In utero, the arm bud appears 26 days after fertilization and 24 hours before the appearance of the leg bud. Growth proceeds in a proximal-to-distal manner. Development is guided by the apical ectodermal ridge via fibroblast growth factors, inducing the mesoderm to condense and differentiate (3). The zone of polarizing activity guides radioulnar differentiation and development of the limb, mediated by the sonic hedgehog protein and other growth factors. Similarly, the Wnt signaling center influences dorsal-volar development of the hand. The upper limb anlage is initially continuous and extends to a hand paddle by day 31. The digital rays develop by day 36 with fissuring of the hand paddle, initially in the central rays, followed by the border digits. Mesenchymal differentiation also begins in a proximal-to-distal manner with chondrification, enchondral ossification, joint formation, and muscle and vascular development. Both joint formation and digital separation occur via apoptosis, or programmed cell death. The entire process is complete by 8 weeks after fertilization (4). Other major organ systems develop at the same time as the upper limb, which explains the associated cardiac, craniofacial, musculoskeletal, and renal anomalies that can occur with upper limb differences.

Homeobox, or HOX, genes regulate the development of the limb (5). Their genetic expression controls the timing and extent of growth by regulating mesenchymal cells. At present, the understanding of the genetic basis of limb development, and therefore of the occurrence of congenital anomalies, is expanding rapidly (6, 7, 8, 9, 10, 11 and 12). For example, a mutation at the HOXD13 site has been identified as a cause of polysyndactyly (13). A further understanding of the role of genetics in limb development may revolutionize the treatment of congenital deficiencies.

Congenital anomalies occur in approximately 6% to 7% of live births, with 1% being multiple anomalies. It has been estimated that between 1 in 531 and 1 in 626 live births involve upper extremity anomalies (14, 15). Only 1% to 2% of these congenital differences are the result of chromosomal abnormalities.
However, 75% of 233 spontaneous abortions studied were noted to have an abnormal karyotype, with 18% having a morphologic defect and normal karyotype (16). At present, only a small percentage of these are known to be caused by defined genetic events. In most cases, the cause of the congenital difference is unknown, but expanding genetic information provides optimism for increased knowledge in the near future.

There is no perfect classification system for congenital differences of the hand and upper limb. The currently accepted classification system for congenital differences was proposed by Swanson (17) and revised by the Congenital Anomalies Committee of the International Federation of Societies for Surgery of the Hand (18, 19). This classification is based on embryologic or developmental failure and defines deficiencies as terminal or intercalary, with a subclassification into longitudinal and transverse deficiencies. The subcategories are as follows: (a) failure of formation of parts, (b) failure of differentiation of parts, (c) duplication, (d) overgrowth, (e) undergrowth, (f) constriction band syndrome, and (g) generalized skeletal abnormalities. However, there have been reports of inconsistencies in classifying congenital anomalies of the upper limb by this system (20). A more descriptive method has been shown to be valid (19, 21).

This chapter focuses on the major anomalies in each classification group but presents them by anatomic region. Caring for the child with congenital differences involves more than surgical skill. From the time at which the diagnosis is made, these children may potentially be viewed by their parents, family, and society as being impaired; if this premise is left unchallenged, these patients may view themselves the same way (22, 23). It is critical that the treating surgeon helps provide the emotional support and caring that allow the parents and the child to appropriately grieve the loss of a normal hand (24). It is helpful to provide them with in-depth knowledge of the cause and treatment options (25). This process starts with the initial clinical consultation and continues throughout the growth and development of the child into an independent, self-reliant adult (26). Support groups are useful for many of these children and their families.

The children who have normal central nervous systems and cognitive abilities will not be impaired. They will merely develop their skills in a “different” way from their peers. They may need the help of skilled and caring parents, siblings, therapists, teachers, coaches, prosthetists, and surgeons in order to achieve their goals and dreams. Being part of helping these children grow into unique and independent adults is exciting and rewarding for the pediatric orthopaedic surgeon.

Children with cerebral palsy frequently have difficulty with hand function, and often the most noticeable associated deformity is of the thumb (Figs. 22-5, 22-6, 22-7 and 22-8). Several authors have discussed in detail the indications for correction of such deformities (38, 72, 73). Most authors have stressed the importance of the preoperative evaluation of outcome, with assessment of voluntary control, sensation, cognition, and the ability to cooperate with a postoperative program, these being the most important factors to consider in the assessment of outcome.

