Outcomes before and after total knee arthroplasty compared to healthy adults

Abstract

Study design: Prospective cohort study.

Objectives: To measure changes in muscle strength, range of motion, and function from 2 weeks before to 6 months after total knee arthroplasty (TKA) and compare outcomes with data from a control group consisting of healthy adults.

Background: Total knee arthroplasty successfully alleviates pain from knee osteoarthritis, but deficits in function can persist long term. How impairments and functional limitations change over the first 6 months after TKA, compared to data from healthy adults, has not been well reported in the literature.

Methods: Twenty-four patients who underwent a primary unilateral TKA were compared to healthy adults (n = 17). All patients participated in a standardized rehabilitation program following surgery. Isometric quadriceps torque was assessed using an electromechanical dynamometer. Range of motion was measured actively and passively. Functional performance was assessed using the stair-climbing test, timed up-and-go test, 6-minute walk test, and single-limb stance time. Patients underwent testing at 2 weeks preoperatively and at 1, 3, and 6 months postoperatively.

Results: Compared to healthy older adults, patients performed significantly worse at all times for all measures (P<.05), except for single-limb stance time at 6 months (P>.05). One month postoperatively, patients experienced significant losses from preoperative levels in all outcomes. Patients recovered to preoperative levels by 6 months postoperatively on all measures, except knee flexion range of motion, but still exhibited the same extent of limitation they did prior to surgery.

Conclusion: The persistent impairments and functional limitations 6 months after TKA with standard rehabilitation suggest that more intensive therapeutic approaches may be necessary to restore function of patients following TKA to the levels of healthy adults.

FIGURE 1

Comparison of timed up-and-go and stair-climbing test over time to healthy adults. Lower times on the TUG and SCT tests indicate improved function. Abbreviations: SCT, stair climbing test; TUG, timed up-and-go test. ^* Different from healthy adults (P<.05). Error bars indicate SD.

FIGURE 2

Comparison of 6-minute walk test distance over time to healthy adults. ^* Different from healthy adults (P<.05). Error bars indicate SD.