Radiological Riskfactors for Dislocation of Hip Hemiarthroplasty (RRDHHR)

Between January 1 2006 and December 31 2013, at our department 324 patients underwent hemiarthroplasty (HA) for displaced femoral-neck fracture with a bipolar prosthesis (Variokopf, Link®, Germany) by the use of the posteriolateral approach. Patients with pathological fractures and HA performed with direct lateral approach were excluded. A retrospective cohort study were conducted. Patients with prosthetic dislocation formed one group and patients without dislocation formed the control group.

As standard, post surgery radiographs (anteroposterior and lateral) were taken. After these were performed patient started weight bearing as soon as possible. Clinical data regarding patient demographics, details of the surgical procedure and the medical comorbidities were collected by the use of patient and operative records. Radiological analysis with position evaluation was performed using the post surgery radiographs by measuring Wiberg angle, inequality of leg length and femoral offset of the prostheses and compared with non-operated hip joint using the post surgery x-ray images.

Our hypothesis were that patients with single- or recurrent dislocations had shortened postoperative leg length, decreased femoral offsed and a Wiberg angle less than 25 degrees.