The deformities of the fingers and toes

by William Anderson

We may then define hammer finger as the result of a developmental irregularity of the first or second inter-phalangeal joint (rarely of the metacarpo-phalangeal joint) by which the anterior fibres of the lateral ligaments become prematurely tense during extension, and so check that movement before it attains its normal physiological limit. It is precisely analogous to hammer toe; but it is of less frequency than the latter affection, because while civilisation sedulously cultivates the freedom and precision of action in the fingers, it devises foot-coverings to repress the natural play of the toes. The tendency to the deformity may be transmitted by descent through an indefinite number of generations.

Diagnosis.—Spurious hammer finger, like false hammer toe, may occur from—(1) articular lesions due to rheumatism, rheumatoid arthritis, gout, tuberculosis, and inflammations of traumatic origin; or (2) from interference with the muscular functions by paralysis of the extensors or by spastic contraction of the flexors. In the first group the joint will be found in a more or less complete state of ankylosis, movements in all directions being impeded. In the second group the articulation, although contracted, is freely mobile under passive force, unless, as in some congenital paralyses, irregularities of development in the articulations be superadded.

Treatment.—The treatment of hammer finger is a far less simple problem than that of hammer toe, because in the toe the sacrifice of the movement of the affected articulation does not sensibly impair the utility of the digit, while in the fingers an ankylosis of the first inter-phalangeal joint in the position of either flexion or extension would be even more inconvenient than the ligamentous contraction. The measures available are (1) passive movement; (2) subcutaneous section of lateral ligaments, with or without tendon lengthening; and (3) amputation. In the milder cases a persevering use of passive motion will in time effect a cure; but when the contraction has reached an advanced degree it may be impossible to make an impression by this means. We may then divide the lateral ligaments, and keep the fingers straight by means of an extension splint while the tendons are relaxed by flexion of the wrist, trusting to subsequent massage and passive motion, or, failing this, to tendon lengthening (by a process to be described later), to overcome the resistance of the shortened muscles. Section of tendons within the theca is useless, because no uniting material is thrown out between the divided ends. As a last resource, amputation may be demanded to remove a useless and inconvenient member.

Lateral versions of the phalangeal joints.—Lateral versions of the fingers are intimately associated with hammer finger in pathology, and the two distortions are sometimes combined. The lateral inclination, which seldom exceeds 25°, may affect either of the inter-phalangeal joints, but is more frequently in the distal phalanx. Like the “hammer” deformity, it is usually found in the little finger, and is symmetrical. The version is nearly always towards the radial side, and the movements of the joint are a little impaired. Amongst eight hundred children in the Hanwell School were found six cases, of which five were double and affected the little fingers, the sixth being in the fourth digit and unilateral; in two the version was associated with slight hammer flexion. It is occasionally seen in the index finger, and the version is then towards the ulnar side. The condition is rather unbecoming than inconvenient, and cases are seldom brought to the surgeon for relief. It is a result of irregularity of development, the condyle growing a little more rapidly on one side than on the other. The constancy of the radial direction of the version of the little finger is probably explained by the fact that any lateral pressure to which this digit is subjected is from the ulnar side, while in the index finger the pressure is more often from the radial side, and hence an ulnar distortion is here the more usual. The deflected joint may be straightened by the use for a few weeks of a narrow metallic side splint, jointed opposite the articulations. No operation is required.

Exaggerated forms of distortion of the fingers may occur in rheumatoid arthritis, gout, or chronic rheumatism, and in various nervous affections,[2] but these rarely call for surgical treatment.

CONTRACTIONS ARISING FROM INTERRUPTED EVOLUTION OF THE FLEXORS OF THE FINGERS, WITHOUT PARALYTIC OR SPASTIC COMPLICATIONS.

