The gymnasts' hip and groin: a magnetic resonance imaging study in asymptomatic elite athletes

Lost in research translation: Female athletes are not male athletes, especially at the hip

Altered shape of the proximal femur (cam morphology) or acetabulum (pincer morphology) is indicative of femoroacetabular impingement, which can result in hip pain and osteoarthritis of the hip. As mechanical load during growth affects the resulting bone shape, there is strong evidence in males that cam morphology develops during skeletal growth while physes are open, rather than as an adaptation after growth plates are closed (skeletal maturity). This adaptation is particularly evident in athletes who participate at elite levels prior to skeletal maturity. The research providing this evidence, however, has primarily focused on male athletes. Despite the lack of inclusion in the research, females consistently comprise two thirds of the clinical and surgical populations with structural hip pain or pathology. Knowledge gained from male-dominated cohorts may not appropriately transfer to female athletes, especially at the hip. This perspectives article briefly reviews differences between females and males in femoral and acetabular structure, hormones, timing of puberty/maturation, hypermobility, activity level and movement control-factors which affect hip structure development and loading. Without female-focused research, the application of research findings from male athletes to female athletes may lead to ineffective or even inappropriate recommendations and treatments. Thus, there is a critical need for investment in research to promote life-long hip health for females.

Preseason lower extremity range of motion, flexibility, and strength in relation to in-season injuries in NCAA division I gymnasts

OBJECTIVES

To determine if preseason lower extremity ROM, flexibility, and strength differ in collegiate gymnasts (NCAA Division 1) who do or do not sustain an injury during the competitive season.

METHODS

Over four seasons, a total of 15 female gymnasts (age = 20.5 ± 1.0 years) underwent preseason screening (30 gymnast-season). We tested joint ROM (hip: flexion, internal and external rotation; ankle: weightbearing dorsiflexion), muscle flexibility (passive straight leg raise, Thomas,' Ober's, Ely's tests) and strength (hip extensors, abductors, and flexors isometric strength via a handheld dynamometer; knee: quadriceps and hamstring isokinetic strength at 60°/sec). The team athletic trainer tracked overuse lower extremity injuries (restricted gymnasts from full participation, occurred as from participation in organized practice or competition, and required medical attention) during each season. For athletes that tested multiple seasons, each encounter was considered independent, and each preseason assessment was linked to overuse injuries sustained during the same competitive season. Gymnasts were dichotomized into injured and non-injured groups. An independent t-test was used to measure differences in preseason outcomes between injured and non-injured groups.

RESULTS

During four years, we recorded 23 overuse lower extremity injuries. Gymnasts that sustained an in-season overuse injury demonstrated significantly lower hip flexion ROM (mean difference: -10.6°; 95% confidence interval: -16.5, -4.6; p < 0.01) and lower hip abduction strength (mean difference: -4.7% of body weight; 95% confidence interval: -9.2, -0.3; p = 0.04).

CONCLUSION

Gymnasts who sustain an in-season overuse lower extremity injury have significant preseason deficit of hip flexion ROM and weakness in the hip abductors. These findings indicate potential impairments in the kinematic & kinetic chains responsible for skill performance and energy absorption during landing.

Does the ultrasound imaging predict lower limb tendinopathy in athletes: a systematic review

BACKGROUND

To conduct a systematic review looking into the possibility of US imaging to anticipate and identify future patellar or Achilles tendinopathy symptoms.

METHODS

The studies that were taken into consideration for this review were prospective studies that employed baseline US imaging of the patellar OR Achilles tendons in asymptomatic patients and follow-up measures of pain and/or function. Two impartial reviewers evaluated the study's quality using the Critical Appraisal Skills Programme instrument.

RESULTS

Participants in the included studies in this review came from various sports. The systematic review revealed a link between baseline tendon abnormalities in the US and a higher chance of developing both patellar and Achilles tendinopathy as well as their future occurrence. Nine of the included studies examined the patellar tendon alone, eight the patellar and Achilles tendon together, and four the Achilles tendon exclusively. For both tendons, US administration is done in a largely consistent manner. The tendon abnormalities of tendon thickness, hypoechogenicity and vascularity at baseline were associated with an increased risk of both Achilles and patellar tendinopathy.

CONCLUSIONS

This systematic review shows that abnormal tendon structures seen by US in asymptomatic persons can predict the development of tendinopathy.

Effect of hip dysplasia on the development of the femoral head growth plate

Purpose

The purpose of this study was to observe whether developmental dysplasia of the hip (DDH) affects the development of the femoral head growth plate and to analyze the risk factors.

Methods

We selected female patients aged between 11 and 20 years with unilateral DDH and unclosed femoral head growth plate (s). The selected patients underwent anteroposterior radiography of the hip joint to compare the degree of development of the femoral head growth plate on both sides and to identify risk factors that affect the development of the growth plate in the femoral head.

Results

We included 48 female patients with unilateral DDH, with an average age of 14 years (range: 11.1-18.5 years) and an average BMI of 20.4 kg/m² (range: 15.5 kg/m²-27.9 kg/m²). Among them, 23 patients had earlier development of the femoral head growth plate on the affected side than on the healthy side, while the degree of development of the femoral head growth plate in 25 patients was the same as that on the contralateral side. When the Tönnis angle was greater than 29.5°C and/or the Reimers migration index was greater than 48.5%, there was a statistically significant difference in the acceleration of femoral head growth plate development.

