Partial Loss of Signal in the Sinus Tarsi in a 60-Year-Old Man
Yes, partial loss of signal intensity in the sinus tarsi on MRI is common in a 60-year-old man and is frequently a secondary finding related to underlying ankle pathology rather than an isolated age-related change.
Understanding the Finding
Signal alterations in the sinus tarsi represent a spectrum of pathologic changes that are highly prevalent in patients undergoing ankle MRI. In a study of 123 ankle MRI examinations, abnormalities of the tarsal sinus and canal were identified in 26.8% of cases 1. These changes typically manifest as:
- Diffuse infiltration with low T1- and T2-weighted signal intensity (consistent with fibrosis)
- Low T1-weighted signal with increased T2-weighted signal (consistent with chronic synovitis and inflammatory changes)
- Multiple fluid collections (synovial cysts) 1
Clinical Significance and Associated Pathology
The key clinical insight is that sinus tarsi signal abnormalities are rarely isolated findings. Research demonstrates that all patients with ganglia and degenerative changes in the tarsal sinus presented with another pathology at the ankle, suggesting that sinus tarsi degeneration is a secondary phenomenon due to pathologic biomechanics elsewhere in the hindfoot 2.
Common Associated Conditions:
- Lateral collateral ligament injuries - highly associated with sinus tarsi abnormalities, with scarring of the anterior talofibular and fibulocalcaneal ligaments found in 68% and 72% of patients respectively 2
- Posterior tibial tendon pathology - ganglia at the retinacula show strong association with synovitis and tendinosis 2
- Ligamentous degeneration - signal alterations suggesting degeneration were found in 85% of interosseous ligaments, 50% of cervical ligaments, and 63% of retinacula 2
Age-Related Context
At 60 years old, the likelihood of degenerative changes increases due to cumulative microtrauma, previous ankle injuries (which may not have been clinically significant enough to be remembered - only 27% of patients with ligamentous scarring recalled ankle sprains 2), and age-related tissue degeneration.
Clinical Pitfalls to Avoid
Do not dismiss sinus tarsi signal abnormalities as merely incidental or age-related. When you identify these changes, actively search for:
- Lateral ankle ligament pathology (anterior talofibular, calcaneofibular, fibulocalcaneal ligaments)
- Posterior tibial tendon abnormalities
- Subtalar joint osteoarthritis
- Hindfoot biomechanical abnormalities
The finding should prompt a thorough evaluation of the entire ankle and hindfoot complex on MRI, as the sinus tarsi changes likely reflect underlying mechanical dysfunction 2, 3.