The New Mexico Center for Joint Replacement Surgery, New Mexico Orthopaedics, 201 Cedar SE, Suite 6600, Albuquerque, NM 87106, USA.
Clin Orthop Relat Res. 2011 Feb;469(2):443-6. doi: 10.1007/s11999-010-1678-9.
Restoration of hip offset and leg length during THA is often limited by available implant geometries. The recent introduction of femoral components with a modular junction at the base of the neck (two modular junction components) has expanded the options to restore femoral offset and leg length.
QUESTIONS/PURPOSES: We asked (1) whether a femoral component with two modular junctions would predict by templating more frequent restoration of preoperative offset and leg length abnormalities than one with single modular junctions; and (2) how our use of these options compared with national sales data.
We retrospectively reviewed the preoperative templating data in 100 primary THAs using single modular junction implants with only a neutral version stem and 100 THAs using two modular junction implants. We compared the frequency with which the desired leg length and offset were completely restored by preoperative templating in the two groups.
Offset and leg lengths were restored to within 1 mm in 85% of cases with two modular junction implants and 60% of cases with single modular junction implants. An anteverted or a retroverted neck was used in 25% of cases with the two modular junction stems. The national sales data revealed femoral neck components with version were used in 28% of cases.
The use of a femoral component with two modular junctions resulted in more frequent ability to restore femoral offset and leg length than a single modular junction. The advantage of clinical flexibility should be tempered by the potential concerns of prosthetic mechanical failure (which has been reported in another implant system with two modular junctions), increased third-body wear and corrosive debris, and increased prosthetic cost.
Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
全髋关节置换术（THA）中髋关节的偏心距和下肢长度的恢复常常受到可用植入物几何形状的限制。最近，在颈部底部引入了具有模块化连接的股骨组件（两个模块化连接组件），这扩大了恢复股骨偏心距和下肢长度的选择范围。
问题/目的：我们询问了（1）与具有单一模块化连接的股骨组件相比，具有两个模块化连接的股骨组件是否通过模板预测更频繁地恢复术前偏心距和下肢长度异常；以及（2）与全国销售数据相比，我们如何使用这些选择。
我们回顾性地研究了使用单一模块化连接植入物（仅具有中性版本的干骺端）的 100 例初次 THA 和使用两个模块化连接植入物的 100 例 THA 的术前模板数据。我们比较了两组中通过术前模板完全恢复所需下肢长度和偏心距的频率。
使用两个模块化连接植入物，85%的病例恢复到偏心距和下肢长度在 1mm 以内，而使用单一模块化连接植入物的病例为 60%。在使用两个模块化连接干骺端的病例中，25%的病例使用了前旋或后旋的颈部。全国销售数据显示，使用了带有版本的股骨颈组件的病例占 28%。
与使用单一模块化连接相比，使用具有两个模块化连接的股骨组件更频繁地能够恢复股骨偏心距和下肢长度。临床灵活性的优势应受到假体机械失效的潜在担忧（在另一种具有两个模块化连接的植入系统中已有报道）、增加的第三体磨损和腐蚀性碎片以及增加的假体成本的影响。
II 级，预后研究。有关证据水平的完整描述，请参见作者指南。
