P87. Contemporary guidelines for acetabular positioning in hip arthroplasty may jeopardize hip dislocation for select ASD patients

Lewinnek et al previously defined a safe zone for cup inclination (40° ± 10°) and anteversion (15° ± 10°) to reduce dislocations after total hip arthroplasty (THA). Despite the Lewinnek safe zone being respected, higher rates of prosthetic dislocation are found in ASD patients undergoing THA. This s...

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Published in:The spine journal 2024-09, Vol.24 (9), p.S104-S105
Main Authors: Boutros, Marc, Daher, Mohammad, Assi, Ayman, Prince, Gilles, Karam, Mohammad, Ames, Christopher P., Bess, Shay, Daniels, Alan H, Gupta, Munish C, Hostin, Richard A., Kelly, Michael P., Kim, Han Jo, Klineberg, Eric O., Lenke, Lawrence G., Nunley, Pierce D, Passias, Peter Gust, Schwab, Frank J., Shaffrey, Christopher I., Smith, Justin S., Lafage, Renaud, Diebo, Bassel G., Lafage, Virginie
Format: Article
Language:English
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Summary:Lewinnek et al previously defined a safe zone for cup inclination (40° ± 10°) and anteversion (15° ± 10°) to reduce dislocations after total hip arthroplasty (THA). Despite the Lewinnek safe zone being respected, higher rates of prosthetic dislocation are found in ASD patients undergoing THA. This study aims to investigate if ASD patients with high PT need a specific safe zone for acetabular positioning. Retrospective analysis of prospectively collected data. ASD patients with moderate to severe sagittal deformity and full-body xrays and a detailed 3D reconstruction of the pelvis and lower limbs in standing position preop. Radiographic spinal and acetabular parameters The PI-adjusted PT was calculated using Vialle et al formula (adj.PT=0.37*PI-7°) and patients with PT> adj.PT were grouped as HighPT, otherwise as NormPT. Spino-pelvic, 3D acetabular parameters were compared between the groups. PT offset from adj.PT was calculated. The number of patients falling outside the Lewinnek safe zone between the 4 quartiles of PT offset was compared. A linear regression analysis was performed to assess the relationship between PT and acetabular parameters. A total of 132 patients were included (HighPT:86, NormPT:46) with no differences in age, sex, comorbidities, and hip OA grades between the groups. HighPT had higher PI-LL (32.1, 12.4°), SVA (79.7, 59.0 mm), T1PA (31.2, 19.5°), SFA (209.1, 199.3°), pelvic Shift (50.3, 17.2 mm), GSA (7.6, 4.5°), and L4-S1 lordosis (26.2, 34.5°; all p
ISSN:1529-9430
DOI:10.1016/j.spinee.2024.06.108