Augmented screwdrivers reduce bone stripping rates and optimize tightness when inserting non-locking screws (TightRight)

 
J Fletcher, V Neumann, B Gueorguiev

Background

Non-locking screws remain the most commonly used orthopedic implants, however they are often poorly inserted. Exceeding the stripping torque for a screw hole reduces pullout strength by more than 80%.

 

 

Goal

To quantify stripping rates and screw tightness for orthopedic trauma surgeons and assess how these change when using a screwdriver that indicates when optimum tightness is reached.

 

Results

At the AO Davos Courses, orthopedic trauma surgeons tightened 20 screws in two phases: (1) screws tightened to the surgeon’s perception of optimum tightness, and (2) using an augmented screwdriver indicating when a predetermined optimum tightness – defined as 70% of the maximum stripping torque – was reached. Within each phase, 10 partially inserted   3.5 mm non-locking cortical screws were tightened through a 3.5 mm plate into 4 mm thick artificial bone analogue. The stopping torque for each screw was recorded and compared to the stripping torque; if the stopping torque greatly exceeded the stripping torque, tightness values higher than 100% were possible.

With a normal screwdriver, stripping rates were high, though varied greatly amongst surgeons. Using an augmented screwdriver greatly improved insertion, with optimum tightness being achieved alongside with a significantly reduced rate of bone stripping.


Fund:

Royal College of Surgeons, UK, GBP 5'000, Period: 2019.


  • Presentation

    Fletcher J, Neumann V, Silva J, Mys K, Panagiotopoulou V, Verschueren A, Gueorguiev B, Richards RG, Whitehouse M, Preatoni E, Gill H. TightRight: augmenting screwdrivers to reduce bone stripping rates and optimise tightness when used inserting non-locking screws. 2019 BORS BRS (oral)

    Fletcher J, Neumann V, Wenzel L, Gueorguiev B, Richards RG, Whitehouse M, Gill H, Preatoni E. Assessing screw tightness and stripping rates achieved by orthopaedic surgeons and researchers. 2019 EFORT (poster)

    Fletcher J, Neumann V, Silva J, Mys K, Panagiotopoulou V, Gueorguiev B, Richards RG, Whitehouse M, Preatoni E, Gill H. Augmented screwdrivers greatly reduce bone stripping rates and optimise tightness when used to insert non-locking screws. 2019 BOA (poster)

    Fletcher J, Neumann V, Wenzel L, Gueorguiev B, Richards RG, Whitehouse M, Gill H, Preatoni E. Assessing screw tightness and stripping rates achieved by orthopaedic surgeons and researchers. 2019 ICORS (poster)

    Britisch Orthopaedic Research Society (BORS) and Bone Research Society (BRS), Cardiff, Wales, 4-6 September (2019), second prize for best podium presentation. London Shoulder Meeting (LSM), London, UK, 17 May (2019) (poster)

  • Partner

    Gill H (Prof), University of Bath, Bath, UK

    Preatoni E (MD), University of Bath, Bath, UK

    Whitehouse M, University of Bristol, Bristol, UK

    Verschueren A (MD), University of Bath, Bath, UK

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