Patient presents with complaints of left knee pain and instability consistent with a left knee sprain.  Onset of symptoms occurred on [Date of Injury] during [Mechanism of Injury - e.g., twisting injury while playing basketball].  Patient denies any popping or audible click at the time of injury.  Pain is localized to the [Medial, Lateral, or Generalized] aspect of the left knee and is characterized as [Sharp, Dull, Aching, Throbbing].  Patient reports [Mild, Moderate, Severe] pain, rated [Pain Scale 0-10].  Swelling is [Present/Absent] and [Mild, Moderate, Severe] if present.  Ecchymosis is [Present/Absent].  Range of motion is limited due to pain, with noted difficulty with [Flexion, Extension].  Ligamentous testing reveals [Specific findings, e.g., tenderness to palpation over the medial collateral ligament, positive valgus stress test at [degrees], suggesting a Grade [I, II, III] MCL sprain].  No obvious deformity is noted.  Neurovascular examination of the left lower extremity is intact.  Differential diagnosis includes left knee sprain, meniscus tear, fracture.  Initial treatment includes RICE therapy (rest, ice, compression, elevation), NSAIDs for pain management, and referral to physical therapy for rehabilitation.  Radiographs of the left knee were obtained to rule out fracture and showed [Results of imaging - e.g., negative for fracture].  Patient was instructed to follow up in [Duration] for reassessment and further management.  Diagnosis: Left knee sprain.  ICD-10 code: [Appropriate ICD-10 code, e.g., S83.402A - Sprain of unspecified ligament of left knee, initial encounter].