The Relationship between the Bevel of the Radial Head Epiphysis and the Posterior Synovial Fringe During Rotation of the Elbow: An Ultrasonography Study with Possible Implications Regarding the Pathophysiology of Nursemaid's Elbow

BACKGROUND

Nursemaid's elbow is the most common upper extremity injury in children under 5 years of age. However, the exact pathomechanism underlying the nursemaid's elbow remains elusive, and approximate one-third of patients present with a nonclassical history. Using a high-frequency ultrasound probe, we attempted to determine the relationship between the anterior edge of the posterior synovial fringe and the peripheral rim of the radial head epiphysis during rotation. It is possible that the primary reason for the nursemaid's elbow is due to the pronator position.

METHODS

Twenty-one patients had a history of nursemaid's elbow and had a successful reduction before enrollment in this study. A high-frequency linear array 6 to 24 MHz hockey stick transducer was used to detect small morphologic changes in the peripheral rim of the radial head epiphysis and the posterior synovial fringe during rotation of the capitellum-radial joint.

RESULTS

In complete pronation, the anterior edge of the posterior synovial fringe contacts the beveled articular surface of the radial head peripheral rim in all 21 patients. In neutral and complete supination, the anterior edge of the posterior synovial fringe contacts the convexly nonarticular surface of the radial head peripheral rim and extends deep into the foveal radius. The posterior synovial fringe and the capsule-aponeurotic membrane were tightened in passive pronation in all 21 cases. The posterior synovial fringe and the capsule-aponeurosis membrane were all loose in the neutral and supination positions.

CONCLUSION

The anterior edge of the posterior synovial fringe touches the beveled peripheral rim of the radial head epiphysis during complete pronation, and the tension of the lateral collateral ligament complex during pronation may further cause unstable conditions of the anterior edge of the posterior synovial fringe. We hypothesized that the beveled peripheral rim of the radial epiphysis and its relationship with the anterior edge of the posterior synovial fringe could be the reason why nursemaid's elbow only occurs while the elbow is in the pronator position.

The Usefulness of Dynamic Ultrasonography in Nursemaid's Elbow: A Prospective Case Series of 13 Patients Reconsideration of the Pathophysiology of Nursemaid's Elbow

BACKGROUND

Nursemaid's elbow is a common musculoskeletal disorder among children under 5 years of age. However, diagnostic imaging to confirm a nursemaid's elbow diagnosis is still unavailable. Through the use of a high-frequency ultrasound probe, we determined the etiology and possible pathophysiology of nursemaid's elbow.

METHODS

Thirteen consecutive patients with the clinical suspicion of nursemaid's elbows were examined. A high-frequency linear array 6 to 24 MHz hockey stick transducer was used to detect small changes (partial eclipse signs) of the radial head in the axial view before and after manipulation.

RESULTS

All patients in this study had a successful reduction. A partial eclipse sign was found in all patients before reduction and disappeared after successful reduction.

CONCLUSION

These pathologic features detected through high-frequency ultrasonography suggest the role of the escaped posterior synovial fringe in the pathogenesis of the nursemaid's elbow. The specific finding of a "partial eclipse sign" could be a useful additional clue leading to the correct diagnosis of the nursemaid's elbow and may help avoid the unnecessary reduction in patients who do not have a "partial eclipse sign".

LEVEL OF EVIDENCE

Level II, diagnostic studies.

Use Of POCUS for the Paediatric Patient with an Undifferentiated Upper Limb Injury

A 2-year-old girl presented to the Paediatric Emergency Department following an unwitnessed injury to her left arm while playing at nursery limiting further examination. On assessment she was reluctant to use her left arm and further examination was difficult. In cases of unwitnessed and undifferentiated elbow injuries point of care ultrasound (POCUS) can be used to evaluate for elbow joint effusion, fracture, or radial head subluxation, also known as nursemaid's elbow. Pulled elbow is a commonly encountered paediatric injury but based on the history and examination findings it may not always be obvious. We present an approach to the child with an undifferentiated elbow injury incorporating POCUS as a means of increasing the reliability of findings on clinical examination.

