Surgery Section - Femoroacetabular Impingement (FAI) Surgery

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Femoroacetabular impingement (FAI), as a diagnostic entity, is a recently recognized condition of the hip that may result from abnormalitiesof the femoral head-neck junction (cam impingement), acetabulum (pincer impingement) or, most commonly, a combination of both (mixed impingement). Labral tears and cartilage damage may develop. FAI may cause pain mainly in the groin area, may limit hip joint motion and may lead to early onset of hip osteoarthritis. Patients who present with this condition are often young adults, especially athletes who have a history of active participation in sports. Patients may present with hip pain that can be diagnosed as FAI by a combination of clinical evaluation, radiographs, and MR arthrography. Although osteoarthritis can be identified with plain film radiographs, articular damage is not always identified with current imaging techniques.

Other terms that may be used for FAI include the following:

• Acetabular rim syndrome
• Acetabular retroversion
• Pistol grip deformity of the proximal femur
• Bone spurs of the hip

Nonsurgical treatments include modification of activities and avoidance of specific movements that elicit symptoms and non-steroidal anti-inflammatory drugs. Intra-articular steroid injections and physical therapy with hip strengthening exercises may reduce symptoms. Hip stretching exercises such as yoga usually make symptoms worse.

• Hip decompression
• Joint preserving surgery
• Resection osteoplasty
• Osteotomy (periacetabular for reorientation of a retroverted acetabulum, trochanteric or intertrochanteric)
• Hip debridement

The outcomes of FAI surgery include short-, mid-, and long-term results.  Since this condition has been recognized for less than a decade, long-term outcomes of FAI surgery are not known. Since neither the natural history of femoroacetabular impingement (FAI) nor the effect of osteochondroplasty on the development and progression of osteoarthritis is known, this medical policy focuses on surgery for the purpose of relieving pain and improving functional limitations caused by FAI morphology.

Note:  The procedure may be done arthroscopically or as an open procedure based on the evaluation and recommendation of the treating surgeon.  It is preferable that any surgeon performing a surgical procedure have current, appropriate experience applicable to that procedure. Surgical treatment of FAI should be performed only in centers experienced in treating this condition and staffed by surgeons who have attended courses in FAI surgery, particularly for arthroscopic surgery, who perform at least ten FAI surgeries per year, and who are able to perform other hip surgeries that may be necessary during FAI surgery (e.g., labral debridement and repair, osteoplasty, synovectomy). Because of the differing benefits and risks of open and arthroscopic approaches, patients should make an informed choice between the procedures.

Policy/Criteria

Note:  Femoroacetabular impingement (FAI) should not be confused with acetabular dysplasia, considered a part of developmental dysplasia of the hip (DDH), formerly described as congenital hip dislocation.

1. Open or arthroscopic treatment of femoroacetabular impingement (FAI) may be medically necessary when all of the following criteria are met:
   1. Age
      1. Adolescent patients should be skeletally mature with documented closure of growth plates
      2. Adult patients should be young enough to be considered inappropriate candidates for total hip arthroplasty or other reconstructive hip surgery (e.g., younger than 55 years).
   2. Symptoms
      1. Moderate-to-severe hip pain that is worsened by flexion activities (e.g., squatting or prolonged sitting) that significantly limits activities
      2. Unresponsive to conservative therapy for at least three months, or conservative therapy is contraindicated (e.g., history of falls due to mechanical instability of hip joint). Conservative therapy for FAI should include:
         1. Activity modification including avoidance of hip stretching activities (e.g., yoga)
         2. Restriction of athletic pursuits
         3. Avoidance of symptomatic motion. 
      3. Positive impingement sign on clinical examination (i.e., pain elicited with 90 degrees of flexion and internal rotation and adduction of the femur)
   3. Imaging
      1. Morphology indicative of cam-type or pincer-type FAI, e.g., pistol-grip deformity, femoral head-neck offset with an alpha angle greater than 50 degrees, a positive wall sign, acetabular retroversion (overcoverage with crossover sign), coxa profunda or protrusion, or damage of the acetabular rim
      2. High probability of a causal association between the FAI morphology and damage, e.g., a pistol-grip deformity with a tear of the acetabular labrum and articular cartilage damage in the anterosuperior quadrant
      3. No evidence of advanced osteoarthritis, defined as Tonnis grade II or III, or joint space of less than 2 mm, except when there is mechanical instability
      4. No evidence of severe (Outerbridge grade IV) chondral damage.
2. Surgical treatment of FAI is considered investigational for all other indications.

