Distal interlocking screw placement in the femur: free-hand versus electromagnetic assisted technique (sureshot)

Abstract

Objectives: To compare the free-hand (FH) technique of placing interlocking screws to a commercially available electromagnetic (EM) targeting system in terms of operating time, radiation dose, and accuracy of screw placement.

Methods: Between September 2011 and July 2012, we prospectively randomized 100 consecutive femur shaft fractures in 99 patients requiring intramedullary nails to either FH using fluoroscopy (n = 43) or EM targeting (n = 38; Sureshot).

Setting: Single Level 1 University Hospital Trauma Center.

Main outcome measurements: The 2 groups were assessed for distal locking with respect to time, radiation, and accuracy.

Results: Eight-one fractures had data accurately recorded (38 EM/43 FH). The average total operative time was 50 minutes (range, 25-88 minutes; SD, 13.9 minutes) for the FH group and 57 minutes (range, 40-103 minutes; SD, 16.12 minutes) for the EM group. The average time for distal locking was 10 minutes (range, 4-16 minutes; SD, 3.56 minutes) with FH and 11 minutes (range, 6-28 minutes; SD, 10.24 minutes) with EM. Average radiation dose for distal locking was significantly less (P < 0.0001) for EM at 230.54 μGy (range, 51-660 μGy; SD, 0.17 μGy) compared with 690.27 μGy (range, 200-2310 μGy; SD, 0.52 μGy) for FH. There were 2 misplaced drill bits in FH and 3 in EM. This was not statistically significant (P = 0.888).

Conclusions: The electromagnetic targeting device (Sureshot) significantly reduced radiation exposure during placement of distal interlocking screws, without sacrificing operative time, and was equivalent in accuracy when compared with the FH technique.

Level of evidence: Therapeutic level II.