PROGNOSTIC FACTORS FOR TREATMENT OF SCAPHOID UNSTABLE NON-UNION BY MEANS OF A TRAPEZIUM-SHAPED GRAFT AND INTERNAL FIXATION

Abstract

Introduction and purpose: The non-reestablishment of normal scaphoid anatomy is related to instability, loss of function and secondary arthritis. The most appropriate treatment for unstable non-unions with scaphoid deformity is the use of a trapezium-shaped bone graft and internal fixation. We present our experience and the results obtained by treatment of this condition.

Materials and methods: We retrospectively studied 35 patients (34 males and 1 female) with unstable scaphoid non-union treated by curettage, trapezium-shaped iliac crest bone graft and internal fixation, with a mean follow-up of 24 months (range: 12–52 months). Mean age of the patients was 29.8 years (range: 18–52) and all had medium to high functionally demanding jobs. In 48% of cases it was the dominant wrist that underwent surgery. In 3 cases there was a previous history of union of scaphoid fracture. To fixate the graft different devices were used: metal cannulated screws (54%), Kirschner wires (22%) and biodegradable screws (22%). Growth factors were used in 5 cases (PRP) and the wrist was immobilized for 8 weeks. We assessed complications, range of movement, union on x-ray, Green and O’Brien’s scale and return to work at the end of follow-up.

Results: Complete union was obtained in 68.6%, partial in 14.3% and incomplete in 17.1%. Four patients (13.8%) required repeat surgery: 2 four-corner arthrodesis, 1 a conventional graft and 1 a vascularized graft. The mean flexion-extension arc was 99.6°; radio-ulnar deviation was 48.6°. According to the modified Green-O’Brien scale, 93% of the patients had excellent to good results. Time off work after surgery was 21 weeks (9-50 weeks). Ninety-five percent of patients returned to their former job. There were no statistically significant differences with reference to the location of the non-union of the fixation used, although cannulated tapered screws had a lower union rate and a greater number of complications. The worst results were associated with previous surgery and signs of radiocarpal degeneration.

Conclusions: Restoration of normal scaphoid morphology by means of a trapezium-shaped graft results in good outcomes and allows an optimum return to work in manual workers. Previous surgery, signs of radiocarpal degeneration and voluminous implants cause the worst functional results. Even if complete union is not seen on x-rays, the functional result may be optimum.