A Simple Technique to Prevent Screw Stripping During Hardware Removal Using Bone Wax

Hardware removal is a common procedure in orthopedics, but it can be challenging and time-consuming. Difficulties in screw removal may arise due to bone growth or cement covering the screw heads, leading to screw damage, and increased surgical time. In this article, we describe a simple and inexpensive technique utilizing bone wax to protect screw heads from bone growth or cement, facilitating future implant removal. The application of bone wax over screw heads acts as a barrier, preventing bone growth or cement from engaging with the screw heads.

New technique for removing bone covering miniplates and screws

Miniplate osteosynthesis has revolutionised the treatment of open reduction and internal fixation in craniomaxillofacial procedures. However, when complications arise necessitating the removal of previously placed miniplates, bony overgrowth may be present and must be eliminated before removal of the hardware is possible. Osteogenesis over the screws prevents proper engagement of the screwdriver with the screw drives. If bone remains embedded in the screw drive during attempted removal of the screw, the contact interference increases the risk of the screwdriver slipping and the screw drive being stripped. There remains a lack of adequate techniques to clear bony overgrowth from miniplates and screws to allow for easy removal, as conventional methods are ineffective, time-consuming, and may damage the screw drives. Herein, we describe a new laser-assisted miniplate removal technique to eliminate bone that has grown over miniplates and screws before the miniplate is removed. This technique is efficient, safe, and simple and, compared with conventional methods, may decrease the complications associated with the removal of miniplates and screws.

Influence of the number and position of stripped screws on plate-screw construct biomechanical properties

INTRODUCTION

Screw stripping is a common situation in fracture fixation, particularly in osteopenic bone treatment. Surgeons' perception of screw stripping is relatively poor and the real number of loose screws in every plate-screw construct is unknown. The biomechanical and clinical implications of the different possible screw-stripping situations are also unidentified. In this study, construct stiffness in different scenarios of stripped screws is investigated.

METHOD

A bone surrogate comminuted osteoporotic fracture was fixed with four screws in both sides of the fracture gap in 75 specimens. In four groups, one or two screws closest or distal to the gap were over-tightened and left in place in one part of the construct and the remaining screws were tightened with 0.3N m torque (four groups). In the fifth group (control), all the screws were tightened with 0.3N m torque. Construct stiffness was tested in terms of compression, bending, and torsion for 1000 cycles.

RESULTS

When one or two screws closest to the gap were stripped, stiffness only decreased by, respectively, 5.7% or 7.6% under compression and 4.7% or 6.7% under bending; however, stiffness in torsion was 15.1% or 32%, respectively, lower than the initial stiffness. When a screw distal to the gap was stripped, the stiffness decreased by 28% under bending and 10% under compression; no change was noted under torsion. When two screws distal to the gap were stripped, the stiffness decreased by 11% in compression, collapsed under bending, and decreased by 8% under torsion.

CONCLUSIONS

Position and number of stripped screws affect the biomechanical properties of a construct in different ways, depending on the acting forces.

Salvaging the pullout strength of stripped screws in osteoporotic bone

Our goal was to determine whether the pullout strength of stripped screw holes in osteoporotic bone could be increased with readily available materials from the operating room. We inserted 3.5-mm stainless steel nonlocking self-tapping cortical screws bicortically into 5 osteoporotic humeri. Each screw was first stripped by rotating it 1 full turn past maximum torque. In the control group, the screw was pulled out using an MTS machine (858; MTS Inc, Eden Prairie, Minnesota). In the treatment groups, the screw was removed, the hole was augmented with 1 of the 3 materials (stainless steel wire, polysorb suture, or polyethylene terephthalate glycol plastic sheet), and the screws were replaced and then pulled out. The effect of material on pullout strength was checked for significance (P < .05) using a general linearized latent and mixed model (Stata10; StataCorp, College Station, Texas). The mean (95% confidence interval) pullout strength for the unaugmented hole was 138 N (range 88-189), whereas the holes augmented with plastic, suture, or wire had mean pullout strengths of 255 N (range 177-333), 228 N (range 149-308), and 396 N (range 244-548), respectively. Although wire augmentation resulted in pullout strength that was significantly greater than that of the unaugmented screw, it was still below that of the intact construct.