Normal acetabular development in developmental dysplasia of the hip (DDH) depends upon early and maintained congruent reduction. Computed tomography is an accepted method for evaluating this and attempts to quantify hip reduction, by various angular and linear measurements, have been reported. The aim of this study was to assess initial CT scans, following open reduction in the older child with DDH, with comparison of outcome to evaluate prognostic value.
In conclusion, despite the significant differences noted between DDH and normal hips they did not predict acetabular development or persistent acetabular dysplasia.
Surgical treatment of complex deformities necessitates a detailed appreciation of the complex three dimensional abnormal anatomies involved. Preoperative planning for these complex cases traditionally involves x-ray and computerised tomography (CT). These modalities offer only two-dimensional images to represent three-dimensional anatomy. Advances in digital imaging have allowed three-dimensional reconstructions to be derived from CT images. These greatly improve understanding of complex deformities, but will never be able to replace the intuitive understanding that is gained by handling a physical model. The Rapid Prototyping technique Selective Laser Sintering (SLS) is used in the industrial setting to manufacture prototype models from Computer Aided Designs (CAD). This technology can be utilised to convert CT images into accurate three-dimensional physical models of the human bony anatomy. We present the use of SLS modelling to aid in the preoperative planning of complex reconstructive surgery in children. Cases include bladder exstrophy, developmental dysplasia of the hip and reconstruction of a complex elbow malunion. The models provide invaluable visual and tactile information to the operating surgeon, accurately demonstrating the abnormal anatomy in an easily comprehensible manner. They allow estimation of the magnitude and degree of corrections necessary and evaluation of bony deficiencies.
Accurate and relevant patient chart notes are a key component in successful patient care. Hospital charts also constitute an important medicolegal record. The key to defensibility of at least 40% of medical claims rests with the quality of the medical records. With this in mind, we decided to assess the quality of chart note keeping in our unit. A retrospective review of fifty randomly chosen charts was performed. A scoring system was devised to audit ten key criteria comprising patient details, admission note, daily progress notes, signature clarity, consent form, operation note, post-operative plan, post-operative x-ray review, specification of right or left side and discharge letter. Members of the orthopaedic surgical staff were then informed of the chart review and the nature and purpose of the study was explained in detail. They were also told that there would be another chart audit at some random time over the following three months. Subsequently, a further fifty charts were assessed using the same criteria and scoring system. Overall, charts scored poorly in the areas of patient details, clarity of signatures, post-operative x-ray review and left-right specification. Criteria that scored satisfactorily included admission note, consent form, operation note, post-operative plan an discharge letter. Meticulous hospital notes are vitally important in the day-to-day management of patients for successful continuity of care and also for protection of the medical staff should any adverse outcomes arise. In this litigious society consultants and junior medical staff need to be reminded of the importance of optimal note keeping.
Traditional osteotomies are posterior or horizontal. A technique of an oblique osteotomy from the sciatic notch to the iliac crest has been developed at Great Ormond Street since 1996, along with a system of external fixation. It is undertaken concurrently with urological reconstruction. The system of external fixation is relatively simple compared with other published work.
Also children with classical exstrophy were divided into 4 groups on the basis of continence. The mean post-operative percent reduction in the amount of the original diastasis was determined for all age groups. Comparison of pubic approximation was made between the two types of post-operative immobilisation
The average improvement in pubic approximation was 37% for the whole series. Chidren who were older at the time of surgery (18–60 months) were found to maintain better correction over time (76%). Children immobilised with an external fixator maintained better closure of the pelvis than those treated with plaster cast alone. (51% and 12.2% respectively). Maintenance of pubic approximation was associated with a higher level of bladder continence. Complications included 3 cases of infection and loosening of the external fixator requiring early removal. There were no neurovascular complications.
It is a reliable operation and the technique is applicable to all age groups.
