Lower limb trauma

 

Lower limb traumaBone lesions of the pelvic girdle:

Fractures of the pelvic girdle are common but account for only 2-3% of all fractures in public road accidents. The basin constitutes a continuous ring which presents three points of weakness: in front, the ischiopubian complex; laterally, the cotyles; in the rear, the ilio-sacral complex.

The standard radiographic assessment rests essentially on four images: frontal pelvis; hemibasin traumatized from the face, wing oblique, unwinding the iliac wing, exploring the posterior border of the iliac bone and the anterior margin of the acetabulum; obturator oblique which studies the superior strait, the posterior edge of the acetabulum and the obturator frame. Two additional shots can be made: “outlet” or ascending face that releases the upper and lower branches of the pubis; “Inlet” or descending face which allows a good visualization of the sacrum.

Fractures of the pelvis:

They are secondary to a violent trauma and result from antero-posterior or latero-lateral direct compression forces and / or vertical shear forces by falling from a high place (it is necessary to look for lesions of the associated transverse processes). The lesional associations, homo lateral or crossed, are multiple and factors of instability. They present a major hemorrhagic risk and for some of the visceral or neurological risks.

Posterior lesions:

The lesions of the sacroiliac joints include pure disjunctions and fractures-disjunctions. These two entities constitute equivalents of posterior vertical fracture. Vertical fractures of the sacrum (posterior of the pelvis) are always associated with anterior vertical fractures of the pelvic ring. Gravity depends on the impact on the sacred roots. The diagnosis on standard radiographs is inconstant.

Lesions of the anterior arch:

These are pubic symphysic fractures and disjunctions. They are easy to diagnose on standard radiographs. Isolated fractures are stable but exceptional; their finding therefore imposes the realization of a CT scan to look for an associated lesion of the posterior arch. These associations are factors of instability especially since they are often crossed.

Lesions of the iliac wing:

Sub-peritoneal hematoma is particularly common in this setting. Isolated fractures, by direct impact, are more rare (direct impact on motorcycle accidents).

What to do?

CT has triple interest in emergency or delayed manner: the more accurate assessment of the lesions (unrecognized posterior fracture or radioclinic discordance); the search for deformations of the pelvic ring generating highly disabling vicious callus in young women for future pregnancies; the search for hematoma and visceral lesion.

Urogenital trauma is associated with rupture of the anterior arch with shearing of the pelvic floor.

Bladder insertion by a bony spine is anecdotal, while a tear, or even a section of the urethra, is frequent in humans.

Direct lesions of the iliac vessels or hypogastric by shearing or by bone perforation are in fact quite rare. Emergency haemostasis or embolization of the gluteal artery or trunk of the hypogastric is then necessary. Sometimes, emergency stabilization with an external fixative alone helps to stabilize the bleeding.

Fractures of the acetabulum:

During traumatic shocks of the pelvis, traumatic forces are transmitted to the femoral head, which acts as an anvil; in the previous impacts transmitted through the femoral neck, the head acts as a “bumper”.

The seat of the lesions then depends on the degree of abduction and flexion of the hip at the time of the impact (posterior fractures), or on the degree of external rotation (anterior fractures).

Four types of fractures constitute more than 75% of the fractures of the acetabulum (posterior wall 27%, transverse 9%, associated with each other 20%, anterior column 5%, posterior column 4%, associated with each other 20%).

Posterior wall fracture:

Due to their mechanism of occurrence, they are often secondary to posterior femoral dislocation. The finding of a fracture of the posterior wall should suggest a spontaneously dislocated luxation. The fracture line is oblique sagittal whereas all other landmarks are intact. The discovery of a luxated or off-centered femoral head must make search for an impaction zone or an incarcerated fragment.

Posterior column fracture:

The posterior dislocations of the femoral head are frequent and the risk of lesion of the sciatic nerve.

The frontal fracture line generally runs from the region of the large sciatic notch towards the posterior part of the back of the acetabulum and ends on the ischiopubic branch. The rear column is moved back and in internal rotation.

Fracture of the anterior wall:

Like fractures of the anterior column, this lesion results from lateral forces applied to the greater trochanter.

The line originates at the level of the anterior cotyloid brow and ends on the outer part of the iliopubian branch.

The line is generally comminutive and carries the front part of the roof. Often, this fracture is associated with a quadrilateral surface flap pressed in and out, while the anterior wall moves forward and inward.

Fracture of the anterior column:

Most often, it is associated with a posterior column fracture or a transverse fracture. The integrity of the ischiopubic branch makes it possible to eliminate a fracture of the anterior wall. The line has a frontal orientation.

