Background: An increasing number of institutions convert to digital radiography for diagnostic and surgical decisions. It can be foreseen that the benefit of these systems will be continual to both doctors and patients. Aside from preoperative planning, operative versus nonoperative decisions that require a known measurement to be identified and compared to acceptable values can be done using this system. It is therefore crucial that the accuracy of the system be validated for doctors to provide the best care and advice for our patients.
Methods: In the first phase of this investigation, the postoperative digital radiographs of 27 patients who underwent intramedullary nailing of their tibial or femoral shaft fractures in DLSUMC were retrieved. Using the digital radiography system, the tibial nail lengths were determined using the "measure length" tool and compared to the actual implant length placed as recorded on the operative technique.
In the second phase of the investigation, 5 cadaveric tibias and 5 cadaveric femurs were acquired and measured directly using specified bony landmarks proximally and distally. Digital radiographs of the cadaveric bones were then taken and digitally measured using the same bony landmarks. Direct and digital measurements were then compared. Both phases of the study were analyzed using the Bland-Altman Agreement Method.
Results: 100% of the digital measurements taken were inaccurate. Digital measurements from both the femur and tibia are systematically biased towards a larger measurement as compared to the actual length by an average of 2.31 cms although linear relationship was noted. All data are statistically significant but not always clinically significant.
Conclusion: The digital radiography system in DLSUMC can be used as pre-operative measurement tool for intramedullary nail determination in the lower extremities, just as long as the sizes immediately smaller to the digitally measured size are available just in case.