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Michael D. McKee, M.D., FRCSC
Associate Professor, Division of Orthopaedics
Department of Surgery, St. Michael's Hospital
University of Toronto
Toronto, ON A vascular necrosis of the femoral head in young adults is a crippling disorder with a poor natural history: numerous studies describe the seemingly inevitable progression of disease that occurs in the patient who presents with hip pain and changes visible on plain radiographs. Corticosteroid use (even short-term), excessive alcohol intake, trauma and hemaglobinopathy are frequently identified as the most common causes, while approximately 10% have no identified etiology1.
Figure 1
Anteroposterior radiograph of a 29-year-old patient with steroid-induced avascular necrosis. There is some mild loss of sphericity of the femoral head. The treatment of avascular necrosis is dependent upon symptomatology, the radiographic stage of the disease and age of the patient. Younger patients, especially with earlier stage disease, are candidates for operative procedures that attempt to salvage the femoral head. While older patients do well, total hip arthroplasty for advanced avascular necrosis has been demonstrated to have higher complication rates and a poorer prognosis in younger patients. At our institution, we have had extensive experience with vascularized fibular grafting (VFG) of the femoral head for avascular necrosis, as described and popularized by Urbaniuk.2
The advantages of vascularized fibular grafting include being able to perform a core decompression of the femoral head, the ability to perform curettage and removal of the osteonecrotic focus, impaction of autogenous cancelleous graft securely in the defect created by removal of the osteonecrotic bone, the structural support provided by the fibular graft, and the addition of vascularized bone and blood supply to the area of osteonecrosis.
 | Figure 2
Follow-up anteroposterior radiograph seven years after vascularized fibular grafting. Some irregularity of the femoral head persists, and the joint space is narrowed, but the patient remains essentially asymptomatic and works full-time. | Since this is a major operative procedure with a long rehabilitation time, patient selection to minimise the potential for an unsuccessful operation is critical. We currently reserve this technique for patients 1) with two millimetres or less of femoral head collapse as measured on plain radiographs, 2) who are 45 years of age or younger (and have a reasonable life expec-tancy), 3) have had withdrawal of the etiologic agent (for steroids, at least a decrease to a "maintenance" dose), 4) have no contractures about the hip and 5) have a supple joint. These are general guidelines that may be adjusted somewhat depending on the individual patient.
Our own results closely parallel those of Urbaniuk.3 In our study of the first 63 hips treated with VFG for this condition at our institution, the success rate (defined as no further surgery) was 73% at a mean of 50 months postoperatively (Figures 1 and 2). The mean Harris hip score improved from 57 preoperatively to 84 postoperatively (p=0.001). This study showed that success was very dependant on the initial stage of the disease, and that the more advanced stages fared worse. Our experience now extends to over 300 cases, and as we have refined our indications to exclude these advanced cases, our success rate has improved significantly.
Complications of this procedure requiring re-operation are unusual, the most common being contracture of the flexor hallucis longus muscle/tendon requiring release. In a separate study examining the effect of the fibular harvest on the patient, we found that the patients in our series are, for the most part, satisfied with the appearance, function and lack of discomfort of the lower leg following fibular transfer4. Conversion of a failed VFG to total hip arthroplasty requires special attention to remove the fibular strut, but has little effect on long-term outcome.
At the present time, the use of a trabecular metal "AVN rod" has a number of attractive theoretical advantages, including no donor site morbidity, improved rehabilitation, structural support of the femoral head and the potential for "osseointegration" of this biologically friendly material. However, although clinical trials are underway, there is no data to support this device for general use at the present time.
In conclusion, vascularized fibular grafting for avascular necrosis of the hip has satisfactory results in carefully selected patients. It has a proven clinical record, low donor site morbidity, preserves the patient's own femoral head and can be converted to total hip arthroplasty if failure occurs. It remains our procedure of choice for avascular necrosis of the femoral head in appropriately selected patients.
References
- McKee M.D., Waddell J.P., Kudo P.A., Schemitsch E.H., Richards R.R. Osteonecrosis of the femoral head in men following short-course corticosteroid therapy: A report of 15 cases. Canadian Med Assoc J, Jan 23, 2001;164(2).
- Urbaniak J.R., Coogan P.G., Gunneson E.B., Nunley J.A. Treatment of osteonecrosis of the femoral head with free vascularized fibular grafting. J Bone Joint Surg Vol.77-A, No.5, May 1995 p 681-694.
- Louie B.E., McKee M.D., Richards R.R., Mahoney J.L., Waddell J.P., Beaton D.E., Schemitsch E.H., Yoo D. Treatment of osteonecrosis of the femoral head by free vascularized fibular grafting. Can. J. Surg, Vol 42, No.4, 274-283, 1999.
- Tang C.L., Mahoney J.L., McKee M.D., Richards R.R., Waddell J.P., Louie B., Yoo D. Donor site morbidity following vascularized fibular grafting. Microsurgery 18:383-386, 1998.
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