Different reconstruction methods can be selected according to the degree of defect and functional requirements.

(1) interphalangeal joint defect (I degree defect)

Part of the function of thumb is still preserved, which is not needed for special occupations and generally does not need treatment.

(II) Defect of the middle segment of the proximal phalanx

The saved thumb length is short, which has a great influence on the function. You can choose the following methods to improve thumb function.

1. Deepen in the abyss of death

The length of the thumb can be relatively extended. The method is to cut the skin of the tiger's mouth into a Z shape, cut off the contracture of the adductor pollicis, and transfer the dorsal index finger flap to deepen the tiger's mouth if necessary.

2. Cap lifting method

Also known as degloving bone grafting. Suitable for those who have left the proximal phalanx of 1/2 or 1/3 and the skin of thumb stump is slack. Methods: the skin was cut 3 ~ 4 cm away from the stump and the nerves, arteries and veins were released to the proximal end. The full-thickness free distal flap was used to form a hat-shaped flap, and the finger tip was transplanted. The hat-shaped flap was lifted to cover the bone end, and the proximal wound was repaired by skin grafting. This method can prolong the thumb by about 1 ~ 1.5 cm.

3. Lengthening the first metacarpal bone

The first metacarpal shaft was exposed by operation, and the metacarpal bone was cut off under the periosteum and then implanted with bone graft to prolong the metacarpal bone. Or after the metacarpal bone is cut off, a tractor is installed to close the wound, and the metacarpal bone is extended day by day for secondary bone grafting.

4. Free transplantation of the second toe with plantar artery as the blood supply artery to reconstruct the thumb. The appearance and function of this method are satisfactory.

(3) metacarpophalangeal joint or partial metacarpal bone defect (Ⅱ ~ Ⅲ degree defect)

The thumb is completely missing, leaving only the first metacarpal bone or part of the metacarpal bone, and the thenar function exists partially or completely. According to the specific situation, choose the following methods:

1. thumb reconstruction by transferring adjacent residual fingers

Thumb reconstruction with incompetent adjacent fingers should be the first choice. It is required that the transferred residual finger has good circulation and feeling, and the nerve and blood vessels are not damaged. Its design purpose is to transplant the residual finger with appropriate length to the first metacarpal bone together with tendons, nerves, arteries, veins and soft tissues around blood vessels. Kirschner pins cross and fix the bone in the opposite palm position, so that it contacts with the pulp of each finger. This method does not need to cut off nerves and blood vessels, and can form a thumb with good sensory and motor functions and satisfactory appearance.

2. thumb reconstruction by free transplantation of the second toe

1966 was invented by Yang Dongyue of China, which provided an ideal new method for thumb reconstruction. This method can add one finger, which is suitable for the second and third degree defect of thumb, especially for those with more than two fingers. In addition, people with four fingers defects can also reconstruct their fingers by this method. The free second toe can also provide fingers for hand reconstruction.

The second toe is long and its shape is close to the thumb. Removing the second toe and the second metatarsal bone has little effect on walking function and shape. Methods The skin was cut as shown in the figure, and the dorsal artery of the foot, great saphenous vein, flexor digitorum, extensor tendon and toe nerve were dissociated to the distal end, then cut off at high position, and the metatarsophalangeal joint or metatarsal neck was severed, and the toe was completely dissociated and transplanted to the thumb. The metacarpal bone was fixed with Kirschner wire and anastomosed with flexor tendon, extensor tendon, digital nerve, radial artery and cephalic vein respectively, and the reconstruction operation was completed at one time. The reconstructed thumb not only has good appearance, satisfactory sensory and motor functions, but also has high technical requirements.

In recent years, someone used a similar method to reconstruct thumb with free toenail flap and iliac bone transplantation, and obtained a good thumb, but it had a great influence on foot function.

3. Transfer normal index finger to reconstruct thumb

Also known as thumb pointing. For second and third degree thumb defects, if the thumb cannot be reconstructed by the above method, the normal index finger can be transferred. The advantage of this method is that it retains the continuity of nerves, blood vessels and tendons, and it is easy to succeed. The reconstructed thumb has good sensory and motor functions. Its disadvantage is that it is more expensive to use the normal index finger, and the surgical method is the same as the transfer of the residual finger, but pay attention to the length of the thumb, not too long.

4. thumb reconstruction with skin tube and bone graft

The method is to transplant the first metacarpal stump, implant a skin tube (such as subclavian skin tube), and break the pedicle after 3 ~ 4 weeks to form a thumb. The thumb reconstructed by this method has poor circulation, frequent frostbite or scald, and poor function. Now it has been basically abandoned and only used in some cases. In order to improve the sensory function, the island flap with neurovascular pedicle on one side of the ring finger can be taken out and transferred to the thumb skin tube (usually the fingertip and ulnar side) to make the area feel good.