Friday, November 16, 2012

Grasp


download bonefeed an ios app

from
Proc (Bayl Univ Med Cent). 2000 October; 13(4): 343–348.
PMCID: PMC1312228

Grasp

Adrian E. Flatt, MD, FRCS, FACScorresponding author1
Author information ► Copyright and License information ►
In seeking a short, sharp title for this essay, I vacillated between grip and grasp. When consulting Dr. Dorland's Dictionary, I was surprised to find the primary definition of grip was “French, grippe influenza.” I therefore chose grasp, even though it does not appear in the good doctor's dictionary.
Despite the fact that the skeletal and muscular elements of the human hand are very nearly matched in many species, praise of our own human hand and its abilities is a very natural human weakness. In fact, the history of human civilization is replete with special studies of the hand. Galen (AD 129–199) devoted a large part of his De Usu Partium to the anatomy and physiology of the hand. Throughout the centuries, mystical properties have been imputed to the hand, and many gullible people have had their lives directed by the pronouncements of palmists.
Sir Charles Bell, in the first chapter of his fascinating fourth Bridgewater treatise—written >160 years ago—asserted that there is in the hand “a universal plan extending through all animated nature and which has prevailed in the earliest condition of the world, and that on the most comprehensive study of those subjects, we everywhere behold prospective design” (1).
In the second half of the 20th century, the writings of John R. Napier, an anthropologist-physician, are preeminent. His book Hands, first published in 1980 and now in its third edition, is the book to be recommended to nonspecialists interested in the evolutionary, functional, and behavioral aspects of the hand.
The best comparison and differentiation between nonhuman primates' hands and our own lies in the manner in which the hand is able to grasp something. The anthropoids' grip is strong and secure, but its range of function will remain small because of its less developed thumb. It is at best a “power grip,” but it does not have the “precision grip” of the human hand, which has achieved excellent refinement in prehensility.
This, however, does not mean that the human hand has lost the more primitive ability of the power grip or any other movement of the primate foot-hand. Essentially, the anatomical structure of our hand is no different from that in a gorilla, with the exception of the opposability of the thumb. What has changed is that over time, a strong hand remained strong but acquired more intricate capabilities. Monkeys are basically quadrupedal; man is fully bipedal. Our upright walk makes all the difference. During the last century, many discoveries have led to the understanding of the origins of our hands and their capabilities.

ORIGINS

In 1650, Archbishop James Ussher determined to his satisfaction that the earth was created on the evening of October 22, 4004 BC. John Lightfoot, another divine, claimed that the correct time was 9:00am on October 26, 4004 bc. We now know they were off by many millions of years.
Precursors of the skeleton of our human hand can be traced back at least 370 million years to the pectoral fin of an extinct fish. The basic pentadactyl (5-digit) hand is found in skeletons of mammal-like reptiles that lived 200 million years ago. Sixtyfive million years ago, the basic hand skeleton became a fixed mammalian characteristic. Around 25 million years ago, the apes living in the forests began to develop more mobile forelimbs and hands with longer, stronger fingers. Their thumb was short and lacked both long flexor and extensor tendons, and the fingers and nails were curved to aid in grasping tree limbs. Our first unequivocal ape ancestor lived 19 million years ago. Named Proconsulitous, it was about the size of a fox terrier and had fingers that were flat nailed and had a pseudo opposable thumb. Some apes developed a knuckle-walking gait similar to that of modern chimpanzees.
About 5 million years ago, future man split off from the apes, and between 3 and 4 million years ago “Lucy” developed. Properly named Australopithecus afarensis, her given name was derived from the Beatles' song “Lucy in the Sky with Diamonds,” which was popular at the time her bones were discovered (2). Lucy was 31/2' tall with arms longer than modern man and small, strong hands. Thus, around 3 million years ago we have the first evidence of a true bipedal hominid. It was another million years before tool use developed. There is now evidence that modern man has existed for at least 100,000 years and that he used tools made of stone, bone, horn, and wood. The science of molecular genetics has now vindicated Darwinism and, no doubt to the discomfort of some, has shown that almost 99% of our DNA is identical to that of the chimpanzee.

STRUCTURE AND FUNCTION

Skin is the most ancient sense organ of our body, and the skin of our hand is highly specialized to provide detailed sensory feedback. Since mobility is concentrated toward the concavity of the palm, its nerve endings are far more numerous than are those on the dorsum. The most sensitive area is the central whorl or loop of the fingertips in which the threshold of touch is 2 g per mm2. In contrast, the threshold is 33 g in the forearm and 26 g in the abdomen. This acute sensibility is explained by the presence of some 2400 to 2500 nerve endings in each 9-mm2 area. Deeper sensibility in the fingers is supplied by a rich nerve plexus in which, among many nerve endings, are >800 of the estimated 2000 Pacinian corpuscles in the whole body.
On the dorsal extensor surface the skin of our hand is thin and loose, and on the palmar aspect it is thicker and tethered to the deep fascia by strands passing from the flexion creases. The palmar creases or “skin joints” do not correspond to the underlying bony joints but anchor the skin during grasp. Subsidiary creases on the fingers fold up the skin that balloons up when the fingers are flexed (see your own proximal interphalangeal joint).
These creases are not the result of use; they are present in the newborn baby's hands. Many other minor creases are present, and throughout the palmar aspect papillary ridges carry sweat glands which open along the ridge crests. The sweat provides an adhesive quality, preventing slippage of tools, and enhances the appreciation of pain and touch. The pattern of these ridges is unique and unchanging and is established by the 12th week of intrauterine life.
John Napier has written, “I suppose we all have our heroes. I have three—Hunter, Bell, and Darwin. John Hunter turned our attention from the structure of the hand to its function; Bell related the function of the hand to the environment; and Darwin demonstrated that the environment, by the process of natural selection, gave birth to structure” (3).
I would add a fourth hero, a general practitioner from Boulogne, France, Gulliaume Duchenne, who in his book Physiology of Motion published in 1855 made the forthright statement, “The hand as understood physiologically is nothing but an unsightly paw more awkward than useful.” Despite this stricture, he comprehensively described the normal and abnormal motions of the hand. His great contribution was to use electrical stimulation to demonstrate the complexity of motion during grasp, pointing out that many muscles participate, some as direct motors, some as moderators, some as restrainers, and some as antagonists.

