Olecranon fractures in children and adolescents: outcomes based on fracture fixation.

PURPOSE: Open reduction and internal fixation with a tension band construct is the standard treatment for displaced transverse intra-articular olecranon fractures. The purpose of this study is to describe the outcomes of tension band fixation of olecranon fractures in children, specifically assessing the need for revision fixation and hardware removal. METHODS: Patients less than 18 years of age diagnosed with a displaced transverse intra-articular olecranon fracture and treated with tension band fixation between 2008 and 2017 were retrospectively enrolled. Operative treatment was with tension band wire (TBW) or tension band suture (TBS) constructs. RESULTS: A total of 46 patients, 36 male and ten female with a mean age of 12.3 years (6 to 17), were included. Surgical fixation was with TBW in 17 patients and TBS in 29 patients. Revision fixation due to failure and fracture displacement was required in 6% of the TBW group and 14% of the TBS group (p = 0.19). The patients who required revision fixation in the TBS group were older (14.7 years versus 11.6 years, p = 0.05) and heavier (70.5 kg versus 48.5 kg, p = 0.05) than those in the same group who did not require revision fixation. CONCLUSION: Paediatric olecranon fractures treated with TBW or TBS fixation unite in the majority of patients with similar need for hardware removal due to prominence and/or pain between fixation techniques. In a select group of older patients weighing greater than 50 kg, TBS constructs demonstrate increased failure rates, requiring revision fixation, and should be avoided in this population group. LEVEL OF EVIDENCE: IV.

Incidence of anterior interosseous nerve palsy in supracondylar humerus fractures in children.

A retrospective review of 101 supracondylar humerus fractures in children between the ages of 0 and 11 years identified 15 patients with neural lesions. All were associated with displaced fractures, and 10 (66%) required open reduction for definitive fracture management. Six of these lesions were isolated anterior interosseous nerve palsies and four other patients had an anterior interosseous nerve injury in combination with another nerve injury, producing a sensory deficit. Two patients had a complete median nerve palsy. Only three patients had nerve lesions that did not involve the anterior interosseous nerve. The incidence (15%) of neural lesions in this study is similar to that reported elsewhere, but the incidence of anterior interosseous nerve lesions, particularly those occurring as an isolated injury, is much higher than has been reported previously. Because an anterior interosseous nerve palsy results in motor loss only, this injury may be easily overlooked.

Short segment transpedicular Cotrel-Dubousset instrumentation: a porcine corpectomy model.

This study examines changes in stiffness in a three-level spinal construct utilizing transpedicular Cotrel-Dubousset instrumentation. In addition, we evaluated the effect of adding offset laminar hooks at the same level as the superior transpedicular fixation. Porcine lumbar spines (L-1 to L-5) were tested as: (a) intact spine, (b) intact spine with instrumentation, and (c) instrumented spine after L-3 corpectomy. Instrumented constructs were tested with and without laminar hooks placed at the level of superior transpedicular fixation. Constructs were tested in modes of axial compression and torsion in a MTS materials testing machine. The fully instrumented intact spines demonstrated a 28.0% stiffness increase over the intact spines in torsion (p < 0.005) and a 23.1% increase in the mode of axial compression (p < 0.0002). There was no statistically significant difference in axial or torsional stiffness in the instrumented intact spine constructs when hooks were added. In the corpectomy model, addition of the laminar hooks increased stiffness in axial compression an average of 26.9% (p < 0.002) and in torsion an average of 28.1% (p < 0.0005). This increase in stiffness may aid in preventing the postoperative progression of kyphosis noted in studies utilizing similar constructs in clinical application for the treatment of lumbar burst fractures.

Segmental fixation of lumbar burst fractures with Cotrel-Dubousset instrumentation.

