Genetic influences in the aetiology of femoroacetabular impingement: a sibling study

Timing From Symptom Onset to Hip Arthroscopy Does Not Affect Patient-Reported Outcome Measures for the Treatment of Femoroacetabular Impingement in Adolescent Patients

PURPOSE

To evaluate symptom duration and its relationship to patient-reported outcomes (PROs) and survivorship after hip arthroscopy in adolescents.

METHODS

Patients ≤18 at time of primary hip arthroscopy for femoroacetabular impingement (FAI) between January 2011 and September 2018 were included. Exclusion criteria consisted of history of previous ipsilateral hip surgery, presence of osteoarthritis or dysplasia on preoperative radiographs, previous hip fracture, or history of slipped capital femoral epiphysis or Legg-Calve-Perthes disease. Minimum 2-year PROs (modified Harris Hip Score, Hip Outcome Score [HOS]-Activities of Daily Living, HOS-Sport Scale, Short Forms 12 [SF-12]), minimum clinically significant difference (MCID) and patient-acceptable symptom state (PASS) rates, and revision surgery rates were compared based on symptom duration.

RESULTS

Two-year minimal follow-up was obtained for 111 patients (134 hips) (80%), including 74 females and 37 males with a mean age of 16.4 ± 1.1 (range 13.0-18.0). The mean symptom duration was 17.2 ± 15.2 months (range 43 days to 6.0 years). Ten patients (11 hips), 6 females (7 hips) and 4 males, required revision surgery at an average of 2.3 ± 1.0 years (range 0.9-4.3 years). At a mean follow-up of 4.8 ± 2.2 years (range 2-10 years), there were statistically significant improvements in all PROs (P < .05 for all). Symptom duration showed no significant correlation to post-operative scores (correlation coefficient range -0.162 to -0.078, P > .05 for all). Symptom duration ≤12 months versus >12 months or as a continuous variable was not a predictor for requiring revision surgery or achieving MCID/PASS (95% confidence interval crosses 1 for all).

CONCLUSIONS

In an adolescent cohort of symptomatic FAI patients who underwent hip arthroscopy, there is no difference in PRO measures when analyzing symptom duration by arbitrary time intervals or as a continuous variable.

LEVEL OF EVIDENCE

Level IV, case series.

Inflammatory and Immunologic Contributions in Femoroacetabular Impingement Syndrome

Femoroacetabular impingement (FAI) is one of the most common causes of labral and early cartilage damage in the nondysplastic hip. FAI is increasingly recognized as a cause for hip and groin pain in the young, active patient, and the surgical treatment of FAI with hip arthroscopy has risen exponentially. Although our understanding of FAI and the progression to degenerative osteoarthritis of the hip has historically been considered a mechanical "wear-and-tear" disease of an imperfectly shaped, aspherical, femoral head within a deep or overcovering acetabulum leading to cartilage injury, our understanding of the intrinsic pathophysiologic mechanisms underlying the development of FAI and joint degeneration of the hip remains poor. For example, many patients with FAI morphology may never develop hip pain or osteoarthritis; there remains more to discover regarding the pathophysiology of arthritis in the setting of FAI. Recent work has begun to identify a strong inflammatory and immunologic component to the FAI disease process that affects the hip synovium, labrum, and cartilage and may be detectable from peripheral clinical samples (blood and urine). This review highlights our current understanding of the inflammatory and immunologic contributions to FAI and potential therapeutic strategies to supplement and augment the surgical management of FAI.

[Femoroacetabular impingement in adolescents]

Femoroacetabular impingement syndrome (FAIS) is caused by a repetitive mechanical conflict between the acetabulum and the proximal femur, occurring in flexion and internal rotation. In cam impingement, bony prominences of the femoral head-neck junction induce chondrolabral damage. The acetabular type of FAIS, termed pincer FAIS, may be either due to focal or global retroversion and/or acetabular overcoverage. Combinations of cam and pincer morphology are common. Pathological femoral torsion may aggravate or decrease the mechanical conflict in FAI but can also occur in isolation. Of note, a high percentage of adolescents with FAI-like shape changes remain asymptomatic. The diagnosis of FAIS is therefore made clinically, whereas imaging reveals the underlying morphology. X‑rays in two planes remain the primary imaging modality, the exact evaluation of the osseous deformities of the femur and chondrolabral damage is assessed by magnetic resonance imaging (MRI). Acetabular coverage and version are primarily assessed on radiographs. Evaluation of the entire circumference of the proximal femur warrants MRI which is further used in the assessment of chondrolabral lesions, and also bone marrow and adjacent soft tissue abnormalities. The MRI protocol should routinely include measurements of femoral torsion. Fluid-sensitive sequences should be acquired to rule out degenerative or inflammatory extra-articular changes.

Moderate and High Sport Specialization Level in Ice Hockey Athletes Is Associated With Symptomatic Cam Deformity

BACKGROUND

There is a known association between ice hockey and cam deformity in growing athletes. Similarly, the association between sport specialization and overuse injury in youth athletes has been well established. Limited research exists examining the relationship between cam deformity and sport specialization.

HYPOTHESIS/PURPOSE

Our hypothesis was that there would be a positive association with cam deformity and sport specialization category.

STUDY DESIGN

Retrospective chart review and cross-sectional questionnaire study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Study participants included athletes aged 15 to 25 years with symptomatic femoroacetabular impingement (FAI) and considered ice hockey as their primary sport. All participants had completed Dunn lateral radiographs or hip magnetic resonance imaging as part of their clinical evaluation. All participants completed a survey regarding sport specialization level. Multivariable linear regression analysis controlling for sex was used to analyze the association between degree of sport specialization, age of sport specialization, position played, and level played. Comparisons in radiographic parameters across ice hockey groups were conducted using Student t tests and chi-square tests.

RESULTS

Sixty-six ice hockey participants made up the cohort. The majority reported high sport specialization (41/66, 62%). The mean age of sport specialization was 10.7 years (SD 3.5). Participants with moderate specialization had 25 times the odds of a cam deformity (odds ratio [OR] 25.2; 95% CI 1.5-410.7; P = 0.02) and those with high specialization had 9 times the odds of cam deformity (OR 9.3; 95% CI 1.2-74.2; P = 0.04) compared with those with a low degree of specialization, controlling for patient sex. No association was detected between the age of specialization and the likelihood of cam deformity when controlling for patient sex.

CONCLUSION

Level of sport specialization was associated with a cam deformity in this cohort of youth ice hockey athletes.

CLINICAL RELEVANCE

This study suggests that an association exists.

Three-Dimensional CT and 3D MRI of Hip- Important Aids to Hip Preservation Surgery

Common hip internal derangements include femoroacetabular impingement (FAI), developmental dysplasia of hip (DDH) dysplasia, and avascular necrosis (AVN) of the femoral head. These are initially screened by radiographs. For preoperative planning of hip preservation, 3-dimensional (3D) CT is commonly performed to assess bony anatomy and its alterations. Magnetic resonance imaging (MRI) is used to evaluate labrum, hyaline cartilage, tendons, synovium, and loose bodies, and provides vital information for surgical decision-making. However, conventional 2D MRI techniques are limited by lack of isotropic multiplanar reconstructions and partial volume artifacts. With advancements in hardware and software, novel isotropic 3D MR Proton Density images are acquired with acceptable acquisition times leading to improved visualization of soft tissue and osseous structures for various hip conditions. Three-Dimensional MRI allows multiplanar non-gap reconstructions along the structures of interest. It results in detection of small, otherwise inconspicuous labral tears without the need for MR arthrogram, which can be subsequently measured. In addition, radial reconstructions of the femoral head can be performed from original 3D volume MR imaging and CT imaging without the need for individual different plane acquisitions. Three-Dimensional MRI thus impacts surgical decision-making for the important common hip derangement conditions. For example, femoral head hyaline cartilage loss may make hip preservation difficult or impossible. In this review, we discuss the advantages and technical details of 3D CT and MRI and their significant role in aiding hip preservation surgery for common hip conditions. The conditions discussed in this article include FAI, DDH, AVN, synovial disorders, cartilaginous tumors, and hip fractures.

