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THUMB-IN-PALM DEFORMITY (CLASPED THUMB)

Introduction

Thumb-in-palm deformity (clasped thumb) is a rare, progressive flexion and adduction deformity. Essentially, the thumb’s extensor tendon mechanism is deficient, or one or more of the extensor tendons is absent. The disorder is usually bilateral and has a familial tendency. The diagnosis is frequently delayed, because the thumb is naturally in the palm from birth to approximately 3 months of age. Once the child begins to use the thumb for grasping, the persistent flexion and adduction becomes obvious. The deformity impairs grasp-release and pinch functions.  The most common cause of thumb-in-palm deformity is cerebral palsy.

Pathophysiology

  • About one-third of cases are genetically sporadic.
  • There is a high percentage of positive consanguinity and family history.
    • Tsuyuguchi classification:*
      • Type I, flexible: thumb can be passively extended, with no other abnormality
      • Type II, comorbidity: thumb cannot be passively abducted or extended, and there are collateral ligament or thenar muscle abnormalities
      • Type III, joint contractures: features of type II are present along with arthrogryposis

* Several classifications are commonly used. The House classicication defines four types of thumb-in-palm.3

 Related Anatomy

  • In thumb-in-palm (TIP) deformity:
    • Flexion adduction muscles of the thumb are the common primary deforming force
    • Extension abduction muscles of the thumb are weak or have poor voluntary control
    • Mobility at the interphalangeal (IP) joint may be unaffected
    • Mobility problems occur in the thumb CMC joint, the metacarpophalangeal (MP) joint and the thumb IP joint.
    • All nine muscles that contribute to normal thumb motor function can be part of motor imblaance that produces a thumb-in-palm deformity.
    • Laxity of the ulnar collateral ligament and the volar plate of the thumb MP joint may also be observed in thumb-in-palm deformity.

Incidence and Related Conditions

  • Thumb-in-palm deformiy (TIP) is generally not isolated, but presents with a broad range of other musculoskeletal malformations, such as cerebral palsy, arthrogryposis, digitotalar dysmorphism, and Freeman–Sheldon syndrome.
  • A variety of anomalies such as webbing, cleft palate, and ventricular septal defect also may be present.
  • Thumb-in-palm deformiy (TIP) is one of several common manifestations of cerebral palsy.

Differential Diagnosis

  • Arthrogryposis
  • Cerebral palsy
  • Digitotalar dysmorphism
  • Dundar syndrome
  • Freeman–Sheldon syndrome
  • MASA syndrome
  • Trigger thumb
  • Traumatic brain injury
  • Cerebral Vascular Accident (CVA)
ICD-10 Codes

  • CLASPED THUMB

    Diagnostic Guide Name

    CLASPED THUMB

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    CLASPED THUMBQ68.1   

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
  • Thumb-in-palm (Clasped Thumb) secondary to cerebral palsy
    Thumb-in-palm (Clasped Thumb) secondary to cerebral palsy
  • Thumb-in-palm (Clasped Thumb) secondary to traumatic brain injury
    Thumb-in-palm (Clasped Thumb) secondary to traumatic brain injury
  • Thumb-in-palm (Clasped Thumb) secondary to stroke
    Thumb-in-palm (Clasped Thumb) secondary to stroke
Symptoms
Poor pinch
Pain with thumb use
Presence of other musculoskeletal syndromes and anomalies
Limited grasp caused by the fingers flexing over the thumb in the palm
Typical History

The patient is usually a child 1–2 years old brought for examination due to flexed and adducted thumbs preventing grasping of objects. There may be a family history of clasped-thumb deformity, or of other anomalies (eg, CP, club feet, windblown deformity of the hands). 