THE MUSCLES

Mechanically, the grasping hand is a 2-sided chuck with the mobile thumb on 1 side and the fingers on the other. This chuck provides our refined and powerful pinch and grasp mechanism. The fingers on the opposite side of the grasping chuck are each capable of independent action. Opposing the powerful flexor mechanism is the weak extensor apparatus, whose major function is to open the fist and lift the digits against gravity.
The power of grasp is derived from 2 groups of muscles: the extrinsic and the intrinsic. The extrinsic muscles in the forearm provide the major power of the hand. The intrinsic muscles within the hand are of fundamental importance, since they are largely responsible for the refinement and delicate control of digital movements. These small muscles achieve their control by modifying and moderating the actions of the long extrinsic muscles.
Opening the hand and then closing it around an object is a very complicated motion. Simultaneous contraction to varying degrees of the 35 muscles in the forearm and hand will create a grasping motion. If you are among the 20% of humans who do not have a palmaris longus muscle, then you have only 34 muscles working for you. Unfortunately, you lack a muscle that can be used in reconstructive surgery. Its absence does not hinder you. To test if you own one, press your thumb tip against your little fingertip and flex your wrist against resistance. The palmaris tendon will stand out under the skin in the middle of the wrist crease.
Three phases operate when grasping large objects. In the first the hand opens widely from action of both the long extensors and the intrinsics. Then the object is surrounded largely by intrinsic action. Closure and firm grasp result from the strong action of the extrinsic flexors and the intrinsics of both the thumb and fingers. Finally, slight extension of the wrist tightens the grip even more.
The great variability in the postures of grasp would seem to exclude easy classification. But in 1956 Napier in his classic paper “The prehensile movements of the human hand” showed that all forms of grasp can be grouped as either power or precision grasp, with a third category combining elements of both (Figure ​(Figure11) (4).
Figure 1
Power grasp and precision grip. In grasp the object is pulled into the hand and rests on the thenar muscles. In precise actions the object is usually held away from the palm. Reprinted with permission from Napier JR. The prehensile movements of the human ...
Power grip is thought to have developed early in humans and consists of a prehensile movement in which the object is grasped by the fingers and pressed against the buttress of the thumb and its intrinsic muscles. This is a powerful movement with little skill involved. Precision grip is thought to be the most recent adaptation of the evolving human hand. It is an accurate prehensile action in which the object may be held away from the palm between thumb and fingertips. Some activities require features of both grips, as in tying 2 pieces of string together; the power fingers (ring and small) hold the string, and the precision digits (thumb, index, and long) do the precise activity of creating the knot. The so-called hook grip, while of great use to the apes suspended in trees, is only of use in humans when carrying suitcases.
Formerly 3 clinical models could be used for the study of grasp. Nowadays, with the conquest of poliomyelitis, only the rheumatoid hand and the leprosy hand are available. Practically every biomechanical imbalance that afflicts the hand occurs in one or the other of these 2 diseases.
Studies show that a power grasp of about 5 lbs per in2 will keep a hammer handle from slipping out of the palm. However, if skin sensory feedback is impaired, then strength has to be increased to provide deeper sensory feedback. In the extreme case of the “blind” hand of Hansen's disease (leprosy), the neurological changes cause a collapsed posture of grasp and a concentration of force at the tips of the digits. The normal palmar surface grip area in an adult is about 10 in2. The intrinsic minus posture of leprosy allows only fingertip grip, concentrating the force of grip into an area of about 1 in2 (Figure ​(Figure22).The final resultant force in this small area is huge and reaches about 250 lbs per in2:
Figure 2
Intrinsic minus hand. The metacarpophalangeal joints are hyperextended, and the interphalangeal joints are flexed. Note that the tip of the long finger is shortened and rounded; absorption of the terminal phalanx has already started.
5 lbs per in2×5×10 in2=250 lbs per in2
normal pressureincrease for lack of sensibilityadjustment in surface area*actual pressure during grasp
*Pressure usually applied in an area of 10 in2 is now in an area of 1 in2.
The high grip pressure causes persistent microfractures, bone absorption, and ultimately disappearance of the digits (Figure ​(Figure33).
Figure 3
Hansen's disease. (a) Late stage. The fingers have absorbed and only a flipper of a hand is left. (b) X-ray of late stage.
Just as in leprosy, in which the internal forces of grasp destroy the skeleton, so in rheumatoid disease the aberrant forces produced by soft tissue disease disarray the normal forces of grasp. The more the patient increases the force of grasp, the greater the self-destruction of the normal postures of grasp.
Many factors influence the strength of grasp. Studies show that grip strength is greatest around 3:00 PM each day (5). Actual strength will vary with age and sex. A strong grasp reflex is present at birth. A baby begins to develop control of strength around the age of 2 as appreciation of the friction between skin and object develops. Progress is slow and early on is compensated for by excessive use of force (6). Gloves produce a significant drop in grip strength. Ordinary working gloves cause a reduction of 14% to 28%, while the inflated gloves of the astronaut produce a 37% reduction in strength.
Proper grasp is dependent upon appropriate lengths of the constituent bones of the palm and digits. These lengths are in fact proportionally related and determine the form and shape of grasp. The different lengths of the fingers disappear when a sphere is grasped; the fingers abduct and rotate and the tips line up. When grasping a cylinder, there is a normal inclination of palmar grasp, a fact unfortunately not well known to the manufacturers of crutches, who still copy the ancient Roman model. If only they would slope the handle, it would not force the wrist into a painful end position(Figure ​(Figure44).
Figure 4
The inclination of grasp. (a) Horizontal crutch handles force the wrist into an uncomfortable position. (b) With a sloped handle, the wrist is comfortably in line with the forearm. Reproduced with permission from Geriatrics 1960;15:733–745. Copyright ...
Our work has shown that regardless of wrist position, the percentage of total grasp force allocated to each finger is constant. The long finger shows the greatest amount of force, with approximately 33% of the total force. The index and ring fingers have about 25% each, and the small finger has approximately 16% of the total force (7).
The type of grip used in any given activity is a function of purposeful action and is not dependent on the shape or size of the object grasped. Humans have now moved beyond using rocks and fallen branches as tools, and as Benjamin Franklin said, “The tool user has become a tool maker.” Unfortunately, the current— cosmetically attractive—tendency to make digital profiles on tool handles severely restricts the range of hand sizes that can comfortably grasp the tool. The size and shape of tool handles should be such that the digital joints are near mid-flexion so that tool retention is high and the muscles are only partially stretched. Recent “ergonomic” designs show a great improvement. In surgery a round handle for the scalpel blade is wonderful; one can readily adjust the blade angle. The regular thin flat handle was probably invented by the Romans!

