Hill-Sachs lesion measurement with tridimensional models in anterior shoulder instability / Avaliação da mensuração da lesão de Hill-Sachs em modelos tridimensionais na luxação anterior de ombro

ABSTRACT Objective To evaluate the reproducibility and repeatability of Hill-Sachs lesion measurement from computed tomography images, with computer software and tridimensional prototype. Methods Three-dimensional models were made from computed tomography images from 14 patients with anterior shoulder instability, using InVesalius 3.0® software. Hill-Sachs lesions were measured with Rhinocerus 5.0® software with pre-determined position. Mid-lateral distance, perpendicular to humeral shaft, cranial-caudal distance, parallel to humeral shaft, and the longitudinal distance of the lesion were measured. Using the Printer-ZP 310 three-dimensional printer, plaster models were made. To measure the Hill-Sachs lesion, a calibrated universal digital caliper was used in the same way as the software. Results There was intra-observer and inter-observer variability for measurement of the same model. Observers did not perform the measurements in a similar way, showing difficulty to use the method (p < 0.05). Using the software to measure the mid-lateral distance, as well as in the measurement with the caliper, the model type influenced the measurements for each of the observers, rendering the method invalid (p < 0.05). Conclusion There was no reproducibility and repeatability for Hill-Sachs lesion measurement between plaster models and software models.

RESUMO Objetivo Verificar se há reprodutibilidade e repetibilidade das mensurações diretas da lesão de Hill-Sachs (HS), a partir de imagens de reconstrução tomográficas, com o uso do programa de computador e em modelos obtidos por impressora tridimensional. Métodos Usaram-se imagens tomográficas de 14 pacientes com luxação recidivante do ombro feitas pelo serviço para construção dos modelos tridimensionais virtuais (software InVesalius 3.0®). Com o software Rhinocerus 5.0® mensurou-se a lesão de HS e padronizou-se uma posição para aferição das seguintes medidas: a maior distância mediolateral, perpendicular ao eixo da diáfise, a distância craniocaudal, pararela à diáfise, e a maior distância numa linha imaginária no eixo longitudinal da lesão. Com impressora tridimensional Printer-ZP 310 confeccionou-se os protótipos em gesso. Usou-se paquímetro digital universal calibrado, para fazer as três medidas da lesão de HS pré-estabelecidas. As mensurações foram feitas por aferição cega. Resultados Houve grande variabilidade intraobservador e interobservador para as medidas em uma mesma peça. Os observadores não fizeram as medições de forma similar, o que caracteriza a existência de dificuldade da mensuração pelo método (p < 0,05). Nas mensurações no computador para aferição da distância mediolateral e na medição da peça com paquímetro, o tipo da peça influenciou a forma de feitura de medidas por cada um dos observadores, o que tornou o método de mensuração inválido (p < 0,05). Conclusão Não houve reprodutibilidade e repetibilidade nas mensurações da lesão de HS, tanto em modelos de gesso quanto nas imagens de reconstrução tomográficas.

Infections after shoulder arthroplasty are correlated with higher anesthetic risk score: a case-control study in Brazil

ABSTRACT Purposes: Shoulder arthroplasty (SA) has been performed by many years for the treatment of several conditions, including osteoarthritis and proximal humeral fractures following trauma. Surgical site infection (SSI) following Shoulder arthroplasty remains a challenge, contributing to increased morbidity and costs. Identification of risk factors may help implementing adequate strategies to prevent infection. We aimed to identify pre- and intra-operative risk factors associated with deep infections after Shoulder arthroplasty. Methods: An unmatched case-control study was conducted to describe the prevalence, clinical and microbiological findings, and to evaluate patient and surgical risk factors for prosthetic shoulder infection (PSI), among 158 patients who underwent SA due to any reason, at a tertiary public university institution. Risk factors for PSI was assessed by uni- and multivariate analyses using multiple logistic regression. Results: 168 SA from 158 patients were analyzed, with an overall infection rate of 9.5% (16/168 cases). Subjects undergoing SA with American Society of Anesthesiologists (ASA) grade III or higher (odds ratio [OR] = 5.30, 95% confidence interval [CI] = 1.58-17.79, p < 0.013) and presenting local hematoma after surgery (odds ratio [OR] = 7.10, 95% confidence interval [CI] = 1.09-46.09, p = 0.04) had higher risk for PSI on univariate analysis. However, only ASA score grade III or higher remained significant on multivariate analysis (OR = 4.74, 95% CI = 1.33-16.92, p = 0.016). Gram-positive cocci and Gram-negative bacilli were equally isolated in 50% of cases; however, the most commonly detected bacterium was Pseudomonas aeruginosa (18.7%). Conclusion: This study provides evidence suggesting that patient-related known factors such as higher ASA score predisposes to shoulder arthroplasty-associated infection. Furthermore, unusual pathogens associated with PSI were identified.