Three main points in diagnosing thumb hypoplasia are: width of the first web space, instability of the involved joints and function of the thumb. Thorough physical examination together with anatomic verification at operation reveals all the anomalies. An X-ray of the hand and thumb in two directions is always mandatory. When the pediatrician thinks the condition is associated with some kind of syndrome other tests will be done. More subtle manifestations of types I and II may not be recognized, especially when more obvious manifestations of longitudinal radial deficiency in the opposite extremity are present. Therefore, a careful examination of both hands is important.

There are multiple classifications for the triphalangeal thumb. The reason for these different classifications is the heterogeneity in appearance of the TPT.

The classification according to Wood describes the shape of the extra phalanx: delta (Fig. 4), rectangular or full phalanx (Table 1). With the classification made by Buck-Gramcko a surgical treatment can be chosen (Table 1). Buck-Gramcko differentiates between six different shapes of the extra phalanx and associated malformations.

Table 1: Classifications of Wood and Buck-Gramcko

When it comes to treatment it is important to differentiate a thumb that needs stability, more web width and function, or a thumb that needs to be replaced by the index finger. Severe thumb hypoplasia is best treated by pollicization of the index finger. Less severe thumb hypoplasia can be reconstructed by first web space release, ligament reconstruction and muscle or tendon transfer.

It has been recommended that pollicization is performed before 12 months, but a long-term study of pollicizations performed between the age of 9 months and 16 years showed no differences in function related to age at operation.

It is important to know that every reconstruction of the thumb never gives a normal thumb, because there is always a decline of function. When a child has a good index finger, wrist and fore-arm the maximum strength of the thumb will be 50% after surgery in comparison with a normal thumb. The less developed the index finger, wrist and fore-arm is, the less strength the reconstructed thumb will have after surgery.

There are several classifications for cleft hand, but the most used classification is described by Manske and Halikis see table 3. This classification is based on the first web space. The first web space is the space between the thumb and the index.

Table 3: Classification for cleft hand described by Manske and Halikis

The goals of surgical treatment are: reducing length of the thumb, creating a good functioning, a stable and non deviated joint and improving the position of the thumb if necessary. Hereby improving function of the hand and thumb.

In general the surgical treatment is done for improvement of the thumb function. However, an extra advantage of the surgery is the improvement in appearance of the thumb. In the past, surgical treatment of the triphalangeal thumb was not indicated, but now it is generally agreed that operative treatment improves function and appearance. Because an operation was not indicated in the past, there’s still a population with an untreated triphalangeal thumb. The majority of this population doesn’t want surgery, because the daily functioning of the hand is good. The main obstacle for the untreated patients might not be the diminished function, but the appearance of the triphalangeal thumb.

The timing of surgery differs between Wood and Buck-Gramcko. Wood advises operation between the age of six months and two years, while Buck-Gramcko advises to operate for all indications before the age of six years.

- For TPT types I and II of the Buck-Gramcko classification, the surgical treatment typically consists of removing the extra phalanx and reconstructing the ulnar collateral ligament and the radial collateral ligament if necessary.

- For type III of Buck-Gramcko classification proposable surgical treatments:

- For type IV of Buck-Gramcko classification the surgical treatment typically consists of an osteotomy which reduces the middle phalanx and arthrodesis of the DIP. This gives a shortening of 1 to 1.5 cm. In most cases, this technique is combined with a shortening, rotation and palmar abduction osteotomy at metacarpal level to correct for position and length of the thumb. The extensor tendons and the intrinsic muscles are shortened as well.

- For type V of the Buck-Gramcko classification the surgical treatment proposably consists of a "pollicization". With a pollicization the malpositioned thumb is repositioned, rotated and shortened, the above-described rotation reduction osteotomy of the first metacarpal can be performed as well.

- For type VI of the Buck-Gramcko classification, the surgical treatment typically consists of removing the additional mostly hypoplastic thumb(s). Further procedures of reconstruction of the triphalangeal thumb are performed according to the shape of the extra phalanx as described above.

Because neither of the two thumb components is normal, a decision should be taken on combining which elements to create the best possible composite digit. Instead of amputating the most hypoplastic thumb, preservation of skin, nail, collateral ligaments and tendons is needed to augment the residual thumb. Surgery is recommended in the first year of life, generally between 9 and 15 months of age.

Surgical options depend on type of polydactyly.

There are a few different classifications conceived to categorize the spectrum of variety of congenital clasped thumb. In literature X classifications have been described for clasped thumb. The two most relevant of the existing classifications, to our opinion, are the classifications of McCarrol and Tjuyuguchi et al.

The most global format is the classification of McCarrol, which divides the congenital clasped thumbs into two groups. Group I includes the supple clasped thumb, when the thumb is only passively correctable. While complex clasped thumbs, thumbs which cannot be moved neither passively or actively, belong to group II.

