Quadriceps muscle strength at 2 years following anterior cruciate ligament reconstruction is associated with tibiofemoral joint cartilage volume

PurposeQuadriceps strength deficits following anterior cruciate ligament reconstruction (ACLR) are linked to altered lower extremity biomechanics, tibiofemoral joint (TFJ) space narrowing and cartilage composition changes. It is unknown, however, if quadriceps strength is associated with cartilage volume in the early years following ACLR prior to the onset of posttraumatic osteoarthritis (OA) development. The purpose of this cross-sectional study was to examine the relationship between quadriceps muscle strength (peak and across the functional range of knee flexion) and cartilage volume at ~ 2 years following ACLR and determine the influence of concomitant meniscal pathology.MethodsThe involved limb of 51 ACLR participants (31 isolated ACLR; 20 combined meniscal pathology) aged 18–40 years were tested at 2.4 ± 0.4 years post-surgery. Isokinetic knee extension torque generated in 10° intervals between 60° and 10° knee flexion (i.e. 60°–50°, 50°–40°, 40°–30°, 30°–20°, 20°–10°) together with peak extension torque were measured. Tibial and patellar cartilage volumes were measured using magnetic resonance imaging (MRI). The relationships between peak and angle-specific knee extension torque and MRI-derived cartilage volumes were evaluated using multiple linear regression.ResultsIn ACLR participants with and without meniscal pathology, higher knee extension torques at 60°–50° and 50°–40° knee flexion were negatively associated with medial tibial cartilage volume (p < 0.05). No significant associations were identified between peak concentric or angle-specific knee extension torques and patellar cartilage volume.ConclusionHigher quadriceps strength at knee flexion angles of 60°–40° was associated with lower cartilage volume on the medial tibia ~ 2 years following ACLR with and without concomitant meniscal injury. Regaining quadriceps strength across important functional ranges of knee flexion after ACLR may reduce the likelihood of developing early TFJ cartilage degenerative changes.Level of evidenceIII.