Coverage Policy Manual
Policy #: 2009033
Category: Surgery
Initiated: September 2009
Last Review: June 2018
  Femoroacetabular Impingement, Surgical Treatment of

Description:
Femoroacetabular impingement (FAI), a condition that has been recently recognized, is an anatomical mismatch between the head of the femur and the acetabulum resulting in compression of the labrum or articular cartilage during flexion. The mismatch can arise from subtle morphologic alterations in the anatomy or orientation of the ball-and-socket components (for example, a bony prominence at the head-neck junction or acetabular overcoverage) with articular cartilage damage initially occurring from abutment of the femoral neck against the acetabular rim, typically at the anterosuperior aspect of the acetabulum. Although hip joints can posses the morphologic features of FAI without symptoms, FAI may become pathologic with repetitive movement and/or increased force on the hip joint. High-demand activities may also result in pathologic impingement in hips with normal morphology.
 
Two types of impingement, known as cam impingement and pincer impingement, may occur alone or more frequently together. Cam impingement is associated with an asymmetric or nonspherical contour of the head or neck of the femur jamming against the acetabulum, resulting in cartilage damage and delamination (detachment from the subchondral bone). Deformity of the head/neck junction that looks like a pistol grip on radiographs is associated with damage to the anterosuperior area of the acetabulum. Symptomatic cam impingement is found most frequently in young male athletes. Pincer impingement is associated with overcoverage of the acetabulum and pinching of the labrum, with pain more typically beginning in women of middle age. In cases of isolated pincer impingement, the damage may be limited to a narrow strip of the acetabular cartilage. It has been proposed that impingement with damage to the labrum and/or acetabulum is a causative factor in the development of hip osteoarthritis, and that as many as half of cases currently categorized as primary osteoarthritis may have an etiology of FAI.
 
Previously, access to the joint space was limited and treatment consisted primarily of debridement and/or labral reattachment. A technique for hip dislocation with open osteochondroplasty that preserved the femoral blood supply was reported by Ganz and colleagues in 2001. Visualization of the entire joint with this procedure led to the identification and acceptance of FAI as an etiology of cartilage damage (the association between abnormal femoral head/neck morphology and early-age-onset osteoarthritis had been described earlier by others) and the possibility of correcting the abnormal femoroacetabular morphology. Open osteochondroplasty of bony abnormalities and treatment of the symptomatic cartilage defect is considered the gold standard for complex bony abnormalities. However, open osteochondroplasty is invasive, requiring transection of the greater trochanter (separation of the femoral head from the femoral shaft) and dislocation of the hip joint to provide full access to the femoral head and acetabulum. In addition to the general adverse effects of open surgical procedures, open osteochondroplasty with dislocation has been associated with non-union, and neurologic and soft tissue lesions. Less invasive hip arthroscopy and an arthroscopy-assisted mini-approach were adapted from the open approach by 2004. Arthroscopy requires specially designed instruments and is considered to be more technically difficult due to reduced visibility and limited access to the joint space. Advanced imaging techniques, including computed tomography and fluoroscopy, have been utilized to improve visualization of the 3-dimensional head/neck morphology during arthroscopy.
 
The recognition and treatment of FAI has also brought attention to the possibility of cam-type FAI after slipped capital femoral epiphysis (SCFE). The standard treatment for SCFE is stabilization across the physis by in-situ pinning, although it is not uncommon for patients with SCFE to develop premature osteoarthritis requiring total hip arthroplasty within 20 years. Treatments being evaluated for pediatric patients with SCFE-related FAI include osteoplasty without dislocation, or with the open dislocation technique described by Ganz. The Ganz technique (capital realignment with open dislocation) is technically demanding with a steep learning curve and a high risk of complications. Therefore, early treatment to decrease impingement must be weighed against increased risk for adverse events including avascular necrosis in patients with SCFE.
 
It is known that surgical treatment of FAI pathology is less effective for pain reduction in patients with late stage osteoarthritis. In addition, delay in the surgical correction of bony abnormalities may lead to disease progression to the point where joint preservation is no longer appropriate. It is believed that osteoplasty of the impinging bone is needed to protect the cartilage from further damage and preserve the natural joint. If FAI morphology is shown to be an etiology of osteoarthritis, a future strategy to reduce the occurrence of idiopathic hip osteoarthritis could be early recognition and treatment of FAI before cartilage damage occurs.
 
Effective in 2011, there are 3 specific CPT codes for these procedures when performed arthroscopically:
 
29914: Arthroscopy, hip, surgical; with femoroplasty (i.e., treatment of cam lesion)
29915: Arthroscopy, hip, surgical; with acetabuloplasty (i.e., treatment of pincer lesion)
29916: Arthroscopy, hip, surgical; with labral repair
 
There are no specific CPT codes for the open treatment of FAI. The procedure might be coded using code 27299 (unlisted procedure, pelvis or hip joint).
 
Prior to 2011, there were no specific CPT codes for these procedures. The procedures would likely have been coded using unlisted CPT codes such as code 27299 (unlisted procedure, pelvis or hip joint) or code 29999 (unlisted procedure, arthroscopy). Codes such as 29862 (arthroscopy, hip, surgical; with debridement/shaving of articular cartilage [chondroplasty], abrasion arthroplasty, and/or resection of labrum) and 27151 (osteotomy, iliac, acetabular or innominate bone; with femoral osteotomy) might also have been used.
  
There is also no specific ICD-9-CM diagnosis code for FAI. It might be coded using an unspecified code such as 719.95 (unspecified disorder of joint, pelvic region and thigh).
 
Treatment of FAI should be restricted to centers experienced in treating this condition and staffed by surgeons adequately trained in techniques addressing FAI. Because of the differing benefits and risks of open and arthroscopic approaches, patients should make an informed choice between the procedures.
  

Policy/
Coverage:
Effective April 2013
Open or arthroscopic treatment of femoroacetabular impingement meets primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes when all of the following conditions have been met:
 
Age
    • Adolescent patients should be skeletally mature with documented closure or near closure of growth plates (e.g., 15 years or older).
 
Symptoms
    • Moderate-to-severe hip pain that is worsened by flexion activities (e.g., squatting or prolonged sitting) that significantly limits activities; AND
    • Unresponsive to conservative therapy for at least 3 months (including activity modifications, restriction of athletic pursuits and avoidance of symptomatic motion); AND
    • Positive impingement sign on clinical examination (pain elicited with 90 degrees of flexion and internal rotation and adduction of the femur).
 
Imaging
    • Morphology indicative of cam 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; AND
    • 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; AND
    • No evidence of advanced osteoarthritis, defined as Tonnis grade II or III, or joint space of less than 2 mm; AND
    • No evidence of severe (Outerbridge grade IV) chondral damage.
 
Treatment of FAI in all other situations does not meet primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes.
 
For contracts without Primary Coverage Criteria, treatment of FAI in all other situations is considered investigational.  Investigational services are exclusions in the member benefit certificate of coverage.
 
Effective September 2009 through May 2013
Open or arthroscopic treatment of femoroacetabular impingement meets primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes when all of the following conditions have been met:
 
Age
    • Adolescent patients should be skeletally mature with documented closure of growth plates (e.g., 15 years or older). Adult patients should be too young to be considered an appropriate candidate for total hip arthroplasty or other reconstructive hip surgery (e.g., younger than 55 years).
 
