Fifth Metatarsal Tuberosity Fracture Fixation: A Biomechanical Study

Abstract

This study tested the hypothesis that fixation of a fifth metatarsal tuberosity fracture with a lag screw that engages the intact medial cortex is biomechanically stronger than fixation with a long intramedullary screw (control). The right and left feet from 10 male cadavers were alternately assigned to the two fixation groups. After fracture reduction and fixation, each specimen was potted in acrylic cement and tested on a servohydraulic testing machine. The repairs were then distracted until failure by placing the peroneus brevis tendon under tension at a rate of 1 mm/s. The lag screw technique resulted in a significantly greater mean (+/- SD) load to failure (150 +/- 90 N) than did intramedullary screw fixation (70 +/- 60 N) (p < .05) and may offer a useful method of internal fixation of fifth metatarsal tuberosity fractures when surgical stabilization is indicated.

Intramedullary screw fixation in proximal fifth-metatarsal fractures in sports: clinical and biomechanical analysis

“…Several studies analyzed stress peaks and force directions in the Wfth metatarsal [4,[21][22][23][24][25]. Arangio et al [21] found that maximal stress loading in an oblique direction is consistent with proximal diaphyseal stress fractures.…”

Peroneus brevis as source of instability in Jones fracture fixation

“…An early mobilization and return to competition is desired, but without compromising the stability of fracture fixation. Impaired healing response can be attributed to a compromised blood supply at the metadiaphyseal region [9,10], but mechanical instability may also play a detrimental role in Jones fracture healing [11][12][13]. It was postulated that early return to unrestricted sports activities might contribute to Level of evidence: Level II, controlled laboratory study Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00264-020-04581-2) contains supplementary material, which is available to authorized users.…”

Accurate determination of screw position in treating fifth metatarsal base fractures to shorten radiation exposure time

“…The pathological mechanism, diagnosis and treatment of fifth metatarsal base fractures are controversial. (6) Generally, the articular surfaces of the proximal fourth and fifth metatarsal bases have been used to distinguish between extra-articular (Type I) and intra-articular (Type II) fifth metatarsal fractures. (14) In the present study, the metatarsal axis was determined according to the method described by Shima et al, in which the line connecting the midpoint of the proximal articular surface and centre of the distal articular surface provided the most accurate metatarsal axis.…”

“…Thus, almost all operations are performed using a C-arm X-ray image intensifier to ensure correct screw positioning. (6,7) However, this exposes both the medical staff and patient to radiation. A recent survey revealed that more than 75% of medical staff underestimate the potential risk of exposure to radiation.…”

“…(5) The use of lag screws provides an additional mechanical advantage, as they are stronger than single screws. (6) Due to the very small fragments associated with proximal fractures, it is rare to have more than one screw placement opportunity. Thus, almost all operations are performed using a C-arm X-ray image intensifier to ensure correct screw positioning.…”