Availability of global health opportunities in North American Paediatric Orthopaedic Fellowship Programmes.

PURPOSE: Orthopaedic residents are increasingly seeking international health electives (IHEs) during training, many of which involve providing paediatric orthopaedic care. However, little is known about the availability of IHEs during orthopaedic fellowship training. Our study sought to assess the global health opportunities available to North American paediatric orthopaedic fellows. METHODS: We conducted an online, REDCap-based survey of paediatric orthopaedic fellowship programme directors (PDs) in the United States and Canada. The survey link was sent by the Pediatric Orthopaedic Society of North America (POSNA) Evidence-Based Medicine Committee to all POSNA-approved paediatric orthopaedic fellowship PDs. Follow-up reminder emails were delivered at set time intervals. RESULTS: The overall response rate was 55% (26/47). Only three of 26 responding programmes (11.5%) offered a structured global health programme but 42.3% of programmes (11/26) reported fellow IHE participation within the last ten years. In all, 91% of PDs reported that fellows were extremely satisfied with their IHE, and 91% agreed that IHEs are valuable for trainees. Perceived barriers to fellow participation in IHEs included lack of funding, lack of established partner sites, lack of interest among fellows and concerns related to time away compromising clinical/call coverage. In all, 65.4% of PDs agree that IHE participation during training plays a major role in shaping fellows' future volunteer activities. CONCLUSION: There are limited global health opportunities among North American paediatric orthopaedic fellowship programmes, with only 11.5% offering a structured global health programme. Greater efforts to establish sustainable funding and international partnerships may increase opportunities for IHEs during paediatric orthopaedic fellowship training. LEVEL OF EVIDENCE: Level II.

Changes in cell, matrix compartment, and fibrillar collagen volumes between growth-plate zones.

To define the contributions of changes in cell, matrix compartment, and fibrillar collagen volumes to longitudinal bone growth, we measured the differences in cell, pericellular/territorial matrix and interterritorial matrix volumes, and fibrillar collagen concentrations between the upper proliferative and lower hypertrophic zones of the proximal tibial physes of six miniature pigs. The mean numerical density of cells decreased from 110,000 cells/mm3 in the upper proliferative zone to 59,900 cells/mm3 in the lower hypertrophic zone. The mean cell volume increased nearly 5-fold (from 1,174 to 5,530 microm3), and the total matrix volume per cell increased 46% (from 8,040 to 11,760 microm3/cell) between the upper proliferative and lower hypertrophic zones. Both the pericellular/territorial matrix volume per cell and the interterritorial matrix volume per cell increased between the upper proliferative and lower hypertrophic zones; the pericellular/territorial matrix volume per cell increased 61% (from 4,580 to 7,390 microm3/cell), whereas the interterritorial matrix volume per cell increased 26% (from 3,460 to 4,370 microm3/cell). The total increase in mean cell volume of 4,356 microm3 exceeded the total increase in mean matrix volume per cell of 3,720 microm3; the total mean pericellular/territorial matrix volume per cell increased more than the total mean interterritorial matrix volume per cell (2,810 compared with 910 microm3/cell). Fibrillar collagen concentration was greater in the interterritorial matrix than in the pericellular/territorial matrix in both zones and increased in both matrix compartments between the upper proliferative and lower hypertrophic zones. The amount of fibrillar collagen per cell also increased in both matrix compartments between the upper proliferative and lower hypertrophic zones (from 1,720 to 3,100 microm3/cell in the pericellular/territorial matrix and from 1,490 to 2,230 microm3/cell in the interterritorial matrix; thus, the total amount of fibrillar collagen per cell increased from 3,210 to 5,530 microm3/cell). Growth rate was inversely related to the cell numerical density in the upper proliferative and lower hypertrophic zones and was directly related to interterritorial matrix volume per cell in the upper proliferative zone and to pericellular/territorial matrix volume per cell in the lower hypertrophic zone. These results show that cell enlargement contributes more to longitudinal bone growth than does increased matrix volume, that increased pericellular/territorial matrix volume makes a greater contribution to growth than does increased interterritorial matrix volume, and that the total amount of fibrillar collagen per cell increases between the upper proliferative and lower hypertrophic zones. The differences between the two matrix compartments in increase in volume, fibrillar collagen concentration, and amount of fibrillar collagen per cell strongly suggest that they differ not only in matrix organization but in rate of matrix accumulation and assembly and that these differences give the two compartments different roles in skeletal growth.

Spatial distribution of CD44 and hyaluronan in the proximal tibia of the growing rat.

