Patients undergoing primary total hip arthroplasty (THA) with prior lumbar spine fusion (LSF) are at high risk for instability with reported incidence of dislocation as high as 8.3%. The use of dual mobility cups in patients undergoing revision THA, another high risk group, has demonstrated decreased incidence of instability. Purpose of this study was to evaluate the risk of instability in patients undergoing primary THA with a history of prior LSF using dual mobility cups. This was a multi-center retrospective study with 93 patients undergoing primary THA using a dual mobility cup with prior history of instrumented LSF. The primary outcome investigated was instability. Secondary variables investigated included number of levels fused, approach, length of stay, and other complications. The minimum follow-up time was 1 year since the majority of dislocations occur during first year following the primary THA.Introduction
Methods
Polyethylene wear is the main factor leading to periprosthetic osteolysis, aseptic loosening and long-term failure of the implant in total hip arthroplasty (THA). The present study compares the clinical and radiographic outcomes of 88 patients who underwent primary THA with either conventional polyethylene or cross-linked polyethylene (XLPE) from the same manufacturer (Zimmer®, Warsaw, IN, USA). There were no significant differences between the two sub-populations in average age, gender, side affected and prosthetic stem and cup size. The average follow-up was 104 months, ranging from 55 to 131 months: to our knowledge this is the longest follow-up for this particular insert. Clinical and x-ray evaluation was obtained at 1, 3, 6 and 12 months and yearly thereafter. Our results showed that cross-linked polyethylene has a significantly greater wear reduction than that of standard polyethylene.
