Congenital Hand Contractures in Pediatrics

Congenital hand contractures in pediatrics refer to joint stiffness or limited movement present at birth, often impacting a child's ability to perform daily activities. These conditions are not progressive, but their severity and presentation vary greatly. Understanding the different forms, their clinical features, and available treatment options is crucial for effective management and improving a child's functional independence.

Understanding Congenital Hand Contractures in Pediatrics: An Overview

Arthrogryposis (Arthrogryposis Multiplex Congenita) is a syndrome characterized by nonprogressive joint contractures present at birth. These contractures stem from a lack of fetal motion during development, which can be caused by muscle or nerve abnormalities, restricted intrauterine space, vascular insufficiency, or maternal illness. Often, the precise cause remains unknown.

Several syndromes and genetic conditions feature arthrogryposis. Notable examples include:

• Freeman-Sheldon syndrome (whistling face syndrome), an autosomal dominant condition affecting hands, feet, and facial appearance.
• Beals’ syndrome, an inheritable condition presenting with contractural arachnodactyly and proximal interphalangeal (PIP) joint flexion contractures.
• Windblown hand (congenital ulnar drift), also part of the arthrogrypotic spectrum and often inherited as an autosomal dominant trait.

These contractural conditions frequently have a genetic component, showing significant variation in how they manifest within affected families.

Clinical Features of Arthrogryposis

Amyoplasia congenita, often called “classic arthrogryposis,” is the most common form, characterized by symmetric limb positioning. It occurs sporadically.

Upper extremity posture typically involves:

• Shoulder adduction and internal rotation
• Elbow extension
• Forearm pronation
• Wrist flexion
• Hand ulnar deviation

Digits are often stiff and postured in flexion. A contracted clasped thumb is a common and functionally challenging finding. Other features include waxy skin lacking creases, significant muscle wasting, and a paucity of subcutaneous tissue.

Treatment Goals for Pediatric Hand Contractures

Treatment for arthrogrypotic contractures is highly individualized. For the upper extremity, goals include achieving independent function for self-feeding and perineal care, increasing active and passive motion, and preserving bimanual use when critical. A collaborative team approach involving physicians and therapists is essential. Adaptive equipment and technology can also significantly boost independence. Often, upper and lower extremity surgeries may be combined to reduce the number of general anesthetics required.

Nonoperative Management of Congenital Contractures

Early treatment primarily focuses on frequent passive movement of all affected joints and the strategic use of splints. Static progressive splinting, which applies a low-load, prolonged stretch, can effectively reduce contractures. Increased passive motion is vital for function and enhances the potential for surgical reconstruction.

Passive stretching, serial casting, and orthotics are particularly effective for distal arthrogryposis. However, joint contractures in amyoplasia tend to be rigid and often resist therapy.

Surgical Management: Timing and Considerations

The timing of surgery remains a subject of debate. Early treatment (before school age, around 4-5 years) is often recommended to minimize compensatory movements and optimize mainstream school function. Older children often develop adaptive maneuvers that, while appearing awkward, are functional for many tasks, such as using bimanual limb scissoring for grasp. Surgical recommendations must carefully consider these adaptations to ensure no degradation of function post-surgery.

Shoulder and Elbow Surgical Interventions

The shoulder often presents with limited motion due to underdeveloped musculature, capsular contracture, and joint incongruency, leading to internal rotation deformity. Reliable procedures to enhance shoulder mobility are scarce. Severe internal rotation that severely limits limb function is rare but may necessitate treatment. Soft tissue procedures are generally ineffective and could compromise compensatory functions like brachiothoracic pinch.

Humeral osteotomy to rotate the arm into a better functional position is more reliable, with slight internal rotation often preferred for hand-to-mouth function and midline use.

The elbow is frequently the most challenging joint. A lack of flexion severely limits hand-to-mouth function. The primary goal is to restore passive motion. Early efforts in therapy to restore passive elbow flexion are critical. If elbow extension remains recalcitrant, surgical release via triceps lengthening and posterior capsular release may be considered. A posterior surgical approach involves isolating the ulnar nerve, lengthening the triceps (e.g., Z-plasty or V-Y technique), and dividing the posterior capsule to achieve greater than 90 degrees of flexion.

