Magnetic resonance imaging of the musculoskeletal system: Part 3. The elbow

Thin-slice elbow MRI with deep learning reconstruction: Superior diagnostic performance of elbow ligament pathologies

PURPOSE

With the slice thickness routinely used in elbow MRI, small or subtle lesions may be overlooked or misinterpreted as insignificant. To compare 1 mm slice thickness MRI (1 mm MRI) with deep learning reconstruction (DLR) to 3 mm slice thickness MRI (3 mm MRI) without/with DLR, and 1 mm MRI without DLR regarding image quality and diagnostic performance for elbow tendons and ligaments.

METHODS

This retrospective study included 53 patients between February 2021 and January 2022, who underwent 3 T elbow MRI, including T2-weighted fat-saturated coronal 3 mm and 1 mm MRI without/with DLR. Two radiologists independently assessed four MRI scans for image quality and artefacts, and identified the pathologies of the five elbow tendons and ligaments. In 19 patients underwent elbow surgery after elbow MRI, diagnostic performance was evaluated using surgical records as a reference standard.

RESULTS

For both readers, 3 mm MRI with DLR had significant higher image quality scores than 3 mm MRI without DLR and 1 mm MRI with DLR (all P < 0.01). For common extensor tendon and elbow ligament pathologies, 1 mm MRI with DLR showed the highest number of pathologies for both readers. The 1 mm MRI with DLR had the highest kappa values for all tendons and ligaments. For reader 1, 1 mm MRI with DLR showed superior diagnostic performance than 3 mm MRI without/with DLR. For reader 2, 1 mm MRI with DLR showed the highest diagnostic performance; however, there was no significant difference.

CONCLUSIONS

One mm MRI with DLR showed the highest diagnostic performance for evaluating elbow tendon and ligament pathologies, with similar subjective image qualities and artefacts.

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

MRI of the Elbow: How to Do It

The diagnostic cascade for elbow complaints starts with the physical examination and radiographs that already can clarify or rule out many causes. Depending on the suspected pathology, additional imaging is necessary. Magnetic resonance imaging (MRI) has the advantage of accurately demonstrating a broad spectrum of diseases. The main indication for noncontrast MRI of the elbow is chronic epicondylitis. For magnetic resonance (MR) arthrography, it is suspected chondral and osteochondral abnormalities. Indirect MR arthrography is an option when direct arthrography is not practicable. MR arthrography of the elbow with traction is feasible, with promising results for the assessment of the radiocapitellar cartilage.

Distal biceps and triceps injuries in athletes

Biceps and triceps ruptures are rare, but can cause significant disability. They typically result from a forceful eccentric contraction, resulting in weakness and pain. Biceps and triceps tendon injuries represent the most and least common tendinous injuries about the elbow, respectively. Nonoperative management of these injuries is generally reserved for partial ruptures or patients unfit for surgery. Surgical repair has become the preferred method of treatment for acute, complete ruptures. Anatomy, epidemiology, clinical evaluation, and treatment of these injuries are described in this review.

Distal biceps and triceps ruptures

Biceps and triceps tendon ruptures are rather uncommon injuries and are most commonly diagnosed clinically. Magnetic resonance imaging can help the clinician to differentiate an incomplete tear and define any degeneration of the tendon. Surgical anatomical repair is typically performed in acute complete ruptures whereas nonoperative treatment can be used for partial ruptures, as well as for patients unfit for surgery. Single incision techniques are associated with a higher rate of nerve injuries, while double incision repairs have a higher prevalence of heterotopic ossification. Although various fixation methods have been applied including bone tunnels, interference screws, suture anchors, cortical button fixation, the current evidence does not support the superiority of one method over the other. A well-planned postoperative rehabilitation programme is essential for a good final outcome. As better fixation devices are being used, more aggressive rehabilitation programmes have been applied. Epidemiology, clinical evaluation, diagnosis, surgical and conservative management of these injuries are presented in this review along with the authors' preferred technique for the anatomical repair of acute complete ruptures.