Hip Pain and Movement Dysfunction Associated With Nonarthritic Hip Joint Pain: A Revision

The Academy of Orthopaedic Physical Therapy (AOPT), formerly the Orthopaedic Section of the American Physical Therapy Association (APTA), has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). This is an update to the 2014 Clinical Practice Guideline (CPG) for Hip Pain and Movement Dysfunction Associated with Nonarthritic Hip Joint Pain. The goals of the revision were to provide a concise summary of the contemporary evidence since publication of the original guideline and to develop new recommendations or revise previously published recommendations to support evidence-based practice. This current CPG covers pathoanatomical features, clinical course, prognosis, diagnosis, examination, and physical therapy interventions in the management of nonarthritic hip joint pain. J Orthop Sports Phys Ther 2023;53(7):CPG1-CPG70. doi:10.2519/jospt.2023.0302.

Open and arthroscopic management of femoroacetabular impingement: a review of current concepts

Femoroacetabular impingement (FAI) is a common femoral and/or acetabular abnormality that can cause progressive damage to the hip and osteoarthritis. FAI can be the result of femoral head/neck overgrowth, acetabular overgrowth or both femoral and acetabular abnormalities, resulting in a loss of native hip biomechanics and pain upon hip flexion and rotation. Radiographic evidence can include loss of sphericity of the femoral neck (cam impingement) and/or acetabular retroversion with focal or global overcoverage (pincer impingement). Operative intervention is indicated in symptomatic patients after failed conservative management with radiographic evidence of impingement and minimal arthritic changes of the hip, with the goal of restoring normal hip biomechanics and reducing pain. This is done by correcting the femoral head-neck relationship to the acetabulum through femoral and/or acetabular osteoplasty and treatment of concomitant hip pathology. In pincer impingement cases with small lunate surfaces, reverse periacetabular osteotomy is indicated as acetabular osteoplasty can decrease an already small articular surface. While surgical dislocation is regarded as the traditional gold standard, hip arthroscopy has become widely utilized in recent years. Studies comparing both open surgery and arthroscopy have shown comparable long-term pain reduction and improvements in clinical measures of hip function, as well as similar conversion rates to total hip arthroplasty. However, arthroscopy has trended toward earlier improvement, quicker recovery and faster return to sports. The purpose of this study was to review the recent literature on open and arthroscopic management of FAI.

Outcomes in Pediatric Hip FAI Surgery: a Scoping Review

PURPOSE OF REVIEW

Femoracetabular impingement (FAI) is a common source of hip pain in children and adolescents. While nonoperative therapies and open surgical procedures can be effective, hip arthroscopy is a minimally invasive treatment option with substantial benefit. The purpose of this paper is to evaluate the current role of hip arthroscopy in treating FAI within the pediatric population. This article examines its efficacy through a review of hip arthroscopy outcomes in the contemporary orthopaedic literature.

RECENT FINDINGS

Morphologic changes in the acetabulum and proximal femur seen in FAI can be attributed to a multitude of etiologies-including idiopathic FAI, Legg-Calve-Perthes, and slipped capital femoral epiphysis. In general, arthroscopic treatment of FAI secondary to these conditions leads to statistically significant improvements in pain and patient-reported outcomes in the short and long term. In the pediatric athlete, repetitive stress on the hip perpetuates FAI and can drastically hinder performance. Hip arthroscopy allows for a high rate of return to sport with minimal morbidity in this population. Overall, pediatric hip arthroscopy is effective in treating FAI secondary to a wide variety of conditions. Despite its clinical benefits, patients and their families should be counseled regarding alternative treatments, potential complications, and return to play.

Prevalence of femoroacetabular impingement in elite baseball players

CAM-type femoroacetabular impingement continues to be an underrecognized cause of hip pain in elite athletes. Properties inherent to baseball such as throwing mechanics and hitting may enhance the risk of developing a cam deformity. Our goal is to gain an appreciation of the radiographic prevalence of cam deformities in elite baseball players. Prospective evaluation and radiographs of 80 elite baseball players were obtained during the 2016 preseason entrance examination. A sports medicine fellowship-trained orthopedic surgeon with experience treating hip disorders used standard radiographic measurements to assess for the radiographic presence of cam impingement. Radiographs with an alpha angle &gt;55° on modified Dunn views were defined as cam positive. Of the 122 elite baseball players included in our analysis, 80 completed radiographic evaluation. Only 7.3% (9/122) of players reported hip pain and 1.6% (4/244) had a positive anterior impingement test. The prevalence of cam deformities in right and left hips were 54/80 (67.5%) and 40/80 (50.0%), respectively. The mean alpha angle for cam-positive right and left hips were 64.7 ± 6.9° and 64.9 ± 5.8°, respectively. Outfielders had the highest risk of right-sided cam morphology (Relative Risk (RR) = 1.6). Right hip cam deformities were significantly higher in right-handed pitchers compared with left-handed pitchers (P = 0.02); however, there was no significant difference in left hip cam deformities between left- and right-handed pitchers (P = 0.307). Our data suggest that elite baseball players have a significantly higher prevalence of radiographic cam impingement than the general population.

Does the Type of Sport Influence Morphology of the Hip? A Systematic Review

BACKGROUND

Femoroacetabular impingement (FAI) has been extensively investigated and is strongly associated with athletic participation.

PURPOSE

To assess (1) the prevalence of cam-type FAI across various sports; (2) whether kinematic variation among sports influences hip morphology; and (3) whether performance level, duration, and frequency of participation or other factors influence hip morphology in a sporting population.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic search of Embase, PubMed, and the Cochrane Library was undertaken following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Prospective and retrospective case series, case reports, and review articles published after 1999 were screened, and those that met the inclusion criteria decided a priori were included for analysis.

RESULTS

The literature search identified 58 relevant articles involving 5683 participants. A total of 49 articles described a higher prevalence of FAI across various "hip-heavy" sports, including soccer, basketball, baseball, ice hockey, skiing, golf, and ballet. In studies including nonathlete controls, a greater prevalence of FAI was reported in 66.7% of studies (n = 8/12). The highest alpha angle was identified at the 1-o'clock position (n = 9/9) in football, skiing, golf, ice hockey, and basketball. The maximum alpha angle was located in a more lateral position in goalkeepers versus positional players in ice hockey (1 vs 1:45 o'clock). A positive correlation was also identified between the alpha angle and both age and activity level (n = 5/8 and n = 2/3, respectively) and between prevalence of FAI and both age and activity level (n = 2/2 and n = 4/5).

CONCLUSION

Hip-heavy sports show an increased prevalence of FAI, with specific sporting activities influencing hip morphology. There is some evidence to suggest that a longer duration and higher level of training also result in an increased prevalence of FAI.

REGISTRATION

CRD4202018001 (PROSPERO).

Proximal femoral epiphyseal spurs and their association with acetabular labral tears on MRI in symptomatic patients

OBJECTIVE

Femoral epiphyseal spurs are developmental projections that form at the edge of the physis. Although considered incidental, their association with acetabular labral tears has never been examined. Our aim was to assess the prevalence of femoral epiphyseal spurs in symptomatic patients with mechanical hip pain and explore if they are associated with labral tears on MRI.

MATERIALS AND METHODS

Hip MRI scans performed on a Siemens 3 T MRI using femoroacetabular impingement protocol were retrospectively reviewed. All patients were referred by orthopaedic surgeons for mechanical hip pain. Two musculoskeletal radiologists blinded to initial reports evaluated MRI images for the presence of an epiphyseal spur and acetabular labral changes. A consensus was achieved on all cases by the two readers. The association between epiphyseal spurs and labral changes was assessed using Fisher's exact test.

