Spastic Dysfunction of the Elbow

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CHAPTER 72 Spastic Dysfunction of the Elbow

Ann E. Van Heest

CEREBRAL PALSY

Cerebral palsy (CP) is a nonprogressive perinatal injury to the developing central nervous system (CNS). CP produces motor dysfunction, movement disorders, weakness, and impaired function.³⁶ The incidence of CP is 1 to 7 per 1000 children worldwide, and 2 to 3 per 1000 in developed countries.³³ The incidence has been fairly constant over the past 40 years; a lesser incidence due to improved prenatal and perinatal care, balanced with a greater incidence of enhanced survival of the very preterm births, has lead to a net constant incidence over time.⁷

The etiology of CP has been described as a causal pathway with a sequence of conditions culminating in injury to the CNS. A recent 15-year review of the incidence of CP determined that risk factors for preterm infants were periventricular leukomalacia (magnetic resonance imaging evidence of brain structural changes), prolonged rupture of membranes, and patent ductus arteriosus. Risk factors for infants with a gestational age of greater than 34 weeks included size small for gestational age, neonatal transfer (patient transfer at birth from the hospital where they were delivered to a hospital with higher levels of care), and a history of sepsis or meningitis.³⁹

CP is most commonly classified by its anatomic distribution (Box 72-1). Diplegic refers to involvement of both lower extremities. Hemiplegic is involvement of one upper and one lower extremity on the same side. Triplegic is involvement of one upper and both lower extremities. Quadriplegic is involvement of all four limbs. The type of muscle tone is attributed to manifestations of CNS dysfunction and further classifies the disorder to include spasticity, dystonia (athetosis), flaccidity, or mixed patterns.

BOX 72-1 Simple Classification of Cerebral Palsy

Geographic Distribution

^*Hemiplegia: principally one-sided (one arm, one leg)

Diplegia: principally lower extremity involvement (two legs)

Triplegia: one arm and both legs involvement

Quadriplegia: all four extremities involvement

Type

^*Spastic: increased stretch reaction

Dystonic: ataxias, athetosis, chorea

Flaccid: lack of movement

Mixed: spastic and dystonic

^* Most elbow problems occur in spastic hemiplegia, although occasionally those with quadriplegia develop fixed contracture.

Life priorities for individuals with CP differ due to their motor system disabilities. According to Bleck, the top four self-reported life priorities for individuals with CP were, in order of importance, (1) communication with others; (2) ability to perform activities of daily living, particularly personal hygiene; (3) mobility in the community; and (4) walking.² As our society becomes more technologically sophisticated, use of the upper extremities becomes more critical. Care of the patient with CP has shifted toward an increased emphasis on improved upper extremity use.

DIAGNOSIS

CP is most commonly diagnosed at around 1 year of age due to delayed development of normal pinch motor milestones. Normal children develop two-handed activity and bilateral grasp, and progress from two-handed manipulation of objects to one hand at the age of 18 to 24 months. Early hand dominance is often a presenting sign in children with CP. In this scenario, a complete neurologic evaluation is necessary, including evaluation of their lower extremities, before a diagnosis of CP can be made.

CP is a disorder of the CNS that manifests itself in peripheral motor dysfunction and joint malpositioning. In spastic hemiplegia due to CP, the most common peripheral manifestations in the upper limb are shoulder internal rotation, elbow flexion, forearm pronation, wrist flexion/ulnar deviation, finger clenching (flexor spasticity), swan-necking, and thumb-in-palm deformity, as shown in Figure 72-1. Increased muscle spasticity causes muscle imbalance across joints, which initially leads to impaired function and eventually causes joint contractures with skeletal deformity. The typical elbow deformity of CP is elbow flexion and forearm pronation. Occasionally, it results in posterior dislocation of the radial head,³² which requires no treatment unless in adult life it results in a painful bursa; then the radial head may be excised. Flexion-supination contractures of the elbow can occur but are rare in CP.

