Posterior versus lateral approach for hemiarthroplasty after femoral neck fracture: Early complications in a prospective cohort of 583 patients.

AIM: To compare early complications after the posterior and the direct lateral (transgluteal) approach, when using hemiarthroplasty in the treatment of displaced femoral neck fractures in the elderly.

PATIENTS AND METHODS: A prospective clinical study from four Norwegian hospitals, consisting of 583 patients with 1year follow-up. All the hospitals used the same uncemented femoral stem and bipolar heads. Data were collected for gender, age, surgical approach, prosthetic dislocation, postoperative infection, perioperative fracture, duration of surgery, ASA score, diabetes, alcoholism, cognitive failure, BMI, 30-day mortality and 1-year mortality.

RESULTS: Mean age was 83 years (SD 7.8) and 434/583 (74%) were female. There were no relevant differences between the treatment groups. A higher risk was found for prosthetic dislocation in the posterior group compared to the lateral group (15/186 (8%) vs. 4/397 (1%); RR=8.0, 95% CI 2.7-23.8, p-value<0.001), both as a one-time event and for the risk of recurrent dislocations (9/186 (5%) vs. 2/395 (0.5%); RR 9.6, 95% CI 2.1-44.0, p-value=0.001). 11/19 patients with dislocation had recurrent dislocations. 10/11 patients with more than one dislocation needed further open surgery. Of those 6/10 needed more than one additional open procedure. Three patients had a resection arthroplasty and one patient had a chronic infection as final result after a dislocation. No other risk factor for dislocation than surgical approach was identified. There were no differences between the approach groups for other complications.

CONCLUSION: There was an 8-fold increased risk for prosthetic dislocations after the posterior approach compared to lateral approach. There was a high risk for recurrent prosthetic dislocations and a subsequent risk for further surgeries and a poor end result. The potential advantages of the posterior approach have not been demonstrated after femoral neck fractures and we advise against its continued use.