Avascular necrosis of femoral head - Demographic profile, natural history of asymptomatic hips and native hip survivorship in an indian subcontinent cohort.

Background: Avascular Necrosis of the femoral head is still considered an unsolved orthopedic problem despite significant research and advances in treatment. Purposes: 1.Describe the demographic pattern2.Assess postoperative survival of the native hip3.Observe the natural history in asymptomatic hips. Patients and methods: A South Indian quaternary care hospital based retrospective study. Patients diagnosed with non-traumatic avascular necrosis of the femoral head who underwent hip-preserving procedures between 2004 and 2017 were studied. The clinical and radiological outcomes were assessed. Statistical analysis for hip survival was done using Kaplan-Meier survival analysis. Results: The study was conducted on 306 hips of 190 patients. The most common etiology was steroid intake. The average follow-up period was 8 years. 216(76 %) hips survived clinically and 125(44 %) hips survived radiologically. The mean duration of clinical survival was 8 years and radiological survival was 7.5 years. The overall regression was highest in the fibula grafting. In asymptomatic hips clinical failure was observed in 36(53 %) hips and radiological failure in 52(77 %) hips with a mean follow-up of 5.9 years. Conclusion: The earlier stage of presentation and a hip-preserving surgery exhibited a 70 % chance of survival of the native hip. Core decompression decreased the rate of progression in the early stages. Disease regression rates were significant in fibula grafting for stages 2a and 2b. Non-operative treatment is not advisable given rapid disease progression.