Congenital Abnormalities of the Elbow

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CHAPTER 13 Congenital Abnormalities of the Elbow

Peter C. Amadio, James H. Dobyns

INTRODUCTION

Elbow function and configuration are affected by conditions both proximal and distal to the elbow as well as abnormalities at the elbow itself. With this proviso, this chapter discusses congenital anomalies of the region between the shaft-metaphyseal junction of the humerus proximally and the bicipital tuberosity distally, and reviews the current state of knowledge for evaluation and treatment in that region.

CAUSES OF CONGENITAL ANOMALIES

The causes of congenital elbow anomalies follow the same patterns of genetic or somatic damage to the embryo that are seen in other congenital anomalies. Often the most difficult problem is to decide whether the presenting deformity is entirely congenital or perhaps developmental or possibly even traumatic, and whether one or more of these etiologies are interacting. The most common condition in which this difficulty arises, radial head subluxation or dislocation, may be congenital, developmental, or post-traumatic. If it is not present at birth, it may be induced by a relatively trivial injury or merely by a short ulna from any cause. Because so much of the elbow area is cartilaginous at birth, it is difficult to rule out trauma as a possible agent in some dislocations and deformities. In addition, infections, tumors (congenital or infantile), and diseases (e.g., hemophilia) occasionally involve the elbow and may simulate congenital anomaly.

Conditions that commonly involve the elbow are constitutional diseases of bone, metabolic abnormalities, and syndromes featuring limb formation and differentiation failures ^36,^38,^43,^54,^82,⁹⁰ (Table 13-1). Some of the syndromes can be grouped under broad categories such as osteochondrodysplasia,^3,^29,^33,⁹⁰ dysostoses,¹⁸ primary growth disturbances, primary metabolic abnormalities, and congenital myopathies. Most, however, are chromosomal syndromes, from the common dislocation of the radial head⁶⁹ through fairly well-known syndromes such as trisomy 18, fibrodysplasia ossificans progressiva and the Antley-Bixler syndrome⁷ to such rarities as the Bruck syndrome (osteogenesis imperfecta with congenital joint contractures) and a congenital mirror movement syndrome. In some cases, the specific gene locus has now been identified; for example, elbow synostosis may also occur in the context of the multiple synostosis syndrome,⁵³ which has been reported in large family groups and is the result of mutations in genes controlling TGF-b synthesis, including noggin, a protein believed to be important in establishing morphogenic gradients.

TABLE 13-1 Elbow Deformities in Congenital Syndromes

CLASSIFICATION

A multitissue defect classification can be based on the most obvious and most inhibiting tissue defect known to be present. Some degree of defect in other tissues is also commonly noted. The classification consists of three major categories: (1) bone and joint anomalies, (2) soft tissue anomalies, and (3) anomalies involving all tissues. Bone and joint abnormalities at the elbow may include major absences, but more commonly the skeletal structures are present but malformed. The common bone and joint problems are synostosis (Fig. 13-1), ankylosis (Figs. 13-2 to 13-4), and instability (Fig. 13-5). Soft tissue anomalies include malformations with contractures, control deficiencies, isolated tissue anomalies (Fig. 13-6), and congenital tumors (Fig. 13-7). Complete absence or disorganization of the whole limb, including elbow structures, may occur, as in phocomelia (Fig. 13-8); usually, recognizable though dysplastic structures are present (Fig. 13-9). Similar involvement, although more isolated to the elbow area, occurs in the pterygium syndromes.

FIGURE 13-1 A, Lateral and (B) anteroposterior x-ray views of a hypoplastic distal humerus and an apparent radial head subluxation certainly reveal a deformity but probably not a subluxation. Clinically, there was no evidence of a dislocated radial head. C, The opposite elbow showed a radiohumeral synostosis and also a recent fracture just proximal to the synostosis. This case demonstrates the difficulties of differentiation between subluxation, dislocation, and synostosis about the elbow, but the etiology is clearly congenital.

FIGURE 13-2 This anteroposterior view of an elbow in congenital ulnar dimelia shows no radiohumeral joint but two ulnohumeral joints. The appearance is unusual as expected, but no dislocation is noted. Motion of the elbow and forearm is limited by more than 50%.

FIGURE 13-3 A, Elbow and forearm function are, to date, nearly normal in this teenage boy in whom the anteroposterior x-ray view shows ulnar hypoplasia and bowing, distortion of the distal ulnar physis-metaphysis, and subluxation of the radial head. B, The lateral x-ray view shows a similar epiphysis-physis-metaphysis distortion of the proximal ulna with associated joint surface irregularity and shaft bowing. No diagnosis has been confirmed, but this is probably an osteochondrodysplasia. The elbow abnormalities are developmental.

