PRINCIPLES 
What should the patient’s joints be assessed for prior to considering a tendon transfer?
1. Mobility
2. Contracture
What is a prerequisite for successful outcome of tendon transfers?
Flexibility of the joint to be moved by transferred tendons.
What are the goals of preoperative therapy?
Maintain passive mobility.
Prevent joint contractures.
What factors need to be considered when selecting a donor muscle for tendon transfer?
1. Adequate strength
2. Tendon excursion
3. Straight line of pull
4. Synergism of action between the donor and recipient muscles
5. Expendable donor
6. Tissue equilibrium
What geometric feature correlates with the strength of a muscle?
Cross-sectional area of the muscle.
What does the work capacity of a muscle correlate with?
Muscle volume.
What does muscle excursion correlate with?
Muscle-fiber length.
How much tendon excursion can be found in wrist flexors and extensors?
30 mm.
What is the amplitude of tendon excursion for finger extensors and flexors, respectively?
1. 50 mm
2. 70 mm
Thus, when wrist tendons are used to restore finger function, there is usually incomplete correction.
How can the effective amplitude of tendon excursion be increased?
1. Increasing the number of joints the muscle tendon unit crosses.
2. Dissection of the muscle from its surrounding fascial attachments.
RADIAL NERVE 
What is the most significant limb dysfunction after radial nerve palsy?
Inability to extend the wrist and stabilization for all other hand activities.
What is the effect of restoring active wrist extension on grip strength?
Grip strength will increase three to fivefold.
What is the advantage of maintaining active wrist motion?
Tenodesis effect.
What is the tenodesis effect?
Finger extension with wrist flexion. Try this on yourself.
What are the indications for tendon transfer?
Insufficient recovery of function after nerve injury that has been observed for an appropriate length of time.
What is often considered as an early tendon transfer within weeks after nerve injury?
Single tendon for wrist extension (e.g., pronator teres to ECRB) as an internal splint.
What is the advantage of the early tendon transfer?
Facilitates power grip by wrist extension, and finger extension through tenodesis effect.
What is the preferred timing for the delayed tendon transfers?
6 to 18 months.
In general what are the available donor muscles for tendon transfers in radial nerve palsy?
All extrinsic median and ulnar nerve innervated muscles.
What muscle tendon transfers are included in the Brand transfer for radial nerve palsy?
1. PT to ECRB
2. FCR to EDC
3. PL to EPL
Thus, wrist, finger, and thumb extension, the critical deficits in radial nerve palsy, are restored.
What is the Boyes tendon transfer?
A tendon transfer for radial nerve palsy includes:
1. PT to ECRB
2. FDS III to EDC
3. FDS IV to EIP and EPL
4. FCR to APL and EPB
What is the advantage of the Boyes transfer?
It can be used in patients who do not have a palmaris longus.
What is the disadvantage of the FDS III and IV tendon transfer?
Bowing of the donor digits.
What tendon transfers are included in the FCU transfer for radial nerve palsy?
1. PT to ECRB
2. FCU to EDC
3. PL to EPL
What is the preferred tendon transfer to restore active wrist extension in a radial nerve palsy?
PT to ECRB.
What muscle tendon transfers can be used for restoration of MPJ extension?
1. FCR to EDC
2. FCU to EDC
3. FDS III to EDC
What is the theoretical advantage of the FDS III to EDC transfer in restoration for MPJ extension?
1. Straight line of pull
2. Expendable donor
3. Sufficient strength
4. Sufficient excursion
5. Synergism
What are potential disadvantages of the FCU to ECRB transfer?
Weakness of wrist flexion with wrist radial deviation deformity and unnecessary strength of wrist extension.
What is the primary choice for restoration of finger extension?
FCR to EDC transfer.
Why does the FDS III transfer not interfere with the flexor power of the other three FDS muscles?
Because the FDS III has a separate muscle belly.
What are the two functions of the functioning EPL?
1. Thumb IP extension
2. Thumb adduction
How can the PL to EPL transfer restore thumb abduction in addition to thumb extension?
Rerouting the EPL from the third dorsal compartment and allowing it to lie along the first dorsal compartment will convert its adduction moment into an abduction moment.
Which anatomic route is used for the FDS III to EDC tendon transfer?
FDS III tendon is rerouted through a large window in the interosseous membrane of the forearm.
What is the position of immobilization after tendon transfers for wrist extension, finger extension, and thumb extension?
1. 90-degree elbow flexion
2. Neutral forearm rotation
3. 45-degree wrist extension
4. Full extension of MPJ
5. Thumb abduction and full extension of IP and MPJ
When should dynamic splinting be initiated?
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