Groningen, The Netherlands
The term congenital deficiency is used for an absent extremity or part thereof.
A classification is meant to define and distinguish different anomalies from each other as much as possible. Different classifications have been published throughout the years. The most usable classification is based on missing parts of the skeleton. In this classification a distinction is made between transverse and paraxial deficiencies. In transverse deficiencies a complete extremity is absent or part thereof. In paraxial deficiencies a part is absent in the length axes parallel and distal to the elbow or knee. Paraxial deficiencies can be divided into preaxial (radial and tibial), postaxial (ulnar and fibular) and central (cleft hand and foot) deficiencies.
The term terminal is used if all parts of the extremity distal to a particular part are missing and the term intercalary is used if a part of the extremity between the trunk and hand or foot is missing. Four groups can be distinguished (Fig. 17.1):
Frantz-O’Rahilly classification of congenital deficiencies (Redrawn from: Frantz CH, O’Rahilly R. Congenital skeletal limb deficiencies. J Bone Joint Surg Am. 1961;43A:1202–4) modified from Hall CB, Brooks MB, Dennis JF. Congenital skeletal deficiencies of extremities. Classification and fundamentals of treatment. J Am Med Assoc. 1962;181:590–9. (a) Transverse terminal deficiencies: amelia of the right arm, incomplete hemimelia of the left arm and hemimelia of the left leg. (b) Transverse intercalary deficiencies: distal phocomelia of the left arm, complete phocomelia of the left leg. (c) Paraxial terminal deficiencies: radius aplasia of the right arm, ulnar aplasia of the left arm, tibial aplasia of the right leg and fibular aplasia of the left leg. Absent thumb and fingers. (d) Paraxial intercalary deficiencies: radius aplasia of the right arm, ulnar aplasia of the left arm, tibial aplasia of the right leg and fibular aplasia of the left leg. The hand and foot are complete
Transverse terminal deficiency
In a transverse terminal deficiency the extremity is normally developed down to the level of the absent part. The transverse terminal deficiency can vary from missing distal phalanges or a complete extremity. The transverse terminal deficiencies are named after the absent part. I.e. if the foot is absent the term apodia is employed (podos is Greek for foot, apodia is absence of one or both feet). In amelia the whole extremity is absent (melos is Greek for limb). The term congenital amputation is often used for terminal transverse deficiencies. This is incorrect because it involves a constructional deformity and that which is not present cannot be amputated (amputare is Latin for circumferentially cutting off). Congenital amputations are caused by an amnion band constriction in principle in a normal extremity.
Transverse intercalary deficiency
Hereby a whole segment is absent between the trunk on one side and the hand and foot on the other. For instance the foot is fixed to the pelvis and the rest of the leg is absent. This deficiency is further divided into a complete deficiency in which the hand and foot are fixed to the trunk, a proximal deficiency in which the upper arm or thigh is completely missing and the distal deficiency whereby the forearm or the lower leg is completely missing. The old term phocomelia is frequently used (phoke is Greek for seal and melos for limb; the direct translation is a seal limb). The anomaly whereby the proximal part of the thigh including or not including the hip is an anomaly which is referred to as a proximal focal femur deficiency, that can also be referred to as an incomplete proximal type of phocomelia.
Paraxial terminal deficiency
This involves a congenital complete or partial absence of one bone or piece of bone in the forearm (radius or ulna), or lower leg (fibula or tibia) with the adjacent rays or parts of the rays of the hand and foot.
A completely missing piece of bone is called aplasia, i.e. radius aplasia (a means not present and plassein is Greek for forms). If a piece of bone is partly absent then this is called hypoplasia as in the case of radius hypoplasia (hypo is Greek for too little or too short).
Paraxial intercalary deficiency
This involves congenitally complete or partial absence of one of the pieces of bone in the forearm (radius or ulna) or lower leg (tibia of fibula) in which the hand or foot are completely present.
This deficiency may be limited to a cleavage of hand or foot but may be so extensive missing the central three rays.
In 1 in 2000 births children miss an extremity or a part thereof. It involves the upper limb twice as often as the lower limb. If there are more absent parts in other limbs then one should consider the possibility of a syndrome.
In 100 children born with a congenital deficiency about 70 will miss an arm or a part thereof. In most cases it involves a terminal transverse deficiency. In 98 % of cases this is unilateral. In 2 or 3 of these 100 children the radius or ulna or part thereof is absent.
