Mechanical Evaluation of a 4-mm Cancellous “Rescue” Screw in Osteoporotic Cortical Bone: A Cadaveric Study

Abstract

There seems to be no advantage in using a cancellous screw over a cortical screw in bicortical fixation in osteoporotic bone. Although the rescue screw provided greater pullout strength than the stripped screw, it is unknown if the purchase it provides is clinically sufficient.

Can High-friction Intraannular Material Increase Screw Pullout Strength in Osteoporotic Bone?

“…In other studies, rescue screws only moderately increase pullout strength [2,14]. Wire augmentation has also been described to increase pullout force [9].…”

“…There are options to repair stripped screws [2,9,14], but each of them has important shortcomings. Because of this, we investigated a HFIA material used to increase pullout strength of stripped screws, assessing augmentation and repair applicability of HFIA in osteoporotic and severely osteoporotic bone models.…”

“…Once a screw is overtightened and the bone thread of the screw hole is stripped, the options to remedy the situation are limited and often unsatisfactory [1,4]. Rescue screws only moderately increase pullout strength [2,14]. Wire augmentation has also been described to increase pullout force, but with uncertain clinical significance [9].…”

Osteoporotic Distal Fibula Fractures in the Elderly: How To Fix Them

“…Osteoporotic bone has more chance of loss of purchase due to relatively weak bone leading to a less stable construct [1,22]. Also, using a larger diameter screw does not solve the problem [23].…”

Biomechanical and Histological Assessment of a Polyethylene Terephthalate Screw Retention Technology in an Ovine Metatarsal Fracture Model

“…To reduce the incidence of screw loosening, various groups have focused on improving screw/plate technologies, [8][9][10][11] among other approaches including bone cements, materials from the operating room and high friction surface coatings. [12][13][14] Many of these efforts are mechanical solutions implemented intraoperatively and carry additional sets of risks such as undue bone-implant pressure, compromised bone stability or increased bone removal.…”