RESTORATION

In the latter part of World War II the American army set up 10 hospitals in the USA for the exclusive treatment of upperlimb injuries. Thirty-five young surgeons were trained in reconstructive hand surgery, and what is now a worldwide specialty was born.
The basic objective of the specialty is the restoration of skilled function to a hand disabled by congenital defects, trauma, or disease. The fundamental functions are that of precision grip or power grasp. Two factors are paramount in their restoration: a thumb that moves or can be stabilized and fingers that flex. In massive injury, particularly when it is bilateral, restoration of both power and precision grips to both hands may not be possible. It may well be that the remaining serviceable parts will restore precision grip to the nondominant hand and power grip to the remnants of the dominant side. This is far better than attempting to restore both functions to both hands using inadequate resources.
Destruction of the individual nerve supply within the forearm or hand, such as the median, ulna, or radial nerves, produces recognizable patterns of function loss. Standard plans of effective tendon transfers have evolved, and such surgery has now become routine. When >1 nerve is involved, functional restoration becomes more difficult and the results are less efficient. Precision activities are lost first and, depending on the extent of damage, only grossly controlled motions may be possible.
During the days of poliomyelitis, paralysis of thumb opposition was a frequent occurrence. Since this is a fundamental component of grasp, a great many operations have been suggested for its restoration. Unfortunately, many of these procedures failed to appreciate that the thumb is, in effect, a post projecting into space with a very mobile joint at its base. Accordingly, a thumb has to be supplied with at least 3 “guy ropes” distributed around its circumference to hold the thumb erect. The flexor pollicis longus, the extensor pollicis longus, and the abductor pollicis longus usually supply the necessary stability. Once stability is achieved, then a fourth muscle can be transferred to move the thumb into opposition.
The prime mover into opposition is usually made from the flexor superficialis of the ring finger. Its removal does not interfere with grip in the presence of an intact flexor profundus tendon. A pulley is made in the region of the pisiform bone, and the transfer is attached near the metacarpophalangeal joint. After 3 weeks of immobilization, the transfer can be taught to produce opposition in an astonishingly short time—usually about 10 minutes.
Since the conquest of poliomyelitis, this operation is still in use to provide opposition when its absence is caused by trauma or neurological disease. For patients with progressive neurological conditions, a positive “can-do” attitude will provide, through an operation lasting an hour to an hour and a half, significant temporary improvement in grasp. Some of these individuals have been among my most grateful patients, even though they know the result cannot be permanent.
When trauma has amputated the thumb or one is born with an absent thumb, the hand is reduced to a virtual hook and no form of opposition is possible. Indeed, Napier has written, “Without the thumb the hand is put back 60 million years in evolutionary terms to the stage when the thumb had no independent movement and was just another digit” (8). Such a state is unacceptable, and a thumb has to be provided. The best substitution is one of the fingers, and technically it is possible to move any of the fingers across onto the base of the destroyed thumb. However, the use of any finger other than the index produces an indifferent thumb and is best regarded as a surgical triumph and a functional disaster.
The translation of an index finger onto a thumb stump is a relatively easy procedure and gives a highly functional result (Figure ​(Figure55). The cerebral cortex readily adjusts to its new responsibilities, but at first the new thumb is often inadvertently used by its owner as a pointer. This patient's insurance company kept writing to me demanding to know whether he should be compensated for loss of thumb or loss of index finger. My reply? Both!
Figure 5
An electrical accident burned off both thumbs in this adult man. Parts a, b, and c show 3 different views of the transposition of both index fingers, which restored grasp. The man returned to work on power lines.
In infants born with 4 fingers but no thumb, a thumb can be readily made from the index finger. However, the conversion of an index finger to a thumb necessitates some shortening since in the normal hand the tip of the thumb usually reaches just proximal to the line of the proximal interphalangeal joint of the index finger. This shortening is accomplished by removal of most of the metacarpal shaft, but the head is retained since it will become a new trapezium (Figure ​(Figure66). The key to this shortening is destruction of the growth plate of the metacarpal head. This arrests longitudinal growth at the base of the new thumb and prevents the development of the grotesque thumbs made by earlier methods (Figure​(Figure77). This operation should be done early so that the child uses the thumb normally and is never aware of its original absence. I usually do it at about 6 months of age and believe it should always be done before the first birthday.
Figure 6
Pollicization—joint distribution. The 3 joints of the index finger become the 3 joints of the thumb, but the index metacarpophalangeal (MP) joint becomes the carpometacarpal (CMC) joint of the thumb. Reprinted with permission from Flatt AE.The ...
Figure 7
Pollicization. In the early development of this operation, the growth center in the index metacarpal head was not destroyed. It continued to grow, producing a grotesque digit. Reprinted with permission from Buck-Gramcko D. Pollicization of the index figure. ...
Infants born with webbed hands in which their thumb is tightly adducted to the index finger can have full restoration of grasp by liberation of their thumb. Three rotation flaps can be moved down the forearm to completely cover the thumb with sensate skin, and no skin grafting is necessary (Figure ​(Figure88).
Figure 8
(a) Adducted thumb. (b, c) By judicious use of rotating skin flaps, the thumb can be liberated and clothed with full-thickness skin. Vascular supply and cutaneous nerves are carried in the flaps. Reprinted with permission from Flatt AE, Wood VE. Multiple ...
Even patients with high spinal cord lesions, which leave only 1 forearm muscle under voluntary control, can be given significant improvement of function. For the patient illustrated in Figure ​Figure99 a 2-stage operation was used. The first procedure anchored the finger flexor tendons to the radius with the lengths arranged so that there was a normal cadence of flexion with the least in the index and the most in the small finger. When the wrist was extended by the sole working muscle (extensor carpi radialis longus), the fingers would close in grasp. However, the paralyzed thumb intruded into the palm, blocking grasp. The second-stage operation shortened the thumb by removing the proximal phalanx and fusing the distal phalanx to the metacarpal head. The phalanx was used as a bone graft, fixing the thumb in abduction and radial deviation from the hand. This provided a variety of useful functions for a previously flaccid hand. I first published this operation in 1964 and have used it ever since for patients with high neurological loss and for spastic patients. Surprisingly, these hands do not appear grotesque, and most lay people do not realize the thumb has been shortened.
Figure 9
Quadriplegia. The ability of limited grasp can be restored with only 1 functioning muscle in the forearm. (a) The thumb is shortened and stabilized. (b) A variety of functions are supplied by the operation. Reprinted with permission from Flatt AE. Indications ...
The field of hand surgery has grown exponentially since World War II. The original 35 military hand surgeons founded the American Society for Surgery of the Hand in Chicago on January 20, 1946. Today there are 1213 active members of this society dedicated to the improvement of and education in restoration of functions to the hand. A major effort has been the training for the next generation of surgeons; I have trained 50 hand surgeons from 11 different countries and many of my colleagues have similar records, so that now 49 countries have trained hand surgeons who are members of the International Federation of Hand Surgery.

