TS10: TRABECULAR METAL SCREWS FOR AVASCULAR NECROSIS OF THE FEMORAL HEAD A SMALL CASE SERIES

Abstract

Introduction: Avascular Necrosis (AVN) of the femoral head is a complex disease that often leads to disabling hip pain and degenerative arthritis. Core decompression is currently the most common procedure used to treat the early stages of AVN but used alone may not provide adequate structural support. Trabecular metal may be a promising development by providing the support needed after a core decompression while minimizing the surgical complications of bone grafts. The important stiffness is similar to a fibular graft and the implant enables vascular healing via its porosity. This is a small series of patients who underwent this procedure which is minimally invasive. All patients had a non-traumatic aetiology for the AVN and were referred from a Rheumatology clinic closely linked to the orthopaedic clinic.

Methodology: This is a retrospective review of consecutive patients who underwent core decompression and insertion of trabecular metal (tantalum) screw for AVN of the femoral head. Preoperatively the severity of the AVN was assessed with the help of a radiologist using a modified Ficat classification (Steinberg 1986) with magnetic resonance imaging. Postoperatively the progression was assessed with x-rays.

Results: A total of nine trabecular screws were inserted into five patients with four receiving bilateral operations. Medium age was forty-five years (range 32–57) and 60% males (n=3). Steroids were thought to be the predisposing factor for AVN in all cases. Preoperative MRI studies showed Grade II disease in four hips (44.4%) Grade III in four hips (44.4%) and Grade IV disease in one hip (11.2%) Median follow up time was 14.4 months range (3–27 months). The hip with Grade IV disease went onto develop destruction of the joint and required a total hip replacement fifteen months later. This was a straightforward procedure with easy removal of the implant. The remaining hips have not required revision to date. There have been no implant failures, migration or loosening. This procedure may prove to be a clinically viable implant option for AVN and the study is ongoing. A major problem is the difficulty in seeing patients early enough with early stage disease. (stage 0, stage I and II.) There have been no implant failures migration or loosening to date.