Hip Imaging in Athletes: Sports Imaging Series

Can gadolinium contrast agents be replaced with saline for direct MR arthrography of the hip? A pilot study with arthroscopic comparison

OBJECTIVE

To compare image quality and diagnostic performance of preoperative direct hip magnetic resonance arthrography (MRA) performed with gadolinium contrast agent and saline solution.

METHODS

IRB-approved retrospective study of 140 age and sex-matched symptomatic patients with femoroacetabular impingement, who either underwent intra-articular injection of 15-20 mL gadopentetate dimeglumine (GBCA), 2.0 mmol/L ("GBCA-MRA" group, n = 70), or 0.9% saline solution ("Saline-MRA" group, n = 70) for preoperative hip MRA and subsequent hip arthroscopy. 1.5 T hip MRA was performed including leg traction. Two readers assessed image quality using a 5-point Likert scale (1-5, excellent-poor), labrum and femoroacetabular cartilage lesions. Arthroscopic diagnosis was used to calculate diagnostic accuracy which was compared between groups with Fisher's exact tests. Image quality was compared with the Mann-Whitney U tests.

RESULTS

Mean age was 33 years ± 9, 21% female patients. Image quality was excellent (GBCA-MRA mean range, 1.1-1.3 vs 1.1-1.2 points for Saline-MRA) and not different between groups (all p > 0.05) except for image contrast which was lower for Saline-MRA group (GBCA-MRA 1.1 ± 0.4 vs Saline-MRA 1.8 ± 0.5; p < 0.001). Accuracy was high for both groups for reader 1/reader 2 for labrum (GBCA-MRA 94%/ 96% versus Saline-MRA 96%/93%; p > 0.999/p = 0.904) and acetabular (GBCA-MRA 86%/ 83% versus Saline-MRA 89%/87%; p = 0.902/p = 0.901) and femoral cartilage lesions (GBCA-MRA 97%/ 99% versus Saline-MRA 97%/97%; both p > 0.999).

CONCLUSION

Diagnostic accuracy and image quality of Saline-MRA and GBCA-MRA is high in assessing chondrolabral lesions underlining the potential role of non-gadolinium-based hip MRA.

KEY POINTS

• Image quality of Saline-MRA and GBCA-MRA was excellent for labrum, acetabular and femoral cartilage, ligamentum teres, and the capsule (all p > 0.18). • The overall image contrast was lower for Saline-MRA (Saline-MRA 1.8 ± 0.5 vs. GBCA-MRA 1.1 ± 0.4; p < 0.001). • Diagnostic accuracy was high for Saline-MRA and GBCA-MRA for labrum (96% vs. 94%; p > 0.999), acetabular cartilage damage (89% vs. 86%; p = 0.902), femoral cartilage damage (97% vs. 97%; p > 0.999), and extensive cartilage damage (97% vs. 93%; p = 0.904).

Particularities on Anatomy and Normal Postsurgical Appearances of the Hip

Detailed knowledge of anatomy helps to understand pathologic processes. This article focuses on the anatomy and functionality of the hip, with emphasis on recently studied concepts and anatomic features that have an association with the development of symptoms. The most common anatomic variants posing a challenge for diagnosis and other common findings in asymptomatic patients are reviewed. Good understanding of the different surgical procedures helps in providing as much information as possible to guarantee a favorable outcome, improving prognosis. We review what are the commonly expected postsurgical appearances and the most common postsurgical complications.

Dynamic ultrasound assessment of hip instability and anterior and posterior hip impingement

OBJECTIVE

In this technical report, we describe our protocol for the dynamic sonographic evaluation of the hip and assess reliability of the ultrasound assessment of hip microinstability.

MATERIALS AND METHODS

Our clinical experience with a standardized dynamic ultrasound of the hip performed in a series of 27 patients with imaging performed by an experienced musculoskeletal radiologist during physical examination by an orthopedic surgeon specializing in hip preservation is illustrated with clinical photographs and ultrasound images from volunteers and selected patients. Interrater reliability for the diagnosis of microinstability was calculated.

