The Challenge of ACL Clearance
Time-based clearance following ACL reconstruction is clinically insufficient. Research indicates that clearing athletes for contact sport based solely on time (e.g. 6–9 months post-op) results in graft secondary rupture rates as high as 20–30%. Objective criteria incorporating isokinetic peak torque, work capacity, and limb symmetry index (LSI) significantly reduce secondary injury incidence.
Objective Isokinetic Benchmarks for ACL Clearance
LSI > 90–95%
Quadriceps and hamstring peak torque on the involved limb must achieve at least 90–95% of the uninjured contralateral limb across all velocity protocols.
Normalized Quad Torque
Absolute quadriceps peak torque at 60°/s should exceed 3.0 Nm/kg (males) or 2.5 Nm/kg (females) to ensure adequate strength for deceleration.
Dynamic Control (Hecc:Qcon)
Functional ratio of eccentric hamstring strength to concentric quadriceps strength (Hecc:Qcon) should be ≥ 1.0 at 240°/s to protect against anterior tibial translation.
Multi-Factorial Decision Battery
Isokinetic testing measures isolated joint neuromuscular capacity. Full return-to-sport decision-making combines this capacity data with Force Platform jump impulse testing (Force expression), 3D kinematics (Movement strategy), and GPS field tracking (Locomotor demand).