Keith Hosking’s research while affiliated with University of Cape Town and other places

BACKGROUND: Below-knee amputation (BKA) is the safest treatment for benign aggressive and malignant bone tumours of the distal tibia, yielding good oncological and functional results. However, in selected patients where limb salvage is feasible and amputation unacceptable to the patient, limb salvage using a distal tibial replacement (DTR) can be considered. This study aims to present the oncological and functional results of the use of the latter treatment method in our unit. METHODS: A retrospective folder review was performed for all ten patients who received a modular DTR between 1 January 2005 and 31 January 2019 for a primary bone tumour, either benign aggressive or malignant. Six were female and the mean age was 31 (12-75) years. There were five patients with giant cell tumour of bone, four with osteosarcoma and one with a low-grade chondrosarcoma. The patients with osteosarcoma had neoadjuvant chemotherapy before surgery. Function was assessed by the Musculoskeletal Tumor Society (MSTS) score. RESULTS: Two patients had local recurrence treated with a BKA and one other patient died of metastases three years postoperatively. At a mean follow-up of three years, the remaining eight patients had a mean MSTS score of 83% (67-93%). There were no radiological signs of loosening, and no revision surgeries. CONCLUSION: Endoprosthetic replacement of the distal tibia for primary bone tumours can be a safe treatment option in very selected cases. Level of evidence: Level 4

BACKGROUND: Radiation-induced pathological fractures of the proximal femur are difficult to treat due to frequent non-union and hardware failure using standard fracture fixation techniques. This case series investigates endoprosthetic replacement as a treatment option METHODS: A retrospective folder review from a private hospital in Cape Town, of patients who had sustained a radiation-induced pathological fracture, was reviewed using descriptive statistics. RESULTS: Six patients met the inclusion criteria. One patient was excluded as the minimum follow-up time of six months was not met. Of the Ave patients that were analysed, all Ave sustained transverse, subtrochanteric femur fractures. Prior to definitive treatment with a proximal femoral replacement, three patients were treated with standard trauma instrumentation prior to referral to the unit, and one patient was treated with a vascularised fibular graft as their initial treatment while at the unit. One patient was treated with an endoprosthetic replacement as their first procedure at the unit. Among the three patients treated with standard trauma fixation and the one patient treated with a vascularised fibular graft, there was a 100% failure rate. One standard trauma instrumentation patient had an ablation due to free musculocutaneous flap failure and periprosthetic infection after endoprosthetic replacement. This was the only complication of endoprosthetic replacement. At a median follow-up of 15 months (min 7, max 55) the median Musculoskeletal Tumour Society score was 74% (min 63%, max 93%. CONCLUSION: This case series seeks to highlight the high failure rates seen when treating this condition with standard trauma instrumentation or biological methods. Further research is needed, but endoprosthetic replacement may be a viable alternative solution Level of evidence: Level 4. Keywords: radiation-induced fracture, pathological fracture, endoprosthetic replacement

There are few surgical options available to manage complex talar pathology that result in predictably acceptable functional and patient satisfaction scores. Recently, total talar replacement has gained popularity as a viable option. This study presents the clinical outcomes of a case series of total talar replacements in South Africa. A review of data for eight (N = 8) consecutive patients who underwent total talus replacement between July 2014 and August 2018 was performed. The American Orthopedic Foot and Ankle Society hindfoot score (AOFAS-hindfoot) was used to assess clinical function and the Short Form-36 (SF36) was used to assess patient satisfaction. Patient demographics as well as data on pathology, range of motion, gait analysis, and radiological outcomes were included. The mean age was 46 (range, 23 to 71) years. Pathologies included trauma, avascular necrosis and tumors. The mean duration of follow-up was 23 (range, 12 to 49) months. The mean AOFAS score was 79.25 (range, 69 to 88) and the mean SF-36 satisfaction score was 83.25 (range, 60 to 93). No revision surgeries have been performed to date. Seven patients demonstrated a mildly abnormal gait and one revealed a moderately abnormal gait. The patient with the longest duration of follow up showed radiological changes of tibial wear, although he remained symptom free. Our experience with the patients described in this report leads us to believe that total talar replacement is a viable surgical option in appropriately selected patients with end-stage talar pathology in the short to medium term, without compromising future salvage options.

BACKGROUND: Resection of aggressive benign or malignant tumours of the proximal fibula are difficult due to the high number of surrounding anatomical compartments and close association with many important neurovascular and functional structures. For the same reasons malignant tumours behave differently in this area. Before the 1980s results were poor. With the introduction of neoadjuvant chemotherapy and limb salvage surgery, Malawer described a technique of local en bloc resection. This study presents the oncological and functional results of a case series using this technique PATIENTS AND METHODS: A retrospective folder review of 14 patients was done. Six patients with a large active, an aggressive benign or a low-grade malignant tumour had a Malawer type I marginal resection, and eight patients with a stage IIB malignant sarcoma had a Malawer type II wide intracompartmental resection sacrificing the common peroneal nerve. The follow-up at a median of 38 months included the imaging, histology and a functional MSTS score. RESULTS: The median age of the type I resections was 42.5 years; giant cell tumour was the commonest tumour (50%); and the median functional MSTS score at follow-up was 29. The median age of the type II resections was 12 years; osteoblastic osteosarcoma was the commonest tumour (75%); and the median functional MSTS score was 26. All type II resections achieved clear margins at the initial surgery and there were no recurrences or metastases in either group. There were no wound complications and no vascular complications in spite of sacrificing the tibialis anterior artery in some type I and all type II resections, and the peroneal artery in type II resections. No patient complained of knee instability. The main functional impairment was due to loss of common peroneal function which required an AFO in some patients and a tibialis posterior tendon transfer in one patient CONCLUSIONS: Resection of benign and malignant tumours of the proximal fibula achieved good cure rates and functional results, despite the sacrifice of the common peroneal nerve Level of evidence: Level 4