Magnetic Resonance Imaging Manifestations of Annular Ligament Injuries in Children With Monteggia Fractures.

BACKGROUND: Magnetic resonance imaging (MRI) is commonly performed in children with elbow injuries to visualize soft tissues such as the annular ligament. Herein, we investigated the MRI manifestations of annular ligament injuries in children with Monteggia fractures following attempted closed reduction. METHODS: The clinical and imaging data of 88 children with acute Monteggia fractures treated at our hospital between 2015 and 2019 were analyzed. Clinically and radiographically, 67 patients achieved radiologic reduction of the radial head at the time of MRI, whereas 21 patients had a failed closed reduction. Annular ligament injury and superior radioulnar joint congruency were analyzed qualitatively, and the maximum superior radioulnar joint gap distance was measured. RESULTS: MRI manifestations of annular ligament injury were primarily characterized as varying degrees of annular ligament displacement, as follows: I degree (10 patients), the annular ligament encircled the radial head without displacement; II degree (5 patients), the annular ligament was partially displaced but visibly encircled the radial head at the level of the radial notch; and III degree (73 patients), the annular ligament was completely displaced. In 15 patients with I and II degrees annular ligament injuries, the annular ligament encircled the radial head (maximum superior radioulnar joint gap distance, 1.2±0.3 mm), showing good congruency of the superior radioulnar joint. In 73 patients with III degree annular ligament injury, the annular ligament was displaced and did not encircle the radial head (maximum superior radioulnar joint gap distance, 3.3±2.7 mm; P <0.05), showing good congruency of the superior radioulnar joint in 25 of 73 patients, and significantly poor congruency in 48 of 73 patients ( P <0.05). CONCLUSIONS: Annular ligament injuries in children with Monteggia fractures exhibit different degrees of displacement of the annular ligament. In I and II degree annular ligament injuries, the annular ligament still encircles the radial head. In III degree annular ligament injuries, the annular ligament is displaced away and is no longer around the radial head. Without the annular ligament restraining the radial head, the superior radioulnar joint is more likely to exhibit poor congruency and increased gap distance. LEVEL OF EVIDENCE: Level II.

Irreducible anteromedial radial head dislocation without fracture caused by transposed biceps tendon in an adult: A case report and literature review.

Irreducible anteromedial radial head dislocation (IARHD) caused by transposed biceps tendon is rare. Delayed diagnosis and surgical failure often occur. A 46-year-old fisherman presented with 10 days history of painful swelling and restricted movement of his right elbow due to strangulation injury by a fishing boat cable. On examination, the images of right elbow reveals in a "semi-extended and pronated" elastic fixation position. Radiography and three-dimensional reconstruction CT reveals an isolated anteromedial radial head dislocation with extreme protonation of the radius and the bicipital tuberosity towards the posterior aspect of the elbow joint, and MRI shows biceps tendon wrapping around the radial neck, similar to umbilical cord wrapping seen in newborns. The Henry approach was applied for the first time to reduce the biceps tendon. The patient achieved a good functional recovery at 26 months, which represents the first reported case of IARHD without fracture caused by biceps tendon in an adult. In treatment of IARHD, attention should be paid to the phenomenon of biceps tendon transposition. Careful clinical examination, comprehensive imaging modalities, and appropriate surgical approach are the keys to successful management.

[Application of annular ligament reposition and repair via Henry's approach for Monteggia fracture in children].

OBJECTIVE: To explore the effectiveness of annular ligament reposition and repair via Henry's approach for Monteggia fracture in children. METHODS: A clinical data of 21 children with Monteggia fractures was retrospectively analysed, who underwent open reduction of the radial head and annular ligament reposition and repair via Henry's approach between May 2015 and July 2019. There were 11 boys and 10 girls with an average age of 8 years and 1 month (range, 4 years and 5 months to 14 years and 4 months). The fracture was caused by falling in 17 cases and by falling from height in 4 cases. There were 16 fresh fractures and 5 old fractures. The Monteggia fractures were rated as Bado typeⅠin 14 cases and Bado type Ⅲ in 7 cases. Preoperative MRI examination and intraoperative observation confirmed that the annular ligament was intact. After operation, the fracture healing, elbow range of motion (ROM), and complications were recorded, and the effectiveness was evaluated according to the Mackay's function scoring system. RESULTS: The incisions healed by first intention after operation, and there was no complication such as radial nerve injury. All children were followed up 12-25 months, with an average of 15 months. No dislocation or subluxation of the radial head occurred after operation. At last follow-up, the ROM of elbow flexion and extension of the children with old fractures increased from (92.6±11.2)° before operation to (123.6±11.6)°, and the ROM of forearm rotation from (96.8±11.8)° to (129.8±5.9)°; the differences between pre- and post-operation were significant ( t=7.672, P=0.002; t=9.487, P=0.001); the ROM of elbow flexion and extension of the children with fresh fractures was 139°-156° (mean, 145°); the ROM of forearm rotation was 158°-168° (mean, 162°). According to Mackay's criteria, 17 cases were excellent and 4 cases were good, with an excellent and good rate of 100%. X-ray film examination showed no nonunion, heterotopic ossification, or loosening of internal fixation after operation. The ulnar fracture and the ulnar osteotomy healed in all cases. CONCLUSION: The annular ligament in Monteggia fractures in children is intact. Compared with the reconstruction of the annular ligament, the reposition and repair of the annular ligament via Henry's approach is closer to the original anatomical state of the annular ligament and has the advantages of less trauma and fewer complications.

