Diagnosis Of Femoroacetabular Impingement Research Articles

Labral Ossification and Sacroiliac Joint Disease: Could There Be a Link to an Autoimmune Etiology?

To determine the prevalence of ipsilateral sacroiliac (SI) joint disease among patients with symptomatic femoroacetabular impingement (FAI) associated with labral ossification (LO) who underwent hip arthroscopy compared with a matched control group of patients with symptomatic FAI and no LO. Computed tomography (CT) scans of all patients undergoing arthroscopic correction of FAI were obtained. The inclusion criterion for the study group was a diagnosis of FAI with a secondary diagnosis of LO made by plain radiography, CT, or magnetic resonance imaging or made intraoperatively. The exclusion criterion was the absence of evidence of LO. We reviewed 52 patients (56 hips) with LO to assess the SI joint and compared them with a control group matched by age, sex, and FAI type. The SI joints were graded according to the modified New York criteria. CT scans were available for evaluation of the ipsilateral SI joint in 28 patients (29 hips) with LO: 17 women and 11 men with an average age of 44.6years (range, 26-56years). Of the hips, 23 had combined FAI and 6 had pincer-type FAI. The control group consisted of 29 hips, exactly matched for sex and FAI type, with an average age of 44.8years (range, 21-58years). Grade 3 SI joint abnormalities were significantly more prevalent in the LO group (28%) than in the control group (7%, P= .037), and grade 0 or 1 changes (relatively normal SI joints) were significantly less common in patients with LO (38%) than in controls (72%, P= .008). Subanalysis showed that 35% of the LO group aged 45years or younger had ipsilateral grade 3 SI joint abnormalities compared with none of the control patients aged 45years or younger (P= .041). Grade 3 changes were found in 42% of male patients with LO compared with 8% of male controls (P= .155). Grade 3 changes were noted in 18% of women in the LO group compared with 6% of female controls (P= .601). Patients with symptomatic FAI and LO are more likely to show associated SI joint pathology than patients with FAI not involving LO. These differences are greatest among men and among patients aged 45years or younger. Level III, retrospective case-control study.

Bilateral Femoroacetabular Impingement: What is the Fate of the Asymptomatic Hip?

Bilateral symptomatic femoroacetabular impingement (FAI) is common. However, the fate of asymptomatic hip in patients with the radiographic diagnosis of bilateral FAI and unilateral symptoms remains unknown. (1) What is the likelihood of the asymptomatic hip becoming painful in patients with unilateral symptoms but with radiographic evidence of bilateral femoroacetabular impingement? (2) What radiological and clinical factors are associated with the development of symptoms in an asymptomatic hip diagnosed with FAI? A longitudinally maintained institutional FAI database was queried to collect relevant data for this retrospective study. To answer our research questions, we created a cohort of patients with bilateral radiographic signs of FAI but only unilateral symptoms at the time of initial presentation. Between 2004 and 2016, a senior surgeon (JP) at one institution treated 652 patients for hip pain determined to be from FAI, a diagnosis we made based on clinical symptoms, physical exam, and diagnostic imaging. We excluded 95 patients (15%) because of inadequate data or other diagnoses, which left 557 patients. Of those, 170 patients (31%) had bilateral radiological diagnosis of FAI, and 88 (52%) of them had bilateral hip symptoms, and so were excluded. Of the remaining 82 patients, eight (10%) underwent bilateral FAI surgery under the same anesthetic despite having only unilateral symptoms, leaving 74 for analysis in this study. Patients were followed with annual clinic visits, or contacted by phone and electronically. We defined onset of symptoms using a modified Harris Hip Score (mHHS) or the University of California at Los Angeles (UCLA) activity scale, and used a logistic regression model to identify factors associated with the development of symptoms. Of the 74 patients with bilateral FAI and an asymptomatic hip at initial presentation, 60 (81%) became symptomatic at a mean 2 years (range, 0.3-11 years) followup. Of these 60 patients, 43 (72%) eventually underwent subsequent surgical intervention. After controlling for potential confounding variables such as sex, age, BMI, history of trauma we identified that reduced neck-shaft angle (r = -0.243, p = 0.009), increased lateral center-edge angle (r = 0.123, p = 0.049), increased alpha angle (r = 0.069, p = 0.025), and younger age (r = -0.071, p = 0.046) were associated with the development of symptoms in the contralateral hip. With the numbers available, none of the other examined variables such as sex, BMI, history of trauma, psychiatric condition, employment, Tönnis grade, Tönnis angle, crossover sign, type of impingement, and joint congruency were found to be associated with symptom progression. Bilateral FAI may be observed about one-third of patients. Most patients with unilateral symptomatic FAI and radiographic diagnosis of bilateral FAI in this cohort became symptomatic relatively quickly and most of them underwent subsequent surgical intervention in the contralateral hip. Reduced neck-shaft angle, increased lateral center-edge angle, increased alpha angle, and younger age were associated with symptom development in the contralateral hip. Hip preservation surgeons may use the finding of this study to counsel patients who present with bilateral FAI but only unilateral symptoms about the natural history of their condition. Level III, therapeutic study.