RESULTS

A total of 115 patients (178 hip MRI scans) were reviewed; the mean age was 28.8 years (SD 7.1). There were 52 females (45.2%) and 63 males (54.8%). There were 115 hips with labral tears (64.6%). Fourteen hips (7.8%) in ten patients (8.7%) demonstrated epiphyseal spurs and all of them showed labral tears (100%). There was statistically significant association between epiphyseal spurs and labral tears on MRI (p value = 0.0024).

CONCLUSION

Femoral epiphyseal spurs were observed in 8.7% of our defined patient population, and all patients with epiphyseal spurs demonstrated labral tears. Epiphyseal spurs should be documented on imaging reports due to their potential association with labral tears. Future research is needed to further delineate and guide management of these entities.

How does the cam morphology develop in athletes? A systematic review and meta-analysis

OBJECTIVE

A higher prevalence of cam morphology has been reported in the athletic population but the development of the cam morphology is not fully understood. The purpose of this systematic review is to establish the timing of development of the cam morphology in athletes, the proximal femoral morphologies associated with its development, and other associated factors.

DESIGN

Embase, MEDLINE and the Cochrane Library were searched for articles related to development of the cam morphology, and PRISMA guidelines were followed. Data was pooled using random effects meta-analysis. Study quality was assessed using the Downs and Black criteria and evidence quality using the GRADE framework.

RESULTS

This search identified 16 articles involving 2,028 participants. In males, alpha angle was higher in athletes with closed physes than open physes (SMD 0.71; 95% CI 0.23, 1.19). Prevalence of cam morphology was associated with age during adolescence when measured per hip (β 0.055; 95% CI 0.020, 0.091) and per individual (β 0.049; 95% CI 0.034, 0.064). Lateral extension of the epiphysis was associated with an increased alpha angle (r 0.68; 95% CI 0.63, 0.73). A dose-response relationship was frequently reported between sporting frequency and cam morphology. There was a paucity of data regarding the development of cam morphology in females.

CONCLUSIONS

Very low and low quality evidence suggests that in the majority of adolescent male athletes, osseous cam morphology developed during skeletal immaturity, and that prevalence increases with age. Very low quality evidence suggests that osseous cam morphology development was related to lateral extension of the proximal femoral epiphysis.

Primary cam morphology; bump, burden or bog-standard? A concept analysis

BACKGROUND

Cam morphology, a distinct bony morphology of the hip, is prevalent in many athletes, and a risk factor for hip-related pain and osteoarthritis. Secondary cam morphology, due to existing or previous hip disease (eg, Legg-Calve-Perthes disease), is well-described. Cam morphology not clearly associated with a disease is a challenging concept for clinicians, scientists and patients. We propose this morphology, which likely develops during skeletal maturation as a physiological response to load, should be referred to as primary cam morphology. The aim of this study was to introduce and clarify the concept of primary cam morphology.

DESIGN

We conducted a concept analysis of primary cam morphology using articles that reported risk factors associated with primary cam morphology; we excluded articles on secondary cam morphology. The concept analysis method is a rigorous eight-step process designed to clarify complex 'concepts'; the end product is a precise definition that supports the theoretical basis of the chosen concept.

RESULTS

We propose five defining attributes of primary cam morphology-tissue type, size, site, shape and ownership-in a new conceptual and operational definition. Primary cam morphology is a cartilage or bony prominence (bump) of varying size at the femoral head-neck junction, which changes the shape of the femoral head from spherical to aspherical. It often occurs in asymptomatic male athletes in both hips. The cartilage or bone alpha angle (calculated from radiographs, CT or MRI) is the most common method to measure cam morphology. We found inconsistent reporting of primary cam morphology taxonomy, terminology, and how the morphology is operationalised.

CONCLUSION

We introduce and clarify primary cam morphology, and propose a new conceptual and operational definition. Several elements of the concept of primary cam morphology remain unclear and contested. Experts need to agree on the new taxonomy, terminology and definition that better reflect the primary cam morphology landscape-a bog-standard bump in most athletic hips, and a possible hip disease burden in a selected few.

Unusual apical femoral head deformity treated by hip arthroscopy and tunnel drilling through femoral head: a case report

Femoro-acetabular impingement (FAI), is the result of an abnormal morphology of the hip joint. On the femoral side, asphericity of the head can be highlighted by an alpha angle measurement >50° on computed tomography or MRI. However, some particular cephalic asphericities can make it difficult to measure the alpha angle, leading to a diagnostic pitfall. While in the classic cam effect, the deformity is peripheral and can be treated by arthroscopic femoroplasty, an apical head deformity remains a therapeutic challenge. We present the case of a 17-year-old male patient with a femoral head deformity, corresponding to an ISHA zone 6 overhang, significantly improved in everyday and sports life by arthroscopic trapdoor technique to resect the focal central deformity while enabling concomitant treatment of central compartment pathology, in this case, a hypertrophic ligamentum teres and femoral head chondral flap. Etiology of this femoral head deformity remains uncertain but could be a particular cam deformity, sequelae to pediatric disease or instability with repeated traction of the ligament teres on the femoral head apical insertion during cephalic growth.

Characteristics of femoroacetabular impingement morphology and relation with skeletal maturity among asymptomatic adolescents

The aim of this study was to analyze presence of the morphological characteristics and prevalence of FAI in asymptomatic adolescents and assess the relation of skeletal maturation with development of FAI morphology. Abdominopelvic computed tomography (CT) of 265 adolescents (9-19 years old) who were admitted to the emergency department between 2011 and 2016 were evaluated retrospectively. Radial reformatted CT images from the femoral neck were created using the multiplanar reconstruction (MPR) method. The femoral neck was divided into 12 segments and alpha angle (AA), femoral head-neck ratio (FHNR) and center-edge angle (CEA) were measured from each segment. Additionally, images were evaluated for the physiological status (open or closed) of the triradiate- cartilage and proximal femoral epiphyses. 204 hips from 102 patients (32 females, 70 males) were retrospectively reviewed. There were 27 (26.5%) patients with cam-type morphology and 18 (17.6%) patients with pincer-type morphologies. No statistically significant difference was detected between the prevalences of cam and pincer morphologies between the two genders. Cam deformity was most frequently seen in anterosuperior segment. All of the patients (100%) with pincer-type morphology and 88% of the patients with cam-type morphology had closed triradiate cartilage, 89% of the patients with cam morphology and 83% with pincer morphology had open proximal femoral physis. Our results showed that prevalence of cam and pincer-type morphology in asymptomatic adolescents is similar to asymptomatic adults. Our findings also indicate that cam- and pincer-type FAI morphologies likely develop during late adolescence after closure of triradiate cartilage and before closure of proximal femoral physis. Level of Evidence - 3

Genes associated with inflammation and bone remodeling are highly expressed in the bone of patients with the early-stage cam-type femoroacetabular impingement

BACKGROUND

Recent studies have shown high expression levels of certain inflammatory, anabolic, and catabolic genes in the articular cartilage from the impingement zone of the hips with femoroacetabular impingement (FAI), representing an increased metabolic state. Nevertheless, little is known about the molecular properties of bone tissue from the impingement zone of hips with FAI.

METHODS

Bone tissue samples from patients with early-stage cam-type FAI were collected during hip arthroscopy for treatment of cam-type FAI. Control bone tissue samples were collected from six patients who underwent total hip replacement because of a femoral neck fracture. Quantitative real-time polymerase chain reaction (PCR) was performed to determine the gene expression associated with inflammation and bone remodeling. The differences in the gene expression in bone tissues from the patients with early-stage cam-type FAI were also evaluated based on clinical parameters.

RESULTS

In all, 12 patients with early-stage cam-type FAI and six patients in the control group were included in this study. Compared to the control samples, the bone tissue samples from patients with FAI showed higher expression levels of interleukin-6 (IL-6), alkaline phosphatase (ALP), receptor activator of nuclear factor-kB ligand (RANKL), and osteoprotegerin (OPG) (P < 0.05). IL-1 expression was detected only in the control group. On the other hand, there was no significant difference in IL-8 expression between the patients with FAI and the control group. The patients with FAI having a body mass index (BMI) of >24 kg/m² showed higher ALP expression (P < 0.05). Further, the expression of IL-6 and ALP was higher in the patients with FAI in whom the lateral center-edge angle was >30° (P < 0.05).

