约有三分之一的近端肱骨肿瘤患者需要进行额外关节切除术以达到肿瘤学标准的切除范围。这种手术的功能结果差，复发率相当高。非约束性植入物容易发生不稳定，影响肘关节和手的功能，而受限制的肩关节重建手术由于骨负荷过重而早期发生无菌松动。本研究的目的是开发一种适用于额外关节切除术的受限制植入物，可以解决三角肌和旋转袖肌功能丧失的问题，并提供稳定性和被动运动，同时降低肩关节无菌松动的风险。在与布拉格捷克理工大学的合作下，我们设计了一个由两个串联的受限制关节连接的哑铃部件组成的植入物。生物力学分析显示，扭矩为8.6 Nm能够在骨螺丝上产生865N的拉力，而传递到肩胛骨组件的负荷仅为0.07 Nm，从而保护肩胛骨组件免受不希望的力，并降低无菌松动的风险。三例进行了额外关节切除术并且旋转袖肌和三角肌肌功能完全丧失的患者接受了这种重建手术。平均随访时间为16个月。手术技术简单明了。手术平均耗时175分钟，平均失血量为516毫升。没有手术或植入相关的并发症。三位患者在重建手术后肩关节稳定，无疼痛感。所有患者的肘关节、腕关节和手关节功能良好。平均肌肉骨骼肿瘤学会（MSTS）评分为21/30（70%）。所有患者对手术结果感到满意。这种创新的植入物设计在这些复杂病例中表现出有希望的替代方法。© 2023. BioMed Central Ltd., Springer Nature 的一部分。

Approximately, one-third of patients with tumors of proximal humerus will require an extra-articular resection to achieve oncologic margins. This procedure yields poor functional outcomes with a considerable rate of revisions. Unconstrained implants are prone to instability hindering also function of the elbow and hand, whereas constrained shoulder reconstructions suffer from early aseptic loosening of the glenoid component due to bone overload. The purpose of this study was to develop a constrained implant suitable for extra-articular resection with loss of function in deltoid and rotator cuff, which would provide both stability and passive motion, whilst also decreasing the risk of aseptic loosening of the glenoid component.In cooperation with Czech Technical University in Prague, we devised an implant consisting of two constrained joints in series connected by a dumbbell piece. The biomechanical analysis showed a reduction of load transfer to the glenoid component with a torque of 8.6 Nm capable of generating an 865-N pulling force on bone screw to just 0.07 Nm, hence shielding the glenoid component from undesired forces and decreasing the risk of aseptic loosening. Three patients with extra-articular resection with a total loss of function of both rotator cuff and deltoid muscle received this type of reconstruction. The average follow-up was 16 months.The surgical technique is straightforward. The surgery took 175 min on average with average blood loss of 516 ml. There were no surgical- or implant-related complications. All three patients were pain-free and had a stable shoulder joint after the reconstruction. All had fully functional elbow, wrist, and hand joints. The average Musculoskeletal Tumor Society (MSTS) score was 21/30 (70%). All patients were pleased with the results.The presented innovative implant design has demonstrated to be a promising alternative for reconstruction in these challenging cases.© 2023. BioMed Central Ltd., part of Springer Nature.