CD44 has been described as a cell surface hyaluronan receptor present on a variety of different cells, and it is generally assumed to be prevalent in most connective tissues that contain hyaluronan. A major aim of this study was to test that presumption by localizing CD44 and hyaluronan within several tissues of the proximal tibia of the growing rat. Comparison of these profiles would reveal whether CD44 and hyaluronan co-localize with high fidelity, as would be expected if CD44 were a major hyaluronan binding protein. Using in situ hybridization and immunohistochemistry, CD44 was identified on osteoclasts, chondroclasts, osteocytes, hematopoietic marrow cells, synovial cells, and connective tissue fibroblasts (ligaments, tendons, and fascia). Although the majority of osteocytes expressed CD44, reduced expression was observed for osteoblasts and ostcoprogenitor cells. Additionally. CD44 was not detected on chondrocytes from epiphyseal and metaphyseal growth cartilages or in meniscal fibrocartilage. Using biotinylated G1 domain from aggrecan and link protein, hyaluronan was observed in the maturational and hypertrophic zones of all growth cartilages, the synovium and other fibroblastic connective tissues, regional areas of the periosteum and endosteum (around osteoblasts, osteoprogenitor cells, and osteoclasts), osteocyte lacunae, and surrounding blood vessels. In regions of co-localization for CD44 and hyaluronan, it seems that CD44 is a likely hyaluronan binding protein in several tissues of the proximal tibia. However, it does not appear to be the predominant hyaluronan binding protein in growing cartilages of the weanling rat.

Spatial and temporal expression of CD44 isoforms in the developing and growing joints of the rat limb.

Hyaluronan is an integral component of proteoglycan-rich extracellular matrices such as hyaline cartilage. Hyaluronan is commonly found in embryonic tissue and is important in the formation of hydrated matrices that allow cellular expansion and migration. Cell surface hyaluronan-binding proteins such as CD44 are presumed to be important in the cellular interactions with hyaluronan in both of these processes. The primary aim of this study was to document the spatial and temporal expressions of CD44 isoforms during the development and growth of the diarthrodial joints of rat limbs. With use of in situ hybridization and immunohistochemistry, the CD44s isoform is selectively identified as localized to a single cell layer on opposing sides of the joint at the first appearance of joint cavitation (on the 18th day of gestation). After joint formation in the neonate, the expression of the CD44s isoform in the cells at the joint surface is lost. These findings suggest that the CD44s isoform has a role in the development of the diarthrodial joint, presumably through interaction with hyaluronan.

Distraction osteogenesis of the lower extremity with use of monolateral external fixation. A study of two hundred and sixty-one femora and tibiae.

We reviewed the results of distraction osteogenesis of 114 femora and 147 tibiae that had been lengthened to treat a variety of diagnoses. The femora had been lengthened an average of eleven centimeters (range, 3.5 to 17.0 centimeters), or 48 per cent (range, 8 to 86 per cent) of the original femoral length. The average total time for the treatment of the femora (use of the fixator and any subsequent immobilization) was 257 days (range, 105 to 420 days). There were 114 complications related to the femoral lengthenings, which led to eighty-seven additional operations. The tibiae were lengthened an average of nine centimeters (range, 3.0 to 15.6 centimeters), or 41 per cent (range, 9 to 100 per cent) of the original tibial length. The average total time for the treatment of the tibiae was 268 days (range, 110 to 497 days). There were 196 complications related to the tibial lengthenings, which led to 219 additional operations. The Achilles tendon was lengthened during or after seventy-three (50 per cent) of the tibial lengthenings. The femoral lengthenings that were performed to treat a limb-length discrepancy were associated with significantly higher rates of complications overall (p = 0.010) and additional operations (p = 0.023) for each percentage of length gained than those that were performed to treat achondroplasia or another skeletal dysplasia. The femoral lengthenings that were performed to treat short stature (of an endocrine or idiopathic etiology) were also associated with higher rates of complications overall and additional operations than those performed to treat skeletal dysplasias, but the rates were lower than those for lengthenings performed to treat limb-length discrepancy. The rate of complications overall associated with femoral lengthening in patients who were fourteen years old or more was significantly higher than that associated with lengthening in patients who were less than fourteen years old (p = 0.047). Femoral lengthening through the metaphysis was associated with significantly higher rates of complications overall (p = 0.031) and additional operations (p = 0.042) for each percentage of length gained than femoral lengthening through the diaphysis. The tibial lengthenings that were performed to treat Turner syndrome and idiopathic short stature were associated with significantly higher rates of complications overall (p = 0.026) and additional operations (p = 0.003) for each percentage of length gained than those performed to treat skeletal dysplasias. The rate of joint-related problems (p = 0.044) and that of additional operations (p = 0.053) after tibial lengthening in patients who were fourteen years old or more were significantly higher than those rates after tibial lengthening in patients who were less than fourteen years old. The site of the tibial osteotomy did not affect the rate of complications or additional operations. The femoral healing indices (in terms of both days per centimeter [p = 0.002] and days for each percentage of length gained [p = 0.019]) were significantly higher in the patients who were fourteen years old or more than in those who were less the fourteen years old. These values could not be used to predict an increase in the complications because of poor bone formation. The results of the present review suggest that the use of healing indices to gauge the final outcome of distraction osteogenesis is questionable; we were unable to discern significance or clinical importance from appropriately adjusted values.