CONCLUSIONS

Our results indicated the metabolic condition of bone tissues in patients with early-stage cam-type FAI differed from that of normal bone in the femoral head-neck junction. The expression levels of the genes associated with inflammation and bone remodeling were higher in the bone tissue of patients with early-stage cam-type FAI than in the patients with normal bone tissue.

Pediatric and Adolescent Figure Skating Injuries: A 15-Year Retrospective Review

OBJECTIVE

To analyze the characteristics of injuries sustained by young figure skaters who were evaluated at regional pediatric sports medicine clinics.

DESIGN

Retrospective chart review (2003-2017).

SETTING

Sports medicine clinics at a tertiary-level pediatric medical center.

PATIENTS

Two hundred ninety-four figure skaters (271 female and 23 male). Age rage: 9 to 19 years. Mean age: 14.2 ± 2.3 years.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Mechanism of injury (acute vs overuse), injured body areas, diagnoses for most commonly injured body areas, and distribution of bone stress injuries.

RESULTS

Eight hundred sixty-four figure skating-related injuries were identified. Approximately 68.9% were overuse and 31.1% were acute. In female figure skaters, the most frequently injured body areas were foot/ankle (29.6%), knee (19.3%), and back (15.8%). In male figure skaters, they were foot/ankle (25.4%), hip (16.4%), and knee (14.9%). Most common diagnoses at these body areas were tendinopathy (foot/ankle), extensor mechanism (knee), and posterior column bone stress injuries (back). All injuries to anterior knee structures, excluding bone contusions, were categorized as extensor mechanism injuries. About 11.8% of all injuries were bone stress reactions/fractures with the majority occurring at the back (42.2%), foot/ankle (32.4%), and lower leg (15.7%).

CONCLUSION

Most injuries sustained by figure skaters were overuse and occurred most commonly at the foot/ankle (29.6%), knee (19.3%), and back (15.8%). Approximately 1 in 10 injuries were bone stress reactions/fractures, and nearly 1 in every 3 skaters who presented with back pain was diagnosed with a posterior column bone stress injury. Health care providers who take care of young figure skaters need to maintain a high index of suspicion for overuse injuries, especially bone stress reactions/fractures.

Femoroacetabular Impingement and Acetabular Labral Tears - Part 1: Pathophysiology and Biomechanics

Femoroacetabular impingement (FAI) is an important cause of hip pain, and the main etiology of hip osteoarthritis in the young population. Femoroacetabular impingement is characterized by subtle alterations in the anatomy of the acetabulum and proximal femur, which can lead to labrum tearing. The acetabular labrum is essential to the stability of the hip joint. Three types of FAI were described: cam (anespherical femoral head), pincer (acetabular overcoverage) and mixed (characteristics of both cam and pincer). The etiology of FAI is related to genetic and environmental characteristics. Knowledge of this condition is essential to adequately treat patients presenting with hip pain.

Return to Sports After Joint Preservation Hip Surgery

Femoroacetabular impingement results from a mismatch of congruency between the femoral head and the acetabulum. This condition is most common among young, active patients and may lead to pain, decreased quality of life, and inability to participate in athletics. Hip preservation surgery is widely performed is used as a definitive treatment option in athletes at all levels of competition. Athletes have reported high rates of return to play and satisfaction and expect rehabilitation to require approximately 4 to 6 months. This article provides an overview of femoroacetabular impingement, including diagnosis and treatment, with focus on athletes and return to play.

Young elite Alpine and Mogul skiers have a higher prevalence of cam morphology than non-athletes

PURPOSE

To investigate the prevalence of cam morphology in (1) a group of young elite Mogul and Alpine skiers compared with non-athletes and (2) between the sexes.

METHOD

The hip joints of 87 subjects [n = 61 young elite skiers (29 females and 32 males) and n = 26 non-athletes (17 females and 9 males)] were examined using MRI, for measurements of the presence of cam morphology (α-angle ≥ 55).

RESULTS

The skiers had a significantly higher prevalence of cam morphology compared with the non-athletes (49% vs 19%, p = 0.009). A significant difference (p < 0.001) was also found between females and males, where 22% of the females and 61% of the males had cam morphology. Among the skiers, there was also a significant difference (p < 0.001) between the sexes, where 28% of the females and 68% of the males had cam morphology. This difference between the sexes was not found in the non-athletic group. No significant differences were found between Mogul and Alpine skiers.

CONCLUSION

Young male elite skiers have a higher prevalence of cam morphology of the hips compared with non-athletes.

LEVEL OF EVIDENCE

II.

Metabolic and Hemodynamic Results and Early Complications in Simultaneous Bilateral versus Unilateral Hip Arthroscopy

Background

To compare the hemodynamic parameters—electrolyte concentration, D-dimer level, creatine phosphokinase level—and the incidence of early complications of simultaneous bilateral versus unilateral hip arthroscopy.

Methods

A prospective study was conducted on patients (> 18 years of age) undergoing unilateral or bilateral hip arthroscopy under the same anesthetic between 2013 and 2015. Patients were followed up for 30 days after surgery. In all cases, data were collected before, during, and after the surgical procedure.

Results

One hundred cases of hip arthroscopy (51 unilateral and 49 bilateral) were included in this study. There was a greater variation in systolic blood pressure and heart rate in the unilateral group. The sodium levels were higher in the bilateral group with an adjusted mean difference of 5.31 mmol/L (p < 0.001). During the first 24 hours after the procedure, the proportion of patients with an altered D-dimer of > 500 ng/mL was 85.7% in the bilateral group and 56.9% in the unilateral group. There was no significant difference in the incidence of complications between the groups (bilateral, 8.2%; unilateral, 9.8%; crude odds ratio, 0.83; 95% confidence interval, 0.24 to 2.92; p = 0.526).

Conclusions

The variations of hemodynamic parameters in patients undergoing hip arthroscopy remained within normal ranges. The findings of this study suggest that bilateral hip arthroscopy be selected according to the patient's condition, considering that the risk of complications and metabolic alterations in bilateral hip arthroplasty are similar to those in unilateral arthroscopy.

The clinical presentation, diagnosis and pathogenesis of symptomatic sports-related femoroacetabular impingement (SRFAI) in a consecutive series of 1021 athletic hips

AIM

To examine the pathogenesis and clinical presentation of sports-related femoroacetabular impingement (SRFAI) in a large consecutive series of symptomatic athletes.

METHODS

Between January 2009 and February 2017 prospectively collected data from competitive athletes within the Gaelic Athletic Association (GAA), and who subsequently underwent arthroscopic treatment for symptomatic FAI, were analysed. Data was collected using internationally validated health questionnaires (Harris Hip Score, UCLA, SF-36, WOMAC) and recognised clinical (ROM, symptom presentation, provocation tests) and radiological (AP pelvis, Dunn, False profile) indicators/measures of FAI.

RESULTS

A total of 1021 consecutive cases (mean 26.6 ± 6.2 years) were included. In every case, conservative treatment failed to resolve symptoms with athletes attending an average of 2.4 ± 1.1 health care professionals prior to referral. Symptoms developed gradually (78%) and consisted primarily of groin pain (76.1%) and hip stiffness (76.5%) following activity. An acetabular rim deformity (pincer) was present in all cases; a cam deformity in 72.1%. The prevalence and degree of cam deformity increased with progressing age groups (p < 0.001); mean lateral centre-edge angle remained static (p = 0.456). Increasing CEA, alpha angle and presence of rim fracture was associated with a reduction in all ranges of hip movement (p < 0.001).

CONCLUSION

Symptomatic SRFAI presented in this large series of GAA athletes failed to resolve with non-operative treatment. Increasing hip deformity resulted in poorer ROM. Abnormal acetabular morphology remains static with increasing athletic age while cam deformity is progressive and most likely a secondary pathology.

