The efficacy of rotational control designs in promoting torsional stability of hip fracture fixation

Abstract

ObjectivesFractures of the proximal femur are a common clinical problem, and a number of orthopaedic devices are available for the treatment of such fractures. The objective of this study was to assess the rotational stability, a common failure predictor, of three different rotational control design philosophies: a screw, a helical blade and a deployable crucifix.MethodsDevices were compared in terms of the mechanical work (W) required to rotate the implant by 6° in a bone substitute material. The substitute material used was Sawbones polyurethane foam of three different densities (0.08 g/cm3, 0.16 g/cm3 and 0.24 g/cm3). Each torsion test comprised a steady ramp of 1°/minute up to an angular displacement of 10°.ResultsThe deployable crucifix design (X-Bolt), was more torsionally stable, compared to both the dynamic hip screw (DHS, p = 0.008) and helical blade (DHS Blade, p= 0.008) designs in bone substitute material representative of osteoporotic bone (0.16 g/cm3 polyurethane foam). In 0.08 g/cm3 density substrate, the crucifix design (X-Bolt) had a higher resistance to torsion than the screw (DHS, p = 0.008). There were no significant differences (p = 0.101) between the implants in 0.24 g/cm3 density bone substitute.ConclusionsOur findings indicate that the clinical standard proximal fracture fixator design, the screw (DHS), was the least effective at resisting torsional load, and a novel crucifix design (X-Bolt), was the most effective design in resisting torsional load in bone substitute material with density representative of osteoporotic bone. At other densities the torsional stability was also higher for the X-Bolt, although not consistently significant by statistical analysis.Cite this article: J. D. Gosiewski, T. P. Holsgrove, H. S. Gill. The efficacy of rotational control designs in promoting torsional stability of hip fracture fixation. Bone Joint Res 2017;6:270–276. DOI: 10.1302/2046-3758.65.BJR-2017-0287.R1.

Influence of interlocking thread screws to repair simulated adult canine humeral condylar fractures

“…A transcondylar screw that minimized the loss of reduction from rotation would be advantageous and may allow for the type and necessity of anti‐rotational implants to be reconsidered. Human studies focused on evaluating the impact of rotational stability on scaphoid and intertrochanteric fractures showed that the screw design is a contributing factor 35,36 . A secondary fixation was not included in the current construct model, which will affect the clinical relevance of the results; however, the purpose of the study was to evaluate the different screw types in isolation to understand the influence of the new screw thread design.…”

Intracapsular Femoral Neck Fractures—A Surgical Management Algorithm

“…This technique has shown considerable biomechanical advantages over standard cancellous screw placement [ 29 ], and when used for displaced fractures in 207 patients was clinically associated with very low complication rates, such as an AVN rate of only 0.5% [ 31 ]. New implants have been developed primarily for extracapsular hip fractures, such as the X-Bolt (X-Bolt, Dublin, Ireland) using deployable flanges, and show biomechanical improvements over SHS, especially for rotational stability in low density bone [ 32 ]. However, clinical validations of these findings are awaited in intracapsular fractures.…”

Intermediate Dynamic Compression and Decreased Posterior Tilt With Interlocked Pins in Femoral Neck Fixation in Synthetic Bone

“…New fixations have been tried. A self-locking blade , a medial buttress plate (Mir andCollinge, 2015, Giordano et al, 2019), a deployable crucifix (Gosiewski et al, 2017) and a perforated H-beam (Jafarov et al, 2019) have been tested.…”