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Abstract Ultrasound guidance is valuable for performing precise joint interventions. Joint interventions may be requested for therapeutic and diagnostic pain injections, joint aspiration in the setting of suspected infection, or contrast injection for arthrography. In practice, interventions of the shoulder girdle, elbow, and hand/wrist joints may be performed without any imaging guidance. However, imaging guidance results in more accurate interventions and better patient outcomes than those performed by palpation alone. When compared to other modalities used for imaging guidance, ultrasound has many potential advantages. Radiologists should be prepared to perform ultrasound-guided upper extremity joint interventions utilizing recommended techniques to optimize clinical practice and patient outcomes. Key points 1. Ultrasound-guided injections of the glenohumeral, acromioclavicular, sternoclavicular, elbow, and hand/wrist joints have higher accuracy than injections performed without imaging guidance. 2. Ultrasound-guided aspirations of upper extremity joints have advantages to fluoroscopic-guided aspirations because of the potential to identify effusions, soft tissue abscess, or bursitis. 3. Ultrasound-guided contrast injection prior to MR arthrography is as accurate as fluoroscopic-guided injection for upper extremity joints.

The ulnar collateral ligament (UCL) supports the medial elbow against valgus torque and is commonly injured in baseball pitchers. Changes in UCL morphology and pathology occur with long-term pitching, with more severe findings at higher competition levels. We examined the bilateral differences and the relationship between UCL morphology, pathology, and ulnohumeral joint laxity in asymptomatic collegiate pitchers using ultrasound.Division I college pitchers (n = 41) underwent ultrasound scans of their bilateral medial elbows, both at rest and in a valgus-stressed position. The presence of enthesopathy, calcifications, and degeneration was assessed qualitatively. UCL thickness and ulnohumeral joint gap were measured with online calipers. The bilateral differences were analyzed using paired t-tests and chi-square analysis, and the relationships between thickness, gapping, and degenerative changes were analyzed using regression analyses.The throwing arm demonstrated greater distal UCL thickness (mean difference (MD) = 0.2 mm (95%CI = 0.1-0.3), p 0.01), resting and stressed gap (MD = 0.3 mm (95%CI = 0.0-0.7), p = 0.04; MD = 0.4 (95%CI = 0.0-0.9), p = 0.02), and greater prevalence of degeneration and enthesopathy (p = 0.03) compared bilaterally. Enthesopathy and calcifications predicted increased distal UCL thickness (p = 0.04; p = 0.02). Degenerative scores predicted increased stressed-resting ulnohumeral joint gap (p 0.01).In the throwing arms of collegiate pitchers, ultrasound demonstrated UCL thickening, enthesopathy/intra-ligamentous calcification, and greater laxity of the ulnohumeral joint relative to the non-throwing arm. Degeneration of the UCL, not thickness, was related to greater elbow joint gapping. This study demonstrates the utility of ultrasound for examining sonographic characteristics of the UCL in a sample of college pitchers.

To characterize the radiographic, CT, and MRI appearance of clinically and/or surgically proven osteochondral lesions of the lateral trochlear ridge. Ten years of medical charts with elbow radiographic, CT, and MRI studies were retrospectively reviewed. Patients with pathology isolated to the lateral trochlear ridge were included. Studies were reviewed by two radiologists. Identifiable pathology on each type of study was noted and characterized. Ten elbow studies were included, all from males aged 15 to 58 years (mean 29 years). Five elbow radiographs were normal, one showed mixed lucency and sclerosis of the lateral trochlear ridge, and four demonstrated small osseous fragments adjacent to the ridge. In all cases, CT demonstrated focal lucency at the cortical surface of the lateral trochlear ridge; 8 contained small osseous fragments, axial plane maximum width ranged from 5 to11 mm, depth from 1 to 2 mm. Focal bone marrow edema in the subchondral lateral trochlear ridge was found in the 6 cases with MR images. Two demonstrated linear high signal underlying the in situ osseous fragment, faintly visible on MRI. In 9 cases, arthroscopy was performed within 3 months of imaging. The remaining patient was treated conservatively with casting. Osteochondral lesions of the lateral trochlear ridge are rare but important, as these patients go on to arthroscopy at a high rate. If an abnormality of the lateral trochlear ridge is seen or suspected, we recommend CT as the best imaging study to define these lesions.

A 9-year-old boy sustained an ulnohumeral dislocation with a medial epicondyle fracture and experienced incomplete post-traumatic median nerve palsy in addition to post-traumatic stiffness following closed reduction and cast immobilization. When his motor palsy and stiffness did not improve, MRI and ultrasound were obtained, which demonstrated entrapment of the median nerve in an osseous tunnel at the fracture site, compatible with type 2 median nerve entrapment. Subsequently, the patient underwent surgery to mobilize the medial epicondyle and free the median nerve, resulting in improved range of motion, near complete restoration of motor function, and complete restoration of sensory function in the median nerve distribution within 6 months of surgery. Median nerve entrapment, particularly intraosseous, is a rare complication of posterior elbow dislocation and medial epicondyle fracture that may result in significant, sometimes irreversible, nerve damage if there is a delay in diagnosis and treatment. A high degree of clinical suspicion with early imaging is indicated in patients with persistent stiffness or nerve deficits following reduction of an elbow dislocation. Intra-articular entrapment diagnosed on ultrasound has been reported and intraosseous entrapment diagnosed clinically and on MR neurography have been reported; however, to our knowledge, this is the first reported case of intraosseous (type 2) median nerve entrapment clearly visualized and diagnosed on traditional MRI and ultrasound. The use of ultrasound for diagnosing median nerve entrapment is an accurate, accessible, and non-invasive imaging option for patients presenting with suspected nerve entrapment following elbow dislocation.

