Pediatric flexor tendon injuries: A 10-year outcome analysis.

Background: Primary flexor tendon repair was first introduced in the 1960s. Since then, major advances in the understanding of flexor tendon anatomy and biology have led to improved outcomes following repair. Relative to the adult population, sparse knowledge exists as to which operative and postoperative treatments are most successful in children. This is due, in part, to the rarity of pediatric tendon lacerations compared with the adult population, but also related to challenges when working with smaller anatomy and the decreased compliance in children with respect to rehabilitation protocols. Published reports indicate that the incidence of 'good' flexor tendon repair outcomes is as low as 53%.

Objective: To determine the injury pattern and demographics of pediatric flexor tendon injuries involving zones I, II and III over the past decade, and to report results and identify treatment paradigms that are associated with optimal outcomes.

Methods: A retrospective chart review of all flexor tendon injuries involving zones I, II and III between April 2001 and December 2010 was performed. Parameters reviewed included demographics, injury mechanism, repair technique, outcomes and complications.

Results: A total of 47 patients with a median age of eight years experienced 100 tendon injuries. The most common cause of injury was glass (n=22), with the most common digit injured being the small finger (n=30). Tendon injuries included the following: flexor digitorum superficialis (n=46); flexor digitorum profundus (n=45), flexor pollicis longus (n=8); and adductor pollicis longus (n=1). Zone III had the highest number of injuries (n=47), followed by zone II (n=39). Ninety tendons were repaired using polyester suture, the most common size being 4-0. The modified Kessler technique was used in the majority of cases (n=62). Only 22 tendons underwent an epitendinous repair. Splint immobilization was used in 30 patients and a full cast in 17. The median duration of immobilization was four weeks. Forty-two patients underwent postoperative hand therapy. Using the American Society for Surgery of the Hand Total Active Motion (TAM) score, 40 of 47 patients experienced 100% recovery with no functional limitations. Two patients had a score <100%, not necessitating further surgery. A second operation was required for five patients. All patients in this group demonstrated 100% TAM at one year.

Conclusion: Pediatric flexor tendon injuries remain rare and usually involve the dominant hand holding or manipulating an object. An excellent outcome was found in 95.9% of patients assessed by TAM scores. Repair technique was chosen according to the size of tendon involved. Patients not treated with hand therapy and not immobilized in a cast were often too young to participate in rehabilitation. Based on the results, immobilization of young children for four weeks is safe and does not worsen functional outcomes. Of the patients requiring a second procedure, no predictive variables for poorer outcomes were found on analysis of age, outcome, cause, location, repair technique, rehabilitation protocol or zone of injury.