Management of femoroacetabular impingement syndrome: current insights

Since the description of femoroacetabular impingement (FAI) by Ganz in 2003, our understanding of the pathophysiology, management options, and outcomes has evolved and literature continues to be generated on this condition at a rapid rate. FAI has been identified as a primary source of hip pain as well as a generator of secondary osteoarthritis. Improvements in the radiographic detection of cam and pincer morphologies as well as a better understanding of the structural impact of these morphologies have led to improved preoperative planning. Advancements in hip arthroscopy techniques have also led to a higher rate of arthroscopic management of this condition over the initially described open surgical dislocation technique. While arthroscopic management of this condition has become the most common form of surgical management for FAI, inadequate bony resection has been shown to be a frequent source of revision surgery. Therefore, roles for open surgical dislocation and combined mini-open approaches remain, particularly in cases where concern for the inability to fully access the morphology arthroscopically exists.

The effect of suprainguinal fascia iliaca block on the recovery of patients after arthroscopic hip surgery

BACKGROUND

Adolescent and young adult patients undergoing arthroscopic hip surgery experience significant pain in the immediate postoperative period. There is a small body of evidence that indicates suprainguinal fascia iliaca blocks can improve comfort during recovery from this intervention. Our hypothesis was that patients undergoing hip surgery would consume fewer opioids and have less pain in the perioperative time frame if they received the block as part of their analgesic regimen.

METHODS

In this study, we evaluated the outcomes of 716 patients, including 275 who received a suprainguinal fascia iliaca block, and 441 who did not have a block. Inclusion criteria included all age groups and American Society of Anesthesiologists, functional classes 1-2. Patients who received other concurrent procedures or those with incomplete data sets were excluded. We utilized a regional anesthesia database that combined data from various repositories into one web-based relational system. The primary outcomes were total opioid consumption and pain scores in the recovery room. Secondary outcomes included opioid side effects, block-related complications, and total recovery room time. Multivariable logistic regression analysis was used to evaluate opioid consumption, side effects, and total recovery times. Pearson chi-square was applied to assess the level of pain between the two groups.

RESULTS

Total opioid consumption was significantly less in the block group compared to those not receiving a block (0.28 mg/kg vs 0.35 mg/kg, P < 0.001, 95% CI of difference in medians 0.04-0.10 mg/kg), but there was no statistical difference in pain scores. Patients with the regional block had a lower frequency of emesis in the PACU (0.7% vs 4.3%; P < 0.005, 95% CI of difference: 2-25) and shorter PACU times (93 vs 108 minutes, P < 0.001, 95% CI of difference: 8-23 minutes).

CONCLUSION

Our study supports the clinical effectiveness of suprainguinal fascia iliaca blocks in young patients undergoing arthroscopic hip surgery.

Etiology and Pathomechanics of Femoroacetabular Impingement

PURPOSE OF REVIEW

Femoroacetabular impingement is a common cause of hip pain in young patients and has been shown to progress to osteoarthritis. The purpose of this review is to better understand the development of femoroacetabular impingement.

RECENT FINDINGS

Recent literature shows little genetic transmission of FAI. However, molecular studies show strong similarities with the cartilage in osteoarthritis. The development of cam lesions has a strong association with sports participation, particularly at the time of physeal closure suggesting abnormal development. Lumbar, pelvis, and femoral biomechanics may also play an important role in dynamic impingement. In summary, femoroacetabular impingement is a dynamic process with many influences. Further research is needed to clarify the pathophysiology of FAI development in hopes of finding preventative options to reduce symptoms and progression to osteoarthritis.

Editorial Commentary: Femoroacetabular Impingement and Open Physes-To Operate or Not to Operate? Is That the Only Question?

Our clinical understanding, diagnosis, and treatment of femoroacetabular impingement (FAI) have improved tremendously over the past 2 decades. However, we still have major questions to answer when it comes to the exact etiology of FAI and the role played by intense adolescent athletic activity in the development of FAI. In a society in which there is increasing sports specialization in young people and also rising rates of overuse injuries, the balance between surgical intervention and early preventive measures has yet to be clearly defined. Although we may be able to "safely" treat FAI surgically and provide clinical improvement for these patients, the question remains: Are we addressing with surgery a condition that could be prevented with earlier precautionary measures? It is our responsibility to answer that question for our patients.

Bilateral Hip Arthroscopy: Can Results From Initial Arthroscopy for Femoroacetabular Impingement Predict Future Contralateral Results?

PURPOSE

To determine the degree of correlation of radiographic measurements, degree of correlation of intraoperative pathology, and difference in outcomes between sides of patients requiring staged bilateral hip arthroscopy.

METHODS

Two high-volume hip preservation centers retrospectively reviewed hip preservation databases for staged bilateral hip arthroscopies conducted between 2008 and 2015. Patients were separated into those who presented with bilateral hip pain and those that presented with unilateral pain and developed contralateral pain >2 years later. Patients were analyzed for radiographic correlation (alpha angle, lateral center edge angle, anterior center edge angle, magnetic resonance imaging alpha angle, Tönnis grade) and correlation of intraoperative pathology (acetabular labrum articular disruption grade, Outerbridge grade/location, Villar class ligamentum teres tears, labral tear location, symmetry of Seldes tear types, and the differences between operative procedures). Patient-reported outcomes were analyzed (modified Harris Hip Score, Non-Arthritic Hip Score, International Hip Outcome Tool-12, hip outcome score-sport specific subscale, visual analog scale, patient satisfaction). Correlative tests included Pearson and Spearman; univariate and multivariate analysis for differences included χ-square test and Student t tests for ordinal and continuous variables respectively.

RESULTS

A total of 133 of 2,705 patients (4.6%) underwent bilateral hip arthroscopy. Radiographic alpha angle, magnetic resonance imaging alpha angle, lateral center edge angle, and anterior center edge angle demonstrated strong correlation (Pearson's coefficients 0.651, 0.648, 0.644, 0.667, respectively, P < .0001). Tönnis grade was weakly correlated (Pearson's coefficient 0.286, P = .001). Intraoperative pathology was moderately correlated (Pearson's coefficients for acetabular Outerbridge location, 0.300, P = .0170; acetabular labrum articular disruption, 0.490, P < .0001; acetabular Outerbridge; 0.530; P < .0001; femoral head Outerbridge, 0.459, P < .0001; Villar class, 0.393, P < .0001; and labral tear location, 0.468, P < .0001). Labral tear Seldes type was compared with Bowker's symmetry test and there was no significant difference between sides. There were no significant differences in surgical interventions performed between sides. Patients with bilateral hip arthroscopies significantly improved in all measured patient-reported outcomes and had a high patient satisfaction after both procedures. Final patient-reported outcomes and change in patient-reported outcomes were not different between procedures; follow up ranged from 3 months to 8 years.

CONCLUSIONS

This study demonstrated an incidence of 4.6% of patients who require bilateral hip arthroscopy. These patients can expect significant improvement after surgical intervention. Patients that had 1 side done gained similar improvement when the contralateral side was performed. Preoperative radiographic, intraoperative pathology, and procedures performed were similar between hips.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Higher Prevalence of Concomitant Shoulder Labral Tears in Patients With Femoroacetabular Impingement

PURPOSE

To examine the prevalence of concomitant symptomatic glenoid labral tears in patients with femoroacetabular impingement (FAI) in comparison to a control group of patients undergoing anterior cruciate ligament (ACL) reconstruction.

METHODS

We retrospectively identified 1,644 patients who underwent femoroacetabular osteoplasty (FAO) and labrum repair from January 2007 to September 2016 and 1,055 patients who underwent arthroscopic ACL reconstruction from January 2012 to December 2014, which acted as our control group. An electronic questionnaire, including 8 questions regarding history of shoulder pathology, was sent to all patients in both groups. Symptomatic shoulder labral tears were identified on the basis of a positive magnetic resonance imaging scan or history of labral repair by reviewing patients' medical records and the filled questionnaire. Continuous variables were compared by use of a Mann-Whitney U test, and categorical variables were compared using Fisher's exact test. The Holm-Bonferroni sequential correction method was used to adjust P values for multiple comparisons of the presence of shoulder pathology.