FIGURE 13-4 A, This 18-month-old infant with chondrodysplasia punctata has developmental contractures of many joints including the elbows, where broad metaphyses and irregular, calcified epiphyses (B) are seen.

FIGURE 13-5 This case further demonstrates the overlap between congenital and developmental abnormalities of the elbow. Gradual radial head subluxation due to unequal length of forearm bones is well known in multiple exostosis. These anteroposterior and lateral x-rays demonstrate a severe dislocation of the radial head that was present at birth and was associated with a severe osteochondroma deformity of the distal ulna with inhibition of ulnar growth.

FIGURE 13-6 A, Congenital aplasia of skin and soft tissues at the elbow and proximal forearm results in (B) developmental bone changes in the forearm and elbow.

FIGURE 13-7 A, The anteroposterior (AP) and lateral x-rays of the elbow and forearm in a patient with juvenile fibromatosis reveal marked enlargement of the ulna, posterolateral subluxation of the radial head, moderate enlargement of the distal humerus, and surface irregularities at all aspects of the joint. The changes in the elbows are developmental. B, A much more typical congenital posterior radial head dislocation is revealed in these AP and lateral views (A) and (B) of the elbow of a 14-year-old male with nail-patella syndrome and restricted elbow-forearm motion: 30 to 155 degr7es flexion extension; 45 degrees supination; 60 degrees pronation. His mother has the same diagnosis and the same problem.

FIGURE 13-8 This radiograph of the upper limb of a patient with congenital phocomelia shows a fairly well-developed shoulder and arm, a very hypoplastic hand, and fusion of all elbow elements with the short ulna protruding at right angles to the radius and forearm.

FIGURE 13-9 A, In another instance of generalized congenital hypoplasia of the upper limb, all segments from the shoulder girdle through the hand are equally and severely affected. B, Synostosis of all components of the elbow is present (C), correlated with a hypoplastic and asymmetric forearm plus a hypoplastic hand. D, Hypoplasia of the arm, shoulder, and shoulder girdle is also obvious on this radiograph.

With reference to the bone and joint deformities only, it has been useful to many authors to classify them as congenital, developmental, or post-traumatic. As noted earlier, there is much confusion and interplay between these diagnoses, particularly with reference to radial head subluxation or dislocation. In this classification, congenital refers to a primary genetic dysplasia of the skeletoarticular structure of the elbow, resulting in an observed deformity. Other congenital anomalies or a familial history of similar anomalies help confirm this as an etiology. Developmental refers to elbow skeletal structures that are relatively normal at birth but that are then secondarily deformed by abnormal stresses (perhaps from a congenital shortening of the ulna); by paralysis or other limited motion (arthrogryposis); neural, metabolic, endocrine or dyscrasia disturbances (hemophilia, loss of pain recognition, hemochromatosis, and so on); tumor or hamartomatous involvement (fibromatosis, osteochondromata, and so on), and disease (sickle cell anemia, Gorham’s disease, infections). The post-traumatic etiologic grouping is included in this chapter only because of the continuing confusion over early radial head dislocations, which are often post-traumatic, either as a variant of Monteggia fracture dislocation or as a pure dislocation of the soft cartilaginous radial head pulling through the annular ligament (see Chapter 20) and its residua.

Both early and late, dislocation of the radial head is often diagnosed as a congenital subluxation or dislocation, but it often is not. A radial head subluxation or dislocation in an elbow with normal, neural, muscular, and skeletal structures in both elbow and forearm is post-traumatic until proven otherwise; such an elbow with abnormal skeletal forearm structures is probably due to developmental stresses, but additional trauma may play a part. Such an elbow with a synostosis from birth or other skeletal deformity and no evidence of peri-birth trauma is due to congenital causes, but again, trauma may be an additional factor. The confusions highlighted by this classification have been much discussed in the literature.^14,^20,^38,^45,^51,^54,^61,^70,^71,^72,⁷⁹

