Introduction and Definitions
Pathophysiology and Etiology
Infection as a Factor
Evaluation and Diagnosis
History and Physical Examination
Laboratory Studies for Diagnosis
Objectives and General Principles
Soft Tissue Management
Indications and Contraindications for Nonoperative and Operative Treatment
Adjuncts to Operative Nonunion Repair
Autogenous Bone Graft
Bone Graft Substitutes and Other Modifiers of Bone Healing
Graft Site Preparation
Managing Articular Nonunion
Managing Segmental Bone Loss
Management of Infected Nonunions
Management of Soft Tissue Compromise
Author’s Preferences in the Treatment of Nonunions
Nonoperative Nonunion Treatment
Operative Treatment of Nonunion
External stimulation alone, typically ultrasound, is reserved for patients who are minimally symptomatic from their nonunion and who are not candidates for surgery or additional procedures (Fig. 27-28). Ultrasound stimulation is sometimes used in conjunction with operative treatment in high-risk patients such as smokers and diabetics.
Septic nonunions are one of the most challenging reconstructive procedures facing the orthopaedic traumatologist. These patients deserve the expertise of a team fluent in their management. Often, infected nonunions are limb-threatening conditions. Given the seriousness of this condition, our approach is to maximize the treatment decisions toward eradicating infection. Therefore, hardware removal, wide debridement, soft tissue coverage as needed, culture-specific local and IV antibiotics, and bony stabilization are utilized in the initial phase of a multistage management protocol. Local antibiotic delivery is typically with antibiotic beads between serial debridements and with antibiotic PMMA spacers or antibiotic rods after definitive closure. Stabilization is with an antibiotic rod when applicable (e.g., diaphyseal tibia nonunion), otherwise with external fixation.
The second phase of management is dedicated to treatment with IV antibiotics and monitoring. We rely on an infectious disease team experienced in the management of osteomyelitis to direct the selection and duration of antibiotic therapy and manage any encountered side effects. The second phase ends when clinical, laboratory, and radiographic signs of infection are absent, usually after 6 weeks of therapy.
The third phase in the management of infected nonunions typically mimics the management of atrophic aseptic nonunions as discussed in the following section. One important decision at this juncture is whether to discontinue antibiotic therapy prior to nonunion repair or to continue therapy through and after nonunion repair. We generally lean toward continuation of oral therapy until union has occurred whenever there is any doubt regarding the success in eradication of infection.
The first consideration when dealing with nonviable or marginally vital nonunions is whether direct compression of the bone ends is possible without unacceptable shortening. When the answer is yes, then compression with a nail or plate is desired unless the soft tissues dictate the need for thin wire external fixation. If the nonunion is well aligned, then the choice of IM nailing or plating is largely based on the location of the nonunion. Well aligned nondiasphyseal nonunions, in the absence of bone loss, are preferably managed with compression plating. Diaphyseal nonunions without bone defects are preferably managed with primary IM nailing or exchange nailing (if a nail was previously used) if well aligned. If the nonunion is malaligned, compression plating is preferred regardless of location. When direct compression of atrophic nonunions can be accomplished without any remaining defects, we find it unnecessary to add bone graft. This is an unusual circumstance most commonly encountered when dealing with humeral and clavicle nonunions. When direct compression still leaves some bony defect, autologous cancellous bone is our primary choice of graft material. Cancellous allograft combined with BMP is a reasonable alternative. We find no utility in grafting atrophic nonunions with allograft alone.
When bone defects are present we prefer to fill the defect with autologous bone graft when available in sufficient quantities. Graft from the iliac crest harvested with an acetabular reamer and graft harvested from the femur using the RIA system have been found to be equally effective in our experience. When the volume of autologous graft is insufficient to fill the defect, we preferentially use cancellous allograft to expand the volume. As a rule of thumb, a ratio of autograft to allograft of up to 1:2 is acceptable. When greater relative quantities of allograft are expected to be required, bone transport methods rather than direct void filling is generally utilized. We prefer to think of the autologous and allograft mixture as being one of three grades. Grade A graft is pure autograft. This has the greatest potential for healing and is used in the most important regions of the nonunion, typically at the periphery. Grade B graft is a mixture of autograft and allograft. This has intermediate biologic potential for healing and is used centrally to fill the medullary canal of long bone nonunions. Grade C graft is pure allograft. It has the least potential for healing of the three grades and it is used sparingly and in locations that are the least important for rapid healing. Fixation in the presence of a filled defect is either with an IM nail or a bridge plate.
Hypertrophic nonunions are simply realigned if necessary, then stabilized and when possible, compressed (Fig. 27-2A and 27-2D). The choice of implant depends upon the location of the nonunion and limb alignment. Well aligned hypertrophic nonunions at the end segment of long bones or of flat bones are preferably managed with plating. Hypertrophic diaphyseal nonunions are preferably managed with primary IM nailing or exchange nailing (if a nail was previously used) when well aligned. If the nonunion is malaligned, plating is preferred regardless of location (Fig. 27-29).