Biomechanical effects of hardware configuration after unionof proximal femoral and shaft fractures. Issue 6 (June 2012)

• Record Type: Journal Article
• Authors: Swinteck, B. J.; Phan, D. L.; Jani, J.; Owen, J. R.; Wayne, J. S.; Mounasamy, V.
• Is Part Of: Bone & joint research. Volume 1:Issue 6(2012)
• Page Start: 104
• Page End: 110
• Publication Date: 2012-06
• Subjects: Dynamic hip screw -- Intramedullary nail -- Femur fracture -- Femoral neck -- Intertrochanteric -- Biomechanical; Musculoskeletal system -- Periodicals; 573.705
• DOI: 10.1302/2046-3758.16.2000067
• Languages: English
• ISSNs: 2046-3758

Abstract

Abstract : Objectives: The use of two implants to manage concomitant ipsilateral femoralshaft and proximal femoral fractures has been indicated, but nostudies address the relationship of dynamic hip screw (DHS) sideplate screws and the intramedullary nail where failure might occurafter union. This study compares different implant configurationsin order to investigate bridging the gap between the distal DHSand tip of the intramedullary nail. Methods: A total of 29 left synthetic femora were tested in three groups:1) gapped short nail (GSN); 2) unicortical short nail (USN), differingfrom GSN by the use of two unicortical bridging screws; and 3) bicorticallong nail (BLN), with two angled bicortical and one unicortical bridgingscrews. With these findings, five matched-pairs of cadaveric femorawere tested in two groups: 1) unicortical long nail (ULN), witha longer nail than USN and three bridging unicortical screws; and2) BLN. Specimens were axially loaded to 22.7 kg (50 lb), and internallyrotated 90°/sec until failure. Results: For synthetic femora, a difference was detected between GSN andBLN in energy to failure (p = 0.04) and torque at failure (p = 0.02), but not between USN and other groups for energy to failure ( vs GSN, p = 0.71; vs BLN, p = 0.19) and torque at failure( vs GSN, p = 0.55; vs BLN, p =0.15). For cadaveric femora, ULN and BLN performed similarly becauseof the improvement provided by the bridging screws. Conclusions: Our study shows that bicortical angled screws in the DHS sideplate are superior to no screws at all in this model and loadingscenario, and suggests that adding unicortical screws to a gappedconstruct is probably beneficial.