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Assessment of acetabular version in total hip arthroplasty: an application of Widmer's technique in a regional setting
Author(s) -
Trieu Jason,
Hadden Alexandra E. F.,
Sutherland Alasdair G.
Publication year - 2018
Publication title -
anz journal of surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.426
H-Index - 70
eISSN - 1445-2197
pISSN - 1445-1433
DOI - 10.1111/ans.14506
Subject(s) - medicine , prosthesis , radiography , statistical significance , total hip arthroplasty , acetabulum , orthodontics , arthroplasty , statistical analysis , surgery , nuclear medicine , dentistry , statistics , mathematics
Background Acetabular prosthesis positioning in total hip arthroplasty is important in reducing the risk of dislocation. Assessment of version by computed tomography scan is expensive and involves a large radiation dose. We wished to assess the value of Widmer's technique, utilizing readily available radiographs, to determine cup anteversion. Methods Patients who underwent primary total hip arthroplasty by the senior author (AGS) at a single regional hospital over a 5‐year period were eligible for inclusion. Measurements were performed using the technique described by Widmer, utilizing standard post‐operative radiographs. Statistical analysis was undertaken in SPSS v22. Significance was accepted at P < 0.05. Results Assessment included 109 hips in 99 patients; 63 hips with cemented cups and 46 hips with uncemented cups. Mean acetabular anteversion in the cemented group was 11.9° (0–27.7, SD: 7) and in the uncemented group was 14.1° (10.3–32.7, SD: 7.1); this difference trended towards statistical significance ( P = 0.09). Test–retest measurements showed high degree of correlation (Pearson test: 0.927, P < 0.001). There were 96 of 109 hips positioned in the Lewinnek safe zone of 5–25° anteversion. The crude dislocation rate in our cohort was 6.4% (7 of 109 hips) with all dislocations occurring in hips placed in the safe zone. Conclusion Widmer's technique is a reliable method for calculating acetabular version in a regional hospital setting and offers the individual surgeon a ready technique of personal quality control. Cup version was not a significant factor contributing to dislocation rates in our series.