Biomedical subjects
Publications and source records attributed to Stuart Wertheimer.
In-training are one way to evaluate the residents during their training. Currently, the American Board of Podiatric Surgery supplies the examination. Various residency directors were questioned regarding its use and importance.
The purpose of this study was to assess 4 methods of fixation for the offset V osteotomy. Maximum load, failure energy, and stiffness were determined in a control group and in 4 different test models. There were 10 specimens for each group. The control group consisted of intact first ray sawbones. An offset V osteotomy was performed on each specimen in each of the 4 test groups. The osteotomies were fixated either with two 2.0-mm cortical screws, two 2.7-mm cortical screws, two 3.5-mm cortical screws, or one 2.7-mm cortical screw and a 0.045-in Kirschner wire, respectively. Each model was then loaded to failure with a computerized hydraulic-tensile testing machine. Results for maximum load to failure for all 4 fixation constructs showed a mean ranging from 113.0 to 144.0 N, a mean energy to failure ranging from 272.2 to 365.0 J, and a mean stiffness ranging from 21.3 to 27.0 N/mm. There were no statistically significant differences detected among the individual constructs. In the group fixated with 3.5-mm screws, there were statistically significant differences in all 3 parameters compared with the control group. In the groups fixated with 2.7-mm screws, 2.0-mm screws, and the 2.7-mm screw and Kirschner wire, there were statistically significant differences in the maximum load and the failure energy, but not in stiffness, when compared with the control group. These findings suggest that all 4 constructs provide similar mechanical properties when utilized for the fixation of the offset V osteotomy.
The effect of shear stress on a fixated distal syndesmosis of the ankle was evaluated with a servohydraulic materials-testing machine. Eighteen syndesmoses were fixated in a quadricortical technique using 3.5-mm cortical and 4.5-mm cortical stainless steel screws. A shear stress was applied via an axial load in an attempt to simulate weightbearing. The 4.5-mm quadricortical screws produced a higher yield load and peak load (484.3 +/- 93.8 N and 597.7 +/- 81.4 N) when compared with the 3.5-mm quadricortical syndesmotic screws (412.8 +/- 55 N, P = .033 and 511.2 +/- 64.4 N). These findings suggest that a larger diameter screw provides greater resistance to an applied shear stress at the distal syndesmosis.
The purpose of this study was to compare the mechanical properties of 3 osteotomies often used for hallux rigidus. Maximum load, failure energy, stiffness, and fracture pattern were determined for 3 different test models as well as a control group. Twenty-eight first metatarsal polyurethane sawbone models were equally divided into 4 groups. The osteotomy groups tested consisted of a Youngswick, sagittal V, and modified Weil-type osteotomy of the first metatarsal. Each osteotomy was fixated with a 2.7-mm cortical screw, all 16 mm in length, and a small diameter smooth wire, both placed perpendicular to the osteotomy. Each model was then loaded to failure in a servo-hydraulic material testing machine. Results for maximum load to failure for all 4 constructs showed a mean range of 15.1 to 33.7 N, a mean energy to failure ranging from 0.04 to 0.8 J, and stiffness from 1.5 to 3.4 N/mm. Significant differences in peak load and stiffness (P = .015 for peak load, P = .025 for stiffness) were found between the sagittal V group versus the control and between the modified Weil and sagittal V group (P = .037 for peak load, P = .017 for stiffness). There were no significant differences in the energy to failure between the 4 groups (P > .083). These findings suggest that the sagittal V osteotomy construct was significantly weaker and less stiff than the modified Weil.