Surgical Management of Knee Synovial Chondromatosis through Posterior Open Synovectomy: A Unique Case Report.

Introduction: Synovial chondromatosis is a rare, benign metaplastic disorder of the synovium characterized by the formation of multiple cartilaginous nodules within the joint. While the knee is the most frequently affected site, isolated posterior compartment involvement is uncommon, and massive lesions in this location are particularly rare. The anatomical complexity of the popliteal region, with its proximity to critical neurovascular structures, presents unique surgical challenges. Arthroscopic removal is often inadequate for large, posteriorly located lesions due to restricted access and visualization. Case Report: We report the case of a patient with massive synovial chondromatosis localized to the posterior compartment of the knee, presenting with progressive pain, swelling, and restricted motion. Magnetic resonance imaging (MRI) demonstrated a lobulated, multi-nodular synovial mass closely related to the popliteal neurovascular bundle. Considering the lesion size, posterior localization, and the need for complete excision, a posterior open synovectomy was performed. Through a posteromedial approach, the neurovascular structures were identified and protected, allowing en bloc removal of a large number of cartilaginous nodules along with affected synovium. Histopathology confirmed benign synovial chondromatosis. Post-operative recovery was uneventful, with restoration of the full range of motion and no recurrence at 1-year follow-up. Conclusion: This case demonstrates that in massive posterior compartment synovial chondromatosis, a posterior open approach provides superior exposure, facilitates safe neurovascular preservation, and enables complete removal of large lesions, thereby reducing recurrence risk. Early recognition of posterior localization through MRI and tailoring the surgical approach to lesion size and extent are critical for optimal outcomes.