A team approach is critical to effectively address preoperative issues and enhance postoperative success.
Preoperative factors considered by the team include (1) psychosocial issues, (2) status of neural recovery, (3) musculoskeletal readiness, (4) degree of sensibility, (5) motor learning aptitude, and (6) functional requirements.
Preoperative therapy may be required to maintain or increase the strength of the muscle(s) proposed for transfer, to maximize preoperative passive range of motion and correct joint contractures, and to provide education regarding anticipated postoperative restrictions and requirements.
Therapy after surgery has three phases: (1) immobilization, (2) activation of the transfer, and (3) strengthening/return to function.
The use of custom-fabricated orthoses is an important part of the therapy program after tendon transfers.
The specifics of the surgical procedure as well as the patient’s clinical presentation will dictate the exact positioning requirement of the orthosis.
In general, the orthosis is fabricated with the joints affected by the transfer positioned to protect the resting tension of the transfer.
Familiarity with the specific surgical procedure, healing characteristics, and positioning requirements are essential in the fabrication and ongoing monitoring and modification of an upper extremity orthosis. An experienced certified hand therapist is uniquely qualified to fabricate the orthoses required.
Once neural recovery from peripheral nerve injury has plateaued, tendon transfers offer a means to enhance prehension and related function. Yet, the decision to perform tendon transfers requires a great deal of consideration preoperatively to ensure a successful outcome.
This chapter (1) outlines preoperative considerations, (2) reviews evaluations used to establish a baseline and monitor progress, and (3) considers postoperative rehabilitation methods used to foster prehensile skill after tendon transfer(s).
Tendon transfers done immediately after a traumatic injury as a salvage procedure require quick decision making by the surgeon, patient, and family. However, if tendon transfers are to be done after rehabilitation from peripheral nerve injury is complete, then a preoperative team assessment is often used to direct preoperative intervention strategies in preparation for the transfer procedure and to aid decision making regarding surgical procedures to be performed.
Benefits of a Team Assessment
A team approach can effectively address preoperative issues and enhance postoperative success. The ideal team would consist of a hand surgeon, physician assistant or nurse practitioner, hand therapist (occupational or physical therapist), electrodiagnostician, social worker, the client, and his or her family. The client’s primary therapist is also an important team member because he or she is usually the most familiar with the client’s condition. Ideally, details on current function and preoperative goals will be exchanged among team members.
Preoperative factors considered by the team include (1) psychosocial issues, (2) status of neural recovery, (3) musculoskeletal readiness, (4) degree of sensibility, and (5) motor learning aptitude.
Success with postoperative rehabilitation depends on issues such as cognition, past and current abilities/interests, client roles, motivation, and compliance. Pertinent information can be obtained from the primary therapist, family/client interview, and observations of nonverbal behavior. Cognitive screening should be done with young children and individuals with impairments that may affect tendon transfer training. The use of the Disability of the Arm, Shoulder, and Hand Questionnaire or a graphic display of the client’s roles and responsibilities may supply useful information. A record of participation in therapy and carryover with home programs can help gauge future motivation and compliance.
Poor compliance can diminish the success of tendon transfer surgery and may stem from
Denial . Many individuals believe that the situation will resolve itself or determine that because the other limb is working well, they really “don’t need to improve.”
Frustration . The client and his or her family may have made many sacrifices to attend therapy and perform exercises without sufficient gratification of nerve recovery.
Lack of trust in the therapy program . The client may not believe in the rehabilitation process or have confidence in the team members because of outcome or other issues.
Finances . Therapy visits can be very costly when time, insurance copays, and travel expenses are also an issue.
Time . Other roles as a family member, job holder, and maintainer of the household may occupy the client’s day and limit the availability to participate or attend therapy sessions.
If the underlying reasons for poor compliance can be resolved, the chance for success may improve.
Status of Neural Recovery
Before tendon transfers, the team should ensure that the opportunity for reinnervation has passed and that recovery has plateaued. For example, repeated assessment of muscle strength, sensibility, and dexterity should reveal gradual slowing in progress or lack of progress over the past few months. To verify current ability, the contribution of stabilization techniques used to augment movement and function (e.g., orthotic stabilization or neuromuscular electrical stimulation [NMES]) can be compared with the client’s individual effort (see Chapter 45 ) ( Fig. 59-1 ). Findings from electrodiagnostic tests such as electromyography or nerve conduction studies can further verify that recovery has plateaued, and provide support that the client is ready for surgical intervention.
Range of Motion
Ideally, full passive and active range of motion (ROM) should be present in the involved extremity before surgery, particularly at the associated joint(s). The involved side should be compared with the noninvolved side with a goniometer. Active ROM should also be assessed during functional tasks because the quality of the motion may differ from what is displayed during goniometry.
