Bipolar hemiarthroplasty for stage III sickle cell-related avascular necrosis of the femoral head: a successful alternative to total hip replacement

Abstract

INTRODUCTION: The purpose of this study is to bring to the fore a simple, less expensive, biomechanically sound means of treating a devastating complication of sickle cell disease (SCD). SCD is a neglected haemoglobinopathy which is the most common cause of morbidity and mortality due to a genetic disorder. Avascular necrosis of the femoral head seen in sicklers is treated by total hip replacement which is expensive and fraught with complications of infection and revision in sickle cell patients. The simple bipolar hemiarthroplasty is easier to perform, less expensive, and relieves the patient of pain and limitation of movement. METHODS: All patients seen by one of the contributors with stage III Ficat and Arlet avascular necrosis of the femoral head (AVNFH) were assessed for pain and limitation of movement using the numeric rating scale (NRS) for pain and walking distance in metres. These were recorded. Patients were then operated on the hip via the anterolateral approach of Watson Jones. A bipolar endoprosthesis is inserted and the hip repaired. Post-operative NRS for pain and walking distances were measured and recorded. Complications such as infection, protrusion acetabula, and dislocation were also noted. RESULTS: The mean pre-operative walking distance was 172 metres with the highest being 400 and the lowest 50 metres. The mean post-operative walking distance was 614 metres indicating a more than three times improvement in the ability to walk long distances. The improvement was gradual and increased with time. The mean pre-operative NRS for pain was 6 with a range of 5 to 9. The average post-operative NRS was 3 indicating a two-fold decline in intensity of pain when sitting or walking. CONCLUSIONS: Bipolar hemiarthroplasty is a useful, successful modality of treatment for stage III osteonecrosis of the femoral head in SCD patients in low income countries.