OR2.10-13 | Lower Limb Fractures — Glossary

The ratio of the ankle systolic blood pressure to the brachial systolic blood pressure; a value <0.9 indicates significant arterial occlusion and mandates vascular surgery consultation.

The bony socket formed by the medial malleolus, tibial plafond (roof), and fibula that receives the trochlea of the talus; its structural integrity depends on the lateral malleolus, medial malleolus, syndesmosis, and deltoid ligament acting as a coupled system.

The primary restraint to anterior fibular displacement and the first ligament disrupted in supination-external rotation ankle injuries (SER Stage I); its avulsion from the fibular attachment produces a small fragment called a Wagstaffe fracture; injury is detected by anterior syndesmotic tenderness and a positive external rotation stress test.

A universal hierarchical fracture classification system developed by the AO Foundation and Orthopaedic Trauma Association, used to characterise fractures by bone segment and morphology (A = extra-articular, B = partial articular, C = complete articular) for communication and research.

A severe form of acute respiratory failure characterised by bilateral pulmonary infiltrates, PaO₂/FiO₂ <200 mmHg, and non-cardiogenic pulmonary oedema; fat embolism syndrome may progress to ARDS pattern if endothelial injury is extensive.

A fracture involving both the lateral malleolus (fibula) and the medial malleolus; the medial and lateral pillars of the ankle mortise are both disrupted, rendering the mortise unstable with lateral talar shift; standard treatment is ORIF.

A radiographic measurement on the lateral calcaneus view representing the angle between two lines drawn from the highest point of the anterior process to the highest point of the posterior facet, and from the highest point of the posterior facet to the superior border of the tuberosity; normal range 20–40°; values <20° indicate posterior facet depression in calcaneus fractures.

The transplantation of bone tissue (autograft from the iliac crest, allograft from a bone bank, or synthetic substitute) to fill a void left after reduction of a depressed articular fracture, preventing secondary collapse of the repaired surface.

The yellow marrow (fat cells and adipocytes) within the medullary cavity of long bones; at the time of fracture or during intramedullary nail insertion, fat globules are released into disrupted intramedullary venous sinusoids and enter the systemic venous circulation, initiating fat embolism syndrome.

A tibial plateau fracture caused by the direct impact of a vehicle bumper on the lateral knee, typically producing a Schatzker Type I or II lateral split or split-depression fracture; the term reflects the classic road traffic accident mechanism.

A branch of the sciatic nerve that winds around the fibular neck to supply the anterior and lateral compartments of the leg; it is vulnerable to traction and direct injury in knee dislocations, fibular neck fractures, and proximal tibia injuries, causing foot drop and loss of dorsiflexion.

A limb-threatening condition in which pressure within a closed fascial compartment rises above capillary perfusion pressure, causing microvascular ischaemia to muscles and nerves despite potentially patent major vessels; treated with emergency fasciotomy.

A limb-threatening condition in which pressure in one or more of the four muscle compartments of the leg rises above microvascular perfusion pressure; earliest signs are pain out of proportion and pain on passive stretch; treated by four-compartment fasciotomy when compartment pressure >30 mmHg or ΔP <30 mmHg.

An intraoperative fluoroscopic stress test for syndesmotic instability: the heel is grasped and a lateral translation force applied while the mortise is viewed on fluoroscopy; >2 mm lateral translation indicates syndesmotic disruption requiring fixation.

A staged surgical strategy for polytrauma patients in which temporary external fixation is applied first to stabilise fractures and control haemorrhage, with definitive internal fixation deferred until the patient is physiologically stable (corrected acidosis, coagulopathy, and hypothermia).

The strong medial collateral ligament complex of the ankle consisting of deep (tibiotalar) and superficial (tibionavicular, tibiocalcaneal, tibiospring) layers; it resists lateral talar shift and external rotation of the talus; its rupture results in medial clear space widening and mortise instability.

The difference between diastolic blood pressure and the measured intracompartmental pressure; a ΔP <30 mmHg is a standard threshold for emergency fasciotomy in compartment syndrome.

The integrated functional unit of quadriceps muscle, quadriceps tendon, patella, patellar tendon, and tibial tubercle that enables active knee extension; disruption at any point results in inability to extend the knee against gravity.

