Mansat P, Briot J, Mansat M, Swider P
Service d'Orthopédie, Centre Hospitalier Universitaire de Toulouse, Toulouse, France.
J Shoulder Elbow Surg. 2007 May-Jun;16(3 Suppl):S79-83. doi: 10.1016/j.jse.2005.11.010. Epub 2006 Aug 7.
Total shoulder arthroplasty has become a successful surgical procedure through design improvements. However, lucent lines around the glenoid component are of major concern for leading to component loosening. To better understand the mechanism causing loosening, a finite element biomechanical model of an in vivo scapula was developed. The effect of eccentric loading was analyzed on a keel glenoid and a peg glenoid implant. Results indicated that eccentric loading greatly increases stresses in the cement mantle at the bone-cement interface, and no significant difference was predicted between keel and peg implants. The results suggested that eccentric loading is a likely cause for initiation of cracks in the cement layer especially on the posterior side. Moreover, these results, compared with other studies, indicate that geometric and bone properties of the scapula may be more important factors in the success of shoulder arthroplasty than implant design.
通过设计改进，全肩关节置换术已成为一种成功的外科手术。然而，肩胛盂假体周围的透亮线是导致假体松动的主要问题。为了更好地理解导致松动的机制，建立了一个体内肩胛骨的有限元生物力学模型。分析了偏心载荷对龙骨型肩胛盂和柱状肩胛盂植入物的影响。结果表明，偏心载荷会大大增加骨水泥界面处骨水泥套的应力，并且预测龙骨型和柱状植入物之间没有显著差异。结果表明，偏心载荷可能是导致骨水泥层尤其是后侧出现裂纹的原因。此外，与其他研究相比，这些结果表明，肩胛骨的几何形状和骨质特性可能比植入物设计更重要，是肩关节置换术成功的因素。
