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11. Personalised High Tibial Osteotomy Surgery Is Accurate: An Assessment Using 3D Distance Mapping.

Author

Varaschin, Andrea, Gill, Harinderjit Singh, Zaffagnini, Stefano, Leardini, Alberto, Ortolani, Maurizio, Norvillo, Fabio, MacLeod, Alisdair, Dal Fabbro, Giacomo, Cassiolas, Giorgio, Grassi, Alberto, and Belvedere, Claudio

Subjects
COMPUTER-aided design software, KNEE osteoarthritis, OPERATIVE surgery, FRACTURE fixation, TREATMENT effectiveness
Abstract

Early-stage knee osteoarthritis is often suitable for treatment with high tibial osteotomy (HTO). This is an effective joint-preserving treatment, resulting in good postoperative outcomes. To overcome the limitations of traditional HTO, the surgical technique and correction accuracy can be enhanced by personalised procedures using three-dimensional digital planning and metal additive manufacturing, The purpose of this clinical trial study was to evaluate the three-dimensional accuracy of a new personalised HTO procedure, using modern imaging techniques, 3D modelling, and distance map analysis (DMA). Twenty-five patients were treated with the personalised HTO procedure. Before surgery and after 6 months, they underwent clinical evaluation scoring, radiographic imaging, and computed-tomography scanning to generate morphological models. Specifically, preoperative tibia models were used to plan the tibia correction and the design and position of the fixation plate. Preoperative, planned, and postoperative models were imported in computer-aided and designing software (Geomagic ControlTM 2014, 3D Systems, Rock Hill, SC, USA) for DMA implementation to assess geometrical differences between model surfaces. A very good reproduction of the planned tibia morphology was achieved postoperatively (average differences between −0.9 mm and 1.4 mm). DMA values associated with fixation-plate deformation were less than 1 mm, similar to those for plate-to-tibia surface-contour matching. Overall, personalised digitally planned HTO utilising three-dimensional printed surgical guides and plates enables accurate planned correction and plate placement. [ABSTRACT FROM AUTHOR]

Published
2024
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25. The mechanics of heelstrike during level walking

Author

Gill, Harinderjit Singh

Subjects
571.4
Abstract

A review of the literature discussing the relationship between mechanical factors and osteoarthrosis (OA) is given. From this review, it is concluded that the impulsive loads experienced at heelstrike during normal level walking are associated with degeneration of the joints of the lower limb. The amount of loading experienced varies between individuals and it is proposed those with higher loading have a greater risk of developing OA. The apparatus and methods used to study the differences in heelstrike impulsive loading (HIL) in a subject population are described. The data from the gait studies is analysed using kinematic and kinetic models. The data confirms that the subject population consisted of two groups, one with a large HIL, the other with a small HIL. These differences are attributed to the kinematics of the swing leg, in particular the vertical velocity of the ankle at heelstrike. A two dimensional simulation model of the swing phase is developed. This model is used, together with an numerical technique, to change the swing phase pattern of a subject with a large HIL to that typical of a subject with a small HIL. The differences in joint moment between these two patterns is evaluated. A sagittal plane model of the patellofemoral joint is developed and described. This model is incorporated into an existing mathematical model of the lower limb. The lower limb model is used to evaluate the differences in muscular control effort required for the two swing phases described above. Differences are found in the phasing of the hip flexor muscles. It is concluded that changes in muscular phasic activity during early swing phase, combined with the dynamics of the swing leg, produce significant changes in the approach velocity of the ankle at heelstrike. Thus, the loading experienced at heelstrike is a function of the timing of muscle activity during swing phase and can be altered by training, so that preventative treatment of OA is possible.

Published
1996

37. Instrumental Gait Analysis and Tibial Plateau Modelling to Support Pre- and Post-Operative Evaluations in Personalized High Tibial Osteotomy.