RESULTS

Dynamic ultrasound technique and findings of hip instability, femoroacetabular impingement, and ischiofemoral impingement with corresponding clinical photos showing the necessary physical examination maneuvers are described. Interrater agreement for the diagnosis of microinstability was substantial (κ 0.606 [0.221-0.991]).

CONCLUSION

At our institution, dynamic ultrasound of the hip during physical examination complements information gathered from static imaging by providing real-time correlation of symptoms with what is occurring anatomically.

Imaging Review of Alpine Ski Injuries

Skiing is a continuously evolving winter sport, responsible for a considerable number of musculoskeletal injuries. Specific injury patterns and mechanisms in the upper and lower extremities, head, and spine are influenced by skier expertise and skill, position during injury, and environmental conditions. Predilection for certain joints and injury patterns have changed over time, largely due to technological advancements in equipment, increased awareness campaigns, and preventive protocols. Knowledge and understanding of these trends and developments can aid the radiologist to reach a timely and accurate diagnosis, thereby guiding clinical management and potentially reducing the overall incidence of debilitation and death.

Evaluation of CT-Guided Ultra-Low-Dose Protocol for Injection Guidance in Preparation of MR-Arthrography of the Shoulder and Hip Joints in Comparison to Conventional and Low-Dose Protocols

To evaluate patients’ radiation exposure undergoing CT-guided joint injection in preparation of MR-arthrography. We developed a novel ultra-low-dose protocol utilizing tin-filtration, performed it in 60 patients and compared the radiation exposure (DLP) and success rate to conventional protocol (26 cases) and low-dose protocol (37 cases). We evaluated 123 patients’ radiation exposure undergoing CT-guided joint injection from 16 January–21 March. A total of 55 patients received CT-guided joint injections with various other examination protocols and were excluded from further investigation. In total, 56 patients received shoulder injection and 67 received hip injection with consecutive MR arthrography. The ultra-low-dose protocol was performed in 60 patients, the low-dose protocol in 37 patients and the conventional protocol in 26 patients. We compared the dose of the interventional scans for each protocol (DLP) and then evaluated success rate with MR-arthrography images as gold standard of intraarticular or extracapsular contrast injection. There were significant differences when comparing the DLP of the ultra-low-dose protocol (DLP 1.1 ± 0.39; p < 0.01) to the low dose protocol (DLP 5.3 ± 3.24; p < 0.01) as well as against the conventional protocol (DLP 22.9 ± 8.66; p < 0.01). The ultra-low-dose protocol exposed the patients to an average effective dose of 0.016 millisievert and resulted in a successful joint injection in all 60 patients. The low dose protocol as well as the conventional protocol were also successful in all patients. The presented ultra-low-dose CT-guided joint injection protocol for the preparation of MR-arthrography demonstrated to reduce patients’ radiation dose in a way that it was less than the equivalent of the natural radiation exposure in Germany over 3 days—and thereby, negligible to the patient.

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.

[Differential diagnoses of inflammatory hip joint]

Die Differenzialdiagnosen der entzündlichen Hüfterkrankung spielen für die Diagnose des Hüftschmerzes eine bedeutende Rolle. Die rheumatologischen/entzündlichen Veränderungen des Hüftschmerzes mit dem entsprechenden Einsatz der Bildgebung wurden in Teil 1 des CME-Artikels abgehandelt. In diesem zweiten Teil wird ein systematischer Zugang erläutert, um die zahlreichen rheumatologischen Erkrankungen von Degenerationen, synovialen Tumoren und Infektionen zu unterscheiden. Die Interpretation der Pathologien in der Bildgebung im Zusammenhang mit dem klinischen Erscheinungsbild wird für die einzelnen Differenzialdiagnosen genauer erläutert. Das zeitgleiche Auftreten von unterschiedlichen Erkrankungen, zum Teil als sekundäre Komplikation, hat einen erheblichen Einfluss auf die Therapieplanung und sollte vom Radiologen erkannt werden.

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.

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.

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.

