Severe upper extremity and hand injuries have significant morbidity and economic impact. Replantation is the reattachment of a completely amputated body part, including restoration of arterial inflow and venous outflow. Revascularization is the restoration of arterial inflow and venous outflow. With the high survival rates of the replanted or revascularized amputated part in posttraumatic amputations, the emphasis has recently shifted from survival to the functional recovery of the repaired part. Not all patients benefit from replantation or are suitable candidates for replantation. When a replantation decision is taken and preparation is being made, we encounter three important situations. These are factors belonging to the surgical team, factors related to the patient, and factors related to the injury. Skin, vessels, nerves, muscles and tendons, and bone should be evaluated in five groups separately in the amputation and stump, and an operation plan should be formed. Replantation of injuries proximal to the level of the radiocarpal joint is referred to as major upper limb replantations, including amputations at the level of the wrist, forearm, elbow, humerus, or shoulder. In major upper limb replantations, aggressive debridement of the stump and amputated parts should be performed under tourniquet control. There is still no consensus on the reconstruction sequence (bone before vessel or the reverse), which is still controversial in the literature. If the time from amputation to arrival in the operating room is longer than 4–6 h, a temporary vascular shunt can be performed before bone fixation to restore arterial flow within the amputated part. Postoperative physical therapy, rehabilitation, and postoperative monitoring are as important as the operation for functional recovery and a successful outcome. Complications can be divided into acute, subacute, and late complications. The most common cause of failure in major limb replantation is arterial thrombosis because of myonecrosis and infection. A successful replantation can significantly improve the patient’s quality of life and help them regain physical function. With appropriate surgery and subsequent rehabilitation, favorable outcomes can be achieved in many patients.