The use of a modified posterior approach (SPAIRE) may be associated with an increase in return to pre-injury level of mobility compared to a standard lateral approach in hemiarthroplasty for displaced intracapsular hip fractures: a single-centre study of the first 285 cases over a period of 3.5 years

A piriformis-preserving posterior approach reduces dislocation rate of the hemiarthroplasty in patients with femoral neck fracture

INTRODUCTION

The posterior approach (PA) for hemiarthroplasty (HA) in patients with femoral neck fracture (FFN) has a high risk of dislocation; however, by preserving the piriformis muscle, the dislocation rate could be lowered considerably. The aim of this study was to compare the surgical complications of the piriformis-preserving posterior approach (PPPA) and the PA in patients with FNF treated with HA.

METHODS

On 1 January 2019, the PPPA was introduced at two hospitals as the new treatment standard. The sample size was calculated based on a 5 percentage point dislocation reduction and 25% censoring; a sample of 264 patients per group was determined. An approximately 2-year inclusion period with 1-year follow-up was estimated, including a historical cohort from 2 years before the PPPA introduction. Data were retrieved from health care records and X-ray images from the hospitals' administrative databases. Relative risk (RR) and 95% confidence intervals were calculated using Cox regression and adjusted for age, sex, comorbidity, smoking, surgeon experience and implant type.

RESULTS

There were 527 patients included in the study, of which 72% were women and 43% were above 85 years old. There were no baseline differences between the PPPA and PA groups in sex, age, comorbidity, body mass index, smoking, alcohol, mobility, length of surgery, blood loss or implant positioning, but there were differences in 30-day mortality, surgeon experience and implant type. The dislocation rate reduced from 11.6% in the PA group to 4.7% in the PPPA group (p = 0.004), with an RR of 2.5 (1.2; 5.1). The reoperation rate reduced from 6.8% with the PA to 3.3% with the PPPA (p = 0.022), with an RR of 2.1 (0.9; 5.2), and total surgery-related complications reduced from 14.7% with the PA to 6.9% with the PPPA (p = 0.003), with an RR of 2.4 (1.3; 4.4).

INTERPRETATION

Changing from PA to PPPA in patients with FNF treated with HA resulted in a more than 50% reduction in dislocation and reoperation rates. This approach was easily introduced and may enable further lowering of dislocation rates through the sparing of all short external rotators.

The Modified Spare Piriformis and Internus, Repair Externus Approach for Hip Arthroplasty

We present the case of an 80-year-old Malaysian gentleman who sustained a displaced intracapsular neck of femur (NOF) fracture and underwent a modified SPAIRE (Sparing Piriformis and Internus, Repair Externus) approach for total hip replacement (THR). The standard approach used in our hospital for THR in NOF fractures is the modified Hardinge approach to the hip. We used this modified SPAIRE approach as this patient lives in a 'Mahjong' center and always sits cross-legged on the floor. Therefore, he is at increased risk of an anterior dislocation. This approach is a modification of the standard SPAIRE approach popularized by the Exeter Hip Unit, United Kingdom. In this report, we describe the modification of the SPAIRE approach that has not been described before and the outcome for this patient.

Detailed statistical analysis plan for a randomised controlled trial of the effects of a modified muscle sparing posterior technique (SPAIRE) in hip hemiarthroplasty for displaced intracapsular fractures on post-operative function compared to a standard lateral approach: HemiSPAIRE

Background

The HemiSPAIRE trial is being conducted to determine whether a modified muscle sparing technique (SPAIRE-“Save Piriformis and Internus, Repairing Externus”) in hip hemiarthroplasty brings clinical benefits compared to the standard lateral technique in adults aged 60 years or older, with a displaced intracapsular hip fracture. This article describes the detailed statistical analysis plan for the trial. 

Methods and design

HemiSPAIRE is a definitive, pragmatic, superiority, multicentre, randomised controlled trial (with internal pilot) with two parallel groups. Participants, ward staff and all research staff involved in post-operative assessments are blinded to allocation. This article describes in detail (1) the primary and secondary outcomes; (2) the statistical analysis principles, including a survivor average causal effect (SACE) method chosen specifically to address the issue of potential bias from differential survival between trial arms, which was seen from data review by the Trial Steering Committee, the participants that will be included in each analysis, the covariates that will be included in each analysis, and how the results will be presented; (3) planned main analysis of the primary outcome; (4) planned analyses of the secondary outcomes; and (5) planned additional analyses of the primary and secondary outcomes.

Trial registration

ClinicalTrials.gov NCT04095611. Registered on 19 September 2019.