Knee Joint Accessory Motion Following Anterior Cruciate Ligament Allograft Reconstruction

Abstract & Commentary

Synopsis: The KT-2000 scores in each subject in the braced group improved while the scores for the subjects in the unbraced group became worse or stayed the same.

Source: Jenkins WL et al. Knee joint accessory motion following anterior cruciate ligament allograft reconstruction: A preliminary report. J Orthop Sports Phys Ther 1998; 28(1):32-39

After treating patients for six years, the authors believed that there was a difference in knee joint accessory motion, as measured by KT-2000 results, following bone-patellar tendon-bone allograft reconstruction of torn anterior cruciate ligaments in patients who had braces as compared to patients who did not have functional braces postoperatively. "The purpose of this retrospective study was to investigate the effect of functional bracing on knee joint accessory motion with ligament arthrometer testing during the first year postoperatively." The authors performed a retrospective chart review and found eight patients whose KT-2000 results had changed during the first postoperative year, with tibial translation increasing by 2 mm or more. Five subjects (3 males and 2 females mean age 21.2) had not worn braces and three subjects (2 males and 1 female, mean age 31.3) had received a functional brace called the "Donjoy Defiance Brace"(Smith & Nephew Donjoy, Inc., Carlsbad, CA) during the postoperative period. This knee brace supposedly limits anterior tibial translation throughout the range of motion with an emphasis on limiting it particularly at knee extension. The same physical therapist performed all of the rehabilitation and performed the KT-2000 studies. This examiner had established reliability using this technique in a previous study. The testing procedure was the traditional "manual maximum" done with the KT-2000. The reported results were the differences between the involved and the uninvolved extremity. The important finding of the study was that the KT-2000 scores in each subject in the braced group improved while the scores for the subjects in the unbraced group became worse or stayed the same.

Comment by Clayton Holmes, EdD, PT, ATC

The authors studied only eight subjects who met their criteria of increased tibial translation of treated than 2 mm in the first postoperative year. The authors do not discuss in great detail the rehabilitation and other variables in the patients' lives relative to differences in activities post-surgery. It is important to note that the authors do imply that the patients were actually treated differently in their rehabilitation post-surgery. They state that the unbraced patients were "limited in rehabilitation activities of daily living and closed kinetic chain activities using only body weight until they had three consecutive months in which their KT-2000 scores were unchanged." Later, they state that subjects in the braced group "were limited in their rehabilitation to activities of daily living and closed kinetic change activities using only body weight until they received a functional brace." The implication here is that those in the functional brace were treated more aggressively. However, it is difficult to know exactly what the subjects went through postoperatively. In addition, it is possible that instead of allowing patients to be more aggressive, the brace actually made patients more conscientious of their condition and they were actually more protective of the repair during some critical phase of healing. I would caution the reader not to apply these findings to the general population of post-ACL reconstruction patients. In my experience, KT-2000 results similar to the authors' findings do not occur when autografts are used. Also, in my experience, the effect of a post-surgical brace is negligible, and there is a paucity of information in the literature indicating the actual biomechanical effectiveness of a post-surgical bracing.