EVALUATION OF VOLUME AND STRENGTH OF THE QUADRICEPS MUSCLE BEFORE AND AFTER ANTERIOR CRUCIATED LIGAMENT RECONSTRUCTION SURGERY

Abstract

Introduction: The anterior cruciate ligament is one of the main ligaments of the knee, often more susceptible to injuries due to its central position and its vital role in stabilizing this joint. The strength of the quadriceps plays a crucial role, with impact absorption function, helping to reduce load.

Objective: To evaluate the volume and strength of the quadriceps muscle before and after reconstruction of the anterior cruciate ligament of the knee, their correlation and which variables predict pre- and postoperative muscle strength.

Method: Prospective cohort of 37 patients evaluated preoperatively and 4 months after the operation, using magnetic resonance imaging and isokinetic dynamometry. The measurements of the limb undergoing the operation were compared to the contralateral limb as a control.

Result: The volume of the quadriceps muscle was 65.2+13.4cm3 before and 63.4+15.9 cm3 after, significantly lower in the control at both moments, with a reduction of 3.0cm3 (4.1%) in the pre and 7.8 cm3 post (12.0%). Muscle strength was 105.5+29.9N/m before and 100.9+28.6N/m after, significantly lower in the operated limb (126.4+28.2N/m and 129.6+27.6N /m, p<0.001). This reduction was similar in the 2 evaluation moments, on average of 17.5N/m (16.3%) in the pre and 22.8N/m (22.5%) in the post. The loss of strength was greater than the loss of muscle volume, with muscle volume and time of anterior cruciate ligament injury being the main determinants of muscle strength in the pre-op. The strength in the post was mainly determined by that in the pre.

Conclusion: The loss of muscle strength was 4 times greater than the loss of volume pre-operatively and 2 times greater post-operatively, indicating the beginning of recovery 4 months post-operatively.