A strength assessment helps determine which muscles are strong enough to transfer. Although muscle physiologic cross-sectional area is proportional to maximum muscle strength, it is not easily measured. Therefore, strength is often documented with manual muscle testing or hand-held dynamometry (e.g., M500 Myometer; Jtech Medical Industries, Salt Lake City, UT) ( Fig. 59-2 ). Traditionally, a muscle must be graded as 4/5 on a standard 0 to 5 manual muscle testing scale and have sufficient excursion in the new position to be considered for transfer. Proximal muscle weakness and incoordination can reduce muscle power, resulting in substitution patterns that the therapist should be cognizant of (see Table 45-2 ). Grip and pinch dynamometers help determine prehensile strength. However, there are no established recommendations associated with dynamometry and tendon transfers.
Assessments of Dexterity/Function
Measurement of coordination, skill, and function using standardized tests can validate the client’s need for tendon transfers and document preoperative performance. Table 59-1 (online) provides a list and descriptions of useful dexterity and functional tests. (See Chapter 12 for a detailed description of functional tests.)
Degree of Sensibility
Because it plays an important role in object manipulation, , an accurate assessment of passive and active sensibility should be made. Touch pressure and discrimination are two forms of passive sensibility. The touch-pressure threshold is commonly tested with Semmes–Weinstein monofilaments , or the Weinstein Enhanced Sensibility Test, as shown in Figure 59-3 . Discrimination can be assessed with static/moving two-point discrimination using the Disk-Criminator. , An alternative is the Pressure-Specifying Sensory Device, which was designed to determine the amount of pressure required to perceive one or two metal prongs. Active sensibility or stereognosis can be tested with the Moberg’s Picking-Up Test , or the Byl-Cheney-Boczai Sensory Discriminator Test. The clinician is advised to follow the nerve distribution and assess both limbs for comparison during sensibility testing.
Motor Learning Aptitude
Activation of the muscle–tendon unit after transfer requires learning new control strategies. Preoperative motor learning ability can be measured behaviorally at four levels: acquisition, retention (consistency), transfer (flexibility), and efficiency. , Initial practice or performance of a new task involves acquisition of a skill or a control aspect of a skill. Retention or consistency is evident when a skill or some aspect of a skill can be demonstrated after a short or long time delay. Transfer or flexibility involves the ability to execute a similar skill or slight variation (e.g., altered force or timing) after a time delay. Finally, efficiency refers to the ability to minimize energy expenditure during task performance such as during the execution of fine motor activities. The ideal test would measure all four levels.
Motor learning aptitude should be assessed with the noninvolved versus the involved limb. Acquisition can be assessed by observing performance of a novel task. For example, a client could be asked to quickly place 10 small objects in a set sequence into a container (acquisition). At the next therapy session, retention could be measured by having the client repeat placement of the objects in the same order without coaching. As a transfer task, the client could be asked to place the objects in reverse order without previous review. Finally, efficiency could be measured by timing performance.
When a client does not yet meet the surgical criteria, he or she may be referred back to therapy to further improve ROM and strength. For instance, muscle wasting or contractures may have developed during the primary healing phase. It is possible that the therapeutic regimen was insufficient or compliance with the recommended protocol was poor, detracting from the outcome. These issues should be resolved before proceeding with tendon transfer surgery.
Methods to Enhance Preoperative Passive ROM
Joint contractures often interfere with successful outcome from tendon transfers. Thus, it is imperative that maximum passive ROM be achieved in the involved joints preoperatively, which can be done with static progressive orthoses or serial casting.
Serial casting can be quite effective at resolving distal contractures. It provides quick improvement in ROM by incorporating a low-load sustained stretch to shortened tissue(s). , Its use ensures client compliance because the cast cannot be easily removed. Unfortunately, prolonged cast wear may interfere with client roles, alter skin integrity, and temporarily weaken muscles needed for transfer. In those situations, a static progressive orthosis would be best ( Fig. 59-4 ).
Structures susceptible to contracture vary depending on the nerve injured. After a radial nerve injury, due to the loss of finger extension, extrinsic finger flexor muscle–tendon unit shortening may occur and this will limit combined wrist and finger extension. In this case, a forearm to finger tip serial cast or orthosis positioned at the end range of finger and wrist extension may be warranted. The orthosis can be serially adjusted to result in gradual lengthening of the shortened finger flexors and allow increased combined extension of the wrist and fingers. After a median nerve injury, the webspace between the thumb and index finger is vulnerable to an adduction contracture. A thumb webspacer orthosis or serial cast with stabilization of the metacarpophalangeal (MCP) joints of the thumb and index may help to maximize thumb abduction or extension. After an ulnar nerve injury, chronic intrinsic minus or claw posturing can lead to MCP joint hyperextension and interphalangeal (IP) joint flexion contractures. In this instance, orthoses or serial casts for MCP flexion and IP joint extension are an effective way to increase passive ROM at both joints ( Fig. 59-5 ).