House et al. (38) have classified the deformities by an assessment of the thumb’s function rather than by its static position.

Brachial plexus birth palsy is rare, with an incidence between 0.1% and 0.4% of live births (76, 77 and 78). Fortunately, most infants with minor birth palsies recover fully. These are the infants who initiate recovery of all muscle groups in the first 1 to 2 months of life. However, permanent impairment does occur in infants who do not initiate antigravity motor recovery before 5 to 6 months of life (79, 80, 81, 82 and 83). Most infants have involvement of the upper trunk (C5-C6, causing Erb palsy and, often, additional involvement of C7). Less often, the entire plexus (C5-T1) is affected. In rare instances, the lower trunk (C7-T1, causing Klumpke palsy) is most affected.

Perinatal risk factors include infants who are large for gestational age; prolonged labor; previous births with brachial plexopathy; difficult delivery, including extraction techniques; and fetal distress. Shoulder dystocia is the mechanical factor that leads to an upper trunk lesion in the difficult vertex delivery. Difficult arm extraction in a breech delivery can result in an avulsion injury of the upper trunk (31). The degree of impairment is related to the level and magnitude of injury to the plexus. Neural injury is defined by the type (stretch, rupture, avulsion) and severity (Sunderland grades I to V). Prognosis
by natural history has been best defined by the spontaneous rate of recovery of muscle strength in the first 3 to 6 months of infancy. Gilbert and Tassin (83) described the recovery of antigravity biceps function in infancy as a predictor of the outcome of spontaneous recovery. This finding was confirmed in a similar study by Waters (82). These studies demonstrated that infants who did not recover biceps function by 3 months of life were not normal after 2 years of age. Gilbert et al. recommend microsurgical reconstruction of the plexus in the first 3 to 6 months of life for infants who fail to recover biceps function (83, 84 and 85)(61). Michelow et al. (86) noted that return of biceps function alone had a 12% error rate in predicting outcome, as defined by long-term antigravity muscle strength. By using elbow flexion, elbow extension, wrist extension, finger extension, and thumb extension (the Toronto scale), their error rate for predicting outcome decreased to 5%. In this system, each muscle group is scored as 0 (no motion), 1 (motion present but limited), or 2 (normal motion), for a maximum score of 12. A score of <3.5 predicted a poor long-term outcome without microsurgery. In all studies, the presence of Horner syndrome, total plexus involvement, and failure of return of function by 3 to 6 months of life portend a poor long-term outcome.

Clinical examination of an infant for motor-sensory function can be challenging. It is important to distinguish true paralysis from the pseudoparalysis that comes with a neonatal clavicle fracture, humeral fracture, or septic shoulder. There can be clinical overlap because fractures also occur in infants with shoulder dystocia and infantile brachial plexopathy. Plain radiographs will identify the infant with clavicle and humeral fractures. In the neonate, these fractures heal within 10 to 21 days. If restriction in range of motion persists after 1 month, there is most likely a concomitant brachial plexopathy. In the rare infant with a septic shoulder, there will be evidence of systemic illness (altered vital signs, change in appetite, toxicity), marked irritability with glenohumeral range of motion, and abnormal white blood cell count (87). If there is doubt, ultrasonography will reveal the effusion, and arthrocentesis will be confirmatory.

The pupils should be assessed for Horner syndrome. Motor examination is limited to observation of spontaneous activity and stimulated movement by primitive reflexes in the infant. The Moro startle reflex and the asymmetric tonic neck reflex can elicit upper trunk movement in infants in the first 6 months of life. Classification of nerve injury in the ambulatory child has included physical assessment according to the Mallet system. The modified Mallet system classifies uppertrunk function by grading hand-to-mouth, hand-to-neck, and hand-on-spine activity, global abduction, and global external rotation from 0 (no function) to V (normal function). Grades II, III, and IV are illustrated (Fig. 22-10). The Hospital for Sick Children Active Movement Scale is also utilized to define the degree of motor recovery, grades I through IV being gravity-assisted and grades V through VII being against gravity. These classification systems have been shown to be reliable in intra- and interobserver analysis (88).

