Browsing by Author "Calvo M., Rafael"
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Item Biomechanical and geometric characterization of peroneus longus allografts with respect to age(2019) Wong, Andrew; Schaffler, Benjamin; Nixon, Ryan; Carrero, Leanza; Neufeld, Eric; Grande, Daniel; Calvo R., Rafael; Calvo M., RafaelBackground: Anterior cruciate ligament injuries are among the most common injuries in high impact sports, and reconstruction is the standard surgical procedure for these ruptures. Reconstructions are often performed using allografts rather than autografts on a case-by-case basis. Controversy exists as to whether or not age of donor tissue plays a factor in the mechanical properties of allografts. Methods: 38 peroneus longus (PL) tendons were prepared using the two-strand graft technique and then subjected to a cyclic loading test regimen of 1000 cycles to determine material properties. Specimens were grouped based on age to ascertain whether donor age affects the material properties of PL tendons. Findings: Secant modulus of the first cycle was determined to be 150.43 (SD 40.24) MPa. The average magnitude of the dynamic modulus was determined to be 82.81 (SD 24.65) MPa. Specimens were grouped into three distinct groups for analysis (x < 40 yo, 40 yo ≤ x < 60 yo, 60 yo < x). Interpretation: The need for using intrinsic material properties is highlighted. There is no significant difference in any intrinsic material property with respect to age or the fatigue of the tendon as the cycle count increases. Conversely, the measured stiffness of a tendon decreased as function of age with a large effect size. Based on analysis of graft geometries, it was determined that PL tendons become significantly more slender with increased age which result in the observed decrease in stiffness.Item Prediction of semitendinosus-gracilis graft diameter in children and adolescents using anthropometric measures.(Springer International Publishing AG, 2016) Calvo R., Rafael; Espinosa, Maximiliano; Figueroa, David; Calvo M., RafaelPURPOSE: The aim of this study was to evaluate whether the anthropometric and demographic measures of patients under 18 years can be used to predict the diameter of STG autograft in ACL reconstruction surgery. METHODS: Retrospective series of 169 patients under 18 years (112 men, 57 women, average age 15.8 years) underwent ACL reconstruction surgery with STG autograft. We recorded anthropometric measures (weight, height and BMI), demographics (age and gender) and autograft diameter used. Correlation coefficients, linear regression and unpaired t test were used to determine the relationship between anthropometric/demographic variables and the diameter of the graft. p values <0.05 were considered statistically significant. RESULTS: Correlation analysis showed a significant positive relation between height and graft diameter (r = 0.483, p < 0.0001) as well as between weight and graft diameter (r = 0.248, p = 0.001). However, age and BMI did not correlate with graft thickness (r = 0.098 and p = 0.203, r = 0.009 and p = 0.905, respectively). The mean graft diameter in men was 8.2 (range 6-10) and 7.5 in women (range 6-9), a difference that was statistically significant (p < 0.001). CONCLUSIONS: Prediction of the STG graft diameter according to the height of the patient is an easy and reliable method in children and adolescents. These data may provide relevant preoperative information about the need of an alternative graft source and can be useful when counselling patients.