What is the AAOS normative end feel for knee extension?

• A. Hard
• B. Soft
• C. Firm
• D. Empty

Answer: (C)

End feel is the characteristic sensation you feel right at the end of a passive range of motion. For the knee when you extend it, the normal end feel is firm. This comes from the tension of the posterior knee structures as you approach full extension—the posterior capsule, ligaments, and surrounding soft tissues become taut and resist further movement with a stretch-like resistance. It’s not a hard bone-on-bone stop, and it isn’t a soft tissue compression or an absence of feel due to pain. A soft end feel would be more typical with knee flexion when the thigh and calf soften contact, and an empty end feel would indicate pain limiting the motion. So, the normative end feel for knee extension is firm.