This study aims to compare digital tomosynthesis with radiography and weight-bearing CT as an imaging technique to assess arthritis in the foot and ankle.

The overall goal of this study is to improve radiologic evaluation of foot and ankle arthritis. Today's standard of care, radiography, provides limited two-dimensional evaluation of joint alignment, arthritic changes, posttraumatic changes, and congenital deformities due to overlapping bone densities. Evaluation is even more limited in post-surgical patients due to overlapping metallic hardware. Computed tomography (CT), the current problem-solving tool, offers more "level-by-level" three dimensional information, but is fraught with additional cost, additional radiation dose, beam-hardening artifacts from hardware, and the need for additional equipment. Most importantly, patients are not weight-bearing during conventional CT, therefore masking the true extent of malalignment or arthritic joint space narrowing. At the University of Washington, physicians attempt to overcome the last problem by performing simulated weight-bearing CT. The study proposes an alternate solution to this problem using a novel application of an old method, digital tomosynthesis. Specific aims of the study are 1) to compare radiography, tomosynthesis, and simulated-weight bearing CT in their ability to detect foot/ankle malalignment, 2) to compare the abilities of these three modalities to detect arthritis changes such as joint space narrowing, osteophytes, and subchondral cysts, and 3) to compare their abilities to detect bony deformities such as acute fracture, old fracture deformity, or partial fusion (post traumatic or post surgical). Radiographic assessment will be correlated with clinical outcome using clinical notes and functional outcome such as the Lower Extremity Functional Scale (LEFS) questionnaire. Successful results from this initial study will have the potential to change practice paradigm in how to image foot and ankle arthritis.

Inclusion Criteria:

1. adult age (18 years or older)
2. clinical orthopedic surgery follow-up notes available at University of Washington
3. ability to complete the Lower Extremity Functional Scale (LEFS) or equivalent questionnaire at the time of the study, a well established survey to test for functional ability in lower extremity

Exclusion Criteria:

1. inability to use the simulated weight bearing CT machine due to pain
2. prior complete osseous fusion of foot/ankle joints
3. prior total ankle arthroplasty
4. Pregnancy