Radiography can demonstrate an associated fracture of the clavicle or proximal humerus. Radiographic assessment of the severity of brachial plexus injury may be attempted using
myelography, combined computed tomography (CT) scan and myelography, and magnetic resonance imaging (MRI). Kawai et al. (89) compared the results of all three techniques with operative findings. MRI and combined myelography and CT scan were more reliable than myelography alone. The presence of large diverticulae and meningoceles was indicative of root avulsion. Small diverticulae were diagnostic only 60% of the time. Electrodiagnostic studies, with electromyography and nerve conduction studies, are diagnostic of avulsion if there is no reinnervation after 3 months of age. However, the presence of reinnervation does not indicate the long-term quality of muscle recovery.

Children with Sprengel deformity (128) often present with a decreased neck line, limited motion about the shoulder, or both. This is secondary to the embryonic failure of one, or sometimes both, scapulae to descend in utero. The abnormal elevation is in conjunction with hyperplasia and abnormal alignment of the scapula. Most often, the scapula is small and shaped like an equilateral triangle rather than having a long medial border. The scapula in Sprengel deformity usually has abnormal anterior bending of the superior pole into the convexity of the upper thoracic region. There is often limited forward flexion and abduction of the shoulder because of lack of normal scapulothoracic motion and malpositioning of the glenoid. In up to 50% of cases, there may be an associated omovertebral bar, which consists of a fibrous, cartilaginous, or bony connection between the superior medial angle of the scapula and the cervical spine (129). Frequently, there is associated abnormal regional anatomy including scoliosis, spina bifida, clavicular abnormalities, rib anomalies, and Klippel-Feil syndrome, among others (130, 131). Systemic abnormalities include renal and pulmonary disorders. In 10% to 30% of the cases, the condition is bilateral.

A classification by Cavendish (130) grades the severity of deformity in a rudimentary way: grade I is mild, with level glenohumeral joints and no deformity visible when the patient is dressed; grade 2 has level glenohumeral joints, with a lump in the neck region with the patient dressed; grade 3 is a moderate deformity with 2 to 5 cm of shoulder elevation; and grade 4 is severe, with elevation of the scapula to the vicinity of the occiput. The more severe the deformity, the more likely there are to be limitations
of motion and function and associated regional anatomic anomalies. Surgery is indicated in children with severe aesthetic and functional limitations. Surgery does not correct the scapular hypoplasia but is indicated for improving shoulder motion by restoring more normal positioning of the scapula and the glenoid. This often consists of excising any omovertebral connections and surgically derotating and caudally relocating the scapula. Most of the procedures that are described include extraperiosteal resection of the superior pole of the scapula (130, 132). Subperiosteal resection is associated with a high rate of recurrence (133, 134). In addition to functional indications for surgery, most patients and families welcome the improvement in the appearance of the neck line.

In the mild deformities, extraperiosteal excision of the superior pole of the scapula and any omovertebral connections alone may be satisfactory treatment. In the moderate and severe deformities, the scapula is also derotated and moved more distally in order to bring the glenoid into a more vertical orientation. The purpose of surgery is to improve the neck contour along with shoulder motion and function. Indications for functional improvement have been cited for preoperative abduction <110 to 120 degrees (129, 135). Surgery is recommended most often in patients between 3 and 8 years of age (136, 137 and 138). Surgery after 8 years of age is associated with the highest risk of nerve impairment; clavicular osteotomy or morsellization is recommended in the older child in order to lessen the risk of brachial plexus impingement with scapular descent.

Surgical procedures for scapular descent have included the Woodward procedure (139), the Green procedure (140, 141), and a vertical scapular osteotomy (142). The Green procedure involves extraperiosteal detachment of the scapular insertion of the paraspinal muscles, and reattachment after the scapula has been moved distally with traction cables. Wilkinson and Campbell described a vertical scapular osteotomy in conjunction with a clavicular osteotomy in the older child for improving anterior release and scapular relocation and for lessening the risk of neurologic injury. The Woodward procedure moves the scapula distally by detachment and reattachment of the parascapular muscles at their origins on the spinal process. The modified Woodward procedure includes resection of the superior pole of the scapula in conjunction with surgical scapular descent and realignment. The results have been reported to have improved abduction in the range of 40 to 50 degrees (129, 143) and achieved a satisfactory aesthetic result. Hypertrophic scar formation, however, has been cited often as a complication.