Conclusion

An abnormal relative position of the acetabulum-femoral head caused by DDH can accelerate closure of the femoral head growth plate in immature female patients. The risk factors are a Tönnis angle greater than 29.5°C and/or Reimers migration index greater than 48.5%.

Associations between long-term exercise participation and lower limb joint and whole-bone geometry in young and older adults

Introduction: Features of lower limb bone geometry are associated with movement kinematics and clinical outcomes including fractures and osteoarthritis. Therefore, it is important to identify their determinants. Lower limb geometry changes dramatically during development, partly due to adaptation to the forces experienced during physical activity. However, the effects of adulthood physical activity on lower limb geometry, and subsequent associations with muscle function are relatively unexplored. Methods: 43 adult males were recruited; 10 young (20-35 years) trained i.e., regional to world-class athletes, 12 young sedentary, 10 older (60-75 years) trained and 11 older sedentary. Skeletal hip and lower limb geometry including acetabular coverage and version angle, total and regional femoral torsion, femoral and tibial lateral and frontal bowing, and frontal plane lower limb alignment were assessed using magnetic resonance imaging. Muscle function was assessed recording peak power and force of jumping and hopping using mechanography. Associations between age, training status and geometry were assessed using multiple linear regression, whilst associations between geometry and muscle function were assessed by linear mixed effects models with adjustment for age and training. Results: Trained individuals had 2° (95% CI:0.6°-3.8°; p = 0.009) higher femoral frontal bowing and older individuals had 2.2° (95% CI:0.8°-3.7°; p = 0.005) greater lateral bowing. An age-by-training interaction indicated 4° (95% CI:1.4°-7.1°; p = 0.005) greater acetabular version angle in younger trained individuals only. Lower limb geometry was not associated with muscle function (p > 0.05). Discussion: The ability to alter skeletal geometry via exercise in adulthood appears limited, especially in epiphyseal regions. Furthermore, lower limb geometry does not appear to be associated with muscle function.

Quadratus femoris muscle edema in children

OBJECTIVE

To assess the prevalence and clinical relevance of quadratus femoris muscle edema (QFME) in pediatric pelvic MRI.

MATERIALS AND METHODS

The axial T2-W with fat saturation sequence of pelvic/hip MRI examinations of pediatric patients (≤ 18 years) and a control group of young adults aged 19-45 years was retrospectively and independently evaluated by two musculoskeletal radiologists for the presence of QFME in each hip. Demographics, indication for imaging studies, and pain location were documented. The prevalence of QFME was compared between the groups on a patient level and on a hip level.

RESULTS

The study group included 119 children (164 MRI examinations; F:M 1:1.08, mean age 11.4 ± 3.6 years), and 120 young adults, > 18, < 45 years old, served as controls (F:M 1:0.9, mean age 33.7 ± 6.4 years). QFME was significantly more prevalent among the study compared to the control group, both on a patient level (15% and 4.2%, respectively, p < 0.05) and on a hip level (12.1% and 2.5%, respectively, p < 0.05). This significant difference was also seen in the subgroup of MRI studies performed for orthopedic indications but not for non-orthopedic indications. There was no correlation between the side of localized pain and the side with QFME.

CONCLUSION

QFME is significantly more prevalent in pediatric patients compared to adults under 45 years old, especially in subjects scanned for orthopedic indications. The clinical relevance of QFME in children and adolescents is unclear.

Imaging of Anatomical Variants Around the Hip

Considering the current widespread use of imaging as an integral part of managing hip pain, variable hip geometries and anatomical variants are increasingly being detected. These variants are commonly found in the acetabulum and proximal femur, as well as the surrounding capsule-labral tissues. The morphology of specific anatomical spaces confined by the proximal femur and the bony pelvis may also vary significantly among individuals. Familiarity with the spectrum of imaging appearances of the hip is necessary to identify variant hip morphologies with or without potential clinical relevance and reduce an unnecessary work-up and overdiagnosis. We describe anatomical variations and variable morphologies of the bony structures comprising the hip joint and the soft tissues, around the hip. The potential clinical significance of these findings is further analyzed in conjunction with the patient's profile.

Criteria for the Operating Room Confirmation of the Diagnosis of Hip Instability: The Results of an International Expert Consensus Conference

PURPOSE

The purpose of this study was to establish an international expert consensus on operating room findings that aid in the diagnosis of hip instability.

METHODS

An expert panel was convened to build an international consensus on the operating room diagnosis/confirmation of hip instability. Seventeen surgeons who have published or lectured nationally or internationally on the topic of hip instability were invited to participate. Fifteen panel members completed a pre-meeting questionnaire and agreed to participate in a 1-day consensus meeting on May 15, 2021. A review of the literature was performed to identify published intraoperative reference criteria used in the diagnosis of hip instability. Studies were included for discussion if they reported and intraoperative findings associated with hip instability. The evidence for and against each criteria was discussed, followed by an anonymous voting process. For consensus, defined a priori, items were included in the final criteria set if at least 80% of experts agreed.