Strengthening Before Transfer
Before surgery, methods to maintain or increase strength of the muscle(s) proposed for transfer should be encouraged. Biofeedback is effective in cueing individuals with various disabling conditions to activate muscles with more strength and vigor. NMES has also been used to augment muscle contraction in potential transfer muscles, as shown in Figure 59-6 . Aquatic therapy or whirlpool provides a gravity-reduced environment useful for strengthening muscle without stress and strain. Once muscle activation is sufficient, resistance can be provided in the form of free weights, cuff weights, Thera-Band (The Hygienic Corporation, Akron, OH), theraputty, exercise machines, work simulators, and computer games (e.g., Biometrics device; Biometrics Ltd., Ladysmith, VA). If prehension patterns are limited, cuff weights can provide resistance without requiring grasp of a free weight.
Postoperative guidelines should be reviewed before and after surgery to clarify expectations. Guidelines may include information regarding orthoses, therapy frequency, precautions, and activity limitations. The commitment required to achieve success from surgery should be emphasized, including the therapy timeline and the value of compliance with home exercise programs. These discussions may prompt the client to plan life events such as sports participation around the surgery schedule. Postoperative success and motivation can be enhanced by establishing realistic functional outcomes. A social worker can aid in planning for medical costs or travel to ensure postoperative therapy participation. Referral to another client who has undergone tendon transfers may enhance understanding of the experience.
Postoperative Treatment by Phase
Treatment after surgery consists of three phases: (1) immobilization, (2) activation of the transfer, and (3) strengthening/return to previous function (see Table 59-2 for goals at each phase).
|1||Protect repair site||Cast, then change to static orthosis in position that minimizes tension on the tendon transfer|
|Manage edema||Elevation, compression, active movement of noninvolved joints|
|Protect areas of diminished or absent sensibility||Education|
|Encourage active movement of noninvolved joints||Active ROM exercises and tasks|
|2||Regain active ROM||Active ROM exercises and tasks incorporating involved structures|
|Activation of tendon transfer||Use former function of the transferred tendon and the new function simultaneously; perform desired motion with contralateral limb first, then both limbs together; use of place-and-hold techniques; work in gravity-eliminated plane at first|
|Enhance sensorimotor control||Practice grasping and manipulating objects of various shapes, sizes, and textures; complex manipulative tasks|
|Sensory reeducation||Desensitization and active somatosensory training; use of “sensor glove”|
|Enhance function while maintaining appropriate biomechanical positioning at involved & noninvolved joints||Custom orthoses; practice prehensile and ADL tasks with and without orthoses|
|Maintain passive ROM at involved and surrounding joints||Passive ROM exercises, myofascial release|
|3||Improve strength||Theraputty, Thera-Band, cuff weights, exercise machines, work simulators aquatic therapy, Biometrics device|
|Enhance aerobic conditioning||Aerobic activities (e.g., arm ergometer)|
|Return to previous level of function||Work simulation; simulation of difficult ADL tasks|
|Reevaluate current status regarding; compensatory strategies; capacity for continued improvement and need for surgical intervention||Issue adaptive equipment/splints, preoperative conditioning|
Phase 1: Immobilization
After tendon transfer the limb is usually immobilized in a bulky dressing with a plaster shell at first and then a cast or custom-fabricated thermoplastic orthosis fabricated by a hand therapist for 3 to 5 weeks. Limited evidence has been published exploring the application of early motion after tendon transfers. In a clinical study of 20 patients after transfer of the extensor indicis proprius to the extensor pollicis longus to restore thumb extension, patients were treated with either immobilization or early dynamic motion (dynamic thumb extension with active, limited range flexion). The authors found that the dynamic motion group had better results after 4 weeks, but hand function was similar in both groups after 6 and 8 weeks. Patients treated with early dynamic motion recovered their hand function more rapidly than the immobilized patients, shortening total rehabilitation time and making dynamic motion treatment cost-effective. In a similar study, Rath reported that immediate postoperative active mobilization reduced rehabilitation time by an average of 19 days after opposition tendon transfer compared with immobilization. An earlier return to activities of daily living was a further benefit to patients.
A more recent study by Giessler et al. compared early free active motion with early dynamic motion with extension orthoses. Both regimens (dynamic vs. early active) achieved comparable clinical results.