FIGURE 72-1 Typical posturing of a spastic upper extremity in a patient with right hemiplegia due to cerebral palsy. The elbow is flexed, with forearm pronation, wrist flexion and ulnar deviation, and thumb-in-palm deformity

CLINICAL ASSESSMENT

Assessment of the patient with spastic CP starts with the history and physical examination. Because CP is associated with low birth weight and prematurity, associated medical problems should be noted, particularly seizures and mental retardation, which are indicators of more global CNS involvement.

Physical examination includes assessment of passive range of motion, active range of motion, muscle tone/control, and overall function of the limb (including hand function assessment). The limb is first examined for passive range of motion of the shoulder, elbow, forearm, wrist, and hand, evaluating for joint and muscle contractures. Even if only the elbow is to be treated, the shoulder, forearm, wrist, and hand need to be assessed because they are essential for the individual to effectively use the upper limb. Muscle tone is noted through the passive evaluation of joint mobility. Passive range of motion needs to be done slowly to overcome muscle spasticity with gentle sustained resistance. Assessment for muscle and joint contracture by passive mobility of the joint and passive stretch of the muscle is performed. The tightness and contracture of some of the muscles around the elbow can be easily palpated, particularly the biceps, brachialis, brachioradialis, and pronator teres.

Active range of motion is assessed next, including specific muscle testing for voluntary motor control, particularly of elbow flexion/extension as well as pronation/supination. Overall use of the upper extremity should be characterized both from history obtained from the parents as well as by direct physician observation. The dynamic positioning of the shoulder, elbow, forearm, wrist, fingers, and thumb are noted, particularly for grasp and release, as well as pinch function. Age-appropriate tasks or toys that require two-handed use are helpful in this assessment.

DEFINITION OF GOALS

Functional tasks that should be tested in every child are dressing, toileting, feeding, two-handed assisted work, grasp and release, and pinch. The functional goals for the limb should be established so that it can be determined whether the anticipated function is being accomplished by the patient. Goals for elbow surgery are different for a highly functioning hemiplegic versus a lower functioning quadriplegic. In a higher functioning child, common goals for elbow surgery include improved arm swing with gait, improved positioning of the hand in space, and improved cosmesis. For the lower functioning child or adolescent patient, common goals are decreased elbow contracture for better joint positioning and better hygiene.

In the past, sensory deficiencies of the hand were believed to be a contraindication to surgery in CP. If tested carefully, sensory deficiencies are present in nearly all children with CP.⁴² Several recent studies have shown that impaired sensation is not a contraindication to surgical intervention in the patient with CP.^6,^8,⁴² Appropriate consultation or multispecialty approach to care should be considered before considering surgical intervention. Several alternatives to surgical intervention exist and should be considered. Exploration of the treatment pros and cons may require discussions that include the rehabilitation physicians, neurologists, and neurosurgeons to adequately explore the options of tone reducing medications (diazepam [Valium], baclofen), tone-reducing injections (botulinum toxin, phenol), tone-reducing neurosurgery interventions (selective dorsal rhizotomy), or therapy interventions (splinting, stretching programs). At many institutions, a spasticity management team of specialists is involved with patient evaluation for tone-reducing interventions, and helps guide the orthopedic surgeon as to other treatment alternatives.

TRAUMATIC BRAIN INJURY

Most often, brain damage acquired in childhood is the result of trauma. The associated spasticity usually does not reach its maximum point until 1 to 2 months after the incident; then muscle tone may gradually decrease during the next 2 years.^22,²³

Irreversible surgical procedures should not be performed in children with acquired brain damage in the first 2 years after the insult. During this period, serial casting or splinting can be combined with botulinum toxin or phenol injections to deal with elbows with significant flexor tone. Another problem in children with acquired brain injury is heterotopic bone formation, usually about the anterior aspect of the elbow.³⁵ Unlike adults, most children eventually resorb the heterotopic bone. Therefore, we recommend gentle motion and re-evaluation at least 6 months before any attempt is made at excision.

