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- Title
Voluntary Activation and Decreased Force Production of the Quadriceps Femoris Muscle After Total Knee Arthroplasty.
- Authors
Mizner, Ryan L.; Stevens, Jennifer E.; Snyder-Mackler, Lynn
- Abstract
Background and Purpose. Quadriceps femoris muscle weakness as manifested by a decrease in force-generating capability is a persistent problem after total knee arthroplasty (TKA). The authors hypothesized that (1) patients with a TKA would have decreased quadriceps femoris muscle performance (weakness) and impaired volitional activation when compared with a group of older adults without knee pathology, (2) pain and age would account for a large portion of the variability in volitional activation after surgery, and (3) volitional activation in the TKA group would account for a large portion of the variability in force production. Subjects. Comparison subjects were 52 volunteers (mean age=72.2 years, SD=5.34, range=64-85). The TKA group comprised 52 patients (mean age=64.9 years, SD=7.72, range=49-78) with a diagnosis of osteoarthritis who had undergone a tricompartmental, cemented TKA. Methods. Knee extension force was measured using a burst superimposition technique, where a supramaximal burst of electrical stimulation was superimposed on a maximal voluntary isometric contraction (MVIC). The amount of failure of volitional activation is determined by the amount of electrical augmentation of force beyond a person's MVIC at the instant of the application of the electrical burst. Results. The average normalized knee extension force of the TKA group was 64% lower than that of the comparison group. The average volitional activation deficit in the TKA group (26%) was 4 times as great as the comparison group's deficit (6%). Age did not correlate with quadriceps femoris muscle activation, and knee pain explained only a small portion of the variance in knee extension force (r² = .17). Volitional activation was highly correlated with knee extension force production (r² = .65). Discussion and Conclusion. Considerable quadriceps femoris muscle inhibition after surgery has several implications for recovery. Rehabilitation programs that focus on volitional...
- Publication
Physical Therapy, 2003, Vol 83, Issue 4, p359
- ISSN
0031-9023
- Publication type
Academic Journal
- DOI
10.1093/ptj/83.4.359