Tunnel widening in anterior cruciate ligament reconstruction: a prospective evaluation of hamstring and patella tendon grafts

Abstract

We report a prospective series evaluating the incidence and degree of tunnel widening in a well‐matched series of patients receiving a hamstring or patella tendon graft for anterior cruciate ligament (ACL) deficiency. We correlated tunnel widening with clinical factors, knee scores, KT‐1000 and isokinetic muscle strength to determine the clinical significance of this finding. Seventy‐three patients at least 12 months post‐ACL reconstruction were evaluated. Thirty‐eight patients had received a doubled semitendinous and gracilis graft and 35 a bone‐patella tendon‐bone graft. All patients underwent a similar endoscopic procedure and accelerated postoperative rehabilitation. Tunnel widening was determined using standardized anteroposterior (AP) and lateral X‐rays adjusted for magnification. A limited series of MRIs was performed to validate these measurements. There was a significant difference in the degree of tunnel widening between the two groups. The mean increase in femoral tunnel area in the hamstring group was 100.4% compared with a decrease of 25% in the patella tendon group (P = < 0.0001). In the tibial tunnel the mean increase in the hamstring group was 73.9% compared with a decrease of 2.1% in the patella tendon group (P = < 0.0001). The MRIs validated the plain film measurements. Tunnel widening did not correlate with the clinical findings, knee scores, KT‐1000 or isokinetic muscle strength. Tunnel widening is marked in the hamstring group. Tunnel widening does not correlate with instability or a poor clinical outcome in the short term. The long‐term implications of this finding are still to be determined.