Abstract

Background: Osteochondral Lesions (OCL) occur due to repeated traumatic injury to bone and cartilage, triggering pathological changes of subchondral bone. Treatment effects are very variable and often poorly predictable. To date, there is no histopathological classification available.
Methods: A total of 76 cases with OCL of the ankle (64% male, 26±13 years) were included in the study and investigated by conventional microscopy and immunohistochemistry (CD56, CD68, CD31).
Result: Four histological types of OCL were identified: Type I aseptic osteonecrosis, Type II Granulation tissue with neovascularization and moderate inflammatory reaction, Type III Bone regeneration, Type IV Degenerative changes.
Conclusion: OCL structures are inhomogeneous. We assume that Type I appears as an initial phase of OCL and can turn into Types II, III or IV, whereas II and III can be seen as a continuous process, Type IV is most likely not pathologically linked to subtypes II and III. We assume that the type affecting the can influence the course of healing and treatment outcome and should be considered regarding therapy choice and initiation. We suggest a pathological investigations following arthroscopy biopsies to investigate and classify the destruction of cartilage allowing aa evaluation and improvement of treatment success.