To the Editor:

We are writing in response to the recent publications in this Journal [2, 3] regarding The Knee Society’s standardized list and definitions associated with TKA.

The importance of identifying, recording, and evaluating complications following TKA cannot be overstated. We support the importance of this list in assisting “surgeons, researchers, health plans, and government officials” to evaluate the “surgical results and patient outcomes after knee arthroplasties” [2]. However, we are concerned that this list cannot currently meet this purpose due to the absence of important complications affecting outcomes.

The most obvious example of a missing complication is pain. The reported proportion of people with unfavorable postoperative long-term pain in studies ranges from about 10% to 34% after knee arthroplasty [1]. Even in the best quality studies, approximately 20% of patients report long-term pain following knee arthroplasty [1]. Yet, this complication is not currently included in the list. Healy and colleagues’ decision to exclude conditions considered not clearly defined as complications directly related to surgery, such as poor functional outcome, limit The Knee Society’s list of complications and outcome following surgery. We would like to raise the question, should complications such as pain should be included in the list, for discussion.

The Knee Society list was developed via a literature review and survey of Knee Society members. Recent preliminary research indicates that patients report a wider variety of complications following arthroplasty, perceive the importance of complications differently than healthcare professionals, and report different complications from the Knee Society’s list [4].

It is our view that any standardized list designed to improve collection and evaluation of complications following TKA must reflect all important complications affecting outcomes — not just those associated with the surgical procedure. The Knee Society’s list currently contains important and highly relevant complications related to surgery, but does not, in our opinion, currently achieve these aims. Could this initial list be expanded to incorporate patients’ views and thus achieve a more comprehensive list of complications affecting patient outcomes? We would then be in a position to use one list to obtain a much clearer picture of complications following TKA than obtained by concentrating upon the surgical procedure alone.