Bioabsorbable pins for bone fixation in the less invasive innominate osteotomy.

For the less invasive innominate osteotomy for the treatment of developmental dysplasia of the hip, we aim to report radiological outcomes, complication rates and reoperation rates for patients whose bone grafts were secured using bioabsorbable pins. A retrospective study of all patients who underwent less invasive innominate osteotomy for persistent or delayed diagnosis developmental dysplasia of the hip over a period of 2 years from 2008 to 2010 was carried out. A total of 59 hips were identified as having had their bone graft secured with two bioabsorbable pins made from copolymers of L-lactic acid, D-lactic acid and trimethylene carbonate. The average angular correction of the acetabular index in the bioabsorbable group at late follow-up was 16.48° (P<0.0001). Seven percent of patients from the bioabsorbable pin group went on to require reoperation for persistent dysplasia. No patient required reoperation due to implant failure. There was no incidence of postoperative wound infection or other complication requiring medical or surgical intervention. These results demonstrate that the use of bioabsorbable pins to secure the bone graft is as effective and safe as metal fixation.

Correlation of an induced rotation model with the clinical categorisation of scoliotic deformity--a possible platform for prediction of scoliosis progression.

AIM: The primary aims were to develop a simplified three-dimensional model of the thoracolumbar spine and to predict the influence of axial rotation at different levels of the spine on the resultant scoliotic curve, using King's classification as a comparator. MATERIALS AND METHODS: A three-dimensional mathematical model of the simplified thoracolumbar spine (constant size vertebral body without posterior elements) was developed using anatomical data from the published literature. The influence of rotational displacement of the motion segments at various levels of the spine was studied by applying different axial rotations, using a three-dimensional homogeneous transformation matrix method. RESULTS: The result of the model show the correlation of the deformity in lower regions of the spine (lumbar) with the geometrical changes in upper regions of the spine (thoracic), associated with the continuous alteration in direction of the vertebral axis of rotation along the spine. The final curvature of the scoliotic spine is influenced by both the degree of axial rotation in each region and the spatial deformation of the spine (e.g. kyphotic shape and extent of lateral deformity). Qualitatively, the model is capable of producing different categories of the spinal deformity based on King's classification. CONCLUSION: A three-dimensional analysis of spinal shape demonstrates the important relationship between induced vertebral rotation and the resulting deformity. The effect of rotational displacement on the overall configuration of thoracolumbar spine during juvenile growth was assessed and demonstrates close correlation with deformities of the lower regions of spine.

Juxtaposition artefact in a forearm radiograph: a cautionary note in the interpretation of a multiply exposed radiographic plate.

This case report outlines the risks associated with double plate exposure radiographs in follow up images of a child's forearm fracture. Protocols need to be established between radiology and orthopaedic departments for adequate imaging techniques of children's forearms.

Modelling of annulus fibrosus imbalance as an aetiological factor in adolescent idiopathic scoliosis.

OBJECTIVE: To assess and model the influence of collagen fibre imbalance within the annulus fibrosus on the initiation and progression of adolescent idiopathic scoliosis deformity. BACKGROUND: A number of aetiological factors have been proposed for idiopathic scoliosis, including a contribution from the intervertebral disc. The specific influence of the annulus fibrosus has yet to be effectively modelled. METHODS: A mathematical model was used to determine the contribution of collagen fibre orientation and directional imbalance within the annulus fibrosus to vertebral rotation and overall deformity of thoracic spine. Rotations, due to collagen fibre imbalance, and translations, due to rapid growth, were applied to a simplified model of the thoracic spine, using a three-dimensional transformation matrix approach. RESULTS: The ratio of clockwise to anti-clockwise fibres in the intervertebral disc (from unity to 0.80) influenced the induced rotation. The three-dimensional model illustrates the initiation and progression of the scoliotic deformity during adolescent growth, being most obvious at larger growth rates. CONCLUSIONS: Imbalance in the ratio of clockwise and anti-clockwise collagen fibres within the annulus fibrosus has been demonstrated to have the potential to contribute to the progression of scoliosis. For a given fibre ratio, the rate of growth does not influence the induced rotation, but directly influences the severity of the resulting deformity. RELEVANCE: The model defines the potential contribution of collagen fibre imbalance to adolescent idiopathic scoliosis, supporting the clinical observation that greatest progression of deformity occurs during phases of rapid adolescent growth. However, the underlying mechanism is within the annulus fibrosus, assisting in the search for the responsible genes.

Triple pelvic osteotomy in Legg-Calvé-Perthes disease using a single anterolateral incision.

Pelvic osteotomy has a small role to play in the management of Legg-Calvé-Perthes disease. Residual acetabular dysplasia or incongruity can be corrected by rotational acetabuloplasty. In skeletally immature patients this can be performed by complete or incomplete innominate osteotomies. We present the case of a 12-year-old child with residual acetabular dysplasia, resulting from Legg-Calvé-Perthes disease, which was treated by a triple pelvic osteotomy performed by a small single anterolateral incision.

Impact of dedicated skate parks on the severity and incidence of skateboard- and rollerblade-related pediatric fractures.

Dedicated skate parks have led to an increase in pediatric fractures referred to the authors' unit. The authors performed a prospective analysis of all patients presenting to their unit with fractures sustained while Rollerblading or skateboarding over a 5-month period. Epidemiologic data, user experience, wearing of protective gear, place of injury, and mechanism of injury were collected. Fracture type and its treatment were also recorded. The findings indicated that the use of skate parks is associated with a significant increase in the severity of fracture. This was not related to mean length of experience, age, or sex. The use of skate parks had an increased relative risk of 8.35 for fractures requiring manipulation or invasive orthopedic treatment. Only 5% of children were wearing some form of limb/joint protective gear. The authors believe there should be closer supervision and training of children and more emphasis on limb protective gear. The current high incidence of significant skate park injuries will otherwise continue, with implications for the well-being of these children and the burden on the healthcare system.

Spontaneous production of monocyte chemoattractant protein-1 and interleukin-8 by the human lumbar intervertebral disc.

STUDY DESIGN: Scoliotic and herniated human intervertebral disc tissue obtained intraoperatively was cultured, and the medium was analyzed for the production of monocyte chemoattractant protein-1 and interleukin-8. OBJECTIVES: This study was conducted to determine whether the human intervertebral disc is capable of spontaneous production of the chemokines monocyte chemoattractant protein-1 and interleukin-8. SUMMARY OF BACKGROUND DATA: Lumbar disc herniations undergo spontaneous regression with time. This is believed to occur via macrophage-mediated phagocytosis of herniated disc material. Monocyte chemoattractant protein-1, a chemotactic agent for macrophages, has recently been identified in rat intervertebral disc tissue. METHODS: Disc material obtained from patients undergoing surgery for scoliosis and sciatica was cultured using a serumless technique, and the medium was subsequently analyzed for levels of monocyte chemoattractant protein-1 and interleukin-8. RESULTS: Monocyte chemoattractant protein-1 and IL-8 were detected in both control and herniated disc specimens. Noncontained herniations produced higher levels of chemokines than those with an intact anulus. CONCLUSIONS: Human intervertebral disc tissue is capable of spontaneously producing the proinflammatory chemokines monocyte chemoattractant protein-1 and interleukin-8. These are chemotactic for macrophages and capillaries and may explain the ingrowth of granulation tissue seen in spontaneous disc herniation resorption.