Tjuyuguchi et al. designed a classification existing of three groups:

- Group I: The supple clasped thumb, where the thumb is passively abductable and extendable against the resistance of thumb flexors, without other digital anomalies.

- Group II: The clasped thumb with hand contractures, where the thumb is not passively extendable and abductable, with or without other digital anomalies.

- Group III: The clasped thumb which is associated with arthrogryposis.

This type of procedure is recommended for Wassel types 1 and 2 (in which both thumbs are severely hypoplastic) by some congenital hand surgeons. The technique contains a composite wedge resection of the central bone and soft-tissue. This will be achieved with approach of the lateral tissue of each thumb. The goal is to achieve a normal thumb, what concerns the size, which is possible. If the width of the nail bed is greater than 70% of the contralateral thumb, it may be split. Then the nail bed will be repaired precisely.

Surgical treatment of the cleft hand is based on several indications:

Improving function

- Absent thumb

- Deforming syndactyly (mostly between digits of unequal length like index and thumb)

- Transverse bones (this will progress the deformity; growth of these bones will widen the cleft)

- Narrowed first webspace

- The feet

Aesthetical aspects

- Reducing deformity

There is no standard treatment for the hand malformations in Apert due to the differences and severity in clinical manifestations in different patients. Every patient should therefore be individually approached and treated, aiming at an adequate balance between hand functionality and aesthetics.

However, some guidelines can be given depending on the severity of the deformities.

In general it is initially recommended to release the first and fourth interdigital spaces, thus releasing the border rays.

This makes it possible for the child to grasp things by hand, a very important function for the child's development. Later the second and third interdigital spaces have to be released.

Because there are three handtypes in Apert, all with their own deformities, they all need a different approach regarding their treatment:

- Type I hand usually needs only the interdigital web space release. First web release is rarely needed but often its deepening is necessary. Thumb clynodactyly correction will be needed.

- In type II hands it is recommended to release the first and fifth rays in the beginning, then the second and the third interdigital web spaces have to be freed. The clynodactyly of the thumb has to be corrected as well. The lengthening of the thumb phalanx may be needed, thus increasing the first web space. In both type I and type II, the recurrent syndactyly of the second web space will occur because of a pseudoepiphysis at the base of the index metacarpal. This should be corrected by later revisions.

- Type III hands are the most challenging to treat because of their complexity. First of all, it is advised to release the first and fourth webspace, thus converting it to type I hand. The treatment of macerations and nail-bed infections should also be done in the beginning. For increasing of the first web space, lengthening of the thumb can be done. It is suggested that in severe cases an amputation of the index finger should be considered. However, before making this decision, it is important to weigh the potential improvement to be achieved against the possible psychological problems of the child later due to the aesthetics of the hand. Later, the second and/or third interdigital web space should be released.

With growing of a child and respectively the hands, secondary revisions are needed to treat the contractures and to improve the aesthetics.

Diagnosis of a trigger thumb is solely made by these clinical observations and further classified into four stages:

Treatment of congenital clasped thumb includes two types of therapy: conservative and surgical.

Omphalocele has been described in two patients with Apert syndrome by Herman T.E. et al. (USA, 2010) and by Ercoli G. et al. (Argentina, 2014). An omphalocele is a birth defect in which an intestine or other abdominal organs are outside of the body of an infant because of a hole in the bellybutton area. However, the association between omphalocele and Apert syndrome is not confirmed yet, so additional studies are necessary.

Diagnosis is based on physical examination including radiographs of the hands and feet and imaging studies of the kidneys, bladder, and female reproductive tract. HOXA13 is the only gene known to be associated with HFGS. Approximately 60% of mutations are polyalanine expansions. Molecular genetic testing is clinically available.

Research on prenatal diagnosis has shown that a diagnosis can be made prenatally in approximately 50% of fetuses presenting arthrogryposis. It could be found during routine ultrasound scanning showing a lack of mobility and abnormal position of the foetus. Nowadays there are more options for visualization of details and structures can be seen well, like the use of 4D ultrasound. In clinic a child can be diagnosed with arthrogryposis with physical examination, confirmed by ultrasound, , or muscle biopsy.

In cases of a minor deviation of the wrist, treatment by splinting and stretching alone may be a sufficient approach in treating the radial deviation in RD. Besides that, the parent can support this treatment by performing passive exercises of the hand. This will help to stretch the wrist and also possibly correct any extension contracture of the elbow. Furthermore, splinting is used as a postoperative measure trying to avoid a relapse of the radial deviation.

Synpolydactyly is a joint presentation of syndactyly (fusion of digits) and polydactyly (production of supernumerary digits). This is often a result of a mutation in the HOX D13 gene.

