Design of Elbow Replacement Changing to Meet More Patients' Needs

Joint replacement of hip, knee, and shoulder are commonplace now. Right behind those joints come ankle and elbow. This article focuses on past, present, and future total elbow arthroplasty (TEA) or replacement.

Elbow implants have been around for 30 years. They were first designed for adults with rheumatoid arthritis. But over the years, as the implant materials and technology have changed and improved, younger, more active adults with elbow arthritis following trauma, failed surgery to fix an elbow fracture, or after removal of tumors have become acceptable candidates as well.

Surgeons now have different pathology-specific implant options. In other words, they can choose the implant design that best suits the patient's problem. For example, younger patients who place high-demand on their elbows might do best with a distal humeral hemiarthroplasty (DHH) with unicompartmental radiocapitellar arthroplasty. This implant is also the one of choice for acute traumatic conditions.

Distal humeral refers to the bottom part of the upper arm (which forms the upper part of the elbow) and unicompartmental tells us only one-side of the bottom portion of the elbow is replaced (radial head). Radiocapitellar refers to the place where the radius (one of the two bones of the forearm) meets the bottom of the humerus.

The goals of elbow replacement include: pain relief, improved elbow motion, and improved function. Total elbow arthroplasty (TEA) is also an option in cases where fractures have failed to heal or healed poorly resulting in malunion and deformity.

But elbow replacement is a challenging surgery to perform. The surgeon must position the implant correctly to restore the normal axis of motion and avoid overloading or wearing out the component parts. The use of computers to assist in accurate implant placement may help improve results.

The key area in need of improvement now is reducing complications associated with TEA. There is still a considerable amount of wear on the polyethylene (plastic) portion of the implant. Other complications and problems that can develop include loosening of the implant from osteolysis (bone cells dissolve), infection, bone fracture around the implant, and weakness of the triceps muscle, which is cut in order to put the implant in place.

Less severe but more common complications include wounds that don't heal and damage during the surgery to the local nerves and blood vessels. Overall, studies show a complication rate as high as 43 per cent with a minimum of 27 per cent. Almost one-third of patients have a second (revision or reoperation) surgery.

What does the future hold for those individuals who may need a total elbow replacement? First of all, more people will qualify for this type of surgery. They will be younger, more active, and possibly have a history of earlier trauma.

Secondly, better anatomic replication of the normal elbow will be incorporated into the next generation of elbow implants. The use of joint resurfacing instead of total elbow replacement is already becoming a favored approach. Ligaments are preserved and less stress (force/load) is placed across the elbow. There may be less bone loss over time.

The hope for future implants is a more stable joint with a lower failure rate and fewer problems and complications. Studies with long-term results are not yet available (but eventually will be!) based on implants in current use to give us an idea of what is possible for these individuals.

References: Andrew Choo, MD, and Matthew L. Ramsey, MD. Total Elbow Arthroplasty: Current Options. In Journal of the American Academy of Orthopaedic Surgeons. July 2013. Vol. 21. No. 7. Pp. 427-437.