Quadriceps Strength Predicts Self-reported Function Post-ACL Reconstruction.

Area of Science:

• Orthopedics
• Sports Medicine
• Rehabilitation Science

Background:

• Quadriceps strength is a critical indicator of functional outcomes following anterior cruciate ligament reconstruction (ACLR).
• The comparative predictive value of quadriceps strength normalized to body mass (QBM) versus quadriceps strength limb symmetry index (QLSI) for self-reported function in ACLR patients remains unclear.

Purpose of the Study:

• To investigate whether QBM or QLSI is a superior predictor of high self-reported function in individuals who have undergone ACLR.
• To determine if QBM and QLSI can identify ACLR patients achieving ≥90% on the International Knee Documentation Committee (IKDC) index.

Main Methods:

• A cross-sectional study involving 96 individuals with a history of primary unilateral ACLR.
• Bilateral isometric quadriceps strength was measured to compute QBM and QLSI.
• Receiver operating characteristic (ROC) curve analyses were employed to assess the predictive accuracy of QBM and QLSI for high IKDC scores.

Main Results:

• QBM demonstrated high predictive accuracy (AUC = 0.76) for identifying individuals with high function (IKDC ≥90%).
• A QBM cutoff of 3.10 N·m·kg significantly increased the odds of reporting high function (8.15 times).
• QLSI showed moderate accuracy (AUC = 0.62), with a cutoff of 96.5% increasing the odds of high function by 2.78 times.

Conclusions:

• Quadriceps strength normalized to body mass (QBM) is a more robust predictor of high self-reported function post-ACLR compared to QLSI.
• Incorporating QBM measurements into rehabilitation guidelines may aid in identifying ACLR patients likely to achieve high functional outcomes.