A Prospective Case Series to Evaluate the Outcomes and Acceptability of a Novel Surgical Technique of Pyrocarbon Interposition Arthroplasty of the Elbow, in Young Patients With Severe Arthritis.

Osteoarthritis (OA) of the elbow is associated with pain and loss of motion, which can have a dramatic impact on overall upper limb function due to the inability to position the hand to carry out activities of daily living. OA is characterised by osteophyte formation of the olecranon, coronoid and olecranon fossae, whilst the ulnohumeral and radiohumeral joint spaces may be relatively well preserved. The osteophytes cause terminal extension and flexion pain and impingement, whilst the limited arc of movement is often relatively pain-free. Loose bodies are also commonly present and can cause mechanical locking. Pain throughout the limited range of movement however, indicates joint destruction. This can be confirmed radiographically, which in contrast to the typical OA presentation described above, shows articular cartilage loss with narrowing or obliteration of the entire joint space, not usually seen in primary osteoarthritis. The pathologies in which loss of joint space is more commonly seen are post-septic arthritis, post-traumatic arthritis and inflammatory arthritis.

Total elbow arthroplasty (TEA) is thought to be an effective treatment for a range of pathologies including rheumatoid arthritis, late stage primary osteoarthritis, acute fracture and post-traumatic arthritis. However, it has been reported in the literature that younger patients undergoing TEA may experience earlier failure of the implant and higher complication rates. This is thought to be linked to higher functional demands placed on the implant due to greater occupational loading or participation in more demanding leisure activities. For this reason, other viable alternative to TEA are being sought by surgeons for younger patients with high functional demands.

Interposition arthroplasty has been proposed as an alternative to TEA for younger patients in the literature with various surgical techniques described. According to Thomas, the basic principle of interposition arthroplasty of the elbow is to perform a resection of the opposing bone ends and place something in between the distal humerus and the olecranon, which will then theoretically allow movement to occur without painful grinding of the joint.

Two of the major risks of TEA are aseptic loosening and periprosthetic infection. In the event of a significant joint infection, revision of the TEA procedure is often necessary and may be performed as a two-stage operation. Initially the prosthesis is removed and the infection is treated, a process that often involves the use of an antibiotic-impregnated spacer and oral antibiotics. If appropriate, once the infection is eradicated, a new prosthesis will be implanted. Cases have however been documented in the literature where the patients in receipt of spherical antibiotic cement spacers are satisfied with the movement and pain relief provided by the spacer, and subsequently decline re-implantation of a second prosthesis and. This has led the current author to question whether interposition arthroplasty using a spherical joint spacer may be a viable alternative to TEA in young patients with higher functional demands in whom there is a greater risk of premature aseptic loosening after TEA.

Pyrocarbon interposition implants have been successfully used in the small joints of the hand, wrist and foot, and more recently their use has been trialed in the shoulder with acceptable outcomes . Pyrocarbon is deemed an ideal material for the manufacture of orthopaedic implants due to its strength, resistance to wear and resistance to fatigue. It is also stated in the literature that there have been no reports of periarticular infiltration or reaction to pyrocarbon particles transmitted by the blood or lymphatic systems into organs such as the brain, kidneys or liver.