A retrospective review of 17 patients who underwent bilateral transpedicular decompression, instrumentation with a Cotrel-Dubousset construct, and posterolateral fusion with iliac crest bone graft for treatment of lumbar burst fracture is presented. All patients were followed to fusion with an average follow-up of 18.9 months. Fifteen of sixteen patients returned to preinjury occupation and/or activity. All patients reported good to excellent clinical results. The average postoperative progression of kyphosis was 11.9 degrees. There was no significant change in anterior vertebral height between the preoperative and postoperative periods. We conclude that although excellent early clinical results can be obtained using this operative strategy, the long-term effect of residual kyphosis at the fracture site is unknown.

Comparison of closed reduction and percutaneous pinning versus open reduction and percutaneous pinning in displaced supracondylar fractures of the humerus in children.

A retrospective review of 29 children with displaced supracondylar humerus fractures was performed. Fifteen patients treated with closed reduction and percutaneous pinning and 14 patients treated with open reduction and percutaneous pinning were evaluated at a minimum of 18 months (range 18-80 months). Results were graded according to the criteria of Flynn et al. (Flynn JC, Matthews JG, Benoit RL: Blind pinning of displaced supracondylar fractures of the humerus in children. J Bone Joint Surg [Am] 56:263-272, 1974) using both cosmetic and functional evaluations. Excellent or good results were obtained in 14 of the 15 fractures treated with closed reduction and percutaneous pinning and in 12 of the 14 fractures treated with open reduction and percutaneous pinning. The three fair cosmetic results were associated with inadequate reduction and residual medial angulation. Ten to 15 degrees of motion loss occurred in three older patients. One patient in each group had a minor pintract infection. There were no cases of iatrogenic nerve injury or myositis ossificans. The treatment goal in displaced supracondylar humerus fractures in children is anatomic reduction. If an anatomic reduction cannot be achieved with closed reduction, open reduction is indicated. This can be done without an increased risk of complications.

Circumferential fusion for the management of acute cervical spine trauma.

Combined, single-stage anterior and posterior approaches for acute surgical management of cervical spine injury allows for early restoration of anatomic alignment and decompression. Six patients underwent single-stage anterior decompression and posterior instrumentation and fusion at Vanderbilt University Medical Center between 1984-1989. There was no late deformity. Five patients had incomplete neurologic deficits, and each improved a minimum of one Frankel classification. One patient had complete neurologic deficit at the C5 level. The procedure is lengthy, with an average time under anesthesia of 7.7 hs. Since this procedure allows for immediate mobilization, it should be considered for the management of cervical spine fractures with both anterior and posterior column instability.

Flexion-distraction injuries to the lumbar spine associated with abdominal injuries.

Flexion-distraction injuries to the lumbar spine frequently occur with concomitant abdominal viscus injury. We encountered 16 patients with flexion-distraction lumbar spine injuries. Half of them also suffered abdominal viscus rupture. Lap safety belts were most frequently associated with these injuries; however, the incorrect, underarm use of the shoulder harness was common in our series. The diagnosis of the spinal injury was frequently delayed when abdominal viscus injury occurred together with a flexion-distraction spinal injury. Thorough physical and radiographic examination of the spine as well as a detailed history, including seat belt use, is necessary to diagnose these injuries properly.

An unusual appearance of an aneurysmal bone cyst of the thoracic spine.

Aneurysmal bone cysts (ABCs) have been reported in essentially every bone of the human skeleton. This case report documents a very unusual clinical appearance for this entity: a superior mediastinal mass. Also, the patient underwent multiple imaging studies that demonstrated both common (absence of septations) and unusual (extensive involvement of vertebral body with little involvement of posterior elements) characteristics of ABCs.

A biomechanical study of human lateral ankle ligaments and autogenous reconstructive grafts.

