Comparative study of total hip arthroplasties with dual mobility cups versus hemiarthroplasties in management of femoral neck fractures: Survival and dislocation rate at 5 years of follow-up?

The use of uncemented stems in femoral neck fractures in elderly patients: A comparative study of 671 cases

INTRODUCTION

The use of cemented stems in elderly patients is associated with the risk of intraoperative embolic complications. Uncemented stems eliminate this risk, but their use is controversial because of the risk of mechanical complications, with estimated subsidence between 3.6 and 30% and periprosthetic fractures between 2.1 and 11% at 6 weeks. A retrospective multicenter comparative study was conducted using a propensity score analysis to evaluate mechanical performances of uncemented stems in femoral neck fractures in elderly patients to (1) compare the risk of mechanical complications and (2) assess the use of metaphyseal-anchored stems for this indication.

HYPOTHESIS

There is no difference in the risk of mechanical complications, intraoperatively or postoperatively, between these stems.

MATERIALS AND METHODS

We conducted a multicenter retrospective comparative study including 358 uncemented and 313 cemented stems. The mean age was 84.5 years [83.9-85.1]. The inclusion criteria were patients 70 years and older and a follow-up of at least 6 weeks. The primary endpoint was a composite endpoint comprised of stem subsidence≥2mm or periprosthetic fracture (up to 3 months postoperatively). The secondary endpoints were infection, stem subsidence≥2mm, and operative time. These endpoints were analyzed using a propensity score to control confounding factors. A secondary analysis used the same endpoints to compare metaphyseal-anchored (short stems) versus Corail-like stems.

RESULTS

After adjusting for the propensity score, we found 11.17% mechanical complications in the uncemented group (n=40, 5.59% subsidence, and 5.59% fractures) versus 13.42% for the cemented group (n=42, 7.99% subsidence, and 5.43% fractures). There was no statistically significant difference between the 2 values (Odds Ratio [OR]=0.64 [95% Confidence Interval [CI]: 0.14-2.85] [p=0.7]). The mortality rate due to cement embolism was 1%. There was no difference in the rate of subsidence (OR=0.55 [95% CI: 0.02-12.5] [p=0.7]), periprosthetic fracture (OR=0.65 [95% CI: 0.13-3.12] [p=0.7]) or infection (OR=0.71 [95% CI: 0.32-1.55] [p=0.4]). However, the operative times were longer in the cemented group (p=0.03 for hemiarthroplasties [mean additional time 16minutes] and p=0.02 for total hip arthroplasties [mean additional time 22minutes]). No difference was observed between the metaphyseal-anchored (short stems) and Corail-like stems regarding operative time, rate of infection, and rate of stem subsidence or periprosthetic fractures.

DISCUSSION

This is one of the first studies to highlight cemented stem subsidence when used for femoral neck fractures in elderly patients. Using uncemented stems in this indication is still warranted, especially since they do not bring about more mechanical complications in the first few months. Metaphyseal-anchored short stems seem to give the same results as "standard" stems. However, these findings need to be assessed in the longer term.

LEVEL OF EVIDENCE

III; retrospective comparative study.

Single-use versus reusable ancillaries for dual mobility cup in total hip replacement. A prospective randomized short-term safety and feasibility comparison

BACKGROUND

Single-use (SU) ancillaries for cup preparation in total hip arthroplasty (THR) aim to reduce the costs of hip replacement surgery. These devices have been recently introduced, but their safety and feasibility have not been studied. Therefore, we performed a prospective randomized study aiming to assess the impact in our department of using these SU ancillaries versus standard reusable ancillaries for dual mobility THR regarding 1) the cost, 2) operative time, 3) quality of primary fixation.

HYPOTHESIS

We hypothesized that the use of SU ancillaries for acetabular preparation would reduce maintenance costs, and so optimise the operating procedure, reduce the overall cost of surgery, save time, while maintaining the same quality of prosthesis fitting.

METHOD

We conducted a randomised, controlled, open-label, two-arm, single-centre, prospective therapeutic trial with a medico-economic objective. Inclusions were made prospectively from patients hospitalised and surgically managed in our department for arthrosis over 18 years old treated with dual mobility THR.

