Activity level and subjective knee function 15 years after anterior cruciate ligament injury: a prospective, longitudinal study of nonreconstructed patients

Abstract

Background: The activity level and subjective knee function after an anterior cruciate ligament (ACL) injury treated without reconstruction have not been well elucidated.

Hypothesis: Patients with ACL injury can achieve good knee function and satisfactory long-term activity level when treated by early activity modification combined with rehabilitation.

Study design: Cohort study (prognosis); Level of evidence, 2.

Materials and methods: One hundred patients with an acute total ACL injury were observed for 15 years. All patients initially underwent arthroscopic surgery and a rehabilitation program. They were advised to modify their activity level, especially by avoiding contact sports. Patients with recurrent giving-way episodes and/or secondary meniscal injuries that required fixation (n = 6) were subsequently excluded and underwent reconstruction (n = 22). Sixty-seven patients with unilateral nonreconstructed ACL injury remained at the 15-year follow-up. The Lysholm knee score, Tegner activity level, and a visual analog score for global knee function were recorded at regular intervals. At the final follow-up, patients were further evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) subjective knee evaluation form.

Results: Forty patients resumed their preinjury activity level or higher within 3 years. The median activity level 15 years after injury had decreased from 7 to 4 according to Tegner activity scale (P < .001). The mean Lysholm knee score was 96 and 95, 1 and 3 years after injury, respectively, but declined to 86 after 15 years (P < .001). Forty-nine patients had good/excellent results, and 14 had fair (n = 6) or poor function (n = 8) at 15 years. Patients injured in contact sports scored lower in the quality of life sub-scale of KOOS than those injured in noncontact sports (P < .05). Thirteen of the 67 patients (19%) were reoperated with an arthroscopic procedure because of knee symptoms.

Conclusion: Early activity modification and neuromuscular rehabilitation resulted in a good knee function and an acceptable activity level in the majority of the nonreconstructed patients. The decline in activity level of patients engaged in contact sports at the time of injury affected their subjective quality of life more than patients involved in noncontact sports.