Outcome of the Stryker® Trident 'All-Poly' constraint acetabular insert: a district general hospital experience

Constrained acetabular inserts are designed as revision solutions for unstable total hip arthroplasties to prevent dislocation and as a possible primary option for elderly patients at risk of recurrent dislocation.

Our aim was to establish clinical and radiological outcomes of an 'all-poly' constrained acetabular device and to highlight reasons for component failure.

We retrospectively reviewed our use of the Stryker® Trident 'all-poly' constrained acetabular insert between 2008 and 2013. All inserts were cemented directly into the acetabulum. Demographic data was collated. The indication for use of a constrained insert and postoperative complications were determined. Patients were reviewed clinically and underwent radiographic follow-up.

A total of 56 constrained inserts were utilised during the study period. Follow-up was for a minimum of 2 years (mean 4.0 years and range 2.0-6.8 years). The mean latest follow-up Oxford hip score was 34.6 (11-48). One postoperative superficial wound infection, 1 breakage of the constraining ring without clinical consequence and 1 recognised complication of liner failure at the bipolar interface were noted.

In the short to medium term, acetabular constraint offers a useful primary or revision option in patients at risk or with recurrent dislocation.