Objectives To evaluate the ankle, hindfoot, and heel changes (determined by physical examination, ultrasound and baropodometry) in patients with rheumatoid arthritis, to compare the findings with healthy subjects, and to analyze if these findings are associated with ankle pain and could affect the quality of life. Methods We enrolled 35 rheumatoid arthritis patients and 35 healthy controls, and evaluated their ankles (tibiotalar joints, tendons), hindfeet (talonavicular, subtalar joints) and heels using clinical examination, DAS28-CRP, RAPID3 for the evaluation of functional status, quality of life in rheumatoid arthritis questionnaire, ultrasound, and baropodometry. Results The ultrasound inter-observer agreement was good for the subtalar joint, and very good for the other structures. Flat foot was identified in 50% of feet in rheumatoid arthritis patients, with 83.8% having concomitant hindfoot valgus and less subtalar joint synovitis visible from the lateral approach (32.4% vs 55.6%, p = 0.041). The body mass index, RAPID3 and subtalar synovitis were independent predictors for the symptomatic ankle (all p <0.05). Midfoot and heel plantar pressures were higher in rheumatoid arthritis patients compared to healthy controls, but when subtalar synovitis was present, the pressures decreased (avoidance of heel support). Poor quality of life in rheumatoid arthritis patients was independently predicted by DAS28-CRP, RAPID3, disease stage, hindfoot valgus, tibiotalar and subtalar synovitis, tendon pathology, Achilles tendon enthesophytes, calcaneal erosions, plantar fasciitis, and perifasciitis (all p <0.05). Conclusion The quality of life of rheumatoid arthritis patients is significantly affected by ankle and hindfoot pathology (inflammatory modifications, but also degenerative findings and deformities). Ultrasound scanning is an important tool in the evaluation of inflammatory and degenerative lesions in these regions, and their early detection might contribute to a better therapeutic management in these patients.

Aim: To compare the ultrasonography (US) performance with magnetic resonance imaging (MRI) in identifying pathology in ankles, hindfeet and heels of rheumatoid arthritis (RA) patients and to evaluate the reasons for discordances between the two imaging methods.Material and methods: RA patients were enrolled and evaluated using the Clinical Disease Activity Index (CDAI) and the Disease Activity Score 28 with C-reactive Protein (DAS28-CRP). The ankle (tibiotalar joint, tendons), hindfoot (talonavicular, subtalar joints) and heel of the most symptomatic or dominant foot (for the asymptomatic patient)were evaluated by two pairs of examiners using US and contrast-enhanced MRI.Results: Totally, 105 joints, 245 tendons and 35 heels in 35 patients [mean age 59.2±11.25 years old, median disease duration 36 (16.5-114), mean CDAI 19.87±12.7] were evaluated. The interobserver agreements between the two sonographers, and the two radiologists were good and very good (k=0.624-0.940). The overall agreement between US and MRI was very good for subcalcaneal panniculitis (k=0.928, p<0.001), moderate for synovitis (k=0.463, p<0.001) and tenosynovitis (k=0.514, p<0.001), fair for osteophytes (k=0.260, p=0.004), and poor for erosions (k=0.063, p=0.308) and heel’s structures. MRI found more erosions, synovitis, osteophytes,tenosynovitis and retrocalcaneal bursitis, but US found more enthesophytes and plantar fasciitis. Many of the discordancesbetween the two imaging techniques have explanations related to the technique itself or definition of the pathologic findings.Conclusions: US is comparable to MRI for the evaluation of ankle, hindfoot and heel in RA patients and discordances in theinterpretation of the pathological findings/normal structures must be carefully analyzed.

Primary synovial osteochondromatosis is a rare disorder and its diagnosis remains a challenge to the physician. We present the case of 36 year old patient with right knee monoarthritis in which ultrasound findings, corroborated with clinical and histopathological evidence confirmed the diagnosis of unossified primary synovial osteochondromatosis. The arthroscopy with synovectomy found multiple intra-articular loose bodies occupying the entire joint. The ultrasonographic findings were extensively evaluated.