Elbow Joint Effusion Research Articles

Deep learning accurately classifies elbow joint effusion in adult and pediatric radiographs

Joint effusion due to elbow fractures are common among adults and children. Radiography is the most commonly used imaging procedure to diagnose elbow injuries. The purpose of the study was to investigate the diagnostic accuracy of deep convolutional neural network algorithms in joint effusion classification in pediatric and adult elbow radiographs. This retrospective study consisted of a total of 4423 radiographs in a 3-year period from 2017 to 2020. Data was randomly separated into training (n = 2672), validation (n = 892) and test set (n = 859). Two models using VGG16 as the base architecture were trained with either only lateral projection or with four projections (AP, LAT and Obliques). Three radiologists evaluated joint effusion separately on the test set. Accuracy, precision, recall, specificity, F1 measure, Cohen’s kappa, and two-sided 95% confidence intervals were calculated. Mean patient age was 34.4 years (1–98) and 47% were male patients. Trained deep learning framework showed an AUC of 0.951 (95% CI 0.946–0.955) and 0.906 (95% CI 0.89–0.91) for the lateral and four projection elbow joint images in the test set, respectively. Adult and pediatric patient groups separately showed an AUC of 0.966 and 0.924, respectively. Radiologists showed an average accuracy, sensitivity, specificity, precision, F1 score, and AUC of 92.8%, 91.7%, 93.6%, 91.07%, 91.4%, and 92.6%. There were no statistically significant differences between AUC's of the deep learning model and the radiologists (p value > 0.05). The model on the lateral dataset resulted in higher AUC compared to the model with four projection datasets. Using deep learning it is possible to achieve expert level diagnostic accuracy in elbow joint effusion classification in pediatric and adult radiographs. Deep learning used in this study can classify joint effusion in radiographs and can be used in image interpretation as an aid for radiologists.

The Effect of Acupuncture on Elbow Joint Sports Injuries Based on Magnetic Resonance Imaging.

Purpose Elbow joint injuries are extremely common in most athletes. Athletes' chronic elbow injuries can involve multiple complex anatomical structures related to orthopedics. Therefore, it is of great significance to explore the characteristics of magnetic resonance (MR) images of chronic sports injuries of the elbow joint and the influence of acupuncture treatment on MR images and clinical symptoms. Methods A total of 60 elbow joints of 39 athletes from 15-25 years old were selected for coronal, sagittal, and axial MR scans to observe the image characteristics; 60 elbow joints were randomly divided into acupuncture group and control group and observed changes in MR images and clinical symptoms after acupuncture treatment. Results After acupuncture treatment, the clinical symptoms were significantly improved. MR images showed that the elbow joint effusion was reduced, and the bone marrow edema was reduced. The effective rate of acupuncture treatment is as high as 100%, while the effective rate of the control group is only 40%. Acupuncture treatment has significantly improved the range of motion of the elbow joint. Conclusion Acupuncture treatment can significantly relieve athletes' elbow joint pain and locking symptoms, improve joint range of motion, and is beneficial to recovery of special training and high-level competitive competitions. It is a sensitive, effective, and noninvasive method.

A Soccer Fan’s Pain In The Elbow

HISTORY: A 35-year-old right-hand dominant male soccer fan presents with 3 days of acute right elbow pain. He began to experience progressive right lateral elbow pain while clapping exuberantly during a Seattle Sounders come from behind victory. He could recall no other trauma or inciting event. He had noticed some mild elbow soreness a few days preceding acute onset of pain. He endorsed elbow warmth and swelling as well as severe pain with any movement. He denied numbness, tingling, chills, fevers, fatigue, malaise. No prior history of rheumatic disease or gout. An x-ray obtained prior to presentation to our clinic showed small elbow joint effusion which the radiologist noted was suspicious for occult radial head fracture. PHYSICAL EXAMINATION: Swelling of right elbow with mild erythema. Decreased passive and active range of motion with elbow flexion, elbow extension, pronation, and supination. Tenderness to palpation overlying radial head as well as to olecranon bursa. Resisted wrist extension reproduced symptoms. Neurovascular exam was normal. DIFFERENTIAL DIAGNOSIS: 1. Occult radial head fracture 2. Lateral epicondylitis 3. Radial tunnel syndrome 4. Septic arthritis 5. Inflammatory arthropathy TEST AND RESULTS: X-ray: A small joint effusion suspicious for occult radial head fracture was noted. Ultrasound: Large elbow joint effusion tracking from the radiocapitellar joint deep to the triceps tendon insertion posteriorly. Common extensor tendon was intact. No swelling of the radial nerve visualized. Joint Aspiration: Joint aspiration revealed initially bloody then cloudy fluid. No organisms on gram stain or culture. Cell count revealed inflammatory joint aspirate containing over 50,000 WBCs of which 95% were neutrophils. Intracellular monosodium urate crystals were identified. FINAL WORKING DIAGNOSIS: Acute gout flare of right elbow TREATMENT AND OUTCOMES: Radiocapitellar joint steroid injection was performed due to ongoing pain despite oral NSAID use. Elbow pain resolved approximately 1 week after the injection. Dietary considerations were discussed. Patient advised to discuss uric acid lowering agents with PCP.

