Treatment of checkrein deformity of the hallux

Patients and Methods

We treated 11 patients with a checkrein deformity who underwent surgery between 2002 and 2006. There were six men and five women with a mean age of 36 years (19 to 60). Initially, six patients had sustained a fracture of the distal tibia and fibula, one a midshaft fracture of the tibia and fibula, one a trimalleolar fracture, one a bimalleolar fracture, one a pilon fracture and one a severe soft-tissue injury without fracture. Treatment was by intramedullary nailing in four patients, fixation with a plate in two, external fixation in one, both external fixation and fixation with a plate in one, both intramedullary nailing and fixation with a plate in two and one was managed conservatively. The mean interval between injury and the development of the deformity was 3.5 months (2 to 7). Examination revealed a typical checkrein deformity, as when the ankle was dorsiflexed the interphalangeal joint of the hallux flexed sharply; on plantar flexion of the ankle, the interphalangeal joint extended completely. Five patients also had similar deformities on the second and third toes and in one the first and second toes were affected.

Results

The mean follow-up was 20.4 months (8 to 43). There was no recurrence of the deformity in the six patients who had lengthening by Z-plasty at the midfoot. Of the five patients who had a release of adhesions and lengthening by Z-plasty above the ankle, two showed partial and one a complete recurrence of the deformity. The two patients with partial recurrence showed gradual improvement and did not wish to have a further operation. The one with a complete recurrence had a further lengthening by Z-plasty on the medial side of the midfoot which resulted in complete resolution (Fig. 1).

Fig. 1a, Fig. 1b, Fig. 1c, Fig. 1d

A 60-year-old woman with a checkrein deformity of the hallux, a) pre-operative radiograph showing a segmental fracture of the tibia and fibula, b) post-operative radiograph taken 22 months after the initial operation, c) the deformity recurred after release of adhesions and Z-plasty lengthening above the ankle at the fracture site. The checkrein deformity became more prominent when the ankle was passively dorsiflexed and d) correction after a second Z-plasty lengthening of the flexor hallucis longus tendon at the midfoot.

In one of the patients who had a lengthening of FHL above the ankle the tendon was not adherent to the fracture site but the involved muscle seemed to be ischaemic, suggesting a subclinical compartment syndrome.

At the last follow-up, nine of the 11 patients had lost some flexion of the interphalangeal joint, but none had loss of function. The power of flexion at the metatarsophalangeal joint was normal and the ability to raise the heel was intact.

Discussion

The checkrein deformity is a dynamic flexion deformity of the tendon of FHL and usually occurs after fracture of the tibia. When the ankle is passively dorsiflexed the flexion deformity of the interphalangeal joint becomes more prominent. Because the FHL tendon has some interconnection to the tendons of FDL, deformities of the lesser toes are sometimes seen.

Since Clawson⁵ first described claw toes following fractures of the tibia in 1974, checkrein deformity has been observed in other circumstances.⁶ Carr¹ observed entrapment of the tendon of FHL after fractures of the calcaneum, and computerised tomography has demonstrated entrapment of the tendon in fracture fragments. Leitschuh et al³ noted a flexion deformity of the hallux secondary to entrapment of the tendon of FHL after a fracture of the fibula. The tendon was found to be adherent at the site of the healed fracture.³

The muscle bulk of the FHL is bigger than that of the FDL behind the distal tibia which may be one of the reasons that the FHL is involved more commonly.

Most of our patients sustained fractures of both the distal tibia and fibula. Fracture of the tibial shaft or the distal fibula may produce scarring of the FHL rather than more distant muscle tendon units. A typical checkrein deformity has been described after a concomitant fracture of the distal fibula.^3,6,7 Encouragment of early movement of the toes after injury is important especially with an associated fracture of the distal fibula.

The surgical management of checkrein deformity has included release of adhesions at the fracture site and lengthening of the FHL.⁴ Sanhudo and Lompa⁷ suggested that lengthening of the tendon at the level of the midfoot is better than at a site posterior to the ankle. Feeney et al² stated that lengthening of the FHL alone is sufficient to treat concomitant check-rein deformity of the lesser toes because there are tendinous interconnections between the FHL and the FDL.

We prefer to carry out lengthening of the tendon of FHL by Z-plasty in the foot in preference to above the ankle as the surgical fields are relatively simple and are free of scar tissue. There is, therefore, less chance of recurrence of adhesions. In addition, separate lengthening of the FHL and FDL is sometimes needed, and operation in the foot allows division of the tendon interconnection between FHL and FDL. Meanwhile, operation at the site of fracture requires a large incision with dissection of neurovascular structures.

In summary, we found that lengthening of the tendon of FHL by Z-plasty in the foot provided relatively good clinical results and appeared to offer the best surgical treatment for checkrein deformity.