Imaging techniques for muscle injury in sports medicine and clinical relevance

Proximal Hamstring Avulsions: Surgical Versus Conservative Treatment Using a Shared Decision-Making Strategy

Background

Surgical treatment of patients with proximal hamstring avulsions provides good results; however, less is known about the outcome in patients who are offered conservative treatment.

Purpose

To investigate the effect of surgical or conservative treatment (decided by a shared decision strategy) of proximal hamstring avulsions.

Study Design

Cohort study; Level of evidence, 2.

Methods

A total of 24 patients with magnetic resonance imaging-verified proximal hamstring avulsion were included and had either surgical treatment (11 patients, 45% women; mean age, 50 ± 16 years) or conservative treatment (13 patients, 46% women; mean age, 50 ± 17 years). At baseline, 6 months and 12 months, all patients answered the Perth Hamstring Assessment Tool (PHAT) (0-100 scale) and Hip Sports Activity Scale (0-8 scale). Patients had their maximal hip extension strength and maximal strength at 30° and 90° of knee flexion measured in newton meters per kilogram using a handheld dynamometer. A minimal important change in PHAT was considered >7 points and a minimal important change in strength was considered >0.15 N·m/kg, respectively.

Results

The surgical group had a shorter time from injury to initiation of treatment compared with the conservative group (median: 15 vs 64 days; P = .02). The surgical group had a greater amount of retraction of the tendons compared with the conservative group (3 vs 2 cm; P = .04). From baseline to 12-month follow-up, the surgical and conservative groups improved their mean PHAT scores (35 points [95 CI, 24-45 points] and 20 points [95% CI, 9-31 points], respectively) reaching a median of 79 points (interquartile range [IQR], 66-95 points) in the surgical group and 75 points (IQR, 66-85 points) in the conservative group at the 12-month follow-up. Their Hip Sports Activity Scale levels at 12 months were 3 points (95% CI, 1-4 points) and 1 point (95% CI, 0-3 points) (not significant). Furthermore, the surgical and conservative groups improved their maximal hip extension strength by 0.61 N·m/kg (IQR, 0.42-0.80 N·m/kg) and 0.62 N·m/kg (IQR, 0.13-1.10 N·m/kg), respectively. Their maximal knee flexion strength at 30° improved by 0.52 N·m/kg (IQR, 0.29-0.74 N·m/kg) and 0.32 N·m/kg (IQR, 0.12-0.52 N·m/kg) and their maximal knee flexion strength at 90° improved by 0.28 N·m/kg (IQR, 0.19-0.37 N·m/kg) and 0.22 N·m/kg (IQR, 0.02-0.41 N·m/kg). At the 12-month follow-up, the side-to-side difference in maximal muscle strength was 6% and 7%, respectively, during hip extension and 19% to 25% and 16% to 17%, respectively, during knee flexion.

Conclusion

Twelve months after treatment of proximal hamstring avulsion, good clinical outcomes were seen when using a shared decision strategy regardless of whether the strategy led to surgical or conservative treatment.

Ultrasound Imaging in Diagnosis and Management of Lower Limb Injuries: A Comprehensive Review

Medical imaging tests are widely used to diagnose a broad spectrum of lower-limb injuries. Among these modalities, ultrasound (US) imaging has gained significant traction as a valuable diagnostic instrument for assessing conditions primarily affecting muscles, tendons, ligaments, and other soft tissues. However, there are important dilemmas related to the indications and possibilities of US in lower-limb injuries. Conflicting findings and approaches raise questions regarding the validity, accuracy, and usefulness of the US in that area. This narrative review attempts to summarize the current state of knowledge regarding US imaging of lower-limb injuries. The study provides a detailed discussion of the existing literature and contemporary insights on the diagnosis of lower-limb injuries using US examination, and draws attention to the role of the US in interventional procedures and monitoring of the healing process. The characteristics of normal muscles, tendons, and ligaments in US imaging are presented, along with the most commonly documented conditions affecting these tissues. Furthermore, the benefits and justifications for employing US in interventional procedures are discussed, ranging from platelet-rich plasma injections to physiotherapeutic treatments like percutaneous electrolysis. The study was further augmented with US pictures depicting various lower-limb injuries, mainly affecting young athletes. This article aims to review the role of US imaging in the diagnosis and management of common lower-limb injuries.

Magnetic Resonance Imaging Biomarkers of Muscle

This review is focused on the current status of quantitative MRI (qMRI) of skeletal muscle. The first section covers the techniques of qMRI in muscle with the focus on each quantitative parameter, the corresponding imaging sequence, discussion of the relation of the measured parameter to underlying physiology/pathophysiology, the image processing and analysis approaches, and studies on normal subjects. We cover the more established parametric mapping from T1-weighted imaging for morphometrics including image segmentation, proton density fat fraction, T2 mapping, and diffusion tensor imaging to emerging qMRI features such as magnetization transfer including ultralow TE imaging for macromolecular fraction, and strain mapping. The second section is a summary of current clinical applications of qMRI of muscle; the intent is to demonstrate the utility of qMRI in different disease states of the muscle rather than a complete comprehensive survey.

