THE EFFECT OF HARVESTING HAMSTRING TENDONS FOR ACL RECONSTRUCTION ON THE KNEE FLEXION STRENGTH AND PROPRIOCEPTION?

Abstract

To investigate whether the harvesting of Hamstring graft in ACL reconstruction results in compromised knee flexion strength and proprioception, and hence knee function?, a prospective study, approved by the local Ethics Committee, to assess the function and strength of the knee joint in patients who had ACL reconstruction done using a four-strand Hamstring graft. The control group was the contra lateral knees. 28 knee joints were studied with mean follow-up of 70.1 weeks (52–156). All operated knees received an extensive set regime of pre-and post-operative physiotherapy. Assessment tools were clinical examination, Laxometer arthrometry for measured anterior draw, Biodex dynamometry and Stabilometry for Hamstring and quadriceps strength and proprioception. The knee function was assessed using a questionnaire incorporating IKDC (International knee documentation committee) performa, Lysholm 2 score, Tegner’s activity scale and Oxford knee score.

Following reconstruction (mean 70.1 weeks postop), objective assessment using Biodex dynamometer showed that mean peak flexion torque around the knee joint was 69.8 N-m and 76.2 N-m in the operated and non-operated knee respectively. There was no difference in flexion torque in both groups. Mean Flexion: Extension ratio around the knee joint was 53.9% in the operated and 53.2% in non-operated sides. Mean stability index, measured using open eye stabilometry, was 3.5 (SD 2.4) in the operated side and 3.1 (SD1.8) in the non-operated side, with no significant difference demonstrable (p< 0.05).

The mean age of patients was 28.3 years (18–44). Mean IKDC score following reconstruction was 74.8 (49–100), SD18.5. Mean Tegner’s activity scale improved from 2.5(3–7) pre-operative to post-operative 5.4(3–7), p< 0.01. Mean Lysholm 2 score improved from 53.4(41–76) pre-operatively to 85(64–100) post-operatively, p< 0.01. Subjective function of the knee on a scale of 0–10 improved from pre-operative 3.1 to post-operative 7.7 (p< 0.01). Arthrometry at 25-degree flexion and 130 N force using Laxometer showed mean anterior laxity 5.3mm on the operated side and 3.1 on the healthy side (side to side difference 2.2mm).

Conclusion: The function of the knee improved significantly following ACL reconstruction both objectively and subjectively. The harvesting of Hamstring as a graft neither compromises the flexion torque nor the proprioception around the knee joint.