Symptoms
    • Moderate-to-severe hip pain that is worsened by flexion activities (e.g., squatting or prolonged sitting) that significantly limits activities; AND
    • Unresponsive to conservative therapy for at least 3 months (including activity modifications, restriction of athletic pursuits and avoidance of symptomatic motion); AND
    • Positive impingement sign on clinical examination (pain elicited with 90 degrees of flexion and internal rotation and adduction of the femur).
 
Imaging
    • Morphology indicative of cam 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; AND
    • 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; AND
    • No evidence of advanced osteoarthritis, defined as Tonnis grade II or III, or joint space of less than 2 mm; AND
    • No evidence of severe (Outerbridge grade IV) chondral damage.
 
Treatment of FAI in all other situations does not meet primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes.
 
For contracts without Primary Coverage Criteria, treatment of FAI in all other situations is considered investigational.  Investigational services are exclusions in the member benefit certificate of coverage.
 

Rationale:
A literature search using MEDLINE was performed through March 2009. The key issue for this policy is whether correction of femoroacetabular impingement (FAI) morphology with open or arthroscopic osteoplasty alters the development of symptomatic cartilage damage and hip osteoarthritis. Given the relatively recent recognition of FAI and development of interventional procedures, neither the natural history of FAI nor the effect of osteochondroplasty on the development of osteoarthritis is known. No randomized controlled trials were identified. Therefore, to evaluate the potential benefit of FAI with the evidence available at this time, studies were 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 in patients with FAI pathology. If there is benefit, what are the specific indications and the appropriate timing for surgical intervention?
 
Beck and colleagues reported results of a study of 26 patients with pure pistol-grip deformity and 16 patients with isolated coxa profunda who were identified from 302 hips treated for intra-articular pathology between 1996 and 2001. Only hips with minor radiological changes, with narrowing or osteophytes equivalent to an osteoarthrosis grade less than one according to the classification of Tonnis, were included. Excluded were hips with traumatic or post-traumatic conditions (n=37), avascular necrosis (n=14), and hips that had underdone previous surgery (n=7). Patients with incomplete or inadequate preoperative radiographs were also excluded. For the 26 hips that met the inclusion/exclusion criteria and showed isolated cam impingement on preoperative radiographs, all showed acetabular cartilage damage in the anterosuperior area of the acetabulum with separation between the acetabular cartilage and the labrum. In the 16 hips with isolated pincer impingement, the damage was located more circumferentially, usually including only a narrow strip of the acetabular cartilage. The report illustrated that in carefully selected patients with early stage osteoarthritis and well-defined hip configurations, a strong association exists between specific hip morphology and the pattern of cartilage damage. The intent of the study was “to obtain unequivocal data” on the starting point of joint degeneration with FAI; damage in patients with more complex morphology was not described.
 
Baradakos and Villar retrospectively examined progression of osteoarthritis of 43 patients (43 hips) under 55 years of age with a history of symptomatic idiopathic arthritis, first seen no later than 1997, who exhibited pistol-grip deformity of the femur and mild to moderate osteoarthritis (Tonnis grade 1 or 2) at baseline (Bardakos, 2009). Radiographs taken at least 10 years apart showed progression of osteoarthritis in two-thirds of the patients, with 12 receiving hip replacement or resurfacing after more than 10 years. Logistic regression analysis showed the medial proximal femoral angle and the posterior wall sign as the only significant independent predictors for progression of osteoarthritis in this small sample. A reduction of one degree in the medial proximal angle increased the odds of the osteoarthritis progressing by 21 times, while osteoarthritis in a hip with a positive posterior wall sign (the center of the femoral head located lateral to the outline of the of the posterior acetabular rim) was 10 times more likely to progress than a hip that had a negative posterior wall sign. Of note, one-third of the patients with a pistol-grip deformity did not progress rapidly within the assessment period.
 
In another study, Tanzer and Noiseaux reported that of 38 consecutive patients who were treated arthroscopically and who had a labral tear, 97% were found to have a pistol-grip deformity on preoperative radiographs (Tanzer, 2004).  These authors also reported that in 200 consecutive patients (200 hips) having primary total hip arthroplasty, the underlying etiology of patients’ arthritis was determined by their history and radiographic findings. Anteroposterior pelvis, lateral, and frog lateral hip radiographs were evaluated for abnormalities of the femur and/or acetabulum. All patients without a history or radiographic evidence of underlying hip disease were given the diagnosis of idiopathic hip arthritis. From the 125 cases diagnosed as idiopathic arthritis, 100% exhibited a pistol-grip deformity. Radiographs of the contralateral limb showed that 31% of patients had a healthy hip without a deformity or evidence of osteoarthritis, 14% had a deformity without evidence of arthritis, and 55% had a pistol-grip deformity and radiographic evidence of arthritis. A pistol-grip deformity was associated with arthritis later in life.
 
A 2009 study from Asia reviewed records of 843 consecutive patients (978 hips) who underwent primary surgery for osteoarthritis or other diseases of the hip to determine the prevalence of FAI in this population (Takeyama, 2009).  Twenty-six patients (32 hips) were excluded due to insufficient radiographs or records, resulting in a study population of 817 patients (946 hips). The average age at the time of surgery was 54.8 years (range of 12–92 years). All of the patients were Asian. The majority of patients (73%) were diagnosed with osteoarthritis secondary to developmental dysplasia of the hip, another 12% had idiopathic osteonecrosis, and 1.7% had Legg-Calve-Perthes disease. Only 17 patients (1.8%) were considered to have had primary osteoarthritis. Of these, 6 patients (average age, 63 years; range, 32-79) were determined to have FAI from preoperative radiographs, resulting in a possible etiology of FAI for 0.6% of the total population undergoing surgery for osteoarthritis and 35% in the population with primary osteoarthritis.
 
Kim et al reviewed outcomes of 43 patients (mean age, 40 years; range, 18-68 years) who had labral tears and early osteoarthritis (Tonnis grade 0 to 1, average Japanese Orthopedic Association [JOA] scores of less than 1) and symptoms lasting 3 months or more who had been treated with debridement (Kim, 2007).  At an average 50 months’ follow-up (12–96 months), 74% of patients had improved, with 11 showing no improvement. Blinded evaluation of preoperative radiographs and MR arthrograms indicated that 42% of patients had FAI. When treated only with debridement, patients were less likely to improve if early stage osteoarthritis or FAI was present at the time of surgery. For example, on the JOA scale where 0 = severe pain to 3 = no pain, patients without either FAI or osteoarthritis scored 2.6 at follow-up, while patients with FAI scored 1.83 and those with both FAI and osteoarthritis scored 1.67.
 
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. 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.
 
Treatment of FAI with Arthroscopic or Open Approaches
 
Technology Assessments and Systematic Reviews
In 2006, United Kingdom’s National Institute for Health and Clinical Excellence (NICE) conducted a rapid review of the literature on surgery for femoroacetabular impingement, which included 4 case series and a single non-randomized controlled trial on the open approach.  Specialist advisers’ opinions were included in the assessment, which concluded that there was a lack of evidence to determine whether the procedure successfully slows the rate of progression to osteoarthritis, but that efficacy may be influenced by the degree of pre-existing arthritis or degenerative changes before the intervention. Due to the paucity of data, guidance on the arthroscopic approach could not be issued at that time. In 2007, NICE issued guidance on both open and arthroscopic femoroacetabular surgery for hip impingement syndrome, concluding that current evidence on the safety and efficacy was not adequate for the procedure to be used without special arrangements for consent and for audit or research.
 
