Background: The aim of this review was to qualitatively synthesise studies that have investigated characteristics of the first metatarsophalangeal joint (1(st) MTP) in gout and to undertake a meta-analysis to estimate the average prevalence of acute 1(st) MTP arthritis across studies in people with gout.
Methods: Studies published in English were included if they involved participants who had a diagnosis of gout and presented original findings relating to the following outcome measures associated with the 1(st) MTP: epidemiology; clinical features; structural and functional characteristics; and microscopic and imaging features.
Results: Forty-five studies were included in the qualitative synthesis. 1(st) MTP pain was a prominent feature in people with gout. People with 1(st) MTP gout reported walking- and general-disability. Structural and functional characteristics of 1(st) MTP gout included hallux valgus, osteoarthritis, and restricted joint motion. Successful crystal aspiration ranged from 81 to 91 % and positive crystal identification via microscopy ranged from 83 to 93 % in patients with a history of 1(st) MTP gout. Imaging features were common at the 1(st) MTP including the double contour sign, tophi and erosions. Eleven studies involving 2,325 participants were included in the meta-analysis, providing an estimate of the average prevalence of acute 1(st) MTP arthritis across studies of 73 % (95 % prediction interval 40-92 %; range 48-97 %; I(2) = 93 %).
Conclusions: 1(st) MTP acute arthritis is highly prevalent in people with gout and has a substantial impact on patient-reported pain and disability. Gout affects the structure and function of the 1(st) MTP. Microscopic and imaging studies have demonstrated crystal deposition and joint damage at the 1(st) MTP in people with gout.