical implants have significantly evolved during recent years. It is however still under debate which surgical device provides the best outcome. One of the modern techniques described includes the use of a dorsal anatomical locking plate. These plates are usually used in combination with an additional compression cross screw across the arthrodesis site. The aim of this study was to assess the outcome of arthrodesis of the first MTPJ using a dorsal locking plate without making use of additional compression cross screw fixation. METHODS: We retrospectively assessed data at an orthopaedic practice specialising in foot and ankle surgery. All patients who had a first MTPJ arthrodesis with an anatomical locking plate system between 2010 and 2016 were identified. No additional compression cross screw fixation was done in any of these cases. Standard standing dorsoplantar and lateral X-rays of the foot were taken six weeks after surgery. As a primary objective, these radiographs were assessed to determine the rate of radiological union. As a secondary objective, any other complications that occurred in the post-operative period were recorded. RESULTS: We included 115 patients in the study. Fifteen of these patients underwent bilateral first MTPJ arthrodesis surgery, making the total number of feet included in the study 130. Of these, 86% (n=99) were female and 14% (n=16) were male. The mean age at the time of surgery was 54.7 years (range 37-74). An observed radiological union rate of 97% at three months after surgery was recorded. A total of four cases (3%) presented with symptomatic non-union. Two of these were successfully revised and progressed to union before the nine-month follow-up. One patient had bilateral surgery for severe rheumatoid arthritis with poor bone quality. No union was achieved even after a revision procedure with bone grafting. A Keller-type resection arthroplasty was eventually performed in this patient. Another secondary complication that was recorded is an overall infection rate of 2%. CONCLUSION: The results of this retrospective study suggest that high union rates and a low incidence of complications can be expected when fusing the first MTPJ with the use of a locking plate system without the need for an additional compression cross screw Level of evidence: Level 4

Tumour volume as a predictor of metastases in patients presenting with high-grade conventional osteosarcoma of the extremities

BACKGROUND: The aim of this study was to compare the initial tumour volume in patients with and without pulmonary and/or skeletal metastases at time of presentation. The secondary aim was to compare the value of tumour volume in the prediction of metastases at time of presentation with known predictive factors, namely serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). MATERIALS AND METHODS: A retrospective cross-sectional analysis was performed comparing the primary tumour volume in patients with and without metastases. All patients with histologically confirmed high-grade conventional osteosarcoma over a five-year period were included. RESULTS: The study comprised 61 patients. The mean age was 21 years (SD: 11.9, range 5-56) with an equal distribution of males and females (51% vs 49%). There was no correlation between tumour volume and age at presentation (p=0.31). There was no evidence of metastases in only 20% (n=12) of patients. Skeletal metastases were present in 28% (n=16) of the patients and pulmonary metastases were present in 44 cases (72%). There was no significant difference in the tumour volume at presentation between patients with and without pulmonary metastases (p=0.11). However, tumour volume did appear to predict the presence of skeletal metastases (p=0.02). A tumour volume of 1 383 cm³ had a negative predictive value (NPV) of 92% and positive predictive value (PPV) of 55% for the presence of skeletal metastases (area under curve [AUC]=0.76; sensitivity 66%; specificity 87%). A tumour volume of 480 cm³ had a 100% NPV for the presence of skeletal metastases (AUC=0.74). A tumour volume > 1 380 cm³ had an odds ratio (OR) of 13.6 (p<0.01; 95% CI 2.6-72.5) as an independent variable in relation to skeletal metastases. Multivariate analysis (with ALP and LDH) of tumour volume >1 380 cm³ yielded an OR of 8.6 (p=0.04; 95% CI 1.1-67) for presence of skeletal metastases. CONCLUSION: In this series of conventional high-grade osteosarcoma of the extremities, we found a very high rate of metastases at time of diagnosis. While there was no association with pulmonary metastases, increased tumour volume was associated with an increased risk for the presence of skeletal metastases. More studies in the developing world clinical setting are required to investigate this further; the high rate of metastases seen at time of diagnosis also requires further investigation Level of evidence: Level 4.

Osteogenesis imperfecta: an overview

Osteogenesis imperfecta (OI) is a metabolic bone disorder commonly encountered in orthopaedic practice within the context of a multidisciplinary team. Although relatively rare, it is among the most researched of the skeletal dysplasias, making it challenging for the general orthopaedic surgeon to keep abreast with current evidence. The aim of this review article is to provide a comprehensive overview of OI for the general orthopaedic surgeon. It touches on the relevant epidemiology, pathology and clinical aspects of the condition. A discussion of the background and current topical issues surrounding the classification systems, and the medical and orthopaedic management aspects follows. The main focus of this review is on the peri-operative orthopaedic care of the appendicular musculoskeletal system. We trust it will equip the general orthopaedic surgeon with concise, up-to-date and relevant information to efficiently manage affected patients and caregivers in South Africa. Level of evidence: Level 5

Fatigue failure of the femoral component of a total knee arthroplasty: a case report and review of the literature

INTRODUCTION: Reports of fatigue failure of the femoral component of a total knee arthroplasty (TKA) is scanty in the literature. As a result, there are no clearly defined risk factors to aid us in predicting fatigue failure of an implant. Furthermore, these patients may present with non-specific knee pain, which may or may not be well tolerated, depending on the stability of the implant. We report a case of fatigue failure of a poorly cemented femoral component of a TKA in a 72-year-old female, approximately seven years after the initial surgery CASE REPORT: A 72-year-old female presented to our tertiary level arthroplasty unit with new-onset knee pain approximately seven years after undergoing a TKA at our unit. She reported hearing a crack six months earlier, while standing up from a seated position. She had initially presented to her local clinic, but the pathology was missed. She received revision surgery at our institution and was doing well at early follow-up. DISCUSSION: We reviewed the literature on fatigue failure of femoral components in TKA in an attempt to define risk factors. We also summarised all cases of femoral component fatigue failure in the English literature. CONCLUSION: Although femoral component fatigue failure in TKA is rare, the majority of cases have attributed the failure to poor surgical technique. Despite this, certain implants have been failing more often than others, and proposed mechanisms for this exist. Orthopaedic surgeons need to be aware of which implant designs are prone to failure, as well as how meticulous surgical technique can reduce the chances of fatigue failure. Level of evidence: Level 5