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 ambulation 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.