The Pattern of Acetabular Cartilage Wear Is Hip Morphology-dependent and Patient Demographic-dependent.

The Pattern of Acetabular Cartilage Wear Is Hip Morphology-dependent and Patient Demographic-dependent.

Increased Prevalence of Femoroacetabular Impingement in Patients With Proximal Hamstring Tendon Injuries

To determine the prevalence of clinically diagnosed femoroacetabular impingement (FAI) in a consecutive series of patients presenting with proximal hamstring tendon injury and to correlate this with pelvic anatomic factors. The prevalence of clinically symptomatic cam-, pincer-, and mixed-type and overall FAI was calculated among a consecutive series of patients presenting to a hip preservation clinic with a confirmed clinical and radiographic diagnosis of proximal hamstring tendon injury between 2012 and 2017. The presence of a cam lesion was determined by an alpha angle > 50° on radiographs and computed tomography radial sequences of the head-neck junction and a femoral head-neck offset ratio < 0.18. Clinical diagnoses of osseous impingement were determined according to accepted pathomorphologic signs and measurements. A diagnosis of FAI was confirmed by imaging findings of acetabular overcoverage for pincer-type FAI and the presence of an anterior or lateral cam lesion for cam-type FAI. Overall, 120 hips in 97 patients (mean age, 45years) were included in this study. A clinical diagnosis of FAI was noted in 70.8% of hips (pincer-type 9.2%, cam-type 40.8%, mixed-type 20.8%), an approximate 2- to 7-fold increased prevalence in comparison with the general population from prior studies. The prevalence of FAI is high in patients with symptomatic proximal hamstring tendon pathology. Because FAI results in restriction of hip range of motion and altered pelvic tilt, future studies are warranted to investigate whether the presence of FAI acts as a predisposing factor for injury to the hamstring muscle complex. Level IV, case series.

FEMOROACETABULAR IMPINGEMENT INSURANCE COVERAGE TRENDS IN RECENT YEARS: A COHORT BASED ANALYSIS

Background: The diagnostic criteria for surgical indication of femoroacetabular impingement (FAI) remain controversial. With a growing body of literature investigating the quality of these criteria, little is known about the direction that these have had on changes of third-party policies. The purpose of this study was to measure how these changes in policy would affect the exclusion of a cohort of previously identified FAI patients who were treated operatively. Methods: Four insurance companies’ coverage policies with specific criteria for the surgical treatment of FAI were applied to this population at two time points, 2012 and 2018, to determine whether these third-party payer criteria for FAI surgery were met. The insurance criteria were assessed in a prospective multicenter cohort of 712 patients undergoing primary FAI surgery. The policies listed various combinations of age, symptom duration, positive impingement test, radiographic osteoarthritis, radiographic sign of CAM and/or pincer impingement, and physical exam findings. Results: The cohort of 712 hips included 324 men [45.5%] and 388 females [54.5] with a mean age of 28.7 years. Overall, insurance criteria were not met in: Insurance #1 old 30.1%, new 25.7%; Insurance #2 old and new 17.8%, Insurance #3 old 21.9%, new 21.1%; and Insurance #4 old 17.8%, new 14.9%-20.6%. In 2012, the average percent exclusion of the four companies was 21.9%, this number decreased slightly to 20.6% overall in 2018. The most likely reason to be excluded was found to be failure to meet imaging criteria. The second most likely failed characteristic was a negative impingement test (65 patients excluded). Several insurance companies continue to utilize Outerbridge criteria for cartilage lesions which cannot be assessed preoperatively. Discussion and Conclusion: The diagnosis of FAI and its surgical indications have no definitive set criteria. Our study shows that with a six-year span of growing literature and updated policies, nearly 1 in 5 patients deemed to need surgical intervention by experienced hip preservation surgeons would still be denied coverage. There is a need for continued improvement of consensus regarding the diagnosis of FAI and appropriate indications for surgical intervention based on the available literature.

