Abstract
Introduction
Melorheostosis is a rare bone dysplasia characterized by its classic radiographic appearance resembling dripping candle wax. The condition was originally described by Leri and Joanny in 1922. Its etiology is not fully known and treatment in most instances has been symptomatic. There are nearly 350 reported cases on melorheostosis, joint replacement has been successfully attempted in the shoulder and knee joint. We describe a case of severe melorheostosis affecting the left hip causing secondary osteo-arthritis, which was treated with a total hip replacement (THR). To the best of our knowledge this is the first reported case of its kind in the World literature.
Case history
A 52-year-old male of Indian origin with known melorheostosis of the left leg for over 30 years, presented with symptoms suggestive of severe osteo-arthritis of the left hip. Previously he had been treated for melorheostosis of the knee joint (fig 1a & 1b) with excisions and decompression of the medial femoral condyle. His left hip became more painful over the last few years. He had a fixed flexion deformity of 20° of the hip, severe muscle wasting and the affected leg was 3 cm longer than the right leg. Radiographs (fig 2a & 2b) confirmed the presence of sclerotic new bone in the acetabulum eroding the femoral head. He had the classical dripping candle wax appearance along the medial border of the neck and shaft of the femur. He underwent a THR using a Corail-Pinnacle un-cemented prosthesis using ceramic on polyethylene bearing surfaces (fig 3a & 3b). Post operatively he made a quick recovery and there was a marked improvement in his symptoms and functional outcome scores at 6 weeks.
Discussion
Melorheostosis has an incidence of 0.9 in one million and affects men and women equally. It can affect any site in the body, however lower limbs are more commonly affected. It classically presents on only one side of the cortex of long bones. It is common in synovial joints and crosses the joint line in 35% cases. Its etiology is unknown and it is a benign condition but there are 3 reported cases in literature associated with malignancy. Chronic pain and deformity from melorheostosis can be severely debilitating for patients. Its management in most cases is conservative. Surgical intervention is advocated in chronic debilitating symptoms. Successful resection of these lesions can translate into near complete resolution of the symptoms. A Total hip replacement can be used to treat severe melorheostosis of the hip joint with complete relief of symptoms and achieving a good functional outcome in the short term.
