The effect of gastrocnemius resection on knee flexion in a total knee arthroplasty model.

Introduction: Flexion contracture in knee arthritis and total knee arthroplasty (TKA) is a common and significant problem. An improvement in knee extension in patients with TKA and mild flexion contractures has been observed clinically when a gastrocnemius recession was performed for other concomitant conditions. The goal of this study was to quantify the effect of gastrocnemius recession on knee flexion in TKA cadaver model.

Materials And Methods: Range of motion (ROM) of 23 cadaveric knees was determined with a navigation system before and after performing TKA using a medial parapetallar approach and after performing a gastrocnemius recession. Varus-valgus, flexion-extension, and internal-external rotation angles of the knee joint were recorded with leg in full extension and in 90°of knee flexion. Extension and flexion gaps were measured using a gap tensioning device. Dorsiflexion of the foot was measured with a goniometer when a torque moment of 10 Nm was applied to the ankle joint.

Results: A statistically significant improvement of 5° in knee extension was observed following gastrocnemius recession (P = 0.015). Varus and valgus angles, internal, and external rotation were unaffected by gastrocnemius recession. Ankle dorsiflexion increased by 9° following gastrocnemius recession (P ≤ 0.001).

Conclusions: Performing a gastrocnemius recession improves the knee extension in TKA knees with flexion contractures. Gastrocnemius recession may be a useful technique to improve terminal extension in TKA.