Cancellous bone graft and Kirschner wire fixation as a treatment for cavitary-type scaphoid nonunions exhibiting DISI

Abstract

Background: Cavitary-type scaphoid non-unions represent one of the most difficult treatment challenges amongst all scaphoid non-unions as they exhibit bone loss, scaphoid shortening, flexion ('humpback') deformity and dorsal intercalated segmental instability (DISI), creating altered carpal mechanics which may proceed to the degenerative changes of scapholunate advanced collapse of the wrist. Our technique and its rationale are presented in the largest-to-date series on cavitary scaphoid non-unions exhibiting DISI.

Methods: Our technique for treatment of these cavitary non-unions is presented through a series of 27 patients.

Results: Union was achieved in (26/27) 96% of cases, with no complications. Carpal mechanics was restored, with an average carpal height index of 1.52 ± 0.06, and an average scapholunate angle was 46 ± 9°. Average follow-up was 2.2 years.

Conclusion: In this subset of patients, we believe this technique is less technically demanding than the use of either cortico-cancellous grafts or various compression screws. Our success equals or betters that of other published techniques, with all patients enjoying a full return to work, even in occupations demanding heavy labour. We believe that scaphoid union, coupled with the often difficult restoration of carpal height and intra-carpal angles, has produced very good functional outcomes in the management of these challenging cases.

Keywords: Carpal height index; Distal radius cancellous autograft; Kirschner wires; Scaphoid non-union; Scapholunate angle.

Fig. 1

Volar approach demonstrating a exposure of fibrous non-union and b decortication of sclerotic, reactive bone at bone ends, creating two bleeding fragments with Kirschner wires used as joysticks

Fig. 2

Radiograph showing insertion of two 1.25 mm Kirschner wires from distal to proximal, highlighting a entry at the thenar muscles and avoidance of the trapezium, and b it is not necessary that the wires be parallel to each other

Fig. 3

a Harvesting autologous dorsal radius bone graft via 1 cm skin incision adjacent to Listers tubercle, and b cancellous bone graft packed around the Kirschner wires into the created cavity

Fig. 4

a Pre-operative radiograph and b CT 3 months after initial injury showing large cavitary defect and dorsal intercalated segment instability; c post-operative radiograph 6 weeks after surgery and d postoperative radiograph 4.5 months after surgery confirming fracture union with restoration of scaphoid height in both groups of patients: (1) previous conservative treatment (2) previous surgery