Differential Diagnosis of Facet Joint Disorders.

Spinal pain due to facet joint disease is difficult to diagnose since the clinical history and physical examination findings are usually nonspecific. Facet joint disorders have a wide range of causes and, because of the potential for chronic back pain and disability, an accurate diagnosis is essential. The most frequent cause of pain in facet joints is osteoarthritis, which can be assessed at radiography, CT, or MRI. Ganglion and synovial cysts of the facet joints can cause compressive symptoms of adjacent structures, especially radiculopathy, lower back pain, and sensory or motor deficits. In ankylosing spondylitis, imaging findings of the facet joints are useful not only for diagnosis but also for monitoring structural changes. In septic arthritis of the facet joints, an early diagnosis at MRI is essential. Gout and metabolic diseases are best evaluated at dual-energy CT, which allows the depiction of crystals. Traumatic dislocations of facet joints are usually unstable injuries that require internal reduction, fixation, and fusion and can be well assessed at CT with three-dimensional reconstructions. Facet joint neoplasms like osteoid osteoma, plasmacytoma, tenosynovial giant cell tumor, and osteochondroma are best evaluated at CT or MRI. The authors provide an overview of key imaging features of the most common facet joint disorders along with anatomic tips and illustrative cases. Acknowledging key imaging findings for the differential diagnosis of facet joint disorders plays a crucial role in the diagnostic accuracy and proper treatment approach for such entities. Online supplemental material is available for this article. ©RSNA, 2021.

Magnetic resonance imaging-based morphological and alignment assessment of the patellofemoral joint and its relationship to proximal patellar tendinopathy.

OBJECTIVE: To assess the differences in morphology and alignment of the knee between patients with proximal patellar tendinopathy (PPT) and a control group, using MRI and focusing on the patellofemoral joint. METHODS: We retrospectively included 35 patients with clinically diagnosed and unequivocal findings of PPT on knee MRI, the case group. For the control group, we included 70 patients who underwent knee MRI for other reasons, with no clinical or MRI evidence of PPT. Patients and controls were matched for age and gender, with all subjects reporting frequent physical activity. MRIs were evaluated by two musculoskeletal radiologists, who assessed parameters of patellar morphology, trochlear morphology, patellofemoral alignment, and tibiofemoral alignment. The differences in parameters between cases and controls were assessed using Student's t test. Logistic regression was applied to assess the associations between the MRI parameters and the presence of PPT. RESULTS: The patellar height Insall-Salvati ratio was different between cases and controls (1.37 ± 0.21 vs. 1.24 ± 0.19; p = 0.003). The subchondral Wiberg angle was higher in cases than controls (136.8 ± 7.4 vs. 131.7 ± 8.8; p = 0.004). After applying logistic regression, significant associations with PPT were found [odds ratios (95% CI)] for patellar morphology [1.1 (1.0, 1.2)] and patellar height [1.3 (1.0, 1.7)]. CONCLUSIONS: Patellar height and the subchondral patellar Wiberg angle were greater in patients with PPT and significantly associated with PPT.

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.

Epidemiology of imaging-detected tendon abnormalities in athletes participating in the Rio de Janeiro 2016 Summer Olympics.

BACKGROUND: Tendon abnormalities are prevalent among both elite and non-elite athletes. Cross-sectional imaging modalities are used to confirm and evaluate the severity of such lesions. AIM: To describe the demographics, prevalence, anatomical location and characteristics of tendon abnormalities in athletes who participated in the Rio de Janeiro 2016 Summer Olympic Games. METHODS: We recorded all sports injuries 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 official IOC clinic within the Olympic Village, using digital ultrasound machines and 3T and 1.5T MR scanners. Image interpretation was performed centrally by board-certified musculoskeletal radiologists with expertise in sports injuries. RESULTS: In total, 11 274 athletes (5089 women (45%), 6185 men (55%)) from 207 NOCs were included. NOC and Rio de Janeiro 2016 medical staff reported 1101 injuries. Central review of radiological images revealed 156 tendon abnormalities in 109 athletes (51.2% male, mean age: 26.8, range 18-39). The supraspinatus tendon was the most commonly involved tendon (31 cases, 19.9%), followed by the Achilles tendon (20 cases, 12.8%) and patellar and infraspinatus tendons (12 cases, 7.7%). Tendon abnormalities were most commonly seen in track and field athletes (54 abnormalities, 34.6%). CONCLUSION: 156 tendon abnormalities were reported, most commonly in track and field athletes, and involving mainly the shoulder tendons, as well as Achilles and patellar tendons.

Second and Third Metatarsophalangeal Plantar Plate Tears: Diagnostic Performance of Direct and Indirect MRI Features Using Surgical Findings as the Reference Standard.