Classification of myo-connective tissue injuries for severity grading and return to play prediction: A scoping review

OBJECTIVES

To conduct a systematic literature search to identify currently used classifications of acute non-contact muscle injuries in sporting adults.

DESIGNS

Scoping review.

METHODS

A systematic literature search from January 1, 2010 to April 19, 2022 of Medline and SPORTDiscus yielded 13,426 articles that were screened for eligibility. Findings from included studies were qualitatively synthesized. Classifications and their grading, as well as outcomes and definitions were extracted.

RESULTS

Twenty-four classifications were identified from the 37 included studies, most of which had low evidence study designs. Majority (57 %) of classifications were published after 2009 and were mostly developed for hamstring or other lower limb injuries. The six most cited classifications accounted for 70 % of the reports (BAMIC, modified Peetrons, Munich, Cohen, Chan and MLG-R). Outcome reporting was sparse, making it difficult to draw conclusions. Still, significant relationships between grading and time to return to play were reported for the BAMIC, modified Peetrons, Munich and Cohen classifications. Other classifications either had a very low number of reported associations, reported no associations, reported inconclusive associations, or did not report an assessment of the association. Other outcomes were poorly investigated.

CONCLUSIONS

There is no agreed-upon use of muscle classification, and no consensus on definitions and terminology. As a result, reported outcomes and their relationship to severity grading are inconsistent across studies. There is a need to improve the generalizability and applicability of existing classifications and to refine their prognostic value. High-level evidence studies are needed to resolve these inconsistencies.

Driving healthcare forward: The potential of mobile MRI and CT units in streamlining radiological services in Saudi Arabia - A narrative review

BACKGROUND AND PURPOSE

This narrative review focuses on the role of mobile MRI and CT units in addressing the challenges of healthcare accessibility and patient wait times in Saudi Arabia. It underscores the growing demand for diagnostic imaging amid infrastructural and geographical barriers, emphasizing mobile units as innovative solutions for enhancing radiological services across diverse Saudi landscapes. The purpose of this study is to assess how these mobile technologies can mitigate service delays, improve patient outcomes, and support healthcare delivery in remote or underserved areas, reflecting on global trends towards more dynamic, patient-centered healthcare models.

METHODS

This review utilizes an expanded database search and refined keywords to ensure comprehensive literature coverage. The study focused on peer-review articles and grey literatures that directly examined the impact of these mobile units on healthcare accessibility, wait times, and service delivery. A thematic analysis identified significant contributions to accessibility improvements, emergency responses, and rural healthcare, highlighting areas for further research and policy development.

DISCUSSION

Mobile units have advanced technical specifications with high-field magnets and multi-slice CT scanners on par with fixed facilities. They prioritize patient comfort and safety with examination areas, control rooms, and waiting areas. Telemedicine capabilities allow real-time image transmission to specialists. Strategic deployment can address workforce shortages by distributing services equitably. Mobile units represent cost-effective solutions to expand healthcare access without fixed infrastructure.

CONCLUSION

Integration of mobile MRI and CT units in Saudi Arabia can transform access to diagnostic imaging by decentralizing services and directly reaching patients, including rural areas. Evidence shows mobile units reduce diagnostic delays and optimize resource use. Despite challenges, strategic investments and collaborations can overcome obstacles to make radiological services more equitable, flexible and patient-focused in Saudi Arabia.

Advanced MRI Approaches for Evaluating Common Lower Extremity Injuries in Basketball Players: Current and Emerging Techniques

Magnetic resonance imaging (MRI) can provide accurate and non-invasive diagnoses of lower extremity injuries in athletes. Sport-related injuries commonly occur in and around the knee and can affect the articular cartilage, patellar tendon, hamstring muscles, and bone. Sports medicine physicians utilize MRI to evaluate and diagnose injury, track recovery, estimate return to sport timelines, and assess the risk of recurrent injury. This article reviews the current literature and describes novel developments of quantitative MRI tools that can further advance our understanding of sports injury diagnosis, prevention, and treatment while minimizing injury risk and rehabilitation time. Innovative approaches for enhancing the early diagnosis and treatment of musculoskeletal injuries in basketball players span a spectrum of techniques. These encompass the utilization of T2, T1ρ, and T2* quantitative MRI, along with dGEMRIC and Na-MRI to assess articular cartilage injuries, 3D-Ultrashort echo time MRI for patellar tendon injuries, diffusion tensor imaging for acute myotendinous injuries, and sagittal short tau inversion recovery and axial long-axis T1-weighted, and 3D Cube sequences for bone stress imaging. Future studies should further refine and validate these MR-based quantitative techniques while exploring the lifelong cumulative impact of basketball on players' knees. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 2.

Ultrasound in sports traumatology

BACKGROUND

 Ultrasound (US) has numerous applications in sports traumatology. The technical progress of mobile US devices has led to increasing use of ultrasound as a primary diagnostic tool. New applications such as elastography and 3 D vascularization are used for special indications.

METHOD

 The purpose of this review is to present the current status of ultrasound in the diagnosis of sports injuries and sport traumatology including established applications and new technical advances. US is presented both in its comparison to other imaging modalities and as a sole diagnostic tool.

