Purpose: Fractures o the distal radius remain a problem difficult to resolve. A post-operative displacement is observed in about half the cases. The displacement is generally a secondary shortening with mis- or unrecognized metaphyseal comminution. In the United State, autologous bone graft is widely used, which, like bone substitutes also used in France, allows appropriate filling of the metaphyseal comminution which always remains open after pin withdrawal. We present a prospective series of 30 patients with a fracture of the distal radius treated by pin or plate fixation in combination with Norian to fill the substance loss subsequent to metaphyseal comminution.
Material and methods: Thirty patients were treated between November 1998 and March 1999 for fracture of the distal radius with posterior displacement. The inclusion criterion was comminution >
2 according to the Laulan classification. All were treated by osteosynthesis with plate or pin fixation and insertion of Norian. There were 26 women and 4 men. Twenty-two patients had an articular fracture. Plate fixation was used in ten patients and pin fixation in 19.
The fracture involved the dominant side in 21 cases. The fracture was closed in all cases. Norian was injected after osteosynthesis following the recommendations of the manufacturer (impaction of the cavity rims created by the comminution, no motion for 10 min after injection). All patients were reviewed at 1, 3 and 6 months and at last follow-up. The flexion-extension and pronation-supination amplitudes were measured, as was the muscle force.
Results: All patients were reviewed with a minimum follow-up of at least 2 years. Mean age was 65 years (545–82). All fractures had consolidated. There were three defective calluses in patients aged over 80 years with osteoporosis; the clinical outcome was better than the radiological image. Three patients developed reflex dystrophy. Mean amplitudes were: flexion 43.6°, extension 52.3°, pronation 63°, supination 70°. The mean wrist force was 52 kpa. No complications related to Norian were observed. Two biopsies were made and showed, in one case at six months, early signs of osteointegration. The product disappeared progressively after 2 years but not in all patients. The immediate postoperative ulnar variance was unchanged at last follow-up. In seven patients the ulnar variance was modified with impaction of the fracture line but with no effect on pronation-supination.
Discussion: Metaphyseal comminution after fracture of the distal radius is a classical observation. It may be located posteriorly or anteriorly and leads to secondary impaction before or after pin withdrawal. To avoid this problem, and the inversion of the ulnar variance, the bone defect must be filed at the initial surgical procedure. Solutions include bone grafts (autograft, allograft, xenograft) and injection of methylmethacrylate. Bone substitutes can now be used to fill the gap without the theoretical or real risk of bacterial contamination. The first studies in animal models were published in 1995. Kopylov and Jupiter demonstrated the contribution of Norian for fractures of the lower end of the radius to avoid impaction and improve pronation-supination.
Conclusion: Metaphyseal comminution of fractures of the distal radius is a real problem. If the gap is not filled during the initial surgical treatment, impaction with inversion of the ulnar variance can lead to pronation-supination insufficiency. Norian SRS can be used to fill the bone defect producing mechanical results as good as or better than compression cancellous grafts. The produce is resorbed slowly and is easy to use. Its high cost is undoubtedly an inconvenience limiting its use to “young” patients with fractures of the distal radius. After 70 years, the absence of a strong correlation between the radiological and clinical result suggests a less “aggressive” therapeutic approach.
