Abscess of tendon sheath, unspecified ankle and foot

This code describes an infection with pus formation within the synovial sheath surrounding a tendon in an unspecified ankle or foot. This condition is characterized by localized inflammation, pain, swelling, and often impaired tendon function due to the infectious process. It represents a bacterial infection that has progressed to abscess formation within the tendon's protective covering.

Use this code when documentation clearly indicates an abscess involving a tendon sheath in the ankle or foot, but the specific laterality (right or left) is not specified. This diagnosis is typically supported by clinical examination findings of localized tenderness, fluctuance, and signs of infection, often confirmed by imaging or surgical exploration.

• Ensure documentation explicitly states "abscess of tendon sheath" and specifies the ankle or foot region.
• If laterality (right or left) is documented, use the more specific codes M65.071 (right) or M65.072 (left).
• Do not confuse with tenosynovitis without abscess (M65.87-) or other soft tissue abscesses not specifically involving a tendon sheath.