Triceps tendon reconstruction using ipsilateral palmaris longus autograft in unrecognized chronic tears

Injury to the distal triceps tendon is uncommon and can be difficult to diagnose, especially when a partial rupture or tear occurs. In situations where an incomplete disruption to the musculotendinous unit occurs, a palpable defect or clear functional loss may not be present. Advanced imaging techniques, such as magnetic resonance imaging or ultrasound, can be used to confirm the diagnosis and define the extent of injury. The treatment of a complete rupture of the distal triceps tendon is repair or reconstruction, whereas the management of a patient with a partial triceps rupture is related to the pain, functional deficit, and expectations of the patient. This article presents 2 patients with chronic, near complete disruptions of the distal triceps tendon. In both patients, surgical reconstruction of the injured tendon was accomplished using ipsilateral palmaris longus autograft. This technique allows the treating surgeon to harvest the graft from the ipsilateral upper extremity. The palmaris autograft is then used to reconstruct the injured portion of the triceps tendon using a Pulvertaft weave technique through the intact triceps tendon and osseous tunnels within the proximal ulna. This technique allows for easy surgical setup and harvest of autograft tendon and provides a structurally sound technique for a tension-free reconstruction of the injured tendon. It also permits early postoperative elbow range of motion, with active elbow extension allowed at 6 weeks. The authors have used this technique successfully in the treatment of chronic partial tears of the distal triceps tendon.

Operative versus non-operative management of pediatric medial epicondyle fractures: a systematic review

PURPOSE

There is ongoing debate about the management of medial epicondyle fractures in the pediatric population. This systematic review evaluated non-operative versus operative treatment of medial epicondyle fractures in pediatric and adolescent patients over the last six decades.

METHODS

A systematic review of the available literature was performed. Frequency-weighted mean union times were used to compare union rates for closed versus open treatments. Moreover, functional outcomes and range-of-motion variables were correlated with varying treatment modalities. Any complications, including ulnar nerve symptoms, pain, instability, infection, and residual deformity, were cataloged.

RESULTS

Fourteen studies, encompassing 498 patients, met the inclusion/exclusion criteria. There were 261 males and 132 female patients; the frequency-weighted average age was 11.93 years. The follow-up range was 6-216 months. Under the cumulative random effects model, the odds of union with operative fixation was 9.33 times the odds of union with non-operative treatment (P < 0.0001). There was no significant difference between operative and non-operative treatments in terms of pain at final follow-up (P = 0.73) or ulnar nerve symptoms (P = 0.412).

CONCLUSIONS

Operative treatment affords a significantly higher union rate over the non-operative management of medial epicondyle fractures. There was no difference in pain at final follow-up between operative and non-operative treatments. As surgical indications evolve, and the functional demands of pediatric patients increase, surgical fixation should be strongly considered to achieve stable fixation and bony union.

Nonoperative treatment for osteochondritis dissecans of the capitellum

BACKGROUND

Spontaneous healing potential and progression of osteochondritis dissecans of the capitellum have been unclear.

HYPOTHESIS

Healing potential is high in the early stage of osteochondritis dissecans and low in the advanced stage.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This retrospective study examines 39 patients with osteochondritis dissecans of the capitellum who were treated conservatively. All patients were baseball players (mean age, 12.8 years). After initial examination, all patients were advised to stop heavy use of the elbow. Physical and radiographic examinations were regularly performed and assessed. Mean duration of follow-up was 14.4 months.

RESULTS

Early-stage lesions were present in 30 patients, while 9 patients were diagnosed with advanced lesions. Open capitellar growth plates were observed in 17 patients, and closed capitellar growth plates were seen in 22 patients. On final radiography, 25 of 30 early-stage lesions were assessed as healed. However, only 1 of 9 advanced-stage lesions was assessed as healed. The remaining 8 advanced lesions were unimproved or progressed. Healing of lesions was seen in 16 of 17 patients with an open growth plate and in 11 of 22 patients with a closed growth plate, representing a significant difference between patients with open and closed growth plates (P < .05).