A fracture fixation method using pins or wires inserted through the bone connected to an external frame outside the limb; used as damage control for severely contaminated open fractures (Grade IIIB/IIIC) or in patients not fit for definitive surgery; can be converted to intramedullary nail after wound control is achieved.

Surgical incision of the fascial envelope surrounding one or more muscle compartments to relieve elevated intracompartmental pressure and restore microvascular perfusion; the definitive treatment for compartment syndrome.

A clinical syndrome characterised by the triad of respiratory failure, neurological dysfunction, and petechial rash, caused by fat globules entering the systemic circulation after long bone fractures or major orthopaedic procedures; typically manifests 24–72 hours after the precipitating event.

Regional anaesthetic technique in which local anaesthetic is injected around the femoral nerve in the femoral triangle to provide analgesia for femoral shaft fractures; it reduces opioid requirements and attenuates the sympathetic stress response associated with severe pain.

A small avulsion fracture fragment at the base of the second metatarsal adjacent to the Lisfranc ligament, visible on plain radiograph; pathognomonic of Lisfranc ligamentous rupture when present.

Elastic nailing of long bone fractures in children aged approximately 5–11 years using two flexible titanium or stainless steel nails introduced from the distal metaphysis; it avoids the proximal femoral physis and allows controlled fracture reduction without reaming.

Surgical decompression of all four muscle compartments of the leg (anterior, lateral, deep posterior, superficial posterior) through two longitudinal incisions (anterolateral and posteromedial), the standard treatment for compartment syndrome of the leg.

A form of skin traction used for femoral shaft fractures in infants under 18 months of age, in which both lower limbs are suspended vertically using adhesive skin traction straps and the child's body weight provides the traction force; it is safe only in this age group due to the low body weight.

The standard diagnostic framework for fat embolism syndrome, requiring at least one major criterion (petechiae, PaO₂ <60 mmHg, CNS depression, or pulmonary oedema) plus at least one minor criterion and laboratory evidence of fat macroglobulinaemia; developed by Gurd and Wilson (1974).

The standard classification of open fractures (Grade I/II/IIIA/IIIB/IIIC) based on wound size, degree of contamination, and soft tissue damage; Grade IIIC involves arterial injury requiring repair.

Bleeding into a joint space, characterised by a tense, warm effusion; in the context of the knee, it strongly suggests intra-articular pathology such as a patellar fracture, tibial plateau fracture, or ligamentous tear.

The proportion of blood volume occupied by red blood cells (expressed as a percentage); a sudden drop in haematocrit after femoral shaft fracture reflects acute blood loss into the thigh and is listed among the minor criteria for fat embolism syndrome when associated with other features.

A form of distributive shock resulting from acute blood loss; classified by ATLS into four classes based on estimated volume loss, physiological changes, and clinical findings: Class I (<15%), Class II (15–30%), Class III (30–40%), Class IV (>40% blood volume).

A metal rod inserted into the medullary cavity of a long bone and secured with interlocking screws proximally and distally; the gold standard definitive fixation for femoral shaft fractures, providing axial, bending, and rotational stability while allowing early weight-bearing.

A metal rod inserted through the tibial tubercle region into the medullary canal of the tibia, locked proximally and distally; the standard operative treatment for displaced closed tibial shaft fractures, providing rotational and length stability while permitting early weight-bearing.

A transverse fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal (approximately 1.5–2 cm from the styloid tip), occurring in the watershed zone of poor blood supply; carries a high non-union risk; requires operative fixation (intramedullary screw) in active patients.

A mechanistic classification of ankle fractures based on foot position (supination or pronation) at the time of injury and the direction of the deforming force (adduction, external rotation, abduction); it predicts the sequential injury pattern (ligamentous before bony) and correlates with the Weber classification.

The presence of fat globules in the urine, detectable by Sudan staining of urinary sediment; a minor criterion in the Gurd classification of fat embolism syndrome, reflecting renal capillary fat embolisation.

