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Surgical Treatment of Femoroacetabular Impingement

Section: Surgery
Effective Date: July 01, 2018
Revised Date: November 14, 2019


Femoroacetabular Impingement

FAI arises from an anatomic mismatch between the head of the femur and the acetabulum, causing 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 (e.g., 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.

Two types of impingement, cam, and pincer, 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.

Epidemiologic and radiographic studies have found correlations between hip osteoarthritis (OA) and FAI lesions, supporting the theory that prolonged contact between the anatomically mismatched acetabulum and femur may lead not only to cam and pincer lesions but also to further cartilage damage and subsequent joint deterioration. It is believed that osteoplasty of the impinging bone is needed to protect the cartilage from further damage and to preserve the natural joint. Therefore, if FAI morphology is shown to be an etiology of OA, a strategy to reduce the occurrence of idiopathic hip OA could be early recognition and treatment of FAI before cartilage damage and joint deterioration occurs.

An association between FAI and athletic pubalgia, sometimes called sports hernia, has been proposed. Athletic pubalgia is an umbrella term for a large variety of musculoskeletal injuries involving attachments and/or soft tissue support structures of the pubis.

Slipped Capital Femoral Epiphysis

Individuals with slipped capital femoral epiphysis (SCFE) have a displaced femoral head in relation to the femoral neck within the confines of the acetabulum, which can result in hip pain, thigh pain, knee pain, and the onset of a limp. SCFE occurs most frequently in children between the ages of 10 to 16. Upon reaching skeletal maturity individuals diagnosed with SCFE, 32% were found to have clinical signs of impingement. It is not uncommon for individuals with SCFE to develop premature OA and require total hip arthroplasty within 20 years.


Open or arthroscopic treatment of femoroacetabular impingement (FAI) may be medically necessary when all of the following conditions have been met:


  • Candidates should be skeletally mature with documented closure of growth plates (e.g., ≥15 years of age)


  • Moderate-to-severe hip pain 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° of flexion and internal rotation and adduction of the femur)


  • Morphology indicative of cam or pincer FAI (eg, pistol-grip deformity, femoral head-neck offset with an alpha angle >50°, 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 2 or 3, or joint space of less than 2 mm; and
  • No evidence of severe (Outerbridge grade IV) chondral damage

Treatment of FAI is considered investigational in all other situations.

Procedure Codes

29914 29915 29916

Diagnosis Codes

M24.151 M24.152 M24.159 M24.851 M24.852 M24.859 M25.551
M25.552 M25.559 M25.851 M25.852 M25.859 M94.251 M94.252
M94.259 S79.811A S79.811D S79.811S S79.812A S79.812D S79.812S
S79.819A S79.819D S79.819S S79.821A S79.821D S79.821S S79.822A
S79.822D S79.822S S79.829A S79.829D S79.829S S79.911A S79.911D
S79.911S S79.912A S79.912D S79.912S S79.919A S79.919D S79.919S
S79.929A S79.929D S79.929S

Professional Statements and Societal Positions Guidelines

Practice Guidelines and Position Statements

National Institute for Health and Care Excellence

The NICE (2011) issued guidance on arthroscopic femoroacetabular surgery for hip impingement syndrome. The NICE considered the evidence on the efficacy of arthroscopic femoroacetabular surgery for hip impingement syndrome to be adequate for symptom relief in the short and medium term.

The NICE’s (2011) guidance on open femoroacetabular surgery for hip impingement syndrome indicated that evidence for this procedure was adequate for symptom relief in the short and medium term.This guidance replaced IPG203.