Arthroplasty in patients with femoral neck fractures

The aim of this thesis was to analyze hip function and the health-related quality of life (HRQoL) in patients with a displaced fracture of the femoral neck treated with a cemented total hip arthroplasty (THA) or a hemiarthroplasty (HA), unipolar or bipolar. Moreover, the purpose was to analyze factors influencing the stability of the THA with special reference to the surgical approach and to evaluate the responsiveness of the Short Musculoskeletal Function Assessment (SMFA), i.e. the instrument’s ability to capture clinically important changes, in patients with femoral neck fractures.

A four-year follow-up of a randomized controlled trial (RCT) of 120 elderly patients (mean age 81 years) with a displaced femoral neck fracture randomly allocated to treatment by either THA or bipolar HA (Study I). The results confirmed the better outcome regarding hip function and HRQoL after THA as compared to HA in the longer time perspective. In an RCT, 120 elderly patients (mean age 86 years) with a displaced fracture of the femoral neck were randomly allocated to treatment by either unipolar HA or bipolar HA (Study II). The study showed that unipolar HA and bipolar HA appeared to produce equivalent clinical outcomes regarding hip function and HRQoL after one year, but with a significantly higher incidence of acetabular erosion in the unipolar HA group. In a cohort study, 713 consecutive hips in a series of 698 patients having undergone a primary THA (n = 311) for a displaced femoral neck fracture or a secondary THA (n = 402) due to a fracture healing complication after a femoral neck fracture were included (Study III). The results showed that the anterolateral surgical approach was associated with a significantly lower risk of dislocation than the posterolateral approach with or without posterior repair.

In order to evaluate the responsiveness of the SMFA, the 120 patients from Study I were included (Study IV). To evaluate the internal responsiveness of the SMFA, the observed change and the Standardized Response Mean (SRM) in relation to the change in the Dysfunction Index and the Bother Index were calculated. In order to calculate external responsiveness, an External Criterion (EC) was constructed by using the Harris Hip Score. Receiver Operating Characteristic (ROC) curves and logistic regression analysis were used in the evaluation. The results of the study showed that the SMFA indices had good internal responsiveness and acceptable external responsiveness in patients with femoral neck fractures.

In conclusion, THA is recommended as the primary treatment for the active, healthy elderly patient with a femoral neck fracture and long life expectancy. In the most elderly patients, bipolar HA and unipolar HA seem to produce equally good clinical results in the shorter time perspective, but the significantly higher incidence of acetabular erosion in the unipolar HA group may imply that bipolar HA should be the preferred treatment. Moreover, in order to minimize the risk of dislocation, we recommend the use of the anterolateral approach for THA in patients with femoral neck fractures. Finally, the SMFA can be recommended for use as one of the measures to evaluate the outcome after a femoral neck fracture.

List of scientific papers

I. Comparison of bipolar hemiarthroplasty with total hip arthroplasty for displaced femoral neck fractures. A concise four-year follow-up of a randomized controlled trial. Hedbeck CJ, Enocson A, Lapidus G, Blomfeldt R, Törnqvist H, Ponzer S, Tidermark J. Journal of Bone and Joint Surgery (Am). 2011 Mar; 93(5): 445-50.
https://doi.org/10.2106/JBJSJ.00474

II. Unipolar hemiarthroplasty versus bipolar hemiarthroplasty in the most elderly patients with displaced femoral neck fractures: a randomised, controlled trial. Hedbeck CJ, Blomfeldt R, Lapidus G, Törnqvist H, Ponzer S, Tidermark J. Int Orthop. 2011 Feb 8.
https://doi.org/10.1007/s00264-011-1213-y

III. Dislocation of total hip replacement in patients with fractures of the femoral neck. A prospective cohort study on 713 consecutive hips. Enocson A, Hedbeck CJ, Tidermark J, Pettersson H, Ponzer S, Lapidus L. Acta Orthopaedica. 2009 Apr; 80(2): 184-9.
https://doi.org/10.3109/17453670902930024

IV. Responsiveness of the Short Musculoskeletal Function Assessment (SMFA) in elderly patients with femoral neck fractures. Hedbeck CJ, Tidermark J, Ponzer S, Blomfeldt R, Bergström G. Quality of Life Research. 2011 May; 20(4): 513-21.
https://doi.org/10.1007/s11136-010-9784-4