Complex trigger wrist associated with carpal tunnel syndrome: a case report

Trigger wrist is a rare pathology that can lead to loss of wrist function [1, 2, 4]. It is defined as an occurrence of triggering or painful clicking at the wrist joint level, induced by wrist or finger movement [2, 4]. Such symptoms are caused by temporary compression of the nerves in the carpal tunnel or extensor retinaculum area by tumor or adhesions [4]. The most frequent reason for this condition is fibroma of the flexor tendons or tendon sheath [1, 4]. We report a clinical case of a patient with complex trigger wrist caused by fibroma of the flexor tendon sheath. We believe this case to be complex and unique because of the difficult differential diagnosis between trigger finger and trigger wrist and unclear results of clinical examination. We also present a literature review and demonstrate the classifications used for this pathology.

A 45-year-old white slavic male presented with 4-year history of “clicking” of the right wrist. For the last 2 years, pain at the right wrist joint level and fourth finger flexion failure had also occurred. All the symptoms were induced by wrist and fourth finger flexion and extension. Recently, the patient had noted weakening of the right wrist. Examination did not reveal any visible or palpable pathology at the wrist level. Weakening of the right wrist was noted while the patient was grabbing the examiners’ hand. Neurological examination revealed reduced sensitivity (pain) via the median nerve area at the right wrist. Triggering at the right wrist was noted during flexion and extension of the radiocarpal joint. Despite the obvious presence of carpal tunnel syndrome, Tinel’s sign was not present. MRI of the right wrist was performed: no pathological masses were seen inside the carpal tunnel. The compression of the right median nerve was confirmed by electroneuromyography. Carpal tunnel release was performed. An oval-shaped fibroma was identified in the carpal tunnel (Fig. 1a). The tumor was attached to the flexor superficialis tendon sheath and was moving through the carpal tunnel via fourth finger and wrist flexion and extension. The fibroma was excised, and the wound was closed (Fig. 1b). A morphological study was performed (Fig. 2a). Immunohistochemical analysis was performed for differential diagnosis with peripheral nerve tumors (Fig. 2b). The tumor was composed of cells with a myoid phenotype (Fig. 2c). The postoperative protocol included positioning the hand in a resting splint, regular wound dressings, and antibiotics for 3 days. All fingers were left free for regular active finger exercises. The patient was discharged after 3 days of the postoperative period. Sutures were removed after 2 weeks after surgery. The patient was followed up at 2, 4, and 6 weeks after the operation. During the last follow-up visit, there were no signs of trigger wrist or carpal tunnel syndrome.

Several classifications can be found in literature. Historically, the first classification of trigger wrist was offered by Suematsu et al. (Table 1) [1]. It is based on etiological factors. Various authors report that this classification is not informative enough [2, 3, 6, 7]. Al-Qattan et al. (Table 2) [3] offered an extended classification. The reported case is classified as type A, which is the most common type of trigger wrist [1‐3].

Differential diagnosis of trigger wrist and trigger finger is important [4, 5]. Trigger finger, also known as stenosing tenosynovitis, is usually caused by a size mismatch between the first annular pulley (A-1) and the flexor tendon [5]. More rarely it can be caused by a pathology inside the carpal tunnel [9]. Unlike trigger wrist, trigger finger is a common disease [5‐8]. The symptoms of trigger finger include clicking, snatching, or triggering in the finger area, induced by the finger movement [4, 5, 8]. Clinically, while palpating the A-1 area, pain can be present [5]. In the reported case, the patient expressed no pain around the A-1 area, so the presence of stenosing tenosynovitis was unlikely. However, if trigger finger caused by stenosing tenosynovitis is mistaken for trigger wrist, then this can lead to an unnecessary release of the carpal tunnel, which introduces the risk of damaging its structures and development of adhesions [4, 8]. The adhesions within the carpal tunnel can be an etiology of trigger wrist type E by Al-Qattan et al. [3]. Another reason for the development of the adhesions is rheumatoid arthritis [6, 7]. Giannikas et al. [6] and Minetti et al. [7] reported several cases of trigger wrist induced by adhesions of flexor tendons inside the carpal tunnel, caused by rheumatoid arthritis.

Park et al. [4] also reported cases of trigger wrist with difficult diagnosis: clinically the condition was referred to as trigger finger, although there was a palpable mass inside the carpal tunnel and clicking occurred around the wrist joint area. It is stated that augmented CT scan was not informative enough [4]. The diagnosis of trigger wrist was finally stated when the carpal tunnel was revised and an anomalous muscle belly was found [4].

In our patient, carpal tunnel syndrome was present, but Tinel’s sign was not revealed—this phenomenon was also demonstrated by Macdonald et al. [10]. The authors present a trigger finger case caused by a ganglion, located inside the carpal tunnel, with associated carpal tunnel syndrome and negative Tinel’s sign [10].

Similar cases demonstrating that trigger finger is not always caused by A-1 pulley pathology can be found: Parmaksızoğlu et al. [9] reported three patients with trigger finger at the carpal tunnel level with the A-1 pulley intact. All of them were caused by a tumor inside the carpal tunnel [9].

In our patient, clicking and pain were located mainly around the wrist joint area, which was in favor of trigger wrist diagnosis. However, the fact of the fourth finger “locking” and other symptoms induced not only by wrist movement but also by fourth finger movement were the main factors to consider this case complex in terms of differential diagnosis between trigger finger and trigger wrist. Furthermore, the fibroma in the reported patient was not palpable and was not seen clearly on the MRI scan. We state that, in a case where clinical symptoms of both trigger wrist and trigger finger are present, except painful palpation of the A-1 pulley region, the diagnosis should be considered as trigger wrist. Pain around the A-1 area makes the diagnosis of trigger wrist less possible. Further research is needed.

A case of trigger wrist with a difficult differential diagnosis is presented. Despite the complexity of the case, a correct surgical procedure was performed. All the symptoms regressed, and the patient was satisfied with the treatment.