We evaluated magnetic resonance imaging (MRI) findings in patients with clinically diagnosed medial epicondylitis (ME) and determined whether any of the MRI findings correlated with the follow-up pain level after nonoperative treatment.We retrospectively reviewed 83 patients who had undergone elbow MRI examinations for clinically diagnosed ME and who were followed-up for more than 6 months. Five categories of MRI findings were selected for qualitative grading: common flexor tendon (CFT) origin signal changes, ulnar collateral ligament (UCL) insufficiency, ulnar neuritis, bony changes of the medial epicondyle, and calcification. The mean follow-up after MRI examination was 21 months. We performed multivariate regression analysis to analyze whether any of these MRI findings were associated with the follow-up pain level after nonoperative treatment.Positive MRI findings included CFT origin signal changes (66%), ulnar neuritis (40%), UCL insufficiency (30%), calcification (27%), and bony changes (18%). Multivariate analysis indicated that CFT origin signal changes were independently associated with the follow-up pain level (β = 3.387; p = 0.004).In patients with clinically diagnosed ME, MRI demonstrated diverse abnormal findings in the CFT origin, ulnar collateral ligament, ulnar nerve, and bone. Among the findings, the severity CFT origin signal changes, which indicates the severity of tendon degeneration in ME, was associated with the follow-up pain level. This information can be helpful in consulting on the prognosis of nonoperative treatment in patients with clinically diagnosed ME.

Stress fractures of the upper extremities in athletes are important injuries for radiologists to appreciate despite being far less common than stress fractures of the lower extremities. Among upper extremity stress fractures, those involving the olecranon have been well described in overhead pitching athletes. Isolated stress fractures of the ulnar shaft however are less commonly reported in the literature and considered to be rare. We have observed a correlation between young patients with ulnar shaft stress fractures and the activity of fast-pitch softball pitching.In this series, we present the imaging findings in four cases of ulnar shaft stress fractures in softball pitchers who presented with insidious onset forearm pain. Furthermore, a review of the literature focusing on softball pitching mechanics is provided to offer a potential underlying mechanism for the occurrence and location of these injuries.An awareness of the imaging appearance of ulnar shaft stress fractures along with an understanding of its proposed mechanism will facilitate accurate and timely imaging diagnosis of this injury by the radiologist.

To describe the technique of sonographic ulnar nerve mapping in the postoperative elbow for surgical planning.A retrospective review of a surgical databank identified 24 patients, all aged 18 years and older with a history of orthopedic elbow surgery, who were referred for preoperative sonographic mapping of the ulnar nerve prior to subsequent surgery. All cases were reviewed for patient demographics, clinical presentation, prior surgical interventions, and ultrasound technique. Charts were reviewed for intraoperative and postoperative outcomes, including nerve injury.The cohort included 12 males and 12 females with a mean age of 51 years (range 22-68 years) and a mean BMI of 29 (range 20-48). Preoperative sonographic ulnar nerve mapping occurred following various elbow surgeries including ulnar nerve transposition to assess nerve location prior to subsequent elbow surgery. Of the 24 patients with preoperative sonographic ulnar nerve mapping, subsequent surgery was performed arthroscopically in 14 and open in 10 cases. In 11 of the 24 cases, there was specific mention of a modified approach to joint access which was guided by the ulnar nerve map. There were no perioperative ulnar nerve-related complications, such as nerve transection.Preoperative mapping can facilitate planning of surgical access and ulnar nerve dissection. Sonographic mapping of the ulnar nerve reduces the potential uncertainty of nerve palpation in a complex postoperative elbow following ulnar nerve transposition. This technique may mitigate the risk of ulnar nerve injury.

To establish a high-resolution US technique that enables a systematic morphometric examination of the three components that form the distal biceps brachii tendinous complex; the internal bicipital aponeurosis, the distal biceps brachii tendon and the external bicipital aponeurosis (also known as lacertus fibrosus). Fifty cryopreserved cadaver body donor elbows were dissected to obtain morphometric reference values and to establish reliable landmarks for the US examination. Then, a systematic US technique was designed and validated by a one-to-one US/dissection analysis of 11 cryopreserved cadaver body donor elbows. Finally, the systematic US technique was carried out in 44 healthy volunteers and morphometric parameters were compared to those obtained in the first part of the study. Mean dissection reference values: internal bicipital aponeurosis width 39.61 mm (10.02 SD) and thickness 0.75 mm (0.24 SD), distal biceps brachii tendon width 8.38 mm (1.87 SD) and thickness 2.73 mm (0.69 SD), external bicipital aponeurosis width 11.17 mm (5.84 SD) and thickness 0.85 mm (0.28 SD). One-to-one US/dissection correlation was overall good (intraclass correlation coefficient 0.876, p

Although bicipitoradial bursitis is not commonly seen, when it does occur, it can frequently lead to diagnostic difficulty, mimicking either a soft-tissue tumor or infection. Lack of awareness of this uncommon entity can lead to unnecessary anxiety or tissue biopsy. This pictorial essay discusses the normal anatomy of the bicipitoradial bursa and the spectrum of imaging findings of bicipital bursitis.

