We undertook a randomised controlled trial to compare bipolar hemiarthroplasty (HA) with a novel total hip replacement (THR) comprising a polycarbonate–urethane (PCU) acetabular component coupled with a large-diameter metal femoral head for the treatment of displaced fractures of the femoral neck in elderly patients. Functional outcome, assessed with the Harris hip score (HHS) at three months and then annually after surgery, was the primary endpoint. Rates of revision and complication were secondary endpoints.

Based on a power analysis, 96 consecutive patients aged > 70 years were randomised to receive either HA (49) or a PCU-THR (47). The mean follow-up was 30.1 months (23 to 50) and 28.6 months (22 to 52) for the HA and the PCU group, respectively.

The HHS showed no statistically significant difference between the groups at every follow-up. Higher pain was recorded in the PCU group at one and two years’ follow-up (p = 0.006 and p = 0.019, respectively). In the HA group no revision was performed. In the PCU-THR group six patients underwent revision and one patient is currently awaiting re-operation. The three-year survival rate of the PCU-THR group was 0.841 (95% confidence interval 0.680 to 0.926).

Based on our findings we do not recommend the use of the PCU acetabular component as part of the treatment of patients with fractures of the femoral neck.

Cite this article: Bone Joint J 2013;95-B:609–15.

Introduction

In elderly patients, the incidence of a second fracture in the contralateral hip within 2 years of a femoral neck fracture (FNF), ranges from 7 to 12%.

Knowing patient bone density is important to select the proper fixation technique and for secondary osteoporosis medical treatment. However few studies addressing hip fractures provided data regarding patient bone mineral density.

Materials and Methods: Four hundred and thirty three consecutive female patients were included in our study. Inclusion criteria were: AO/OTA fracture type A1, A2 or B, age ? 80 years and minor trauma. BMD values of the lumbar spine (L2–L4) and right proximal femur (neck, trochanter, Ward’s triangle) were measured by dual-energy x-ray absorptiometry. Patients were divided into three groups: Group A had trochanteric fractures (n = 79, average age 85 ? 5), Group B had femoral neck fractures (n = 67, age 84 ? 4) and Group C had no fractures (n = 287, age 82 ? 2). Data was assessed statistically using Analysis of Variance (ANOVA) and receiver operating characteristic (ROC) analysis.

Results: Group A ROC curve had higher values when compared to Group B ROC curve in all corresponding BMD tested sites. Total number of patients with femoral neck fracture and a T-score higher then −2.5 SD were 14 (20.9%), 25 (37.3%) and 16 (23.9%) at the femoral neck, trochanter and at the Ward’s triangle respectively. Patients with a trochanteric fracture and a T-score higher than −2.5 SD were 8 (10.1%), 15 (19.0%) and 12 (15.2%) at the femoral neck, trochanter and Ward’s triangle respectively. BMD values at the trochanteric measurement site demonstrated that the incident rate between the two patient groups differed significantly depending on the diagnosis of osteoporosis (Chi square test: X² = 6.12, p = 0.013).

Discussion: There are notable differences in bone mass density. Femoral neck BMD proved to be the best diagnostic site using DXA, with 15.07% of hip fracture patients having a normal age-related bone mass. Higher non-osteoporotic bone densities were found in women with hip fractures: BMD values were (27.40%) at the trochanter and (17.81%) at the Ward’s triangle.

Conclusions: There was a significant difference between non-osteoporotic related fractures in Group A and Group B. There were more non-osteoporotic related fractures in Group B. A lower BMD was found in patients with trochanteric fractures than in patients with femoral neck fractures. Assessment of bone quality in these patients is of paramount importance in choosing the correct surgical treatment. In patients with poor bone quality, fixation augmentation techniques can be used. We recommend routine DXA scans of the affected fractured hip in all elderly hip fracture patients prior to surgery.