Radiographic findings related to interlocking nailing: windshield-wiper effect, and locking screw failure

Summary

The purpose of this paper is to describe two uncommon radiographic findings related to the use of interlocking nails (ILNs) fixation. The first one is a radiolucency located around the distal tip of the nail observed in three clinical cases. This radiographic sign was similar to one described in human medicine known as “windshield-wiper effect” and observed around the tip of the screw used for slipped capital femoral epiphysis in children, and also in association with intramedullary nail treatment. In one of our clinical cases, the radiolucency observed four weeks post-surgery completely disappeared two months later, unfortunately a follow-up radiograph was not available in the two other cases. The second complication is related to three screw-bendings observed in the centre of the nail in two clinical cases. In one case both proximal screws appeared to be radiographically bent, and non-union of the fracture was observed five months after surgery. The screws were in fact broken, instead of being bent, which we were able to determine in the second surgery. In the other clinical case, the screw appeared to be radiographically bent, but the fracture had healed. We could not confirm whether the screw was bent or broken because the owner refused to permit removal of the implant. When bone healing complications are detected, bent screws should be checked and suspected of being broken.

Keywords

Interlocking nail - windshield-wiper effect - implant failure

• References

• 1 Dueland RT, Johnson KA, Roe SC, Engen MH, Lesser AS. Interlocking nail treatment of diaphyseal long-bone fractures in dogs. JAVMA 1999; 214: 59-66.
• 2 Duhautois B. L’enclouage verrouille veterinaire: etude clinique retrospective sur 45 cases. Pract Med Chir Anim Comp 1995; 30: 613-630.
• 3 Duhautois B. Use of Veterinary Interlocking Nails for Diaphyseal Fractures in Dogs and Cats: 121 cases. Vet Surg 2003; 32: 8-20.
• 4 Durall I, Diaz MC, Morales I. Interlocking Nail Stabilization of Humeral Fractures. Initial Experiences in Seven Clinical Cases. VCOT 1994; 07: 3-8.
• 5 Durall I, Diaz MC. Early Experience with the Use of an Interlocking Nail for the Repair of Canine Femoral Shaft Fractures. Vet Surg 1996; 25: 397-406.
• 6 Endo K, Nakamura K, Maeda H, Matsushita T. Interlocking Intramedullary Nail Method for the Treatment of Femoral and Tibial Fractures in Cats and Small Dogs. J Vet Med Sci 1998; 60: 119-122.
• 7 Larin A, Eich CS, Parker R, Stubbs P. Repair of diaphyseal femoral fractures in cats using interlocking intramedullary nails: 12 cases (1996-2000). JAVMA 2001; 219: 1098-1104.
• 8 Moses PA, Lewis DD, Lanz OI, Stubbs WP, Cross AR, Smith KR. Intramedullary interlocking nail stabilization of 21 humeral fractures in 19 dogs and one cat. Aust Vet J 2002; 80: 336-43.
• 9 Horstman CL, Beale BS. Long Fracture Repair Using The Interlocking Nail in a Minimally Invasive Surgical Procedure in Cats and Dogs: 65 cases (1994-2001). VCOT 2002; 15: A6.
• 10 Lorinson D, Grosslinger K. Fracture treatment with the interlocking nail system in dogs and cats. In: Proceeding ECVS 2002; 285-86.
• 11 Suber JT, Basinger RR, Keller WG. Two unreported modes of interlocking nail fairlure: breakout and screw bending. VC0T 2002; 15: 228-32.
• 12 Maletis GB, Basset GS. Windshield-Wiper Loosening: A Complication of In Situ Screw Fixation of Slipped Capital Femoral Epiphysis. J Pediatr Orthop 1993; 13: 607-09.
• 13 Ebraheim NA, Sabry FF, Elgafy H. Intramedullary fibular allograft and nail for treatment of femoral shaft nonunion. Am J Orthop 2002; 31: 270-72.
• 14 Durall I, Diaz-Bertrana MC. Use of Interlocking Nails in Small Dogs and Cats. 1998. ACVS Proceedings 33: 449-51.
• 15 Durall I, Diaz MC, Morales I. An Experimental Study of Compression of Femoral Fractures by an Interlocking Intramedullary Pin. VCOT 1993; 06: 93-99.
• 16 Rosen H. Radiographic interpretation: fracture healing. In: Manual of Internal Fixation in Small Animals. 1th Ed.. Brinker WD, Hohn RB, Prieur WD. (eds). Berlin: Springer Verlag; 1984: 116-24.
• 17 Morrissy RT, Busch MT. Letter to editor. J Pediatr Orthop 1994; 14: 549-550.
• 18 Basset GS. Letter to editor. J Pediatr Orthop 1994; 14: 549-550.
• 19 Langley-Hobbs SJ, Friend E. Interlocking nail repair of a fractured femur in a turkey. Vet Rec 2002; 150: 247-48.
• 20 Zickel RE. An intramedullary fixation device for the proximal part of the femur. Nine years experience. J Bone Joint Surg 1976; 58-A: 866-72.
• 21 Tencer AF, Johnson KD, Johnston DWC, Gill K. A Biomechanical Comparison of Various Methods of Stabilization of Subtrochanteric Fractures of the Femur. J Orthop Res 1984; 02: 297-305.
• 22 McDermott AGP, Rusell L, Gross AE, Ready J. Biomechanical testing of the locking nail principle. 33^rd Ann Meet Orth Res Soc 1987; 388.
• 23 Aper RL, Johnson KA, Litsky AS, Roe SC. Fatigue study of 2.7 mm cortical screw used in a 6 mm diameter interlocking nail. Vet Surg 2002; 31: 475.
• 24 Muir P, Johnson KA, Markel MD. Area Moment of Inertia for Comparison of Implant Cross-Sectional Geometry and Bending Stiffness. VCOT 1995; 08: 146-52.
• 25 Rusell TA, Taylor JC, LaVelle DG. Mechanical characterization of femoral interlocking intramedullary nailing system. J Orthop Trauma 1991; 05: 332-40.
• 26 Wu C-C, Shih C-H. Biomechanical analysis of the mechanism of interlocking nail failure. Arch Orthop Trauma Surg 1992; 111: 268-72.
• 27 Dueland RT, Vanderby Jr, McCabe RP. Fatigue Study of Six and Eight mm Diameter Interlocking Nails with Screw Holes of Variable Size and Number. VCOT 1997; 10: 194-99.