The Journal of Bone and Joint Surgery

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Commentary & Perspective

Commentary & Perspective on
"Polyethylene Wear After Total Elbow Arthroplasty"
by Brian P. Lee, MD, et al.

Commentary & Perspective by
Robin R. Richards, MD, FRCSC*,
Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada

This paper by Lee et al. addresses the issue of wear of the polyethylene articulating surface in the semiconstrained linked Coonrad-Morrey total elbow replacement design. The authors' aim was to determine the prevalence of isolated bushing exchange necessitated by wear problems, examine the factors that predispose to bushing wear, determine the diagnostic features of this condition, and report the results after revision surgery. The authors review their experience with 919 elbow arthroplasties performed over a nineteen-year period. Only twelve patients underwent exchange of the articular bushings during this long time-period, although cases of revision for loosening of the implant within the bone were excluded. An additional six patients were diagnosed as having bushing wear but did not have a revision. It must be noted that not all patients in the series had regular follow-up radiographs nor were stress views routinely performed to determine the extent of bushing wear in asymptomatic patients.

Their operative approach to exchange bushings leaves the triceps attached to the ulna and enters the pseudocapsule medially and laterally. This reviewer's operative approach is the same when performing this procedure. The authors describe removing the three bushings but do not provide any "tricks or tips" to the reader to more easily accomplish this task. In my experience, the medial and lateral bushings can usually be levered out of position by elevating the edge of the bushing with a Howarth elevator. Removal of the ulnar bushing can be more problematic if it is not worn out completely because care must be taken not to score the metal bearing surface in the ulna. The authors describe synovitis, which in my experience is universally present. They fill areas of osteolysis in the distal aspect of the humerus or the proximal aspect of the ulna with methymethacrylate, presumably to "seal" the bone cement interface. This has not been my practice, although I have noted osteolysis to be universally present when bushing wear is of sufficient severity to require a revision.

The mean interval between arthroplasty and bushing exchange was 7.9 years, and all patients had pain. Five patients had crepitus with movement of the elbow. Osteolysis was seen in the distal part of the humerus in only four patients, and bone resorption was seen in the proximal part of the ulna in three patients. The authors found synovitis in all but two patients.

Bushing exchange was technically successful in all patients, although three patients required a second bushing exchange at an average of eighty-one months after the initial bushing exchange. Two patients had a poor result secondary to ulnar nerve symptoms. The need for bushing revision was associated with a younger patient age and a history of traumatic conditions. A feature of prognostic importance was severe preoperative deformity at the time of the index total elbow arthroplasty.

The authors acknowledge that the actual prevalence of bushing wear is probably higher than their experience would indicate. They do not recommend bushing exchange in the absence of symptoms, and neither do I. They found that osteolysis was not extensive in their patients and believe that it is most commonly associated with a loose cemented stem. I too have made this observation and I have also observed osteolysis with well-fixed stems following total elbow arthroplasty, presumably due to polyethylene wear.

In my view the authors' experience represents the "tip of the iceberg." Unquestionably, semiconstrained linked total elbow arthroplasty is an excellent procedure to relieve symptoms and restore function to patients who require elbow reconstruction. With longer follow-up, I believe that the frequency of bushing exchange will increase. The authors describe the procedure as "not extensive" and state that morbidity is "minimal" in their hands. Nevertheless, a second procedure and another anesthetic are required, and, as the authors suggest, hopefully, the problem will be mitigated in the future by the development of improved design and/or materials that will improve the wear properties of the bearing surfaces. The authors also suggest the need to perform soft-tissue release and to balance elbow alignment at the time of the initial procedure.

The authors are to be commended for documenting their experience and providing us with their advice. Their experience with this procedure is extensive, and their counsel to those of us who perform a fewer number of procedures is greatly appreciated. Hopefully future improvements can be made to the prosthetic design and materials to maximize the longevity of this excellent reconstructive procedure and minimize the need for bushing exchange.

*The author did not receive grants or outside funding in support of his research or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.