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.

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.

For most cases the diagnosis for congenital amputation is not made until the infant is born. One procedure that is helpful in determining this condition in an infant is an ultrasound examination of a fetus when still in the mother's abdomen as it can reveal the absence of a limb. However, since ultrasounds are routine they may not pick up all the signs of some of the more subtle birth defects.

The most popular method of treatment for congenital amputation is having the child be fit for a prosthesis which can lead to normal development, so the muscles don't atrophy. If there is congenital amputation of the fingers, plastic surgery can be performed by using the big toe or second toes in place of the missing fingers of the hand.

In rare cases of amniotic banding syndrome, if diagnosed "in utero", fetal surgery may be considered to save a limb which is in danger of amputation.

Studies suggest that prenatal care for mothers during their pregnancies can prevent congenital amputation. Knowing environmental and genetic risks is also important. Heavy exposure to chemicals, smoking, alcohol, poor diet, or engaging in any other teratogenic activities while pregnant can increase the risk of having a child born with a congenital amputation. Folic acid is a multivitamin that has been found to reduce birth defects.

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.

The complete or partial absence of the pectoralis muscle is the malformation that defines Poland Syndrome. It can be treated by inserting a custom implant designed by CAD (computer aided design). A 3D reconstruction of the patient's chest is performed from a medical scanner to design a virtual implant perfectly adapted to the anatomy of each one. The implant is made of medical silicone unbreakable rubber. This treatment is purely cosmetic and does not make up for the patient's imbalanced upper body strength.

The Poland syndrome malformations being morphological, correction by custom implant is a first-line treatment. This technique allows a wide variety of patients to be treated with good outcomes. Poland Syndrome can be associated with bones, subcutaneous and mammary atrophy: if the first, as for pectus excavatum, is successfully corrected by a custom implant, the others can require surgical intervention such as lipofilling or silicone breast implant, in a second operation.

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.

The timing of surgical interventions is debatable. Parents have to decide about their child in a very vulnerable time of their parenthood. Indications for early treatment are progressive deformities, such as syndactyly between index and thumb or transverse bones between the digital rays. Other surgical interventions are less urgent and can wait for 1 or 2 years.

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

No surgical outcomes studies exist for evaluating the function of the thumbs after an on-top plasty reconstruction.

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

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.

The surgery takes place under general anaesthesia and lasts less than 1 hour. The surgeon prepares the locus to the size of the implant after performing a 8-cm axillary incision and inserts the implant beneath the skin. The closure is made in 2 planes.

The implant will replace the pectoralis major muscle, thus enabling the thorax to be symmetrical and, in women, the breast as well. If necessary, especially in the case of women, a second operation will complement the result by the implantation of a breast implant and / or lipofilling.

Lipomodelling is progressively used in the correction of breast and chest wall deformities. In Poland syndrome, this technique appears to be a major advance that will probably revolutionize the treatment of severe cases. This is mainly due to its ability to achieve previously unachievable quality of reconstruction with minimal scaring.

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.

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

The cause of fibular hemimelia is unclear. Purportedly, there have been some incidents of genetic distribution in a family; however, this does not account for all cases. Maternal viral infections, embryonic trauma, teratogenic environmental exposures or vascular dysgenesis (failure of the embryo to form a satisfactory blood supply) between four and seven weeks gestation are considered possible causes.

In an experimental mouse model, change in the expression of a homeobox gene led to similar, but bilateral, fibular defects.

Fibular hemimelia or longitudinal fibular deficiency is "the congenital absence of the fibula and it is the most common congenital absence of long bone of the extremities." It is the shortening of the fibula at birth, or the complete lack thereof. In humans, the disorder can be noted by ultrasound in utero to prepare for amputation after birth or complex bone lengthening surgery. The amputation usually takes place at six months with removal of portions of the legs to prepare them for prosthetic use. The other treatments which include repeated corrective osteotomies and leg-lengthening surgery (Ilizarov apparatus) are costly and associated with residual deformity.

The incidence of VACTERL association is estimated to be approximately 1 in 10,000 to 1 in 40,000 live-born infants. It is seen more frequently in infants born to diabetic mothers. While most cases are sporadic, there are clearly families who present with multiple involved members.

While there is no cure for BGS, symptoms can be treated as they arise. Surgery shortly after birth can repair craniosynostosis, as well as defects in the hand to create a functional grasp. There are risks associated with untreated craniosynostosis, therefore surgery is often needed to separate and reshape the bones. Since patients with a RECQL4 mutation may be at an increased risk of developing cancer, surveillance is recommended.

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.

Diagnosis depends on the clinical scenario. However, karyotyping is an essential test for diagnosis.

In the above brachydactyly syndromes, short digits are the most prominent of the anomalies, but in many other syndromes (Down syndrome, Rubinstein-Taybi syndrome, etc.), brachydactyly is a minor feature compared to the other anomalies or problems comprising the syndrome.

Cenani–Lenz syndactylism, also known as Cenani–Lenz syndrome or Cenani–syndactylism, is an autosomal recessive congenital malformation syndrome involving both upper and lower extremities.

The syndrome is named after Turkish (Asim Cenani) and German (Widukind Lenz) medical geneticists.

It is sometimes possible to correct the problem with surgery, though this has high failure rates for treatment of post-traumatic radioulnar synostosis.