Polyethylene wear represents a significant risk factor for the long-term success of knee arthroplasty [1]. This work aimed to develop and in vivo validate an automated algorithm for accurate and precise AI based wear measurement in knee arthroplasty using clinical AP radiographs for scientifically meaningful multi-centre studies. Twenty postoperative radiographs (knee joint AP in standing position) after knee arthroplasty were analysed using the novel algorithm. A convolutional neural network-based segmentation is used to localize the implant components on the X-Ray, and a 2D-3D registration of the CAD implant models precisely calculates the three-dimensional position and orientation of the implants in the joint at the time of acquisition. From this, the minimal distance between the involved implant components is determined, and its postoperative change over time enables the determination of wear in the radiographs. The measured minimum inlay height of 335 unloaded inlays excluding the weight-induced deformation, served as ground truth for validation and was compared to the algorithmically calculated component distances from 20 radiographs. With an average weight of 94 kg in the studied TKA patient cohort, it was determined that an average inlay height of 6.160 mm is expected in the patient. Based on the radiographs, the algorithm calculated a minimum component distance of 6.158 mm (SD = 81 µm), which deviated by 2 µm in comparison to the expected inlay height. An automated method was presented that allows accurate and precise determination of the inlay height and subsequently the wear in knee arthroplasty based on a clinical radiograph and the CAD models. Precision and accuracy are comparable to the current gold standard RSA [2], but without relying on special radiographic setups. The developed method can therefore be used to objectively investigate novel implant materials with meaningful clinical cohorts, thus improving the quality of patient care.
The term flat foot is surrounded by confusion and there is little to help the clinician to identify cases which require treatment and to avoid treating many children unnecessarily. Research for 25 years has been aimed at elucidating this problem by identifying and evaluating a series of signs and tests. These tests allow the recognition of the abnormal foot as early as possible, when efficient treatment is likely to be most effective. The results indicate that evaluation of the flat foot should be based on a combination of signs, with most emphasis on the result of the great toe extension test.
High myelomeningocele lesions do not preclude an acceptable level of functional walking provided that an integrated programme of surgical treatment and bracing is adopted. Clinical analysis of 100 patients with myelomeningocele shows that the development of the "swivel walker" and "hip guidance orthosis" has been associated with an improved level of function. Over 30 per cent of patients with thoracic lesions and 68 per cent of those with lumbar lesions achieved independent walking. For this reason the criteria used at present by paediatricians to govern the selection of infants for non-active treatment may require reconsideration.