The purpose of this study was to investigate the biomechanical behavior of human anterior talofibular and calcaneofibular ligaments, as well as peroneus brevis, split peroneus brevis, and toe extensor tendon grafts. This article represents the first published data comparing the most frequently injured ankle ligaments to the most commonly used autogenous reconstructive grafts. Twenty fresh human ankles provided the bone-ligament-bone and tendon graft specimens for biomechanical testing on a Minneapolis Testing System. Protocol consisted of cyclic loading at physiologic deflections, followed by several load-deflection tests at varying velocities, followed by a final extremely rapid load to failure test. The load-deflection data for all ligaments and tendons demonstrated nonlinearity and strain rate dependence. The maximum load to failure for the anterior talofibular ligament was the lowest of all specimens tested, while its strain to failure was the highest. The loads to failure of the peroneus brevis and split peroneus tendons were significantly greater than the anterior talofibular ligament and approximately equal to the calcaneofibular ligament. Strains to failure for all tendons were significantly less than ligament strains. The high strain to failure of the anterior talofibular ligament demonstrates its physiologic function of allowing increased ankle plantar flexion-internal rotation, while its low load to failure shows its propensity for injury. The greater strength of the tendon grafts explains the success of most reconstructive procedures in reestablishing stability in chronic ankle sprains; at the same time, the data presented suggest that those surgical procedures sacrificing the entire peroneus brevis tendon are unnecessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical characteristics of human ankle ligaments.

The purpose of this study was to define the biomechanical characteristics of the isolated, individual bone-ligament-bone complexes of the human ankle. Twenty human ankles were dissected of all soft tissues to leave only the tibia, fibula, talus, and calcaneus with their intact anterior talofibular, calcaneofibular, posterior talofibular, and deep deltoid ligaments. Specimens were mounted and tested in a Minneapolis Testing System. Protocol consisted of cyclic loading of each isolated bone-ligament-bone preparation, followed by several constant velocity load-deflection tests at varying deflection rates, followed by a final, extremely rapid load to failure test. All ligaments exhibited nonlinearity and strain rate dependence in their load-deflection data. These properties were correlated with ligament function and trauma. The anterior talofibular ligament, the most commonly injured ankle ligament, had the lowest mean maximum load of the specimens tested, whereas the deep deltoid ligament, the least frequently completely disrupted ankle ligament, had the highest load to failure.

The rate of adhesion of melanoma cells onto nonionic polymer surfaces.

The rates of adhesion of melanoma cells (carcinogenic) onto nonionic polymer surfaces were studied by using radioactively labeled cells and measuring the fraction of cells which adhered to the surface in a given time. Glow discharge (plasma) polymerization of 1,1,3,3-tetramethyldisiloxane and of nitrogen-acetylene-water (mole ratio 0.4:1.0:0.2) was used to modify the surface energy of the substrate. The cell adhesion rate was found to be given by Y = 1 - exp [-k0(gammas - gamma0)t], where Y is the fraction of cells adhered, -k0 is a characteristic rate constant, gammas is the total surface energy of the substrate, gamma0 is the threshold surface energy of cell adhesion, and t is time.

Ultrathin coating by plasma polymerization applied to corneal contact lens.

Plasma coating (deposition of polymer under the influence of plasma) is utilized to modify the surface properties of corneal contact lens. An ultrathin layer (thickness of roughly 200 A) of plasma polymer of acetylene/H20/N2 is applied to poly(methyl methacrylate) (PMMA) corneal contact lenses. The surface becomes highly wettable with water compared to uncoated lens. When coated and uncoated contact lenses are placed on rabbit eyes, a remarkable difference in accumulation of mucous matter is observed. With the control lenses, the accumulation of mucous matter in a week is sufficient to affect the optical clarity of the lenses, whereas the coated lenses show no change after three months continuous wearing. The comparative degree of adhesion of the corneal epithelium cells onto glass, modified glass, PMMA, and coated PMMA surfaces is studied using tissue cultures and phase contrast microscopy. The coated PMMA surface exhibits a degree of tissue adhesion lower than that of control PMMA and higher than that of glass surface, and no sign of toxicity of the coated surface is observed by the tissue cultures.