The role of decortication in the treatment of nonunions

10.1055/b-0034-86365

The role of decortication in the treatment of nonunions

René K Marti

Introduction

Decortication and bone grafting is the most effective biological intervention to stimulate union of hypertrophic nonunions but also of atrophic nonunions. A hypertrophic bridging callus formation can be expected.

A bone graft by itself, simply lying around a sclerotic cortical defect, will not be incorporated and structured. Decorticated cortical fragments—still attached to periosteum or with soft-tissue attachments—together with a cancellous bone graft will form a real biological package around the nonunion, stimulating rapid vascularization.

The problem is that many surgeons do not perform this part of the nonunion treatment as it should be done. This experience resulted from the large number of nonunion patients referred to the author′s institution. They were sent back to the primary surgeon with a specific treatment concept. If the suggested intervention failed again, decortication had either been performed insufficiently or not at all.

Decortication starts with the exposure of the nonunion. Any stripping of the periosteum, muscle or other soft-tissue attachments should be avoided. Sharp osteotomes have to be used to expose the nonunion, creating thin vascularized cortical bone fragments. The procedure can be compared to the peeling of the first layer of an onion.

It is incorrect to expose the nonunion with a periosteal elevator or even with electrocoagulation followed by chiseling of cortical fragments, which are no longer vascularized. These bone chips act as sequesters, especially in presence of an infection.

Another common error is the decortication of thick bone fragments, in which only the exterior layer remains vascularized, providing insufficient blood supply to the interposed cancellous bone graft. The same vascular barrier is created when homologous cancellous bone is used.

Decortication is an art that has to be understood and learned by experience (see also chapter 1.1 “Evolution of treatment of nonunions“, Fig 1.1-16).

Musculo-periosteo-osteal decortication. a In areas of nonunion, the vascularization of the external cortex and callus depends largely on periosteal blood supply. **b–c** Decortication with a sharp osteotome or chisel creates vascular periosteal bone fragments (1) which must remain attached to the periosteum. d The area of decortication should extend 2–4 cm into normal bone distal and proximal to the area to be bridged. The cancellous autograft (2) should be placed within the area of decortication.

Principle of decortication: hypertrophic nonunion after intramedullary nailing. Thin cortical fragments are chiseled off the hypertrophic, well-vascularized callus, and pure cancellous bone is interposed possibly together with thin layers of the hypertrophic callus.

A proposed supramalleolar valgization osteotomy is performed at the tibial shaft level—a hypertrophic nonunion is the consequence.

Case examples

The following case examples demonstrate the effectiveness of decortication alone or combined with bone grafting.

Case 1: Stable fixation of a hypertrophic nonunion without decortication

A proposed supramalleolar valgization osteotomy has been performed at the tibial shaft level—a hypertrophic nonunion is the consequence (Fig 1.4.1-3).

Advised correction: decortication and stable wave plate fixation.

Stable, rigid fixation is performed, but decortication is omitted (Fig 1.4.1-4). Therefore, a bridging callus will not be formed, much rather a long period of gap healing is the consequence, comparable to a rigid fracture fixation with a gap. Full consolidation finally occurred after 12 months.

Decortication of the hypertrophic nonunion on the lateral side as well as under the slightly waved plate medially would have led to consolidation within 8–10 weeks.