Autologous replacement of the head of the radius-proximal fibula versus second metatarsal base: an anatomic feasibility study.

INTRODUCTION: This study investigated the anatomic feasibility of a new surgical therapy option for radial head arthrosis using an autologous vascularized bone graft of the second metatarsal and proximal fibula to recreate the proximal radiohumeral joint. MATERIALS AND METHODS: Upper and lower extremities of eleven body donors were evaluated using CT prior to anatomic dissection. Several distinct anatomic parameters were measured on the ipsi- and contralateral radial and fibular head and the second metatarsal base: bone diameter, articular surface diameter, head height, metaphyseal (neck) diameter, articular surface radius, total articular surface area, and angulation of the articular surfaces (facet). Each dissection phase was photographed in a standardized fashion and all measurements were repeated by direct caliper-measurements. RESULTS: When comparing the proximal radius and fibula to search for anatomic similarities, similar values were found in the maximum articular surface diameter and minimum and maximum measures of the neck diameter. Comparing the proximal radius and the second metatarsal, statistically similar values were found in the maximum neck diameter performing direct measurements and CT evaluation, the maximum head diameter in CT evaluation and the articular facet angulation. CONCLUSIONS: Neither the proximal fibula nor the base of the second metatarsal are ideal bone grafts for replacement of the head of the radius. The base of the second metatarsal might be a bit more suitable as a potential donor since the angulation of the proximal articular facet is similar to that of the radius. LEVEL OF EVIDENCE: Level IV, anatomic study.

Musculoskeletal imaging in neonates: use of ultrasound.

High-resolution US is a practical, cost-effective modality to evaluate the musculoskeletal system in neonates. US can be performed portably in the neonatal intensive care unit so that the critically ill infant can be evaluated with minimal distress. Sonography is noninvasive and does not require sedation; typical questions that might require the use of MRI or CT in older children can be rapidly resolved with US. Dynamic imaging can be used in real time to stress joints and see how articular structures relate. Given the advantages of US within the neonatal population, it has been widely used to evaluate for neonatal fractures, congenital joint abnormalities, limb deficiencies as well as muscular and soft-tissue abnormalities.

Delayed radial head dislocation after radial shaft fracture fixation: a case report and review of the literature.

BACKGROUND: Ipsilateral fracture of the radial shaft with dislocation of the radial head was a rare injury, but a delayed radial head dislocation after radial shaft fracture fixation was more extremely rare. CASE PRESENTATION: A 39-year-old man fell from the height on his outstretched hand and injured his left, non-dominant forearm. Preoperative radiographs demonstrated a comminuted fracture of the proximal third of the radius but with no apparent dislocation of the distal or proximal radioulnar joints or the elbow. Seven days after the injury, the radius was fixed with a reconstruction locking plate, and the immediate postoperative radiograph revealed a satisfactory reduction. However, a radiograph done at the 4th week postoperatively showed that the radial head dislocated. Manual reduction under anesthesia was tried but failed and the patient refused to take another open surgery. The patient had an acceptable range of motion 12 months after the surgery: elbow flexion 120°, full elbow extension, forearm pronation 80°, forearm supination 80°, but he complained the pain around the elbow. CONCLUSION: In the case of radial shaft fracture especially the when occurs at the proximal third of the radial shaft, even if the radiograph does not show the injury of the proximal radioulnar joint, we should also make a thorough examination of the proximal radioulnar joint. If the radial head dislocation is not initially diagnosed or treated late, a delayed dislocation would be very difficult to manage with a poor expected outcome.

Distraction osteogenesis at the proximal third of the ulna for the treatment of Masada type I/IIb deformities in children with hereditary multiple exostoses: a retrospective review of twenty cases.

