Jones Fracture Intramedullary Screw
Intramedullary screws are type of implant designed to sit within the bone being fixated. Benefits of intramedullary fixation include little to no hardware prominence, ease of implantation, and the allowance of micromotion about a fracture site to provide stronger bony healing.
Intramedullary screws can be fully-threaded, partially-threaded or variably-threaded, depending on fixation strategy utilized. They are often cannulated, which allows for insertion over a guidewire. Where strength is of a concern, solid implants can also be used, which provide a much stiffer ultimate fixation construct.
Jones Fracture Intramedullary Screw Fixation
Recently, surgeons have become much more aggressive with treating Jones fractures surgically in the acute setting. They cite high union, return to play and satisfaction rates as reasons to pursue early operative intervention. While some surgeons elect to utilize a plate and screw construct, intramedullary fixation with specialized intramedullary implants provides rigid fixation with minimally hardware prominence, and delivers high union rates. Studies have regularly demonstrated that patients who undergo intramedullary fixation of Jones fractures predictably reach bony union much more quickly than their nonoperative counterparts, and are able to return to sport and work in a much more expedited timeline.
Proximal fifth metatarsal base fractures, or Jones fractures, are a common injury sustained by both athletes and laypeople alike. Often occurring secondary to trauma, Jones fractures occur in a vascular watershed area about the fifth metatarsal base. Owing to the decreased and variable bloodflow in the area, these fractures are prone to nonunion or delayed union.
Traditionally, Jones fractures were treated conservatively, with extended immobilization in a cast, followed by a CAM boot. These treatment modalities however is lengthy, costly, and often leads to high levels of stiffness and diminished athletic performance. It is also associated with high levels of patient dissatisfaction.
The Stryker Asnis JFX™ is an intramedullary screw specifically deisgned for the fixation of Jones fractures. They come in both cannulated and solid-core designs in 4.0mm, 5.0mm and 6.0mm diameters. The screws offer a low profile, smooth head, to eliminated hardware prominence. The large diameters available offer exception stiffness.
The available washers allow for load distribution about the insertion site of the screw to minimize the possibility of screw cut-in. The sighting arm ensures optimal screw location, to ensure anatomic reduction and maximal construct stability. The arm also allows for extracorporeal measurement of screw length to minimize the chance of incorrect or inaccurate measurement.