Present state-of-the-art in elbow arthroplasty.
Prosthetic joint replacement of the elbow is, with some delay in comparison with the shoulder, the finger joints and especially the hip and knee joint, becoming a routine operation at least in more specialised orthopedic and trauma centers. In the seventies and eighties, more than 80% of the indications were in patients affected by rheumatoid arthritis, in which both sides were typically affected, seriously jeopardising their independence in activities of daily living. In the last decade an increasing number of posttraumatic osteoarthritic cases were included in the indications. Among the numerous prosthetic devices, only a few have stood the test of time (> 10 years); a meta-analysis of the world literature shows an average follow-up of less than 5 years. Two main types of prostheses must be distinguished, linked and non-linked. The linked prostheses are, with few exceptions, so-called sloppy hinges with a clearance between both components, permitting movement in the sagittal plane and in the frontal plane and also some rotation. Using the normal anatomical stabilising structures, the stresses on the interface are reduced. This type of linked prostheses has a wider range of possible indications than the non-linked resurfacing prostheses, which require a largely preserved bone stock and intact ligaments in order to avoid instability with subluxations or even dislocations. Resurfacing prostheses can be more or less constrained according to the degree to which they mimic normal elbow anatomy. In order to reduce the stresses on the interface, the more constrained resurfacing prostheses make additional use of an intramedullary stem. The fixation of the device in the bone is achieved with bone cement in nearly all the linked and non-linked prostheses. Sloppy hinges with condylar configurations (as the GSB III elbow prosthesis) or an anterior flange (Coonrad-Morrey) further reduce the stresses on the interface and have better long-term results. Special instruments help to place the prosthesis in correspondence to the normal center of rotation and to minimise the bone resection needed and the risk of intra-operative complications (condyle fractures, shaft perforation). The results concerning pain relief and mobility are, for all properly placed prostheses, very satisfactory in the first years. A reliable account of long-term results (> 10 years of non-interrupted series of elbow prostheses) has so far been given only by a few authors. In cases with rheumatoid arthritis the survival rate at 10 years reaches 90%; the complication rate however is still definitely larger than with hip, knee and shoulder prostheses. This is particularly true for posttraumatic OA cases. Aseptic loosening, infection, instability and ulnar nerve lesions are at the fore and about twice as frequent as in RA, especially in patients below 60 years of age. In order to keep a safe retreat possibility open, we insist on the best possible preservation or reconstruction of normal anatomy (e.g. condyle reconstruction) when implanting an elbow prosthesis.