References

1. Bell C. The Hand, Its Mechanism and Vital Endowments as Evincing Design. London: William Pickering; 1834.
2. Johanson DC, Edey MA. Lucy. New York: Warner Books; 1982. p. 18.
3. Napier JR, Tuttle RH. Hands. Princeton: Princeton University Press; 1993. p. 9.
4. Napier JR. The prehensile movements of the human hand. J Bone Joint Surg. 1956;(38B):902–913.
5. Business Week October 2, 1995.
6. Wilson FR. The Hand. New York: Pantheon Books; 1998. p. 121.
7. Hazelton FT, Study of the Influence of Wrist Position on the Force Produced by the Finger Flexors[master's thesis]. Iowa City: University of Iowa, 1972.
8. Napier JR. Hands: 55.
Articles from Proceedings (Baylor University. Medical Center) are provided here courtesy of Baylor Health Care System
Posted by at No comments:

Congenital clasped thumb


J Child Orthop. 2007 November; 1(5): 313–322.
Published online 2007 October 17. doi:  10.1007/s11832-007-0057-x
PMCID: PMC2656739

Characteristics of patients with congenital clasped thumb: a prospective study of 40 patients with the results of treatment

Hisham Abdel Ghani,corresponding author1 Ahmed El-Naggar,1 Mohamad Hegazy,1 Atef Hanna,1 Yehia Tarraf,1 and Samia Temtamy2
Author information ► Article notes ► Copyright and License information ►

Abstract

Purpose

Congenital clasped thumb is a deformity that is associated with heterogeneous congenital anomalies and it has been addressed in many congenital syndromes. The aim of this study was to diagnose and evaluate cases of clasped thumb as regards the associated congenital anomalies and syndromes, and evaluation of the results of treatment of such cases.

Methods

A prospective study on 40 patients with 73 clasped 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 and radiological examination and genetic assessment. The cases were classified using the Tsuyuguchi et al. (J Hand Surg [Am] 10:613–618, ) classification into three types. Conservative treatment was adopted in ten hands, and surgical treatment was performed for 28 hands in 17 patients, with an average follow-up of 26 months.

Results

Positive consanguinity was recorded in 57.5% of cases. Associated anomalies were recorded in 77.5% of cases. Type I was the most common one, followed by type III and then type II. Conservative treatment is effective in type I cases when presented early, and all patients were satisfied with the results of surgical treatment.

Conclusions

We reported associated anomalies which are to our knowledge have not mentioned before in the literature which include; congenital blindness, radial deviation of the index finger and ventricular septal defect. We found that 68% of the patients had associated syndromes, and this has not been mentioned before. In this study, we found that there were no difference between type II and type III clasped thumb as regards the pathological findings, severity, the operative procedures, the treatment protocol and the operative results. Properly planned treatment gives satisfactory results.
Keywords: Thumb, Clasped thumb, Thumb contracture, Flexed adducted thumb

Introduction

A persistent flexed adducted thumb after the 3rd or 4th month of life is called congenital clasped thumb []. It is due to deficiency of the extensor pollicis brevis or longus or both. The deformity is usually accompanied with a variable degree of narrowing and contracture of the first web space []. This deformity is usually associated with other generalized musculo-skeletal malformations, commonly; arthrogryposis, digitotalar dysmorphism and Freeman–Sheldon syndrome.
Most of the literature has discussed a surgical technique or case reports of associated anomalies or syndromes. Little has been written about the epidemiology of the deformity.
The aim of this study is to characterize a group of patients describing the associated anomalies and syndromes, the possible predisposing factors and results of treatment.

