Shah Sneh, Mulpur Praharsha, Vecham Ratnakar, Jayakumar Tarun, Hippalgaonkar Kushal
Department of Orthopaedics, Sunshine Bone and Joint Institute, KIMS-Sunshine Hospitals, Hyderabad, Telangana, India.
J Orthop Case Rep. 2023 Oct;13(10):127-131. doi: 10.13107/jocr.2023.v13.i10.3962.
Posterior-stabilized (PS) total knee arthroplasty (TKA) prostheses are characterized by an articulation between the polyethylene tibial post and the cam of the femoral component. Tibial post-fractures, traumatic and non-traumatic, are uncommon but catastrophic complications. We report a rare and unusual case of complete atraumatic erosion of the tibial post after PS-TKA.
We present a case of atraumatic tibial post-failure (complete erosion) in a 73-year-old female after primary TKA. The patient presented with chronic pain, effusion, and instability both in the coronal and sagittal plane over a period of 1 year. There were no signs of component loosening on plain radiography, no fractures, and revealed medial extension laxity on valgus stress views. During revision surgery, polyethylene insert retrieval revealed a completely eroded tibial post, without any obvious fracture. There was no fractured tibial post lying freely in the joint cavity. The patient was subsequently revised with a hinged component due to gross bi-planar instability.
In a post-TKR (PS knee) patient with chronic pain and instability, one should consider tibial post-complications after ruling out infection. Chronic instability can cause progressive erosion of the tibial post, which can fail without an obvious fracture. Revision surgery with constrained implants may be needed to manage such cases.
后稳定型（PS）全膝关节置换术（TKA）假体的特点是聚乙烯胫骨柱与股骨部件的凸轮之间存在关节连接。胫骨柱骨折，无论是创伤性还是非创伤性的，都不常见但却是灾难性的并发症。我们报告了一例PS-TKA术后罕见且不寻常的胫骨柱完全无创伤性侵蚀病例。
我们呈现了一名73岁女性在初次TKA术后出现无创伤性胫骨柱失效（完全侵蚀）的病例。患者在1年的时间里出现慢性疼痛、积液以及冠状面和矢状面的不稳定。X线平片上没有假体松动的迹象，没有骨折，外翻应力位片显示内侧伸展松弛。在翻修手术中，取出的聚乙烯衬垫显示胫骨柱完全被侵蚀，没有任何明显骨折。关节腔内没有游离的骨折胫骨柱。由于严重的双平面不稳定，患者随后接受了铰链式部件翻修。
在全膝关节置换术后（PS膝关节）出现慢性疼痛和不稳定的患者中，排除感染后应考虑胫骨柱并发症。慢性不稳定可导致胫骨柱逐渐侵蚀，可能在没有明显骨折的情况下失效。对于此类病例，可能需要使用限制性植入物进行翻修手术。