RESULTS AND CONCLUSION

 US can be used for initial diagnosis to improve the clinical examination and for intensive short-term follow-up imaging. The main areas of application are currently the diagnosis of acute muscle and tendon injuries as well as overuse injuries. In particular, the exclusion of structural muscle injuries can be adequately ensured with US in the majority of anatomical regions. The recently published guideline on fracture ultrasound has strengthened the clinical evidence in this area, especially in comparison to conventional radiography and in the development of algorithms and standards. The increasing use of mobile ultrasound equipment with adequate image quality makes US a location-independent modality that can also be used at training sites or during road games.

KEY POINTS

  · Typically used for quick, focused initial diagnostic assessment and short-term follow-up after injury. · Mobile US devices allow increased use in training centers and training camps. · New US applications (SWE, 3 D) increase standardization in follow-up of tendon injuries. · Targeted use of US for musculoskeletal diagnostic assessment saves money and frees up capacity.

CITATION FORMAT

· Lerchbaumer MH, Perschk M, Gwinner C. Ultrasound in sports traumatology. Fortschr Röntgenstr 2024; 196: 440 - 449.

Return to Play in the Professional Athlete

The management of any injury in elite athletes poses unique challenges distinct from the general population because the goal is rapid recovery and return to play (RTP) while simultaneously managing residual symptoms and minimizing risk of reinjury. The time required for treatment, recovery, and return to peak performance can have consequences for both the athlete and his or her team: financial implications, psychological stressors, team dynamics, and future performance. RTP after an injury in the professional athlete requires a complex decision-making process with many stakeholders. Several factors influence this decision, not the least of which is the type and mechanism of injury. This article provides an overview of the RTP process including nonmedical factors that may influence this decision, common injuries seen in professional athletes, injury patterns particular to certain popular sports, and imaging guidelines for such injuries.

#ReadyToplay: hamstring injuries in women's football - a two-season prospective cohort study in the Norwegian women's premier league

In this two-season prospective cohort study (2020-2021), we aimed to describe the characteristics, clinical findings and magnetic resonance imaging (MRI) findings of hamstring injuries in the Norwegian women's premier league. Hamstring injuries were examined by team physiotherapists using a standardised clinical examination and injury form. Injury location and severity (modified Peetrons classification) were graded based on MRI by two independent radiologists. Fifty-three hamstring injuries were clinically examined, 31 of these with MRI. Hamstring injuries caused 8 days (median) lost from football (interquartile range: 3-15 days, range: 0-188 days), most were non-contact and occurred during sprinting. Gradual-onset (53%) and sudden-onset injuries (47%) were evenly distributed. The injuries examined with MRI were classified as grade 0 (52%), grade 1 (16%) or grade 2 (29%). One proximal tendinopathy case was not graded. Grade 2 injuries caused more time loss than grade 0 (19 ± 8 vs. 7 ± 7 days, p = 0.002). Of injuries with MRI changes, 60% were in the m. biceps femoris, mainly the muscle-tendon junction, and 40% in the m. semimembranosus, most in the proximal tendon. Compared to previous findings from men's football, a higher proportion of hamstring injuries in women's football had a gradual onset and involved the m. semimembranosus, particularly its proximal tendon.

Tissue Characterization of Puborectalis Muscle From 3-D Ultrasound

Pelvic floor (PF) muscles have the role of preventing pelvic organ descent. The puborectalis muscle (PRM), which is one of the female PF muscles, can be damaged during child delivery. This damage can potentially cause irreversible muscle trauma and even lead to an avulsion, which is disconnection of the muscle from its insertion point, the pubic bone. Ultrasound imaging allows diagnosis of such trauma based on comparison of geometric features of a damaged muscle with the geometric features of a healthy muscle. Although avulsion, which is considered severe damage, can be diagnosed, microdamage within the muscle itself leading to structural changes cannot be diagnosed by visual inspection through imaging only. Therefore, we developed a quantitative ultrasound tissue characterization method to obtain information on the state of the tissue of the PRM and the presence of microdamage in avulsed PRMs. The muscle was segmented as the region of interest (ROI) and further subdivided into six regions of interest (sub-ROIs). Mean echogenicity, entropy and shape parameter of the statistical distribution of gray values were analyzed on two of these sub-ROIs nearest to the bone. The regions nearest to the bones are also the most likely regions to exhibit damage in case of disconnection or avulsion. This analysis was performed for both the muscle at rest and the muscle in contraction. We found that, for PRMs with unilateral avulsion compared with undamaged PRMs, the mean echogenicity (p = 0.02) and shape parameter (p < 0.01) were higher, whereas the entropy was lower (p < 0.01). This method might be applicable to quantification of PRM damage within the muscle.

Imaging of Muscle Injuries

Ultrasound (US) and MR imaging are the most common imaging modalities used to assess sports muscle injuries. The site of the muscle injury can be located at the peripheral aspect of the muscle (myofascial), within the muscle belly (musculotendinous), and with tendon involvement (intratendinous). Tears that affect the intramuscular tendon have a worse prognosis in terms of recovery time. US is an excellent method to evaluate muscle injuries, with high spatial and contrast resolution. MR imaging can be reserved for evaluation of professional athletes, surgical planning, differential diagnosis, and assessment of deep located and proximal muscle groups.

