CASE 13228 Published on 16.02.2016

HIV-related osteonecrosis of the ankles and feet


Musculoskeletal system

Case Type

Clinical Cases


Ambra Sangiovanni, M.D., Enrico Colli Tibaldi, M.D., Ferdinando Draghi, M.D.

Radiology Institute, IRCCS Policlinico San Matteo Foundation, University of Pavia - Viale Camillo Golgi 19, 27100 Pavia, Italy

50 years, female

Area of Interest Musculoskeletal system ; Imaging Technique MR
Clinical History
A 50-year-old woman, HIV-positive, receiving HAART (highly active antiretroviral therapy), presented with atraumatic pain and swelling in both the ankles and feet, which she had had for years and which had recently become acute. She had never received corticosteroids and there were no other risk factors.
Imaging Findings
Ultrasound and X-ray did not show pathological features.
Magnetic resonance imaging (MRI) was performed using a Symphony Magnetom Maestro Class 1.5-T MRI system (Siemens Medical Solutions, Malvern, NJ, USA). Sagittal T1-weighted, sagittal, coronal and axial DP fat sat sequences were performed. Bilaterally, MRI showed areas of abnormal signal, with irregular margins in the distal third of the tibia, in the astragalus and calcaneus, related to severe subchondral ischaemia and bone oedema, suggesting osteonecrosis.
Tibio-astragalic and subastragalic joint effusion and insufficiency fractures of both the astragalus bones and of the proximal epiphysis of left tibia coexisted.
Osteonecrosis (or ‘avascular necrosis of bone’) derives from the death of cellular elements of bone causing skeletal pain. It is supposed to be the result of the interruption of the blood supply to the affected bone [1] and it has been attributed to: altered arterial blood viscosity, impaired arterial blood supply, the replacement of intraosseous vascular tissue with non-vascular tissue, a decreased arterial inflow due to increased intraosseous pressure, or hypertension caused by reduced venous drainage [2].
Alcohol abuse, dyslipidaemia, haemoglonbinopathies, hypercoagulable states and systemic corticosteroids are the most common risk factors for osteonecrosis.

Osteonecrosis is described as a rare complication in patients with HIV [3-4], with unclear and multifactorial pathogenesis [2-3]. The main risk factors are: anti-phospholipid and anti-cardiolipin antibodies [5], increased triglycerides, chronic treatment with steroids or megestrol acetate, caloric deprivation [2-6], and the use of protease inhibitors [7].
The role of HAART, instead, is still controversial.
It has been associated with several metabolic complications, determining osteopenia and osteoporosis [8]. The mechanisms involved are: (1) enhanced humoral immunity, causing increased production of anti-protein S or antiphospholipid antibodies; (2) hyperlipidemia and (3) abnormal fat distribution [9-10-1], which determine peripheral insulin resistance, inhibition of lipoprotein-lipase (by TNF-α), suppression of HIV replication and changes in endocrine homeostasis [11]. Immunomodulating effects are also associated with rise in serum osteocalcin levels [12].
In HIV-infected patients, bone disease can affect one or multiple sites and causes pain and swelling of the joints involved. In particular, in the English language literature, the hip represents the most common site of involvement, followed by the knee and the shoulder [7], while the ankle, especially bilaterally, is very rarely involved.

MRI and scintigraphy are currently the best methods to recognize the condition and establish a correct diagnosis [3], while the role of conventional X-ray and ultrasound appears unremarkable.
MRI can show several pathological features, which can be surely related to ischaemia, suggesting osteonecrosis.

MRI appears to be the most reliable and safe imaging technique available in the recognition of osteonecrosis.
Moreover, it has been suggested that systemic corticosteroids can represent a risk factor for osteonecrosis. In spite of this, our patient has received HAART, but has never been treated with corticosteroids.

Awareness of its potentiality should induce MRI to be encouraged as a valid method to diagnose osteonecrosis.
In addition, clinicians should be aware that HAART can play a leading role in determining the onset of osteonecrosis in HIV-infected patients, independently of other risk factors, especially systemic corticosteroids.
Differential Diagnosis List
HIV-related osteonecrosis of the ankles and feet
Osteochondral fracture [13]
Osteoarthritis [13]
Neuropathic osteoarthropathy [13]
Final Diagnosis
HIV-related osteonecrosis of the ankles and feet
Case information
DOI: 10.1594/EURORAD/CASE.13228
ISSN: 1563-4086