On dissection, it is found that the contracture is maintained by shortening of the plantar portions of the collateral ligaments of the first inter-phalangeal joint and of the glenoid ligament upon which the head of the first phalanx rests.
Hammer-toe is usually ascribed to the use of tight socks and of ill-fitting boots, especially those which are median-pointed and are too short for the feet, but in some persons there appears to be an inherited predisposition to the deformity.
Fig. 161.—Section of Hammer-toe.
a, Corn.
b, Bursa over first inter-phalangeal joint.
While corrective manipulations, strapping, and the use of splints may be of service in slight cases, it is usually necessary to perform an operation in order to extend the toe permanently. Before operating, any infective condition, such as a suppurating corn or bursa, must be corrected. The collateral and glenoid ligaments are divided subcutaneously—Spitzy also divides the flexor tendons and capsule—and if the toe can then be straightened, the foot is secured to a metal splint moulded to the sole and provided with longitudinal slots opposite the intervals on either side of the toe affected. The toe is drawn down to the splint by passing a loop of cotton or elastic bandage round the toe and through the slots. In many cases the contraction of all the tissues on the plantar aspect, including the skin, prevents the toe being straightened even after division of the ligaments, and it is then necessary to remove the head and neck of the first phalanx through a lateral incision. This is more satisfactory than amputation of the affected toe at the metatarso-phalangeal joint, as after this the adjacent toes tend to fall together and favour hallux valgus. If amputation is performed, a pad of cotton wool or rubber prop should be worn to fill up the vacant space.
The term Gampsodactyly has been applied to a deformity in which all the toes assume the position of hammer-toe, usually from a spastic condition of the muscles controlling the toes.
Hypertrophy of the Toes.—One or more of the toes may be the seat of hypertrophy or local giantism. This is usually present at birth or appears in early childhood, and may form part of an overgrowth involving the entire lower extremity ([Fig. 162]). The overgrowth may involve all the tissues equally, or the subcutaneous fat may be specially affected. The medial toes are those most commonly hypertrophied. In addition to being enlarged, the toe may be displaced from its normal axis. The hypertrophy may affect two or more toes which are fused together or webbed ([Fig. 162]). The treatment consists in amputating as much of the toe as will allow of an ordinary boot being worn.