De Quervain’s tenosynovitis (DQT) is a common condition that causes pain and swelling on the thumb side of the wrist, also known as the radial side. This overuse injury involves irritation and thickening of the sheath surrounding two specific tendons that control thumb movement. Conservative management, which focuses on reducing inflammation and resting the affected tendons, is the primary initial treatment approach. Splinting is a mainstay of this treatment, as it mechanically restricts painful movements to allow the tendons to heal.
The Specific Immobilization Requirement
The pain in DQT arises from the friction and constriction of the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) tendons as they pass through a narrow tunnel on the wrist. These two tendons are responsible for moving the thumb away from the palm (abduction) and straightening the thumb joint (extension). To achieve necessary rest, the splint must stabilize the thumb at the carpometacarpal (CMC) and metacarpophalangeal (MCP) joints. Restricting movement at these joints places the tendons in a non-stressful position, easing friction and allowing swelling to subside. The splint design also often aims to limit wrist movement toward the small finger side, known as ulnar deviation, as this motion significantly aggravates the inflamed tendons.
Classifying Splint Types for De Quervain’s
The most frequently prescribed device for DQT is the thumb spica splint, categorized by the extent of immobilization it provides. The two main types are the Short Thumb Spica Splint and the Long Thumb Spica Splint, both incorporating a rigid or semi-rigid stay along the radial side of the forearm. The Short Thumb Spica Splint immobilizes the thumb’s CMC and MCP joints while allowing full wrist motion, often using flexible materials like neoprene. Conversely, the Long Thumb Spica Splint is more restrictive, extending further up the forearm to immobilize both the thumb and the wrist joint itself. These long splints are frequently custom-made from rigid thermoplastic materials, providing more complete rest by preventing wrist movements that can stress the tendons.
Criteria for Selecting the Best Splint
The “best” splint for DQT is individualized, depending on symptom severity and lifestyle demands. For severe, constant pain aggravated by minimal movement, the Long Thumb Spica Splint is preferred, as full immobilization of the wrist and thumb provides the most effective rest. However, the rigidity and bulk of a long splint can interfere with daily tasks, potentially leading to poor adherence. For patients with moderate pain or those requiring wrist flexibility for work, the Short Thumb Spica Splint is a more functional alternative, provided it effectively restricts thumb movement.
Fit and Adherence
The material and fit are crucial for adherence; custom-molded thermoplastic splints offer optimal positioning and precise contouring. Pre-fabricated splints must be carefully sized to ensure a snug fit without causing pressure points, as a well-fitting splint is more likely to be worn consistently.
Optimizing Use and Adjunct Treatments
Consistent use of the chosen thumb spica splint is paramount for successful conservative treatment, especially during the initial acute phase. Providers often recommend continuous wear for two to four weeks, removing it only for hygiene, before reducing use to nighttime or during aggravating activities. Splinting is most effective when combined with other supportive therapies. Anti-inflammatory medications (NSAIDs) can be used concurrently to manage pain and reduce systemic inflammation, along with regular application of ice packs to decrease localized swelling. If symptoms are severe or do not improve with splinting alone, a corticosteroid injection directly into the tendon sheath may be administered.