Clinical and radiological results after revision THA with distal locking stem: A cohort study of 44 patients

Abstract

BackgroundDistal locking stems were developed in response to some complex revision procedures in total hip arthroplasty (THA), providing better axial and rotational stability. The aim of the present study was to assess medium-term clinical and radiological results of treatment with last-generation distal locking stem. HypothesisOur hypothesis was that this implant provided a high survival rate. Material and MethodsA single-center retrospective observational study included all patients who underwent THA revision with distal locking stem between April 2013 and January 2015 in our university hospital. The implant was a curved distal-locking stem fully coated in grit-blasted titanium alloy and hydroxyapatite (HA) with a collar made of TiAlV. This concept is based on primary distal fixation by interlocking screws. The primary endpoint was surgical revision for implant exchange. ResultsA total of 47 procedures with distal locking stem were performed, 44 of which were included. Minimum follow-up was 5 years. Etiologies of revision comprised 25 femoral loosenings, 13 periprosthetic fractures, 3 infections, and 3 modular taper breakages. Six patients underwent re-revision (13%), with only 1 implant change (98% survival rate). Mean Harris and Oxford Hip scores at last follow-up were respectively 81±13.5 [range, 67.4–94.5] and 26±9⋅2 [range, 16.7–35.2]. Radiologically, no stem subsidence occurred, and bone ingrowth was obtained in all cases. DiscussionFully-coated distal locking stems showed a high survival rate. They provided strong initial fixation, allowing early full weight-bearing in these frail patients. Level of evidenceIV; retrospective series.