The wrists are subjected to various types of injuries whether by playing sports or during daily activities. One of the common injuries is hairline fractures of the wrists that vary depending on the part or region affected. Injuries can occur from accidental falls onto an extended hand or during a vehicular accident.
Anatomy of the wrist
The bones in the wrist are aligned to enable the wrist to move in various directions. The radius is situated on the thumb side of the hand. As for the ulna, it is a narrower bone on the little finger side of the hand. There is a sturdy membrane that connects the radius and ulna in the forearm. Simple movements occur at the joint in between the radius and ulna in the wrist.
A triangular fibrous cartilaginous complex is positioned in between the ulna and carpal bones which is known as the TFCC. This structure forms an arch together with the radius surface. Most of the wrist movements occur when the 8 carpal bones move on the radius and ulna.
Close look on hairline fractures
Hairline fractures are considered as non-displaced fractures that do not cause deformity of the bone. If evident on an X-ray that is taken soon after the injury, the injury appears as an indistinct line. Within 7-14 days, bone is reabsorbed during the healing process. The hairline fractures that were not initially evident manifest as a clear line on the X-ray. The new calcified bone is formed at the site of the fracture. After 14 days, hairline fractures appear as a dense white line on the X-ray result.
Radius hairline fractures
The hairline fractures on the radius typically occur 1-2 cm from the joint across the styloid or within the joint. This type of fracture is managed with a splint or cast.
Ulna hairline fractures
The protuberant region of the ulna is the styloid. The ligaments in the wrist connect here as well as the TFCC. Accidental falls that involve twisted movements can lead to TFCC tears. In most cases, these are managed with casting.
Scaphoid hairline fractures
The scaphoid is essential in stabilizing the carpal bone. Once the scaphoid hairline fracture does not seem to heal, it can lead to the collapse of the carpal bones. Possible hairline fractures of the scaphoid are managed with a cast that includes the thumb. An X-ray can be repeated 10-14 days after to check if a fracture is present. The cast is in place until the fracture fully heals.
The hairline fractures of the wrist that are managed typically heal without any complications. After a cast is applied, many individuals will experience stiffness for a month. Individuals who sustained wrist fractures should be encouraged to utilize their fingers to reduce the stiffness.
After 3-6 months after the fracture, the individual can resume his/her sport. Any unusual symptoms must be reported to a doctor. In rare occasions, the nerves might become stimulated after the fracture which results to a sore condition known as reflex sympathetic dystrophy.