Anatomy of the greater trochanteric 'bald spot': a potential portal for abductor sparing femoral nailing?

Soft tissue injury occurs when using a piriformis portal for femoral nailing. Standard trochanteric portals also can injure the gluteus medius and external rotator tendons, which may be a source of hip pain after nailing. On the lateral facet of the greater trochanter, a "bald spot" may exist that is devoid of tendon insertion. This may be a potential portal for intramedullary nail insertion. We defined the dimensions and location of this region. Cadaveric specimens were dissected to expose the tendon insertions on the greater trochanter. A computer navigation system was used with a stylus and bone morphing to determine the tendon insertions and bald spot anatomy. The greater trochanteric bald spot is covered by the subgluteus medius bursa and has no tendon insertions. Its center lies 11 mm distal to the tip of the greater trochanter and 5 mm anterior to the midline. The shape is ellipsoid with a diameter of 21 mm. This region is large enough to accommodate the size of most nailing system reamers without tendon footprint infringement. Use of this modified entry site may reduce soft tissue injury with nailing procedures and minimize subsequent hip pain.