In 30 of 100 children it involves the lower extremity whereby in about 20 of the 30 cases the fibula or a part thereof is absent. In 4 of these 30 children there is a deficient proximal part of the femur whereby the femoral head may or may not be absent.
Absence of the Whole or Part of the Arm
Complaint: the arm or a part of the arm and/or the hand is absent.
Assessment: the arm or the end of the arm is absent. The remaining part is normally developed.
Differential diagnosis (Fig. 17.2):
Classification terminal transverse deficiencies of the upper extremity
Transverse terminal deficiency
Absence of the whole arm.
Absence of the hand, forearm and a part of the upper arm.
Absence of the hand and forearm
Absence of the hand and part of the forearm
Absence of the hand and wrist.
(a is Greek for none, cheir is hand)
Absence of the thumb and all the fingers and metacarpals.
(dactylos is Greek for finger)
Absence of the distal phalanx of the thumb and all the distal finger phalanges.
Explanatory note: transverse terminal deficiency. The most frequent terminal deficiency in the upper limb is whereby one third of the forearm is present (incomplete hemimelia). The length of the forearm in a newborn with an incomplete hemimelia is as a rule not more than 7 cm (Fig. 17.3) and in adults not more than 10 cm. Afunctional rudimentary remaining fingers may be present. Pro- and supination are as a rule possible.
Incomplete hemimelia of the left arm
Apart from cases where the mother has used Thalidomide (Softenon) during pregnancy (in the 1950s and 1960s), no cause can generally be found for unilateral terminal transverse deficiency. Only if there is a bilateral or multifocal terminal transverse deficiency may one consider autosomal recessive inheritance or a syndrome.
Supplementary assessment: X-rays of the involved arm if necessary.
Primary care treatment: the parents should be informed that there are prostheses available but that their child can usually function well without a prosthesis.
When to refer: before the age of 5 and 6 months.
Secondary care treatment: treatment is only necessary if the child is functionally limited because of the deficiency. Future prospects for an improvement in function is a prerequisite for treatment. Improvement in the appearance of the arm or hand must not be at the expense of function. In any event one waits until the child has sitting balance before prescribing an upper extremity prosthesis. As a rule this is at the age of 5 or 6 months. In the first instance a simple prosthesis with an artificial hand without grip function is prescribed (Fig. 17.4). One waits until 2 years of age before prescribing a myoelectric prosthesis (Fig. 17.5). Wearing an upper extremity prosthesis is dependent on the child. The attitude of the parents and others in the direct surroundings play a big role. Older children choose themselves whether to use or not use a prosthesis. One child may wear the prosthesis the whole day and another only for certain activities. Children with a long forearm stump use the prosthesis much less often than children with a short forearm stump. If the child is fitted with a prosthesis before the third year of age, then the chances of successful use are greater than in older children. Extensive operative corrections will preferably be carried out before 3 years of age, because after that a functional improvement becomes more difficult to achieve.
Forearm prosthesis with an artificial hand without grip function on the right side
Right forearm myoelectric prosthesis
These children will usually not accept a prosthesis. A prosthesis is experienced as unhandy and heavy (Fig. 17.6). Children with a bilateral amelia often develop formidable compensatory possibilities using their feet and toes. As a result they can often use their feet to eat, brush their teeth, write and operate a computer. Patients with a bilateral amelia can possibly benefit from an electrical shoulder exarticulation prosthesis.
Body powered shoulder exarticulation prosthesis for an amelia. In unilateral cases the energy required to move the prosthesis is produced by movements of the contralateral shoulder
Incomplete amelia or hemimelia
An upper arm prosthesis is given for cosmetic reasons and in order to be able to grip objects. Because there is no elbow, a special elbow hinge is necessary to allow the prosthesis to be fixed at a particular angle. This may be necessary in order to be able to hold particular objects against the body. When walking the elbow hinge must be mobile so that a natural swinging movement can be made. The upper arm prosthesis is heavier and has much less ease of operation compared to a forearm prosthesis. The functional possibilities of the prosthesis are limited and the prosthesis will be worn particularly for cosmetic reasons (Fig. 17.7).
Upper arm prosthesis
The elbow is stable and can as a rule be overextended to about 30° and has excellent flexion. One can prescribe a prosthesis with an artificial hand that has no grip function when the child has a good sitting balance (Fig. 17.4).
