Increasingly, high flexion components have been touted by the industrial manufacturers of them as the implants of choice for routine total knee replacement (TKR). An acceptable flexion arc is obtainable in most patients through various intra-operative techniques; however, the importance of obtaining high flexion—which we define as greater than 120 degrees—is unclear.

In our pilot study, a review was undertaken involving 60 of the senior authors patients who attained greater than 120 degrees of flexion after receiving an implant said to be high flexion based on the presence of both a rotating platform as well as a conforming cam-and-post third condylar space.

Despite the achievement of both high flexion and impressive patient satisfaction, no functional benefits were observed—an observation that is supported in the current literature. We will explore possible reasons for this discord and note that most patients did not express the desire to regularly perform high flexion activities such as kneeling, squatting and stooping on a daily basis. Our results and evaluation of the literature lead us to question the importance placed upon the achievement of the maximum possible post-operative flexion arc as well as the importance placed in the ability to perform high flexion activities.

This, in turn, calls into question the validity of many of the currently accepted outcomes measures used to post-operatively evaluate total knee replacements.