Anterior cruciate ligament (ACL) injuries are often associated with other knee injuries. The prevalence of concomitant partial-thickness and full-thickness cartilage lesions at the time of anterior cruciate ligament reconstruction (ACLR) has been reported to be 20.2 and 6.4 %, respectively, in the Norwegian and Swedish knee ligament registries, and similar rates have been found in the USA. Even though concomitant cartilage lesions at the time of ACLR have shown to be a predictor of later knee osteoarthritis (OA), reports on patient-reported outcomes are conflicting. The current literature includes several studies reporting no negative effects of concomitant cartilage lesions on patient-reported outcome after ACLR. In contrast, two of the most comprehensive studies performed on this topic both conclude that full-thickness cartilage lesions present at the time of ACLR predict inferior patient-reported outcome 2–6 years after surgery.
The main purpose of this study was to broaden the knowledge on midterm to long-term prognosis after ACLR in patients with concomitant full-thickness cartilage lesions, and by that, support decision-making regarding different treatment options, and information to the patients. Consequently, the study cohort was prospectively followed for 5–9 years after ACLR to investigate whether there at follow-up were any differences in patient-reported outcome in patients with and without a concomitant full-thickness cartilage lesion.
The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used as the patient-reported outcome measure and administered to the patients prior to ACLR and at subsequent follow-ups. KOOS is a self-administered questionnaire consisting of 42 questions distributed between five separately scored subscales: Pain, Other Symptoms (Symptoms), Activities of Daily Living (ADL), Function in Sport and Recreation (Sport/Rec) and Knee-Related Quality of Life (QoL).
A search performed among the primary ACLRs reported to Norwegian National Knee Ligament Registry (NKLR) by the end of 2007 identified 30 patients that met all of the following inclusion criteria: A full-thickness cartilage lesion (ICRS grade 3 or 4), age less than 40 years, no associated ligament or meniscus injury, no previous knee surgery, less than 12 months from ACL injury to ACLR and a complete preoperative KOOS questionnaire. These 30 patients constituted the study group.
For each patient in the study group, two control patients with an isolated ACL injury and no cartilage lesion of any ICRS grade were included, generating 60 control patients. Apart from having no cartilage lesion, the control patients had to meet the same inclusion criteria as for the study group. The control patients were matched to the study patients according to age, gender, days from injury to surgery and type of graft.
At a median follow-up of 6.3 years (range 4.9–9.1), KOOS data from 29 study patients and 45 control patients were obtained and available for statistical analysis.
19 patients in the study group and 22 patients in the control group were available for radiographic examination at follow-up. The median time from surgery to radiographic examination was 8.2 years (range 6.4–9.8) for the study group and 8.4 years (range 6.7–9.8) for the control group. Standing radiographs were graded according to the original Kellgren and Lawrence criteria of knee (tibiofemoral) OA (0 normal to 4 severe).
There were no statistically significant between-group differences in KOOS scores at preoperative, nor at follow-up. Correspondingly, when comparing the change over time (from preoperative to follow-up) in KOOS scores between the two groups, no significant differences were found. The control group reported significant improvements in all KOOS subscales, while this was only true for the KOOS subscales pain, sport/rec and QoL in the study group. In both groups, the most prominent improvement from preoperative to followup was observed in the primary outcome measure KOOS QoL.
Radiographic OA was defined as Kellgren and Lawrence ≥grade 2 and was detected in the affected knee in 12 of the 19 patients available for radiographic follow-up in the study group and in 21 of the 22 patients available for radiographic follow-up in the control group (p = 0.016). The corresponding numbers for the contralateral, unaffected knees were 5 out of 19 and 9 out of 21, respectively. There were non-significant between-group differences in radiographic OA of the unaffected knee. During the follow-up period, 7 patients (24%) in the study group and 10 patients (22%) in the control group underwent a total of 23 subsequent knee surgeries.
The authors concluded that ACL reconstruction performed in patients with a concomitant full-thickness cartilage lesion restored patient-reported knee function, at 5–9-year follow-up, to the same level as ACL-reconstructed patients without such lesions. The data from the longitudinal follow-up of the current cohort suggest that patients with a concomitant full-thickness cartilage lesion can expect the patient-reported outcome to be significantly inferior at 2–5 years after surgery, but comparable to other ACL-reconstructed patients 5–9 years after surgery.
The findings should be considered in the preoperative information given to patients with such combined injuries, in terms of the expected outcome after ACL reconstruction and in the counselling and decision-making on the subject of surgical treatment of the concomitant cartilage lesion.
Ulstein S et al. (2016) No negative effect on patient‑reported outcome of concomitant cartilage lesions 5–9 years after ACL reconstruction. Knee Surg Sports Traumatol Arthrosc.