New fixation approach for transverse metacarpal neck fracture: a biomechanical study

Abstract

BackgroundFifth metacarpal neck fracture, also known as boxer’s fracture, is the most common metacarpal fracture. Percutaneous Kirschner-wire (K-wire) pinning has been shown to produce favorable clinical results. However, the fixation power of K-wires is a major concern. Plate fixation is also a surgical option, but it has the disadvantages of tendon adhesion, requirement of secondary surgery for removal of the implant, and postoperative joint stiffness. A fixation method that causes little soft tissue damage and provides high biomechanical stability is required for patients with fifth metacarpal neck fracture for whom surgical intervention is indicated. The present study proposed fixation using K-wires and a cerclage wire to treat fifth metacarpal neck fracture. The fixation power of this new method was compared with that of K-wires alone and plates.MethodsWe used a saw blade to create transverse metacarpal neck fractures in 16 artificial metacarpal bone specimens, which were then treated with four types of fixation as follows: (1) locking plate with five locking bicortical screws (LP group), (2) regular plate with five bicortical screws (RP group), (3) two K-wires (K group), and (4) two K-wires and a figure-of-eight cerclage wire (KW group). The specimens were tested by using cantilever bending testing on a material testing system. The stiffness of the four fixation types was determined by observing force–displacement curves. Finally, the Kruskal–Wallis test was adopted to process the data, and the Mann–Whitney exact test was performed to conduct paired comparison between the fixation types.ResultsThe fixation strength levels of the four fixation approaches for treating fifth metacarpal neck fracture were ranked in a descending order of LP group (24.6 ± 5.1 N/mm, median ± interquartile range) > RP group (22.2 ± 5.8 N/mm) ≅ KW group (20.1 ± 3.2 N/mm) > K group (16.9 ± 3.0 N/mm).ConclusionThe fixation strength of two K-wires was significantly higher when reinforcement was provided using a figure-of-eight cerclage wire. The strength of the proposed approach is similar to that of a regular plate with five bicortical screws but weaker than that of a locking plate with the same amount of bicortical screws. Cerclage wire-integrated K-wires can be an alternative method that avoids the excessive soft tissue dissection required for plating in open reduction internal fixation for fifth metacarpal neck fracture.

Controlled active exercise after open reduction and internal fixation of hand fractures

“…The surgical approach, as well as the reduction and fixation method, is an important factor to consider in the surgical treatment of hand fractures, as the extent of skin and soft tissue incision and periosteal and peritendinous dissection can be affected by the surgical approach [ 4 , 11 ]. According to the literature on surgical approaches, the internal plate fixation method seems to exhibit superior strength to the external pin fixation method [ 12 ]. However, as open reduction and internal fixation involves a skin incision and peritendinous dissection, care should be taken to minimize tissue damage during the incision and dissection, and some surgeons prefer less invasive surgical methods for this reason.…”

Effect of oblique headless compression screw fixation for metacarpal shaft fracture: a biomechanical in vitro study

“…According to the experimental results, the coefficients of variation for the LP, RP, and K groups were all approximately 30%. These coefficients were higher than those of our previous study, in which artificial bones were employed to investigate the stability of the three fixation methods in metacarpal neck fractures [ 34 ]. This may have been because of differences between the porcine metacarpal specimens.…”

“…Because fresh cadaver metacarpals are difficult to obtain, some scholars have used artificial bones for testing [ 32 – 34 ]. Although the use of artificial bones means that each bone specimen has the identical shape and material properties, artificial bones cannot replicate the trabecular bone structure and anisotropic properties found in actual bones.…”

Effect of a figure-of-eight cerclage wire with two Kirschner wires on fixation strength for transverse metacarpal shaft fractures: an in vitro study with artificial bone

“…From the biomechanical perspective, using only K-wires for fixation is associated with unsatisfactory bending and torque forces [ 11 ]. Nonetheless, numerous studies have reported lower incidences of extensor tendon adhesions and metacarpophalangeal joint stiffness with K-wire fixation than with plate fixation [ 15 , 16 ]. In an effort to retain its strengths and compensate for its disadvantages, the present study developed a new fixation approach involving the placement of two K-wires and figure-of-eight cerclage wire.…”

“…Internal fixation with K-wires is frequently used to treat metacarpal shaft fractures, but their lack of functional stability may result in fixation failure. In our previous study, [ 15 ] achieved satisfactory outcomes in the placement of two K-wires and figure-of-8 cerclage wire for the fixation of metacarpal neck fractures. The objective of the present study was to evaluate the effect of incorporating a figure-of-eight cerclage wire with two K-wires on fixation strength for transverse metacarpal shaft fractures.…”