Is the dislocation rate higher after bipolar hemiarthroplasty in patients with neuromuscular diseases?
BACKGROUND
Patients with neuromuscular disease reportedly have a higher incidence of postoperative dislocation after bipolar hemiarthroplasty. Although the literature has focused on a high prevalence of preoperative neurologic conditions in patients who had dislocations after bipolar hemiarthroplasties, the relative incidence of dislocation in patients with neuromuscular disease and without is unclear.


OBJECTIVE
We therefore (1) asked whether the incidence of postoperative dislocation after bipolar hemiarthroplasty was greater in patients with neuromuscular disease than for those without, and (2) whether function differed between the two groups, and (3) explored potential risk factors for dislocation in two groups.


METHODS
We retrospectively reviewed 190 patients who underwent bipolar hemiarthroplasties for fracture of the femoral neck between 1996 and 2008. Of the 190 patients, 42 had various neuromuscular diseases and 148 had no history of neuromuscular disease. Intraoperative stability was tested and posterior soft tissue repair was performed in all patients. We determined the incidence of dislocation, postoperative leg length discrepancy, and femoral offset in patients with or without neuromuscular disease.


RESULTS
The incidence of dislocation was 2.6% in all patients. We observed similar rates of dislocation in the two groups: 4.8% (two of 42 hips) in patients with neuromuscular disease and 2.0% (three of 148 hips) in patients without neuromuscular disease.


CONCLUSIONS
In femoral neck fractures in patients with neuromuscular disease, careful preoperative management and operative technique such as a posterior soft tissue repair might decrease the risk of postoperative dislocation; therefore, we consider the bipolar hemiarthroplasty a reasonable treatment option.


METHODS
Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Department of Orthopaedic Surgery, Pusan National University School of Medicine, Beomeo-ri, Mulgeum-eup, Yangsan 626-770, Korea. kuentak@pusan.ac.kr
Kuen Tak
KT
Suh
Dae Woong
DW
Kim
Hong Seok
HS
Lee
Yoon Jae
YJ
Seong
Jung Sub
JS
Lee
D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D006617:Hip Dislocation / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D004204:Joint Dislocations / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009468:Neuromuscular Diseases / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors