Sports Injuries about the Hip: What the Radiologist Should Know

Imaging of sports injuries in adolescents

Musculoskeletal injuries in adolescents tend to occur in particular locations and have distinct characteristics, as they affect an immature skeleton. Increased engagement in sports, extended training and competition periods, and early specialization in specific sports, among other factors, have contributed significantly to the rise in musculoskeletal sports injuries in adolescents. Furthermore, females show a particularly pronounced increase in sports participation, where anatomical and hormonal factors play crucial roles in the development and increased frequency of sports-related injuries. Consequently, there is a growing demand for diagnostic imaging techniques. Musculoskeletal and pediatric radiologists require a comprehensive understanding of intrinsic and extrinsic risk factors and the successive stages of skeletal development that can influence the specific characteristics of sports injuries in adolescents. These aspects are crucial for the diagnostic, prognostic, and therapeutic management of these injuries and for mitigating chronic conditions that could compromise future sports participation. This review analyzes the primary musculoskeletal injuries in adolescent athletes and highlights the pivotal role of different imaging methods in their diagnosis and management.

Enhancing regenerative potential: A comprehensive review of stem cell transplantation for sports-related neuronal injuries, with a focus on spinal cord injuries and peripheral nervous system damage

Neuronal injuries, as one of the consequences of sports-related incidents, exert a profound influence on the athletes' future, potentially leading to complete immobility and impeding their athletic pursuits. In cases of severe damage inflicted upon the spinal cord (SC) and peripheral nervous systems (PNS), the regenerative process is notably compromised, rendering it essentially inefficient. Among the pivotal therapeutic approaches for the enhancement and prevention of secondary SC injuries (SCI), stem cell transplantation (SCT) stands out prominently. Stem cells, whether directly involved in replacement and reconstruction or indirectly through modification and secretion of crucial bioenvironmental factors, engage in the intricate process of tissue regeneration. Stem cells, through the secretion of neurotrophic factors (NTFs) (aiming to modulate the immune system), reduction of inflammation, axonal growth stimulation, and myelin formation, endeavor to facilitate the regeneration of damaged SC tissue. The fundamental challenges of this approach encompass the proper selection of suitable stem cell candidates for transplantation and the establishment of an appropriate microenvironment conducive to SC repair. In this article, an attempt has been made to explore sports-related injuries, particularly SCI, to comprehensively review innovative methods for treating SCI, and to address the existing challenges. Additionally, some of the stem cells used in neural injuries and the process of their utilization have been discussed.

Hip Capsulolabral Complex: Anatomy, Disease, MRI Features, and Postoperative Appearance

The hip is a uniquely constrained joint with critical static stability provided by the labrum, capsule and capsular ligaments, and ligamentum teres. The labrum is a fibrocartilaginous structure along the acetabular rim that encircles most of the femoral head. Labral tears are localized based on the clock-face method, which determines the extent of the tear while providing consistent terminology for reporting. Normal labral variants can mimic labral disease and can be differentiated by assessment of thickness or width, shape, borders, location, and associated abnormalities. The Lage and Czerny classification systems are currently the most well-known arthroscopic and imaging systems, respectively. Femoroacetabular impingement is a risk factor for development of labral tears and is classified according to bone dysmorphisms of the femur ("cam") or acetabulum ("pincer") or combinations of both (mixed). The capsule consists of longitudinal fibers reinforced by ligaments (iliofemoral, pubofemoral, ischiofemoral) and circular fibers. Capsular injuries occur secondary to hip dislocation or iatrogenically after capsulotomy. Capsular repair improves hip stability at the expense of capsular overtightening and inadvertent chondral injury. The ligamentum teres is situated between the acetabular notch and the fovea of the femoral head. Initially considered to be inconsequential, recent studies have recognized its role in hip rotational stability. Existing classification systems of ligamentum teres tears account for injury mechanism, arthroscopic findings, and treatment options. Injuries to the labrum, capsule, and ligamentum teres are implicated in symptoms of hip instability. The authors discuss the labrum, capsule, and ligamentum teres, highlighting their anatomy, pathologic conditions, MRI features, and postoperative appearance. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

S.P.O.R.R.T.-A Comprehensive Approach to the Assessment and Non-Operative Management of Overuse Knee Conditions in Youth Athletes

PURPOSE OF REVIEW

The evaluation of a young athlete with an overuse injury to the knee involves a comprehensive approach. There are a number of elements to consider including assessments of skeletal maturity (biologic maturation), workload (training load + competition load), sport specialization status, and biomechanics. The type of injury and treatment, as well as future prognosis, may be influenced by these and other factors.