Congenital high scapula, commonly known as Sprengel deformity, is not a common condition. It can be seen in all degrees of severity. As a result of the school-screening programs, we have seen numerous children with minor degrees of scapular elevation and smaller scapulae on one side. Minor degrees of high-riding scapulae need no treatment and are usually not associated with other developmental abnormalities around the shoulder. At the other end of the spectrum is the child diagnosed at birth or shortly thereafter. The physician seeing the infant or the small child should realize that the deformity usually becomes worse with growth. This can be difficult to judge when the child is between 4 and 8 years of age. However, 4 to 8 years is the ideal time for optimal correction. The condition develops during the 9th to 12th weeks of gestation; therefore, other organs, as well as those structures around the shoulder girdle, may be affected. An understanding of the pathologic anatomy is important for the correction of the deformity and for the avoidance of complications. The scapula is shorter in its vertical height than the opposite normal scapula and is more concave anteriorly to fit the convex shape of the superior aspect of the thoracic cage. In addition, the supraspinous portion of the scapula is usually tilted forward and its superior medial portion may be larger. The clavicle may also be higher and shorter, lacking its usual anterior convexity (136). In about one-third of the cases, an omovertebral bone connects the superior medial angle of the scapula to the posterior elements of the fourth and fifth cervical vertebrae. This may actually be bone, cartilage, or fibrous tissue. Finally, the muscles of the shoulder girdle are usually affected, and hypoplasia of the trapezius and rhomboids is the most common problem.

Two operations for the correction of Sprengel deformity have stood the test of time and are the most commonly used. The Green procedure (140, 144, 145 and 146) detaches the muscles from the scapula, whereas the Woodward procedure (139, 147) detaches the origins of the trapezius and rhomboids from the spinous processes (Figs. 22-14, 22-15, 22-16, 22-17, 22-18 and 22-19). We have had experience with both procedures and find the Woodward procedure to be easier (but not easy) and to produce the same results with a shorter period of hospitalization and lower morbidity. Surgery is expected to improve the cosmetic appearance and the function of the shoulder (129, 148).

One of the most important complications is radial nerve palsy resulting from compression of the brachial plexus between the clavicle and the first rib when the scapula is pulled down. This is more common in children aged 7 years or older and is relatively uncommon in children aged 3 to 4 years. Some authorities have advocated division or morcellation of the clavicle to prevent this complication (136, 149). This is an effective measure, but it is important to determine which patients require it because the incidence of radial nerve palsy is low (139, 140, 143, 150), especially in young children. This additional procedure may be reserved for affected children older than 8 years and for those younger children who have an unusually severe deformity. When nerve palsy is noted after the Woodward procedure, division of the clavicle can be done.

Woodward Repair of Sprengel Deformity (Figs. 22-14, 22-15, 22-16, 22-17, 22-18 and 22-19)

Congenital pseudarthrosis of the clavicle is an unusual condition of unknown etiology. Although the name often causes congenital pseudarthrosis of the clavicle to be confused with congenital pseudarthrosis of the tibia, there is no similarity in the etiology or the natural history of these conditions. The pathology of congenital pseudarthrosis of the clavicle, unlike that of the congenital pseudarthrosis of the tibia, is of two bone ends covered with cartilage and often encapsulated with synovial tissue and fluid. It is clear, however, that resection of the pseudarthrosis, bone graft, and internal fixation are necessary to obtain union (Figs. 22-20, 22-21, 22-22, 22-23 and 22-24) (151, 152, 153 and 154).

Patients may present at any age with a painless lump in the clavicle. Although usually mild in terms of cosmetic deformity and typically asymptomatic in younger children, the deformity worsens with age. Dissatisfaction with the cosmetic appearance usually develops by adolescence, and discomfort, especially with throwing activities, may develop. For these reasons, surgical repair is usually recommended when the condition is noted at a young age. The ideal time to repair the pseudarthrosis is between 3 and 4 years of age to take advantage of remodeling of bone with growth. Repair, however, can be accomplished with improved cosmesis and with elimination of discomfort at any age.

Repair of Congenital Pseudarthrosis of the Clavicle (Figs. 22-20, 22-21, 22-22, 22-23 and 22-24)

Several methods of repair have been recommended. Fixation with a Kirschner wire is difficult because of the shape of the clavicle and the potential migration of the wire. However, successful outcome with this technique has been reported (155). This method is less than ideal because the small flexible wire needed to traverse this convoluted shape often breaks. A series of successful cases has been reported using only a suture to secure the bone ends (156). We believe that more rigid fixation is necessary and have used the technique described here with a small reconstruction plate.