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Recent advances in understanding hip joint anatomy and biomechanics have contributed to improvement of diagnosis and treatment decisions for distal causes of deep gluteal syndrome (DGS). Ischiofemoral impingement and hamstrings syndrome are sources of posterior hip pain that can simulate symptoms of DGS. The combination of a comprehensive history and physical examination with imaging and ancillary testing are critical for diagnosis. Six key physical examination tests are described to differentiate distal versus proximal sources of extrapelvic posterior hip pain. Outcomes depend on patient compliance and the understanding of the entire anatomy, biomechanics, clinical presentation, and open versus endoscopic treatment options., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Recent years have witnessed a growing number of people practising sports both at professional and amateur level. This trend led to a progressive rise in the incidence and prevalence of acute and chronic hip damage. The treatment of hip disease in subjects practising sports is a major challenge for the orthopaedic surgeon. The evaluation of patients, in particular those of young age with high functional demands, is inevitably complex and should be performed with a multidisciplinary approach; from a surgical point of view, it is essential to carefully assess whether the indication is towards conservative surgery or hip replacement surgery. The advent of arthroscopic surgery in recent years has allowed us to improve our knowledge of hip joint diseases, such as femoroacetabular impingement that is typical of sports and overuse activity. A correct and early diagnosis of the disease can direct the patient promptly to a conservative surgical treatment that could reduce the progression of degenerative pathology. However, when the joint is permanently damaged, the only reliable solution remains prosthetic surgery, leading to a series of issues that the orthopaedic surgeon should be able to master, leading to a thoughtful decision on, for example, which implant to use, which biomaterials, which surgical approach or which sport to practise after surgery. This supplement contains selected contributions stemming from the work performed by internationally recognised experts in the field and presented during the 1st European Hip Sport Meeting held in Bologna on May 19th, 20th, 2016 that we had the honour to co-chair. We hope that these contributions will help the orthopaedic surgeon, the sports physician and physiotherapist in their day-to-day practice, and will help in fulfilling our ultimate aim to improve the knowledge of the hip pathology related to sports and overuse activities.

Purpose: This international survey was conducted to assess the perceptions of orthopaedic surgeons regarding the diagnosis and management of femoroacetabular impingement (FAI) as well as to explore the current demographic characteristics of surgeons performing FAI surgery., Methods: A survey was developed using previous literature, focus groups, and a sample-to-redundancy strategy. The survey contained 46 questions and was e-mailed to national orthopaedic associations and orthopaedic sports medicine societies for member responses. Members were contacted on multiple occasions to increase the response rate., Results: Nine hundred orthopaedic surgeons from 20 national and international organizations completed the survey. Surgeons responded across 6 continents, 58.2% from developed nations, with 35.4% having sports fellowship training. North American and European surgeons reported significantly greater exposure to hip arthroscopy during residency and fellowship training in comparison to international respondents (48.0% and 44.5% respectively, v 25.6%; P < .001). Surgeons performing a higher volume of FAI surgery (> 100 cases per year) were significantly more likely to have practiced for more than 20 years (odds ratio [OR], 1.91; 95% confidence interval [CI], 1.01 to 3.63), to be practicing at an academic hospital (OR, 2.25; 95% CI, 1.22 to 4.15), and to have formal arthroscopy training (OR, 46.17; 95% CI, 20.28 to 105.15). High-volume surgeons were over two-fold more likely to practice in North America and Europe (OR, 2.26; 95% CI, 1.08 to 4.72)., Conclusions: The exponential rise in the diagnosis and surgical management of FAI appears to be driven largely by experienced surgeons in developed nations. Significant variability exists regarding the diagnosis and management of FAI. Our analysis suggests that although FAI management is early in the innovation cycle, we are at a tipping point toward wider uptake and use., (Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Femoroacetabular impingement is increasingly recognized as a cause of hip pain but its incidence after an innominate osteotomy for the correction of acetabular dysplasia has not been determined. This information would be essential for the orthopaedic surgeon because it has the potential to produce a poor outcome in the long term when trying to balance acetabular instability and overcorrection., Questions/purposes: The purposes of our study were (1) to determine the frequency with which clinically relevant femoroacetabular impingement (FAI) occurs after an innominate osteotomy for the treatment of acetabular dysplasia; (2) to determine risk factors for the development of FAI; and (3) to compare postoperative radiographic and clinical outcomes in patients having undergone an innominate osteotomy for the correction of acetabular dysplasia both with and without FAI., Methods: This was a retrospective review of 154 hips (132 patients) that had undergone an innominate osteotomy for acetabular dysplasia and were evaluated at a minimum followup of 10 years (mean = 12 years). Mean age at the time of surgery was 3 years, 114 hips had a concomitant open reduction, and 54 hips also had femoral shortening. One hundred eight hips had a Salter osteotomy and 46 had a Pemberton osteotomy. Radiographs were analyzed to determine the lateral center-edge angle (CE angle) and the presence of a crossover sign. The diagnosis of FAI was established when the CE angle was greater than 40°, there was a positive crossover sign, and the patient had groin pain when flexing the hip less than 90°. Comparisons between nonparametric variables were performed with a Mann-Whitney's U test. Categorical variables were compared with a chi-square test. Change in acetabular index (correction) was dichotomized considering 20° of correction as the cutoff point. Association is presented as odds ratio (95% confidence interval), and logistic regression was performed., Results: According to our criteria, 18 of 154 hips had FAI (12%). Of the 18 patients with FAI, 10 had undergone a Pemberton osteotomy (10 of 46 [22%]) and eight a Salter osteotomy (eight of 108 [7%]). A change in the postoperative acetabular index greater than 20° was associated with a greater likelihood of developing FAI. The mean postoperative acetabular index was lower for the group with FAI, for whom it was 20°, compared with the group without FAI, for whom it was 27° (p = 0.04). The mean Iowa Hip Score for the group with FAI was 85, whereas for those without FAI, it was 93 (p = 0.03)., Conclusions: FAI is not common after an innominate osteotomy for the treatment of acetabular dysplasia; however, overcorrection is related to a higher incidence. When FAI is present, it can affect the outcome. Overcorrection should be avoided when performing an innominate osteotomy for the treatment of acetabular dysplasia because it can create iatrogenic FAI and have an adverse effect on outcome., Level of Evidence: Level III, therapeutic study.

Purpose: The head-neck offset described by Eijer et al. (eHNO), which is used to diagnose anterior femoro-acetabular impingement (FAI), can be difficult to measure. The aim of this study was to verify if a modified head-neck offset (mHNO) provides more accurate and reproducible values than those of the eHNO., Methods: The eHNO, mHNO, cephalic radius and alpha angle were measured on frog-leg radiographs of a group of patients with FAI and a control group (T); three independent reviewers measured the 50 hips in each group twice. The comparison of the two HNOs focused on reproducibility (intraclass correlation coefficient), validity (correlation with alpha angle), practical utility (difference between means in the FAI and control groups) and accuracy of the diagnostic thresholds., Results: The mHNO had better reproducibility (p < 0.05) within and between observers in all study subjects than that of the eHNO (0.938 and 0.979 vs 0.881 and 0.904). The correlation with the alpha angle was also better (p < 0.05) for the mHNO than that for the eHNO. The diagnostic performances of the mHNO and mAOR thresholds were higher than those of the eHNO, eAOR and alpha angle., Conclusions: The new HNO is easier to measure, more reproducible and more accurate. A modified HNO <5 mm and a modified AOR <0.100 on the frog-leg view argued in favour of a pathological cam-type head-neck junction.