Inter-Observer Accuracy of “Fat Pad Sign” in Determining Radiological Elbow Joint Effusion with Different Levels of Experience

Abstract Background: Joint Effusion is considered as an important indicator of many joint morbid conditions. In the sitting of trauma, fat pad displacement in lateral elbow radiograph may be the only clue of occult fractures as it is referred to elbow effusion. Likewise, it's a sign of early internal joint morbidity in many articular diseases. The classic lateral radiograph is considered as the primary choice for determining elbow joint effusion because of being simple, available and reasonable tool. Aim of Study: The current study aimed to evaluate the inter-observer accuracy of fat pad signs of elbow lateral radiograph in detecting elbow joint effusion with the impact of observer experience on it. MRI was used as the gold standard. Patient and Methods: The current study is a descriptive validation study in which 52 patients were included prospec-tively in it. Inclusion criteria were positive elbow effusion by MRI with available lateral elbow radiograph within 3 days of the MRI study. Radiographs were read by 2 groups: Group I (2 senior radiology residents of 3 years' experience: Reader A & B), and group II (2 radiologists with MD degree, reader C & D). Each observer provided his readings by either proved effusion, denied effusion or asked for further evaluation. Readers were independently and blinded to the patients' clinical data. Results: The diagnostic accuracy percentages of elbow effusion detection for each reader compared to MRI were calculated as follows: Proper detection were from 59.6% to 61% in low experience, and 76.9% to 82.7% in high experience. Missed cases were (19%) in low experience and (3.8%) to (7.7%) in high experience group. While cases needed further evaluation were 19.2% to 21.2% in low experience and in high experience were ranging from 13.5% to 15.4%. Then agreement between each reader were estimated. The same level of experience showed perfect agreement, (Kappa of 0.922 and 0.965). While lower agreement was detected in different experience group with Kappa of 0.51 to 0.641, which is moderate and substantial agreement. Conclusion: The current study emphasizes that validity of radiographs in detection of elbow effusions widely varied with levels of experience. MRI is important beside lateral radiograph for detection of elbow effusion especially in low experience to avoid missed occult fractures and early morbid joint affection.

Proximal radius fractures in children: evaluation of associated elbow fractures

Additional fractures occur in association with proximal radius fractures, but the extent of these secondary injuries has not been systematically assessed. To ascertain the frequency and nature of additional fractures associated with proximal radius injuries in a large pediatric cohort. Radiographs meeting search criteria for proximal radius fracture during a 5-year period were reviewed. Fracture characteristics and the coexistence of additional elbow fractures were recorded and analyzed. The retrospective review was compared with initial interpretation and a blinded review by two pediatric musculoskeletal radiologists. Four hundred ninety-four proximal radius fractures were included. The radial neck was the most common fracture site (89%). Neck fractures occurred in younger patients (mean: 7.3years) than head fractures (mean: 13.3years) (P<0.001). Additional elbow fractures occurred in 39%, most commonly at the olecranon (22%). Additional fractures occurred in younger patients (mean: 7.2years) than isolated proximal radius fractures (mean: 8.5years) (P<0.001). Elbow joint effusion and complete or displaced radius fractures were each associated with additional elbow fractures (P<0.001). When compared with initial interpretation, 25% of additional fractures were not identified on initial radiographs, of which 44% were occult retrospectively. Fracture identification demonstrated excellent inter-reader reliability (interclass correlation coefficient [ICC]: 0.88, 0.94), but joint effusion interobserver agreement was only fair (ICC: 0.52, 0.41). Proximal radius fractures in children often occur in association with other elbow fractures, most commonly involving the olecranon. Enhanced awareness of these fracture patterns, especially in the setting of joint effusion or complete and displaced radius fractures, may improve detection to guide appropriate management.

