title: Involvement of the inconstant bursa of the fifth metatarsophalangeal joint in psoriatic arthritis: a clinical and ultrasonographic study.
abstract: OBJECTIVE
  To evaluate the involvement of the bursa located next to the head of the 5th metatarsal bone in patients with psoriatic arthritis (PsA) in comparison with the other seronegative spondyloarthritis (SpA).
  
  
  METHODS
  All patients with PsA seen during a period of 24 months were enrolled. The control group included healthy subjects and patients with the other SpA. All subjects underwent clinical and ultrasound (US) examination of the lateral surface of the 5th metatarsal.
  
  
  RESULTS
  150 PsA patients (88 M; 62 F), 172 SpA (107 M; 65 F), and 95 healthy controls (58 M; 37 F) were evaluated. Based on clinical and US evaluation, bursitis was diagnosed in 17/150 (11.3%) PsA patients but in none of the SpA (P < 0.0001) and healthy (P = 0.0002) controls. In detecting bursitis, US was more sensitive than clinical examination, although the difference did not reach statistical significance (P = 0.09).
  
  
  CONCLUSIONS
  The bursa of the 5th metatarsophalangeal joint appears to be involved in PsA more frequently than by chance. If confirmed by other studies, this finding could be considered as a distinctive clinical sign of PsA, useful for differential diagnosis with the other SpA. In asymptomatic patients, US proved to be more sensitive in the detection of bursitis.
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Giovanni
authors: G
authors: Ciancio
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Stefania
authors: S
authors: Volpinari
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Maria
authors: M
authors: Fotinidi
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Federica
authors: F
authors: Furini
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Ilaria
authors: 0000-0002-2965-0088
authors: I
authors: Farina
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Alessandra
authors: 0000-0003-2416-8134
authors: A
authors: Bortoluzzi
authors: Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Fossato di Mortara 64/b, 44121 Ferrara, Italy.
authors: Manuela
authors: 0000-0002-1595-6887
authors: M
authors: Ferracin
authors: Department of Internal Medicine, Rheumatology Division, University of Florence, Viale Pieraccini 18, 50139 Florence, Italy.
authors: Francesca
authors: F
authors: Bandinelli
authors: Department of Radiology, AUSL of Ravenna, Viale Stradone 9, 48018 Ravenna, Italy.
authors: Carlo
authors: C
authors: Orzincolo
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Francesco
authors: F
authors: Trotta
authors: Rheumatology Unit, Department of Medical Sciences, University of Ferrara and S. Anna University Hospital, Via Aldo Moro 8, 44124 Cona, Ferrara, Italy.
authors: Marcello
authors: 0000-0003-0499-5773
authors: M
authors: Govoni
mesh_terms: D000328:Adult; D000368:Aged; D015535:Arthritis, Psoriatic / Q000000981:diagnostic imaging*; D002061:Bursa, Synovial / Q000000981:diagnostic imaging*; D002062:Bursitis / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging*; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging; D014463:Ultrasonography