This condition necessarily belongs to the pre-adult stage of development. It is characterised by persistent flexion of one or more digits, without any articular abnormality, and unassociated with spasm or paralysis, but the contraction is of a different kind from that found in hammer finger and hammer toe. The degree of flexion varies with the position of the hand, and when the wrist is strongly bent forwards the fingers may be extended, perhaps completely, but extension of the wrist is accompanied by a return of the contraction, the degree of which increases progressively as the wrist extension is carried nearer to its limit. The power of grasp is little impaired. Any attempt to overcome the flexion by violence is met by powerful resistance, and great pain is induced. If the patient be anæsthetised, the contraction remains unaltered, but the resistance is felt to be of a peculiar elastic character, and yields to a slight extent during the application of passive force. The defect leads to great interference with the functions of the hand. The pain caused by anything that tends to stretch the shortened muscles induces a voluntary exaggeration of the flexion, and after a time the control over the extensors is apt to become impaired. The causes are often obscure, but some examples have been traced to traumatic injuries of the flexor side of the forearm in infancy or childhood. In any case the essential factor appears to be a trophic lesion of local or central origin, which retards or arrests the due growth of a muscle or a portion of a muscle without causing its atrophy or paralysis. The following cases will serve to illustrate the phenomena so far as they have come under my own observation:

Case 1.—M. O., a domestic servant aged seventeen, was admitted into St. Thomas’s Hospital in September 1889. On examination the third, fourth, and fifth fingers of the right hand were found to be flexed at the metacarpo-phalangeal and inter-phalangeal joints—the two latter strongly, the former slightly. When the wrist was fully extended the contraction became more marked, and the distal phalanges of the ring and little fingers touched the palm, but when the wrist was fully flexed the fingers could be voluntarily brought into a state of complete extension. The power of grasp was good, although somewhat less than in the left arm; the bones were normal in form and size; and the joints were quite free in their movements when the flexors were relaxed by position. The forearm muscles appeared to be of normal size. A small scar was seen about two inches below the elbow, over the inner side of the front of the arm, the result of a fall thirteen years before. The patient was strong and healthy in appearance, and showed no sign of neurotic disorder. She had never suffered from rheumatism or any other severe illness, and the family history appeared to be good. She stated that the contraction began to appear in childhood, shortly after the injury to the arm, but that it had been making more rapid progress in the past eighteen months, during which she had been growing very quickly. After a fruitless attempt to improve the condition by passive motion and splint extension, neither of which was well borne, it was determined to lengthen the tendons by operation. On October 18, 1889, the patient was chloroformed, and it was observed that the deepest anæsthesia caused no relaxation of the contraction. A semicircular incision was made over the inner side of the front of the forearm just above the wrist, the convexity overlapping the tendon of the flexor carpi ulnaris, the horns reaching to a line midway between the radial and ulnar borders of the limb. The flap of integument and fascia was reflected towards the radial side, exposing the inner portion of the flexor sublimis. The tendon of this muscle going to the ring finger was then isolated, transfixed by a fine tenotomy knife, and split longitudinally for a distance of two inches. At each end of the fissure so made the tendon was divided in such a manner as to leave one-half of the split portion attached to the proximal, the other to the distal, end of the tendon. ([Fig. 8.]) The tendon, a very slender one, to the little finger was similarly treated. The effect of this measure upon the contraction was very slight. The portion of the flexor profundus common to the middle, ring, and little fingers was then drawn out and divided after the same method, and the section was followed by immediate and complete extension of the digits. When the fingers were fully straightened, the ends of the divided tendons still overlapped each other to the extent of about a third of an inch, and these portions, in each tendon, were then carefully sewn together by catgut sutures. The wound was then closed and dressed antiseptically (without drainage), and the hand was placed upon a plaster-of-Paris splint; the wrist and fingers being moderately flexed, in order that no undue tension should be thrown upon the united tendons. Healing took place by first intention. At the end of a week the fingers were partially extended, and four days later the extension was made complete, the alteration of position on each occasion being effected without difficulty, and at the expense of little pain. In the middle of the fourth week after the operation a feeble power of flexion had appeared. The patient was discharged on November 13, twenty-six days after the operation. Two months later the condition had much improved, and the voluntary flexion, although still weak, was almost complete as to range. All the tendons had evidently united firmly. She was directed to wear an extension splint at night, and to practise active and passive movement at intervals in the day-time. At the end of a further three months the patient, who lived in the country, came again to London. She had been growing taller in the interval, and said that the contraction had been gradually reappearing. On inquiry it was found that she had neglected her instructions as to extension and motion. Some slight return of the flexion had appeared in the ring and little fingers, and has since been steadily increasing, till it is now almost as great as when she first attended. She has made no adequate effort to oppose the retrogression, but has almost entirely discontinued to use the affected hand. She is still, however, able to move the fingers freely at all the joints. She desires to undergo another operation; but has been advised to obey the directions given to her after the first, and to wait until her growth is quite complete before any more active surgical treatment is undertaken.

Fig. 8.