Abstract
Trigger wrist is a relatively rare phenomenon. The pathological entities to which the term trigger wrist is applied are not well defined in the literature. We present three cases of trigger wrist as a result of flexor tendon pathology, review the literature and discuss the use of the term “trigger wrist”.
CASE REPORTS
Case 1: A 67 year-old female with rheumatoid arthritis was referred with painful limitation of wrist and finger motion. Increasing numbness in the thumb, index and middle fingers was also reported. Physical examination showed a palpable, moving mass in the palm, which produced painful triggering on passive flexion or extension of the wrist and fingers. Preoperative nerve conduction studies of the median nerve showed a distal conduction-time delay.
During carpal tunnel decompression, rheumatoid tissue was found in the palm and the median nerve was hypertrophic. There were ruptures of the superficial flexor tendons of the index, the ring and the middle finger. Adhesions around the profundus flexor tendons were responsible for the mass palpable pre-operatively. Extensive synovectomy, followed by reconstruction of the superficial flexor tendons of the index and middle finger was carried out. Histological examination confirmed chronic rheumatoid synovitis. Partial recurrence of the mass one and a half years after the operation led to progressive lack of full flexion of the fingers with slowing of motion, but without recurrence of the triggering. Sensory disturbances of the hand had disappeared at 40 month follow-up.
Case 2: A 46 year-old man presented with triggering of his left wrist during flexion and extension and inability to fully flex his ring and little finger. He had been carrying out heavy manual work during the previous few days. He was, also, complaining about a strange feeling of “electricity” along his ulnar fingers during finger motion. The hand was swollen and painful. Surgical exploration revealed rupture of the superficialis flexor tendon of the ring finger in zone 4. The proximal stump had formed a fibrotic mass adherent to the profundus flexor tendon. During finger motion, the fibrotic mass was catching on the deep transverse palmar ligament causing a triggering effect. The tendon was repaired with a palmaris longus graft and the wrist triggering was absent post-operatively.
Case 3: A 47 year-old female presented with painless triggering of the left wrist. The triggering was evident during flexion and extension movements of the wrist and fingers. The patient also had night pain with loss of sensation of the three radial fingers. A palpable mass could be identified just distal to the transverse palmar ligament. Surgical exploration revealed a nodular mass of size 2.5 ×1 cm, which was adherent to the index superficialis tendon and which was blocking normal tendon movement. The nodule was excised and the triggering disappeared, along with the sensory disturbances. Laboratory examination revealed chronic exudative synovitis.
DISCUSSION
Triggering at the wrist is relatively rarely reported, even in association with flexor tendon synovitis. Kellegren (1950) and Flatt (1968) believed that nodule formation due to flexor tendon synovitis inside the carpal tunnel is a very common occurrence, but it rarely produced the triggering phenomena. A possible explanation for this could be the early treatment of carpal tunnel syndrome symptoms before triggering occurs. Minami and Ogino (1986) suggested that many wrists with definite triggering were not reported as triggering wrists but as carpal tunnel syndrome (Dohi et al., 1972; Kojima et al., 1971; Matsuzaki and Mitsuyasu, 1971). The literature also contains trigger wrists reported under different names, e.g. “snapping wrist” (Jackson and Protas, 1981; Rupnik and Szloboda, 1991; Zachee et al., 1993) and “clicking wrist” (Weeks et al., 1979). Since the first reports of trigger wrist by Marti (1960) and Eibel (1961), the term “trigger wrist” has been used to include cases in which either passive or active movement of the wrist or the fingers caused triggering of the wrist. After reviewing the literature, Suematsu (1985) classified the aetiology of wrist triggering into three types, all of which involved flexor tendon pathology (Table 1). Our cases are typical examples of the flexor tendon pathologies included in Suematsu’s classification and are similar to those described by Davalbhakta and Bailey (1972) and Minami and Ogino (1986).
Desai et al. (1986) suggested that the term “trigger wrist” should only be used when triggering occurred, specifically, on wrist movement. However, the majority of the reported cases of wrist triggering have a clear finger involvement (Carneiro et al., 2001; Carvell et al., 1983; Dohi et al., 1972; Forstner and Schaefer, 1988; Itsubo et al., 2004; Pople, 1986; Rupnik and Szloboda, 1991). Nevertheless, there are cases of “true” wrist triggering precipitated by wrist movements only. Lemon and Engber (1985) was the first to use the term “true” trigger for a case of trigger wrist caused by a nodule in the extensor carpi radialis longus tendon. More recently, Koob and Steffens (1988) reported the same pathology causing wrist triggering. Implication of the extensor tendons in trigger wrist had been known earlier as Eckhardt and Palmer (1981) described four cases with recurrent subluxation of the extensor carpi ulnaris tendon in the sixth extensor compartment causing triggering of the wrist (Fig 1).
Jackson and Protas (1981) found it very difficult to classify their findings according to the existing literature for a “snapping” scapholunate subluxation during wrist motion and made the comment that “…no complete description of the precise abnormality encountered was found in the surgical or roentgenographic literature”.
Unfortunately, Suematsu’s classification does not reflect the pathological aspects of this phenomenon accurately. There are also, clearly, extensor tendon compartment and intracarpal (Jackson and Protas, 1981; Zachee et al., 1993) pathologies which can cause wrist triggering. These should, at least, be included in a more comprehensive classification. It is, also, debatable whether all of the cases discussed should still be called “trigger wrist”, or whether only those cases with triggering only on wrist movement should be so named and those within Suematsu’s classification described as “pseudo-trigger wrist”.