Femoroacetabular Impingement Morphology Research Articles

Poster 199: High Prevalence of Elevated Beighton Scores in Females Undergoing FAI Surgery

Objectives: Femoroacetabular impingement (FAI) is classically described as restricted internal rotation in flexion resulting in labral and cartilage pathology. Despite 20 years of FAI research, there is still limited understanding of the drivers of symptomatology in the subset of patients with underlying FAI morphology. While the prevalence of FAI morphologies is substantially higher in men, numerous studies have shown more women being treated for FAI compared to men. Soft-tissue laxity and hip instability are increasingly recognized as a potential contributor to symptoms in addition to FAI. The Beighton score is a well-accepted means to quantify soft-tissue laxity and has been validated for self-scoring. The purpose of the current study was to (1) investigate the prevalence of soft-tissue laxity in male and female patients presenting with symptomatic FAI in a multicenter prospective cohort study, and (2) correlate soft-tissue laxity with patient primary complaints of either mobility, stability, or pain. Methods: A prospective multicenter cohort study of 696 FAI patients undergoing primary hip arthroscopy surgery was performed and utilized for the current study. Inclusion criteria are patients aged 14 to 45 years old with idiopathic FAI not caused by childhood disease. Exclusion criteria are previous ipsilateral hip procedures or disease processes such as neuromuscular disease or Tonnis 2 or greater osteoarthritis. The Beighton score was assessed by electronic patient self-scoring. Beighton scores >4 were considered a marker of soft-tissue laxity. The MSP index was utilized to have patients rank from most to least the biggest problems with their hip: Mobility (M), Stability (S), or Pain (P). The chi-square or Fisher exact test were utilized to compare groups. Results: The prevalence of Beighton scores >4 was 57.2% in female patients, compared to 29.3% in male patients (p < 0.001). In female patients, 44.4%, 22.6%, and 7.7% had Beighton scores of 5+, 7+, and 9 respectively, compared to 16.7%, 5.8%, and 1.8% in male patients (all p < 0.005). In the overall FAI cohort, pain was the primary complaint in 72.1% of patients, compared to 24.2% complaining primarily of mobility and 3.7% complaining primarily of stability. Among female patients, the presence of soft-tissue laxity (relative to thresholds of Beighton 4, 5, 7, and 9) did not significantly influence the patient primary complaints (with pain being the predominant complaint). Overall, 85 female patients had a Beighton score of 7 or greater and only 2.4% reported stability of the hip as a primary complaint, compared to 2.4% of female patients with a Beighton <7. Stability was more commonly indicated as a second most important factor in the setting of soft-tissue laxity, compared to mobility. Among female patients with a Beighton >7, 29.5% reported stability as a primary or secondary complaint, compared to 15.2% of female patients with a Beighton score <7. Conclusions: Over half of female patients undergoing FAI surgery have underlying soft-tissue laxity as measured by the Beighton score. In the setting of soft-tissue laxity, patient primary symptomatic complaint remains pain, but a secondary complaint is significant more likely to be stability rather than mobility (compared to FAI patients without soft tissue laxity complain of mobility secondarily over stability). Further research is needed to better understand the role of soft-tissue laxity in the pathophysiology of FAI and the outcomes of surgical treatment.

Femoroacetabular Variations Are Predisposing Factors for Traumatic Posterior Hip Dislocation.

Although high-energy trauma mechanisms are generally considered to cause traumatic posterior hip dislocations, femoroacetabular variations are assumed to contribute to low-impact hip dislocations. Thus, the present study aimed to identify morphologic femoral and acetabular risk factors that may also contribute to posterior hip dislocations in high-energy trauma mechanisms. The acetabular and femoral morphology of 83 hips with a traumatic posterior dislocation following a high-energy trauma mechanism were analyzed and matched to a control group of 83 patients who sustained high-energy trauma without a hip injury. The lateral center-edge angle, acetabular index, acetabular depth/width ratio, cranial and central acetabular version angles, and the anterior and posterior acetabular sector angles were measured on computed tomography to quantify femoroacetabular impingement (FAI) morphology, acetabular version, and coverage. The caput-collum-diaphyseal angle and the alpha angles in the coronal and axial planes were measured to detect cam-type FAI deformity. A receiver operating characteristic curve was utilized to determine threshold values for an increased risk of hip dislocation. Acetabular retroversion and posterior acetabular undercoverage were significantly increased in patients with hip dislocations compared with controls (p < 0.001). The central acetabular version angle and posterior acetabular sector angle that indicated an increased risk of hip dislocation were ≤9° and ≤90°, respectively. Cam-type FAI deformity and coxa valga were significantly increased in the dislocation group (p < 0.001). The anterolateral alpha angle that indicated an increased dislocation risk was ≥47°. Acetabular retroversion, posterior acetabular undercoverage, and cam-type FAI morphology may be risk factors contributing to traumatic posterior hip dislocation in high-energy trauma mechanisms. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

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.