Multimodality elbow screening of adolescent baseball players shows apparent laterality in morphology and signal intensity of the medial epicondyle on dedicated magnetic resonance imaging. We aimed to elucidate actual imaging laterality in the medial epicondyle by comparing magnetic resonance images of the dominant and contradominant elbows and to clarify the clinical meaning and mechanism of this phenomenon. We used a 0.2-T dedicated magnetic resonance imaging scanner. Eighty adolescent baseball players were enrolled and divided into four age groups: 9–10 years (13 patients); 11 years (28 patients); 12 years (24 patients) and 13–14 years (15 patients). The long and short axes of the ossification center and distance of the epiphyseal plate and the cartilage of the lower pole of the medial epicondyle were measured. Signal intensity of the ossification center was visually evaluated. Owing to their age, ossification and cartilage size on the dominant side were significantly larger in all boys (P

Lipoma arborescens is a rare non-neoplastic condition that affects the synovial lining of joints and bursae accounting for less than 1% of all lipomatous lesions. Characterized by villous proliferation of the synovium, it is an uncommon cause of intra/periarticular mass presenting as a painless, slowly progressive longstanding swelling, and is sometimes accompanied by intermittent monoarticular effusions. We describe a rare case of bilateral lipoma arborescens in the bicipitoradial bursae in a young male referred for MRI evaluation of spontaneous bilateral elbow swelling. We chose to bring this case to light because of the rare simultaneous involvement of the bicipitoradial bursae bilaterally and the role of MR in providing a definite diagnosis, hence obviating the need for biopsy and avoiding consideration of other complex intra/periarticular masses.

To determine the prevalence of intra-articular gas (IAG) on elbow radiography and evaluate variables, including IAG, as predictors of UCL injury. This IRB-approved retrospective study consisted of 241 consecutive elbow radiographic studies containing AP radiographs with valgus stress of both symptomatic and asymptomatic sides in 234 patients. The IAG, medial joint space (MJS), and MJS difference between the symptomatic and asymptomatic elbow (MJSD) were evaluated by two readers, as well as patient age, gender, sport played, and handedness. Primary outcomes included IAG on valgus stress radiographs and UCL injury, which was determined by intraoperative findings as the reference standard or MRI if surgery was not performed. Univariate analysis with Student’s t, Fisher’s exact, and chi-square tests were performed. IAG only manifested with valgus stress and was demonstrated in 30/482 (6.2%) valgus stress radiographs in 27/234 (11.5%) patients. Overall, 21/241 (8.7%) valgus stress radiographs of the symptomatic elbow demonstrated IAG in 21 patients. A total of 128/241 (53.1%) elbow studies had evidence of UCL injury. MJS IAG (p = 0.0147) and increased MJSD (p = 0.0088) were significantly associated with UCL injury. Patient gender, age, handedness, laterality, sport played, and absolute MJS were not associated with UCL injury. MJS IAG with valgus stress demonstrates a sensitivity of 11.7% and specificity of 98.3% in detecting UCL injury for the symptomatic elbow. MJS IAG infrequently manifests on valgus stress radiographs, but is specific for UCL injury in the symptomatic elbow of overhead throwing athletes. MJS IAG and increased MJSD are significantly associated with UCL injury.

The Essex-Lopresti injury is an extremely rare condition combining radial head or neck fracture, distal radio-ulnar joint dislocation and rupture of the interosseous membrane. However, there are rare or unusual varieties or associated injuries. We report a case of a 46-year-old woman with a posterior dislocation of the radio-humeral joint, a radial shaft fracture, and a distal radio-ulnar joint dislocation. She underwent open reduction and internal fixation of the radial shaft fracture followed by an immobilization by a long elbow splint in supination for 6 weeks. At 18 months of follow-up, she was asymptomatic and she had a full range of elbow and wrist motion and had resumed thoroughly her previous job. The Essex-Lopresti injury results from a complex injury to the forearm axis with resultant longitudinal instability, which can be challenging to treat. There are some variations that can lead to a missed diagnosis resulting in persistent pain and instability of the wrist. The best outcomes are reached with early diagnosis and prompt management.

The ulnar collateral ligament (UCL) is an important medial stabilizer of the elbow, particularly in overhead-throwing athletes. However, there is no universally accepted method for evaluating UCL thickness with ultrasound (US). To assess reproducibility of previously published methods, as well as a modified technique, for evaluating the UCL via US. We hypothesize that a modified technique would show greater reproducibility. Using US, the thickness of the UCL in 50 volunteers was measured by two musculoskeletal trained radiologists using two different measurement techniques. The techniques utilized were as described by Nazarian and Jacobson/Ward (JW). Technique measurements were evaluated using interclass correlation coefficients (ICC) to determine the reproducibility of each method. Twenty-eight of the subjects also underwent measurement via a modified JW technique, measured perpendicular to the ligament rather than the frame of imaging. This technique was also evaluated with ICC values. The ICC value for the Nazarian technique was 0.82 (very good) and 0.51 (moderate) for the JW technique. When using the modified JW technique, we found an ICC value of 0.84 (very good). Mean ligament thickness was greatest with the Nazarian technique, 6.41 mm, with the JW technique measuring 1.86 mm and the modified technique measuring 1.38 mm. US assessment of UCL thickness by all three measurement techniques are reproducible. The JW technique had less interobserver agreement when compared to the Nazarian method, whereas the modified JW technique had greater reproducibility compared to the JW technique and similar to the Nazarian technique.

The overhead-throwing athlete is susceptible to a variety of predictable disease entities affecting the shoulder and elbow. While the pathophysiology and nomenclature of these diseases are ubiquitous throughout the clinical literature, this information is sparse within the radiology domain. We provide a comprehensive review of these unique injuries with accompanying imaging features in an effort to enhance the role of the radiologist during the management of the overhead thrower. When appropriately recognized and described, the imaging features aid in establishing a diagnosis and ultimately the implementation of appropriate clinical management.

