A Clinical Approach to Diagnosing Trigger Wrist

Abstract

Background

Trigger wrist is a relatively unusual condition, produced by wrist or finger motion. The various causes of trigger wrist can originate from flexor tendon, extensor tendon, bones, or tumour. A proper clinical approach is required to diagnose and manage patients with trigger wrist.

Methods

A keyword search was performed across Google Scholar and PubMed. Articles describing trigger wrist conditions were analysed. Based on the information obtain from the articles, the clinical manifestations and approach to diagnosing the cause of trigger wrist is discussed.

Results

A detailed history alone may lead to a reasonably accurate diagnosis. Patients can present with trigger wrist occurring during movement of the fingers or with wrist movements. Presence of tenderness around A1 pulley suggest trigger finger. Absence of tenderness over the A1 pulley may suggest trigger wrist. The wrist should be examined for any swelling or malunion around the wrist joint. Palpate for any bony prominence, clicking, or crepitus with the movement of the wrist. Examination for the presence of carpal tunnel syndrome should be performed. A simple radiograph of the wrist joint is needed to see any possible bony pathology such as malunion, instability or arthritis of the carpal bone. For soft tissue assessment ultrasound would be a good choice and can be done during finger or wrist movement. MRI is useful for further assessment of space occupying lesion within the carpal tunnel and is useful for surgical planning. Nerve conduction study is indicated for patients with median nerve compression symptoms. During the initial stage, the patient should be advised for activity modification to reduce the wrist and finger movements. Surgical treatment will depend on the causative factor. Surgery done under local anaesthesia has the advantage of reconfirming with the patient, resolution of triggering during surgery by asking the patient to actively move the fingers or wrist.

Conclusions

Trigger wrist is a relatively rare condition compared with trigger finger, which is the most common disorder of the hand. To avoid inadequate and ineffective treatment of patients with trigger wrist, careful examination and proper diagnosis are vital.

Introduction

One of the common causes of a painful clicking finger is trigger finger [1]. This is a common condition often seen at the clinic. While it may seem to be a simple problem, one has to be careful before any surgical intervention not to miss triggering occurring due to pathology at the wrist.

Trigger wrist or snapping wrist are two commonly used names that describe a pathology at the wrist that can cause painful clicking or snapping wrist on either wrist or even fingers movement [2]. This will mimic the presentation of trigger finger. The definition of trigger wrist is still controversial. Historically trigger wrist had been first reported by Marti et al. and Eibel et al. and these include cases in which movement of the wrist or fingers leads to triggering of the wrist [3, 4]. However, in 1986, Desai et al. suggested the term trigger wrist should only be applied when the triggering occurred in relation to the wrist movement and not the fingers [5, 6]. This is considered as “true trigger wrist”. In most of the trigger wrist cases, it was associated with finger movement, not wrist movement. This group of presentation is more accurately described as “trigger finger at the wrist” [7–9]. Both groups, the true trigger wrist and the trigger fingers at the wrist will be combined as trigger wrist in this discussion. The differences are the causative pathology and its location. Some of these patients also may present with carpal tunnel syndrome [10]. This is due to the mass effect within the carpal tunnel that compresses the median nerve [11]. This need to be addressed during carpal tunnel release.

As trigger wrist is an uncommon presentation compared to trigger finger, trigger wrist might be missed and to some extent, patients may be advised to undergo unnecessary medical procedures such as steroid injection and even unnecessary surgical procedures such as A1 pulley release [12]. A detailed history and complete physical examination are mandatory to decide on a further plan of action especially in the atypical presentation of trigger finger or trigger finger in association with carpal tunnel syndrome. Inappropriate management will lead to worsening of symptoms such as severe tenosynovitis, flexor tendon adhesion, or advanced carpal tunnel syndrome with thenar muscle atrophy which requires more extensive exploration or reconstructive surgery [12].

Etiology

In trigger wrist, the pathology may originate volar structures which include flexor tendons, dorsal structures which include extensor tendons and carpal bone. Suematsu et al. have classified the causes of trigger wrist arising from the volar structures. He recommended classifying the trigger wrist according to its flexor tendon pathology [13]. In Type A Suematsu classification of trigger wrist, several causative factors had been identified. Mostly is a benign tumor, of the tendon, synovial tissue, and nerve sheath namely ganglion, fibroma, lipoma, fibro lipoma, angiolipofibroma, leiomyoma, tenosynovitis and pigmented villonodular synovitis (PVNS) [2, 4, 11, 14–20]. For Suematsu Type B, it is due to anomalous muscle belly of flexor digitorum superficialis or profundus that encroaching the carpal tunnel from proximal [1, 2, 8]. The anomalous muscle belly of the lumbrical muscle which originated from flexor digitorum profundus is located within the palm, will encroach the carpal tunnel from the distal aspect [21]. In Type C there is a combination of both pathologies, for example, anomalous muscle belly of the lumbrical muscle with tenosynovitis and anomalous muscle belly of flexor digitorum superficialis with fibroma [15] (Table 1).

