Arthroscopic second look findings of an anterior cruciate ligament bone-patellar tendon-bone autograft

Nineteen patients who had undergone reconstruction of a deficient anterior cruciate ligament (ACL) by a bone-patellar tendon-bone (BPTB) autograft 12 months or more before (mean: 15.8 months) were evaluated by second-look arthroscopy. Prior to the arthroscopic evaluation the patients underwent a clinical evaluation of the results of ACL reconstruction: Muller's knee rating score and the radiographic results from lateral radiographs of the full extended knees were used. The location of the center of the tibial tunnel from the anterior end of the line of the tibial plateau was 35.2% (range: 22% to 47%) on average. The average intercondylar roof angle was 36.6 degrees (range: 28 degrees to 45 degrees). The mean percentage of roof impingement was -13.5% (range: -55% to +23%; the negative value implies no impingement, while the positive value suggests the presence of impingement). During the second-look arthroscopy the ACL graft had one or more of the following features: nearly normal appearance, incomplete synovial coverage, partially torn fibers at the femoral tunnel site, parallel fragmentation with cyclops lesion, and impingement without the damage of the ACL graft. Biopsy specimens were obtained from the nearly normal ACL graft during the second-look arthroscopy and light microscopic findings showed dense collagen fibers and spindle-shaped fibroblasts with a relatively regular arrangement (H&E, X 200). The electron microscopic findings showed that the fibroblasts had prominent indented nuclei and an abundant rough endoplasmic reticulum (X 10,200) and that the longitudinal sections of extracellular collagen fibrils demonstrated a type I collagen banding pattern (X 50,000).