Types include:

Many other surgeries are also able to improve function in joints of arthrogryposis patients. These surgeries usually exist out of tendon transfers and skin flap movements, adjusted to the individual.

There are several types of treatment for congenital trigger thumb, conservative and surgical.

Additional findings that may be present in HFGS according to the latest research are:

- Limited metacarpophalangeal flexion of the thumb or limited ability to oppose the thumb and fifth finger

- Hypoplastic thenar eminences

- Medial deviation of the great toe (hallux varus), a useful diagnostic sign when present

- Small great toenail

- Fifth-finger clinodactyly, secondary to a shortened middle phalanx

- Short feet

- Altered dermatoglyphics of the hands; when present, primarily involving distal placement of the axial triradius, lack of thenar or hypothenar patterning, low arches on the thumbs, thin ulnar loops (deficiency of radial loops and whorls), and a greatly reduced ridge count on the fingers

Radiographic findings

- Hypoplasia of the distal phalanx and first metacarpal of the thumbs and great toes

- Pointed distal phalanges of the thumb

- Lack of normal tufting of the distal phalanges of the great toes

- Fusions of the cuneiform to other tarsal bones or trapezium-scaphoid fusion of the carpals

- Short calcaneus

- Occasional bony fusions of the middle and distal phalanges of the second, third, fourth, or fifth toes

- Delayed carpal or tarsal maturation

- Metacarpophalangeal profile reflecting shortening of the first metacarpal, the first and second phalanges, and the second phalanx of the second and fifth digits

Urogenital Defects

Females may have the following:

- Vesicoureteral reflux secondary to ureteric incompetence

- Ectopic ureteral orifices

- Trigonal hypoplasia

- Hypospadiac urethra

- Subsymphyseal epispadias

- Patulous urethra

- Urinary incontinence (related to structural anomalies and weakness of the bladder sphincter muscle)

- Small hymenal opening

- Various degrees of incomplete Müllerian fusion with or without two cervices or a longitudinal vaginal septum

Males may have the following:

- Retrograde ejaculation (related to structural anomalies and weakness of the bladder sphincter muscle)

More severe types (Bayne type III en IV) of radial dysplasia can be treated with surgical intervention. The main goal of centralization is to increase hand function by positioning the hand over the distal ulna, and stabilizing the wrist in straight position. Splinting or soft-tissue distraction may be used preceding the centralization.

In classic centralization central portions of the carpus are removed to create a notch for placement of the ulna. A different approach is to place the metacarpal of the middle finger in line with the ulna with a fixation pin.

If radial tissues are still too short after soft-tissue stretching, soft tissue release and different approaches for manipulation of the forearm bones may be used to enable the placement of the hand onto the ulna. Possible approaches are shortening of the ulna by resection of a segment, or removing carpal bones. If the ulna is significantly bent, osteotomy may be needed to straighten the ulna. After placing the wrist in the correct position, radial wrist extensors are transferred to the extensor carpi ulnaris tendon, to help stabilize the wrist in straight position. If the thumb or its carpometacarpal joint is absent, centralization can be followed by pollicization. Postoperatively, a long arm plaster splinter has to be worn for at least 6 to 8 weeks. A removable splint is often worn for a long period of time.

Radial angulation of the hand enables patients with stiff elbows to reach their mouth for feeding; therefore treatment is contraindicated in cases of extension contracture of the elbow. A risk of centralization is that the procedure may cause injury to the ulnar physis, leading to early epiphyseal arrest of the ulna, and thereby resulting in an even shorter forearm. Sestero et al. reported that ulnar growth after centralization reaches from 48% to 58% of normal ulnar length, while ulnar growth in untreated patients reaches 64% of normal ulnar length. Several reviews note that centralization can only partially correct radial deviation of the wrist and that studies with longterm follow-up show relapse of radial deviation.

Evaluations by certain specialists should be performed following the initial diagnosis of Duane-radial ray syndrome. These evaluations will be used to determine the extent of the disease as well as the needs of the individual.

- Eyes - Complete eye exam by an ophthalmologist especially focusing on the extraocular movements of the eye and the structural eye defects

- Heart - evaluation by a cardiologist along with an echocardiogram and ECG

- Kidneys - Laboratory tests to check kidney function and a renal ultrasound

- Hearing

- Endocrine - evaluation for growth hormone deficit if growth retardation present

- Blood - CBC to check for thrombocytopenia and leukocytosis

- Clinical genetics consultation

MRI imaging can be used to detect whether the abducens nerve is present.

CMC OA is diagnosed based on clinical findings and radiologic imaging.

Patients with abnormal cardiac and kidney function may be more at risk for hemolytic uremic syndrome