The hypoplastic thumb

A 23-year-old patient with bilateral hypoplastic thumbs and toes: A case report

Key Clinical Message

However, it is noteworthy that certain patients with minor functional limitations in their hand may have experienced undiagnosed thumb hypoplasia during their childhood years. These individuals may have successfully adapted to their condition without seeking medical intervention and may express a preference for nonintervention (as in this case).

Abstract

Thumb hypoplasia is a congenital underdevelopment of the thumb, accounting for 5%-15% of congenital hand disorders. It occurs equally among both genders and can affect both thumbs. The condition is categorized using Blauth's classification with Type I being the mildest form. We report a 23-year-old Syrian male presented with a bilateral restriction in opposition movement when using a pen or razor. Clinical examination and x-ray imaging revealed a bilateral Type I hypoplastic thumb with bilateral minimal hypoplasia of the toes. Despite the surgical treatment options available, the patient opted not to undergo surgery due to his adaptation to his condition. Hypoplastic thumb Type I is a congenital condition characterized by underdevelopment of the thumb. Bilateral thumb hypoplasia with toes hypoplasia is extremely rare. A full systemic evaluation should be done due to its associations with other syndromic manifestations and treatment options are discussed concerning the best functional outcomes and patient preferences.

Index Finger Pollicization for Hypoplastic Thumb: Surgical Technique

SUMMARY

Pollicization can be performed for secondary thumb reconstruction after traumatic injury or for primary thumb construction in cases of congenital thumb hypoplasia. Given the complexity of this operation, intimate familiarity with the involved anatomy and surgical principles is key to successful surgical outcomes. In this Video Plus article, the authors present a step-by-step approach to pollicization in case of Blauth type IIIB thumb hypoplasia.

Restoration of Five Digit Hand in Type III B & C Thumb Hypoplasia-A Game Changer in Surgical Management

Background  Hypoplasia of thumb is the second common congenital difference of the thumb, next only to duplication. It may occur as an isolated hand difference or as a part of radial longitudinal deficiency. In approximately 60% of these children, the radius shows hypoplasia. The incidence of thumb hypoplasia is one in 100,000 live births. In 50% of these children, the other hand will also have similar deficiency, although variable in severity. Hypoplasia of thumb has been classified into five major categories, according to the increasing severity of hypoplasia. Type III hypoplasia of thumb is characterized by skeletal hypoplasia involving the first metacarpal and carpometacarpal joint, absent intrinsic muscles and rudimentary extrinsic muscles. It was further subclassified into types A, B & C. Type III B, described by Manske and McCarroll, involves extensive deficiency of extrinsic and intrinsic musculature with aplasia of the metacarpal base. Type III C, described by Buck-Gramcko, has hypoplastic metacarpal head.

Methods  It is widely believed that reconstruction of Type III B & C hypoplastic thumb will not be functionally useful, and they are often included in the indications for pollicization in thumb hypoplasia. In India, we frequently come across parents, who are not willing to remove the hypoplastic digit. This forced us to find out a way to reconstruct the hypoplastic thumb into a functionally useful digit. We describe our surgical technique of reconstruction of hypoplastic thumbs and our experience in utilization of the technique in five children with Type III B & C hypoplasia of thumb. Carpometacarpal joint of thumb was reconstructed and stabilized with a toe phalangeal transfer in the first stage and an opponensplasty was done in the second stage to improve movement.

Results  In all the five operated children, our surgical technique yielded a stable thumb which was functional. The donor site morbidity was acceptable. The parents were satisfied with the appearance and functional improvement.

Conclusion  Surgical reconstruction of hypoplastic thumbs of Type III B & C is possible, and conversion of these poorly developed remnants into a useful digit by our surgical technique is a gamechanger in the management of thumb hypoplasia.