Body powered prostheses
After the age of 2 years one can choose for a prosthesis with a hook, which the child can open and close (Fig. 17.8). The prosthesis is ideally suitable for grabbing objects and holding them tight. One can choose a prosthetic hand instead of a hook. A prosthetic hand has more grip function and looks more natural than a hook. The objects to be gripped are less easily seen and more energy is required in order to open the hand than is the case with a hook prothesis (Fig. 17.9).
Lower arm prosthesis with a hook
Body powered lower arm prosthesis with an artificial hand
The energy required to open the prosthetic hook is provided by movement in the elbow or the contralateral shoulder. These two previously mentioned prostheses are called body powered prostheses because the patient has to provide the energy required to open and close the hook or the hand.
Myoelectrically powered prostheses
There are electrically powered prostheses (Fig. 17.5). The energy required to open and close the artificial hand is provided by a battery. Some electrical prostheses are operated with a pull switch. Other prostheses are operated through a myoelectrical signal from the skin. There is an alternating electrical signal on contracture of the flexors and extensors in the forearm. The myoelectrical hand can be hereby opened and closed. More concentration is required for gripping with a myoelectric prosthesis than with a bodily powered prosthesis.
As a rule a prosthesis is not useful in patients who have a forearm but no wrist or hand (Fig. 17.10). A prosthesis with a grip function would be longer than a normal arm because of technical reasons. Sometimes a prosthesis may be provided in an older child for cosmetic reasons. In bilateral cases and in blind children a so-called “Krukenberg procedure” can be carried out. Hereby the radius and ulna are operatively separated creating “chopsticks” (Fig. 17.11). The other side can be possibly fitted with a prosthesis with a grip function. One needs good eyesight in order to grip an object with such a prosthesis, because this does not allow “feeling”. A blind child cannot be fitted with such a prosthesis with a grip function for this reason.
Acheiria. A prosthesis is as a rule not useful in a patient with an absent wrist and hand
A Krukenberg procedure can be carried out with an absent wrist and hand. Hereby the radius and ulna are operatively separated creating sort of “chopsticks”
Hereby the thumb, all of the fingers and the metacarpals are absent. Just as in acheiria a prosthesis is as a rule not meaningful. Grip function can possibly be provided by a so-called opposition orthosis (Fig. 17.12).
Opposition orthesis in a patient in which the wrist is present but the rest of the hand is absent (adactylia)
If there is a transverse reduction defect of the distal phalanges of the fingers, the thumb and the fingers are shorter than normal, they can often move more or less normally. Often only small objects can be picked up. In order to allow the child to pick up and hold larger objects the soft tissues in the webspace between the thumb and index finger can be operatively widened.
Absence of the Whole Arm or Upper Arm or Forearm Between the Trunk and the Hand in Which Case the Elbow Joint Is Always Absent
Complaint: between the trunk and the hand the whole arm or the upper arm or forearm is absent. The hand is fixed directly or with the forearm onto the trunk or onto the upper arm.
Assessment: a complete segment is absent from the arm between the trunk and the hand. The joint ligaments are flaccid and as a result (passively) hypermobile. The elbow is always absent. The fingers may also be absent. The strength in the extremity is lessened (Fig. 17.13).
Distal phocomelia of the left arm. The forearm is absent, the hand is fixed to the upper arm and the fingers are absent
Differential diagnosis (Fig. 17.14):
Classification of intercalary transverse deficiencies (phocomelia) in the upper extremity (Redrawn from: Tachdjian MO. Tachdjian’s paediatric orthopaedics. 2nd ed. Philadelphia: Saunders Company; 1990)
Transverse intercalary deficiency (phocomelia)
The upper arm and forearm are absent. The hand is fixed to the shoulder girdle.
The upper arm is absent. The forearm is fixed to the shoulder girdle.
The forearm is absent. The hand is fixed to the upper arm.
Explanatory note: transverse intercalary deficiency (phocomelia). Nowadays the deformity is rarely seen except in patients born in the 1950s and 1960s, when pregnant women often received Thalidomide (Softenon).
Supplementary assessment: as a rule not necessary.
Primary care treatment: none.
When to refer: during the first 6 months of life.
Secondary care treatment: complete phocomelia. A shoulder exarticulation prosthesis can be prescribed for a complete phocomelia of the upper extremity.
