Introduction
Flexor tendon injuries in children are less prevalent and have less evidentiary support as compared to the adult population. Most authors agree that immobilization protocols comprise a safe and efficacious choice. This chapter will review rehabilitative regimens and correlated literature regarding the outcomes of immobilization, early passive flexion , and true active flexion in the pediatric population. Contextual factors influencing adherence and outcomes will also be discussed. Finally, the conservative and surgical management of trigger digits and trigger thumb in children will be summarized.
Section I: Flexor Tendon Injury
Background
The literature regarding rehabilitation following flexor tendon injury includes several fundamental concepts that facilitate clinical reasoning and direct efforts in evaluation and intervention. These concepts, studied primarily in the adult population, include both necessary information regarding injury and surgery as well as therapeutic parameters that can be modulated by the treating therapist.
Elapsed time is of particular interest in time between injury and surgery, time between surgery and initiation of therapy, and total time elapsed between injury and initiation of therapy. It is suggested that an increase in any of these timeframes will have a negative impact on outcomes, as a delay in gliding of the healing tendon across adjacent structures allows adhesions to form, limiting both proximal and distal excursion for the production of motion. Multiple studies support the concept that early controlled motion is beneficial to both tendon healing and strength, while also decreasing work of flexion and subsequent adhesion formation.
Specific information related to surgical procedure, including the number of strands of suture crossing the repair site and any concomitant injuries and/or repairs help guide rehabilitative choices to facilitate gliding of the repaired tendon within and across adjacent structures. Decisions for postoperative rehabilitation are made in conjunction with the surgeon and include type of orthosis, initiation of controlled motion, and progression of exercise. Clear and consistent language has recently been suggested to describe exercise strategies. The term true active flexion should be used to describe an arc of volitional motion toward flexion. Early passive flexion is recommended for regimens incorporating passive flexion of the digit regardless of extension, and place and hold should be for those regimens that incorporate passive digital flexion with an isometric hold at end range. In addition to and as important as any surgical or therapeutic specifics, the ability of the patient to adhere to the suggested regimen and participate in the rehabilitative process is crucial to outcomes.
The first section of this chapter will examine how these fundamental concepts apply to the rehabilitation of children following flexor tendon injury. Previous studies have suggested that recovery is observed more quickly following pediatric flexor tendon repair and with fewer adhesions due to favorable blood supply and remodeling capabilities. The flexor tendons of children have been described as smaller and more delicate, requiring a meticulous surgical technique. Age categories of children, including those younger than 5, between 5 and 10, and those 11 or older have been suggested to influence suture technique, size of suture, and rehabilitative approach. These concepts have informed surgical and postoperative decision-making and, in concert with the adult literature, have afforded multiple approaches to rehabilitation that will be reviewed herein.
Rehabilitative Options
The primary controversy with regard to pediatric flexor tendon outcomes is centered on postoperative immobilization. Converse to the adult population, immobilization following pediatric flexor tendon repair continues to be suggested as producing comparable outcomes with a lessened chance for rupture during the rehabilitative phase. Four weeks has been established as the common, agreed upon maximal timeframe for immobilization. A collection of studies published between 1994 and 2006 compared immobilization protocols with early motion in children without significant differences in outcomes. High percentages of good and excellent results using early passive flexion and true active flexion have also been reported. A summary of these approaches is presented in the following sections.
Immobilization
An example of a specific immobilization protocol has been offered by Amy Lake and her surgeon colleagues at the Texas Scottish Rite Hospital for Children. This protocol delineates children into two age brackets: those 4 years and younger and those 5 years and older. Children in the younger group are immobilized in a long arm “mitten” cast with the wrist positioned in 20–25 degrees of flexion, the metacarpophalangeal (MP) joints in 50–60 degrees of flexion, and the interphalangeal (IP) joints in mild flexion for 4 weeks. The older group is immobilized in the same position for only 3 weeks.
Progression for both age groups is guided by number of weeks following the immobilization phase. During the first week after the cast is removed, children are placed in a dorsal blocking orthosis with the wrist positioned in neutral and distal joints maintained in mild flexion. As rationale for this continued, open-packed position, the authors offer a greater concern with attenuation of the repair and resultant swan neck deformities versus IP extensor lags. During the first postimmobilization week, the children and their caregivers are educated on initiation of passive protected extension (Duran’s passive range of motion) in the splint, and wrist active motion with relaxed digits performed out of the splint.