RECENT FINDINGS

Calculating the percentage of predicted adult height (PPAH) is a valuable tool in assessing overuse injury patterns and diagnoses in youth athletes. Modifiable and non-modifiable overuse injury risk factors require monitoring from clinicians as young athletes mature and develop over time. Training and rehabilitation programs should be adapted to account for these. In this manuscript, we seek to introduce a novel, comprehensive approach: S.P.O.R.R.T. (Skeletal Maturity, Prior Injury Risk, One Sport Specialization, Rehabilitation, Return to Play, Training Recommendations) (Fig. 1). Overuse, non-traumatic injuries to the knee in youth athletes will be presented in a case-based and evidence-based model to provide a framework for a comprehensive approach to the assessment and treatment of youth athletes with overuse injuries.

Team Approach: Hip Preservation Surgery

The evaluation and treatment of adolescents and young adults with hip pain has seen tremendous growth over the past 20 years. Labral tears are well established as a common cause of hip pain but often occur because of underlying bony abnormalities. Femoroacetabular impingement (FAI) and acetabular dysplasia are now well-established causes of hip osteoarthritis and are increasingly treated in the prearthritic stage in hopes of improving symptoms and prolonging the longevity of the native hip. Beyond FAI and acetabular dysplasia, this patient population can present with a complex and variable group of underlying conditions that need to be taken into account. Expertise in the conservative management of this population, including physical therapy, is valuable to maximize the success. Preoperative, surgical, and postoperative decision-making and care in this population is complex and evolving. A comprehensive, multidisciplinary approach to the care of this patient population has been used for over 20 years by our institution with great success. The purpose of this article is to review the "team-based approach" necessary for successful management of the spectrum of adolescent and young adult hip disorders.

Imaging of Overuse Injuries of the Hip

Overuse injuries of the hip are common, and clinical diagnosis may be difficult because of overlapping and nonspecific clinical symptoms. Imaging can play an essential role in guiding diagnosis and management. Femoroacetabular joint structural abnormalities result in various conditions that can predispose patients to early development of osteoarthritis. Repetitive stress on the skeletally immature hip can result in apophyseal injuries. Notable nonosseous overuse hip pathologies include athletic pubalgia, trochanteric bursitis, and injuries involving the iliopsoas myotendinous unit. Timely diagnosis of overuse injuries of the hip can facilitate improved response to conservative measures and prevent irreversible damage.

Imaging of common hip pathologies in runners

Running is an increasingly popular sport and form of exercise. Because of the importance of the hip in the biomechanics involved with running, forming the primary connection between the axial and appendicular skeleton of the lower extremities, accurate diagnosis and reporting of hip pathology are vital for appropriate management. This review provides an overview of the most common hip pathologies and injuries encountered in runners. Radiologic studies, primarily conventional radiography and magnetic resonance imaging (MRI) provide useful diagnostic information and should be used in combination with clinical findings to help guide therapeutic management.

Beyond the Hip Labrum: A Pictorial Review

Magnetic resonance arthrography and 3T magnetic resonance imaging of the hip are a technique commonly performed in young, physically active patients presenting with pain relating to the hip, with the focus on assessing for the presence of labral tears and femoroacetabular impingement. Abnormal signal within the labrum can be misleading, however, as labral tears are a frequent incidental finding and have been identified in a large proportion of the asymptomatic population. A range of extralabral conditions can cause hip-related pain in young patients, including pathology related to the bones, joints, and periarticular soft tissues. It is vital that the radiologist is aware for these pathologies and examines for them even in the presence of a confirmed labral tear. In this article, we review a range of common extralabral pathologies responsible for hip pain and highlight review areas that aid in their diagnosis.