Femoral acetabular impingement (FAI) has emerged as one of the more commonly recognized intraarticular hip pathologies and is often accompanied with a labral tear. The understanding of the clinical characteristics of individuals with symptomatic FAI has evolved over the past several years due to emerging research. As research progresses, there is often a gap in translating the current evidence to clinical practice. This manuscript presents the latest evidence underpinning the clinical presentation of FAI and labral tears. Evidence is presented within the context of bridging the latest research and clinical practice., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Surgical treatment of femoroacetabular impingement (FAI) is nowadays achieved by either open surgical hip dislocation or hip arthroscopy. However, drawbacks of both procedures include the invasiveness of the open procedure and a high learning curve to successfully perform arthroscopic treatment. In our institution, we established a minimally invasive, arthroscopically assisted, antero-lateral approach for the correction of cam type FAI., Objectives: The goal of the study was to describe the surgical technique and highlight the short-term clinical outcome in a consecutive series of patients operated between 2011 and 2014 in our institution., Materials and Methods: In total, 77 patients were included in this study. The patients were allocated to two groups (Toennis = 0: Group I; Toennis 1 and 2: Group II). Clinical and radiographic follow up was obtained at 6 and 12 weeks postoperatively. Clinical outcome was assessed using the Hip-Outcome-Score., Results: The mean age of patients in Group I was 25 (16-48) years and in Group II 38 (17-50) years respectively. Internal rotation (IR) in 90° flexion increased by 11 degrees from pre- to postoperatively in Group I (p < 0.001) and by 14° in Group II (p < 0.001). The Hip Outcome Score revealed the ability to perform sports with reduced pain at three months follow up. Subjectively, all patients benefitted in terms of pain and hip function in both groups (p < 0.001). There were no complications with long-term morbidity during the perioperative course., Conclusion: Arthroscopically assisted cam resection using a minimally invasive anterolateral approach is a safe technique for the treatment of FAI. At short term follow up, nearly all operated patients seem to benefit in terms of pain and hip function. The influence of progression of osteoarthritis still has to be shown.

Background: Instability is a common cause of revision hip arthroplasty and is frequently due to improper component placement and subsequent component impingement. Impingement of the greater trochanter upon the anterior inferior iliac spine (AIIS) has been described as a cause of symptomatic femoroacetabular impingement (FAI), but has never been described as a cause of instability following total hip arthroplasty (THA)., Case Review: We present 2 cases of patients undergoing THA. Each patient was evaluated preoperatively and found to have a prominent AIIS, which was concerning due to it overhanging the anterolateral acetabular lip. Both patients had intraoperative posterior instability of their THA, the cause of which was determined to be impingement of the greater trochanter upon a prominent AIIS. Open resection of the AIIS was performed with subsequent resolution of impingement., Literature Review: AIIS impingement has been reported as a cause of symptomatic FAI. In these case reports, open or arthroscopic resection of the AIIS resulted in resolution of symptoms. Morphologically distinct subtypes of the AIIS have been previously described based upon computed tomography, and some subtypes are associated with a high risk of impingement in the native hip. No previous studies have described this phenomenon in the setting of THA., Clinical Relevance: Instability is a common cause of revision THA. Impingement of the greater trochanter upon a prominent AIIS is a previously unreported cause of THA instability which can be addressed with intraoperative resection of the AIIS with good result.

Objective: The main purpose of the present study was to determine the prevalence of FAI among patients who underwent total hip arthroplasty (THA) with the diagnosis of end-stage osteoarthritis (OA) of the hip joint in a tertiary referral centre., Design: A retrospective search of the institutional archive database for patients who had undergone THA between the years 2005 and 2010 was conducted with the analysis of the recorded radiographic images. A total of 1,004 patients including 690 (68.7%) females and 314 (31.3%) males were identified. All radiographs were reviewed by 3 of the authors. Intra- and interobserver consistencies were calculated. The prevalence of femeroacetabular impingement (FAI) as a predisposing diagnosis resulting in end-stage degenerative joint disease treated with THA was determined., Results: The most common diagnosis was developmental dysplasia of the hip (DDH). The predisposing aetiologic factor leading to end-stage degenerative hip disease treated with THA was undetermined for 26 patients (2.6%). The number of patients who were diagnosed as cam-type FAI by all of the observers was 83, whereas it was 16 for pincer-type FAI. Interobserver agreement was very high in the evaluation of the stated ethiologies of hip osteoarthritis. The contingency coefficient for the diagnosis of FAI was 0.71 between observers., Conclusions: Our study may be a reference for further investigations to develop a better understanding of the underlying pathological factors in patients undergoing THA due to end-stage OA of the hip joint.

Background: There is a paucity of data on the results of reverse (anteverting) periacetabular osteotomy (RPAO) for treatment of femoroacetabular impingement (FAI) secondary to acetabular retroversion., Purpose: To evaluate the midterm outcomes of RPAO for FAI secondary to acetabular retroversion in those with and without hip dysplasia., Study Design: Cohort study; Level of evidence, 3., Methods: A retrospective review identified RPAOs performed on patients with acetabular retroversion in isolation or in the setting of dysplasia (lateral center-edge angle [LCEA] ≤19°). Acetabular retroversion with FAI was diagnosed clinically and radiographically, with a positive crossover and posterior wall signs on pelvic radiographs. Twenty-three patients (30 hips) met the inclusion criteria; 20 hips with isolated retroversion and 10 hips with retroversion and hip dysplasia. The average age at the time of the procedure was 26 years (range, 13-45 years). The average length of follow-up was 5 years (range, 2-19 years). Harris Hip Score (HHS) and radiographs were evaluated preoperatively and at last follow-up., Results: The mean preoperative LCEA was 31° (range, 22°-49°) in the isolated retroversion group and 9° (range, -4° to 17°) in the dysplastic group. Postoperatively, the LCEA in the dysplastic group increased to 35° (range, 15°-46°) (P = .0001). The crossover sign corrected in 55% (11/20) of the isolated retroversion group and 80% (8/10) of the dysplastic group. The acetabular index (mean ± SD) improved from 1.3 ± 0.3 to 1.7 ± 0.6 (P = .0001), indicating improved anteversion. At the latest follow-up, the average HHS in the isolated retroversion group increased from 58 preoperatively (range, 23-77) to 93 (range, 68-100) (P = .0001); the HHS in the dysplastic group improved from 49 (range, 20-74) to 92 (range, 77-100) (P < .0001). Complication rates were similar in both groups. Excluding hardware removal, additional surgeries were performed in 13% (4/30)., Conclusion: RPAO performed for FAI in the young patient with isolated acetabular retroversion or retroversion in the setting of dysplasia successfully improved clinical and radiographic results at mid- to long-term follow-up., (© 2015 The Author(s).)

Background: As the prevalence of hip pathology in the younger athletic population rises, the medical community continues to investigate effective intervention options. Femoracetabular impingement is the morphologically abnormal articulation of the femoral head against the acetabulum, and often implicated in pre-arthritic hip conditions of musculoskeletal nature. Arthroscopic surgical decompression and non-surgical rehabilitation programs focused on strengthening and stability are common interventions. However, they have never been directly compared in clinical trials. The primary purpose of this study will be to assess the difference in outcomes between these 2 commonly utilized interventions for femoracetabular impingement., Methods: The study will be a single site, non-inferiority, randomized controlled trial comparing two different treatment approaches (surgical and nonsurgical) for FAI. The enrollment goal is for a total of 80 subjects with a diagnosis of Femoracetabular impingement that are surgical candidates and have failed 6 weeks of conservative treatment. This will be a convenience sample of consecutive patients that are Tricare beneficiaries and seeking care at Madigan Army Medical Center. Patients that meet the criteria will be screened, provide written consent before enrollment, and then randomized into one of two arms (Group I = hip arthroscopy, Group II = physical therapy). Group I will undergo hip arthroscopy with or without labral repair. Group II will follow an impairment based physical therapy program consisting of 2 sessions per week for 6 weeks. The primary outcome will be the Hip Outcome Score and secondary measures will include the International Hip Outcome Tool and the Global Rating of Change. Measures will be taken at baseline, 6 months, 1 and 2 years. Hip-related healthcare utilization between both groups will also be assessed at the end of 2 years., Discussion: The current evidence to support both surgical and conservative interventions for femoroacetabular impingement is based on low-level research. To date, none of these interventions have been directly compared in a randomized clinical trial. Clinical trials are needed to help establish the value of these interventions in the management of femoracetabular impingement and to help define appropriate clinical pathways., Trial Registration: NCT01993615 30 October 2013.