Reconstruction of A Type IIIB Hypoplastic Thumb with A Huber Opposition Transfer in A Five-Year-Old Girl: Redefining Surgical Treatment

Thumb hypoplasia, a congenital deficiency of bony and soft tissue of thumb, is often associated with systemic syndromes like Holt-Oram syndrome, and is the second most common thumb anomaly after duplicated thumb. It has traditionally been classified into six categories, which help guide treatment including reconstruction versus pollicization (transfer of the index finger to thumb). Amputation of the thumb and pollicization is the traditional treatment for a IIIB hypoplastic thumb. A five-year-old girl presented with a classic type IIIB hypoplastic thumb in which she has absent motor function, aplasia of the metacarpal, shortened first web space, and an unstable but present carpometacarpal (CMC) joint. Instead of amputation, the thumb was reconstructed by capsulodesis to stabilize the CMC joint, Huber Transfer Opponensplasty and abductor pollicis longus transfer to restore motor function, W-plasty to deepen the first web space, and distraction to lengthen the metacarpal. The patient tolerated the multi-stage reconstruction and bony distraction well. She was followed for one year postoperatively and has demonstrated a functional thumb. This case questions the surgical algorithm for hypoplastic thumbs and suggests a revised classification system for hypoplastic thumbs which would further divide class III based on not only the stability of the CMC joint but the presence or absence of the joint as well. We propose that amputation be reserved for type III hypoplastic thumbs in which the CMC joint is absent, (revised class IIIC) and reconstruction be attempted when the joint is present irrespective of stability (revised classes IIIA and IIIB).

Long-Term Outcomes of Huber Opposition Transfer for Augmenting Hypoplastic Thumb Function

PURPOSE

This study was conducted to report the functional outcomes of the Huber opposition transfer (abductor digiti minimi muscle) in types II and IIIA hypoplastic thumbs.

METHODS

Patients who had undergone a Huber opposition transfer with at least 5 years of follow-up were included in this study. There were 21 thumbs included; 12 returned for a detailed evaluation and 9 were included with a medical record review. Outcome measures included range of motion and pinch strength; Pediatric Outcomes Data Collection Instrument (PODCI) and Patient-Reported Outcomes Measurement Information System (PROMIS) scores were collected on those who could return. There were 15 type II and 6 type IIIA thumbs.

RESULTS

Range of motion was significantly less than normal for both the interphalangeal and the metacarpophalangeal joints. For the returning cohort, key and tripod pinch were 44% and 65% of normal. The median Kapandji score was 9 (range, 6-10). The PODCI scores were high for global, upper extremity function, happiness, and pain. The PROMIS scores were similar to normal, except for parent reports of physical function. For all included patients, there was a revision surgery rate of 22%, primarily related to persistent instability.

CONCLUSIONS

At a minimum 5-year follow-up, the Huber opposition transfer for types II and IIIA thumbs was shown to provide good subjective outcomes, despite limited range of motion and strength.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Long term functional outcomes after early childhood pollicization

STUDY DESIGN

Retrospective Cohort

INTRODUCTION

Important outcomes of polliciation to treat thumb hypoplasia/aplasia include strength, function, dexterity, and quality of life.

PURPOSE OF THE STUDY

To evaluate outcomes and examine predictors of outcome after early childhood pollicization.

METHODS

8 children (10 hands) were evaluated 3-15 years after surgery. Physical examination, questionnaires, grip and pinch strength, Box and Blocks, 9-hole pegboard, and strength-dexterity (S-D) tests were performed.

RESULTS

Pollicized hands had poor strength and performance on functional tests. Six of 10 pollicized hands had normal dexterity scores but less stability in maintaining a steady-state force. Predictors of poorer outcomes included older age at surgery, reduced metacarpophalangeal and interphalangeal range of motion, and radial absence.

DISCUSSION

Pollicization resulted in poor strength and overall function, but normal dexterity was often achieved using altered control strategies.

CONCLUSIONS

Most children should obtain adequate dexterity despite weakness after pollicization except older or severely involved children.

LEVEL OF EVIDENCE

IV.