External snapping hip: classification based on magnetic resonance imaging features and clinical correlation

BACKGROUND

With the increasing sport population, the number of patients with external snapping hip (ESH) has also increased. To detect and visualise pathological soft tissue changes, magnetic resonance imaging (MRI) has been 1 of the most useful modalities. However, only limited studies have investigated MRI and its clinical value in the treatment of ESH in the past.

MATERIALS AND METHODS

Between May 2017 and November 2018, 104 patients were diagnosed with ESH at our institution. We excluded patients who did not undergo an MRI (n = 11), had complaint of bilateral symptom (n = 17), were not diagnosed hip problems previously (n = 2), and were lost-follow-up within 6 months (n = 19). After applying the exclusion criteria, 55 patients remained. We classified the patients into 2 groups according-MRI findings: tensed iliotibial band (ITB) and hypertrophied gluteus maximus (GM). We investigated the clinical findings, such as mean age, symptom duration, pain score, grading based on symptom severity, and other radiological findings such as soft tissue signal change and ITB thickness. The variables were compared between the groups.

RESULTS

Between the 2 groups defined by MRI findings, the group characterised by tense ITB showed a relatively short symptom duration than the hypertrophied GM group (p < 0.001). No significant differences in the other variables were found between the groups.

CONCLUSIONS

ESH has 2 types of MRI features. Compared with the hypertrophied GM group, the tense ITB group showed a shorter symptom duration and a more reversible status.

Ultrasound in Sports Injuries

Utilization of musculoskeletal ultrasound, in particular for sports medicine, has dramatically increased in recent years. Ultrasound is an important adjunct tool to physical examination and other imaging methods in the evaluation and management of the injured athlete. It offers unique advantages in specific clinical scenarios. Dedicated training and a standardized scanning technique are important to overcome the inherent operator dependence and avoid diagnostic pitfalls. Ultrasound guidance can also improve accuracy in targeted percutaneous injection therapies. This article reviews the general ultrasound appearance of muscle, tendon, ligament, and nerve abnormalities in the athlete with a focus on sport-specific injuries.

Hip Pain: Imaging of Intra-articular and Extra-articular Causes

Hip pain is a common and complex clinical entity. The causes of hip injuries in athletes are many and diverse, requiring efficient, accurate diagnosis for proper management. Imaging is an important step in the clinical evaluation of hip pain, and familiarity with multiple imaging modalities as well as characteristic imaging findings is a helpful tool for sports medicine clinicians. This article discusses imaging recommendations and gives imaging examples of common causes of intra-articular and extra-articular hip pain including femoroacetabular impingement, labral tears, cartilage defects, ligamentum teres injuries, snapping hip syndrome, femoral stress injuries, thigh splints, athletic pubalgia, avulsion injuries, and hip dislocation.

Cross-sectional Study of the Hip Joint Condition in Young Baseball Players

Objective

The hip joint is a crucial part of the kinetic chain for throwing baseball pitches. Nevertheless, few reports have described assessments of the functional development of the hip joint in young baseball players.

Methods

We examined 315 young baseball players, 7-14 years old, all of whom had completed a self-administered questionnaire including items related to the dominant side and throwing-related hip joint pain sustained during the previous year. We measured the hip ranges of motion (ROMs: external and internal rotation and flexion) and hip muscle strengths (external and internal rotation) on the dominant and non-dominant sides. The differences of hip ROMs and muscle strengths between the dominant and non-dominant sides and between age groups were investigated. Correlations were calculated between the players ages and hip ROMs and muscle strengths.

Results

No baseball player reported hip pain. The hip external rotation on the dominant side was smaller than that on the non-dominant side, whereas the hip internal rotation on the dominant side was greater than that on the non-dominant side. However, no significant difference was found between the dominant and non-dominant sides in terms of the hip muscle strength. Significant positive associations were found between the player's age and hip muscle strengths, whereas significant negative associations were found between the age and hip ROMs.

