Overview
Malunions and complex deformities can be corrected acutely (osteotomy, realignment and fixation) or gradually (osteotomy followed by gradual realignment with an external fixator or motorized implant). The choice depends on deformity type and location, soft-tissue and neurovascular status, the need to restore length, and the fixation methods available. This guide summarizes the options in Rockwood for choosing a method, and the principles of gradual correction with the Ilizarov frame, the Taylor Spatial Frame (TSF) and intramedullary lengthening nails. (Rockwood)
Indications for Gradual Correction
Angular deformities where neurovascular structures or poor soft tissues lie on the concave side, so acute correction would risk traction injury. Gradual correction lets nerves, vessels and soft tissue adapt. (Rockwood)
Shortening deformities (gradual distraction restores length). Gradual methods can also correct associated angular, translational or rotational deformities. (Rockwood)
Complex combined deformities, which often need gradual correction so that surrounding soft tissue and neurovascular structures can adapt. (Rockwood)
Infection, small periarticular fragments, or situations where concurrent deformity correction and bone healing are desired. (Rockwood)
Choice of Method by Location (Rockwood Table 31-2)
Location | Acute correction | Gradual correction |
|---|---|---|
Diaphysis | Intramedullary nail (preferred where practical), or plates and screws | Intramedullary lengthening nail (for shortening), Ilizarov or TSF |
Metaphysis/epiphysis (periarticular) | Plates and screws, or external fixation for small distal fragments | Ilizarov or TSF |
Diaphyseal malunions. Angulation and translation deformities are easy to identify on plain radiographs, and anatomic axes are used to find the CORAs. Wedge osteotomies at the CORA are usually feasible, so correction does not risk secondary translation. Because the morphology is relatively uniform, diaphyseal deformities suit many fixation methods once corrected, and intramedullary nailing is preferred when practical. (Rockwood)
Periarticular malunions. More difficult to define and treat. Besides length, angulation, rotation and translation, there may be joint malorientation, malreduction of joint surfaces, soft-tissue contractures and compensatory deformities such as fixed joint subluxation. CORAs can be defined using joint orientation angles to construct mechanical axes. Each component must be identified, characterized and prioritized. Acute correction is mostly done with plates and screws or external fixation, and gradual correction with external fixation is especially suited to small periarticular segments. (Rockwood)
Placing the osteotomy at the CORA may be impractical, for example when it would risk soft tissue or neurovascular structures. Then the osteotomy is made proximal or distal to the CORA with a plan that accounts for translation. (Rockwood)
3D planning. Three-dimensional CT reconstructions are valuable for planning malunions with combined deformities. They allow visualization and models to plan osteotomy types and fixation, and patient-specific instrumentation can improve osteotomy accuracy. (Rockwood)
Plate and Screw Fixation
Advantages: rigid fixation; versatility for many locations (such as periarticular deformities); correction under direct vision; reliability after failed or temporary external fixation.
Disadvantages: extensive soft-tissue dissection, limits on early weight bearing and function, and inability to correct significant shortening.
If bone-to-bone contact after reduction is poor, consider other skeletal stabilization methods.
Locking plates act as a fixed-angle device (a single-beam construct), resist bending moments and distribute axial load across all screw–bone interfaces. Plating without compression heals by callus. Because of the inherent stability, contact between plate and bone is unnecessary, so periosteal damage and microvascular insult can be minimal. They cost more and are reserved mainly for cases not suited to conventional plating, and are excellent for osteopenic bone or deformities near the metadiaphyseal junction where screw purchase is poor. (Rockwood)
Intramedullary Nails and Lengthening Nails
Acute correction with an intramedullary nail is preferred for diaphyseal deformities when practical. Note that a nail aligns the bone along its anatomic axis, not the mechanical axis of the limb, which affects planning (for example in the femur). (Rockwood)
Intramedullary lengthening nails can correct shortening deformities. Reported experience with magnetic PRECICE nails (Rockwood):
19 patients with 35 lengthening procedures: complications in 10 patients (53%), including reduced ankle motion, delayed bone healing and device failure.
24 patients: high accuracy and precision for restoring a mean of 35 mm of femoral or tibial length, but 30% needed a return to the OR for device failure, premature consolidation, delayed healing and acquired foot or ankle deformity.
