OR1.1-6 | Skeletal Trauma and Polytrauma Principles — Glossary

Accelerated degeneration of the disc level above or below a cervical or lumbar fusion, attributed to increased motion and loading at that level following fusion; occurs at approximately 2.5% per year after ACDF; a key driver for motion-preserving alternatives.

A spectrum of soft tissue reaction to cobalt-chromium debris in metal-on-metal hip arthroplasty, ranging from periprosthetic fluid collections to destructive pseudotumours; a leading cause of early revision in MoM implants.

A closed reduction technique for posterior hip dislocation in the supine patient: the operator applies upward longitudinal traction on the flexed hip and knee while the assistant presses down on the iliac crests to stabilise the pelvis; performed under anaesthesia.

The ratio of ankle systolic pressure to brachial systolic pressure; ABI <0.9 after knee dislocation indicates significant vascular injury and mandates CT angiography regardless of palpable distal pulse.

Surgical replacement of the ruptured ACL with a graft (bone-patellar tendon-bone, hamstring, or allograft); the ACL cannot be primarily repaired due to poor intrinsic healing; graft selection depends on patient age, activity level, and surgeon preference.

Failure of a joint replacement implant without infection, caused by periprosthetic osteolysis from wear debris (polyethylene particles activating macrophages → bone resorption); the most common long-term failure mode of total hip and knee arthroplasty.

Advanced Trauma Life Support — a standardised, globally used training programme developed by the American College of Surgeons that provides a systematic approach to the assessment and management of trauma patients using the ABCDE framework.

A four-tier classification of haemorrhagic shock based on estimated blood loss: Class I (<15% circulating blood volume), II (15–30%), III (30–40%), IV (>40%), with corresponding haemodynamic parameters used as a teaching and clinical decision framework.

Ischaemic necrosis of the femoral head following disruption of its blood supply (primarily the medial femoral circumflex artery) in hip dislocation; risk increases with delay in reduction beyond 6 hours and becomes very high after 12 hours.

A rapid neurological assessment tool for the primary survey grading four levels: Alert, responds to Voice, responds to Pain, Unresponsive; a simplified GCS equivalent for immediate triage purposes.

A fracture in which a tendon or ligament pulls off a fragment of the bone at its attachment; common examples include the fifth metatarsal base (peroneus brevis), anterior superior iliac spine (sartorius), and ischial tuberosity (hamstrings).

A branch of the posterior cord of the brachial plexus (C5, C6) that wraps around the surgical neck of the humerus, supplying the deltoid muscle (motor) and the lateral deltoid skin (sensory); the nerve most commonly injured in shoulder dislocation.

Avulsion of the anteroinferior glenoid labrum from the glenoid rim, the fundamental pathological lesion in anterior shoulder dislocation; a bony Bankart is an associated fracture of the anteroinferior glenoid rim.

The amount of base (in mEq/L) needed to restore blood pH to 7.4 at standard conditions; a negative base deficit (base excess below -6 mEq/L) indicates metabolic acidosis and correlates with Class III/IV haemorrhagic shock.

A family of osteoinductive growth factors that stimulate mesenchymal stem cell differentiation into osteoblasts; BMP-2 and BMP-7 are approved for specific spinal fusion and tibial non-union indications; off-label use associated with ectopic bone formation and other complications.

An autograft for ACL reconstruction taken from the central third of the patellar tendon with bone blocks at both ends; provides strong bone-to-bone healing in tunnels and is the gold standard for high-demand athletes, but causes donor-site morbidity including anterior knee pain.

An arthroplasty bearing surface using alumina or zirconia toughened alumina; the lowest wear of any bearing material, preferred in young high-demand patients; rare risks include fracture and squeaking.

A motion-preserving alternative to anterior cervical discectomy and fusion (ACDF) that implants a prosthetic disc, preserving segmental motion and potentially reducing adjacent segment disease; supported by multiple RCTs for single and two-level radiculopathy.

The lateral division of the sciatic nerve, wrapping around the fibular neck; injury causes foot drop (inability to dorsiflex and evert the foot) and numbness over the dorsum of the foot and first web space.

A condition in which elevated pressure within an osteofascial compartment exceeds capillary perfusion pressure, causing ischaemia of the muscles and nerves within; requires emergency fasciotomy within 6 hours of onset to prevent irreversible injury.

The reflex increase in heart rate triggered by reduced cardiac preload in haemorrhagic shock, mediated by sympathetic nervous system activation; may be blunted in elderly patients, those on beta-blockers, or athletes.

Surgical techniques using intraoperative imaging (CT, fluoroscopy, or navigation systems) to guide implant placement with precision exceeding freehand technique; reduces pedicle screw misplacement rates from ~12% to ~3%.

