Preoperative quadriceps strength predicts functional ability one year after total knee arthroplasty

Area of Science:

• Orthopedics
• Rehabilitation Medicine
• Biomedical Engineering

Background:

• Quadriceps weakness is a prevalent issue following total knee arthroplasty (TKA), often contributing to long-term functional deficits.
• Assessing predictive factors for postoperative function is crucial for optimizing patient outcomes and rehabilitation strategies.

Purpose of the Study:

• To determine if preoperative quadriceps strength is a superior predictor of postoperative functional ability compared to preoperative pain or knee range of motion (ROM) after TKA.
• To evaluate the predictive power of these preoperative factors on various functional outcome measures one year post-surgery.

Main Methods:

• A cohort of 40 subjects undergoing TKA were assessed two weeks preoperatively and one year postoperatively.
• Measurements included isometric quadriceps strength, SF-36 bodily pain, knee flexion ROM, Timed Up and Go (TUG) test, Stair Climbing Test (SCT), Knee Outcome Survey (KOS), and SF-36 questionnaires.
• Hierarchical regression analysis was used to assess the predictive ability of preoperative factors on postoperative outcomes.

Main Results:

• All functional measures showed significant improvement one year after TKA (p < 0.001).
• Preoperative quadriceps strength significantly predicted one-year SCT and TUG performance (p < 0.001), accounting for most of the variance.
• Neither preoperative pain nor knee ROM were significant predictors for any of the assessed functional measures (p > 0.05).

Conclusions:

• Preoperative quadriceps strength is a dominant predictor for objective functional measures like the SCT and TUG one year after TKA.
• Quadriceps strength did not significantly predict outcomes on self-report questionnaires.
• Preoperative bodily pain and knee flexion ROM demonstrated limited predictive value for all functional outcome measures.