The Lisbon Agreement on Femoroacetabular Impingement Imaging-part 1: overview

OBJECTIVES

Imaging assessment for the clinical management of femoroacetabular impingement (FAI) syndrome remains controversial because of a paucity of evidence-based guidance and notable variability in clinical practice, ultimately requiring expert consensus. The purpose of this agreement is to establish expert-based statements on FAI imaging, using formal techniques of consensus building.

METHODS

A validated Delphi method and peer-reviewed literature were used to formally derive consensus among 30 panel members (21 musculoskeletal radiologists and 9 orthopaedic surgeons) from 13 countries. Forty-four questions were agreed on, and recent relevant seminal literature was circulated and classified in five major topics ('General issues', 'Parameters and reporting', 'Radiographic assessment', 'MRI' and 'Ultrasound') in order to produce answering statements. The level of evidence was noted for all statements, and panel members were asked to score their level of agreement with each statement (0 to 10) during iterative rounds. Either 'consensus', 'agreement' or 'no agreement' was achieved.

RESULTS

Forty-seven statements were generated, and group consensus was reached for 45 (95.7%). Seventeen of these statements were selected as most important for dissemination in advance. There was no agreement for the two statements pertaining to 'Ultrasound'.

CONCLUSION

Radiographic evaluation is the cornerstone of hip evaluation. An anteroposterior pelvis radiograph and a Dunn 45° view are recommended for the initial assessment of FAI although MRI with a dedicated protocol is the gold standard imaging technique in this setting. The resulting consensus can serve as a tool to reduce variability in clinical practices and guide further research for the clinical management of FAI.

KEY POINTS

• FAI imaging literature is extensive although often of low level of evidence. • Radiographic evaluation with a reproducible technique is the cornerstone of hip imaging assessment. • MRI with a dedicated protocol is the gold standard imaging technique for FAI assessment.

The Effect of Modality and Landmark Selection on MRI and CT Femoral Torsion Angles

Background Assessment of femoral torsion at preoperative hip imaging is commonly recommended. However, it is unclear whether MRI is as accurate as CT and how different methods affect femoral torsion measurements. Purpose To compare MRI- and CT-based assessment of femoral torsion by using four commonly used measurement methods in terms of agreement, reproducibility, and reliability and to compare femoral torsion angles between the four different measurement methods. Materials and Methods This retrospective study evaluated patients with hip pain who underwent CT and 3-T MRI of the hip including sequences of the pelvis and distal condyles between May 2017 and June 2018. The four measurement methods differed regarding the landmark levels for the proximal femoral reference axis and included measurements at the level of the greater trochanter, femoral neck, base of the femoral neck, and level of the lesser trochanter. Intraclass correlation coefficients (ICCs) were calculated, and Bland-Altman analysis was performed. Results Forty-five patients (mean age ± standard deviation, 19 years ± 5; 27 female) and 57 hips were evaluated. Inter- and intrarater reliability were excellent for each of the four CT- and MRI-based measurement methods (ICC range, 0.97-0.99). Mean difference between CT- and MRI-based measurement ranged from 0.3° ± 3.4 (P = .58) to 2.1° ± 4.1 (P < .001). Differences between CT and MRI were within the corresponding ICC variation for all four measurement methods. Mean torsion angles were greater by 17.6° for CT and 18.7° for MRI (all P < .001) between the most proximal to the most distal measurement methods. Conclusion MRI- and CT-based femoral torsion measurements showed high agreement and comparable reliability and reproducibility but were dependent on the level of selected landmarks used to define the proximal reference axis. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Zoga in this issue.

Intra-articular pathology affects outcomes after joint preserving surgery for osteonecrosis of the femoral head

PURPOSE

Currently, knowledge regarding the intra-articular pathology and its relationship to outcomes after joint-preserving surgery in patients with osteonecrosis of the femoral head (ONFH) is lacking. The purposes were to evaluate the intra-articular pathology and its relationship with outcomes of joint-preserving surgery in ONFH.