STROKE AND HEAD TRAUMA IN ADULTS

Stroke and head trauma produce permanent impairment in approximately 3 million adults in the United States. Abnormal elbow function due to spasticity and loss of motor control is a common disability. The surgeon treating these conditions must be fully cognizant of the complex rehabilitation process after CNS illness, particularly hand rehabilitation. Surgery is undertaken only after careful assessment of the many factors that determine the patient’s potential to use the limb.³

Cerebral vascular accidents commonly involve the middle cerebral artery or its branches in the region of the cerebral cortex supplying the upper extremity. Consequently, the upper extremity usually is affected more frequently–and more severely–than the lower extremity. Elbow flexion contractures are nearly always preventable in stroke patients if standard preventive measures are instituted early. In contrast, head injury is often associated with excessive elbow flexor tone because of decerebrate or decorticates rigidity. The spasticity may be so severe that nonoperative measures alone may not prevent elbow deformity.

Substantial neurologic recovery generally follows strokes and head injury. In stroke patients, most neurologic recovery is completed in the first 6 months; in head trauma, patients’ substantial recovery extends over the first year and a half.¹⁷ Definitive surgical procedures to improve function are deferred until after the patient’s neurologic condition has stabilized and he or she has learned to cope with the disability and has received appropriate nonoperative therapy.

Prevention of elbow muscle and joint contractures is paramount. Nonoperative therapy should include passive range of motion, splints, and serial casts; if progressive elbow flexion deformity develops before neurologic recovery, then botulinum toxin of the biceps and brachialis or phenol injection of the musculocutaneous nerve is performed.¹³ Elbow flexion contracture due to spasticity is the most common problem that ultimately requires surgical attention, because it commonly affects patients with nonfunctional hands. Surgery is indicated to correct contracture deformities that interfere with hygiene or cause pain; rarely, it is used to improve cosmesis. Operative intervention is usually deferred until neurologic recovery is complete, which is in 6 to 18 months.

PREOPERATIVE EVALUATION

After a thorough medical history investigating the etiology of the elbow spasticity and a documentation of related medical conditions, a physical examination is documented. Range of motion is determined by quickly and slowly extending the elbow. Quick stretch excites the velocity-sensitive components of the muscle spindle and may elicit clonus if spasticity is severe. Consequently, a greater range of extension often can be obtained by slow extension (often over 1 or 2 minutes) with the patient relaxed. Even with excellent patient cooperation, definitive differentiation of muscle tone versus muscle contracture is difficult. Ultimately, spasticity can be differentiated from fixed contracture only by preoperative nerve block or examination under general anesthesia.

Dynamic electromyography ^19,^38,⁴¹ is becoming increasingly useful because it enables surgeons to determine more precisely which flexor muscles are responsible for a deformity (Fig. 72-2) or whether surgical ablation of a given muscle will be effective.²⁶ Kozin et al reports its use in distinguishing spasticity patterns of the brachioradialis, biceps, and brachialis. This information is particularly valuable for patients with functional elbow motion because it enables the surgeon to release or lengthen only the muscles most involved and to preserve those that are less involved. Slow and fast volitional elbow flexion and extension are assessed. Attempts to move the elbow rapidly enhance an abnormal flexor response.

FIGURE 72-2 Dynamic electromyogram of head-injured patient with spasticity during slow elbow extension-flexion-extension-flexion cycle. The triceps displays normal bursts of activity during the extension phase. The brachialis is also normally active in flexion. Note that both the long and the short heads of the biceps are inappropriately active during attempted elbow extension, indicating obstructive tone

Anterior and posterior radiographs of the elbow are taken before any surgical procedure. Arthritis and other conditions common in the adult patients may be responsible for intrinsic joint restriction and can decrease the probability of a successful surgical outcome. For patients with traumatic brain injury, skeletal trauma to the elbow needs assessment. Presence of heterotopic ossification should also be assessed as this is a known complication of head injury.