Lesão muscular: Fisiopatologia, diagnóstico e tratamento

O tecido muscular esquelético possui a maior massa do corpo humano, correspondendo a 45% do peso total. As lesões musculares podem ser causadas por contusões, estiramentos ou lacerações. A atual classificação separa as lesões entre leves, moderadas e graves. Os sinais e sintomas das lesões grau I são edema e desconforto; grau II, perda de função, gap e equimose eventual; grau III, rotura completa, dor intensa e hematoma extenso. O diagnóstico pode ser confirmado por ultrassom (dinâmico e barato, porém examinador-dependente); e ressonância magnética (RM) (maior definição anatômica). A fase inicial do tratamento se resume à proteção, ao repouso, ao uso otimizado do membro afetado e crioterapia. Anti-inflamatórios não hormonais (AINHs), ultrassom terapêutico, fortalecimento e alongamento após a fase inicial e amplitudes de movimento sem dor são utilizados no tratamento clínico. Já o cirúrgico possui indicações precisas: drenagem do hematoma, reinserção e reforço musculotendíneos.

Spatial frequency analysis detects altered tissue organization following hamstring strain injury at time of injury but not return to sport

Background

Hamstring strain injury (HSI) diagnosis is often corroborated using ultrasound. Spatial frequency analysis (SFA) is a quantitative ultrasound method that has proven useful in characterizing altered tissue organization. The purpose of this study was to determine changes in muscular tissue organization using SFA following HSI.

Methods

Ultrasound B-mode images were captured at time of injury (TOI) and return to sport (RTS) in collegiate athletes who sustained an HSI. Spatial frequency parameters extracted from two-dimensional Fourier Transforms in user-defined regions of interest (ROI) were analyzed. Separate ROIs encompassed injured and adjacent tissue within the same image of the injured limb and mirrored locations in the contralateral limb at TOI. The ROIs for RTS images were drawn to correspond to the injury-matched location determined from TOI imaging. Peak spatial frequency radius (PSFR) and the fascicular banded pattern relative to image background (Mmax%) were compared between injured and adjacent portions within the same image with separate paired t-tests. Within-image differences of SFA parameters in the injured limb were calculated and compared between TOI and RTS with Wilcoxon rank sum tests.

Results

Within the injured limb at TOI, PSFR differences in injured and healthy regions did not strictly meet statistical significance (p = 0.06), while Mmax% was different between regions (p < 0.001). No differences were observed between regions in the contralateral limb at TOI (PSFR, p = 0.16; Mmax%, p = 0.30). Significant within-image differences in PSFR (p = 0.03) and Mmax% (p = 0.04) at RTS were detected relative to TOI.

Conclusions

These findings are a first step in determining the usefulness of SFA in muscle injury characterization and provide quantitative assessment of both fascicular disruption and edema presence in acute HSI.

Activation of Superficial and Deep Finger Flexors Through Transcutaneous Nerve Stimulation

OBJECTIVE

Functional electrical stimulation (FES) is a common technique to elicit muscle contraction and help improve muscle strength. Traditional FES over the muscle belly typically only activates superficial muscle regions. In the case of hand FES, this prevents the activation of the deeper flexor muscles which control the distal finger joints. Here, we evaluated whether an alternative transcutaneous nerve-bundle stimulation approach can activate both superficial and deep extrinsic finger flexors using a high-density stimulation grid.

METHODS

Transverse ultrasound of the forearm muscles was used to obtain cross-sectional images of the underlying finger flexors during stimulated finger flexions and kinematically-matched voluntary motions. Finger kinematics were recorded, and an image registration method was used to capture the large deformation of the muscle regions during each flexion. This deformation was used as a surrogate measure of the contraction of muscle tissue, and the regions of expanding tissue can identify activated muscles.

RESULTS

The nerve-bundle stimulation elicited contractions in the superficial and deep finger flexors. Both separate and concurrent activation of these two muscles were observed. Joint kinematics of the fingers also matched the expected regions of muscle contractions.

CONCLUSIONS

Our results showed that the nerve-bundle stimulation technique can activate the deep extrinsic finger flexors, which are typically not accessible via traditional surface FES.

SIGNIFICANCE

Our nerve-bundle stimulation method enables us to produce the full range of motion of different joints necessary for various functional grasps, which could benefit future neuroprosthetic applications.

