De Quervain Tendinopathy

de Quervain tendinopathy or de Quervain stenosing tenosynovitis is a common overuse disorder of the wrist affecting the first dorsal compartment at the radial styloid process.
==Aetiopathogenesis==
The disease affects the first dorsal compartment which contains the extensor pollicis brevis (EPB) and abductor pollicis longus (APL) tendons. The APL and EPB allow thumb radial abduction. The tendons are secured against the radial styloid by the extensor retinaculum, creating a fibro-osseous tunnel about 1cm long. 
There are anatomical variations, for example these tendons can be contained within a single sheath (common form) or there can be a septum that divides the the APL and EPB (variant), with the variant form having higher rates of ending up with surgical management.
The APL can have various numbers of slips. The EPB, which is usually a single tendon slip, can slip into various subcompartments at the radial styloid. The most common number of tendon slips is two for APL and one for EPB. 
The aetiology is not well understood but is thought to be due to friction of the EPL and APB against the zone 7 pulley of the extensor compartment. There is controversy around the role of inflammation in the disease. 
The classic argument is that there is an initial tendinopathy followed by a reactive thickening. There is a commonly quoted classic study by Clarke et al where histopathologic analysis showed the disease to be noninflammatory, with thickening of the tendons and the tunnel with myxoid degeneration. Yet there are other studies in particular one very important one by Kuo and colleagues that used modern immunohistochemical staining that showed that there is indeed an inflammatory response. They also found that the expression of inflammatory markers correlated with the severity of symptoms. 
Inflammation may help explain the predilection of the disease for women. Some authors counter that any inflammation is simply a superimposed phenomenon on tendon degeneration. See Fakoya and colleagues for a detailed discussion and literature review on the topic. 
There are some arguments against the overuse theory. One argument is why is there a very high prevalence in women. Men are over-represented in jobs involving manual labour such as in assembly lines, and so you would expect it to be more common in men. Another argument is that you would expect it to be more common in the dominant hand, yet it is not. It may be that work related factors are simply a catalyst. 
== Epidemiology and Risk Factors ==
It predominantly effects women with incidence rates of 2.8 per 1000 in women vs 0.6 per 1000 in men. Age greater than 40 is a risk factor. It is particularly common in the 4-6 weeks postpartum period in young women. It also commonly affects early childcare workers. Some of the reported culprit activities include typing, knitting, gardening, golf, and tennis. Those with Rheumatoid Arthritis and diabetes may be at higher risk.
It is generally related to overuse especially with work that involves pronation and supination (e.g. screwdriving). However it can occasionally result after a direct blow.
==Clinical Features==
=== History ===
Patients report pain over the radial aspect of the distal radius. They may also report swelling. The pain is exacerbated by ulnar deviation, a strong grasp combined with flexion and radial deviation, or by firm opposition of the thumb and index finger. The dominant hand is not more likely to be affected than the non-dominant hand, and symptoms can be bilateral. 
=== Examination ===
There is tenderness and swelling over the first dorsal compartment at the radial styloid. Patients with severe synovitis can have allodynia in the author's experience.
There are several special tests, with Finkelstein and Eichoff being the most commonly performed. The Finkelstein and Eichoff tests are commonly confused in the literature.
Finkelstein: One hand of the examiner holds the thumb of the patient, while the examiners other hand holds the forearm on teh ulnar side in a position of neutral pro-supination. The examination places firm longitudinal traction on the patient's thumb, in the direction of slight ulnar deviation. A positive test is where the index pain is reproduced.
Eichoff: The patient opposes their thumb into the palm and flexes their fingers over the thumb. The examiner applies passive ulnar deviation to the patient's wrist while their other hand holds their forearm on the ulnar side. A positive test is where the index pain is reproduced. This test has a high rate of false positive.s The positive LR is 1.04, and negative LR is 0.75.
WHAT test: This stands for wrist hyperflexion and abduction of the thumb. It was designed to more specifically apply force to the first dorsal compartment and be an active rather than passive test. The patient is asked to flex their wrist to the limit of pain while keeping their thumb in full extension and abduction. The examiner applies a gradually increasing resistance to the patient abducting their thumb. A positive test is where the index pain is reproduced. The positive LR is 1.39, and negative LR is 0.04. This test has a superior ability to correctly diagnosed the absence of de Quervain's.
==Diagnosis==
Based on characteristic history of atraumatic radial sided wrist pain with tenderness and enlargement of the first dorsal compartment over the radial styloid, and pain at the radial styloid with active or passive stretch of the tendons over the radial styloid in thumb flexion. 
==Differential Diagnoses==
==Imaging==
* Xray may help evaluate other causes such as OA of the 1st CMC joint. However in de Quervains, plain films are normal.
* Ultrasound may show a thickened extensor retinaculum with hypervascularity. There may be thickening of the APL and APB tendons, however the EPB may be thinned due to stenosis from a thickened extensor retinaculum. Ultrasound is very helpful with identifying septation especially if injection or surgery is being considered.
==Management==
The condition is normally self-limited. It generally resolves after a year, and doesn't usually recur.
NSAIDs
Activity Modification
Splinting
Forearm-based thumb spica splint with the interphalangeal joint free. There is no difference between full-time and as required splinting in an RCT addressing this very question. It isn't clear whether splinting necessarily changes the course of the disease, but it may allow patient's to continue their normal daily activities.
Steroid Injection
See page on De Quervain Injection. There is moderate evidence for doing an ultrasound guided steroid injection as a first line therapy over splinting alone. Cure rates are between 62-100%. Failure to respond is associated with the presence of a septum. This is one strong argument for using ultrasound guidance. 
If pain recurs after two weeks a second injection can be performed. Most patients respond after either the first or second injection. If the pain recurs again then other options should be explored, such as watching and waiting as most recover on their own after one year. However 
Surgery
Most cases resolve without surgery. There are no placebo-controlled trials. It involves releasing the the first dorsal compartment. Complications included an erythematous, raised, and tender incision area for 6 to 12 months, injury of the superficial radial sensory nerve, failure to improve symptoms, and inability to use the wrist for a few weeks postoperatively.
==References==
Category:Hand and Wrist Conditions
Category:Tendinopathies