Modular stem hip system yields low survivorship after THA
Using a modular stem hip system for primary total hip arthroplasty procedures resulted in a low survivorship rate at a minimum of 5 years, according to a recent study.
Investigators evaluated survivorship of the ALFA II modular hip system (Encore Medical/DJO Surgical) among 221 patients who underwent a primary THA with a minimum 5-year follow-up. Twenty-eight patients died of causes unrelated to the surgery before adequate follow-up and 64 patients were lost to follow-up, leaving 129 patients with a mean 6.5-year follow-up.
After the mean 6.5-year follow-up, the modular stem system had an all-cause survivorship rate of 81%. Revision surgery was required by 19.4% of patients; 52% for dissociation of the modular components, 32% for fracture of the prosthesis, 12% for instability/multiple dislocations and 4% for chronic septic THA. BMI and offset were independent risk factors for mechanical failures of the modular stem system.
“The relatively higher number of failures may be because of the increased risk of fretting and corrosion that comes along with modularity at a high stress location and may also be associated with the shape of the femoral taper,” the researchers wrote. “We caution the routine use of primary THA systems featuring modularity at the neck/body junction similar to this design.” – by Casey Tingle
Disclosures: Nahhas reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.