Dislocations after hip hemiarthroplasty for acute femoral neck fractures: a scoping review.

BACKGROUND: Dislocation of a hip hemiarthroplasty is a common complication; however, the literature is mixed regarding dislocation rates and risk factors. There is a need for a comprehensive review of all potential risk factors to potentially tailor surgical techniques that reduce the risk of dislocation.

OBJECTIVE: The objective is to provide an overview of studies reporting on dislocation in patients with femoral neck fractures, with an emphasis on rates, risk factors, and patient-reported outcomes following dislocation.

METHODS: This scoping review was conducted in accordance with the methodology of the Joanna Briggs Institute for scoping reviews. We developed a search strategy for Embase, MEDLINE, PubMed, and the Cochrane Library. Papers describing dislocation rates, risk factors, or patient-reported outcomes were included. All identified citations were assessed in Covidence by two independent reviewers. The following quality assessment elements were considered: single- or multi-centre studies, follow-up time, and changes over time, with a minimum of five studies involving at least 10 patients.

RESULTS: There were 178 papers meeting the inclusion criteria, with over 900.000 participants analysed. The reported dislocation rate ranged from 0% to 16.6%. The randomised controlled trials reported a median dislocation rate of 2.1%, with similar rates in other study designs. Single- and multi-centre studies had a median dislocation rate of 2.3%. Follow-up studies of ≤ 6 months had a median dislocation rate of 2.3%, which increased to 2.9% after ≥ 2 years. Publications after 2020 showed a median dislocation rate of 2.0% compared to 6.3% in publications before 1990. Forty-eight studies identified the following risk factors: cognitive impairment, a smaller centre-edge angle (CEA), a smaller or larger offset or acetabulum, and a posterior approach. Patient-reported outcomes or experiences after a hemiarthroplasty dislocation were not included in any study.

CONCLUSION: The dislocation rate among patients with hip hemiarthroplasties following femoral neck fractures varied considerably in the literature. This review suggests that the posterior approach should be avoided to prevent dislocation in patients, particularly those with cognitive impairment, and to consider the patient's acetabular size. There is a lack of research on patient-reported outcomes after hip hemiarthroplasty dislocation, which warrants further investigation.