CONCLUSION

Spontaneous healing potential of osteochondritis dissecans in early lesions, especially in patients with open capitellar growth plates, appears high, and nonoperative treatment is appropriate. Conversely, healing potential is extremely low in advanced osteochondritis dissecans lesions. Surgical intervention is recommended to achieve lesion healing in advanced cases.

Using sonography for the early detection of elbow injuries among young baseball players

OBJECTIVE

The aim of this study was to determine the usefulness of sonography for detecting elbow injuries among young baseball players.

SUBJECTS AND METHODS

One hundred fifty-three volunteers ranging in age from 9 to 12 years and belonging to youth baseball teams participated. Sonography of the elbow was performed in the field when baseball exercises were being conducted. We analyzed the relationship between elbow pain and sonographic abnormalities and the relationship between pitchers and sonographic abnormalities.

RESULTS

Sonography showed that 33 subjects had medial epicondylar fragmentation and two had early-stage osteochondritis dissecans of the capitellum. In 25 subjects who agreed to further examination and treatment, radiography confirmed the sonographic findings. All of the 23 subjects with medial epicondylar fragmentation, who stopped throwing, obtained union of the bone and returned to baseball. The two subjects with osteochondritis dissecans of the capitellum underwent surgery before the osteochondral fragment became loosened. Sonographic abnormalities correlated with episodes of elbow pain. Pitchers statistically significantly had sonographic abnormalities.

CONCLUSION

Sonography in the field can provide an opportunity to detect and treat elbow injuries before they become more advanced.

Magnetic resonance imaging of the elbow: update on current techniques and indications

The utility of magnetic resonance imaging of the elbow has noticeably improved over the past decade. Advances in equipment and refinement of pulse sequences has allowed for superior visualization of many pathologic processes involving the elbow joint and its surrounding structures. At this time, magnetic resonance imaging is most valuable in detecting occult fractures, osteochondritis dissecans, collateral ligament tears, nonossified intra-articular loose bodies, and soft tissue masses. It may also aid in the diagnosis of tendinous injuries, compression neuropathies, and synovial disorders. This article serves as an educational update for hand surgeons and illustrates the features of normal anatomy and specific disorders of the elbow.

The "moving valgus stress test" for medial collateral ligament tears of the elbow

BACKGROUND

The diagnosis of a painful partial tear of the medial collateral ligament in overhead-throwing athletes is challenging, even for experienced elbow surgeons and despite the use of sophisticated imaging techniques.

HYPOTHESIS

The "moving valgus stress test" is an accurate physical examination technique for diagnosis of medial collateral ligament attenuation in the elbow.

STUDY DESIGN

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

METHODS

Twenty-one patients underwent surgical intervention for medial elbow pain due to medial collateral ligament insufficiency or other abnormality of chronic valgus overload, and they were assessed preoperatively with an examination called the moving valgus stress test. To perform the moving valgus stress test, the examiner applies and maintains a constant moderate valgus torque to the fully flexed elbow and then quickly extends the elbow. The test is positive if the medial elbow pain is reproduced at the medial collateral ligament and is at maximum between 120 degrees and 70 degrees.

RESULTS

The moving valgus stress test was highly sensitive (100%, 17 of 17 patients) and specific (75%, 3 of 4 patients) when compared to assessment of the medial collateral ligament by surgical exploration or arthroscopic valgus stress testing. The mean shear range (ie, the arc within which pain was produced with the moving valgus stress test) was 120 degrees to 70 degrees. The mean angle at which pain was at a maximum was 90 degrees of elbow flexion.

CONCLUSIONS

The moving valgus stress test is an accurate physical examination technique that, when performed and interpreted correctly, is highly sensitive for medial elbow pain arising from the medial collateral ligament.

Biceps tendon and triceps tendon injuries

Injuries to the biceps and triceps tendons about the elbow are relatively infrequent. Typically, they are traumatic events that occur as a result of a forceful eccentric contraction. Early recognition of these injuries and prompt intervention are the cornerstones to a successful outcome. Acute anatomic repair of complete injuries offers predictably good results. Conservative management, on the other hand, is typically reserved for partial injuries with little functional compromise, and for patients unfit for surgery. The challenges posed by chronic injuries can be addressed with a variety of surgical options. This article focuses on the timely identification and diagnosis of these injuries and specific indications and guidelines for their treatment.

