Fracture Plate Screw Benchmarks
- We utilized PubMed and Google Scholar search engines for this project. Our research indicated that the major orthopedic adverse events related to implant screw and plate include early implant loosening or breakage, screw failures, fixation failure, non-union, infection, plate fracture, distractor malfunction, peri-prosthetic or peri-implant failure.
- Adverse events associated with orthopedic implant screws and plate dysfunction have not been reported widely in the scientific literature.
- Further, most of the scientific literature surrounding plate and screw malfunction has been outdated (more than 10-15 years old). It appears that the current implant systems are better in terms of fit (screw and plate holes) and hence reduced complications.
- Due to the lack of information available on the subject matter, here we presented a general outline of adverse events associated with orthopedic implant screw and plate failures. We would instead recommend a detailed systematic review of adverse events associated with orthopedic screw failures.
Orthopedic Device Failures:
- From a compilation of case-reports, we identified a list of ways in which orthopedic implants (screws and/or plates) may fail.
- 1. The implant may fail by breakage or the bone-implant interface may fail with loosening or fracture.
- 2. Migration of fracture fixation pin
- 3. Plate loosening and screw displacement
- 4. Displaced humeral head suture anchors
- 5. Failed low contact dynamic compression (LCD) plate
- 6. Loosening, Dislocation, Wear and Tear of Prosthetic joints
Clinical Studies related to Orthopedic Screw & Plate Failures/Dysfunction:
- A recent systematic review (James W.A.F. et al., 2020) investigated the surgical performance when inserting non-locking orthopedic screws. The study included 12 studies, of which 260 surgeons inserted a total of 2793 screws.
- The study indicated that nearly 26% of all inserted screws irreparably damaged and stripped screw holes, reducing the construct pullout strength.
- The study reported that in general, the surgeons' awareness of bone stripping was very poor, meaning that screws must be considerably overtightened before a surgeon will typically detect it.
- A variation between individual surgeons' ability to optimally insert screws was observed, with some surgeons stripping more than 90% of samples (screws) and others hardly any.
- A study indicated that using a plate and screw construct for a fixation technique for tibial tuberosity osteotomies (TTO) in 30 patients, was linked with only 1 case of hardware failure (screw or plate dysfunction).
- An in-vitro study (Ching-Kong C. et al., 2020) examined whether half-threaded screw holes in a new titanium locking plate design can substantially decrease the notch effects of the threads and increase the plate fatigue life. The study demonstrated that removing half of the threads from the screw holes markedly increased the fatigue life of the locking plates while preserving the tightness of the screw heads and the bending strength of the locking screws.
- Another study (William H. et al., 2017) investigated the rate of fracture union after locking plate osteosynthesis of distal femoral fractures using the bridge-plating technique. The study demonstrated that the plating constructs with all locking screws used in the diaphysis when bridge-plating distal femur locking plates were 2.9 times more likely to incur a nonunion.
- In a retrospective analysis (Sehan P. et al., 2019), a total of 248 patients underwent anterior cervical discectomy and fusion or anterior cervical corpectomy and fusion with a dynamic plating system and were followed up for more than 2 years were retrospectively examined. The study indicated that screw failures occurred in 23 of 248 cases (92%).
- A controlled laboratory study (Neil D. et al., 2018) done on human cadavers compared the mechanical strength of fracture fixation between an intramedullary screw and plantar-lateral plating. The study indicated that when compared with intramedullary screw fixation, the plantar-lateral plating allowed for greater cycles to failure and peak load before failure, as well as less gap width when applied to cadaver foot specimens with simulated Jones fractures exposed to cantilever bending in a load frame.
- Another study (Eric M. et al., 2020) investigated factors associated with 'Varus Collapse post-ORIF surgery,' which is a common failure mode of proximal humerus fracture (PHF) fixation. The study indicated that 17 of 112 patients suffered from varus collapse, of which, 11 of the 17 patients (64.7%) had screw cross-threading (screw failure).
- A study (Ahmet K. et al., 2015) on cadavers compared the biomechanical fixation strength of cannulated headless variable-pitch screw fixation versus locking plate fixation. The study demonstrated that 'Cannulated headless variable-pitch screw fixation resulted in better failure displacement than locking plate fixation in a cadaveric talus model and could be considered a viable option for talus fracture fixation.'