About 10 percent of the time, after [a] patient has recovered … pain persists. It persists for months and oftentimes for years, and when that happens, it is its own disease.

Krane is describing the clinical transition from acute pain (a symptom tied to injury or illness) to chronic pain, which can outlast tissue healing and become a self-sustaining condition. The “10 percent” figure underscores that persistent pain is not a rare anomaly but a predictable outcome for a significant minority of patients. Calling it “its own disease” reflects a modern pain-medicine view: long-term pain involves changes in the nervous system (sensitization, altered signaling, and psychosocial feedback loops) that require targeted treatment rather than simply continued investigation for an original injury. The quote argues for recognizing chronic pain as a distinct medical problem with its own mechanisms, risks, and care pathways.