Inter-Rater Reliability for Function and Strength Measurements in the Acute Care Hospital after Elective Hip and Knee Arthroplasty

Objective. To determine the inter-rater reliability of function and strength measurements in patients undergoing elective hip and knee arthroplasty in an acute care setting. Method. Forty-four patients underwent either total hip or knee arthroplasty. Patients were rated by 4 occupational therapists and 7 physical therapists on their performance of 5 functional tasks: lower extremity dressing, toilet transfer, supine-to-sit transfer, sit-to-stand transfer, and ambulation to 100 feet. Strength measurements of the quadriceps femoris muscle were measured quantitatively with a Microfet hand-held dynamometer. Data were analyzed to determine the interrater reliability using the Kappa statistic (K) for the functional tasks and the intra-class correlation coefficient (ICC) for the strength measurements. Results. A high level of inter-rater reliability was achieved for lower extremity dressing, toilet transfer, supine-to-sit transfer, sit-to-stand transfer, and ambu- lation to 100 feet, as evidenced by K values between 0.75 and 0.99. Reliability was also excellent for quantitative strength measurements using the dynamometer, with an ICC of 0.94. Conclusion. This study demonstrated excellent interrater reliability with measurements of function and strength post-operatively after elective hip and knee arthroplasty. The practical implication is that by using a standardized measurement tool in the acute care setting, the treatment team can more reliably assess patients' progress, which may aid clinical decision making. Hip arthroplasty; Knee arthroplasty; Rehabilitation; Outcome.