The Journal of Bone and Joint Surgery

Image Quiz

Part 2: Treatment Alternatives for Osteonecrosis of the Femoral Head
(continued)

Fig. 3-a

Fig. 3-b

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Figures 3-a and 3-b show lesions that would be appropriately treated with bone-grafting. On the plain radiograph (Fig. 3-a), the femoral head demonstrates typical signs of osteonecrosis (cystic and sclerotic changes) with minimal head depression (< 2 mm). The MRI scan (Fig. 3-b) is a T1-weighted image showing a large lesion involving > 30% of the femoral head. If the cartilage of the femoral head appears to be damaged on the MRI examination or is found intraoperatively to be damaged, another procedure must be attempted. Intraoperative visualization and palpation of the acetabulum are also very important in determining the selection of treatment options.

The indications for bone grafting are controversial. Some surgeons will attempt to preserve the natural femoral head with the initial surgery, while others will choose a total hip arthroplasty as the primary treatment option.

Fig. 4

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Nonvascularized Bone-Grafting: The goals of this procedure are to maintain articular congruity, to prevent collapse, and to provide a framework for the remodeling of subchondral bone^1,2,5,6. Results are more favorable in patients with avascular necrosis without femoral head collapse or in patients with minimal head depression (< 2 mm). The necrotic bone is removed through the core tract, the femoral neck ("the light bulb procedure")⁵, or the femoral neck-head junction (the trapdoor procedure)⁶. The remaining cavity can be filled with cancellous and/or cortical bone or bone-graft substitutes. Figure 4 is a postoperative radiograph made after nonvascularized bone-grafting.

Vascularized Bone-Grafting: The rationale for use of a vascularized fibular graft is that it decompresses the lesion, provides structural support, and theoretically increases vascularity, thus enhancing healing^7,8.

Fig. 5

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Figure 5 is a postoperative radiograph made after vascularized fibular bone-grafting. As with nonvascularized bone-grafting, the results are more favorable in patients with avascular necrosis prior to collapse of the femoral head or in patients with minimal head depression (< 2 mm). Disadvantages of this procedure include donor-site morbidity, as a result of the fibular graft harvest, and the inability of the surgeon to inspect the cartilage of the acetabulum or the femoral head. The five-year survivorship of this surgical intervention is increased when it is performed at the earlier osteonecrotic stages.

Osteotomy: The principle of osteotomy as a treatment for osteonecrosis is to displace the osteonecrotic segment of the femoral head from the principal weight-bearing area to an area of decreased weight bearing^1,2,9,10.

Fig. 6-a

Fig. 6-b

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Figures 6-a and 6-b are radiographs showing a medium-sized osteonecrotic lesion and the varus osteotomy performed to treat it, at six years postoperatively. Best results have been obtained in small or medium-sized lesions (having < 30% femoral head involvement and a combined necrotic angle of < 200°) and in early Ficat and Arlet stage-III hips. Two categories of osteotomy are performed: valgus or varus and intertrochanteric. These procedures are technically difficult and the results are variable. Total hip arthroplasty is possible after an osteotomy; however, the proximal femoral anatomy may be distorted, thus making the second procedure more difficult.

Limited Femoral Resurfacing: With the younger patient population associated with osteonecrosis, total hip arthroplasty may not be the optimum solution. In resurfacing, the damaged cartilage of the femoral head is removed and bone stock is preserved, as is the intact acetabular cartilage. Although variable success rates have been achieved in the past^11-13, recent reports have shown encouraging results for this procedure with use of the newer prosthetic designs^14-18. Some reports^2,16 show that resurfacing may preclude or delay total hip arthroplasty for ten years or longer. One study¹⁹ of thirty limited femoral head resurfacing procedures showed a 90% clinical success rate (twenty seven hips had a Harris Hip Score >80 points) at a mean of eighty-four months, but 20% of the patients (six of thirty) had persistent groin pain. The role of limited femoral resurfacing in the treatment of osteonecrosis of the femoral head is controversial. While some surgeons believe that this is a valuable procedure for select advanced lesions (those having a combined necrotic angle of > 200°, femoral head involvement > 30%, intact acetabular cartilage, and minimal joint-space narrowing), others would recommend a total hip arthroplasty in this setting.