DIAGNOSIS

BONE AND JOINT ANOMALIES

Synostosis

Synostoses may occur between all or any two of the three bones present at the elbow. The most common synostosis is that between the radius and the ulna proximally in the forearm, near the elbow (Fig. 13-10), but these two bones also may be joined at any point in their paired course in the forearm. Mital⁵⁵ has classified these synostoses as type I, proximal to the proximal radial physis, and type II, distal to the proximal radial physis. Type II synostoses are more likely to be associated with congenital dislocation of the radial head.⁴⁵ Cleary and Omer¹² suggested a four-level classification scheme, in which Type I is clinically but not radiographically fused with a reduced normal-appearing radial head; Type II is similar but with a clear, bony synostosis; Type III has a hypoplastic posteriorly dislocated radial head; and Type IV has a hypoplastic anteriorly dislocated radial head. Type III appears to be the most common deformity and the one most likely to be associated with significant rotational deformity (almost always pronation). In addition, radiohumeral synostosis, ulnohumeral synostosis, or synostosis among the radius, humerus, and ulna may be present; often, the synostosis is in association with other limb abnormalities, the most common of which is probably ulnar deficiency.^30,^31,^42,^57,⁸⁴ Synostosis may also be associated with fetal alcohol syndrome.⁸⁴ Incomplete synostosis may occur, but often, this is a radiologic appearance rather than an actual occurrence, because complete radiographic synostosis is usually present by maturity.^27,^38,^50,⁸² Cleary and Omer’s five cases of type I synostosis are, however, genuine; all of the patients were skeletally mature at the time of final clinical and radiologic review.¹²

FIGURE 13-10 A, X-ray view of a typical congenital proximal, radioulnar, synostosis. B, The lateral view of the same synostosis is seen but demonstrates no radial head posterior subluxation, although this is commonly seen. C, Oblique view of the typical congenital radiohumeral synostosis of the Antley-Bixler syndrome.

Synostosis between the humerus and either the radius, ulna, or both is less common. Of these, the humeroradial type is most common, followed by humeroradioulnar and humeroulnar types.⁵² However, anatomy is not the whole story, and McIntyre and Benson⁵² have proposed an etiologic classification of developmental elbow synostoses, specifically as to whether the synostosis occurs with (class I, or bony type) or without (class II, or joint type) limb hypoplasia. Within each class, the synostosis can be further characterized as occurring in a sporadic or familial pattern and, if familial, with dominant or recessive inheritance. In familial cases, the condition is usually bilateral.¹² One of the more dramatic presentations is in the Antley-Bixler syndrome, an autosomal recessive disorder characterized by radiohumeral synostosis, cranial synostosis, midface hypoplasia, and a variety of urogenital and cardiac abnormalities (Fig. 13-10C).⁷ Distal radioulnar dislocation is a common accompaniment of many of these syndromes.

Ankylosis

Partial ankylosis of the elbow or the proximal radioulnar joint is often overlooked because limited elbow-forearm motion is common in infancy ²⁸ and often not remarked in childhood. Causes include failure of complete synostosis, intrinsic abnormalities of the joint or surface formation mechanism, and abnormalities of the surrounding soft tissues, as occurs in pterygium cubitale. The joint must be formed correctly, must have adequate surface material and ligamentous support, and must move soon after its formation, or it will become ankylosed, as occurs, for example, in arthrogryposis, or, far more rarely, in Apert’s syndrome.^35,⁸⁹ There are instances when all or part of the elbow appears to be dislocated but proves to be only malformed and limited in motion (Fig. 13-11). Patients with dysplasia, such as those with Apert’s syndrome, may show a progressive loss of motion over time.⁸⁹

FIGURE 13-11 A, Anteroposterior (AP) x-ray view of an apparent radiohumeral dislocation similar to that shown in Figure 13-2 is seen preoperatively. B, A postoperative AP x-ray view 4 years later shows repositioning of what was determined to be a congenital displaced radiohumeral joint without a dislocation of the radial head. C, A lateral postoperative view of the same elbow. Repositioning was obtained when the radius was shortened by removing a segment of the radial shaft. This segment of excised radius was then used to block the repositioned lateral condyle in its new position. This surgical procedure improved the x-ray position of the elbow but did not change function, which demonstrated both preoperatively and postoperatively mild loss of extension-flexion and moderate loss of supination-pronation.

Instability

True congenital elbow instability seldom resembles the post-traumatic condition, but the two are often mistaken for each other. Congenital ulnohumeral dislocation is infrequent except in severe multitissue hypoplasia such as phocomelia, severe ulnar hypoplasia, and severe pterygium syndrome.

