Grammont假体及其衍生反肩关节假体的生物力学研究进展

Biomechanical research progress of the Grammont prosthesis and its derivative reverse shoulder prostheses

反肩置换是治疗肩关节终末期退行性疾病和严重肩关节创伤的有效方法。早期研究者发现反肩假体在使用过程中可出现肩峰骨折、盂肱关节下方撞击及外旋受限等并发症。在肩关节活动过程中骨-植入体(关节盂-基座)界面之间的剪切力增加,易导致假体松动和脱位。为降低反肩置换术后并发症的发生率,改良反肩假体应运而生,并由此衍生出了多种假体,主要改良方向是外移假体系统的旋转中心。外移的旋转中心可设置于肩胛盂侧、肱骨侧或两侧同时改良。改良假体可根据外移部位和肱骨偏距大小进行分类。反肩假体的稳定性和运动能力依赖三角肌,即使肩袖发生损伤也不影响肩关节活动,因此患者术后满意度较高。通过固定的旋转中心这一非解剖学设计形成了半限制性的稳定结构,植入物的几何形态可使肱骨头和关节盂之间形成更稳定的关节,降低了肩盂假体松动和植入物失效的发生率。反肩置换并不适用于所有患者,对不存在明显肩袖功能障碍的患者来说,正肩置换仍是恢复自然解剖结构和肩关节运动学的首选手术方式。术者应综合分析患者功能状态、需求及个体解剖情况选择最佳手术方式。

Reverse shoulder arthroplasty is an effective method for treating end-stage degenerative shoulder diseases and severe shoulder trauma.Early researchers found that complications such as acromial fracture,inferior glenohumeral impingement,and external rotation limitation may occur during the use of reverse shoulder prosthesis.Additionally,during shoulder joint movements,the shear forces between the bone-implant(glenoid-baseplate)interface increase,leading to a higher risk of prosthesis loosening and dislocation.In order to reduce the incidence of complications after reverse shoulder arthroplasty,the modified reverse shoulder prosthesis was developed,and a variety of prostheses were derived from it.The main direction of improvement was to shift the rotation center of the prosthesis system.The center of rotation for external displacement can be set on the glenoid side of the scapula,the humeral side,or both sides simultaneously modified.Modified prostheses can be classified according to the site of external translation and the size of the humeral offset.The stability and movement ability of the reverse shoulder prosthesis depend on the deltoid muscle.Even if the rotator cuff is injured,it does not affect the shoulder joint movement,so the patient's postoperative satisfaction is high.Through the non-anatomical design of a fixed rotation center,a semi-restrictive stable structure is formed,and the implant geometry can form a more stable joint between the humeral head and the glenoid,reducing the incidence of glenoid prosthesis loosening and implant failure.Reverse shoulder arthroplasty is not suitable for all patients.For patients without significant rotator cuff dysfunction,forward shoulder arthroplasty is still the preferred surgical procedure to restore the natural anatomy and shoulder kinematics.Surgeons should conduct a comprehensive analysis of the patient's functional status,needs,and individual anatomy to determine the optimal surgical approach.