Restoration of active elbow flexion is a secondary goal, requiring passive flexion as a prerequisite. Posterior release alone does not achieve active flexion. Donor muscles for elbow flexorplasty are limited in amyoplasia due to poor quality or paucity. Bipolar pectoralis major and latissimus dorsi transfers are options, but results are less predictable than in post-traumatic cases. The Steindler flexorplasty, using the flexor-pronator mass, is contraindicated in children lacking strong active wrist extension, as it can worsen wrist flexion contracture.

Forearm and Wrist Surgical Interventions

Typical contractures include forearm pronation, wrist flexion, and ulnar deviation, with variable severity. Overcoming wrist malposition is challenging due to rigid volar structures and deficient active wrist extension. Carpal coalitions and fixed bony changes accumulate with skeletal maturity. Persistent wrist flexion that resists therapy may require surgery to improve functional positioning.

Various surgical procedures have been proposed:

• Proximal row carpectomy: Historically used for mild to moderate flexion in young patients, but results are often unpredictable, frequently insufficient for severe deformities, and long-term follow-up shows recurrent flexion and secondary bony changes.
• Distraction of soft tissue with multiplanar fixation: Reported to correct wrist position, requiring careful pin placement and patient compliance, but long-term outcomes are still emerging.
• Arthrodesis: Avoided as it eliminates all radiocarpal motion, serving as a salvage procedure.
• Osteotomy (preferred): Dorsal wedge osteotomy of the mid-carpus is the preferred approach to correct both wrist flexion and ulnar deviation. This site avoids growth plate jeopardy and addresses the maximum deformity more effectively than radial osteotomies.

The surgical technique for dorsal wedge osteotomy involves both volar and dorsal approaches. Taut wrist flexors may be incised, lengthened, or considered for transfer to the dorsum for wrist extension (extensor carpi ulnaris is preferred). A biplanar wedge resection is planned on the mid-carpus to straighten and position the wrist in slight extension. Fixation is achieved with interosseous sutures and Kirschner wires. Post-surgery, the limb is immobilized in a long arm splint, followed by splint fabrication and active motion.

Thumb and Fingers Surgical Interventions

Fingers are typically stiff, fixed in flexion, and ulnarly deviated, sometimes with mild to moderate digital overlap. Surgical treatment to restore supple finger motion is generally unsuccessful. Osteotomy may be used to realign poorly positioned fingers. A contracted clasped thumb is a common finding and may require release from the palm to enhance prehension and function.

Camptodactyly: A Specific Hand Contracture

Camptodactyly is a painless, typically progressive flexion contracture of the proximal interphalangeal (PIP) joint, without intra-articular or periarticular swelling. Metacarpophalangeal (MP) and distal interphalangeal (DIP) joints are not directly affected, though compensatory deformities can develop.

It is classified into reducible (flexible) and irreducible (fixed) types, guiding different treatment approaches.

Incidence and Characteristics of Camptodactyly

Most cases are sporadic, but it can be inherited as an autosomal dominant trait with variable expressivity. It affects less than 1% of the population, with most cases being mild and asymptomatic. Camptodactyly is bilateral in about two-thirds of patients, though often asymmetric. The fifth finger is most commonly involved, with incidence decreasing towards the radial side of the hand.

Categories of Camptodactyly

1. Type I (Infant or congenital): Most common, appearing in infancy as an isolated finding, usually limited to the fifth finger, affecting males and females equally.
2. Type II (Preadolescence or acquired): Appears between ages 7 and 11, affecting girls more than boys. It often does not improve spontaneously and may progress to severe flexion deformity.
3. Type III (Syndromic): Severe deformity involving multiple digits of both extremities, associated with various syndromes (e.g., craniofacial disorders, short stature, chromosomal abnormalities).

Pathophysiology of Camptodactyly

The precise cause is unknown, and there is no consensus on its pathogenesis, with almost every structure around the PIP joint implicated. Proposed anomalies include:

• Skin and subcutaneous tissue: Deficiency or contracture in the dermis, fibrotic changes in subcutaneous tissue/fascia.
• Periarticular alterations: Contractures of collateral ligaments or volar plate.
• Musculotendinous anomalies: Abnormalities of flexor tendons, intrinsic muscles (lumbricals, interossei), and extensor apparatus. The flexor digitorum superficialis (FDS) has been described as contracted, underdeveloped, or lacking a functional muscle. An aberrant lumbrical muscle is also frequently implicated, with abnormal origin or insertion. Deficiency of lumbrical muscles can lead to an intrinsic-minus deformity.
• Bone and joint deformities: Atypical PIP joint configurations, especially the head of the proximal phalanx and base of the middle phalanx. Long-standing cases show changes like a misshapen proximal phalanx head and flattened, potentially subluxated, middle phalanx base.

