Implant Movement Analysis in theroutine diagnosis of aseptic looseningafter hip arthroplasty, a two year followup

Introduction: A major long-term complication after hip arthroplasty is aseptic loosening.Conventional planar radiographs cannot always provide a certain diagnosis, which makesdecisions regarding revision surgery difficult. Implant Movement Analysis (IMA) is a newlyintroduced method which uses computer tomography with inward and outward rotationalprovocation to display possible movement of the hip implant. Aim: To evaluate IMA as a complement to planar radiography and follow up on patientswhere IMA has showed no loosening of the implant. How accurate are the results that IMAhas provided in a two to four year follow up? Methods: Letters with questions regarding how they felt in their hip were sent out to hiparthroplasty patients (n= 49) that had been examined by IMA and were told that theirprosthesis was not lose. Patients that said they were experiencing more pain in their hip wereasked to come in for a follow up with planar radiography. The new planar radiographs werecompared with the previous ones deemed not lose by IMA as the reference. Results: A total of 42 patients answered. For 10 patients the pain had improved, 15 felt nodifference, and for 17 the pain had worsened. For the patients that felt worse, planarradiography had changed for two of them indicating loosening of the implant. Conclusions: IMA has shown to accurate in diagnosing aseptic loosening where the planarradiographs were not able to provide a diagnosis. But as a new method additional evaluationis desired