Use of the Milwaukee brace for progressive idiopathic scoliosis.

One hundred and two (92 per cent) of 111 immature patients in whom idiopathic scoliosis had been treated with a Milwaukee brace were followed to determine the effectiveness of the brace in preventing progression of the scoliosis. The average time from cessation of bracing until the latest radiographs were made for the patients who were managed non-operatively was six years and four months. The average progression of the curve, from the time of initial bracing until use of the brace was stopped, in the eighty-eight patients who were included in the statistical analysis was 4 degrees. The curve continued to progress an average of 5 degrees after use of the brace was stopped in the patients who did not have an arthrodesis. Forty-two patients (48 percent) had more than 5 degrees of progression at the time that use of the brace was stopped. Thirty-seven patients (42 per cent) had an operation or a curve of sufficient magnitude to warrant operative intervention. The maximum correction of the Cobb angle in the brace had prognostic importance for progression of the curve. The patients in whom the curve did not progress or who did not need operative intervention had had an average correction of 20 per cent, while the patients who had a failure had had an average correction of 8 per cent. The patients who eventually had the indications for an arthrodesis were on the average, one year younger (eleven years and none months) and had a curve of a larger magnitude at the time of bracing than the patients who did not need an arthrodesis. The findings of this study do not agree with previously reported favorable results with bracing and raise questions about whether the natural history of progressive idiopathic scoliosis is truly altered by use of the Milwaukee brace.

Salvage reconstruction with vascularized fibular strut graft fusion using posterior approach in the treatment of severe spondylolisthesis.

STUDY DESIGN: One case is reported in which a failed anterior fusion for Grade 4 spondylolisthesis was treated with a vascularized fibular strut graft using a posterior approach. OBJECTIVES: To demonstrate the applicability of this technique for salvage cases or patients with systemic conditions that may decrease the success of more standard techniques. SUMMARY OF BACKGROUND DATA: Surgical stabilization of spondylolisthesis through posterior approach with a fibular strut graft has been previously described. A vascularized strut graft can be used in the treatment of spondylolisthesis and may have applicability in those patients with underlying disease that may impair the use of more standard techniques or in salvage reconstruction. METHODS: With the patient under general anesthesia, through a posterior approach S1 and L4 were decompressed. The fibula with its vascularity intact was harvested and anastomosed with the superior gluteal artery and vein. The fibular strut was placed into the space formed by reaming between L5 and S1. Ilial autograft was used to augment the posterior fusion. After the procedure the patient was placed in a hip spica cast. RESULTS: At the 2-year follow-up the patient has incorporation of the graft, with no evidence of fracture and no significant progression of anterior slip. CONCLUSION: A vascularized fibular strut graft is a feasible alternative in the treatment of severe spondylolisthesis. No complications were encountered in the involved patient. Future application may include salvage reconstruction of failed arthrodesis or in individuals with systemic conditions that may impair graft incorporation using more standard techniques.

Forearm and distal radius fractures in children.

Pediatric forearm and distal radius fractures are common injuries. Resultant deformities are usually a product of indirect trauma involving angular loading combined with rotational displacement. Fractures are classified by location, completeness, angular and rotational deformity, and fragment displacement. Successful outcomes are based on restoration of adequate pronation and supination and, to a lesser degree, acceptable cosmesis. When several important concepts are kept in mind, these goals are usually met with conservative treatment by reduction and immobilization. Greenstick fractures are reduced by rotating the forearm such that the palm is directed toward the fracture apex. Complete fractures are manipulated and reduced with traction and rotation; extremities are then immobilized in well-molded plaster casts until healing, which usually takes about 6 weeks. Radiographs should be obtained between 1 and 2 weeks after initial reduction to detect early angulation. In fractures in any level in children less than 9 years of age, complete displacement, 15 degrees of angulation, and 45 degrees of malrotation are acceptable. In children 9 years of age or older, 30 degrees of malrotation is acceptable, with 10 degrees of angulation for proximal fractures and 15 degrees for more distal fractures. Complete bayonet apposition is acceptable, especially for distal radius fractures, as long as angulation does not exceed 20 degrees and 2 years of growth remains. Operative intervention is used when the fracture is open and when acceptable alignment cannot be achieved or maintained. Single-bone intramedullary fixation has proven useful.

