What HemiSPAIRE actually means for fracture patients

A hip fracture — most often a break at the femoral neck, just below the ball of the joint — is rarely planned for. When a fall leads to surgery within hours, the questions that follow are different from those surrounding an elective procedure: Will I walk again? How quickly? What exactly are they replacing?

The answer, for most displaced femoral neck fractures, is a hemiarthroplasty: a partial hip replacement in which the ball and stem are replaced but the acetabular socket is left intact. It is a faster operation than a full hip replacement and better suited to the acute setting. What patients and families are less often told is that how the surgeon reaches the hip joint can be just as consequential as what is implanted.

SPAIRE — which stands for Saving Piriformis And Internus, Repairing Externus — was first described in 2016 for elective total hip replacement. Lee et al. subsequently adapted the same principle for hemiarthroplasty, giving rise to what is now called HemiSPAIRE. The core idea is unchanged in both settings: the piriformis and obturator internus tendons at the back of the hip are preserved rather than detached, and the obturator externus is repaired, keeping the soft-tissue envelope around the joint as intact as possible.

This is clinically significant because NICE recommends the lateral approach for hip fracture hemiarthroplasty specifically to reduce dislocation risk — a risk that can reach 10% with a standard posterior approach in some published series. HemiSPAIRE seeks to retain the functional advantages of a posterior approach without incurring that dislocation penalty. For a frail patient who needs to stand the following morning, an approach that protects hip stability from the outset can directly affect whether early mobilisation is safe to attempt.

Over 20,000 hip hemiarthroplasties are carried out annually in the UK, making this a high-volume decision. The clinical approach informing the content on this site — including the distinction between the fracture pathway and the elective SPAIRE total hip replacement pathway — draws on Prof Paul Lee's specialist experience with both.

Who is suitable for HemiSPAIRE after a hip fracture

Broadly speaking, HemiSPAIRE is applicable to most patients who are already candidates for hemiarthroplasty. The initial case series by Lee et al. (2017) established that the muscle-sparing posterior approach is feasible across the full range of skeletal dimensions and body mass indices — no particular body type is excluded on anatomical grounds alone.

The primary indication is a displaced intracapsular femoral neck fracture in a patient whose hip joint warrants hemiarthroplasty rather than fixation. Beyond that straightforward starting point, however, suitability involves several layers of clinical judgement.

Technical complexity. Certain anatomical factors increase the demand of the procedure: a reduced femoral offset, small hip anatomy, or a significant external rotation deformity can each make instrument access and implant positioning less straightforward. In these cases, robotic assistance has been used alongside SPAIRE to improve accuracy, though the combination requires appropriately equipped facilities and surgical experience.

The fracture patient population. Hip fracture patients are not simply younger elective patients in a hurry. They tend to be older, frequently have osteoporotic bone, and arrive in surgery with comorbidities that influence anaesthetic risk, implant selection, and the expected pace of recovery. These factors form part of any honest suitability assessment.

Hemiarthroplasty or total hip replacement? This is a live clinical question independent of approach. A 2025 overview of 20 systematic reviews (29,980 patients) found that total hip replacement for displaced femoral neck fractures yields a lower revision rate and better early function, but adds approximately 20 minutes of operative time compared with hemiarthroplasty. Whether that trade-off is appropriate depends on individual frailty, activity level, and surgeon assessment — it is not a decision patients should reach without specialist input.

How the muscle-sparing posterior approach differs from standard options

Three distinct routes to the hip joint are most relevant in fracture surgery, and each involves a different trade-off between stability and muscle preservation.

The standard posterior approach reaches the hip from behind through the same general territory as SPAIRE, but detaches the piriformis, obturator internus, and obturator externus tendons to gain access. Posterior capsular repair has reduced dislocation rates considerably, yet some published series still report rates reaching 10% — one reason NICE guidance steers towards the lateral route for fracture cases.

The lateral (Hardinge) approach avoids the posterior capsule entirely, which lowers dislocation risk. The trade-off is that it splits the gluteus medius — the main abductor of the hip — which can weaken the muscle responsible for level walking. In elderly patients, even a modest reduction in abductor strength may affect gait and confidence during early mobilisation.

SPAIRE — the muscle-sparing posterior approach uses the same posterior incision as the standard posterior technique but preserves the piriformis and obturator internus tendons completely. Only the obturator externus is divided, and it is repaired at the close of the procedure. The soft-tissue envelope stabilising the hip remains largely intact from the outset, rather than being reconstructed after deliberate division.

SPAIRE is not an anterior approach and should not be confused with the direct anterior approach (DAA) or SuperPATH, which enter the hip from the front between muscle planes. The approach is posterior; the distinction from the standard posterior technique lies entirely in which tendons are divided.

In the context of hip fracture, minimising additional soft-tissue disruption carries particular weight. Elderly, frail patients with osteoporotic bone and reduced muscle bulk are least able to compensate for iatrogenic tendon damage — making tendon preservation potentially more meaningful in this population than in younger elective patients. How that translates into measurable functional outcomes is addressed by the evidence in the section that follows.

What the clinical evidence shows

The Norwegian registry study of 858 femoral neck fracture patients provides the strongest comparative data currently available. Against the direct lateral approach, HemiSPAIRE produced a dislocation rate of 0.7% versus 0.9% — no statistically meaningful difference — alongside equivalent rates of surgical site infection and 30-day mortality. Where the approaches diverged was at three months: SPAIRE patients scored 6.1 versus 5.0 on the New Mobility Score, 7.3 versus 5.9 on the Short Physical Performance Battery, and walked at 0.8 versus 0.7 m/s (all p<0.001).