Conclusions

Our data concerning the relationship between age and hip joint development could be useful for supporting strategies for the prevention and rehabilitation of throwing injuries; however, hip injuries might be rare among young baseball players.

A three-dimensional measurement method on MR arthrography of the hip to classify femoro-acetabular impingement

PURPOSE

(1) To investigate correlations between different types of FAI and the ratio of acetabular volume (AV) to femoral head volume (FV) on MR arthrography. (2) To assess 2D/3D measurements in identifying different types of FAI by means of cut-off values of AV/FV ratio (AFR).

MATERIALS AND METHODS

Alpha angle, cranial acetabular version, acetabular depth, lateral center edge angle, AV, and FV of 52 hip MR arthrography were measured. ANOVA test correlated different types of FAI with AFR. ROC curves classified FAI by cut-off values of AFR. Accuracy of 2D/3D measurements was calculated.

RESULTS

ANOVA test showed a significant difference of AFR (p value < 0.001) among the three types of FAI. The mean values of AFR were 0.64, 0.74, and 0.89 in cam, mixed, and pincer types, respectively. Cut-off values of AFR were 0.70 to distinguish cam types from mixed and pincer types, and 0.79 to distinguish pincer types from cam and mixed types. Cut-off values identified 100%, 73.9%, and 55.6% of pincer, cam, and mixed types. 2D and 3D classifications of FAI showed accuracy of 40.4% and 73.0%.

CONCLUSIONS

3D measurements were clearly more accurate than 2D measurements. Distinct cut-off values of AFR discriminated cam types from pincer types and identified pincer types in all cases. Cam and mixed types were not accurately recognized.

Femoroacetabular impingement: correlation between imaging parameters, sport activity, and chondral damage

BACKGROUND

Femoroacetabular impingement is characterised by an abnormal contact between the acetabulum and the femoral head-neck junction. Femoroacetabular impingement shows three main clinical frameworks: Pincer-FAI, Cam-FAI and Cam-Pincer mixed form. The aim of the study was to investigate the correlation between femoroacetabular impingement, imaging, activity and chondral damages.

METHODS

Forty-one patients, undergoing arthroscopic chondroartroplasty for Cam and Cam-Pincer mixed form were considered. All patients underwent an X-ray hip evaluation (G1 group), while 15 patients also underwent a pelvis MRI evaluation (G2 subgroup). For G1 patients, the superior-inferior offset ratio and alpha angle were calculated from the X-ray examinations. For G2 patients, the antero-posterior offset ratio was also calculated from pelvis MRI. Chondral damage was classified according to the Outerbridge classification.

RESULTS

The superior-inferior offset ratio and the antero-posterior offset ratio were respectively 0.50 ± 0.23 and 0.33 ± 0.19. The α angle predictive for a chondral damage of IV degree was 81.5°.The chondral damage of the patients suffering from Cam-FAI and Cam-Pincer mixed form were respectively 3.53±0.80 and 3.00±1.41.

CONCLUSIONS

From the results was possible to: - Elaborate two tables providing a reliable indirect calculation of the alpha angle. - Establish an alpha angle cut-off value indicative for a IV degree chondral damage. - Show that Pincer-FAI does not represent an aggravating factor for chondral damage - Show that the level of sports activity was related to the severity of chondral damage. - Show that a physically demanding occupation was not an aggravating factor for chondral damage.

Hip Imaging and Injections

Athletic injuries of the hip often require radiographs and advanced imaging for diagnosis. Plain radiographs evaluate for osseous injury, provide a structural context behind an athlete's symptoms and examination, and offer a backdrop for interpretation of advanced imaging. An understanding of normal anatomy, imaging findings, and radiographic measurements allows for recognition of pathoanatomy and ability to diagnose accurately. Advanced imaging modalities, including magnetic resonance imaging, computed tomography, and ultrasonography, each play a role in evaluation of the athlete's hip. Although MRI and CT provide high-resolution imaging of the hip, ultrasonography offers the unique ability to perform dynamic imaging and guided injections.

