Poster 282: Effect of Pre-operative Intra-articular Injections on Return to Sport, and Clinical Outcomes Following Knee Osteochondral Allograft Transplantation

OBJECTIVES: Intra-articular injections are a common non-operative treatment for pain in knee osteoarthritis. Knee injections may also benefit patients that suffer from pain caused by osteochondral lesions which exhibit similar progressions of articular cartilage degeneration. Although some studies show clinical improvement with the use of injections, inconsistencies across study results limit our knowledge of the true effect on clinical outcomes in patients with osteochondral lesions. The purpose of this study is to evaluate the effect of pre-operative knee injections on satisfaction, pain, return to sport (RTS), and clinical outcomes following osteochondral allograft (OCA) transplantation of the knee. METHODS: This is a retrospective study of patients who underwent OCA transplantation at a single institution with at least 1 year of clinical follow-up. Patients who received knee injections including platelet rich plasma (PRP), corticosteroid (CS), and hyaluronic acid (HA) injections were identified. Patient satisfaction between patients that received injections before surgery and those who did not were assessed using a 0-100 numeric scale. Similarly, clinical outcomes were compared using a visual analog scale (VAS) for pain and the Knee Injury and Osteoarthritis Outcome Score (KOOS subscores: symptoms, pain, sports, and quality of life (QOL)). Patients were asked to report whether they returned to sport at the same level, at a lower level, or if they did not return to sport following surgery. Need for reoperation and post-operative complications including graft failure was also recorded. Patients were divided into two cohorts (those who received injections and those who did not) and outcomes were compared between the two groups using T-tests and Chi-square analyses. ANCOVA and logistic regression models were used to control for confounders. Subsequent sub-analyses were performed to identify differences between patients who received CS and HA injections specifically. RESULTS: A total of 96 patients were included in this analysis, 67 (69.7%) of which received no injection during their pre-operative course and 29 (30.2%) patients who received an injection prior to their OCA transplantation (15 patients received HA and 15 received CS injections). Patients received on average 2.6 ± 2.2 injections with the last injection on average 11.5± 14.5 months prior to the OCA transplantation. Those patients in the injection group were on average older than those in the no- injection group (40.8 ±10.1 years vs. 32.4±11.3 years, p<0.001). However, there was no difference in the number of Outerbridge high grade lesions, BMI, or gender between the two cohorts. Clinical outcomes were similar between the cohorts with patient satisfaction score of 77.6 ± 27.2 in the no injection cohort compared to 69.3 ±33.3 in the injection cohort (p=0.203) with a similar percentage of patients also reporting that they would undergo the procedure again. KOOS subscores were similar between the two cohorts after controlling for the age difference. Similar analyses were performed based on the type of injection received and also demonstrated no difference in outcomes between the two cohorts. With respect to return to sport, 59.1% of patients in the no injection group returned to sport compared to 70.4% in the injection group, p=0.308. The need for reoperation was 25.0% (24 patients) with 10 patients undergoing lysis of adhesions/manipulation under anesthesia with no difference in need for reoperation between the cohorts. Graft failure was noted in 3 patients with no difference between the cohorts. Lastly, when subanalysis was performed on patients who received CS injections and those who received HA injections, satisfaction scores for the patients who received HA injections were statistically higher even after controlling for age (79.6 ± 57.4, p=0.037). No other differences were seen when comparing patients who received HA or CS injections to those who did not receive either injection during their pre-operative period. CONCLUSIONS: There were no differences in clinical outcomes, satisfaction, return to sport, or reoperations in patients that received pre-operative knee injections compared to those that did not, irrespective of the type of injection received, prior to osteochondral allograft transplantation in the knee. The frequency of reoperations were similar between both study groups.