Correlations between objective measures of function and a clinical knee rating scale following total knee replacement

Few objective measurements of function, other than range of motion, have been reported for patients with total condylar knee replacement. Moreover, to our knowledge, no studies have been reported which assess the degree of relationship between clinical ratings and measurements of function in these patients. Kinesiologic tests of function and the Hospital for Special Surgery (HSS) Knee Rating Form were used to evaluate 34 patients before and 2 years after 39 total condylar knee replacements. Prosthetic alignment was also evaluated postoperatively. The kinesiologic studies showed postoperative improvement in muscle strength, weight-bearing ability, and use of assistive devices, and in velocity, knee flexion-extension, and lateral head motion during walking. A moderate but significant degree of improvement was measured by the HSS score. Correlation coefficients showed that the postoperative knee rating score was significantly related to almost all of the postoperative objective measurements of function. Correlation coefficients between the prosthetic alignment scores and measurements of function were not statistically significant. The study strengthens the validity of use of the HSS Knee Rating Form as a tool for evaluating functional performance, particularly during the postoperative period.