CPT® Code 27100

1. Indications

The transfer of the external oblique muscle to the greater trochanter is indicated for patients with specific conditions that lead to impaired hip abduction. The following are the primary indications for this procedure:

• Abductor Paralysis - A condition where the muscles responsible for hip abduction are weakened or paralyzed, leading to difficulty in moving the leg away from the body.

2. Procedure

The procedure for transferring the external oblique muscle to the greater trochanter involves several detailed steps to ensure successful muscle repositioning and optimal recovery. The following outlines the procedural steps:

• Step 1: A long oblique skin incision is made starting from the pubic spine, extending over the iliac crest, and reaching up to the costal margin along the posterior axillary line. This incision provides access to the external oblique muscle.
• Step 2: The aponeurosis of the external oblique muscle is incised parallel to Poupart's ligament, and the incision is deepened down to the pubis. A second incision is made approximately 2 cm from and parallel to the first incision, which is then joined at the pubis.
• Step 3: Another incision is made superiorly along the medial border of the belly of the external oblique muscle to free the muscle fibers from the aponeurosis. The inferior incision is extended laterally to the anterior superior spine of the ilium.
• Step 4: The external oblique muscle is divided at its insertion on the iliac crest. The muscle belly is then freed from underlying structures using blunt dissection techniques.
• Step 5: The cut edge of the external oblique muscle is folded under and sutured to itself, ensuring that the muscle is properly positioned for the transfer.
• Step 6: The gap in the aponeurosis is closed with sutures, extending from the pubis as far laterally as possible to secure the muscle in place.
• Step 7: A lateral incision is made over the greater trochanter, where the fascia and periosteum are incised in two locations. Two drill holes are created in the greater trochanter to facilitate the muscle transfer.
• Step 8: A subcutaneous tunnel is created from the greater trochanter to the lower abdomen, allowing for the passage of the fascial tendon.
• Step 9: The fascial tendon, configured using the aponeurosis of the external oblique muscle, is passed through the tunnel to the greater trochanter.
• Step 10: The hip is placed in wide abduction, and the fascial tendon is passed through the drill holes in the greater trochanter and secured with sutures to ensure stability.
• Step 11: Finally, the incisions are closed in layers, and a spica cast is applied to maintain the hip in wide abduction during the recovery period.

3. Post-Procedure

Post-procedure care following the transfer of the external oblique muscle to the greater trochanter involves monitoring the surgical site for signs of infection and ensuring proper healing. Patients are typically advised to keep the hip in wide abduction as maintained by the spica cast. Rehabilitation may include physical therapy to restore strength and mobility in the hip joint, focusing on gradual increases in range of motion and functional activities. Follow-up appointments are essential to assess the healing process and the effectiveness of the muscle transfer in improving hip abduction.