RESULTS

A review of the published literature identified 11 operating room criteria that have been used to facilitate the diagnosis of hip instability. Six additional criteria were proposed by panel members as part of the pre-meeting questionnaire. Consensus agreement was achieved for 8 criteria, namely ease of hip distraction under anesthesia (100.0% agreement), inside-out pattern of chondral damage (100.0% agreement), location of chondral damage on the acetabulum (93.3% agreement), pattern of labral damage (93.3% agreement), anteroinferior labrum chondral damage (86.7% agreement), perifoveal cartilage damage (97.6% agreement), a capsular defect (86.7% agreement), and capsular status (80.0% agreement). Consensus was not achieved for 9 items, namely ligamentum teres tear (66.7% agreement), arthroscopic stability tests (46.7% agreement), persistent distraction after removal of traction (46.7% agreement), findings of examination under anesthesia (46.7% agreement), the femoral head divot sign (40.0% agreement), inferomedial synovitis (26.7% agreement), drive-through sign (26.7% agreement), iliopsoas irritation (26.7% agreement) and ligamentum teres-labral kissing lesion (13.3% agreement). All experts agreed on the final list of 8 criteria items reaching consensus.

CONCLUSION

This expert panel identified 8 criteria that can be used in the operating room to help confirm the diagnosis of hip instability.

LEVEL OF EVIDENCE

Level V expert opinion.

Pathologic Findings on Hip Arthroscopy in High-Level Athletes Competing in Flexibility Sports

BACKGROUND

Athletes who compete in flexibility sports (FS) place unique demands on their hip joints because of the supraphysiologic range of motion required.

PURPOSE

To compare the pathologic features, outcomes, and return-to-sports (RTS) rates of high-level athletes participating in FS who underwent hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and labral tear against a propensity score-matched cohort of high-level athletes participating in non-flexibility sports (NFS).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data were prospectively collected and retrospectively reviewed for high-level athletes who underwent primary hip arthroscopy for FAIS from April 2008 to December 2018. Patients who participated in FS such as dancing, gymnastics, martial arts, figure skating, and cheerleading were propensity score matched by body mass index, age at time of surgery, sex, sports competition level, and labral treatment to a cohort of high-level athletes participating in all other sports, such as distance running, soccer, volleyball, and softball. Baseline patient characteristics, intraoperative findings, and surgical procedures were compared. Minimum 2-year patient-reported outcome measures were compared for the modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sport Specific Subscale, and visual analog scale for pain and satisfaction. Rates of secondary surgery and RTS were compared.

RESULTS

A total of 47 patients (50 hips) who participated in FS were included and propensity score matched to 130 patients (150 hips) who participated in NFS. Follow-up time was 37.5 ± 10.4 months (mean ± SD). Most patients (96.0%) were female with a mean age of 19.5 ± 7.3 years. FS athletes had significantly higher rates of femoral head cartilage lesions (Outerbridge ≥2; 12.0% vs 2.0%; P = .008) and ligamentum teres tears (48% vs 26%; P = .003). FS and NFS athletes demonstrated significant clinical improvements after surgery for all patient-reported outcome measures. Of the patients who attempted, 34 (75.6%) participating in FS were able to RTS while 11 (24.4%) were not because of ongoing hip issues. This was not significantly different than the NFS group (P = .073).

CONCLUSION

High-level athletes who participated in FS and were treated for FAIS with hip arthroscopy exhibited higher rates of femoral head cartilage lesions and ligamentum teres tears requiring debridement when compared with a benchmark group of athletes who participated in other sports. Despite this, both groups demonstrated similar improvements in outcome scores and comparable rates of RTS at minimum 2-year follow-up.

Indications and Outcomes After Ligamentum Teres Reconstruction: A Systematic Review

Purpose

To systematically review the literature to better understand the current indications for ligamentum teres reconstruction (LTR), current graft and acetabular fixation options used, patient-reported outcomes after LTR, and incidence of complications and reoperations after LTR.

Methods

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. All literature related to LTR published prior to July 2020 was identified. The inclusion criteria consisted of investigations reporting on human patients with pathology of the ligamentum teres who underwent LTR, including mentions of the indications, graft type, acetabular fixation method, postoperative patient-reported outcome scores, and incidence of complications and reoperations.

Results

Seven studies comprising 26 patients (28 hips) were included. The most commonly reported indication for LTR was persistent pain and instability after failed prior hip arthroscopy (68%, 19 of 28 hips). The mean postoperative modified Harris Hip Score, Non-arthritic Hip Score, and visual analog scale score all showed improvement when compared with preoperative values. A total of 2 complications occurred. Complication rates ranged from 0% to 100% in included case reports and 0% to 11% in included case series. A total of 9 reoperations were performed. Reoperation rates ranged from 0% to 100% for case reports and 18% to 100% for case series. Reoperation rates ranged from 33% to 100% in studies with patients receiving acetabular fixation using anchors versus 0% to 22% in studies performing LTR with buttons. Reoperation rates in athletic patients and patients with Ehlers-Danlos syndrome ranged from 0% to 100% and 0% to 50%, respectively.