Soft tissue injury from blunt force compressing tissue against bone, rupturing small blood vessels and causing haematoma without skin breach; heals with RICE; large haematomas risk myositis ossificans if repeatedly traumatised.

An enzyme released by injured muscle cells; elevated in rhabdomyolysis (>1,000 U/L abnormal; >10,000 U/L severe); used to monitor the degree of muscle injury and response to treatment.

A staged surgical strategy for unstable orthopaedic injuries in haemodynamically compromised patients: initial temporary external fixation to control haemorrhage and alignment, with definitive fixation (IM nail, ORIF) deferred until physiology is restored.

A staged surgical strategy for unstable polytrauma patients: initial temporary external fixation to restore length and stability without physiological insult, followed by definitive fixation (IM nail, ORIF) in 3–5 days once the patient is haemodynamically optimised.

A physiological resuscitation strategy that prioritises early balanced blood product administration (FFP:pRBC:platelets in 1:1:1 ratio), permissive hypotension, and haemostatic interventions to prevent the lethal triad of coagulopathy, hypothermia, and acidosis.

A staged operative strategy in haemodynamically unstable trauma patients where the initial operation controls haemorrhage and contamination minimally, with planned re-operation after ICU resuscitation to restore normal physiology.

Separation of skin and subcutaneous tissue from the underlying fascia, disrupting the perforating blood vessels; may be open (skin avulsed) or closed (Morel-Lavallée, skin intact over a haemolymphatic cavity).

The difference between diastolic blood pressure and compartment pressure; a ΔP <30 mmHg indicates critically reduced capillary perfusion and mandates fasciotomy regardless of the absolute compartment pressure.

Complete loss of contact between the articular surfaces of a joint, classified by the direction of displacement of the distal bone relative to the proximal; a subluxation is partial loss of contact.

Surgical incision through the fascia to decompress a compartment in compartment syndrome; all four compartments of the leg are released through two longitudinal skin incisions, and wounds are left open for delayed closure.

Focused Assessment with Sonography in Trauma — a rapid bedside ultrasound survey of four windows (pericardial, right upper quadrant, left upper quadrant, pelvis) performed to detect free intra-abdominal or pericardial fluid.

The intrinsic cardiac property whereby increased ventricular filling (preload) stretches myocardial fibres, increasing stroke volume; in haemorrhagic shock, reduced preload from blood loss decreases stroke volume via this mechanism.

The period immediately following a traumatic injury during which prompt medical treatment is most likely to prevent death; originally proposed by R Adams Cowley, it emphasises urgency of intervention rather than a strict 60-minute biological limit.

A classification system for open fractures using three types (I/II/III, with III sub-classified as IIIA/B/C) based on wound size, contamination, and soft tissue involvement; Type IIIC indicates arterial injury requiring vascular repair.

The commonest form of hypovolaemic shock in trauma, caused by loss of intravascular blood volume; classified by the ATLS system into four classes (I–IV) based on volume lost and physiological response.

The strategy of replacing blood volume primarily with blood products (red cells, plasma, platelets) in a balanced ratio rather than crystalloid, to maintain coagulation capacity while restoring oxygen-carrying capacity.

The reinforcing cycle of hypothermia, acidosis, and coagulopathy in major soft tissue and skeletal trauma; each element worsens the others, driving haemorrhagic death if not interrupted.

A polyethylene bearing surface for total hip and knee arthroplasty in which irradiation cross-linking reduces wear by up to 95% compared to conventional polyethylene, dramatically reducing osteolysis and aseptic loosening.

A compression fracture of the posterolateral humeral head created as it impacts the anteroinferior glenoid rim during anterior shoulder dislocation; appears as a 'hatchet-shaped' defect on AP X-ray in internal rotation.

A fixation technique in which a metal rod is inserted into the medullary canal of a long bone; shares load centrally (load-sharing), preserves periosteal blood supply, and allows closed insertion that maintains the fracture biological environment.

A high-energy multi-ligamentous knee injury with complete disruption; associated with popliteal artery injury (30–40%) and common peroneal nerve injury (25%); requires ABI measurement and CT angiography if ABI <0.9.

A percutaneous procedure for osteoporotic vertebral compression fractures in which an inflatable balloon is inserted to restore vertebral height, followed by cement injection; provides pain relief and partial height restoration with reduced cement extravasation risk compared to vertebroplasty.

The mutually reinforcing combination of coagulopathy, hypothermia, and metabolic acidosis in major trauma, each worsening the others and collectively driving haemorrhagic death if not interrupted by damage control resuscitation.