Potential Role of MRI Imaging for Myofascial Pain: A Scoping Review for the Clinicians and Theoretical Considerations

The most common cause of chronic musculoskeletal pain is chronic myofascial pain syndrome (MPS). MPS often presents with increased muscle stiffness, and the myofascial trigger point (MTrP). Imaging modalities have been used to identify the MTrP, but their role in the detection and diagnosis of MPS remains unclear. The purpose of this review was to identify evidence in literature for the use of imaging in the role of classifying and explaining the physiology of MTrPs. Since few imaging techniques have been performed on MTrPs, we explored the imaging techniques that can effectively image complex skeletal muscle microstructure, and how they could be used. As part of a scoping review, we conducted a systematic search from three medical databases (CINAHL, EMBASE and MEDLINE) from year to year to analyze past MTrP imaging, as well as analyzing imaging techniques performed on the microstructure of muscle. Previously, ultrasound has been used to differentiate active, latent MTrPs, but these studies do not adequately address their underlying anatomical structure. MRI remains the standard method of imaging skeletal muscle. The existing MRI literature suggests that the DTI technique can quantify muscle injury, strain, and structure. However, theoretically, HARDI and DKI techniques seem to provide more information for complex structural areas, although these modalities have a disadvantage of longer scan times and have not been widely used on skeletal muscle. Our review suggests that DTI is the most effective imaging modality that has been used to define the microstructure of muscle and hence, could be optimal to image the MTrP. HARDI and DKI are techniques with theoretical potential for analysis of muscle, which may provide more detailed information representative of finer muscle structural features. Future research utilizing MRI techniques to image muscle are necessary to provide a more robust means of imaging skeletal muscle and the MTrP.

Extracellular matrix at the muscle - tendon interface: functional roles, techniques to explore and implications for regenerative medicine

The muscle-tendon interface is an anatomically specialized region that is involved in the efficient transmission of force from muscle to tendon. Due to constant exposure to loading, the interface is susceptible to injury. Current treatment methods do not meet the socioeconomic demands of reduced recovery time without compromising the risk of reinjury, requiring the need for developing alternative strategies. The extracellular matrix (ECM) present in muscle, tendon, and at the interface of these tissues consists of unique molecules that play significant roles in homeostasis and repair. Better, understanding the function of the ECM during development, injury, and aging has the potential to unearth critical missing information that is essential for accelerating the repair at the muscle-tendon interface. Recently, advanced techniques have emerged to explore the ECM for identifying specific roles in musculoskeletal biology. Simultaneously, there is a tremendous increase in the scope for regenerative medicine strategies to address the current clinical deficiencies. Advancements in ECM research can be coupled with the latest regenerative medicine techniques to develop next generation therapies that harness ECM for treating defects at the muscle-tendon interface. The current work provides a comprehensive review on the role of muscle and tendon ECM to provide insights about the role of ECM in the muscle-tendon interface and discusses the latest research techniques to explore the ECM to gathered information for developing regenerative medicine strategies.

Adductor longus injury after electromechanical self-treatment: A case report

OBJECTIVE

This case report illustrates an unusual cause of hip adductor muscle injury due to overenthusiastic self-treatment of the previously overloaded adductor muscles. Also, post-injury therapeutic objectives and intervention to facilitate rapid participation in sports after the described process are provided.

CASE DESCRIPTION

A 27-year old male, professional soccer player presented with hip adductors pain and impairment due to electromechanical self-treatment of the affected area. He was evaluated using hip-strength assessments, self-report, ultrasonography (US), and magnetic resonance imaging (MRI) until complete functional recovery had occurred. Along with clinical presentation, diagnostic imaging showed evidence of an isolated injury to the adductor longus muscle. A well-structured rehabilitation and readaptation program was followed in order to ensure early recovery and optimal functional outcome.

OUTCOMES

The athlete was able to participate in a full soccer training session without any limitation 18 days after his self-treatment session. The patient returned to his previous level of performance by 3rd week post-injury.

CONCLUSION

To the authors' knowledge, this is the first report of muscle strain due to overenthusiasthic therapy. Although this is a rare complication of self-treatment procedures, patients and therapists should be aware of this risk in order to prevent and rapidly identify the lesion.

Traumatic abdominal wall injuries-a primer for radiologists

Traumatic abdominal wall injuries encompass a broad clinical and radiological spectrum and are identified in approximately 9% of blunt trauma patients. The most severe form of abdominal wall injury-a traumatic abdominal wall hernia-is seen in less than 1.5% of blunt abdominal trauma patients. However, the incidence of concurrent intra-abdominal injuries in these patients is high and can result in significant morbidity and mortality. Although the diagnosis of abdominal wall injuries is typically straight forward on CT, associated injuries may distract the interpreting radiologist in more subtle cases. Thus, it is important for the radiologist to identify abdominal wall injuries and their associated injuries on admission CT, as these injuries typically require surgical correction early in the course of their management. Untreated abdominal wall injuries subject the patient to increased risk of delayed bowel incarceration and strangulation. Therefore, it is important for the radiologist to be knowledgeable of injuries to the abdominal wall and commonly associated injuries to provide optimal patient triage and expedite management.

Intra-session and inter-rater reliability of spatial frequency analysis methods in skeletal muscle

Spatial frequency analysis (SFA) is a quantitative ultrasound (US) method originally developed to assess intratendinous tissue structure. This method may also be advantageous in assessing other musculoskeletal tissues. Although SFA has been shown to be a reliable assessment strategy in tendon tissue, its reliability in muscle has not been investigated. The purpose of this study was to examine the reliability of spatial frequency parameter measurement for a large muscle group within a healthy population. Ten participants with no history of lower extremity surgery or hamstring strain injury volunteered. Longitudinal B-mode images were collected in three different locations across the hamstring muscles. Following a short rest, the entire imaging procedure was repeated. B-mode images were processed by manually drawing a region of interest (ROI) about the entire muscle thickness. Four spatial frequency parameters of interest were extracted from the image ROIs. Intra- and inter-rater reliabilities of extracted SFA parameters were performed. Test-retest reliability of the image acquisition procedure was assessed between repeat trials. Intraclass correlation coefficients showed high intra- and inter-rater reliability (ICC(3,1) > 0.9 for all parameters) and good to moderate test-retest reliability (ICC(3,1) > 0.50) between trials. No differences in parameter values were observed between trials across all muscles and locations (p > 0.05). The high reliability metrics suggest that SFA will be useful for future studies assessing muscle tissue structure, and may have value in assessing muscular adaptations following injury and during recovery.

