The purposes of this study were to (1) evaluate postoperative quadriceps and hamstrings muscle strength loss after TKA and subsequent recovery using the nonoperative legs and healthy control legs for comparison, and (2) measure hamstrings coactivation before and after TKA during a maximal isometric quadriceps muscle contraction and compare with nonoperative and healthy control legs. 30 patients undergoing TKA were followed at 2 weeks preoperatively and 1, 3, and 6 months postoperatively and compared patient outcomes with a cross-sectional cohort of 15 healthy older adults. Bilateral, isometric strength of the quadriceps and hamstrings was assessed along with EMG measures of hamstrings coactivation during a maximal isometric quadriceps contraction. There were no differences in strength loss or recovery between the quadriceps and hamstrings muscles of the operative leg throughout the followup, although differences existed when compared with nonoperative and healthy control legs. Hamstrings muscle coactivation in the operative leg during a maximal quadriceps effort was elevated at 1 month (144.5%) compared to the nonoperative leg.
Although quadriceps dysfunction after TKA typically is recognized and addressed in postoperative therapy protocols, hamstrings dysfunction also is present and should be addressed.
Clinical Relevance Quadriceps and hamstrings muscle strengthening should be the focus of future rehabilitation programs to optimize muscle function and long-term outcomes.
Jennifer E. Stevens-Lapsley, Jaclyn E. Balter1, Wendy M. Kohrt and Donald G. Eckhoff. Quadriceps and Hamstrings Muscle Dysfunction after Total Knee Arthroplasty. Clinical Orthopaedics and Related Research, January 20 2010, online article ahead of print