Kow Ren Yi, Zainul-Abidin Suraya, Lo Woon Theng, Chen Xiu Fen, Liow Ming Han Lincoln
Department of Orthopaedics, Traumatology and Rehabilitation, International Islamic University Malaysia, Kuantan, MYS.
Department of Orthopaedic Surgery, Singapore General Hospital, Singapore, SGP.
Cureus. 2025 Feb 23;17(2):e79528. doi: 10.7759/cureus.79528. eCollection 2025 Feb.
Fibrous dysplasia (FD) is an uncommon, benign bone disorder caused by a somatic mutation in the GNAS gene on chromosome 20, leading to impaired osteoblastic differentiation and the replacement of normal bone with structurally weak, fibro-osseous tissue. It is typically diagnosed during childhood, though some cases remain undetected until incidentally discovered in adulthood. We present a patient with symptomatic knee osteoarthritis and an incidental finding of monostotic femur FD. The presence of FD in this anatomical location complicates an otherwise straightforward total knee arthroplasty (TKA). A bone biopsy was performed to rule out malignant transformation of the FD. The resulting bone defect posed a risk of periprosthetic fracture due to the stress riser created by the biopsy. A long femoral stem was used to mitigate this risk, and the patient recovered fully. This case underscores the critical importance of meticulous planning in managing patients with incidental findings of potential bone tumors. Biopsy site selection must consider definitive surgical management while avoiding pitfalls, such as periprosthetic fractures that may arise from stress risers created by biopsy site fenestration.
骨纤维异常增殖症（FD）是一种罕见的良性骨疾病，由20号染色体上GNAS基因的体细胞突变引起，导致成骨细胞分化受损，正常骨被结构薄弱的纤维骨组织替代。它通常在儿童期被诊断出来，不过有些病例直到成年期偶然发现才被察觉。我们报告了一例有症状性膝关节骨关节炎且偶然发现单发性股骨骨纤维异常增殖症的患者。该解剖部位存在骨纤维异常增殖症使原本简单的全膝关节置换术（TKA）变得复杂。进行了骨活检以排除骨纤维异常增殖症的恶变。活检造成的骨缺损因应力集中而带来假体周围骨折的风险。使用了长股骨干来降低这种风险，患者完全康复。该病例强调了在处理有潜在骨肿瘤偶然发现的患者时精心规划的至关重要性。活检部位的选择必须考虑最终的手术治疗，同时避免陷阱，比如活检部位开窗造成的应力集中可能引发的假体周围骨折。