An AP X-ray appearance in posterior shoulder dislocation where the internally rotated humerus appears abnormally rounded (like a lightbulb); axillary or Y-view is required to confirm the diagnosis.

A fixation system in which screw heads thread into and lock to the plate, creating a fixed-angle construct independent of bone-plate friction; enables stable fixation in osteoporotic bone and near articular surfaces where conventional screws would fail.

A technique for maintaining spinal alignment while turning a trauma patient to examine the back, typically requiring three people (head, torso, lower limbs) to rotate the patient as a single unit.

Arthroscopic suturing of meniscal tears, preferred over meniscectomy for peripheral vascular-zone tears in young patients; healing rates 85–90% for ideal candidates; preserves the load-distributing and shock-absorbing function of the meniscus.

An arthroplasty bearing surface using cobalt-chromium alloy on cobalt-chromium; largely abandoned after mass recalls due to elevated metal ion levels causing adverse local tissue reactions (ALTR), pseudotumour formation, and systemic toxicity.

Spinal procedures performed through tubular retractors or endoscopes that minimise paraspinal muscle stripping; reduces blood loss, hospital stay, post-operative pain, and muscle denervation compared to open surgery; now standard for single-level discectomy and selected fusions.

A closed degloving injury in which skin and subcutaneous tissue are sheared from deep fascia by tangential force, creating a haemolymphatic cavity; the overlying skin appears bruised and intact but is at risk of necrosis due to devascularisation.

Presence of myoglobin in urine, appearing as dark 'cola-coloured' urine; dipstick tests positive for 'blood' due to cross-reactivity, but microscopy shows no red blood cells — this discordance distinguishes it from haematuria.

Heterotopic (ectopic) bone formation within muscle, occurring after contusion or repeated haematoma; characterised by peripheral calcification on X-ray at 6–8 weeks; do not confuse with osteosarcoma (which has the reverse pattern — calcification central).

A complication in which a peripheral nerve becomes trapped within the joint during closed reduction, presenting as a NEW neurological deficit after reduction that was absent before; mandates urgent surgical exploration.

Distributive shock following cervical or high thoracic spinal cord injury, characterised by hypotension with paradoxical bradycardia and warm peripheries, caused by loss of descending sympathetic tone.

The mildest degree of peripheral nerve injury in which the nerve is compressed or stretched without axonal disruption; conduction is blocked but structural integrity is maintained; typically recovers fully within days to months.

A fracture in which the bone communicates with the external environment through a break in the overlying skin; classified by Gustilo-Anderson grade; requires antibiotics within 1 hour and surgical debridement as soon as feasible.

An anteroposterior compression pelvic injury characterised by widening of the pubic symphysis and disruption of anterior sacroiliac ligaments, dramatically increasing pelvic volume and enabling life-threatening retroperitoneal haemorrhage.

The biological fixation of a cementless implant through direct bone ingrowth and ongrowth into a porous or hydroxyapatite-coated surface, achieving durable long-term fixation; requires 6–12 weeks for primary stability to be achieved biologically.

Worsening of pain in the affected compartment on passive stretching of the muscles within it (e.g., passive dorsiflexion for anterior leg compartment); the earliest and most reliable clinical sign of compartment syndrome.

A circumferential compression device applied at the level of the greater trochanters in suspected open-book pelvic fractures, reducing pelvic volume to tamponade retroperitoneal venous haemorrhage; commercial binders or improvised sheet wraps are both effective.

The deliberate acceptance of a lower-than-normal blood pressure (typically systolic 80–90 mmHg) in haemorrhagic trauma until surgical haemorrhage control is achieved, to avoid dislodging clots and worsening coagulopathy; contraindicated in traumatic brain injury.

Dislocation of the proximal interphalangeal joint; most commonly posterior/dorsal from hyperextension with axial load; involves volar plate avulsion; treated with digital block, traction-reduction, and buddy taping.

Concentrated autologous platelets containing growth factors (PDGF, TGF-β, VEGF) injected to stimulate healing in tendinopathies and cartilage defects; moderate evidence for lateral epicondylitis; evidence insufficient for most other orthopaedic indications.

The principle that pre-hospital scene time should not exceed ten minutes; the pre-hospital analogue of the golden hour, emphasising rapid transport over prolonged on-scene interventions.

Disruption of the popliteal artery in knee dislocation due to its tight tethering at the adductor hiatus and soleal arch; diagnosed by ABI <0.9 or hard vascular signs; requires urgent vascular repair.

