Overview
Bone defects and segmental bone loss are among the hardest problems in orthoplastic reconstruction. In the absence of infection, union can usually be achieved even with a segmental defect, except in the most challenging hosts. Where infection is established, control and eradication normally take priority over efforts to achieve union. Every case should be individualized. Treatment decisions rest on low-level evidence, so contemporary principles and personal experience matter. (Rockwood)
Indications and Strategy
For segmental losses, Rockwood favors either the Masquelet (induced membrane) technique or primary shortening followed by lengthening. Large segmental defects can also be reconstructed with Ilizarov bone transport. (Rockwood)
Before grafting, assess the patient with careful history, imaging and laboratory studies, and set a level of suspicion for infection.
Low suspicion: proceed with a single-stage reconstruction.
High suspicion (prior open fracture, delayed wound healing, history of infection, elevated serum markers): consider a one- or two-stage plan. (Rockwood)
Mechanical stability is mandatory. Bone grafting is ineffective in the presence of mechanical instability. (Rockwood)
A good soft-tissue envelope is required (see the soft tissue coverage guide). (Rockwood)
Authors' Preferred Technique for Grafting Defects (Rockwood)
Assess infection risk before grafting, as above.
Expose the nonunion fully, usually through prior incisions, taking care not to devitalize the site with new approaches or move away from the previous scar plane. Remove any previous implant. Use a single longitudinal incision through periosteum and scar, which allows direct closure.
Excise all nonviable tissue directly with sharp dissection.
Use a high-speed burr to freshen the bone ends and any area expected to receive graft. Apply mechanical stimulation such as endosteal drilling, decortication or perforation.
Obtain a provisional reduction, and size and contour the stabilization implants before harvesting graft.
Harvest graft so that final implantation takes place within about 15 minutes. Graft activity falls at room temperature, so avoid long extracorporeal storage.
Graft grades:
Grade A: autograft.
Grade B: autograft mixed 1:1 to 1:2 with allograft (cancellous chips), placed centrally in the defect.
Grade C: pure allograft (cancellous chips or cortical struts) for very large defects, placed centrally, then surrounded by Grade B graft, and then by Grade A graft.
If augments (BMP or antibiotics) are used, mix them before grafting. The authors prefer not to use BMP.
Graft from deep to superficial, with repeated gentle compression to fit large volumes into a small area. Overly dense packing can block nutrient access to the center.
Provide mechanical stability with an intramedullary device, extramedullary plates and screws, or thin-wire external fixation.
Close watertight along the scar bed to keep the graft in place.
The Masquelet (Induced Membrane) Technique (Rockwood)
Stage 1. Debride the defect fully and fill it with a polymethylmethacrylate (PMMA) cement spacer (antibiotic-loaded in infected cases). Stabilize the bone, typically with a locked intramedullary nail for diaphyseal defects or locked plates for metaphyseal defects. The spacer prevents fibrous ingrowth, preserves the space for graft, and induces an osteogenic membrane around it.
Interval. Wait 4 to 6 weeks for the membrane to form. Give appropriate antibiotic therapy if infection was the indication.
Stage 2. Reopen the membrane surgically, remove the cement spacer, and fill the defect with generous cancellous graft. Close the membrane around the graft.
Result. Recorticalization is typically slow, over about 3 to 6 months.
Notes: the technique needs an excellent soft-tissue envelope. It is unclear whether the membrane can be induced by materials other than PMMA. Reports describe adjuncts and graft expanders: for example a free nonvascularized fibular graft combined with cancellous autograft for 5- to 14-cm femoral or tibial defects, and beta-tricalcium phosphate combined with cancellous graft. Published results are mixed, with high failure rates in some series. Secondary stabilization was associated with success in a 2017 report. (Rockwood)
Ilizarov Techniques for Bone Defects (Rockwood)
Monofocal technique. Simple compression, distraction or combined compression and distraction at the nonunion, used for nonunions without an associated defect.
Bifocal (distraction–compression). A corticotomy in an adjacent region with distraction osteogenesis (bone transport) and final compression at the nonunion site. This is the method for bone defects.
Trifocal transport. Two-level lengthening with compression at the nonunion site.
These methods have been used successfully for tibial defects for more than two decades, and circular fixators remain the undisputed gold standard for large bone defects. Computer-assisted hexapod frames (TSF) apply the same principles. A small series of postinfectious atrophic tibial nonunions managed with bifocal and trifocal transport using a hexapod frame reported union and eradication of infection in all patients.
Cable bone transport. Interest has revived in cable and wire transport to improve the complication profile. Quinnan and Lawrie described a balanced cable transport technique in 2017 (14 patients, mean defect 11.1 cm). One serious complication (anterior tibial artery division) and 11 unplanned returns to the OR were reported, 8 of them for docking-site problems. It is considered an evolving technique.
