Patient presents with complaints of right knee pain and instability following a non-contact twisting injury sustained while playing basketball.  The patient reports hearing a popping sensation at the time of injury followed by immediate swelling and difficulty bearing weight.  Physical examination reveals tenderness along the joint line, positive Lachman test, positive anterior drawer test, and a positive pivot shift test, suggestive of an anterior cruciate ligament (ACL) tear.  McMurray's test is negative, ruling out meniscus tear.  Range of motion is limited due to pain and swelling.  An MRI of the right knee is ordered to confirm the diagnosis and assess the extent of the injury, including any associated ligamentous or meniscal damage.  Differential diagnoses include meniscus tear, medial collateral ligament (MCL) sprain, and patellar tendonitis.  Preliminary diagnosis is right anterior cruciate ligament (ACL) rupture.  Treatment plan includes RICE (rest, ice, compression, elevation), pain management with NSAIDs, and referral to orthopedics for further evaluation and consideration of surgical intervention, such as ACL reconstruction.  Patient education provided on ACL injury, rehabilitation, and postoperative recovery.  Follow-up appointment scheduled in one week to review MRI results and discuss treatment options with the patient.  ICD-10 code S83.511A, right knee ACL rupture, is documented.