Classification of congenital thumb hypoplasia and deformity

BackgroundCongenital thumb deformities account for one-third or more of all cases of congenital hand deformity. However, the current classification schemes of congenital thumb hypoplasia are no longer adequate due to their lack of adaptability to increasing knowledge in the field. Hence, a modified system with the potential to adapt to ongoing advances in knowledge and understanding is desperately needed.MethodsBased on the photographs collected from thousands of cases of congenital deformities of the hand and upper limb over multiple decades in our department, we subdivided thumb hypoplasia according to the variables of morphological characteristics, anatomical structures, functional status, the relationship between thumb deformity and hand deformity, the relationship between congenital hand deformity syndrome and thumb hypoplasia, and the selection of treatment methods.ResultsA total of 10 types were presented, which were elucidated with nomenclatures as well as pathological feature and symptoms.ConclusionThis modified system may shed additional light on the classification of congenital thumb anomalies, which will assist in a more effective selection of treatment modalities and offers significant benefits to both patients and practice.     

Surgical management of the Blauth 1 to 3A thumb hypoplasia

Thumb hypoplasia is a sequence of congenital abnormalities, from minor hypoplastic thumb with a preserved function to complete thumb aplasia. We only discuss in this chapter on the management of the thumb hypoplasia type 1 to 3A according to the modified Blauth's classification. Their common feature is the conservative treatment, in opposition with severe hypoplastic thumbs usually treated by index pollicisation. Whatever is the degree of hypoplasia, patients should be carefully examined for bilaterality, other anomalies and syndrome. Surgical treatment, when indicated, requires systematically widening of the first web space, stabilization of the metacarpophalangeal joint and restoration of opposition and extension. Reconstruction of the infant thumb should be started in the first year of life. Functional result depends on the degree of hypoplasia and differs dramatically whether if the thumb hypoplasia is isolated or associated with a radial club hand.     

Conduite à tenir devant une hypoplasie du pouce de type 1 à 3A

Thumb hypoplasia is a sequence of congenital abnormalities, from minor hypoplastic thumb with a preserved function to complete thumb aplasia. We only discuss in this chapter on the management of the thumb hypoplasia type 1 to 3A according to the modified Blauth’s classification. Their common feature is the conservative treatment, in opposition with severe hypoplastic thumbs usually treated by index pollicisation. Whatever is the degree of hypoplasia, patients should be carefully examined for bilaterality, other anomalies and syndrome. Surgical treatment, when indicated, requires systematically widening of the first web space, stabilization of the metacarpophalangeal joint and restoration of opposition and extension. Reconstruction of the infant thumb should be started in the first year of life. Functional result depends on the degree of hypoplasia and differs dramatically whether if the thumb hypoplasia is isolated or associated with a radial club hand.     

Characteristics of patients with hypoplastic thumb: a prospective study of 51 patients with the results of surgical treatment

The aim of this study was to characterize a group of patients with hypoplasia of the thumb, classifying them, describing the associated anomalies and to evaluate the results of surgical treatment of such cases. Thumb hypoplasia is a complex and heterogeneous congenital disorder that is detrimental to hand functions. The characteristics of patients with these anomalies are not well described in the literature. A prospective study on 51 patients with 82 hypoplastic thumbs was done. All the patients' data regarding their personal, family, pregnancy and developmental histories were recorded. All the patients were exposed to thorough clinical examination with genetic assessment and radiological examination including abdominal ultrasonography and echocardiography when requested by the paediatrician. The cases were classified using the modified Blauth classification into five types and we added the five-fingered hand. Surgical treatment was performed for 26 hands in 18 patients and the postoperative results were recorded with an average duration of follow-up of 38.6 months. Of the 51 patients, there was a positive consanguinity in 23.5%. Eighty-six per cent were found to have associated anomalies. Type V thumb hypoplasia was the most common type followed by type IV, with type I being the least common. All the patients' parents were satisfied with the results of surgical treatment and noticed improvement of the performance of the operated hands in the daily activities. We detected some anomalies that have never been described before or described as case reports only; such as lacunar skull, congenital facial palsy and toe amputation; we also described familial radial side dysplasia with variable presentation of congenital anomalies of the thumb in the families. In addition, we think that the five-fingered hand should be added to the classification of thumb hypoplasia. Our study agrees with the literature regarding the distribution of different types of hypoplasia of the thumb, the incidence of associated anomalies and the results of surgical treatment.     