[Radiological diagnosis of pelvic ring fractures]

EPIDEMIOLOGY

Traumatic fractures of the pelvic ring are relatively rare, but are associated with increased risk of mortality. Depending on injury mechanism and main vector of energy impact, a distinction is made between anteroposterior compression, lateral compression, and vertical shear (Young and Burgess classification), while the stability-related classification according to Tile distinguishes between type A (stable), type B (rotationally unstable) and type C (completely unstable). A comprehensive modern classification is given by the AO/OTA.

RADIOLOGICAL FRACTURE DIAGNOSIS

Plain pelvis x‑rays lack sufficient sensitivity but are still used to detect highly unstable pelvic fractures. CT has superior sensitivity and specificity. In addition to fracture classification, CT allows reliable assessment of associated vascular and bladder/urethral injuries and large soft tissue hemorrhage. MRI is unparalleled in showing bone marrow edema, cauda and plexus complications, and peripelvic soft tissue damage. MRI may also prove to be a valuable diagnostic tool for pelvic ring injuries in children, adolescents and young women, provided they are hemodynamically stable. Angiography, ultrasonography and bone scintigraphy are additional important diagnostic and therapeutic options.

PRACTICAL RECOMMENDATIONS

Knowledge of basic pelvic trauma mechanisms is important to understand the potential severity of traumatic pelvic fractures and to classify them correctly in terms of stability. Being familiar with typical concomitant injuries in pelvic ring fractures allows reliable diagnosis and their communication with the clinician. CT remains the "diagnostic workhorse". In fragile pelvic fractures, the often prolonged course with fracture progression must be taken into account, which is why MRI is of particular importance herein.

Magnetic resonance imaging of the hip: anatomy and pathology

The aim of this review is to outline the normal anatomy of the hip and to discuss common painful conditions of the hip that affect the general adult population. Hip pain is a common complaint with many different etiologies. In this review, hip pathologies are divided by location into osseous, intra-articular and extra-articular lesions. Magnetic resonance imaging (MRI) is the modality of choice for investigating painful hip conditions due to its multiplanar capability and high contrast resolution. This review focuses on the characteristic MRI features of common traumatic and pathologic conditions of the hip.

MRI assessment of anatomy and pathology of the iliofemoral ligament

The iliofemoral ligament is strongest ligament of the body. We review the magnetic resonance imaging (MRI) appearances of the iliofemoral ligament, and discuss the disease entities that may affect this region.

Imaging of chronic male pelvic pain: what the abdominal imager should know

Chronic pelvic pain is an important but underrecognized cause of morbidity in men. While there is abundant literature discussing female pelvic pain and the diagnostic role of imaging, much less attention has been given to imaging of non-gynecologic causes of chronic pelvic pain. Chronic pelvic pain in men can be a challenge to diagnose as pain may arise from visceral, musculoskeletal, or neurovascular pathology. Imaging of the pelvic viscera has been covered in detail elsewhere in this edition and therefore will not be reviewed here. We will focus upon topics less familiar to the abdominal radiologist, including imaging of pelvic floor, musculoskeletal, and neurovascular pathology.

Value of response to anesthetic injection during hip MR arthrography to differentiate between intra- and extra-articular pathology

PURPOSE

To determine the value of anesthetic injection during hip MR arthrography (anesthetic MRA) to differentiate between intra- and extra-articular pathology in patients with hip pain.

MATERIALS AND METHODS

This retrospective study was IRB-approved and HIPAA-compliant. We included 75 consecutive adult patients (46 women, mean age 38 ± 13 years) who were referred for MRA. All patients underwent a focused hip examination including active flexion, passive flexion, and passive flexion with internal and external rotation, immediately prior to injection. Anesthetic MRA was performed following fluoroscopically guided intra-articular injection of contrast mixed with anesthetic. Following the injection, the hip examination was repeated, and the pain response was recorded. Clinical records, including response to corticosteroid injections, physical therapy notes, and operative reports were reviewed for verification of intra- and extra-articular pathology as the source of hip pain (gold standard). The positive (PPV) and negative predictive values (NPP) of anesthetic MRA to differentiate between intra- and extra-articular pathology were calculated.

