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Flexor Tendon Therapy Guidelines

Information

Description of Intervention1-6

The two primary flexor tendons of the hand are the flexor digitorum profundus (FDP), which is a flexor of the distal interphalangeal (DIP) joint that also assists with proximal interphalangeal (PIP) and metacarpophalangeal (MP) flexion, and the flexor digitorum superficialis (FDS), which is a flexor of the PIP joint that also assists with MP flexion. Any thumb flexor tendon injury would result in an FPL laceration.  Other flexor tendons in this region are the flexor pollicis longus, flexor carpi radialis, and flexor ulnaris, which are primarily involved in wrist flexion. Injuries to the FDP and FDS tendons are among the most common hand injuries, and they typically occur secondary to lacerations or other forms of trauma to the wrist. Flexor tendon injuries are divided into five zones (zones I–V), each of which carries a unique prognostic implication, with injuries to zone II and zone III being the most common. But regardless of the location, most flexor tendon injuries require surgical repair.

After flexor tendon repair, it is imperative for patients to undergo an intense, comprehensive hand therapy program with the goals regaining hand function, reducing the risk of rupture, and minimizing adhesions. Numerous rehabilitation protocols for flexor tendon rehab may be followed, but all fall under one of three main categories: immobilization, passive mobilization, and early active mobilization. Although surgical techniques and rehabilitation protocols have improved significantly over time, it remains challenging to achieve optimal outcomes after flexor tendon repair, and it is unclear which of these rehabilitation protocols is best.

Immobilization is typically recommended for children, noncompliant patients, and patients with concomitant intra-articular fractures, but the optimal indications for passive mobilization and early active mobilization and specific protocols within are less clear. The Kleinert protocol, which allows for passive flexion at the MP and PIP joints, was the gold standard for a long while, but research has shown it can also lead to PIP stiffness due to volar plate contraction. Several other therapeutic protocols have since been developed, and determining the ideal protocol depends on many factors, including therapist preference and injury location and severity.

Indications for Intervention

Flexor tendon therapy is indicated after surgical repair of one or more flexor tendons to facilitate the recovery of hand and finger function.

Evaluation

  1. Ask the patient to describe their medical history, with a focus on the event that led to the flexor tendon injury and the surgical procedure performed.
  2. Ask if the patient has any comorbidities, including diabetes, osteopenia/osteoporosis, cardiovascular issues, or a history of smoking.
  3. Perform a physical examination of the hand and wrist.
  4. Measure the active and passive range of motion (ROM) of the joints involved and compare these values with those of the contralateral side.
  5. Measure the distance of distal pulp from the distal palmar crease to assess the results of the flexor tendon repair.
  6. Assess skin integrity to help localize potential sites of tendon injury.
  7. Ask the patient to rate their pain on the visual analogue scale (VAS) or a similar pain scale.
  8. Consider using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, which is used to assess impairment of the upper extremity.
  9. Other parameters that may be evaluated include task performance with a hand function test, power grip with a hand dynamometer, pinch grip with a hydraulic pinch gauge, and dexterity with a pegboard.7-9

Intervention Options: Rehabilitation Protocols4,6,9,10

As stated above, the three established rehabilitation regimens are immobilization, passive mobilization, and early active mobilization:

Immobilization

  • Immobilization is typically reserved for younger children who are unable to follow directions, elderly patients with cognitive deficits, and other patients that may be noncompliant with rehabilitation
  • These patients are outfitted with either a long- or short-arm orthosis with no passive or active motion exercises for 3 approximately weeks; 3 weeks after surgery, the wrist position may be changed to neutral
  • The exercise regimen should begin at the discretion of the hand therapist and proceed cautiously, as immobilized tendons are generally weaker due to the lack of stress applied as they heal

Passive mobilization

  • Passive mobilization involves outfitting the patient in an orthosis after surgery—usually within 3–5 days—that places the wrist and finger joints in passive flexion; patients typically complete passive mobilization and place-and-hold active mobilization exercises with a rubber band for the next 3–4 weeks, then move on to resistance-free active exercises after the orthosis is removed
  • Several passive mobilization protocols may be used, with the two most popular being the Kleinert protocol and Duran protocol/modified Duran protocol; others include the St. John protocol and the Manchester protocol

Kleinert protocol

  • Patients are outfitted in a dorsal blocking splint, which is typically fabricated by attaching a rubber band or elastic thread to the involved finger(s) through a suture through the nail or hook glued to the nail, which pulls the involved finger(s) into complete PIP and DIP flexion and attaches to the volar forearm or a volar strap; a pulley or bar on a palmar component further ensures both the DIP and PIP joints are in full flexion
  • Patients should then be encouraged to complete active extension exercises by extending their fingers against the resistance of the rubber band or elastic as far as the splint will allow as often as possible (about 50 repetitions each hour); patients should also complete passive flexion exercises of the PIP and DIP joints and composite passive flexion exercises for each of the 5 digits (about 5 repetitions per hour)
  • The splint is removed 3 weeks later, at which point resistance-free active exercises should begin and continue for the next 3–5 weeks

Duran protocol/Modified Duran protocol

  • The original Duran protocol involved an orthosis that stopped at the PIP joints to allow for visualization of full PIP extension during exercises and included rubber band traction, but PIP joint contractures were common with this orthosis; this feature was eliminated in the modified Duran protocol
  • In the modified Duran protocol, a dorsal forearm-based blocking splint is used, which incorporates the full length of the fingers and straps the fingers in full extension overnight, thereby reducing the risk for PIP joint contractures:
    • For repairs in zones 1–3, the wrist is placed in 20° extension with the MP joints in 30–40° flexion and the PIP and DIP joints at 0°
    • For repairs in zones 4–5, the wrist is placed at 0°, the MP joints at 60–75° flexion, and DIP and PIP joints at 0°
  • Patients should be instructed to perform passive flexion and active extension exercises to each individual finger joint and to the entire finger on an hourly basis