Initially the Urologist will make an infra-umbilical incision then identify and mobilise the anatomical structures intended for their subsequent reconstruction and repair. This wound is then temporarily closed. The Orthopaedic surgeon will then approach the ilial crest through bilateral oblique incisions made inferior to the anterior superior ilial spine as described for the Salter osteotomy The interval is developed distal to the anterior superior ilial spine after identification and protection of the lateral femoral cutaneous nerve which is taken medially. After the interval between sartorious and tensa fascia lata are identified the iliac apophysis is split and reflected off the inner and outer ilial crests. The exposure may be improved by also developing the interval between rectus femorus and gluteus medius. Each side of the pelvis is exposed sub-periosteally from the iliac crest extending into the sciatic notch. A Gigli saw is then passed through the sciatic notch. The line of the osteotomy is from the posterior part of the sciatic notch extending anteriorly and superiorly to exit the iliac crest 2cm posterior to the anterior superior iliac spine (figure 2). The most anterior 1.5cm of iliac crest from the distal pelvic fragment is trimmed to allow closure of the iliac apophysis after rotation. The size of the half pin utilised is determined by the age of the patient. A baby under 18 months old will have a 3.5mm pin from the AO wrist external fixator frame and an older child over 2 years, a 4.5mm half pin. One half pin is inserted on each side of the pelvis. The half pin is placed in the distal fragment from anterior and lateral to posterior and medial with the tip of the screw just exiting the cortical bone of the medial aspect of the sciatic notch (figure 3a). Consideration of pin placement must take into account rotation of the distal fragment and preventive skin pressure areas. The iliac apophysis is repaired and the skin wounds are closed. The Urologist completes the reconstruction procedure planned via their infra-umbilical approach. The final stage involves the medial and superior rotation of both distal pelvic fragments and subsequent closure of the symphyseal diastasis. This position is maintained with the application of an anterior A-shaped frame from the wrist, AO fixation set in the younger infant or the AO pelvic fixator in the older child (figure 3b). Symphyseal approximation is confirmed intra operatively by palpatation. Bilateral above knee front slabs casts are applied to prevent kicking the hips or knees. The post-operative management involves pin site care on alternate days. The front slab casts are removed at 3 weeks and the anterior A-frame is removed at 6 weeks after union is confirmed on a pelvic radiograph. Depending on the social situation the children may go home during the post-operative period.
Our results, apart from showing the deleterious effects of low nutrient concentrations, also indicate that isolated cells may metabolise differently from cells in the tissue; at low pO2 we observed a fall in lactate production, the opposite effect to that seen in tissue previously. The mechanism for this difference is as yet unknown.
This poster describes the separation of a pair of conjoined twins, aged 3 months. They were joined at the pelvis, shared a common hindgut and each had bladder exstrophy. The operation to separate them, done over a weekend, involved paired teams of anaesthetists, Paediatric Surgeons and Paediatric Urologists and one Orthopaedic Surgeon. The surgeons mobilised and divided the hindgut, giving one twin the distal half and the other the caecum and proximal colon. Two Urologists reconstructed the bladder exstrophies. The orthopaedic contribution was bilateral oblique pelvic osteotomy to allow midline closure, along with extensive hip releases to deal with severe flexion and abduction contractures. Both twins survived and are thriving. They have little neurological impairment in the lower limbs and therefore have great potential to walk.
Introduction: Complications of homologous blood transfusion include transmission of infection and development of antibodies. Autologous pre-donation, acute normo-volaemic haemodilution and cell salvage have been used to reduce the use of homologous transfusions. Surgery for spinal deformities often requires blood transfusion. In February 1999, we started an autologous pre-donation programme for children undergoing spinal deformity surgery. Methods and results: The case records of the first 15 patients who took part in the programme have been scrutinised and data about pre-donation, haemoglobin, pre- and post-operative hameoglobin, blood loss, blood transfusions, use of blood products, and complications related to pre-donation of blood were obtained and analysed. Similar data from case records of 15 patients, who had surgery for spinal deformities before start of the programme, were used as control. In the autologous pre-donation group, four received homologous transfusion and 11 escaped exposure to homologous blood or blood products. In comparison in control group 14 out of 15 received homologous transfusion. There was no significant difference between the two groups in terms of diagnosis, operating time, postoperative haemoglobin, body weight and age. Mean operative blood loss in autologous group was less (1190 mls) than in that of the control group (1529 mls). Of the four patients who received homologous transfusion, two were transfused outside the hospital protocol. Complications from pre-donation of blood occurred in three patients and were minor. They included minor bruising in two and difficult and painful venous cannulation in one. Conclusion: In our practice autologous pre-donation resulted in avoidance of homologous blood transfusion in three quarters of patients undergoing spinal deformity surgery. By adopting strategies such as acute normo-volaemic haemodilution, cell salvage and strictly adhering to protocols for prescribing transfusion, we believe that the need for homologous transfusion could be obviated except in extreme cases.
