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JOINTANALYSIS.COM an orthopaedic imaging company


jointanalysis.com We generate reports, with accurate and precise 3D measurements of human joints.


JOINT ANALYSIS We are an orthopaedic imaging company specialising in the 3D analysis of human joints and joints replacements. Joint Analysis has developed a range of services using imaging technology that accurately describe the orientation, position and size of symptomatic hip or knee joints in comparison to the normal. Our aim is to help surgeons to achieve optimal function of joint replacements for their patients through pre-operative planning. Our service can also be used for diagnosis if patients continue to experience problems after their artificial joint replacement surgery.


CONTENTS Why use 3D jointanalysis for the hip? .................................................................................... 4 3D Hip report example.............................................................................................................5 Total Hip Replacement Visualisation.......................................................................................6 Planning Hip Resurfacing..........................................................................................................7 3D planning for the optimal hip replacement......................................................................8-10 Femoral offset ................................................................................................................. 8 Femoral neck angle ..........................................................................................................9 Acetabular version ..........................................................................................................10 Visualising post-operative hip replacement pathology .........................................................11 Why use 3D analysis for the knee? ...................................................................................12-19 3D Planning for unicondylar knee arthroplasty..........................................................12-13 Post-operative reports for total knee arthroplasty....................................................14-15 ACL analysis......................................................................................................................16 Femoral condyle fracture visualisation and analysis......................................................17 Patello-femoral arthroplasty analysis..............................................................................18 Tibial plateau malunion analysis prior to lateral UKA surgery.........................................19


We know that optimal reconstruction of hip anatomy maximises the durability of a hip replacement. Planning is thought to increase the chance of an optimal reconstruction. However plain radiographic measurements of the hip are notoriously less accurate and less precise (repeatable) than CT based measurement.


3D CT hip report example Low radiation dose CT (equivalent to 2 pelvic plain radiographs) generates data to be used by our custom made and validated 3D software.


The ability to visualise pre-operatively the anatomy of the hip in three dimensions allows optimum choice of stem, head size, neck length and cup size for a total hip replacement to be made pre-operatively. Pre-operative visualisation provides an assurance that chosen implants will fit the patient’s anatomy.


Planning Hip Resurfacing It is important when performing hip resurfacing surgery that the angulation of the cup is correct in order to prevent dislocation and metal ion production and to provide a good range of motion. Angulation of the femoral head stem and sizing of the head are also important to ensure loads are correctly carried down the femoral neck. By visualising the patient’s anatomy in three-dimensions and overlaying implants, implants can be sized pre-operatively and correct orientations can be planned.


Good hip replacement function partly depends on optimal horizontal femoral offset. However, measurements from plain radiograph are less valid than CT, partly because plain radiographic measurement of HFO depends on the femoral rotation.


Hip replacement systems allow the head centre to be placed in many positions. However, radiographic analysis can be misleading. 3D jointanalysis will provide both the femoral offset and angle.


Planning the optimal acetabular version. Acetabular version varies between: 1 and 33 degrees for the native hip; and minus 47 and 68 degrees for the implanted hip replacement. 3D jointanalysis measures the version using points in the acetabular rim. Validation has shown good agreement with just labelling points in the psoas valley and 180 degree posteriorly. 3D jointanalysis will then tell a surgeon what version he will achieve if he using the psaos valley and ischial rim landmarks for intra-operative cup alignment.


In this case cysts were evident around the acetabular cups of a bilateral total hip replacement. The analysis provided a visualisation of these anterior supra-acetabular cysts and measurements of their dimensions.


By showing the surgeon the size and shape of the knee in three dimensions, a plan can be made with confidence that the right component size will be selected.


A three dimensional visualisation of the bones with implants overlaid allows the optimal implant size and position to be determined preoperatively. Visualisations on solid models, transparent models and CT slices allow the implant to be seen in relation to the overall anatomy and underlying structures.


Post-operatively, implants can be visualised and measurements made in the context of the patient’s anatomy. A post-operative analysis can indicate why an implant may not have been successful, and provide information necessary for revision surgery.


In this case the bone quality under the implant was suspected of being poor resulting in a loosening of the implant, and revision surgery was required. A report provided a measurement of the extent of the poor quality bone, and of the original implant, allowing an appropriately sized revision component to be chosen.


These images show the orientation of an ACL screw (in green) in the femur and the trajectory of the optimal revision tunnel (in purple) confirming that it can avoid the original tunnel altogether.


These images of a malunited femoral condylar fracture confirmed that the rest of the joint was relatively undamaged.


These images helped plan a patello-femoral arthroplasty. By confirming the size and orientation of the trochlea and patella.


The image on the left shows a tibial plateau malunion, while the image on the right shows the normal unaffected side. The measurements of the normal side allowed the surgeon to plan the reconstruction with a lateral unicompartmental knee arthroplasty.


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Mr Alister Hart MA FRCSG (Orth) Senior Lecturer & Honorary Consultant Orthopaedic Surgeon ! Professor Justin Cobb MCh(Oxon) FRCS Professor of Orthopaedic Surgery Imperial College The Joint Analysis Team Dept of Biosurgery and Surgical Technology Imperial College London Charing Cross Campus Room 7L19 Lab Block St Dunstan’s Road London W6 8RP Tel: 020 3313 4421 Fax: 020 3313 4427 Email: info@jointanalysis.com


www.jointanalysis.com

jointanalysis.com  

an orthopaedic imaging company specialising in the 3D analysis of human joints and joint replacements.