Correlating clinical assessment and MRI findings in diagnosing calf injuries in elite male Australian rules footballers

OBJECTIVE

Calf complex injuries represent a significant injury burden among Australian Rules athletes. To date, there has been limited research correlating clinical and radiological findings of pathology within the calf. The objective of this study is to determine how accurately magnetic resonance imaging (MRI) findings correlate with clinical measures of calf muscle complex pathology in elite male athletes.

MATERIALS AND METHODS

A prospective cohort study was conducted on Australian rules elite athletes. A cohort of 45 athletes underwent a high-load training session of approximately 10 km of running. Athletes were then assessed by a sports physiotherapist who made a diagnosis of no pathology, delayed onset muscle soreness, strain or other. Subsequently, the athletes underwent MRI of their bilateral calf complexes. Radiologists interpreted the MRI findings and radiological diagnosis were correlated with clinical diagnosis.

RESULTS

A total of 90 calf MRIs were performed. Correlation of clinical and radiological diagnosis occurred in 57 cases. Of the 33 cases which did not correlate, there were 4 radiologically significant acute calf strains in clinically asymptomatic athletes, 3 of which involved old scar tissue.

CONCLUSION

MRI may detect clinically insignificant injuries within the calf complex. If an athlete does not have any clinically relevant symptoms, abnormal signal on MRI may represent a different diagnosis to muscle strain. Signal change on MRI proximal to scar tissue may represent reactive oedema. Clinical history and examination should be correlated with radiological findings is recommended when diagnosing calf injury in elite athletes.

Associations Between Initial Clinical Examination and Imaging Findings and Return-to-Sport in Male Athletes With Acute Adductor Injuries: A Prospective Cohort Study

BACKGROUND

Time to return-to-sport (RTS) after acute adductor injuries varies among athletes, yet we know little about which factors determine this variance.

PURPOSE

To investigate the association between initial clinical and imaging examination findings and time to RTS in male athletes with acute adductor injuries.

STUDY DESIGN

Cohort study (Prognosis); Level of evidence, 2.

METHODS

Male adult athletes with an acute adductor injury were included within 7 days of injury. Standardized patient history and clinical and magnetic resonance imaging (MRI) examinations were conducted for all athletes. Athletes performed a supervised standardized criteria-based exercise treatment program. Three RTS milestones were defined: (1) clinically pain-free, (2) completed controlled sports training, and (3) first full team training. Univariate and multiple regression analyses were performed to determine the association between the specific candidate variables of the initial examinations and the RTS milestones.

RESULTS

We included 81 male adult athletes. The median duration for the 3 RTS milestones were 15 days (interquartile range, 12-28 days), 24 days (16-32 days), and 22 days (15-31 days), respectively. Clinical examination including patient history was able to explain 63%, 74%, and 68% of the variance in time to RTS. The strongest predictors for longer time to RTS were pain on palpation of the proximal adductor longus insertion or a palpable defect. The addition of MRI increased the explained variance with 7%, 0%, and 7%. The strongest MRI predictor was injury at the bone-tendon junction. Post hoc multiple regression analyses of players without the 2 most important clinical findings were able to explain 24% to 31% of the variance, with no added value of the MRI findings.

CONCLUSION

The strongest predictors of a longer time to RTS after acute adductor injury were palpation pain at the proximal adductor longus insertion, a palpable defect, and/or an injury at the bone-tendon junction on MRI. For athletes without any of these findings, even extensive clinical and MRI examination does not assist considerably in providing a more precise estimate of time to RTS.

Imaging of hip and thigh muscle injury: a pictorial review

Muscle injuries of the hip and thigh are a highly relevant issue in competitive sports imaging. The gold standard in diagnostic imaging of muscle injuries is magnetic resonance imaging (MRI). Radiologists need to be familiar with typical MRI findings in order to accurately detect and classify muscle injuries. Proper interpretation of the findings is crucial, especially in elite athletes. In soccer players, muscle injuries of the hip and thigh are the most common reason for missing a game.The present pictorial review deals with the diagnostic assessment, especially MRI, of muscle injuries of the hip and thigh. Typical MR findings in muscle injuries include edema, hematoma, and tendinous avulsion as well as partial or complete muscle tear. To estimate the time to return to play, a grading into three groups-muscle strain, partial tear, complete tear-has traditionally been used. Taking into account the most recent literature, there are other prognostic factors such as the longitudinal length of a tear, the tendon's intramuscular component, or persisting edema.

