Abstract

Abstract

Abstract

Abstract

Purpose

Femoroacetabular impingement syndrome (FAI) is a common cause of hip and groin pain in young adults. Physiotherapy and surgery have both been used to treat FAI syndrome, but there is no robust evidence of comparative effectiveness. UK FASHIoN compared the clinical and cost-effectiveness of arthroscopic hip surgery (HA) versus best conservative care in patients with FAI syndrome.

Background

Traditionally, a Surgical Tourniquet (ST) is used during Total Knee Replacement Surgery (TKRS) to prevent blood flow to the leg and improve the surgical field of view. The use of a ST is known to increase the risk of venous thromboembolism. Echogenic material, suggestive of emboli has been observed in the brain following ST deflation in TKRS despite the absence of a patent foramen ovale, likely through pulmonary shunts. The aim of this study was to assess whether cerebral emboli result from tourniquet use in TKRS and the sequelae of any emboli.

The Ilizarov frame is a circular external fixator, invented by Professor Ilizarov in Siberia during the 1950’s. It uses the principle of distraction osteogenesis to form new bone in a variety of clinical situations where bone lengthening or realignment is needed. The Ilizarov frame began to be used in western medicine during the 1980’s and by 1993 over 6000 cases had been performed in Europe.

Plain x-ray is one of the methods used to monitor the progress of patients fitted with an ilizarov frame.

The aim of this study is establish a pattern of healing over time in patients with the Ilizarov frame using plain x-ray films. This will improve understanding of the procedure, aid clinicians in deciding when frame removal is appropriate and provide a method of early detection should healing not be progressing appropriately.

This is a retrospective study looking at a series of 58 digitised anterior-posterior x-ray films of the tibia and fibula, taken at set time points post-operatively, from 17 patients fitted with an ilizarov frame (19 separate legs with ilizarov frames in total). Image J, an image analysis system, was used to measure pixel density from vertical slices down the centre of each fracture gap and at set intervals horizontally across the fracture gap. A mean pixel density value for each fracture gap was also calculated. The x-rays were standardised using a standard step wedge.

Promising preliminary results show pixel density to be greater towards the medial aspect of the tibia, but this difference in pixel value decreases with time. This suggests that calcification of the new bone occurs medially to laterally across the tibia. Full results will be available in April and aim to build a picture of the fracture gap at set time points post-operatively, showing a pattern of calcification in patients with the Ilizarov frame that will become a useful clinical tool for deciding time of frame removal as well as affording early knowledge of problems with the healing process.

Measurement of the rate of fracture healing is a major problem in fracture research. Bone mineral density (BMD) of fracture callus has been used as a measure of healing in diaphyseal fractures. However, metaphyseal fractures (especially in the elderly) are now the commonest type of fracture and are a significant public health problem. This study investigated whether measurement of BMD at the fracture site in the distal radius can be used as a measure of fracture healing.

We recruited 28 patients who had sustained a dorsally displaced distal radial fracture which was deemed to require treatment by intrafocal wire fixation. All patients had acceptable correction of dorsal and radial angle at final x ray (3 months). Wrist function was measured using the Patient Rated Wrist Evaluation (PRWE – a validated outcome measure for use after distal radial fractures), grip strength,and range of motion. All measurements were made at 6, 12 and 26 weeks. BMD was measured at the fracture site (examining the BMD of the medullary bone at the fracture site after removal of wires), in the opposite wrist and the lumbar spine using QCT at 6 weeks after fracture.

There was no correlation between fracture site BMD and BMD at the other wrist or the lumbar spine (r < 0.3). The BMD at the fracture site was higher than the BMD at the other wrist (mean 168 vs 70 HU; p< 0.001 paired T test). There was no relationship between fracture site BMD or the ratio of BMDs fracture site / normal wrist, and any of the functional assessments (proportion grip strength recovered, range of motion or PRWE (r < 0.3)).

15 of these patients underwent a second QCT at 12 weeks after fracture. There was no significant change in fracture site BMD between the first and second scan.

These data indicate that fracture site BMD is unlikely to be a useful method of measuring metaphyseal bone healing. The increase in BMD at the fracture site was unexpected; possible explanations include impaction of bone or high BMD in woven bone (the relationship of which to bone stiffness is uncertain).

The Ilizarov technique of distraction osteogenesis is becoming a more common way of treating complicated fractures. It has been shown that shear IFMs will delay bone healing whilst axial IFMs are beneficial to the bone healing. Therefore to measure IFMs in conditions of mobility will provide critical information for research and clinic diagnosis. Such data are not provided by static measurements. Traditionally the IFMs were measured by implanting transducers to the bone or using radiological methods. However, these methods are not suitable for either clinic utilization or measurement of IFMS when patients are doing movements which simulate their daily activities. We have designed a dynamic IFMs measuring device.

It includes a displacement transducer array, which is connected to the Ilizarov wires. This transducer array consists of 6 parallel linear displacement transducers, each of which is attached to the fixing wires of the fix-ator. This arrangement of transducers can fit into the configuration of Stewart Platform. The Reverse Stewart Platform algorithm was employed to calculate IFMs. Without measuring the bone fracture segments directly, the two segments were fitted into two planes virtually. By studying the relative movements of the two virtual planes, the algorithm transfers the relative movement to relative axial & shear translation, and relative bending & torsion rotation, between the two fracture segments. Wireless interface was used to transfer the displacement readings from the transducer array to the computer. This setup allows patient perform activities which represent their routine activities.

