Marco Mannisimedere srl · R&D
Skills and Expertise
Research Items (11)
- Dec 2018
Background: Lateral wedge insoles (LWIs) are non-surgical interventions used in medial knee osteoarthritis (KOA) aiming at restoring correct joint biomechanics. However, the mechanical efficacy of LWIs, based on modulation of the external knee adduction moment, is partially proved and high variability in response to these devices was observed. Research question: The principal aim of the study was to employ subject-specific musculoskeletal models to investigate the immediate effect of LWIs on the medial compressive force (MCF) in a population with medial KOA and varus alignment. Methods: Fifteen adults (8 healthy controls age 56±3.4, BMI 25.2±2.2, hip-knee-ankle angle −1.3±2.3; and 7 KOA participants age 62±6.6, BMI 31.7±3.9, hip-knee-ankle angle 6.3±2) were recruited. Subject-specific LWIs were designed in CAD based on shape capture of the foot and manufactured via 3D printing. The required degree of heel post was added to the orthotic shell to create insoles with 0° 5° and 10° of lateral wedge. Gait data were collected for each condition and a musculoskeletal model implemented in the Anybody Modeling System estimated the CFs normalised per bodyweight. The effect of the LWIs with respect to the baseline on the peak and the impulse of the MCF were tested with a Wilcoxon non-parametric test for paired samples. Results: For the KOA group, LWIs did not reduce significantly the impulse and the peak of the MCF. No dose-response trend according to the degree of wedging was observed. A high inter-subject variability was found: the impulse of the MCF varied between −12%, +10%, the peak between −5%, +7%. Moreover, LWIs had no consistent effect on shifting the load from the medial to the lateral compartment. Significance: Subject-specific response to LWIs in a cohort of medial KOA patients was observed. Further studies are necessary to maximise the mechanical effect of LWIs on restoring normal knee joint mechanics.
Introduction Lateral wedged foot orthoses (LWFO) aim to re-establish correct biomechanics in patients with medial knee osteoarthritis (MKOA). However, evidence supporting the effectiveness of LWFO is contrasting and may depend on orthoses design . Therefore, the purpose of this study was to estimate the effect of two different LWFO designs on the medial knee contact force (MKCF) in participants with MKOA. Methods A 2x2 crossover trial was designed to compare the effect of two orthoses on the MKCF. The Lateral Wedge Technology Insole (SalfordInsole™, UK) was selected as a non-customised (NC) device while a 3D-printing approach was developed to create a modular insole (MOD) customised to participants’ foot geometry. Nineteen volunteers with MKOA (age 54.96 ± 5.78 years, BMI 30.9 ± 5.1 Kg·m-2) participated in this IRB approved study and provided informed consent. Each participant attended 4 sessions: (1) First Shod Baseline, (2) First Orthotic, (3) Second Shod Baseline, (4) Second Orthotic. Marker-based three-dimensional kinematic data and ground reaction forces were recorded during each session. Participants were asked to use each of the two LWFO for a period of 12 days prior the test. A 1 week washout period was given between assessment (2) and (3). The LWFO order was randomly assigned. An anatomically scaled musculoskeletal model was implemented using the Anybody Modeling System v.6.0.5 (AnyBody, Denmark) to estimate the knee MCF . The impulse of the MKCF, corrected per bodyweight, was chosen to estimate the LWFO effect. Non-parametric Wilcoxon Signed Rank Tests were performed to determine the effect of the NC and MOD LWFO with respect to the shod baselines. Results Results indicated that the median (Mdn) of the impulse of the MKCF for the NC, Mdn=0.91, was not significantly lower than the median at the corresponding baseline, Mdn=0.95, Z=141, p<0.059. The median of the impulse of the MKCF for the MOD, Mdn=0.96, was significantly higher than the median at the corresponding baseline, Mdn=0.93, Z=149, p<0.03. No significant difference was found between the two baseline assessment, Z=120, p=<0.314. No differences were found in the walking speed for both the NC and MOD with respect to the baselines. Discussion Results showed a limited effect of the two LWFO on the MKCF and a highly variable response. The MKCF increased significantly with the MOD while decreased, although not significantly, with the NC. To improve the effect of LWFO on the MCF, an innovative approach investigating advanced design characteristics and different materials in the production of the LWFOs may merit further attention.