BACKGROUND: Ulna distraction by monolateral external fixator (MEFix) is a good option for the treatment of Masada type I and IIb deformities in children with hereditary multiple exostoses (HMEs). However, there is no consensus regarding where to perform ulnar osteotomy. Our hypothesis is that osteotomy at the proximal third of the ulna and progressive distraction with MEFix can simultaneously correct elbow and wrist deformities in patients with HME. METHODS: We retrospectively reviewed patients with HME who underwent ulna distraction osteogenesis from June 2014 to March 2019. The carrying angle (CA), radial articular angle (RAA), ulnar variance (UV), radial variance (RV) and range of motion (ROM) of the affected forearm and elbow were clinically assessed before lengthening and at the last follow-up visit. The total ulna lengthening distance (LD) and radiographic outcome were also recorded. RESULTS: Nineteen patients (20 forearms) with HME aged 9.1 ± 2.4 years at the time of surgery were retrospectively reviewed. The mean follow-up period was 26.1 ± 5.6 months. There were 11 patients (12 forearms) with Masada type I deformities and eight patients (8 forearms) with Masada type IIb deformities. Patients with type IIb deformity had higher RV, lower CA values, less elbow flexion and forearm pronosupination than those with type I deformity (p < 0.05); RV was an independent risk factor for radial head dislocation, with the cut off at RV > 15.5 mm. The mean LDs in patients with type I and type IIb deformities were 33.6 ± 6.6 mm and 41.4 ± 5.4 mm, respectively. The mean CA, UV, RV, forearm pronation and ulna deviation at the wrist improved significantly following surgery in all patients. In particular, five of eight patients (62.5%) with type IIb deformities had concentric reduction of the radiocapitellar joint, while no radial head subluxation was detected in patients with type I deformities at the last follow-up. Three complications were recorded: two pin-track infections and one delayed union. CONCLUSIONS: Distraction osteogenesis at the proximal third of the ulna provides satisfactory clinical and radiological outcomes in patients with Masada type I and IIb deformities. Early treatment of Masada type I deformities is indicated before progression to more complex type IIb deformities.

Three new patients with Steel syndrome and a Puerto Rican specific COL27A1 mutation.

Steel syndrome was initially described by H. H. Steel in 1993 in Puerto Rico, at which time he described the clinical findings required for diagnosis. The responsible gene, COL27A1, was identified in 2015 (Gonzaga-Jauregui et al., European Journal of Human Genetics, 2015;23:342-346). Eleven patients have previously been described with Steel syndrome and homozygous COL27A1 mutations, with eight having an apparent founder mutation, p.Gly697Arg. We describe three more patients identified at Einstein Medical Center Philadelphia and St. Christopher's Hospital for Children (Philadelphia, PA) diagnosed with Steel syndrome. All three are of Puerto Rican ancestry with the previously described founder mutation and had either hip dislocations or hip dysplasia. Radial head dislocation was only identified in one patient while short stature and scoliosis were noted in two of these patients. There are now 51 patients in the literature with Steel syndrome, including the 3 patients in this article, and 14 patients with a genetically confirmed Steel syndrome diagnosis.

Isolate and irreducible radial head dislocation in children: a rare case of capsular interposition.

BACKGROUND: Radial head dislocation with no associated lesions, is a relatively uncommon injury in children. In this case report, it is reported a case of anteromedial locked radial head dislocation in children, and we discuss its clinical presentation and pathogenetic mechanism of injury. CASE PRESENTATION: An 8-year-old girl fell off on her right forearm with her right elbow extended in hyperpronation. An isolated radio-capitellar dislocation was identified with no other fractures or neurovascular injuries associated. Elbow presented an extension-flexion arc limited (0°- 90°), and the prono-supination during general anesthesia shows "a sling effect" from maximal pronation (+ 55°) and supination (+ 90°) to neutral position of forearm. The radial head dislocation was impossible to reduce and an open reduction was performed using lateral Kocher approach. The radial head was found "button-holed" through the anterior capsule. The lateral soft tissues were severely disrupted and the annular ligament was not identifiable. Only by cutting the lateral bundle of the capsule was possible to reduce the joint. At 50 moths follow-up, patient presented a complete Range of motion (ROM), complete functionality and no discomfort or instability even during sport activities. DISCUSSION AND CONCLUSION: It is important to understand the pathogenic mechanisms of locked radial head dislocation in children. Some mechanism described are the distal biceps tendon or the brachialis tendon interposition. However even the anterior capsule can hinder reduction. A characteristic "sling-effect" of the forearm could be pathognomonic for capsular button-holing. Surgical release of the capsular bundle sometimes is the only way to reduce the dislocation and obtain a good outcome.

Single-Bone Forearm as a Salvage Procedure in Recalcitrant Pediatric Forearm Pathologies.