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.

Open MRI in functional positions has potential to directly and non-invasively assess cam femoroacetabular impingement (FAI). Our objective was to investigate whether open MRI can depict intrusion of the cam deformity into the intra-articular joint space, and whether intrusion is associated with elevated acetabular contact force. Cadaver hips (9 cam; 3 controls) were positioned in an anterior impingement posture and imaged using open MRI with multi-planar reformatting. The β-angle (describing clearance between the femoral neck and acetabulum) was measured around the entire circumference of the femoral neck. We defined a binary "MRI cam-intrusion sign" (positive if β < 0°). We then instrumented each hip with a piezoresistive sensor and conducted six repeated positioning trials, measuring acetabular contact force (F). We defined a binary "contact-force sign" (positive if F > 20N). Cam hips were more likely than controls to have both a positive MRI cam-intrusion sign (p = 0.0182, Fisher's exact test) and positive contact-force sign (p = 0.0083), which represents direct experimental evidence for cam intrusion. There was also a relationship between the MRI cam-intrusion sign and contact-force sign (p = 0.033), representing a link between imaging and mechanics. Our findings indicate that open MRI has significant potential for in vivo investigation of the cam FAI mechanism., (© 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: Orientation abnormalities of the acetabulum and femur have been implicated in early-onset coxarthrosis. The purpose of this study was to identify clinical examination findings predictive of such hip morphologies., Methods: A consecutive cohort of 221 patients (442 hips) undergoing hip arthroscopy was included. Demographic characteristics including age, diagnosis, sex, height, weight, body mass index (BMI), and physical activity level were recorded. Passive range of motion was measured for all hips. Preoperative computed tomography scans were utilized to measure femoral torsion and central acetabular version, and a combined femoral torsion-acetabular version (COTAV) index was defined as their sum., Results: The study cohort comprised 221 patients (sixty-four males, 157 females) with a mean age of 32.5 years and mean BMI of 24.2 kg/m(2). Overall, hips with femoral antetorsion and acetabular anteversion exhibited the greatest internal rotation range of motion at a neutral hip position (mean, 44.2°), whereas hips with femoral retrotorsion and acetabular retroversion demonstrated the lowest corresponding value (20.1°; p < 0.001). Femoral torsion was significantly associated with female sex (p < 0.001), BMI (p < 0.001), and presence of pathology corresponding to cam-type femoroacetabular impingement (FAI) (p = 0.044). Central acetabular version was significantly associated with age (p = 0.021), female sex (p < 0.001), and absence of mixed-type FAI pathology (p = 0.025). Increasing age and internal rotation range of motion at a neutral hip position were the most significant predictors of an increased COTAV index., Conclusions: This study confirmed that passive hip range of motion significantly predicts combined femoral torsion and central acetabular version. Accurate clinical assessment of the COTAV index may inform surgical decision-making in hip preservation surgery., (Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.)

Femoro-acetabular impingement (FAI) is increasingly recognized as an important cause of hip pain in the young adult. However, the methods of evaluating the efficacy of surgical intervention are often not validated and/or inconsistently reported. Important clinical, gait, radiographic and biomarker outcomes are discussed. This article (1) presents the rationale for considering a composite outcome for FAI patients; (2) examines a variety of important end points currently used to evaluate FAI surgery; (3) discusses a strategy to generate a composite outcome by combining these end points; and (4) highlights the challenges and current areas of controversy that such an approach to evaluating symptomatic FAI patients may present.

Objective: To investigate the early effectiveness of arthroscope for femoroacetabular impingement (FAI)., Methods: Between February 2012 and June 2014, 17 patients (17 hips) with FAI were treated under arthroscope. Of 17 patients, 12 were male and 5 were female, aged 18-60 years (mean, 37.2 years); 9 left hips and 8 right hips were involved. All patients had pain in groin for 12-24 months (mean, 15 months), no limited activity of the hip and obvious provocative pain in full flexion and internal rotation. The results of impingement test and the Faber test were all positive. According to X-ray examination, 8 cases were at early stage, 8 cases at middle stage, and 1 case at late stage; according to anatomical morphology, 6 cases were rated as cam-type impingement, 3 cases as pincer-type impingement, and 8 cases as mixed type. Based on impingement type, arthroscopic femoroplasty, arthroscopic acetabuloplasty, and a combination of arthroscopic femoroplasty and acetabuloplasty were performed on 6, 3, and 8 patients respectively., Results: Primary healing of incision was obtained. One patient had numbness in the lateral thigh, and symptom disappeared after 2 weeks. All cases were followed up 1-2 years (mean, 1.3 years). All patients obtained obvious hip pain relief. The postoperative Harris scores were significantly increased to 91.44 ± 1.98 at 6 weeks, 95.83 ± 0.53 at 3 months, and 95.33 ± 2.43 at 1 year from preoperative 79.01 ± 3.20 (P < 0.05), and the scores at 3 months and at 1 year were significantly higher than that at 6 weeks (P < 0.05), but there was no significant difference between at 3 months and at 1 year (P > 0.05)., Conclusion: Arthroscope treatment of FAI can obviously relief hip pain. The key points for acquiring satisfactory early effectiveness are definite diagnosis, early detection, and minimally invasive treatment.

Impingement resulting from a cam deformity may cause pain, limit the hip joint range of motion (RoM) and lead to osteoarthritis. We have previously developed FeMorph software to quantify and plan corrective surgery and predict hip RoM post surgery. This study aimed to validate the software and evaluate the influence of the acetabular labrum on hip RoM. Computed tomography data from 92 femur-pelvis pairs were analysed in conjunction with the inter/intra-observer reliability. Four cadaveric hips were dissected, and the three-dimensional (3D) shape and size of the acetabular labrum for these hips was obtained using laser scan. The influence of the acetabular labrum in the RoM and subsequent planning for corrective surgery were then evaluated in cadavers for models with and without a labrum, and used as a first step towards validation of FeMorph RoM prediction. FeMorph was successfully used to model cam deformities and plan corrective surgery. Three-dimensional alpha angles were reduced to below 50° after virtual surgery without an excessive reduction in femoral neck cross-sectional area, which could increase fracture risk. A mean increase of 8° ± 2° in permitted internal rotation was observed during impingement testing following removal of the labrum. FeMorph provides a reliable and useful method to model and plan cam deformity correction. This study indicates that the presence of the labrum is responsible for a substantial decrease in permitted internal rotation at the hip joint. This has implications for surgical planning models which often only account for bony impingement.

Acute hip pain is a common presenting complaint amongst the military population. It can present in a variety of ways, with a broad range of differential diagnoses to consider. Most cases of acute hip pain in military patients tend to be traumatic in origin. Pathology within the hip can be a diagnostic challenge, as symptoms often overlap between differential diagnoses and examination findings are not always sensitive or specific. Any hip injury will potentially downgrade a military patient and can also be a significant cause of long-term morbidity. Being able to manage the patient with acute hip pain effectively will ensure that patients spend less time in the diagnostic chain and reach the definitive treatment they require to continue to carry out their primary role. This paper describes how best to manage military patients who present with acute hip pain. It covers the diagnostic challenges faced by clinicians, the differential diagnoses of acute hip pain and describes the management of some common injuries of the hip: tears of the acetabular labrum and femoral neck stress fractures.