In laboratory studies, we found the error of this system to be related to the IFMs. For small movements around 100 micron, the absolute error was 50 micron, whereas for larger movements around 1 mm, the error was within 0.22mm.

This real time monitoring method will allow kinematical and kinetic studies on fracture patients treated with Ilizarov frame. Measurements obtained using this novel device will reflect the natural pattern of IFMs during the patients’ daily life. Since use of the device requires no additional pin, wire or operative procedure, it will be clinically applicable. The accurate real-time IFMs measurements will help elucidate the complex interplay between movement and bone formation.

Older fracture patients frequently ask whether their osteoporosis will affect fracture healing. There is only limited previous data about this. We investigated recovery after distal radial fracture, and compared it with BMD of the other distal radius and the lumbar spine (measured using quantitative CT).

All 28 patients had sustained a dorsally displaced distal radial fracture which was deemed to require treatment by intrafocal wire fixation. All patients had acceptable correction of dorsal and radial angle at final x ray (3 months). Wrist function was measured using the Patient Rated Wrist Evaluation (PRWE – a validated outcome measure for use after distal radial fractures), grip strength,and range of motion. All measurements were made at 6, 12 and 26 weeks. BMD was measured in the opposite wrist and the lumbar spine using QCT at 6 weeks after fracture.

There was no correlation between recovery of grip strength (% of contralateral grip strength) at 6,12,or 26 weeks with BMD at either site. Similarly, there was no correlation between BMD and either absolute PRWE scores at any time point or improvement in PRWE between time points. The strongest predictor of recovery of grip appeared to be the proportion of grip recovered at 6 weeks (correlation between% grip recovered at 6 weeks and 3 months r = 0.85; at 6 weeks and 6 months r= 0.56; both p < 0.001). This was not affected by age or variations in measured final dorsal or radial angles or length within this group. It was not affected by degree of preoperative fracture displacement.

These data suggest that recovery of function after distal radial fractures is not influenced by osteoporosis. The data about the importance of initial recovery of grip suggest that factors other than bone position and bone healing may affect rate of functional recovery after distal radial fracture.

While the early period of distraction osteogenesis has been extensively investigated, there are very few data describing the long-term morphology of the regenerate. We performed magnetic resonance scans in ten adults (men age 35+− 11 yr), seven of whom had bone transport for an iatrogenic osseous defect while further three had tibial lengthening for limb length discrepancy. Follow-up ranged between 14 and 43 months (mean : 28 + − 10 months) following the removal of the external fixator. The perimeter, cross- sectional area, volume and the mean signal intensity was calculated from the obtained T1 weighted axial images. Values were compared with the contralateral tibia that acted as control. All cases that had bone transport increased the volume of the tibia from 15.3% up to 50.8%. The regenerated segment was noted to have expanded significantly (p< 0.0001) in all cases. Mean signal intensity in the regenerate decreased in seven cases significantly (p< 0.0001) suggesting increase content of unhydrated tissue such as bone and collagen. The cross-sectional surface of the transported segment was increased in all cases (p< 0.008). Finally in cases that underwent bone transport, the docking site was noted to be obstructed by unhydrated tissue. Contrary to previous claims, the post-distraction osteogenesis tibia is far from normal, consisting of areas with potentially different biomechanical properties. Recognition of these changes is essential not only for appropriate pre-operative counselling but also for considering treatment modalities in case of a fracture.

Introduction: While the early period of distraction osteogenesis has been extensively investigated, there are no data describing the long-term morphology of the regenerate. Patients and Methods: We performed MRI scans to ten adults, seven of which had bone transport for an osseous defect while further three had lengthening for limb length discrepancy. Follow up ranged between 14 and 43 months (mean: 29 months) following the removal of the external fixator. The perimeter, cross sectional area, volume and the mean signal intensity was calculated from the obtained T1 weighted axial images. Values were compared with the contralateral tibia that acted as control. Results: All cases that had bone transport increased the volume of the tibia from 15.3% up to 50.8%. The regenerated segment was noted to have expanded significantly (p< 0.0001) in all cases. Mean signal intensity in the regenerate decreased in seven cases significantly (p< 0.0001) suggesting increase content of unhydrated tissue such as bone and collagen. The cross sectional surface of the transported segment was increased in all cases (p< 0.008), which associated increase in the signal intensity (p< 0.003). Finally in cases that underwent bone transport, the docking site was noted to be obstructed by unhydrated tissue. Conclusions: Contrary to previous claims, the post-distraction osteogenesis tibia is far from normal, consisting of areas with potentially different biomechanical properties. Recognition of these changes is essential not only for appropriate preoperative counselling but also for considering treatment modalities in case of a fracture.

Objective: Movement in an artificial disc would be assumed to be a necessary function of the disc. The purpose of this study was to establish whether, if any, relationship existed between movement in the artificial disc and outcome.

Subjects: 25 patients who had received an artificial disc prosthesis were assessed using radiological methods. Despite many vagaries in the measurement of X-rays, fluoroscopy was used to assess gross movement and end of flexion/extension views used to measure degrees of motion.

Outcome measures: Oswestry disability score.

Results: A very clear relationship has been established between motion in the artificial disc and outcome.

Conclusions: It is likely that spinal fusion will ultimately give way to disc replacement. Although spinal fusion has been shown in the Swedish spine series to produce good outcomes for significant numbers of patients, it remains to be seen whether the retention of motion will enhance outcome in low back pain patients. This series suggests that the retention of motion is an important component in the outcome of surgery in back pain sufferers.