BORDERLINE ACETABULAR DYSPLASIA: INDEPENDENT PREDICTORS OF HIP INSTABILITY VERSUS IMPINGEMENT

Background: Hips with borderline acetabular dysplasia (lateral center-edge angle, LCEA, between 20° and 25°) are challenging in terms of diagnostic and treatment decision-making. It is accepted that a portion of this population has primarily hip instability-based symptoms consistent with symptomatic acetabular dysplasia, while others have primarily hip impingement-based symptoms consistent with femoroacetabular impingement (FAI). Nevertheless, the diagnostic characteristics that differentiate hip instability and FAI have not been identified. The purpose of this study was to examine a cohort of patients with minor acetabular dysplasia features in order to identify the preoperative clinical characteristics and imaging findings that differentiate patients with hip instability from patients with FAI. Methods: A retrospective cohort study of patients with borderline acetabular dysplasia was performed. Utilizing our institution’s hip preservation database, we identified 143 consecutive hips in 134 patients undergoing hip preservation surgery in the setting of borderline acetabular dysplasia. All patients were identified by prospective radiographic evaluation with an LCEA between 20° and 25°. Inclusion criteria included age 14-40 years and primary surgical treatment. Medical records were reviewed to determine patient demographics, details of clinical presentation, baseline patient-reported outcome scores, physical exam findings, plain radiographic findings, and the operative procedures performed. Statistical analyses were used to compare the clinical features and imaging parameters of the symptomatic acetabular dysplasia and FAI subgroups. Results: Of the 143 hips in the cohort, 39.2% (n = 56) had the diagnosis of symptomatic instability, while 60.8% (n = 87) had the diagnosis of FAI. The cohort included 109 females (76.2%) and 34 males (23.8%). Hips with instability (compared to FAI) had a significantly lower LCEA (21.8° vs. 22.8°; p &lt; 0.001), lower ACEA (23.3° vs. 26.6°; p = 0.002), a higher AI (11.8° vs. 8.5°; p &lt; 0.001), and a lower maximum alpha angle (54.4° vs. 61.1°; p = 0.001). The odds of instability increased 1.7 times for each one-degree decrease in LCEA, 1.4 times for each one-degree decrease in ACEA, and 1.1 times for each one-degree increase in acetabular inclination (all p &lt; 0.003). Sex was strongly associated with the clinical diagnosis, with instability present in 48.6% of females compared to only 8.8% of males (p &lt; 0.001). Patients with instability presented with significantly greater disability, as indicated by the modified Harris hip score, UCLA activity, SF-12 physical function, and HOOS (pain, activities of daily living, sports and recreation, and quality of life) scores (all p = 0.05). The symptomatic acetabular dysplasia subgroup had significantly greater range of motion in terms of internal rotation in flexion (IRF, 22.7° vs. 12.4°, p &lt; 0.001) and total arc of rotational motion (IRF+ERF, 61.2° vs. 47.4°, p &lt; 0.001). Lateral hip pain was present in 42.9% (24/56) of hips in the instability group compared to 25.3% (22/87) of hips in the impingement group (p = 0.03). Conclusions: We found significant differences in the clinical characteristics and radiographic features of the symptomatic acetabular dysplasia and FAI subgroups within the borderline dysplasia cohort. Patients with symptomatic instability tend to have lateral hip pain, greater functional limitations, higher range of motion, and a greater AI, while patients with impingement symptoms tend to have more limited range of motion (especially IRF), a greater ACEA, and a greater alpha angle.

ACC Research Agenda Conference 2019: Peer Reviewer Acknowledgments and Abstracts of Proceedings.

ACC Research Agenda Conference 2019: Peer Reviewer Acknowledgments and Abstracts of Proceedings.

Femoroacetabular impingement - Update 2019

Since the first description of the femoroacetabular impingement (FAI) concept diagnostic imaging of FAI has continuously been developed. The biomechanical concept is explained and an update on diagnostic imaging of FAI is presented. Based on a literature search this review article presents the current state of knowledge about FAI mechanisms and gives an overview on state of the art radiological diagnostics. A perspective on new imaging methods is also given. The FAI is adynamic phenomenon with amechanical conflict between the femoral head and/or neck and the acetabulum. It is usually suspected clinically; however, imaging plays an essential role in establishing the diagnosis by detecting and defining the underlying deformities of the proximal femur (cam deformity) and the acetabulum (pincer deformity) and by evaluating associated lesions of the articular cartilage and labrum. Basic imaging diagnostics consist of anteroposterior and lateral radiographs. Magnetic resonance imaging (MRI) and MR arthrography are the preferred imaging modalities for detailed analysis of deformities, for the detection and graduation of lesions of articular cartilage (sensitivity 58-91%) and labral lesions (sensitivity 50-92%). Simultaneously, these methods can exclude other hip diseases. Current standards and new developments in FAI imaging are presented. For the diagnosis of FAI typical clinical and imaging findings are required. Radiological diagnostics are an indispensable component in establishing the diagnosis of FAI, in the differentiation of the underlying deformities and in the assessment of treatment-relevant joint damage.

Frequency of Subspine Impingement in Patients With Femoroacetabular Impingement Evaluated With a 3-Dimensional Dynamic Study

(1) To estimate the frequency of subspine impingement (SSI) morphology in patients with a diagnosis of femoroacetabular impingement (FAI) and (2) to describe the performance of the alpha angle, range of motion, and femoral and acetabular anteversion for the identification of cases with and without SSI morphology. We performed a retrospective observational study of patients with symptomatic FAI evaluated by computed tomography between February 2015 and June 2017. SSI morphology was identified using a 3-dimensional dynamic study with Move Forward software. A case was considered positive if a contact area of the anterior inferior iliac spine with the femoral neck was evidenced. Measurements of acetabular anteversion, femoral anteversion, the lateral center-edge angle, the alpha angle, and the neck-shaft angle, as well as range-of-mobility data, were collected. The study included 135 patients (194 hips), with a mean age of 39.1 ± 13.9years; 65.2% were women. SSI morphology was found in 23.7% of hips (46 hips) (95% confidence interval, 18.3%-30.2%). Of the hips identified with SSI, 52.2% had a type I anterior inferior iliac spine, 41.3% had type II, and 6.5% had type III. In hips with SSI, median femoral anteversion was 5.6° (interquartile range, 2.1°-7.5°) and values of less than 8° would increase the suspected SSI morphology (81.8% sensitivity, 70.5% specificity). SSI morphology is a frequent finding in patients with symptomatic FAI through a 3-dimensional dynamic study. A decrease in femoral anteversion could be considered a useful criterion to suspect SSI morphology. Level IV, case series.

