Autologous bone grafting may or may not be necessary in this setting. If needed, iliac crest has been utilized as the conventional harvest site for cancellous bone. When operating on the lower extremity, the proximal tibial metaphysis is a convenient source of autograft, but this may be difficult if the proximal tibia is the focal point of the established nonunion. However, when working on a lateral articular nonunion, the medial metaphysis may be used as a source, and when working on lateral side, medial graft may be collected. Once placed within the metaphyseal nonunion site, the bone graft may be so bulky as to be an impediment to anatomic reduction of a partial articular fragment, and in this case, the graft must be packed into a vacancy in the metaphysis, or not utilized.

Once anatomic reduction is achieved, clamps may be utilized to provisionally stabilize the nonunion and provide compression. Buttress fixation then relies on a well-contoured, or even slightly “under-contoured” plate, with the initial point of fixation being just distal to the apex of the nonunited fragment. If the patient is especially osteopenic, due to age, disease, or prolonged nonweight-bearing, cortical purchase of the buttress screws may be compromised, requiring the use of locking fixation. Otherwise, nonlocking fixation should be ideal for this indication, and lag screws may be used, either through the plate or around the plate, for further rigid fixation of the nonunited articular fragment (see Fig. 12.1d).

Extra-articular nonunion of the proximal tibia presents a wider array of treatment options. Given the location, both hypertrophic and oligotrophic nonunions would likely benefit from compression in this area, but this can be achieved with nailing, plate and screw constructs, or circular frames.

As discussed earlier, correction of alignment is of the highest priority in addressing proximal tibial nonunions. Extra-articular nonunions will usually feature deformity in one or more of these planes (coronal, sagittal, rotational). In the author’s experience, autogenous bone graft is routinely utilized for almost all of these nonunions.

The two most important variables in determining the ultimate method of fixation are (1) the size of the proximal segment and (2) the degree of deformity. For larger proximal segments, where adequate fixation may be achieved with an intramedullary device, this method may be preferred (Figs. 12.2 and 12.3 ). Blocking screws may be employed to maintain correct alignment and enhance stability, and a variety of methods may be used to achieve compression with an intramedullary rod. Blocking screws are generally left in place at the conclusion of the operation (as opposed to removing them after rodding) to help maintain alignment as the fracture heals. Compression may be achieved by locking the rod distally first, and then “backslapping” the intramedullary rod, or via compression devices applied through the application jig of many nail systems. Another method for compression over a rod is dynamic locking, but this may not be recommended in the setting of a potentially less stable metaphyseal nonunion.

Smaller articular-epiphyseal segments may be better captured and compressed with either locking plate constructs or with Ilizarov techniques. The degree of deformity may drive choice of fixation based on (1) suitability of implants to the corrected deformity or (2) the pliability of soft tissue coverage at the concavity of the nonunion. For difficult soft tissue coverage situations, circular frame correction over time may allow for gradual correction and slow expansion of the soft tissue envelope. This technique may also be helpful in the setting of questionable patient compliance, as a circular frame may permit immediate weight bearing (Fig. 12.4). For small peri-articular blocks, the author prefers dual locking plates applied separately through two incisions, but familiarity with Ilizarov techniques is required if soft tissues will not tolerate immediate on-table complete correction of alignment.

To utilize locking plates for small peri-articular blocks, start with adequate debridement of the metaphyseal nonunion site and correction of alignment. Alignment correction may be aided with an AO (Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation) universal distractor, or by leveraging the plates that will ultimately be used for fixation. The author prefers to establish proximal locking fixation both medially and laterally before imparting compression and final fine-tuning of alignment. Balanced compression of each plate may then be used to fine-tune coronal plane alignment (Figs. 12.5 and 12.6 ). Intraoperatively, fluoroscopy may not be able to adequately confirm coronal plane alignment, and this may require an intraoperative plain radiograph before finalizing the distal fixation (see Fig. 12.6c).