Complications after hip arthroscopy vary in frequency and severity, even for experienced surgeons. It is important for surgeons to be aware of some of the more dramatic, often unusual, and always memorable (nightmarish) complications of hip arthroscopy and understand how they are caused, how they can be treated, and how they can be prevented.

Objective: To outline the clinical presentation, physical examination findings, diagnostic criteria, and management options of femoroacetabular impingement (FAI)., Sources of Information: PubMed was searched for relevant articles regarding the pathogenesis, diagnosis, treatment, and prognosis of FAI., Main Message: In recent years, FAI has been increasingly recognized as a potential precursor and an important contributor to hip pain in the adult population and idiopathic hip osteoarthritis later in life. Femoroacetabular impingement is a collection of bony morphologic abnormalities of the hip joint that result in abnormal contact during motion. Cam-type FAI relates to a non-spherical osseous prominence of the proximal femoral neck or head-neck junction. Pincer-type FAI relates to excessive acetabular coverage over the femoral head, which can occur owing to several morphologic variants. Patients with FAI present with chronic, deep, or aching anterior groin pain most commonly in the sitting position, or during or after activity. Patients might also experience occasional sharp pains during activity. A thorough history should be taken that includes incidence of trauma and exercise frequency. A physical examination should be performed that includes a full hip, low back, and abdominal examination to assess for alternate causes of anterior groin pain. Diagnosis of FAI should be confirmed with radiography. Femoroacetabular impingement can be managed conservatively with rest, modification of activities, medications, and physiotherapy, or it can be treated surgically., Conclusion: Femoroacetabular impingement is an important cause of anterior groin pain. Early recognition and intervention by the primary care provider might be critical to alleviating morbidity and preventing FAI progression., (Copyright© the College of Family Physicians of Canada.)

Introduction: Minimal bone changes in the acetabulum and/or proximal femur, through mechanism known as femoroacetabular impingement, during flexion, adduction and internal rotation lead to early contact between femoral head-neck junction and acetabular brim, in anterosuperior region. Each additional pathological substrate which further decreases specified clearance provokes earlier onset of femoroacetabular impingement symptoms., Case Report: We presented a 20-year-old male patient with groin pain, limping, positive impingement test, radiological signs of mixed form of femoroacetabular impingement and unrecognized chronic hypertrophic synovitis with earlier development of clinical hip symptoms than it has been expected. Open surgery of the left hip was done. Two years after the surgery, patient was asymptomatic, painless, and free of motion, with stable x-rays., Conclusion: Hypertrophic synovial tissue further reduces the distance between the femoral head-neck junction and the acetabulum, leading to the earlier onset of femoroacetabular impingement symptoms. Surgical treatment is the method of choice.

Objective: To examine the effect of total hip arthroplasty (THA) on ischiofemoral (IF) and quadratus femoris (QF) spaces with the hypothesis that THA does not affect ischiofemoral relationships., Materials and Methods: The study was IRB approved and complied with HIPAA guidelines. We identified consecutive MR examinations (pelvis and/or hip) obtained at our institution in adults (≥18 years old) screened for THA-related complications. Native hips from the same individuals served as controls. We collected medical record data including age, gender, surgical history, and THA designs. Two radiologists independently measured the IF-RAD and IF-MRI (IF space on radiographs and MR imaging, respectively) and QF space (on MR imaging). Groups were compared using ANCOVA controlled for gender., Results: The study group comprised 250 hips (132 subjects; 162 post-THA and 88 native hips). Subjects were aged 59 ± 10 years, with 66 males and 66 females. Comparison of IF-MRI and QF spaces between native and post-THA hips showed no differences (P > 0.12) and IF-RAD was higher in post-THA subjects (P = 0.01). No differences in the IF-MRI and QF spaces were present between native hips and different THA designs (P > 0.4). IF-RAD of metal-on-metal THA was higher than that of native hips (P = 0.01) and trended higher than ceramic-on-polyethylene THA (P = 0.08), with the remaining comparisons showing no significant differences (P > 0.4)., Conclusions: Radiographic- and MRI-based measures in patients with standard THA do not show narrowing of IF and QF spaces.

Femoroacetabular impingement (FAI) has been identified as a potential cause of hip osteoarthritis. The goal of FAI surgery is to relieve pain, and hopefully delay or prevent osteoarthritis of the hip. Several studies have now demonstrated favorable clinical outcomes after arthroscopic and open surgical correction of symptomatic FAI. The concept is restoration of normal hip anatomy may result in improved biomechanical function and kinematics of the hip, which may prevent or delay the progression of osteoarthritis. Although many clinical studies demonstrate restoration of "normal" anatomy, there are few studies evaluating improvement of biomechanics and function. To date, only 5 studies have been published in the English literature that study biomechanics and/or kinematics of the hip both preoperatively and postoperatively. At this point in the understanding of FAI, critical analysis of the literature suggests that FAI surgery can improve several parameters of biomechanical hip function. However, the impact of these improved biomechanics on the natural history and progression of degenerative changes in patients that are treated for symptomatic FAI has not been demonstrated.

Background: The iliocapsularis muscle is an anterior hip structure that appears to function as a stabilizer in normal hips. Previous studies have shown that the iliocapsularis is hypertrophied in developmental dysplasia of the hip (DDH). An easy MR-based measurement of the ratio of the size of the iliocapsularis to that of adjacent anatomical structures such as the rectus femoris muscle might be helpful in everyday clinical use., Questions/purposes: We asked (1) whether the iliocapsularis-to-rectus-femoris ratio for cross-sectional area, thickness, width, and circumference is increased in DDH when compared with hips with acetabular overcoverage or normal hips; and (2) what is the diagnostic performance of these ratios to distinguish dysplastic from pincer hips?, Methods: We retrospectively compared the anatomy of the iliocapsularis muscle between two study groups with symptomatic hips with different acetabular coverage and a control group with asymptomatic hips. The study groups were selected from a series of patients seen at the outpatient clinic for DDH or femoroacetabular impingement. The allocation to a study group was based on conventional radiographs: the dysplasia group was defined by a lateral center-edge (LCE) angle of < 25° with a minimal acetabular index of 14° and consisted of 45 patients (45 hips); the pincer group was defined by an LCE angle exceeding 39° and consisted of 37 patients (40 hips). The control group consisted of 30 asymptomatic hips (26 patients) with MRIs performed for nonorthopaedic reasons. The anatomy of the iliocapsularis and rectus femoris muscle was evaluated using MR arthrography of the hip and the following parameters: cross-sectional area, thickness, width, and circumference. The iliocapsularis-to-rectus-femoris ratio of these four anatomical parameters was then compared between the two study groups and the control group. The diagnostic performance of these ratios to distinguish dysplasia from protrusio was evaluated by calculating receiver operating characteristic (ROC) curves and the positive predictive value (PPV) for a ratio > 1. Presence and absence of DDH (ground truth) were determined on plain radiographs using the previously mentioned radiographic parameters. Evaluation of radiographs and MRIs was performed in a blinded fashion. The PPV was chosen because it indicates how likely a hip is dysplastic if the iliocapsularis-to-rectus-femoris ratio was > 1., Results: The iliocapsularis-to-rectus-femoris ratio for cross-sectional area, thickness, width, and circumference was increased in hips with radiographic evidence of DDH (ratios ranging from 1.31 to 1.35) compared with pincer (ratios ranging from 0.71 to 0.90; p < 0.001) and compared with the control group, the ratio of cross-sectional area, thickness, width, and circumference was increased (ratios ranging from 1.10 to 1.15; p ranging from 0.002 to 0.039). The area under the ROC curve ranged from 0.781 to 0.852. For a one-to-one iliocapsularis-to-rectus-femoris ratio, the PPV was 89% (95% confidence interval [CI], 73%-96%) for cross-sectional area, 77% (95% CI, 61%-88%) for thickness, 83% (95% CI, 67%-92%) for width, and 82% (95% CI, 67%-91%) for circumference., Conclusions: The iliocapsularis-to-rectus-femoris ratio seems to be a valuable secondary sign of DDH. This parameter can be used as an adjunct for clinical decision-making in hips with borderline hip dysplasia and a concomitant cam-type deformity to identify the predominant pathology. Future studies will need to prove this finding can help clinicians determine whether the borderline dysplasia accounts for the hip symptoms with which the patient presents., Level of Evidence: Level III, prognostic study.