Early active mobilization

  • Early active mobilization involves a dorsal forearm-based orthosis that is applied within 3–5 days after the tendon repair—as with passive mobilization—but the orthosis does not feature any elastic mechanisms
  • In a typical early mobilization protocol, the orthosis is worn 24 hours per day for 5 weeks, then at night only for 3 additional weeks
  • Complete active mobilization exercises should begin as soon as the orthosis is outfitted
  • Active blocking exercises and full passive flexion are usually initiated 1 week after surgery, while loading exercises and light activities of daily living are started 6 weeks after surgery, and full use permitted after 12 weeks
  • One early active mobilization protocol is called the Indiana protocol, which is typically indicated for patients with minimal edema and complications
    • Patients are outfitted with a hinge splint that includes an additional insert used to allow limited wrist extension
    • Patients should be instructed to place their fingers in full passive flexion, which they hold while actively extending the wrist
Diagnoses Where This Intervention May be Relevant
Comments and Pearls
  • Research has shown that early mobilization after flexor tendon repair helps to increase tendon excursion and reduce adhesion formation.6
  • Although there is a trend toward progressive active protocols, there is still a need for prospective intervention studies of high methodological quality to support the superiority of true active over passive mobilization with place and hold.9
  • Factors affecting the outcome of primary repair are tendon rupture, adhesion formation, PIP joint contracture, severity of trauma, surgical skill, and the quality of postoperative rehabilitation.4
  • Flexor tendon repair tends to have superior outcomes in children than adults due to more rapid tendon healing in children.11
  • An ideal rehabilitation protocol for flexor tendon repair should allow enough excursion to prevent adhesion formation without adding excessive stress that compromises the repair.12
  • Research suggests that there is a higher risk of decreased postoperative digital ROM with passive mobilization and a higher risk of rupture in active mobilization protocols.12
  • Many hand therapists integrate a couple of protocols into individual treatment plans dependent on the injury, timeliness of repair, quality of repair along with number of strands crossing the repair site, medical comorbidities and, reliability of the patient.
References
  1. Ahmad M, Hussain SS, Tariq F, Rafiq Z, Khan MI, et al. Flexor tendon injuries of hand: experience at Pakistan Institute of Medical Sciences, Islamabad, Pakistan. J Ayub Med Coll Abbottabad 2007;19(1):6-9. PMID: 17867470
  2. Theuvenet WJ, Kauer JM, Koeijers GF, Borghouts JM. The Kleinert dynamic splint: where it fails and how it can be modified. Ann Chir Main Memb Super 1993;12(3):200-205. PMID: 7694617
  3. Knight SL. A modification of the Kleinert splint for mobilisation of digital flexor tendons. J Hand Surg Br 1987;12(2):179-181. PMID: 3624971
  4. Frueh FS, Kunz VS, Gravestock IJ, Held L, Haefeli M, et al. Primary flexor tendon repair in zones 1 and 2: early passive mobilization versus controlled active motion. J Hand Surg Am 2014;39(7):1344-1350. PMID: 24799144
  5. Stonner MM, Keane G, Berlet L, Goldfarb CA, Pet MA. The Impact of Social Deprivation and Hand Therapy Attendance on Range of Motion After Flexor Tendon Repair. J Hand Surg Am 2022;47(7):655-661. PMID: 35623922
  6. Xu H, Huang X, Guo Z, Zhou H, Jin H, et al. Outcome of Surgical Repair and Rehabilitation of Flexor Tendon Injuries in Zone II of the Hand: Systematic Review and Meta-Analysis. J Hand Surg Am 2022. PMID: 35131113
  7. Chang M, Jung NH. Comparison of Task Performance, Hand Power, and Dexterity with and without a Cock-up Splint. J Phys Ther Sci 2013;25(11):1429-1431. PMID: 24396204
  8. Becker SJ, Bot AG, Curley SE, Jupiter JB, Ring D. A prospective randomized comparison of neoprene vs thermoplast hand-based thumb spica splinting for trapeziometacarpal arthrosis. Osteoarthritis Cartilage 2013;21(5):668-675. PMID: 23458785
  9. Chevalley S, Tenfalt M, Ahlen M, Stromberg J. Passive Mobilization With Place and Hold Versus Active Motion Therapy After Flexor Tendon Repair: A Randomized Trial. J Hand Surg Am 2022;47(4):348-357. PMID: 35190217
  10. Edinburg M, Widgerow AD, Biddulph SL. Early postoperative mobilization of flexor tendon injuries using a modification of the Kleinert technique. J Hand Surg Am 1987;12(1):34-38. PMID: 3805641
  11. Nietosvaara Y, Lindfors NC, Palmu S, Rautakorpi S, Ristaniemi N. Flexor tendon injuries in pediatric patients. J Hand Surg Am 2007;32(10):1549-1557. PMID: 18070643
  12. Starr HM, Snoddy M, Hammond KE, Seiler JG, 3rd. Flexor tendon repair rehabilitation protocols: a systematic review. J Hand Surg Am 2013;38(9):1712-1717 e1711-1714. PMID: 23981421
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