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Total ankle arthroplasty is a useful surgical procedure for osteoarthritis of the ankle, but aseptic loosening of components is an issue. We report here a case of aseptic implant loosening with metallosis after total ankle arthroplasty using the TNK ankle (Kyocera, Kyoto, Japan), which occurred despite the components being ceramic. We also report favorable results from our method of treatment using a total talar prosthesis in the revision surgery. During the revision surgery, synovial metallosis was found, probably related to superficial damage to the screw affixing the tibial component to the bone. Because both the tibial and talar components were loose, all the components and the remaining talar bone were removed. A new tibial component and a custom-made alumina-ceramic total talar prosthesis was inserted. Pain relief was achieved and maintained through the latest follow-up visit at 42 months after revision surgery. Dorsiflexion of the ankle improved from 0° to 5° and plantarflexion remained unchanged from its preoperative range of 20°. The American Orthopaedic Foot & Ankle Society ankle-hindfoot score improved from 38 to 80 points. To the best of our knowledge, this is the first reported case of an alumina-ceramic total ankle prosthesis loosening caused by metallosis resulting from screw abrasion. Favorable treatment results were obtained by using a total talar prosthesis in the revision surgery., (Copyright © 2019. Published by Elsevier Inc.)

An association between the medial partite hallux sesamoid (MPHS) and hallux valgus (HV) has been suggested; however, a causal relationship has not been confirmed. This study aimed to determine their causal relationship using a cross-sectional radiographic survey of a large-scale population cohort covering a wide age group. The fifth survey of the Research on Osteoarthritis/Osteoporosis against Disability study involved 1997 participants aged 21–95 years who had undergone anteroposterior radiography of bilateral feet. The presence of MPHS, its morphology, and radiographic parameters related to the HV were assessed using radiographs. Changes in the prevalence of MPHS with age were assessed using trend tests. The relationship between the MPHS and HV was assessed based on sex and age. MPHS was found in 508 out of 3994 feet (12.7 %), with a significant difference in prevalence between men and women (10.0 % vs. 13.7 %, p < 0.001). Trend analysis demonstrated a significant decrease in MPHS occurrence with age in both sexes. HV angle was significantly higher in feet with MPHS than in those without (Men: 17.8 ± 7.0° vs. 14.0 ± 5.9°, p < 0.0001; Women: 19.6 ± 7.7° vs. 17.7 ± 7.9°, p < 0.0001). The prevalence of HV angle ≥ 20° was also significantly higher in feet with MPHS than in those without (Men: 33.3 % vs. 14.6 %, p < 0.0001; Women: 46.5 % vs. 34.6 %, p < 0.0001). This association between MPHS and HV was noticeable in younger adults and became less prominent with age. MPHS is associated with HV. The weakening of this relationship and the decreased prevalence of MPHS with age suggest that MPHS is not caused by HV, but is one of the causes of HV, especially in younger adults. • The causal relationship between hallux valgus and medial partite hallux sesamoid has not been elucidated. • This study surveyed their relationship using a large-scale population cohort. • Medial partite hallux sesamoid is associated with hallux valgus; however, their relationship was weakened with age. • The prevalence of medial partite hallux sesamoid decreased with age. • The findings from the present study suggested that medial partite hallux sesamoid is not caused by hallux valgus, but is one of the causes of hallux valgus, especially in younger adults. [ABSTRACT FROM AUTHOR]