Digital subtraction radiography, tomosynthesis, bone uptake of radionuclide, and arthroscopy were evaluated for detection and quantification of bony lesions induced unilaterally in the condyles of six dogs. A stereotaxic head-holder facilitated acquisition of reproducible radiographs suitable for subtraction and for circular tomosynthesis. Bone uptake of technetium-99m methylene diphosphonate was measured with a hand-held collimated miniature detector. Arthroscopy was performed with an arthroscope of 2.4 mm diameter. Bone defect mass determined by subtraction radiography correlated highly (r = 0.92, p less than 0.001) with the calcium content of removed bone measured by atomic spectroscopy. Both subtraction radiography and tomosynthesis indicated reshaping of the condyle into a more anterior position over a 10-week follow-up period. Radionuclide uptake was significantly elevated (p less than 0.04) from 2 to 10 weeks after surgery and correlated (r = 0.73, p less than 0.05) with regained bone mass measured by subtraction radiography. Arthroscopy revealed progressive degeneration of cartilage with denudation in the fossa. Both radiographic techniques demonstrated the lesions and bone remodeling, but only subtraction provided quantitative results. Radionuclide uptake predicted quantitatively future bone mass changes, and arthroscopy revealed cartilage and soft tissue status not otherwise observable.