Correction to: Prevalence of Cam-Type Femoroacetabular Impingement Morphology in the Hip Joints of Asymptomatic Thai Population

The author has informed the editor to correct the title, word, and reference in the article as follow: 1) Incorrect title in the article: Prevalence of Cam-Type Femoroacetabular Impingement Morphology in Hip Joint of Asymptomatic Thai Population Correct title: Prevalence of Cam-Type Femoroacetabular Impingement Morphology in the Hip Joints of Asymptomatic Thai Population 2) Incorrect word in page 2 of the article: This plane is parallel to the long axis of the femoral neck and passes through the center of the femoral neck, representing only the anterior contour of the femoral head-neck junction. Correct word: This plane is parallel to the long axis of the femoral neck and passes through the center of the femoral head, representing only the anterior contour of the femoral head-neck junction. 3) Incorrect reference in the article: 2. Leunig M, Ganz R. Femoroacetabular impingement. A common cause of hip complaints leading to arthrosis. Unfallchirurg 2005;108:9-10, 2-7. Correct reference: 2. Leunig M, Ganz R. Femoroacetabular impingement. A common cause of hip complaints leading to arthrosis. Unfallchirurg 2005;108:9-10, 12-7.

Characterizing the Residual SCFE Deformity: Utility of the 45-degree Dunn View.

After treatment with in situ stabilization, slipped capital femoral epiphysis (SCFE) patients have variable degrees of deformity that can contribute to femoroacetabular impingement (FAI). To evaluate the severity of residual deformity most physicians currently use biplanar radiographs of an anteroposterior pelvis which profiles the lateral head-neck deformity and a frog lateral view which profiles the anterior head-neck deformity. However, the assessment of FAI morphology commonly relies on the 45-degree Dunn view to profile the anterolateral head-neck junction where FAI deformity is maximal. Therefore, the purpose of this study was to compare the magnitude of residual SCFE deformity detected on the frog lateral radiograph to the 45-degree Dunn radiograph. A retrospective review of radiographic images of 50 hips (47 patients) diagnosed with SCFE at a single academic institution from 2014 to 2018 was performed. The group included 25 hips evaluated postoperatively after fixation (Group 1) and 25 hips presenting with residual symptomatic SCFE deformity after previous pinning (Group 2). The alpha angle was assessed on both the 45-degree Dunn and frog lateral views for comparison. The modified Southwick slip angle was assessed on the frog lateral view only as a measure of SCFE severity. The Dunn view showed the maximal residual SCFE deformity as measured by the alpha angle in 88% (44/50) of cases. Overall, the mean alpha angle (70.7 degree vs. 60.1 degree, P <0.001) was significantly larger on the Dunn view as compared with frog lateral. Subgroup analysis showed a larger alpha angle on Dunn view compared with frog lateral in both immediate postoperative and residual SCFE deformities as well: Group 1 (69.5 degree vs. 60.9 degree, P <0.001) and Group 2 (71.9 degree vs. 59.3 degree, P <0.001). In patients with SCFE, the maximal residual deformity of the proximal femur can typically be seen on the 45-degree Dunn view, rather than on the frog lateral view. Our findings suggest the 45-degree Dunn view may be beneficial part of the postoperative assessment of SCFEs to quantify the true maximal deformity present. Level IV.

Prevalence of Cam-Type Femoroacetabular Impingement Morphology in Hip Joint of Asymptomatic Thai Population

Objective: To determine the prevalence of cam-type femoroacetabular impingement (FAI) in the hip joints of asymptomatic Thai individuals using increased alpha angle of more than 55° on computed tomography (CT) images. Materials and Methods: The prospective study was conducted between 2019 and 2021. CT images of the 226 hip joints with no history of hip pain within three months prior to CT, no history of congenital dysplasia, Perthes disease, slipped capital femoral epiphysis, hip fracture, hip surgery, and inflammatory arthropathy, negative anterior impingement test, and no CT findings of osteoarthritis were evaluated. Alpha angles were measured in the axial oblique and radial planes at 12 o’clock, 1 o’clock, 1:30 o’clock, 2 o’clock, and 3 o’clock. Alpha angles of more than 55° were considered cam-type FAI morphology. Results: The prevalence rates of cam-type FAI morphology using increased alpha angles of more than 55° measured on axial oblique and radial plane images at 12 o’clock, 1 o’clock, 1:30 o’clock, 2 o’clock, and 3 o’clock were 0.4%, 0%, 4.9%, 8.4%, 8.0%, and 1.8% respectively. Cam-type morphology was common in the anterosuperior aspect of the femoral head-neck junction. The prevalence of cam-type morphology was significantly higher in men than in women. Conclusion: The range of prevalence rates of cam-type FAI morphology are between 0 to 8.4%. The prevalence is different in each image plane and location of the femoral head-neck junction. The prevalence of cam-type morphology in the present study differed from those in the previous studies conducted in other countries, which may be caused from variations in race and ethnicity. Keywords: Prevalence; Cam-type Femoroacetabular Impingement (FAI); Alpha angle; Computed tomography (CT)