RESULTS

On MRI, 41 patients had only intra-articular and 5 patients only extra-articular pathology, while 29 patients had both, intra- and extra-articular pathology. Forty-three patients had pain relief and 32 patients had no pain relief after anesthetic injection. PPV of anesthetic MRA to detect intra-articular pathology was 91% and NPV was 67%.

CONCLUSION

Anesthetic MRA can be used as an adjunct to define the origin of hip pain. A positive response suggests intra-articular pathology which can be helpful to localize the source of pain in equivocal cases where both intra- and extra-articular pathology are evident on MRI.

Demographic and Radiographic Factors Associated With Intra-articular Hip Cartilage Injury: A Cross-sectional Study of 1511 Hip Arthroscopy Procedures

BACKGROUND

Moderate to severe (grade 3-4) hip joint cartilage injury seems to impair function in patients with femoroacetabular impingement syndrome.

PURPOSE

To investigate whether demographic and radiographic factors were associated with moderate to severe hip joint cartilage injury.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Patients were identified in the Danish Hip Arthroscopy Registry. The outcome variables were acetabular cartilage injury (modified Beck grade 0-2 vs 3-4) and femoral head cartilage injury (International Cartilage Repair Society grade 0-2 vs 3-4). Logistic regressions assessed the association with the following: age (<30 vs 30-50 years); sex; sport activity level (Hip Sports Activity Scale); alpha angle (AA) assessed as normal (AA <55°), cam (55°≤ AA <78°), or severe cam (AA ≥78°); lateral center-edge angle (LCEA) assessed as normal (25°≤ LCEA ≤ 39°), pincer (LCEA >39°), or borderline dysplasia (LCEA <25°); joint space width (JSW) assessed as normal (JSW >4.0 mm), mild reduction (3.1 mm ≤ JSW ≤ 4.0 mm), or severe reduction (2.1 mm ≤ JSW ≤ 3.0 mm).

RESULTS

A total of 1511 patients were included (mean ± SD age: 34.9 ± 9.8 years). Male sex (odds ratio [OR], 4.42), higher age (OR, 1.70), increased AA (cam: OR, 2.23; severe cam: OR, 4.82), and reduced JSW (mild: OR, 2.04; severe: OR, 3.19) were associated (P < .05) with Beck grade 3-4. Higher age (OR, 1.92), increased Hip Sports Activity Scale (OR, 1.13), borderline dysplasia (OR, 3.08), and reduced JSW (mild: OR, 2.63; severe: OR, 3.04) were associated (P < .05) with International Cartilage Repair Society grade 3-4.

CONCLUSION

Several demographic and radiographic factors were associated with moderate to severe hip joint cartilage injury. Most notably, increased cam severity and borderline dysplasia substantially increased the risk of grade 3-4 acetabular and femoral head cartilage injury, respectively, indicating that specific deformity may drive specific cartilage injury patterns in the hip joint.

Is Microfracture Necessary? Acetabular Chondrolabral Debridement/Abrasion Demonstrates Similar Outcomes and Survival to Microfracture in Hip Arthroscopy: A Multicenter Analysis

BACKGROUND

Hip arthroscopy is becoming more advanced and commonly performed. However, significant controversy exists regarding whether high-grade acetabular cartilage lesions should be treated with debridement/abrasion or microfracture. In addition, patients treated with microfracture are subject to extended protected weightbearing rehabilitation to mitigate risk of subchondral plate fracture and to protect fibrocartilage tissue formation.