Position Summary

The primary outcomes of surgical correction of femoroacetabular impingement (FAI) morphology are symptom management and joint preservation.  The impact of FAI surgery must be determined for the following:

• Pain relief and functional improvement
• Delay or prevention of the development and progression of hip osteoarthritis
• Delay or elimination of the need for total hip arthroplasty

There are currently no published randomized controlled trials; therefore, to evaluate the potential benefit of FAI surgery, available evidence was reviewed for the following:

• Evidence that FAI is an etiology of cartilage damage and hip osteoarthritis
• Evidence for benefit of open or arthroscopic osteoplasty on pain and function
• Evidence of specific indications and the appropriate timing for surgical intervention

Natural History of FAI

Evidence on the natural history and long-term effect of treatment is limited due to the relatively recent recognition of this condition. Overall, the retrospective evidence available indicates a relatively strong association between cam-type impingement related to a pistol-grip deformity, labral damage, and the subsequent development of osteoarthritis. (2-6)

The identification of patients with FAI morphology who will progress to osteoarthritis (and perhaps more importantly those who are unlikely to progress) is limited at this time, although some evidence from retrospective studies is beginning to emerge.

• Not all patients with FAI morphology will have FAI pathology
• There is a high association between FAI pathology and idiopathic osteoarthritis, but this may represent a small proportion of the total cases of hip osteoarthritis.
• It is not known whether patients with FAI morphology are more likely to have osteoarthritis than those without FAI morphology.
• It is not known which patients with FAI morphology are most likely to progress to osteoarthritis
• The progression of pincer impingement with damage initially restricted to the labrum may follow a different time course than cam-type impingement.

Effectiveness

Sufficient evidence exists to suggest that surgical correction of FAI morphology with or without labral and articular cartilage repair or debridement may be beneficial for carefully selected patients. (7-15)

• The relationship between FAI morphology and damage to the acetabulum has been established intraoperatively.
• Large prospective case series have consistently reported improvement in symptoms.
• The potential exists for continued and irreparable cartilage damage if FAI pathology is not addressed.
• In cases in which there is a positive impingement test result, anterosuperior labral or acetabular damage identified on MR arthrography and a pistol-grip morphology identified on imaging, there is a very high probability that the acetabular damage is caused by impingement of the femoral head-neck junction against the acetabular rim.
• Repair of the labrum alone can improve symptoms in the short term. It is reasonable to expect that debridement/osteoplasty of the bump or bone spur would reduce continued abrasion in the long term. Some studies, albeit of low quality, support this view.

Current literature suggests that the degree of osteoarthritis at the time of surgery may impact effectiveness of surgical treatment. (14-16)

• Treatment of FAI is most effective in younger patients without osteoarthritis (Tonnis grade 0 or I) or severe cartilage damage.
• In large case series, arthroscopic treatment of FAI in young to middle-age patients without osteoarthritis and showing mild to moderate cartilage damage resulted in 75% to 85% of patients improved.
• Smaller case series suggested that open treatment of FAI in young to middle-age patients with moderate to severe cartilage damage resulted in 50% to 70% of patients improved. Non-union has been reported to occur in 27% of patients following the transection of the great trochanter with hip dislocation.
• There is a high probability that symptoms in patients with osteoarthritis (Tonnis grade II or III, or joint space of less than 2 mm) or severe cartilage damage (Outerbridge grade IV) will not improve following osteoplasty. These patients may require THA for progressing pain within 5 years.

It is unknown whether treatment of FAI will reduce the occurrence of osteoarthritis.

It is unknown whether arthroscopic techniques result in better net health outcomes compared with open techniques when patients are matched for severity of FAI morphology and articular cartilage damage.

It is unknown how any benefits that may be achieved with FAI surgery are affected when highly active patients (e.g., athletes) resume their preoperative level of activity.

Safety

Possible complications of FAI surgery include the following:  Infection; deep vein thrombosis; femoral fracture; cartilage, nerve or vascular damage; loose bodies in the joint; bleeding into the joint; heterotopic ossification; late-onset avascular necrosis of the femoral head.

Outcomes with respect to other safety issues are also unknown:

• The complication and surgical revision rates of surgery for FAI are unknown.  Minimal details related to safety were reported in the available short-term studies, and there are no long-term data currently published.
• It is unknown whether arthroscopic techniques reduce complication rates or the need for additional surgery compared with open techniques.
• The effects of the extended traction required during arthroscopic surgery are unknown.

Clinical Practice Guidelines

There are no evidence-based clinical practice guidelines from U.S. professional associations that recommend this procedure as a treatment option for FAI.