Predictors of Achieving the Maximal Outcome Improvement Threshold for Willingness to Undergo Revision Hip Arthroscopy

Background: The maximal outcome improvement threshold for willingness to undergo revision hip arthroscopy (MOWT) has not been defined yet. Purpose: To determine the percentage MOWT in patients who underwent revision hip arthroscopy and to identify predictors of achieving the MOWT. Study Design: Case-control study; Level of evidence, 3. Methods: An anchor question was provided to patients who underwent revision hip arthroscopy between April 2008 and June 2020 who returned for follow-up between August 2019 and June 2021 at one institution. Patients were included if they underwent revision hip arthroscopy, had answered the anchor question, and had baseline and postoperative minimum 1-year follow-up scores for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and the visual analog scale (VAS) for pain. Exclusion criteria were Tönnis grade >1, hip dysplasia, previous hip conditions, or unwillingness to participate. Receiver operating characteristic analysis was used to determine the MOWT. Multivariate logistic regression was used to determine intraoperative predictors of achieving the MOWT. Results: In total, 153 patients (163 hips) were included, with 117 female hips (71.8%), a mean patient age of 34.3 ± 12.4 years, and an average follow-up time of 61.6 ± 42.7 months. It was determined that 77.3% of the patients reported that they would choose to undergo the revision hip arthroscopy again. The MOWT for the mHHS, NAHS, and VAS was 43.1%, 53%, and 33.4%, respectively. The probability of choosing to undergo revision surgery if the MOWT was achieved was 77.5%, 77.6%, and 79.2%, for the mHHS, NAHS, and VAS, respectively. Patients with residual cam-type morphology, which was addressed during the revision, were 2.3 times more likely to achieve the MOWT for the VAS (P = .014). Conclusion: Patients who improved 43.1%, 53%, and 33.4% of their MOWT for the mHHS, NAHS, and VAS, respectively, were likely to be willing to undergo revision hip arthroscopy again. Moreover, the presence of residual cam-type femoroacetabular impingement morphology before their revision surgery was identified as a predictor to achieve the MOWT for the VAS.

Hip–Spine Syndrome in the Nonarthritic Patient

Hip–spine syndrome refers to concurrent hip and spine pathology with overlapping symptoms. Most of the literature has studied it in relation to total hip arthroplasty literature and has been shown to increase dislocation risk. Lumbar spine and pelvic mobility have been studied less frequently in relation to nonarthritic pathologic hip states. Understanding the biomechanical relationship between the lumbar spine, pelvis, and hip can help elucidate how hip–spine syndrome affects the nonarthritic hip and how it impacts outcomes of hip arthroscopy. Changes in lumbar spine motion may be the reason certain predisposed patients develop symptomatic femoroacetabular impingement (FAI) or ischiofemoral impingement. Some athletes may be “hip users” with a low pelvic incidence, making them more reliant on hip motion due to less-intrinsic lumbopelvic motion. When these patients have FAI morphology, their increased reliance on hip motion makes them prone to experiencing femoroacetabular contact and concurrent symptoms. Other athletes may be “spine users,” with larger pelvic incidence and more baseline lumbopelvic motion, making them less reliant on hip motion and therefore less prone to experiencing hip impingement even with hip FAI morphology. Hip–spine syndrome also appears to have an impact on patient selection, role of nonoperative treatment, and hip arthroscopy surgical outcomes. Identifying patients with concurrent pathology may allow surgeons to recommend targeted physical therapy or counsel patients better on their expectations after surgery.

Incidence of Symptomatic Femoroacetabular Impingement: A 4-Year Study at a National Collegiate Athletic Association Division I Institution.