RESULTS

A total of 443 patients (405 cam lesion) in the FAO group and 307 patients in the ACL reconstruction group completed the prepared questionnaire and were included in the study. Patients in the FAO group were slightly older (36.3 years [range, 15.4-61.7] vs 32.3 years [range, 16.3-75.7]) and more commonly female in the FAO group (58.0%, n = 257) compared with those in the ACL group (48.9%, n = 150). The prevalence of shoulder labral tear was 12.0% (95% confidence interval [CI], 9.3%-15.3%) for the FAO group compared with only 3.3% (95% CI, 1.8%-5.9%) for the ACL group. This represents a 3.7-fold (95% CI, 1.9-7.1) increase in the risk of shoulder labral tear for patients in the FAO group. Furthermore, shoulder labral tears were reported to be traumatic in only 43.4% of patients in the FAO group compared with 80.0% of patients in the ACL group. A similar proportion of patients in both groups (66.0% for FAO vs 60.0% for ACL) underwent a shoulder labral repair procedure.

CONCLUSION

There appears to be an association between acetabular labral tear caused by FAI and shoulder labral lesions. Patients in the FAI group had a 3.7-fold increase in the risk of shoulder labral tear compared with the ACL group. Future studies are needed to examine a possible cause behind the current findings.

LEVEL OF EVIDENCE

Level III, comparative trial study.

Prevalence of femoroacetabular impingement and effect of training frequency on aetiology in paediatric football players

PURPOSE:

The aim of this study was to determine the prevalence of asymptomatic radiographic findings of femoroacetabular impingement (FAI) in paediatric football players in different age groups and to investigate aetiological factors.

METHODS:

Paediatric male athletes between 10 and 17 years of age from 8 soccer teams were recruited. In addition to an annual control check-up, anteroposterior pelvis and frog-leg radiographs as well as the curriculum vitae of the athletes, their injuries, and real-time complaints were recorded. The alpha angle, lateral centre-edge angle, Tönnis angle, and collodiaphyseal angle were measured and morphological abnormalities were noted.

RESULTS:

There were 214 male football players with a mean age of 13.4 ± 3.2 years included in the study. In the morphological analysis of hips, there was FAI in 30% of the athletes. In the analysis of FAI prevalence in 3 subgroups based on age (Group 1: 10-12 years [ n = 25], Group 2: 13-15 years [ n = 104], Group 3: 16-17 years [ n = 85]), there was 0% FAI in Group 1, 19.1% in Group 2 and 60% in Group 3. In the analysis of aetiological factors, there was no significant difference between the right and left hips of players regarding alpha angles and FAI prevalence. However, the prevalence of FAI was higher in players who had been playing football for 3 years or more and who had been training for 12.5 hours/week or more.

CONCLUSION:

Training for 12.5 hours or more per week in paediatric football players doubled the risk development of FAI morphology.

A systematic review of surgical methods to restore articular cartilage in the hip

This systematic review examines the current literature regarding surgical techniques for restoring articular cartilage in the hip, from the older microfracture techniques involving perforation to the subchondral bone, to adaptations of this technique using nanofractures and scaffolds. This review discusses the autologous and allograft transfer systems and the autologous matrix-induced chondrogenesis (AMIC) technique, as well as a summary of the previously discussed techniques, which could become common practice for restoring articular cartilage, thus reducing the need for total hip arthroplasty. Using the British Medical Journal Grading of Recommendations, Assessment, Development and Evaluation (BMJ GRADE) system and Grade system. Comparison of the studies discussed shows that microfracture has the greatest quantity and quality of research, whereas the newer AMIC technique requires more research, but shows promise.

Cite this article: W. E. Hotham, A. Malviya. A systematic review of surgical methods to restore articular cartilage in the hip. Bone Joint Res 2018;7:336–342. DOI: 10.1302/2046-3758.75.BJR-2017-0331.

Influence of evolution on cam deformity and its impact on biomechanics of the human hip joint

Anatomy and biomechanics of the human hip joint are a consequence of the evolution of permanent bipedal gait. Habitat and behaviour have an impact on hip morphology and significant differences are present even within the same biological family. The forces acting upon the hip joint are mainly a function of gravitation and strength of the muscles. Acetabular and femoral anatomy ensure an inherently stable hip with a wide range of motion. The femoral head in first human ancestors with upright gait was spherical (coxa rotunda). Coxa rotunda is also seen in close human relatives (great apes) and remains the predominant anatomy of present-day humans. High impact sport during adolescence with open physis however can activate an underlying genetic predisposition for reinforcement of the femoral neck, causing an epiphyseal extension and the formation of an osseous asphericity at the antero-superior femoral neck (cam deformity). The morphology of cam deformity is similar to the aspherical hips of quadrupeds (coxa recta), with the difference that in quadrupeds the asphericity is posterior. It has been postulated that this is due to the fact that humans bear weight on the extended leg, while quadrupeds bear weight at 90-100° flexion. The asphericity alters the biomechanical properties of the joint and as it is forced into the acetabulum leading to secondary cartilage damage. It is considered a risk factor for later development of osteoarthritis of the hip. Clinically this presents as reduced range of motion, which can be an indicator for the structural deformity of the hip. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:XX-XX, 2018.

Origin of Cam Morphology in Femoroacetabular Impingement

Cam morphology of the proximal femur is an abnormal contour of the femoral head-neck junction present in approximately 15% to 25% of the asymptomatic population, predominantly in males. Alpha angle and femoral head-neck offset ratio are 2 objective measurement tools that define cam morphology. Both primary (idiopathic) and secondary cam deformity develops through distinct mechanisms. The cause of primary (idiopathic) cam morphology remains incompletely understood. Mounting evidence suggests that idiopathic cam morphology develops during adolescence through alterations in the capital femoral epiphysis in response to participation in vigorous sporting activity. While the exact cause of epiphyseal extension has not yet been determined, preliminary evidence suggests that epiphyseal extension may reflect a short-term adaptive response to provide stability to the physis at the long-term cost of the development of cam morphology. Commonly recognized causes of secondary cam deformity include frank slipped capital femoral epiphysis, Legg-Calve-Perthes disease, and deformity after fracture of the proximal femur. Recent studies also support subtle slipped capital femoral epiphysis as a unique and silent cause of a small percentage of subjects previously thought to have idiopathic cam deformity.

Femoroacetabular Impingement: A Review

Femoroacetabular impingement (FAI) is one of the most researched conditions in sports medicine today. FAI occurs due to abnormal morphology and subsequently contact between the proximal femur and the acetabulum. With repetitive loading, this femoroacetabular mismatch can be a source of labral and chondral injuries. FAI is more prevalent in the athletic population, particularly those athletes who participated in high level activities at a younger age. If nonoperative management is failed, surgical treatment is often done arthroscopically and with good results. This review attempts to provide an overview of the pathophysiology, diagnosis, and potential treatment options of FAI with a focus on the most recent literature.

Prevalence of asymptomatic femoroacetabular impingement in Turkey; cross sectional study

OBJECTIVES

Femoroacetabular impingement (FAI) is one of the causes of hip pain in young-adult patients. The purpose of our study is to determine the prevalence of radiological FAI findings in asymptomatic population in Turkey.

METHODS

Trauma patients aged 18-65 years who applied to the emergency service between September 2015 and September 2016 were retrospectively evaluated for this study. After a preliminary study and power analysis, 2152 hips of the 1076 previously asymptomatic patients were evaluated radiologically with pelvis antero-posterior and frog-leg radiographs. On radiographs of these patients; alpha angle, lateral central edge angle (LCEA), Tönnis angle (TA) and collodiaphyseal angle were measured. Alpha angle values higher than 55° were noted as cam type FAI. TA values lower than 0° or LCEA values higher than 39° were noted as pincer type FAI. LCEA values lower than 25° or TA values higher than 10° were noted as acetabular dysplasia.