METHODS

We reviewed 41 hips with ONFH in 41 patients (27 women; mean age, 34.9 years old) who underwent intertrochanteric curved varus osteotomy. Radiographic evaluations were based on pre-operative imaging studies, including radiographs, computed tomography (CT), and magnetic resonance imaging (MRI). Intra-articular pathology was evaluated by arthroscopic inspection of the femoral head, labrum, and acetabular cartilage during surgery. In addition, we performed radiographic measurements of the hip, including the collapse of the femoral head and minimal joint space width at three  years post-operatively and at final follow-up.

RESULTS

Arthroscopy revealed damage to the acetabular cartilage and labrum in 22 (54%) and 13 patients (32%), respectively. However, these lesions could be detected on imaging in only 13 (32%) and ten patients (24%), respectively. The change in joint space width after surgery was significantly higher in patients with cartilage degeneration and labral injury (P = 0.02, P = 0.02). Logistic regression analysis for subsequent progression of osteoarthritis showed an association with degenerative changes of articular cartilage and the labral tear as independent predictors (P = 0.001, P = 0.03).

CONCLUSIONS

Our data demonstrate the presence of labral and acetabular cartilage lesions in ONFH patients, while images do not reveal the full extent of the tissue damage. These intra-articular pathologies can be associated with the outcomes after joint-preserving surgery.

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.

Prevalence of MRI-Detected Ankle Injuries in Athletes in the Rio de Janeiro 2016 Summer Olympics

OBJECTIVE

To describe the prevalence, severity, and location of ankle injuries as assessed on magnetic resonance imaging (MRI) in athletes participating in the Rio de Janeiro 2016 Summer Olympic Games.

METHODS

We analyzed all ankle MRIs that were acquired for suspected injury as reported by the National Olympic Committee medical teams and the Organizing Committee medical staff during the Rio 2016 Summer Olympics. Diagnostic imaging was performed through the Olympic Village Polyclinic. Images were interpreted retrospectively according to standardized criteria.

RESULTS

A total of 11,274 athletes participated in the Games, of which 89 (8.8%) were referred for an ankle MRI. Eighty-eight of the 89 (99%) had at least 1 abnormal finding, and some had as many as 27, for an average of 6.2 abnormalities per examination. Around one-fifth of all abnormal findings were considered pre-existing (21%) and 79% were assumed to be the result of an acute or subacute injury. The highest proportion of acute/subacute injuries per athlete occurred in ball sports (7.0 injuries per examination) and in the age group >30. Most pre-existing findings per athlete were identified in the group of others (no track and field or ball sports athletes) with 2.5 findings per examination and respectively in the age group >30 (1.7).

CONCLUSION

Our study demonstrated a high prevalence of acute and subacute, but also pre-existing injuries in Olympic athletes undergoing ankle MRI. Tendon injuries were the most common acute injuries, found mainly in ball sports athletes. Most pre-existing ankle injuries were identified at the ligaments.

Usefulness of MR Arthrography of the Hip with and without leg Traction in Detection of Intra-articular Bodies

RATIONALE AND OBJECTIVE

Although intra-articular bodies are a classic indication for MR arthrography and surgical removal, diagnostic studies are currently sparse. To assess the diagnostic performance of MR arthrography with and without leg traction in detection of intra-articular bodies in the hip joint.

MATERIAL AND METHODS

The institutional hip arthroscopy data base (2009-2016: 631 hips) was retrospectively reviewed. Inclusion criteria were hips with and without intra-articular bodies and direct MR arthrography performed with and without leg traction. Twenty-one hips with intra-articular bodies constituted the "disease-positive" group. Seventy-nine randomly selected hips without intra-articular bodies constituted the "disease-negative" group. Images were reviewed independently for presence of intra-articular bodies by two blinded readers. Overall diagnosis and location of intra-articular bodies was recorded (peripheral or central). Arthroscopy served as goldstandard for diagnosis and location of intra-articular bodies. Diagnostic performance and kappa statistics of traction MR arthrography with and without traction were calculated.

RESULTS

For both readers sensitivity/specificity of traction MR arthrography was 86%-95% respectively 90%-91% for overall diagnosis of intra-articular bodies and was 81%-86% respectively 90%-92%for MR arthrogrpahy without traction. For central intra-articular bodies sensitivity was higher for both readers with traction (79%-89%) than without traction (74% each).