OBJECTIVE: The objective of our study was to assess the diagnostic performance and associations of the direct and indirect MRI features of the metatarsophalangeal (MTP) joint that are thought to be related to tears of the plantar plate (PP) using surgical findings as the reference standard. MATERIALS AND METHODS: We retrospectively included 23 patients with symptomatic instability of lesser MTP joints who had undergone preoperative 1.5-T MRI and surgical assessment. The MRI examinations were independently assessed by two musculoskeletal radiologists. Using the surgical data as the reference standard, we calculated the sensitivity, specificity, and accuracy of each MRI feature in the detection of PP tears. Multivariate logistic regression analysis was performed to identify which MRI features were independently associated with PP tears. Interobserver reliability was assessed using kappa statistics. RESULTS: Forty-five lesser MTP joints were included. The presence of pericapsular fibrosis was highly sensitive (91.2%), specific (90.9%), and accurate (91.1%) for the diagnosis of PP tears. With a cutoff value of 0.275 cm, the PP-proximal phalanx distance had a sensitivity of 64.7%, specificity of 90.9%, and accuracy of 71.1% in diagnosing PP tears. CONCLUSION: In patients with clinical features indicating lesser MTP joint instability, some direct and indirect MRI features exhibited good to excellent diagnostic performance in detecting the presence of PP tears.

Symptomatic Osseous Abnormalities at the Posteromedial Tubercle of the Talus: Magnetic Resonance Imaging Features.

Osseous alterations adjacent to the posteromedial tubercle of the talus that lead to posterior ankle impingement and their imaging findings have been much less well described than alterations of the posterolateral tubercle. We present 5 cases of osseous abnormalities at the posteromedial tubercle of the talus depicted on magnetic resonance imaging in subjects with chronic symptoms at this location, with no history of local trauma, who had presented with posteromedial mechanical pain and/or tarsal tunnel syndrome. The symptoms were related to mechanical changes of the bony and soft tissue structures, leading to posterior impingement, and to neurovascular bundle entrapment at the tarsal tunnel, leading to tarsal tunnel syndrome.

Injury of the gluteal aponeurotic fascia and proximal iliotibial band: anatomy, pathologic conditions, and MR imaging.

The fascia lata, or deep fascia of the thigh, is a complex anatomic structure that has not been emphasized as a potential source of pelvic and hip pain. This structure represents a broad continuum of fibrous tissue about the buttock, hip, and thigh that receives contributions from the posteriorly located aponeurotic fascia covering the gluteus medius muscle and from the more laterally located iliotibial band (ITB). At the pelvis and hip, the ITB consists of three layers that merge at the lower portion of the tensor fasciae latae muscle. The gluteal aponeurotic fascia and ITB merge at the buttock and hip before extending inferiorly to the Gerdy tubercle at the anterolateral tibia. Injuries to these anatomic structures are an underdiagnosed cause of pain and disability and may clinically mimic more common processes affecting the hip and proximal thigh. Categories of disease include overuse injuries, traumatic injuries, degenerative lesions, and inflammatory lesions. Familiarity with the anatomy and pathologic conditions of the fascia lata and its components is important in their recognition as a potential source of symptoms. This article illustrates the anatomy of this complex fascia through anatomic-pathologic correlation and describes the magnetic resonance imaging appearances of the pathologic conditions involving it.

Hamstring Injuries in Professional Soccer Players: Extent of MRI-Detected Edema and the Time to Return to Play.

BACKGROUND: Discrepancies exist in the literature regarding the association of the extent of injuries assessed on magnetic resonance imaging (MRI) with recovery times. HYPOTHESIS: MRI-detected edema in grade 1 hamstring injuries does not affect the return to play (RTP). STUDY DESIGN: Retrospective cohort study. LEVEL OF EVIDENCE: Level 4. METHODS: Grade 1 hamstring injuries from 22 professional soccer players were retrospectively reviewed. The extent of edema-like changes on fluid-sensitive sequences from 1.5-T MRI were evaluated using craniocaudal length, percentage of cross-sectional area, and volume. The time needed to RTP was the outcome. Negative binomial regression analysis tested the measurements of MRI-detected edema-like changes as prognostic factors. RESULTS: The mean craniocaudal length was 7.6 cm (SD, 4.9 cm; range, 0.9-19.1 cm), the mean percentage of cross-sectional area was 23.6% (SD, 20%; range, 4.4%-89.6%), and the mean volume was 33.1 cm3 (SD, 42.6 cm3; range, 1.1-161.3 cm3). The mean time needed to RTP was 13.6 days (SD, 8.9 days; range, 3-32 days). None of the parameters of extent was associated with RTP. CONCLUSION: The extent of MRI edema in hamstring injuries does not have prognostic value. CLINICAL RELEVANCE: Measuring the extent of edema in hamstring injuries using MRI does not add prognostic value in clinical practice.

Imaging techniques for muscle injury in sports medicine and clinical relevance.

Magnetic resonance imaging (MRI) and ultrasound are the imaging modalities of choice to assess muscle injuries in athletes. Most authors consider MRI as the reference standard for evaluation of muscle injuries, since it superiorly depicts the extent of injuries independently of its temporal evolution, and due to the fact that MRI seems to be more sensitive for the detection of minimal injuries. Furthermore, MRI may potentially allow sports medicine physicians to more accurately estimate recovery times of athletes sustaining muscle injuries in the lower limbs, as well as the risk of re-injury. However, based on data available, the specific utility of imaging (including MRI) regarding its prognostic value remains limited and controversial. Although high-quality imaging is systematically performed in professional athletes and data extracted from it may potentially help to plan and guide management of muscle injuries, clinical (and functional) assessment is still the most valuable tool to guide return to competition decisions.