Spontaneous Septic Arthritis of Canine Elbows: Twenty-One Cases.

This study provides information on clinical features, diagnosis, treatment and associated risk factors of spontaneous septic elbow arthritis in the dog. Medical records between March 2007 and June 2015 were searched for cases of spontaneous septic elbow arthritis with a diagnosis based on clinical signs, arthrocentesis, cytological and microbiological analysis of elbow joint synovial fluid, radiography and outcome following treatment. Twenty-one cases of septic arthritis were identified. Pre-existing osteoarthritis was present in 14/15 elbows for which diagnostic imaging was available. Although all cases had increased neutrophil count on synovial fluid cytology, culture was only positive in 12/21. Despite initial improvement in lameness scores (pre-treatment 9/10 [range: 1-10] versus post-treatment 3/10 [range: 1-5]), 11/12 had residual long-term lameness. Recurrence of infection was noted in 3/12 elbows for which long-term (>8 weeks) follow-up was available. There was an acute mortality rate of 2/21 associated with severe systemic sepsis. Septic arthritis, even in the absence of pyrexia, should be considered as a major differential diagnosis in middle aged, large breed dogs, with pre-existing elbow arthritis, that suffer an acute onset lameness, with elbow joint effusion and discomfort. Antibiotic therapy alone was effective for treatment with high initial response rates. Chronic lameness post-treatment was common, and a high rate of recurrence was seen with 3/12 dogs suffering more than one episode.

Detection of Traumatic Pediatric Elbow Joint Effusion Using a Deep Convolutional Neural Network

The purpose of this study is to determine whether a deep convolutional neural network (DCNN) trained on a dataset of limited size can accurately diagnose traumatic pediatric elbow effusion on lateral radiographs. A total of 901 lateral elbow radiographs from 882 pediatric patients who presented to the emergency department with upper extremity trauma were divided into a training set (657 images), a validation set (115 images), and an independent test set (129 images). The training set was used to train DCNNs of varying depth, architecture, and parameter initialization, some trained from randomly initialized parameter weights and others trained using parameter weights derived from pretraining on an ImageNet dataset. Hyperparameters were optimized using the validation set, and the DCNN with the highest ROC AUC on the validation set was selected for further performance testing on the test set. The final trained DCNN model had an ROC AUC of 0.985 (95% CI, 0.966-1.000) on the validation set and 0.943 (95% CI, 0.884-1.000) on the test set. On the test set, sensitivity was 0.909 (95% CI, 0.788-1.000), specificity was 0.906 (95% CI, 0.844-0.958), and accuracy was 0.907 (95% CI, 0.843-0.951). Accurate diagnosis of traumatic pediatric elbow joint effusion can be achieved using a DCNN.

