Our objectives were to validate a protocol for evaluating femoral alignment in dogs with MPL using CT and use it to design and report the accuracy and repeatability of a 3D-printed DFWO guide and plate system. The angles evaluated were aLDFA including FVA, FCT, AA, IA and NAA. Repeatability for all measurements ranged from moderate (ICC = 0.65) to excellent (ICC = 0.96). Reliability ranged from good (ICC = 0.79) to excellent (ICC = 0.99). Seven femurs had varus/valgus (aLDFA) corrected to 95 and torsion (AA) corrected to 30. The mean difference between the target and achieved was 1.29° (+/-3.58°, p = .085) for aLDFA and 3.43° (+/-5.21°, p = .012) for AA. The intraobserver ICCs for aLDFA and AA were 0.865 and 0.817, respectively. The measurement protocol was repeatable and reliable and the DFWO system provided accurate and repeatable correction of frontal plane deformities but not torsional deformities.