Distal biceps brachii tendon (DBBT) rupture is an uncommon but functionally significant injury given the loss of supination, flexion strength and pain that often result. Prompt surgical repair is preferred in most patients. Clinicoradiological post-operative follow-up is typically performed to assess DBBT repair integrity and function, frequently using ultrasound, though to date, no studies have described post-operative DBBT repair sonographic appearances. The purpose of this study was to evaluate post-operative DBBT sonographic appearances in the context of Endobutton repair with the following aims:i.Establish typical ultrasound appearances 12 months post-surgeryii.Establish the relationship between ultrasound appearances and clinical/functional outcomes.Sixty patients between February 2016 and October 2017 undergoing DBBT repair were prospectively recruited, all undergoing clinical and sonographic assessment 12 months post-surgery. Ultrasound data was collected on tendon integrity, tendon calibre and presence of intratendinous calcification, peritendinous fluid and peritendinous soft tissue/scarring. Clinical data was collected on active range of motion (ROM) (flexion, extension, supination, pronation) and strength (flexion and supination).A total of 57/60 patients had intact DBBT repairs identified sonographically and clinically at 12 months. DBBT repairs had significantly increased cross-sectional area (mean 260%, 95% CI: 217%, 303%) compared with non-operated DBBT. Ninety-three percent of DBBT repairs were hypoechoic. Thirty percent contained intratendinous calcification. Peritendinous fluid/soft tissue was rarely observed. There was no significant correlation between DBBT calibre and strength/ROM parameters.Normal post-operative sonographic appearances of Endobutton DBBT repair comprise a hypoechoic tendon significantly increased in calibre compared with non-operated tendon ± intratendinous calcification. DBBT repair calibre varies greatly, but is not associated with any significant difference in strength/ROM.

Ulnar collateral ligament (UCL) reconstruction is now being performed more commonly and on younger patients than in prior decades. As a result, radiologists will increasingly be asked to evaluate elbow imaging of patients presenting with pain who have had UCL reconstruction. It is essential for radiologists to understand the normal and abnormal imaging appearances after UCL reconstruction and ulnar nerve transposition, which is also commonly performed in overhead-throwing athletes. Doing so will allow radiologists to provide accurate interpretations that appropriately guide patient management.

Elbow screening of adolescent baseball players began in 2014 using ultrasound, palpation, and dedicated magnetic resonance imaging (MRI). We frequently encountered subjects showing MCL injury on MRI but no clinical symptoms. We assessed variations in asymptomatic MCL injury findings at follow-up MRI, and clarified the pathogenesis of these findings. Using a 0.2-T-dedicated MRI, 30 subjects with asymptomatic MCL injury at initial MRI who agreed to follow-up MRI were included. We classified the findings at repeat MRI as follows: (a) disappeared, (b) better, and (c) worse. There were 6, 16, and 8 subjects in groups a, b, and c, respectively. The average age at follow-up was 14.0, 12.1, and 12.4 years in groups a, b, and c, respectively. There were significant differences between groups a and b and between groups a and c. Average height at follow-up of groups a, b, and c was 1.64, 1.52, and 1.57 cm, respectively, with a statistically significant difference between groups a and b. The average size of the short axis of the MCL of subjects in group a was 2.0 cm on the dominant side and 1.5 cm on the contradominant side (P

"Buttonholing" of the radial head through the anterior joint capsule is a known cause of irreducible anterior radial head dislocation associated with Monteggia injuries in pediatric patients. To the best of our knowledge, no report has described an injury consisting of buttonholing of the radial head through the annular ligament and a simultaneous radial head fracture in an adolescent. In the present case, the radiographic findings were a radial head fracture with anterior dislocation and lack of the anterior fat pad sign. Magnetic resonance imaging (MRI) clearly demonstrated anterior dislocation of the fractured radial head through the torn annular ligament. The anterior joint capsule and proximal portion of the annular ligament were interposed between the radial head and capitellum, preventing closed reduction of the radial head. Familiarity with this condition and imaging findings will aid clinicians to make a proper diagnosis and fast decision to perform an open reduction.

Fracture of the humeral medial epicondyle is a relatively common injury in children. Surgery is a good option for treatment, but correct diagnosis is important. Most fractures occur after the ossification of the medial epicondylar apophysis. If a fracture occurs before the ossification of the medial epicondyle, it is undetectable by radiographs. Here we report a case of an unossified medial epicondyle fracture of the humerus. A 9-year-old boy had persistent pain in the medial side of the right elbow after a fall. Despite his pain, he could move his injured elbow with a range from 60 to 90°. Radiographs and computed tomography showed neither fracture nor dislocation in the injured elbow, and soft tissue swelling was the only finding. Neither the trochlea nor the medial epicondyle was ossified. Magnetic resonance imaging showed that the medial epicondyle was separated from the medial metaphysis and displaced. This clear finding led us to surgical fixation. Under general anesthesia, valgus stress showed gross instability of the injured elbow. Two years after the operation, he had no complaints and could play sports with the same range of motion as the left elbow. It is important to keep in mind that medial epicondylar fractures may be hidden in a normal radiograph before the ossification of the medial epicondylar apophysis.

Objectives were to study the MRI appearance of the repaired distal biceps tendon (DBT), anatomically reinserted, and to search for a correlation between tendon measurements and functional results.Twenty-five patients (mean age, 49 ± 4.9 years old) who benefited from 3-T MRI follow-up of the elbow after surgical reinsertion of the DBT were retrospectively included and compared to a control group (n = 25; mean age, 48 ± 10 years old). MRI was performed during the month of clinical follow-up and on average 22 months after surgery. Delayed complications (secondary avulsion, new rupture), intratendinous osteoma, tendinous signal on T1-weighted (T1w) and fat-suppressed proton density-weighted (FS-PDw) images as well as DBT measurements were recorded. The maximum isometric elbow flexion strength (MEFS) and range of motion of the elbow were assessed.Repaired DBT demonstrated a heterogeneous but normally fibrillar structure. Its low T1w signal was less pronounced than that of normal tendons, and the FS-PDW image signal was similar to that of T1w images. MRI detected seven osteomas (Se = 53 % vs. plain radiography), one textiloma and one secondary avulsion. Repaired DBT measurements were significantly correlated with MEFS (dominant arm R2: 0.38; nondominant arm R2: 0.54); this correlation involved the insertion surface (Δ = -75.7 mm(2), p = 0.046), transverse diameter (Δ = -2.6 mm, p = 0.018), anteroposterior diameter at the level of the radial head (Δ = -3.9 mm, p = 0.001) and DBT cross-sectional area (Δ = -50.2 mm(2), p = 0.003).The quality of functional outcome after anatomical elbow rehabilitation of DBT correlates with the extent of tendinous hypertrophy during the healing process.

