S83.421A Sprain of lateral collateral ligament of right knee, initial encounter

Billable ICD-10-CM code, FY2026.

Built from S83.421 with 7th character A (initial encounter).

Applies from S83 Dislocation and sprain of joints and ligaments of knee

Includes

• avulsion of joint or ligament of knee
• laceration of cartilage, joint or ligament of knee
• sprain of cartilage, joint or ligament of knee
• traumatic hemarthrosis of joint or ligament of knee
• traumatic rupture of joint or ligament of knee
• traumatic subluxation of joint or ligament of knee
• traumatic tear of joint or ligament of knee

Excludes2 (not included here)

• derangement of patella (M22.0-M22.3)
• injury of patellar ligament (tendon) (S76.1-)
• internal derangement of knee (M23.-)
• old dislocation of knee (M24.36)
• pathological dislocation of knee (M24.36)
• recurrent dislocation of knee (M22.0)
• strain of muscle, fascia and tendon of lower leg (S86.-)

Code also

• any associated open wound

7th character note

• The appropriate 7th character is to be added to each code from category S83

7th character required

• A — initial encounter
• D — subsequent encounter
• S — sequela

Applies from S83.42 Sprain of lateral collateral ligament of knee

Applicable to

• Sprain of fibular collateral ligament

Code annotations containing back-references to S83.421A

Back-references to S83

• Type 2 Excludes: M23 Internal derangement of knee ("current injury - see injury of knee and lower leg (S80-S89)")
• Type 2 Excludes: S86 Injury of muscle, fascia and tendon at lower leg level ("sprain of joints and ligaments of knee (S83.-)")

Nearby codes

• S83.419A Sprain of medial collateral ligament of unspecified knee, initial encounter
• S83.419D Sprain of medial collateral ligament of unspecified knee, subsequent encounter
• S83.419S Sprain of medial collateral ligament of unspecified knee, sequela
• S83.42 Sprain of lateral collateral ligament of knee
• S83.421 Sprain of lateral collateral ligament of right knee
• S83.421A Sprain of lateral collateral ligament of right knee, initial encounter (this code)
• S83.421D Sprain of lateral collateral ligament of right knee, subsequent encounter
• S83.421S Sprain of lateral collateral ligament of right knee, sequela
• S83.422 Sprain of lateral collateral ligament of left knee
• S83.422A Sprain of lateral collateral ligament of left knee, initial encounter
• S83.422D Sprain of lateral collateral ligament of left knee, subsequent encounter