INCOMPLETE TEARS OF THE ANTERIOR CRUCIATE LIGAMENT IN ATHLETES

Abstract

To report the long term outcome of patients with a partial tear of the anterior cruciate ligament (ACL).

We reviewed 26 of 31 athletes who had a diagnosis of acute, incomplete tear of the anterior cruciate ligament (ACL) between November 1986 and December 1991. All patients had arthroscopy and examination under anaesthesia within 8 weeks of acute knee injury, and were included in the study if there were still ACL fibres remaining which resisted anterior tibial translation. We excluded patients with associated major ligamentous lesions. Patients were reviewed by a combination of questionnaire and clinical examination at a mean of 38 months after the index injury (range 18 to 66).

At review, 20 patients (77%) had developed some symptoms of knee instability. The number of patients with a positive Lachman’s test had increased from 17 to 18, and those with a positive pivot shift had increased from 9 to 13. Seven patients (27%) had undergone ACL reconstruction, 7 other patients (27%) had been unable to return to sport, and 6 patients (23%) continued to participate in sport, but at a reduced level. Only 6 patients (23%) were able to continue in sport at their pre-injury level without reconstructive surgery. Patients with a tear of the anteromedial bundle of the ACL were more likely to have signs of instability at review and to require ACL reconstructive surgery than patients with a tear mainly affecting the posterolateral bundle.

Partial lesions of the ACL, especially when involving the AM bundle, should not be regarded as benign injuries. They often result in symptomatic instability necessitating intra-articular reconstruction of the ACL, and, in the long run, in marked decrease in the level of sports participation.