Mulpur Praharsha, Jayakumar Tarun, Masilamani A B Suhas, Hippalgaonkar Kushal, Reddy A V Gurava
Department of Orthopeadic, Sunshine Bone and Joint Institute, Sunshine Hospitals, Hyderabad, Telangana, India.
J Orthop Case Rep. 2022 Dec;12(12):25-29. doi: 10.13107/jocr.2022.v12.i12.3450.
The use of modular implants for revision TKA are ever increasing in number due to their definitive advantage over their monoblock counterparts by providing the surgeon with the versatility needed to achieve equal gaps and manage bone defects. This superiority comes at the cost of certain unique complications attributable to its modular design such as loosening and fractures at the areas of component coupling that are prone to fatigue failure with suboptimal fixation.
We present a case of modular femoral component failure in a 59-year man of Asian decent after revision TKA secondary to disengagement and migration of the extension stem locking bolt of a Total Condylar-III prosthesis. Patient presented with pain, effusion, and instability 2.5 years after stage-2 revision TKA. Radiographs revealed migration of the femur-stem locking bolt into the joint cavity. The femoral component and stem were loose. The locking bolt was extracted, and he underwent re-revision surgery with revised femoral components.
Stem-condylar junction of modern modular TKA implants are prone to early loosening and failure. This diagnosis should be anticipated on serial follow-up radiographs and in patients who complain of sudden onset of instability following revision surgery.
由于模块化植入物相对于整体式植入物具有明显优势，可为外科医生提供实现等距间隙和处理骨缺损所需的通用性，因此在翻修全膝关节置换术（TKA）中的使用数量不断增加。这种优越性是以某些因模块化设计导致的独特并发症为代价的，例如在部件连接区域出现松动和骨折，这些区域在固定欠佳时容易发生疲劳失效。
我们报告一例59岁亚洲裔男性在翻修TKA后出现模块化股骨部件故障的病例，该故障继发于全髁III型假体的延长柄锁定螺栓脱开和移位。患者在二期翻修TKA术后2.5年出现疼痛、积液和不稳定症状。X线片显示股骨柄锁定螺栓移入关节腔。股骨部件和柄松动。取出锁定螺栓后，患者接受了使用修订后股骨部件的再次翻修手术。
现代模块化TKA植入物的柄-髁交界处容易早期松动和失效。在系列随访X线片以及翻修手术后抱怨突然出现不稳定的患者中应预见到这种诊断。