Magnetic resonance imaging of muscle injury in elite American football players: Predictors for return to play and performance

Muscle injury accounts for about one-third of total sports-related injuries. The lower limb muscles have one of the highest predisposition for injury in high-level professional athletic sports, such as the National Football League. The commonest group of muscles injured among football players include the hamstrings, followed by the quadriceps. Muscle injuries lead to significant time, off the field and affect return to play. Sports physicians and teams have been keen on assessing such injuries and also relying on multiple tools to safely return the player back to the field. MRI plays a key role in evaluation, follow-up, and assessment for return to play (RTP). In this review, we will discuss details of muscle anatomy, incidence of muscle injuries, injury mechanisms, and use of MRI in assessment, grading, follow-up and in predicting the natural course of muscle injuries in the high-end athletic players. While the use of MRI is clear in diagnosis, and for follow up of muscle injuries, there is some limitation in its ability to predict RTP, based on current MRI classification systems. Footballers who have clinical injuries without MRI evidence of significant muscle injury (grade 0 and 1) have a shorter period of RTP. Injuries classified as high grade (3 and 4) on MRI do not correlate well with time to RTP. Further trials are required to improve the capability of MRI in its prediction of RTP.

Adult thigh muscle injuries-from diagnosis to treatment: what the radiologist should know

Muscle injuries are one of the major problems facing elite athletes, representing a significant source of time lost from competition, with substantial consequences for teams and athletes. There are considerable pressures for a rapid return, but players who return to competition too soon have an increased risk of recurrent muscle injuries, which are associated with longer lay-offs. Imaging plays a key role in achieving the correct diagnosis, and magnetic resonance imaging (MRI) has emerged as the method of choice for skeletal muscle imaging. Several authors have reported prognostic MRI features, but it is difficult to predict the exact length of time to return to full training afterwards due to considerable discrepancy and overlap between different injuries. Therefore, development of a universally applicable classification and grading system is challenging. This paper aims to: (a) review the contemporary role of imaging in the setting of muscle injuries, with special focus on thigh muscles; (b) list the most accepted terminology used to describe muscle injuries;

Central Tendon Injuries of Hamstring Muscles: Case Series of Operative Treatment

Background:

As compared with injuries involving muscle only, those involving the central hamstring tendon have a worse prognosis. Limited information is available regarding the surgical treatment of central tendon injuries of the hamstrings.

Purpose:

To describe the operative treatment and outcomes of central tendon injuries of the hamstrings among athletes.

Study Design:

Case series; Level of evidence, 4.

Methods:

Eight athletes (6 top level, 2 recreational) with central hamstring tendon injuries underwent magnetic resonance imaging and surgical treatment. The indication for surgery was recurrent (n = 6) or acute (n = 2) central hamstring tendon injury. All patients followed the same postoperative rehabilitation protocol, and return to play was monitored.

Results:

Magnetic resonance imaging found a central tendon injury in all 3 hamstring muscles (long head of the biceps femoris, semimembranosus, and semitendinosus) with disrupted tendon ends. In acute and recurrent central tendon injuries, full return to play was achieved at 2.5 to 4 months. There were no adverse events during follow-up.

Conclusion:

Central tendon injuries of the hamstrings can be successfully repaired surgically after acute and recurrent ruptures.

Imaging-detected acute muscle injuries in athletes participating in the Rio de Janeiro 2016 Summer Olympic Games

BACKGROUND

Acute muscle injuries in elite athletes are responsible for a large portion of time loss injuries.

AIM

To describe the frequency, the anatomic distribution, and severity of imaging-detected acute muscle injuries among athletes who competed in the Rio de Janeiro 2016 Summer Olympics.

METHODS

We recorded all sports injuries reported by the National Olympic Committee medical teams and the Organising Committee medical staff during the 2016 Summer Olympics. Imaging of acute muscle injuries was performed at the IOC's polyclinic within the Olympic Village using ultrasound and 3.0 T and 1.5 T MRI scanners. The assessment of images was performed centrally by three musculoskeletal radiologists. The distribution of injuries by anatomic location and sports discipline and the severity of injuries were recorded.

RESULTS

In total, 11 274 athletes from 207 teams were included. A total of 1101 injuries were reported. Central review of radiological images revealed 81 acute muscle injuries in 77 athletes (66% male, mean age: 25.4 years, range 18-38 years). Athletics (track and field) athletes were the most commonly affected (n=39, 48%), followed by football players (n=9, 11%). The majority of injuries affected muscles from lower limbs (n=68, 84%), with the hamstring being the most commonly involved. Most injuries were grade 2 injuries according to the Peetrons classification (n=44, 54%), and we found 18 injuries exhibiting intramuscular tendon involvement on MRI.

CONCLUSION

Imaging-detected acute muscle injuries during the 2016 Summer Olympics affected mainly thigh muscles in athletics disciplines.

Perivascular Adductor Longus muscle injury: Ultrasound and Magnetic Resonance Imaging findings

Background

Muscle injuries affecting the Adductor Longus are not all localised at the level of the proximal myotendinous junction and enthesis. Thus, the main purpose of this article was to raise awareness of the imaging features of the Perivascular Adductor Longus muscle injury, which currently remains widely under-recognised.

