Dual mobility cup in hip fracture: Indications and clinical results compared with bipolar hip arthroplasty.

Introduction: The choice between hemiarthroplasty (HA) and total hip arthroplasty (THA) for displaced femoral neck fractures remains debated. There is increasing use in dual mobility cup total hip arthroplasty (DMC-THA) to prevent dislocations in these high-risk patients. Aim of this study is to retrospectively analyze patients treated in a single Center for femoral neck fracture comparing HA and DMC-THA in terms of: functional outcome, rate of complications and mortality.

Material and methods: Between 2020 and 2022, 162 patients were included, 39 male and 123 female, with a mean age of 76 years old. HA were implanted in 82 cases and DMC-THA in 80 cases. INCLUSION CRITERIA WERE: age < 85 years old, American Society of Anesthesiologists (ASA) score below 3, minimum follow-up of 6 months. Overall, 124/162 of patients (77%) were surgically treated within 48 h from admission.

Results: The mean age for DMC-THA group was 74 years old and 78 years old for HA group. The overall mean surgical time was significantly higher in the DMC-THA group (P < 0.001). Mean hemoglobin (Hb) loss was 1.64 g/dl in the HA group and 1.72 g/dl in the DMC-THA group with no differences between the two groups (P = 0.573). There is no difference in survival of patients between the two groups (P = 0.7704). In the HA group, the mean one-month post-operative VAS score was 2.1, while in the DMC-THA group was 0.9. The Harris hip score was significantly better in DMC-THA group (P = 0.035) Dislocation never occured in the overall series. Infection occurred only in one patient with DMC-THA and was treated with debridement. Periprosthetic fracture occurred in 2 cases of DMC-THA both within 1 month from the first surgery; one was treated with revision femoral stem and the second one with fixation.

Conclusions: DMC-THA offer better functional results than HA in elderly patients with femur neck fractures. The mean surgical time was longer in DMC-THA but this did not influence blood loss, time of discharge or one-year mortality. In our series dislocation never occurred in both groups.