Dislocation Risk not observed due to Posterior Pelvic Tilt R
Pelvic tilt affects acetabular anteversion, and thus THA dislocation risk. The pubic symphysis-sacrococcygeal distance (PSCD) is an indicator of pelvic tilt, and a PSCD less than 0mm is associated with a 3.7-fold increase in post-operative dislocation rate.

Standing AP radiographs were reviewed for 510 consecutive DA THAs to determine PSCD. Patients were separated into two groups: 1) PSCD more than 0mm (PSCD[+]) and 2) PSCD less than 0mm (PSCD[-]). Incidence of dislocation was determined. If patients had spinal deformity or lumbar fusion was recorded. Continuous variables were analyzed using Student’s t-test, categorical variables were analyzed using Fisher’s exact test, and a sample size calculation was performed.

--358 hips were PSCD[+], while 152 hips were PSCD[-].

--Three dislocations (3/510 hips) occurred. Two dislocators were in the PSCD[-] group (2/152 hips); one dislocator was in the PSCD[+] group (1/358 hips).

--24 patients had degenerative scoliosis (24/510), of which one had a dislocation (1/24); two dislocations occurred in non-scoliosis patients (2/486).

--27 patients had lumbar spinal fusion (27/510), of which there were no dislocations (0/27); all dislocations were in non-fusion patients (3/483).

Finally, no greater risk of THA dislocation was found in patients who underwent a DA approach and had a PSCD less than 0mm. These findings imply that the DA strategy protects against dislocation, especially in historically high-risk populations.

Source: https://www.sciencedirect.com/science/article/abs/pii/S0883540321005933?dgcid=rss_sd_all