RESULTS

In the current study, 18/20 (90%) of the cases required the use of one SU reamer when using SU ancillaries. Only two cases (10%) required a second SU reamer (without SU failure regarding the acetabular implant) because there was too much subchondral bone left and not enough cancellous bone allowing correct cup fitting. We also found that the test implant supplied in the SU kit had a less secure press-fit than the reusable metal test implants. There was one of primary press-fit failure in the SU group requiring a different cup with additional screws. The estimated cost to the supplier per procedure was 20,105 euros using single-use reamers versus 26,666 euros using conventional ancillary kits, a saving of 6561 euros (p<0.001). For the healthcare institution, the median price per intervention on the differentiating points was 2648 euros versus 2580 euros, with no significant difference (p=0.297). The results show an average societal cost of 52,199 euros using single-use and 53,572 euros using reusable ancillary equipment, with a significant difference between the two groups (p<0.003). The average cost of Healthcare Risk Waste (HCRW) disposal in the SU group was 5.2 euros per intervention against 5.1 euros in the RU group, without significant difference (p=0.910). We found a similar result for the cost of disposal of non-HCRW waste per procedure: 0.37 euros in the SU group versus 0.34 in the RU group, without significant difference (p=0.345).

CONCLUSION

SU ancillaries significantly reduce the table set up time and have the potential to facilitate time and cost savings but further research is needed in this direction. Our study shows that the daily workload, operating times, and the number of boxes of instruments to be sterilised are decreased. The associated environmental gain is significant. Nevertheless, the economic promise of these SU ancillaries is only partially supported in this trial owing to the small number of patients. Further work will be needed to obtain a more powerful medico-economic assessment of this promising ancillary product.

LEVEL OF EVIDENCE

II; prospective randomized study.

Total hip arthroplasty reduces the risk of dislocation after femoral neck fracture

INTRODUCTION

Femoral neck fracture in the elderly patient can either be managed using hemi-arthroplasty (HA) or total hip arthroplasty (THA). The aim of this study was to explore the rate of three selected complications in each procedure: is the dislocation rate higher with HA compared to THA? Is the blood transfusion rate higher with THA compared to HA? Do the patients who underwent THA require more ICU transfer than the patients who underwent HA? Is the ICU transfer correlated to the use of cement for stem fixation?

METHOD

Based on a national health-care database, a comparative and retrospective study was conducted. 96,184 patients were included after having a surgery for femoral neck fracture between 2014 and 2017. The mean follow up was 3.5 years (Min. 2 years-Max. 5 years). The population was divided into two groups: hemiarthroplasty (HA) and total hip arthroplasty (THA). The primary outcome was the dislocation rate and the secondary outcomes were the blood transfusion rate and the need for ICU after surgery.

RESULTS

At two years of follow up in the Hemiarthroplasty group, 3647 patients had a dislocation episode over 64,106 patients: 5.69%. In the Total Hip Arthroplasty group: 1904 patients had a dislocation episode over 32,078 patients: 5.94% (p=0.26711). The percentage of deceased patient without dislocation was 17.76% in the HA group and 11.56% in the THA group (p<0.001). The univariate hazard ratio for dislocation was higher in the THA group: HR 1.063 IC 95% (0.993-1.138) p=0.077. The multivariate analysis calculating competitive risk with death and dislocation found THA to be a protective factor of dislocation HR 0.926 IC 95% (0.866-0.991) p=0.0266. The rate of blood transfusion was 5.59% in the THA group and 7.03% in the HA group (p<0.001), The multivariate analysis found HR=1.062 IC 95% (0.99-1.139) p=0.0955. The need for ICU transfer after the surgery was 7.04% in the HA group and 8.08% in the THA group (p<0.001). The multivariate analysis found HR 0.995 IC 95% (0.921-1.076) p=0.9094. Finally, only cement was found as an independent risk factor of ICU transfer after surgery: HR 1.254 IC 95% (1.164-1.35) p<0.0001.

CONCLUSION

THA for femoral neck fracture allows to reduce the risk of dislocation compared to hemiarthroplasty. The multivariate analysis failed to prove the superiority of one procedure over the other regarding blood transfusion risk and the need for ICU transfer. The use of cemented stem appears to be a risk factor of ICU transfer after hip arthroplasty.

LEVEL OF EVIDENCE

III, Retrospective comparative study.