Methods

The ultrasound (US) and Magnetic Resonance imaging (MRI) images of five professional football players were retrospectively reassessed to identify distinctive imaging details of the Perivascular Adductor Longus muscle injury. Complementary information regarding the traumatic mechanics is presented as well.

Results

All the players presented similar US images in the first seventy-two hours: loss of ecostructural integrity of the lateral epimysium, in proximity to the femoral vessels, and perilesional oedema were the main pathological findings. The injury lead to the formation of a hypoechoic, intramuscular haematoma in three of the subjects. Anyway, this was detectable only after five days, or later. Moreover, MRI sequences showed long-standing haematoma-related signal alterations which were also observable at three months after trauma. Typically, kicking was the traumatic motor task.

Conclusions

The main practical value of this technical note is to compensate for the lack of studies concerning the Perivascular Adductor Longus muscle injury. Promptly identifying its typical imaging features is crucial in order to establish the correct diagnosis and to implement a highly specific rehabilitative program.

Level of evidence

V.

Imaging of Muscle Injuries in Sports Medicine: Sports Imaging Series

In sports-related muscle injuries, the main goal of the sports medicine physician is to return the athlete to competition-balanced against the need to prevent the injury from worsening or recurring. Prognosis based on the available clinical and imaging information is crucial. Imaging is crucial to confirm and assess the extent of sports-related muscle injuries and may help to guide management, which directly affects the prognosis. This is especially important when the diagnosis or grade of injury is unclear, when recovery is taking longer than expected, and when interventional or surgical management may be necessary. Several imaging techniques are widely available, with ultrasonography and magnetic resonance imaging currently the most frequently applied in sports medicine. This state of the art review will discuss the main imaging modalities for the assessment of sports-related muscle injuries, including advanced imaging techniques, with the focus on the clinical relevance of imaging features of muscle injuries. ^© RSNA, 2017 Online supplemental material is available for this article.

Hamstring Reinjuries Occur at the Same Location and Early After Return to Sport: A Descriptive Study of MRI-Confirmed Reinjuries

BACKGROUND

Despite relatively high reinjury rates after acute hamstring injuries, there is a lack of detailed knowledge about where and when hamstring reinjuries occur, and studies including imaging-confirmed reinjuries are scarce.

PURPOSE

To investigate the location, radiological severity, and timing of reinjuries on magnetic resonance imaging (MRI) compared with the index injury.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A MRI scan was obtained ≤5 days after an acute hamstring index injury in 180 athletes, and time to return to sport (RTS) was registered. Athletes with an MRI-confirmed reinjury in the same leg ≤365 days after RTS were included. Categorical grading and standardized MRI parameters of the index injury and reinjury were scored by a single radiologist (with excellent intraobserver reliability). To determine the location of the reinjury, axial and coronal views of the index injury and reinjury were directly compared on proton density-weighted fat-suppressed images.

RESULTS

In the 19 athletes included with reinjury, 79% of these reinjuries occurred in the same location within the muscle as the index injury. The median time to RTS after the index injury was 19 days (range, 5-37 days; interquartile range [IQR], 15 days). The median time between the index injury and reinjury was 60 days (range, 20-316 days; IQR, 131 days) and the median time between RTS after the index injury and the reinjury was 24 days (range, 4-311 days; IQR, 140 days). More than 50% of reinjuries occurred within 25 days (4 weeks) after RTS from the index injury and 50% occurred within 50 days after the index injury. All reinjuries with more severe radiological grading occurred in the same location as the index injury.

CONCLUSION

The majority of the hamstring reinjuries occurred in the same location as the index injury, early after RTS and with a radiologically greater extent, suggesting incomplete biological and/or functional healing of the index injury. Specific exercise programs focusing on reinjury prevention initiated after RTS from the index injury are highly recommended.

Spanish Consensus Statement: The Treatment of Muscle Tears in Sport

On the 21st of March, 2015, experts met at Clínica CEMTRO in Madrid, Spain, under the patronage of The Spanish Society for Sports Traumatology (SETRADE), The Spanish Federation of Sports Medicine (FEMEDE), The Spanish Association of Medical Services for Football Clubs (AEMEF), and The Spanish Association of Medical Services for Basketball Clubs (AEMB) with the aim of establishing a round table that would allow specialists to consider the most appropriate current general actions to be taken when treating muscle tears in sport, based on proven scientific data described in the medical literature. Each expert received a questionnaire prior to the aforementioned meeting comprising a set of questions concerning therapeutic indications generally applied in the different stages present during muscle repair. The present Consensus Document is the result of the answers to the questionnaire and resulting discussion and consensus over which are the best current indications in the treatment of muscle tears in sport. Avoiding immobilization, not taking nonsteroidal anti-inflammatory drugs (NSAIDs) randomly, fostering early mobilization, increasing vascularization of injured, site and regulating inflammatory mechanisms—without inhibiting these from the early stages of the recovery period—all stood out as main points of the Consensus Document. Additionally, there is controversy concerning cell stimulation techniques and the use of growth factors or cell inhibitors. The decision concerning discharge was unanimous, as was the criteria considered when it came to performing sport techniques without pain.