Orthopedic Board key terms

A system that grades pediatric growth-plate fractures by which bone and cartilage layers the fracture line crosses, from type I through type V, guiding prognosis and treatment because higher grades carry greater risk of growth disturbance.

A bridge of bone that forms across a growth plate after injury or infection, tethering that region and producing angular deformity or limb-length discrepancy as the surrounding physis continues to grow.

The capacity of immature bone to reshape after fracture through asymmetric apposition and resorption, greatest in young children and in fractures near the ends of long bones, allowing some angulation to correct over time.

A scheme for ankle fractures based on the level of the fibular fracture relative to the tibial plafond and syndesmosis, predicting stability and the likelihood of syndesmotic injury.

A system that names ankle fracture patterns by the foot position at injury and the direction of the deforming force, linking each mechanism to a predictable sequence of ligament and bone failure.

The fibrous connection between the distal tibia and fibula that holds the two bones together and allows the ankle mortise to accommodate the talus during motion.

A grading of femoral neck fractures in adults based on displacement and completeness, from nondisplaced incomplete through fully displaced, used to estimate the risk of avascular necrosis and guide treatment choice.

Death of bone tissue from loss of its blood supply, producing pain, collapse, and joint destruction; a feared complication after fractures of the femoral neck, talus, or scaphoid.

A curved band of altered signal just beneath the articular surface on MRI, indicating subchondral fracture or early collapse before plain films show changes.

The angle formed between the axis of the femoral neck and the femoral shaft, normally roughly 125 to 135 degrees; deviations describe coxa valga or coxa vara and affect hip biomechanics.

A grading of soft-tissue injury in closed fractures, from simple fractures with minimal soft-tissue damage to those with extensive crushing or compartment syndrome, used to guide urgency and treatment.

A grading of open fractures by wound size, soft-tissue damage, and contamination, ranging from a small clean puncture to extensive devitalized tissue, guiding antibiotic choice and surgical urgency.

The surgical removal of foreign material and dead or contaminated tissue from a wound until healthy, bleeding tissue remains, a core step in preventing infection in open injuries.

A condition in which rising pressure within a closed fascial space impairs capillary blood flow, threatening muscle and nerve; it presents with pain out of proportion, pain on passive stretch, and tense swelling.

A surgical opening of the fascia over a compartment to relieve pressure and restore perfusion, performed emergently when compartment syndrome is diagnosed or strongly suspected.

A staged approach in severely injured patients that uses rapid temporary stabilization, such as external fixation, to control hemorrhage and soft-tissue injury before definitive surgery once the patient is physiologically stable.

Injury involving multiple body regions or organ systems, at least one of which is life-threatening, requiring coordinated assessment and prioritized treatment to avoid missing injuries and to limit physiologic deterioration.

A structured initial assessment of a trauma patient addressing airway, breathing, circulation, disability, and exposure in sequence, aimed at identifying and treating immediately life-threatening problems before detailed examination.

A method of stabilizing bone with pins or wires inserted into bone and connected by bars outside the limb, useful for open fractures, severe soft-tissue injury, and temporary damage-control stabilization.

Use of a circular external frame with tensioned wires to stabilize bone and, through gradual controlled distraction, to lengthen bone or correct deformity by exploiting the body's capacity to generate new bone.

The controlled separation of bone ends after an osteotomy, allowing new bone to fill the gap, used to lengthen limbs or correct deformity while preserving soft-tissue and neurovascular function.

The principle that bone adapts its structure to the loads placed on it, adding mass where stress is high and resorbing where it is low, explaining changes seen with activity, disuse, and implant shielding.

Reduction of mechanical load on bone caused by a stiff implant carrying stress instead, leading to bone loss around the device and potential loosening over time.

The continuous coupled process in which osteoclasts resorb old bone and osteoblasts form new bone, repairing microdamage and adapting the skeleton to mechanical demands throughout life.

The property of a material that supports the ingrowth of bone by providing a scaffold for cells to migrate and new bone to form, without itself stimulating cell differentiation.

The process by which a material or factor, such as bone morphogenetic protein, recruits and stimulates undifferentiated cells to become bone-forming cells, actively driving new bone formation.

Material placed in a defect to promote healing, which may be autograft, allograft, or synthetic, and which works through combinations of osteoconduction, osteoinduction, and living cell transfer.

Failure of a fracture to heal within an expected time with no further progress toward union, often associated with instability, poor blood supply, infection, or adverse biology, and usually requiring intervention.

Healing of a fracture in an unacceptable position, resulting in deformity, altered mechanics, or functional limitation, which may require corrective osteotomy if symptoms warrant.

A fracture that is slower than expected to heal but still shows signs of progress, generally managed with continued observation and correction of contributing factors such as instability or poor biology.

A fracture occurring near or around an implanted orthopedic device, often after low-energy trauma in bone weakened by the implant, requiring assessment of implant stability and bone stock to plan fixation or revision.

Failure of an implant fixation without infection, driven by mechanical and particle-related processes, presenting with progressive pain and radiographic signs such as widening radiolucent lines or component migration.

Localized bone loss caused by an inflammatory response to wear particles around an implant, producing radiolucent lesions that can weaken bone and contribute to implant loosening.

Measures of a test's performance: sensitivity is the proportion of people with disease who test positive, and specificity is the proportion without disease who test negative, independent of disease prevalence.

The probability that a person with a positive test result truly has the disease, which depends on disease prevalence in the tested population as well as the test's sensitivity and specificity.

A ratio comparing how likely a test result is in people with disease versus those without, used to update the probability of disease after a test and less dependent on prevalence than predictive values.

The number of patients who must receive an intervention for one additional patient to benefit, calculated as the reciprocal of the absolute risk reduction, reflecting clinical impact of a treatment.

A ranking of study design quality used to judge the strength of a recommendation, from high-quality randomized trials and systematic reviews down to case reports and expert opinion.

A range of values within which the true effect is estimated to lie with a stated probability, conveying the precision of a study result and whether an estimate excludes a meaningful effect.