External jig in the placement of distal interlocking screws

Abstract

Background: Placement of distal locking screws is a challenge to many surgeons involved in interlocking nails. Objectives: The aim of this study is to evaluate the accuracy of external jig as a target arm for distal locking screw insertion. Methods: 85 consecutive patients with 90 fractures treated with SIGN interlocking nails were prospectively studied. We report the assessment of the accuracy of insertion of distal locking screws with the use of SIGN external jigs. The patient's demographic data and fracture characteristics were documented. Two distal screws are usually inserted. However, in very difficult cases, one distal screw may be inserted. In all cases there was no access to intra operative radiograph. Results: There were 85 patients and 90 fractures. There were 57 males and 28 females giving a ratio of M:F 2:1. The mean±SD age of the patients was 41.19±16.28 years and the range was 18-85 years. The two bones studied were femur 62.3% and tibia 37.8%. Retrograde (52.2%) was the commonest surgical approach used for femur. The main indication for SIGN interlocking surgery was recent fracture 77.8%. Open reduction 97.8% was the commonest method of reduction used. The mean±SD bone union time was 3.58±0.56 months and range 3-5 months. Distal screw insertion was successful (2 screws) in 93.3% and partial success (1 screw) in 6.7%. At first attempt 96.7% of distal screws were inserted while 3.3% distal screws were inserted at 2nd attempt (2nd visit to theatre). The main complication was screw loosing seen in 3.3%. Conclusion: External jig as a target arm is effective for the placement of distal locking screw.

Keywords: External jig; Target arm; Distal screws; Interlocking nails.