CONCLUSION

MR arthrography with and without traction of the hip is highly accurate in identifying central and peripheral intra-articular bodies. Application of traction was further useful for visualization of centrally located intra-articular bodies.

Surface Mapping of the Musculotendinous Attachments at the Pubic Symphysis in Cadaveric Specimens: Implications for the Treatment of Core Muscle Injury

PURPOSE

To characterize the 3-dimensional muscular, musculotendinous, and neurovascular anatomy about the pubic symphysis relevant to core muscle injury (CMI).

METHODS

Ten cadaveric hips were dissected to characterize the musculotendinous insertion of the rectus abdominis and inguinal ligament, origins of the adductor longus and adductor brevis, and the pubic cartilage plate. A 3-dimensional coordinate measuring system and data acquisition software were used to calculate structure cross-sectional area, and the landmark anatomical relationships to 1 another and relevant neurovascular structures.

RESULTS

All specimens were male with an average age of 62 ± 2 years. The mean footprints of the rectus abdominis, inguinal ligament, adductor longus, and adductor brevis were 8.4 ± 3.1, 1.2 ± 0.5, 3.8 ± 1.6, and 2.9 ± 1.3 cm², respectively. The mean pectineus and gracilis footprints were 6.3 ± 2.4 and 3.4 ± 0.9 cm², respectively. The mean cross-sectional area of the cartilage plate was 24.8 ± 5.6 cm². The adductor longus was an average 1.5 ± 0.25 cm from the adductor brevis and 0.69 ± 0.52 cm from the rectus abdominis. The genital branch of the genitofemoral nerve was an average of 4.3 cm (range, 2.8-6.4) lateral to the insertion of the inguinal ligament. The femoral vein and artery were 3.0 cm (range, 2.5-3.6) and 3.7 cm (range, 2.5-5.9) lateral to the inguinal ligament footprint. The obturator nerve was 2.5 cm (range, 1.6-3.4) lateral to the adductor longus.

CONCLUSIONS

Familiarity with the anatomy of the pubic symphysis is essential for surgeons treating patients with CMI. We have shown that this relatively small area is the site of many muscular, musculotendinous, and neurovascular structures with various sized footprints and described the 3-dimensional anatomy of the anterior pubic symphysis. The origin of the adductor longus lies in close proximity to other structures, such as the adductor brevis, the insertion of the rectus abdominis, and the obturator nerve. These findings should be considered when operating in this region and treating patients with chronic groin pain.

CLINICAL RELEVANCE

The anatomy of the pelvic region and pubic symphysis has not been well characterized. Intimate knowledge of relevant anatomy is essential to treating CMI, also known as athletic pubalgia or sports hernia.

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.

How, When, Why in Magnetic Resonance Arthrography: an International Survey by the European Society of Musculoskeletal Radiology (ESSR)

OBJECTIVES

To perform an online survey about the use of magnetic resonance arthrography (MRA) in clinical practice.

METHODS

We administered an online survey to all 1,550 members of the European Society of Musculoskeletal Radiology (ESSR) about MRA asking ten different questions. Subgroup analysis was performed between general and orthopaedic hospitals using χ² and Mann-Whitney U statistics.

RESULTS

One-hundred forty-eight answers were included (148/1,550, 9.5% of ESSR members). A median of 3,000 (interquartile range: 1,567.5-5,324.5) musculoskeletal MR examinations and a median of 125.5 MRAs (50.75-249) per institution were performed in 2016. Ratio between MRA and musculoskeletal MR was 4.7% (1.6%-9.0%). Using MRA, the most investigated joint was the shoulder followed by the hip (96.6%). The most common indications were the evaluation of instability, labrum, and rotator cuff (85.1%). Fluoroscopy represented the preferred injection guidance. A self-prepared mixture of Gadolinium/saline is preferred in general hospitals, while pre-diluted Gadolinium-based syringes are mainly used in orthopaedic hospitals (P=.010). The number of MRA performed at orthopaedic hospitals (284;83.75-449.50) was higher (P=.006) than that performed at general hospitals (115.50;44.75-234.25).

