Treatment of Flexor Tendon Injuries: Therapist's Commentary Pam Steelman, PT, CHT
The Philadelphia Hand Center Philadelphia, Pennsylvania
herap y following flexor tendon repair has evolved from a philosophy of maximum protection by immobilization after surgical repair to early active range-of-motion (ROM) programs. This evolution has occurred because of advances in suture technique and the development of stronger suture materials. Scientific research has also revealed that stressed tendons heal faster, gain tensile strength faster, and have fewer adhesions and better excursion than unstressed tendons.v" Therapists should have a thorough understanding of the basic principles of the early active ROM philosophy before utilizing the techniques on the patients they treat. Several factors exclude individuals from participation in early active ROM programs. These include the use of traditional suturing methods and materials, the presence of edema, an individual's inability to attend regular therapy sessions, the presence of a pre-existing condition that affects wound healing or soft tissue physiology, and patient noncompliance. Patients should be carefully interviewed and evaluated to determine the best rehabilitation option. In order for the therapist to choose the appropriate tendon rehabilitation program, certain essential elements should be known. The therapist must be aware of the suturing technique utilized, the integrity of the blood supply, the condition of the tendon and surrounding structures, the type of repair accomplished, and the level and extent of injury. Early active ROM programs are appropriate in repairs using stronger suture techniques.' These suture techniques were documented and referenced in the previous paper. The therapist must also know the exact date of the tendon repair. This information will be important in determining tissue strength. Tissue strength is now well documented through the stages of wound repair. Tensile stress demands
T
This paper is preceded, on p. 141, by a paper presenting a hand surgeon's perspective on the same subject. Correspondence and reprint requests to Pam Steelman, PT, CHT, The Philadelphia Hand Center, PC, 834 Chestnut Street, Suite G114, Philadelphia, PA 19107.
TABLE 1.
Tensile Stress on Normal Flexor Tendons (Conservative Working Numbers)*
Activity
Stress (g)
Passive motion Light grip Strong grip Tip pinch-index FDP
500 1500 5000 9000
FDP indicates flexor digitorum profundus. *When tensile strength of a tendon repair is calculated to gauge activity tolerance, notice that repairs of the flexor digitorum superficialis can tolerate less than 30% of the stress values listed. NOTE:
TABLE 2. Estimated Unstressed Repair Strength with Horizontal Mattress Running-lock Epitendinous Suture
Repair Strength (g)
Two-strand Four-strand Six-strand
o Weeks
1 Week (-50%)
3 Weeks (-33%)
6 Weeks (+20%)
2500 4300 6000
1200 2150 3000
1700 2800 4000
2700 5200 7200
on tendons are listed in Tables 1 and 2 and can be used to determine when to add various activities into the rehabilitation program, according to wound strength. 1,4,sThe primary concept to consider is that activity loads can be increased provided they are kept below the rupture strength of the repair site. The therapist must gather information about complicating and pre-existing medical problems that affect wound healing and soft tissue physiology. The presence of edema excludes an individual from participation in an early active ROM program, since the edema provides resistance to the tendon during ROM activity and can account for as much as a 25% increase in the "work of flexion."l This also accounts for the rationale to defer institution of active ROM until the third postoperative day or later, when edema is less likely to be present. It is the therapist's responsibility to provide the patient with the information necessary to succeed in this program and demonstrate their comprehension of this information. April-June 1999
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Several early active ROM programs have been described in the literature. An early, well-documented protocol was described by Allen" in 1987. This program introduced a protocol of splinting coupled with gentle active digital motion, which was progressed over a six-week period. Several other protocols followed, including those described by Small et al.," Cullen," and Gratton." Each of these early programs prescribed splinting the wrist and metacarpophalangeal (MP) joints in some degree of flexion and progressed to activities within the splint according to patient tolerance and response to treatment. Currently, most early active motion programs subscribe to the theory that light active digital flexion carried out with the wrist in extension is safe for flexor tendons repaired with a four-strand core suture technique augmented by a running-lock epitendinous suture.l"!' These current programs are founded on a study by Savage, in 1988,12 which demonstrated that force requirements for active digital flexion decrease when the wrist is held at 45° of extension. Midrange active ROM exercise, as well as place-and-hold flexion exercise, is performed with the wrist held passively at 45° of extension and the MP joints held 90° of flexion." Based on these principles and earlier successful active motion programs, we have developed and successfully implemented the following program among our flexor tendon patients without incidence of rupture over the past 18 months. We feel it is safe, easy to administer, and effective in producing excellent postoperative results. Ideally, patients will be followed by the therapist two or three times weekly. This ensures that the patient's progress and tendon integrity can be monitored accurately and that the therapy program is kept appropriate for the patient's current status. The patient is seen in therapy on the first postoperative day for dressing change and fabrication of a static dorsal splint. The splint positions the wrist in neutral, the MP joints in approximately 40° of flexion, and the interphalangeal (IP) joints in neutral. Velcro straps are positioned to hold the IP joints in neutral extension during sleep. Rubberband flexion is utilized only in cases requiring maximum protection. The patient is sent home with a light dressing, with the splint in place in the nightresting position, and with instructions to return to therapy on the third postoperative day. On the patient's return therapy visit, the splint and dressing are removed, the surgical wound is observed, and the therapy session is begun. The patient is started on a standard program of protected passive ROM exercises. If no edema is present, then light active ROM exercises under therapist supervision are added. These exercises are carried out as follows: 1) The therapist manually holds the patient's involved wrist in 20° of extension. 2) The patient is instructed to actively attempt to touch his or her fingertips to the tip of the thumb, which has been positioned in palmar abduction. 3) The patient is instructed to cease active flexion at any point that 150