Conclusions

The main indication for LTR was persistent hip or groin pain and instability after a prior hip arthroscopy. The short-term postoperative modified Harris Hip Score, Non-arthritic Hip Score, and visual analog scale score after LTR showed favorable outcomes. However, reoperations after LTR were not uncommon.

Level of Evidence

Level V, systematic review of Level IV and V studies.

Microinstability of the hip: a systematic review of the imaging findings

OBJECTIVES

To undertake a systematic review of the morphologic features associated with hip microinstability and determine whether there are suggestive or diagnostic imaging findings.

METHODS

Four electronic databases were searched up to September 2019 to identify original research reporting morphologic features in individuals with either a clinical diagnosis of hip microinstability (instability without overt subluxation/dislocation) or those with symptomatic laxity demonstrated on imaging (increased femoral head translation/distraction or capsular volume). Studies focussing on individuals with pre-existing hip conditions (including definite dysplasia (lateral centre edge angle < 20°), significant trauma, previous dislocation or surgery were excluded. Methodological quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

RESULTS

Twenty-two studies met inclusion criteria (clinical diagnosis of microinstability n = 15 and demonstration of laxity n = 7). Imaging information gathered from the studies includes radiographs (n = 14), MRI (n = 6), MR arthrography (n = 4), CT (n = 1) and intraoperative examination. Most studies exhibited design features associated with an overall high or unclear risk of bias. Some dysplastic features are associated with microinstability or laxity reference measures; however, microinstability is frequently diagnosed in those with a lateral centre edge angle > 25°. Other associated imaging findings reported include impingement morphology, anterior labral tearing, femoral head chondral injury, ligamentum teres tears and capsular attenuation.

CONCLUSIONS

The current literature does not provide strong evidence for imaging features diagnostic of microinstability. In the appropriate clinical context, dysplastic morphology, anterior labral tears and ligamentum teres tears may be suggestive of this condition although further research is needed to confirm this.

PROSPERO REGISTRATION

CRD42019122406.

Femoral osteochondroma responsible for ischiofemoral impingement, bursitis, and secondary lipoma arborescens mimicking malignant transformation

We present the case of a 53-year-old woman with a known history of hereditary multiple exostosis disease referred for further imaging work-up after ultrasound and computed tomography leading to the suspicion of malignant transformation of an osteochondroma (exostosis) located on the posteromedial aspect of the right proximal femur. Imaging examinations suggested an ischiofemoral impingement resulting in a secondary bursitis associated with the development of an internal lipoma arborescens. This rare association explained the complexity of the diagnosis. Magnetic resonance imaging (MRI) played a key role in correctly identifying this benign complication of the osteochondroma and in distinguishing those observations from a secondary exostotic chondrosarcoma. MRI findings were subsequently confirmed at surgery and pathological examination.

CLINICAL RELEVANCE of the LIGAMENTUM TERES: A LITERATURE REVIEW

Background

The ligamentum teres (LT) continues to be a structure of debate and interest. Previously thought of as a vestigial structure, an awareness of LT pathology and its potential importance has increased with the expansion of hip arthroscopy.

Purpose

To provide a comprehensive literature synthesis on the LT and provide clinicians with the most current research regarding the LT and its anatomical features, functional relevance, prevalence of injury, risk factors for injury, clinical presentation, and treatment for pathology.

Methods

A systematic literature search was conducted using Medline/PubMed, CINAHL/EBSCO, and Cochrane/Wiley databases/platforms using the following search terms: ligament, ligament teres, hip, femur, femoral head, round ligament.

Results

This search yielded 1284 articles of which 44 met the inclusion/exclusion criteria and contributed to this manuscript. Information on the LT was summarized into the following areas: anatomy, function, injury prevalence, risk factors, mechanism of injury, duration of symptoms, clinical presentation (symptoms, range of motion, functional limitations, special testing), imaging, and treatment.

Conclusions

The results of this review supported the following: 1) the LT has a function in restraining hip rotation range of motion; 2) the prevalence of LT pathology in any given population may be largely dependent on the severity of bony deformity (either femoroacetabular impingement(FAI) or dyplasia) and activity level; 3) older age and acetabular bony deformity (either FAI or dyplasia) are risk factors for generalized LT pathology; 4) unique signs and symptoms are difficult to identify because LT pathology rarely occurs in isolation and is likely the end-stage consequence of other hip pathology; 5) the presence of LT pathology may negatively affect an individual's ability to function; and 6) surgical debridement is recommend for pain relief of partial LT tears with reconstruction possible for complete LT tears when complaints of instability are noted.

Level of Evidence

3.

A systematic review of injuries in gymnastics

OBJECTIVES

To identify all studies of gymnastics injuries and assess injury rates, types, locations, and causes.

METHODS

Seven electronic and two grey literature databases were searched. Two reviewers independently assessed titles/abstracts, abstracted data, and calculated average rates weighted by study size.