Table 1.

Classification of trigger wrist

I. Classification based on causative movement

a. Finger movement (Ogino)

b. Wrist movement (MacDonald)

II. Classification based on flexor tendon pathology (Suematsu)

Type A-triggering due to tumors of the flexor tendon

Type B-triggering due to anomalous muscle belly

Type C-triggering due to combination of both tumor and anomalous muscle belly

The location of the pathology is important as it may present differentially. In a pathology beneath the flexor retinacular, the patient may present earlier with symptoms associated with carpal tunnel syndrome. In this group of patients, the triggering symptoms may be absent or even minimal in cases where carpal tunnel release had been done earlier [2, 10]. Without proper examination and assessment of the primary pathology, the mass remains inside and progressively increases in size resulting in wrist swelling or the triggering over the wrist [22]. Various primary pathology had been reported located beneath the flexor retinacular such as ganglion, and flexor tendon synovitis [2, 11, 18]. Formation of cyst and tenosynovitis can also occur in patients with repetitive flexion and extension of wrist or fingers such as in musician for example in drummers [9]. If the pathology is located proximal to the transverse carpal ligament, symptoms will occur during finger or wrist extension as it will move distally and filled the carpal tunnel causing the triggering and nerve compression [8, 12, 14, 16]. The examples lipoma, ganglion and anomalous muscle belly of flexor digitorum superficialis. On the other, hand if the pathology is located distal to the transverse carpal ligament, the symptoms will occur on flexion of the fingers or wrist [4, 15, 22, 23]. This is because it follows the tendon retracted proximally on muscle contraction. The anomalous muscle belly of lumbrical, lipoma, giant cell tumor and schwannoma are among the common causes for the distal lesion. Shimizu et al. reported a case of carpal tunnel syndrome caused by hypertrophied lumbrical muscle with flexor tenosynovitis due to overuse from heavy labour [21]. Shimizu et al. has proposed the association of trigger wrist, carpal tunnel syndrome, and anomaly of lumbrical muscle which characterized by mostly patients in middle-aged males, single-sided involvement, worsening of symptoms on finger flexion, positive fist test result, triggering at wrist and resistance to conservative management [21].

In a true trigger wrist, the pathology is related to the extensor compartment and intracarpal pathology [6]. Lemon et al. reported a case presented with a true trigger wrist due to a nodule in the extensor carpi radialis longus tendon. The triggering occurred each time the nodule passed through the second compartment. The triggering was treated by reduction tenoplasty and releasing the second compartment [24]. Then, Kood et al. reported a synovial mass around the extensor carpi radialis brevis and extensor pollicis longs tendon at the level of extensor retinacular [25]. Series of patients presented with true trigger wrist due to recurrent subluxation of extensor carpi ulnas tendon also had been reported by Eckhart et al. [26]. Few other diagnoses need to be excluded when patents presented with clicking or painful wrist, namely De Quervain ‘s tenosynovitis, intersection syndrome, EPL tenosynovitis, fourth compartment tenosynovitis, fifth compartment tenosynovitis, ECU tenosynovitis, and FCR tendinitis.

Incidence

Trigger wrist is an uncommon condition and it is also under reported [22]. This could be since the patient may have been diagnosed with trigger finger or carpal tunnel syndrome and may have undergone surgery [12]. No studies are reporting the incidence or even prevalence of trigger wrist. Inglis et al. had reported 2 out of patients with carpal tunnel syndrome with space-occupying lesions [27]. In Suematsu’s series of 18 patients with trigger wrist,14 of them had carpal tunnel syndrome [13] (Table 2).

Table 2.