CONCLUSIONS

One out of twenty MR examinations is a MRA, with higher prevalence in orthopaedic hospitals. The shoulder and the hip are the most investigated joints. Instability, labrum, and cuff are the most common indications.

KEY POINTS

• The most common MRAs are shoulder and hip (96.6% of answers). • Most common clinical indications for MRA are instability, labrum, and rotator cuff (85.1% of answers). • Fluoroscopy represents the preferred guidance to inject joints (61.0% of answers). • The median number of MRA performed at orthopaedic hospitals (n=284) was significantly higher (P=.006) than that performed at general hospitals (n=115.50). • A self-prepared mixture of Gadolinium/saline solution is preferred in general hospitals (64.8%) compared to orthopaedic hospitals (36.0%; P=0.010).

Comprehensive Clinical Evaluation of Femoroacetabular Impingement: Part 1, Physical Examination

A thorough evaluation of the hip must include a comprehensive medical and surgical history focused on the hip joint, surrounding soft tissues, and the associated structures of the spine, pelvis, and lower extremities. These details can guide the physical examination and provide insight into the cause of the patient's chief complaints. A proper examination includes physical examination while the patient is in the upright, supine, prone, and lateral position, as well as an evaluation of gait. Guided by a thorough history, the physical examination enables the surgeon to distinguish between intra-articular and extra-articular contributors to hip pain, selection of appropriate imaging modalities, and ultimately supports medical decision making.

Comprehensive Clinical Evaluation of Femoroacetabular Impingement: Part 3, Magnetic Resonance Imaging

Radiologic imaging is an essential supplement to the physical examination in the evaluation of a patient with femoroacetabular impingement. Plain radiographs are the initial modality of choice for the evaluation of bony anatomy and pathology. Magnetic resonance imaging supplements the physical examination and standard radiographs by enabling qualitative and quantitative evaluation of both articular cartilage and soft tissues about the hip. Magnetic resonance imaging also provides improved 3-dimensional characterization of the bony anatomy owing to the multiplanar nature of this technique. This article describes a comprehensive approach to interpretation of magnetic resonance examination of the hip.

In vitro chondrocyte toxicity following long-term, high-dose exposure to Gd-DTPA and a novel cartilage-targeted MR contrast agent

OBJECTIVE

To determine the concentrations exhibiting toxicity of a cartilage-targeted magnetic resonance imaging contrast agent compared with gadopentetate dimeglumine (Gd-DT-PA) in chondrocyte cultures.

MATERIALS AND METHODS

A long-term Swarm rat chondrosarcoma chondrocyte-like cell line was exposed for 48 h to 1.0-20 mM concentrations of diaminobutyl-linked nitroxide (DAB4-DLN) citrate, 1.0-20 mM Gd-DTPA, 1.0 μM staurosporine (positive control), or left untreated. Cell appearance, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays of metabolic activity, quantitative PicoGreen assays of DNA content, and calcein-AM viability assays were compared.

RESULTS

At 1.0-7.5 mM, minimal decrease in cell proliferation was found for both agents. At all doses of both agents, cell culture appearances were similar after 24 h of treatment. At the higher doses, differences in cell culture appearance were found after 48 h of treatment, with dose-dependent declines in chondrocyte populations for both agents. Concentration-dependent declines in DNA content and calcein fluorescence were found after 48 h of treatment, but beginning at a lower dose of DAB4-DLN citrate than Gd-DTPA. Dose-dependent decreases in MTT staining (cell metabolism) were apparent for both agents, but larger effects were evident at a lower dose for DAB-DLN citrate. Poor MTT staining of cells exposed for 48 h to 20 mM DAB4-DLN citrate probably indicates dead or dying cells.

CONCLUSION

The minimal effect of the long-term exposure of model chondrocyte cell cultures to DAB4-DLN citrate and Gd-DTPA concentrations up to 7.5 mM (3x typical arthrographic administration) is supporting evidence that these doses are acceptable for MR arthrography. The findings are reassuring given that the experimental exposure to the contrast agents at sustained concentrations was much longer than when used clinically.