Bedi and colleagues performed a systematic review of the literature on labral tears and FAI, with a literature search conducted in May 2008 (Bedi, 2008).  Level I, II, III, or IV study designs were included if the patient population had a labral tear and/or FAI as the major diagnosis. Patients with severe pre-existing osteoarthritis or acetabular dysplasia were excluded. Of the 19 articles included, only 1 met the criteria for level III basis of evidence. The studies reviewed suggested that 65% to 85% of patients will be satisfied with their outcome at a mean of 40 months after surgery. All series reported an increased incidence of failure among patients with substantial pre-existing osteoarthritis. The authors concluded that the quality of literature reporting outcomes of surgical intervention for labral tears and FAI is limited. The larger case series, including those published after the literature search for the systematic review by Bedi et al are described below.
 
Primary Literature
 
Arthroscopic Approach
The March 2009 literature review identified 4 prospective/consecutive case series with at least 100 patients/hips and 1 controlled cohort study. A 2005 report by Sampson that described results from 156 patients was also identified (Sampson, 2005).  However, this retrospective review was primarily a description of the newly developed arthroscopic procedure with preliminary results. The age range of the patients was 14 to 73 years, with symptoms ranging from 3 months to 73 years, although the majority of patients were noted to be in their 20s to 30s. One patient had a pathological fracture and 3 patients converted to total hip arthroplasty (THA) by follow-up of up to 22 months. No other complications were noted. Greater cartilage damage (i.e., greater than grade III chondromalacia or delamination defects) were associated with poorer outcomes and/or longer recovery times. The damage to the articular surfaces observed at arthroscopy had often been undetected by preoperative imaging studies.
 
The largest prospective series was by Byrd and colleagues, who provided a brief report on 200 patients (207 hips) from a consecutive group of 220 patients (227 hips) who had been treated with arthroscopy for impingement in 2004-2007 (Byrd, 2009).  Included were 163 hips with cam-type impingement only and 44 hips with combined cam and pincer-type impingement. Twenty hips with pincer impingement only were excluded. The average age of the patients was 33 (range not reported), with symptoms averaging 32 months and no sign of advanced osteoarthritis. There was 100% follow-up of the 207 hips at a minimum of 12 months. At an average of 16 months (range, 12-24 months) after treatment, patients showed an average 20-point improvement (-17 to 60) on the 91-point modified Harris Hip Score (MHHS). Eighty-three percent of patients were considered to be improved by the procedure. One patient (0.5%) required THA within the follow-up period, and 3 patients (1.5%) required revisions for pain.
 
Phillipon et al reported 2.3 year follow-up (range, 2-2.9 years) on 100 of 209 prospectively enrolled consecutive patients who underwent hip arthroscopy for disabling pain (Philippon, 2009).  Patients were included in the study report (n=122) if they underwent arthroscopic treatment for FAI and chondrolabral dysfunction, and did not have bilateral hip arthroscopy, avascular necrosis, or previous surgery. Ten patients did not complete the follow-up questionnaire and were excluded and 12 were lost to follow-up. Of the 100 patients available for follow-up, 90 (90%) improved from an average score of 58 to 84 on the MHHS, and 10 (10%) required THA at a mean of 16 months. Patients with a joint space of less than 2 mm were 39 times more likely to progress to THA.
 
Larson and Giveans reported 10-month follow-up (3 months to 3 years) from a consecutive series of 96 patients (100 hips) who presented with FAI (typically with activity-related groin pain and pain with prolonged sitting) between 2004 and 2007 (Larson, 2008). Preoperative and intraoperative radiographs revealed Tonnis grade 0 to II osteoarthritis with cam impingement in 17 hips, pincer impingement in 28, and a combination of both in 55 hips. The average age was 35 (range, 16-64 years). Following FAI treatment, the impingement test was reported to be better in 86% of patients, with good to excellent results in 75% of patients. Three patients (3%) required THA, and 6 had heterotopic bone formation. Visual analogue scale (VAS) scores for pain improved from 6.7 at baseline to 1.9 at the 3-month to 3-year follow-up. Scores on the SF-12 improved from 60 to 78.
 
A mixed open/arthroscopic approach for treatment of FAI was reported by Laude et al in 97 patients (100 hips) (Laude, 2009).  This technique allows direct visualization of the anterior femoral head-neck junction without dislocation. All patients had a positive impingement test (pain reproduced in flexion, adduction, and internal rotation). All patients had MR arthrography or CT arthrography to analyze the labrum for tears. Nine patients had prior surgery and 3 patients had Tonnis grade 2 osteoarthritis. Thirty patients had grade 1 osteoarthritis. The average age of the patients was 33 (16–56 years old). Ninety-one (94%) were available for follow-up at an average 58 months (range, 29–104 months). Scores on the nonarthritic hip score (NAHS) increased from 55 at baseline to 84 at the last follow-up. One patient had a femoral neck fracture 3 weeks postoperatively, and 13 (14%) required revision due to persistent pain. In 8 of these patients, the damaged part of the labrum was removed and in 6 patients, osteochondroplasty of the head was performed to improve the groove at the head-neck junction. Another patient had heterotopic ossification. Eleven hips (12%) required THA at a mean of 40 months (range, 5–75 months). In the THA group, the acetabular lesions were deeper (10.9 mm vs. 6 mm) and a higher percentage of Beck grade 5 was found (54% vs. 7%). The best results were observed in patients younger than 40 years with a Tonnis grade of 0.
 
Bardakos and colleagues compared results from 24 patients treated with osteochondroplasty for cam impingement (after 2004) with 47 patients who showed cam impingement but had only the labrum repaired (between 2000 and 2004) (Bardakos, 2008).  The cohorts were matched for age (27–46 years) and for follow-up of 1 year. The number of patients who did not meet the selection criteria was not reported. There was a trend (p=0.11) for improved MHHS outcomes (excellent, good, fair, poor) in patients who were treated for impingement in addition to labral repair in this small study. Post hoc analysis of the percentage of patients in the excellent/good category showed significant improvement for the FAI-treated patients over historical controls (83% vs. 60%, p = 0.043). Results of this study should be interpreted cautiously due to multiple potential sources of bias, including selection bias, limited follow-up, and the small sample size.
 
Open Approach
Seven case series of patients with FAI treated with the open approach and dislocation were identified in the systematic review by Bedi et al (Bedi, 2008).  Two studies reported on 5 patients and 5 studies reported results from 19 to 52 patients, with follow-up ranging from 24 to 60 months. The 5 studies are briefly described here.
 
Beck et al reported outcomes from 19 patients (average age, 36,years; range, 21–52) of 22 who had been selected from their database with confirmed clinical, radiographic, and MR-arthrography diagnosis of FAI, had been treated with surgical dislocation of the hip, and had at least 4 years of follow-up (Beck, 2004).  Three patients were excluded based on a history of prior intra-articular surgery of the involved hip. Of the remaining 19, all had labral damage and 18 had acetabular damage. By 4 to 5 years’ follow-up, 5 patients (26%) had undergone THA, with the failures associated with cartilage damage. Thirteen patients (68%) were reported to have had good to excellent outcomes.
 
