Department of Orthopaedics, St. Vinzenz-Krankenhaus, Schloßstraße 85, 40477, Düsseldorf, Germany.
Medical Faculty, University of Duisburg-Essen, Hufelandstraße 55, 45122, Essen, Germany.
Arch Orthop Trauma Surg. 2021 Jun;141(6):891-897. doi: 10.1007/s00402-020-03457-9. Epub 2020 May 30.
Inaccurate stem implantation can cause unsatisfactory offset reconstruction and may result in insufficient gluteal muscle function or aseptic loosening. In this study, stem alignment of a collarless straight tapered HA-coated stem was retrospectively analyzed during the learning phase of the direct anterior approach (DAA) for primary total hip arthroplasty (THA).
From Jan 2013 to Jun 2015, a total of 93 cementless THA were implanted in patients with unilateral coxarthrosis via the DAA in a two surgeon setting using the Corail or Trendhip stem (DePuy Synthes or Aesculap). Varus(+)/Valgus(-) stem alignment was analyzed in postoperative anteroposterior pelvic radiographs. Effects on femoral offset reconstruction and correlation to patient's individual clinical and radiological parameters were evaluated.
55 stems were implanted in varus (59%), 32 in neutral (34%) and 6 in valgus alignment (7%). Mean stem alignment in varus position was + 2.2° (SD ± 1.4°). Varus alignment was associated with male gender and preoperative coxa vara deformity: low CCD, high femoral offset and long thigh neck (p ≤ 0.001). Alignment was not correlated to femoral offset restoration, BMI or leg length difference. Mean cup inclination was 44° (SD ± 4.7°) and 90% matched the coronal Lewinnek safe zone.
In the learning curve, the DAA can be associated with a high incidence of varus stem alignment when using a straight tapered stem, especially in men with coxa vara deformity: low CCD, high femoral offset and long thigh neck. An insufficient capsule release makes femur exposure more difficult and might be an additional factor for this finding. We recommend intraoperative X-ray in the learning phase of the DAA to verify correct implant positioning and to adjust offset options.
不准确的植入物会导致不满意的偏心距重建，并可能导致臀肌功能不足或无菌性松动。在这项研究中，回顾性分析了直接前入路（DAA）初次全髋关节置换术（THA）学习阶段中无领直锥形 HA 涂层植入物的植入物位置。
2013 年 1 月至 2015 年 6 月，两位医生采用 DAA 在双侧髋关节骨关节炎患者中完成了 93 例非骨水泥 THA，使用 Corail 或 Trendhip 股骨柄（DePuy Synthes 或 Aesculap）。术后前后位骨盆 X 线片分析了内翻（+）/外翻（-）植入物位置。评估了股骨偏心距重建的效果，并与患者的个体临床和影像学参数相关。
55 个植入物为内翻（59%），32 个为中立（34%），6 个为外翻（7%）。内翻组的平均植入物位置为+2.2°（SD ± 1.4°）。内翻与男性和术前髋内翻畸形相关：低中心边缘角（CCD）、高股骨偏心距和大腿颈较长（p≤0.001）。植入物位置与股骨偏心距恢复、BMI 或肢体长度差异无关。平均杯倾斜度为 44°（SD ± 4.7°），90%与冠状 Lewinnek 安全区匹配。
在学习曲线中，使用直锥形股骨柄时，DAA 与高发生率的内翻植入物位置相关，尤其是在髋内翻畸形的男性中：低 CCD、高股骨偏心距和大腿颈较长。关节囊松解不充分会使股骨暴露更困难，这可能是造成这一发现的另一个因素。我们建议在 DAA 的学习阶段进行术中 X 射线检查，以验证植入物的正确位置，并调整偏心距选择。
