Abstract：
Extensor mechanism (EM) disruption is a rare but severe complication of total knee arthroplasty (TKA) that can greatly impair function. Treatment options for chronic patella tendon ruptures include primary repair, autograft augmentation, and reconstruction with allograft or synthetic material. Despite various techniques, failures can occur, and options for reconstruction after a failed allograft or mesh are limited, especially if the tibial component is well-fixed and cannot be easily removed, and if there is proximal tibial deficiency from a previous failed EM allograft. This case report presents a novel solution for revision EM reconstruction in a 72y.o. female patient with a history of multiple EM failures using an off-label Trabecular Metal Cone-Mesh-Cone (TM CMC) clamshell construct. The surgical procedure involved the removal of a non-viable allograft from the knee joint and the creation of a custom trabecular metal (TM) clamshell construct with a Marlex mesh graft in between the two TM implants. The customized TM cone was designed to cover the deficient anterior tibia and wrap around the ingrown TM cone. The Marlex mesh was cemented between the existing implant and the customized TM cone, and the construct was secured in place with two cancellous screws. The mesh was tunneled between soft tissue to prevent contact with the implant and rotated scar tissue was interposed to prevent abrasion of the mesh on the implant surfaces. The patient tolerated the procedure well and no complications were noted postoperatively. At a follow-up 12 months after the operation the patient remains satisfied with the result.
摘要：
伸张机制（EM）破坏是全膝关节置换术（TKA）的罕见但严重的并发症，可极大地损害功能。慢性髌骨肌腱断裂的治疗选择包括一期修复，自体移植增强,用同种异体移植或合成材料重建。尽管有各种技术，可能会发生故障，同种异体移植或网格失败后的重建选择有限，特别是如果胫骨组件固定良好且不易移除，以及先前失败的EM同种异体移植是否存在胫骨近端缺陷。此病例报告提出了一种新的解决方案，用于72.o。女性患者使用标签外的小梁金属锥-网-锥（TMCMC）蛤壳结构进行多次EM故障的历史。外科手术包括从膝关节上去除无活性的同种异体移植物，并在两个TM植入物之间创建带有Marlex网状移植物的定制小梁金属（TM）蛤壳结构。定制的TM锥被设计成覆盖不足的前胫骨并围绕向内生长的TM锥。Marlex网格被固定在现有的植入物和定制的TM锥体之间，结构用两个松质骨螺钉固定。将网状物隧穿在软组织之间以防止与植入物接触,并且插入旋转的疤痕组织以防止网状物在植入物表面上的磨损。患者对手术耐受性良好，术后无并发症。在手术后12个月的随访中，患者对结果仍然满意。