Proximal and distal phocomelia
In these cases a prosthesis is usually not prescribed. The hand function is as a rule good in the proximal type. The results of an operative treatment to lengthen the arm in the proximal type or to improve shoulder stability are disappointing.
Abnormal Forearm and/or Hand
Complaint: the hand has an abnormal position and the thumb and/or some of the fingers are possibly absent.
Assessment: the hand may be completely normal in the case of a radial deviation. The thumb may be flaccid and/or small or completely absent. The styloid process of the ulna is prominent. The forearm is short and is possibly curved with the convex side on the ulnar side.
If there is an ulnar deviation the hand can be complete but fingers and/or the thumb may be absent, most often the ring and the little finger. The forearm is short and may be curved radially. In many cases the upper arm is also shortened. Also, if the forearm is curved convexly on the radial side with ulnar deviation of the hand, this does not usually lead to functional problems.
The radial head can be dislocated or fixed to the humerus or there may be an unstable elbow.
There may also be deficiencies in which only the thumb or one or several fingers are absent without forearm deformities.
Preaxial terminal and intercalary deficiency
radial hypoplasia or aplasia (radial clubhand)
Postaxial terminal and intercalary deficiency
ulnar hypoplasia and aplasia (ulnar clubhand)
cleft hand (ectrodactyly, splithand, lobster-claw hand)
Explanatory note: paraxial terminal, paraxial intercalary and central deficiency. In the classification of hypoplasia and aplasia of the radius and ulna no distinction is made between the presence or absence of a complete hand. Although in both cases the lower arm is involved, the deformities are very different (Table 17.1). The term cleft hand is used for a central deficiency.
Radial and ulnar hypoplasia and aplasia have very different aspects
Radial hypoplasia or aplasia
Ulnar hypoplasia or aplasia
1 in 100,000
1 in 500,000
Part of a syndrome
Type III unstable
Type IV synostosis
Thumb regularly absent
Variable absence of thumb and fingers
Radial hypoplasia and aplasia
This occurs in 1 in every 100,000 births. In 50 % of cases it is bilateral. It occurs just as frequently in boys and girls. The deformity is not inheritable. If the radius is completely or partly replaced with a connective tissue strand that does not grow with the ulna, then the ulna will be curved with a convexity on the ulnar side. The hand is positioned in radial deviation and the deformity is also known as a radial club hand. The thumb can be normal but can also be absent or flaccid. The deformity can be classified into four types (Fig. 17.15). This is a radius hypoplasia (type I, II and III), if the radius is partly present and if the radius is completely absent then one speaks of radial aplasia (type IV). Usually there are functional problems in the wrist but not in the elbow (Fig. 17.16). There is generally a reasonable function even in an extensive radial deviation.
Heikel’s classification for radial hypoplasia and aplasia. Hypoplasia and aplasia of the radius can be divided into four types. If the radius is partially absent then there is a radius hypoplasia (type I, II and III), if the radius is completely absent then this is radius aplasia (type IV). H humerus, R radius, U ulna, * connective tissue strand (Redrawn from: Heikel HV. Aplasia and hypoplasia of the radius: studies on 64 cases and on epiphyseal transplantation in rabbits with the imitated defect. Acta Orthop Scand. 1959;39:1–115)
(a) and (b): radial aplasia of the right forearm (Heikel type IV). There is an underdeveloped thumb. (c) Bilateral radial aplasia
Slight shortening of the distal part of the radius. The ulna is not curved. The epiphysis in the proximal part of the radius is normal. The epiphysis in the distal part of the radius is seen later and has less growth potential than normal. There is only a slight radial deviation in the hand with respect to the wrist. The mobility of the elbow and wrist is normal.
The radius is shortened more than in type I. The ulna is thickened and curved convexly to the ulnar side. The proximal and distal epiphysis of the radius are visualized later and the growth potential is less than normal. The hand has a slight radial deviation. The mobility of the elbow and the wrist is normal.
The radius is partly absent at the level of the proximal, central or distal part, which is the most frequent. The ulna is thickened, shortened and curved convexly to the ulnar side. The elbow function is mostly normal. The stability of the wrist joint is less because of the absent distal part of the radius. There is a severe radial deviation.