RESULTS

One study (n = 963) of three Olympic games (2008,2012,2016) provided injury rates for females of 86.4/1000gymnasts and males 79.9. For 29 databases one study of males (n = 64) provided a rate of 8.8 injuries/1000hours/AE (AE = athletic-exposure) and three of females varied rates (8.5, 9.4, and 91). Three studies for males (n = 153) provided a weighted average rate of 1.4 injuries/1000hours/training, and for females six studies (n = 476) 1.5 injuries. Four studies of males (n = 286) provided a weighted average of 678 injuries/1000gymnasts per year and eight studies of females (n = 1,764) a rate of 306. Of 19 surveys, eight provided rates for females (n = 1,463) of 596 injuries/gymnast per year and two for males (n = 40) a rate of 1,036. In the Olympics injuries were preponderately lower limb (63%) then trunk (23%) and upper limb (14%); injury type was sprains (35%) followed by tendinopathy/arthritis/impingements (17%), contusions (10%), and fractures (7%). Five database studies provided injury location data for 274 males: averages weighted by study size were upper extremity 42.8%, lower extremity 33.6%, torso/spine 11.8%, and head/neck 4.9% and 12 studies with 843 females provided average rates for lower extremity 51%, upper extremity 30.8%, torso/spine 13% and head/neck 0.8%. Official gymnastics organizations' websites provide no readily available data about injury rates or methods of prevention.

CONCLUSIONS

Studies need to collect comprehensive data for injury rates by training/competitions, gender, age, injury location/type/cause. Studies could assess whether trainers and physiotherapists monitoring gymnasts closely for injury risk would reduce injuries. Studies including randomized controlled trials (RCTs) of interventions in training, videotaping and performance feedback to reduce injury rates would be helpful.

Utility of False Profile View for Screening of Ischiofemoral Impingement

Purpose

Ischiofemoral impingement (IFI)-primarily diagnosed by magnetic resonance imaging (MRI)-is an easily overlooked disease due to its low incidence. The purpose of this study was to evaluate the usefulness of false profile view as a screening test for IFI.

Materials and Methods

Fifty-eight patients diagnosed with IFI between June 2013 and July 2017 were enrolled in this retrospective study. A control group (n=58) with matching propensity scores (age, gender, and body mass index) were also included. Ischiofemoral space (IFS) was measured as the shortest distance between the lateral cortex of the ischium and the medial cortex of lesser trochanter in weight bearing hip anteroposterior (AP) view and false profile view. MRI was used to measure IFS and quadratus femoris space (QFS). The receiver operating characteristics (ROC), area under the ROC curve (AUC) and cutoff point of the IFS were measured by false profile images, and the correlation between the IFS and QFS was analyzed using the MRI scans.

Results

In the false profile view and hip AP view, patients with IFI had significantly decreased IFS (P<0.01). In the false profile view, ROC AUC (0.967) was higher than in the hip AP view (0.841). Cutoff value for differential diagnosis of IFI in the false profile view was 10.3 mm (sensitivity, 88.2%; specificity, 88.4%). IFS correlated with IFS (r=0.744) QFS (0.740) in MRI and IFS (0.621) in hip AP view (P<0.01).

Conclusion

IFS on false profile view can be used as a screening tool for potential IFI.

Narrowing of ischiofemoral and quadratus femoris spaces in pediatric ischiofemoral impingement

OBJECTIVE

To correlate MRI findings of quadratus femoris muscle edema (QFME) with narrowing of the ischiofemoral space (IFS) and quadratus femoris space (QFS) in children, and to identify threshold values reflecting an anatomic architecture that may predispose to ischiofemoral impingement.

MATERIALS AND METHODS

A case-control retrospective MRI review of 49 hips in 27 children (mean, 13 years) with QFME was compared to 49 hips in 27 gender and age-matched controls. Two radiologists independently measured IFS and QFS. Generalized linear mixed-effects models were fit to compare IFS and QFS values between cases and controls, and adjust for correlation in repeated measures from the same subject. Receiver operating characteristic (ROC) analysis determined optimal threshold values.

RESULTS

Compared to controls, cases had significantly smaller IFS (p < 0.001, both readers) and QFS (reader 1: p < 0.001; reader 2: p = 0.003). When stratified as preteen (< 13) or teenage (≥ 13), lower mean IFS and QFS were observed in cases versus controls in both age groups. Area under ROC curve for IFS and QFS was high in preteens (0.77 and 0.71) and teens (0.94 and 0.88). Threshold values were 14.9 mm (preteens) and 19 mm (teens) for IFS and 11.2 mm (preteens) and 11.1 mm (teens) for QFS. IFS and QFS were modestly correlated with age among controls only.

CONCLUSIONS

Pediatric patients with QFME had significantly narrower QFS and IFS compared with controls. IFS and QFS were found to normally increase in size with age. Optimal cutoff threshold values were identified for QFS and IFS in preteens and teenagers.

Articular and peri-articular hip lesions in soccer players. The importance of imaging in deciding which lesions will need surgery and which can be treated conservatively?

