Impacts of external rotators and the ischiofemoral ligament on preventing excessive internal hip rotation: a cadaveric study

Kazuyoshi Baba, Daisuke Chiba, Yu Mori, Yoshiyuki Kuwahara, Atsushi Kogure, Takehiro Sugaya, Kumi Kamata, Itsuki Oizumi, Takayuki Suzuki, Hiroaki Kurishima, Soshi Hamada, Eiji Itoi, Toshimi Aizawa

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Background: This study examined the biomechanics of preventing excessive internal hip joint rotation related to the hip flexion angle. Method: An intramedullary nail with a circular plate equipped with a protractor was installed in the femur of nine normal hips. The circular plate was pulled by 3.15 Nm of force in the internal rotation direction. The external rotators were individually resected, finally cutting the ischiofemoral ligament. The cutting order of the external rotators differed on each side to individually determine the internal rotation resistance. The external rotators were resected from the piriformis to the obturator externus in the right hips and the reverse order in the left hips. Traction was performed after excising each muscle and ischiofemoral ligament. Measurements were taken at 0°, 30°, and 60° of hip flexion, and the differences from baseline were calculated. Results: For the right hip measurements, the piriformis and ischiofemoral ligament resection significantly differed at 0° of flexion (p = 0.02), each external rotator and the ischiofemoral ligament resections significantly differed at 30° of flexion (p < 0.01), and the ischiofemoral ligament and piriformis and inferior gemellus resections significantly differed at 60° of flexion (p = 0.04 and p = 0.02, respectively). In the left hips, the ischiofemoral ligament and obturator externus, inferior gemellus, and obturator internus resections significantly differed at 0° of flexion (p < 0.01, p < 0.01, and p = 0.01, respectively), as did each external rotator and the ischiofemoral ligament resections at 30° of flexion (p < 0.01). Conclusion: The ischiofemoral ligament primarily restricted the internal rotation of the hip joint. The piriformis and obturator internus may restrict internal rotation at 0° and 60° of flexion.

Original languageEnglish
Article number4
JournalJournal of Orthopaedic Surgery and Research
Volume17
Issue number1
DOIs
Publication statusPublished - 2022 Dec

Keywords

  • Cadaveric study
  • Capsular ligament
  • Dislocation
  • External rotator
  • Hip joint
  • Ischiofemoral ligament
  • Total hip arthroplasty

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