Biomarkers for Femoroacetabular Impingement and Hip Osteoarthritis: A Systematic Review and Meta-analysis

Background: The early recognition and management of patients with hip lesions, such as femoroacetabular impingement (FAI) and early hip osteoarthritis (OA), may preempt significant hip morbidity. The identification of reliable biomarkers may help guide decision making in an efficient and cost-effective manner. Purpose: To determine the biomarkers that have been associated with FAI as well as identify serum, synovial, and urinary analytes that have shown clinical utility in the prediction or identification of hip OA. Study Design: Systematic review and meta-analysis. Methods: The terms “hip arthroscopy,” “femoroacetabular impingement,” “labral tear,” “osteoarthritis,” and “biomarker” were searched in PubMed, Web of Science, Scopus, Cochrane Library, and Google Scholar, yielding 276 articles. After screening, 7 articles were included. Pooled estimates were calculated utilizing a fixed-effects inverse-variance model weighted for individual study size. Results: A total of 1747 patients with a mean age of 37.5 ± 4.5 years (76.4% female) were identified. Forty-three unique biomarkers were assessed. Although general proinflammatory cytokines IL-1 and TNF-α exhibited inconsistent trends in arthritic hips, IL-6 demonstrated a consistent increase (+84.8% [95% CI, 81.9%-87.6%]; P < .05). A significant difference was found in levels of the fibronectin-aggrecan complex (FAC) in patients with OA compared with controls (0.08 ± 0.40 vs 1.15 ± 0.35 μg/mL, respectively; P < .001). It was the only specific analyte to show a significant difference between those with and without OA. In the setting of FAI, cartilage oligomeric matrix protein (COMP) was significantly increased in athletes after adjusting for concurrent knee and hip OA. A statistically significant difference was present in FAI-positive hips (9.0 ± 0.1 [95% CI, 8.8-9.3]) compared with controls (8.4 ± 0.1 [95% CI, 8.2-8.4]) (P < .05). Other biomarkers, such as CXCL3, which exhibited statistically significant differences compared with controls, did not control for underlying factors such as age and concomitant lesions. Conclusion: COMP and FAC are specific biomarkers with potential utility in the diagnosis and management of FAI and hip OA, given their ability to differentiate between controls and patients with hip lesions. Further research is necessary to identify their ability in determining disease severity, predicting the response to treatment, and establishing an association with the risk of long-term OA.

Pincer‐type MRI morphology seen in over a third of asymptomatic healthy volunteers without femoroacetabular impingement

In daily routine, pincer femoroacetabular impingement (FAI) findings are often seen without a clinical diagnosis of pincer FAI. To assess the presence of pincer FAI MRI findings in asymptomatic volunteers with negative impingement test versus patients with clinically confirmed FAI. Case-control study. Sixty-three asymptomatic volunteers and 63 matched patients with FAI were included. A coronal T1 -weighted turbo spin-echo sequence as well as a 3D oblique transverse water-excitation true fast imaging sequence at 1.5T. The volunteers underwent standard MRI of the hip, and patients underwent MR arthrography of the symptomatic hip using the same MR sequences. Measurements of cranial acetabular version, acetabular depth, and lateral center-edge angle were performed independently by three fellowship-trained musculoskeletal radiologists. Descriptive statistics, Mann-Whitney U-test, Unpaired t-test, receiver operating characteristics (ROC), Intraclass correlation coefficient (ICC). Forty-one percent (26/63, reader 1), 32% and 37% (20 and 23/63, reader 2/3) of asymptomatic volunteers had at least one positive MR finding for pincer-FAI. Patients with pincer or mixed-type FAI had cranial retroversion of the acetabulum of -0.2° ± 7.1 (mean ± standard deviation) for reader 1 and -0.3° ± 5.5/-0.2° ± 4.8 for reader 2 / reader 3, while asymptomatic volunteers had an anteversion of 6.2° ± 6.4 (reader 1) and 3.2° ± 4.9/3.1° ± 6.5 (readers 2/3): This difference was statistically significant (P ≤ 0.002), but there was a large overlap between the groups. Acetabular depth measurements were very similar for patients with either pincer or mixed-type FAI (5.1-5.3 mm ± 3.1) and volunteers (5.2-6.1 mm ± 2.6), without a statistically significant difference (P ≤ 0.50). Lateral center-edge angle was also similar in patients with either pincer or mixed-type FAI (32.1-35.1° ± 9.1) and volunteers (30.7-33.2° ± 6.5), without a statistically significant difference (P ≤ 0.28). There is a large overlap in pincer-type MRI findings between patients with symptomatic FAI and asymptomatic volunteers. More than a third of volunteers exhibited at least one positive pincer-type MRI finding. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1296-1303.