To determine whether subchondral surface irregularities of the capitellum on ultrasonography in baseball players under the age of 10 years are indicative of early osteochondritis dissecans (OCD) of the capitellum. A total of 321 players aged 6–9 years underwent ultrasonographic examination, and the findings for the subchondral bone of the capitellum on the throwing side were graded as 0, 1a, 1b, 2, or 3. Subjects classified as grade 1a or 1b showed irregularities of the subchondral bone surface and were investigated radiographically for OCD. All players continued to throw and were re-examined by ultrasonography after 1 and 2 years. At the first examination, 11/321 (3.4%) had irregularities at the subchondral surface of the capitellum [grade 1a in 7/321 (2.2%); grade 1b in 4/321 (1.2%)]. The seven players with grade 1a showed no evidence of OCD or Panner’s disease on radiography and were reclassified as grade 0 at the 2-year follow-up. All four players with grade 1b were reclassified as grade 0 at follow-up 1 and 2 years later. Subchondral bone surface irregularities of the capitellum on ultrasonography in children under the age of 10 years may not be indicative of disease, but rather represent variation of ossification during normal development.

Chondromyxoid fibroma (CMF) is a rare benign cartilage congener tumor comprising less than 1 % of primary bone tumors. Although the age range is wide, it is most commonly seen in the second and third decades. The most frequent location of CMF is in the long tubular bones of the lower extremities, particularly the proximal tibia and distal femur. Although the majority of chondromyxoid fibromas present as intramedullary tumors, a subgroup of chondromyxoid fibromas arising as surface lesions of the bone has recently been described. These are associated with an older mean age and an increased incidence of matrix calcifications. Chondromyxoid fibromas are rare in the distal ulna. We report a CMF presenting as a surface lesion of the distal metaphysis of the left ulna in a 41-year-old woman. We reviewed the literature on chondromyxoid fibromas involving the ulna and found that out of 22 cases, 1 was in the distal ulna, 13 in the proximal ulna, and in the remaining 8 the ulnar sites were unspecified. No case of chondromyxoid fibroma in the published literature had been designated as a surface lesion. Our own unpublished data include 70 chondromyxoid fibromas, 4 of which are in the ulna. Two of these are in the distal portion.

To identify the incidence of brachialis enhancement deficits (BEDs) on contrast-enhanced elbow MRIs and determine if there is an association between the presence of BEDs and presenting symptoms, other imaging findings, or patient positioning.Elbow MRIs from 138 patients (64 males, mean age 45.3 years) were reviewed. The presence, size, and degree of enhancement of BEDs as well as degree of elbow flexion, relative degree of forearm rotation, and additional finding of pathology on the MRI were recorded.BEDs were found in 54 % (75/138) of contrast-enhanced elbow MRIs. No statistically significant difference was seen between age, gender, presenting symptoms and the presence of BEDs. The BEDs varied considerably in size and degree of diminished enhancement compared to adjacent muscle. There was a very significant correlation between degree of elbow flexion and presence of BEDs (p 0.0001) and a significant inverse correlation between cross-sectional size of BEDs and degree of flexion (p 0.01). There was no significant correlation between BED enhancement difference and degree of flexion and no significant correlation between degree of forearm rotation and cross-sectional area or enhancement difference of the BEDs. No correlation was found between the presence of BEDs and other pathology present on the MRI.BEDs are a common, likely asymptomatic phenomenon seen on post contrast elbow MRIs. The etiology of BEDs is uncertain, but they may represent a vascular phenomenon related to elbow flexion causing diminished enhancement related to brachialis compression.

To describe imaging findings in patients with synovial fringe (SF) syndrome of the elbow and to compare with a control population.Nine patients (5 men, 4 women) whose mean age was 35.7 years were diagnosed with SF syndrome and had undergone preoperative elbow MRI. The radiohumeral (RH) plica was assessed for thickness, cross-sectional area, coverage of one third or more of the radial head, blunting of the free edge, and T2 signal intensity abnormality. Other abnormalities of the RH joint were also assessed, including adjacent articular cartilage defects, subcortical bone marrow signal abnormality in the capitellum, and synovitis. Results were compared with 15 control patients who were asymptomatic laterally and posteriorly.Mean thickness and cross-sectional area of the RH plica were 1.8 mm and 19.4 mm(2) respectively in controls, compared with 2.5 mm and 21.9 mm(2) respectively in symptomatic patients. No statistically significant differences in the distribution of the mean thickness or cross-sectional area of the RH plica were found between the two groups. However, 67% of SF syndrome patients had a RH plica thickness greater than 2.6 mm compared with only 13% of controls (p = 0.021). Other abnormalities of the RH plica occurred more frequently in patients with SF syndrome compared with controls, but were not statistically significant.In patients presenting with posterolateral pain or mechanical symptoms in the elbow, RH plica thickness greater than 2.6 mm on elbow MRI examinations may help identify patients with SF syndrome.

Brachialis periosteal avulsion injury is an uncommon injury occurring in young children. The injury may be misinterpreted or overlooked because of misleading or subtle radiological findings. A case of 7-year-old child with post-traumatic elbow pain and subtle findings on elbow radiography is presented. The injury was initially misinterpreted as an avulsion fracture of the medial epicondyle. Following radiological review, a diagnosis of brachialis periosteal avulsion injury was made. The radiographic and magnetic resonance imaging (MRI) findings of this injury are presented to stress the value of comparing the radiographic findings with previous imaging and to increase awareness of this uncommon injury.

