Metatarsal fractures represent common injuries of the forefoot. The fifth metatarsal is the most common metatarsal to be fractured. Most commonly, it is injured during inversion type injuries (ankle sprains). Fractures to the fifth metatarsal may also occur from direct or crushing types of injuries, as well as from stress or fatigue fractures.
In general, fifth metatarsal fractures may be grouped into three basic types. The first is known as an avulsion fracture. This type of fracture is common with ankle sprains or other inversion type foot injuries. The fracture occurs at the base, or styloid process of the fifth metatarsal. It is caused by the traumatic pulling of the peroneal brevis tendon (or a ligament) from the end of the metatarsal. The fracture is always transverse in nature and usually results in very little displacement or malalignment. The second type of fracture is often referred to as aJones fracture. The fracture is also transverse in nature. However, it occurs further down on the metatarsal, in a region known as the metaphyseal-diaphyseal junction. This injury is usually caused by stress placed across the bone when the heel is off the ground and the forefoot is planted. This type of fracture my also represent an old stress fracture which has progressed to a complete fracture. This type of fracture is significant because it occurs in an area where the blood supply to the bone is less than adequate, causing healing problems. The final type of fracture is the spiral or oblique shaft fracture. This type of fracture is located closer to the fifth toe. It may be caused by either direct trauma or by mechanical stresses placed across the bone. This type of fracture pattern is very unstable resulting in a fracture, which is often displaced.
After obtaining radiographs of your fractured fifth metatarsal, your physician may recommend a number of different treatments based on the type of fracture you have, your activity level, your age, and the amount of displacement of the fracture. Below is a discussion of different treatment options for the three types of fifth metatarsal fracture.
This type of fracture is treated most often with conservative or non-operative means. Because it is rarely significantly displaced, immobilization with either a surgical shoe or a removable cast boot will allow for adequate healing. This may require a period of six or more weeks before complete healing is noted on x-ray. In some instances, your doctor my recommend surgical treatment if the fracture is displaced or the fracture fragment is relatively large. If surgical treatment is indicated, your doctor may use various techniques to repair the fracture including screws, pins, or a technique known as tension band wiring. On rare occasions, the avulsed fracture fragment may fail to unite or heal; resulting in a small fragment of bone which may be very painful with walking or when it rubs on shoe gear. In these cases, your doctor may recommend that the fracture fragment simply be removed.
Because this type of fracture occurs in an area of diminished blood supply, this type of fracture often requires a more detailed treatment plan than that of the avulsion injury. Your physician may recommend a below knee fiberglass cast to be worn for a period of at least six weeks. He/she may or may not allow you to bear weight on this cast. In more active individuals, athletes, or in cases where the fracture has occurred due to a previous stress fracture, your doctor may suggest surgery as a better alternative. This will often decrease the number of weeks that cast immobilization is required, increase the healing rate, and decrease the risk of re-injury after the initial treatment. Your doctor may "fix" a Jones fracture by a number of different methods. Often times, a very small incision is used to place a “guided” or cannulated screw down the intramedullary canal of the fifth metatarsal bone.
Treatment of this fracture is typically based on the level of displacement that has occurred with the fracture. If there is minimal displacement or the fracture in incomplete your doctor may treat you with non-operative means. This may range from a surgical (wooden) shoe to a cast. Most likely, a period of restricted weight bearing will be required to allow for proper healing. If the fracture has separated or is displaced, surgical treatment is indicated. Your surgeon will often use screws or a combination of screws and a plate to repair your fracture. Although this fracture is relatively unstable, it lends itself nicely to fixation.
Regardless of which type of fifth metatarsal fracture you may have or which treatment modality your physician has recommended, it is important to follow your physician’s instructions. If the fifth metatarsal heals improperly, or fails to heal, a surgical procedure is often warranted to repair the situation. This can greatly lengthen your recovery time and reduce your chance for a pain free, satisfying result.