Os acetabuli and femoro-acetabular impingement: aetiology, incidence, treatment, and results.

The purpose of this study was to investigate the pathogenesis, the incidence, and the results of arthroscopic treatment of os acetabuli (OSA) in a group of patients with diagnosis of femoro-acetabular impingement (FAI). We retrospectively analyzed the full documentation of 294 hips in 273 patients (21 bilateral) operated for FAI through hip arthroscopy. We reviewed all radiographs and arthro-MRI in order to identify the incidence of OSA. All patients with OSA were then assessed with a modified Harris hip score (MHHS) pre-operatively and at the final follow-up. Twenty-one patients (7.7%), 20 (95%) of them were male, were diagnosed with concomitant FAI and os acetabuli. In 21 cases, OSA was excised and FAI was treated with rim trimming, femoral osteoplasty, or both. In one case, a large OSA fragment was fixed with a 4mm screw avoiding an acetabular uncoverage if excised. The average follow-up was 31months (range from 6 to 69months). The MHHS showed an improvement from a pre-operative MHHS of 57.5 (range from 39 to 82) to 95 (range from 73 to 100). Os acetabuli is not uncommon and certainly associated with FAI and male gender. The etiology is probably microtraumatic. The arthroscopic OSA removal or fixation and concomitant FAI treatment showed very good results. Interestingly, these outcomes seem better than FAI treatment alone. Further studies with a wider number of patients and a longer follow-up are needed to confirm these results and understand the real role of OSA in this setting.

Which Two-dimensional Radiographic Measurements of Cam Femoroacetabular Impingement Best Describe the Three-dimensional Shape of the Proximal Femur?

Many two-dimensional (2-D) radiographic views are used to help diagnose cam femoroacetabular impingement (FAI), but there is little consensus as to which view or combination of views is most effective at visualizing the magnitude and extent of the cam lesion (ie, severity). Previous studies have used a single image from a sequence of CT or MR images to serve as a reference standard with which to evaluate the ability of 2-D radiographic views and associated measurements to describe the severity of the cam lesion. However, single images from CT or MRI data may fail to capture the apex of the cam lesion. Thus, it may be more appropriate to use measurements of three-dimensional (3-D) surface reconstructions from CT or MRI data to serve as an anatomic reference standard when evaluating radiographic views and associated measurements used in the diagnosis of cam FAI. The purpose of this study was to use digitally reconstructed radiographs and 3-D statistical shape modeling to (1) determine the correlation between 2-D radiographic measurements of cam FAI and 3-D metrics of proximal femoral shape; and 2) identify the combination of radiographic measurements from plain film projections that were most effective at predicting the 3-D shape of the proximal femur. This study leveraged previously acquired CT images of the femur from a convenience sample of 37 patients (34 males; mean age, 27 years, range, 16-47 years; mean body mass index [BMI], 24.6 kg/m, range, 19.0-30.2 kg/m) diagnosed with cam FAI imaged between February 2005 and January 2016. Patients were diagnosed with cam FAI based on a culmination of clinical examinations, history of hip pain, and imaging findings. The control group consisted of 59 morphologically normal control participants (36 males; mean age, 29 years, range, 15-55 years; mean BMI, 24.4 kg/m, range, 16.3-38.6 kg/m) imaged between April 2008 and September 2014. Of these controls, 30 were cadaveric femurs and 29 were living participants. All controls were screened for evidence of femoral deformities using radiographs. In addition, living control participants had no history of hip pain or previous surgery to the hip or lower limbs. CT images were acquired for each participant and the surface of the proximal femur was segmented and reconstructed. Surfaces were input to our statistical shape modeling pipeline, which objectively calculated 3-D shape scores that described the overall shape of the entire proximal femur and of the region of the femur where the cam lesion is typically located. Digital reconstructions for eight plain film views (AP, Meyer lateral, 45° Dunn, modified 45° Dunn, frog-leg lateral, Espié frog-leg, 90° Dunn, and cross-table lateral) were generated from CT data. For each view, measurements of the α angle and head-neck offset were obtained by two researchers (intraobserver correlation coefficients of 0.80-0.94 for the α angle and 0.42-0.80 for the head-neck offset measurements). The relationships between radiographic measurements from each view and the 3-D shape scores (for the entire proximal femur and for the region specific to the cam lesion) were assessed with linear correlation. Additionally, partial least squares regression was used to determine which combination of views and measurements was the most effective at predicting 3-D shape scores. Three-dimensional shape scores were most strongly correlated with α angle on the cross-table view when considering the entire proximal femur (r = -0.568; p < 0.001) and on the Meyer lateral view when considering the region of the cam lesion (r = -0.669; p < 0.001). Partial least squares regression demonstrated that measurements from the Meyer lateral and 90° Dunn radiographs produced the optimized regression model for predicting shape scores for the proximal femur (R = 0.405, root mean squared error of prediction [RMSEP] = 1.549) and the region of the cam lesion (R = 0.525, RMSEP = 1.150). Interestingly, views with larger differences in the α angle and head-neck offset between control and cam FAI groups did not have the strongest correlations with 3-D shape. Considered together, radiographic measurements from the Meyer lateral and 90° Dunn views provided the most effective predictions of 3-D shape of the proximal femur and the region of the cam lesion as determined using shape modeling metrics. Our results suggest that clinicians should consider using the Meyer lateral and 90° Dunn views to evaluate patients in whom cam FAI is suspected. However, the α angle and head-neck offset measurements from these and other plain film views could describe no more than half of the overall variation in the shape of the proximal femur and cam lesion. Thus, caution should be exercised when evaluating femoral head anatomy using the α angle and head-neck offset measurements from plain film radiographs. Given these findings, we believe there is merit in pursuing research that aims to develop the framework necessary to integrate statistical shape modeling into clinical evaluation, because this could aid in the diagnosis of cam FAI.

