Introduction: Fractures of the neck of the femoral component have been reported in uncemented total hip replacements, however, to our knowledge, no fractures of the neck of a cementless forged titanium alloy femoral stem coated in the proximal third with hydroxy-apatite have been reported in the medical literature.

Case report, Level IV.

The head of an implanted hip joint endoprosthesis is exposed to torques, which are transferred during gait due to the friction between the head and the cup prosthesis. In prostheses with ceramic ball heads, which are widely used now, and in which the head is fixed onto the stem by conical clamping, these torques could possibly affect the connection. In this study, torques transferred from the cup to the head are compared to the torques which are required to loosen the head from the metallic spigot. The results show that for the investigated head and taper types and sizes, under normal conditions the connection is safe with respect to undesired rotation. However, it is shown that for polluted sliding surfaces the fixation strength could possibly be exceeded.

The complications of total hip arthroplasty (THA) during the immediate postoperative period consist mainly in dislocation of the prosthesis, haematomas under antocoagulants, early infections, dismantling of osteotomy, neurological injury, heterotopic ossification and delayed restoration of the range of motion of the hip joint. We present here an infrequently described case of haematoma of the pectineus muscle following THA. Haematomas are not described in literature except in rare cases of compressive haematoma associated with neurological injury. In our case, the intraoperative blood losses were not particularly massive, there were no anticoagulation accident or postoperative trauma and no secondary deglobulinization. The question to be considered is that of a possible stretching of the pectineus during hip dislocation, and possibly during the surgical procedures for the implementation of the prosthesis with increased length, as it is the case here. Haematomas of the pectineus are probably underdiagnosed as they imitate other, more known, symptomatologies.