Surgical treatment of distal triceps ruptures

BACKGROUND

Distal triceps tendon ruptures occur rarely, and the diagnosis is often missed when the injury is acute. The literature provides little guidance regarding treatment or the outcome of treatment of these injuries. The goal of this report was to present our experience with the diagnosis, timing and technique of surgical treatment, and outcome of treatment of distal triceps tendon ruptures in twenty-two patients. None of the ruptures followed joint replacement.

METHODS

Twenty-three procedures were performed in twenty-two patients with an average age of forty-seven years. The average duration of follow-up was ninety-three months (range, seven to 264 months). Data were obtained by a retrospective review of records and radiographs before and after surgery. Also, thirteen patients returned for follow-up and were examined clinically. Six additional patients responded to a telephone questionnaire. One patient was lost to follow-up, and two had died. Formal biomechanical evaluation of isokinetic strength and isokinetic work was performed in eight patients, at an average of eighty-eight months after surgery. Isokinetic strength data were available from the charts of two additional patients.

RESULTS

Ten of the triceps tendon ruptures were initially misdiagnosed. At the time of diagnosis, triceps weakness with a decreased active range of motion was found in most patients, and a palpable defect in the tendon was noted after sixteen ruptures. Operative findings revealed a complete tendon rupture in eight cases and partial injuries in fifteen. Fourteen primary repairs and nine reconstructions of various types were performed. Three of the primary repairs were followed by rerupture. At the time of follow-up, the range of elbow motion averaged 10 degrees to 136 degrees. All but two elbows had a functional range of motion; however, the lack of a functional range in the two elbows was probably due to posttraumatic arthritis and not to the triceps tendon rupture. Triceps strength was noted to be 4/5 or 5/5 on manual testing in all examined subjects. Isokinetic testing of ten patients showed that peak strength was, on the average, 82% of that of the untreated extremity. Testing showed the average endurance of the involved extremity to be 99% of that of the uninvolved arm. The results after repair and reconstruction were comparable, but the patients' recovery was slower after reconstruction.

CONCLUSIONS

The diagnosis of distal triceps tendon rupture is often missed when the injury is acute because of swelling and pain. Primary repair of the ruptured tendon is always possible when it is performed within three weeks after the injury. When the diagnosis is in doubt immediately after an injury, the patient should be followed closely and should be reexamined after the swelling and pain have diminished so that treatment can be instituted before the end of this three-week period. Reconstruction of the tendon is a much more complex, challenging procedure, and the postoperative recovery is slower. Thus, we believe that early surgical repair, within three weeks after the injury, is the treatment of choice for distal triceps tendon ruptures. of evidence.

Sonography of the medial collateral ligament of the elbow: a study of cadavers and healthy adult male volunteers

OBJECTIVE

We assessed the ability of high-resolution sonography to reveal the size and echogenicity of the anterior bundle of the normal medial collateral ligament of the elbow in cadavers and uninjured male volunteers.

MATERIALS AND METHODS

The anterior bundle of the medial collateral ligament in five cadaveric elbows was imaged and injected with contrast material by experienced musculoskeletal radiologists using a 12-MHz linear array transducer. Immediate ligament dissection was performed. The bilateral ligaments in 30 healthy 21- to 34-year-old male volunteers were imaged with gravitational stress. Of these, five randomly selected subjects also received approximately 5 lb (11.3 kg) of applied stress.

RESULTS

Contrast material was injected directly into all five cadaveric ligaments. The anterior bundle of the medial collateral ligament in all 30 asymptomatic male volunteers was hyperechoic in comparison with surrounding muscle and had a fibrillar pattern and fanlike shape. Its mean dimensions were 2.6 +/- 0.31 x 2.2 +/- 0.47 x 4.0 +/- 0.88 mm on the right and 2.6 +/- 0.36 x 2.1 +/- 0.42 x 4.0 +/- 0.86 mm on the left, in longitudinal short, transverse short, and transverse long axes, respectively. Differences in ligament measurements in sidedness, stress application, and hand dominance did not approach statistical (Bonferroni corrected, p > 0.01) or clinical (all differences, <0.2 mm) significance.