Last, preoperative evaluation always includes a detailed assessment by a therapist and/or cooperation with a spasticity management team: evaluation of motor and perceptual function of the elbow, hand, and shoulder and examination of cognitive, vocational, and social factors that are important determinants of arm function and treatment goals.

TREATMENT OPTIONS

Treatment of the spastic elbow includes several options. If the deformity is not fixed, and the major goal is reduced muscle tone to improve joint position and function, the elbow flexor tone can be diminished by several methods. Tone-reducing medications (Valium, baclofen) would be indicated if the overall global tone is severely affected; consultation with a neurologist or rehabilitation specialist to initiate this treatment would be indicated. Mild elbow contractures can be diminished by range-of-motion stretches and elbow splinting; referral to a physical or occupational therapist to initiate this treatment would be indicated.¹

Tone reduction specifically localized to the elbow can be achieved through the use of botulinum toxin injections, and phenol injections; a more permanent tone reduction can be achieved with neurectomy or muscle-lengthening procedures. Muscle-lengthening procedures are the most common surgical procedure performed in the elbow for CP. In order to reduce the flexion posturing of the elbow, lengthening of the biceps and brachialis would be indicated. If the flexion posturing includes pronation deformity of the forearm with wrist flexion and finger flexion posturing, then a flexor pronator slide would be indicated.

If the deformity is fixed, and the contracture of the elbow is long standing, a biceps tenotomy, brachialis lengthening, and brachioradialis release may be indicated with the goal of achieving improved, but not complete, elbow extension. Muscle and elbow joint releases will be limited by the length of the neurovascular bundle; care to avoid neurovascular injury is paramount. If the muscle release is inadequate, a distal humeral extension osteotomy can be performed.

As shown in Figure 72-3, timing of surgical intervention is critical and depends on the presenting diagnosis. Because spasticity develops as a consequence of an upper motor neuron dysfunction in the CNS, it is imperative that neurologic recovery is complete before definitive surgical interventions are performed. Botulinum toxin injections and phenol injections are often recommended as temporary measures during neurologic return, or as interventions in the growing child with worsening contractures. Definitive surgical procedures include musculocutaneous neurectomy or elbow muscle lengthenings of the biceps, brachialis, or brachioradialis muscles or flexor pronator slide. Heterotopic ossification of the elbow can occur with traumatic brain injury or stroke, and is discussed as well.

FIGURE 72-3 Decision algorithm for treatment of the spastic elbow

BOTULINUM TOXIN INJECTIONS

Botulinum toxins (Botox, Allergan Pharmaceuticals, Irvine, CA) are protein products of Clostridium botulinum, and are potent neuromuscular paralyzing agents. Botulinum toxin type A is a related protein that can be used therapeutically in minute doses to block the release of acetylcholine to functionally denervate portions of the muscle causing a localized, dose-related weakness, with little or no systemic absorption of the toxin.^30,⁴⁰ Botulinum toxin has been used to control tone in upper extremities.⁵ It gives temporary benefits that may help therapists and may be most beneficial to head-injured children.³⁸

TECHNIQUE

Clinical application for decreasing elbow tone spasticity has been described using doses of 5 to 10 units/kg for all muscles injected, using 3 to 5 units/kg for the biceps and brachialis.⁴⁴ Dilution of the medication in 1 to 5 mL of normal saline helps spread the medication through the muscle belly. Most commonly, a neuromuscular stimulator is used to localize the injection close to motor endplates.²⁵

RESULTS

For patients with more focal muscle tone imbalance, botulinum toxin type A injections has been shown to be effective in reducing spasticity in the muscles injected and in improving elbow function. The effects of the injection last approximately 4–6 months. During this period, assessment of the antagonist muscles can be made and possible surgical benefits can be assessed. In addition, antagonist muscles can be strengthened and spastic muscles can be stretched with the benefits lasting beyond the direct effects of the medication. For the mildly involved child, treatment with Botox injections may obviate the need for surgical intervention.

