Outcomes before and after total knee arthroplasty compared to healthy adults

J Orthop Sports Phys Ther. 2010 Sep;40(9):559-67. doi: 10.2519/jospt.2010.3317.


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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Arthroplasty, Replacement, Knee*
  • Case-Control Studies
  • Exercise Test
  • Female
  • Humans
  • Isometric Contraction / physiology
  • Knee Joint / physiology
  • Male
  • Muscle Strength Dynamometer
  • Osteoarthritis, Knee / physiopathology
  • Osteoarthritis, Knee / surgery
  • Outcome Assessment, Health Care*
  • Postoperative Period
  • Preoperative Period
  • Prospective Studies
  • Range of Motion, Articular / physiology