Congenital Thenar Hypoplasia with Absent Radial Artery: A Case Report

The thenar eminence is made up of the intrinsic muscles of the hand that are responsible for complex movement and finite motor functions of the hand. The wasting of these muscles can be associated with various clinical conditions. Cavanagh syndrome is a rare, isolated congenital thenar hypoplasia with characteristic clinical, radiological, and electrophysiological features. Congenital absence of the radial artery is a rare anatomic variant. We report a case of a boy with isolated right-sided congenital thenar hypoplasia meeting the clinical and radiological characteristics of Cavanagh syndrome with concurrent absence of the right radial artery.

On the classification of congenital thumb hypoplasia

In 1937, Müller introduced the concept of a teratological sequence of thumb hypoplasia with increasing severity from mild deficiency, through severe deficiency, to thumb absence. Blauth subsequently detailed five specific grades. In 1992, Manske and McCarroll altered Blauth's classification such that Grade 3 was sub-divided into Grades 3A and 3B, according to a presence or absence of the proximal metacarpal. Buck-Gramcko added a Grade 3C in which there was only a remnant metacarpal head. This article investigates their publications and those of others to identify 'who said what' and clarify the definitions of grades of thumb hypoplasia. A modification of Blauth's classification is proposed, which retains the integrity of the concept of Müller and the skeletal and soft tissue grading of Blauth, but which also incorporates the disparate anomalies that may present in Grades 2 and 3 hypoplastic thumbs.

Study of non-syndromic thumb aplasia in six independent cases

OBJECTIVES

To report on six independent and isolated cases demonstrating thumb aplasia as an essentially limb-specific phenotype.

METHODS

The subjects were ascertained during 2011-2013 from six different geographic regions of Pakistan, and underwent detailed clinical and phenotypic examination.

RESULTS

The affected arms of patients had complete absence of first digital rays, medial inclinations of second and fifth fingers, narrowing of palms, missing carpals, and shortening of zeugopod. All the subjects were presented with isolated and sporadic limb deficiencies, and five had no family history of limb or any other malformation. Parental consanguinity was denied in majority of the cases. We present detailed phenotypic manifestation of thumb apalsia in these subjects.

CONCLUSION

Thumb aplasia markedly impairs the normal function of affected hand. Surgical procedures like pollicisation of the index finger should be employed to improve the quality of life of these subjects. There is so far no specific genetic factor known for isolated thumb aplasia, compromising an accurate genetic counseling. Collection of patients with similar phenotypic presentations could be useful in further molecular genetic investigations.

Anomalous course of the extensor pollicis longus with multiple absences of thumb muscles

We report a rare case of a 10-year-old girl with anomalous course of extensor pollicis longus (EPL) muscle, which exists with absence of thenar muscles and muscles in the 1st extensor compartment. Her chief complaint was severe atrophy on the right thenar eminence. On physical examination, there was no obvious functional abnormality on her right thumb. On magnetic resonance imaging, we found that the abductor pollicis brevis, opponens pollicis, abductor pollicis longus, and extensor pollicis brevis muscles were absent. The tendon of the EPL muscle was found, but it had abnormal insertion on the radial side of the proximal phalanx, not on the distal phalanx. This variation was thought to have played a major role in compensating for impaired abduction of the thumb, which is usually accompanied by agenesis of major abductors of the thumb.

Bipolar affective disorder associated with thenar hypoplasia: is lithium safe?

Thenar hypoplasia has been described to occur as a part of radial longitudinal deficiency syndromes and occasionally related to Holt-Oram syndrome in which both cardiac and skeletal abnormalities co-occur. We describe a case with bilateral thenar hypoplasia, which resembles a milder variety of Holt-Oram syndrome, who developed bradycardia after exposure to lithium at therapeutic doses.