Wallen et al ⁴⁴ reported improved goals (dressing, arm at side), decreased elbow tone, and good parent/patient satisfaction in 16 children, with a return to baseline by 6 months in most measures. Chen⁴ measured decreased elbow flexor spasticity within 2 weeks after injection. A recent meta-analysis⁴⁵ of 12 studies (three randomized controlled and nine uncontrolled) showed that, although some reports measured decreased spasticity, increased range of motion, or increased functional activities, there was either insufficient evidence or insufficient tools to predictably measure reduced spasticity or increased range of motion or improved upper limb function after treatment with botulinum toxin type A injections.

PHENOL INJECTIONS

Acquired spasticity may be effectively controlled by open or percutaneous phenol nerve injections. The purpose of phenol injection is to provide a temporary reduction in spasticity, in order to allow improved limb function and rehabilitation, as well as to prevent joint contracture. Open nerve injections are selected over percutaneous injections if the nerve contains both sensory and motor components. Open technique allows for isolation of the motor branches for injection, and prevents postblock dysasthesias or loss of sensation.

In patients with traumatic brain injury or stroke, phenol is a common treatment used. Because the effects of the block are not permanent, no functional loss will occur if central neurologic recovery is complete. If central recovery is incomplete and spasticity recurs, then definitive surgery (neurectomy or tendon lengthening) may be safely performed at that point.

RESULTS

Garland et al ¹³ described 13 phenol injections in 12 patients for treatment of elbow spasticity at 4.5 months after closed head trauma. The preinjection elbow flexion contractures averaging 55 degrees improved on average 43 degrees when combined with serial casting; all elbows had less than a 20-degree contracture. After neurologic recovery was complete, two elbows went on to other elbow surgical procedures for spasticity.

Keenan et al ²¹ reported on 23 elbows in 17 brain-injured adults treated with percutaneous phenol blocks of the musculocutaneous nerve to control elbow spasticity. Ninety-three percent of patients responded with an improvement of resting elbow flexion from 120 degrees of flexion to 69 degrees of flexion. The mean duration of the block was 5 months.

NEURECTOMY

Musculocutaneous neurectomy is performed only in nonfunctional upper extremities with an elbow flexion contracture interfering with positioning or hygiene. Even when minimal or no fixed myostatic or joint contracture is present, spasticity may force the elbow into a flexed posture that interferes with function. When hemiplegics walk, it is common for the elbow to assume a flexed posture and it may bounce up and down because of clonus. The patient may purposely walk slowly to decrease clonus. Musculocutaneous neurectomy improves cosmesis and eliminates clonus.¹⁶ After musculocutaneous neurectomy, the loss of elbow flexion strength is not important, because most stroke patients with excessive elbow flexion have nonfunctional hands.

Because the brachioradialis is innervated by the radial nerve, which is left intact, some elbow flexion persists after surgery if this muscle was active preoperatively, and the loss of musculocutaneous sensation is not bothersome. In a patient who has no brachioradialis control or spasticity, this procedure should not be performed, because musculocutaneous neurectomy leaves a completely flail elbow because a neurectomy irreversibly eliminates all motor input to the biceps and brachialis muscles. If the patient has effective control of the brachioradialis or flexor pronator muscles, these muscles may continue to provide elbow flexion.

If elbow contracture exists due to tone alone (usually less than 30 degrees), then partial neurectomy would most commonly improve elbow positioning. If contracture exists in the muscle or joint, then additional serial casting or muscle-lengthening procedures may be necessary to improve elbow extension. A lidocaine (Xylocaine) block of the musculocutaneous nerve along the medial proximal border of the biceps is helpful for separating the effects of flexor tone from those of contracture. Contracture should be expected to ensue when the spastic posture has been present for years. The lidocaine block also predicts brachioradialis elbow flexion capability after neurectomy.