Nevertheless, a period of immobilization is the more typical practice after tendon transfers and is particularly recommended for the younger or less compliant patient.
After cast removal, the client is usually referred to therapy for fabrication of an orthosis to continue to protect the integrity of the transfer. The specifics of the surgical procedure as well as the patient’s clinical presentation will dictate the exact positioning requirements. In general, the orthosis is fabricated with the joints affected by the transfer positioned to protect the resting tension of the transfer. For example, after a transfer of the flexor digitorum superficialis (FDS) tendon of the ring finger to the thumb to restore opposition, a wrist-based thumb spica orthosis may be used to position the wrist in 10 to 20 degrees of flexion with thumb opposition. If a swan-neck deformity with PIP joint hyperextension develops in the ring finger, a static three-point hyperextension block orthosis may be warranted to limit PIP joint hyperextension. A protective orthosis should be removed only for exercise and bathing.
Immediately postoperatively, limb elevation prevents distal accumulation of fluid. Exercise proximal to the surgical site also prevents edema formation and may reduce the incidence of secondary joint stiffness. Compressive garments should be used as needed.
Postoperative treatment includes interventions to prevent adhesions, increase tendon excursion, and enhance mobility at the surgical and donor sites. This can be accomplished in a few ways. One is through massage during activation of the transfer or separately, performed at least twice daily. If needed, vibration can be used to reduce pain before massage. Another method to improve soft tissue mobility and minimize hypertrophic scarring is with the use of a silicone gel sheet, which acts through a process of skin hydration. Use of an elasticized tubular bandage sleeve (Tubigrip) over the gel insert can keep it in place and increase the compression on the scar while contributing to edema control.
During the immobilization phase, the primary goal is to protect the transfer. This is accomplished with casting and orthoses. Other goals such as edema control, active ROM of noninvolved joints, and soft tissue mobility can be reinforced at home.
Phase 2: Activation of the Transfer
Mobilization of the transfer requires learning to activate the muscle–tendon unit in a new role. To recruit the transfer, the client is encouraged to move into the former and new role simultaneously. For example, if the pronator teres is transferred to a new role as a wrist extensor, the transfer can be recruited by pronating the forearm and extending the wrist at the same time ( Fig. 59-7A ). It may be easier to initiate isolated motion such as wrist extension in a gravity eliminated plane ( Fig. 59-7B ). If he or she is unable to recruit the transfer in a gravity-eliminated plane, it may be easier to first try to place the limb in the new position passively and then ask the client to hold it (place-and-hold technique). Another strategy is to perform the desired motion with the noninvolved limb first and then attempt to move the involved limb actively or move both limbs simultaneously.
The client may feel that it is necessary to move vigorously and force movement of the transfer; however, he or she must be educated to move slowly and perform short sessions of exercise to prevent fatigue of the transferred muscle. A recommended strategy is for the client to activate the transfer through 10 repetitions and then rest while attending to scar massage, edema control, and passive ROM. This sequence could be repeated three times in the session, and the orthosis reapplied at the end of the session.
Below are examples of common transfers used for the radial, median, and ulnar nerve palsies ( Table 59-3 ) along with methods to activate select transfers.
|Radial nerve||Wrist extension||Pronator teres to extensor carpi radialis longus and brevis||Avoid simultaneous wrist and digital flexion to prevent overstretching of the transfer|
|Finger extension||Flexor carpi ulnaris of flexor carpi radialis to extensor digitorum communis|
|Thumb extension||Palmaris longus of flexor digitorum superficialis to extensor pollicis longus|
|Median nerve||Opposition||Flexor digitorum superficialis, palmaris longus, or extensor digiti minim||Avoid simultaneous wrist, thumb, and finger extension|
|Thumb IP flexion (high lesions); DIP flexion of index (high lesions)||Brachioradialis to flexor pollicis longus; flexor digitorum profundus of the long, ring, and small fingers to the flexor digitorum profundus of the index finger|
|Ulnar nerve||Correct claw (control MCP joint hyperextension)||Flexor digitorum superficialis, extensor indicis proprius, extensor digiti minimi to intrinsic||Avoid full MCP joint extension; avoid simultaneous finger, thumb, and wrist extension|
|Thumb adduction||Flexor digitorum superficialis or extensor carpi radialis longus to adductor pollicis|
|Index abduction||Abductor pollicis longus, extensor carpi radialis longus, or extensor indicis proprius to first dorsal interossei|
|DIP flexion of the long, ring, and small fingers (high lesions)||Side-to-side tenodesis of flexor digitorum profundus of index finger|