Soccer is one of the most popular sports worldwide engaging millions of participants each year. During play, injuries occur rather frequently and most of them involve the hip joint and the surrounding structure. In professional athletes, injuries are often complex scenarios and in the case of misdiagnosis, patients' return to play is delayed or it may progress to a more serious injury with consequent damage for their career and for the soccer team. The most frequent articular pathologies are Femoro-acetabular impingement and labral tears. Stress fracture, avulsion, ischiofemoral impingement, subspine impingement, athletic pubalgia, muscle injuries and Morel-Levallèe lesion are the most frequent hip peri-articular pathologies whereas snapping hip may be both intra- or extra-articular pathology. With an increasing number of football players, the radiologist plays a crucial role in the detection and characterization of the extent of the injuries. This article reviews the current imaging concepts frequently seen in injuries around the hips of professional football players focusing in particular on the most suitable therapeutic approaches, whether surgical or conservative.

Imaging of the hip in juvenile idiopathic arthritis

Hip involvement is common and estimated to occur in approximately 35-63% of children with juvenile idiopathic arthritis (JIA). It is more prevalent in the aggressive systemic subtypes, with irreversible changes occurring as early as within 5 years of diagnosis. Whilst clinical parameters and joint examination can be useful for assessing disease severity, subclinical disease is known to exist and delayed treatment may herald a lifetime of disability and pain. Early recognition of JIA changes is therefore crucial in determining treatment options. Validated scoring systems in the radiologic assessment of the hip for clinical drug trials may inform treatment outcomes, although robust tools for analysis are still lacking. This review article details the modalities utilised for imaging the hip in children with JIA with particular efforts focused upon reliability and validity in their assessment of joint disease. We conclude with a short literature review on the potential future techniques being developed for hip joint imaging in JIA.

Acute ischiofemoral impingement?

We report a case of rare clinical entity, which comes within the spectrum of hip impingements. The case deals with a 36 year old female, Olympic athlete, who developed ischiofemoral impingement 14 months after a surgical hamstring reattachment. She was treated conservatively and fully recovered. When looking into literature on this matter, we found that it is probably an under-diagnosed problem, particularly in patients with no history of prior surgery. To our knowledge, this is the first case reported after a hamstrings tendon reattachment.

Twenty-Year Systematic Review of the Hip Pathology, Risk Factors, Treatment, and Clinical Outcomes in Artistic Athletes-Dancers, Figure Skaters, and Gymnasts

OBJECTIVE

To identify (1) the predominant level of evidence of the clinical studies regarding the hip pathology, risk factors, treatment, and clinical outcomes in artistic athletes (dancers, figure skaters, and gymnasts) (2) the most commonly reported hip pathology, risk factors, treatments, and clinical outcomes in dancers, figure skaters, and gymnasts.

METHODS

To conduct this systematic review PubMed, EMBASE, and Scopus databases were searched for relevant studies and pertinent data were collected from the eligible articles. Included were studies which reported hip injuries in artistic athletes, the risk factors, treatment, and/or the clinical outcomes. We excluded case reports or irrelevant studies. No meta-analysis was performed because of study heterogeneity. The methodical index for nonrandomized studies (MINORS) criteria were used for quality control.

MAIN RESULTS

Thirty-eight studies were included in the analysis. The mean MINORS score was 13.6 ± 4.6 points indicating fair quality of evidence of the included articles. The predominant level of evidence was level IV. Chondrolabral pathology and muscle injuries were the most commonly reported pathologies. We found only 2 risk factor analysis studies; however, many studies reported risk correlation between artistic sports or imaging findings and hip pathology. Treatment strategies were reported in only 7 studies, clinical outcomes are significantly underreported.

CONCLUSION

Chondrolabral pathology was the most commonly reported hip pathology in artistic athletes, however, prospective cohort studies are necessary to really understand these injuries and their associated risk factors. The lack of clinical outcomes is significant and future data collection is required to assess the effectiveness of the various treatments.

Extra-articular hip impingement: a review of the literature

Hip and groin pain is a common clinical problem. Multiple causes can generate hip or groin pain, often sharing clinical and demographic characteristics. Diagnostic imaging tests play an important role in the etiological diagnosis. New forms of extra-articular hip impingement have recently been recognized as a cause of hip pain and limited function especially in young active patients. These conditions include ischiofemoral impingement, anterior inferior iliac spine and subspine impingement, iliopsoas impingement and greater trochanteric-pelvic impingement. In general, they are caused by a mechanical conflict with an abnormal or excessive contact between the proximal femur and pelvis and/or soft tissue between them. In this manuscript we review the physiopathology, clinical presentation, the most common radiologic findings and treatment of these forms of extra-articular hip impingement.

MRI of the hip: current concepts on bone marrow oedema

Bone marrow oedema (BME) is commonly found in hip MR imaging. BME is a nonspecific finding which can be related to a wide variety of diseases. However, there are cases where its existence or its pattern can narrow the differential or even point to a specific diagnosis. Therefore, deep understanding of its pathophysiology is of utmost importance for clinicians and radiologists in order to avoid diagnostic pitfalls. We hereby present currently established knowledge on BME related to adult hip pathology, aiming to raise physicians' suspicion and to highlight that it is mandatory to combine specific imaging patterns with the history, clinical and laboratory findings in order to achieve accurate diagnosis.

