Peri-acetabular external fixation for hip disease: an anatomical study

Area of Science:

• Orthopaedic surgery
• Biomechanical engineering
• Anatomy

Background:

• Hip distraction with external fixation is an alternative to hip arthroplasty/arthrodesis for young adults with osteoarthritis, chondrolysis, or osteonecrosis.
• The hip's deep location, surrounding muscles, and proximity to neurovascular structures make external fixation challenging.
• Limited data exists on technical details and complications of hip external fixation.

Purpose of the Study:

• To identify safe screw insertion points in the periacetabular region for hip external fixation.
• To enhance the safety and efficacy of hip distraction techniques in adolescent and young adult patients.

Main Methods:

• Utilized CT scans and computer modeling to analyze hip and pelvic anatomy.
• Simulated surgical pin insertion on five cadavers.
• Performed anatomical dissections to verify pin positions and identify at-risk structures.

Main Results:

• Identified anatomical constraints for screw placement in the periacetabular region.
• Demonstrated the possibility of inserting three divergent pins within the available bony corridor.
• Highlighted the risk to the sciatic nerve from posterior laterally inserted pins if not angled correctly.

Conclusions:

• Safe screw placement for hip external fixation is achievable with careful anatomical consideration.
• Understanding anatomical risks, particularly to the sciatic nerve, is vital for successful application.
• This research provides critical anatomical guidance for orthopaedic surgeons using hip distraction external fixation.