Elbow Injury - Baseball

HISTORY: A 13-year-old male baseball player presented with intermittent lateral and posterior right elbow pain that became constant over the last month of travel baseball. The pain worsened in the cocking stage of throwing, and he reported decreased elbow extension. There was no numbness, tingling or weakness in his right upper extremity. Pain was a 4/10 at rest and worse with activity. PHYSICAL EXAMINATION: Slight right elbow effusion with tenderness over the olecranon and lateral and medial epicondyles. Range of motion was decreased to 15 degrees short of full extension. Range of motion did not elicit snapping of the triceps or ulnar nerve. There was pain with valgus stress of the right elbow but no instability. Strength of the upper extremity was normal with no pain elicited during strength testing. Tinel’s at the cubital tunnel was negative. DIFFERENTIAL DIAGNOSIS: 1. Osteochondritis Dissecans (OCD) of the capitellum 2. Panner’s Disease 3. Lateral/medial epicondylitis 4. Lateral/medial epicondyle apophysitis/avulsion fracture 5. Triceps tendinitis 6. Ulnar collateral ligament sprain 7. Olecranon stress fracture/loose body TEST AND RESULTS: Right elbow radiographs: -Small right elbow joint effusion Right elbow MRI: -Focal bone marrow signal changes in the anterior capitellum -Large joint effusion -Focal tiny subchondral fluid signal abnormality in mid capitellum -No visualized loose bodies -Suggestive of Panner disease or early OCD of the elbow Repeat right elbow MRI for increased pain after three weeks: -New 9 mm oval cartilaginous defect from the central capitellum, displaced in the medial joint recess posteriorly -No definite bony component -Underlying capitellar edema FINAL/WORKING DIAGNOSIS: -OCD of the capitellum TREATMENT AND OUTCOMES: 1. Right elbow arthroscopy with OCD drilling microfracture and loose body removal 2. Adjustable hinge elbow brace locked at 60–90 degrees of flexion for 2 weeks 3. Brace was loosened to 40–120 degrees after 2 weeks 4. Doing well at 5 week postoperative follow up. The brace was removed, and activities were restricted to no throwing activities for an additional 6 weeks. Then he was allowed slow return to throwing. 5. At one year follow up, he was doing well with no pain or symptoms. He was cleared for sports but instructed to refrain from pitching.

Long-standing Elbow Pain In A Gymnast

HISTORY: An 18-year-old female gymnast and cheerleader presented with right elbow pain for the last 8 months. The pain is constant and is associated with locking and catching in the elbow. Her symptoms are worsened with increased activity. She does not recall any trauma and is unsure how the injury occurred. Previously, she had an MRI done and was diagnosed with lateral epicondylosis by orthopedics. She has had 3 corticosteroid injections and has undergone a course of physical therapy without significant pain relief. PHYSICAL EXAM: Right upper extremity with normal shoulder and wrist exam. The elbow has full range of motion in flexion, extension, pronation, and supination. There is global tenderness to palpation over the lateral epicondyle, medial epicondyle, and olecranon. There is pain with valgus and varus stress of the elbow at 30 degrees without any gapping present. There is pain with the "milking" maneuver. There is no reproduction of catching or clicking. Tinel's over the extensor wad is equivocal. DIFFERENTIAL DIAGNOSIS: Lateral epicondylosis Elbow joint loose body UCL/RCL sprain Posterior interosseous nerve entrapment Elbow instability TEST AND RESULTS: MRI Pseudo-defect of the capitellum reported as normal Minor elbow joint effusion Diagnostic Ultrasound Swelling of posterior interosseous nerve just proximal to the arcade of Frohse Nerve measures 1.1mm in diameter compared with 0.7mm on the asymptomatic left side Nerve tapers abruptly as it enters the supinator muscle FINAL DIAGNOSIS: Posterior interosseous nerve entrapment TREATMENT AND OUTCOMES: 1. Ultrasound guided cortisone injection/fenestration at the arcade of Frohse 2. Temporary symptom relief after cortisone injection 3. Surgical release with decompression of posterior interosseous nerve 4. Returned to normal activities with full elbow range of motion without pain, catching, or locking

Bilateral Shoulder and Elbow Arthroscopy in Dogs with Forelimb Lameness: Diagnostic Findings and Treatment Outcomes

Characterize clinical findings and outcomes in dogs with forelimb lameness. Prospective case series. Dogs (n=19) with forelimb lameness. Dogs were included when lameness was attributed to shoulder and/or elbow pathology with informed consent for bilateral shoulder and elbow arthroscopy. Historical, clinical examination and diagnostic imaging findings were recorded. Localization of lameness was determined and subjective arthroscopic assessment of shoulders and elbows performed. Outcomes were subjectively assessed by owner survey. Dogs were lame in 1 (n=8) or both (11) forelimbs on admission. Lameness was localized to shoulders (8), elbows (6), or both (5). Preoperative localization was correct in 15 of 19 dogs (78.9%). Arthroscopic pathology was noted in 17 shoulders and 23 elbows. Orthopedic examination, spinatus muscle atrophy, abduction angles, elbow joint effusion, and radiographic assessment were clinically useful for preoperatively determining pathology. Eleven shoulders and 20 elbows were surgically treated. Dogs were significantly (P<.001) less lame at follow-up (mean+/-SD lameness score, 1.1+/-1.1) 6-24 months postoperatively compared with admission (4.2+/-2.8). Dogs with shoulder involvement only were significantly (P=.038) less lame than dogs with shoulder and elbow involvement after treatment. Most dogs (15) had mild to moderate lameness after treatment. Forelimb lameness in dogs may be associated with shoulder or elbow pathology or both. Preoperative localization and diagnosis based on examination, palpation, and radiography will be "correct" approximately 80% of the time. We recommend comprehensive assessment using history, orthopedic examination, joint-specific palpation, radiography, and arthroscopy, and following outcomes to determine cause of lameness, indications for treatment, optimal treatment, and accurate client communication for forelimb lameness in dogs.

