The natural history of anterior cruciate ligament reconstruction using patellar tendon autograft

The purpose of this study was to review the results of ACL reconstruction using a patellar tendon graft placed ‘over the top’ plus a Macintosh lateral tenodesis, examining changes in knee laxity and functional status with increasing time. There were 74 patients operated on over an 11 year period, and divided into four groups for analysis according to postoperative time. There was a significant and progressive increase in side-to-side laxity difference with time, although functional status did not change significantly, indicating a lack of correlation between objective clinical tests and subjective findings. The highest Lysholm, Tegner and IKDC scores were at 4–5 years after operation, when 60% of patients were at their pre-injury level of sports activity. However, there was always a very significant difference between actual and desired Tegner activity levels for the group as a whole. While there was a significant correlation between degenerative changes and the time between injury and reconstruction, there was no correlation with postoperative time: this provides evidence that ACL reconstruction can protect the knee from later degeneration.