The most common problem of instability at the elbow is that of radial head subluxation or dislocation.^1,^2,^11,^20,^22,^25,^38,^47,^48,^61,^64,^67,^78,⁷⁹ When subluxation is an isolated phenomenon, there is considerable doubt about whether it is congenital, developmental, or post-traumatic.^14,^20,^38,⁴⁵ ^,51 The pulled elbow of infancy is a well-known clinical problem that is associated with trivial trauma and laxity or minor tears of the annular ligament.⁶¹ ^,70 ^,72 ^,75 Children have been seen at birth or shortly thereafter with similar problems.^14,^61,⁷⁵ Furthermore, such subluxations in the infant, if not treated by closed reduction or other means, may result in deformities similar to those described as indicative of congenital dislocation of the radial head. It has been said that the degree of deformity in the few cases of known infantile dislocation that have been left untreated but followed suggest that the resulting deformity is milder than that seen in definite congenital hypoplasia at the elbow. This may be so but the so-called criteria for classifying a radial head dislocation as congenital (see later) may be seen after any early radial head dislocation regardless of cause (Fig. 13-12). By contrast, when traumatic dislocation is unreduced in the older child, the development of the radial head and the capitellum remains fairly normal, displaying only minimally those radiographic features said to be characteristic of congenital radial head dislocation. These features are (1) a dislocated or subluxed radial head, (2) an underdeveloped radial head, (3) a flat or dome-shaped radial head, (4) a more slender radius than normal, (5) a longer radius than normal, (6) an underdeveloped capitellum humeri, and (7) a lack of anterior angulation of the distal humerus.^4,^20,^56,^63,⁸⁸ Bilaterality, especially symmetric bilateral dislocation, is usually also considered evidence of a congenital etiology, but this is not an absolute requirement.⁴⁸ However, many if not all the features of congenital dislocation can also be seen with developmental dislocation, due to mild degrees of ulnar or capitellar hypoplasia. In such cases the radial head may slowly dislocate with growth, as the paired forearm bones continue to grow at dissimilar rates.⁴

FIGURE 13-12 Anterior dislocation of the radial head is demonstrated at initial diagnosis (age 2 weeks), at age 4 months, and at age 11 years. In addition to the dislocation, there is a reversal of the ulnar curve and some convexity of the radial head. The etiology is probably post-traumatic.

There may be only one absolute criterion of congenital elbow dislocation—dislocation with severe hypoplasia of all the osseous elements of the elbow. Absence of the capitellum is probably an example of congenital aplasia, but hypoplasia of the capitellum may occur after dislocation from any cause, as may a deformity of the radial head (see Chapter 20).

When radial head dislocation is familial, bilateral, or seen at birth, or when it occurs with other musculoskeletal anomalies, particularly anomalies in the same upper limb, the evidence is strong that the radial head dislocation is congenital. Cases that are diagnosed later in life may be associated with a discrepancy in length of the paired forearm bones and, therefore, may fall within the “developmental” category. It is well known that inadequate length of the ulna from any cause will result in increased compressive stresses along the radius, gradually leading to a subluxation and perhaps a dislocation of the radial head.^38,^47,⁷⁹ Such subluxations, therefore, also may be a secondary phenomenon.⁴⁸

Approximately half of all patients with isolated congenital radial head dislocation will have a problem bilaterally.^2,^48,⁵⁶ Bell and associates⁴ have classified isolated congenital dislocations of the radial head as type I, subluxation; type II, posterior dislocation with minimal displacement; and type III, posterior dislocation with significant proximal migration of the radius. Type I is the least common dislocation but the one most likely to be associated with pain. Types II and III appear to be roughly equally prevalent. Type III is associated with the most loss of motion, usually supination. Deformity of the radial head without subluxation also has been reported.²² Finally, Wiley and colleagues⁸⁶ have reported congenital anterior and lateral dislocations.

SOFT TISSUE ANOMALIES

Soft tissue anomalies or absences may interfere with elbow function as much as bone or joint deformities. These anomalies have been subdivided into syndromes with contractures (pterygium syndromes, congenital muscular atrophy and myopathy syndromes), control deficiencies, isolated tissue anomalies (triceps absence or contracture), and congenital soft tissue tumors.

Contractures

The classic malformation with contracture is pterygium cubitale, in which almost every soft tissue is abnormal and a severe flexion contracture exists.^23,²⁴ The condition also has been called cutaneous webs and webbed elbow; it is but one manifestation of a congenital syndrome that may affect the neck, axilla, elbow, knee, or digits. A survey of 240 cases of cutaneous webs reported in the literature included 29 in the region of the elbow.²³ The web may be unilateral or bilateral, or symmetric or asymmetric. The condition has been reported to result from both an autosomal dominant and a recessive gene. Associated abnormalities involving almost every body system have been reported.^38,⁸² Other conditions resulting in formidable contractures about the elbow include fibrodysplasia ossificans progressiva and arthrogryposis.