Knee osteoarthritis (KOA) is most common in the medial tibial compartment. We present a novel method to study the effect of gait modifications and lateral wedge insoles (LWIs) on the stresses in the medial tibial cartilage by combining musculoskeletal (MS) modelling with finite element (FE) analysis. Subject's gait was recorded in a gait laboratory, walking normally, with 5° and 10° LWIs, toes inward ('Toe in'), and toes outward ('Toe out wide'). A full lower extremity MRI and a detailed knee MRI were taken. Bones and most soft tissues were segmented from images, and the generic bone architecture of the MS model was morphed into the segmented bones. The output forces from the MS model were then used as an input in the FE model of the subject's knee. During stance, LWIs failed to reduce medial peak pressures apart from Insole 10° during the second peak. Toe in reduced peak pressures by -11% during the first peak but increased them by 12% during the second. Toe out wide reduced peak pressures by -15% during the first and increased them by 7% during the second. The results show that the work flow can assess the effect of interventions on an individual level. In the future, this method can be applied to patients with KOA.
Medial compartment knee osteoarthritis (KOA) is a common musculoskeletal disease characterised by pain and functional limitations. Modifications in the foot progression angle and step width have been used as a strategy to reduce the external knee load. In this study, a subject-specific musculoskeletal model was implemented to analyse the mechanical efficacy of gait alterations during stairs ascent/descent on knee medial compressive force in a cohort characterised by clinical diagnosis of medial KOA and varus malalignment. Our findings showed a high variability in response to different gait modifications and did not suggest an overall mechanical efficacy.
- Jul 2014
- 7th World Congress of Biomechanics
Introduction The increasing number of uncemented total hip arthroplasty (THA) leads to a significant number of revisions, mainly due to aseptic loosening, despite their high survival rate (Italy [RIPO], UK, Australia hip registers). FE models proved effective in pre-clinical validation of implant designs but FE-based prediction of in vivo THA performance was reported only for cemented implants . Aim of the present study is to verify whether subject-specific FE models from pre-operative CT, featuring personalized loading conditions can identify failures from controls (successful at 10 years) in uncemented THA. Methods At Istituto Ortopedico Rizzoli, primary uncemented THAs with pre-operative CT planning were identified. We analysed only modular-neck implants (APTA, Adler-Ortho; ANCa-FIT, Wright-Cremascoli-Ortho) to increase model comparability. Three failures (one aseptic loosening, two peri-prosthetic fractures, one of which likely induced by previous aseptic loosening) were detected, 15 controls (successful at 10 years) were randomly selected. Stems were positioned from planning and adjusted by a post-operative radiograph. 10-node tetrahedral meshes of implanted bones were generated. Stems were assigned titanium alloy properties, bones inhomogeneous properties from CT. Personalised estimates of hip reaction and muscle forces were obtained at peak loading instants of level walking and stair climbing from a database of muscoloskeletal loads of THA patients. Large-sliding bone-implant contact was implemented (friction=0.3), verified by penetrations <1μm. Bone-implant micromotion over the whole contact area was used to identify stem loosening, peak bone strain and contact pressure to identify peri-prosthetic fracture. Results The two aseptic loosening-related failures differed significantly from controls in the overall bone-implant micromotions for both motor tasks. Failures and controls were clearly identified by normalized plots of cumulative micromotions, which diverged around the 75th percentile, with a 10μm gap at 85th percentile (controls 35μm). In the peri-prosthetic fracture case, peaks of minimum principal strain and contact pressure coexisted at the implant tip, where fracture occurred, but discrimination from controls could not be clearly achieved. Discussion FE-based bone-implant micromotion consistently identified two aseptic loosening cases among 15 controls. Despite the small sample size, our preliminary study corroborates FE models ability to predict in vivo implant-outcome and subject-specific biomechanical failure risk.