Surgeon's Corner: Femoral Head and Neck Osteotomy (FHO)

Presentation

Craniolateral approach to the hip is used to perform femoral head and neck excision for the treatment of Legg-Calve-Perthes disease in a 10-month-old Yorkie.

Surgery

With the patient positioned in lateral recumbency, the surgeon should identify important palpable landmarks for a craniolateral approach, including the cranial margin of the ilium, ischiatic tuberosity, and greater trochanter. The skin incision will begin at approximately the dorsal margin of the ilium and extend along the cranial margin of the greater trochanter, and concluding mid-shaft of the femur.

An incision is made in the subcutaneous tissues, as well the superficial and deep leaves of the fascia lata, to reveal the superficial musculature of the hip. After incising the fascia lata between the tensor fascia lata muscle and bicep femoris, the insertion of the middle gluteal muscle on the greater trochanter can be visualized. Dorsal retraction of the middle gluteal reveals the bright, shiny white tendon of insertion of the deep gluteal muscle. This tendon is incised transversely across ~50% of its insertional width (not shown in video). A stay suture is placed in the partially tenotomized deep gluteal tendon; this suture will facilitate not only retraction of the musculature during the surgical procedure but aid in closure as well. Elevation of the deep gluteal muscle and tendon exposes the underlying joint capsule. An incision is made in the capsule, extending from the dorsal margin of the acetabular rim across the femoral head and neck, toward the approximate level of origin of the vastus lateralis. Free-flow of joint fluid confirms penetration into the hip joint. As with the deep gluteal tendon, stay sutures are placed in each leaf of the incised joint capsule to facilitate retraction and eventual closure of the capsule.

The hip is externally rotated with the patella pointing directly toward the ceiling, and the scalpel is inserted within the joint capsule so the capsule can be filleted from the cranial and ventral margins of the femoral head and neck. Liberal use of retractors and suction can help with visualization of the entire femoral neck. At this stage, it is often helpful to cut the round ligament of the head of the femur with either curved Mayo scissors or a specifically designed round ligament cutter (not shown in video). Elevation and distal reflection of the vastus lateralis origin completely exposes the femoral neck so that a planned osteotomy line, extending from the lesser trochanter distally to the base of the greater trochanter proximally, can be visualized and both bony landmarks preserved. A slightly distal to proximal orientation of the osteotome is preferable to ensure the femoral shaft is not fractured during the osteotomy. A Hohman retractor placed within the joint capsule and proximal to the femoral neck can improve visualization of the proximal aspect of the femoral neck. In this video, a power oscillating sagittal saw is used to perform the osteotomy. The freed femoral head and neck is grasped with bone-holding forceps or a towel clamp to allow careful cutting of the remaining soft tissue attachments using a scalpel or curved scissors. The osteotomy, especially along its margins, is palpated carefully for any sharp edges or points, and a rasp (in this case, a power reciprocating rasp) is used to create a rounded or smooth contour to protect the surrounding soft tissue during ambulation.

The previously placed stay sutures are helpful in bringing the two leaves of the joint capsule into apposition. Achieving anatomic closure of the joint capsule can be challenging; one helpful tip is to preplace each suture but not tie the sutures until all of them have been placed in the joint capsule. This ensures adequate and complete soft tissue interposition between the acetabulum and cut surface of the femur. The end result should translate itself into increased patient comfort during ambulation, preventing painful bone-on-bone contact between the femur and adjacent pelvis. The origin of the vastus lateralis that had been elevated and reflected distally is now sutured (or alternatively, this portion of the vastus lateralis can be sutured to the deep gluteal tendon). The partially tenotomized deep gluteal tendon is reconstructed with several cruciate sutures or a pulley suture pattern. No palpable crepitus should be evident at this point of the procedure when full range of motion of the limb is performed. Closure of the fascia lata, superficial musculature, subcutaneous tissue and skin is routine.

Outcome

The best possible outcome can be achieved with:

• Positive identification and partial tenotomy of the deep gluteal tendon during the surgical approach to the hip

• Elevation of the joint capsule and vastus lateralis for visualization of the junction of the femoral neck and shaft; this will allow excision of the entire femoral neck

• Preservation of the lesser trochanter and proper orientation of the osteotome to prevent fracture of the femoral shaft

• Complete soft tissue interposition using the joint capsule between the acetabulum and osteotomy surface

• Convalescent rehabilitation, which is important to encourage early postoperative limb use

This video was authored by Ross Palmer DVM, DACVS. Other surgical videos, including cadaveric dissection of the anatomy relevant to the FHO procedure, are available through VideoVet.

Surgeon's Corner is intended as a forum for those with specialized expertise to share their approaches to various techniques and procedures. As such, the content reflects one expert's approach and has not been peer reviewed.