Comparison of Unipolar (Moore’s Prosthesis) and Bipolar Hemiarthroplasty in Fracture Neck of Femur in the Elderly- A Short-Term Prospective Study

Abstract

BACKGROUND Femoral neck fractures are common in postmenopausal elderly females as a result of osteoporosis due to trivial trauma or in the young due to high energy trauma. The goal of the surgeon is to return the patient to his/her prefracture functional status. Femoral neck fracture could be impacted and undisplaced or displaced. Femoral neck fractures are also considered "fractures of necessity", best treated surgically irrespective of displacement. Surgery permits early patient mobilisation and minimises the complications of prolonged recumbence. The bipolar prosthesis has advantage over the unipolar in having two bearings for the movements to occur. This study intends to compare the functional outcome of unipolar Moore's hemi-replacement and fixed bipolar replacement in elderly patients with fracture neck of femur. In this scenario, the null hypothesis would be that there is no significant difference in the results between the patients treated with Moore's prosthesis and those treated with bipolar prosthesis. The aim of the study is to compare the results of unipolar and bipolar hemi-arthroplasty for fracture neck of femur in the elderly patients. MATERIALS AND METHODS 30 elderly postmenopausal women with fracture neck femur were included in the study. They were divided into 2 groups and were operated upon by using unipolar and bipolar implants respectively after thorough investigation. The functional outcome was assessed using the Harris Hip Score (HHS). RESULTS Femoral neck fractures belonged to 53.3% with type III fracture and 46.7 had type IV fractures. Fifteen patients had replacement with Austin Moore prosthesis and fifteen patients with bipolar prosthesis. The average HHS at 6 weeks for unipolar and bipolar groups was 65.2 and 66.0, respectively. The average HHS at 12 months for unipolar and bipolar group was 81.0 and 83.6, respectively. 19 (65.5%) patients had good HHS at the end of one year. Corrected chi-square value is 2.84, df 2 and p value is 0.241, which is >0.05 showing no significance. CONCLUSIONS There was no difference in functional outcomes in different age groups in both unipolar and bipolar groups. Females were involved overall more commonly than males, but there was no significant difference in final functional outcome in two groups. No advantage was found for the bipolar prosthesis over the unipolar prosthesis. No difference in functional outcome, return to pre-injury status, patient satisfaction or hip score in both groups.