BACKGROUND: We assessed the accuracy of three different methods measuring the angle between two fixed Kirschner wires for the potential purpose of determining correction during rotational osteotomy of long bones. METHODS: Thirty-one orthopaedic consultants and registrars were prospectively asked to measure the angle between two fixed Kirschner wires in four saw bones models using three different techniques: visual estimation (VE), osteotomy templates (OT), and a contemporary smartphone (iPhone4; SP) with its gyroscopic function. These three methods were compared with the value obtained by computed tomography (CTV), which we considered the preferred value. RESULTS: For the pooled data for all four bone models, the mean difference of the VE compared with the CTV was 5.4° ± 5.3°; the mean difference of the OT compared with the CTV was 2.9 ± 3.8°; and the mean difference of the SP compared with the CTV was 0.8 ± 0.9°. Using the pooled data, the difference between using each of these methods was highly significant, as demonstrated by the one-way analysis of variance across groups (P ≤ 0.001). In addition, for the pooled data the independent t-test between each pair of the three methods (VE and OT, VE and SP, and OT and SP) also demonstrated these differences were highly significant (P ≤ 0.001) for all three comparisons. In this study, the number of years of orthopaedic experience did not significantly influence the ability of individual test subjects. CONCLUSION: Measurement of a rotational deformity using a SP app was significantly more accurate and consistent than both VE and OT. We believe the currently available SP technology provides orthopaedic surgeons with a significantly better alternative method of determining the magnitude of rotational deformity when performing corrective osteotomies.
BACKGROUND: We assessed the accuracy of three different methods measuring the angle between two fixed Kirschner wires for the potential purpose of determining correction during rotational osteotomy of long bones. METHODS: Thirty-one orthopaedic consultants and registrars were prospectively asked to measure the angle between two fixed Kirschner wires in four saw bones models using three different techniques: visual estimation (VE), osteotomy templates (OT), and a contemporary smartphone (iPhone4; SP) with its gyroscopic function. These three methods were compared with the value obtained by computed tomography (CTV), which we considered the preferred value. RESULTS: For the pooled data for all four bone models, the mean difference of the VE compared with the CTV was 5.4° ± 5.3°; the mean difference of the OT compared with the CTV was 2.9 ± 3.8°; and the mean difference of the SP compared with the CTV was 0.8 ± 0.9°. Using the pooled data, the difference between using each of these methods was highly significant, as demonstrated by the one-way analysis of variance across groups (P ≤ 0.001). In addition, for the pooled data the independent t-test between each pair of the three methods (VE and OT, VE and SP, and OT and SP) also demonstrated these differences were highly significant (P ≤ 0.001) for all three comparisons. In this study, the number of years of orthopaedic experience did not significantly influence the ability of individual test subjects. CONCLUSION: Measurement of a rotational deformity using a SP app was significantly more accurate and consistent than both VE and OT. We believe the currently available SP technology provides orthopaedic surgeons with a significantly better alternative method of determining the magnitude of rotational deformity when performing corrective osteotomies.
Authors: Ishaan Swarup; Christine Goodbody; Elizabeth Gausden; Douglas Mintz; David Scher; Roger Widmann Journal: J Clin Orthop Trauma Date: 2018-06-19