new piriformis-preserving MIS posterior STAR approach for THA

Background: Minimally invasive surgical (MIS) approaches for primary total hip arthroplasty (THA) aim to reduce soft-tissue trauma and accelerate recovery. However, limited intraoperative visualization of the acetabulum and proximal femur in some MIS techniques can increase the risk of component malposition, periprosthetic fractures, and the requirement for specialized instrumentation.

Objective: This article describes the surgical technique and clinical rationale for the Superior Transverse Atraumatic Replacement (STAR) approach, a modified MIS posterior muscle-sparing technique designed to enhance visualization and functional outcomes using standard instrumentation.

Key Points: The STAR approach utilizes a skin incision directed 45 degrees posteriorly from a point 3 cm distal to the greater trochanter tip, following Langerhans lines. The technique preserves the iliotibial band and the piriformis tendon while tenotomizing the obturator internus and gemelli. A capsular flap is created and later repaired through transosseous channels. This method provides a circumferential view of the acetabulum and direct visualization of the distal femoral intercondylar axis, facilitating precise assessment of femoral neck anteversion. The approach avoids major arterial branches, though the medial circumflex femoral artery may require cauterization. It is applicable for patients with obesity or mild-to-moderate hip dysplasia and does not require offset reamers or specialized tables.

Conclusion: The STAR approach offers a reproducible, muscle-sparing alternative for THA that maintains the piriformis tendon and posterior stabilizers. By providing unobstructed exposure with standard instruments, it facilitates accurate component positioning and may reduce the risk of instability and intraoperative complications.