Clinical Outcomes of Bipolar Hemiarthroplasty with a Conjoined Tendon-Preserving Posterior Approach for Femoral Neck Fractures

Abstract

Background and Objectives: The conventional posterior approach in the lateral decubitus position is widely used for femoral neck fractures in femoral hemiarthroplasty. Postoperative dislocation is the major problem with this approach. The conjoined tendon-preserving posterior (CPP) approach is a less invasive surgical approach than the conventional posterior approach to the hip, maintains posterior stability, and preserves short external rotators and joint capsules. However, the mention was required to avoid muscle damage and whether muscle damage affects postoperative dislocation or not. The current study aimed to evaluate the clinical results of the CPP approach in hemiarthroplasty for femoral neck fractures and identify muscle damage risk factors. Materials and Methods: This study was a retrospective cohort study and included 170 hips in 168 patients. The mean age at the operation was 81.2 years. The preservation rate of the internal obturator muscle and gemellus inferior muscle and factors related to intraoperative short rotator muscle injury were investigated retrospectively. The postoperative complications and the relation between muscle damage and postoperative dislocation were investigated. Results: In the four hips (2.3%) with the obturator internus muscle damage, thirty-eight hips (22.4%) with gemellus inferior muscle damage were detected; in the muscle-damaged cases, the high body mass index (BMI) was significantly higher. The complication occurred in four hips (2.3%), including postoperative posterior dislocation in one hip without muscle damage (0.6%). Postoperative infection occurred in one hip (0.6%), and peroneal or sciatic nerve paralysis was suspected in two hips (1.1%). Conclusions: Compared to the conventional posterior approach in previous reports, the CPP approach reduces postoperative dislocation. A higher BMI is a risk factor for muscle damage, and the gemellus inferior muscle damage has no effect on postoperative dislocation. The CPP approach for BHA appeared to be an effective treatment method.

Keywords: bipolar hemiarthroplasty; body mass index; complication; conjoined tendon-preserving posterior; elderly person; femoral neck fracture; postoperative dislocation.

Figure 1

Exposed short eternal rotators. The black indicates the L-shaped resection line of the CPP approach. P: piriformis tendon.; GS: gemellus superior muscle; IO: internal obturator muscle; GI: gemellus inferior muscle; EO: external obturator muscle; Q: quadratus femoris muscle; CPP: conjoined tendon-preserving posterior.

Figure 2

The femoral head was removed from the acetabulum using two elevators. IO: internal obturator muscle; GI: gemellus inferior muscle; EO: external obturator muscle; Q: quad-ratus femoris muscle.

Figure 3

Femoral broaching is performed carefully so as not to damage the short external rotators. GS: gemellus superior muscle; IO: internal obturator muscle; GI: gemellus inferior muscle.

Figure 4

Kaplan–Meier survivorship analysis was 94.6% (95% CI 88.2–97.1) at 12 months after surgery, with deaths not related to fractures as the endpoint.