Positive Tests, Exams or Signs
Work-up Options
Treatment Options
Treatment Goals
  • Increase thumb function
  • Improve Pinch
  • Improve grasp
Conservative
  • Splinting and physical therapy in type I deformities and in patients who only have extensor tendon weakness
  • Botulinum toxin injections (mild cases)
  • Conservative treatment is not recommended in patients with severe hypoplasia or agenesis 
Operative
  • Surgery is recommended for patients with tendon hypoplasia or absence, late presentation, and contracture at first web space
  • If delaying surgery is mandatory, then splinting should be performed to decrease severity of contractions, which can cause progression of deformity
  • Tendon transfers: useful in patients with a hypermobile thumb with both extensor and opponens tendon deficiency
    • Extensor indicis proprius tendon transfer and simple z-plasty reconstruction of first web space
    • Transfer is followed by fixation with a K-wire for about 6 weeks
    • Splinting for 6 months and physical therapy
  • Releases:
    • Adductor release in palm
    • First dorsal interosseous release
    • Flexor pollicis brevis (thenars) release
  • Joint stabilization:
    • Carpometalcarpal, IP, or MP joint arthrodesis
    • MP joint volar capsulodesis

SURGICAL COMPLICATIONS2

  • Muscle imbalance is common after the surgery, particularly in growing children.
  • The deformity can reoccur if surgery is performed between 7–10 years of age.
  • Over- or under-correction can occur if all of the deforming forces across the joint are not addressed.
  • Contractures or adhesions can result from prolonged immobilization. 
Complications
  • Muscle imbalance is common after the surgery, particularly in growing children. 
  • The deformity can reoccur if surgery is performed between 7–10 years of age. 
  • Over- or under-correction can occur if all of the deforming forces across the joint are not addressed. 
  • Contractures or adhesions can result from prolonged immobilization. 
Outcomes
  • Success of treatment depends on the lesion type.
  • Conservative methods achieve good results in Tsuyuguchi type I and type II.
  • Splinting and physical therapy: very successful in specific cases
  • Tendon transfer: cosmetic and functional result can be excellent, with full mobility and much-improved grasping power
  • Joint arthrodesis: stabilization good to excellent  
Key Educational Points
  • Thumb-in-palm deformity (TIP) is the most complex problem of the upper extremity in patients with cerebral palsy.
  • Because TIP deformity can manifest in a variety of ways in patients with cerebral palsy, individualized assessment and treatment are necessary.
  • Pediatric trigger thumb appears quite similar, but treatment is vastly different; therefore, it is imperative to accurately differentiate the two disorders.
  • While pediatric trigger thumb is typically unilateral, TIP tends to be bilateral.
  • A trigger-thumb release procedure in a patient with TIP deformity is likely to worsen the flexion and adduction deformity and lead to a boutonnière posture.
References

New Article

  1. Alewijnse JV, Smeulders MJ, Kreulen M. Short-term and long-term clinical results of the surgical correction of thumb-in-palm deformity in patients with cerebral palsy. J Pediatr Orthop 2015;35(8):825-30. PMID: 25575357
  2. Van Heest AE. Surgical technique for thumb-in-palm deformity in cerebral palsy. J Hand Surg Am 2011;36:1526–31. PMID: 21816546
  3. House JH, Gwathmey FW, Fidler MO. A dynamic approach to the thumb-in-palm deformity in cerebral palsy. J Bone Joint Surg Am 1981; 63A: 216-2225. PMID: 7462278

Reviews

  1. Basu AP, Pearse J, Kelly S, et al. Early intervention to improve hand function in hemiplegic cerebral palsy. Front Neurol 2015;5:281 Epub. PMID: 25610423
  2. Van Heest AE. Surgical technique for thumb-in-palm deformity in cerebral palsy. J Hand Surg Am 2011;36:1526–31. PMID: 21816546

Classics

  1. Manske PR. Redirection of extensor pollicis longus in the treatment of spastic thumb-in-palm deformity. J Hand Surg Am 1985;10(4):553-60. PMID: 4020069
  2. Matev I. Surgical treatment of spastic thumb-in-palm deformity. J Bone Joint Surg 1963;45B(4): 703-8. PMID: 14074317
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