Bony crepitation is a palpable vibration or an audible crunching sound that results when one bone grates against another. This sign commonly results from a fracture, but it can also occur when bones that have been stripped of their protective articular cartilage grind against each other as they articulate—for example, in patients with advanced arthritic or degenerative joint disorders.
Eliciting bony crepitation can help confirm the diagnosis of a fracture, but it can also cause further soft tissue, nerve, or vessel injury. Always evaluate distal pulses and perform neurologic checks distal to the suspected fracture site before manipulating an extremity. In addition, rubbing fractured bone ends together can convert a closed fracture into an open one if a bone end penetrates the skin. Therefore, after the initial detection of crepitation in a patient with a fracture, avoid subsequent elicitation of this sign.
HISTORY AND PHYSICAL EXAMINATION
If you detect bony crepitation in a patient with a suspected fracture, ask him if he feels any pain and if he can point to the painful area. To prevent lacerating nerves, blood vessels, or other structures, immobilize the affected area by applying a splint that includes the joints above and below the affected area. Elevate the affected area, if possible, and apply cold packs. Inspect for abrasions or lacerations. Find out how and when the injury occurred. Palpate pulses distal to the injury site, and check the skin for pallor or coolness. Test motor and sensory function distal to the injury site.
If the patient doesn’t have a suspected fracture, ask about a history of osteoarthritis or rheumatoid arthritis. Do any medications help ease arthritic discomfort? Take the patient’s vital signs and test joint range of motion.
Fracture. In addition to bony crepitation, a fracture causes acute local pain, hematoma, edema, and decreased range of motion. Other findings may include deformity, point tenderness, discoloration of the limb, and loss of limb function. Neurovascular damage may cause increased capillary refill time, diminished or absent pulses, mottled cyanosis, paresthesia, and decreased sensation (all distal to the fracture site). An open fracture produces an obvious skin wound.
Osteoarthritis. Joint crepitation may be elicited during range-of-motion testing in advanced osteoarthritis. Soft fine crepitus on palpation may indicate roughening of the articular cartilage; coarse grating may indicate badly damaged cartilage. The cardinal symptom of osteoarthritis is joint pain, especially during motion and weight bearing. Other findings include joint stiffness that typically occurs after resting and subsides within a few minutes after the patient begins moving.
Rheumatoid arthritis. In advanced rheumatoid arthritis, bony crepitation is heard when the affected joint is rotated. However, this disorder usually develops insidiously, producing nonspecific signs and symptoms, such as fatigue, malaise, anorexia, a persistent low-grade fever, weight loss, lymphadenopathy, and vague arthralgias and myalgia. Later, more specific and localized articular signs develop, commonly at the proximal finger joints. These signs usually occur bilaterally and symmetrically and may extend to the wrists, knees, elbows, and ankles. The affected joints stiffen after inactivity. The patient also has increased warmth, swelling, and tenderness of affected joints as well as limited range of motion.
If a fracture is suspected, prepare the patient for X-rays of the affected area, and reexamine his neurovascular status frequently. Keep the affected part immobilized and elevated until treatment begins. Give an analgesic to relieve pain.
Bony crepitation in a child usually occurs after a fracture. Obtain an accurate history of the injury, and be alert for the possibility of child abuse. In a teenager, bony crepitation and pain in the patellofemoral joint help diagnose chondromalacia of the patella.
Degenerative joint changes, which have usually begun by age 20 or 30, progress more rapidly after age 40 and occur primarily in weight-bearing joints, such as the lumbar spine, hips, knees, and ankles.