Patients and methods

Forty patients with 73 congenital clasped thumbs were prospectively studied. There were 29 males and 11 females, with an average age at presentation of 27 months (range from 3 months to 11.5 years). The condition was bilateral in 33 cases.
The patients were exposed to thorough assessment, including recording of the family history, pregnancy history and full clinical assessment performed by a paediatrician. Genetic assessment was intended to be done for all cases by a paediatric geneticist (last author). Radiographic examinations of the extremities, skull, spine, and the pelvis and abdominal ultrasonography were conducted for all the patients. Echocardiography was done when recommended by the paediatrician.
The deformed thumbs were classified according to Tsuyuguchi et al. [] into three types (Fig. 1).
Fig. 1
a Type I: supple clasped thumb. The thumb could be passively abducted and extended against the resistance of thumb flexors, without other digital anomalies. b Type II: clasped thumb with hand contractures. The thumb could not be passively extended and...
Thirty-eight hands were treated. Non-operative treatment was followed in ten hands in five patients who presented before the age of 1 year (eight hands type I and two hands type II). Surgical treatment was done in 28 hands in 17 patients (cases presented later than 1 year of age or which had not responded to non-operative treatment) (Tables 1, ​,22).
Table 1
The distribution of the operated patients with regard to sex and bilaterality
Table 2
The number of different types of clasped thumb operated upon
The cases which were not treated were; nine hands waiting for surgery, 16 hands where the patients did not return for surgery, and ten hands where the parents refused surgery.

Treatment protocol

  • Non-operative treatment: full time splinting of the thumb in extension for at least 6 months, followed by night splinting for further 6 months after achieving active extension of the thumb.
  • Operative treatment: surgical procedures for every case were variable according to the degree of narrowing of the first web, stability of the metacarpophalangeal (MP) joint and muscle deficiency.
Surgery aims at widening the narrow first web space, including the skin and deep tight structures. Skin widening was done through either simple Z-plasty, four-flap Z-plasty [], butterfly flap [], dorsal rotational advancement flap [] and modified dorsal rotational advancement flap []. The choice of the technique is variable according to the degree of narrowing. Through the skin incision designed to widen the web, the dissection is deepened through underlying fascia over the intrinsic muscles, protecting the distal arborisation of the superficial radial nerve, the flexor tendon and neurovascular bundles to the index finger. The tight structures are identified to be released; the origin of adductor pollicis muscle is released from the third metacarpus. If necessary, the first dorsal interosseous muscle is elevated from the first metacarpus. The thumb is then manipulated into extension and abduction. If necessary, the carpometacarpal joint capsule is released. After achieving full release, the first metacarpus is maintained in full abduction with two crossed k-wires across the first web space.
A markedly unstable MP joint necessitated chondrodesis, but in cases of mild laxity of the ulnar collateral ligament, double breasting of the capsule was done. In either case, the MP joint was transfixed with a single or two crossed k-wires.
Tendon transfer was done to restore active extension of the MP joint when it was stable or after achieving stability with reconstruction of the ulnar collateral ligament. The extensor indicis was the preferred tendon for transfer, and if it was absent, one slip of the flexor digitorum superficialis muscle is transferred to the vestigial remnant of the deficient thumb extensors (Table 3).
Table 3
The different surgical procedures done
An above-elbow splint was applied immediately. The k-wires were removed after 6 weeks of surgery. The position was maintained in a night splint with the thumb extended for at least 6 months post-operatively, with daytime active use of the thumb being encouraged. The average duration of follow-up was 26 months (range from 16 to 60 months).
The criteria used to assess results of treatment were:
  • I: Parents’ satisfaction: regarding cosmetic appearance and function.
  • II: Thumb position and appearance: degree of abduction and rotation.
  • III: Stability of MP joint.
  • IV: Thumb function: degree of opposition and the ability to grasp different objects.
The degree of abduction, rotation, stability and opposition were graded into four grades according to Gilbert (personal communication) (Table 4).
Table 4
Gilbert’s method of assessment of thumb function (personal communication)

Results

The results will be discussed under the following headings:
  • I: Clinical findings
  • II: Operative findings
  • III: Results of treatment

Clinical findings

Family history

Twenty-three patients had positive consanguinity. First-degree consanguinity was found in 13 patients and far relationship in ten patients. Parents’ anomalies were found in six patients; the most common parents’ anomalies were club feet (two patients) and windblown deformity of the hands (two patients).
Seven patients had either the brother or the sister affected with other congenital anomalies. One patient had a sister with clasped thumb, and another one had three brothers who had other congenital anomalies but they could not be assessed. One patient had the mother, the aunt and the grandfather with windblown deformity, and his cousin had clasped thumb.

Prenatal history

Positive history of fever during pregnancy was reported in seven patients, but the mothers could not specify the type of infections they had had. One patient had a history of radiation exposure during pregnancy. Drug intake during the first trimester was found in 12 patients. Most of the mothers could not specify the types of medication they received (Table 5).
Table 5
Types of drugs taken during the first trimester of pregnancy in 12 patients

General examination

The distribution of different types of clasped thumb and their sex distribution are mentioned in Table 6. Thirty-one patients (58 hands) were found to have associated anomalies.
Table 6
The different types of clasped thumb with sex distribution
Facial abnormalities were found in 18 patients; ptosis, antimongoloid obliquity of the palpebral fissure, cleft palate, broad bossed forehead, flat face, depressed nasal bridge and long philtrum. Whistling face was diagnosed in six patients. Two patients had congenital blindness. Four patients had short neck, and one had additional webbing. Congenital heart anomalies were found in two patients; one had atrial septal defect and the other had ventricular septal defect. Scoliosis was found in one patient with arthrogryposis, but MRI was not done. No abdominal anomalies were found in any patient, but accidentally discovered renal stones were found in two patients (Tables 7, ​,8,8, ​,99).
Table 7
Lower limb anomalies associated with clasped thumb
Table 8
Upper limb anomalies associated with clasped thumb
Table 9
Associated hand anomalies