Reconstruction of the hypoplastic thumb

Thumb hypoplasia is characterized by diminished thumb size, metacarpal adduction, metacarpophalangeal joint instability, thenar muscle hypoplasia or aplasia, extrinsic tendon dysplasia, and in the most severe cases, carpometacarpal joint instability or thumb aplasia. Severe thumb hypoplasia and aplasia are best treated by thumb ablation and pollicization of the index finger. Less severe thumb hypoplasia can be reconstructed by a combination of soft tissue release, first web space local flap coverage, metacarpophalangeal joint collateral ligament and capsule reconstruction, extrinsic tendon tenolysis, and muscle or tendon transfers.

Congenital anomalies of the hand: an overview

Of the 1% to 2% of newborns that are born with congenital defects, 10% of these are born with upper extremity malformations. Although many classification systems have been developed, the most widely used classification system was developed by Swanson. This system categorizes the congenital upper extremity malformations according to the embryonic process that has failed to develop. Congenital hand malformation is a broad category that is broken down into 7 subclasses. This review will focus on congenital hand defects and their associated craniofacial syndromes. The topics will include failure of formation, failure of differentiation, duplication, overgrowth, undergrowth, constriction band syndromes, and generalized skeletal abnormalities.

Thumb hypoplasia

Hypoplasia of the thumb refers to a spectrum of clinical abnormalities ranging from a slightly small digit to complete absence (or aplasia) of the thumb unit. As a component of radial dysplasia, thumb hypoplasia can be either an isolated entity or seen in conjunction with other elements of radial longitudinal deficiency. Treatment of this condition initially involves identifying and addressing co-morbid anomalies in other body systems. The severity of thumb hypoplasia is then graded so that appropriate treatment methods can be instituted. The goal of treatment is ultimately to provide the child with a stable and functional thumb unit.

Congenital thumb deformities and associated syndromes

Upper limb defects occur in approximately 3.4 per 10,000 live births. Major thumb defects represent 16% of these upper limb defects (Tay SC, Moran SL, Shin AY, et al. The hypoplastic thumb. J Am Acad Orthop Surg 2006;14:354-366). Embryologically, hand development begins by the fifth week. This occurs simultaneously with the growth and development of the cardiovascular, neurologic, and hematopoietic systems. Therefore, congenital anomalies seen in the hands of infants may indicate significant anomalies in these other systems, requiring a comprehensive physical evaluation. Although the cause of 40% to 50% of congenital hand anomalies is unknown (Gallant GG, Bora FW. Congenital deformities of the upper extremity. J Am Acad Orthop Surg 1996;4:163-171), several others have traced this to specific genetic mutations. Others are due to a variety of teratogenic effects (Sadler TW. Langman's Medical Embryology. 10th ed. Philadelphia: Lippincott Williams &Wilkins, Chapter 9, 2006:125-142). For the clinician, this paper has been organized to identify possible corresponding syndromes that may accompany specific thumb deformities.

Congenital thenar hypoplasia with absent radial artery--a case report

Cavanagh syndrome is a rare, isolated congenital thenar hypoplasia with characteristic clinical, radiological and electrophysiological features. It has never been reported to occur in association with absent radial artery. We report the case of a boy with left sided congenital thenar hypoplasia fulfilling the characteristic clinical, radiological and electrophysiological features of Cavanagh syndrome, associated with congenital absence of left radial artery. We also discuss the possible underlying aetiopathology of Cavanagh syndrome.

Reconstruction of the type IIIA hypoplastic thumb

The management of the hypoplastic thumb depends on the degree of bony malformation, soft tissue anomaly, and deficiencies. Type IIIA thumbs have thumb-index web-space narrowing, hypoplasia of the thenar musculature, metacarpophalangeal joint instability, and extrinsic tendon abnormalities. They also have a hypoplastic metacarpal with a stable carpometacarpal joint, differentiating them from type IIIB thumbs which have an unstable carpometacarpal joint due to partial metacarpal aplasia. Whereas type IIIB thumbs are best treated with ablation and index pollicization, type IIIA thumbs are amenable to reconstruction. Many techniques have been described for correction of the variety of deformities found in theses thumbs. The purpose of this article is to present our preferred technique for comprehensive reconstruction of type IIIA thumbs.