Background:Femoroacetabular impingement (FAI) is an increasingly recognized cause of hip pain in young athletes. Although there are multiple studies that describe the radiographic prevalence of FAI in athletes, its true incidence within this population is unknown.Purpose:To report on the overall and sport-specific incidence of symptomatic FAI in National Collegiate Athletic Association (NCAA) Division I athletes. Return-to-sport times were reported for patients treated operatively.Study Design:Cohort study; Level of evidence, 3.Methods:A retrospective review was conducted to identify all reported hip injuries within a large, multisport NCAA Division I institution. Hip injuries were stratified into FAI, general pain/dysfunction, musculotendinous, ligament, bursitis, bone stress, contusion, and other. FAI was diagnosed based on history, physical examinations, imaging, and symptomatic relief after a diagnostic injection. Descriptive statistics were used to calculate the overall and sport-specific incidence, and chi-square analysis was performed to identify contingency data.Results:In a 3-year period, a total of 5319 musculoskeletal injuries occurred in 1072 athletes. There were 491 (9.2%) hip injuries that occurred in 288 athletes, of which 40 injuries were FAI. The overall incidence of symptomatic FAI was 3.0% of the total population, 3.7% of all injured athletes, and 13.9% of athletic hip injuries. There were no statistically significant differences in FAI rates among male and female athletes overall or among male and female athletes within similar sports. Of the 19 athletes who were treated nonoperatively, 2 failed to return to play: 1 secondary to multiple musculoskeletal injuries and 1 related to cardiac issues. There were 21 hips in 20 patients that were treated operatively, with 1 athlete failing to return to sport. Return to play occurred at a mean of 202 days (range, 81-360 days) after hip arthroscopic surgery.Conclusion:In this large, multisport NCAA Division I cohort, the overall incidence of symptomatic FAI was 3.0% and represented 13.9% of hip injuries. The successful management of FAI with return to play was achieved by both nonoperative and operative treatment methods. The relatively low incidence of symptomatic FAI, despite reports of a high prevalence of FAI morphology in athletes, serves to emphasize the importance of clinical evaluations in treating patients with FAI.

Acetabular labral tear is associated with high pelvic incidence with or without femoroacetabular impingement morphology

PurposeThe aim of this study was to investigate the association between pelvic sagittal parameters and acetabular labral tears.MethodsThree-hundred and sixty-five patients (449 hips) who underwent magnetic resonance imaging (MRI) or magnetic resonance arthrogram (MRA) for hip pain were enrolled in this study. Pelvic sagittal parameters, including the pelvic incidence, pelvic tilt, and sacral slope, were measured with a standing lumbosacral lateral radiograph. All subjects were divided into two groups according to the presence or absence of radiologic acetabular labral tears and compared. Furthermore, the two groups were divided into subgroups according to whether femoroacetabular impingement (FAI) morphology was present or not and compared.ResultsPelvic incidence was greater in the labral tear group than in the non-labral tear group (52.3° ± 8.2° versus 47.1° ± 6.8°, p < 0.001). After accounting for potentially confounding variables, we found that higher age (odds ratio 1.04, 95% confidence interval [CI] 1.02 to 1.06, p = 0.001), FAI (odds ratio 15.11, 95% CI 7.43 to 30.75, p < 0.001), and high pelvic incidence (odds ratio 1.13, 95% CI 1.09 to 1.17, p < 0.001) were independently associated with acetabular labral tear. When only the patients without FAI (308 hips) were divided into groups with and without acetabular labral tear, we found that higher age (odds ratio 1.03, 95% CI 1.01 to 1.06, p = 0.008) and high pelvic incidence (odds ratio 1.15, 95% CI 1.11 to 1.19, p < 0.001) were independently associated with acetabular labral tear.ConclusionAcetabular labral tear is associated with high pelvic incidence with or without FAI morphology.Level of evidenceIII.

Nonarthritic Hip Pathology Patterns According to Sex, Femoroacetabular Impingement Morphology, and Generalized Ligamentous Laxity

