Which statement best describes a grade 3 ligamentous injury?

• A. Complete tear
• B. On MRI there is complete disruption of ligament
• C. Little or no instability
• D. Extreme instability

Answer: (D)

When a ligament is graded, the level reflects how much it’s torn and how unstable the joint becomes. A grade 3 ligamentous injury means a complete rupture with gross instability. Clinically, you’d expect to find marked laxity on stress testing with a poor or absent endpoint, indicating the joint is highly unstable. Imaging such as MRI can show a complete disruption, but the grade is determined by the degree of instability rather than imaging alone. So while a full tear fits with grade 3, the emphasis is on the extreme instability that results, distinguishing it from milder grades that have little to no instability or only partial tearing.