PURPOSE: To report on the outcome of single-bone forearm reconstruction (SBFR) as a salvage procedure in pediatric forearm pathologies. METHODS: Twenty-eight forearms in 27 patients (median age, 9.6 years; range, 3.4-29.7 years) treated with SBFR at a pediatric referral center were included in the study. Records and radiographs were retrospectively analyzed. Median follow-up was 84 months (range, 24-261 months). The most common underlying condition was multiple hereditary exostoses (MHEs) (17 of 28), followed by brachial plexus birth injury (5 of 28), Ollier disease (2 of 28), congenital radial head dislocation (2 of 28), and others (2 of 28). RESULTS: By 4 months (range, 2-10 months) after surgery, 21 of 28 forearms had united. Median resting postoperative forearm rotation was 10° pronation (range, neutral to 25° pronation). Before surgery, pain was present in 23 of 28 forearms. At the latest follow-up, pain was present in 5 of 28 forearms. In three of the 5 forearms with residual pain, this was attributed to ulnohumeral degenerative changes that existed prior to SBFR. Following SBFR, elbow flexion-extension range was maintained. In the subgroup with MHEs, radial articular angle was maintained (median, 37°-30°) and carpal slip percentage improved significantly (median, 40%-12%). Complications occurred in 8 forearms: 3 cases of nonunion in older patients (age, 30, 20, and 14 years), 2 cases of traumatic juxtaimplant fractures following successful union, 1 case of infection, 1 case of compartment syndrome, and 1 case of persistent radiocapitellar impingement. All complications were successfully treated. When stratified by age, none of the patients in the younger group (16 forearms, age < 12 years) had nonunions or pain at latest follow-up. CONCLUSIONS: The SBFR is an old, but generally reliable, option as a single-stage salvage procedure for a number of recalcitrant pediatric forearm pathologies. Success rate may be higher in younger patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Monteggia fracture: an easy fracture to miss.

PURPOSE: To assess the incidence of missed Monteggia fracture by radiologists and bedside clinicians (emergency and orthopaedic doctors) at a tertiary hospital. METHODS: A comprehensive search was conducted on Picture Archiving and Communication System (PACS) and electronic medical records (EMR) between Jan 2010 and April 2019. All consecutive paediatric and adult patients who presented to the emergency department with the diagnosis of Monteggia fracture were included. The patient's emergency presentation medical notes and trauma film reports were compared. Most emergency presentations were discussed with orthopaedics; hence, this was combined as a single group (bedside clinician group). All images were blindly reviewed by a senior consultant radiologist. Results from the radiologist and bedside clinician groups were compared. RESULTS: Fifty-one patients were identified; 4 were excluded as they were not true Monteggia fracture on review. Forty-seven patients were included in the study (age range 3-70 years, mean age 15 years). Thirty-three patients (70%) were correctly diagnosed by both groups. Twelve patients (25.5%) had a missed diagnosis by the radiologist's group. Seven patients (14.9%) were missed by the bedside clinicians. Five patients (10.6%) were missed by both groups with fractures detected on re-presentations. The most commonly missed finding was a radial head dislocation/subluxation, followed by a subtle ulnar fracture (confirmed by periosteal reaction development on subsequent radiographs) and an ulnar plastic deformity. CONCLUSION: The Monteggia fracture is an important diagnosis, but it is not infrequently missed by radiologists and clinicians. Special attention to the radiocapitellar joint alignment and ulnar periosteum, and looking for a subtle ulnar fracture or plastic deformity would ensure correct diagnosis.

Long-term follow-up of corrective ulnar osteotomy for missed Monteggia fractures in children.