Showing the various causes of triggering at the wrist

1. Flexor tendons	3. Bones
Giant cell tumour of the tendon	Snapping lunate syndrome
Flexor tenosynovitis	Scapholunate subluxation
Flexor carpi radialis tendinitis
Anomalous muscle belly of lumbrical
Anomalous muscle belly of flexor digitorum superficialis
Intramuscular lipoma	4. Soft tissue structures
	Ganglion
2. Extensor tendons	Lipoma in palm, carpal tunnel and forearm
Acute partial rupture of ECRB	Adhesion
ECRL nodule	Schwannoma
De Quervain stenosing tenosynovitis	Fibromatosis
Intersection syndrome	Neurofibroma
EPL tenosynovitis	Leiomyoma
Fourth compartment tenosynovitis (EDC)	Desmoid tumor
Fifth compartment tenosynovitis (EDM)	Pigmented Villonodular Synovitis (PVNS)
ECU tenosynovitis/subluxation	Fibrous histiocytoma
	Extensor retinacular thickening

Ogino et al. described trigger wrist induced by finger movement [10]. MacDonald et al. reported a patient with grade 3 trigger finger of the index finger which released by twisting motion of the wrist [18]. There was no pain or mass over the A1 pulley. Suematsu [13] proposed a classification system that was based upon flexor tendon sheath pathologies. In their review, 16 of the 18 cases were associated with carpal tunnel syndrome. He described type A where the triggering occurred due to tumors of the flexor tendon, type B due to the anomalous muscle belly, and type C a combination of both tumor and anomalous muscle belly [13].

History

A detailed history may lead to a reasonably accurate diagnosis. The precise nature of the triggering must be obtained from the patient. The patient may describe the complaint as triggering, snapping, clicking, or catching sensation at the wrist. A click occurring while gradually extended the wrist from the position of full palmar flexion may suggest the presence of scapholunate dissociation [28]. Some may even experience pain in the palm on gripping objects [29]. When a patient presents with triggering at the wrist, it could be caused by the movement of the fingers, wrist movement, or forearm supination or pronation [10] Ask the patient if the triggering occurs with movement of the fingers. If a patient does have triggering with the movement of the fingers, ask them if they have any discomfort in the hand (to rule out discomfort around the A1 pulley) or around the wrist. If there is discomfort around the wrist, does the discomfort occur during flexion or extension of the fingers. Snapping of the middle finger with symptoms of carpal tunnel syndrome may suggest an encroachment of the tendon by a growth [14]. Patients presenting with trigger wrist occurring during movement of the fingers are more common compared to patients with trigger wrist occurring with wrist movements [7]. We need to differentiate whether it is a trigger finger, true trigger wrist, or trigger finger at the wrist. Triggering of the fingers may occur several weeks before the trigger wrist phenomenon [30]. It is difficult to differentiate between trigger wrist or finger in the absence of typical triggering or snapping around the wrist, the patient may present with discomfort or pain caused by finger movement and not occurring with wrist movement [12]. Persistent pain and decreased range of motion of the wrist may suggest entrapment of the tendon [31]. Patients may also present with symptoms of carpal tunnel syndrome. Paraesthesia may be brought about by flexion of the fingers [32].

Physical Examination

The characteristic complaints by patients with trigger wrist are triggering, snapping, clicking, or catching at the wrist. It can happen either during fingers or wrist movement and flexion or extension. This depends on the location of the mass in relation to the transverse carpal ligament.

Prominent finger triggering and correlation with a palpable nodule, triggering, and tenderness around the A1 pulley are suggestive of trigger finger [8]. The difference is point tenderness at the A1 pulley region. Ask the patient to move the fingers. Observe if one or more fingers are triggering. Palpate for tenderness or mass over the A1 pulley [8], absence may suggest trigger wrist. If there is no swelling or tenderness at the A1 pulley, palpate for any nodule or swelling at the wrist on both the dorsal and volar aspect with the movement of the fingers. This will eliminate any cause of triggering originating from the flexor or extensor tendons. If there is triggering with flexion of the fingers the mass is probably distal to the carpal tunnel. If the triggering occurs with the extension of the fingers the mass or lesion is proximal to the carpal tunnel. The location of the mass if palpable can be felt either proximal or distal to the carpal tunnel and move during the finger movements. Each of them have different provocative conditions. The transverse carpal ligament width from proximal edge to distal edge is about 1 inch (2.5 cm), however, the tendon excursion upon full flexion and extension is about 1 3/8 inches (3.34 cm) which made it go through the carpal tunnel either from distal to proximal or vice versa [4]. So, in patients with mass distal to carpal tunnel such as lipoma, fibroma, schwannoma, and anomalous muscle belly of the lumbrical the triggering will occur during flexion or even a palpable click over the wrist. If the lesion is big enough it will cause median nerve compressive symptoms during the full flexion. The patient will be more comfortable keeping the finger in extension [4, 15, 22, 23]. Contrary to the group of patients with the lesion proximal to the carpal tunnel, they are more comfortable to keep the finger in semi flexed because with the extension of fingers the lesion will migrate distally through the carpal tunnel [8, 12, 14, 16]. If there is no triggering with finger movement, look for triggering with wrist movement. Examine for any swelling at the wrist or malunion around the wrist joint. Palpate for any bony prominence, clicking, or crepitus with the movement of the wrist. Examination for the presence of carpal tunnel syndrome should be performed. In a patient presenting with symptoms of carpal tunnel syndrome of the wrist with lipoma arising from the tenosynovium of the wrist, the tests for both the Phalen test and reverse Phalen were both negative. Even the Tinel-like sign was negative. As shown in the paper by Sonoda et al. the patient’s.