The diagnosis of lateral epicondylitis is often straightforward and can be made on the basis of clinical findings. However, radiological assessment is valuable where the clinical picture is less clear or where symptoms are refractory to treatment. Demographics, aspects of clinical history, or certain physical signs may suggest an alternate diagnosis. Knowledge of the typical clinical presentation and imaging findings of lateral epicondylitis, in addition to other potential causes of lateral elbow pain, is necessary. These include entrapment of the posterior interosseous and lateral antebrachial cutaneous nerves, posterolateral rotatory instability, posterolateral plica syndrome, Panner's disease, osteochondritis dissecans of the capitellum, radiocapitellar overload syndrome, occult fractures and chondral-osseous impaction injuries, and radiocapitellar arthritis. Knowledge of these potential masquerades of lateral epicondylitis and their characteristic clinical and imaging features is essential for accurate diagnosis. The goal of this review is to provide an approach to the imaging of lateral elbow pain, discussing the relevant anatomy, various causes, and discriminating factors, which will allow for an accurate diagnosis.

Triceps tendon injuries are reported to be very rare. To our knowledge, there have been no studies describing its prevalence or injury patterns on MR imaging. The purpose of this retrospective study was to determine the prevalence and patterns of triceps injuries based on a large series of consecutive MR examinations. Clinical correlation was obtained.From 801 consecutive elbow MR examinations over a 15-year period, 28 patients with 30 triceps tendon injuries were identified and graded as partial tendon tear and complete tendon tear. The patients' medical records were reviewed to determine age, gender, cause of tears, and management.The prevalence of triceps tendon injuries was 3.8%. There were 5 women and 23 men with partial or complete tears (mean age: 46.6 years; range: 2.7 to 75.1 years). The most common injury was partial tear, found in 18 patients. There were 10 patients with 12 complete tears (2 had re-torn following surgical repair). A tear was suspected in 12 out 28 (43%) patients prior to the MRI. The most common presenting symptom was pain. The most common cause was athletic injury (8 patients [29%], including weightlifting [2 patients]). Tendon tear was found to be a complication of infection in 6 patients, and in 3 patients the tears were a complication of steroid use. Thirteen tendon tears were surgically repaired (8 of these were complete tears).Triceps tendon injury is not as rare as commonly reported and may often be clinically underdiagnosed.

Objective: To describe osseous landmarks that allow identification of the attachments of the ligaments and tendons in the distal medial aspect of the humerus. Materials and methods: Reliable osseous landmarks in the distal medial aspect of the humerus were identified in 34 well-preserved specimens from a paleopathologic collection. These osseous landmarks were then sought in magnetic resonance (MR) images of ten cadaveric elbow specimens so that the ease of their visualization and optimal imaging plane could be assessed. To assign these osseous landmarks to specific attachments of the tendons and ligaments in the distal medial humerus, we cut the specimens in slices and photographed and examined them. Subsequently, the prevalence of these osseous landmarks as well as the attachment sites of the tendons and ligaments in this location was determined. Results: We determined ten reliable osseous landmarks in the distal medial aspect of the humerus, their prevalence and ease of identification, and their relationship to the attachments of the tendons and ligaments at the medial distal humerus. Conclusion: It is possible to use osseous landmarks at the distal medial humerus to facilitate identification of the different attachments of tendons and ligaments when MR images of the elbow are assessed

To evaluate the technical feasibility of performing elbow MR arthrography via a posterior approach through the triceps.The images of 19 patients with elbow MR arthrography via a posterior transtriceps approach were retrospectively studied. The injections were performed by four musculoskeletal radiologists, using fluoroscopic guidance and a 22- or 25-gauge needle. The fluoroscopic and subsequent MR images were reviewed by two musculoskeletal radiologists and evaluated for adequacy of joint capsular distention, degree and location of contrast leakage, and presence of gas bubbles.The injection was diagnostic in all 19 patients, with a sufficient amount of contrast agent seen in the elbow joint. No significant contrast leakage occurred in 12 patients who received injections of 8 cc or less of contrast agent, but moderate contrast leakage occurred in 6/7 patients who received injections of greater than 8 cc. Contrast leakage generally occurred within the triceps myotendinous junction. No gas bubbles were identified in the injected joints.Patients often present for MR arthrography of the elbow with medial or lateral elbow pain. Contrast leakage during a radiocapitellar approach may complicate evaluation of the lateral collateral ligament or the common extensor tendon origin. Transtriceps MR arthrography offers an alternative to the more commonly used radiocapitellar approach. With injected volumes not exceeding 8 cc, the risk of significant contrast leakage is small. An advantage of the transtriceps injection is that contrast leakage through the posterior needle tract does not interfere with evaluation of the lateral structures.

The purpose of this study was to provide a detailed description of the anatomy of the coronoid process of the ulna and to use magnetic resonance (MR) images and anatomic correlation with cadavers to show the macroscopic configuration of this structure. Photography and high-resolution radiography were performed in 26 ulna specimens from the collection of a local museum. MR imaging of the coronoid process of 11 cadaveric elbows was performed. The images were compared with those seen on anatomic sectioning. The anteromedial rim of the coronoid process of the ulna had a regular surface, without osseous irregularities or facets in 69.2% of the specimens. In 30.8% of the specimens, the anteromedial rim was not regular and a small ridge could be identified. The insertion site of the joint capsule was onto the anterior aspect of the coronoid process, at an average distance of 5.9 mm distal to the tip. The attachment of the anterior band of the ulnar collateral ligament at the sublime tubercle was flush with the articular margin in 63.6% of the specimens. In 36.4% of the specimens, a more distal attachment, with a separation between the undersurface of the ligament and the adjacent tubercle, was seen. The brachialis tendon was attached to the coronoid process at a mean distance of 12.1 mm distal to the tip. The coronoid process of the ulna is a small osseous structure with a complex anatomy and presents some anatomical variations.

