5th Metatarsal

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Avulsion Fx
Foot Anatomy
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Jones Fracture
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5th Metatarsal Fractures & Treatment

Fractures of the fifth metatarsal (shaft of the small toe) are common in athletics. The method of injury is similar to that of an ankle sprain. The athlete will invert and dorsiflex the foot, this can result in a twisting force about the base of the 5th metatarsal. Do not discount pain at the base of the foot when evaluating an ankle sprain to avoid missing a fracture of the 5th.

There are four basic types of fractures that can occur to the 5th metatarsal.

  • Avulsion fracture of the tuberosity of the 5th.

  • Jones Fracture.

  • Shaft fracture of 5th metatarsal.

  • Stress Fracture

All of these fractures need to be treated appropriately to avoid long term problems.

The diagnosis of a Jones Fracture has been used to describe several injuries. The true Jones Fracture is a transverse fracture at the junction of the diaphysis and metaphysis of the fifth metatarsal. This is the blue highlighted area in the diagram.

This is potentially the worst fracture of the 5th metatarsal. The area in question has a very limited blood supply. Due to this healing is very slow and many times healing may not occur. The x-ray below the diagram shows a Jones Fracture (red arrow).

In an athlete, surgical fixation may be the first treatment option. Non-surgical treatment can consist of six to 16 weeks in a cast. Since this area does not heal well, many athletes treated without surgery, experience recurrent fractures of this bone.

During surgery, the physician will drill a hole in the bone from the tuberosity (bump on the outside of the base of the 5th metatarsal) into the shaft of the bone. The surgeon then inserts a screw into the hole to hold the two fragments of the bone together. The fluoroscopic picture shows the bone after the screw has been inserted.

The athlete is then placed in a cast, non-weight bearing for four to 6 weeks. During this time, the athlete is performing light range of motion and strength training exercises. After weight bearing is allowed, the athlete can begin more difficult strength training, proprioception (balance and coordination) exercises, and finally sport specific drills.

Avulsion fractures happen in the red area shown in this picture. This injury happens, most often, in a skeletally immature athlete. The peroneus brevis tendon attaches near the growth plate at the base of the 5th metatarsal. The mechanism of injury is similar to an ankle sprain. The ankle “rolls over,” the peroneal muscles contract to prevent the sprain, and the growth plate is fractured. The picture above shows an avulsion fracture of the 5th metatarsal.

Treatment for this injury is usually conservative. The young athlete will be casted for four to six weeks. The athlete then begins rehabilitation exercises for range of motion, strength, and proprioception. These injuries heal with little or no long term disabilities, return to full athletic competition is normal.

Fractures to the shaft of the 5th metatarsal are the next group of injuries. Fractures can happen along the entire shaft of the bone. Treatment depends upon the location of the fracture.

Treatment can range from conservative casting and non-weight bearing to internal fixation with a screw. This x-ray shows a shaft fracture with internal fixation.

Chronic pain on the outside of the foot following an acute injury can be indicative of a fracture that was missed on the initial evaluation. If the athlete continues to have low grade pain on the outside of the foot 3 to 6 weeks after the initial injury, repeat x-rays should be taken to rule out a stress fracture.

This x-ray shows a healing stress fracture (arrow). The white area surrounding the line at the arrow is indicative of an area of healing. This fracture may have been missed on the initial x-ray due to its small size. The athlete may have attempted return to normal activities but was limited by chronic low grade pain in the outside of the foot.

Again, a fracture in this area, may or may not heal. As the x-ray shows, the bone near the fracture site is changing this is indicative of the fracture failing to heal. A recurrent stress fracture may respond to internal fixation with better healing results than conservative treatment (casting) only.

Pain in the outside of the foot, especially after an ankle sprain needs to be investigated. The differential evaluation should include the fifth metatarsal. Skeletally immature athletes should be evaluated by an orthopaedic surgeon to rule out fractures, especially avulsion fractures of the ankle and to the base of the fifth metatarsal Chronic pain should also be investigated to rule out a chronic stress fracture.

 

 

 

©2000 - 2009 David Edell

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Last Update for AthleticAdvisor.com: 10/24/2009 12:09:35 AM