Graft incorporation within the tibial bone tunnel after anterior cruciate ligament reconstruction with bone-patellar tendon-bone autograft

We described histologic changes in patellar tendon autografts that occur ov er time within the tibial tunnel in specimens harvested from patients under going revision anterior cruciate ligament reconstruction. Ten patients, ave raging 21.2 years of age, were divided into two groups based on the time pe riod between their original and revision surgery: early revision (less than 1 year, four patients) and late revision (more than 1 year, six patients). Among the early revision group, the tendon within the tunnel showed increa sed cellularity and random collagen bundles. A specimen from the shortest e arly revision case revealed a normal original bone-tendon junction, whereas others showed an obscured structure, Between the tendon and the tunnel wal l, granulation tissue was seen and the bone-tendon junction was still immat ure. In the late revision group, the tendon appeared similar to normal liga ment. The original bone-tendon junction was not seen, and the tendon contin ued completely to the tunnel wall with Sharpey-like fibers. Observations in the early revision group suggest that tendon remodeling and bone-tendon in tegration continue for at least several months after transplantation. The o riginal bone-tendon junction appears to have shifted to the proximal patell ar tendon-tunnel wall junction with time. These findings are in agreement w ith prior animal studies.