BACKGROUND: Pediatric Monteggia fractures are relatively rare and are commonly missed. Radial head subluxation can persist with long-term consequences if these fractures are left untreated. We evaluated the long-term treatment outcomes after open reduction with ulnar osteotomy for missed Monteggia fractures during childhood. MATERIALS AND METHODS: Fourteen children were included. Our objective was to assess the clinical and radiographic postoperative outcomes. We evaluated satisfaction by questionnaire. Open reduction of the radial head was performed, combined with an opening-wedge ulnar osteotomy. The mean interval between trauma and surgery was 26.9 months (range, 1-145 months). The mean length of follow-up was 132 months (range, 67-206 months). RESULTS: Only patients with a delay of more than 6 months complained of elbow tenderness. Clinical improvement (except for pronation) was obtained postoperatively, with significance found in the flexion-extension arc (P = .011). In addition, pronation loss (P = .044) and the flexion-extension arc (P = .041) improved significantly in patients with a surgical delay under 6 months compared with patients with a surgical delay of more than 6 months. Radiographically, there were 9 good and 5 fair results. We found a negative association between radiographic outcomes and both age at surgery and delay to surgery (P = .036 and P = .039, respectively). CONCLUSIONS: Good results can be obtained after open reduction with opening-wedge ulnar osteotomy. Lesser clinical and radiographic outcomes can be expected after a surgical delay of more than 6 months. Furthermore, the radiographic outcome seems better if the patient is younger than 6 years.

The treatment of chronic radial head dislocation in Monteggia fracture without annular ligament reconstruction.

INTRODUCTION: The treatment of neglected radial head dislocation after missed Monteggia fracture dislocation in children is a controversial issue. The purpose of this study is to report our clinical experience in the treatment of the condition without annular ligament reconstruction. METHOD: This is a retrospective review of 20 patients between 2008 and 2014. Procedures included open reduction of the radial head and ulnar lengthening angulation osteotomy. In cases of unstable radial head reduction, a trans-capitellar K wire was applied. The pre- and post-operative radiographs were available for evaluation as well as the Mayo Elbow Performance Index (MEPI). RESULTS: The average pre-operative elbow extension-flexion arc was 99.5° and pronation-supination arc was 151°. At last follow-up, the flexion of elbow had significant improvement (from 110° to 124°), while the average pronation and supination arc decreased, most in pronation (from 75° to 65°). Post-operatively, MEPI scored higher, especially in elbow pain and stability. Patients underwent surgery within one year of injury had better functional outcome than those injured over one year. The patients required trans-capitellar K wire for unstable radial head reduction and were in the older age group. At final follow-up, the reduction of radial head was maintained in all cases except two with mild subluxations of the radial head in radiographs. Two cases required radial shaft shortening to facilitate the reduction because of proximal migration of the radius. CONCLUSION: For neglected radial head dislocation following Monteggia fracture dislocation, we presented our surgical strategy to reduce the radial head without annual ligament reconstruction. Our patients functionally benefited from the procedure with significant improvement in elbow pain and stability, as well as improved flexion of the elbow with stable radial head reduction. LEVEL OF EVIDENCE: IV.

Biomechanical study of isolated radial head dislocation.

BACKGROUND: Isolated radial head dislocation is a rare injury with an unclear pathomechanism, and the treatment is controversial. The purpose of the present study was to investigate the biomechanical contributions of the annular ligament, quadrate ligament, interosseous membrane, and annular ligament reconstructions to proximal radioulnar joint stability. METHODS: Five fresh frozen cadaveric upper extremities were amputated above the elbow and solidly fixed on a customized jig. Radial head dislocation was reproduced by sequential sectioning of ligamentous structures and passive mobility testing. Radial head displacement during mobility testing was measured with an electromagnetic tracking device in three forearm rotation positions. The data were compared among different sectioning stages and between two types of simulated ligamentous reconstruction. RESULTS: Lateral displacement of the radial head significantly increased in the neutral forearm rotation after annular ligament sectioning (46 ± 10%, p < 0.05). After quadrate ligament sectioning, we found significant posterior (67 ± 36%, p < 0.05) and lateral (74 ± 24%, p < 0.01) displacement in neutral forearm rotation and pronation. Significant radial head displacement was found in all directions and in all forearm positions after sequential sectioning of the proximal half of the interosseous membrane. Anatomical annular ligament reconstruction stabilized the proximal radioulnar joint except for anterior laxity in neutral forearm rotation (15 ± 6%, p < 0.05). The radial head with Bell Tawse procedure was significantly displaced in all directions. CONCLUSION: The direction of radial head instability varied depending on the degree of soft tissue sectioning and specific forearm rotation. Anterior radial head dislocation may involve more severe ligament damage than other types of dislocation. Anatomical annular ligament reconstruction provided multidirectional radial head stability.

An Evaluation of Forearm Deformities in Hereditary Multiple Exostoses: Factors Associated With Radial Head Dislocation and Comprehensive Classification.