Background: Sex differences are frequently encountered when diagnosing orthopaedic problems. Current literature suggests specific sex differences, such as a higher prevalence of cam-type femoroacetabular impingement syndrome in male patients and features of hip instability in female patients. Purpose: To identify hip pathology patterns according to sex, alpha angle deformity, and generalized ligamentous laxity (GLL) in a nonarthritic patient population that underwent primary hip arthroscopy in the setting of femoroacetabular impingement syndrome and labral tears. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients who underwent primary hip arthroscopy between February 2008 and February 2017 were included and separated into male and female groups for initial analysis. Patients were excluded if they had Tönnis osteoarthritis grade >1, previous ipsilateral hip surgery, or previous hip conditions. The demographics, radiographic findings, intraoperative findings, and surgical procedures were then analyzed and compared. Subanalyses were performed for both groups. A threshold of 1 SD above the mean alpha angle in the male group was used to create 2 subgroups. For female patients, GLL based on a Beighton score ≥4 was used to divide the group. Intraoperative findings were compared for both subanalyses. Results: A total of 2701 hips met all inclusion and exclusion criteria. Of those, 994 hips were in the male group and 1707 in the female group. The mean ± SD age was 36.6 ± 13.8 and 37.1 ± 15.0 years for the male and female groups, respectively(P = .6288). The average body mass index was significantly higher in the male group (P < .0001). GLL was more common in women (38.6%) than men (13.6%) (P < .001). The male group had a higher proportion of acetabular Outerbridge grade 3 (21.8%) and 4 (19.2%) lesions when compared with the female group (9.3% and 6.3%, respectively) (P < .0001). Men in the subgroup with an alpha angle ≥78° reported higher rates of acetabular Outerbridge grade 4 damage than men with an alpha angle <78° (P < .001). Mean lateral center-edge angle was lower in the female subgroup with Beighton score ≥4 vs <4 (23.7°± 4.2° vs 31.3°± 5.8°; P < .0001). Conclusion: In this analysis of a large cohort of patients who underwent hip arthroscopy, 2 patterns of hip pathologies were related to sex. On average, male patients had larger alpha angles and increased acetabular chondral damage when compared with their female counterparts. Furthermore, a larger cam-type anatomy was associated with more severe acetabular chondral damage in men. In the female group, the incidence of features of hip instability such as GLL were significantly higher than in the male group.

Cam Morphology Is Associated With Increased Femoral Version: Findings From a Collection of 1,321 Cadaveric Femurs

To evaluate the relationship between femoral version (FV) and α angle (AA) in a large osteological collection of human femurs. The University of Iowa-Stanford osteological collection was used to evaluate the research aims. To measure FV and AA, axial photographs of the proximal femurs were taken, referenced from the posterior condylar axis. FV and AA measurements were obtained using ImageJ software, and the relationship between FV and AA was assessed with repeated-measures analysis of variance and generalized linear models. A P value of <.05 was considered statistically significant. A total of 1321 cadaveric femurs (666 left and 655 right) in 721 cadavers were examined. The average AA for all femurs was 47.8° ± 10.9°, and the average FV for all femurs was 8.53° ± 8.09°. Overall, 191 femurs (14.5%) exhibited cam morphology (AA ≥ 60°). Of the 721 cadavers, 600 had both femurs available for side-to-side comparison. The average FV of femurs with cam morphology was significantly higher than that of femurs without cam morphology (11.70° ± 8.82° vs. 7.99° ± 8.82°, P < .001). Linear regression analysis demonstrated that increased AA was significantly correlated with increased FV (β ± standard error of the mean= 0.21 ± 0.02, P < .0001). In a large osteological collection of human femurs, a significant positive relationship between AA and increasing FV was identified. FAI and hip impingement morphology are more complex than cam or pincer morphology. Cam morphology with high femoral anteversion may allow for normal or near-normal hip mechanics without impingement, and this may partially explain the high rates of asymptomatic cam-type femoroacetabular impingement (FAI) morphology in active and general populations. Given the multiple morphological factors implicated in the development of FAI syndrome, these findings warrant further investigation.

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.

Ossification of the acetabular rim: a highly prevalent finding in asymptomatic non-osteoarthritic hips of all ages

ObjectiveTo estimate the prevalence of acetabular rim ossifications in the adult population with asymptomatic, morphologically normal hips at CT and to determine whether the presence of these ossifications is associated with patient- or hip-related parameters.MethodsWe prospectively included all patients undergoing thoracoabdominal CT over a 3-month period. After exclusion of patients with a clinical history of hip pathology and/or with signs of osteoarthritis on CT, we included a total of 150 hips from 75 patients. We analyzed the presence and the size of ossifications around the acetabular rim. The relationships between the size of acetabular rim ossifications and patient-related (sex, age, BMI) or hip-related parameters (joint space width, and cam- and pincer-type femoroacetabular impingement morphology) were tested using multiple regression analysis.ResultsThe prevalence of acetabular rim ossifications in this population of asymptomatic, non-osteoarthritic hips was 96% (95% CI = [80.1; 100.0]). The presence of ossifications and their size were correlated between the right and left hips (Spearman coefficient = 0.64 (95% CI = [0.46;0.79]), p < 0.05)). The size of acetabular rim ossifications was significantly associated with age (p < 0.0001) but not with BMI (p = 0.35), gender (p = 0.05), joint space width (p ≥ 0.53 for all locations), or any of the qualitative or quantitative parameters associated with femoroacetabular morphology (p ≥ 0.34).ConclusionAcetabular rim ossifications are highly prevalent in asymptomatic, non-osteoarthritic adult hips at all ages. Their size is not correlated with any patient- or hip-related parameters except for age. These findings suggest that ossifications at the acetabular rim, when present in isolation, should not be considered a sign of osteoarthritis or femoroacetabular impingement morphology.Key Points• Acetabular rim ossifications are extremely common in asymptomatic, non-osteoarthritic adult hips.• Acetabular rim ossifications are present independently from other signs of osteoarthritis in adult hips at all ages and should not be interpreted as a pathological finding.• The diagnosis of osteoarthritis or femoroacetabular impingement morphology should not be made based on the sole presence of ossifications at the acetabular rim.