Does 3DMR provide equivalent information as 3DCT for the pre-operative evaluation of adult Hip pain conditions of femoroacetabular impingement and Hip dysplasia?

Femoroacetabular impingement (FAI) and hip dysplasia (HD) are frequently evaluated by isotropic CT (3DCT) for preoperative planning at the expense of radiation. The aim was to determine if isotropic MRI (3DMR) imaging can provide similar quantitative and qualitative morphological information as 3DCT. 25 consecutive patients with a final diagnosis of FAI or HD were retrospectively selected from December 2016-December 2017. Two readers (R1, R2) performed quantitative angular measurements on 3DCT and 3DMR, blinded to the diagnosis and each other's measurements. 3DMR and 3DCT of the hips were qualitatively and independently evaluated by a radiologist (R3), surgeon (R4), and fellow (R5). Interobserver and intermodality comparisons were performed. The ICC was good to excellent for all measurements between R1 and R2 (ICC:0.60-0.98) and the majority of intermodality measurements for R1 and R2. Average inter-reader and inter-modality PABAK showed good to excellent agreement for qualitative reads. On CT, all alpha angles (AA) were significantly lower in dysplasia patients than in cam patients (p < 0.05). All lateral center-edge angle (LCEA) were significantly lower in dysplasia than in cam patients (p < 0.05). On MR, AA at 12, 1, and 2 o'clock, and LCEA at center were significantly lower in dysplasia patients than in cam patients (p < 0.05). 3DMR offers similar qualitative and quantitative analysis as 3DCT in adult painful hip conditions. 3DMR has good potential to replace 3DCT and serve as a one-stop modality for bone and soft tissue characterizations in the pre-operative evaluation of FAI and HD.

Validation of the Brazilian version of the Hip Outcome Score (HOS) questionnaire

BackgroundThe Hip Outcome Score (HOS) was developed to evaluate physically active patients with hip disease but without severe degenerative change. A translation and cultural adaptation into Brazilian Portuguese was previously conducted. The aim of this study was to validate the Brazilian version of the HOS (HOS-Brazil) among a group of physically active patients with a diagnosis of femoroacetabular impingement (FAI) or greater trochanteric pain syndrome (GTPS).MethodsThe following questionnaires were applied: the HOS-Brazil; the validated Brazilian versions of the Nonarthritic Hip Score (NAHS) and the 12-Item Short-Form Health Survey (SF-12). The psychometric properties analyzed with regard to the validation process were reliability and validity. Internal consistency and intra-rater test-retest reliabilities were analyzed using Cronbach’s alpha and the intraclass correlation coefficient (ICC) statistical tests based on test-retest agreement. Construct and content validities were examined using Pearson’s correlation coefficient. Content validity was also analyzed based on evidence of floor, ceiling, or both types of effects from the questionnaires.ResultsA total of 70 male and female patients were selected, aged between 19 and 70 years old. The internal consistency and intra-rater test-retest reliability values were high (Cronbach’s α > 0.9; ICC > 0.9). The questionnaire showed acceptable convergent (r > 0.7) and divergent (r < 0.4) validities. No floor or ceiling effects were observed.ConclusionThe HOS-Brazil was validated. Additional studies are underway to evaluate its responsiveness.

Hip morphology and patient factors associated with severity of hip symptoms in femoroacetabular impingement

