Pelvic Tilt and the Pubic Symphysis to Sacrococcygeal Juncti
Dislocation after total hip arthroplasty (THA) is among the most common causes of early revision in contemporary practice. Abnormal spino-pelvic alignment increases risk for dislocation. Researchers sought to determine the effect of pelvic tilt, using a novel radiographic measurement, on dislocation risk by evaluating those with and without a history of dislocation.

Researchers identified 10,082 primary THA’s. Postoperatively, 177 dislocated (1.7%). Dislocators were matched 1:1 to control patients who did not dislocate. Pelvic tilt was calculated using the pubic symphysis to sacrococcygeal junction distance (PSCD) from a supine anteroposterior (AP) pelvis radiograph both pre- and postoperatively. The association between dislocation and both pelvic tilt and PSCD was then evaluated by logistic regression. Mean follow-up was 3 years.

Results:
--Patients who dislocated had more posterior pelvic tilt (mean pelvic tilt of 57° versus 60°) and smaller PSCD’s (mean 41 mm versus 46 mm) than controls.

--Patients with a PSCD less than 0 mm (symphysis above sacrococcygeal junction) had 9-fold odds of dislocation compared to those with a PSCD more than 50 (OR 9).

Finally, patients who dislocated their hips after primary THA had a higher posterior pelvic tilt. Furthermore, those with a PSCD of less than 0 had a 9-fold increased chance of dislocation. A positive PSCD should encourage further investigation or optimization of the pre-operative plan to mitigate dislocation risk, and a negative PSCD should encourage further investigation or optimization of the pre-operative plan to minimize dislocation risk.

Source: https://www.sciencedirect.com/science/article/abs/pii/S0883540321002394?dgcid=rss_sd_all
Like
Comment
Share