ARTHROSCOPIC VALIDATION OF CLASSIFICATION SYSTEMS OF MEDIAL PLICA SYNDROME

Abstract

Background: Medial plica syndrome is the most common symptomatic plica. The size and shape of the plica have an important impact on impingement on the femoral condyle and hence, symptoms. The validity of the classification systems of such injuries is essential for prospective studies. The study was designed to assess the reproducibility and reliability of Iino and Jee classification systems of medial plica syndrome. The agreement among multiple surgeons for medial plica syndrome has not been established before.

Methods: We validated both classification systems independently from the original authors at our institution. Arthroscopic videos from 30 patients were reviewed by 6 consultant surgeons, 6 registrars and 6 house officers. Intra- and inter-observer reliability and reproducibility were assessed. Each observer scored the videos on two separate occasions and classified the medial plica according to its type (A, B, C and D) for Iino classification and (1, 2, 3 and 4) for Jee classification system.

Results: The results were subjected to weighted kappa analysis. Intra-observer agreements were 0.76 for consultants, 0.64 for registrars and 0.60 for house officers for Iino classification system. They were 0.81 for consultants, 0.75 for registrars and 0.71 for house officers for Jee classification system. Total unanimity (18 observers assigned same grade for medial plica) was achieved in 23% (7 of 30) with Iino system and 40%(12 of 30) for Jee system. Inter-observer agreement was 0.63 for the first reading and 0.68 for the second reading for Iino system. They were 0.72 for the first reading and 0.80 for the second reading for Jee system. Validity analysis showed a kappa value of 0.78 (substantial agreement).

Conclusions: Jee classification system showed a better inter and intra-observer agreement compared to Iino’s system. Consultants had a better intra-observer agreement compared to their registrars. We have shown that substantial agreement can be found between individuals with no specialist training. Such reliability is crucial for multi-centre clinical research studies involving arthroscopic knee surgery. Jee’s classification system did not consider femoral condyle impingment which has an important effect on symptoms. Both systems should be used in prospective studies to evaluate the state of the medial plica.