[Long-term results of endoprosthetic joint replacement and synovectomy]

The operations most frequently performed for chronic polyarthritis are synovectomy and artificial joint replacement. The radioisotope synovectomy has in general reduced the need for operative synovectomy. Multicenter studies of the late results of operative synovectomy (over 10 years after the operation) show a lasting improvement in pain, although radiographically the destructive changes that are seen 10 years after the operation are similar to the non-operated side. The synovectomy can therefore buy important time since re-operation, e.g. arthroplasty, is performed mainly on clinical grounds and not on the roentgenographic appearance. Operative synovectomy (Larsen 0-2) is indicated when the radioisotope synovectomy fails. It should be performed as soon as possible. Primary operative synovectomy is mainly advised when mechanical factors are predominant (tenosynovitis, large masses of fibrin in a joint etc.) and where a denervation effect is produced at the same time (e.g. in the wrist). The remainder of this report concerns the multiplicity of problems with the various wrist- and finger joint-arthroplasties. Cemented prostheses and those with a fixed axis have been shown in the world literature to have a high need for re-operation because of loosening and secondary deformities of the fingers. The silastic spacer is more adaptable but is not without problems. This is particularly seen with constitutional or cortisone-induced ligamentous laxity where bone resorption due to the piston effect and abrasion becomes evident together with sinking and often breakage of the prosthesis. The attempts made to prevent this are reported. The improvement in function from the MP-arthroplasty is very dependent upon the condition of the PIP-joints and the thumb. The significance of this with respect to the operative indication is discussed. Although the PIP-arthroplasty can initially have a good range of motion, a reduction after a number of years can be seen because of periprosthetic fibrosis. In general, when the operative indication is correctly made and with good postoperative management, arthroplasty can give good long-term results. The carpometacarpal joint of the thumb is relatively seldom involved in polyarthritis and the main indication for arthroplasty is osteoarthritis. The extent of trapezium resection and the various types of prostheses are discussed. The authors warn against treating a single joint in isolation without considering the other joints which work together with it in a functional chain.