PURPOSE

To determine the midterm patient-reported outcomes and failure rate of patients with grade 3 and 4 acetabular labrum articular disruption (ALAD) lesions managed with debridement/abrasion or microfracture.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Primary arthroscopic labral repair cases at 2 centers from November 2008 to April 2016 were reviewed for patients aged <55 years with unipolar ALAD grade 3 and 4 chondrolabral acetabular delamination. Patients undergoing microfracture and debridement/abrasion were compared using the visual analog pain scale (VAS), modified Harris Hip Score (mHHS), and Hip Outcome Score-Sports-Specific Subscale (HOS-SSS) to determine predictors of outcomes and failure.

RESULTS

A total of 113 hips in 110 patients (66 males, 44 females; mean age, 34.5 ± 1.1 years) undergoing debridement/abrasion (n = 82) or microfracture (n = 31) were followed for a mean of 4.9 years (range, 2.0-8.5 years). Lesion size was not statistically different between the debridement/abrasion (1.3 ± 1.0 cm²) and microfracture cohorts (1.4 ± 1.0 cm²) ( P = .47). Patients undergoing debridement/abrasion achieved 3.6-point mean improvements in VAS ( P < .01), 21.2-point improvements in mHHS ( P < .01), and 25.4-point improvements in HOS-SSS ( P < .01), which were not significantly different from those observed in microfracture patients ( P≥ .20). The 5-year rate of survival free of revision surgery was 84.0% in the debridement/abrasion group and 85.6% in the microfracture group ( P = .78). The cartilage treatment technique was found not to be predictive of revision risk during both univariate (hazard ratio [HR], 1.01; P = .98) and multivariate (HR, 0.93; P = .90) analysis accounting for patient age, lesion grade, and acetabular coverage.

CONCLUSION

Patients undergoing debridement/abrasion of high-grade unipolar acetabular cartilage lesions demonstrate similar outcome scores and revision rates compared with those of patients undergoing microfracture. These outcomes support the consideration of preferential debridement/abrasion at the discretion of the treating surgeon to optimize recovery while maintaining established positive outcomes after hip arthroscopy.

US Assessment of Sports-related Hip Injuries

Traumatic and overuse hip injuries occur frequently in amateur and professional athletes. After clinical assessment, imaging plays an important role in diagnosis and in defining care management of these injuries. Ultrasonography (US) is being increasingly used in assessment of hip injuries because of the wide availability of US machines, the lower cost, and the unique real-time imaging capability, which allows both static and dynamic evaluation as well as guidance of point-of-care interventions such as fluid aspiration and steroid injection. Accurate diagnosis of hip injuries is often challenging, given the complex soft-tissue anatomy of the hip and the wide spectrum of injuries that can occur. To conduct a skillful US evaluation of hip injuries, physicians must have pertinent knowledge of the normal anatomy and should make judicious use of surface anatomy landmarks while using a compartmentalized diagnostic approach. In this article, common sports-related injuries of the anterior, lateral, and posterior hip compartments are discussed. This review includes assessment of joint effusion, acetabular labral tear, acute and chronic tendon injuries including tendinopathy, partial and full-thickness tears, snapping hip syndromes, relevant US-guided procedures, and some other conditions such as Morel-Lavallée lesion and perineal nodular induration. Principles of care management and current knowledge on imaging findings that may affect return to activity are also presented. Using an oriented US examination technique and having knowledge of the normal hip anatomy will help physicians characterize US findings of common sports-related hip injuries and make accurate diagnoses. Online supplemental material is available for this article. ^©RSNA, 2018.

The epidemiology of MRI-detected pelvic injuries in athletes in the Rio de Janeiro 2016 Summer Olympics

OBJECTIVE

To describe the prevalence, severity and location of pelvic injuries, including hip, muscle and tendon pathologies, as assessed on MRI in athletes participating in the Rio de Janeiro 2016 Summer Olympic Games.

METHODS

We analyzed all pelvic MRIs that were acquired for suspected injury as reported by the National Olympic Committee (NOC) medical teams and the Organizing Committee medical staff during the Rio 2016 Summer Olympics. Diagnostic imaging was performed through the Olympic Village Polyclinic, using 3 T and 1.5 T MR scanners. Images were interpreted retrospectively according to standardized criteria.