CONCLUSION

Radiologists can accurately use sonography to identify and measure the size of the anterior bundle of the normal medial collateral ligament of the elbow. These baseline parameters for the normal ligament may prove useful when evaluating the injured ligament.

Stress injury of the proximal ulna in professional baseball players

BACKGROUND

To date, stress injury of the proximal ulna has been infrequently reported as a cause of elbow pain in the throwing athlete.

PURPOSE

We describe a syndrome of osseous stress injury of the proximal ulna in the professional throwing athlete.

STUDY DESIGN

Retrospective review.

METHODS

We evaluated the clinical, radiographic, and magnetic resonance imaging findings of seven professional baseball players with osseous stress injury of the proximal ulna.

RESULTS

Plain radiographs of the involved elbows failed to demonstrate any significant findings. All of the clinically significant lesions were detected with magnetic resonance imaging. In addition, magnetic resonance imaging was found to be of value in following the course of healing of the injuries. All of the lesions originated on the posteromedial aspect of the proximal ulna. The ulnar collateral ligament was intact in all seven athletes. One athlete had two occurrences of this injury. Six of the seven athletes returned to their previous level of play after a nonoperative course of treatment.

CONCLUSIONS

We believe that this injury should be considered in the differential diagnosis of elbow pain in the throwing athlete. Magnetic resonance imaging is the diagnostic test of choice when this injury is suspected.

Ultrasonographic assessment of the ulnar collateral ligament and medial elbow laxity in college baseball players

BACKGROUND

The prevalence of medial elbow instability is high in athletes who throw, such as baseball players. The aim of this study was to assess the medial aspect of the elbow with ultrasonography to detect changes in baseball players.

METHODS

Ultrasonography of the medial aspect of the elbow was performed, while gravity stress was applied with the elbow in 90 degrees of flexion, on thirty college baseball players (twelve pitchers and eighteen fielders) to assess medial joint laxity and deformity of the ulnar collateral ligament. The dominant (throwing) extremity was compared with the contralateral extremity. Clinical data were correlated with ultrasonographic findings.

RESULTS

The medial joint space was significantly wider on the throwing side than it was on the contralateral side (2.7 mm and 1.6 mm, respectively; p < 0.01), and the proximal part of the ulna was shifted significantly laterally on the throwing side (p < 0.01). Angular deformity of the ulnar collateral ligament was found in five subjects, and it was significantly associated with lateral shift of the proximal part of the ulna (p < 0.01). Medial elbow pain was associated with widening of the medial joint space (p < 0.05) and with the presence of angulation of the ulnar collateral ligament (p < 0.01).

CONCLUSIONS

Medial elbow laxity and elbow valgus on the throwing side of baseball players were increased compared with those in nonplayers. Angular deformity of the ulnar collateral ligament suggests that the ligament bends over the distal-medial edge of the trochlea. Ultrasonography can provide useful information about the condition of the ulnar collateral ligament and about medial elbow laxity in athletes who throw.

Imaging of elbow injuries in the child and adult athlete

Because of the often complex and sometimes poorly remembered history of trauma to the elbow, imaging beyond conventional plain film radiographs is often needed. Usually, this consists of high-resolution MR imaging to evaluate the articular cartilage, supporting ligaments, and tendons about the elbow. Sonography, however, can also be used, especially when there is a targeted clinical question as to the presence of epicondylitis, or to provide guidance for diagnostic or therapeutic injections.

