Mixed martial arts (MMA) is a rapidly growing combat sport that combines striking and grappling disciplines including boxing, Muay Thai, karate, judo, and Brazilian jiu-jitsu (BJJ). As participation and professional competition increase, musculoskeletal radiologists become increasingly likely to encounter characteristic MMA-related injuries. Although craniofacial trauma, lacerations, and concussion remain the most common injuries in competition, several distinctive musculoskeletal injury patterns arise from grappling, takedowns, and submission techniques. Understanding the biomechanical forces generated by these manoeuvres contributes to accurate image interpretation and appropriate management. Injuries arising from submission techniques are particularly associated with recognisable imaging patterns. The arm bar most commonly results in ulnar collateral ligament injury at the elbow, whereas the Americana and Kimura shoulder locks may produce anterior and posterior capsulolabral injuries respectively. Heel hooks are associated with rotational knee trauma involving the anterior cruciate ligament and collateral ligaments, with injury patterns varying according to whether valgus-external rotation or varus-internal rotation forces are applied. Less common but highly characteristic injuries include combined lateral collateral ligament and anterolateral ligament injury with intact cruciate ligaments as a result of grappling guard positions and choke manoeuvres. This review summarises the major MMA techniques, associated mechanisms of injury, and key imaging findings relevant to musculoskeletal radiologists.
Peripheral neuropathy in athletes is increasingly recognized as a significant source of morbidity, with injury patterns varying according to the biomechanical demands of specific sports. Although peripheral nerve disorders in athletes may result from acute trauma, they more commonly arise from chronic, repetitive mechanical stress inherent to athletic activity. Despite their frequency, they frequently remain underdiagnosed, as clinical manifestations often overlap with other musculoskeletal disorders. Mechanisms of injury include compression, traction, laceration, ischemia, and repetitive microtrauma. Distinct athletic modalities are associated with characteristic neuropathies reflecting sport-specific kinematics and loading patterns. Awareness of these biomechanical factors and recognition of typical clinical presentations are essential for accurate assessment of athletes with suspected nerve injury. Diagnostic evaluation frequently requires advanced imaging modalities, particularly magnetic resonance neurography (MRN) and high-resolution ultrasound (HRUS), which enable detailed structural assessment of peripheral nerves and detection of secondary imaging findings. Electrodiagnostic studies may provide complementary functional information in selected cases. Early and precise diagnosis is critical to guide management, facilitate safe return to sport, and prevent long-term functional deficits. While most nerve disorders respond to conservative treatment, severe, progressive, or refractory cases may warrant surgical intervention to restore function and enable return to play (RTP). This review examines mechanisms of injury, clinical evaluation, classification systems, imaging findings, and sport-specific patterns of peripheral nerve injury across diverse athletic disciplines.
To evaluate inter-reader agreement and diagnostic accuracy of curved multiplanar reformatting (cMPR) and maximum intensity projection (MIP) techniques for detecting hourglass-like constrictions (HGCs). Thirty brachial plexus 3-Tesla, 3D, 1-mm isotropic MR neurography (MRN) datasets (10 patients without and 20 patients with Parsonage-Turner syndrome (PTS) affecting the suprascapular nerve (SSN)) were retrospectively analyzed by four musculoskeletal radiology fellows for the number and severity of HGCs using both post-processing views in a randomized, blinded fashion. An experienced, attending radiologist served as the reference standard. Inter-reader agreement was assessed using Gwet’s AC1 and intraclass correlation (ICC). Image interpretation time was compared using Wilcoxon signed-rank test. Inter-reader agreement for HGC presence was substantial to almost perfect among fellows (cMPR AC1 = 0.7, MIP AC1 = 0.67) and when compared to the attending (cMPR AC1 = 0.67–0.83, MIP AC1 = 0.63–0.83). Agreement for severe HGC count was substantial to almost perfect (fellows: cMPR ICC = 0.65, MIP ICC = 0.79; vs. attending: ICC = 0.62–0.83, MIP ICC = 0.69–0.88), but poor to fair for mild HGCs (fellows: cMPR ICC = 0.23, MIP ICC = 0.26; vs. attending: ICC = 0–0.21, MIP ICC = 0–0.09). Sensitivity to HGC presence was excellent (cMPR, 85–100
Accurate assessment of osseous morphology is essential for the diagnosis and surgical management of patellofemoral instability. Methods capable of providing CT-like anatomical information while reducing radiation exposure are therefore of considerable clinical interest. This study aimed to validate the accuracy of radiography-derived synthetic computed tomography (sCT) generated by a deep learning model for anatomical assessment of patellofemoral instability. A total of 210 paired radiographs and CT scans were retrospectively collected and randomly divided into a training set (n = 170) and a validation set (n = 40). A deep learning model based on the X2CT-GAN framework was used to reconstruct sCT volumes from anteroposterior and lateral radiographs. Two blinded readers independently measured tibial tubercle-trochlear groove (TT-TG) distance, trochlear sulcus angle, and Caton-Deschamps index on both sCT and real CT images. Reliability, inter-modality agreement, and threshold-based classification agreement were evaluated. All intra- and inter-observer reliability values were excellent. Inter-modality agreement was excellent for TT-TG distance and good for trochlear sulcus angle. Agreement for patellar height was good. The mean absolute error for TT-TG distance ranged from 1.24 to 1.38 mm. Agreement for threshold-based classifications ranged from substantial to almost perfect, with high specificity observed across all evaluated cutoff values. Radiography-derived sCT demonstrated good agreement with real CT for both quantitative measurements and threshold-based classifications relevant to clinical decision-making in patellofemoral instability. These findings suggest that radiography-derived synthetic CT may represent a promising lower-radiation alternative for anatomical assessment of patellofemoral instability in selected clinical scenarios.
Bone deformities are linked to femoroacetabular impingement (FAI) and increased risk of hip osteoarthritis (OA) but are also common in the general population. The purpose of this study is to examine relationships between FAI-linked morphology and resting bone metabolic activity in asymptomatic hips. This exploratory secondary analysis of hip scans from a [18F]NaF PET-MRI study on knee pain included 76 asymptomatic hips from 41 individuals (53 ± 13 years, body mass index 25.9 ± 5.1 kg/m2, 21 female/20 male). Hips were evaluated for cam, pincer, and additional morphology with the Hip Osteoarthritis MRI Scoring System. Mean and maximum PET standardized uptake values (SUV) were recorded for the femoral head-neck junction, center of the femoral head, and anterolateral acetabulum. The influence of morphology on SUVmean and SUVmax was assessed with linear mixed effects models. Forty-two hips had isolated cam morphology, two had isolated pincer morphology, and four had mixed-type morphology. Cam morphology or alpha angles were not associated with increased bone metabolic activity. Hips with gluteal tendinitis/trochanteric bursitis had significantly higher SUVmax in the center of the femoral head (p = 9.98e-5). No other morphological features were associated with bone metabolic activity, though the low prevalence of features such as pincer morphology limits interpretation of these findings. In older asymptomatic hips without OA, no association was detected between cam morphology and elevated resting bone remodeling. Understanding structure–function relationships in asymptomatic hips with cam morphology may help contextualize findings associated with pain in patients with FAI or OA.
