Acute anterior cruciate ligament injury and augmented repair. Experimental studies.

Eleven dogs underwent transection of the anterior cruciate ligament at the femoral origin of the stifle (knee) joint. The anterior cruciate ligaments were repaired in a conventional manner and augmented by transferring the medial one-third of the patellar tendon and inserting it into the lateral femoral condyle. The repairs were evaluated either 4 or 8 months postoperatively. All repaired and augmented anterior cruciate legaments in this series healed satisfactorily to provide clinical and functional stability to the knee joints. Instron testing of the repaired and augmented anterior cruciate ligaments showed maximum strength at 4 months of 46.2 +/- 10.9 kgf and at 8 months of 64.3 +/- 14.3 kgf as compared to the control of 122.7 +/- 11.6 kgf. Histologic evaluation showed that by 8 months the repaired and augmented anterior cruciate ligaments had healed by bony ingrowth. Thus, interstitial failure occurred during Instron testing. The transferred patellar tendon provided additonal blood supply, splinted the anterior cruciate ligament to allow healing, and increased the strength of the repaired complex.