Hip hemiprosthesis due to femoral neck fracture in the elderly population - are we doing it right?

Abstract

Introduction: Femoral neck fracture is one of the most common orthopaedic traumas affecting the elderly population. The standard treatment method is hip hemiarthroplasty and total hip arthroplasty. In hip hemiprostheses surgeons mainly have to reconstruct the femoral offset and limbs' length to obtain the correct gait biomechanics and a satisfactory surgical outcome.The aim of this study is to examine the radiological results of patients after hip hemiarthroplasty for femoral neck fracture and to evaluate the reconstruction of the femoral offset using standard neck angle stems.

Material and methods: A consecutive series of 97 patients diagnosed with femoral neck fracture treated with a hip hemiprosthesis between 2017 and 2021 was identified and met the inclusion criteria. On preoperative images, the neck-shaft angle and the femoral offset on the healthy limb were measured. The femoral offset of the operated limb was measured on the postoperative X-rays.

Results: There was a significant positive moderate correlation between neck-shaft angle and femoral offset change (r = 0.568, p < 0.0001). There was a statistically significant difference between femoral offset change and neck-shaft angle (24:52 vs. 14:7, p = 0.005). This means that in patients with coxa vara the change in femoral offset was more often < -5 mm. Less than half of operated patients had the femoral offset restored within a safe range (between -5 and 5 mm).

Conclusions: Our study proved that it is sometimes hard to achieve femoral offset within a safe range while performing hip hemiarthroplasty in patients with coxa vara. The topic of using high offset stems in partial hip arthroplasty has not been thoroughly researched worldwide. However, taking into account the results of our study, during a hip hemiarthroplasty the usage of high offset stems for varus hips should be considered in order to improve the clinical outcome and improve patients' quality of life and functioning.

Keywords: femoral offset; hip hemiprosthesis; neck-shaft angle; radiographic evaluation.