Reliability of the novel MRI-based OCD lesion healing assessment tool for adolescent OCD of the knee

BACKGROUND: One of the most debatable issues in osteochondritis dissecans (OCD) research is bone and cartilage healing assessment during OCD postoperative management. The x-ray scale developed by Wall and colleagues is a commonly used evaluation tool for OCD lesion assessment. This tool has excellent reliability but is associated with radiologic exposure. Also, it provides complete information about bone structure only, even though the articular cartilage is also involved in the pathological process. Lack of cartilage assessment combined with radiation exposure facilitated the development of the novel MRI-based OCD healing assessment tool. It could draw attention to bone and cartilage during healing assessment to improve decision-making in the postoperative period after OCD treatment. AIM: This study assesses the reliability of a developed novel MRI-based OCD healing assessment tool. MATERIALS AND METHODS: Ten patients with OCD of the femoral condyle were involved in the current study. A reliability test for the novel MRI-based assessment tool was performed with the expert group comprising six participants to assess 34 MRI studies of 10 patients. From all studies, one study was obligatory for each patient before the operative treatment, and a postoperative MRI study series was performed during the first postoperative year. Each MRI study was examined by each expert twice with a 4-week time lag. The novel MRI-based assessment tool consists of five criteria, of which the common criterion was general healing, incorporating all previously described ones. Each criterion was tested, and a two-way mixed-effects intraclass correlation coefficient (ICC) was used to assess intraobserver and interobserver reliability. RESULTS: The main parameter general healing calculations were made first. Two patients achieved full OCD lesion healing with 100 scale points and two patients with 97.5 and 98.5 points, respectively. Other patients reached the cut-off value of 75 points and were defined as healed with minimally detectable changes on MRI. Second, a two-way mixed-effects ICC calculation was performed. The bone marrow extension parameter reached the value of 0.972, the extent of the union 0.984, bone structure 0.977, and articular cartilage intensity and structure 0.977. The general healing parameter reached the value of 0.993. These values corresponded to the excellent marks according to the guidelines for ICC assessment. The novel MRI-based assessment tool showed excelle