Hip Femoroacetabular Impingement

Educational Objectives

The goal of this program is to improve the management of femoroacetabular impingement. After hearing and assimilating this program, the clinician will be better able to:

1. Differentiate between cam and pincer impingement.
2. Develop a safe approach to treating femoroacetabular impingement.

Summary

Anatomy of the hip: it is a ball-and-socket joint with a capsule that has thick ligaments within; among the 3 main ligaments, the iliofemoral ligament is the most relevant for hip injuries and preservation

Biomechanics of the hip: the leg is connected to the body by the hip joint; the range of motion (ROM) of the hip is controlled by bony constraints (interacts with the pelvic joints); during the single-stance phase, the femoral head (FH) acts as a fulcrum and supports the body in the lower extremities with the assistance of surrounding muscles; in a single-leg stance, the hip joint supports ≤10 times the weight of the body; morphologic abnormalities can lead to cartilage and labral damage; hip dysplasia is characterized by a shallow hip socket; tightness of the hip or bony morphology leads to hip impingement

Hip impingement: a clinical syndrome in which the anatomic abnormalities of the FH and/or the acetabulum result in abnormal contact during hip motion (especially in hip flexion and rotation), which can lead to cartilage and hip damage; the most common cause of hip pain and dysfunction among athletes; causes early-onset arthritis; the most common indication for hip arthroscopy

Cam impingement: occurs on the femoral side; more common in men; the FH loses its round shape and, in flexion, abuts the articular surface of the acetabulum and labrum, causing damage over time; the misshaped ball rolls in the socket and damages the cartilage (can be severely damaged without symptoms until the labrum itself starts to tear); may be developmental or genetic, in which there is familial history of femoroacetabular impingement (FAI) or arthritis; young athletes may be at increased risk of developing cam deformity

Pincer impingement: occurs during hip flexion or internal rotation, when an overhanging rim abuts the femoral head-neck junction (FHNJ); often combined with cam deformity; more painful than cam deformity and presents earlier; has a genetic component and is seen with pelvic deformities; acquired pincer deformity occurs when patients develop ossification or calcification of the labrum, which can result in arthritis

Femoroacetabular impingement: presentation — pain in the groin and lateral hip that worsens with deep flexion and twisting of the hip; hip injuries tend to localize to the groin; onset of symptoms is usually insidious; progressive pain worsens when seated for a long time and upon standing up; may also present with other pains (eg, back or pubic pain) because of severe stiffness of the hip joint, which can lead to secondary symptoms

Examination: patients can present with C sign (cupping of the hand around the outside of the hip, indicating that pain is located between the forefinger and thumb); ROM of the hip is limited, with extreme pain during flexion; the main sign is pain with the impingement position, ie, flexion, adduction, and internal rotation

Imaging: x-ray — the most useful diagnostic tool, as it can reveal cam deformity and the overall shape of the joint to rule out dysplasia and ensure there is no arthritis or overcoverage; anteroposterior x-ray can reveal crossover signs (eg, acetabular retroversion), which indicate pincer deformity; useful for evaluation of the joint space and identification of secondary signs of arthritis; magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) — may be useful for evaluation of soft tissues; MRI is helpful for detecting effusions or subchondral edema; MRA provides better visualization of the labrum and excellent cross-sectional imaging of morphology; on MRI, it is important to evaluate for bone edema or cysts (particularly, subchondral cysts); computerized tomography (CT) — useful for bony morphology

Treatment: first approach is modifying activity to avoid impingement positions; anti-inflammatory drugs are the first-line of treatment; physical therapy is beneficial; image-guided injection is useful for diagnosing the cause of pain and providing treatment that reduces inflammation inside the joint; historically, treatment of FAI involved open surgery; currently, surgical hip dislocation is used to obtain a circumferential view of the hip joint and allow for reshaping; some physicians prefer a “mini-open procedure,” in which the hip is not dislocated but is accessed through an anterior approach