Over the course of the subsequent second through fifth week after immobilization, true active flexion is progressed using a percentage approach. During the second week, children are encouraged to create true active flexion to 25% of full effort (fifth to sixth postoperative week), the third week 50% (sixth to seventh postoperative week), fourth week 75% (seventh to eighth postoperative week), and during the fifth week (eighth to ninth postoperative week) the child is encouraged to demonstrate true active flexion with 100% of their effort. The orthosis is typically weaned during the third week after the cast has been removed (sixth to seventh postoperative week).
Outcomes of immobilization following flexor tendon repair in children have been published by Elhassen et al. The authors employed a retrospective design of children who had been treated with immobilization compared to those progressed through early passive flexion . No significant differences were found in total active motion between the two groups. Final outcomes in both groups included good to excellent results; children with zone I injuries and those without concomitant nerve repairs were noted to have better outcomes. The authors reported two complications, both in the immobilization group, including a 2-year-old child who sustained tendon rupture and one 6-year-old who developed joint stiffness requiring tenolysis. Each of these children ultimately achieved good outcomes. This study supports the use of immobilization following flexor tendon repair in children as similar to early passive flexion .
Early Passive Flexion
Moehrlen et al. focused solely on the assessment of early passive flexion using age groupings: up to 4 years, 4–10 years, and 10–16 years. Forty-nine tendons were repaired in 39 children using a two-strand core suture with a modified Kessler technique. The sample was not limited to zone II injuries. Postoperative orthoses were positioned in 45 degrees of wrist flexion with the MPs and IPs in extension; immobilization was extended proximal to the elbow in children younger than 4. Rationale for wrist positioning was not provided by the authors.
Similar to immobilization protocols, children in this study were progressed through postoperative rehabilitation based on age. Early passive flexion and active-assisted extension via Kleinert traction were pursued during the first 3 weeks after surgery in all age groups, and children were immobilized in flexion between exercises. The youngest group of children, less than 4 years old, received assisted finger mobilization during therapy at 3 weeks and returned to activity at week 7. Those children between 4 and 10 years old began true active flexion at 4 weeks and were encouraged to discontinue the orthosis and resume full activity after 8 weeks. Children greater than 10 ears old also initiated true active flexion at 4 weeks and resistance of the exercise was gradually increased through the eighth postoperative week. The oldest children remained in their orthoses until the 10-week point. Moehrlen et al. reported good or excellent results in 93% of these cases with no subsequent ruptures. The authors found no statistically significant differences in total active motion or Strickland’s percentage between age groups; however, children with zone II injuries were noted to have significantly lower Strickland’s percentages than children with injuries in other zones.
True Active Flexion
Although cast immobilization through the fourth postoperative week is considered the norm, some international authors have reported successful results in pursuing early mobilization following flexor tendon repair in children. Nietosvaara and colleagues in Finland completed a retrospective review of 45 fingers in 28 children, including two-, four-, and six-strand repairs. Eleven fingers were treated with an immobilization protocol and casted for an average of 27 days, 1 was treated using elastic traction, and 33 fingers were treated with an active motion protocol initiated 1–3 days following repair. The average age of children in this study was 10 years, ranging from 3.2 to 15.9 years and including 21 boys and 7 girls. The active motion protocol included application of a dorsal blocking orthosis with the wrist held in a neutral position, MPs flexed to approximately 60 degrees and IPs held in extension. The orthosis was removed for active exercises four times a day including five repetitions of synergistic exercise: passive wrist flexion with active digital extension followed by wrist extension with true active flexion . The exercises were completed by the patient, caregiver, or therapist completing passive digital flexion through the available range.
According to Strickland’s original criteria, good and excellent results were noted in 36 fingers in this study. Ninety-four percent of fingers in the mobilization group achieved these results as compared to only 62% in the immobilization group. Three fingers with two-strand repairs sustained tendon rupture; two following cast immobilization and the 1 patient for which elastic traction was used. All cases of rupture were in male patients. The authors in this study concluded that true active flexion can be used for children older than 5 years, and delineated age groupings for number of strands as opposed to length of immobilization. Six-strand repairs were suggested for zone I and II injuries in adolescents, while four-strand repairs were advocated for younger children and zone V repairs.
