THE XS NAIL – A NEW CONCEPT IN OLECRANON AND ULNA FRACTURE MANAGEMENT

Abstract

Clinical Problem: fractures under tension are common injuries and occur when patients are falling on partial flexed limbs under maximal contraction of the extensor muscles. Typical injuries are patella and olecranon. For these fractures the tension belt osteosyntheses is the mainly used procedure. A high complication rate regarding dislocation, bone healing, pain and functional outcome are reported. This is due to the unstable fixation with the tension belt because of the tendon insertion around the bone fragment witch allow secondary loosening of the tension belt under alternating load. This was found allready 1987 by Brill and Hopf in an experimental study.

Materials and Methods: To improve stabilisation a new device was developed: the XS (4,5mm diameter) and the XXS nail (3,5mm) witch is locked with threaded wires and a set screw allows fracture compression inside the nail independend from the soft tissues around. Fiber Wire cerclage transversal around the threaded wire ends allow the fixation of additional frontal plane fragments or marginal fragments.

Experimental test were performed in a patella sow-bone models and showed superior to tension bel (patella) and Plate fixation/fibula). On the other side the locked nail system allows percutaaneous osteosynthesis of the whole ulna also in shaft, distal fractures and shortening osteotomies.

All clinical cases treated with the XS/XXS nail where recorded prospectively and re-examined after 6–12 months. From may 2000 to march 2002 76 patients with olecranon fractures were evaluated. 85% of the olecranon fracture patients could be re-examined. Most patients where treated immediately or after wound healing without splint.

Results: the experimental results shows in all XS nail group no gap after alternating load of 250 and 500N and a rigidity a little higher than that of the not osteotomised patellae. In the tension belt groups in all tested patellae visible gaps of 1 to 3 mm occurred. There was no difference between the single and double XS nail Osteosynthesis.

71.7% of all patients with olecranon fractures showed a very good result according to the Murphy score. In 2 part fractures the rate was even 94.7%. Only in the group of more part fractures in 5.9% fair results were found. No patient showed a poor result.

The technical possibilities of XS nail osteosynthesis in ulna shaft, distal fractures and shortening osteotomies are presented.

Conclusions: the XS nail is a new device witch allows good anatomical reconstruction and stable fixation with immediate functional therapy in all olecranon and ulna fractures.