The spectrum of radial longitudinal deficiency: a modified classification

The records of 119 patients with 196 extremities with radial longitudinal deficiency seen between 1923 and 1996 were reviewed. We propose a global classification system that includes the spectrum of pathology affecting the radial side of the extremity, including deficiency of the radius, carpal abnormalities, and hypoplastic thumbs. Radial deficiency could be classified for 181 extremities of 104 patients using this classification system. Type N has a normal length radius and a normal carpus with thumb hypoplasia, type O has a normal length radius and radial side carpal abnormalities, type 1 has more than 2 mm shortening of the radius, type 2 has a hypoplastic radius, type 3 has a partial radius with absence of the distal physis, and type 4 has complete absence of the radius. All patients had thumb hypoplasia. Eighty-two percent of extremities with thumb hypoplasia but no deficiency of the radius that were available for carpal bone classification had carpal anomalies, including absence, hypoplasia, and coalitions. All the extremities with type 1 radial deficiency had carpal anomalies. Carpal abnormalities could not be determined for types 2, 3, and 4 deficiency because most had a prior centralization. Proximal radioulnar synostosis or congenital dislocation of the radial head was seen in 44% of extremities with type 1 radial deficiency. This classification includes carpal anomalies and thereby links isolated thumb hypoplasia and deficiency of the radius into one system.     

Thumb duplication and contralateral thumb hypoplasia in infant of mother with diabetes

Uncontrolled maternal diabetes frequently results in congenital anomalies. This report describes an infant of a mother with diabetes born with thumb hypoplasia and contralateral thumb duplication without other associated anomalies. Maternal diabetes should be part of the etiologic differential diagnosis of thumb anomalies. The concomitant occurrence of thumb duplication and hypoplasia, apparently as a result of the same systemic insult, suggests a close relationship between hypoplasia and duplication.     

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.     

示指拇化治疗重度拇指发育不全

目的 介绍示指拇化治疗先天性重度拇指发育不全(ⅢB～V型)的手术方法.方法 对Ⅳ型(漂浮拇)2例、ⅢB型(腕掌关节缺如)2例采用示指拇化,将示指自掌骨部位转位重建拇指.结果 4例移位指全部存活.术后随访2～3年,虎口开大70°～90°,接近健侧.拇指掌指关节屈曲后可与所有手指对指,近指间关节活动度从0°至100～120°,远指间关节活动度从0°至90°.指端两点分辨觉同健侧,外观和功能满意.结论 采用示指转位治疗重度发育不全的拇指,外形和功能满意,克服了以往采用皮瓣和骨瓣移植的缺点,是一种实用而可取的方法,值得推广.     

The hypoplastic thumb

Thumb hypoplasia is part of a spectrum of radial longitudinal deficiencies involving the upper limb. Systemic involvement of other organ systems is not uncommon, thus requiring a team approach to management. Because of the variety of anatomic abnormalities associated with thumb hypoplasia, clinical and intraoperative evaluation of the thumb must be precise. Effective management of thumb hypoplasia requires an understanding of the embryology, epidemiology, classification, presentation, and management options. Management, which is primarily determined by the grade of thumb hypoplasia, may include nonsurgical techniques, reconstruction, pollicization, and, recently, microsurgical procedures.     

Congenital Absence of Flexor Pollicis Longus Tendon Without Associated Anomalies of Thumb Hypoplasia: A Case Report and Review of the Literature

In this paper, we report a case of a 14-year-old girl with congenital aplasia of the flexor pollicis longus tendon who had no other associated anomalies of thumb hypoplasia and no trauma history. Flexor pollicis longus tendon anomalies are rare; several types of this congenital anomaly have been reported in the literature. The diagnosis should be considered if a patient is unable to flex the interphalangeal joint of the thumb. A hypoplastic thumb or an absent interphalangeal joint crease may be a diagnostic feature in such cases. Besides physical examination, we also used direct radiography and magnetic resonance imaging to diagnose this rare congenital anomaly in our patient.     

Precision grip with congenital hypoplasty or hypofunction of the thumb

We tested the grip in four patients with congenital defects of the hand and either a hypoplastic thumb or a thumb with impaired inervation. Small objects were taken by a scissors grip between the fingers. In a hand with radial duction in the manus vara congenita, during strengthening of the wrist, the grip from the ulnar side between the fourth and fifth fingers was changed to the radial side between the second and third fingers. Large objects were gripped by all the three-phalanx fingers into the palm in a horizontal position. In case 4 with hypoplasia of the thumb grade IIIC by the classification of Blauth and Buck-Gramcko, we describe a transposition of the index finger to the site of the thumb and the hypoplastic thumb to the site of the index finger. It is obvious that the precision grip is affected by the thumb length and strengthening of the ulnar side of the wrist. We assume that the scissors grip is the earliest precision grip in the evolution of the primate hand.     

