Retrospective multi-centre study on head adapters in partial revision hip arthroplasty

Instability and dislocation after total hip arthroplasty (THA) is a common reason for revision surgery. THA head-neck adapters promise the reconstruction of optimal femoral offset and leg length in revision THA (rTHA) while retaining stable implants. The aim of this retrospective multi-centre study is to report on the results achieved with the use of head adapters in partial rTHA, to avoid the instability of the implant.

55 cases of partial rTHA performed between February 2015 and April 2017 in 3 different hospitals using the Bioball Head Adapter (BHA) (Bioball Merete, Medical GmbH, Berlin, Germany) were retrospectively recorded. All patients were evaluated from a radiological point of view at an average follow-up of 3.5 years. Failure was defined as re-revision surgery for any cause as well as a subjective feeling of instability of the joint.

One failure was registered in an extreme case and radiological findings show no suggestive signs of radiolucencies or loosening and therefore all implants have been considered stable.

Despite some limitations of this retrospective study and according to the relevant literature, our data confirms that BHA is a safe system that allows the flexibility to restore femoral offset and version, to adjust leg length, to minimise instability, to avoid unnecessary removal of otherwise well-fixed components thus improving tribology and reducing the risk of taper junction issues without major complications in partial rTHA.