Control Deficiencies

Arthrogryposis and its related syndromes are also included in this group but also are discussed elsewhere (see Chapters 71 and 72). Both flaccid and spastic palsies affect elbow control and range of motion. Simple absences or deficiencies of tissue also affect elbow control. Hypoplasia of the elbow includes deficient growth not only of osseous structures but also of the related soft tissue control elements and cover structures.^13,^58,⁸¹ Most characteristic is probably the extension contracture of arthrogryposis.⁸⁷

Isolated Tissue Anomalies

The skin may be deficient or missing, with absence, hypoplasia, or scarring of the underlying tissues. Nerve, vascular, and lymphatic anomalies in the region of the elbow are common.³⁸ The anconeus epitrochlearis occasionally is present as an anomalous muscle and may cover the ulnar nerve in the cubital tunnel area, contributing to the possibility of entrapment. Other anomalous muscles that may cause nerve entrapment problems are (1) Gantzer’s muscle, an anomalous head of the flexor pollicis longus or flexor profundus that usually originates from the medial epicondyle or the coronoid process of the ulna and occasionally is a factor in anterior interosseous nerve compression; (2) a solitary head of the supinator and other anomalies of this muscle; (3) accessory muscles of the anterolateral aspect of the elbow, including the accessory brachialis or accessory brachioradialis; (4) variations in the head, origin, or insertion of the pronator teres; (5) variations of a similar nature in the flexor carpi radialis, the flexor carpi ulnaris, and the palmaris longus ⁵³; and (6) an aberrant medial head of the triceps, which may snap over the medial epicondyle and irritate the ulnar nerve.¹⁶

Congenital Soft Tissue Tumors

Tumors of the soft tissue are rare but include a wide variety of abnormalities, ranging from overgrowth to neoplasms and from multitissue hamartomas to single tissue entities. Probably the two most common tumors in the infant are the fibromatoses and vascular tumors. If the elbow area is involved, there is usually some limitation of motion.

COMBINED BONE AND SOFT TISSUE ANOMALIES

Soft tissue anomalies may coexist with mild osseous anomalies, such as those related to the supracondyloid process.^13,^53,⁸⁰ The supracondyloid process is an anomalous bony prominence extending from the anteromedial aspect of the distal third of the humerus. Struthers⁸¹ in 1848 described the ligament associated with this process, and since then, various anomalies have been reported in connection with it. These include a more proximal branching of the ulnar artery off the brachial artery above the bony spur, a more proximal insertion of the pronator teres on the bony process, and various relationships of the neurovascular structures with bone and ligament. The symptoms—pain, tingling, numbness, and so on—usually are neuralgic, but they may be vascular.

Many of the congenital anomalies already discussed are manifest in both osseous and soft tissues. These abnormalities may be equivalent as in the supracondyloid process syndrome just discussed, or predominantly in one tissue, as in fibromatosis. More severe changes are seen with severe pterygium cubitale and severe forms of ulnar hypoplasia and phocomelia. In pterygium cubitale, or congenital webbed elbow, a skin web extends from the upper arm across the volar elbow to the forearm. Flexion is usually possible, but extension, pronation, and supination are severely limited. The muscles and neurovascular structures are incompletely developed. The bones are hypoplastic and deformed, and the elbow joint often is dislocated or severely hypoplastic. Fibrous strands represent missing muscles or tendons. Muscle hypoplasia is present posteriorly as well as anteriorly.

Severe ulnar hypoplasia is marked by radial head dislocation, diminishing segments (ranging from small to nonexistent) of the proximal ulna, variable but seldom normal motion and stability, and muscle and neurovascular abnormalities. Conditions are more normal proximal to the elbow, but distally, more abnormalities are apparent; the ulnar forearm and hand structures are particularly dysplastic. Lorea et al ⁴⁶ have proposed a classification of these findings based on a review of their own experience with 46 patients and a literature review. They propose three elbow types: type 1, normal; type 2, radiohumeral synostosis; and type 3, radial head subluxation. They further recommend subclassifying the elbows as having extension (type E) or flexion (type F) contractures. Unfortunately, they do not give the distribution of these types in their series. Phocomelia may present with similar findings, or the elbow may be even more dysplastic or absent altogether (hand, wrist, or forearm may be attached directly to the shoulder or trunk).

TREATMENT OF BONE AND JOINT DYSPLASIAS

TREATMENT OF SYNOSTOSIS

The treatment of synostosis of the elbow joint, whether radiohumeral ⁶⁰ or ulnohumeral, is dictated by the position of the forearm-wrist-hand unit and the function of the wrist-hand unit. These treatments have changed little over the past few decades. If the hand is absent or nonfunctional, repositioning of a synostotic elbow is clearly less important. If the hand is functional and the elbow is in a “functional” position (i.e., somewhere near midflexion), especially if the contralateral limb is normal, no treatment is likely to be necessary. For bilateral synostoses, some consideration probably should be given to positioning one arm in relative flexion and the other in relative extension.