Another study selected 52 of 141 consecutive patients to compare the effect of reattaching or removing the labrum during treatment for FAI (Espinosa, 2006).  Patients were selected for age (20–40 years) and no prior surgery; all had preoperative evidence of acetabular damage. Patients were excluded from the study because of incomplete clinical or radiographic documentation (n = 48), open growth plates (n = 4), age of greater than 40 years (n = 29), previous hip surgery (n = 7), or participation in professional athletic activity (n = 1). Independent evaluations of 2-year follow-up indicated improved Merle d’Aubigne scores for both groups, from a baseline of 12 to 15 in the group in which the labrum was resected and from 12 to 17 in the group where the labrum was reattached. The study also found a reduction in progression to osteoarthritis if the labrum was reattached.
 
Peters et al reported on 29 patients (30 hips) in a prospective protocol with minimum 2-years’ follow-up (Peters, 2006).  The specific diagnoses were primary femoroacetabular impingement in 25 patients (26 hips), Legg-Calve-Perthes disease (n = 3), and slipped capital femoral epiphysis (n = 1). The average age of the patients was 31 years (range, 16–51 years). Twenty-nine of the 30 hips had either cam-type impingement (n = 14), or mixed cam and pincer-type impingement (n = 15). Eighteen hips were reported to have had severe cartilage damage that was not seen on MR arthrography. The Harris Hip score improved from 70 at baseline to 87 at an average 32-months’ follow-up. No progression to osteoarthritis was observed in 68% of patients. There was non-union in 8 hips (27%), 5 hips (17%) were expected to convert to THA due to progressive pain, and 4 (13%) had progression to osteoarthritis. Radiographic signs of progression of osteoarthritis and clinical failure requiring conversion to THA were seen only in patients with severe damage to the acetabular-articular cartilage. Two additional retrospective studies (n = 23 and 34) that included patients with severe cartilage damage reported that 50% to 70% of patients improved and 30% to 50% failed (either no improvement or underwent subsequent THA) following open osteochondroplasty with dislocation (Beaulé, 2007) (Murphy, 2004).  
 
Summary
Four prospective/consecutive case series with over 100 hips/patients treated for FAI have been published in the last year. These studies show a 20-point improvement on the MHHS at short to mid-term follow-up, indicating a change from marked pain with a serious limitation of activities pre-operatively to mild pain after treatment, or from moderate pain with some limitations of ordinary activity or work to slight or no pain after treatment. Given that the arthroscopic procedure was developed around 2004, long-term follow-up is limited.
 
What can be ascertained from the current literature:
    • 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.
    • Patients may present with hip pain that can be diagnosed as FAI by a combination of clinical evaluation, radiographs, and MR arthrography.
    • 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. FAI can be verified intraoperatively.
    • 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.
    • Treatment of FAI is most effective in younger patients without osteoarthritis (Tonnis grade 0 or I) or severe cartilage damage. Although osteoarthritis can be identified with plain film radiographs, articular damage is not always identified with current imaging techniques.
    • 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.
    • In large case series, arthroscopic treatment of FAI in young to middle-age patients without osteoarthritis and showing mild to moderate cartilage damage results in 75% to 85% of patients improved.
    • Smaller case series suggest that open treatment of FAI in young to middle-age patients with moderate to severe cartilage damage results 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.
 
What cannot be ascertained from the literature:
    • It is not known whether arthroscopic or open approaches result in better net health outcomes when patients are matched for severity of FAI morphology and articular cartilage damage.
    • 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.
    • It is not known whether treatment of FAI will reduce the occurrence of osteoarthritis.
 
Based on 1) the intraoperatively established relationship between FAI morphology and damage to the acetabulum, 2) the consistent improvement in symptoms reported in large prospective case series, and 3) the potential for continued and irreparable cartilage damage if FAI pathology is not addressed, open or arthroscopic treatment of FAI meets Primary Coverage Criteria of effectiveness when specific criteria are met.  Because of the differing benefits and risks of open and arthroscopic approaches, patients should make an informed choice.
 
The evidence is insufficient to permit conclusions concerning the effect of this procedure on the development of osteoarthritis. Therefore, treatment of FAI morphology in the absence of symptoms does not meet Primary Coverage Criteria of effectiveness.
 
2010 Update
 
This update mostly focuses on FAI after slipped capital femoral epiphysis (SCFE).  Sink et al. reported a retrospective review from 2 U.S. centers on 36 patients (39 hips) with stable SCFE who were treated with open surgical hip dislocation for chronic symptoms (Sink, 2010).  The degree of slip was considered to be mild in 8, moderate in 19, and severe in 11 patients, and the average time between in situ pinning and surgical hip dislocation was 20 months (range 6-48 months). The majority of patients had partial or complete relief of symptoms immediately after initial pinning followed by a recurrence of symptoms that were consistent with impingement. All but one patient had either labral or cartilage injury, with labral injury observed in 34 of 39 hips and cartilage injury in 33 or 39 hips (5 grade 1, 10 Grade 2, 4 Grade 3, 10 Grade 4, and 4 Grade 5); the average depth of cartilage damage was 5 mm (range 2-10 mm). There was no correlation between slip severity or duration of symptoms and the type of cartilage injury.
 
Dodds et al. examined the prevalence of FAI in 36 patients (49 hips) who returned for clinical evaluation at an average 6 years after SCFE (Dodds, 2009).  There was no difference in the grade of slip between those patients who were available for follow-up and the total cohort treated for SCFE. The average age at presentation was 12.2 years, and at the time of evaluation all patients had reached skeletal maturity. Postoperative radiographs were reviewed for the grade of slip, Southwick slip angle, Loder’s classification of physeal stability, and the anterior head-neck offset (alpha) angle. Pain and impingement were found in 30% of the 30 hips with Grade 1 slips, 25% of the 8 hips with Grade 2 slips, and 0% of the 4 hips with Grade 3 slips. None of the radiographic factors including the grade of slip were predictive of subsequent impingement; the alpha angle was the most influential variable in regression analysis. Together, these results indicate that it is difficult to predict which patients with SCFE will develop FAI, but that all children should be followed into adulthood and monitored for impingement.
 
The literature search identified several articles from specialized centers on the treatment of symptomatic FAI in children with developmental hip disorders. The largest series on SCFE was a joint retrospective review from the Swiss group of Ganz and Leunig, together with the Children’s Hospital Boston, with 1- to 8-year follow-up on 40 patients (between 9 and 18 years of age) with moderate to severe SCFE who were treated by capital realignment with surgical dislocation (Ziebarth, 2009). The primary aim of the article was to determine whether this capital realignment technique was feasible and repeatable, and would restore hip anatomy and function while avoiding osteonecrosis. Dislocation was not performed in SCFE with a slip angle of less than 30 degrees, in which trimming of the anterior metaphysis was considered sufficient to restore the anterior offset without weakening the femoral neck. No patients from either institution developed osteonecrosis, infection, deep venous thrombosis or nerve palsies. Three patients developed delayed unions, none developed non-unions. Five patients required additional surgery for heterotopic ossification, residual impingement, or breakage of screw or wire fixation. The short-term postoperative clinical outcomes were found to be near normal, with similar scores between the operative and non-operative hips. Stability and the duration of symptoms of SCFE (1 day to 3 years) were associated with the severity of acetabular cartilage damage observed at the time of surgery.
 
From the same U.S. institution was a 2006 report of 19 patients (12 – 43 years of age) who underwent either femoral neck osteoplasty or osteoplasty with intertrochanteric osteotomy via Ganz-type surgical dislocation (Spencer, 2006). Out of 12 patients with a history of SCFE (12-38 years of age), 9 were found to be improved at 8-25 months follow-up. Out of the 7 patients (17-43 years of age) without SCFE who underwent open surgical dislocation for pistol grip deformities, 5 had worse symptoms or minimal relief. Outcomes for patients with a chondral flap were worse than for patients without a chondral flap. For example, function scores on the WOMAC improved from a baseline of 26 to 10 in patients without a chondral flap, but did not improve (25 to 24) in patients with chondral flap damage.
 
