De Quervain's Part Two:
Why It Happens and How to Stop It Before It Starts

De Quervain's is a load problem. The two tendons running through the first dorsal compartment of the wrist are under significant tension any time the thumb is abducted — moved away from the hand — especially when that movement is combined with ulnar deviation of the wrist, bending toward the little finger side. That combined position is exactly what happens when you lift a baby by sliding your hands under their arms with thumbs extended, when you hold a phone and scroll, when you grip a fly rod and cast, or when you perform certain repetitive manual tasks for hours at a time. I developed a mild case myself years ago. I know the mechanism from both sides of the examination table.

The prevention principles

Prevention comes down to two principles. The first is load management: breaking up repetitive thumb abduction tasks, modifying grip mechanics where possible, and building in recovery time before cumulative irritation crosses the threshold into inflammation. For new parents this is genuinely difficult — the frequency of infant lifting is dictated by the infant, not the parent — but small adjustments like consciously keeping the thumb adducted and close to the hand during lifts rather than extended outward can meaningfully reduce the tendon load.

The second principle is early recognition. De Quervain's responds very well to treatment in the first few weeks. The Finkelstein test we covered in Issue 4 is something you can perform on yourself anytime you notice soreness developing on the thumb side of the wrist. A positive result at that early stage, combined with activity modification and a brief period of splinting, can stop the progression before it becomes a chronic problem requiring injection or surgery. The window is real, and it is worth acting in it.

Who is most at risk

New parents top the list — the combination of repetitive infant lifting with thumbs extended and sleep deprivation that blunts pain awareness is a reliable formula for De Quervain's in the first six months postpartum. Fly fishermen develop it from extended casting sessions with an extended thumb grip. Gamers develop it from sustained controller use with the thumb in a partially abducted position for hours. What all of these have in common is cumulative load without adequate recovery — not a single traumatic event, but a threshold crossed gradually over days or weeks.

If you fall into one of these categories and notice soreness on the thumb side of your wrist, take it seriously early. The treatment trajectory for De Quervain's caught in the first two to four weeks is dramatically better than the trajectory for De Quervain's that has been present for three months. Early means splint, modify, consider a single cortisone injection. Late means longer splinting, more injections, and potentially a surgical release that could have been avoided entirely.