Associated syndromes

In 11 patients, genetic assessment was refused by the parents, and their associated syndromes were not diagnosed; two of them had congenital blindness with clasped thumb. Different syndromes were present in 20 patients out of the 29 patients assessed (68%) (Table 10).
Table 10
Associated syndromes

Patterns of inheritance among genetically assessed cases

Autosomal dominant inheritance: there was variable expressivity of the autosomal dominant inheritance in one parent and sibs of 13 patients. These patients had isolated Freeman–Sheldon syndrome (four patients), clasped thumb deformity (three patients), arthrogryposis multiplex congenita (two patients), clasped thumb club foot syndrome (two patients), congenital contracture arachnodactyly (one patient) and digitotalar dysmorphism (one patient).
Suspected autosomal recessive inheritance: 13 patients had positive family history of consanguinity without a family history of similar conditions. These patients have isolated clasped thumb deformity (six patients), arthrogryposis multiplex congenita (three patients), multiple pterygium syndrome (three patients), and Emery–Nelson syndrome (one patient).
Sporadic hands: three patients had no consanguinity or similar familial anomaly; two of them have Freeman–Sheldon syndrome, and the other have digitotalar dysmorphism.

Operative findings

Abnormal pathological anatomy

Attenuated extensor pollicis longus and brevis were found in all hands, and they appeared as vestigial strands of tendon-like structures measuring about a millimeter in diameter. Absent extensor indicis was detected in one out of eight hands with tendon transfer.
Contracture of adductor pollicis muscle was found in 13 hands (seven hands had Type III and six hands had Type II clasped thumb). Meanwhile, first dorsal interosseous muscle was contracted in nine hands (six hands had Type III and three hands had Type II clasped thumb).
Global instability of the MP joint was present in 18 hands. Laxity of ulnar collateral ligament of the MP joint was detected in two hands (Type III clasped thumb). The true nature of instability was identified after release of the web space.
Abnormal articular surface of the first MP joint was detected in six hands (four hands had Type II and two hands had Type III clasped thumb) with hypoplasia of the volar aspect of the first metacarpal head. The dorsal capsule of the MP joint was adherent to the cartilage of the metacarpal head and sharp dissection was needed to separate it in eight hands (four hands Type II and four hands Type III clasped thumb). Flexion contracture of the MP joint was present in eight hands (four hands Type II and four hands Type III).

Post operative complications

Superficial necrosis of the tip of the modified dorsal rotational advancement flap with venous congestion occurred in one hand Type II, and it was treated with repeated dressings without effect on the result. Proximal retraction of the tip of the dorsal rotational advancement flap was noticed in all cases. This produced some re-narrowing of the web, which was avoided in later cases by using the modification of this flap []. Non-union of chondrodesis of MP joint occurred in two hands (Figs. 2, ​,33).
Fig. 2
Ulnar drift hand
Fig. 3
Radial deviation of the index finger associated with flexion deformity of the lateral four fingers

Results of treatment

Results of operative treatment

Twenty-eight hands were assessed postoperatively with regard to:
(1) Parent’s satisfaction. The parents of all the patients were satisfied with the results (Fig. 4).
Fig. 4
a Severe type III clasped thumb in patient with arthrogryposis treated surgically with release of the first web, widening the web with modified dorsal rotational advancement flap and chondrodesis of the MP joint of the thumb. b Result of surgical treatment ...
(2) Cosmetic appearance. The simple Z-plasty deepened the web, transforming it into a slit, and did not give the normal rounded appearance of the web. The appearance of the first web space was better with the other techniques. The modified dorsal rotational advancement flap allowed maximal degree of widening more than the other techniques used. Twenty-four thumbs had excellent abduction, and four thumbs had good abduction. Twenty-six thumbs had excellent rotation, and two had good rotation.
(3) Stability of the MP joint. The stability of the MP joint of the thumbs operated upon was excellent in 24 cases. In the two hands with non-union of the chondrodesis, revision of chondrodesis was needed in one thumb with poor stability, while in the other the stability was fair and there was no need for surgery; otherwise, the rest of cases with chondrodesis had excellent stability (Fig. 4). The stability of two cases with ligamentous reconstruction of the ulnar collateral ligament was graded as good.
(4) Thumb functions. Active extension of the thumb was full in all cases for which tendon transfer was done (Fig. 5).
Fig. 5
a Type I clasped thumb. b Result of surgical treatment after transfer of extensor indicis to remnant of the extensor tendons
Ten thumbs had excellent opposition, 14 thumbs had good opposition and two thumbs had fair opposition. Two thumbs were unable to oppose, and opponensplasty was needed. In all the hands for which muscle transfer to the extensors of the thumb was done, the opposition were excellent. There was improvement of the grasp pattern in all the operated thumbs. Twenty-five hands were able to pick up a pen and a key and were able to grasp a ball. Two hands (one patient) wer able to pick up a key and a pen between the thumb and the middle finger because of the severe flexion deformity of the index finger. In one hand, the ability to grasp and pick up an object could not be assessed.

Results of non-operative treatment

Non-operative treatment was successful in eight hands type I, with achievement of full active extension of all joints of the thumb. There was no improvement in the two hands of type II that will need surgical treatment.