The tarsometatarsal joint complex, comprising the articulations between the five metatarsal bases and the three cuneiforms and cuboid; stabilised by the Lisfranc ligament (medial cuneiform to 2nd metatarsal base), which is the keystone of the medial longitudinal arch and the primary stabiliser of the midfoot.

The strong interosseous ligament running between the medial cuneiform and the base of the second metatarsal; it is the primary stabiliser of the Lisfranc joint complex; its rupture results in diastasis between the first and second metatarsal bases on AP foot X-ray.

A fixation implant in which screws lock into threaded holes in the plate, creating a fixed-angle construct that provides angular stability even in osteoporotic or comminuted bone; widely used for periarticular fractures of the distal femur and tibial plateau.

A high spiral fracture of the proximal fibula associated with complete syndesmotic disruption and medial-side injury (medial malleolus fracture or deltoid rupture), caused by a pronation-external rotation (PER) mechanism; it is typically missed because standard ankle radiographs do not include the proximal fibula — a widened mortise without a visible distal fibular fracture mandates imaging of the full fibula.

A stress fracture of a metatarsal shaft (most commonly the 2nd or 3rd) occurring from repetitive loading in unaccustomed activity; plain radiographs are normal in the first 2 weeks; periosteal reaction appears at 2–3 weeks; managed with activity modification and protected weight-bearing.

The radiographic distance between the medial aspect of the talus and the articular surface of the medial malleolus on the mortise view; normal value <4 mm (should equal the superior joint space); MCS ≥5 mm indicates deltoid ligament rupture or medial malleolus fracture-gap.

The standard operative technique for unstable ankle fractures: surgical exposure, anatomic reduction of displaced fractures under direct vision, and fixation with plates and screws; the fibula is fixed first (restoring length and rotation), followed by the medial malleolus and posterior malleolus, then syndesmotic fixation if needed.

A validated clinical decision instrument that specifies when ankle or foot radiographs are required after ankle injury; radiographs are needed only if there is pain in the malleolar or midfoot zone AND one of: bony tenderness at the posterior malleolar edges, navicular, or fifth metatarsal base, or inability to weight-bear; sensitivity approaches 100% for significant fractures.

A fracture occurring through bone that has been structurally weakened by a pre-existing disease process such as malignancy (primary or metastatic), infection, metabolic bone disease, or Paget's disease; the hallmark is a disproportionately low-energy mechanism relative to the fracture severity.

Small (<3 mm) pinpoint haemorrhagic spots caused by capillary rupture; in fat embolism syndrome they appear over the upper chest, anterior axillary folds, and conjunctivae due to fat globule occlusion of dermal and conjunctival capillaries — the pathognomonic clinical sign of FES.

A clinical examination technique for Lisfranc injury: the examiner applies longitudinal pressure along the axis of each metatarsal while the ankle is stabilised; pain at the tarsometatarsal joint level (rather than the metatarsal shaft) on axial loading is highly specific for Lisfranc instability.

The entry point for antegrade femoral intramedullary nailing, located at the tip of the greater trochanter at the junction with the posterior cortex of the femoral neck; the trochanteric entry point is an alternative used in many modern nail systems.

Bruising in the plantar arch of the foot after a midfoot twisting injury, caused by plantar capsule and Lisfranc ligament disruption; considered pathognomonic of Lisfranc injury and mandates further investigation with weight-bearing radiographs or CT.

The continuation of the femoral artery through the popliteal fossa, tethered proximally at the adductor hiatus and distally at the popliteal fossa; its proximity to the distal femur and proximal tibia makes it vulnerable in peri-knee fractures.

The most important long-term complication of missed or inadequately treated Lisfranc fracture-dislocation; characterised by painful collapse of the medial longitudinal arch, difficulty with weight-bearing, and inability to return to sporting activities; prevented by anatomic reduction and fixation of the TMT complex acutely.

The posterior lip of the tibial plafond (sometimes called the third malleolus or Volkmann's fragment); fractured in trimalleolar injuries; fixation is required if the fragment is >25% of the articular surface on lateral view or is displaced >2 mm, as these criteria indicate instability and risk of posterior subluxation of the talus.