Fig. 7-a

Fig. 7-b

Fig. 7-c

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Figure 7 shows: (a) a radiograph of a femoral head depressed because of osteonecrosis,(b) a T2-weighted magnetic resonance imaging scan (MRI) demonstrating collapse of a large lesion, and (c) a postoperative radiograph made after limited femoral head resurfacing.

Total Hip Arthroplasty: For patients with advanced osteonecrosis, in whom both the femoral head and the acetabular cartilage are damaged, total hip arthroplasty is the only treatment option^20,21.

Fig. 8-a

Fig. 8-b

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Figure 8-a is a preoperative radiograph showing a massively collapsed femoral head and damaged acetabulum, the effects of osteonecrosis, and Figure 8-b is a postoperative radiograph of the total hip arthroplasty performed in the same patient. In the elderly, it is also an appropriate treatment for less advanced lesions. This procedure, however, has worse outcomes in patients with osteonecrosis than it does in patients with other diagnoses. Therefore, some surgeons believe that the procedures described previously, which attempt to preserve host bone and cartilage, are indicated, when appropriate, before a total hip arthroplasty is performed.

Recent Advances: To improve the results of total hip arthroplasty in patients who have osteonecrosis of the femoral head, different bearing surfaces are being used: metal-on-metal, ceramic-on-ceramic, and highly cross-linked polyethylenes. These options may increase the durability and decrease the failure rate of total hip arthroplasty in this patient population, but their success can only be assessed through longer-term follow-up studies.

The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. The Orthopaedic Research and Education Foundation and commercial entities (Merck, Stryker Howmedica Osteonics, Wright Medical Technology, Genetics Institute, Pharmacia, Nutramax, and Exactech) paid or directed, or agreed to pay or direct, benefits to a research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.

References:

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2. Mont MA, Jones LC, Sotereanos DG, Amstutz HC, Hungerford DS. Understanding and treating osteonecrosis of the femoral head. Instr Course Lect. 2000;49:169-85.
3. Fairbank AC, Bhatia D, Jinnah RH, Hungerford DS. Long-term results of core decompression for ischaemic necrosis of the femoral head. J Bone Joint Surg Br. 1995;77:42-9.
4. Mont MA, Carbone JJ, Fairbank AC. Core decompression versus nonoperative management for osteonecrosis of the hip. Clin Orthop. 1996;324:169-78.
5. Rosenwasser MP, Garino JP, Kiernan HA, Michelsen CB. Long term followup of thorough debridement and cancellous bone grafting of the femoral head for avascular necrosis. Clin Orthop. 1994;306:17-27.
6. Mont MA, Einhorn TA, Sponseller PD, Hungerford DS. The trapdoor procedure using autogenous cortical and cancellous bone grafts for osteonecrosis of the femoral head. J Bone Joint Surg Br. 1998;80:56-62.
7. Sotereanos DG, Plakseychuk AY, Rubash HE. Free vascularized fibula grafting for the treatment of osteonecrosis of the femoral head. Clin Orthop. 1997;344:243-56.
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17. Nelson CL, Walz BH, Gruenwald JM. Resurfacing of only the femoral head for osteonecrosis. Long-term follow-up study. J Arthroplasty. 1997;12:736-40.
18. Amstutz HC, Grigoris P, Safran MR, Grecula MJ, Campbell PA, Schmalzried TP. Precision-fit surface hemiarthroplasty for femoral head osteonecrosis. Long-term results. J Bone Joint Surg Br. 1994;76:423-7.
19. Mont MA, Rajadhyaksha AD, Hungerford DS. Outcomes of limited femoral head resurfacing as compared to total hip arthroplasty for osteonecrosis. J Arthroplasty. [Accepted for publication in early 2002.]
20. Steinberg ME, Bands RE, Parry S, Hoffman E, Chan T, Hartman KM. Does lesion size affect the outcome in avascular necrosis? Clin Orthop. 1999;367:262-71.
21. Steinberg ME, Hayken GD, Steinberg DR. The "conservative" management of avascular necrosis of the femoral head. In: Bone circulation. Arlet J, Ficat RP, Hungerford DS, editors. Baltimore: Williams and Wilkins; 1984. p 334-7.