The use of recombinant morphogenic protein-2(rhBMP-2) in children undergoing revision surgery for persistent non-union.

The purpose of the study was to evaluate the safety and efficacy with the use of BMP-2 for treating persistent non-unions in children with underlying complex conditions. Between October 2006 and November 2010 in our unit, 15 patients were treated with rhBMP-2 to enhance bone union. There were nine females and six males with a mean age of 9.5 years (range 4-15) at time of surgery. Seventy-five per cent of the patients required revision of internal fixation with insertion of rhBMP-2 to the non-union site, and the reminder had freshening of the non-union site with rhBMP-2 application. Patients had undergone a mean of 2 (1-5) operations prior to implantation of rhBMP-2. All the patients in the study group were available for review with mean follow-up of 44 months (range 21-70). The mean time to union was 16 weeks (range 10-28 weeks). No adverse events related to BMP-2 application were noted in our study group. Healing occurred clinically and radiographically in 16 of the 17 sites. Our study demonstrates that BMP-2 enhances healing of the persistent non-unions without any adverse events.

Development and psychometric evaluation of a new measure of pain-related support preferences: the Pain Response Preference Questionnaire.

BACKGROUND: Behavioural conceptualizations of chronic pain posit that solicitous responses to pain behaviours are positively reinforcing and play a role in the development of chronic pain and disability. Recent research suggests that studies investigating this model were likely limited by the use of only a few narrowly defined categories of responses to pain behaviour. A measure of preferences regarding pain-related social support has the potential to improve behavioural models of chronic pain by identifying other potentially reinforcing responses to pain behaviour. OBJECTIVE: The Pain Response Preference Questionnaire (PRPQ) was created to assess preferences regarding pain-related social support. The purpose of the present study was to empirically develop PRPQ scales and examine their psychometric properties. METHODS: A large university student sample (n=487) free of chronic pain completed the 39-item PRPQ. Factor analysis was applied to the data from the present sample to empirically develop PRPQ scales. Using a second student sample (n=87), relationships between the PRPQ scales and theoretically related measures were examined to evaluate the construct validity of the scales. Factor analysis supported four factors that reflected preferences for emotional and instrumental support, assistance in managing pain and emotions, having one's pain ignored, and being encouraged to persist with one's activities. Based on this analysis, scales labelled solicitude, management, suppression and encouragement were created. Correlation analyses supported the construct validity of these scales. CONCLUSIONS: The PRPQ is a psychometrically sound measure of preferences of pain-related social support. Research with clinical samples is needed to further evaluate its psychometric properties and clinical utility.

Magnetic resonance imaging of iron oxide labelled stem cells: applications to tissue engineering based regeneration of the intervertebral disc.

Minimally-invasive monitoring of regeneration in diseased tissue is an important aspect of stem cell therapy. Magnetic resonance imaging (MRI) based tracking of cells labelled with ferumoxides has the potential for non-invasive in vivo detection and longitudinal assessment of implanted cells. Cells labelled with ferumoxides appear as hypointense regions on MR images and thus can be distinguished from the surroundings. Application of this methodology to intervertebral disc degeneration (IVD), and detection of labelled cells implanted into the disc for tissue regeneration was examined. Mesenchymal stem cells labelled with a ferumoxide contrast agent were imaged in vitro to quantitatively characterize the signal intensity loss using MRI relaxation parameters (T1, T2, and T2*). To determine whether labelled cells could be detected within scaffolds suitable for implantation, labelled cells were seeded within both natural and synthetic polymers and imaged using MRI. Labelled cells were loaded within poly(ethylene glycol) hydrogels and imaged in vitro using both MRI and confocal microscopy. Labelled cells were also loaded into fibrin gels, and detected ex vivo within rat IVDs using MRI. Lastly, the effect of ferumoxide labelling on cell viability was investigated. Quantitatively, labelled cells demonstrate the greatest signal intensity loss and contrast on T2*-weighted images. Labelled cells can be detected in both synthetic and natural polymers, and can be distinguished from the native tissue environment of the rat IVD. Finally, labelling does not significantly impair cell viability. Consequently, this technique shows promise as a potential method for in vivo longitudinal tracking of stem cell based regeneration of the IVD.

Revision of Oxford medial unicompartmental knee arthroplasty to total knee arthroplasty - results of a multicentre study.

The advantages of Unicompartmental Knee Replacement (UKR) over Total Knee Replacement (TKR) includes the preservation of soft tissue as well as bone stock, and better function with improved range of motion and more natural gait. It is therefore believed that the revision of failed UKR to TKR is technically easier than revision of failed TKR. In our study we tested this hypothesis by assessing the reconstruction requirements and early clinical and radiological outcome following the revision of UKR to TKR. During a 15-year period 1060 primary Oxford medial UKR procedures were performed at three centres, 36 of which underwent revision to TKR due to aseptic failure. The mean operating time for revision surgery was 113 min. Among the revision prostheses used, 28 were standard TKRs, six were constrained, and two were semi-constrained. Thirty had no intramedullary stems whereas six had intramedullary stems. In 30 cases reconstruction for bone loss was not required whereas metal augmentation was used in two knees, contained peg defects in the femur were filled with cement in two knees and contained keel defects in the tibia were grafted using the bone from revision cuts in two knees. After a mean follow-up of 2 years, the mean 'total knee score' was 86.3 and the mean functional score was 78.5. These findings suggest that the complexity of operation and complications encountered during Oxford medial UKR revision and the clinical outcome compare favorably with those of TKR revision.

Limb lengthening and correction of deformity in the lower limbs of children with osteogenesis imperfecta.

We performed limb lengthening and correction of deformity of nine long bones of the lower limb in six children (mean age, 14.7 years) with osteogenesis imperfecta (OI). All had femoral lengthening and three also had ipsilateral tibial lengthening. Angular deformities were corrected simultaneously. Five limb segments were treated using a monolateral external fixator and four with the Ilizarov frame. In three children, lengthening was done over previously inserted femoral intramedullary rods. The mean lengthening achieved was 6.26 cm (mean healing index, 33.25 days/cm). Significant complications included one deep infection, one fracture of the femur and one anterior angulation deformity of the tibia. The abnormal bone of OI tolerated the external fixators throughout the period of lengthening without any episodes of migration of wires or pins through the soft bone. The regenerate bone formed within the time which is normally expected in limb-lengthening procedures performed for other conditions. We conclude that despite the abnormal bone characteristics, distraction osteogenesis to correct limb-length discrepancy and angular deformity can be performed safely in children with OI.

Erythrophagocytosis in alveolar capillaries of goat lung: ultrastructural properties of blood monocytes.

Glutaraldehyde-perfused lungs of 5 adult male and female goats were prepared for electron microscopy to study the properties of blood monocytes in the alveolar capillaries, with particular reference to intravascular erythrophagocytosis. Ultrastructural evidence is presented that the majority of intravascular monocytes were active in forming large uropods and filipods and were vigorously phagocytic for erythrocytes. Erythrocytes were engulfed intact and subsequently fragmented. The fragments were hemolyzed and eventually converted into ghost erythrocytes and siderosomes. An electron-dense protein coat was consistently seen on the outer surface of the cell membrane of monocytes. Coated pits, endocytosis and some indication of internalization of the surface coat were evident. It is suggested that blood monocytes in the lung undergo a process of maturation to differentiate into active phagocytes as immediate precursors of alveolar macrophages.