TECHNIQUE

A longitudinal incision is made beginning at the insertion of the pectoralis major muscle in the interval between the biceps (short head) and the coracobrachialis, as shown in Figure 72-4. The biceps and lateral cord of the brachial plexus are located. The musculocutaneous nerve arises from the lateral cord and needs to be identified separate from the median nerve. The nerve is identified before it enters the biceps and confirmed by nerve stimulation. A 1-cm section of the nerve is excised. The wound is closed. The elbow is then splinted in maximum extension.¹⁶

FIGURE 72-4 A, Axillary exposure provides access to the musculocutaneous nerve, which usually branches from the brachial plexus high in the axilla and is isolated between the biceps and the coracobrachialis (B). The nerve may be injected with phenol or surgically released, as desired.

(From Garland, D. E., Lucie, R. S., and Waters, R. L.: Current uses of open phenol nerve block for adult acquired spasticity. Clin. Orthop. Relat. Res. 165:217, 1982 [B redrawn].)

RESULTS

A large series of 75 elbows in 52 patients treated at an average age of 9.5 years old using a selective motor fasciculotomy of the musculocutaneous nerve reports follow-up at 1.5 years.³⁴ Total relief of spasticity was achieved in 63% of patients and partial relief in 37%. The authors recommend the procedure as safe, effective, and long lasting.

Garland et al ¹⁶ report on 30 musculocutaneous neurectomies in 29 patients with a nonfunctional upper extremity due to cerbrovascular accident (59%) or head injury (24%). The goals of the surgery were to improve personal hygiene, ambulation (arm swing), and appearance. Patients with a 30-degree contracture preoperatively did not require postoperative casting; patients with a 30 to 75 degree flexion contracture preoperatively required postoperative casting; and patients with greater than 75-degree flexion contracture preoperatively required concomitant muscle releases with postoperative casting. Twenty-eight patients were successfully treated. Other studies have reported similar results.^27,³⁷

BICEPS-BRACHIALIS LENGTHENING

Biceps-brachialis lengthening is the most common surgical procedure used in the treatment of elbow spasticity. Goals of the surgery are to improve passive and active elbow extension. In the highly functional patient with 30- to 60-degree contracture, this procedure improves gait by allowing the arm to come to the side for swing, improves ease of dressing, and improves cosmesis. In the low-functioning patient with greater than 60 degree contracture, this procedure is done primarily for hygiene; in this case, achievement of full extension is not necessary.²⁴ When deformity is long standing and myostatic contracture considerable, biceps tenotomy can be performed.

TECHNIQUE

Mital ²⁹ performs biceps-brachialis lengthenings through a curved antecubital approach (Fig. 72-5). The lacertus fibrosus is excised, and Z-plasty of the biceps tendon and release of the brachialis aponeurosis are performed. Most commonly, a correction of 30 to 40 degrees is obtained. If near–full extension is achieved, as shown in Figure 72-6, then no further release is necessary. Further correction can be obtained by release of the origin of the brachioradialis, and/or partial myotomy of the brachialis. In long-standing contractures of greater than 60 degrees, further elbow extension is blocked by contracture of the neurovascular structures and skin. Excessive tension on the neurovascular elements is unnecessary and can lead to vascular compromise. It is not usually necessary to release the anterior capsule. If this procedure is performed on nonfunctional limbs, full extension is not necessary and surgery in combination with postoperative serial casting provides adequate correction. A period of 4 weeks of postoperative immobilization, followed by bivalved elbow splinting, is recommended.

FIGURE 72-5 Diagrams of the sequential steps of the elbow flexor Mital lengthening procedure. A, The initial incision. B, The exposure of the tendon of the biceps, and the excision of the lacertus fibrosus. C, Third step of the elbow flexor-lengthening procedure: the Z-lengthening of the biceps tendon. D, The incision of the aponeurotic fibers covering the brachialis.

