Does an Extended Offset Stem Improve Hip Stability and Function in Elderly Patients with a Femoral Neck Fracture?

BACKGROUND

Hip fractures in elderly patients remain a major clinical challenge, with optimal surgical strategies still debated. Evidence regarding abductor strength recovery and functional outcomes after total hip replacement (THR) using an extended offset cemented stem in elderly patients with femoral neck fracture (FNF) remains limited. We evaluated functional outcomes and abductor muscle strength of THR for FNF in elderly patients, comparing an extended medial offset (MO) stem and a standard MO stem.

METHODS

We retrospectively reviewed 120 patients undergoing THR with an extended MO Exeter 44-mm stem (group A) and 100 patients undergoing THR with a standard MO Exeter 37.5-mm stem (group B) for FNF. We enrolled patients with a Koval grade of 3 or higher, an American Society of Anesthesiologists (ASA) grade of 3 or lower, and a Mini-Mental State Examination score of 24 or higher. Postoperative MO of the affected hip was compared with the native hip. Abductor muscle strength was measured using a muscle dynamometer (KINVENT technologies). Complications including dislocation, thigh pain, and greater trochanteric pain (GTP) were investigated.

RESULTS

No significant differences in ASA, body mass index, bone mineral density, or implant position were observed between the 2 groups. The mean MO of the affected hip was 42.6 mm in group A and 36.2 mm in group B, approximately 5 mm greater than the native hip in group A (37.8 mm) and 6 mm greater in group B (30.4 mm). Abductor muscle power of the affected hip recovered to approximately 86% of the native hip in group A and 81% in group B. No dislocations or thigh pain occurred. In group A, 5 patients had mild GTP treated with physical therapy. Group A demonstrated smaller differences between the affected and native hips in mean MO, mean vertical offset, and abductor muscle strength compared with group B (p < 0.05).

CONCLUSIONS

For healthy elderly patients with FNF undergoing THR, the extended MO stem had a positive effect on the recovery of abductor muscle strength, potentially contributing to improved joint stability.