Differential Diagnosis and the Diagnostic Pathway

A bucket handle tear is unlikely without new trauma. A cyclops lesion, which almost always follows ACL reconstruction, causes painful loss of extension and should prompt an MRI and referral at three to four weeks. A graft placed too far anterior relative to Blumensaat's line blocks extension and may need staged revision, and a partially torn graft flap acts as a mechanical block. CRPS is rare and is often diagnosed when the Budapest criteria are not met. Patients should be taught before surgery to go straight to the emergency department if the knee suddenly loses range, swells, turns red or the calf hurts, since infection and blood clots are urgent. A total knee replacement that is still stiff months later but shows no warmth, swelling or fever points toward implant loosening rather than infection. The IAA pathway separates active from residual arthrofibrosis. In active cases infection is ruled out first, then physiotherapy with progressive stretching and medication, and surgery if that fails.