Evaluating the accuracy of the orthopedic eye

Abstract

Purpose: Orthopedic surgeries are still dependent on the human factor and more specifically the human eye to gauge the end result. Thus, the planned result and the final surgical result may differ at times. Our hypothesis was that the human eye would not be able to distinguish any angulational difference <3° from the planned trajectory. Materials and Methods: A cross-sectional study in the form of an online survey was conducted. Five clinical scenarios (each with seven variations) that require judgment of angles were recreated. Thirty-five yes or no statements were tested. Results were collected and analyzed statistically. Results: Seventy-four respondents completed the survey. The mean responded age was 42.8 years (standard deviation [SD]: 11.2, range: 28–80). The average of years in practice as a doctor (but not yet a specialist) was 8.3 years (SD: 2.1, range: 4–11), and the median number of years after qualifying as an orthopedic surgeon was 9.0 years (interquartile range, 5.0–17.5). The highest frequencies of inaccuracies occurred around the 1° error margin for all scenarios. Although specialists appeared to score higher (66.6 ± 7.3%) than trainees (62.9 ± 11.4%), this difference was not significantly different (P = 0.107). Conclusion: Orthopedic surgeons can distinguish alignment differences of <3° if the reference framework is perfectly orthogonal and parallel. If the reference framework is rhomboid (skewed) then gauging angles of <3 degrees off it, especially if the angle being gauged is on the same side as one of the acute angles formed by the reference framework.