Introduction: Hip dislocation is a devastating complication after total hip arthroplasty (THA), which is slightly higher when using the traditional posterior approach. The piriformis tendon is the most important dynamic posterior stabilizing structure. The piriformis-sparing technique provides a reproducible method for THA, greatly reducing the dislocation rate.
Materials and methods: After exposure and identifying piriformis, the inferior border of the piriformis is released from the short rotators and capsule with a BOVIE® (Symmetry Surgical, Inc, Nashville, Tennessee). This dissection is continued to the lesser trochanter as one sleeve and then tagged. The anterior/inferior capsule is released with a BOVIE® from the femur to aid in acetabular exposure. The femur is roughly placed in 30° of adduction, 70° of flexion, and slight internal rotation. An anterior retractor is used to displace the proximal femur anteriorly and superiorly. The reamer is placed inside the acetabulum through the inferior approach. Next, the acetabulum is progressively reamed to the appropriate size and depth, and the final component is placed in proper anteversion and abduction angles based on preoperative functional assessment. After insertion of final components and final hip reduction, the interval beneath the piriformis tendon and superior portion of the capsule is repaired with ETHIBOND® sutures (Johnson & Johnson Inc., New Brunswick, New Jersey). Then, two tunnels in the proximal femur with a 2.7mm drill bit is made and posterior capsule and short rotators are secured through these tunnels.
Results: This technique was used in 150 THAs with a minimum follow up of six months and a mean of 1.2 years ± 1.5 years. There was no dislocation at final follow up. The mean anteversion and abduction was 23 ± 2.7 and 42 ± 3.1, respectively.
Conclusion: Preserving the piriformis tendon may cause less visualization of the superior portion of the acetabulum. However, the anterior/inferior capsular release, and proper placement of the femur with flexion, internal rotation, and adduction, makes it possible to achieve highly reproducible results.
Vinay Hosuru Siddappa 1, Morteza Meftah 2
1Department of Orthopedic Surgery, Baylor College of Medicine, Houston, Texas.
2Department of Orthopaedic Surgery, NYU Langone Orthopedic Hospital, New York, New York.
Surg Technol Int. 2020 May 28;36:360-363.