M25.461 Effusion, right knee

Billable ICD-10-CM code, FY2026.

Applies from M25 Other joint disorder, not elsewhere classified

Excludes2 (not included here)

• abnormality of gait and mobility (R26.-)
• acquired deformities of limb (M20-M21)
• calcification of bursa (M71.4-)
• calcification of shoulder (joint) (M75.3)
• calcification of tendon (M65.2-)
• difficulty in walking (R26.2)
• temporomandibular joint disorder (M26.6-)

Applies from M25.4 Effusion of joint

Excludes1 (never code together)

• hydrarthrosis in yaws (A66.6)
• intermittent hydrarthrosis (M12.4-)
• other infective (teno)synovitis (M65.1-)

MS-DRG index

Defines the logic of DRG(s) 564-566 in MDC 08.

Approximate ICD-9-CM (GEMs)

• 719.06 Effusion of joint, lower leg (approximate)

Code annotations containing back-references to M25.461

Back-references to M25.4

• Type 1 Excludes: R22 Localized swelling, mass and lump of skin and subcutaneous tissue ("swelling of joint (M25.4-)")

Nearby codes

• M25.45 Effusion, hip
• M25.451 Effusion, right hip
• M25.452 Effusion, left hip
• M25.459 Effusion, unspecified hip
• M25.46 Effusion, knee
• M25.461 Effusion, right knee (this code)
• M25.462 Effusion, left knee
• M25.469 Effusion, unspecified knee
• M25.47 Effusion, ankle and foot
• M25.471 Effusion, right ankle
• M25.472 Effusion, left ankle