Persistent PIP joint contracture leads to secondary alterations, such as bowstringing palmar skin, abnormal fascial bands, and changes in joint configuration.

Diagnosis of Camptodactyly

Type I manifests at birth or in infancy. Type II begins subtly and progresses, often becoming severe during the adolescent growth spurt. Pain is uncommon; rather, the angulation and appearance are noted. The examination assesses active and passive motion of the PIP joint, differentiating flexible from fixed contractures. Active PIP joint flexion is typically preserved.

The amount of passive PIP joint extension is determined by varying wrist and MP joint positions. Increased passive extension with wrist/MP joint flexion suggests tight extrinsic flexors (FDS). The central slip tenodesis test evaluates central slip integrity. Compensatory MP joint hyperextension is common. Radiographs (anteroposterior and lateral) evaluate PIP joint configuration and surrounding bones, revealing long-standing changes.

Treatment Indications for Camptodactyly

Conservative management is the mainstay for mild camptodactyly (less than 30-40 degrees) that doesn't interfere with activity. Patients are advised to accept the deformity, and static night splinting is recommended to prevent progression. Many cases (80%) show no improvement or progression. Severe involvement warrants treatment, but full motion restoration is unrealistic, especially with bony changes.

Nonoperative Treatment of Camptodactyly

A preliminary period of nonoperative treatment is almost always attempted to resolve or decrease fixed flexion deformities. This includes formal therapy with stretching, static and dynamic splinting, and serial casting. Splints for infants must be forearm-based. Recommended splint wear varies, but long-term part-time splinting is often needed until skeletal maturity.

Operative Treatment of Camptodactyly

Surgery is reserved for severe deformities that fail conservative management. A global approach addressing all potential causes and secondary deformities is recommended. Procedures may include:

• Division of offending agents (fascia, skin, tendons, sheath, capsule, ligaments).
• Reconstruction or augmentation of the extensor mechanism.
• Bony procedures about the PIP joint.

Surgical Technique

The PIP joint can be approached via palmar or mid-lateral incisions, with local skin rearrangement (e.g., Z-plasty) or skin grafts needed for complete extension. Deeper dissection involves graduated release of contracted structures. Anomalous fascia, fibrous bands, and intrinsic muscles (lumbrical, interosseous) are resected. The FDS tendon is assessed and, if anomalous, may be released or excised.

Tendon Transfer

Used in adolescents unable to extend the PIP joint with MP joint flexion. FDS tendon from the small finger (if independent) can be transferred to the extensor apparatus. The FDS can also be split for multiple digits or an adjacent FDS or extensor indicis proprius used as a substitute donor. This decreases PIP flexion force and enhances extension, but risks swan neck posturing and loss of flexion.

Salvage Procedures

For severe flexion deformities with secondary bony changes, bone realignment is primary. This can involve dorsal closing wedge osteotomy of the proximal phalanx or PIP joint fusion. Osteotomy corrects posture but doesn't change overall motion, leading to reduced flexion and grasp. PIP joint arthrodesis sacrifices all motion. External fixation, such as with the Digit Widget, has shown promise in correcting severe PIP joint contractures, allowing for finger flexion during treatment.

Complications

Surgery for severe camptodactyly carries high risks, including neurovascular injury, skin sloughing, and loss of motion due to scar formation. Early mobilization is crucial to prevent adhesion formation and maintain flexion, though return of flexion can be slow. Ankylosis of the PIP joint has been reported, especially with attempts at joint surface remodeling.

The Contracted Clasped Thumb: A Functional Challenge

A congenital clasped thumb describes a spectrum of anomalies in thumb morphology. Normal infants hold their thumbs in the palm but should show full, symmetric extension during a startle reflex. Persistence beyond 3-4 months warrants observation for developmental delays.

Classification of Clasped Thumb

1. Type I (Mildest form): Due to absence or hypoplasia of the extensor pollicis brevis (EPB), often presenting as a thumb that doesn't fully extend. Normal motion at IP and CMC joints is preserved. Stretching and splinting often resolve the issue.
2. Type II (Moderately severe): Lacks full passive range of motion, with MP joint flexion contracture, skin deficiency, and joint abnormalities. Passive MP joint extension and CMC joint abduction are limited by soft tissue deficiencies. Passive IP joint extension and active IP joint flexion are preserved.
3. Type III (Severe): Lacks passive motion at CMC, MP, and IP joints. Often features true thenar and adductor deficiency combined with extrinsic flexor tightness. This is commonly seen in arthrogrypotic syndromes like amyoplasia and Freeman-Sheldon syndrome.

