Higher cartilage wear in unipolar than bipolar hemiarthroplasties of the hip at 2 years: A randomized controlled radiostereometric study in 19 fit elderly patients with femoral neck fractures

Abstract

Background and purpose — The use of unipolar hemi­arthroplasties for femoral neck fractures is increasing in some countries due to reports of higher reoperation rates in bipolar prostheses. On the other hand, it has been proposed that bipolar hemiarthroplasties have clinical advantages and less cartilage wear than unipolar hemiarthroplasties. We compared cartilage wear between bipolar and unipolar hemiarthroplasties using radiostereometric analyses (RSA), in patients aged 70 years or older.Patients and methods — 28 ambulatory, lucid patients were randomized to treatment with a unipolar or a bipolar hemiarthroplasty for an acute femoral neck fracture. Migration of the prosthetic head into the acetabulum was measured using RSA. Secondary outcomes were Harris Hip Score (HHS), and EQ-5D scores. Patients were assessed at 3, 12. and 24 months.Results — 19 patients were available for follow-up at 2 years: mean proximal penetration was 0.83 mm in the unipolar group and 0.24 mm in the bipolar group (p = 0.01). Mean total point movement was 1.3 mm in the unipolar group and 0.95 mm in the bipolar group (p = 0.3). Median HHS was 78 (62–96) in the unipolar group and 100 (70–100) in the bipolar group (p = 0.004). Median EQ-5D Index Score was 0.73 (0.52–1.00) in the unipolar group and 1.00 (0.74–1.00) in the bipolar group (p = 0.01). Median EQ-5D VAS was 70 (50–90) in the unipolar group and 89 (70–95) in the bipolar group (p = 0.03)Interpretation — Patients with unipolar hemiarthroplasties had higher proximal cartilage wear and lower functional outcomes. Unipolar hemiarthroplasties should be used with caution in ambulatory, lucid patients.

Meta-analysis of unipolar and bipolar hemiarthroplasty for femoral neck fractures

“…We removed the studies by Sabnis et al and Brenkel et al in the meta-analysis, and the heterogeneity was signi cantly reduced, possibly because the small sample size caused a deviation in the experimental results. There was no statistically signi cant difference in the mortality between the unipolar and bipolar groups, which is consistent with the ndings of many studies [8,10,11,[15][16][17][22][23][24].…”

“…After the removal of duplicated documents (n = 1088), 1472 articles were included. After reading the title and abstract, 39 articles were included for full-text reading, among which, the articles by by Hedbeck [11] in 2011 and Inngul et al [12] in 2013 focused on the same experimental study, with the measurement of the indicators at different time nodes. Therefore, these two articles were included for nal analysis.…”

“…Therefore, these two articles were included for nal analysis. A total of 19 eligible articles [5,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] involving 3149 patients were nally included in this meta-analysis. The basic information and quality of the included studies are shown in Table 1.…”

“…A total of 10 studies reported the mortality rate [8,10,11,[15][16][17][22][23][24], including 1687 cases, of which 990 cases were in the unipolar group and 697 cases in the bipolar group. We analyzed the mortality in the following postoperative periods: less than 6 months, 12 months, and more than 24 months (Fig.…”

Interdisciplinary care of hip fractures.

“…With attention around this, cement-related complications will be reduced to a barely measurable level [49]. A bipolar hemiarthroplasty reduces wear of the acatabulum compared to a unipolar, but a clinical advantage has yet to be unequivocally demonstrated [50]. Total hip arthroplasty is considered for relatively fit patients with femoral neck fractures.…”