Severe damage of the femoral head after dislocation and difficult reduction maneuvers after total hip arthroplasty.

INTRODUCTION: Aseptic loosening associated with osteolysis and release of wear particles is the main reason for revision of total hip arthroplasty (THA). Damage of femoral heads is well known to increase the wear rate at the articulating surface. Instability and dislocation are serious complications and are the second most frequent reason for revision surgery after THA. In the present work the possible damaging of the femoral head as a result of difficult reduction maneuvers of dislocated THA should be investigated. PATIENTS AND METHODS: In three cases of total hip dislocation an open reduction was performed after dislocation of primary THA. Thereby one metal and two ceramic femoral heads were retrieved. Each head was analyzed macroscopically and by scanning electron microscopy (SEM) subsequently.
RESULTS: In the first case the SEM analysis revealed severe titanium deposits on the retrieved ceramic head in the case of repeated unsuccessful closed reduction maneuvers. In the second case the retrieved ceramic head showed multiple scratches and a spalling of the surface structure. In the third case the retrieved metal head presented a roughened surface and severe scratches at the articulating area. DISCUSSION: Difficult reduction maneuvers following total hip dislocation can lead to severe damaging of the femoral head associated with an increase of the surface roughness. While repeated reduction maneuvers can lead to metallic deposits and spalling of the surface of ceramic heads, severe scratches can occur at metal heads. The damaging of the femoral head at the articulating surface can lead to increased wear and subsequent aseptic implant loosening. Therefore, open joint reduction has to be considered in cases of difficult or unsuccessful closed reduction maneuvers to prevent severe femoral head damage which may cause an increased release of wear particles.