Clinical practice guidelines from the National Institute for Health and Clinical Excellence (NICE), a European professional association, consider the current literature to be inadequate for both open and arthroscopic procedures. (17,18)

Specialist Advisors to NICE highlighted the following points:

• Hip impingement is a relatively recently recognized pathological process.
• There is no long-term efficacy data to prove slowing of osteoarthritis.
• There is a concern that impingement is being overdiagnosed and that some unnecessary surgery may be taking place as a result.
• Surgical techniques continue to evolve.
• The arthroscopic technique is complicated. The procedure and the training of surgeons should only be conducted by expertise in hip arthroscopy in a setting with experienced staff and dedicated equipment and imaging.
• No standardized scores for clinical outcomes evaluation of the arthroscopic technique have yet been developed.

References

1. BlueCross BlueShield Association Medical Policy Reference Manual, Policy No. 7.01.118
2. Beck M, Kalhor M, Leunig M, Ganz R. Hip morphology influences the pattern of damage to the acetabular cartilage: femoroacetabular impingement as a cause of early osteoarthritis of the hip. J Bone Joint Surg Br 2005;87(7):1012-8
3. Bardakos NV, Villar RN. Predictors of progression of osteoarthritis in femoroacetabular impingement: a radiological study with a minimum of ten years follow-up. J Bone Joint Surg Br 2009; 91(2):162-9
4. Tanzer M, Noiseux N. Osseous abnormalities and early osteoarthritis: the role of hip impingement. Clin Orthop Relat Res 2004;(429):170-7
5. Takeyama A, Naito M, Shiramizu K et al. Prevalence of femoroacetabular impingement in Asian patients with osteoarthritis of the hip. Int Orthop 2009 Mar 11. [Epub ahead of print]
6. Kim KC, Hwang DS, Lee CH et al. Influence of femoroacetabular impingement on results of hip arthroscopy in patients with early osteoarthritis. Clin Orthop Relat Res 2007;456:128-32
7. Byrd JW, Jones KS. Arthroscopic femoroplasty in the management of cam-type femoroacetabular impingement. Clin Orthop Relat Res 2009;467(3):739-46
8. Beaulé PE, Le Duff MJ, Zaragoza E. Quality of life following femoral head-neck osteochondroplasty for femoroacetabular impingement. J Bone Joint Surg Am 2007;89(4):773-9
9. Larson CM, Giveans MR. Arthroscopic management of femoroacetabular impingement: early outcomes measures. Arthroscopy 2008;24(5):540-6
10. Murphy S, Tannast M, Kim YJ et al. Debridement of the adult hip for femoroacetabular impingement: indications and preliminary clinical results. Clin Orthop Relat Res 2004;(429):178-81
11. Bardakos NV, Vasconcelos JC, Villar RN. Early outcome of hip arthroscopy for femoroacetabular impingement: the role of femoral osteoplasty in symptomatic improvement. J Bone Joint Surg Br 2008;90(12):1570-5
12. Beck M, Leunig M, Parvizi J et al. Anterior femoroacetabular impingement: part II. Midterm results of surgical treatment. Clin Orthop Relat Res 2004;(418):67-73
13. Peters CL, Erickson JA. Treatment of femoro-acetabular impingement with surgical dislocation and debridement in young adults. J Bone Joint Surg Am 2006;88(8):1735-41
14. Philippon MJ, Briggs KK, Yen YM et al. Outcomes following hip arthroscopy for femoroacetabular impingement with associated chondrolabral dysfunction: minimum two-year follow-up. J Bone Joint Surg Br 2009;91(1):16-23
15. Laude F, Sariali E, Nogier A. Femoroacetabular impingement treatment using arthroscopy and anterior approach. Clin Orthop Relat Res 2009;467(3):747-52
16. Sampson TG. Arthroscopic treatment of femoroacetabular impingement. Techniques in Orthopaedics 2005;20(1):56-62
17. Arthroscopic femoro-acetabular surgery for hip impingement syndrome; Guidance from the National Institute for Health and Clinical Excellence (NICE). Available online at: http://www.nice.org.uk/nicemedia/pdf/ip/IPG213Guidance.pdf (Verified 6/18/09)
18. Open femoro-acetabular surgery for hip impingement syndrome; Guidance from the National Institute for Health and Clinical Excellence (NICE). Available online at: http://www.nice.org.uk/IP243overview (Verified 6/18/09)

Cross References

Total Hip Resurfacing, Regence Medical Policy, Surgery Policy No. 113

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