Acute elbow trauma in children: role of ultrasonography

The diagnosis of occult elbow fracture in children is often challenging due to equivocal or negative repeated radiographic findings. To evaluate the potential diagnostic role of US in children who have sustained elbow trauma with an elbow joint effusion but no fracture seen on initial radiographs. The study included 14 consecutive children (age range 5-15 years) with elbow trauma whose elbow radiographs showed an effusion without fracture who underwent emergency imaging (within the first 72 h) with US and MRI. The aim of US was to demonstrate a lipohaemarthrosis in relation to a cortical fracture. MR imaging was used as the reference to differentiate fracture from bone or muscle contusions. In seven children US demonstrated a lipohaemarthrosis, and MRI demonstrated a cortical fracture in all these children. Conversely, among the seven children with simple haemarthrosis seen on US, MRI did not identify a cortical fracture in six and demonstrated a cortical fracture in one. Posttrauma elbow joint effusion in children is not always related to a cortical fracture. US appears to be a reliable, accurate, widely available and effective low-cost tool in these cases. The diagnostic clue is the detection of a lipohaemarthrosis in the articular recess.

Elbow Pain &amp; Rash in Adult Fisherman

HISTORY: HISTORY: 53 year male seen for rash with painful, swollen elbow 4 days after a weekend of ocean surf cast fishing. He denied trauma, stings or envenomation exposure. Onset at end of 2nd day of fishing; treated with ice, topical analgesics and diphenhydramine and oral NSAIDs & narcotics. Red pruritic rash started one day prior. He denied fever, chills or constitutional symptoms. Travel exposure 1 month prior included 3 week vacation to British Columbia where he experienced a diarrhea illness, self-limiting. PMH: Gout, obesity, hypertension, hyperglycemia, and ED. Surgical Hx: Right ulnar nerve transposition. PHYSICAL EXAMINATION: PHYSICAL EXAM Wt: 134.5 kg, T: 37.4, P: 84, Bp: 164/100, R: 20 The RUE from the proximal medial forearm into the mid upper arm: swollen & erythematous with focal tenderness medial joint line & small effusion. Supination and pronation pain free. Flexion and extension limited secondary to pain and swelling. Neurovascular: normal. Macular papular erythematous rash without vesicles or purulence extending to right pectoral region; no lymphadenopathy. Hand, wrist and shoulder exam normal. No other joint symptoms or findings. DIFFERENTIAL DIAGNOSIS: cellulitis septic arthritis infectious dermatitis fasciitis tendonitis venomous injury gout TEST AND RESULTS: Elbow: Hypertrophic degenerative changes, joint effusion, ossicle adjacent to medial epicondyles & deformity distal shaft humerus; both probable old fractures. Soft tissue swelling medially. MR (limited): Moderate elbow joint effusion and soft tissue edema primarily along the dorsal surface of the elbow without suggestion of osteomyelitis or abscess. Fluoroscopic guided needle aspiration: 10 cc cloudy yellow, WBC: 21,450, 92% segs, no organisms, no crystals, aerobic and anaerobic cultures: negative, AFB: negative. Admitting Labs: CBC, INR, Na, K, CL, uric acid, Cr, BUN, all normal. ESR: 24 ANA 1.2, CRP: 75.5. Blood cultures: neg. Lyme titer: neg. FINAL WORKING DIAGNOSIS: Septic arthritis TREATMENT AND OUTCOMES: IV clindamycin and piperacillin/tazabactam × 48 hours; D/C on oral clindamycin and IV ceftriaxone for a total of 14 days therapy. Follow-up at 4 days: no pain nor rash and full ROM and function.

MRI characteristics of olecranon bursitis.

