Prior hip instability was associated with a sevenfold increase in the odds of postoperative dislocation among patients undergoing isolated head and liner exchange, according to published results.
Elyse J. Berlinberg, BS, and colleagues from the department of orthopedics at NYU Langone Health retrospectively reviewed data on 209 patients (mean age of 64 years) who underwent isolated head and liner exchange with a minimum 2-year follow-up from June 24, 2011, to June 13, 2019.
Outcome measures included postoperative dislocation and functional cup positioning within the Lewinnek safe zone, which was assessed with postoperative weight-bearing radiographs. According to the study, common indications for surgery included acetabular liner wear (in 41% of patients), instability (in 19% of patients) and infection (in 17% of patients).
Among the cohort, 28 patients (13%) had a dislocation within 2 years after surgery. After analyzing best-fit models, researchers found history of dislocation (unadjusted OR = 7.25), age (unadjusted-OR = 1.06 per 1-year increase) and BMI (unadjusted-OR= 0.86 per 1 kg/m2 increase) were predictors of postoperative dislocation.
“This risk remains significant after controlling for cup positioning outside the Lewinnek safe zone, liner type, head size, neck length, soft tissue compromise, neuromuscular disease and dual mobility constructs,” the researchers wrote in the study. “Surgeons should use this information in shared decision-making to choose an appropriate approach to revision THA, balancing the appealing nature of a less complex surgery with a possible higher likelihood of further instability,” they concluded.