Abstract
Objectives:
Patients with anterior knee pain caused by articular cartilage lesions specific to the patellofemoral joint are difficult to treat because of the joint biomechanics and shear forces experienced by this joint. There are very few studies looking at biologic restoration procedures within this joint and no study looking at only patella-based lesions. Current surgical treatments include chondroplasty, microfracture, autologous chondrocyte implantation, osteochondral autograft (OAT) and allograft (OCA). OAT and OCA procedures may help restore or replace articular cartilage while other treatment options may limit the natural ability of the knee to resist compression. The purpose of this study was to evaluate the clinical outcomes of a large series of patients undergoing a primary osteochondral allograft (OCA) or autograft (OAT) procedures to treat painful osteochondral lesions of the patella.
Methods:
This study is a retrospective clinical outcomes study of patients who underwent an OCA or OAT procedure performed by two fellowship trained surgeons at a single institution, between January 1st, 2009 and May 31st, 2019.
All patients included in this study had a minimum 1-year follow-up. OAT procedures were performed for patients with a lesion <10 mm per standard of care practice guidelines via autografts harvested from a non-weight-bearing portion of the distal femur. OCA procedures were performed for patients with lesions >10 mm using fresh donor allograft using standard press-fit techniques.
Patients were evaluated retrospectively through a chart review to collect demographic data, indications for surgery, preoperative outcome scores, intraoperative notes and recorded postoperative outcome scores. Surgical data including laterality and concomitant surgeries was also obtained via chart review. A postoperative questionnaire was utilized either in clinic, via email or telephone to collect Kujala and Knee Injury and Osteoarthritis Outcome Score (KOOS). Demographic data was collected including age, BMI, and sex.
Results:
We identified 57 patients who underwent either an OCA or OAT of which 51 had 1 year or more of follow up. The final study population consisted of 28 patients which included 22 OCA and 6 OAT procedures (16 females, 12 males) with an average age of 29.8 ± 6.6 years (16 - 43). The average lesion size was 23.0 mm (range 10 - 35mm). Average KOOS and Kujala scores of the patient cohort was 60.7 ± 22.4 (range 18.5 - 95.1) and 56.6 ± 24.2 (range 22 – 96) respectively. Age and lesion size were found to negatively correlate to KOOS and Kujala scores (p < 0.05) and the greatest predictors of clinical outcomes for both KOOS and Kujala. The effect of age was not found to be statistically significant when accounting for the size of the lesion (p = 0.073). Likewise, size was not found to be statistically significant when age was accounted for (p = 0.073). The combined effect of age and size on KOOS and Kujala was found to be statistically significant (p < 0.05).
Conclusions:
We were able to explicitly identify worsening clinical outcomes with increasing patient age and graft size. The results of this study can be used while counseling patients on the efficacy and success rate of an OAT and OCA procedure. Based on our results, younger patients with smaller lesions will exhibit better clinical outcomes when compared to older patients with larger lesions.