(Redrawn from Mital, M. A.: Lengthening of the elbow flexors in cerebral palsy. J. Bone Joint Surg. 61A:515, 1979.)

FIGURE 72-6 Clinical case of the sequential steps of the elbow flexor lengthening procedure, the most common procedure for elbow spasticity. A, A curvilinear antecubital incision is made with a sterile tourniquet in place, with the arm positioned on an arm board. B, The lateral antebrachial cutaneous nerve is identified and protected as it courses laterally from under the biceps tendon. C, After the lacertus fibrosis has been excised, the biceps tendon is cut in a Z-lengthening manner with each end of the tendon tagged with suture. D, The fascial investment of the brachialis muscle is incision several times transversely. E, After the tourniquet has been deflated, the biceps tendons are woven back into each other in a lengthened position. The wound is then closed and the patient’s elbow is splinted in full extension.

RESULTS

Mital ²⁹ has the largest series in the literature, reporting on 32 elbows in 26 patients. Preoperative flexion contracture averaged 48 degrees (range 30 to 60 degrees); postoperative flexion contracture averaged 10 degrees (range 0 to 15 degrees). Average age at the time of surgery was 12 (range 6 to 19 years). Eleven of his patients were quadriplegic, and 15 were hemiplegic. He describes preoperative complaints of excessive dynamic elbow flexion that occurred with excitement or gait, and was a source of frustration and embarrassment. He describes improved gait, improved positioning of the arm, and improved cosmesis in these highly functioning patients. Koman²⁴ describes use of this procedure for more severely involved patients with greater than a 60 degree elbow flexion contracture without specific results reported.

Manske ²⁸ describes a similar procedure with incision of the lacertus fibrosis, lengthening of the brachialis fascia, and stripping of the biceps tendon (without Z-lengthening). For 42 elbows in 40 patients, he reports improved dynamic posturing of the elbow from 104 degrees preoperatively to 55 degrees postoperatively. Functional use, as well as aesthetics of the limb, was improved.

FLEXOR-PRONATOR SLIDE

Although flexor pronator slide does provide improved elbow extension, the primary indication for this procedure is for treatment of the forearm, wrist, and hand. If the patient has elbow flexion combined with forearm pronation, wrist flexion, and difficulty with simultaneous wrist and finger extension, then the procedure may be indicated. Volitional control of wrist and finger extension, which is diminished due to overpowering wrist and finger flexor tone, can be improved by this operation. Preoperatively, assessment of the balance of tone may be assisted by diagnostic botulinum toxin injections into the flexor pronator wad.

TECHNIQUE

The origin of the pronator-flexor group is released through a medial incision, extending from the medial epicondyle to the proximal forearm. The ulnar and median nerves are identified and protected, and all the structures between them are released, including the pronator teres, flexor carpi radialis and ulnaris, and the flexor digitorum superficialis and profundus. The muscle origins are allowed to slide distally from the medial epicondyle, ulna, and radius. During the release, the medial collateral ligament of the elbow is identified deep to the muscle origin and left intact; the joint capsule is not violated. The slide of the muscles’ common origin should allow improved passive wrist and finger extension primarily, with secondary improved elbow extension. A postoperative long arm splint or cast is used for 4 weeks, holding the elbow in maximum extension, the forearm in supination, and the wrist and fingers in extension. With spasticity in the cast, the muscle length tension heals in an optimum position. After casting, orthoses are used as necessary.