Frequently, only one forearm bone is well represented, and this may be bowed or deformed in some manner as well as short. In addition, there may be a rotational deformity. The forearm-wrist-hand unit may point directly posterior when the upper limb is in its usual dependent position beside the torso. Although simple rotational deformities can be corrected by osteotomy at any level, multiplane deformities should be corrected at the site of maximum deformity—that is, the humeral-forearm junction—perhaps extending the correction distally in the forearm (Fig. 13-13). One such method involves a posterior approach and a multiple-segment corrective osteotomy, making one or more of the segments trapezoidal in shape and rotating it 180 degrees, if necessary, to realign the unit as desired. If only one limb is involved, this desired position is usually at maximum length, with the forearm, wrist, and hand in the midposition. Derotation should be accomplished in the direction that causes the least torsion of the neurovascular structures, commonly from an internally rotated position through a clockwise rotation to a forearm midposition. Hyperextension, if present, is corrected simply to neutral or slight flexion, and the osteotomy segments are adjusted to make the best contact in the desired position; a segment may be excised if this is needed for contouring. If both limbs are involved, enough elbow flexion angle should be included on one side to allow one of the limbs to reach the face and the head. Arthroplasty has been attempted ^30,^31,^39,⁵⁷ but with indifferent results; the usual result is recurrence.

FIGURE 13-13 A, Typical congenital radiohumeral synostosis with marked curving of the radial segment. B, A “shish kabob” corrective osteotomy was carried out with temporary internal fixation. Excellent correction resulted, and there were no complications. The elbow synostosis resulted in a posterior pointing forearm, wrist, and hand.

Proximal forearm synostosis may occur with elbow synostosis, in which case the elbow is derotated as described previously. If, however, proximal radioulnar synostosis occurs in the presence of a functioning elbow joint, derotation of the forearm alone may be required. The indications for this procedure seem limited. Most patients have little functional deficit.¹² Compensatory rotation at the wrist appears to be an important factor in minimizing symptoms.⁶² Although many authors have attempted and a few have claimed success for passive and even active mobilization of the forearm,^8,^15,^19,^27,^37,⁵⁵ there is no body of literature that substantiates these results in a significant number of patients who have been followed for an adequate period of time. When attempted, these procedures usually involve excision of the proximal radius, including the synostotic mass; division of the entire length of the interosseous membrane; interposition of some material between the contact areas of the radius and the ulna; and tendon transfers, such as rerouting the extensor carpi radialis longus to the volar wrist for supination and the flexor carpi radialis to the dorsal wrist for pronation. A similar procedure involving the interposition of a metallic swivel has been described by Kelikian and Doumanian,³⁷ but few long-term results have been reported.

A more reliable procedure is that of derotation osteotomy.^27,⁷⁶ This procedure is best outlined by Green and Mital,^24,⁵⁵ who perform the rotational osteotomy through the synostosis itself. It is indicated primarily when the forearm is fused in the extreme of either pronation or supination; forearms synostotic in neutral or close to neutral function well and often are diagnosed only later in infancy or childhood because of this fact. The synostosis is approached through a dorsal incision and is transversely osteotomized. A radioulnar (in the coronal plane) K-wire or Steinmann pin is then placed distal to the osteotomy site and is left protruding externally on both sides. A longitudinal (in the sagittal plane) pin is then placed from the olecranon across the osteotomy site, and corrective rotation is carried out as desired. Because the indication is an extreme pronated or supinated position, in most instances, 70 to 90 degrees of rotation from pronation toward supination is required. If circulatory deficits appear during or after this derotation, less rotation is accepted, although an additional amount may be carried out 10 to 15 days later. The radioulnar pin may be fixed by either a plaster cast or an external fixation apparatus. Internal fixation should not be used because alteration of forearm rotation may be necessary to diminish circulatory difficulties. Goldner and associates ²¹ claim that these circulatory problems may be minimized by the use of derotation in the distal forearm (radius only in younger patients; radius and ulna in older patients). Their results have yet to appear in the literature except in abstract form, but the rationale seems reasonable and the technique appropriate. They recommend cross-pin fixation in children and plate fixation in adolescents and adults.

One new and unusual problem has been reported recently, as an acute sequela of proximal radioulnar synostosis: flexion contracture. Matsuko et al ⁴⁹ have reported five cases in which an acute hyperflexion episode had resulted in the sudden onset of a fixed flexion contracture in teenaged boys (in four of the five cases). In each case, the problem was treated surgically. Through a lateral approach, the anterior elbow capsule was identified. In each case, a thickened band of anterior capsule was identified, under which the hyperflexed, anteriorly displaced radial head had become trapped. A simple excision of the band resulted in complete correction in each case.