Imaging of impingement syndromes around the hip joint

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

Hip Imaging in Athletes: Sports Imaging Series

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

ISCHIOFEMORAL IMPINGEMENT: ASSESSMENT OF MRI FINDINGS AND THEIR RELIABILITY

Objective:

To evaluate the Magnetic Resonance Imaging (MRI) findings and their validity in patients with ischiofemoral impingement syndrome (IFI) .

Methods:

We retrospectively analyzed 55 hips. MRI findings of 30 hips were consistent with IFI syndrome. Twenty five hips had no MRI findings consistent with IFI syndrome. We compared the ischiofemoral space (IFS), quadratus femoris space (QFS), ischial angle (IA) and femoral neck angle (FNA) between the age and gender matched groups. We also analyzed edema, fatty replacement and partial or total rupture of quadratus femoris muscle. Mann Whitney U test was used to compare the data.

Results:

We observed atrophy in eight, fatty replacement also in eight and edema in all of the quadratus femoris muscle. QFS (p<0.001) and IFS (p<0.001) were significantly lower in patients as compared to the control group. IA (p=0.012) and FNA (p=0.010) values were significantly higher in patients compared with the control group.

Conclusion:

MRI findings of IFI include narrowing of QFS and IFS and increase in IA and FNA. This condition should be kept in mind for patients with hip pain. Level of Evidence III, Retrospective Study.

Similar Prevalence of Acetabular Labral Tear in Professional Ballet Dancers and Sporting Participants

OBJECTIVE

To compare the prevalence of acetabular labral tear in male and female professional ballet dancers with age-matched and sex-matched sporting participants and to determine the relationship to clinical findings and cartilage defects.

DESIGN

Case-control study.

SETTING

Clinical and radiology practices.

PARTICIPANTS

Forty-nine (98 hips) male and female professional ballet dancers (current and retired) with median age 30 years (range: 19-64 years) and 49 (98 hips) age-matched and sex-matched sporting participants.

INDEPENDENT VARIABLES

Group (ballet or sports), sex, age, hip cartilage defects, history of hip pain, Hip and Groin Outcome Score, passive hip internal rotation (IR), and external rotation range of movement (ROM).

MAIN OUTCOME MEASURES

Labral tear identified with 3T magnetic resonance imaging (MRI).

RESULTS

Labral tears were identified in 51% of all 196 hips. The prevalence did not differ significantly between the ballet and sporting participants (P = 0.41) or between sexes (P = 0.34). Labral tear was not significantly associated with clinical measures, such as pain and function scores or rotation ROM (P > 0.01 for all). Pain provocation test using IR at 90° of hip flexion had excellent specificity [96%, 95% confidence intervals (CIs), 0.77%-0.998%] but poor sensitivity (50%, 95% CI, 0.26%-0.74%) for identifying labral tear in participants reporting hip pain. Older age and cartilage defect presence were independently associated with an increased risk of labral tear (both P < 0.001).

CONCLUSIONS

The prevalence of labral tear in male and female professional ballet dancers was similar to a sporting population. Labral tears were not associated with clinical findings but were related to cartilage defects, independent of aging.

CLINICAL RELEVANCE

Caution is required when interpreting MRI findings as labral tear may not be the source of the ballet dancer's symptoms.

Atraumatic tears of the ligamentum teres are more frequent in professional ballet dancers than a sporting population

OBJECTIVES

To compare the frequency of atraumatic ligamentum teres (LT) tear in professional ballet dancers with that of athletes, and to determine the relationship with clinical and imaging findings.

METHODS

Forty-nine male and female professional ballet dancers (98 hips) and 49 age and sex-matched non-dancing athletes (98 hips) completed questionnaires on hip symptoms and physical activity levels, underwent hip rotation range of movement (ROM) and hypermobility testing, and 3.0-Tesla magnetic resonance imaging (3 T MRI) on both hips to detect LT tears, acetabular labral tears, and articular cartilage defects, and to measure the lateral centre edge angles (LCE).

RESULTS

A higher frequency of LT tear was found in dancers (55 %) compared with athletes (22 %, P = 0.001). The frequency and severity of LT tears in dancers increased with older age (P = 0.004, P = 0.006, respectively). The Hip and Groin Outcome Score (HAGOS) pain scores or hip rotation ROM did not differ significantly among participants with normal, partial, or complete tears of LT (P > 0.01 for all). Neither the frequency of generalised joint hypermobility (P = 0.09) nor the LCE angles (P = 0.32, P = 0.16, left and right hips respectively) differed between those with and those without LT tear. In most hips, LT tear co-existed with either a labral tear or a cartilage defect, or both.

CONCLUSION

The higher frequency of atraumatic LT tears in professional ballet dancers suggests that the LT might be abnormally loaded in ballet, and caution is required when evaluating MRI, as LT tears may be asymptomatic. A longitudinal study of this cohort is required to determine if LT tear predisposes the hip joint to osteoarthritis.

Supine Versus Standing Radiographs for Detecting Ischiofemoral Impingement: A Propensity Score-Matched Analysis

OBJECTIVE

The purpose of this study was to assess parameters of ischiofemoral impingement on supine and standing anteroposterior hip radiographs and to suggest optimal cutoff points for detection of ischiofemoral impingement.

