Systematic measurement of spino-pelvic alignment as a simple strategy to reduce the dislocation rate in primary hip arthroplasties.

Background: The incorporation of spinopelvic alignment measurement in the planning of primary hip arthroplasties is a simple and low-cost method whose isolated impact on reducing dislocation rates has not been clearly established.

Aim: The objective was to estimate the probability of dislocation and its occurrence rate by comparing 2 demographically similar populations, 1 with the measurement incorporated and the other without it. Additionally, the modification and distribution of surgical practices and indications aimed at reducing the risk of dislocations were compared.

Methods: A before-and-after study with prospective registry and retrospective control group was designed. We compared 693 patients (prospective registry) with the incorporation of spinopelvic alignment measurement in preoperative planning versus 341 from a previous period who constituted the control group (retrospective registry). All had a minimum follow-up of 2 years.

Results: The dislocation rate significantly decreased from 3.2% to 0.7%, with an OR of 0.22 for dislocation in the intervention group. There was a significant increase in the use of dual-mobility components in patients with complete misalignment and stems with extended offset in patients with partial misalignment.

Conclusions: In conclusion, the incorporation of spinopelvic alignment measurement in preoperative planning is an accessible method for any medical centre that contributed to modifying surgical practices, ultimately leading to a significant reduction in the dislocation rate.