A systematic approach ensures accurate knee injury diagnosis.
1. History
- Mechanism (twist, direct blow, hyperextension, overuse).
- Timing (acute vs. chronic), “pop” sensation, swelling onset (rapid = hemarthrosis).
- Functional limitations (instability, locking, giving way).
- Prior injuries/surgeries.
2. Physical Examination
- Inspection: Effusion, ecchymosis, deformity, muscle atrophy.
- Palpation: Joint lines, patella, collateral ligaments, pes anserine, tibial tubercle.
- ROM: Active/passive flexion/extension.
- Special Tests:
- Lachman, Anterior Drawer, Pivot Shift → ACL.
- Posterior Drawer, Dial Test → PCL/PLC.
- Varus/Valgus Stress → MCL/LCL.
- McMurray, Thessaly, Apley → Meniscus.
- Patellar apprehension, J‑sign → Patellofemoral instability.
3. Imaging
- X‑ray (AP, Lateral, Merchant, Tunnel): Fractures, alignment, DJD, osteochondral lesions.
- MRI: Gold standard for soft tissue (ligaments, menisci, cartilage, bone marrow edema).
- Ultrasound: Dynamic tendon/ligament eval, effusions, cysts (operator‑dependent).
- CT: Complex fractures, preoperative planning.
4. Advanced/Adjunctive
- Diagnostic injections (intra‑articular lidocaine) – localize pain source.
- Arthroscopy – diagnostic + therapeutic (gold standard for mechanical symptoms).
5. Specialist Referral
Orthopedic sports medicine for surgical candidates; rheumatology if inflammatory etiology suspected.
Accurate diagnosis drives targeted rehab vs. surgical decision‑making.
