A 28-year-old male footballer presents to the emergency department with acute onset severe pain and swelling of the right knee after a sudden twisting injury during a match. Clinical examination reveals a positive anterior drawer sign and Lachman test. The knee is held in 20° flexion and the patient is unable to bear weight. What is the most appropriate immediate next step in management?

Explanation

## Clinical Assessment of Acute Knee Injury **Key Point:** In any acute knee injury with suspected ligamentous involvement, fracture must be excluded first before advanced imaging or intervention. ### Rationale for Correct Answer Plain radiographs (AP, lateral, and skyline views) are the appropriate immediate next step because: 1. **Fracture exclusion is paramount** — a twisting injury with inability to bear weight raises concern for associated fractures (tibial plateau, femoral condyle, fibular head). 2. **Cost-effective and rapid** — plain films can be obtained within minutes in the ED. 3. **Guides subsequent imaging** — if fractures are excluded, MRI can then be ordered to assess soft tissue (ACL, menisci, collateral ligaments). 4. **Standard protocol** — NEET PG and AIIMS exams emphasize the "rule out fracture first" principle in acute joint injuries. ### Management Algorithm for Acute ACL Injury ```mermaid flowchart TD A[Acute knee injury with positive drawer/Lachman]:::outcome --> B[Plain radiographs AP, lateral, skyline]:::action B --> C{Fracture present?}:::decision C -->|Yes| D[Orthopedic consultation, consider CT]:::action C -->|No| E[Ice, compression, elevation, immobilization]:::action E --> F[Clinical reassessment at 48-72 hours]:::action F --> G{Persistent instability?}:::decision G -->|Yes| H[MRI to confirm ACL tear]:::action G -->|No| I[Conservative management, physiotherapy]:::action H --> J[Orthopedic referral for surgical planning]:::action ``` **High-Yield:** The anterior drawer sign (tibia subluxates anteriorly) and Lachman test (most sensitive for ACL injury) are clinical indicators of ACL injury, but imaging must first exclude fractures that would change acute management. **Clinical Pearl:** A positive Lachman test in acute injury is highly specific for ACL tear, but the immediate priority is fracture exclusion because a missed tibial plateau fracture can lead to compartment syndrome or permanent disability. **Warning:** Do not order MRI immediately in the acute setting without first ruling out fracture — this delays diagnosis and increases cost. Immediate arthroscopic repair is not indicated in the acute phase; surgery is typically deferred 2–3 weeks to allow swelling to resolve and allow informed consent discussions.