The Clinical Utility of Strength Measures in Predicting Patient Progression Following ACLR

Area of Science:

• Orthopedics and Sports Medicine
• Rehabilitation Science
• Biomechanics

Background:

• Identifying prognostic indicators for strength progression after anterior cruciate ligament reconstruction (ACLR) is crucial for optimizing rehabilitation strategies.
• The torque-velocity relationship, a measure of muscle function, is altered post-ACLR but its prognostic significance remains unexplored.

Purpose of the Study:

• To compare the torque-velocity relationship of knee extensors (quadriceps) and flexors (hamstrings) between ACLR and uninvolved limbs.
• To determine if the torque-velocity relationship predicts subsequent achievement of satisfactory knee extensor strength.

Main Methods:

• A cohort study (Level 3 evidence) involving 189 participants post-ACLR.
• Isokinetic knee extension and flexion at 90°/s and 180°/s were performed bilaterally at approximately 5.5 and 8.3 months post-surgery.
• Torque-velocity relationship was analyzed using ANOVA, and logistic regression assessed its prognostic value for strength, IKDC, and KOOS scores.

Main Results:

• Quadriceps torque-velocity relationship significantly increased from visit 1 to visit 2 in ACLR limbs (0.22 to 0.34 Nm/kg, P < .001), but remained lower than uninvolved limbs.
• Hamstrings torque-velocity relationship showed no significant differences between limbs or over time.
• A higher visit 1 quadriceps torque-velocity relationship predicted greater likelihood of achieving satisfactory knee extension strength (≥1.23 Nm/kg; OR, 1.05; P = .04).

Conclusions:

• Quadriceps torque-velocity relationships improve post-ACLR but do not fully normalize compared to the uninvolved limb.
• The torque-velocity relationship of the quadriceps is a significant predictor of future satisfactory knee extension strength.
• This measure offers valuable insights for guiding rehabilitation progression following ACLR.