Increased prevalence of femoroacetabular impingement on the elderly with fractures of the proximal femur

Objectives: Femoroacetabular impingement (FAI) has been recently related to several pathologies, besides chondral injury and hip arthritis. We aim to investigate the prevalence of FAI morphology in an elderly cohort hospitalized due to a proximal femur fracture and compare these findings to a control group. We hypothesize that limited medial rotation due to FAI’s morphology could increase stresses to the proximal femur, acting as a facilitating mechanism for fractures in this region. Therefore, a higher prevalence of FAI morphology would be present in the study group. Methods: A retrospective cross-sectional study was performed based on the analysis of radiographic images in AP and lateral views of the fractured hip. Firstly, we have set to measure FAI prevalence in an elderly cohort victimized by fractures of the proximal by measures of the alpha, Tönnis, and lateral center edge angles of a hundred consecutive patients hospitalized for proximal femur fractures. Secondly, we have analyzed the possible relationship between the FAI subtypes and the type of fracture. Finally, we have compared this sample’s data with that of a similar control cohort not affected by fracture. Results: The cohort in this study displayed a higher prevalence of pathological changes in the Tönnis, center-edge, and alpha angles with odds ratios of 3.41, 2.56, and 4.80, respectively (with statistical significance). There was also a significant relationship between cam-type FAI and intertrochanteric fractures, corroborating our initial hypotheses. Conclusions: This study demonstrated that a cohort of older patients affected by fractures of the proximal femur had an increased prevalence of radiographic signs of femoroacetabular impingement. Furthermore, this is the first study demonstrating a statistically significant relationship of cam-type FAI with intertrochanteric fractures, suggesting a possible cause and effect relationship.

Intraarticular Inflammation and Catabolic Markers in Femoroacetabular Impingement during Progression of Disease -comparison between early and late stage disease-

Objectives:Femoroacetabular impingement (FAI) has been proposed as an etiologic factor in up to 50% of osteoarthritis hips (OA). Inflammation is thought to be one of the main initiators of hip OA, yet little is known about the location and progression of intraarticular inflammation in FAI hips. The aim of this study is to characterize inflammation and catabolic markers in the early and late stage of FAI hips in patients with symptomatic Cam FAI.Methods:Head-neck cartilage, acetabular cartilage, and synovial samples were obtained from 30 patients undergoing hip surgery. Fifteen patients had a diagnosis of symptomatic Cam FAI (early FAI-symptomatic FAI) and 15 presented with advanced OA secondary to Cam FAI (late FAI/secondary OA). Control cartilage samples were procured from the head-neck junction of 7 osteochondral fresh allografts from healthy young-adult donors (control). Radiographically, the α-angle was utilized to confirm hip impingement and Tönnis grade was used to define pre-OA (Tönnis grade 0-1) and advanced OA (Tönnis grade >2). Safranin O stained sections were used to assess cartilage degeneration using the Mankin score. Immunostaining of IL-1β, MMP-13, ADAMTS-4, type II collagen (COL2), and the NITEGE aggrecan neoepitote was performed to evaluate inflammation and catabolic markers. Quantification of immunopositive cells was performed and one-way analysis of variance with Tukey’s post hoc test was applied to analyze differences between groups.Results:Characteristics of the study participants are presented in Table 1. Cartilage from the impingement zone (head-neck and acetabulum) of hips with early and late FAI showed microscopic osteoarthritic degenerative changes. Compared to control, head-neck cartilage from early and late stage FAI hips highly expressed inflammatory and catabolic markers IL-1β (69.7±18.1, 72.5±13.2 vs 20.2±4.9), MMP-13 (79.6±12.6, 71.4±18.8 vs 25.3±9.5), ADAMTS-4 (83.9±12.2, 82.6±12.5 vs 24.3±11.1), NITEGE (89.7±7.7, 95.7±4.7 vs 39.8±20.5) (p<0.05). Expression for COL2 was similar among groups (93.6±3.9, 92.5±5.8 vs 95.4±6.4, p=0.4892). Finally, percent of immunopositive cells for IL-1β, MMP-13, ADAMTS-4, and ACAN were positively correlated with Mankin score (r=0.52-0.75; p<0.001). The percentage of immunopositive cells present in acetabular cartilage was similar in both early and late FAI (IL-1β: 83.3 ± 24.8, 80.7 ± 15.6, 80.9 ± 26.3, p = 0.9571; MMP-13: 94.3 ± 9.7, 85.2 ± 12.3, 93.3 ± 10.3, p = 0.0653; ADAMTS-4: 98.5 ± 2.3, 98.4 ± 3.4, 99.2 ± 3.0, p = 0.6997, COL2: 99.8 ± 0.7, 99.7 ± 1.1, 98.6 ± 3.6, p = 0.3830). Additionally, inflammatory and catabolic markers were secreted to the ECM (extracellular matrix) in late FAI but not in early FAI. (Figure 1) Synovitis was minimal in early FAI but severe in late FAI. The average synovitis score was lower in early FAI than late FAI (2.5 ± 1.7, 4.4 ± 1.6; p=0.0086). Lower IL-1β expression levels were noted in synovium from early FAI compared to late FAI (p=0.001).Conclusion:Osteoarthritic degenerative changes, inflammation and catabolic markers are evident in the cartilage from the head-neck and acetabulum (impingement zone) in patients with hip FAI morphology during early and late stage disease. In late disease, increase expression of these markers are also observed in the ECM. Severe synovitis, however, was only evident in late stage disease. This study defines joint specific location and timing of inflammation relative to the disease process, suggesting the impingement area is a potential mediator of inflammation and joint degeneration during disease progression.

