Histologic presentation of achilles allograft 11 years after its use in posterior cruciate ligament reconstruction.

January 2009 E25 U se of allografts for cruciate ligament reconstruction in the knee is increasing in popularity, but graft selection remains controversial. There is a dearth of information on long-term outcomes of allografts for cruciate reconstruction. Allografts are particularly useful in posterior cruciate ligament (PCL) reconstructive surgery because this procedure is often performed with concomitant ligament reconstructions.1 In these situations, the supply of allografts may be inadequate. In addition, depending on the fixation method, autografts (eg, bone–patella tendon–bone, hamstring) may not be long enough for PCL reconstruction. Several investigators have reported favorable clinical outcomes with use of allografts in PCL reconstruction. Not well documented, however, are the long-term histologic outcomes of allografts used for ligament reconstruction and the ability of allografts to fully incorporate into host tissue. Although several investigators have documented histologic analyses of allografts used for anterior cruciate ligament (ACL) reconstructions, there has not been the same emphasis on PCL allografts.2-5 We are unaware of any previous reports on the long-term in vivo histologic presentation of tendon allografts used for PCL reconstruction. In addition, there are no such longterm histologic studies of allograft incorporation for any ligament reconstruction. In the present study, described here, we performed a histologic analysis of a freeze-dried Achilles tendon allograft harvested 11 years after it was used for PCL reconstruction. Case RepoRt A woman in her late 30s sustained an anterior knee dislocation after a motor vehicle accident. Clinical examination and magnetic resonance imaging confirmed ruptures of the PCL, the ACL, and the medial collateral ligaments. There was also a disruption of the popliteal artery. After leg revascularization, a combined ACL/PCL reconstruction was performed with 2 freezedried Achilles tendon allografts. The patient did well initially, but her knee pain worsened approximately 10 years after the initial surgery. She denied mechanical complaints and any symptoms of knee instability but noted knee pain unresponsive to antiinflammatory medication and other conservative treatment modalities. On physical examination of the knee, a minimal effusion was present, and crepitus was noted on passive range of motion. Knee ligament evaluation involved the Lachman test (3+) and the anterior drawer test (no firm endpoint). The result on the posterior drawer test was comparable to that for the contralateral limb. In addition, the knee was stable to varus/valgus loading, and external rotation at both 30° and 90° was identical to that of the left knee. Radiographs of the right knee were consistent with tricompartmental posttraumatic osteoarthritis, and the patient was scheduled for a total knee arthroplasty. Histologic Presentation of Achilles Allograft 11 Years After Its Use in Posterior Cruciate Ligament Reconstruction