Two posterior approaches, one shared goal

If you have been researching muscle-sparing hip replacement, you may have come across both SPAIRE and SuperPATH and wondered whether they amount to the same thing. They share a clear family resemblance — but they are distinct techniques with different anatomies, different instrumentation requirements, and different evidence bases.

Both approaches belong to the same posterior family of hip replacement surgery, and both were developed in direct response to a recognised weakness of the traditional posterior approach: the cutting of several short tendons behind the hip, which historically required patients to follow strict movement restrictions for around six weeks after surgery to prevent dislocation. SPAIRE (Sparing Piriformis And Internus, Repair Externus) was developed at the Exeter Hip Unit in 2016 by Professor John Timperley. SuperPATH (Supercapsular Percutaneously-Assisted Total Hip) emerged in the United States around 2011. Both are now accessible to patients in the UK, though through different routes and at different centres.

Neither technique is universally available. Which approach a patient can realistically be offered depends on the surgeon's specific training and the equipment available at their centre — factors that a specialist assessment should clarify. This article maps the practical differences between the two to support that conversation, rather than to declare one approach superior to the other.

What each technique does differently inside the joint

The clearest way to understand the difference between SPAIRE and SuperPATH is to ask one question: does the hip joint need to be opened and the ball temporarily moved aside to place the new implant?

SPAIRE — one tendon divided, the joint briefly unlocked

In SPAIRE, the surgeon reaches the hip through the same posterior corridor used in conventional hip surgery, but with a critical anatomical adjustment. The piriformis and obturator internus tendons — two of the key stabilising muscles at the back of the joint — are left completely undisturbed. Only the obturator externus, a smaller tendon accessed through a natural gap between adjacent muscles, is divided and then carefully repaired at the end of the procedure. The hip joint is still dislocated briefly so the worn femoral head can be removed and the new implant seated in the normal way, using standard implant systems already familiar to most hip surgeons.

SuperPATH — the joint is never unlocked

SuperPATH takes the principle further. The surgeon navigates through the natural tissue plane above the joint capsule — without dislocating the femoral head at all. Purpose-built angulated reamers and percutaneous jigs, supplied as a proprietary MicroPort system, allow the surgeon to prepare the socket and femur and position the prosthesis entirely in situ. No tendon is divided; the surrounding soft tissues are spread aside rather than cut.

Shared setup, different kit

Both techniques position the patient on their side (lateral decubitus) and need no special traction table — a practical advantage they share over the direct anterior approach. Where they diverge is instrumentation: SPAIRE works with standard surgical equipment and can be extended without difficulty if an intraoperative complication arises, while SuperPATH depends on specialist proprietary kit that is not universally available, and carries a steeper surgical learning curve.

What the clinical evidence shows for each technique

The strongest prospective evidence for SPAIRE comes from the HemiSPAIRE multicentre RCT, conducted across six NHS hospitals in South West England (n=244). Oxford Hip Score at 120 days was statistically equivalent between SPAIRE and the standard lateral approach — meaningful reassurance that the technique does not compromise recovery — with an indication of meaningfully lower patient-reported pain at day three in the SPAIRE arm. A separate NIHR-funded trial, HIPSTER, is now comparing SPAIRE, a piriformis-sparing approach, and the standard posterior technique in elective total hip replacement, with results still pending.

A large Norwegian cohort study (n=858) adds further functional depth: at three months, patients who had SPAIRE recorded significantly better New Mobility Score (6.1 versus 5.0), Short Physical Performance Battery score (7.3 versus 5.9), and walking speed (0.8 versus 0.7 m/s) compared with those treated via the direct lateral approach. Dislocation rates were similarly low in both groups — 0.7% versus 0.9% — suggesting that preserving the tendon cuff does not come at a stability cost.

For SuperPATH, a 2025 updated systematic review and meta-analysis of nine RCTs (299 SuperPATH patients, 379 conventional) found consistent advantages in incision length, hospitalisation duration, early pain scores, and hip function. A 2023 RCT comparing SuperPATH directly with the modified Hardinge approach recorded approximately 57 ml less intraoperative blood loss, 6.7 cm shorter incision, and 2.8 fewer hospital days in the SuperPATH group, with better Harris Hip Scores at three months.

No direct head-to-head RCT between SPAIRE and SuperPATH exists, which is a normal feature of evidence at this stage of surgical development. Two further caveats are worth noting: most published SPAIRE RCT data derive from hemiarthroplasty for hip fracture rather than elective replacement for osteoarthritis, and the majority of SuperPATH RCT data originates from Chinese centres, which may limit straightforward application to a UK NHS population. Long-term implant survival figures for both techniques in large UK cohorts are still accumulating.

Recovery: what patients experience after each approach

Traditional hip precautions — no bending past 90°, no crossing the legs, no rotating the foot inward — lasted six weeks or longer under older surgical techniques and were a significant source of patient anxiety. Neither SPAIRE nor SuperPATH carries these restrictions, because the periarticular soft tissues responsible for joint stability are preserved rather than divided. Both techniques support same-day or next-day mobilisation.

