Prospects for non-surgical intervention in artificial joint loosening

Abstract

Aseptic failure of total hip and other arthroplasties due to osteolysis is of significant concern to the orthopaedic surgeon. We now think we know how this osteolysis occurs. Wear particles produced from prosthetic joints interact with macrophages and stimulate the production of mediators which induce bone loss. There is now the prospect of inhibiting this process by treatment with drugs. Recent studies carried out in vitro and in animal models have identified three potential sites at which drugs would prevent wear particle induced bone loss. 1. Inhibition of the initial interaction of wear particles and macrophages by drugs such as chloroquine and bafilomycin. 2. Inhibition of the release of bone resorbing mediators from macrophages by antiinflammatory drugs such as piroxicam, naproxen and pentoxyphyline. 3. Inhibition of the effects of bone resorbing mediators by drugs such as pamidronate. The use of these types of treatments will ultimately depend on comparing the possible adverse effects with the benefits which the treatments might attain. While drug treatment can now be considered for patients with radiological evidence of early bone loss surrounding the prosthesis, prophylactic treatment in patients with stable implants may eventually emerge as a possibility.