Effects of impairment-based exercise on performance of specific self-reported functional tasks in individuals with knee osteoarthritis

Abstract

Background: Little is known regarding how impairment-based exercises may improve performance of specific functional tasks in people with knee osteoarthritis (OA).

Objective: The purpose of this study was to compare the probability that participation in an impairment-based exercise program or the same impairment-based program supplemented with agility and perturbation training will improve patient-reported function on specific functional tasks.

Design: This study was a secondary analysis of data from a randomized clinical trial.

Setting: The study was conducted in the outpatient physical therapy clinic of a large, university-based health center.

Participants: One hundred eighty-three people with knee OA (122 women, 61 men) participated.

Interventions: Participants were randomly assigned to either a group that received agility and perturbation training with standard exercise therapy or a group that received only the standard exercise.

Measurements: Specific functional items were taken from the physical function subscale of the Western Ontario and McMasters Universities Osteoarthritis Index, the Lower Extremity Function Scale, and the Activities of Daily Living Scale of the Knee Outcome Survey.

Results: The probability of self-reported improvement in a variety of specific functional tasks was low following participation in either of the exercise programs. When only participants with moderate to severe difficulty performing specific functional tasks were considered in the analysis, the probability of success improved but was still limited.

Limitations: The results are generalizable only to self-reported assessment of performance of specific functional tasks.

Conclusions: Impairment-based exercise may not be enough to make substantial improvement in performance of specific functional tasks. Task-specific exercise approaches need to be explored for people with knee OA.

Trial registration: ClinicalTrials.gov NCT00078624.

Figure 1.

CONSORT diagram of flow of participants and loss to follow-up during the study. *Other reasons included: loss of contact with the participant, participant did not complete the questionnaires, and participant did not show up for the intervention sessions.

Figure 2.

Representative examples of the contingency tables used for the Western Ontario and McMaster Universities Osteoarthritis Index physical function subscale WOMAC-PF, Lower Extremity Functional Scale (LEFS), and Activities of Daily Living Scale of the Knee Outcome Survey (ADLS) questionnaires.

Appendix.

Formulas for Calculating the Measurements of Group Change: the Relative Position (RP) According to Svensson and Starmark