RESULTS

Pinzur ³¹ reports on the use of the flexor pronator slide in combination with a Z-lengthening of the flexor pollicus longus tendon for treatment of the spastic hand in the adult after stroke. All patients improved two functional levels following the surgery. White⁴⁶ described the use of the flexor pronator slide in 27 patients, using a concomitant wrist arthrodesis in 12 patients. No comment was made regarding effect on elbow function; wrist and hand function was good in 10, fair in 11, and poor in 11. Poor results were seen in the patients with poor drive, poor intelligence, and poor motor control. Inglis et al¹⁸ reported on 18 patients treated at an average age of 19 (range 12 to 45 years old) for severe spastic contractures of the wrist and hand that were not actively or passively correctable. At an average of 17 months after surgery, there were no recurrences of flexion deformities of the wrist and hand. The patients with mild contractures of the elbow were noted to be “improved,” and in the six patients with severe elbow contractures, release of the brachialis fascia was performed concomitantly. Use of the flexor pronator slide is focused primarily on treatment of the hand spastic dysfunction, with gains in elbow spasticity seen only as a secondary effect.

HETEROTOPIC OSSIFICATION

Heterotopic ossification of the elbow, a severe complication that occurs in about 3% of head-injured patients, is discussed in detail in Chapter 31, but is also relevant in the context of this chapter. It most commonly occurs when hypertonus at the elbow is severe because of rigidity from decorticate or decerebrate posturing or spastic hemiplegia (Fig. 72-7). In general, heterotopic ossification is apparent within the first 6 months after head trauma (peak occurrence 2 months). The typical stroke patient infrequently develops heterotopic ossification. With head injury, the complication occurs more often posterior than anterior.¹¹

FIGURE 72-7 Decerebrate rigidity may be associated with myositis ossificans in the anterior muscles (A) but even more often in the posterior aspect of the elbow (B).

(From Garland, D. E., Blum, C. E., and Waters, R. L.: Periarticular heterotopic ossification in head-injured adults. J. Bone Joint Surg. 62A:143, 1980.)

The incidence of traumatic heterotopic ossification in combined head and elbow injuries is 90%.¹⁴ Heterotopic ossification most often affects the collateral ligaments but can form in any planes about the elbow. Bone formation in the ulnar collateral ligament may contribute to an acute ulnar palsy from the localized swelling or delayed ulnar palsy resulting from long-standing pressure.²⁰

Heterotopic ossification is heralded by swelling, pain, and limitation of motion at the elbow. Evidence of heterotopic ossification on bone scans is apparent 2 to 3 weeks before radiographic evidence of calcification appears. Alkaline phosphatase may not be elevated if only a small amount of new bone is present. Muscle hypertonus exerts continuous forces across the inflamed joint, which intensifies the pain. Pain, in turn, increases spasticity, completing the vicious circle. If the patient’s neurologic condition improves rapidly, the amount of heterotopic ossification is lessened, and no significant impairment may result if an adequate range of elbow motion is maintained. On the other hand, extremity function may be affected if elbow motion becomes severely restricted or ankylosis develops, even if neurologic recovery has occurred. Even in a nonfunctional arm, hygiene of the elbow flexor crease and limb positioning are difficult in a patient with severe limb flexion deformity and ankylosis.

Treatment of heterotopic ossification begins with prompt recognition of the condition. Joint motion is preserved by range-of-motion exercises. Movement should be slow to minimize pain. Elbow splints are useful to position the elbow in maximal extension. Diphosphonate therapy is controversial. Indocin, for 3 months, may be used alone or in combination with diphosphonates.⁹ Oral spasmolytic agents or phenol injection of the musculocutaneous nerve may help to reduce muscle tone in the biceps and brachialis muscles. Temporary reduction of elbow flexor tone permits the therapist to perform range-of-motion exercises more easily to maintain elbow extension. Forceful manipulation of the elbow under anesthesia also may help to maintain or increase elbow range.¹⁵

Because heterotopic ossification is so prevalent with combined head and elbow injuries, some type of prophylaxis seems warranted. This type of heterotopic ossification is not related to the severity of the head injury, and joint spasticity may not be present. Resection of heterotopic ossification is performed after the bone is skeletally mature.¹⁰^–¹² ³⁵ Active motion is essential to maintaining joint range after surgery. Indocin or radiation may be used for prophylaxis.⁹