Jone's Fracture

Jones Fracture is a fracture of the proximal fifth metatarsal bone. Sir Robert Jones (British surgeon) sustained an acute fracture at the base of the fifth metatarsal bone while dancing and the fracture was then named after him. The Jones fracture occurs at the metaphyseal/diaphyseal junction and it extends into the intermetatarsal joint proximal to the metatarsocuboid joint. The joints are connected to the base of the fifth metatarsal bone. One joint articulates with the cuboid bone (metatarsocuboid) and the second joint (intermetatarsal) articulates with the fourth metatarsal. For the Jones fracture to be called “Jones Fracture,” the fracture must enter the intermetatarsal joint (fracture must be distal to the metatarsocuboid joint and must enter the intermetatarsal joint). The Jones fracture occurs about 1 ½ cm distal to the tuberosity of the fifth metatarsal bone. The metatarsal bone is divide into the head, neck, shaft, and the tuberosity. Jones fractures of the proximal fifth metatarsal occurs in the watershed area within 1.5 cm of the tuberosity. The area where the Jones fracture occurs is an area of limited blood supply. There are multiple metaphyseal arteries in the tuberosity. There is a nutrient artery with intramedullary branches provides retrograde blood flow to the proximal fifth metatarsal. Fracture distal to the tuberosity will disrupt the nutrient artery supply resulting in relative avascularity.

The Peronius Tertius tendon is inserted into the dorsal metaphysis of the fifth metatarsal bone . The Peroneus Brevis tendon is inserted into the tuberosity of the fifth metatarsal bone. The plantar fascia is connected of the fifth metatarsal bone. When a Jones fracture occurs, the tendons will pull the fracture apart and prevent healing. This fracture could be mistaken for sprain, because a sprain is common on this side of the foot. There are three types of fractures at the proximal fifth metatarsal bone.

Fracture in zone I which is the tubersority avulsion fracture. Fracture in zone II which is the two Jones fracture. Laslty, fracture in zone III which is the stress fracture.  In zone I avulsion fractures (psuedo Jones fracture). The Peroneus Brevis insertion site and one treats that fracture conservatively. If one takes fracture in zone II, that is the two Jones fracture. They are usually acute fractures that occur at the metaphyseal-diaphyseal junction and involve  the fourth and fifth metatarsal articulation. Zone III stress fractures are chronic fractures that occur distal to the foruth and fifth metatarsal articulation and may be associated with cavovarus foot deformity. In children, it is important not to make the wrong diagnosis of a fracture of the proximal fifth metatarsal base while looking at a normal growth plate. The growth plate is usually present between the ages of 9-14 years of age and it is parallel and lateral to the metatarsal.

During radiology, x-rays will show the fracture and its location. An acute jones fracture will have sharp margins with no intramedullary sclerosis. A stress fracure will have a wide fracture line with medullary sclerosis. Treatment of Jones fracture, if the fracture is nondisplaced one should use a boot or a cast. A person should be nonweight baring for 6-8 weeks and 75% will heal. In athletes or if the fracture is displaced, a screw fixation of the fracture should be performed. This technique is a very popular one. In the lateral view, the canal appears to be straight and narrow. In the AP view, the fifth metatarsal appears to be curved (lateral bow). Lateral bow of the fifth metatarsal may cause complications during surgery. There is vulnerability at the midshaft for perforation of the medial cortex. The canal us narrower in the dorsal view plantar dimension, which is narrow in the lateral view. The point of entry for the wire or the screw is not centered. The fifth metatarsocuboid joint blocks the proximal canal projection and this situation can cause complications. Each paitent’s metatarsal  should be evlauated indivdually for proper screw selection. For surgery and screw placement, drill parallel with the shaft in the lateral plane and avoid the plantar direction and avoid the Sural nerve. One will probably need to use a 4.5 mm cancellous screw. The appropriate length of the screw that should be used is usually around 40-50 mm. The diameter of the screw depends on the width of the canal. Smaller screw fixation is unstable and a larger screw may displace the fracture. The screw threads must cross the fracture site. Failure of the procedure is attributed to poor blood supply or return of the athlete to activity before complete radiographic union.