TREATMENT OF ANKYLOSIS

Ankylosis that does not involve synostosis, subluxation, or dislocation of the elbow may occur. Paralyses, muscle disease, and other soft tissue abnormalities commonly restrict motion; treatment of these abnormalities is discussed elsewhere (see Chapters 71 and 72). Abnormalities of joint shape and joint cartilage occur but are usually treated only by physical therapy. Rotation ankylosis due to soft tissue abnormalities occurs but has minimal effect on the elbow; its treatment requires release not only of the proximal radioulnar area but also in the forearm and wrist.⁵

TREATMENT OF INSTABILITY

Treatment of infantile dislocations of the radial head, whether congenital, developmental, or traumatic, depends on the degree of hypoplasia present in the forearm and elbow area. If in doubt about the configuration of the various components of the elbow joint, an arthrogram should be performed ⁶¹; this study may show that there is no dislocation at all but merely a deformed elbow joint with the radiocapitellar joint displaced from the usual position (see Fig. 13-12). Attempts at open reduction have been made, but the result is often recurrence unless both annular ligaments and ulnar length/configuration are restored (Fig. 13-14). Most authors do not advise the procedure,^4,^56,⁸⁶ although recently Sachar and Mih⁷¹ have reported good short-term results (maintenance of reduction and improved forearm rotation) in 10 of 12 children with congenital radial head dislocation operated on between ages 7 months and 6 years. They reported that the most common finding was an interposition of the annular ligament, which they divided and then repaired in its anatomic position. Follow-up was short, however, averaging less than 2 years, with the longest being only 41 months.

FIGURE 13-14 A, Anteroposterior and lateral x-ray views of a radial head dislocation in a limb with other congenital anomalies but with a fairly normal skeleton at the elbow. Although this fulfills the requirements usually listed for congenital dislocation, the dislocation may simply be developmental, related to the unequal length of the two forearm bones. B, Postoperative lateral radiogrphs after open reduction of the dislocated radial head and internal fixation. A second operation was carried out a year later, at which time the radius was shortened and the annular ligaments were reconstructed; repeat reduction of the radial head also was performed.

The alternative to attempted reduction of congenital or infantile radial head dislocation is to accept the imposed disability (some limitation of forearm rotation, ranging from a few degrees to more than 90 degrees; occasional limitation of elbow motion; and infrequent pain) and proceed with radial head excision, if needed, at maturity.¹⁹^–²¹ ^,38 ^,48 ^,79 As noted in a long-term follow-up study,⁴ painful arthritis is typical only of the least common type I deformity. Relief of pain and cosmesis are more likely to be benefited from surgical excision; motion is seldom improved.⁴

TREATMENT OF SOFT TISSUE DYSPLASIAS

Treatment of most soft tissue problems at the elbow level is discussed in other chapters. Arthrogryposis, as well as other flaccid palsies, is covered in Chapter 71. Spastic neurogenic problems are discussed in Chapter 72, and nerve entrapment around the elbow is discussed in Chapter 80. Successful treatment for other soft tissue dysplasias at the elbow is rare. Aplasia cutis congenita has occurred in the elbow area. In the author’s experience, it was associated with scarring and hypoplasia of the regional forearm muscles plus reactive deformity of the underlying bones. Resurfacing with a skin and subcutaneous flap was eventually necessary, followed by tendon transfers, which in this instance were required to provide extensor function of the wrist and hand. Muscle anomalies may result in either mechanical problems (snapping or catching)¹⁶ or neurovascular entrapment, as discussed in Chapter 80.

TREATMENT OF COMBINED BONE AND SOFT TISSUE DYSPLASIAS

Pterygium cubitale remains an unsolved challenge. Attempts at treatment have included Z-plasty, skin grafts, and release of other tight structures. Improvement has been limited, and risks are high.^23,²⁴ Because there is no substantial report in the literature describing a reliable and useful method of treatment, no recommendations for surgical treatment are offered. Techniques of bone shortening to permit a greater safe excursion of the neurovascular structures or techniques of vascular and nerve grafting have been attempted, but adequate reporting is not yet available. The lengthening-stretching techniques of Ilizarov have been tried by a few investigators, so far with limited success. The hands in pterygium cubitale are often deficient also, but because limited excursion of the elbow is available in flexion, at least they are usually able to reach the upper trunk, the face, and the head.

