While early complications related to management of the bone are rare, anticipation of outcomes such as nonunion and malunion should direct decision making in an attempt to avoid secondary procedures. One of two possible scenarios will occur, either the amputation involved or destroyed part of a joint or the damage is primarily extra-articular. In cases of joint damage or loss, primary arthrodesis may be indicated. Techniques for achieving rigid fixation in either of these settings are well described in the chapters devoted to replantation at each level of the extremity. The replant surgeon should emphasize that, if possible, any joints that must be immobilized by fixation techniques should be stabilized in the “functional position.” In the case of the metacarpophalangeal joint, this would be roughly 60° of flexion, whereas the proximal and distal interphalangeal joints should rest at 0°. To some degree, joint stiffness following replantation is inevitable; anticipating this complication may allow placement of stiffness in the best possible position to facilitate later therapy and rehabilitation.

Although most fixation methods are designed to achieve fracture control in multiple planes, occasionally, the fracture may dictate use of only a single K-wire. In this setting, periosteal repair is useful to prevent finger rotation. Furthermore, the risk of tendon adhesion may be reduced by periosteum covering the fracture site [2]. Prevention of malrotation may obviate the need for a corrective osteotomy at a later date.

Extensor and flexor tendons are repaired in this order. Because the strength of finger flexion is greater than extension, the extensor tendon repair must be reliable to avoid rupturing when the patient performs motion exercises postoperatively. By first repairing the extensor tendon, the surgeon can confirm that no gapping occurs following the limited application of stress applied by the secondarily repaired flexor tendon. Additionally, identification and careful repair of the lateral bands of the extensor tendon and intrinsic tendons at the level of the proximal phalanx should be attempted to avoid a severe flexion deformity of the distal interphalangeal joint. Details regarding optimizing specific tendon repairs are addressed in Chap.​ 2 of this book.

Prevention of vascular complications began with debridement and vessel preparation as noted above. The next step relies on optimizing the quality of the microvascular repair. At least some debate remains as to the optimal method for performing these repairs. One controversy centers on whether the arteries or veins should be repaired first during digital replantation. In more proximal amputations, which contain muscle, restoration of inflow takes precedence, and the point is moot. Some replantation surgeons champion repairing digital arteries before the veins [3, 4], which carries with it the obvious advantage of greater ease in identifying veins in the amputated part after restoring arterial blood supply. Furthermore, repairing the veins first appears to place the “cart before the horse,” assuming arterial inflow will be adequate, an assumption that may not hold true, especially in the case of avulsion/amputation. In that setting, repair of the veins may be seen as a “waste of time” [3]. The other side of the debate supports the repair of veins prior to arteries. These authors argue that it is easier to perform anastomosis on the veins before restoring arterial inflow when the surgical field is not stained with blood [5]. In our experience, venous anastomosis in the diffuse bloody field can be avoided by using an arm or finger tourniquet. Perhaps the strongest argument in favor of repairing the digital veins first is that it comprises the most difficult part of the replantation. Performing this portion first, with full vigor at the beginning of the operation, allows the surgeon to devote the attention and detail that this repair requires and avoids relegating venous anastomosis to the end of the operation when one is tired and tends to take shortcuts by not repairing as many veins as possible.

An additional question that often arises is how many veins and arteries should be repaired. In our experience, if possible, both arteries should be repaired to maximize perfusion thus reducing the risk of loss secondary to arterial thrombosis. If both arteries are impossible to repair, the dominant digital artery (the one with lager diameter in bilateral arteries) should be repaired. Ideally, two veins are repaired per artery repaired as robust venous drainage is helpful to relieve edema after replantation and is essential to obtain good digital sensibility. While it is relatively impossible to find more than four veins with diameters over 0.5 mm to anastomose in most replanted fingers [6], the diameter of the veins increases as the number of veins decreases. On the occasion of being unable to match the veins at the appropriate position of the amputated finger and the proximal finger secondary to bony shortening, the veins can be mobilized for anastomosis by dividing and ligating their branches (Fig. 13.4a, b).

Primary nerve repair is usually not difficult if the bones are adequately shortened for replantation. Prevention of complications here includes avoiding neuroma and achieving some degree of distal sensibility. In a review in 1990, Glickman found that overall mean static two-point discrimination was 11 mm in the thumb and 12 mm in fingers following digital replantation [7]. According to recent systematic reviews, the mean 2-point discrimination was on average 10 mm in the replanted fingers after avulsion injuries and 7 mm in replanted fingers after distal digital amputation [8, 9]. Nerve defects that cannot be repaired in a tensionless manner can be repaired by nerve grafts or with interposition nerve conduits immediately during the replant procedure or later on. One well-know late complication, finger pulp atrophy, is directly related to low quality of nerve repair. Therefore, precise nerve repair under the microscope is a critical component of the replantation effort.