Khodamorad Jamshidi - Bone and Joint Reconstruction Research Center, Department of Orthopedics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
Seyyed Mohammad Ata Sharifi Dalooei - Bone and Joint Reconstruction Research Center, Department of Orthopedics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
Abolfazl Bagherifard - Bone and Joint Reconstruction Research Center, Department of Orthopedics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
Alireza Mirzaei - Bone and Joint Reconstruction Research Center, Department of Orthopedics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran

Objectives: Although the diffuse type of tenosynovial giant cell tumor (D-TGCT) is rare, bone involvement is common in such lesions. However, the optimal management of bone lesions in D -TGCT is not well-described. In this study, we reported the outcomes of total synovectomy, curettage, and bone grafting/cementation in the treatment of D-TGCT with subchondral bone involvement. We also described the prevalence, demographic, and characteristic features of the lesions.Methods: In a retrospective study, we included ۱۳ patients with D-TGCT of large joints and associated subchondral cyst/cyst-like bone lesions of ≥ ۵ mm that were managed with total synovectomy and curettage. Cavities with a bone defect of ≤ ۳۰ mm (n=۱۲) were filled with bone grafts. Cavities of > ۳۰ mm (n=۱) were augmented with bone cement. The limb function was evaluated by the Musculoskeletal Tumor Society (MSTS) score.Results: The study population consisted of ۶ (۴۶.۱%) males and ۷ (۵۳.۹%) females with a mean age of ۳۰ ± ۷.۹ years. The most frequent sites of involvement were the knees and ankle joints (n=۵ each, ۳۸.۵%). The mean followup of the patients was ۶۹.۲ ± ۳۲.۹ months. The mean MSTS score of the patients was obtained at ۹۸.۲ ± ۳.۲ (range ۹۰-۱۰۰). The D-TGCT recurred in two patients, both of which were in the synovium. Postoperative complications were three cases of transient pain and one case of knee joint stiffness. While no patient had an osteoarthritic change in preoperative radiographs, two patients had osteoarthritic change (grade II) in the last follow-up, one in the knee and one in the hip.Conclusion: Curettage and filling the defect with bone graft or cement are adequate treatments for managing bone lesions in D-TGCT. Level of evidence: IV

bone lesion, Curettage, Diffuse tenosynovial giant cell tumor, pigmented villonodular synovitis