An avulsion fracture of the styloid process (tip) of the fifth metatarsal caused by traction from the peroneus brevis tendon or lateral band of the plantar fascia; distinct from a Jones fracture; managed conservatively with a firm shoe for 4–6 weeks.

A type of intramedullary nail inserted through the intercondylar notch of the femur in a retrograde direction (from distal to proximal) to stabilise distal femur fractures; preserves the knee joint and allows early mobilisation.

A CT-based classification of intra-articular calcaneus fractures (Types I–IV) based on the number of articular fragments in the posterior facet on coronal CT images; Type I = non-displaced; Type II = two-part; Type III = three-part; Type IV = comminuted, four-part; guides operative versus non-operative decision-making.

A method of non-operative fracture management using a custom-moulded below-knee functional brace (patellar tendon-bearing cast or brace) that allows early weight-bearing and joint motion; used for stable closed tibial shaft fractures with acceptable alignment.

A six-type classification system for tibial plateau fractures (I–VI) based on fracture morphology and energy level; Types I–III are lower energy lateral injuries and IV–VI are higher energy medial or bicondylar injuries carrying greater complication risk.

A long bone fracture in which two separate fracture planes create an isolated central fragment (floating segment); in femoral shaft fractures, segmental patterns are high-energy injuries associated with greater blood loss and more challenging fixation.

A tangential radiographic projection of the patella taken with the knee flexed 30–45°, allowing assessment of the patellofemoral joint space and patellar fracture patterns in the axial plane; also called the Merchant view.

A clinical test for syndesmotic injury: the tibia and fibula are compressed together at the mid-leg level while the ankle hangs free; pain referred distally to the syndesmosis is a positive result, indicating possible syndesmotic disruption.

Surgical fusion of the subtalar (talocalcaneal) joint; indicated as primary treatment for highly comminuted Sanders Type IV calcaneus fractures and as late salvage for post-traumatic subtalar arthritis following calcaneal fracture; it eliminates painful hindfoot motion but preserves ankle motion.

The most common ankle fracture pattern (60–70%), produced by an external rotation force on a supinated foot; SER Stage IV involves a spiral/oblique fibular fracture at the syndesmosis level plus medial malleolus fracture or deltoid ligament rupture, constituting an unstable bimalleolar-equivalent injury.

An alternative to trans-syndesmotic screws for syndesmotic fixation; a high-strength suture passed through the tibia and fibula and anchored with buttons on each cortex; it allows physiological micromotion of the fibula during ankle flexion and does not require hardware removal, unlike rigid cortical screws.

The fibrous joint between the distal tibia and fibula, maintained by the anterior and posterior inferior tibiofibular ligaments, the inferior transverse ligament, and the distal interosseous membrane; it maintains the mortise width and allows 1–2 mm of physiological fibular motion during dorsiflexion.

The joints between the five metatarsal bases and the three cuneiforms (medial, intermediate, lateral) plus the cuboid, forming the Lisfranc joint complex; these joints are the transition between the rigid midfoot and the more mobile forefoot and are essential to normal medial longitudinal arch function.

An operative fixation principle in which a cerclage wire is placed on the tension side of a fracture, converting the distracting tensile force into compressive force at the fracture site; classically applied to patellar and olecranon fractures.

An emergency splint consisting of a padded ring at the proximal thigh and two parallel metal rods extending to the foot, used to immobilise femoral shaft fractures; it converts longitudinal traction to the fracture site, reducing pain and blood loss.

The radiographic distance between the medial border of the fibula and the lateral border of the posterior tibial line on the standard AP and mortise views; normal value <5 mm; a TFCS ≥5 mm indicates syndesmotic widening.

A fracture involving the lateral malleolus, medial malleolus, and the posterior malleolus (Volkmann's fragment — the posterior lip of the tibial plafond); management involves ORIF of fibula, medial malleolus, and posterior malleolus (if >25% articular surface or >2 mm displaced), followed by syndesmotic assessment.

A classification of ankle fractures based on the level of the fibular fracture relative to the syndesmosis: Weber A (infrasyndesmotic — below syndesmosis, stable), Weber B (transsyndesmotic — at syndesmosis, stability depends on medial side), and Weber C (suprasyndesmotic — above syndesmosis, typically unstable).