| Popis: |
Modular neck components in total hip arthroplasty enhance intraoperative flexibility and ease of revision. Femoral modular components allow alteration of neck length, version, and offset once the femoral stem has been implanted, leading to purported postoperative advantages in reduced wear rate1, enhanced hip stability2,3, increased range of motion, and decreased risk of dislocation3-5. Use of the modular neck also introduces an additional component interface between the neck and the stem, resulting in a large crevice with an angular geometric mismatch between the taper on the modular neck and the sleeve of the proximal femoral neck, which leaves the interface susceptible to micromotion6-10. Over time, micromotion removes the passivation layer on the implants and leads to fretting corrosion, which can be superimposed by crevice corrosion, especially in titanium implants11-13. Retrieval studies have documented the complications of this pathway, including failure to disassemble the neck from the stem14 and implant failure via fracture at the neck-stem interface15-17. This report presents data from a series of patients with the complication of symptomatic hydrogen pneumarthrosis, which, we postulate, may be an early marker of aseptic crevice corrosion and possibly failure of titanium-on-titanium (Ti/Ti) modular neck-stem implants. To the best of our knowledge, this complication has not been previously reported. One case is discussed in detail. All of the patients were informed that data concerning their cases would be submitted for publication, and they provided consent. This case report was approved by our institutional review board. We have collected data on six patients with symptomatic aseptic hydrogen pneumarthrosis following total hip arthroplasty with a Ti/Ti modular neck-stem interface (Table I). To our knowledge, these are the only reports of this complication in … |
