Osteoarthritis of the Foot and Ankle

Abstract

Foot osteoarthritis (OA) is a sometimes overlooked condition despite its high prevalence. Studies on foot OA are relatively limited and use inconsistent definitions and diagnostic criteria. The imaging criteria and grading of OA rely on anatomic changes on X-rays, such as joint narrowing and osteophytes. The two systems which are used for foot OA are the Kellgren and Lawrence grading system and the LaTrobe Foot Atlas. The most commonly foot joints affected by osteoarthritis are the 1st metatarsophalangeal joint (MPJ), the first and second cuneometatarsal joints (CMJ), the navicular-first cuneiform joint (N1st CJ), and the talonavicular joint (TNJ). According to available guidelines, bone scintigraphy with radiolabeled bisphosphonate is indicated for tarsal osteoarthritis. Bone SPECT/CT should be used to resolve diagnostic ambiguity in patients with midfoot pain after clinical examination and first-line imaging. However, there are scarce published data on the utility of bone SPECT/CT in other foot joints or on the utility of three-phase bone scintigraphy. Evidence from available data shows that SPECT/CT in patients with foot OA who are eligible for targeted joint injections succeeds in accurately identifying the appropriate target joint and changes the intended target site in a significant proportion of patients. In the postoperative setting, bone SPECT/CT may be used to identify pain generators, such as loosening or infection related to fixation screws or joint replacements or OA in joints adjacent to the surgical site.