Completely absent radius (radius aplasia). This is the most frequent type (Fig. 17.16). The ulna is severely curved convexly on the ulnar side. There is a radial deviation of the hand which can be as much as 90°. There is a false joint between the hand and the radial side of the distal part of the ulna. The humerus and the clavicle are shorter and the scapula is usually smaller than normal. By the time the child has grown up the total length of the upper extremity is about 2/3 the length of the normal extremity. The thumb and first metacarpal are absent in more than 80 % of cases. The scaphoid and trapezium are absent in more than half of the patients and the lunatum, trapezoid and pisiform in 10 %.
The long head of the biceps muscle and the wrist extensors are absent or severely hypoplastic if the radius is completely absent. The finger extensors are present. If the thumb is absent then all the muscles associated with thumb mobility are not present. The radial nerve stops at the elbow and sensation is provided by an abnormal branch of the median nerve. The musculocutaneous nerve may be absent. The ulnar and median nerves are complete. The radial artery is usually rudimentary or absent.
The condition can be an isolated malformation but can also occur in combination with other deformities. It is part of a syndrome in 25 % of cases (Table 17.2).
Syndromes with radial hypoplasia or aplasia
Absence of the thumb is mostly seen in a hypoplasia or aplasia of the radius or ulna but may also be part of a syndrome (Table 17.3).
Syndromes with an absent thumb
Ulnar hypoplasia and aplasia
This is an anomaly that occurs in 1 in 500,000 births. It is usually unilateral but there are often anomalies in the contralateral hand, such as absent fingers. The anomaly occurs with the same frequency in boys and girls but is not inheritable. The radius will be curved with a convexity towards the radial side if the ulna has been completely or partly replaced with connective tissue which does not grow at the same rate as the radius. The anomaly can be classified into four types (Fig. 17.17). Some fingers may be absent, mostly the ring finger and little finger (Fig. 17.18), but sometimes the thumb and the index finger are absent. If the ulna is partly absent then one calls this ulna hypoplasia (type I and II) and if the ulna is completely absent an ulnar aplasia (type III and IV).
Bayne classification for ulnar hypoplasia and aplasia. If the ulna is partly present one refers to this as ulnar hypoplasia (type I and II) and if completely absent as ulnar aplasia (type III and IV). H humerus, R radius, U ulna, * connective tissue strand (Bayne LG, Klug MS. Long-term review of the surgical treatment of radial deficiencies. J Hand Surg Am. 1987;12:169–79)
Ulnar hypoplasia of the right arm with (a): absent ring finger and little finger. (b): the forearm and upper arm are short
Shortened ulna. The ulna is present but shortened. The radius is hardly curved and there is no or limited ulnar deviation of the hand (Fig. 17.19).
Ulnar hypoplasia type I in a 13 year old patient. The radius is slightly curved with the convexity towards the radial side
The distal part of the ulna is absent. The proximal part has a normal joint with the humerus. The radial head may have a normal articulation with the humerus but lateral and posterior dislocations also occur. The elbow is stable and mobile but however, particularly pro- and supination are limited. The radius is curved convexly to the radial side. The hand is deviated towards the ulnar side (Fig. 17.20).
(a) Ulnar hypoplasia type II. The radius is curved convexly to the ulnar side and there is ulnar deviation of the hand. (b) The distal part of the ulna is absent. The radial head is displaced laterally and posteriorly
This is the rarest type. The ulna is completely absent.
The child has an unstable elbow. The radius is straight because there is no rudimentary connective tissue strand in place of the ulna. The hand is not deviated towards the ulnar side.
The ulna is absent and the radius is fixed to the humerus (so-called humeroradial synostosis) (Fig. 17.21). Usually there is a rudimentary ulna and that limits length growth in the radius. The radius increasingly bends with a radial convexity and, above all, wedging of the distal radial epiphysis occurs causing an increase in the ulnar deviation of the hand. The length of the forearm remains limited to 2/3 of normal. In type IV in which the distal humeral epiphyseal growth is lacking, the final length of the upper arm will be four fifths of normal (the epiphyseal growth plate in the distal part of the humerus contributes 20 % to the humeral length growth).
(a) Ulnar aplasia type IV. (b) The ulna is absent. there is a humeroradial synostosis. (c) There are only two fingers
Other inborn errors that occur in combination with ulnar hypoplasia or aplasia are as a rule limited to the locomotor apparatus in contrast to the radius.