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. 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.Introduction
Case history
The number of patients undergoing total hip replacement surgery is rising and thus the number of periprosthetic fractures is set to increase. The risk factors for periprosthetic fractures include osteolysis, rheumatoid arthritis, osteoporosis and use of certain types of implants. Evidence from literature suggests that the mortality rate within one year is similar to that following treatment for hip fractures thus as surgeons it is important for us to understand the various management strategies of these fractures. Acetabular periprosthetic fractures are uncommon and classified into Type I, in which the acetabular component is radiographically stable and Type II, in which the acetabular component is unstable. It is better to prevent than to treat these fractures. Femoral periprosthetic fractures have several classifications the most commonly used is the Vancouver classification (fig 1). Type-A fractures are proximal and can involve the greater or lesser trochanter. These are often related to osteolytic wear debris and therefore revision of the bearing surface with bone grafting is recommended. AG involves the greater trochanter and AL involves the lesser, and these can usually be stabilised by cerclage wires supplemented by screws or plates if required (fig 2). Management of type B fractures is more controversial and will be discussed in depth with reference to all recent papers at the meeting and data from the Swedish Joint Registry. In summary the management is shown in fig 3. In type-C fractures, one should ensure the fixation device bypasses the femoral stem by at least 2 diaphyseal diameters. Management is as shown in fig 4.INTRODUCTION
MANAGEMENT