Pollicization of the index finger for radial hypoplasia

Background

Associated with anomalies such as VACTERL and Fanconi anemia, congenital hypoplasia of the thumb has a strong association with radial hypoplasia. The majority of patients have bilateral thumb underdevelopment, and those that have a unilateral deformity tend to have the right hand more commonly affected. In order to gain an opposable thumb, patients with a deficient carpometacarpal (CMC) joint, a floating thumb, or complete absence of the thumb can benefit with a thumb amputation and a translocation of the index finger (pollicization) to the thumb position. This video demonstrates the technical steps involved in performing a pollicization procedure in a patient with radial hypoplasia. The video is available electronically.

Methods

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008 (5). Informed consent was obtained from all individual participants included in the video. The authors declare that they have no conflict of interest.

Results

Pollicization allows for improved functional results in patients with radial hypoplasia.

Conclusions

This video has reviewed the essential steps in performing a pollicization procedure in patients with radial hypoplasia.

Electronic supplementary material

The online version of this article (doi:10.1007/s11552-014-9693-z) contains supplementary material, which is available to authorized users.     

Familial congenital hypoplasia of the thumb--report on a family

Congenital hypoplasia of the thumb is not a rare condition in clinical practice, but a familial occurrence of this condition is exceedingly rare. We report a family with familial congenital hypoplasia of the thumb. In three generations, five members were proved to be affected and another two were presumed to be affected. To our surprise, a younger sister of the propositus had tetralogy of Fallot and triphalangeal thumbs on both hands.     

Reconstruction of a congenitally absent flexor pollicis longus in an adult

Congenital absence of the flexor pollicis longus (FPL) is an unusual finding that is frequently associated with thumb hypoplasia. Isolated FPL absence is the rarest of the congenital thumb anomalies. The present article describes a patient with a congenitally absent FPL, and discusses the chosen method of reconstruction.     

Modified dorsal rotation advancement flap for release of the thumb web space

The dorsal rotational advancement flap described by Buck-Gramcko in 1998 is a good local flap for release of the thumb index web space. This paper describes a modification which broadens the apex of the flap and increases its length. This modification provides a long wide flap which releases the thumb index web space with suture lines far beyond the web. In addition, it provides a release of the palmar skin even when very tight in severe narrowing of the web. It is suitable for release of thumb-index syndactyly, severe narrowing of the web in thumb hypoplasia and congenital clasped thumb.     

Intercarpal degenerative arthritis in adulthood as a late consequence of unilateral congenital aplasia of the scaphoid: a case report

We report a case of unilateral congenital aplasia of the carpal scaphoid bone discovered in adulthood, which probably caused a severe painful intercarpal degenerative arthritis. This case was not associated with hypoplasia or aplasia of thenar and forearm muscles, abnormality of the skeleton of the thumb ray, absence of the sesamoid bones, hypoplasia of the forearm bones, as in cases reported in the literature; the only additional anatomic abnormality was a mild hypoplasia of the radial styloid. A surgical treatment (4-bone arthrodesis) has been performed to treat the advanced carpal collapse and the arthritis.     

Principalization of pollicization of the index finger in congenital absence of the thumb

After reviewing our experience with pollicization in congenital cases of thumb hypoplasia or aplasia, we found that classic techniques have several weak points concerning function and appearance. Abduction is frequently inadequate, and adduction is quite weak. Esthetically the thumb has a slender aspect, the web fold is absent, and the commissure looks more like a cleft. We tried to prioritize the issues to propose some technical modifications for improvement of function and appearance.     

Congenital radio-humeral synostosis. A case report

In a 7-month-old male infant with congenital radiohumeral synostosis and associated absent first metacarpal, floating thumb, and hypoplasia of the humerus, the synostosis was resected. Elbow motion was obtained and one year postoperatively there was no recurrence of the synostosis.     

Functional assessment after pollicisation

Nine children with congenital aplasia or hypoplasia of the thumb were treated by pollicisation of the index finger. Functional assessment was performed on average five years after surgery. It demonstrated normal sensation and a power grip, pinch grip and adductor grip of the thumb of 63%, 56% and 63% respectively of the unoperated hand. Efficient use of the hand increased after surgery and continued to improve for some years. The results indicate that pollicisation benefits hand function and should be performed early.