Purpose: Femoroacetabular impingement (FAI) syndrome is a clinical disorder of the hip associated with pain and dysfunction, thought to be a precursor to hip osteoarthritis (OA). Several interacting anatomical parameters have been linked to the pathomechanism of FAI, including the alpha angle (αA), beta angle (βA), lateral centre edge angle (LCEA), acetabular version, femoral version, and femoral neck shaft angle (FNSA). Previous investigations of anatomical parameters and hip symptoms in FAI cohorts have primarily used plain radiographs, which permit only single-planar representation of the complex morphology of the femoral head and acetabulum, limiting analysis to the sub-region profiled. MRI provides multiplanar morphologic assessment without the use of ionizing radiation, with potential for post-processing of volumetric sequences to provide comprehensive, multi-planar consideration of αA, βA, femoral and acetabular version. We sought to study the relationship between symptom severity, morphological parameters and patient-level factors in FAI. Methods: Eighty-nine participants were diagnosed with FAI syndrome in a clinical setting by an orthopaedic surgeon. Age, gender, body mass index, nature of onset (gradual vs sudden) and duration of symptoms were recorded. Participants completed the international Hip Outcome Tool-33 (iHOT-33), a measure of hip health-related quality of life (QOL) (0 = worst possible QOL, 100 = best possible QOL), and the 10-point modified UCLA activity score (1 = “regular participation in impact sports”, 10 = “wholly inactive and dependent on others”). Participants received standardized plain radiographs and hip MRI scans on one of two 3T scanners (Siemens Prisma & Skyra). On a subset of 60 participant scans (41 cam-type, 3 pincer-type, 16 mixed-type FAI), αA was measured in four reconstructed radial planes at 30-degree intervals from superior to anterior (Fig. 1). The βA, defined as the angle formed by the αA vector and a line joining the centre of the femoral head to the acetabular rim, was also measured in these four planes. Femoral version was measured using axial hip and knee MRI sequences. Acetabular version was measured at 1cm inferior to the acetabular sourcil, using axial hip MRI sequences with the bi-ischial line as a reference point. LCEA and FNSA were measured on an AP pelvis X-ray. Statistical analyses included Pearson’s linear regressions and students' t-tests. Results: The 89 participants (32.9 ± 10.7 yrs, 40% female) had a mean iHOT-33 score of 41.0 ± 18.3. Modified UCLA activity scores and iHOT-33 scores were significantly associated (r = −0.351, P = 0.001), suggesting that more activity lends itself to better hip health-related QOL. Higher participant activity levels were also associated with a shorter duration of symptoms (r = 0.361, P = 0.001). No other patient factors were related to iHOT-33 score. The only anatomical parameter significantly associated with iHOT-33 score was the αA in the anterosuperior radial plane (r = −0.297, P = 0.025) (Table 1). Those with larger αAs (>75 degrees, n = 13) had significantly lower iHOT-33 scores than those with smaller αAs ( 75 degrees) and smaller αAs (<75 degrees) in any other radial plane, including for the maximum αA measured for each hip. Conclusions: Alpha angle in the anterosuperior radial plane was associated with hip health-related QOL, whereas other anatomical parameters, including αA measured in other radial planes, were not. Clinically, this finding supports the need for αA measurement at the anterosuperior radial plane in FAI diagnosis, and potentially highlights the importance of bony surgical correction at this region. Previous research has identified the anterosuperior region as particularly susceptible to chondrolabral damage in FAI; our study's findings link this structural damage to the presence of symptoms in FAI.

Treatment of Femoroacetabular Impingement with a Mini-open Direct Anterior Approach

Background:The opinion about best methods of femoroacetabular impingement (FAI) treatment are not consistent. Operative treatment of this condition may be arthroscopic, but open procedures with osteotomy of the greater trochanter and hip dislocation has been used. The present study evaluates the benefits of the mini-open direct anterior approach (DAA) in treating patients with FAI, with is a procedure available for most orthopedic surgeons.Materials and Methods:39 patients treated for FAI (25 men and 14 women) at an average age of 29.3 years (range 18–46 years) were reviewed in this retrospective study. The mean followup was 45 months, (range 24-55 months). The hip impingement test was positive in all patients. The diagnosis of FAI was confirmed on anteroposterior and lateral hip view radiographs. All patients were operated with mini-open DAA. The outcomes were assessed with the Harris Hip Score, Short-Form 36 Health Survey and VAS score. Preoperative osteoarthritis was assessed according to Tönnis score.Results:At the final followup, improvement was noted compared to preoperative status in Harris Hip Score (P < 0.00001), visual analog scale score (P < 0.001), and Short-Form-36 score (P < 0.001). Nineteen patients returned to their previous sports activities. No major complications occurred. One patient developed heterotopic ossification and three patients developed temporary postoperative meralgia paresthetica. Five patients from the treatment group required total hip arthroplasty for severe osteoarthritis.Conclusions:Mini-open DAA is a safe and effective procedure for the treatment of FAI that gives good relief of symptoms and allows a successful return to preoperative activity levels. Further research with a longer followup period is needed to evaluate the influence of surgery on natural history of FAI.

Bony Morphology of Femoroacetabular Impingement in Young Female Dancers and Single-Sport Athletes.

