2015 ISAKOS Biennial Congress ePoster #1513

Osteochondral Allograft Magnetic Resonance Imaging Scoring System (Ocamriss) in the Knee: Interobserver Agreement and Clinical Application

Gokhan Meric, Assoc. Prof., Istanbul TURKEY
Guilherme Gracitelli, MD, La Jolla, CA UNITED STATES
Julie McCauley, MPHc, La Jolla, CA UNITED STATES
Pamela Pulido, MD, La Jolla, CA UNITED STATES
Eric Chang, MD, San Diego, CA UNITED STATES
Christine Chung, San Diego, CA UNITED STATES
William Bugbee, MD, La Jolla, CA UNITED STATES
Department of Orthopaedic Surgery, Scripps Clinic, La Jolla, California, USA

FDA Status Cleared

Summary: Osteochondral Allograft Magnetic Resonance Imaging Scoring System (OCAMRISS) is a reproducible scoring system for analysis of cartilage defect repair following OCA transplantation for orthopaedic surgeons and radiologists

Abstract:

Introduction

Osteochondral allograft (OCA) transplantation is a suitable treatment option for primary large osteochondral defects and indicated as a salvage procedure after failed previous cartilage repair surgery. Magnetic resonance imaging (MRI) is an objective, reproducible, and non-invasive monitoring tool for postoperative assessment after cartilage surgery.
Objectives: To determine interobserver agreement of the recently developed Osteochondral Allograft MRI Scoring System (OCAMRISS) in patients undergoing OCA transplantation in the knee and correlate this score with clinical outcomes.

Methods

Our IRB-approved OCA database was used to identify 15 patients who underwent isolated OCA transplantation in the knee and received a postoperative MRI. The majority of grafts were on the femoral condyle (73%) and the mean graft area was 8.2±6.7cm2. Four examiners (two orthopaedic surgeons and two musculoskeletal radiologists) independently read each MRI and completed an OCAMRISS, which evaluates the OCA transplantation based on features of the graft (cartilage and bone) and ancillary features of the joint. Interobserver agreement among the four examiners was assessed using Cohen’s kappa coefficients for individual features and intraclass correlation coefficients (ICC) for the cartilage, bone, ancillary, and total scores. Clinical outcomes were evaluated postoperatively using International Knee Documentation Committee (IKDC) scores and the Knee injury and Osteoarthritis Outcome Score (KOOS). Correlation between the OCAMRISS and clinical outcomes was calculated using Spearman’s correlation coefficients.

Results

The mean time from OCA transplantation to MRI acquisition was 3±2.3 years. Interobserver agreement among the four examiners on individual features of the OCAMRISS was almost perfect (K=0.81 to 1.0) in 65% of comparisons, substantial (K=0.61 to 0.8) in 14%, moderate (K=0.41 to 0.6) in 18%, and fair (K=0.21 to 0.4) in 3%. Agreement among readers was very strong for the cartilage, bone, ancillary, and total scores (96% of comparisons had an ICC >0.80). IKDC function scores were correlated with the OCAMRISS cartilage score (rho=0.53, p=0.044) and total score (rho=0.67, p=0.006). The KOOS sports/recreation subscale was correlated with the OCAMRISS ancillary score (rho=0.58, p=0.049) and total score (rho=0.64, p=0.024). No correlation was observed with subchondral bone features of the OCAMRISS and any of the outcome scores.

Conclusions

MRI assessment of OCA should include cartilage and subchondral bone features. OCAMRISS is a reproducible scoring system for analysis of cartilage defect repair following OCA transplantation for orthopaedic surgeons and radiologists. Larger studies are necessary to identify and confirm correlation between OCAMRISS and clinical outcome parameters.