In severe forms of ulnar dysplasia, the elbow often displays adequate range and stability. Occasionally, the displaced radial head is sufficiently limiting or symptom provoking so that treatment is offered. Although excision of the radial head and a sufficient portion of the shaft to resolve the mechanical block might suffice, the desire to stabilize and lengthen the forearm plus the fear of recurrent encroachment by the radial shaft usually lead to a recommendation for a one-bone forearm procedure (Fig. 13-15).⁹ This is carried out as follows:

1. Use a long lateral incision that covers the distal half of the arm, the elbow, and the proximal half of the forearm.

2. Mobilize the anterior flap, identify and protect the radial nerve, and identify and mobilize the anteriorly and radially dislocated radius.

3. Mobilize the posterior flap, identify the short ulnar fragment, and uncover the interosseous space.

4. With both bones visualized through both anterior and posterior intervals (obviously, the procedure can be performed through an anterior approach only or through both a proximal anterior and a distal posterior approach, but we have found that access and safety are preferable this way), the maximum forearm length that the soft tissue will accept is judged by manual displacement.

5. The radius then is osteotomized at the length just determined, and the proximal fragment is removed.

6. The distal fragment is aligned with the short ulnar fragment, and contact is maintained by an intramedullary pin drilled through the olecranon, along the ulnar medullary cavity, across the osteotomy site, and along the radial intramedullary space until it penetrates the radial cortex at some point. (The forearm position, usually the midportion, should be set before this distal penetration occurs.)

7. The usual support dressings (long arm splint-dressing combination initially, perhaps changed to a long arm cast later for the older child) are used until healing occurs (4 to 6 weeks). The supports are then discontinued, and the pin is removed.

FIGURE 13-15 A, A lateral view of an elbow in ulnar agenesis shows an apparent dislocation proximally and anteriorly of the radial head. Although the ulnar agenesis is congenital, the dislocation is probably developmental. Clinical findings suggested that this was a true dislocation. B, There is occasional need for excision of the dislocated radial head and combination of the proximal ulna and distal radius to form a one-bone forearm, as seen here. This changes both the appearance and the function of the elbow as well as the forearm (the range of motion of the elbow is usually improved; the forearm position becomes fixed).

In phocomelia, the elbow is seldom the site of the infrequent surgical attention given to this condition, but there may be an occasional indication for a one-bone forearm procedure or for simultaneous lengthening and stabilization at an unstable elbow segment.⁷⁷

COMPLICATIONS

Overtreatment

In many cases, the severe upper limb anomaly, particularly if it is of the sporadic variety, is associated with a completely normal contralateral upper limb. In such cases, surgical treatment may have little effect on the long-term functional level of the patient.⁶ Therefore, it also is important to consider the likely practical gains from therapy before proposing an intervention. As has been noted, many synostotic forearms function well, even if in a poor position owing to compensatory hyper-rotation at the wrist. Such factors need to be considered carefully before embarking on a surgical adventure.

CONGENITAL ELBOW REDUX

Can a topic be brought to life, or at least reinvigorated? These questions arise as the authors peruse their prior efforts and the literature since those efforts and note that little has changed. There is still uncertainty regarding the relative incidence of the two most common congenital problems at the elbow, radial head subluxation or dislocation versus proximal radio-ulnar synostosis. Treatment for radial head dislocation still runs the gamut from waiting for symptoms/disability, then removing the radial head ¹⁰ to open reduction, which may vary from removal of the annular ligament from the joint and reconstructing it in normal position to open reduction, corrective osteotomy of the ulna and reconstruction of an annular ligament, similar to the methods used for similar problems in old Monteggia injuries.⁸⁵ Usually, radioulnar synostosis continues to be treated by corrective osteotomy, although new methods have been designed with osteotomies of both the radius (distally) and the ulna (proximally) with immediate correction if the deformity is not too severe⁵⁹ or staged correction for the severe deformities.⁴⁴ The venturesome among us are still, case by case, trying synostosis excision and interposition of various substances, recently using a vascular fascio-fat graft.³⁴ The association of radial head subluxation or dislocation with other conditions continues to be newsworthy with new reports including congenital pseudarthrosis of the forearm⁴¹ treated by a one-bone forearm procedure in one case²⁶ and treated by resection and internal fixation plus a vascularized fibular graft in another case.⁶⁸ There are many reports of radial head subluxation or dislocation with other conditions^17,^40,⁷³ and with paralyses.⁶⁵ It is well known that shortening of the ulna from any cause risks of subluxation or dislocation of the radial head, but the association with radial longitudinal deficiency (44% of extremities with type 1 [more than 2 mm. shortening of the radius] radial deficiency³²) is not as well known. However, it is certain that there is a familial component to some instances of radial head dislocation.⁶⁹