A smaller single-centre retrospective analysis of 194 cases reinforces the dislocation picture: zero dislocations in the SPAIRE group compared with 2% in the anterolateral and 3.7% in the standard posterior groups. Mean time to mobilisation was 1.4 days with SPAIRE versus 2.0 and 2.6 days respectively, with broadly similar operative times across all three groups.

The 2025 systematic review, pooling 1,385 hips, found that SPAIRE's short-term advantages in early mobility and pain management do not translate into significant long-term differences in function, patient-reported outcomes, or discharge destination. This is important for calibrating expectations: SPAIRE in fracture patients is about the quality and pace of early recovery, not a different long-term endpoint.

A separate RCT of 158 femoral neck fracture patients — comparing SPAIRE with the direct anterior approach on periprosthetic bone mineral density at 3 and 12 months — found equivalent changes between the two techniques, with no signal of increased periprosthetic fracture risk from either approach.

The NIHR-funded HIPSTER trial, which pairs robotic-assisted SPAIRE with the MAKO system against the standard posterior approach, is ongoing in the elective total hip replacement setting; its results are not yet available and do not currently inform fracture-specific decision-making.

For patients weighing their options now, the existing body of evidence points consistently in one direction: HemiSPAIRE matches the lateral approach on safety and matches or exceeds it on early functional recovery, without introducing additional risk to bone or implant stability.

Recovery after hip fracture arthroplasty vs planned hip replacement

For families wondering whether SPAIRE after a fall will feel different from a planned operation, the honest answer is yes — and the reasons lie largely outside the technique itself.

Four differences shape recovery in fracture patients compared with elective SPAIRE total hip replacement:

Patient profile. Fracture patients are typically older and frailer, often with osteoporotic bone and multiple comorbidities. Elective patients frequently complete a structured prehabilitation programme before surgery — building strength and cardiovascular fitness that raises their functional starting point considerably.

The operation itself. HemiSPAIRE for fracture preserves the acetabular socket, replacing only the femoral head. Elective SPAIRE replaces both components. These are meaningfully different procedures with different recovery trajectories, independent of which approach is used.

Surgical urgency. NICE recommends hip fracture surgery within 36 to 48 hours of admission. There is no window to optimise nutrition, adjust medications in a planned way, or begin pre-operative physiotherapy — all of which are routine preparation in elective care.

Rehabilitation baseline. Fracture patients begin recovery from an acute injury, with pain, muscle inhibition, and the physiological effects of an emergency admission. Elective patients start from a pre-planned, typically stronger position.

Where SPAIRE makes a meaningful difference in this context is in early mobilisation. Evidence suggests fracture patients get up approximately a day sooner with SPAIRE than with conventional approaches — clinically significant in a population where immobility carries risks including pneumonia, pressure injury, and rapid deconditioning. The long-term functional endpoint, however, is broadly equivalent whichever approach is used: the technique improves the recovery curve; it does not change where that curve ends.

Seeking assessment and what to ask your surgeon

Emergency fracture pathways move quickly — the operating surgeon and the centre's protocols determine which approach is used, and SPAIRE availability depends on the individual team's training. For patients already admitted with a hip fracture, direct questions to the surgical team are the most practical step.

For those planning ahead — whether because of osteoporosis, recurrent falls, or a wish to understand their options before any fracture occurs — and for patients seeking follow-up care after fracture surgery, the same questions apply in a more considered setting:

• Is hemiarthroplasty or total hip replacement planned, and what guides that decision?
• Which surgical approach does your surgeon use, and why?
• What dislocation precautions, if any, will apply after surgery?

The SPAIRE content on this site reflects the clinical approach of Prof Paul Lee, whose muscle-sparing technique and surgeon-led assessment of individual hip anatomy underpin the evidence discussed throughout.

If you want to discuss these questions with a specialist who uses this approach, Lincolnshire Hip — based across Sleaford and Grantham and part of the MSK Doctors group — accepts patients without a GP referral for hip assessment. The goal is a clear, informed picture of your options: what has happened to the hip, what the evidence supports, and what the right next step looks like for your specific situation.

1. [1] Functional outcomes and complication rates of the SPAIRE approach compared to the direct lateral approach in hemiarthroplasty for displaced femoral neck fractures. (2025). https://doi.org/10.1016/j.injury.2025.112339 https://doi.org/10.1016/j.injury.2025.112339
2. [2] Detailed statistical analysis plan for the HemiSPAIRE randomised controlled trial. (2022). https://doi.org/10.1186/s13063-022-06790-z https://doi.org/10.1186/s13063-022-06790-z
3. [3] The SPAIRE Technique for Hip Hemiarthroplasty — An Alternative Approach to the Hip. (2023). https://doi.org/10.1093/bjs/znad258.669 https://doi.org/10.1093/bjs/znad258.669
4. [4] Details of a Tendon–Sparing Posterior Approach in Hemiarthroplasty in the Treatment of Displaced Intracapsular Neck of Femur Fracture. (2017). https://doi.org/10.4172/2167-7921.1000243 https://doi.org/10.4172/2167-7921.1000243
5. [5] Rethinking Hip Surgery: A Systematic Review of SPAIRE vs. Traditional Hemiarthroplasty Approaches. (2025). https://doi.org/10.7759/cureus.89115 https://doi.org/10.7759/cureus.89115
6. [6] Total hip arthroplasty versus hemiarthroplasty for displaced femoral neck fracture: an overview of systematic reviews. (2025). https://doi.org/10.1186/s13018-025-06144-w https://doi.org/10.1186/s13018-025-06144-w