A more recent study completed by Al-Qattan in Saudi Arabia retrospectively reviewed 44 children ranging from 5 to 10 years of age whose tendons were repaired using a six-strand core technique achieved through “figure of eight” sutures and venting of the proximal pulley. The children were placed in a dorsal blocking orthosis with the wrist in 30 degrees of flexion, MPs in 30–40 degrees of flexion, and IPs fully extended. True active flexion and extension were initiated immediately following surgery; the orthosis was discontinued after 4 weeks. Excellent results were reported in 85% of cases with the remainder classified as good results; no complications were reported by the authors.
The aforementioned literature, while disparate in both surgical and rehabilitative suggestion, typically employs age as a factor that influences decision-making in the pediatric population. In both immobilization and early passive flexion regimens, children under the age of four are immobilized proximal to the elbow postsurgically, and those 5 and older initiate true active flexion during the fourth postoperative week. One true active flexion study, in comparison, focused age-related choices on surgical repair and number of strands. Despite previous research suggesting no difference in rehabilitative outcomes, the more recent studies indicating greater than 90% good and excellent results with early passive and active protocols provide promising evidence for consideration (see Tables 20.1 and 20.2 ).
| Postoperative | Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Week 9 | Week 10 | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Texas Scottish Rite | <4 years | Long arm mitten cast 20–25 degrees wrist flexion 50–60 degrees MP flexion Mild flexion IP joints | Dorsal block orthosis with wrist neutral Duran’s PROM Wrist AROM | 25% true active flexion | 50% true active flexion Wean orthosis | 75% true active flexion | 100% true active flexion | |||
| >5 years | Long arm mitten cast 20–25 degrees wrist flexion 50–60 degrees MP flexion Mild flexion IP joints | Dorsal block orthosis with wrist neutral Duran’s PROM Wrist AROM | 25% true active flexion | 50% true active flexion Wean orthosis | 75% true active flexion | 100% true active flexion | ||||
| Moehrlen et al. (2009) | <4 years | Long arm orthosis 45 degrees wrist flexion MP and IP extension Passive digital flexion and active-assisted extension via Kleinert traction | Assisted finger mobilization | Return to activity | ||||||
| 4–10 years | Dorsal blocking orthosis 45 degrees wrist flexion MP and IP extension Passive digital flexion and active-assisted extension via Kleinert traction | True active flexion | Discontinue orthosis Return to activity | |||||||
| 10–16 years | Dorsal blocking orthosis 45 degrees wrist flexion MP and IP extension Passive digital flexion and active-assisted extension via Kleinert traction | True active flexion with increasing resistance | Discontinue orthosis Return to activity | |||||||
| Nietosvaara et al. (2007) | >5 years | Dorsal blocking orthosis: Wrist neutral, 60 degrees MP flexion, IPs extended Synergistic exercise 4×/day, 5 repetitions: Passive wrist flexion with active digital extension, wrist extension with true active flexion Passive digital flexion | ||||||||
| Elhassen et al. (2006) | Moehrlen et al. (2009) | Nietosvaara et al. (2007) | |
|---|---|---|---|
| Design | Retrospective comparison of immobilization versus early passive flexion | Retrospective comparison of three age groups using early passive flexion | Retrospective comparison of true active flexion versus immobilization |
| Subjects | 41 fingers (35 patients) Mean age 7 years (range 2–15) | 49 fingers (39 children) Mean age 6 years (range 1.2–14.8) | 45 fingers (28 children) Mean age 10 years (range 3.2–15.9) |
| Groups | 22 early passive flexion 19 immobilized | <4 years: 8 subjects 4–10 years: 18 subjects 10–16 years: 13 subjects | 33 true active flexion 11 cast immobilization 1 elastic bands |
| Results |
|
|
|
| Complications | 1 rupture, 1 tenolysis Both in immobilization group | 1 tenolysis due to surgical error No ruptures | 3 ruptures of two-strand repairs: 1 elastic bands, 2 immobilization |
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