The purpose of this study was to audit screening and treatment programmes for Developmental Dysplasia of the Hip (DDH) over a 12-year period from 1989 to 2000 with respect to late presentation and treatment rate and duration. All babies born in Queen Mary Hospital are clinically screened for DDH by a consultant orthopaedic surgeon. Unstable hips are treated by Pavlik Harness and attend an ultrasound clinic run by an orthopaedic surgeon within 2 weeks. High-risk babies or those with suspected instability can also be referred for ultrasound. Serial ultrasound exams assisted with determining the duration of splintage. Radiographs are taken at 4 to 6 months. Late presenters were identified and analysed. Over the 12-year period 13 cases of late presenting DDH were identified (0.6 per 1000). Half of these had not been screened. None had ultrasound screening. Our treatment rate was approximately 4 per 1000 live births. Our screening programme can be improved by increased capture of patients for clinical screening. Ultrasound is a useful tool in managing neonatal hip instability allowing duration of splintage to be tailored to the individual and allows early detection of treatment failure.
The aim of the study was to review the role of Magnetic Resonance Imaging of the spine in discitis in the toddler age group (one to three years). Discitis presents differently in different age groups of children. It is most difficult to diagnose in the uncommunicative non-compliant toddler. The clinical features are often non-specific and laboratory and microbiological tests can be unhelpful. A highly sensitive test is required to aid in making the diagnosis. Although MR Imaging has been used in discitis for several years, we reviewed its actual effectiveness in this specific difficult age group. At a mean of 21 months at follow-up (range 10 to 40), MR imaging of the disc was variable, with partial recovery after 15 months and complete recovery after 34 months. Routine follow-up MR imaging was not recommended. We reviewed the role of Magnetic Resonance Imaging in eleven consecutive cases, both at presentation and at a follow-up clinic. MR imaging was diagnostic in all cases, reduced the diagnostic delay, and often avoided a disc biopsy. It demonstrated any paravertebral inflammatory collection, which helped in determining the duration of the oral therapy given after the initial intravenous antibiotics.
In the reconstruction of the exstrophy/epispadias complex pelvic osteotomy has a role in helping the urologist close the anterior defect thereby improving appearance and helping to achieve continence. In the neonate and infant, we have traditionally used an oblique osteotomy coupled with plastering of the legs until the osteotomy shows signs of healing. Plastering has significant disadvantages in respect of nursing care. We have therefore looked to external fixation in this age group. In the past year we have used the A.O. wrist fixator to stabilise the osteotomised pelvis of ten babies with bladder exstrophy ranging in age from neonates to two years. All have achieved soft tissue closure with improved appearance. However, because of the foreshortened anterior pelvis in the exstrophy patients, it is not possible to reconstruct to normality. The results to date are promising and the patients remain under follow up.
There is great confusion in the literature on mechano-transduction in osteoblasts. This is partly due to the use of hyper and hypophysiological systems for applying forces to cells. We only find evidence for the role of ion channels at hyper-physiological levels of strain. The cells are far more sensitive to tension than compression indicating that structures within the cell are decisive in determining response and that there is no tensegrity within the cell. Single cell mechanical measurements using an adapted atomic force microscope built in our lab, also does not show any evidence for a tensegrity structure. Analysis of the dimension of stretch and the amount of force needed to activate cells indicates that stretch activated ion channels are not involved as the force required is extremely high in relation to the activation energy of an ion channel. The force required to activate at the mechanosensing system is more in line with the forces generated inside a cell by the actin-myosin structure of several hundred thousand piconewtons. We find no evidence for any other pathway than a PLC-PKC-Calcium pathway involved in any of the signal transduction pathways, but other pathways are involved in hyperphysiological stretch. One of these induces ICAM-1 and thus can induce inflammatory pathways through cell-cell binding of macrophages and other cells. Due to the very high energies involved in activating the mechano-transduction pathways we do not see any graviception mechanism of single cells. Indeed many microgravitx flights of 25 seconds duration and a flight of 6 minutes did not show any effect in intracellular calcium. The cellular response to microgravity, if it is not an artefact, is not related to mechanosensing. This work was supported by the German Space Agency (DLR)
Using the trabecular bone bioreactor (ZETOS) developed in our laboratories we have investigated the formation of bone using the fluorescent bone seeking markers calcein and alizarin red. And the association of bone formation with the increase in stiffness with mechanical loading. 10 mm diameter bone cores 5 mm thick were obtained from the distal radius /ulna of cows obtained at the slaughter house. by precision cutting with diamond saws and keyhole cutters (our pattern) in sterile 7–10°C phosphate buffered saline (PBS) and cultured in a variation of DMEM containing fructose HI GEM.