Other descriptive names include pollex varus, adducted thumb, and persistent thumb-clutched hand.

Treatment Goals and Timing for Clasped Thumb

The primary goal is to restore the ability to position the thumb for grasp, enhancing pinch and dexterity. Initial treatment involves frequent stretching and splinting, utilizing infant skin plasticity. Reconstruction can await growth to minimize anesthetic risks and ease tissue handling. Surgery must address four main components:

1. Intrinsic muscle contracture and deficiency.
2. Deficiency of the thumb skin and soft tissue envelope.
3. Extrinsic tendon deficiencies.
4. Stiff and abnormal joints.

Reconstructive Strategy for Clasped Thumb

Skin Envelope

It's crucial to determine the plane(s) of skin and soft tissue deficit. Deficiencies can involve the thumb-index finger web space and/or the palmar aspect of the thumb. Combined deficiencies are most common. Single-plane deficiencies can be augmented with local rotation flaps (e.g., Z-plasty). Two-plane deficiencies require additional tissue from outside the deformity zone, such as a rotational flap from the radial aspect of the index finger.

Full-thickness skin grafts are less satisfactory over neurovascular structures at joint creases, and split-thickness grafts should be avoided.

Intrinsic Muscle Contracture

Release of the origins of the thenar musculature from the transverse carpal ligament helps bring the thumb metacarpal out of the hand's plane. This is done stepwise through an incision parallel to the thenar crease, protecting the palmar cutaneous branch of the median nerve and the thenar motor branch. The origins of the short abductor and flexor pollicis brevis are dissected, and the transverse and oblique heads of the adductor pollicis are released. This preserves MP joint stability and function while allowing improved abduction and extension.

Extrinsic Tendons

Abnormalities include contracture of the flexor pollicis longus and absence/hypoplasia of one or both extrinsic extensors. Flexor pollicis longus function varies; a long Z-lengthening may be needed, or primary transfer of an adjacent flexor tendon in severe cases. Extensor tendon reconstruction may be deferred to a second stage. Isolated absence of the EPB usually doesn't require transfer. Absence of both thumb extensors is best reconstructed with a tendon transfer, with the extensor indicis proprius being preferred, or extensor digiti minimi or a slip of the index finger EDC as alternatives.

Metacarpophalangeal (MP) Joint Flexion Contracture

For mild to moderate MP joint contracture, addressing skin and tendons suffices. In severe cases where these measures are insufficient, primary MP joint arthrodesis (chondrodesis) is performed. This stabilizes the MP joint in extension, positioning the thumb out of the palm for better prehension and function.

Frequently Asked Questions (FAQ) about Congenital Hand Contractures

What is Arthrogryposis Multiplex Congenita?

Arthrogryposis multiplex congenita is a syndrome of nonprogressive joint contractures present at birth, caused by a lack of fetal motion. It involves multiple forms with varying clinical features and severity.

How is Camptodactyly diagnosed in children?

Diagnosis involves assessing active and passive motion of the PIP joint, noting any fixed flexion contracture, and observing how passive extension changes with wrist and MP joint positioning. Radiographs help assess joint configuration and bony changes.

What are the main treatment options for a Contracted Clasped Thumb?

Initial treatment includes frequent stretching and splinting. Surgical reconstruction is often required and addresses intrinsic muscle contracture, skin and soft tissue deficiency, extrinsic tendon deficiencies, and stiff joints. Procedures can include thenar muscle release, skin flap reconstruction, tendon transfers, and MP joint arthrodesis.

Can congenital hand contractures improve without surgery?

For mild cases of camptodactyly, conservative management like stretching and splinting can prevent progression and sometimes improve the contracture. However, many severe congenital contractures, especially in conditions like amyoplasia or severe clasped thumb, are rigid and often require surgical intervention for functional improvement.

What is the difference between flexible and fixed camptodactyly?

Flexible (reducible) camptodactyly allows for some passive extension of the PIP joint, whereas fixed (irreducible) camptodactyly has a permanent, unyielding flexion contracture. This distinction guides treatment planning, with flexible types being more amenable to nonoperative approaches.