Retentive Cup Arthroplasty in Selected Hip Fracture Patients—A Prospective Series With a Minimum 3-Year Follow-Up

OBJECTIVE To evaluate the efficacy of the use of retentive cup primary total hip replacement (THR) in high-dislocation risk subcapital fracture patients. METHODS During the years 2008 to 2012, 354 patients with displaced subcapital fracture were operated at our institute. The patients were selected to undergo primary constrained THR according to the following criteria: (1) a preinjury grade 4 or more on the Functional Independence Measure mobility item "5. Locomotion: walking/wheelchair" and grade 4 is defined as "4. Minimal assistance Requiring incidental hands-on help only" (patient performs >75% of the task) and (2) a disease leading to poor motor control. Exclusion criteria were normal muscular control and known infection of the involved joint. RESULTS Of the 354 patients, 87 fulfilled the inclusion criteria and underwent constrained total hip. Average age was 78 years with a female predominance (73%). Fifteen patients had prior hemiparesis, 19 had Parkinson disease, and 35 had generalized sarcopenia. Eighty-five patients had an uneventful recovery, with an average Hip Disability and Osteoarthritis Outcome Score (HOOS) of 76 ± 7 at 2 years. In 2 patients, the prostheses dislocated. In both cases, the dislocation was due to ring displacement and the inner head dislocated. One case was infected and the patient was treated by a Girdlestone procedure. In the other case, the prosthetic head was revised. The patient remained asymptomatic and at 4-year follow-up had an HOOS of 85. DISCUSSION It appears that constrained prosthesis is a suitable treatment for patients with poor muscular control having subcapital fractures. The functional results appear to be superior to those of bipolar arthroplasty and similar to the results of primary total hip arthroplasty while the dislocation risk is <3%. CONCLUSION Semielective total hip arthroplasty using a retentive cup liner appears to offer good functional results with a low dislocation rate in patients with poor muscular control.