Discussion

Congenital clasped thumb is a deformity that is associated with heterogeneous congenital anomalies and syndromes []. The incidence of these anomalies and syndromes vary, and are based on study of small groups of patients. Little has been written about the distribution and epidemiology of clasped thumb. Also, the characteristics of the patients with clasped thumb are not well described in the literature.
The clinical evaluation of the patients in this study revealed that the male-to-female ratio is 2.5:1, which is similar to the reported ratio by Lin et al. [], and is near to the estimated ratio reported by Flatt []. However, it differs from the 1:1 ratio reported by Tsuyuguchi et al. []. This difference can be attributed to the wide variety of syndromes associated with clasped thumb and their different modes of inheritance, and also the small number of reports in the literature that document the sex ratio of the affected cases.
With regard to the possible predisposing factors, the incidence of positive consanguinity is 60% and positive family history in our study is 32.5%, which is much higher than the 10% positive family history that was reported by Tsuyuguchi et al. [], who also did not mention the incidence of consanguinity.
The high percentage of positive consanguinity and family history in about one-third of our cases, and the high incidence of bilateral cases, strongly suggest that the genetic defect is an important causative factor []. However, there may be an underestimation of the percentage of drug intake. We noticed that mothers might deny intake of drugs taken to abort babies. Also, the drug may be in the form of a herbal extract, which may be taken for the same purpose. In the majority of cases, other therapeutics were taken without knowing the existence of pregnancy.
One-third of cases were sporadic. This agrees with the literature regarding the causative factors for such an anomaly []. However, the exact causative factors are not yet known.
This study confirms the previously reported high incidence of associated congenital anomalies with clasped thumb [, , –]. About 77.5% of our patients were found to have associated anomalies; this value differs according to the number of syndromes included in the literature, and no previous literature studied the incidence of congenital anomalies with clasped thumb, as the different syndromes were studied separately or the literature contains case reports of certain syndromes. The incidence of upper limb anomalies in our patients (15%) agrees with reported cases of Temtamy and McKusick [].
Other anomalies encountered included congenital heart disease in the form of ventricular septal defect—which was detected in one patient who had no other anomalies except unilateral type I clasped thumb—and this association was not found to be reported in the literature. We reported other anomalies, which to our knowledge have not been mentioned before which include two patients with congenital blindness in association with bilateral clasped thumb, and a case with radial deviation and rotation of the index finger. No abdominal anomalies were encountered in this study, and this agrees with the literature [, ,].
Associated syndromes were encountered in 68% of patients, and this percentage was not studied before in the literature.
We used the classification suggested by Tsuyuguchi et al. []. This classification was also used by Mih []. We found that there was no difference between type II and type III clasped thumb with regard to the pathological findings, severity, the operative procedures, the treatment protocol and the operative results; thus, it was wiser to classify the clasped thumb into supple and complex types, as McCarroll [] did.
The distribution of different types of clasped thumb and the male to female distribution was almost the same as reported by Tsuyuguchi et al. [] (Table 11).
Table 11
Comparison between the distributions of different types of clasped thumb in the present study and the study presented by Tsuyuguchi et al. []
Our protocol of management is similar to that followed by Weckesser et al. [], Lipskeir and Weizenbluth [] and McCarroll [], who divided the clasped thumb into two types (supple and complex), and treated the supple type with splinting and tendon transfer if splinting failed, while the complex type was treated by correction of the fixed contractures and reconstruction of lax ligaments and tight skin as appropriate. Tsuyuguchi et al. [] cases were treated by splinting for types I and II cases and operative treatment for type III and type II cases which didn’t respond to conservative management.
In this study, 50% of operated cases were type III clasped thumb; 29% of cases were type II, and only 21% were type I cases who were presented at an age older than 1 year. This differs from the cases presented by Tsuyuguchi et al. [], where 50% of the patients were type I and 50% were type II; this can be explained by the young age at presentation of their type I cases, as all their patients were within their first 7 months of life.
The operative findings agreed with Crawford et al. [] and McCarroll [], in that the extensor tendons were not absent but attenuated in the three types. Our findings also agreed with McCarroll [], in that the complex type of clasped thumb (types II and III) have contractures in the soft tissues in the volar surface of the digit, involving all tissues including skin, subcutaneous fascia, periarticular structures and in the radial collateral ligament–volar plate complex of the MP joint. The dorsal capsule of the MP joint is adherent to the cartilage of the metacarpal head, and there is abnormality of the articular surface of the metacarpal head in some cases of types II and III clasped thumb. The shortening of the flexor pollicis longus muscle was present in cases of types II and III, but Z-lengthening was needed in few cases because in the majority of cases we did chondrodesis of the MP joint.
We noted that the severity of these pathological findings is variable, and dependent on the age of the patient at the time of surgery. We also noted that these findings were present in types II and III clasped thumbs, and there was no difference in these pathological findings in both types.
We used different skin incisions in this study to widen the web space. No technique can be standardized for release of the web as this depends on the severity of web narrowing and degree of contracture; as a result, it is difficult to compare the different methods used for release.
There were no universal criteria for the evaluation of the results of management of clasped thumb, due to the difficulty in assessing the thumb function at that young age, and other authors used different systems for evaluation of their results. Some authors used the degree of active extension of first MP joint as the reference for evaluation [, ]. Tsuyuguchi et al. [] added the degree of active radial abduction of the trapeziometacarpal joint to their system of evaluation. Lipskeir and Weizenbluth [] added the width of the first web space to their scoring system, and they mentioned that active extension of first MP joint is the most important factor for the apprehension of large objects.
We used a combination of criteria to evaluate the thumb function, because it is of no benefit to achieve active thumb extension without achieving stability of the MP joint or without widening of the web. It is very important to consider the stability of the MP joint. Using the active extension as the sole criteria for assessment is possible in type I cases where this is the only deficient function.
The results of splinting in this study were excellent in type I clasped thumb [, ]. The small number of patients that followed the non-operative treatment in this study is attributed to the delayed presentation of the patients until after the age of 1 year.
In this study, the results of tendon transfers done for type I clasped thumb were excellent. We did not use an osseous tunnel in the proximal phalanx for the extensor indicis tendon as originally described [], and instead we sutured it to the attenuated extensor tendon of extensor pollicis brevis, as described by Mih [].
In the case of ulnar collateral ligament instability of the MP joint, ligamentous stabilization is a prerequisite for tendon transfer. Although the ligament reconstruction did not give excellent stability, the residual instability did not interfere with thumb function. In the case of global instability of the MP joint, chondrodesis is the best way to achieve stability, and at the same time it obviates the need for tendon transfer. The results of chondrodesis are better than that reported by Tsuyuguchi et al. [] and Lipskeir and Weizenbluth [].
In this study, we found that properly planned treatment according to the type of the deformity improves the cosmetic appearance and functional capabilities of the hand.

