Why, When, and in Which Patients Nonoperative Treatment of Anterior Cruciate Ligament Injury Fails: An Exploratory Analysis of the COMPARE Trial

Abstract

Background: The optimal treatment strategy for patients with an anterior cruciate ligament (ACL) rupture is still under debate. Different determinants of the need for a reconstruction have not been thoroughly investigated before. Purpose: To investigate why, when, and which patients with an ACL rupture who initially started with rehabilitation therapy required reconstructive surgery. Study Design: Case-control study; Level of evidence, 3. Methods: In the Conservative versus Operative Methods for Patients with ACL Rupture Evaluation (COMPARE) trial, 167 patients with an ACL rupture were randomized to early ACL reconstruction or rehabilitation therapy plus optional delayed ACL reconstruction. We conducted an exploratory analysis of a subgroup of 82 patients from this trial who were randomized to rehabilitation therapy plus optional delayed ACL reconstruction. The reasons for surgery were registered for the patients who underwent a delayed ACL reconstruction. For these patients, we used the International Knee Documentation Committee (IKDC) subjective knee form, Numeric Rating Scale for pain, and instability question from the Lysholm questionnaire before surgery. To determine between-group differences between the nonoperative treatment and delayed ACL reconstruction group, IKDC and pain scores during follow-up were determined using mixed models and adjusted for sex, age, and body mass index. Results: During the 2-year follow-up of the trial, 41 of the 82 patients received a delayed ACL reconstruction after a median time of 6.4 months after inclusion (interquartile range, 3.9-10.3 months). Most reconstructions occurred between 3 and 6 months after inclusion (n = 17; 41.5%). Ninety percent of the patients (n = 37) reported knee instability concerns as a reason for surgery at the moment of planning surgery. Of these patients, 18 had an IKDC score ≤60, 29 had a pain score of ≥3, and 33 patients had knee instability concerns according to the Lysholm questionnaire before surgery. During follow-up, IKDC scores were lower and pain scores were higher in the delayed reconstruction group compared with the nonoperative treatment group. Patients in the delayed reconstruction group had a significantly younger age (27.4 vs 35.3 years; P = .001) and higher preinjury activity level compared with patients in the nonoperative treatment group. Conclusion: Patients who experienced instability concerns, had pain during activity, and had a low perception of their knee function had unsuccessful nonoperative treatment. Most patients received a delayed ACL reconstruction after 3 to 6 months of rehabilitation therapy. At baseline, patients who required reconstructive surgery had a younger age and higher preinjury activity level compared with patients who did not undergo reconstruction.