3D printing an additive manufacturing technique, allowing for rapid prototyping in many industries. To date, medical applications have generally been within a research or industry environment, as the costs (expertise, software and equipment) have been prohibitive.

We have established a means by which 3D printing of bones can be achieved quickly, cost-effectively and accurately from standard computer tomography (CT) digital imaging and communications in medicine (DICOM) data.

CT DICOM data of a malunited forearm fracture were manipulated using open-source software (no cost) and a 3D model was produced by selective-laser-sintering. The entire process took 7 days (total cost £77). This process and the resultant model were then assessed for overall accuracy.

This sequential methodology provides ready and economical access to a technology that is valuable for preoperative templating/rehearsal in complex 3D reconstructive cases.

Rapid prototyping (RP), especially useful in surgical specialities involving critical three-dimensional relationships, has recently become cheaper to access both in terms of file processing and commercially available printing resources.

One potential problem has been the accuracy of models generated. We performed computed tomography on a cadaveric human patella followed by data conversion using open source software through to selective-laser-sintering of a polyamide model, to allow comparative morphometric measurements (bone v. model) using vernier calipers. Statistical testing was with Student's t-test.

No significant differences in the dimensional measurements could be demonstrated. These data provide us with optimism as to the accuracy of the technology, and the feasibility of using RP cheaply to generate appropriate models for operative rehearsal of intricate orthopaedic procedures.

Pelvic fractures in children are uncommon. Despite their potentially serious nature, there is little information in the literature regarding their epidemiology.

We performed a retrospective review of case notes and radiographs, if available, of all patients admitted with bony pelvic injuries to our unit over a 28 year period (1980-2008). Sixty-four children with pelvic fractures were identified (median age 8 years, 75% male). 58% were pedestrians involved in road traffic accidents (RTA), 19% were caused by a fall from a height and 8% were crush injuries. There was seasonal variability, with a 50% increase in pelvic injuries in Autumn and 33% decrease in Winter - compared to Spring/Summer months (in contrast to the peak in overall fracture incidence in the Summer). Median length of stay was 8 days (range 1-180), 11% requiring direct admission to ITU and 5% to HDU. There is a high incidence of associated major injuries - for Stable fractures 52%, Partially stable fractures 60% and Unstable fractures 100%. Five required surgery to the bony pelvis, and 6 for-non pelvic orthopaedic injury. 3 required operative intervention from other specialities, 1 urological repair, 1 laparotomy and 1 lobectomy.

Pelvic fractures in children are potentially serious injuries with a high proportion of major associated injuries. Multiple injuries were sustained in 55% of pedestrian/RTA accidents, 100% of crush injuries and 58% of falls from a height. In this series, 52% of “Stable” pelvic injuries were associated with other major injuries. All paediatric pelvic injuries, even stable pubic rami fractures should be approached with caution, full ATLS assessment and close monitoring.

Articular cartilage is attached to subchondral bone but it is not clear whether the tissues interact and influence in situ (within the matrix) chondrocyte survival. The aim of this study was to determine whether subchondral bone influences in situ chondrocyte survival.

Articular cartilage explants harvested from the meta-carpophalangeal joints (N=6) of three-year old cows were placed into three groups:

subchondral bone excised from articular cartilage (Group A)

Explants were cultured in serum-free media over 7 days. Using confocal laser scanning microscopy, fluorescent probes and biochemical assays, in situ chondrocyte viability and biophysical parameters (cartilage thickness, cell density, culture medium composition) were quantified over time (2.5 hours vs. 7 days) for Groups A, B and C.

With excision of subchondral bone from articular cartilage (Group A), there was a marked increase in chondrocyte death over 7 days primarily within the superficial zone (p< 0.05). There was no significant increase in chondrocyte death within the superficial zone over the same time period for Groups B and C (p> 0.05). There was no significant difference in cartilage thickness or cell density between Groups A, B and C (p> 0.05). Corresponding increases in the protein content of the culture media for Groups B and C but not for Group A, suggested that the release of soluble factors from subchondral bone may have influenced chondrocyte survival.

Subchondral bone significantly influences chondrocyte survival in articular cartilage in vitro. These data support the concept of a functional bone-cartilage system in vivo.

Introduction: Langerhans Cell Histiocytosis (LCH) is a tumour-like condition that runs a variable clinical course. Recent series1,2 have suggested that skeletally immature patients with a solitary bony focus (eosinophilic granuloma) have an especially good prognosis.

Aim: To compare recurrence/progression rates for Scottish patients with solitary eosinophilic granulomas, according to skeletal maturity.

Methods: Retrospective case note review of patients identified from the Scottish Bone Tumour Registry.

Results: We identified 70 cases of biopsy-proven non-spinal eosinophilic granuloma of bone. Of these, 39 were skeletally immature (< 16 years) and 31 were skeletally mature (> 16 years). Follow-up (mean 8.25 years) was either continuing or to discharge/death. On the basis of initial screening (skeletal survey/bone scan), 9 cases (13 %; 4 and 5 patients, from the paediatric and adult groups respectively) were found to have multi-focal disease. Considering those with unifocal disease:

in the immature group, 6 patients (ex 35; 17%) developed a further manifestation of the condition (2 had recurrences at same site; 2 developed a distinct focus in bone; 1 developed a distinct soft tissue lesion causing spinal cord compression; 1 developed diabetes insipidus),

Conclusions: For this population, these data show that the prognosis for paediatric patients with isolated eosinophilic granuloma of bone must be more guarded than that suggested by other series1,2.