Due to the unclear balance of risks and benefits, questions regarding whether, when and how to treat symptomatic FAI in children with SCFE are difficult. Although the impact of not treating FAI is established, there is limited evidence on treatment outcomes in pediatric patients. The open dislocation procedure is technically demanding with a high risk of serious complications and has not been shown to be safe and effective outside of a few highly specialized centers. In addition, questions remain concerning selection criteria and the appropriate timing and approach for FAI treatment in patients with developmental hip disorders. In a 2009 review of SCFE, surgeons from Children’s Hospital Boston considered subcapital correction osteotomy with surgical dislocation to be an emerging treatment, stating that “Currently, we recommend that this type of treatment should be restricted to few select specialized centers until the availability of long-term results and outcome. Also, this type of treatment has a steep learning curve, and it is advised to learn this surgical technique at a specialized center” (Gholve, 2009).  Since this approach has not been shown to be safe and effective outside of a few specialized centers, surgical treatment of FAI in pediatric patients does not meet primary coverage criteria that there be scientific evidence of effectiveness.  
 
2012 Update
This policy is being updated with a literature search using the MEDLINE database.  There was no new information identified that would prompt a change in the coverage statement. There is still limited evidence on treatment outcomes in the pediatric population. The key publications identified are summarized below.
 
Two systematic reviews comparing open and arthroscopic surgery for FAI have been identified (Matsuda, 2011) (Botser, 2011). Matsuda et al. included 18 level III or IV studies (controlled cohort or case series) with a minimum 1-year follow-up (Matsuda, 2011). There were 6 papers on open surgical dislocation, 4 on mini-open procedures, and 8 arthroscopic studies. All 3 approaches were found to be effective in improving pain and function in short-term to midterm studies. Open dislocation surgery had a comparatively high major complication rate primarily because of trochanteric osteotomy-related issues. The mini-open method showed comparable efficacy but a significant incidence of iatrogenic injury to the lateral femoral cutaneous nerve. Botser and colleagues included 26 level II to IV articles totaling 1,462 hips in 1,409 patients (Botser, 2011). Of these, 900 hips were treated arthroscopically, 304 with the open dislocation method, and 258 by the mini-open method. The mean time from onset of symptoms to surgery was 28 months. Overall complication rates were found to be 1.7% for the arthroscopic group, 9.2% for the open surgical dislocation group, and 16% for the combined approach group.
 
Poor outcomes following arthroscopic treatment of FAI in patients with arthritis have been reported. Larson et al. conducted a retrospective comparison of outcomes from arthroscopic treatment of 154 patients (169 hips) without joint space narrowing (Tonnis grade 0 to 1) and 56 patients (58 hips) with preoperative radiographic evidence of joint space narrowing (Tonnis grade 2 or 3) (Larson, 2011).  Although both groups had improved scores throughout 12-month follow-up, outcomes were better for patients without osteoarthritis than for patients with osteoarthritis. Patients with advanced preoperative joint space narrowing (n=22) showed no improvement after treatment for FAI. At 3-year follow-up, the mean Harris Hip score was 88 for the group without osteoarthritis and 67 for the group with osteoarthritis. The failure rate at the last follow-up, defined as a MHHS less than 70 or conversion to hip arthroplasty, was 12% for patients without osteoarthritis, 33% for hips with mild to moderate preoperative joint space narrowing (<50% joint space narrowing or >2 mm joint space), and 82% failure rate for hips with advanced preoperative joint space narrowing (>50% joint space narrowing or < 2 mm joint space). Multiple linear regression analysis revealed that increasing radiographic joint space narrowing, chondral grade on magnetic resonance imaging (MRI), and greater duration of symptoms preoperatively were independent predictors for lower Harris Hip scores. Another study reported outcomes from 20 patients (out of a series of 150) who showed generalized severe cartilage lesions during intraoperative arthroscopic assessment for FAI (Horisberger, 2010).  Nine hips had Tonnis grade I osteoarthritis, 6 had grade II, and 5 had grade III osteoarthritis. At a mean follow-up of 3 years, 10 patients (50%) had undergone, or planned to undergo, total hip replacement. Preoperatively, 5 of the 10 hips had Tonnis grade III osteoarthritis. Another 2 patients had a poor result at latest follow-up but were not yet willing to undergo THA. The mean time between the index surgery and THA was 1.4 years (range, 0.4 to 2.2 years). The authors concluded that in patients with generalized chondral lesions, arthroscopic treatment of FAI does not have any effect beyond the short-term pain relief resulting from debridement.
 
Philippon et al. evaluated outcomes following arthroscopic treatment of FAI in 153 consecutive patients aged 50 years or older (Philippon, 2012).  The mean age of the patients was 57 years (range, 50 to 77 years). The prospective database included range of motion, MHHS, Hip Outcome Score (HOS) for activities of daily living, HOS for sports, and SF-12 score preoperatively and at 6-months after surgery. Questionnaires were then mailed annually. THA was required after arthroscopy for FAI in 20% of patients at a mean of 1.6 years (range, 3 months to 4 years). In the patients who did not require THA, the MHHS improved from 58 to 84, the HOS for activities of daily living improved from 66 to 87, and the HOS for sports improved from 42 to 72. The physical component of the SF-12 improved from 38 to 49, with no change in the mental component. Survivorship, defined as not requiring hip replacement, was 92% at 1 year, 84% at 2 years, and 80% at 3 years. For the 64 patients who had data available at 3 years, patients with greater than 2 mm of joint space preoperatively had survivorship of 90% whereas those with 2 mm or less of joint space had survivorship of 57%. Logistic regression modeling adjusted for age and days from injury to surgery identified joint space of 2 mm or less and preoperative MHHS of less than 50 as risk factors for hip replacement.
 
Javed and O’Donnell reported arthroscopic treatment of cam-type FAI in 40 patients older than 60 years of age (mean 65 years; range 60 to 82) (Javed, 2011).   Patients were excluded from this retrospective study if they had Tonnis grade 2 or 3 osteoarthritis, pincer FAI, bilateral cam FAI, inflammatory or metabolic hip disease, hip dysplasia, Perthes disease, a history of fracture of the hip or previous surgery on the hip. Forty patients fulfilled the inclusion/exclusion criteria out of a total of 1,693 hip arthroscopies (2.4%) performed at their institution. In 17 patients there was no arthroscopic evidence of osteoarthritis in the hip; 23 had a variable degree of chondral loss from the acetabulum and/or femoral head. The MHHS and the non-arthritic hip score were collected pre-operatively and at 2, 6, 26, and 52 weeks post-operatively, and then on an annual basis. Follow-up was performed for a mean of 30 months (range, 12 to 54 months). The mean MHHS improved by 19.2 points (from 60.5 to 79.7), and the mean non-arthritic hip score improved by 15 points (from 62.1 to 77.2). Out of this selected group of 40 patients with unilateral cam impingement, equal to or less than Tonnis grade 1 osteoarthritis and a mean age of 63 years (range 60 to 70), 7 (17.5%), underwent total hip replacement at a mean interval of 12 months. All but one had evidence of severe synovitis, 4 of the 7 patients had grade 3 chondral loss from both the acetabulum and femoral head, while 3 had a grade 3 lesion of the acetabular cartilage. No fractures of the femoral neck occurred during the follow-up period.
 
