To investigate why, when and which patients with an anterior cruciate ligament (ACL) rupture who initially started with rehabilitation therapy required reconstructive surgery.
In the 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 determined International Knee Documentation Committee (IKDC), numeric rating scale (NRS) pain and instability question from the Lysholm questionnaire before surgery. To determine between group differences between the non-operative treatment and delayed ACL reconstruction group, IKDC and pain scores during follow-up were determined using mixed models and adjusted for sex, age and BMI.
During two-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 (IQR 3.9-10.3). Most reconstructions occurred between three and six months after inclusion (n=17, 41.5%). Ninety percent of the patients (n=37) reported knee instability complaints as reason for surgery at the moment of planning surgery. Of these patients, 18 had an IKDC score below 60, 29 had a pain score of 3 or higher and 33 patients had knee instability complaints according to the Lysholm questionnaire. During follow-up, IKDC scores were lower and pain scores were higher in the delayed reconstruction group compared to the non-operative treatment group. At baseline, patients in the delayed reconstruction group had a significant lower age (27.4 versus 35.3 years, p=0.001) and higher pre-injury activity level compared to patients in the non-operative treatment group.
Patients who experienced instability complaints, pain during activity and had a low perception of their knee function were unsuccessful with non-operative treatment. Most patients received a delayed ACL reconstruction after 3 to 6 months of rehabilitation therapy. At baseline, patients that required reconstructive surgery had a lower age and higher pre-injury activity level compared to patients that were not reconstructed.