Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, Seoul, South Korea.
Clin Orthop Relat Res. 2012 Dec;470(12):3515-23. doi: 10.1007/s11999-012-2460-y. Epub 2012 Jul 10.
The acetabular cup should be properly oriented to prevent dislocation and to reduce wear. However, achieving proper cup placement is challenging with potentially large variations of cup position. We propose a new technique to position the acetabular cup.
QUESTIONS/PURPOSES: We used this technique, then determined actual cup position and subsequent dislocation rate.
We measured acetabular abduction (α°) and anteversion (β°) on preoperative CT scans in 46 patients (50 hips) scheduled for THA. During the operation, we identified the transverse acetabular notch (TAN) and anterior acetabular notch (AAN), a notch at the anterior acetabular margin. We then marked two reference points for 40° abduction at the acetabular rim: the superior point, which is opposite the TAN, and the inferior point at |α - 40| mm inside (when α was > 40°) or outside the TAN (when α was < 40°). We also marked two reference points for 15° anteversion: the posterior point opposite the AAN and the anterior point at |β - 15| mm inside (when β was < 15°) or outside the AAN (when β was > 15°). During cup insertion, we aligned cup abduction to the line between the superior and inferior points and cup anteversion to the line between the anterior and posterior points. We measured cup abduction and anteversion and evaluated the dislocation rate. One patient was lost to followup before 60 months; the minimum followup for the other 45 patients was 60 months (mean, 62.8 months; range, 60-65 months).
The mean cup abduction was 40° (range, 32°-47°) and the mean cup anteversion was 17° (range, 8°-25°). No dislocation occurred postoperatively in 49 hips (45 patients) for a minimum of 5 years followup.
We obtained adequate cup position with our method and none of 45 patients (49 hips) had dislocation.
Level IV, therapeutic study. See Guidelines for Authors for a complete description of level of evidence.
髋臼杯应正确定位，以防止脱位并减少磨损。然而，由于髋臼杯位置存在较大变化，因此实现正确的杯置放具有挑战性。我们提出了一种新的髋臼杯定位技术。
问题/目的：我们使用了该技术，然后确定了实际的杯置位和随后的脱位率。
我们对计划行全髋关节置换术（THA）的 46 例患者（50 髋）的术前 CT 扫描测量髋臼外展角（α°）和前倾角（β°）。术中，我们确定了髋臼横切迹（TAN）和前髋臼切迹（AAN），即髋臼前缘的切迹。然后，我们在髋臼边缘标记了两个用于 40°外展的参考点：与 TAN 相对的上点和在 TAN 内（当 α>40°时）或 TAN 外（当 α<40°时）距 |α-40|mm 处的下点。我们还标记了两个用于 15°前倾角的参考点：与 AAN 相对的后点和在 AAN 内（当 β<15°时）或 AAN 外（当 β>15°时）距 |β-15|mm 处的前点。在杯插入过程中，我们使杯外展对线与上点和下点之间的线对齐，并使杯前倾角对线与前点和后点之间的线对齐。我们测量了杯的外展角和前倾角，并评估了脱位率。有 1 例患者在 60 个月前失访，其余 45 例患者的随访时间最短为 60 个月（平均 62.8 个月；范围，60-65 个月）。
平均杯外展角为 40°（范围，32°-47°），平均杯前倾角为 17°（范围，8°-25°）。45 例患者（49 髋）在至少 5 年的随访中均未出现术后脱位。
我们使用该方法获得了足够的杯置位，且 45 例患者（49 髋）中无一例发生脱位。
IV 级，治疗研究。有关证据水平的完整描述，请参见作者指南。