The commonest type of hip dislocation (90%), in which the femoral head is displaced posteriorly; caused by axial load on a flexed, adducted hip (dashboard injury); limb is held in flexion, adduction, and internal rotation; sciatic/peroneal nerve at risk.

The difference between systolic and diastolic blood pressure; narrows in early haemorrhagic shock as peripheral vasoconstriction raises diastolic pressure while systolic is maintained, making it a more sensitive early marker than systolic BP alone.

The patch of skin over the lateral deltoid supplied by the axillary nerve; numbness here after shoulder dislocation or proximal humeral fracture is the cardinal sign of axillary neuropraxia.

Breakdown of striated muscle cells releasing myoglobin, CK, potassium, and phosphate into the bloodstream; causes acute kidney injury through tubular myoglobin cast formation and ferrihemate toxicity, worsened by aciduria and dehydration.

Acute kidney injury caused by myoglobin-mediated tubular obstruction (cast nephropathy) and direct ferrihemate toxicity, worsened by aciduria; treated with aggressive IV fluid therapy targeting urine output 200–300 mL/h and urinary alkalinisation.

The largest nerve in the body, running posterior to the hip joint; at risk in posterior hip dislocation (10–14% injury rate); the common peroneal division is most vulnerable, causing foot drop.

The head-to-toe systematic physical examination and AMPLE history performed after completion of the ATLS primary survey and initial resuscitation, aimed at detecting all injuries not immediately life-threatening but clinically significant.

A biochemical marker of tissue hypoperfusion; elevated (>2 mmol/L) when cellular anaerobic metabolism produces lactic acid; serial measurements guide adequacy of resuscitation — falling lactate confirms effective treatment.

A smooth curved line connecting the inferior femoral neck and superior obturator foramen on AP pelvis X-ray; disruption confirms hip dislocation or femoral neck fracture; restoration after reduction confirms concentric reduction.

A state of inadequate tissue perfusion and oxygen delivery to meet cellular metabolic demands, leading to anaerobic metabolism, lactate accumulation, and multi-organ failure if untreated.

Temporary depression of all spinal cord function (reflexes, motor, sensory) below the level of a cord injury, lasting hours to weeks; a neurological phenomenon distinct from neurogenic shock, which is haemodynamic.

Simple Triage and Rapid Treatment — a widely used mass-casualty triage algorithm that classifies patients into Black/Red/Yellow/Green categories based on three parameters: respiratory status, radial pulse/perfusion, and ability to follow commands.

A gravity-assisted reduction technique for anterior shoulder dislocation — patient prone, arm hanging over table edge, 5–10 kg weight at wrist; muscle fatigue allows spontaneous reduction over 20–30 minutes.

A progressive accumulation of air in the pleural space under positive pressure, causing ipsilateral lung collapse, mediastinal shift away from the affected side, and ultimately cardiovascular collapse; a clinical emergency requiring immediate needle decompression.

A traction splint applied to femoral shaft fractures that maintains longitudinal traction to reduce fracture movement and haemorrhage into the thigh compartment, potentially reducing blood loss by 500–700 mL.

A device that applies longitudinal traction across a femoral shaft fracture to reduce muscle spasm, realign fracture fragments, and tamponade haemorrhage from torn periosteal and muscle vessels.

An antifibrinolytic drug that inhibits plasmin-mediated clot breakdown; shown by the CRASH-2 trial to significantly reduce mortality when given within 3 hours of injury in haemorrhagic trauma at a dose of 1 g IV over 10 minutes followed by 1 g over 8 hours.

Coagulation failure occurring early after major trauma, driven by tissue factor release, consumption of clotting factors, fibrinolysis activation, hypothermia, and acidosis; present in up to 25% of major trauma patients on arrival.

The process of sorting patients in a mass-casualty or multi-casualty incident into priority categories for treatment based on survivability and available resources, with the goal of maximising overall survival.

The three-peaked pattern of trauma deaths described by Trunkey: immediate (seconds to minutes, unsurvivable), early (minutes to hours, addressable by ATLS), and late (days to weeks, from multi-organ failure and sepsis).

Addition of sodium bicarbonate to IV fluids to maintain urine pH >6.5, reducing myoglobin precipitation and ferrihemate nephrotoxicity in rhabdomyolysis; adjunctive to aggressive fluid therapy.

A fibrocartilaginous structure on the palmar aspect of the PIP joint preventing hyperextension; avulsed from the base of the middle phalanx in dorsal PIP dislocation; large avulsions (>30–40% articular surface) require surgical fixation.

Permanent muscle fibrosis and contracture of the forearm and hand resulting from untreated or late-treated compartment syndrome of the forearm; characterised by a flexed wrist, flexed fingers, and clawed hand.