MATERIALS AND METHODS

A retrospective study included patients with a clinical history of hip pain. All hip joints with evidence of quadratus femoris muscle edema on MR images were included in the ischiofemoral impingement patient group. An age- and sex-matched control group was derived from the same cohort by propensity score matching. On radiographs, two readers independently measured the following parameters: ischiofemoral space, quadratus femoris space, hamstring tendon area, ischiofemoral distance on supine radiograph, ischiofemoral distance on standing radiograph, and femoral neck-shaft angle. Group differences in parameters were assessed by Mann-Whitney U test. The intraclass correlation coefficient and the ROC AUC were obtained. Correlations between radiographic and MRI measures were assessed with Pearson correlation and Bland-Altman plot analyses. The Youden J index was used to select optimum cutoff points for each parameter.

RESULTS

There were 30 patients (44 hip joints; mean age, 54.8 ± 11 years) in the ischiofemoral impingement group and 88 patients (88 hip joints; mean age, 51.8 ± 13.4 years) in the control group. There were significant group differences in ischiofemoral space, quadratus femoris space, ischiofemoral distance on supine radiograph, ischiofemoral distance on standing radiograph, and neck-shaft angle (p < 0.05). Ischiofemoral distance on supine and standing radiographs exhibited good discriminative ability (AUC > 0.80). The optimal cutoff points for ischiofemoral distances on supine and standing radiographs were 19.9 and 19.1 mm for reader 1 and 21.1 and 17.0 mm for reader 2. Ischiofemoral space, quadratus femoris space, ischiofemoral distance on supine radiograph, and ischiofemoral distance on standing radiograph exhibited nearly perfect interobserver agreement (r > 0.8).

CONCLUSION

Ischiofemoral distances on supine and standing hip radiographs had good diagnostic performance and can be used as a screening tool, with optimal cutoff points.

Ischiofemoral impingement syndrome: a meta-analysis

OBJECTIVE

The aims of this article are to review the imaging characteristics of ischiofemoral impingement (IFI), summarize measurement thresholds for radiologic diagnosis based on a meta-analysis of the literature and raise awareness among radiologists and clinicians of this entity.

MATERIALS AND METHODS

A PubMed search restricted to the English language containing the keywords "ischiofemoral impingement" and "quadratus femoris MRI" was performed, and citations in these articles were also used to identify a total of 27 studies discussing ischiofemoral impingement. After excluding case reports and non-representative studies, there were five remaining articles including 193 hip MRIs of IFI in 154 subjects (133 female, 21 male) and 135 asymptomatic control hip MRIs from 74 subjects (55 female, 19 male). Additionally, we performed a retrospective database search of pelvic and hip MRI reports from our institution including the terms "quadratus femoris" or "ischiofemoral impingement" from a 9-year period and 24 hip MRIs from 21 patients (18 female, 3 male) with IFI with 5 asymptomatic contralateral control hip MRIs identified. In all, 217 hip MRIs of IFI and 140 control cases were included. A meta-analysis of these hip MRIs was conducted to determine optimal thresholds of the ischiofemoral space (IFS) and quadratus femoris space (QFS) for identifying IFI.

RESULTS

Cases of IFI showed significantly smaller IFS and QFS compared to controls (14.91 ± 4.8 versus 26.01 ± 7.98 and 9.57 ± 3.7 versus 15.97 ± 6.07, measured in mm, respectively, p < 0.0001 for both). Pooled analysis revealed that for IFS, using a cutoff of ≤ 15 mm yielded a sensitivity of 76.9%, specificity of 81.0% and overall accuracy of 78.3%. For QFS, a cutoff of ≤ 10.0 mm resulted in 78.7% sensitivity, 74.1% specificity and 77.1% overall accuracy.

CONCLUSION

IFI is a potential cause of hip pain that can be accurately diagnosed with MRI in conjunction with clinical findings. Using the proposed measurement thresholds may better identify patients with this impingement syndrome so that optimal treatment options can be pursued.

Use of MR arthrography in detecting tears of the ligamentum teres with arthroscopic correlation

OBJECTIVE

To demonstrate the normal appearance of the ligamentum teres on MR arthrography (MRA) and evaluate the accuracy of MRA in detecting ligamentum teres tears with arthroscopic correlation.

MATERIALS AND METHODS

Institutional Review Board approval was obtained with a waiver for informed consent because of the retrospective study design. A total of 165 cases in 159 patients (111 females, 48 males; mean age 41 ± 12 years) who underwent both MRA and hip arthroscopy were evaluated for appearance of the ligamentum teres, including the size, number of bundles, and ligamentum teres tears. Marrow edema of the fovea capitis adjacent to the ligamentum teres insertion and the presence of hip plicae were also recorded.

RESULTS

The mean thickness and length of the ligamentum teres were 3.5 ± 1.5 mm and 25.2 ± 3.8 mm, respectively. Sensitivity, specificity, positive and negative predictive value, and accuracy of MRA for the detection of ligamentum teres tears were 78, 97, 74, 97, and 95%, respectively.

CONCLUSION

MRA is an accurate method to evaluate the normal morphology and to detect tears of the ligamentum teres.