Purpose: As the body of literature on femoroacetabular impingement (FAI) continues to grow, clinicians turn to systematic reviews to remain current with the best available evidence. The quality of systematic reviews in the FAI literature is currently unknown. The goal of this study was to assess the quality of the reporting of systematic reviews addressing FAI over the last 11 years (2003-2014) and to identify the specific methodological shortcomings and strengths., Methods: A search of the electronic databases, MEDLINE, EMBASE and PubMed, was performed to identify relevant systematic reviews. Methodological quality was assessed by two reviewers using the revised assessment of multiple systematic reviews (R-AMSTAR) scoring tool. An intraclass correlation coefficient (ICC) with 95 % confidence intervals (CI) was used to determine agreement between reviewers on R-AMSTAR quality scores., Results: A total of 22 systematic reviews were assessed for methodological quality. The mean consensus R-AMSTAR score across all studies was 26.7 out of 40.0, indicating fair methodological quality. An ICC of 0.931, 95 % CI 0.843-0.971 indicated excellent agreement between reviewers during the scoring process., Conclusions: The systematic reviews addressing FAI are generally of fair methodological quality. Use of tools such as the R-AMSTAR score or PRISMA guidelines while designing future systematic reviews can assist in eliminating methodological shortcomings identified in this review. These shortcomings need to be kept in mind by clinicians when applying the current literature to their patient populations and making treatment decisions. Systematic reviews of highest methodological quality should be used by clinicians when possible to answer clinical questions.

Aims: The aim of this study was to establish preoperative factors associated with a good outcome in the surgical treatment of femoroacetabular impingement., Methods: A prospective study including 253 consecutive patients (280 hips) was carried out. We defined a "good" score as one which had either a 20 point improvement from preoperative to 12 months postoperative follow-up, or a score of over 80 points at 12-month follow-up in either the Non Arthritic Hip Score (NAHS) or Modified Harris Hip Score (MHHS). We analysed 9 potential predictors of 12-month postoperative outcome: patient age, gender, BMI, surgery type (primary/revision), preoperative anxiety level, preoperative labro-chondral damage, operative side, patients belonging to the armed forces and patients being treated under the workers compensation scheme. We used logistic regression (multivariable, adjusted) and, Fisher's exact test and student t test (bivariate, unadjusted) to analyse the data., Results: A strong association between workers' compensation status and not achieving a good outcome following arthroscopic surgery for femoroacetabular impingement (odds ratio 3.84, 95% CI, 0.13-0.51, P&lt;0.0001) was found. A negative effect on postoperative outcome was also observed with increased BMI, although this association was modest (odds ratio 1.06, 95% CI, 0.87-0.99 p = 0.03). Patients with a higher preoperative score did better at 12 months than the rest of the cohort., Conclusions: The data from this study may be useful for both patient and physician to consider when deciding on a suitable treatment in potential surgical candidates suffering from femoroacetabular impingement.

Symptomatic femoroacetabular impingement (FAI) predisposes patients to developing early osteoarthritis. This article reviews the criteria for diagnosing FAI, management strategies, and when to refer patients to an orthopedic provider for further evaluation and possible surgical intervention.

Background: We sought to identify, which patient and radiographic factors at preoperative and 1-year follow up will predict patient symptom relief at mid-term., Materials and Methods: A total of 50 hips in 47 patients with symptomatic FAI were included in this retrospective study. We stratified the hips into "success" and "failure" groups based on the change from baseline to mid-term follow up WOMAC pain score (mean follow up of 5.8 years). An attempt was made to identify factors that are predictive of mid-term outcome among preoperative radiographic measures, dGEMRIC index, range of motion and WOMAC score as well as 1-year follow-up range of motion, radiographic measures, and WOMAC pain scores., Results: At 1-year follow up, the success rate was 72% (36/50) and at mid-term follow the success rate increased to 82% (41/50). There were no significant associations between mid-term pain scores and baseline factors (all p-values ≥0.10). One-year pain score and hip internal rotation was associated with poor mid-term pain scores but only the 1-year pain score was associated with the mid-term success/failure outcome., Conclusions: We did not identify clear preoperative predictors of mid-term results but patients with poor pain scores and limited hip internal rotation at 1-year follow-up are less likely to do well at mid-term.

Purpose: To develop a simplified method to define a clinically relevant subregion in the course of arthroscopic treatment of femoroacetabular impingement (FAI) using T2 mapping in patients and asymptomatic volunteers. Additionally, we sought to compare the lateral and medial subregion values in asymptomatic volunteers and in patients presenting with FAI. Finally, we wanted to investigate possible associations between patients' T2 mapping values and demographic variables-i.e., alpha angle, age, sex, and body mass index (BMI)., Methods: Twenty-five asymptomatic volunteers and 23 consecutive symptomatic patients with FAI (cam or mixed type) were prospectively enrolled and evaluated with a sagittal T2 mapping sequence. The weight-bearing region of the acetabular and femoral cartilage was manually segmented and divided into medial and lateral subregions. Median T2 values were determined, and patient characteristics were assessed as potential predictors of T2 values., Results: T2 values in the lateral portion of the acetabulum were lower than in the medial portion for both asymptomatic volunteers (43 v 53 ms; P < .001) and patients with FAI (42 v 49 ms; P = .016). The medial acetabulum (MA) of asymptomatic volunteers had higher T2 values than those of the FAI group (53 v 49 ms; P = .040). The lateral-minus-medial difference was significantly larger among asymptomatic volunteers than in patients with FAI (P = .047). Patients with FAI had higher alpha angles than those of the asymptomatic volunteers, but no other associations with patient characteristics were observed., Conclusions: This study's findings suggest that there are differences in cartilage T2 mapping values between medial and lateral weight-bearing aspects of the hip and may expand the application and usefulness of biochemical magnetic resonance imaging (MRI) techniques, specifically T2 mapping, in the diagnosis of hip cartilage damage with the evaluation of clinically relevant subregions. When comparing asymptomatic volunteers and patients with FAI presenting with cam or mixed type deformity, we observed a significant contrast between the T2 mapping values of the lateral and medial portions of the weight-bearing zone of the acetabular cartilage, whereas such contrast was not observed when zone 3 was analyzed as a whole., Level of Evidence: Level III, development of diagnostic criteria on the basis of consecutive patients with a universally applied reference gold standard., (Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: The epidemiology of femoroacetabular impingement (FAI) is important but incompletely understood, because most reports arise from symptomatic populations. Investigating the prevalence of FAI in a community-based cohort could help us better understand its epidemiology and in particular the degree to which it might or might not be associated with hip pain., Questions/purposes: The purposes of this study were (1) to evaluate the proportion of older (≥65 years of age) men with morphologic abnormalities consistent with FAI; and (2) to assess the association of the morphologic abnormalities with prevalent radiographic hip osteoarthritis (OA) and hip pain., Methods: Anteroposterior radiographs were obtained in 4140 subjects (mean age±SD, 77±5 years) from the Osteoporotic Fractures in Men study. We assessed each hip for cam, pincer, and mixed FAI types using validated radiographic definitions. Both intra- and interobserver reproducibility were >0.9. Radiographic hip OA was assessed by an expert reader (intraobserver reproducibility, 0.7-0.8) using validated methods, and summary grades of 2 or greater (on a scale from 0 to 4) were used to define radiographic hip OA. Covariates including hip pain in the last 30 days were collected by questionnaires that were answered by all patients included in this report. Logistic regressions with generalized estimating equations were performed to evaluate the association of radiographic features of FAI and arthrosis., Results: Pincer, cam, or mixed types of radiographic FAI had a prevalence of 57% (1748 of 3053), 29% (886 of 3053), and 14% (419 of 3053), respectively, in this group of older men. Both pincer and mixed types of FAI were associated with arthrosis but not with hip pain (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.25-2.13; p<0.001 for pincer and OR, 2.49; 95% CI, 1.65-3.76; p<0.001 for mixed type). Patients with hips characterized by cam-type FAI had slightly reduced hip pain without the presence of arthrosis compared with hips without FAI (OR, 0.82; 95% CI, 0.68-0.99; p=0.037). A center-edge angle>39° and a caput-collum-diaphyseal angle<125° were associated with arthrosis (OR, 1.53; 95% CI, 1.22-1.94; p<0.001 and OR, 2.09; 95% CI, 1.24-3.51; p=0.006, respectively), but not with hip pain (OR, 0.89; 95% CI, 0.77-1.03; p<0.108 and OR, 0.99; 95% CI, 0.67-1.45; p=0.945, respectively). An impingement angle<70° was associated with less hip pain compared with hips with an impingement angle≥70° (OR, 0.76; 95% CI, 0.61-0.95; p=0.015)., Conclusions: FAI is common in older men and represents more of an anatomic variant rather than a symptomatic disease. This finding should raise questions on how age, activities, and this anatomic variant each contribute to result in symptomatic disease., Level of Evidence: Level III, prognostic study.