PURPOSE: This study attempted to evaluate a series of patients with hereditary multiple exostoses (HME) who could not be categorized according to the widely accepted Masada classification and to identify radiographic variables such as radial bowing, ulnar shortening, ulnar variance, radial articular angle, and carpal slip predictive of deformity. METHODS: We retrospectively reviewed data on 102 upper limbs of 53 pediatric patients with HME. Demographics, site of forearm involvement, and radiographic parameters were documented. Patients with exostoses of the forearms were categorized into 6 groups based on location of the exostoses and presence or absence of a dislocated radial head. Proportional ulnar shortening was calculated as the ratio of ulnar length to radial length. RESULTS: According to the Masada classification, 4 limbs were normal, 10 were type I, 2 were type II, and 24 were type III. Sixty-six limbs were unclassifiable. We classified those 66 limbs using a modification of the Masada classification. Of the 106 limbs, 11 (10.3%) had a dislocated radial head. Based on the radiographic analysis, patients with proportional ulnar shortening of less than 0.9 had a higher risk of radial head dislocation than did those with proportional ulnar shortening of 0.9 or greater. Patients with radial bowing greater than 8.1% showed a higher frequency of radial head dislocation than did those with radial bowing of 8.1% or less. Exostoses of both the distal radius and ulna tended to increase the rate of radial head dislocation. A greater amount of negative ulnar variance caused more radial bowing and a greater radioarticular angle. CONCLUSIONS: We propose a new comprehensive forearm classification for patients with HME. Proportional ulnar shortening less than 0.9 and radial bowing 8.1% or greater can be used to predict the risk of radial head dislocation. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Radial notch labralization for proximal radioulnar joint dysplasia.

BACKGROUND: Chronic posterior subluxation or dislocation of the radial head is uncommon and difficult to treat. To restore radiocapitellar alignment, procedures such as deepening of the notch using a high-speed burr have been described, but they can result in cartilage damage. We hypothesized that a radial notch labralization using soft tissue could improve radiocapitellar tracking without violating the joint surface. METHODS: A radial notch labralization was performed in 3 patients with chronic posterior subluxation of the radial head and developmental dysplasia of the radial notch in the setting of complex recurrent instability of the elbow. A soft tissue graft (typically a portion of an allograft hamstring tendon) was used to create a meniscus-like bumper posteriorly, thereby deepening the radial notch and reducing its radius of curvature. A corrective anterior opening wedge ulnar osteotomy was also performed to realign the radial head with the capitellum. RESULTS: At a mean follow-up of 32 months, all 3 patients were pain free and had maintained a stable joint, with a functional range of motion. Each patient gave a rating of either "Greatly Improved" or "Almost Normal" on the Summary Outcome Determination scale. Radiographs performed during the last follow-up showed improved radiocapitellar alignment. CONCLUSION: Chronic posterior subluxation or dislocation of the radial head can occur subsequent to developmental joint changes. The radial notch labralization using a soft tissue graft associated with a corrective ulnar osteotomy was successful in restoring radial head stability and avoiding cartilage damage.

Prevalence of Capitellar Osteochondritis Dissecans in Children With Chronic Radial Head Subluxation and Dislocation.

OBJECTIVE: An abnormal radiocapitellar articulation may play a role in the development of capitellar osteochondritis dissecans (OCD). The objective of this study is to determine the prevalence of capitellar OCD in pediatric patients with chronic radial head subluxation (RHS) or radial head dislocation (RHD). MATERIALS AND METHODS: We searched the radiology reports generated at a large pediatric hospital between 2004 and 2012, to identify patients 8-18 years old with chronic RHS or RHD. Patients with underlying bony abnormalities that could obscure, be confused with, or increase the risk of OCD of the elbow were excluded. Two pediatric radiologists assessed images of the elbow, grading radiocapitellar alignment as follows: normal, subluxed, dislocated, or intermittently subluxed and dislocated. Readers also reviewed images to detect capitellar OCD. The differences in the prevalence of OCD noted in elbows in each category of radiocapitellar alignment were assessed. RESULTS: A total of 118 cases of chronic RHS, RHD, or both were detected in 100 patients. The radiocapitellar alignment of these cases was defined as follows: 53-58% were dislocated, 26-31% were subluxed, 14-15% were intermittently subluxed and dislocated, and less than 1% had normal alignment. There were 14 cases of capitellar OCD (11.9%). One elbow with OCD was categorized by both readers as dislocated, with the remaining 13 elbows (93%) deemed by the two readers to be either subluxed or intermittently subluxed and dislocated. The percentage of elbows with RHS that were found to have capitellar OCD was 32.3-33.3%, compared with 1.4-1.6% of elbows with RHD. CONCLUSION: The prevalence of capitellar OCD is greater in elbows with RHS than in those with RHD. This finding suggests that abnormal radiocapitellar mechanics are a factor in the development of OCD. In children with RHS and new or worsening pain, capitellar OCD should be considered, and imaging strategies should be directed toward early identification of this important and treatable condition.

