|Beitragstitel||Early intra-prosthetic hip dislocation in dual mobility implant: an unusual complication.|
Dual mobility implants are useful tools for preventing hip dislocation in primary and revision hip prosthesis. These devices have numerous advantages, but can also bring extra complications. One of these complications is the intra-prosthetic dislocation. Literature show few publications about late dislocation due to wear retention of the cup; early dislocation however is much less common, with very few data describing this phenomenon. We describe an intra-prosthetic dislocation linked to a reduction manoeuvre and document this case exclusively with scannographic and intraoperative images.
A 78-year-old woman presented a first dislocation 6 days after revision of her total hip prosthesis with total dual mobility implants. Initial closed reduction was uneventful, but the hip felt unstable. The standard radiographies after reduction showed no anomaly, with a head centred in the acetabular implant. We therefore performed a CT-scanner of the pelvis showing an intra-prosthetic dislocation of the dual mobility hip implant.
Decision was made for revision of the hip prosthesis, finding the liner in the great gluteal muscle, detached from its initial position between the neck and shell. We opted for reorientation of the acetabular implant with another dual mobility hip implant. Postoperative clinical and radiographic controls were satisfactory, without any complication. Harris Hip Score was 82 at 2-year postoperative.
Dual mobility implants are good solutions to reduce the risk of hip prosthesis dislocation, but increase the potential number of complications due to an increase of interfaces. In case of dislocation of such an implant, we recommend to do closed reduction under general anaesthesia reducing the risk of intra-prosthetic dislocation. Dealing with an irreducible prosthesis dislocation with a dual mobility implant, we recommend to do a CT-scan to exclude a intra prosthetic implant dislocation.