Role of the supinator muscle in the pathophysiological mechanism of a pulled elbow

A pulled elbow is a common childhood orthopaedic injury that is usually caused by longitudinal traction on the hand. The pathophysiological mechanism of a pulled elbow involves interposition of the annular ligament into the radiohumeral joint. Recent ultrasonographic studies have shown that both the supinator muscle and annular ligament were trapped into the radiohumeral joint. This paper discusses why pulled elbows can occur during pronation and how a pulled elbow can be reduced either by hyperpronation or supination followed by elbow flexion based on the function of the supinator muscle.

Fifteen-minute consultation: Assessing the child with an elbow injury

This article aims to provide a concise summary of the key considerations when assessing a child with an elbow injury. Elbow injuries are common with acute elbow trauma, accounting for 2%-3% of all visits to the emergency department. This article will cover history, examination and key X-ray findings, along with a brief guide to management. It is hoped this article will help healthcare professionals who assess children with elbow injuries. Our work is applicable to those both in the hospital and community setting.

Nursemaid's Elbow - Supination-flexion Technique Versus Hyperpronation/forced Pronation: Randomized Clinical Study

BACKGROUND

Nursemaid's elbow (NE) represents the most common pathology met in the pediatric orthopedics ambulatory. There are two techniques of reducing the NE: the supination-flexion technique and the hyperpronation or forced pronation technique.

MATERIALS AND METHODS

In this randomized clinical study, we aim to compare the two reduction techniques of the NE, by measuring the effectiveness of each and scaling the pain felt by the child, by using the Faces Pain Scale. The study included 116 patients with typical presentation for NE with age under 7 years old (mean age ~3 years old), 45% of males and 55% of females.

RESULTS

Hyperpronation was found to be more successful than supination-flexion technique as a first attempt (85% vs. 53%), second attempt (50% vs. 28%), and as a crossover technique (100% vs. 50%) when supination-flexion failed.

CONCLUSIONS

This study concludes that hyperpronation technique should be used as a first maneuver reduction in treating NE, a simple one-movement technique.

Radial Head Subluxation Among Young Children in the United States Associated With Consumer Products and Recreational Activities

This study investigated the epidemiology of children treated in US emergency departments for radial head subluxation (RHS) associated with consumer products and recreational activities using data from the National Electronic Injury Surveillance System. An estimated 430 766 (95% confidence interval: 341 194-520 339) children ≤5 years of age were treated for RHS in US emergency departments from 1990 to 2011. The mean patient age was 2.1 years, and 56.5% of patients were girls. The most common mechanism of injury was a fall (43.2%), followed by arm pull (39.4%). The annual rate of RHS increased significantly by 190.1% during the 22-year study period. This is the largest study of RHS to date and the first to use a nationally representative sample to investigate secular trends and mechanisms of injury for RHS associated with consumer products and recreational activities. Events associated with consumer products and recreational activities are an important increasing source of RHS.

Investigation on 2331 cases of pulled elbow over the last 10 years

Pulled elbow is a common upper extremity injury in children. We present a retrospective study of 2331 pulled elbow cases examined in our hospital over the last ten years. All pediatric patients with a diagnosis of pulled elbow from January 2002 to December 2011 were retrospectively reviewed according to sex, age, affected arm, recurrence rate, mechanism of injury and treatment outcomes. There is no significant sex difference. The frequency of injury peaked for both boys and girls at 6 months and 2 years of age. The left arm was more affected than the right. The recurrence rate was 14%. In about 50% of cases, the cause of injury was forcible traction to the forearm. Almost all of the splinted patients, caused by severe pain or lack of mobility of the affected limb following reduction, recovered within 2 weeks, but 2 were later diagnosed with a fracture. For infants less than 1 year old, injury can often occur when rolling over. For children 1 year old or older the left arm is more commonly affected, and the frequency of injuries to the left arm increases with age, possibly because the left hand is commonly held by the guardian's dominant right hand and faster development of muscle strength in the child's dominant right arm works toward preventing injury to that arm with age.