Hip international : the journal of clinical and experimental research on hip pathology and therapy
-
Comparative Study
Cup inclination angle of greater than 50 degrees increases whole blood concentrations of cobalt and chromium ions after metal-on-metal hip resurfacing.
A cup inclination angle greater than 45 degrees is associated with increased wear rates of metal on polyethylene (MOP) hip replacements. The same maybe true for metal on metal (MOM) hips yet this has not been clearly shown. We measured the acetabular inclination angle from plain radiographs, and whole blood metal ion levels using Inductively Coupled Plasma Mass Spectrometry of 26 patients (mean Harris Hip Score 94 and mean time post op of 22 months) with Birmingham Hip Resurfacings. ⋯ The effect of an acetabular inclination angle of greater than 50 degrees on wear rates of MOM hips, as measured through blood metal ion levels, appears to be similar to that seen with MOP hips. Additionally, our new analytical methods may allow blood metal levels to be used as a realistic biomarker of in vivo wear rate of MOM hips. The implication is that metal levels can be minimised with optimal orientation of the acetabular component.
-
Vascular complications following internal fixation of trochanteric femoral fractures are extremely rare. Iatrogenic injury to the profunda femoris artery or one of its branches and resultant pseudoaneurysm formation has been documented, most commonly following sliding hip screw fixation and typically arises on the posteromedial aspect of the femur. We report an unusual variation, following proximal femoral nailing of an intertrochanteric femoral neck fracture, where the pseudoaneurysm presented four weeks following surgery on the posterolateral aspect of the femur. The mechanism of injury, clinical presentation and potential preventative measures are discussed.