Cemented versus uncemented hemiarthroplasty for displaced femoral neck fractures: 5-year followup of a randomized trial

Abstract

Background: Displaced femoral neck fractures usually are treated with hemiarthroplasty. However, the degree to which the design of the implant used (cemented or uncemented) affects the outcome is not known and may be therapeutically important.

Questions/purposes: In this randomized controlled trial, we sought to compare cemented with cementless fixation in bipolar hemiarthroplasties at 5 years in terms of (1) Harris hip scores; (2) femoral fractures; (3) overall health outcomes using the Barthel Index and EQ-5D scores; and (4) complications, reoperations, and mortality since our earlier report on this cohort at 1-year followup.

Methods: We present followup at a median of 5 years after surgery (range, 56-65 months) from a randomized trial comparing a cemented hemiarthroplasty (112 hips) with an uncemented, hydroxyapatite-coated hemiarthroplasty (108 hips), both with a bipolar head. Results were previously reported at 1-year followup. Harris hip scores, Barthel Index, and EQ-5D scores were assessed by one research nurse and one orthopaedic surgeon. Complications and reoperations were determined by chart review and radiographs examined by three orthopaedic surgeons. Sixty patients (56%) had died in the cemented group and 63 (60%) in the uncemented group. Respectively, three and two patients (2.7% and 1.9%) were completely lost to followup.

Results: Harris hip scores at 5 years were higher in the uncemented group than in the cemented group (86.2 versus 76.3; mean difference 9.9; 95% confidence interval [CI], 1.9-17.9). The prevalence of postoperative periprosthetic femoral fractures was 7.4% in the uncemented group and 0.9% in the cemented group (hazard ratio [HR], 9.3; 95% CI, 1.16-74.5). Barthel Index and EQ-5D scores were not different between the groups. Between 1 and 5 years, we found no additional infections or dislocations. The mortality rate was not different between the groups (HR, 1.2; 95% CI, 0.82-1.7).

Conclusions: Both arthroplasties may be used with good medium-term results after displaced femoral neck fractures. The uncemented hemiarthroplasty may result in higher hip scores but appears to carry an unacceptably high risk of later femoral fractures.

Level of evidence: Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

The diagram shows the recruitment and flow of femoral neck fractures during the study.

Fig. 2

A series of radiographs shows the Spectron cemented bipolar hemiarthroplasty at four time intervals.

Fig. 3

A series of radiographs shows the Corail uncemented bipolar hemiarthroplasty at four time intervals.

Fig. 4

The graph shows the mean difference of Harris hip score between the two groups at 3 and 12 months. Error bars indicate 95% CIs. Tinted area indicates zone of equivalence, defined as ± 10 points (Δ). At 3 months and at 1 year, both CIs lie wholly inside of the zone of equivalence and include zero. This shows that the results in the uncemented group were equivalent but not superior to the cemented group. At 5 years, the CI lies wholly above zero, showing that the results in the uncemented group were superior to the cemented group.

Fig. 5

The survival curve with 95% CIs shows the cemented and uncemented hemiarthroplasties with postoperative periprosthetic femoral fracture as the endpoint, censored for death.

Fig. 6

The survival curve with 95% CIs shows the patients with cemented and uncemented hemiarthroplasties with death as the end point. Seven patients were included with both hips and are only included with their first hip in the mortality analysis.