The results of Zone 2 flexor tendon lacerations in children are variable, with good to excellent results reported between 53 to 80%. This study examined flexor tendon lacerations in children using a uniform method. The cohort consisted of twelve children over a 10-year span. The average age was 2 years and 10 months, with a range from 1 year and 2 months to 5 years and 10 months. Time from injury ranged from 0 to 42 days, with an average of 23 days. The flexor digitorum superficialis and the flexor digitorum profundus were lacerated in six patients, the flexor digitorum profundus and half of the flexor digitorum superficialis tendon were lacerated in three, and an isolated FDP tendon laceration occurred in three. All tendons were repaired with a two-strand core suture and a running or interrupted epitendinous suture. Associated digital nerve injuries were repaired using microsurgical techniques. No arterial repairs were required. Following surgery, the arms were immobilized in a long-arm cast, with the wrist in slight extension, the metacarpophalangeal joints and proximal interphalangeal joints in 90° of flexion, and the distal interphalangeal joints in 60° of flexion. The non-injured digits were similarly immobilized, but the interphalangeal joints were placed in neutral. Immobilization ranged from 3 to 4 weeks. No splint was used following cast immobilization. The follow-up period averaged 8 years and 2 months. The Strickland formula for total active motion was utilized, whereby the extensor lag is subtracted from the sum of interphalangeal joint flexion. The length of the injured finger was measured to evaluate physeal growth.
This study showed remarkable results following flexor tendon repair in children. Total active motion of the proximal and distal interphalangeal joints averaged 155°. The total active motion percentage averaged 89%. No ruptures occurred, and one patient required tenolysis 9 months after tendon repair. Two patients showed considerable growth disturbance of the affected finger. As reported previously, a delay in diagnosis is common and this complicates tendon repair. Nonetheless, this uniform approach, consisting of core suture, epitendinous repair, and strict immobilization resulted in a 100% incidence of excellent or good results after primary repair. This period of strict immobilization would not be applicable in the adult population, but appears to be effective in children younger than 6 years of age. The reason behind the two patients with growth disturbance remains questionable. Both of these patients had the worst total active motion, which may be a factor that contributes to overall growth of the digit.
J Pediatric Orthopaedics