[Radial head anterior dislocation and ulna bowing in children: About 3 cases and review of the literature]. / Luxation antérieure de tête radiale et déformation plastique de l'ulna chez l'enfant: A propos de 3 cas et revue de la littérature.

We present three cases of anterior dislocation of the radial head associated with plastic deformation of the ulna in children. It is a Monteggia equivalent lesion type 1 according to the Bado's classification. Radiological diagnosis often goes unnoticed to the untrained eye. The relationship between the radius and the capitulum identifies the dislocated radial head on radiographs AP or lateral. Line Mubarak highlights the bowing of the ulna on radiographs lateral. Evolution is pejorative in the absence of early orthopedic care. Older is the patient and longer is the time between injury and treatment, less good are the clinical and radiological results. The first line treatment is closed reduction of the dislocation of the radial head and the bowing of the ulna. Surgical treatment is indicated in cases of failure of closed reduction. Adequate surgical treatment is that which allows and maintain the reduction. The surgery is the most possible minimally invasive. Open reduction can be associated with various surgical techniques: the annular ligament plasty, the establishment of a transitory pin intra-articular capitulo radiale, the ulna osteotomy, the radial osteotomy. Radial head resection is not indicated in children.

Nous présentons trois cas de luxation antérieure de tête radiale associée à une déformation plastique de l'ulna chez l'enfant. Il s'agit d'une lésion de Monteggia équivalent type 1 selon la classification de Bado. Le diagnostic radiologique passe souvent inaperçu pour un oeil non averti. L'alignement entre le radius et le capitulum permet d'identifier la luxation de tête radiale sur des radiographies de face ou de profil. La ligne de Mubarak met en évidence la déformation plastique de l'ulna sur des radiographies de profil. L'évolution est péjorative en l'absence d'une prise en charge orthopédique précoce. Plus le patient est âgé et plus le délai entre le traumatisme et le traitement est long, moins les résultats clinique et radiologique sont bons. Le traitement de première ligne est la réduction à foyer fermé de la luxation de tête radiale et de la déformation plastique de l'ulna. Le traitement chirurgical est indiqué en cas d'échec de la réduction à foyer fermé. Le traitement chirurgical adéquat est celui qui permet la réduction et le maintien de celle-ci tout en étant le moins invasif possible. La réduction à foyer ouvert simple peut être associée à diverses techniques chirurgicales : la plastie du ligament annulaire, la mise en place d'une broche intra-articulaire capitulo radiale transitoire, l'ostéotomie ulnaire, l'ostéotomie radiale. La résection de tête radiale n'a pas d'indication chez l'enfant.

Role of the interosseous membrane and annular ligament in stabilizing the proximal radial head.

HYPOTHESIS: The purpose of our study was to determine the relative contributions of the annular ligament, proximal band, central band, and distal band of the interosseous membrane in preventing dislocation of the proximal radius. METHODS: In part 1 of the study, 8 forearms were loaded transversely with the forearm intact, and the central band, proximal band, and annular ligament were sequentially sectioned to determine the percentage contribution of each structure in preventing transverse radial displacement. In part 2, 12 forearms were cyclically supinated and pronated while optical sensors measured radial and ulnar motion. Transverse radial head motion was computed as the distal band, central band, and proximal band (and annular ligament) were sequentially sectioned. RESULTS: In part 1, there was no significant difference in the percentage contribution of each structure in preventing radial transverse displacement. In part 2, only after sectioning of the central band did significant radial head displacement occur. Greater displacements occurred in supination than in pronation. Dislocation of the proximal radius occurred in 2 arms after sectioning of all 3 structures. DISCUSSION: Under pure transverse displacement, the central band, annular ligament, and proximal band equally contributed to stabilizing the radius. However, during forearm rotation, the central band contributed more to radial head stability than the annular ligament and proximal band. Our study contributes to our knowledge of forearm biomechanics, demonstrating the importance of the central band in providing proximal radial head stability. Forceful supination should be avoided after surgical procedures designed to stabilize the radial head.

