Study of clinical and functional outcome of total hip replacement in avascular necrosis of femoral head

Avascular necrosis (AVN) of the femoral head is one of the common causes of painful hip in a young adult. Since young age is associated with high functional demand AVN may have a devastating effect on the quality of life. The natural course of this disease is one of relentless progression with eventual collapse of the femoral head followed by secondary osteoarthritic changes in the hip. The management depends upon many factors including severity and location of necrotic lesion, patient factors and probability of collapse. Total hip replacement (THR) is needed in cases of collapse of femoral head, severe pain, osteoarthritis or destruction of hip joint. However there has been debate over whether THR is a viable option for AVN considering unique pathophysiology of AVN. Moreover the factors like functional outcome after surgery implant longevity and need for revision surgeries must be considered while doing total hip arthroplasty. In this context we conducted this prospective observational study to find out the clinical and functional outcomes of THR in patients with of AVN. Aims and Objectives: To study the clinical and functional outcome of total hip replacement in avascular necrosis of femoral head. Material and methods: Patients admitted to department of orthopedics in a tertiary care hospital in a metropolitan city with diagnosis of AVN were included in the study after taking into consideration a pre-defined inclusion and exclusion criteria for the study. Sample size of 30 was considered following statistical formula and admission registry of our hospital. Patients were recruited to the study after approval from institutional ethical committee and informed consent of patients. A detailed history was taken and thorough clinical examination was done in all patients. All patients were assessed with Harris hip score and points were allocated for each components of the score, which formed base line statistics for our study. Further patients were followed up at 6 weeks, 12 weeks and 24 weeks. Patients who could not turn up to the hospital were contacted over telephone and outcome was assessed through set of questionnaire based on Harris hip score. Result: The study consisted of 30 patients diagnosed to be having avascular necrosis of head of femur. Out of these 30 patients 23 were males and 7 patients were females with a M: F ratio of 1: 0.30. The most common age group affected was 21-40 years (43.33%) followed by 41-60 years (33.33%) and 61-80 years (23.33%). Majority of the patients with AVN had a body mass index between 25 to 29.99 (36.67%). Co-morbidities like diabetes or hypertension were seen in 11 (36.67%) patients. 9 (30%) patients were having history of either alcohol consumption or smoking. 13 patients had some predisposing factor for AVN in the form of either alcohol consumption, steroid therapy, history of trauma or pregnancy and rest of the patients were found to be having idiopathic AVN. The most common presenting complaints in the studied cases were found to be pain and difficulty in walking (90%) and most of the patients (43.33%) had symptoms for more than 1 year. Majority of the patients had right hip joint involvement (56.67%) followed by left (36.67%) and only in 2 patients (6.67%) there was bilateral involvement of hip joint. Out of the study cases 28 (93.33%) patient had cemented total hip arthroplasty while non-cemented total hip arthroplasty was seen in only 2 (6.67%) patients. There was a statistically significant difference in preoperative and postoperative total Harris hip score, pain score, range of motion, gait and daily activities like climbing stairs and distance walked. Finally in this study 28 (93.33%) patients had excellent results while 2 (6.67%) had good functional outcome after total hip replacement for avascular necrosis of femoral head. Conclusion: There was significant improvement in clinical and functional outcome after Total Hip Replacement in patients with avascular necrosis of femoral head and we recommend Total hip replacement as surgical modality of treatment for Ficat and Arlet stage 3 and 4 of avascular necrosis of femoral head.