Background:

Femoral antetorsion in uncemented hip replacement hardly can be modified and the restoration of the anatomic anteversion might be difficult with standard stems. We compared femoral anteversion restoration of a generic straight stem with a proximally fixed anatomic stem that included a dual sagittal curvature and a proximal torsion. It was hypothesised that the restoration of the anteversion was more accurate with the anatomic stem.

Patients and methods:

In this comparative study data were collected prospectively of 80 consecutive patients with total hip arthroplasty for primary osteoarthritis. In the first 40 patients (Group I) a cementless proximally fixed anatomic stem with 15° antetorsion of the shaft and a dual sagittal curvature was used. Its design was based on a database of 3D CT images of 600 hips. For comparison a cementless generic straight double-tapered stem was implanted in the next 40 patients (Group II). All operations were performed by one experienced surgeon. All patients had a preoperative 3D planning. A low-dose CT scan was performed at 3 months postoperatively to determine the postoperative stem anteversion.

Results:

The demographics were similar in both groups. In group I the mean postoperative femoral anteversion was similar to the preoperative one (22.1° ± 10.2° vs. 20.4° ± 9°; p = 0.2). In Group II, the mean postoperative femoral anteversion was lower (12.9° ± 10.8°, vs. 18.3° ± 12°; p = 0.02).

Conclusions:

Uncemented standard femoral stems tend to reduce femoral anteversion. The used anatomic stem restored femoral anteversion better. The clinical impact of this finding has to be proven.

中文翻译：

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使用近端固定解剖柄进行全髋关节置换术后股骨前倾修复的准确性高于普通直双锥形柄

背景：

非骨水泥髋关节置换术中的股骨前倾很难改变，而标准股骨柄可能难以恢复解剖前倾。我们比较了普通直柄股骨前倾修复体与近端固定解剖柄，包括双矢状弯曲和近端扭转。假设使用解剖柄恢复前倾更准确。

患者和方法：

在这项比较研究中，前瞻性收集了 80 名原发性骨关节炎接受全髋关节置换术的连续患者的数据。在前 40 名患者（I 组）中，使用了具有 15° 轴前倾和双矢状曲率的无骨水泥近端固定解剖柄。它的设计基于 600 个臀部的 3D CT 图像数据库。为了比较，在接下来的 40 名患者（第 II 组）中植入了非骨水泥通用直双锥形柄。所有手术均由一位经验丰富的外科医生完成。所有患者都有术前 3D 计划。术后 3 个月进行低剂量 CT 扫描以确定术后茎前倾。

结果：

两组的人口统计数据相似。在第一组中，平均术后股骨前倾与术前相似（22.1° ± 10.2° vs. 20.4° ± 9°；p = 0.2）。在第二组中，平均术后股骨前倾较低（12.9°±10.8°，对 18.3°±12°；p = 0.02）。

结论：

未粘合的标准股骨柄倾向于减少股骨前倾。使用的解剖柄更好地恢复了股骨前倾。这一发现的临床影响必须得到证实。