Vascularized growth plate transfer for distal radius reconstruction

Abstract

Distal radius reconstruction in children should meet two requests: restoration of some joint function and preservation of the physiologic growth of the segment. None of the conventional options is likely to successfully achieve both goals. Conversely, a vascularized transfer of the proximal fibula including the growth plate provides enough bone stock for diaphyseal reconstruction, an articular surface for joint function, and the potential for longitudinal growth. From 1992 to 2006, eight children ranging in age between 2 and 10 years underwent a vascularized transfer of the proximal fibula for distal radius reconstruction after bone sarcoma resection. The follow-up ranges were between 1 year and 15 years. All the grafts were harvested based on the anterior tibial artery. Seven cases with a follow-up longer than 2 years have been evaluated both clinically and radiographically. All the grafts survived and had a satisfactory growth after the transplant. The functional outcome has been satisfactory, and the range of motion of the reconstructed wrist has been nearly normal in all cases but one. Proximal fibular epiphyseal transfer was an effective procedure for distal radius reconstruction in children who underwent tumor resection. Refinements in the operative technique have increased the reliability of this reconstructive option, which might be safely used also in congenital and posttraumatic disorders.

Keywords: Epiphyseal transfer; bone reconstruction; distal radius reconstruction; pediatric microsurgery.

Figure 1

According to the amount of the resection, three possible options may be chosen for bone fixation, as demonstrated in the following radiographs. (A) When only the distal part of the radius is resected, a stable osteosynthesis may be achieved with compression plate. (B) When the whole radius is resected, a surgical radioulnar synostosis is recommended. (C) When the distal ulna is also involved in the resection, a one-bone forearm is the only possible alternative.

Figure 2

As demonstrated on the radiograph, the assessment of the distance between the tip of the epiphysis and the metal plate is a simple and reliable method to evaluate the growth.

Figure 3

As observed on the radiographs, in this patient the longitudinal growth of the transferred fibula was 3.3 cm in a 4-year period with a growth rate per year of 0.8 cm.

Figure 4

The functional outcome has been excellent in all cases where the ulna and the proximal part of the radius have been spared during tumor resection. At 9-year follow-up, this patient shows a nearly normal range of motion at the wrist joint.

Figure 5

Morphologic remodeling of the transferred epiphysis has been observed in all cases (panel A, CT scan; panel B, three-dimensional CT reconstruction). Under the influence of loading, the articular surface became concave, thus improving the articular congruity with the first carpal row.

Figure 6

Although a progressive divergence of the neoradius and ulna might be expected as long as longitudinal growth occurs, the plasticity of the immature bone, governed by the biomechanical input, allowed for longitudinal remodeling. A progressive bowing ulnarward of the neoradius prevented an excessive opening of the space between the two bones and following possible functional impairment. Instead of diverging during growth, the slight ulnarward bowing of the neoradius provided a more stable joint closing the space between the radius and ulna.

Figure 7

(A) In case of resection of both radius and ulna, (B) the wrist joint is not stable enough to prevent a radial deviation, which in this patient gradually occurred at medium term as seen on the radiograph. This patient is a candidate for radiolunate arthrodesis.