Different disorders around the hip joint have been diagnosed in athletes of all levels. Pathologies such as femoro-acetabular impingement (FAI) are responsible for lower performance during sports and early onset osteoarthrosis of the hip joint. This article emphasizes on the diagnosis and early treatment of FAI in young athletes. It is meant to raise concern about this relatively new pathology and hence avoid the deleterious results for the hip joint associated with late diagnosis.

Purpose: To evaluate a short, hip-oriented outcome instrument, based on the Core Outcome Measures Index (COMI), in patients undergoing surgery for femoroacetabular impingement (FAI)., Methods: The following full-length questionnaires were completed preoperatively and at 6 and 12 months postoperatively by 159 consecutive FAI patients: Hip Outcome Score (HOS); Oxford Hip Score; Western Ontario and McMaster Universities Arthritis Index; Short Form 12 Health Survey; World Health Organization Quality of Life questionnaire, short version; and EuroQol-Five Dimensional index. The scores for the 6 hip-oriented Core Outcome Measures Index (COMI-Hip) items-addressing pain, function, symptom-specific well-being, quality of life, and disability-were extracted from established full-length questionnaires, and their performance as an index was compared with that of the full-length instruments., Results: Scores for the single items of the COMI-Hip questionnaire correlated well with the scores for the corresponding full-length instruments from which they were extracted (r = -0.89 to -0.62, P < .001). The COMI-Hip sum score also correlated well with the Oxford Hip Score and the Western Ontario and McMaster Universities Arthritis Index pain and function scores (r = -0.85 to -0.70, P < .001), as well as with the HOS (r = -0.72 to -0.60, P < .001), an instrument specifically developed for assessing FAI patients. Internal responsiveness (Cohen d for effect size) of the COMI-Hip sum score from preoperatively to 12 months postoperatively was similar to that of the HOS activities-of-daily living subscale (d = -0.76 and d = -0.68, respectively; P < .001). Significant correlations were found between the change scores of the COMI-Hip sum score and those of the HOS activities-of-daily living and sport subscales at 6 months (r = -0.62 and r = -0.60, respectively; P < .001) and 12 months (r = -0.69 and r = -0.61, respectively; P < .001), showing the external responsiveness of the COMI-Hip., Conclusions: The COMI-Hip is a simple yet valid and responsive outcome instrument for the efficient assessment of patients undergoing surgery for FAI. It performs at least as well as the current reference instrument for FAI, the HOS, and can therefore be considered a potentially valuable instrument for routine use in both research and clinical practice., Level of Evidence: Level II, development of diagnostic criteria based on consecutive patients (with universally applied reference gold standard)., (Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Chronic hip and groin pain offers a diagnostic challenge for the sports medicine practitioner. Recent consensus suggests diagnostic categorization based on 5 clinical entities: hip joint-, adductor-, pubic bone stress injury-, iliopsoas-, or abdominal wall-related pathology. However, their prevalence patterns and coexistence in an active population are unclear., Purpose: This study presents a descriptive epidemiology based on a large sample of active individuals with long-standing pain in the hip and groin region. The objectives were to examine the prevalence of key clinical entities, document coexisting pathologies, and present prevalence patterns based on key demographics., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A retrospective review was conducted of clinical records of all hip and groin injuries seen between January 2006 and December 2011 under the care of a single experienced sports medicine consultant. In all cases, imaging was undertaken by a team of specialist musculoskeletal radiologists. Diagnoses were categorized according to 5 clinical entities using contemporary diagnostic nomenclature. The chi-square test was used to compare observed and expected frequencies across each subgroup's prevalence figures based on sex, age, and sports participation., Results: Full medical records were retrieved from 894 patients with chronic hip and groin pain. The majority of patients were male (73%), aged between 26 and 30 years, and participating in footballing codes (soccer, rugby, and Gaelic sports) or running. A total of 24 combinations of clinical entities were found. There were significant differences (P < .001) in prevalence patterns based on age, sex, and sports activity. Adductor-related pain or pubic bone stress injury rarely presented in isolation. Hip joint pathology was the most common clinical entity (55.98%) and was significantly more likely to present in isolation. The majority of hip joint pathologies related to femoroacetabular impingement (40%), labral tears (33%), and osteoarthritis (24%). These figures were significantly different across male and female patients (P < .001), with a higher percentage of cases of femoroacetabular impingement and labral tears in male and female patients, respectively., Conclusion: Chronic hip and groin pain is often associated with multiple clinical entities. Hip joint pathology is the most common clinical entity and is most likely to relate to femoroacetabular impingement, labral tears, and osteoarthritis. These pathologies seem to be associated with secondary breakdown of surrounding structures; however, underpinning mechanisms are unclear., (© 2015 The Author(s).)