RESULTS

A total of 11,274 athletes participated in the Games, of which 40 (0,4%) were referred for a pelvic MRI. Thirty-seven of the 40 (92%) had at least one abnormal finding, and some had as many as 17, for an average of 4.1 pathologies per examination. Almost half of all abnormal findings were assessed as pre-existing (46%). The majority of acute/subacute injuries were observed in track and field athletes (44%), whereas the highest number of pre-existing findings was seen in ball-sports athletes (39%). Forty-seven per cent of all acute/subacute injuries were muscle injuries with the gluteus maximus muscle the most commonly affected. In contrast, most pre-existing findings were detected at the symphysis (59%).

CONCLUSION

Our study demonstrated a high prevalence of both acute/subacute injuries and chronic changes in Olympic athletes undergoing pelvic MRI. Muscle injuries were the most common acute injuries, found mainly in track and field athletes. Most chronic changes were identified at the symphysis region in ball-sports athletes.

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 inguinal-related groin pain in athletes

Inguinal canal-related groin pain is common in athletes and may involve numerous structures such as the conjoint tendon and the transversalis fascia. Ultrasound is the only dynamic tool that shows the passage of preperitoneal fat at the level of the Hesselbach triangle and allows excluding true inguinal hernias. Fascia transversalis bulging and inguinal ring dilatation may also be described. MRI assesses injuries of rectus abdominis and adductor longus enthesis and osteitis symphysis but its accuracy for the diagnosis of inguinal-related groin pain remains debated.

Hip pathology: the diagnostic accuracy of magnetic resonance imaging

Background

Hip arthroscopy has led to a greater understanding of intra-articular hip pathology. Non-contrast magnetic resonance imaging (MRI) is currently the gold standard in non-invasive imaging diagnosis, with high sensitivity in identifying labral pathology but equivocal results for ligamentum teres damage and chondral defects.

The aim of this study is to determine the accuracy of non-contrast MRI for diagnosis of intra-articular hip derangements and identify radiological features that could increase the accuracy of the diagnosis.

Methods

A prospective study of 71 hips on 68 patients undergoing hip arthroscopy was conducted comparing pre-operative analysis of MRI imaging versus an arthroscopic examination. Two musculoskeletal radiologists reported the data independently. All hip arthroscopies were performed by a single surgeon. Patients with MRIs performed within 6 months before hip arthroscopy were included.

Outcome measures included observer accuracy identifying ligamentum teres tears, labral lesions, and chondral rim damage. Secondary outcome measures included inter-observer variability and correctly staged ligamentum teres tears.

Results

The accuracy of radiology reporting for ligamentum teres tears, labral damage, and chondral rim lesions was 85.92% for each instance. The MRI findings most consistent with labral tears include the presence of linear high signal traversing the articular surface into the labrum, presence of intra-labral fluid signal, and loss of homogenous low signal triangular morphology. Chondral rim damage was difficult to diagnose, but abnormal signal at the chondrolabral junction with partial thickness defects would suggest damage. Ligamentum teres tears are commonly found but poorly graded. Thickening and increased signal suggests synovitis while discontinuity and fraying suggests partial tearing.

Conclusion

Conventional non-arthrographic MRI offers an accurate non-invasive method to screen patients with symptoms referable to the hip by revealing the presence of labral tears, chondral defects, and ligamentum teres tears/synovitis. This study demonstrates that tears and synovitis of the ligamentum teres as potential sources of hip pain can be accurately identified on conventional non-arthrographic MRI. However, MRI has poor specificity and negative predictive value, and thus, a negative MRI result may warrant further investigation.

Musculoskeletal ultrasound: athletic injuries of the lower extremity

Athletic injuries of the lower extremities are commonly encountered in clinical practice. While some pathology can be diagnosed on physical exam, others are a clinical dilemma with nonspecific symptomatology. In these situations, ultrasound imaging can be utilized as an exceptional diagnostic tool, offering unique advantages over other imaging modalities. This article will review the imaging characteristics of commonly encountered athletic injuries of the lower extremity.