17 patients with femoral lengthening (mean 38 mm): 18% complications.
10 patients with lower-limb shortening (mean 47 mm achieved): 70% had complications such as device failure, compartment syndrome and nonunion.
A matched comparison of a motorized nail with the TSF in femoral shortening deformities found similar results,.
A worked example in the chapter (50-year-old woman with 17 degrees of varus, 19 degrees of anterior angulation and a 40-mm limb length difference after a femur fracture) used percutaneous corticotomy, acute angular correction and a PRECICE nail, with distraction over 5 weeks to final length and consolidation over 3 months. (Rockwood)
Ilizarov Techniques
Advantages (Rockwood): (1) percutaneous and minimally invasive, with minimal soft-tissue dissection; (2) promotes osseous tissue formation; (3) versatile; (4) can be used with acute or chronic infection; (5) stabilizes small intra-articular or periarticular fragments; (6) allows simultaneous deformity correction and enhanced bone healing; (7) permits immediate weight bearing and early joint function; (8) allows the treatment to be advanced or changed by adjusting the frame; (9) tensioned wires resist shear and rotation while permitting a "trampoline effect" of axial loading and unloading.
The Ilizarov fixator can reduce and stabilize nearly any deformity, including complex combined deformities, and restore length in shortening. Several modalities are possible, including monofocal, bifocal and treatment of multiple sites in a single bone at once. Blood flow increases about 10-fold after a corticotomy and lengthening in the tibia. (Rockwood)
Principles of distraction osteogenesis (Rockwood):
Make the corticotomy or osteotomy with a low-energy technique (multiple drill holes with an osteotome under continuous irrigation, or a Gigli saw) to minimize necrosis.
Metaphyseal or metaphyseal–diaphyseal regions have better regenerative potential than diaphyseal regions.
The external fixator construct must be very stable.
Allow a latency period of 7 to 14 days after corticotomy before beginning distraction.
Monitor the progress of regenerate on radiographs and adjust the rate and rhythm of distraction accordingly, since regenerate forms more slowly in some patients. The standard is 1 mm/day in four 0.25-mm increments.
A consolidation phase, usually two to three times as long as the distraction phase, continues in static mode after length is restored, to allow regenerate to mature and hypertrophy.
Complex Combined Deformities
A complete bone deformity can be characterized by one segment's position relative to the other through three angular rotations and three linear displacements (six parameters). Positive rotations follow the right-hand rule, and anterior, right and superior displacements are positive.
Complex deformities often need gradual correction. Correction can be simultaneous (all deformities corrected at the same time) or sequential (for example angulation and rotation before translation). The rate depends on deformity type and size, soft-tissue effects, the patient's health and healing potential, and the balance between premature consolidation and poor regenerate. (Rockwood)
The Taylor Spatial Frame is a hexapod with two rings connected by six struts and uses the six-parameter characterization to correct deformities by adjusting the struts. A distal tibial varus malunion of 21 degrees with the CORA 21 mm above the distal tibial joint line was corrected with a transverse osteotomy and a TSF using differential lengthening. In another case, a patient who could not tolerate the frame was converted to compression and later femoral lengthening with a PRECICE nail. A case of congenital tibial pseudarthrosis with severe oblique-plane deformity and poor soft tissue was treated with nail removal, corticotomy and Ilizarov correction, but regenerate maturation was extremely slow and the frame stayed on for 14 months. (Rockwood)
Postoperative Care
Rehabilitation depends on the construct. Frames need pin care and regular radiographic monitoring of regenerate. Lengthening nails need distraction monitoring and attention to adjacent joint motion. The source chapter text used here does not specify a single protocol. (Rockwood)
Complications
Pin-site problems and, with frames, difficulty tolerating long treatment. (Rockwood)
Poor or delayed regenerate, premature consolidation, nonunion, and device failure (lengthening nails). (Rockwood)
Loss of adjacent joint motion, acquired foot or ankle deformity, and compartment syndrome with lengthening. (Rockwood)
Iatrogenic translation or traction injury when the osteotomy, CORA and correction axis are not matched. (Rockwood)
References
Chapter 31, principles of malunion 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 (Turkish edition: Erişkin Kırıkları).