Open reduction and internal fixation for fracture-dislocation of the first metacarpal base

The first metacarpal base fracture (bennett fracture) is an unstable fracture. Anatomically, the first metacarpal and the multi-corner bone form a saddle joint, which is flexible and stable. When the violence acts on the saddle-shaped nodule along the longitudinal axis of the thumb, an oblique fracture from the top to the bottom of the first metacarpal can be formed. . The proximal fracture block can maintain an anatomical relationship with the horny bone due to the attachment of the ligament and the joint capsule. The distal fracture segment is displaced to the temporal and dorsal side due to the traction of the abductor pollicis longus [Fig. 1(1)] . Bennett's fracture reduction is easier, and it is more difficult to maintain the contraposition. It is easy to be displaced after the reduction and deformed. Therefore, this fracture often requires open reduction. Indication 1. The first metacarpal base fracture and dislocation, unsatisfactory reset, or displaced after reset. 2. After 1 to 2 weeks of fracture or old fracture, there is difficulty in reduction and external fixation. Preoperative preparation 1. It is very important to routinely perform limb traction before surgery to return the femoral head from the posterior superior aspect of the acetabulum to the acetabular level. Traction can relax the contracted muscles, on the one hand, it can make the operation reset easily and prevent postoperative dislocation; on the other hand, it can reduce the cartilage surface necrosis and avascular necrosis of the femoral head after compression of the femoral head. opportunity. Older, dislocated children can be used for traction; older age should be treated with humeral traction. Generally, the femoral head can be lowered to the acetabular plane after 2 to 3 weeks of traction. After the X-ray film is confirmed, the weight can be appropriately reduced, and the femoral head can be maintained in the plane for 1 to 2 weeks. 2. If the traction of the femoral head is not obvious, it should be checked whether it is caused by the contraction of the femoral or gluteal muscles. In this case, the adductor muscle starting point should be cut or released, and then the limbs should be pulled to meet the traction requirements. Generally speaking, those who are more than 2 to 3 years old need to be cut off and can be released. 3. Preoperative cases were prepared for skin around the hip joint and lower limbs for 3 days. 4. Preoperatively, the anteversion angle, the hip valgus angle, the selected capping site, the hip osteotomy site, and then the surgical design of the femoral or hip bone osteotomy angle and the size of the bone graft should be determined. 5. Prepare blood 200 ~ 600ml. Surgical procedure 1. Position the patient in the supine position, the injured limb is abducted on the small table; or the injured limb is placed on the chest. 2. The incision is from the middle of the first metacarpal 1/3, along the lateral side of the metacarpal and the side of the large fish muscle tendon to the proximal side, to the transverse stripes of the wrist, along the horizontal line to the ulnar side, so that the incision is l-shaped. 3. Expose the fracture end to open the skin, subcutaneous and fascia, on the dorsal side of the incision, visible flexor tendon of the thumb, and pull it away from the dorsal side. The periosteum and joint capsule were cut at the proximal end of the first metacarpal for subperiosteal dissection to reveal the proximal metacarpal and fracture sites. 4. The reset assistant fixes the injured hand. The operator grasps the injured person's thumb and pulls the first metacarpal abduction and extension, while pressing the base of the first metacarpal with the other thumb to reset the fracture. 5. After the internal fixation is reset, the Kirschner wire with a diameter of 1 mm is usually used for internal fixation. Under the maintenance of the assistant, if the proximal fracture block is larger, the two Kirschner wires are inserted by hand and the distal fracture segment is fixed with the triangular bone block. If the proximal fracture block is small and difficult to fix with a Kirschner wire, the thumb can be placed in the abduction to the palm position, and the distal segment of the metacarpal bone and the large angle bone are fixed with a Kirschner wire. Because the proximal fracture of the bentnett fracture is easily displaced after the reduction, the Kirschner wire should be checked for correctness before fixation. So as not to fix the fracture block under displacement, resulting in malformation. After the internal fixation is completed, the layer is sutured layer by layer, and the tail of the Kirschner wire is bent into a hook shape and buried under the skin.

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