Fracture Fundamentals

Fractures: Types, Causes, and Symptoms

• A fracture is a break in the structural continuity of bone, which can be caused by injury, repetitive stress, or abnormal weakening of the bone.
• Fractures due to injury are caused by sudden and excessive force, which may be direct or indirect, and can result in a closed or open fracture.
• The dominant mechanism of a fracture is revealed by X-rays, where twisting causes a spiral fracture, compression causes a short oblique fracture, bending results in a fracture with a triangular 'butterfly' fragment, and tension tends to break the bone transversely.
• Fatigue or stress fractures occur in normal bone subjected to repeated heavy loading, typically in athletes, dancers, or military personnel.
• Pathological fractures can occur even with normal stresses if the bone has been weakened by a change in its structure or through a lytic lesion.
• Fractures can be complete or incomplete, with the bone split into two or more fragments in complete fractures, while the bone is incompletely divided and the periosteum remains in continuity in incomplete fractures.
• Transverse fractures usually remain in place after reduction, while oblique or spiral fractures tend to shorten and redisplace even if the bone is splinted.
• Impacted fractures have tightly jammed fragments with an indistinct fracture line, while comminuted fractures have more than two fragments with interlocking of the fracture surfaces and are often unstable.
• Greenstick fractures occur when the bone is buckled or bent and are seen in children.
• Compression fractures occur when cancellous bone is crumpled, typically in adults where this type of bone structure is present, such as in vertebral bodies, calcaneum, and the tibial plateau.
• Symptoms of a fracture include pain, swelling, bruising, deformity, and difficulty moving the affected area.
• Treatment for a fracture depends on the type and severity of the fracture and may involve immobilization, medication, surgery, or physical therapy.

How Fractures Heal

• Fracture healing involves new bone formation and fusion of the bone fragments.
• The bone can heal by primary (without callus formation) or secondary (with callus formation) fracture healing.
• The healing process varies based on the type of bone involved and the amount of movement at the fracture site.
• Absolute stability and compression lead to direct healing, while relative stability leads to indirect healing.
• Excessive motion can lead to delayed or non-union.
• Callus formation occurs in response to movement at the fracture site and stabilizes the fragments for bridging by new bone formation.
• Most fractures are splinted to alleviate pain, ensure good position, and permit early movement and function.
• Primary bone healing occurs when the fracture site is absolutely stable and osteoblastic new bone formation occurs directly between fragments.
• Healing by callus is the most common form of healing in tubular bones and ensures mechanical strength while bone ends heal.
• Healing by callus proceeds in five stages: hematoma formation, inflammation, soft callus formation, hard callus formation, and remodeling.
• The periosteum is an excellent source of local mesenchymal stem cells that can enhance bone repair.
• It is imperative to leave the periosteum in place and viable for bone repair.