2013 Update
A search of the MEDLINE database was conducted through April 2013. A summary of the key identified literature is included below.
 
The incidence of athletic pubalgia symptoms in professional athletes with symptomatic FAI was reported by Hammoud et al. in 2012 (Hammoud, 2012). Out of 38 professional athletes who underwent arthroscopic treatment for FAI, 32% had previously undergone surgery for athletic pubalgia. While none of the patients had returned to their previous level of play after isolated athletic pubalgia surgery, all 12 patients with treatment of both athletic pubalgia and FAI returned to professional competition. In another subset of 15 patients who presented with both athletic pubalgia and FAI, both sets of symptoms resolved after treatment of FAI alone.
 
In a  2012 review by Papalia et al., 31 studies (1713 patients) were identified that reported clinical, functional, and imaging outcomes after open or arthroscopic treatment of FAI (Papalia, 2012). A direct comparison of arthroscopic and open treatment of FAI was reported by Zingg et al. in 2013 (Zingg, 2013). Out of 200 patients with FAI who were invited to participate in this prospective study, 10 patients agreed to be randomly allocated to arthroscopy or open surgical hip dislocation and 28 patients agreed to participate in the study but selected their preferred treatment. The open and arthroscopic groups were generally comparable at baseline. Arthroscopic treatment of FAI resulted in a shorter hospital stay (3 vs. 5 days) and less time off work. The Harris hip score (HHS) was improved compared to open treatment at 6 weeks, 3 months, and 12 months. Overall, pain scores (Western Ontario and McMaster Universities Arthritis Index [WOMAC] and Visual Analog Score [VAS]) were lower with arthroscopy, reaching statistical significance on about half of the time points. Compared with the open surgical approach, arthroscopy resulted in morphological over-corrections at the head-neck-junction.
 
The largest prospective series is by Malviya et al., who reported on changes in quality of life (QoL) for 612 patients who were treated by a single surgeon (Malviya, 2012). Patients ranged in age from 14 to 75 years (mean of 36.7). At 1 year after surgery, QoL scores on the Rosser Index improved by at least 1 grade in 76.6% of patients, were unchanged in 14.4%, and decreased in 9%.
 
In 2012, Palmer et al. reported prospective 3-year follow-up on 201 procedures for cam-type FAI with a Tonnis grade of 1 or less (Palmer, 2012). The mean duration of symptoms before surgery was 59 months. At follow-up, the Nonarthritic Hip Score (NAHS) improved from a mean of 56.1 to 78.2 and VAS for pain improved from 6.8 to 2.7. There was a higher incidence of grade 4 acetabular chondral defect in the 12 patients who required hip arthroplasty during the follow-up period compared with patients who did not undergo arthroplasty, and patients with pincer resection had poorer results (NAHS improvement of 16.1) compared to patients with only cam-type FAI (NAHS improvement of 23.9). Of the 93 patients who were able to return for a final postoperative radiograph, 91(97.8%) had no change in the Tonnis grade. Subgroup analyses of patients who were 20 or younger and 60 or older showed no significant effect of age. Among the 48 patients who were excluded from this study due to acetabular chondral defects greater than 1.5 cm², 60% underwent hip replacement at a mean of 21.7 months (range, 2029 months).
 
 In 2013, Krych et al. reported a non-blinded RCT of labral repair versus labral debridement in 36 female patients with pincer-type or combined-type FAI (Krych, 2013). At a mean 32-month follow-up (range 12 to 48 months), both groups showed significant improvement in the Hip Outcome Score (HOS) compared to baseline. Compared to the debridement group, the repair group had better outcomes on activities of daily living HOS (91.2 vs. 80.9) and sports HOS (88.7 vs. 76.3). A greater number of patients in the repair group rated their hip function as normal or nearly normal (94% vs. 78%).
 
Arthroscopic treatment for cam type FAI in adolescents with open growth plates was reported in 2012/2013 (Tran, 2012). At a mean follow-up of 14 months (range, 1-2 years), prospectively collected data showed improvement on the MHHS from 77.39 to 94.15 and on the nonarthritic hip score (NAHS) from 76.34 to 93.18. Of the 34 consecutive patients included in the study, 78.1% returned to full sporting activity. No complications (e.g., avascular necrosis, SCFE, fracture, or growth plate arrest) were observed.
  
 
2014 Update
A literature search conducted through April 2014 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Treatment of FAI with Arthroscopic or Open Approaches
Bedi et al performed a systematic review of the literature on labral tears and FAI, with a literature review conducted in May 2008. (12) Level I, II, III, or IV study designs were included if the patient population had a labral tear and/or FAI as the major diagnosis. Patients with severe pre-existing osteoarthritis or acetabular dysplasia were excluded. Of the 19 studies included, only 1 met the criteria for level III basis of evidence. The studies reviewed suggested that 65% to 85% of patients will be satisfied with their outcome at a mean of 40 months after surgery. All series reported an increased incidence of failure among patients with substantial pre-existing osteoarthritis. The authors concluded that the quality of literature reporting outcomes of surgical intervention for labral tears and FAI is limited. A systematic review that included literature through April 2013 identified 29 studies (2369 patients); 83% were level IV evidence (case series), 14% were level III (cohort), and 3.4% were level I (RCT) (Harris, 2013). An arthroscopic approach was used in 59% of studies. The larger case series, including those published after the literature search for the systematic review by Bedi et al are described next.
 
Domb et al reported a matched-pair comparison of open vs arthroscopic treatment of FAI (Domb, 2013). Patients chose the procedure after discussion of the advantages and disadvantages of each approach. Ten patients who chose the open procedure were matched with 20 patients from a larger cohort of 785 patients who underwent arthroscopic treatment of FAI during the same period. Patients were matched for age, gender, diagnosis of FAI, and Worker’s Compensation status. The 2 groups had similar preoperative scores and both groups showed significant improvements postoperatively. At 2-year follow-up, the improvements in the Hip Outcome Score (HOS)-Sport-Specific Subscale (42.8 vs 23.5) and Non-Arthritic Hip Score (94.2 vs 85.7) were significantly higher in the arthroscopic group. There was no significant difference between the groups in the modified HHS, HOS-activities of daily living, or VAS for pain.
 
2015 Update
A literature search conducted through May 2015 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
A 2014 study by Thomas and colleaguesl found that subclinical deformities of the hip, including cam-type FAI, were significant predictors of radiographic osteoarthritis and joint replacement in women (Thomas, 2014). This was a population-based longitudinal cohort of 1003 women who underwent pelvis radiographs at years 2 and 20. Baseline morphology was available for 1466 hips (734 participants). At 20 years, blinded radiographic analysis was available for 670 hips (46% of total), of which 70 (11%) showed osteoarthritis. Data on total hip replacement at the 20 year assessment was available for 1455 hips (99% of total), of which 40 (3%) had undergone replacement. Pincer-type FAI at year 2 was not significantly associated with radiographic OA. Cam-type FAI at year 2 of the study, determined by alpha angle and Gosvig’s Triangular Index Height, was significantly associated with development of radiographic osteoarthritis and total hip replacement. Each degree increase in alpha angle above 65° was associated with an increase in risk of 5% for radiographic osteoarthritis and 4% for total hip replacement. This finding is limited by the low rate of participants having both baseline and follow-up radiographs.
 
