Karthik M S, Mohammed Abrar, Parthasarathy Avinash
Department of Arthroplasty, Sanjay Gandhi Institute of Trauma and Orthopedics, Bengaluru, Karnataka, India.
J Orthop Case Rep. 2025 Sep;15(9):83-87. doi: 10.13107/jocr.2025.v15.i09.6024.
Heterotopic ossification (HO) is a rare complication following total knee replacement (TKR), with an incidence ranging between 1% and 3%. This condition can lead to significant functional limitations, including immobility and pain, particularly when ossification impinges on adjacent structures.
We report the case of a 67-year-old female with grade 4 osteoarthritis of the left knee who underwent TKR following the failure of conservative management. Postoperatively, the patient developed stiffness and a reduced range of motion. Radiographic imaging at 5 weeks showed haziness in the anterior aspect of the femur at the upper border of the femoral implant, with gradual progression to distinct ossification by 3 months.
The heterotopic bone formation was found to impinge on the quadriceps mechanism, limiting knee flexion but not preventing full extension. Conservative management involving physiotherapy and analgesics was pursued, and surgical excision was avoided initially. Over 1 year, the patient showed improvement in extension, although no significant improvement in flexion was observed. Surgical excision of the heterotopic bone was performed at the end of 1 year, followed by post-operative radiotherapy to prevent recurrence.
This case underscores the rarity of HO following TKR, particularly when it involves the quadriceps mechanism. It highlights the importance of early detection, close monitoring, and a stepwise treatment approach - starting with conservative therapy and escalating to surgical intervention when necessary. Post-operative radiotherapy can be considered in select cases to minimize recurrence.
异位骨化（HO）是全膝关节置换术（TKR）后一种罕见的并发症，发病率在1%至3%之间。这种情况会导致严重的功能受限，包括活动障碍和疼痛，尤其是当骨化压迫相邻结构时。
我们报告一例67岁左膝4级骨关节炎女性患者，在保守治疗失败后接受了全膝关节置换术。术后，患者出现膝关节僵硬和活动范围减小。术后5周的影像学检查显示股骨假体上缘前方股骨区域模糊，3个月时逐渐发展为明显的骨化。
发现异位骨形成压迫股四头肌机制，限制膝关节屈曲但不影响完全伸直。采取了包括物理治疗和止痛药物在内的保守治疗，最初避免了手术切除。经过1年，患者的伸直功能有所改善，但屈曲功能未见明显改善。1年后对异位骨进行了手术切除，术后进行放疗以防止复发。
该病例强调了全膝关节置换术后异位骨化的罕见性，尤其是当它累及股四头肌机制时。它突出了早期检测、密切监测以及逐步治疗方法的重要性——从保守治疗开始，必要时升级为手术干预。在特定病例中可考虑术后放疗以尽量减少复发。