It has been proposed that the defining difference between rheumatoid arthritis and spondyloarthropathy (including psoriatic arthritis) is the initial pathological lesion where the emphasis in psoriatic arthritis is on the enthesis and in rheumatoid arthritis on the synovium. Classical radiological descriptions of seronegative spondyloarthropathy include enthesopathy at major entheseal insertions characterised by erosions and exuberant new bone formation. In this study, the plain radiographic features of spondyloarthropathy are compared between psoriatic arthritis, other spondyloarthropathies and rheumatoid arthritis. The CASPAR study collected clinical, radiological and laboratory data on 588 patients with physician diagnosed psoriatic arthritis and 525 controls with other inflammatory arthritis, 70% of which had rheumatoid arthritis. Plain radiographs of the pelvis and heels were part of the study protocol, although radiographs of other potential entheseal sites such as the knee, elbow and shoulder, were interpreted if available. All radiographs were read blind by two observers working in tandem. Significant differences in entheseal erosion and entheseal new bone formation were found between psoriatic arthritis, ankylosing spondylitis, undifferentiated spondyloarthropathy, rheumatoid arthritis and other diagnoses (entheseal erosion, chi-squared 20.8, p = 0.008; entheseal new bone formation, chi-squared 24.5, p = 0.001). These differences were mainly due to a higher proportion of these features in ankylosing spondylitis. No differences in the plain radiographic features of enthesopathy were found between psoriatic arthritis and rheumatoid arthritis except in the case of entheseal new bone formation at sites of attachment of inguinal ligament, sartorius and rectus femoris muscles to the ilium (OR 3.01, 95% CI 1.13–8.02). Very few subjects with symptomatic heel involvement had radiographic changes and minimal differences were found between those with and without symptoms in terms of new bone formation and erosion at either calcaneal site. New bone formation and erosion at major entheseal sites is most commonly seen in ankylosing spondylitis. Plain radiographic features of major enthesopathy are poor discriminators between psoriatic arthritis and rheumatoid arthritis.

Baseball pitcher throwing biomechanics are important to understanding the pathophysiology and magnetic resonance (MR) imaging appearances of injuries in baseball pitchers. Baseball pitchers experience repetitive excessive valgus forces at the elbow. Typical injuries are secondary to medial joint distraction, lateral joint compression, and rotatory forces at the olecranon. MR imaging is useful for evaluation of the elbow in baseball pitchers.

Carpal-tarsal osteolysis is a rare condition that manifests as the progressive resorption of carpal and tarsal bones in young children. The diagnosis of this condition is often difficult and delayed as the initial clinical presentation is non-specific. Radiographic changes occur gradually, are often not seen at presentation and depend on recognising loss of bone in the ossification centres of the carpus and tarsus. MRI demonstrates morphological abnormalities in the cartilaginous, as well as the osseous components, of the developing carpal and tarsal bones and therefore may be helpful in predating the radiographic changes. Ultrasound appears to contribute little to the diagnosis and may be misleading. Exclusion of other conditions, particularly juvenile idiopathic arthritis, is important in making the diagnosis. MRI can be useful in excluding an inflammatory arthropathy, and suggesting the diagnosis of carpal-tarsal osteolysis.

An 76-year-old man with an indolent soft tissue mass on the volar aspect of the left elbow was referred to our institution with a diagnosis of a soft tissue tumor. He had a history of lung tuberculosis since the age of 30. The mass was adjacent to the biceps brachi tendon. It demonstrated homogeneous low-signal intensity on T1-weighted magnetic resonance (MR) images and heterogeneous relatively high signal intensity with scattered low and high signal intensity areas on T2-weighted MR images. An excision was performed after needle biopsy with presumptive diagnosis of bicipitoradial bursitis. The histological specimen revealed an epithelioid cell granuloma with central necrosis. While the occurrence of tuberculous bicipitoradial bursitis has never been reported, this case demonstrates that it can be considered to be among the causes of a cystic lesion around the elbow joint.

Supracondylar humerus fractures (SCHF) are common in the pediatric population. Cubitus varus deformity (CVD) is the most common long-term complication of SCHFs and may lead to elbow instability and deficits in throwing or extension. Distal fragment malrotation in the axial plane disposes to fragment tilt and CVD; however, no simple method of assessing fracture malrotation exists. This study tested a mathematical method of measuring axial plane malrotation in SCHFs based on plain radiographs. A pediatric SCHF model was made, and x-rays were taken at known intervals of rotation. Five independent, blinded observers measured these films. Calculated rotation for each data set was compared to the known rotation. The identical protocol was performed for an aluminum phantom. The reliability and agreement of the rotation values were good for both models. This method is a reliable, accurate, and cost-effective means of calculating SCHF distal fragment malrotation and warrants clinical application.

Painful snapping of the elbows is rare. We report on a 12-year-old boy with a painful snap in both elbows. High-resolution magnetic resonance imaging of the elbow using microscopy coils detected a synovial fold interposed in each humeroradial joint and was very helpful in establishing the cause of symptoms. Resection of the synovial folds was performed with subsequent relief of symptoms.