Background:Femoroacetabular impingement (FAI) is a painful and limiting condition of the hip that is often seen in young athletes. Previous studies have reported a higher prevalence of this disorder in male athletes, but data on the structural morphology of adolescent and young adult female athletes, specifically those involved in dance, are lacking.Purpose:(1) To investigate the radiographic morphology of FAI deformities in adolescent and young adult female single-sport dance and nondance athletes and (2) to examine the differences in the radiographic findings between these 2 groups.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A retrospective chart review of 56 female single-sport athletes 10 to 21 years of age with a diagnosis of FAI within a single-sports medicine division of a pediatric academic medical center was performed. Acetabular index (AI), lateral center-edge angle (LCEA), crossover sign, and ischial spine sign were measured bilaterally on anteroposterior radiographs; alpha angle (AA) was measured on lateral films, and anterior center-edge angle (ACEA) was measured on false-profile films. Independent t tests and Mann-Whitney U tests were used to compare mean angle measurements between dance and nondance athletes. Dichotomized categorical variables and crossover and ischial spine signs were analyzed between dance and nondance athletes by applying a chi-square test. Statistical significance was set as P < .05 a priori.Results:Significant differences in angle measurements were noted. AA was significantly lower in the dancers compared with the nondance athlete group (49.5° ± 6.0° vs 53.9° ± 7.3°, P = .001). The LCEA and ACEA of dance athletes were significantly greater compared with nondance athletes (33.8° ± 6.7° vs 30.9° ± 5.8° [P = .016] and 36.0° ± 8.1° vs 32.3° ± 7.0° [P = .035], respectively). No significant difference in AI was seen between the 2 cohorts (5.0° ± 4.0° for dancers vs 5.9° ± 3.4° for nondancers, P = .195).Conclusion:Significant differences existed in the radiographic bony morphology of young female single-sport dance athletes compared with nondance athletes with FAI. In dance athletes, symptoms were seen in the setting of normal bony morphology.

The validity and accuracy of MRI arthrogram in the assessment of painful articular disorders of the hip.

The assessment of a patient with chronic hip pain can be challenging. The differential diagnosis of intra-articular pathology causing hip pain can be diverse. These includes conditions such as osteoarthritis, fracture, and avascular necrosis, synovitis, loose bodies, labral tears, articular pathology and, femoro-acetabular impingement. Magnetic resonance imaging (MRI) arthrography of the hip has been widely used now for diagnosis of articular pathology of the hip. A retrospective analysis of 113 patients who had MRI arthrogram and who underwent hip arthroscopy was included in the study. The MRI arthrogram was performed using gadolinium injection and reported by a single radiologist. The findings were then compared to that found on arthroscopy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and 95% confidence interval were calculated for each pathology. Labral tear-sensitivity 84% (74.3-90.5), specificity 64% (40.7-82.8), PPV 91% (82.1-95.8), NPV 48% (29.5-67.5), accuracy 80%. Delamination -sensitivity 7% (0.8-22.1), specificity 98% (91.6-99.7), PPV 50% (6.8-93.2), NPV 74% (65.1-82.2) and accuracy 39%. Chondral changes-sensitivity 25% (13.3-38.9), specificity 83% (71.3-91.1), PPV 52% (30.6-73.2), NPV 59% (48.0-69.2) and accuracy 58%. Femoro-acetabular impingement (CAM deformity)-sensitivity 34% (19.6-51.4), specificity 83% (72.2-90.4), PPV 50% (29.9-70.1), NPV 71% (60.6-80.5) and accuracy 66%. Synovitis-sensitivity 11% (2.3-28.2), specificity 99% (93.6-100), PPV 75% (19.4-99.4), NPV 77% (68.1-84.6) and accuracy 77%. Our study conclusions are MRI arthrogram is a useful investigation tool in detecting labral tears, it is also helpful in the diagnosis of femoro-acetabular impingement. However, when it comes to the diagnosis of chondral changes, defects and cartilage delamination, the sensitivity and accuracy are low.

Radiographic Diagnosis of Pincer-Type Femoroacetabular Impingement: A Systematic Review.

Background:Femoroacetabular impingement (FAI) is a well-recognized condition that causes hip pain and can lead to early osteoarthritis if not managed properly. With the increasing awareness and efficacy of operative treatments for pincer-type FAI, there is a need for consensus on the standardized radiographic diagnosis.Purpose:To perform a systematic review of the evidence regarding imaging modalities and radiographic signs for diagnosing pincer-type FAI.Study Design:Systematic review; Level of evidence, 4.Methods:A literature review was performed in 2016 using the Cochrane, PubMed, and Embase search engines. All articles focusing on a radiographic diagnosis of pincer-type FAI were reviewed. Each of the included 44 articles was assigned the appropriate level of evidence, and the particular radiographic marker and/or type of imaging were also summarized.Results:There were 44 studies included in the final review. Most of the articles were level 4 evidence (26 articles), and there were 12 level 3 and 6 level 2 articles. The crossover sign was the most commonly used radiographic sign (27/44) followed by the lateral center-edge angle (22/44). Anteroposterior (AP) pelvis plain radiographs were the most commonly used imaging modality (33 studies). Poor-quality evidence exists in support of most currently used radiographic markers, including the crossover sign, lateral center-edge angle, posterior wall sign, ischial spine sign, coxa profunda, acetabular protrusion, and acetabular index. There is poor-quality conflicting evidence regarding the use of the herniation pit to diagnose pincer-type FAI. Some novel measurements, such as β-angle, acetabular roof ratio, and acetabular retroversion index, have been proposed, but they also lack support from the literature.Conclusion:No strong evidence exists to support a single best set of current radiographic markers for the diagnosis of pincer-type FAI, largely due to the lack of better quality trials (levels 1 and 2) that compare conventional radiographic findings with the gold standard, which is the intraoperative findings. More sophisticated imaging modalities such as computed tomography and magnetic resonance arthrography are often needed to diagnose pincer-type FAI, and these investigations are relatively accurate in assessing labral pathology or cartilage damage.