Our aim was to describe the MRI characteristics of septic and nonseptic olecranon bursitis. MRI contrast-enhanced examinations (n = 19) of 35 patients with olecranon bursitis (septic, n = 14; nonseptic, n = 21) were jointly reviewed by two musculoskeletal radiologists. We evaluated bursa size, extent of marginal lobulation, septation, concomitant elbow joint effusion, soft-tissue edema, rim enhancement, soft-tissue enhancement, degree of fluid complexity, definition of bursa margins, presence of edema, thickening of the triceps tendon, and bone marrow edema. Comparison of septic and nonseptic bursitis yielded the following results: marginal lobulation, 79% (11/14) versus 48% (10/21), p = 0.14; bursa septation, 64% (9/14) versus 57% (12/21), p = 1.0; moderate or marked complexity of bursa fluid, 64% (9/14) versus 29% (6/21), p = 0.15; poorly defined margins, 64% (9/14) versus 67% (14/21), p = 1.0; elbow joint effusion, 86% (12/14) versus 52% (11/21), p = 0.12; moderate to marked soft-tissue edema, 64% (9/14) versus 33% (7/21), p = 0.1; edema of the triceps, 57% (8/14) versus 48% (10/21), p = 0.73; thickening of the triceps, 43% (6/14) versus 14% (3/21), p = 0.21; bone marrow edema, 29% (4/14) versus 5% (1/21), p = 0.13; rim enhancement, 100% (11/11) versus 75% (6/8), p = 0.31; soft-tissue enhancement, 100% (11/11) versus 63% (5/8), p = 0.1. Septic and nonseptic olecranon bursitis present with a considerable overlap of MRI findings without statistically significant differences. Septic olecranon bursitis can be excluded in the absence of bursal and soft-tissue enhancement.

The fat pad sign following elbow trauma in adults: its usefulness and reliability in suspecting occult fracture.

An elbow joint effusion with no fracture seen on radiographs after acute trauma has become synonymous with occult fracture. This study evaluates the incidence of fracture in such cases as determined by MR imaging and the predictive value of an elbow joint effusion. Twenty consecutive patients whose posttrauma elbow radiographs showed an effusion but no fracture and who were suitable for MR imaging were recruited. The elbow effusion size, represented by anterior and posterior fat pad displacement, was measured from the initial lateral elbow radiograph. Suitable candidates underwent MR imaging using a bone marrow sensitive sequence. The time between injury and MR imaging ranged from 0 to 12 days (mean 4 days). Seventy-five percent of the 20 patients who underwent MR imaging had radiographically occult fractures identified. Some (86.6%) of these fractures were located in the radial head, 6.7% were in the lateral epicondyle, and 6.7% were in the olecranon. Ninety percent had evidence of bone marrow edema. Fifteen percent had collateral ligament disruption identified on MR imaging, and 5% had a loose body. There was no change in patient management as a result of the additional imaging. The anterior fat pad displacement ranged from 5 to 15 mm (mean 9.25), and the posterior fat pad was elevated from 1 to 6 mm (mean 3.2). Our data using MR imaging suggests that fat pad elevation in the presence of recent trauma is frequently associated with a fracture. The size of the effusion, anterior/posterior fat pad elevation, or a combination of both does not correspond to the likelihood of an underlying fracture. MR imaging reveals a broad spectrum of bone and soft tissue injury beyond that recognizable on plain radiographs as demonstrated by all patients in this study.

Fractures of the elbow and forearm.

Fractures and dislocations of the elbow usually occur secondary to indirect trauma. In the adult, fractures of the distal humerus almost always involve the condyles. Fractures of the radial head and neck may be subtle, and the appearance of secondary signs, such as the elevated fat pads from an elbow joint effusion, may be diagnostically useful. Dislocations of the elbow can be associated with fractures, such as those involving the ulnar coronoid process. In children, the presence of epiphyseal and apophyseal ossification centers can confuse the inexperienced observer in the setting of elbow trauma. Osteochondral injury may be difficult to identify without adjunctive imaging techniques, such as magnetic resonance (MR) imaging. Soft tissue injury at the elbow is also well characterized by MR imaging. Fractures of a single forearm bone may occur in isolation, usually due to a direct blow, but these are usually associated with fracture of displacement of the other bone in that forearm.

Traumatic elbow effusions in pediatric patients: are occult fractures the rule?

