Large cohort study on prevention strategies for dislocation in total hip arthroplasty.

Background: Dislocation is a major complication of total hip arthroplasty (THA). This study aimed to assess the dislocation rate after THA using the combined strategy of using CT-based navigation, large diameter heads, and posterior soft tissue repair in a large cohort.

Methods: We included 1410 patients who had undergone primary cementless THA using the CT-based navigation system. The posterior approach was used by a single surgeon for all patients. The participants included 143 (10.1 %) men and 1267 (89.9 %) women, with a mean age of 65 years. The mean body mass index was 24 kg/m2. Additionally, the incidence rate of postoperative dislocation per year was calculated. The dislocation onset was classified as early when the dislocation occurred within 2 years of the primary THA and late when it occurred more than 2 years after the primary THA. Recurrence and revision rates in patients with dislocations were investigated.

Results: The postoperative dislocation rate was 0.56 % (8 patients). The mean time to dislocation onset was 11.2 (0.5-20.0) months postoperatively. All postoperative dislocations occurred in the early phase whereas none in the late phase, showing a significant difference (p < 0.01). Six (0.43 %) patients experienced recurrent dislocations or required revision.

Conclusions: THA using the combined strategy resulted in low dislocation rates, especially without late dislocation.