Radiostereometric analysis (RSA) has become the gold standard technique for measuring implant migration and wear following joint replacement due to its high measurement precision and accuracy. However, RSA is conventionally performed using two oblique radiographic views with the presence of a calibration cage. Thus, a second set of radiographs must be acquired for clinical interpretation, for example anterior-posterior and cross-table lateral views following total hip arthroplasty (THA). We propose a modification to the RSA setup for examining THA, in which RSA measurements are performed from anterior-posterior and lateral views, with the calibration cage images acquired separately from the patient images. The objective of the current study was to compare the accuracy and precision of the novel technique to the conventional technique using a phantom. X-ray cassette holders were developed to enable simultaneous acquisition of anterior-posterior and cross-table lateral radiographs with the patient in a supine position in the RSA suite. A Sawbones phantom with total hip implant components was attached to a micrometer-driven stage. The femoral component was translated known distances relative to the acetabular cup in all planes, mimicking head penetration due to wear. Double RSA examinations were acquired for each increment using the traditional and novel radiograph orientations. Translations were measured from the radiographic images using RSA software. For both techniques, accuracy was calculated by comparing the measured translations to the known translation from the micrometer, and reported as the 95% confidence interval. Precision was measured by comparing the measured translations between the double exams, and reported as the standard deviation. Accuracy was greater for the conventional technique in the inferior-superior axis (p = 0.03), greater for the novel technique in the anterior-posterior axis (p = 0.01), and equivalent in the medial-lateral axis (p = 0.06). Overall accuracy for both the conventional and novel techniques was identical at ±0.022 mm. Precision was equivalent between both techniques for the medial-lateral (p = 0.68), inferior-superior (p = 0.14), and anterior-posterior axes (p = 0.86). Overall precision for the conventional technique was ±0.127 mm and for the novel technique was ±0.095 mm. Utilising standard clinical radiograph view angles within an RSA exam had no detrimental effect on wear measurement accuracy or precision. This reduces the barriers to implementing RSA imaging in routine follow-up of arthroplasty patients, potentially greatly increasing the numbers of patients that can have quantitative data on implant performance. Future applications can involve applying more clinically relevant radiograph view angles to RSA exams of the knee and shoulder.
Identifying and scoring risk factors that predict early wound dehiscence and progression to metalwork infection. Results of wound healing, eradication of infection and union of with the use of vacuum dressing. Compare results of serial washouts against early vacuum dressing in this group of children with significant medical co-morbidities. A retrospective review of 300 patients with neuromuscular scoliosis who underwent posterior instrumented correction and fusion between 2008 and 2012 at two institutions. 10 patients had an early wound dehiscence which progressed to deep seated infection requiring wound washout(s) and subsequent vacuum dressing. Medical notes, clinical photographs and imaging were reviewed. Minimum follow up period was 14 months.Aims:
Method:
High velocity vertical aircraft ejection seat systems are credited with aircrew survival of 80-95% in modern times. Use of these systems is associated with exposure of the aircrew to vertical acceleration forces in the order of 15-25G. The rate of application of these forces may be up to 250G per sceond. Up to 85% of crew ejecting suffer skeletal injury and vertebral fracture is relatively common (20-30%) when diagnosed by plain radiograph. The incidence of subtle spinal injury may not be as apparent. A prospective study to evaluate spinal injury following high velocity aircraft ejection.Background
Aim
This study is to evaluate the effectiveness and outcome of our protocol: Russell traction followed by gentle manipulative reduction with a single screw fixation &
spica cast immobilization. Twenty-three patients with thirty hips of slipped capital femoral epiphysis were treated in our department, KK Women’s and Children’s Hospital, Singapore between 1997 and 2005. Except one patient lost of follow-up, twenty-four SCFEs with more than 2 years follow-up were reviewed. In this series, there were 13 boys &
5 girls, mean age 12 year old ranging from 10 to 14 years. Among them 7 were Chinese, 6 Malays &
5 Indians. There were 12 unilateral cases (8 on the left &
4 right, 67%) &
6 bilateral cases (33%), including 2 patients found contralateral SCFE subsequently 1 year postoperatively. Acute-on-chronic SCFE were 16 &
chronic SCFE 8. 16 were Grate I &
8 Grate II. Russell traction was on preoperatively with an average of 6 days. Gentle manipulative reduction under general anesthesia was performed in 20 SCFEs (12 GI &
8 GII) and 17 of them were successful. Fixation with a single screw was used for all cases except one hip with 2 screws. Average follow-up was 38.5 months. Good results achieved. All patient were symptom free with good function. No complications of AVN, chondrolysis, screw loosening and reslipping of the affective hips. Our protocol of management for SCFE has been largely successful in term of manipulative reduction and fixation. This is a safe, simple and effective management.