References

1. Temtamy S, McKusick V (1978) The genetics of hand malformation. Alan R. Liss, New York .
2. Crawford H, Horton C, Adamson J (1966) Congenital aplasia or hypoplasia of thumb and fingers extensor tendons. J Bone Joint Surg Am 48:82–91 .
3. Tsuyuguchi Y, Masda K, Kawabata H, Kawai H, Keiro Ono (1985) Congenital clasped thumb: a review of forty-three cases. J Hand Surg [Am] 10:613–618 .
4. Broadbent TR, Woolf RM (1964) Flexion-adduction deformity of the thumb—congenital clasped thumb. Plast Reconstr Surg 34:612–616. [PubMed]
5. Shaw DT, Ricky DG, Nahigian JH (1973) Interdigital butterfly flap in the hand (the double-opposing Z-plasty). J Bone Joint Surg Am 55:1677. [PubMed]
6. Buck-Gramcko D (1998) Congenital malformations of the hand and forearm. Churchill Livingstone, London .
7. Abdel Ghani H (2006) Modified dorsal rotational advancement flap for release of thumb web space. J Hand Surg [Br] 31(2):226–229 .
8. Lin SC, Hung TH, Hsu HY, Lin CG, Chiu HY (1999) A simple splinting method for correction of supple congenital clasped thumbs in infants. J Hand Surg [Br] 24:612–614 .
9. Flatt AE (1994) The care of congenital hand anomalies. 2nd ed. Quality Medical Publishing, St. Louis .
10. Weckesser EC, Reed JR, Heiple KG (1968) Congenital clasped thumb (congenital flexion-adduction deformity of the thumb). J Bone Joint Surg Am 50:1417–1428. [PubMed]
11. Beals RK (1973) Trico-rhino-phalangeal dysplasia. report of kindred. J Bone Joint Surg Am 55:821–826. [PubMed]
12. Cervenka j, Figalová P, Gorlin RJ (1969) Cranio-carpo-tarsal dysplasia, or the whistling face syndrome II. Oral intercommissural distance in children. Am J Dis Child 117:434–435. [PubMed]
13. Christian JC, Andrews PA, Conneally PM, Muller J (1971) The adducted thumbs syndrome. Clin Genet 2:95–103. [PubMed]
14. Freeman EA, Sheldon JH (1938) Cranio-carpo-tarsal dystrophy. An undescribed congenital malformation. Arch Dis Child 13:277–238 .
15. Gilly RJ, Cotton S, Farouz A, Nairet A, Maclet M (1971) Hydrocéphalie congénitale et anomalie bilatérale des pouces: Syndrome malformatif lié au chromosome “X”. Pediatrie 26: 365–378. [PubMed]
16. Janecke AR, Unsinn K, Krecxy A (2001) Adducted thumb-club foot syndrome in sibs of a consanguineous Austrian family. J Med Genet 138:265–269. [PMC free article] [PubMed]
17. McCarroll HR, Manske PR (1998) The windswept hand. In: Buck-Gramcko D (ed) Congenital malformations of the hand and forearm. Churchill Livingstone, London, pp 313–325 .
18. O’Keefe M, Crawford JS, Young JDH, Macrae WG (1986) Ocular abnormalities in the Freeman–Sheldon syndrome. Am J Ophthalmol 102:346–348. [PubMed]
19. Senrui H (1998) Congenital Contractures. In: Buck-Gramcko D (ed) Congenital malformations of the hand and forearm. Churchill Livingstone, London, pp 295–309 .
20. Weinstein S, Grolin RJ (1969) Cranio-carpo-tarsal dysplasia or the whistling face syndrome. Am J Dis Child 117:427–433. [PubMed]
21. Wood VE (1994) Another look at the causes of the windblown hand. J Hand Surg [Br] 19:679–682 .
22. Dundar M, Demiryikmaz F, Demiryikmaz I (1997) An autosomal recessive adducted thumb-club foot syndrome observed in Turkish cousins. Clin Gene 51:61–64 .
23. Hall J (1981) An approach to congenital contractures (arthrogryposis). Pediatr Ann 10:15. [PubMed]
24. Pozanski AK, LaRowe PC (1970) Radiographic manifestations of arthrogryposis syndrome. Radiology 95:353. [PubMed]
25. Sonoda T, Kouno K (2000) Two brothers with distal arthrogryposis, peculiar facial appearance, cleft palate, short stature, hydronephrosis, retentio testis and normal intelligence: a new type of distal arthrogryposis? Am J Med Genet 10:280–285. [PubMed]
26. Fitch N, Levy EP (1975) Adducted thumb syndromes. Clin Genet 8:190–198. [PubMed]
27. Mih AD (1998) Congenital clasped thumb. Hand Clinics 14:77–84. [PubMed]
28. McCarroll HR (1985) Congenital flexion deformities of the thumb. Hand Clin 1:567–575. [PubMed]
29. Lipskeir E, Weizenbluth M (1989) Surgical treatment of clasped thumb. J Hand Surg [Br] 14:72–79 .

Posted by at No comments:
Subscribe to: Posts (Atom)