Treatment of missed Monteggia fracture with intact annular ligament after an interval of 9 years: a case report and literature review.

OBJECTIVE: Missed Monteggia fractures are commonly observed among children. Both the interval from the injury to surgery and the patient's age at operation are thought to be correlated directly with the success of the surgery and prognosis. The aim of the present work was to report one interesting adult case of a missed Monteggia fracture with an intact annular ligament 9 years after injury and the outcomes at a 7-year follow-up. CASE DESCRIPTION: One missed lesion with a 9-year delay for surgery occurred in a skeletally mature individual, and it was treated by open reduction and ulnar angulation and elongation osteotomy. The annular ligament was interpositioned intact in the radiocapitellar joint, and therefore, instead of the annular ligament reconstruction (ALR), relocation was performed. RESULTS: After one revision surgery for the complication of nonunion, good radiographic and functional outcomes were eventually sustained at the 7-year follow up. CONCLUSION: Good radiographic and functional outcomes can be expected in adult patients in whom the annular ligament is intact and interpositioned, and this was treated by open reduction and ulnar osteotomy 9 years after the initial injury in our patient.

Neuroprotective effect of methylprednisolone combined with placenta-derived mesenchymal stem cell in rabbit model of spinal cord injury.

The aim of this study was to assess the ability of the combination treatment of methylprednisolone (MP) and placenta-derived mesenchymal stem cells (PDMSCs) in a rabbit model of spinal cord injury (SCI). Rabbits were randomly divided into four groups: group 1 (control), group 2 (MP), group 3 (PDMSCs) and group 4 (MP + PDMSCs). In all groups, the spinal cord injury model was created by the weight drop method. Levels of malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were determined by kit. Histopathological examination was also performed. Neurological evaluation was carried out with the Tarlov scoring system. The results showed both MP and PDMSCs had neuroprotective effects, and combining the administration of MP with PDMSCs was shown a significant effect on the recovery of neurological function. Therefore, the combined use of MP and PDMSCs can be used as a potential therapeutic method for SCI.

Biomechanical analysis of the annular ligament in Monteggia fractures using finite element models.

BACKGROUND: The pathogenesis of Monteggia injuries remains controversial. The current study biomechanically explored the pathological changes during Monteggia fractures using finite element analysis. METHODS: Two cadaveric forearm specimens underwent computed tomography in both the prone and supine positions. The images were imported to Mimics to construct three-dimensional images. The obtained models of the annular ligaments were assembled onto the bones. Two thin gaps were produced at the proximal third of the ulna to simulate a Monteggia fracture. The models were analyzed mechanically. The initial fracture process was simulated by constraining the distal portions of the radius and ulna and the dorsal fracture sites of the ulna. The mechanical changes of the annular ligament in the two positions were observed and compared. RESULTS: In the prone position, the maximum Z-axial displacement of the annular ligament was close to that along the Y-axis, although with a significant difference (P < 0.01). In the supine position, the X-axial displacement dramatically increased (P < 0.01), while it was noticeably decreased along the Z-axis (P < 0.01). CONCLUSIONS: Biomechanical changes may partially explain the pathological changes in the annular ligament during Monteggia fractures; longitudinal displacement of the radial head causes it to slip out of the annular ligament while the ligament remains intact.

Mismatch of AO anatomically shaped distal humeral plate with humeral shaft forward flexion angulation in adult Chinese population.

BACKGROUND: LCP extra-articular distal humerus plate (LCPEA) designed by AO has been introduced as an anatomically shaped plate that improves the results of surgical fixation in extra-articular distal humeral shaft fractures. However, no study analyzed whether LCPEA matches humeral shaft forward flexion angulation (FFA). OBJECTIVE: The aims of this study were to evaluate the morphological discrepancies between LCPEA and the humeral shaft FFA in Chinese cadaveric dried adult humeri and to propose a further design of pre-contoured plates to accommodate the FFA. MATERIALS AND METHODS: Forty-four Chinese cadaveric dried adult humeri were used for this study. An eight-hole LCPEA was applied to the posterior aspect of the distal humerus according to the contour. Mismatches between the bone and the plate were recorded. The distance between the inner surface of the plate and the underlying humeral dorsal cortex was measured at the sites of mismatch. The humeral shaft FFA was measured from the intersection angle between tangent lines placed on the dorsal aspect of the 1/3 distal humeral shaft and the dorsal ridge of the 2/3 proximal humeral shaft. The location of the apex of the FFA was determined by measuring the distance from the most distal point of trochlea of humerus to the point of intersection of the FFA tangent lines. The distance was defined as forward flexion distance (FFD). RESULTS: Mismatch was found at the level of proximal 3-6 holes of LCPEA with an average distance of 6.9 ± 3.1 mm (range 2.3-14.0 mm) at the tip of the plate. The FFA was present in all specimens. The average FFA was 8.2° ± 2.2° (range 4°-13°), the average FFD was 99.9 ± 9.6 mm (range 79.2-117.9 mm), and the average ratio of FFD to humerus length was 0.33 ± 0.03 (range 0.27-0.39). CONCLUSIONS: A rather consistent pattern of mismatch was found at the proximal part of LCPEA. An attempt to fit the plate to the bone at this level may cause a gap of the fracture at the opposite cortex. The main reason for the mismatch is the existence of the humeral shaft FFA. LCPEA is usually made a bend of about 8° between the fourth and the fifth dynamic-compression portion of the combination hole in the distal-to-proximal direction.