CASE 9764 Published on 15.12.2011

Case of a painful toe


Musculoskeletal system

Case Type

Clinical Cases


Sangeetha Govinda Rajoo1, Sivadas Ganeshalingham2

(1) E-Learning Fellow, Barts & The London School of Medicine, Queen Mary University of London, Whitechapel.
(2) Consultant Radiologist, Barts & The London NHS Trust, Whitechapel.

Barts & The London NHS Trust,
Queen Mary University of London,
Centre of Medical Education; Room 3.10,
Garrod Building, Turner Street
E1 2AD London;

39 years, male

Area of Interest Musculoskeletal bone, Anatomy, Musculoskeletal soft tissue ; Imaging Technique MR
Clinical History
A 39-year-old HIV negative, intravenous drug abuser presented with left toe pain. He was pyrexial and unwell. On examination, there was erythema and tenderness over the 1st metatarsophalangeal joint with a reduced range of movement. No rash, or joint swelling was present.
Imaging Findings
A radiograph of the left foot showed minor great toe metatarsophalangeal joint degenerative changes. Due to persistent symptoms of foot pain, an MRI was requested. The MRI showed T1 hypointensity within the medial sesamoid. There was increased signal on the PD fat saturated sequences. In addition there was a metatarsophalangeal joint effusion with synovitis and inflammatory changes around the sesamoids. Post contrast administration there was enhancement of the inflammatory soft tissue but no focal collection. There was also tenosynovitis of the flexor tendon of the great toe.

Impression: The findings were consistent with osteomyelitis of the medial sesamoid.
Painful conditions of the sesamoid complex can be due to a variety of causes including congenital, traumatic, arthritic, infectious and ischaemic conditions [1, 2].
The complex anatomy and pain-sensitive structures in the region can make diagnosis difficult [2, 3]. Whilst clinical and laboratory findings should initially be performed and considered, imaging plays a crucial role in identifying the pathology.
Conventional radiography is the initial imaging modality, including lateral and dorsoplantar views as well special axial projections of the sesamoid bones [3]. If inconclusive, MRI should be performed next. Optimal planes for imaging the sesamoids are short axis and sagittal sequences.
T1, T2 fat sat (or STIR) and T1 fat sat post gadolinium sequences should be performed in cases of suspected osteomyelitis. In osteomyelitis, the MR findings would include foci of low signal intensity marrow on T1-weight spin-echo images and high signal intensity marrow on T2 FS-weighted and STIR images [2]. If oedema is seen only on T2-FS weighted images with or without enhancement, a false positive diagnosis of osteomyelitis can be made. If these changes are present with normal T1 marrow signal intensity, then this may represent reactive marrow oedema rather than infection [2]
Osteomyelitis and septic arthritis can affect the sesamoid complex, commonly through direct contiguous seeding from diabetic foot ulcers [1]. Haematogenous spread can happen in children, young adults and IV drug abusers [1, 4]. The commonest causative organism amongst IV drug abusers is Staphylococcal Aureus [4, 5]. Antibiotic treatment should be based on culture results and susceptibility of causative organism. This patient was treated with a combination of flucloxacillin, benzylpenicillin and fusidic acid for 6 weeks. Treatment can also involve surgical intervention with debridement of involved structures [1, 6].
Differential Diagnosis List
Osteomyelitis of the medial sesamoid
Congenital: Painful partite sesamoid
Painful anatomic variations
Trauma: Fracture
Arthritis: Osteoarthritis
Rheumatoid arthritis
Seronegative spondyloarthropathies and crystal deposition gout
Infection: Septic arthritis
Ischaemia: Osteonecrosis [3]
Final Diagnosis
Osteomyelitis of the medial sesamoid
Case information
DOI: 10.1594/EURORAD/CASE.9764
ISSN: 1563-4086