Treatment of FAI With Arthroscopic or Open Approaches
Authors of a 2014 Cochrane review conducted a literature search for randomized and quasi-randomized clinical trials assessing surgical intervention compared with placebo treatment, non-operative treatment, or no treatment in adults with FAI (Wall, 2014). There were no studies that met the inclusion criteria. Four ongoing studies were identified (see Ongoing and Unpublished Clinical Trials).
 
A systematic review from 2015 identified 6 case series and 2 conference abstracts with a total of 388 children and adolescents who had been surgically treated for FAI (de Sa, 2015).  Ages of the patients ranged from 11 to 19.9 years. Although it was not reported how many of the patients had open growth plates, the authors noted that closure of the growth plates is initiated at ages 16 to 18 years, with 88% fusion at age 17 to 18 years and 100% fusion at 20 years of age. Most of the patients were treated with hip arthroscopy (315 arthroscopic and 73 open). The review indicated that surgical treatment of FAI was performed in 81% of patients, and all but 7 of 388 (1.8%) treated surgically were able to return to activity/sport. There were no reports of iatrogenic femoral neck fracture, instability/dislocation, acute SCFE, avascular necrosis, or premature physeal closure and proximal femoral growth arrest. Additional study is needed to evaluate the long-term effects on bone morphology following surgery for FAI in skeletally immature children.
 
Ongoing and Unpublished Clinical Trials
Ongoing and Unpublished Clinical Trials
Ongoing
(NCT01623843) Femoroacetabular Impingement RandomiSed Controlled Trial (FIRST); planned enrollment 220; projected completion date Jun 2017
 
(NCT01893034) A Randomised Controlled Trial of Surgical Versus Non-surgical Treatment of Femoroacetabular Impingement - Trial for Femoroacetabular Impingement Treatment (FAIT); planned enrollment 120; projected completion date Jul 2017
 
Unpublished
(NCT01621360) A Randomized Controlled Trial Comparing Arthroscopic Surgery to Conservative Management of Femoroacetabular Impingement; planned enrollment 140; projected completion date May 2014
 
2017 Update
A literature search conducted through May 2017 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Observational Studies
In 2016, Oner and colleagues conducted a retrospective study to determine the prevalence of FAI as an etiologic factor for OA in the hip joint among patients who had undergone THA (Oner, 2016). Radiographs of 1004 patients who had undergone THA between 2005 and 2010 were reviewed by 3 authors. Intra- and inter-observer consistencies were calculated. The predisposing etiologic factor leading to end-stage degenerative hip disease was undetermined in 26 of the radiographs. Among the remaining 978 patients, 99 patients were diagnosed with FAI by all 3 reviewers, 83 with a cam-type FAI and 16 with pincer-type FAI. Inter-observer agreement was high, with a contingency coefficient of 0.71 for the diagnosis of FAI between observers.
 
Arthroscopic Surgery
Evidence consists of a systematic review of observational studies and 1 small RCT.
 
Systematic Reviews
In 2017, Kierkegaard and colleagues published a systematic review and meta-analysis on patients with FAI who have undergone hip arthroscopy (Kierkegaard, 2017).  Outcomes were pain, activities of daily living (ADLs), and sport function. Databases were searched through September 2015. Nineteen studies were included in the meta-analysis: 15 case series, 3 cohorts, and 1 RCT. The RCT by Krych and colleagues is described below in the RCT section (Krych, 2013). Total number of patients was 2322 (mean age, 36 years; range, 18-57 years) and 42% women. Weighted mean differences between pre- and postoperative outcomes were used in the meta-analysis. Detectable pain reduction was achieved in less than 3 months, and maintained through 5 years. Improved ADLs were evident between 3 and 6 months, and maintained through at least 3 years of follow-up. Sport function improvements were detected between 6 and 12 months after arthroscopy and maintained through several years of follow-up. Average outcome scores indicated mild residual pain among patients when compared to healthy counterparts.
 
Comparisons of Open and Arthroscopic Surgeries
Systematic Reviews
Zhang and colleagues published a systematic review of studies that compared the efficacy and safety of hip arthroscopy versus open surgical dislocation for the treatment of FAI (Zhang, 2016). Five comparative studies published through August 2016 were included, evaluating a total of 352 hips. All studies were considered good or high quality based on the Newcastle-Ottawa scale. Length of follow-up among the studies ranged from 12 to 25 months. At the 3-month follow-up, patients undergoing open dislocation experienced significant improvements in alpha angle (-4.45; 95% CI, -8.22 to -0.67) compared with patients undergoing arthroscopy, while patients undergoing arthroscopy reported significantly better Non-arthritic Hip Scores (NAHS) (16.58; 95% CI, 9.54 to 23.61]) compared with patients undergoing open dislocation. At 12 months follow-up, NAHS remained significantly better in the group undergoing arthroscopy, though the modified Harris Hip Score and measures of ADLs and sports-specific scales were equivalent between the groups. Complications were also equivalent between the two groups, though reoperation rates were significantly lower in the patients undergoing arthroscopy (RR=0.4; 95% CI, 0.17 to 0.95).
 
Nwachukwu and colleagues published a systematic review and meta-analysis comparing open with arthroscopic surgical techniques for the treatment of FAI (Nwachukwu, 2016). The literature search included studies published through October 2014, which had a mean follow-up of at least 3 years. Sixteen studies met inclusion criteria: 9 open surgical hip dislocation studies and 7 hip arthroscopy studies. Pooled cohort analyses were conducted on data from 600 hips and mean follow-up of 58 months from the open surgery studies and 1484 hips and a mean follow-up of 51 months from the arthroscopy studies. Conversion to total hip arthroplasty (THA) was the outcome endpoint, with an overall survival rate of 93% for patients undergoing open surgery and 90.5% for patients undergoing arthroscopy (p=0.06). The 12-Item Short Form, an instrument for measuring general health-related quality of life, showed significantly better scores among patients undergoing arthroscopy. Direct comparison of other outcomes was limited by outcome instrument heterogeneity. Both surgical techniques demonstrated favorable outcomes in their respective measuring systems.
 
Mini-Open and Mixed Open/Arthroscopic Approaches
Evidence for mixed-open and open/arthroscopic approaches consists of observational studies.
 
Observational Studies
A mini-open surgical technique performed on 118 patients with FAI was described by Chiron and colleagues (Chiron, 2012). Fifty-eight percent had cam-type impingement and 42% had mixed type impingement. Average follow-up was 2.2 years. NAHS scores, internal rotation, and alpha angles significantly improved following surgery. Eight revisions were performed, 2 patients experienced residual pain and eventually underwent TKA, and 2 progressed rapidly to OA.
 
CHILDREN WITH SYMPTOMATIC FAI
Observational Studies
Guindani and colleagues published results from patients less than 18 years of age who were retrospectively identified as having undergone surgical dislocation for several different indications at a single institution (Guindani, 2017). Among the 51 patients (53 hips) in the study, 18 (34%) hips had the diagnosis of FAI. Patients with FAI reported significant improvements in the following pre- and post-measurements: MHHS, NAHS, and SF-12. No significant improvements were found in: sphericity deviation score, or on α angles (both antero-posterior and Lauenstein views).
 
REVISION ARTHROCOPIC SURGERY
Evidence for revision arthroscopic surgery for the treatment of patients with residual FAI consists of two systematic reviews published in 2015. The reviews, as well as an observational study on patients 18 years of age or younger that was published after the systematic reviews.
 
