Dysplasia_Clinical.xlsx

Abstract

Background: Arthritis
secondary to developmental hip dysplasia often mandates implant surgery at a
relatively young age. Hip resurfacing arthroplasty (HRA), compared with
standard stemmed total hip arthroplasty (THA), affords a more active lifestyle
including extreme-motion activities but stimulates concerns pertaining to
implant failure.

Methods: We addressed the
primary modes of failure through a series of interventions, including a new
guideline for achieving proper implant alignment through intraoperative x-rays.
We then compared two sequential cohorts in a single-surgeon practice: patients
with developmental dysplasia who underwent HRA before (Group 1; 121 hips in 105
patients) and after (Group 2; 242 hips in 210 patients) June 2008, at which
time the four interventions were all in place.

Results: Implants
in Group 2 failed less frequently within two years (0.8% vs. 6.6%, p = 0.002)
and were more likely to have projected seven-year Kaplan-Meier survivorship
(99% vs. 89%, p < 0.0001 by log-rank test). Patients in Group 2 were more
likely to have normal metal ion levels (77% vs. 56%, p = 0.0008) and optimum
metal ion levels (99% vs. 86%, p = 0.0008). Patients in Group 2 also benefited
from a 19-minute decrease in mean operation time, a 45% decrease in mean
estimated blood loss, and a 0.9-day decrease in mean hospital stay (p < 0.0001
in each instance).

Conclusions: We
believe the interventions reported here, combined with sufficient surgeon
experience and properly designed implants, afford patients with developmental
dysplasia a more active lifestyle with favorable implant survival.