Varus derotation osteotomy for the treatment of hip subluxation and dislocation in cerebral palsy: statistical analysis in 73 hips.

The purpose of this study is to review the results of varus osteotomy in patients with cerebral palsy and to determine factors that influence the rates of residual hip displacement. A retrospective chart review of 65 patients who underwent 79 varus osteotomies was performed. Preoperative, postoperative and follow-up radiographs were analyzed for routine radiographic measurements, pelvic obliquity, osteonecrosis (avascular necrosis), joint incongruity or degenerative joint disease. The average follow-up was 5.2 years (range, 1.1-18.4 years). At follow-up, 3 hips were dislocated, 19 were subluxated and 57 were stable (72%). Age at surgery and the degree of preoperative hip displacement had significant effects on outcome. The average age at surgery for initially subluxated hips, which were located at follow-up, was 7.2 years. This was significantly younger (P = 0.008) than initially subluxated hips, which were displaced (10 years of age). Subluxated hips at surgery were also more likely to be located at follow-up than dislocated hips.

Care of the pediatric foot in myelodysplasia.

Foot deformity is present in almost all patients paralyzed by myelomeningocele. This article outlines the pertinent pathoanatomy resulting in differing foot deformities and their effects on normal gait. Treatment of these deformities is discussed, and the most common deformities present for the different levels of paralysis are outlined. Emphasis is placed on surgical and orthotic treatments, which result in functional improvements for the pediatric patient with spina bifida.

Recurrent supracondylar humerus fracture following prior malunion.

In this report, two patients sustained a recurrent supracondylar humerus fracture following malunion of a previous supracondylar humerus fracture. The patients were treated for their first fracture at 5 and 6 years of age, respectively. One underwent open reduction with percutaneous pinning, and the other was treated with closed reduction with casting. Both patients healed in a moderate degree of extension after the first fracture. Two years later, both sustained a second fracture of the supracondylar humerus. Both had closed reduction with percutaneous pinning and went on to heal uneventfully. We speculate that ensuing post-traumatic extension deformity may accentuate a child's tendency for elbow hyperextension. Extension malunion may place the child at increased risk for a second fracture via similar mechanisms of injury.

Pearls and pitfalls of deformity correction and limb lengthening via monolateral external fixation.

In conclusion, monolateral external fixation can be effectively utilized in the management of limb length discrepancy and angular deformity. This manuscript outlines the pertinent theory, application and problems important in these cases. When faced with specific congenital conditions the surgeon is encouraged to reference relevant literature that is more focused than the current paper.

Limb lengthening in Turner syndrome.

We report the results and complications of eight consecutive patients who underwent bilateral tibial lengthenings for dwarfism associated with Turner syndrome. Lengthening was performed via distraction osteogenesis with monolateral external fixation. Tibias were lengthened an average distance of 9.2 centimeters or 33 percent of the original tibial length. The average total treatment time was 268 days. The overall complication rate was 169 percent for each tibia lengthened and each segment required an average of 1.7 additional procedures. Seven cases (44 percent) required Achilles tendon lengthening and nine cases (56 percent) developed angulation before or after fixator removal; six of these segments required corrective osteotomy for axial malalignment. Two cases (12.5 percent) developed distraction site nonunion and required plating and bone grafting. From this series we conclude that tibial lengthening via distraction osteogenesis can be used to treat disproportionate short stature in patients with Turner syndrome. However, the benefit of a cosmetic increase in height may not compensate for the high complication rate. Efforts to determine the psychosocial and functional benefits of limb lengthening in patients with short stature is necessary to determine the true cost-benefit ratio of this procedure.

The coconut condyle: occipital condylar dysplasia causing torticollis and leading to c1 fracture.

In this report we discuss the case of a child who was initially diagnosed at 1 month of age with congenital muscular torticollis. After falling off a slide at 22 months of age, the patient had onset of pain and an abrupt worsening of his torticollis. After a full workup, it was found that the patient had a C1 fracture and a disproportionately large ipsilateral occipital "coconut" condyle. We believe this congenital anomaly to be the cause of his original head tilt and also predisposed him to C1 fracture and worsening head tilt.