Introduction Reconstruction of the torn anterior cruciate ligament (ACL) allows the patient to resume sporting activity and improves objective knee function scores. We have undertaken a prospective study to describe the results of ACL reconstruction over two years, comparing patella tendon versus semitendinosus tendon autograft reconstruction.

Methods Sixty-eight patients with documented ACL injury were followed-up prospectively for an average of 27 months post surgery. The patients underwent ACL reconstruction either using the quadruple strand semitendinosus/gracilis graft or the central one third ‘bone-patella-tendon’ bone autograft. The study cohort included a total of 34 patients reconstructed with patella tendon autograft and 34 patients reconstructed with semitendinosus autografts. The choice of procedure was based on surgeon preference. All patients were assessed pre-operatively, at three months, six months and 24 months post-operatively using the IKDC knee score, Biodex dynamometer and KT-1000 instrumented test for ligament laxity.

Results Thirty-two patients were evaluated at 24 months. Our study population consists of 32 patients (17 patients with patella tendon reconstruction and 15 patients with semitendinosus reconstruction). All the patients had laxity to anterior translation by KT-1000 arthrometry pre-operatively. An IKDC score of good or excellent was obtained in one percent of patients. Both groups had significant post-operative improvements in knee laxity to anterior translation and IKDC score at p< 0.01. At two years 13 of the 15 semitendinosus graft patients (86.7%) demonstrated normal laxity, compared with 13 of 17 of the patella tendon graft patients (76.5 %). The IKDC score revealed 60% scoring good to excellent in the semitendinosus group versus 46% in the patella tendon group. Of the patients who had meniscectomy, 53% scored poorly by IKDC evaluation compared with 36% in the group which did not undergo meniscectomy. At three months post-reconstruction, the patella tendon group had a larger percentage of patients with knee laxity (86.6%), compared to 53.3% (semitendinosus group). This trend was reversed at two years (76.4% compared to 86.7% respectively). Based on the Biodex strength and endurance testing at two years compared with that done pre-operatively there was weakness of the hamstring muscles post-reconstruction.

Conclusions Reconstruction of the ACL is associated with significantly better outcome at two years. Semitendinosus graft reconstruction is not associated with significantly improved knee score and laxity, but has less donor-site morbidity.