Browsing by Author "Folgado, J"
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- Influence of age-related bone density changes on primary stability in stemless shoulder arthroplasty: A multi-implant finite element studyPublication . Monteiro, HL; Antunes, M; Sarmento, M; Quental, C; Folgado, JBackground: Stemless implants were introduced to prevent some of the stem-related complications associated with the total shoulder arthroplasty. Although general requirements for receiving these implants include good bone quality conditions, little knowledge exists about how bone quality affects implant performance. The goal of this study was to evaluate the influence of age-induced changes in bone density, as a metric of bone quality, in the primary stability of five anatomic stemless shoulder implants using 3D finite element (FE) models. Methods: The implant designs considered were based on the Global Icon, Sidus, Simpliciti, SMR, and Inhance stemless implants. Shoulder arthroplasties were virtually simulated in Solidworks. The density distributions of 20 subjects from two age groups, 20 to 40 and 60 to 80 years old, were retrieved from medical image data and integrated into three-dimensional FE models of a single humerus geometry, developed in Abaqus, to avoid confounding factors associated with geometric characteristics. For the designs which do not have a solid collar covering the entire bone surface, i.e., the Sidus, Simpliciti, SMR, and Inhance implants, contact and non-contact conditions between the humeral head component and bone were considered. Primary stability was evaluated through the assessment of micromotions at the bone-implant interface considering eight load cases related to rehabilitation activities and demanding tasks. Three research variables, considering 20 μm, 50 μm, and 150 μm as thresholds for osseointegration, were used for a statistical analysis of the results. Results: The decreased bone density registered for the 60-80 age group led to larger micromotions at the bone-implant interface when compared to the 20-40 age group. The Global Icon-based and Inhance-based designs were the least sensitive to bone density, whereas the Sidus-based design was the most sensitive to bone density. The establishment of contact between the humeral head component and bone for the implants that do not have a solid collar led to decreased micromotions. Discussion: Although the age-induced decline in bone density led to increased micromotions in the FE models, some stemless shoulder implants presented good overall performance regardless of the osseointegration threshold considered, suggesting that age alone may not be a contraindication to anatomic total shoulder arthroplasty. If only primary stability is considered, the results suggested superior performance for the Global Icon-based and Inhance-based designs. Moreover, the humeral head component should contact the resected bone surface when feasible. Further investigation is necessary to combine these results with the long-term performance of the implants and allow more precise recommendations. Keywords: Shoulder arthroplasty; bone density; finite element method; micromotions; primary stability; stemless shoulder implants.
- Influence of the rotator cuff tear pattern in shoulder stability after arthroscopic superior capsule reconstruction: a computational analysisPublication . Antunes, M; Quental, C; Folgado, J; Ângelo, AC; de Campos Azevedo, CObjectives: To assess the ability of the arthroscopic superior capsule reconstruction (SCR) in restoring glenohumeral stability in the presence of different preoperative patterns of irreparable rotator cuff tears (RCTs). Methods: A computational musculoskeletal (MSK) model of the upper limb was used to simulate isolated SCR and to estimate the stability of the shoulder. Four patterns of preoperative irreparable RCTs were modeled: Supraspinatus (SSP); SSP + Subscapularis (SSC); SSP + Infraspinatus (ISP); and SSP + SSC + ISP. The muscles involved in the irreparable RCT were removed from the MSK model to simulate an irreparable full-thickness tear. In the MSK model, the muscle and joint forces were estimated for a set of upper limb positions, from four types of motions (abduction in the frontal plane, forward flexion in the sagittal plane, reaching behind the back, and combing the hair) collected in a biomechanics laboratory, through inverse dynamic analysis. The stability of the shoulder was estimated based on the tangential and compressive components of the glenohumeral joint reaction force. The comparison of pre- and post-operative conditions, for the four patterns of irreparable RCTs, with the healthy condition, was performed using ANOVA and Tukey's tests (statistical level of p < 0.05). Results: In the setting of an isolated irreparable SSP tear, SCR statistically significantly improved stability compared with the preoperative condition (p < 0.001). For the irreparable SSP + SSC pattern, a statistically significant loss in stability was observed (p < 0.001) when SCR was applied. For the irreparable SSP + ISP and SSP + SSC + ISP patterns, the postoperative condition increased shoulder stability, compared to the preoperative condition; however, the improvement was not statistically significantly different. Conclusion: Isolated SCR for irreparable RCTs extending beyond the SSP does not statistically significantly improve the stability of the glenohumeral joint
- Why are tapes better than wires in knotless rotator cuff repairs? An evaluation of force, pressure and contact area in a tendon bone unit mechanical modelPublication . Maia Dias, C; Gonçalves, SB; Completo, A; Tognini, M; da Silva, MR; Mineiro, J; Curate, F; Ferreira, F; Folgado, JKnotless repairs have demonstrated encouraging performance regarding retear rate reduction, but literature aiming at identifying the specific variables responsible for these results is scarce and conflictive. The purpose of this paper was to evaluate the effect of the material (tape or wire suture) and medial tendon passage (single or double passage) on the contact force, pressure and area at the tendon bone interface in order to identify the key factors responsible for this repairs´ success.