Where the two differ is in the very earliest phase of recovery. SuperPATH trials consistently report shorter hospital stays — roughly two to three fewer days compared with conventional approaches — and lower early post-operative pain scores, an effect most commentators attribute to the femoral head never being dislocated during surgery. The 2025 meta-analysis of nine RCTs found these advantages reached statistical significance across multiple outcomes.

SPAIRE patients also report early pain advantages over standard posterior or lateral approaches — trial evidence suggests the effect is clinically meaningful in the first few days — though the magnitude appears somewhat less pronounced than SuperPATH's no-dislocation principle may confer.

Beyond the first week, both techniques appear to support substantially earlier return to daily activities than conventional hip replacement. Long-term functional outcomes look broadly similar across muscle-sparing approaches, though large UK long-term cohort data are still accumulating.

Recovery is, however, shaped by more than the surgical approach alone. Pre-operative fitness, physiotherapy engagement, and individual healing all influence how quickly a patient regains confidence and independence. Technique choice is one important variable — a thorough pre-operative assessment remains the most reliable way to set realistic expectations for any individual patient.

Which approach suits which patient — and why it depends on the surgeon

Answering 'which should I have?' honestly requires shifting from technique comparison to practical availability. Both approaches eliminate post-operative restrictions and support early mobilisation — but a technique available only at a handful of specialist centres is not a realistic option for most patients outside major cities.

Surgeon training and centre capability

SPAIRE works within the same posterior anatomical corridor as conventional hip replacement, using standard implant systems without proprietary instrumentation. A consultant experienced in posterior hip surgery can incorporate SPAIRE into practice more readily — making it the more broadly adoptable option across UK NHS trusts and independent sector hospitals alike. SuperPATH, by contrast, relies on the MicroPort proprietary system of angulated reamers and percutaneous jigs. The learning curve is steep and concentrated; in the UK, the technique is offered at higher-volume specialist centres, predominantly in Leicester and London.

Patient anatomy and case complexity

Hip morphology, BMI, bone quality, and prior surgery all influence which technique a surgeon can safely perform. SuperPATH's narrow operative field — achieved by never dislocating the femoral head — can limit its application in complex primary cases or where anatomy is unusual. SPAIRE, operating through familiar posterior anatomy, is more readily convertible should intraoperative circumstances change.

Access for patients outside London

For patients in Lincolnshire and the East Midlands, SPAIRE represents the more accessible muscle-sparing option. At Lincolnshire Hip, Prof Paul Lee — trained in the technique under Prof Timperley at the Exeter Hip Unit — offers consultant-led SPAIRE with consultations in Grantham and Sleaford, without requiring travel to a SuperPATH-equipped centre.

The most important variable, however, is not which technique exists on paper but which technique your surgeon knows thoroughly. Surgeon familiarity with the chosen approach is at least as important as the approach itself — which argues for specialist assessment rather than patient self-selection.

Accessing a specialist assessment at Lincolnshire Hip

A first specialist assessment for hip replacement covers more ground than technique choice alone: diagnosis confirmation, imaging review, bone quality, joint anatomy, fitness for surgery, and whether conservative management has genuinely run its course. For patients still weighing SPAIRE against SuperPATH, that same consultation will include an honest appraisal of which approach their anatomy supports and which technique is available through the surgical team being considered.

Lincolnshire Hip is part of the MSK Doctors group and accepts patients without referral for hip assessment, with clinics in Grantham and Sleaford. Prof Paul Lee's practice centres on the SPAIRE technique, which carries an active NIHR-funded RCT evidence base — an unusual level of trial scrutiny for a specialist posterior approach.

What a first assessment ultimately resolves is not which muscle-sparing technique is superior in the abstract — the evidence reviewed here does not settle that — but which approach suits this patient's specific hip, anatomy, and circumstances.

1. [1] The SPAIRE Technique Allows Sparing of the Piriformis and Obturator Internus in a Modified Posterior Approach to the Hip. (2017). https://doi.org/10.5301/hipint.5000490 https://doi.org/10.5301/hipint.5000490
2. [2] Quadriceps Coxae-Sparing Modified Posterior Approach to the Hip Joint for Hemiarthroplasty (JBJS 2026). (2026). https://doi.org/10.2106/JBJS.ST.25.00008 https://doi.org/10.2106/JBJS.ST.25.00008
3. [3] Clinical effectiveness of a modified muscle sparing posterior technique (HemiSPAIRE): a multicenter, parallel-group, randomized controlled trial. (2024). https://doi.org/10.1136/bmjsit-2023-000251 https://doi.org/10.1136/bmjsit-2023-000251
4. [4] Statistical analysis plan for HemiSPAIRE: a randomised controlled trial of modified muscle sparing posterior technique (SPAIRE) in hip hemiarthroplasty. (2022). https://doi.org/10.1186/s13063-022-06790-z https://doi.org/10.1186/s13063-022-06790-z
5. [5] 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
6. [6] Comparison of SuperPath approach versus modified Hardinge approach in total hip arthroplasty for femoral neck fractures in elderly patients: a randomized controlled trial. (2023). https://doi.org/10.1186/s13018-023-03713-9 https://doi.org/10.1186/s13018-023-03713-9