Systematic Reviews
Sardana and co0lleagues published a systematic review on revision hip arthroscopy, searching for articles through July 2014 (Sardana, 2015). Three prospective case control studies and 3 retrospective chart reviews, providing information on 448 hips, were included in the review. The most common indications for revision surgery were residual FAI, labral tears, and chondral lesions. The mean time interval between index and revision procedures was 25.6 months (range, 20.5-36 months). Patients most often requiring revision surgery were women (60%) and younger patients (mean age, 33.4 years). Revision hip arthroscopy resulted in improved functional outcomes (33.6% improvement in HHS) and pain relief. The authors noted that the studies were low quality (level III and IV).
 
Another systematic review published in 2015, by Cvetanovich and colleagues, evaluated revision hip arthroscopy (Cvetanovich, 2015). The review included 5 studies, with a total of 348 revision hip arthroscopies. Mean age of patients was 31.4 years and 60% were female. The mean time interval between index and revision procedures was 27.8 months. The most common indication for revision surgery was residual FAI (81%). Revision hip arthroscopy resulted in improved functional outcomes, measured by the HHS (WMD=56.8 (3.6) preoperative vs 72.0 (8.3) at a mean follow-up of 22.4 months; p=0.01), NAHS, Hip Outcome Score, and the SF-12.
 
Observational Study
A 2016 case-control study by Newman et al compared outcomes after revision hip arthroscopy with outcomes after primary hip arthroscopy among patients 18 years of age and younger (Newman, 2016) Each patient in the revision hip arthroscopic surgery group (n=42) was matched with 2 patients undergoing primary hip arthroscopic surgery (n=84). Outcomes included the HOS-ADLs, HOS-Sport Score, HSS, and SF-12 Physical Component Summary (PCS) score. Follow-up was conducted for a minimum of 2 years. There were no significant differences between the groups in HOS-ADL and SF-12 PCS. However, the primary arthroscopic surgery group had significantly higher scores in HOS-Sport Score, HHS, and patient satisfaction.
 
Section Summary: Revision Arthroscopic Surgery
The evidence for revision arthroscopic surgery for patients with residual FAI symptoms consists of 2 systematic reviews of observational studies. The observational studies, although low-quality, showed consistent favorable functional outcomes following revision surgery. Evidence for revision arthroscopic surgery for children consists of 1 observational study. Results show that children receiving revision surgery have comparable functional outcomes compared with children receiving primary arthroscopic surgery. Evidence is sufficient to determine the net health outcomes for the use of revision surgery on patients with residual FAI symptoms following primary surgery.
 
2018 Update
A literature search conducted through March 2018 did not reveal any new information that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Minkara et al (2018) published a systematic review and meta-analysis analyzing risk factors and outcomes after patients with FAI had undergone hip arthroscopy. Reviewers identified 29 relevant articles that included 1911 patients (1981 hips). Reviewers conducted a meta-analysis assessing return to play, revision rate, surgical and nonsurgical complications, change in α-angle, intraoperative bone resection, and patient-reported outcome measures after hip arthroscopy in FAI. However, all but 2 studies (1 RCT, 1 prospective cohort) in the meta-analysis were case series. Reviewers also sought to identify risk factors associated with intervention success and/or failure. The data on reoperation and complication rates are most relevant. The cumulative risk of reoperation after hip arthroscopy, including revision surgery or subsequent THA, was 5.5% (95% CI, 3.6% to 7.5%). For patients requiring a secondary procedure, 77% underwent THA, and 13% required revision arthroscopy. A single study was the source for 19% of patients requiring a second procedure, which assessed hip arthroscopy exclusively among patients who were 50 years of age and older (mean, 57 years; range, 50-77 years). The risk of clinically reported complications was 1.7% (95% CI, 0.9% to 2.5%) The most frequent complication was heterotopic ossification, followed by transient neurapraxia, typically of the lateral femoral cutaneous nerve and sciatic nerve.
 
Lund et al (2017) used data from the Danish Hip Arthroscopy Registry to report on outcomes for 1835 patients treated with 2054 FAI procedures between 2012 and 2015. At 1- and 2-year follow-ups, patient-related outcome measures (PROM) were: the European Quality of Life assessment, the Copenhagen Hip and Groin Outcome Score; the Hip Sports Activity Scale; and a numeric rating scale for pain. Although statistically significant improvements in all PROM scores were reported at one-year follow-up, there were no improvements in these measures between 1 and 2 years, with the exception of mean numeric rating scale pain scores for walking (preoperative, 49; 1 year, 27; 2 year, 22; p<0.05; 95% CI not reported). The authors concluded that patients with FAI could generally expect to see reductions in pain and improvements in QOL postsurgery.
 
Oduwole et al (2017) reviewed 15 case series identified in a literature search from 2005 to 2016 that reported on the efficacy of surgical management in patients with FAI secondary to slipped capital femoral epiphysis. A total of 261 patients (266 hips) underwent both arthroscopic and open procedures (arthroscopic osteochondroplasty, 85 patients [88 hips]; surgical hip dislocation, 131 patients [133 hips; open osteotomy, 45 patients [45 hips]). Mean alpha angle corrections observed for arthroscopy were 32.14 degrees; for surgical hip dislocation, 41.45 degrees; and for open osteotomy, 6.0 degrees (p<0.05). Surgical hip dislocation resulted in the most improved correction of the alpha angle.
 
Nwachukwu et al (2017) reviewed an institutional hip preservation registry of patients with FAI who underwent hip arthroscopy. The authors sought to define the minimal clinically important difference) and the substantial clinical benefit for adolescents undergoing hip arthroscopy. Data from 47 adolescents (68.1% female; mean age, 16.5 years) were obtained on the patients’ modified HHS, the HOS, and the international Hip Outcome Tool. Overall adolescent patients reported a minimal clinically important difference for the various patient-related outcomes but not substantial clinical benefit. The authors discussed the potential limitations of patient-related outcomes for adolescents compared with adults. They noted that adolescents might have higher expectations and greater physical activity demands that influence their scores.
 
Gwathmey et al (2017) reported on outcomes for 186 patients (190 hips) who underwent revision hip arthroscopy. All patients (mean age, 32.7 years; range 14-64 years) had undergone at least 1 prior hip arthroscopy (range, 1-6) and were prospectively assessed using the modified HHS at both baseline and 3, 12, 24 and 60 months postsurgery. FAI was treated in 79 revision cases. The mean improvement in the modified HHS for the FAI correction as the primary procedure was 27.4 months (mean follow-up, 44.7 months). The overall improvement for FAI correction revision was 21.9 points (mean follow-up, 43.5 months).

CPT/HCPCS:
27151Osteotomy, iliac, acetabular or innominate bone; with femoral osteotomy
27299Unlisted procedure, pelvis or hip joint
29861Arthroscopy, hip, surgical; with removal of loose body or foreign body
29862Arthroscopy, hip, surgical; with debridement/shaving of articular cartilage (chondroplasty), abrasion arthroplasty, and/or resection of labrum
29863Arthroscopy, hip, surgical; with synovectomy
29914Arthroscopy, hip, surgical; with femoroplasty (ie, treatment of cam lesion)
29915Arthroscopy, hip, surgical; with acetabuloplasty (ie, treatment of pincer lesion)
29916Arthroscopy, hip, surgical; with labral repair
29999Unlisted procedure, arthroscopy

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