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pain or strong tension is experienced. 4) The patient's wrist is dropped to 20° of flexion and he or she is instructed to reverse the active motion to achieve neutral digital extension. 5) The process is repeated 10 to 15 times and is performed for three separate sessions. These sessions can be alternated with sessions of protected passive ROM exercise or rest periods, according to patient tolerance and reaction. The patient's wounds are redressed, and the splint is reapplied following the ROM session. The patient is sent home with a home exercise program consisting of passive digital flexion and active digital extension exercises performed in the splint, ten repetitions per hour. The patient is instructed to wear the splint with the IP joints strapped in neutral between exercise sessions. The patient is instructed to decrease exercise repetition or frequency, or both, if pain or edema occur. On the third therapy visit, place-and-hold flexion exercises are added to the patient's in-office therapy activities. These exercises are performed under therapist supervision with the wrist manually held in 20° of extension. The degree of flexion achieved by the digits depends on the degree of pain and tension created by the activity in any given session. No other additions or changes are made to the therapy program until the patient reaches the third postoperative week. Scar care is initiated after suture removal has been accomplished. When the third postoperative week passes, the patient is then instructed to perform light active fist-making with the wrist at 20° of extension, followed by active digital extension to neutral with the wrist dropped to 20° of flexion. The patient performs this activity only in supervised therapy for several visits and is then allowed to add this activity to the home exercise program. The patient is cautioned to avoid digital extension while the wrist is in an extended position. At the fourth postoperative week, the splint is modified to position the wrist at 20° of extension, and the Velcro straps that hold the IP joints in extension are eliminated. At the fifth postoperative week, the splint is discontinued and active blocking exercises are initiated in all digits except the small one. At this point a program of light pick-up activities is also begun and the patient is encouraged to use the hand in this way at home. The patient is cautioned to avoid making a tight fist or using the hand to grip or lift objects with any force. Finally, at six weeks, light resisted activities are added to the therapy program and are progressed to tolerance. Therapy is discontinued when functional active ROM has been achieved or a plateau is reached. If at any point during the rehabilitation period contractures begin to develop, appropriate splinting measures are added. Programs are modified and progressed according to individual needs. Specifically, we apply the generally accepted principles that excellent tendon glide achieved early indicates increased risk for rupture, and early tendon adhesion warrants more rapid progression of activity.
Our results have been uniformly good to excellent using this protocol. The program is simple and straightforward and can be easily understood by the patient. Compliance can be monitored by patient interview. The most difficult situation we have encountered has been curtailing functional use of the hand outside of therapy. This may be because of patients' perception that ROM achieved during therapy activities can be translated to normal activities. For this reason, patient education must be thorough and frequent. The program described here does not represent the definitive flexor tendon rehabilitation protocol for all patient populations. It is a program based on accepted force values for specific hand activities and accepted wound capabilities designed for patients who have had the following repair: a 3.0Ethibond two-strand double-grasping core suture with a 6.0-Proline epitendinous cross-stitch as described by Silfverskiold, All the biomechanical and physiologic principles mentioned above should always be considered as the therapist builds the components of the individual hand rehabilitation program. The definitive rehabilitation program will always take account of the specific surgical technique as well as individual factors in program design. As surgical tools and techniques continue to advance, flexor tendon rehabilitation will require less protection and will include more activity. We must continue to validate our therapeutic procedures with research and explore the limits to which
we can advance our tendon programs. As long as we use science to guide us we will be prepared to provide the highest level of care for the hand-injured population.
REFERENCES 1. Strickland JS. The Indiana method of flexor repair. In: Taras JS, Schneider LH (eds) . Atlas of the Hand Clinics. Philadelphia, Pa .: W B Saunders, 1996:77-103. 2. Gelberman RH, Woo SL-Y. The physiological basis for application of controlled stress in the rehabilitation of flexor tendon injuries. J Hand Ther. 1989;2:66. 3. Strickland JW. Flexor tendon injuries, Part I: foundations of treatment. J Am Assoc Orthop Surg. 1995;3:44-54. 4. Bright OS, Urbaniak JS. Direct measurements of flexor tendon tension during acti ve and passive digit motion and its application to flexor tendon surgery. Orthop Trans. 1977;1: 4-5. 5. Schuind F, Garcia-Elias M, Cooney WP, et al. Flexor tendon forces: in vivo measurements. J Hand Surg. 1992;17A:291-8. 6. Allen BN. Ruptured flexor tendon tenorrhaphies in zone II: repair and rehabilitation. J Hand Surg. 1987;12A:18. 7. Small J, Brennen M, Colville J. Early active mobilisation following flexor tendon repair in zone 2. J Hand Surg. 1989; 14B:383. 8. Cullen K. Flexor tendon repair in zone 2 followed by controlled active mobilization. J Hand Surg. 1989;14B:392. 9. Gratton P. Early active mobilization after flexor tendon repairs. J Hand Ther. 1993;6:285-9. 10. Cooney WP, In GT, An KN . Improved tendon excursion following flexor tendon repair. J Hand Surg. 1989;2:102-6. 11. Cannon NM. Post flexor tendon repair motion protocol. Indiana Hand Center Newsletter. 1993;1:13-7. 12. Savage R. The influence of wrist position on the minimum force required for acti ve mo vement of the interphalangeal joints. J Hand Surg. 1988;13B:262-8.
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