The patient is placed in a lateral position on a radiolucent operation table. Alternatively, a fracture table can be utilized with the patient in supine position. Perioperative antibiotic prophylaxis is administered only after bacterial swaps from the extracted nail and reaming material have been taken.

As a first step, the extraction device is inserted into the nail tip and interlocking screws are removed. Nail extraction is done cautiously to prevent contact of the extracted nail with the skin in order to avoid secondary contamination.

Following nail removal, a guide wire is gently bent at the tip and is inserted into the intramedullary canal. Care is taken to precisely position the guide wire into the center of the femoral intercondylar region assessed by anteroposterior and lateral radiologic views. By this cautious procedure, perfect axis alignment of the femoral shaft can be expected after successful femoral nailing. Obviously, a correct insertion point of the nail is also very important. A new insertion point has to be chosen in case the previous one was malpositioned. A poller screw which is placed in the entry path of the previous nail prevents the new nail to slip back into the old wrong nail path (see also Fig. 19.​41). Sequential reaming is performed using incremental increase of drill bits with the goal of inserting a nail which has a diameter of 2 mm more than the initial nail diameter, or at least 12 mm. Therefore, in the isthmal region the intramedullary canal is over-reamed with 2 mm more than the determined, final nail diameter. It is ensured that the new nail has good cortical contact and a snug fit and that any fracture gap or dehiscence is avoided.

For exchange nailing, we utilize a compression nail offering the possibility of interfragmentary compression. Distal interlocking screws are inserted first. Consecutively, the proximal interlocking, placed in the dynamic hole, is put under compression by tightening the compression screw, which is inserted proximally in the nail. Before proximal interlocking and compression are performed, we assess femoral torsion radiologically. The femoral condyles are assessed in the lateral view where both condyles project precisely over each other. The C-arm is fixed in all directions and then moved horizontally and centered over the region of the femoral head. Torsion of the femur is considered acceptable if the femoral head projects anterior to the axis of the femoral shaft with two thirds of its circumference. Intraoperative radiological assessment of torsion with the above described method is easier in the lateral than in the supine position. The operative procedure ends with anteroposterior and lateral views of the femur including the adjacent knee and hip joint.

Postoperatively, patients receive physiotherapy and are mobilized out of bed immediately. Weight bearing as tolerated is permitted. Sequential radiologic follow-up studies are done at regular intervals at 6 and 12 weeks as well as 6 months postoperatively.

In 50 femoral shaft nonunions following intramedullary nailing, reamed exchange nailing was performed at our Trauma Center. We found a hypertrophic nonunion in 83 %. In 85 %, exchange nailing was done as a closed procedure. In 89 %, only one procedure was required. Healing was achieved in 95 % of patients. The median time to healing was 4.3 months.

In 2009, Shroeder et al. reported an 86 % union rate in a group of 42 patients with femoral shaft nonunion after previous intramedullary nail osteosynthesis. Only 14 % required additional procedures [21]. Similar excellent results had already been published in the 1980s by Kempf et al. and Webb et al. [31, 22].

However, two studies reported disappointing results of bone healing following closed nonunion treatment with a success rate of 73 and 58 % respectively [32, 33]. The authors concluded that the treatment of femoral shaft nonunion should include open resection of nonunion tissue and insertion of an auxiliary plate at the nonunion site to increase rotational stability. We are of a different opinion. The results of our study suggest, that open nonunion treatment is not required. The disappointing results in the studies of Banaszkiewicz and Weresh may be attributed to the lack of systematic microbiological analysis. Even in the absence of macroscopic evidence of infection, low grade infection may contribute to treatment failure. We therefore routinely harvest bacterial samples from the reaming graft as well as obtained intraoperative material for culturing in thioglycolate culture medium [21].

Delayed bone healing or persistent nonunion following exchange nailing may require repeated stimulation by performing a second exchange nailing procedure including additional reaming of the intramedullary canal, distributing intramedullary reaming graft, and insertion of an even thicker and more stable nail, e.g. nail diameter up to 14 or 15 mm.

Reamed exchange nailing can be considered as the treatment of choice for nonunion of femoral shaft fractures. A single and closed operative procedure leads to bone healing in most cases. Limited correction of axis deviation is possible without opening the nonunion site. Additional surgical damage to the soft tissues is avoided and there is a lower operative morbidity. The increased stability of a thicker nail results in high postoperative patient comfort and a low pain sensation and allows for early unrestricted weight bearing and active rehabilitation.

A distal femur shaft nonunion following retrograde nailing may be treated with exchange antegrade intramedullary nailing. If the distal femur segment is long enough to anchor 3 distal interlocking screws, then insertion of a strong antegrade nail with interfragmentary compression is a valid treatment option (Fig. 25.6a–q).

Obviously, closed exchange nailing and the central position of the nail in the intramedullary canal are offering a biological stimulus and the biomechanical advantages of providing central load transmission and optimal resistance to axial forces. The closed reduction technique is preserving the soft tissue envelope around the nonunion area.

For the treatment of metaphyseal femoral nonunion following retrograde intramedullary nailing, exchange nailing and reinsertion of another retrograde nail, even with an increased nail diameter has resulted in relatively high failure rates and persistent nonunion. Therefore, retrograde exchange nailing cannot be recommended as a standard concept, but conversion to a stable locked plate fixation preferred. For biological augmentation, cancellous bone autografts and bone morphogenic proteins BMP-7 or BMP-2 are utilized [17, 18].

Reamed intramedullary nailing is an excellent method of treatment for aseptic tibia nonunion after unreamed nailing or plating in closed, and grade I or II open fractures, which is localized in the middle three fifths of the tibia [42]. This technique has the advantage of providing high stability, maintenance of alignment; and enables early weight bearing and quick rehabilitation. The reaming debris serves as internal bone grafting and renders an open resection of the nonunion site dispensable.

In hypertrophic nonunion, e.g. following nailing of a tibia shaft fracture using an unreamed and unstable nail with thin interlocking bolts, closed exchange nailing can be performed by insertion of a stronger reamed intramedullary nail, preferentially with compression. The procedure of exchange nailing can be performed with the patient in supine position using a normal or a fracture table. The fracture table allows for distraction, and may facilitate reduction and axis alignment. If axis deviation of the tibial nonunion requires correction, a limited open approach and correction osteotomy may be required.