High velocity vertical aircraft ejection seat systems are credited with aircrew survival of 80–95% in modern times. Use of these systems is associated with exposure of the aircrew to vertical acceleeration forces in the order of 15–25G. The rate of application of these forces maybe upto 250G per sceond. Upto 85% of crew ejecting suffer skeletal injury and vertebral fracture is relatively common (20–30%) when diagnosed by plain radiograph. The incidence of subtle spinal injury may not be as apparent. A prospective case series, admitted to QMC Nottingham, from 1996 to 2006 was evaluated. During this interval 26 ejectees from 20 aircraft were admitted to the spinal studies unit for comprehensive examination, evaluation and management. The investigations included radiographs of the whole spine and magnetic resonance Imaging (incorporating T1, T2 weighted and STIR saggital sequences). All ejections occurred within the ejection envelope and occurred at an altitude under 2000 feet (mean 460 feet) and at an airspeed less than 500 knots (mean 275 knots). In this series 6 ejectees (24%) had clinical and radiographic evidence of vetebral compression fractures. These injuries were located in the thoracic and thoracolumbar spine. 4 cases required surgery ( indicated for angular kyphosis greater than 30 degrees, significant spinal canal compromise, greater than 50% or neurological injury. 1 patient had significant neurological compromise, following an AO A3.3 injury involving the L2 vertebra. 11 ejectees (45 %) had MRI evidence of a combined total of 22 occult thoracic and lumbar fractures. The majority of these ejectees with occult injury had multilevel injuries. This study confirms a high incidence if spinal fracture and particularly occult spinal injury. Evidently vertical emergency aircraft ejection imposes major insults on the spinal column. Once, appropriately prioritised, life preservation measures have been undertaken, an early MRI of the spne is mandatory as part of comprehensive patient evaluation. Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.
A consecutive series of 20 children with neuromuscu-lar scoliosis (age range 2–18 years) undergoing surgical correction were evaluated using 2 standard functional assessment tools, the Seated Postural Control Measure (SPCM) which assesses posture and function, and the Pediatric Evaluation of Disability Inventory (PEDI) which records functional ability in the domains of self-care, mobility and social function. The patients were evaluated pre-operatively and then at 2 weeks, 3 and 12 months post-operatively. Complete data is presented for all patients at 3 months and 13 of 20 patients at 1 year follow up, the remaining data is to be collected. The SPCM demonstrated an improvement in posture in 95% from pre-op to 2 weeks post-op, with 25% demonstrating some regression at 3 months. Most maintained or improved this at 1 year. The PEDI demonstrated a reduction in mobility at 3 months but at 1 year 60% returned to preop status.
Unpaired “t” test was used to compare the magnitude of correction in both groups. The mean follow up period was 6.7 months (range:3–18). The mean corrections of Cobb angle, AVR and AVT, in group I were 61.1% (range:48.5–83.9), 33.3% (range:8.6–100) and 62.9% (range:43.2–91.4), respectively. In Group 2 the corrections were: 57.4% (range:21.4–81.7), 57.2% (range:16.7–100) and 58.7% (range:34–80.9). There is no statistically significant difference between the correction of Cobb angle or AVT in both groups (P=0.479 and 0.443 respectively). However, the pedicle screws proved to be more effective at correcting the AVR (P= 0.017). No complications occurred and correction has been well maintained.
Anterior instrumentation for thoracic AIS has advanced to a point where it can be widely adopted, particularly if the patient expresses concerns regarding the rib hump or is hypokyphotic.
Many surgical approaches at decompression have been attempted for the thoracic outlet syndrome (TOS), but only the transaxillary and supraclavicular routes carry the best outcomes. More recently, a selective and tailored approach via the supraclavicular route has been favoured. We performed a retrospective review between 1978 and 1998, and report the outcome of the ‘’two surgeon approach’’ for TOS via the supraclavicular method. An orthopaedic and vascular surgeon jointly conducted 30 operations for disabling symptoms relating to TOS in 27 patients (21F, 6M), mean age of 29 yrs (range 18–63 yrs), having performed the preoperative assessment in conjunction with a neurologist. In all cases, it was essential that patient selection for surgery was determined on clinical grounds rather than the presence of a cervical rib. Anterior scalenectomy was performed via the supraclavicular route except in one case where the infraclavicular route was utilised. Additional surgical procedures were carried out according to the underlying abnormalities, i.e. excision of cervical rib or band or medial scalenectomy. The first rib was always spared. At mean follow-up of 37 mths (range 3-228 mths), 26/30 sides (87%) had excellent or good results. The results were fair or poor in three cases where scalenec-tomy alone was performed. There were no major complications and no patients required a re-operation. 24 patients (89%) returned to their previous lifestyle or occupation. Our results suggest that, with a multidisciplinary assessment and two-surgeon team, good to excellent surgical outcomes can be achieved via the supraclavicular route without resection of the first rib. Instead of the current practise of routine transaxillary first rib resection, we recommend decompression via this approach with further procedures tailored to the abnormality identified.