This study was performed to determine the ability of a routine radiographic examination of the elbow to detect osteochondritis dissecans of the capitellum and associated intra-articular loose bodies. The study group consisted of 15 patients with osteochondritis dissecans of the capitellum confirmed by surgery or magnetic resonance imaging. Seven of the 15 patients had associated intra-articular loose bodies confirmed by surgery. All 15 patients had anteroposterior and lateral radiographs and magnetic resonance imaging of their symptomatic elbow. Nine of the 15 patients had subsequent elbow surgery. We reviewed the original interpretations of the radiographic examinations of the elbow of all 15 patients to determine whether osteochondritis dissecans of the capitellum and associated intra-articular loose bodies had been identified prospectively. We also reviewed the elbow radiographs of all 15 patients to determine whether osteochondritis dissecans of the capitellum and associated intra-articular loose bodies could be identified retrospectively. Osteochondritis dissecans of the capitellum was detected during the initial interpretations of the radiographic examinations of the elbow in seven of 15 patients. Osteochondritis dissecans of the capitellum was detected during retrospective review of the elbow radiographs in 10 of 15 patients. Intra-articular loose bodies were detected during the initial interpretations of the radiographic examinations of the elbow in three of seven patients. Intra-articular loose bodies were detected during retrospective review of the elbow radiographs in four of seven patients. A routine radiographic examination of the elbow has limited sensitivity for detecting osteochondritis dissecans of the capitellum and associated intra-articular loose bodies.

To compare the MR imaging findings of 13 patients with clinically diagnosed medial epicondylitis with the MR imaging findings of 26 patients of similar age with no clinical evidence of medial epicondylitis. The study group consisted of 13 patients with clinically diagnosed medial epicondylitis. The control group consisted of 26 patients of similar age with no clinical evidence of medial epicondylitis. The medical records and MR imaging findings of these patients were retrospectively reviewed by two fellowship-trained musculoskeletal radiologists. Eleven of the 13 patients in the study group had thickening and increased signal intensity of the common flexor tendon on both T1-weighted and T2-weighted images. The remaining two patients in the study group had soft tissue edema around a normal-appearing common flexor tendon. Twenty-one of the 26 patients in the control group had a normal-appearing common flexor tendon on MR imaging. Three patients in the control group had a thickened common flexor tendon which was of intermediate signal intensity on T1-weighted images but of uniform low signal intensity on T2-weighted images. Two patients in the control group had a thickened common flexor tendon which was of intermediate signal intensity on both T1-weighted and T2-weighted images. None of the patients in the control group had soft tissue edema around the common flexor tendon. MR imaging findings of patients with clinically diagnosed medial epicondylitis included thickening and increased T1 and T2 signal intensity of the common flexor tendon and soft tissue edema around the common flexor tendon. The presence of intermediate to high T2 signal intensity or high T2 signal intensity within the common flexor tendon and the presence of paratendinous soft tissue edema were the most specific findings of medial epicondylitis on MR imaging.

Part II of this comprehensive review on magnetic resonance imaging of the elbow discusses the role of magnetic resonance imaging in evaluating patients with abnormalities of the ligaments, tendons, and nerves of the elbow. Magnetic resonance imaging can yield high-quality multiplanar images which are useful in evaluating the soft tissue structures of the elbow. Magnetic resonance imaging can detect tears of the ulnar collateral ligament and lateral collateral ligament of the elbow with high sensitivity and specificity. Magnetic resonance imaging can determine the extent of tendon pathology in patients with medial epicondylitis and lateral epicondylitis. Magnetic resonance imaging can detect tears of the biceps tendon and triceps tendon and can distinguishing between partial and complete tendon rupture. Magnetic resonance imaging is also helpful in evaluating patients with nerve disorders at the elbow.

A 37-year-old military mechanic presented to our institution with a chronic history of a slowly enlarging left elbow antecubital fossa mass. There was no history of other chronic illness or trauma. Magnetic resonance imaging (MRI) and excisional biopsy revealed fatty villi and synovial inflammation within the left bicipitoradial bursa, consistent with lipoma arborescens. Four years later the patient presented with a 6-month history of swelling at the antecubital fossa of the opposite elbow. Diagnostic computed tomography and MRI examinations were performed. The surgical and pathologic findings confirmed the imaging diagnosis of lipoma arborescens at the right bicipitoradial bursa.

To retrospectively evaluate the qualitative and quantitative 3-T MR imaging features of the elbow in non-symptomatic professional baseball pitchers presenting as major league draft picks or trades. The Institutional Review Board (IRB) approved the HIPPA-compliant study. Informed consent was waived. Twenty-one professional non-symptomatic baseball pitchers (mean age 23, range 18 to 34 years old) underwent 3-T MR imaging of the pitching elbow. Two experienced readers independently performed qualitative (collateral ligaments, tendons, cartilage, bones, ulnar nerve, olecranon fossa, and joint fluid) and quantitative (collateral ligaments and posteromedial plica) evaluation. Descriptive statistics were calculated. Collateral ligament thickening was seen in a high proportion, nearly half, however, without features of full thickness tearing. Tendinosis without tearing was seen in 19 % (4/21) of common extensors. Cartilage abnormalities were infrequent. Bone abnormalities manifested as edema in 24 % (5/21) and humeroulnar osteophytosis. Ulnar nerve signal and/or morphologic abnormalities were seen in a very high proportion, up to 81 % (17/21). The olceranon fat pad showed scarring features in about one third. The median ligament thicknesses in mm measured: 4.6 UCL anterior bundle, 1.8 UCL posterior bundle, 1.9 RCL, 2.5 LUCL, and 0.7 mm anular. The median plica dimensions were 5.3 by 2.2 by 2.7 mm. High-resolution 3-T MR imaging frequently shows abnormalities involving the ligaments, tendons, nerves, olecranon fat pad, and bones in non-symptomatic baseball pitchers.

Ultrasonography (US) is an efficient alternative to magnetic resonance (MR) imaging for evaluation of soft tissues of the elbow. US is able to diagnose several abnormalities affecting tendons, muscles, ligaments and bursae around the elbow joint. In cubital tunnel syndrome, US identifies ulnar nerve abnormalities and extrinsic lesions that may cause nerve entrapment. Occult fractures, osteophytes and intra-articular loose bodies can also be imaged. In para-articular swelling, US is able to assess the presence of capsular and synovial processes and to differentiate them from soft tissue tumors. Key advantages of this technique include cost-effectiveness, availability and ability to perform a dynamic examination.