RESULTS

Mean age of 1076 patients (602 female, 474 male) was 42.1 ± 15.6 years. The assessment showed that 15.9% of the patients had cam type, 10.6% had pincer type, 3.1% had combined type FAI and 9.3% had findings of acetabular dysplasia. The prevalence of asymptomatic FAI is significantly more in males (46%) in comparison to females (17%) in Turkey.

CONCLUSION

Even though FAI is considered to be a pathology associated with hip osteoarthritis; it is very common in asymptomatic population. In this respect, our study showed that prevalence of radiological FAI findings in asymptomatic adult population was 29.6% in Turkey.

Cam Deformities and Limited Hip Range of Motion Are Associated With Early Osteoarthritic Changes in Adolescent Athletes: A Prospective Matched Cohort Study

BACKGROUND

The natural history of femoroacetabular impingement (FAI) remains incompletely understood. In particular, there is limited documentation of joint damage in adolescent patients with limited range of motion (LROM) of the hip, which is commonly associated with FAI.

PURPOSE

To evaluate changes in magnetic resonance imaging (MRI), radiographs, and clinical examinations over 5 years in a group of athletes from a wide variety of sports with asymptomatic LROM of the hip compared with matched controls.

STUDY DESIGN

Cohort study (prognosis); Level of evidence, 2.

METHODS

The authors screened 226 male and female athletes aged 12 to 18 years presenting for preparticipation sports physical examinations. Using a goniometer, we identified 13 participants with at least one hip having internal rotation <10° with the hip flexed to 90°. Overall, 21 of 26 hips (81%) had internal rotation <10°. These participants were age- and sex-matched to 13 controls with internal rotation >10°. At the time of enrollment, all participants were asymptomatic and underwent a complete hip examination and radiographic imaging with radiographs (anteroposterior [AP] and von Rosen views) and non-arthrogram MRI. Participants returned at 5-year follow-up and underwent repeat hip examinations, imaging (AP and lateral radiographs and non-arthrogram MRI), and hip function questionnaires. MRI scans were classified as "normal" versus "abnormal" based on the presence of any of 13 scored chondral, labral, or osseous abnormalities. Comparisons between the LROM group and control group were performed using generalized linear models (either linear, logistic, or log-binomial regression as appropriate for the outcome) with generalized estimating equations to account for the within-participant correlation due to patients having both hips included. Relative risk (RR) estimates are reported with 95% CIs.

RESULTS

At the time of study enrollment, 16 of 26 hips (62%) in the LROM group had abnormal MRI findings within the acetabular labrum or cartilage compared with 8 of 26 hips (31%) in the control group (RR, 2.0; 95% CI, 0.95-4.2; P = .067). The mean alpha angle measured from radial MRI sequences was 58° in the LROM group versus 44° in the control group ( P < .0001). In the LROM group, 13 of 26 hips (50%) had a positive anterior impingement sign, whereas 0 of 26 hips (0%) had a positive anterior impingement sign in the control group. At 5-year follow-up, 18 of 19 hips (95%) in the LROM group had abnormal MRI findings compared with 14 of 26 hips (54%) in the control group (RR, 1.7; 95% CI, 1.1-2.7; P = .014). New or progressive findings were documented on MRI in 15 of 20 hips in the LROM group compared with 8 of 26 hips in the control group (RR, 2.4; 95% CI, 1.2-4.8; P = .011). Six of 22 hips (27%) in the LROM group progressed from Tönnis grade 0 to Tönnis grade 1 in degenerative changes, whereas all 26 hips in the control group remained at Tönnis grade 0 on hip radiographs. In the LROM group, 11 of 22 hips (50%) had a positive anterior impingement sign, whereas 1 of 26 hips (4%) had a positive anterior impingement sign in the control group. A cam deformity (alpha angle >55° on lateral radiographs) was present in 20 of 22 hips (91%) in the LROM group and 12 of 26 hips (46%) in the control group ( P = .0165). The following variables at baseline were associated with an increased risk of degenerative changes at 5-year follow-up for the entire cohort: decreased hip internal rotation, positive anterior impingement sign, decreased hip flexion, increased alpha angle, and presence of a cam lesion.

CONCLUSION

At 5 years, young athletes with LROM of the hip showed increased progressive degenerative changes on MRI and radiographs compared with matched controls. Although the majority of these participants remained asymptomatic, those with features of FAI had radiographic findings consistent with early osteoarthritis. These outcomes suggest that more aggressive screening and counseling of young active patients may be helpful to prevent hip osteoarthritis in those with FAI.

Imaging of impingement syndromes around the hip joint

Impingement syndromes are increasingly recognised as significant causes of hip pain and dysfunction. A broad spectrum of intraarticular and extraarticular conditions has been implicated in their pathophysiology. Physical examination is often inconclusive as clinical findings may be unclear or misleading, often simulating other disorders. With current improvements in imaging techniques and better understanding of hip impingement related pathomechanisms, these entities can be accurately diagnosed. In addition, preoperative imaging has allowed for targeted treatment planning. This article provides an overview of the various types of hip impingement, including femoroacetabular impingement, ischiofemoral impingement, snapping hip syndrome, greater trochanteric-pelvic and subspine impingement. Current literature data regarding their pathogenesis, clinical manifestation and imaging work-up are discussed.

The Etiology of Cam-type Femoroacetabular Impingement: A Cadaveric Study

BACKGROUND

There is a dearth of literature examining the causes of cam-type femoroacetabular impingement (FAI) and when such morphology appears. The purpose of the current study was to analyze how the ossific portion of the proximal femur develops over time with respect to standard cam-type FAI parameters.

METHODS

A collection of 193 femurs from cadavers aged 4 to 21 years were evaluated. The age, sex, ethnicity, and status of the proximal femoral physes (open or closed) of each were recorded. Each specimen was digitally photographed in standardized anteroposterior and modified axial positions. From these photographs, the anterior offset, anterior offset ratio (AOR), and α-angle were determined. A cam lesion was defined as an α-angle >55 degrees on the lateral view.

RESULTS

The mean age of the specimens was 17.5±4.2 years. The majority were male (69%) and African American (79%) with closed physes (78%). There were significant differences among discrete age groups with respect to α-angle (P=0.01), anterior offset (P<0.01), and AOR (P<0.01). In addition, younger femurs with open physes had a significantly higher mean α-angle (P<0.01), lower mean anterior offset (P<0.01), and higher mean AOR (P<0.01) compared with older ones with closed physes. Specimens defined as having a cam deformity had a statistically higher α-angle (P<0.01) and lower anterior offset (P<0.01), but there was no difference in AOR values compared with specimens without a cam lesion (P=0.1).

CONCLUSIONS

The apparent decline in α-angles as age increases indicates that the traditional α-angle in younger patients measures a different anatomic parameter (ossified femur excluding the cartilaginous portion) than in older patients (completely ossified femur). This suggests that the bony α-angle is inappropriate in the evaluation of cam lesions in the immature physis. The AOR, rather than the anterior offset, may be more accurate in the evaluation of the growing proximal femur.

CLINICAL RELEVANCE

This study provides novel insight into, and enhances the understanding of, the development of cam-type FAI.

Hip Pain and Mobility Deficits-Hip Osteoarthritis: Revision 2017

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to hip pain and mobility deficits. J Orthop Sports Phys Ther. 2017;47(6):A1-A37. doi:10.2519/jospt.2017.0301.

Hip Imaging in Athletes: Sports Imaging Series

Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016.

Prevalence of cam hip shape morphology: a systematic review

OBJECTIVE

Cam hip shape morphology is a recognised cause of femoroacetabular impingement (FAI) and is associated with hip osteoarthritis. Our aim was to systematically review the available epidemiological evidence assessing the prevalence of cam hip shape morphology in the general population and any studied subgroups including subjects with and without hip pain.

