Clinical Orthopaedics and Related Research®

, Volume 470, Issue 12, pp 3515–3523

Acetabular Component Positioning Using Anatomic Landmarks of the Acetabulum

  • Yong-Chan Ha
  • Jeong Joon Yoo
  • Young-Kyun Lee
  • Jin Young Kim
  • Kyung-Hoi Koo
Clinical Research

DOI: 10.1007/s11999-012-2460-y

Cite this article as:
Ha, YC., Yoo, J.J., Lee, YK. et al. Clin Orthop Relat Res (2012) 470: 3515. doi:10.1007/s11999-012-2460-y

Abstract

Background

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.

Methods

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).

Results

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.

Conclusions

We obtained adequate cup position with our method and none of 45 patients (49 hips) had dislocation.

Level of Evidence

Level IV, therapeutic study. See Guidelines for Authors for a complete description of level of evidence.

Copyright information

© The Association of Bone and Joint Surgeons® 2012

Authors and Affiliations

  • Yong-Chan Ha
    • 1
  • Jeong Joon Yoo
    • 2
  • Young-Kyun Lee
    • 3
  • Jin Young Kim
    • 4
  • Kyung-Hoi Koo
    • 5
  1. 1.Department of Orthopaedic SurgeryChung-Ang University College of MedicineSeoulSouth Korea
  2. 2.Department of Orthopedic Surgery, Seoul National University College of MedicineSeoul National University HospitalSeoulSouth Korea
  3. 3.Department of Orthopaedic SurgerySeoul National University Bundang HospitalSeoulSouth Korea
  4. 4.Department of Orthopaedic SurgeryDongguk University College of MedicineGyeongjuSouth Korea
  5. 5.Department of Orthopaedic SurgerySeoul National University Bundang Hospital, Seoul National University College of MedicineSeoulSouth Korea

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