numbness increased by the carpal compression test. This finding was confirmed by the nerve conduction study [14] (Tables 3, 4).

Table 3.

Showing the different excursions of the finger flexors

Tendon	Mean (mm)	Range (mm)
A. Superficialis
Extension	26	15–37
Flexion	21	6–32
B. Profundus
Extension	33	19–43
Flexion	28	15–17
C. FPL
Extension	19	10–28
Flexion	21	12–29

Table 4.

Showing the excursions of the long wrist flexors

Tendon	Excursion (mm)
FCR	12.2 ± 2.1
ECU	11.3 ± 2.1

Imaging

A simple radiograph of the wrist joint is needed to see any possible bony pathology such as malunion, instability or arthritis of the carpal bone [8, 27, 33]. For soft tissue assessment, ultrasound would be a good dynamic investigation and allows the examiner to assess the pathophysiology of the triggering as it is a dynamic problem. The dynamic assessment can be done during fingers and wrist movements. Information regarding the lesion can be elicited by ultrasound for its size, depth, margin, echogenicity, consistency, vascularity, and relationship to other structures [19].

In patients with trigger wrist, further evaluation needed either ultrasound or MRI for further assessment of space-occupying lesion within the carpal tunnel [8]. This will provide detailed information regarding the mass such as characteristics of the mass, extension, and possible origin of the mass [12]. With this information, surgical planning can be done and executed with greater success by adequate complete excision and minimized risk of recurrence [19].

Electrodiagnostic Studies

Nerve conduction study is indicated for patients with median nerve compression symptoms. A delay of distal latency more than 2 ms for sensory and more than 4 ms for the motor are suggestive of median nerve compression [22]. This can be used either as guidance for a decision of management or monitor progression pre and postoperatively.

Conservative Management

On the initial stage during workup done to find the causative pathology, the patient will be advised for activity modification to reduce the wrist and finger movements. If the pain during triggering is troublesome wrist splint is advocated and supplemented with analgesic as necessary. Patients with symptoms of carpal tunnel syndrome will need the routine conservative management before definitive surgical plan.

Surgical Treatment

This will depend on the causative factors. Preferably after radiological investigation to delineate the mass, surgery will be planned under general anesthesia [19]. However, the advantages of doing the surgery under local anesthesia can reconfirm with the patient immediately during surgery by asking the patient to actively move the fingers or wrist and showing resolved symptoms [6]. This is advisable for the patient with trigger wrist and carpal tunnel syndrome without definitive lesion detected by MRI or even CT Scan.

Carpal tunnel release is done as a surgical approach for exposing the mass and for patients presented with carpal tunnel syndrome with trigger wrist. After flexor retinacular ligament incised, an inspection of the content of the carpal tunnel to evaluate any incoming mass or muscle from the proximal or distal margin. The excision of the mass or anomalous muscle belly will be done [2].

The prognosis is good if it is done at the earlier stage of the disease. In chronic cases with irreversible pathology to the surrounding tendon and even the median nerve, the prognosis is guarded.

Conclusion

Due to it is an uncommon presentation of trigger wrist and various possible pathologies, detailed history taking, and examination is mandatory. In patients presenting with an unusual presentation of trigger finger, assessment of lesions proximal to A1 pulley is indicated. Cardinal symptoms of trigger wrist are more than two fingers triggering at the wrist with mild to moderate carpal tunnel syndrome and palpable mass or crepitus felt over the wrist. Subsequent investigations such as plain radiograph or ultrasound will guide for further detailed radiological investigation such as MRI or CT Scan to delineate the extension and origin of the lesion before definitive surgery.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical standard statement

This article does not contain any studies with human or animal subjects performed by the any of the authors.

Informed consent

For this type of study informed consent is not required.