Reliability and Accuracy of the Outerbridge Classification in Staging of Cartilage Defects.

OBJECTIVE: The decision on whether or not and how to treat a local cartilage defect is still made intraoperatively based on the visual presentation of the cartilage and findings from indentations with an arthroscopic probe. The treatment decision is then usually based on grading according to established classifications systems, which, therefore, need to have high reliability and accuracy. The aim of the present study was to evaluate the reliability and accuracy of the Outerbridge classification in staging cartilage defects. METHODS: We performed an observer arthroscopic study using the Outerbridge classification on seven fresh-frozen human cadaveric knees, which collectively exhibited nine cartilage defects. To evaluate accuracy, defect severity was verified through histological examination. Interrater and intrarater reliabilites were calculated using Cohen's kappa and the intra-class correlation coefficient (ICC 3.1). RESULTS: The interrater and intrarater reliability for the Outerbridge classification ranged from poor to substantial, with 0.24 ≤ κ ≤ 0.70 and κ = 0.55 to κ = 0.66, respectively. The accuracy evaluated by comparison with the histological examination was 63% overall. The erroneous evaluations were, however, still often at the discrimination of grade 2 and 3. We did not find any relationship between higher experience and accuracy or intraobserver reliability. Taken together, these results encourage surgeons to further use diagnostic arthroscopy for evaluating cartilage lesions. Nevertheless, especially in grade 2 and 3, deviations from the histology were observed. This is, however, the point where a decision is made on whether to surgically address the defect or not. CONCLUSION: Diagnostic arthroscopy is the standard for cartilage lesion assessment, yet interobserver reliability is fair to substantial. Caution is warranted in interpreting varied observer results. The accuracy of the "simpler" Outerbridge classification is insufficient compared to histological examinations, highlighting the need for improved techniques in guideline-based intraoperative decision-making.

[Surgical treatment of a symptomatic intra-articular osteoid osteoma (IAOO)]. / Operative Therapie eines symptomatischen intraartikulären Osteoidosteoms (IAOO) in der Trochlea femoris.

The intra-articular osteoid osteoma (10% of cases) is a rare clinical finding. Based on atypical clinical signs and various radiological results the period to obtain a diagnosis and initiate the appropriate treatment is often very long. This case reports on a 32-year old female patient with knee pain on flexion and stress, which rarely occurred at night. Radiofrequency ablation (RFA) was contraindicated for IAOO in the trochlea femoris due to the direct subchondral location. Therefore, surgical rehabilitation by means of a cartilage-bone transplantation was carried out.