Total Hip Replacement - SuperPATH/SuperCAP Approach (Tissue-Sparing Posterior)

Indication. Symptomatic hip arthritis in a well-selected patient who wants rapid recovery and meets the anatomical criteria for a tissue-sparing approach. The ideal candidate has primary osteoarthritis with normal proximal-femur anatomy and a spherical head, a BMI less than 35, good bone quality and a small-to-medium femoral head. It also suits avascular necrosis with minimal head collapse (Ficat I to III), an elderly femoral-neck fracture with normal proximal-femur anatomy, and closely staged bilateral THR (2 to 4 weeks apart) where tissue preservation matters.

The one principle that defines the approach. SuperPATH (Superior Portal Assisted Total Hip) is one end of a continuum of posterior approaches — from micro (external-rotator-sparing, this technique) through mini (rotator-sacrificing) to the standard posterior. It is extensile: if exposure, anatomy or a complication demands it, you can extend the superior window and release the rotators to become a conventional posterior approach at any point. That extensility is the safety net of the technique. Consent specifically for the learning curve and a higher early technical-complication rate (femoral fracture, cup malposition, conversion to conventional in 1 to 5 percent), for dislocation being low but not zero, for possible leg-length discrepancy, and for the real possibility of conversion to a standard posterior approach if the anatomy will not cooperate. Setup. Lateral decubitus with the pelvis secured perpendicular to the table (CRITICAL — pelvic tilt is the main source of cup malposition when you cannot verify directly); a beanbag or dedicated positioner; pad bony prominences. Drape the C-arm into the field (strongly recommended, especially during the learning curve). Standard arthroplasty antibiotics and skin prep. Re-confirm templated cup size, stem size, offset and neck length before draping — intra-operative correction is hard through a small window.

The goal: replace the hip through a 6 to 10 cm posterolateral incision by developing the gluteus-minimus-to-piriformis interval, creating a 3×4 cm superior capsular window, cutting the femoral neck in situ, preparing and implanting both components through that window, and leaving the external rotators and posterior capsule intact — so that nothing needs repairing and the hip is inherently stable. The exposure is laid out as the opening steps below (and is extensile to the posterior (Moore/Southern) approach to the hip if needed).

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Rapid-recovery rehabilitation | Phase | Timing | Mobilisation and precautions | Imaging and milestones | |-------|--------|------------------------------|------------------------| | 1 | Day 0 | Full weight bearing as tolerated, NO hip precautions, walker or crutches; multimodal pain control | — | | 2 | Day 1 | Discharge home is common (outpatient or 23-hour protocols); continue PT | — | | 3 | Week 2 | Wound check; staple or suture removal if used | — | | 4 | Week 6 | Progressive return to activity | AP pelvis and lateral hip X-ray: component position, occult fracture, heterotopic ossification | | 5 | Month 2 to 4 | Driving from about 2 to 4 weeks; desk job 3 to 4 weeks, manual 6 to 8 weeks; low-impact sport sooner, high-impact by 3 to 4 months | Clinical review | DVT prophylaxis. LMWH (enoxaparin 40 mg daily) or a DOAC (rivaroxaban, apixaban) for 35 days plus mechanical prophylaxis (TED stockings, intermittent pneumatic compression) and early mobilisation — the same protocol as conventional THR, with the SuperPATH advantage of walking on day 0. Heterotopic ossification runs 5 to 15 percent (LOWER than the 10 to 25 percent of a conventional posterior approach, because there is less soft-tissue trauma). In high-risk patients (ankylosing spondylitis, DISH, previous HO, hypertrophic OA), give prophylaxis — indomethacin 25 mg three times daily for 6 weeks, or a single 7 to 8 Gy radiation dose within 72 hours. Complications

Approach choice is surgeon-dependent, not country-specific. The major national societies (AAOS, BOA or BOAST, AO Foundation, EFORT) do not mandate a single THA approach; the posterior, direct anterior, anterolateral and tissue-sparing (SuperPATH) variants are all accepted, and the evidence shows the approach matters most for early recovery rather than for long-term survivorship. Registry context. The large arthroplasty registries (NJR for England and Wales, AOANJRR for Australia, AJRR for the US, SHAR for Sweden) track survivorship by fixation and bearing rather than by minimally invasive sub-technique. SuperPATH uses the same cementless cups and stems as the standard posterior approach, so the registry survivorship data for those implants apply; dedicated long-term SuperPATH-specific registry survivorship remains limited because it is a relatively newer, lower-volume technique. Key evidence points 1. Dislocation around 0.8 percent — in the largest cited multicentre series of 479 hips (Gofton 2014), with several series reporting no dislocations at all; attributed to the preserved posterior capsule and external rotators. 2. Periprosthetic femoral fracture is the dominant intra-operative risk — about 0.8 percent in the 479-hip series and 4 of 344 (about 1.2 percent) in the Flevas series; it is the complication most directly tied to limited-visualisation femoral preparation. 3. Faster early recovery, equivalent positioning — Level I and II evidence (the Xie RCT; the Ramadanov network meta-analysis) shows a shorter incision, less blood loss, a shorter stay and lower early pain, with cup abduction and anteversion equivalent to conventional and direct anterior approaches. 4. Early advantages are not sustained — Harris Hip Score and functional differences versus the standard posterior approach resolve by one year (Xie RCT). 5. Same implants, registry data transfer — SuperPATH uses the same cementless components as the standard posterior approach, so implant-specific registry survivorship applies; dedicated long-term SuperPATH survivorship data remain limited. Beyond elective OA. A randomised trial (Jia et al., Injury 2019) and a meta-regression of five RCTs (Ramadanov et al., Orthop Surg 2024) found SuperPATH hemiarthroplasty for neck-of-femur fracture gives smaller incisions, less blood loss and faster early function, with elderly patients (over 70) appearing to benefit most — supporting its use beyond elective OA. A contemporary single-surgeon series (Flevas et al., Life 2022) reported 344 cases with a mean stay of 1.3 days, no dislocations and no infections; complications were four intra-operative femoral fractures and two peroneal nerve palsies — reinforcing that the dominant intra-operative risk is the proximal femur, not instability.