Lewinnek zone not “the be-all and end-all” functional planning for acetabular component positioning in total hip arthroplasty
2025

Functional Planning for Hip Surgery

Sample size: 100 publication Evidence: moderate

Author Information

Author(s): Iorio Raffaele, Viglietta Edoardo, Corsetti Federico, Gugliotta Yuri, Massafra Carlo, Polverari Daniele, Redler Andrea

Primary Institution: Sant’Andrea Hospital, Faculty of Medicine and Psychology, Sapienza University of Rome

Hypothesis

A mismatch does exist between the Lewinnek Safe Zone and the acetabular cup position suggested by the patient’s specific functional planning.

Conclusion

The Lewinnek Safe Zone does not correspond to the patient’s functional safe zone in about 8% of patients.

Supporting Evidence

  • The mean suggested inclination was 39° ± 3°.
  • The mean suggested anteversion was 21° ± 3°.
  • Only one patient had their functional acetabular inclination correspond to the LSZ.
  • Eight patients had acetabular anteversion outside the LSZ.

Takeaway

When doctors plan hip surgery, they need to consider each patient's unique body position, as the standard safe zone doesn't work for everyone.

Methodology

This was an IRB-approved, prospective cohort, observational imaging study involving 100 patients with primary hip osteoarthritis undergoing THA with personalized functional planning.

Limitations

The study did not correlate dislocation rates with cup positions and had a limited number of patients.

Participant Demographics

The mean age was 74 years, with 53% females and a mean BMI of 24.3.

Digital Object Identifier (DOI)

10.1186/s42836-024-00284-w

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