Osteochondritis dissecans of the humeral capitellum. Diagnosis and treatment

Elbow pain seen in the at-risk athlete, such as a baseball player (in particular, a pitcher) or gymnast, should raise suspicion for OCD. OCD of the humeral capitellum remains a difficult problem to treat. Once radiographic changes are obvious, long-term studies suggest that half of affected individuals will be symptomatic. Currently, the key to successful treatment is early detection. Gymnasts, in general, fare worse in returning to sport. The reason is not entirely clear but is likely related to the amount of force directed across the elbow and the nature of the sport. Pitchers sometimes can be returned, but to another position. Radiographs remain the screening test of choice but can give the surgeon a false sense of security, because changes early in the disease process may not be obvious radiographically. Views at 45 degrees flexion and contralateral elbow views are helpful. The advent of MR imaging now allows the practicing orthopaedic surgeon to assess very early lesions effectively that might otherwise be underappreciated on radiographs. With more advanced lesions, radiographic findings are more obvious and demonstrate the more classic capitellar fragment with a surrounding zone of lucency. MR imaging is this setting is helpful in assessing the overlying articular cartilage and, hence, the stability of the fragment. In the absence of obvious loose bodies or mechanical symptoms, rest is the first step in treatment. If symptoms persist, then operative intervention is indicated. About half of these patients heal with nonoperative treatment. Pretreatment assessment of fragment viability has not traditionally been incorporated into the treatment algorithm. Recent anecdotal evidence suggests that stability and viability of a fragment can be assessed using intravenous contrast. Knowledge of the fragment viability could allow those lesions likely to heal without surgical intervention to be distinguished from those requiring surgical intervention. The procedure should be chosen based on the size of the lesion and the integrity of the subchondral bone. Subchondral drilling and microfracture can only resurface defects and cannot reconstitute subchondral bone. Autologous chondrocyte implantation has limited ability to address subchondral bone loss, whereas autograft and allograft osteochondral transplantation can restore subchondral bone. Most authors would agree that there is no role currently for reduction and fixation of long-standing, free loose bodies. No consensus exists regarding acute dislodging of an in situ loose fragment. Long-term results after radiographic changes are present suggest a degenerative course in about half the patients. Whether the newer techniques of cartilage resurfacing will significantly impact the natural history of this process remains to be seen.

Distal biceps tendon injuries: diagnosis and management

Rupture of the distal biceps tendon occurs most commonly in the dominant extremity of men between 40 and 60 years of age when an unexpected extension force is applied to the flexed arm. Although previously thought to be an uncommon injury, distal biceps tendon ruptures are being reported with increasing frequency. The rupture typically occurs at the tendon insertion into the radial tuberosity in an area of preexisting tendon degeneration. The diagnosis is made on the basis of a history of a painful, tearing sensation in the antecubital region. Physical examination demonstrates a palpable and visible deformity of the distal biceps muscle belly with weakness in flexion and supination. The ability to palpate the tendon in the antecubital fossa may indicate partial tearing of the biceps tendon. Plain radiographs may show hypertrophic bone formation at the radial tuberosity. Magnetic resonance imaging is generally not required to diagnose a complete rupture but may be useful in the case of a partial rupture. Early surgical reattachment to the radial tuberosity is recommended for optimal results. A modified two-incision technique is the most widely used method of repair, but anterior single-incision techniques may be equally effective provided the radial nerve is protected. The patient with a chronic rupture may benefit from surgical reattachment, but proximal retraction and scarring of the muscle belly can make tendon mobilization difficult, and inadequate length of the distal biceps tendon may necessitate tendon augmentation. Postoperative rehabilitation must emphasize protected return of motion for the first 8 weeks after repair. Formal strengthening may begin as early as 8 weeks, with a return to unrestricted activities, including lifting, by 5 months.

Magnetic resonance imaging of the elbow

Magnetic resonance imaging (MRI) provides useful information regarding the elbow joint. Many abnormalities seen in the elbow are a result of trauma, often from sports such as baseball and tennis. Elbow problems are frequently related to the medial tension-lateral compression phenomenon where repeated valgus stress produces flexor-pronator strain, ulnar collateral ligament sprain, ulnar traction spurring, and ulnar neuropathy. The lateral compression causes osteochondritis dissecans of the capitellum and radial head, degenerative arthritis, and loose bodies. Other elbow abnormalities seen on MRI include radial collateral ligament injuries, biceps and triceps tendon injuries, other nerve entrapment syndromes, loose bodies, osseous and soft tissue trauma, arthritis, and masses, including bursae.