Fracture of the cobalt-chromium modular femoral neck component in total hip arthroplasty.

Total hip prostheses using cervico-metaphyseal modularity were designed to better replicate the geometry of the native extra-medullary femur. However, they are associated with numerous complications including corrosion, disassembly, pseudotumours and, most notably, fractures of the modular neck. All reported cases of modular neck fractures occurred with titanium components (Ti-6Al-4V).

Mid-term outcomes after distally locked-to-standard primary stem exchange in 29 hip-prosthesis patients.

Background: Cementless locked femoral stems are used for revision surgery in patients with bone loss to induce spontaneous bone reconstruction, allowing subsequent replacement by a standard primary stem. The small number of patients and short follow-ups available to date preclude a valid assessment of this strategy.

Hypothesis: After distally locked stem revision, replacement by a standard primary stem does not induce complications, and the quality of the bone reconstruction allows strong fixation of a regular primary stem.

One-year prospective comparative study of three large-diameter metal-on-metal total hip prostheses: serum metal ion levels and clinical outcomes.

Introduction: The good clinical outcomes and low wear obtained with 28-mm metal-on-metal implants for total hip replacement prompted the development of large-diameter heads that more closely replicated the normal hip anatomy, with the goal of improving prosthesis stability. However, the blood release of metal ions due to wear at the bearing surfaces and the high rate of groin pain seen with large-diameter implants are causing concern. To determine whether these events are related to the geometry and metal composition of the prosthesis components, we conducted a prospective study of clinical outcomes and serum chromium and cobalt levels 1 year after implantation of three different acetabular cups.