We gratefully acknowledge support by the German Arthrose Foundation (DAH) and the AO in Davos, CH. DJ is a recipient of a Fork award from the AO
Intervertebral disc cells exsist in a precarious nutritional environment. Local concentrations depend on both nutritional supply and demand. Little is known about the metabolism of disc cells; existing data focuses on intact tissue, where the local metabolic environment is unknown. We have thus developed a closed chamber to study the metabolism of isolated cells under controlled conditions. Bovine disc cells were isolated from coccygeal discs and transferred to the sealed chamber, in which embedded electrodes measured pH, pO2 and glucose concentration, and a port allowed sampling and addition of metabolic reagents. Metabolic rates were assessed from concentration changes. Cell viability was assessed and intracellular ATP measured at completion of each experiment. Under standard conditions, metabolic rates were similar to those measured in tissue, with a glucose:lactic acid ratio of approximately one to two. We have also examined the effect of extracellular pH on nucleus pulposus cell metabolism. Between pH 7.4–6.8, metabolism is insensitive to extracellular pH, and lactic acid production agrees with the literature
These results show a fall in lactic acid production with extracellular acidification, which in vivo arises mainly from lactic acid produced by the cells. This may be protective. However the decrease in metabolism, and hence loss of ATP, may have a detrimental effect on the cells. There is thus a complex interplay between different components of the nutritional environment. Investigating these in combination should give valuable information about disc cell metabolism, as changes in cells metabolism can affect nutrient availability and hence cellular activity and viability.
Scoliosis is a disease characterised by vertebral rotation, lateral curvature and changes in sagittal profile. The role of mechanical forces in producing this deformity is not clear. It is thought that abnormal loading deforms the disc, which becomes permanently wedged. Modelling and in vitro studies suggest that such deformations should increase intradiscal pressure. Intradiscal pressure has been measured previously in a variety of clinical environments. The aim of this study is to measure pressure profiles across scoliotic discs to provide further information on the role of mechanical forces in scoliosis. Pressure readings were obtained in consented patients with ethical approval using a needle-mounted sterilised pressure transducer (Gaeltec, Dunvegan, Isle of Skye) calibrated as described previously. The transducer needle was introduced into the disc of an anaesthetised patient during routine anterior scoliosis surgery and pressure profiles measured. Signals were collected, amplified and analysed using Power-lab and a laptop computer. Pressure profiles across 10 human scoliotic discs from 3 patients have been measured to date. Pressures varied from 0.1 to 1.2 MPa. Annular pressures showed high pressure, non-isotropic regions on the concave but not convex side of these discs. Nuclear pressures recorded from the discs of these scoliotic patients were higher than those recorded previously in non-scoliotic recumbent individuals.
One of the mechanisms which controls bone growth, repair remodeling and absorption is mechanical loading. There exists no long-term in vitro model to study bone cells together with their matrix, nor a model that can apply quantitative mechanical forces of physiological amplitudes and frequencies. The analysis of the mechanical properties of bone (Young’s modulus and visco-elastic moduli) on small pieces of bone is also difficult with present devices. We have built a device that can maintain full viability and physiological response of bone for a period of several weeks and integrates all three functions. 10mm diameter bone cores 5 mm thick were obtained from the trabecular bone of the distal ulna of a 24 months old cow by precision cutting with diamond saws and keyhole cutters (our pattern) in sterile 7–10°C phosphate buffered saline (PBS) and cultured in a variation of DMEM containing fructose HI GEM.
We gratefully acknowledge support by the German Arthrose Foundation (DAH) and the AO in Davos, CH.