Hip arthroscopy: the gold standard for treatment of FAI; a surgical approach that allows for better visualization of damage in the joint through the use of an arthroscope; fluid is used to distend the joint and aid in visualization and instrumentation; helpful for diagnosing the pattern of injury and removing impingement; it is imperative to remove the factors that are causing the labral or cartilage damage; performing an acetabuloplasty improves overall morphology of the FHNJ; labral repair is the gold standard for treatment of labral pathology

Rehabilitation: hip arthroscopy is an outpatient procedure (safe for same-day discharge); offloading the hip and preventing gait disturbances is a crucial part of rehabilitation; physical therapy should begin immediately after surgery, ie, moving the hips to avoid development of adhesions and muscle atrophy by improving ROM (with, eg, stationary bicycling, isometric exercises); avoid deep flexion and pressure to the labrum, as well as excessive rotation to prevent complications in the hip joint capsule; most patients typically return to unrestricted activity by ≈5 mo after surgery

Outcomes and complications: outcomes vary depending on the patient; young patients with correction of deformities and treatable labral tears tend to have good outcomes, whereas patients with degenerative joint diseases or secondary pain sources have poorer outcomes; transient cutaneous neurapraxia is the most common complication of hip arthroscopy; other complications include stiffness (requires therapy), instability, blood clots, and infections

Therapeutic advancements: labral reconstruction by replacement of the labrum using cadaver graft or autograft can be effective; new cartilage is evolving via cell-based procedures and osteochondral allografts for the hip; hip arthroscopy has been extended to extraarticular conditions, eg, gluteus medius tear, deep gluteal space syndrome, and hamstring tear

Readings

Cheatham SW, Enseki KR, Kolber MJ. Postoperative rehabilitation after hip arthroscopy: a search for the evidence. J Sport Rehabil. 2015; 24:413-418; doi: 10.1123/JSR.2014-0208a; Gatz M, Driessen A, Eschweiler J, et al. Arthroscopic surgery versus physiotherapy for femoroacetabular impingement: a meta-analysis study. Eur J Orthop Surg Traumatol. 2020; 30:1151-1162; doi: 10.1007/s00590-020-02675-6; Hasan K, Shankar S, Sharma A, et al. Hip surgery and its evidence base: progress over a decade? J Orthop Traumatol. 2016; 17:291-295; doi: 10.1007/s10195-016-0421-z; Khan M, Bedi A, Fu F, et al. New perspectives on femoroacetabular impingement syndrome. Nat Rev Rheumatol. 2016; 12:303-310; doi: 10.1038/nrrheum.2016.17; Lee CB, Kim YJ. Imaging hip dysplasia in the skeletally mature. Orthop Clin North Am. 2012; 43:329-342; doi: 10.1016/j.ocl.2012.05.007; Pennock AT, Bomar JD, Johnson KP, et al. Nonoperative management of femoroacetabular impingement: a prospective study. Am J Sports Med. 2018;46:3415-3422; doi: 10.1177/0363546518804805; Polkowski GG, Clohisy JC. Hip biomechanics. Sports Med Arthrosc Rev. 2010; 18:56-62; doi: 10.1097/JSA.0b013e3181dc5774; Schmaranzer F, Kheterpal AB, Bredella MA. Best practices: Hip femoroacetabular impingement. AJR Am J Roentgenol. 2021;216(3):585-598. doi:10.2214/AJR.20.22783; Teichtahl AJ, Quirk E, Harding P, et al. Weight change following knee and hip joint arthroplasty-a six-month prospective study of adults with osteoarthritis. BMC Musculoskelet Disord. 2015; 16:137; doi: 10.1186/s12891-015-0598-y; Zhang C, Li L, Forster BB, et al. Femoroacetabular impingement and osteoarthritis of the hip. Can Fam Physician. 2015; 61:1055-1060.

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, members of the faculty and planning committee reported nothing to disclose. In his lecture, Dr. Gwathmey presents information related to the off-label or investigational use of a therapy, product, or device.

Acknowledgements

Dr. Gwathmey was recorded exclusively for Audio Digest using virtual teleconference software, in compliance with social-distancing guidelines during the COVID-19 pandemic. Audio Digest thanks the speakers for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

OR442101

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.