SuperPath / Superior-Capsulotomy Approach to the Hip

What it exposes The SuperPath (supercapsular percutaneously assisted total hip) approach is a tissue-sparing posterior approach to the hip. It accesses the joint through the interval between gluteus minimus and piriformis, retracting the abductors anteriorly rather than detaching them. The superior and postero-superior femoral neck and the acetabulum are reached through the superior capsule; the hip is prepared in situ without dislocation, the short external rotators and iliotibial band are preserved, and the capsule is repaired. It is a modified posterolateral approach used principally for primary total hip arthroplasty. ### Why this approach is chosen SuperPath was designed to maximise tissue preservation during posterior-approach total hip arthroplasty. By using the interval between gluteus minimus and piriformis, retracting the abductors anteriorly, and preparing the femur in situ without dislocating the hip, the short external rotators and the iliotibial band are left intact and the posterior capsule can be repaired. These features theoretically reduce postoperative dislocation risk, blood loss and surgical trauma, and support earlier mobilisation and shorter hospital stay. It is extensile and converts readily to a standard posterior approach if exposure is inadequate. ### Indications - Primary total hip arthroplasty for osteoarthritis (the dominant indication)

• Total hip arthroplasty or hemiarthroplasty for displaced femoral neck fractures in suitable patients
• Osteonecrosis of the femoral head (late stage) requiring arthroplasty
• Selected developmental dysplasia cases (low or moderate dysplasia) where exposure is adequate
• Surgeons seeking a tissue-sparing, muscle-preserving posterior approach with rapid early recovery ### Contraindications - Complex revision arthroplasty requiring wide exposure of the femur or acetabulum
• Severe hip dysplasia (high dislocation, Hartofilakidis type C / Crowe IV) where extensive soft-tissue release and femoral shortening are needed
• Marked hip stiffness or ankylosis where in-situ preparation is not possible
• Severe obesity where the limited incision cannot safely reach the joint (relative; the slot technique is sometimes favourable in obese patients)
• Need for posterior column or extended acetabular exposure (consider a standard extensile approach)
• Active local infection or compromised posterior skin ### Alternative approaches - Standard posterior / posterolateral approach — widest posterior exposure but divides the short external rotators
• Direct anterior approach (DAA) — internervous (sartorius / tensor fasciae latae), muscle-sparing, supine, but requires specialised table in many centres and has its own learning curve
• Anterolateral (Watson-Jones) / Hardinge (transgluteal) — abductor-splitting, no posterior dislocation risk but risks abductor deficiency
• Mini-incision posterior — short incision but still violates the external rotators ### The tissue-sparing hip approach family

Templating and investigations Standard AP pelvis and AP and lateral hip radiographs are used to template femoral stem size, neck cut level, offset and leg length, and acetabular cup size and anticipated centre of rotation. A lateral (cross-table) view assesses femoral anteversion and the posterior femoral neck. CT is reserved for complex anatomy, severe dysplasia or revision planning; MRI rarely, for osteonecrosis staging. Routine anaesthetic workup (ECG, bloods) confirms fitness for the lateral position, with optimisation of modifiable factors (anaemia, anticoagulation, glycaemic control, smoking).

Work down through the layers over the posterior half of the greater trochanter, split the fascia lata and gluteus maximus, and develop the piriformis-sparing interval between gluteus minimus and piriformis to reach the superior capsule — then prepare the femur in situ and repair the capsule.

Structures at risk, by layer

Nerve injury management: - Superior gluteal nerve injury — abductor weakness, Trendelenburg gait; prevention is the only effective management. Avoid aggressive retraction of gluteus minimus.

• Sciatic / peroneal injury — document baseline, avoid posterior retractor pressure, investigate with EMG and nerve conduction studies if a post-operative deficit occurs, and counsel on prognosis (many neurapraxias recover). SuperPath series report peroneal nerve palsy as a recognised but uncommon complication, usually recovering over months. ### Extensile options Proximal extension: extend the incision along the line toward the ilium to improve abductor and acetabular exposure — useful in larger patients or when cup insertion is difficult, but increased abductor retraction raises superior gluteal nerve risk, so protect the interval. Distal extension: extend along the femoral shaft for diaphyseal femoral preparation or cable or plate fixation, converting toward a standard posterolateral exposure if needed. Conversion to a standard posterior approach: if exposure is inadequate, the approach is readily extended into a standard posterolateral or posterior approach by dividing the short external rotators and posterior capsule (tagging them for repair) — this safety net means the surgeon is never committed to an inadequate exposure. Accessory percutaneous portal (PATH component): a small stab incision allows percutaneous acetabular reaming and cup insertion along the correct mechanical axis, reducing soft-tissue trauma at the acetabulum but adding reliance on instrumentation and imaging. ### Closure and post-operative care The capsule is repaired first (the signature step), then the gluteus maximus split is reapproximated if significant, followed by the fascia lata, subcutaneous tissue and skin. Post-operatively, document sciatic / peroneal and abductor function versus baseline and inspect the wound at 24 to 48 hours. Most protocols allow weight bearing as tolerated from day zero for uncemented stems (follow the implant-specific protocol). Because the posterior soft-tissue envelope is preserved and repaired, posterior hip precautions are often reduced or omitted compared with a standard posterior approach — follow the operating surgeon's protocol. VTE prophylaxis is given per institutional protocol. Follow-up is typically at 2 weeks (wound check), 6 weeks (radiographs and functional assessment), then 3 months and 1 year (radiographs and outcome scoring). ### Complications

Outcomes and evidence

• Total hip replacement — SuperPath / SuperCap tissue-sparing posterior approach — the principal operation done through this exposure.
• Hemiarthroplasty or total hip arthroplasty for selected displaced femoral neck fractures.
• Total hip arthroplasty for late-stage osteonecrosis of the femoral head with secondary arthritis.
• Selected low-grade developmental dysplasia where exposure is adequate.

The SuperPath approach is a tissue-sparing posterior approach to the hip, presented by Chow in 2011 by combining the SuperCap (Murphy) and PATH (Penenberg) techniques. The patient is in strict lateral decubitus with the operated leg in the home position, and the hip is never dislocated. A 6 to 8 cm superior incision centred over the greater trochanter is deepened through the fascia lata and a gluteus maximus split, and the deep interval is developed between gluteus minimus (retracted anteriorly with gluteus medius) and piriformis (preserved) to reach the superior capsule. A superior capsulotomy exposes the femoral neck; the neck is cut and the femur broached in situ, then the acetabulum is prepared (sometimes via a percutaneous portal). The piriformis and short external rotators are preserved and the capsule is repaired, which underpins the reported low dislocation risk and rapid recovery. The superior gluteal nerve is the key structure at risk as it runs between gluteus medius and minimus.

Guidelines, registries and global practice Total hip arthroplasty is performed worldwide, and approach choice is guided by surgeon experience, patient factors and institutional resources across examination systems (advanced orthopaedic practice, DNB / MS, MRCS, SICOT). Tissue-sparing approaches such as SuperPath aim to preserve the posterior soft-tissue envelope; the comparative evidence is converging but long-term data are still maturing.