Background: Surgery for hip femoroacetabular impingement/acetabular labral tear (FAI/ALT) is exponentially increasing despite lacking investigation of the accuracy of various diagnostic measures. Useful clinical utility of these measures is necessary to support diagnostic imaging and subsequent surgical decision-making., Objective: Summarise/evaluate the current diagnostic accuracy of various clinical tests germane to hip FAI/ALT pathology., Methods: A computer-assisted literature search of MEDLINE, CINAHL and EMBASE databases using keywords related to diagnostic accuracy of the hip joint, as well as the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for the search and reporting phases of the study. Quality assessment of bias and applicability was conducted using the Quality of Diagnostic Accuracy Studies-2 (QUADAS-2). Random effects models were used to summarise sensitivities (SN), specificities (SP), diagnostic odds ratio (DOR) and respective confidence intervals (CI)., Results: The employed search strategy revealed 21 potential articles, with one demonstrating high quality. Nine articles qualified for meta-analysis. The meta-analysis demonstrated that flexion-adduction-internal rotation (pooled SN ranging from 0.94 (95% CI 0.90 to 0.97) to 0.99 (95% CI 0.98 to 1.00); DOR 5.71 (95% CI 0.84 to 38.86) to 7.82 (95% CI 1.06 to 57.84)) and flexion-internal rotation (pooled SN 0.96 (95% CI 0.81 to 0.99); DOR 8.36 (95% CI 0.41 to 171.3) tests possess only screening accuracy., Conclusions: Few hip physical examination tests for diagnosing FAI/ALT have been investigated in enough studies of substantial quality to direct clinical decision-making. Further high-quality studies across a wider spectrum of hip pathology patients are recommended to discern the confirmed clinical utility of these tests., Trials Registration Number: PROSPERO Registration # CRD42014010144., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background: Prior literature has suggested an association between the radiographic signs of femoroacetabular impingement (FAI) and femoral neck stress fractures (FNSF) or femoral neck stress reactions (FNSR). At the time of the writing of this article, no study has described the association of FAI and FNSF/FNSR along with the need for surgical intervention and outcomes., Objective: To determine the prevalence of radiographic features of FAI in patients diagnosed with FNSF., Design: Retrospective case series., Setting: Tertiary care, institutional setting., Patients: A medical records search program (Stanford Translational Research Integrated Database Environment, Stanford University, California) was used to retrospectively search for patients 18-40 years old with a history of FNSF or FNSR. The records were obtained from the period July 25, 2003, to September 23, 2011., Methods: For assessment of risk factors, plain radiographs and magnetic resonance imaging studies were reviewed for features of cam or pincer FAI. Medical records were reviewed to determine whether patients required operative intervention., Main Outcome Measures: Incidence of abnormal alpha (α) angle, abnormal anterior offset ratio, abnormal femoral head-neck junction, coxa profunda, positive crossover sign, and abnormal lateral center-to-edge angle., Results: Twenty-one female and 3 male participants (mean age 27 years, range 19-39 years) were identified with magnetic resonance imaging evidence of femoral neck stress injury. Cam morphology was seen in 10 patients (42%). Pincer morphology could be assessed in 18 patients, with coxa profunda in 14 (78%) and acetabular retroversion in 6 (14%). Features of combined pincer and cam impingement were observed in 4 patients (17%). Seven patients (29%) had operative intervention, with 3 (12%) requiring internal fixation of their femoral neck fractures, and all had radiographic evidence of fracture union after surgery. Four patients (17%) had persistent symptoms after healing of their FNSF with conservative treatment and eventually required surgery for FAI, 3 had no pain at final follow-up 1 year post-surgery, and one patient was lost to follow-up., Conclusion: The results of the current study suggest that patients in the general population with femoral neck stress injuries have a higher incidence of bony abnormalities associated with pincer impingement, including coxa profunda and acetabular retroversion, although it is unclear whether pincer FAI is a true risk factor in the development of FNSF., (Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

We present a novel method for quantifying femoral orientation angles using a thigh-mounted inertial measurement unit (IMU). The IMU-derived femoral orientation angles reproduce gold-standard motion capture angles to within mean (standard deviation) differences of 0.1 (1.1) degrees on cadaveric specimens during clinical procedures used for the diagnosis of Femoroacetabular Impingement (FAI). The method, which assumes a stationary pelvis, is easy to use, inexpensive, and provides femur motion trajectory data in addition to range of motion measures. These advantages may accelerate the adoption of this technology to inform FAI diagnoses and assess treatment efficacy. To this end, we further investigate the accuracy of hip joint angles calculated using this methodology and assess the sensitivity of our estimates to skin motion artifact during these tasks.

Introduction: Femoroacetabular impingement (FAI) is a recognised cause of secondary osteoarthritis of the hip. Several imaging methods have been used to analyse the pathologic signs. Because of the lack of precise pre- and intraoperative overview and the difficulty locating osseous pathologies, arthroscopic and minimal invasive treatment is still challenging, even for trained surgeons. This paper describes a procedure that is based on magnetic resonance arthrography (MRA) and is used to virtually verify the range of motion (ROM) of the hip. It enables the evaluation of FAI and the preoperative simulation of adequate surgical manoeuvres., Methods: Each MRI was completed on a 3.0 T system using a flexible transmit/receive surface body coil with the patient in the supine position. An axial three-dimensional (3D) gradient-echo (VIBE, volume interpolated breathhold examination) sequence was performed. For the generation of 3D bone models, semiautomatic segmentation of the MRA data was accomplished using Amira(®) visualisation software version 5.2. The self-developed software "HipProject", written in C++, computes the maximal ROM of the hip. The virtual colliding regions were visualised for verification and simulation of osseous trimming., Results: In addition, for necessary information about damage to the cartilage and labrum, "black bone" MRA was used to generate extremely precise 3D reconstructions of the hip joint to automatically calculate the preoperative osseous ROM. Furthermore, the acetabular and femoral locations of the impingement zone were individually visualised and quantified., Conclusions: The described procedure is a useful tool for the preoperative investigation of impinging hips. It enables appropriate planning of required surgical interventions.

The objective of this article was to emphasize the importance of including less common causes of hip pain in a differential diagnosis, particularly when clinical and radiographic variables are atypical. This article presents the case of a 52-year-old patient with a history of progressive hip pain resulting from the coexistence of both a femoroacetabular impingement (FAI) and an intraarticular osteoid osteoma. The intraarticular osteoid osteoma was initially overlooked due to its unremarkable features on radiographic and resonance imaging. Consequently, the patient was surgically treated for FAI with only partial relief. An osteolytic nidus characteristic of osteoid osteoma was discovered only 1.5 years following surgery. The patient was subsequently treated for osteoid osteoma with anti-inflammatories, after which his pain began to resolve. The patient was completely pain free after 7 months. Level of evidence V.

Femoroacetabular impingement (FAI), a recently described hip condition in adolescents and young adults, typically manifests as activity-related hip pain. Characteristic physical findings include limited passive internal rotation of the affected hip and a positive impingement sign. Diagnostic imaging may reveal cam and/or pincer lesions, and associated intra-articular pathology (eg, labral tear, chondral damage) is common. When nonoperative treatment fails to adequately alleviate symptoms, surgery may be warranted. Both open and arthroscopic techniques have been effective. As our understanding of FAI continues to evolve, sex-based differences in incidence, presentation, and outcomes for patients with FAI have become apparent. Understanding the different ways in which males and females may present with FAI and then changing clinical practice patterns to accommodate these sexual dimorphisms will likely result in improved outcomes for each patient with symptomatic FAI.

Background: Femoroacetabular impingement is a recognized cause of chondrolabral injury. Although surgical treatment for impingement seeks to improve range of motion, there are very little normative data on dynamic impingement-free hip range of motion (ROM) in asymptomatic people. Hip ultrasound demonstrates labral anatomy and femoral morphology and, when used dynamically, can assist in measuring range of motion., Questions/purposes: The purposes of this study were (1) to measure impingement-free hip ROM until labral deflection is observed; and (2) to measure the maximum degree of sagittal plane hip flexion when further flexion is limited by structural femoroacetabular abutment., Methods: Forty asymptomatic adult male volunteers (80 hips) between the ages of 21 and 35 years underwent bilateral static and dynamic hip ultrasound examination. Femoral morphology was characterized and midsagittal flexion passive ROM was measured at two points: (1) at the initiation of labral deformation; and (2) at maximum flexion when the femur impinged on the acetabular rim. The mean age of the subjects was 28 ± 3 years and the mean body mass index was 25 ± 4 kg/m(2)., Results: Mean impingement-free hip passive flexion measured from full extension to initial labral deflection was 68° ± 17° (95% confidence interval [CI], 65-72). Mean maximum midsagittal passive flexion, measured at the time of bony impingement, was 96° ± 6° (95% CI, 95-98)., Conclusions: Using dynamic ultrasound, we found that passive ROM in the asymptomatic hip was much less than the motion reported in previous studies. Measuring ROM using ultrasound is more accurate because it allows anatomic confirmation of terminal hip motion., Clinical Significance: Surgical procedures used to treat femoroacetabular impingement are designed to restore or increase hip ROM and their results should be evaluated in light of precise normative data. This study suggests that normal passive impingement-free femoroacetabular flexion in the young adult male is approximately 95°.