FAI morphology increases the risk for osteoarthritis in young people with a minimum follow-up of 25years.

The mechanical conflict in symptomatic femoroacetabular impingement can lead to early osteoarthritis. However, radiographic impingement morphology is often seen in asymptomatic individuals. Long-term observation regarding the risk of developing osteoarthritis in these individuals is lacking. Our study addressed the following questions: Does femoroacetabular impingement morphology increase the risk for development of osteoarthritis after at least 25years? If yes, which radiographic parameter is the most predictive? Does the level of activity influence the risk for development of osteoarthritis? Are PROM influenced by the grade of osteoarthritis in this population? We investigated 51 (32 male, 19 female) patients for whom AP pelvis and Dunn view radiographs were available with a minimum follow-up of 25years. Alpha angle in AP pelvis and Dunn view radiographs, femoral torsion in Dunn view, lateral center edge angle, cross-over sign, posterior wall sign and prominence of ischial spine sign in AP pelvis radiographs were determined. On the follow-up radiographs, osteoarthritis was graded. Tegner Score for the time of the index radiograph was evaluated. Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index were assessed at latest follow-up. The mean follow-up was 43years (range 25-58). Cam impingement morphology showed to increase the risk for development of osteoarthritis: Alpha angles of ≥ 55° on AP pelvis and Dunn view radiographs were associated risk factors and showed an OR of 1.05 (p = 0.002) and 1.10 (p = 0.001), respectively. Abnormal femoral torsion and acetabular retroversion were not risk factors for osteoarthritis. Tegner Score at index presentation, HHS and WOMAC Score did not correlate with the grade of osteoarthritis. This study showed that cam impingement morphology in young patients raises the risk for development of hip osteoarthritis by 5-10% in a long-term follow-up with a minimum of 25years, thus its contribution was small.

A Unique and Characteristic Cam FAI Morphology in Young Patients with Comorbid Inflammatory Conditions.