Author

Belvedere, Claudio, Gill, Harinderjit Singh, Ortolani, Maurizio, Sileoni, Nicoletta, Zaffagnini, Stefano, Norvillo, Fabio, MacLeod, Alisdair, Dal Fabbro, Giacomo, Grassi, Alberto, and Leardini, Alberto

Subjects
GROUND reaction forces (Biomechanics), GAIT in humans, OSTEOTOMY, MOTION analysis, HOLMIUM, KNEE osteoarthritis
Abstract

Featured Application: The inclusion of gait analysis, suitably combined with anatomical modelling derived from patient-specific medical imaging, may lead in the near future to more robust post-operative evaluations of personalized HTO to support the efficacy of this surgical technique, as well as innovative and more biomechanically based pre-operative planning. High tibial osteotomy (HTO) is intended to treat medial knee osteoarthritis by realigning the joint such that the loading in the knee during functional activity shifts laterally. The aim of this study was to use a novel methodology combining motion analysis and 3D modelling to assess the efficacy of this surgery in changing the loading location in the knee in a cohort of 25 patients treated with personalized HTO. Pre-operatively and at 6 months post-surgery, weight-bearing CT and gait analysis during level walking were performed on all patients, as well as clinical evaluations using KOOS and VAS scores. CT scans were used to generate a knee bone model and a virtual tibial plateau plane; the intersection pattern between this plane and the ground reaction force (GRF) vector was calculated in the pre- and post-operative gait analyses. Clinical scores improved significantly (p < 0.001) after surgery (pre-/post-operative KOOS and VAS: 56.2 ± 14.0/82.0 ± 8.3 and 6.3 ± 1.7/1.5 ± 1.7). Post-operative GRF-to-tibial plateau intersection patterns were significantly (p < 0.001) more lateral (31.9 ± 19.8% of tibial plateau width) than the pre-operative patterns. Personalized HTO successfully and consistently lateralizes the GRF at the knee, in association with significant improvements in function and pain. The novel combination of 3D bone modelling and motion analysis also has the potential to further aid HTO surgical planning. [ABSTRACT FROM AUTHOR]

Published
2023
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44. 3D MEDICAL IMAGING ANALYSIS, PATIENT-SPECIFIC INSTRUMENTATION AND INDIVIDUALIZED IMPLANT DESIGN, WITH ADDITIVE MANUFACTURING CREATES A NEW PERSONALIZED HIGH TIBIAL OSTEOTOMY TREATMENT OPTION.

Author

BELVEDERE, CLAUDIO, MACLEOD, ALISDAIR, LEARDINI, ALBERTO, GRASSI, ALBERTO, FABBRO, GIACOMO DAL, ZAFFAGNINI, STEFANO, and GILL, HARINDERJIT SINGH

Subjects
THREE-dimensional imaging, SCREWS, SELECTIVE laser sintering, IMAGE analysis, DIAGNOSTIC imaging, OSTEOTOMY, KNEE, OPERATIVE surgery
Abstract

High Tibial Osteotomy is frequently performed to correct varus knees misalignment and thus to prevent end-stage osteoarthritis. Traditional systems lack pre-surgical planning and custom-fit fixation plates. A new 3D printed system has been developed for a personalized surgical procedure. This starts with careful correction planning based on a standard preoperative long leg radiograph and a 3D scan of the knee by Cone-Beam CT, both in weight-bearing. From the latter, a 3D model of the proximal tibia is reconstructed, on which the surgery is planned. This allows the design of the surgical guide and fixation plate to match the tibial surface topology and 3D printed in medical grade titanium alloy using selective-laser-sintering. During surgery, the guided osteotomy and controlled opening mechanism ensure an accurate correction; this is stabilized with the custom-fit plate secured to the proximal tibia using locking screws of appropriate length. After a brief learning curve, the mean discrepancy between the plan and the achieved alignment was 1. 2 ∘ ± 1. 4 ∘ . The surgical time was reduced by an average of approximately 30%. From medical imaging of the patient to product delivery to the hospital, the overall timeframe was about 15 days. [ABSTRACT FROM AUTHOR]

Published
2023
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