Isolated lateral radial head dislocation in a child: A case report and literature review.

INTRODUCTION: Radial head dislocations in children can result from congenital anomalies, traumatic events, or as part of more complex injuries like Monteggia fractures. These dislocations are rare and may be overlooked unless considered in differential diagnoses. CASE PRESENTATION: We describe a unique instance of a post-traumatic isolated lateral radial head dislocation in a 5-year-old boy with no previous medical concerns. The child presented with persistent pain and limited mobility in the left elbow following an unwitnessed fall at home. Diagnosis was confirmed via radiographs showing the dislocation without associated fractures. Closed reduction under anesthesia was successfully performed. CLINICAL DISCUSSION: This case underscores the importance of a high index of suspicion and thorough imaging in diagnosing pediatric radial head dislocations. Our discussion includes a review of the literature and the clinical approach for managing such injuries, highlighting the specifics of the closed reduction technique used. CONCLUSION: Isolated lateral radial head dislocations, although rare, can occur and are amenable to closed reduction. This case contributes to the limited reports of such dislocations in pediatric patients, emphasizing the need for awareness and precise management strategies to prevent long-term complications.

Anterior Congenital Radial Head Dislocation in an Adult with Associated Posterior Interosseous Nerve Palsy.

Introduction: Anterior congenital radial head dislocation (CRHD) is a rare abnormality that is less commonly seen in the adult population. Most of the time, adult-onset symptoms are due to the prolonged dislocation of the radiocapitellar joint that has been present since birth. One of the possible complications of having a prolonged radial head dislocation is the presence of neuropathies such as posterior interosseous nerve (PIN) palsy. There has been, however, no literature published regarding the relationship of CRHD with PIN palsy. Case Report: We here report a 66-year-old male incidentally diagnosed with anterior CRHD with concomitant PIN palsy after acquiring a fracture of the lateral humeral condyle. Open reduction internal fixation of the lateral condyle was done along with decompression of the said nerve. PIN palsy was completely recovered 2 months after surgery. Conclusion: Surgeons must be aware that PIN palsies can occur in the presence of a chronic radial head dislocation, even if asymptomatic. Prompt nerve decompression as well as removal of the mechanical block is pertinent to avoid the perilous effects of an irreversible PIN palsy.

Predictors of Radial Head Dislocation in Patients with Multiple Hereditary Exostoses.

Background: Radial head dislocation in patients with multiple hereditary exostoses (MHE) is associated with loss of function and cosmetic problems. The treatment of the deformity with radial head dislocation is difficult and the timing of surgical intervention is important. The aim of this study was to evaluate the factors predictive of radial head dislocation in patients with MHE. Methods: Patients diagnosed with forearm deformity due to MHE between 1995 and 2021 were retrospectively evaluated. Radiographic parameters including radial bow (RB), ulnar bow (UB), total radial bow (TRB), total ulnar bow (TUB), percent ulnar length (PUL), ulnar shortening (US), radial articular angle (RAA), modified Masada classification and irregularity of proximal radioulnar joint (PRUJ) of the dislocated group (group D), that is subluxation or dislocation of the radial head, and the located group (group L) were compared. Results: A total of 18 patients and 25 limbs (5 girls and 13 boys) with a mean age of 10.5 years were included. There were significant differences in TUB (22.8° ± 5.6° vs. 10.7° ± 6.5°), PUL (97.5% ± 5.5% vs. 108.2% ± 7.7%) between group D and group L (p < 0.05). Moreover, irregularity of PRUJ on radiographs was more in group D (p < 0.05). Conclusions: It is possible that appropriate radiographic assessment in relation to radial head dislocation may prevent delayed surgical treatment of forearm deformities in MHE. Level of Evidence: Level IV (Diagnostic).