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MP 7.01.70

Free Vascularized Fibular Grafting for the Treatment of Osteonecrosis of the Hip


Medical Policy
Section
Surgery
Original Policy Date
7/16/99
Last Review Status/Date
Review by consensus/2:2003
Issue
2:2003
Return to Medical Policy Index

Disclaimer

Our medical policies are designed for informational purposes only and are not an authorization, or an explanation of benefits, or a contract.  Receipt of benefits is subject to satisfaction of all terms and conditions of the coverage.  Medical technology is constantly changing, and we reserve the right to review and update our policies periodically.


Description

Avascular necrosis of the hip is a common and disabling condition frequently affecting those younger than age 50. Although it is thought to be related to interruption of the blood supply to the femoral head, the etiology of this vascular abnormality may not be apparent in cases unassociated with trauma or fracture. Stress patterns in the femoral head, increased intramedullary pressure, and fat embolism have been proposed as possible etiologies. Patients with collagen vascular diseases or chronic alcoholism or those who receive steroid therapy are also at increased risk of avascular necrosis. The natural history is progressive, with 85% of patients eventually experiencing collapse of the femoral head within 2 years of diagnosis; 10% or more of all hip replacements are performed for avascular necrosis.

Medical management, consisting primarily of bed rest or non-weight bearing with crutches, is considered ineffective, and a variety of surgical therapies have been investigated in an attempt to halt the progression of the disease and to avoid the need for a hip replacement, which is an unappealing option in patients younger than age 50. Surgical therapies include core decompression to relieve compression caused by interstitial edema and improve vascularity, osteotomies to unload the necrotic segment of the femoral head in an effort to allow healing, and vascularized fibular bone grafting, which attempts to enhance revascularization of the femoral head.

Vascularized fibular bone grafting involves the removal of a segment of fibula with attached vascular pedicle. In a separate surgical field, a core is created in the femoral head by the removal of necrotic bone. Cancellous bone graft is packed into the cavity, followed by transplant of the fibular segment into the remaining cavity. The graft’s vascular pedicle is then anastomosed to the lateral femoral circumflex artery and vein. The rationale for vascularized bone grafting is based on the following hypotheses:

  • Decompression of the femoral head
  • Excision of the sequestrum of necrotic bone that might inhibit revascularization
  • Filling of the defect with osteoinductive cancellous graft and a viable strut (i.e., the fibular graft) to support the subchondral surface and enhance the revascularization process
  • Protection of the healing by a period of limited weight bearing


Policy

Free vascularized fibular grafting may be considered medically necessary in the treatment of avascular necrosis of the femoral head.


Policy Guidelines

There is no specific CPT code for this procedure, but the following series of CPT codes may be used:

27052: arthrotomy with biopsy; hip
 
27641: partial excision bone; fibula
 
20955: bone graft with microvascular anastomosis: fibula
 
20900 or 20902: bone graft, any donor area; minor/small or major/large respectively

Free vascularized fibular grafting is a relatively complex procedure requiring two simultaneous surgical teams with microvascular skills.


Benefit Application

BlueCard/National Account Issues

No applicable information.


Rationale

Vascularized fibular bone grafting is a fairly complex surgical procedure involving 2 surgical fields. The literature consists primarily of single institution case series with outcomes typically focused on Harris hip scores and the need for a subsequent hip replacement. Several large case series of vascularized fibular grafting have reported the following outcomes:

  • Urbaniak and colleagues reported on the results of 103 consecutive hips in 89 patients with avascular necrosis who underwent free vascularized fibular grafting. (1) All patients were followed for a minimum of 5 years. A subsequent hip replacement was performed in 31 of 103 (30%) hips. The average Harris hip scores had improved at the latest follow-up evaluation. The grafting procedure decreased the need for pain medication for 86% of the hips that had not been subsequently treated with an arthroplasty.
  • Sotereanos and colleagues reported on a case series of 88 hips in 65 patients followed up for a minimum of 3 years. (2) At final evaluation 35.2% of hips were rated as excellent according to the Harris hip score, 34.1% were rated as good, 8% were fair, and 22.7% were rated as poor. Almost 23% of hips underwent hip replacement, with the incidence of hip replacement increasing with the severity of the avascular necrosis.
  • Yoo and colleagues reported on the outcomes of 81 hips followed up for a minimum of 3 years. (3) A total of 745 of the hips were rated as excellent by the Harris hip score, 17% were rated as good, 7% were rated as fair, and 2% were rated as poor.

While the above case series show promising results, comparisons with other surgical therapies are important to isolate the contribution of the vascularization. For example, the surgery for vascularized fibular grafts also includes core decompression, and although not as thoroughly studied, other grafting techniques include either nonvascularized autologous or allogeneic cortical grafts to provide a similar strut as the fibular graft. Therefore, the vascularization is the unique component of the overall procedure. Two studies have suggested that vascularized grafts result in improved outcomes compared to core decompression alone. Kane and colleagues reported on a study of 39 hips randomized to receive either a vascularized graft or core decompression. (4) In the core decompression group, 58% underwent hip replacement compared to only 20% in the free vascularized fibular grafting group. Scully and colleagues used statistical analysis to compare the results in 614 hips treated with fibular grafting at one center (Duke University) compared with 98 hips treated with core decompresssion at another center (Brown University). (5) The need for hip replacement was the primary outcome. Only 11% of the 111 hips with Stage II disease eventually had a total hip arthroplasty compared with 35% of the 43 patients with Stage II disease who underwent core decompression. While those undergoing core decompression were, in general, older than those undergoing vascularized grafting, the significant differences persisted even after analytical adjustment for this bias. Similarly the rate of total hip replacement in patients with more severe Stage III disease was significantly lower in those treated with vascularized grafting. Sources of potential bias that were not accounted for include the extent of the involvement of the femoral head.

References:

  1. Urbaniak JR, Coogan PG, Gunneson EB et al. Treatment of osteonecrosis of the femoral head with free vascularized fibular grafting. A long-term follow-up study of one hundred and three hips. J Bone Joint Surg Am 1995; 77(5):681-94.
  2. 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.
  3. Yoo MC, Chung DW, Hahn CS. Free vascularized fibula grafting for the treatment of osteonecrosis of the femoral head. Clin Orthop 1992; 277:128-38.
  4. Kane SM, Ward WA, Jordan LC et al. Vascularized fibular grafting compared with core decompression in the treatment of femoral head osteonecrosis. Orthopedics 1996; 19(10):869-72.
  5. Scully SP, Aaron RK, Urbaniak JR. Survival analysis of hips treated with core decompression or vascularized fibular grafting because of avascular necrosis. J Bone Joint Surg Am 1998; 80(9):1270-5.

Source:

A search of the literature was completed through the MEDLINE database for the period of 1990 through April of 1999. The search strategy focused on the references containing the following words:

Avascular necrosis of the hip
 
Fibular grafting

 

Codes

Number

Description

CPT  27050  Arthrotomy, with biopsy; hip joint 
  20955  Bone graft with microvascular anastomosis: fibula 
  27641  Partial excision bone; fibula 
ICD-9 Diagnosis  733.42  Aseptic necrosis of bone, head and neck of femur 
HCPCS   
Type of Service  Surgery 
Place of Service  Inpatient 


Index

Avascular necrosis of the femoral head; fibular grafting
Fibular grafting; avascular necrosis of the femoral head
Osteonecrosis; femoral head; fibular grafting


Policy History

Date Action Reason
07/16/99 Add to Surgery section New policy
04/15/02 Replace policy Policy reviewed by consensus; new review date
07/17/03 Replace policy Policy reviewed by consensus; no changes in policy


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