DESIGN

All studies that reported the prevalence of cam morphology, measured by alpha angles, in subjects aged 18 and over, irrespective of study population or presence of hip symptoms were considered for inclusion. We searched AMED, MEDLINE, EMBASE, CINAHL and CENTRAL in October 2015. Two authors independently identified eligible studies and assessed risk of bias. We planned to pool data of studies considered clinically homogenous.

RESULTS

Thirty studies met inclusion criteria. None of the included studies were truly population-based: three included non-representative subgroups of the general population, 19 included differing clinical populations, while eight included professional athletes. All studies were judged to be at high risk of bias. Due to substantial clinical heterogeneity meta analysis was not possible. Across all studies, the prevalence estimates of cam morphology ranged from 5 to 75% of participants affected. We were unable to demonstrate a higher prevalence in selected subgroups such as athletes or those with hip pain.

CONCLUSIONS

There is currently insufficient high quality data to determine the true prevalence of cam morphology in the general population or selected subgroups. Well-designed population-based epidemiological studies that use homogenous case definitions are required to determine the prevalence of cam morphology and its relationship to hip pain.

Etiology of Femoroacetabular Impingement in Athletes: A Review of Recent Findings

The relationship between hip deformities and osteoarthritis has recently received a lot of attention. In particular, it has been shown that both osteoarthritis and its precursors, such as the hip deformities that lead to femoroacetabular impingement (FAI), are more prevalent in elite athletes compared with the general population. However, the etiology of the above-mentioned types of hip deformity is not currently well understood. Many recent studies have attempted to shed light on the etiology of this disease. In this article, the main clinical, radiological, mechanobiological, and biomechanical findings of relevance to understanding the etiology of hip deformities leading to FAI are reviewed. Based on these findings, a consistent biomechanical theory explaining the development of hip deformities in athletes is then presented. According to the presented theory, the repetitive, impact-like musculoskeletal loads that athletes experience, particularly when they undertake extreme ranges of hip motion, cause the development of hip deformities. According to this theory, these musculoskeletal loads trigger abnormal growth patterns during the years of skeletal development and cause the formation of hip deformities. A number of hypotheses based on the proposed theory are then formulated that could be tested in future studies to ascertain whether the proposed theory could sufficiently describe the development of hip deformities in athletes.

Prevalence of Cam-Type Morphology in Elite Ice Hockey Players

BACKGROUND

Femoroacetabular impingement (FAI) has been increasingly recognized as a cause of hip pain in athletes at all levels of competition, specifically ice hockey players.

PURPOSE/HYPOTHESIS

The purpose of this study was to define the prevalence of cam and pincer radiographic deformity in elite ice hockey players. The hypothesis was that elite hockey players will have a higher prevalence of radiographic hip abnormalities compared with the general population.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Anteroposterior and frog-leg lateral radiographs on 137 elite ice hockey players were prospectively obtained during the 2014-2015 preseason entrance examinations. Study participants included National Hockey League roster players as well as the respective farm team members. Demographic data were collected, including age, position, shooting side, and any history of hip pain or hip surgery. Patients with a history of hip surgery were excluded from the analysis. A single sports medicine fellowship-trained orthopaedic surgeon used standard radiographic measurements to assess for the radiographic presence of cam or pincer deformity. Radiographs with an alpha angle ≥55° on a frog-leg lateral view were defined as cam-positive. Each participant underwent a preseason physical examination with an assessment of hip range of motion and impingement testing.

RESULTS

A total of 130 elite ice hockey players were included in the analysis; 180 (69.4%) hips met radiographic criteria for cam-type deformity. The prevalence in right and left hips was 89 (69.5%) and 91 (70.0%), respectively; 70 (60.8%) players demonstrated bilateral involvement. Hips with cam deformity had a mean alpha angle of 67.7° ± 8.3° on the right and 68.9° ± 9.0° on the left. Of the patients with alpha angles ≥55°, 5.6% (5/89) had a positive anterior impingement test of the right hip, while 11% (10/91) had positive anterior impingement test of the left. Players with radiologic cam deformity had a statistically significant deficit in external rotation of the right hip, as well as in both internal and external rotation of the left hip, compared with those with normal alpha angles. When assessing for crossover sign, 64 of 107 (59.8%) had a positive radiographic finding. Forty-one players (38.3%) had evidence of a crossover sign of the right hip and 42 (39.3%) of the left. When comparing position players, goalies had the highest prevalence of cam-type deformity (93.8%) and the least acetabular coverage.

CONCLUSION

The study data suggest that elite ice hockey players have a significantly higher prevalence of radiographic cam deformity in comparison to what has been reported for the general population.

Femoroacetabular impingement in children and adolescents

PURPOSE OF REVIEW

The present review discusses the etiology, clinical presentation, and management of femoroacetabular impingement (FAI) in the pediatric population, including etiologic and diagnostic controversies, management options, and outcomes.

RECENT FINDINGS

New evidence demonstrates conflicting results regarding how and when primary FAI develops in relation to skeletal maturity. Recent studies also discuss the effects of sex, race, and sports on FAI development and radiographic considerations in the pediatric population. Recent literature demonstrates good to excellent outcomes in the operative management of FAI in children and adolescents.

SUMMARY

FAI is a source of pediatric hip pain and can occur primarily or secondarily. It is characterized by anterior hip pain, made worse with flexion activities, decreased hip internal rotation, and a positive impingement sign. Pathologic values for radiographic measures of FAI are not clearly defined in the pediatric population. As FAI is a risk factor for osteoarthritis, early intervention in specific patients may be indicated. Hip arthroscopy, surgical hip dislocation, or combined mini-open and arthroscopic approaches are utilized, with good to excellent short, and mid-term functional results. Further study is required in the pediatric population to identify potential preventive strategies, to delineate the pathologic radiographic values of FAI, to define specific indications for operative management, and to examine long-term outcomes to determine optimal management.

The Natural History of Femoroacetabular Impingement

Femoroacetabular impingement (FAI) is a clinical syndrome resulting from abnormal hip joint morphology and is a common cause of hip pain in young adults. FAI has been posited as a precursor to hip osteoarthritis (OA); however, conflicting evidence exists and the true natural history of the disease is unclear. The purpose of this article is to review the current understanding of how FAI damages the hip joint by highlighting its pathomechanics and etiology. We then review the current evidence relating FAI to OA. Lastly, we will discuss the potential of hip preservation surgery to alter the natural history of FAI, reduce the risk of developing OA and the need for future arthroplasty.

The Antiquity of the Cam Deformity: A Comparison of Proximal Femoral Morphology Between Early and Modern Humans

BACKGROUND

The precise etiology of cam impingement continues to be incompletely understood. The prevailing hypothesis posits that the deformity arises as a developmental injury prior to skeletal maturation. There is a possible evolutionary role, with an aspherical femoral head affording upright humans better stability. We set out to identify the antiquity of the cam deformity to better understand the comparative roles of modern behavior and evolution in its development.

METHODS

We used 249 physical specimens of femora from the Libben osteological collection, a set of bones from an ancient population who lived between the eighth and the eleventh century. These femora were photographed in four different orientations, and six specific proximal femoral angles were measured. The values were also compared with those from modern human femora using the Student t test, with a two-tailed p value of 0.05 denoting significance.

RESULTS

In total, 249 femora from 175 individuals were included in the final analysis. The ages of the individuals ranged between seventeen and fifty-five years. Interobserver and intraobserver correlation was good or excellent for all variables measured. Compared with modern populations, ancient human hips were significantly more anteverted (19.96° versus 12.85°; p < 0.001) and varus (true neck-shaft angle, 121.96° versus 129.23°; p < 0.001). The alpha angle was significantly lower in ancient humans (35.33° versus 45.61°; p < 0.001), and none of the ancient femora met the modern criteria for a cam deformity (an alpha angle of >50°).

CONCLUSIONS AND CLINICAL RELEVANCE

It appears that the cam deformity was nonexistent among ancient humans and is perhaps predominantly a product of modern-day stresses. Further clinical investigation into behavioral modifications in adolescence is warranted to potentially prevent the development of deformity and impingement.