Primary HipReduction in Offset Is Associated With Worse Functional Outcomes Following Total Hip Arthroplasty
Section snippets
Study Population
The St Vincent’s Melbourne Arthroplasty Outcomes Registry is an institutional, prospective database which includes all elective hip arthroplasty patients undertaken at the hospital since 1998 [5]. Twelve-month follow-up of patient-reported outcomes is >98% [5]. The study population included all registry participants presenting between January 1, 2012 and December 31, 2016 for elective, unilateral primary THA for any diagnosis, with minimal osteoarthritis of the contralateral hip
Radiological Measurements
The mean postoperative offset for the study population was reduced by 3.38 mm (range −43.50 to 92.53) compared to the native contralateral side, with a similar median of 3.77 mm (25th percentile = −12.70, 75th percentile = 5.58). Offset was within 10 mm of the contralateral side in 224 patients (54.1%), with 126 patients (30.4%) having offset decreased by >10 mm, and 64 patients (15.5%) having offset increased by >10 mm (Fig. 3).
Clinical and Functional Outcomes
The results of the WOMAC and VR-12 functional scores at the
Discussion
Accurate restoration of offset continues to be a cause of controversy for surgeons, despite being studied for well over 40 years [14]. This study evaluated the effects of offset following THA on pain and functional outcomes from prospectively collected registry data with 12-month follow-up, and found that patients who had offset decreased by 20 mm or more had worse pain, motion, and global WOMAC scores, and those with offset decreased between −10.00 and −0.01 mm had worse motion WOMAC scores.
Conclusion
This study demonstrated an association between reduction in offset by >20 mm and worse WOMAC pain and motion scores following THA. Surgeons should avoid decreases in offset >20 mm in order to optimize functional outcomes.
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One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to https://doi.org/10.1016/j.arth.2022.09.001.