Educational Objectives: As a result of reading this article, physicians should be able to: 1. Identify the etiology of femoroacetabular impingement. 2. Assess femoroacetabular impingement on physical examination. 3. Recognize femoroacetabular impingement on imaging studies. 4. Discuss modern techniques to effectively treat femoroacetabular impingement, both open and arthroscopic. Femoroacetabular impingement (FAI) is a recently proposed concept describing abnormal anatomic relationships within the hip joint that may lead to articular damage. Impingement is caused by bony deformities or spatial malorientation of the femoral head-neck junction and/or the acetabulum. These abnormalities lead to pathologic contact and shearing forces at the acetabular labrum and cartilage during physiological hip motion. There is an increasing body of evidence that these forces lead to cartilage wear and eventual osteoarthritis. Treatment options for FAI are evolving rapidly. Although the gold standard remains open hip dislocation, arthroscopic techniques have shown significant promise. It is possible that early recognition and treatment of subtle deformity about the hip may reduce the rate of hip osteoarthritis in the future., (Copyright 2015, SLACK Incorporated.)

Background: A lateral radiograph of the proximal femur is critical in the evaluation of patients with suspected femoroacetabular impingement. Positioning patients for a cross-table lateral (XTL) image is difficult, which may result in repeat exposures and increased cumulative radiation. Alternatively, the 45-degree Dunn (Dunn) and single frog lateral (SFL) views have been shown to accurately reveal proximal femoral abnormalities in femoroacetabular impingement. The purpose of this study was to compare the effective radiation doses (ERD) for 3 lateral hip projections that provide similar diagnostic information., Methods: Patients presenting to the adolescent hip clinic with indicated examinations were evaluated with a standard anteroposterior (AP) pelvic radiograph and one of 3 lateral hip radiographs: XTL (n=16), Dunn (n=17), or SFL (n=27). Technical exposure parameters and published reference data for an AP pelvic radiograph were used to extrapolate the ERD. A simple Pearson r correlation test determined the relationships between body mass index, age, and ERD. The rate of repeat exposures per study was calculated., Results: Body mass index positively correlated (r=0.34) and age and negatively correlated (r=-0.27) with ERD. ERD was increased for the XTL (0.83±0.98 mSv) over the Dunn (0.37±0.15 mSv) and SFL (0.22±0.11 mSv; P<0.05). Repeat exposures were performed in 10.4%, 4%, and 6% of XTL, Dunn, and SFL studies, respectively., Conclusions: The ERD for a single projection is highest for the XTL, and the examination is more likely to be repeated. The XTL radiograph should be avoided whenever possible and substituted with alternative images providing similar diagnostic information, such as the Dunn or SFL, to minimize lifetime cumulative radiation exposure to the patient., Level of Evidence: Level II.

Purpose: The aim of this study was to assess the outcome of hip preserving surgery for femoroacetabular impingement relative to the condition resulting in FAI and to the patient's age at the time of the surgery., Methods: With the conditions for exclusion duly met, enrolled in our study were a total of 100 hip joints (83 operated on with the aid of SHD, 17 with AMIS). The minimum follow-up period was 12 months, and the mean follow-up time was three years four months. WOMAC and NAHS questionnaires were used as rating instruments. To analyse the significance of the differences relative to the age at the time of surgery and to the basic diagnosis leading to FAI and subsequently to surgical operation we used non-parametric forms of analysis of variance (Friedman test and Kruskal-Wallis test), i.e., comparisons of the patients' pre-operative and postoperative states, estimation of the rate of improvement in the postoperative functional skills in relation to the age at the time of surgery and/or relative to the basic diagnosis necessitating surgical intervention, with respect to statistical significance at the level of p < 0.05., Results: As testing of our cohort of patients and results analysis showed, the youngest group (<30 years) compared with the rest of the cohort shows greater postoperative improvement and consequently also a better surgical result. Proof was also obtained that the diagnosis leading to surgery for FAI has no effect on the patient's pre- or postoperative state or on the degree of improvement., Conclusions: The results of the study affirm the relevance of hip preserving surgery, especially in younger-aged groups.

The concept of femoroacetabular impingement (FAI) has, in a relatively short time, come to the forefront of orthopedic imaging. In just a few short years MRI findings that were in the past ascribed to degenerative change, normal variation, or other pathologies must now be described and included in radiology reports, as they have been shown, or are suspected to be related to, FAI. Crucial questions have come up in this time, including: what is the relationship of bony morphology to subsequent cartilage and labral damage, and most importantly, how is this morphology related to the development of osteoarthritis? In this review, we attempt to place a historical perspective on the controversy, provide guidelines for interpretation of MRI examinations of patients with suspected FAI, and offer a glimpse into the future of MRI of this complex condition., (© 2014 Wiley Periodicals, Inc.)

Background: In the clinical evaluation of femoroacetabular impingement (FAI), there is a lack of quantitative, reliable and informative assessment methods for the overall functional capability of an individual., Objective: We compared clinical and radiological measurements of the hip joint with a new methodology based on the concept of 3-dimensional reachable workspace using Microsoft Kinect., Methods: We assessed the correlation between the alpha angle of Nötzli on full-length radiographs and the clinical internal rotation. We evaluated the accuracy of joint positions and angles of the hip between the Kinect system and clinical examination including range of motion (ROM)., Results: The results of our clinical trial with 24 study participants showed a significant difference between normal internal rotation (> 21°) and reduced internal rotation (⩽ 21°) in comparison to the radiological alpha angle of Nötzli (P=0.026). The acquired reachable Kinect data demonstrated a moderate agreement between the Kinect and clinical examination (correlation coefficients between 0.230 and 0.375)., Conclusions: The findings suggest that a higher grade alpha angle of Nötzli accompanies reduced clinical internal rotation. The Kinect system provides reliable results of hip ROM. However, further test series must be performed for the application of Kinect in the clinical evaluation of FAI.

Although femoroacetabular impingement (FAI) syndrome is included in the etiology of lesions involving the acetabular labrum and acetabular cartilage, it is one of many possible reasons behind osteochondral lesions in the femoral head. Herein, we present clinical findings and outcomes of two cases with osteochondral defects and cam type impingement of femoral head. Both cases underwent autologous osteochondral mosaicplasty along with femoral osteochondroplasty following controlled hip dislocation. Harris hip scores improved significantly postoperatively and magnetic resonance imaging showed an adequate graft union and formation of a healthy chondral surface at the final assessment. Autologous osteochondral mosaicplasty of parafoveal region defects and femoral neck osteochondroplasty combination may be an effective treatment method for young patients with FAI syndrome. In addition, we believe that cam type impingement may also have a role in the etiology of parafoveal osteochondral lesions.

Orthopaedic surgeons frequently treat patients who report pain that radiates from the back into the lower extremity. Although the most common etiology is either a herniated disk or spinal stenosis, a myriad of pathologies can mimic the symptoms of radiculopathy, resulting in differences in the clinical presentation and the workup. Therefore, the clinician must be able to distinguish the signs and symptoms of lumbar radiculopathy from pathologies that may have a similar presentation. Being cognizant of these other possible conditions enables the physician to consider a breadth of alternative diagnoses when a patient presents with radiating lower extremity pain., (Copyright 2014 by the American Academy of Orthopaedic Surgeons.)

Femoroacetabular impingement is the mechanical contact between the femur and the pelvis, frequently between the femur neck and the acetabular rim, whether due to a deformity of the former (cam type) or the latter (pincer type). However, there may be extraarticular causes of impingement. Together with the increased diagnosis of impingement, arthroscopic treatment is increasingly frequent and has become the standard treatment. This report analyzes a case of extraarticular hip impingement caused by contact between the femur and a prominent anteroinferior iliac spine (AIIS), probably due to a healed old avulsion and its later arthroscopic management.