Hypertrophic nonunions (biologically active) respond to compression, distraction or both with a closed external fixator. Gradual distraction can stimulate new bone, like limb lengthening. About 1.5 cm of modest lengthening can typically be achieved this way. For more length, add a distant osteotomy. A short compression phase of 7 to 14 days before distraction can help prepare the site.
Ilizarov-type treatment of atrophic and pseudarthrosis nonunions needs the site opened and converted to fresh bleeding bone ends (or the pseudoarthrosis tissue resected). Advocates may substitute a corticotomy and transport of an intercalary segment for bone graft. This is more laborious, depends on healing at two sites and has transport-specific complications, but it is a powerful strategy in experienced hands, especially when more than 2 cm of lengthening is needed.
Fine-wire fixation advantages: it preserves a compromised soft-tissue envelope, especially when combined with deformity correction.
Pin site care: choose and teach a strategy, because pin site infection near a joint can lead to joint sepsis. (Rockwood)
Infected Nonunion and Bone Defects (Rockwood)
Diagnosis. The gold standard is a positive deep tissue or bone culture. Prior open fracture, previous infection, persistent drainage and constant (not activity-related) pain raise suspicion. Labs usually include CBC, ESR and CRP.
Stratify risk as low, moderate or high, largely by experience.
Low risk: proceed assuming no infection. Intraoperative cultures before antibiotics are reasonable but not mandatory.
Unexpected positive cultures at nonunion repair can be treated with culture-specific antibiotics with retention of internal fixation. Culture-positive but clinically uninfected nonunions with internal fixation and graft have been managed successfully by continuing antibiotics until union.
Moderate suspicion: take deep intraoperative cultures and tissue for histology.
Implants. When existing implants give no or marginal stability, removal is usual. If implants give adequate stability and will continue to do so, retaining or removing is debated. Retention suits cases where union can be expected without grafting, with antibiotic suppression until union, after which removal becomes part of eradication. Removal is favored when infection control is especially problematic or graft is needed. Metal promotes biofilm, and graft is initially avascular and can provide a fertile ground for infection.
Stabilization after removal. External fixation with pins and wires placed outside the zone of infection. In long bones, a reinforced antibiotic cement rod can provide local antibiotic delivery and stability at the same time.
Antibiotic cement nail technique. Mold the cement in a chest tube of appropriate size. Chest tube sizes: 38 Fr (outer 12.1 mm, inner 9.4 mm), 40 Fr (12.7 / 10), 42 Fr (13.3 / 10.5), 44 Fr (14 / 11.3). Inject semi-liquid cement into a tube with an appropriate inner diameter, usually about 1.5 mm smaller than the reamed canal to avoid excessive stress during insertion. Base the length on intraoperative measurements. Insert a thin rod such as an IM reamer guidewire as a metal core before the cement sets. A hook on the end of the nail eases removal. Cut off the tube after the cement hardens and cools, insert through the earlier nail portal, and remove it easily later.
Local antibiotics are particularly useful when debridement leaves dead space. Infected nonunions are often treated in stages. (Rockwood)
Joint Nonunions and Special Situations
Joint nonunions are relatively rare and often oligotrophic, so compression suits them. Consider stiffness, arthrosis and stability. If repair cannot meet the goals, arthroplasty becomes attractive, especially in older patients or with preexisting arthrosis. It is contraindicated with active infection. (Rockwood)
Arthroplasty is relatively suitable for distal femoral and distal humeral nonunions. It is less ideal for proximal femur, proximal humerus and proximal tibia nonunions because of tendon attachments, and rarely suitable for distal tibia because of implant limitations. (Rockwood)
Amputation as definitive treatment is usually driven by soft-tissue and infection problems, comorbidity and patient preference rather than technical inability to unite the bone. Discuss it as a shared decision, with honest discussion of time, energy and functional outcomes. (Rockwood)
Complications
Persistent nonunion or graft resorption, especially with instability or infection. (Rockwood)
Recurrent or persistent infection, hardware biofilm. (Rockwood)
Transport-specific problems: docking-site nonunion, pin site infection, vascular injury and unplanned returns to the OR. (Rockwood)
Soft-tissue envelope failure, which can compromise Masquelet-type reconstruction. (Rockwood)
References
Ricci WM, Ollivere BJ. Principles of nonunion and bone defect treatment. In: Tornetta P III, Ricci WM, Ostrum RF, McKee MD, Ollivere BJ, de Ridder VA, eds. Rockwood and Green's Fractures in Adults. 10th ed. Wolters Kluwer; 2024. Chapter 30 (Turkish edition: Erişkin Kırıkları).