Reconstruction of malunited diaphyseal fractures of the forearm

Abstract

The forearm is a complex anatomical and functional unit with unique osseous, soft tissue and articular relationships. Disruption of these important relations can have a significant impact, leading to pain, instability of the radio-ulnar articulation and reduced range of motion. The gold standard for treating forearm fractures in adults remains anatomic reduction, stable plate fixation and preservation of the surrounding blood supply. Failure to achieve these goals may lead to malunion, requiring reconstructive surgery, which can be technically challenging. In this review, we discuss the essential aspects of anatomy and pathomechanics, clinical and radiological assessment and the state of the art in pre-operative planning and deformity correction surgery.

Keywords: Correction; Deformity; Diaphyseal; Diaphysis; Forearm; Fracture; Malunion; Malunited; Osteotomy; Reconstruction.

Fig. 1

Measurement of the magnitude and location of the maximal radial bow. Using an AP forearm radiograph in neutral, including the wrist and elbow, a line is drawn from the midpoint of the bicipital tuberosity to the ulnar-most aspect of the distal radius to form a baseline (y, mm). A perpendicular line is drawn from the baseline to the point of maximal radial bow (a, mm) and represents the magnitude. The distance from the bicipital tuberosity to the intersection of this perpendicular line (x, mm) represents the location as a percentage proportion of the baseline (x/y × 100). (Adapted from Schemitsch and Richards [48]; permission acquired)

Fig. 2

A step-by-step guide to deformity correction. (1) Superimpose the contours of the forearm bone in malunited position with the anatomical position. (2) Define the maximum point of deformity and determine the osteotomy site. (3) Measure the angles of correction required, calculating α, β and δ angles. (4) Check the angles against standardised reference tables. (5) Draw the osteotomy wedge and measure the wedge height. (6) Prepare the plate and measure the plate offset..(7) Close the osteotomy and stabilise

Fig. 3

The concept of overlay drafting. The contours of the major fracture fragments of the malunited forearm are superimposed over the outline of the “normal” contralateral side, using tracing paper, cutouts or electronic tablet devices linked to a computer. (Images courtesy of D. Fernandez [25]; permission acquired)

Fig. 4

Malunion involving radio-dorsal and ulnar-volar angular deformity of the middle third of the radius. a Orthogonal radiographs are used to assess the orientation and value of the maximal angular deformity, and b projections are measured in the frontal (δx) and sagittal planes (δy). c Pre-operative planning starts with superimposition of radiographs from both sides allowing angular deformity assessment in both planes. d Established tables [37] factor in δx and δy to assess the true angle of deformity (δ) and orientation of deformity in space (β). e δ defines the angle required for a closing wedge osteotomy or structural bone graft for open wedge osteotomy depending on correction required. f Correction is performed in the plane of maximum deformity, i.e. β in relation to the frontal plane. Intra-operatively, two Kirschner wires (K-wire) (plain line) are placed in the frontal plane using the distal radius as a landmark. The osteotomy level also is marked with a K-wire. Finally, the plane of correction is marked with two K-wires (dotted line) inserted with a β angle with respect to K-wires in the frontal plane. The second of these wires is inserted with a δ angle in relation to the first. Both K-wires should be parallel after osteotomy, i.e. δ = 0 and β angle stays the same. (Adapted from L. Nagy, L. Jankauskas and C.E. Dumont [36]; permission acquired)

Fig. 5

Oblique corrective osteotomy for a malunited diaphyseal fracture of the forearm. a Comparison radiographs—AP and lateral views of the left forearm malunion and the normal contralateral side. b Clinical demonstration of pre-operative rotational profile. c Operative technique with exposure of the malunion site, plate contouring, oblique osteotomy and stabilisation of the osteotomy site. d Post-operative radiographs—AP and lateral views and post-operative range of motion

Fig. 6

Single-cut corrective osteotomy for a malunited diaphyseal fracture of the forearm. a Pre-operative clinical image and radiograph of a complex malunion of the forearm. b CT-guided development of a plastic model of deformity to aid pre-operative surgical planning and simulation of bone wedge excision in the true plane of deformity. c Operative technique with exposure of the malunion site, single-cut osteotomy, temporary stabilisation with external fixator and definitive plate stabilisation of the osteotomy site. d Post-operative radiographs—AP and lateral views