The relationship between femoroacetabular impingement (FAI) and inflammatory medical comorbidities has not been established in the pediatric population. The purpose of this study was to investigate the prevalence of inflammatory conditions in pediatric patients with FAI and the morphology of the associated deformity. We performed a retrospective cohort study of 90 patients who were diagnosed with FAI in our institution's adolescent hip clinic from January 2016 to March 2018. Patients with an inflammatory comorbidity were identified. Standard quantitative radiographic FAI measurements as well as qualitative femoral head-neck junction morphology were analyzed. Eight patients (8.9%) with 11 symptomatic hips were found to have an inflammatory condition. These 8 patients all had cam deformities. Nine of the symptomatic hips in this subset of patients had a negative femoral offset, where the cam deformity extended beyond the anterior margin of the femoral head. Qualitative assessment revealed a unique head-neck morphology with a prominent and "sharp-edged" bump at the head-neck junction, which resembled an inflammatory beak. In comparing patients with and without inflammatory comorbidities, a marked difference was found for alpha angles (difference, 26.6°; 95% confidence interval [CI], 18.2° to 35.0°) but not for age at diagnosis (difference, 0.5 years; 95% CI, -0.8 to 1.6 years) or the lateral center-edge angle (difference, 1.9°; 95% CI, -3.9° to 7.7°). At our institution, 8.9% of pediatric patients with FAI were found to have an inflammatory comorbidity. These patients presented with a characteristic prominent "sharp-edged" head-neck morphology that standard radiographic measurements captured as a negative femoral offset and a larger alpha angle than was seen in patients without systemic inflammatory disease. Awareness of the characteristic cam deformity that was found in these patients may help to identify patients with undiagnosed inflammatory conditions. This unique deformity also raises questions regarding the possible role of physeal inflammation in the development of cam deformities and indicates a need for additional studies to investigate the relationship between systemic inflammatory diseases and FAI. Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Correlation between the presence of herniation pit and femoroacetabular impingement: a systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis was to evaluate the correlation between the incidence of herniation pits (HPs) and femoroacetabular impingement (FAI)-related morphologies. A systematic search of the MEDLINE, EMBASE, and Cochrane Library databases was performed for studies evaluating the relationship between the incidence of HPs and FAI-related morphologies published up to August 16, 2019. Subgroup analyses were also performed to determine the differences in the relationship between the presence/absence of hip symptoms and cam-/pincer-type FAI. Seven studies involving 7950 hips were included. The pooled odds ratio (OR) for the incidence of HPs in the presence of an FAI-related morphology was 1.64 (95% confidence interval [CI] = 1.09-2.46; P = 0.02). In the subgroup analyses, the ORs for the incidence of HPs in the symptomatic and asymptomatic hips were 1.00 (95% CI 0.40-2.51; P = 1.00) and 1.59 (95% CI 1.42-1.77; P < 0.0001), respectively; the ORs for the incidence of HPs in the cam- and pincer-type FAI were 1.61 (95% CI 1.43-1.81; P < 0.0001) and 1.42 (95% CI 0.77-2.61; P = n.s.), respectively. The incidence of HPs has a significant relationship with FAI-related morphology, especially in asymptomatic patients and those with cam-type FAI morphology. III.

Predictors of Outcomes After Hip Arthroscopic Surgery for Femoroacetabular Impingement: A Systematic Review.

Background:The benefits of hip arthroscopic surgery in the setting of femoroacetabular impingement (FAI) have been well established; however, some patients may experience a greater degree of improvement than others. Identifying positive and negative predictors of outcomes would assist the orthopaedic surgeon’s management algorithm for patients with FAI.Purpose/Hypothesis:The objective of this systematic review was to identify demographic, radiographic, and other operative predictors of positive and negative outcomes after hip arthroscopic surgery for patients with FAI. It was hypothesized that factors including FAI morphology, age, body mass index (BMI), sex, dysplasia, articular cartilage damage, radiographic joint space, and labral treatment would predict outcomes after hip arthroscopic surgery.Study Design:Systematic review; Level of evidence, 4.Methods:This systematic review was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Three databases (Embase, PubMed, and Ovid [MEDLINE]) were searched on May 19, 2018, using terms including “hip,” “arthroscopy,” and “FAI.” Studies were screened and data extracted in duplicate.Results:A total of 39 studies were included in this systematic review, comprising 9272 hips with a mean age of 36.5 years (47.2% female). Younger age, male sex, lower BMI (<24.5 kg/m2), Tönnis grade 0, and preoperative pain relief from diagnostic intra-articular hip injections predicted positive outcomes. Female sex, older age (>45 years), longer duration of preoperative symptoms (>8 months), elevated BMI, increased Tönnis grade (≥1), chondral defects, decreased joint space (≤2 mm), increased Kellgren-Lawrence grade (>3), increased lateral center-edge angle (LCEA), and undergoing labral debridement alone were predictors of negative outcomes.Conclusion:In patients with FAI, younger age, male sex, lower BMI (<24.5 kg/m2), Tönnis grade 0, and pain relief from preoperative intra-articular hip injections are significantly more likely to achieve positive outcomes after hip arthroscopic surgery. On the other hand, older age (>45 years), female sex, elevated BMI, osteoarthritic changes, decreased joint space (≤2 mm), chondral defects, increased LCEA, and undergoing labral debridement compared with labral repair are associated with negative outcomes.