Afshin Taheri azam - Orthopedic Hip Surgeon, Department of Orthopedics Surgery, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
Rarshad Safdari - Bone, Joint and Related Tissues Research Center, Shahid Beheshti University of medical sciences

BackgroundsInstability following total hip arthroplasty (THA) is a serious disabling complication.Even revision THA due to the recurrent dislocation can be associated with persistentinstability. Dual mobility implants (tripolar prosthesis) are used to reduce the riskof recurrent hip dislocation. However, there is little knowledge about the mid-termand long-term outcomes of using these implants. In current study, we evaluated themidterm results of treating recurrent THA dislocation using tripolar prosthesesMethodsBetween 2005 and 24 ,2011 consecutive patients were revised due to recurrenthip dislocation. The patients aged 10.6±62.4 years at the time of surgery. All of thepatients had at least 2 episodes of dislocation. Preoperative Harris hip score (HHS) was11.5±46.1. Patients were followed for 4.1±6.2 years.ResultsAt the last visit, HHS improved significantly (12.6±83.5, p<0.001). Redislocationoccurred in one patient who required a more revision surgery (%4.1). No patientdeveloped infection and or symptomatic deep venous thrombosis. Also, we found nopatient with implant loosening or periprosthetic fracture.ConclusionsTripolar hip prostheses are useful and effective for treatment of patients with recurrenthip instability after THA. However, more large long-lasting prospective studies are required.