Surgical Approach and Dislocation Risk After Hemiarthroplasty in Geriatric Patients With Femoral Neck Fracture With and Without Cognitive Impairments-Does Cognitive Impairment Influence Dislocation Risk?

Objectives: To determine whether there is an association between surgical approach and dislocation risk in patients with cognitive impairment compared with those without cognitive impairment treated with hemiarthroplasty for femoral neck fracture.

Design: Retrospective study.

Setting: Large, multicenter health system.

Patients/participants: One thousand four hundred eighty-one patients who underwent hemiarthroplasty for femoral neck fractures. 828 hips met inclusion criteria, 290 (35.0%) were cognitively impaired, and 538 (65.0%) were cognitively intact.

Intervention: Hemiarthroplasty.

Main Outcome Measure: Prosthetic hip dislocation.

Results: The overall dislocation rate was 2.1% (17 of 828), 3.4% (10 of 290) in the cognitively impaired group, and 1.3% (7 of 538) in the cognitively intact group with a median time to dislocation of 20.5 days (range 2-326 days), 24.5 days (range 3-326 days), and 19.0 days (range 2-36 days), respectively. In the entire cohort, there were no dislocations (0 of 58) with the direct anterior approach (DA); 1.1% (6 of 553) and 5.1% (11 of 217) dislocated with the modified Hardinge (MH) and posterior approaches (PA), respectively. In the cognitively impaired group, there were no dislocations with the DA (0 of 19); 1.5% (3 of 202) and 10.1% (7 of 69) dislocated with the MH and PA, respectively. In the cognitively intact group, there were no dislocations (0 of 39) with the DA; 0.85% (3 of 351) and 2.7% (4 of 148) dislocated with the MH and PA, respectively. There were statistically significant associations between surgical approach and dislocation in the entire cohort and the cognitively impaired group when comparing the MH and PA groups. This was not observed in the cognitively intact group. Patients who dislocated had 3.2 times (95% CI 1.2, 8.7) ( P = 0.0226) the hazard of death compared with patients who did not dislocate. Dislocation effectively increased the risk of death by 221% (HR 3.2 95% CI 1.2, 8.7) ( P = 0.0226).

Conclusions: In this patient population, the PA has a higher dislocation rate than other approaches and has an especially high rate of dislocation when the patients were cognitively impaired. The authors of this study suggest careful consideration of surgical approach when treating these injuries.

Level Of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.