Elbow joint effusion with no fracture seen on radiographs of pediatric patients after acute trauma has become synonymous with occult fracture. This study evaluates the incidence of occult fractures in such cases as determined by findings on follow-up radiographs. Initial and follow-up radiographs were reviewed for 54 children (mean age, 7 years) with a history of trauma who had joint effusion but no identifiable fracture on initial radiographs. The presence of periosteal reaction or bony sclerosis on follow-up radiographs was considered to be evidence of occult fracture. Mean time between initial and follow-up radiographs was 18 days (range, 14-50 days). Only nine (17%) of the 54 patients showed evidence of a healing occult fracture on follow-up radiographs. However, we found a statistically significant relationship (p = .001) between persistent joint effusion on follow-up radiographs and occult fracture. Seventy-eight percent of cases with occult fracture, versus 16% of cases without occult fracture, had persistent effusions. Joint effusion without visualized fracture on initial radiographs after trauma does not correlate with the presence of occult fracture in most cases (83%). Therefore, joint effusion as revealed by radiography should not be considered synonymous with occult fracture.

Ultrasonic demonstration of the elbow fat pads

Elevation of the fat pads around the elbow joint is a well recognised radiological sign of a joint effusion which may be due to trauma or other inflammatory process. There are occasions when plain radiographs fail to demonstrate this sign. A case is reported in which elevation of the posterior fat pad and an elbow joint effusion were demonstrated ultrasonically. Comparative ultrasound examination of the normal elbow in this patient and examination of 40 normal elbows, in adults and children, consistently demonstrated the normal anterior and posterior fat pads except in one patient aged 4 days where the fat pads could not be clearly seen. The normal ultrasonic appearances are described. Ultrasound examination may be useful in patients where plain radiographs have failed to demonstrate the position of the fat pads.

Changes due to trauma in the fat plane overlying the supinator muscle: a radiologic sign.

Aradiolucent fat plane may be recognized parallel to the ventral aspect of the proximal one third of the radius in virtually all normal lateral radiographs of the elbow. Alterations are seen in trauma or inflammatory disease processes. Recognition of widening, blurring, and ventral displacement is often useful in interpretation. It has been found to be particularly helpful in subtle fractures of the.head and neck of the radius. Anatomic Observations A twenty-three year old male fell on his outstretched hand (Case I). The lateral view of the opposite normal elbow, Figure 1, A, illustrates a well defined radiolucent line (arrowheads). It arises from the elbow joint and runs distally in a gentle ventral curve parallel to the proximal third of the radius. In contrast, the usual distortion associated with radial head and neck fracture is demonstrated in Figure 1, B with the fat line widened, blurred, and ventrally displaced. Figure 1, C is an oblique view, obtained because of the soft-tissue findings, which illustrates a fissure fracture of the radial head which was not evident in the frontal film. The location of the fat line was established by anatomic dissection of the cadaver elbow joint in which the fat plane was observed radiologically in the true lateral projection prior to the dissection. The immediate posterior relations of the fat plane are the supinator muscle and the proximal end of the radius. The principal anterior relations are the pronator teres and the brachioradialis muscles. In the majority of adults, the fat plane lies within one cm from the ventral margin of the radius. In patients with very muscular arms, this distance may range up to 1.3 cm. The variation between two normal sides is usually only 1 to 2 mm, whereas the difference noted with a fracture is invariably much greater. Radiologic Observations Two hundred and fifty consecutive cases of elbow trauma were reviewed. During the period of study a lateral film of the opposite normal elbow was obtained for comparison. The records of an additional 50 adult patients with nontraumatic conditions, principally arthritides and infections of the elbow joint, were also reviewed. Fifty pediatric cases of elbow injury from Winnipeg Children's Hospital and Montreal Children's Hospital were also assessed in a similar manner. Radial head and neck fractures constitute the group of greatest interest because this type of fracture may be overlooked in the initial radiologic assessment. In all radial head and neck fractures observed, supinator fat plane changes were present. Another constant feature was the radiologic sign of elbow joint effusion. Several fractures were not initially recognized by experienced radiologists due to subtle fracture lines and the absence of displacement of the fragments. However, because of both supinator fat plane changes and joint effusion, oblique films were obtained and established a radial head and/or neck fracture.