It descends and cuts the roof on its anterior sector, the background and the ischiopubic indentation.

There is sometimes a split in the background leading to a broad endopelvic strand. This fracture is characterized essentially by its displacement in external rotation with winding upwards and forwards.

Cross-sectional fracture:

Its line divides the iliac bone into two segments: an upper segment, iliac, attached to the sacrum and therefore stable, and an inferior, ischiopubic, unstable segment. This cleavage plane always passes through the center of the femoral head, which can be dislocated within (central dislocation). The search for a lesion of the sacroiliac joints must be systematic; in fact, this transverse fracture interrupts the pelvic ring at a single point and the disruption (even minimal) of the sacroiliac is constant and realizes the second point of rupture.

Associated fractures:

They combine at least two of the elementary forms already described and divide the iliac bone into more than two fragments: transverse fracture plus posterior wall fracture; fracture of the two columns; T-fracture which can be assimilated to a transverse fracture with a vertical foot that interrupts the background of the acetabulum and the ischiopubic branch; fracture of the anterior wall or anterior posterior hemitransversal column; fracture of columns plus posterior wall.

What to do?

The background of the acetabulum is difficult to explore in standard radiography; the scanner is the technique of choice for evaluating bone fragments and their displacement, impactions, diastasis, intra-articular fragments; it will be best done after pulling. Early complications are relatively rare (compression of the sciatic nerve).

In the long term, hip osteoarthritis is usually the result of persistent joint incongruence.

The fate of the femoral head is practically fixed at the time of the trauma and whatever the quality of the surgical reduction, the necrosis may appear.

Hip dislocations:

They do not in principle pose any diagnostic difficulty on the 4 standard photographs systematically realized. They must be reduced urgently before CT scanning, especially because of the risk of paralysis of the sciatic nerve.

The fragmented fractures:

Pain is foremost often without major functional impotence (possible walking). The radiological assessment must be guided by the clinic, whether it be a tuberoscopic removal, a fragmented fracture of the iliac wing or the obturator frame in the elderly. The horizontal lines of the sacrum can be isolated and are well seen on the radiographs of profile.

Fractures of a single point of the pelvic ring, called elementary, are rare, and should be considered as such only after eliminating another interruption of the ring, if necessary by CT.

Fractures of the femur:

Upper end of the femur:

They occur mostly in the elderly, females, in a simple fall (bone fragility by osteoporosis), rarely in young people during a violent trauma (road accident).

The standard radiographic assessment is in most cases sufficient for the diagnosis of a frontal pelvis and a hip of face and profile (Arcelin surgical profile).

The trait may be sub-capital, transcervical (most common) or basicervical. The displacement is evaluated from the front according to the Garden classification (Type 1: in coxa valga, type 2: without displacement, type 3: in varus hooked, type 4: totally free head) or by comparing the two incidences. Simple cervical or pertrochanteric fractures are stable, while intra- or subtrochanteric, complex pertrochanteric or trochantero-diaphyseal fractures are unstable. The risk of necrosis of the cephalic fragment is all the more important as the displacement is marked (Garden 3 and 4).

Rarely the fractures are diagnosed more difficult on the standard images and it is the radioclinic discordance that requires the realization of a scanner.

Femoral diaphysis:

They present a significant hemorrhagic risk. The radiological assessment must be carried out after traction. It must have two orthogonal incidences and visualize the above and underlying joints.

Trauma to the knee:

Fractures of the lower extremity of the femur:

We can distinguish supracondylar metaphyseal fractures, epiphyseal condylar fractures. Radiographic diagnosis of unicondylial fractures is sometimes difficult. They require solid osteosynthesis to avoid stiffness, deaxation or osteoarthritis.

The fractures of the patella:

They are consecutive to direct shock. Transverse fractures (such as ruptures of the quadriceps tendon or patellar tendon) interrupt the extensor apparatus; they are obviously diagnostic on the profile. Sagittal fractures are less obvious on the face plate.

Fracture of the tibial plates:

These are frequent fractures that have severe functional prognosis and may compromise walking and standing. These fractures are secondary to indirect mechanisms of axial or lateral compression. All of these lesions are very often accompanied by ligamentous lesions. Medial spinotuberosal fracture with comminution of the spinal mass is the equivalent of bone deinsertion of the anterior cruciate ligament. A haemato-lipid level on the horizontal radius knee profile in the sub-quadricipital sac, marks the articular fracture. The precise anatomical assessment often involves the realization of a CT (analysis of the fragments and their displacement, the importance of the associated settlement).

Knee dislocations:

They are rare. Standard x-rays are enough to show the direction of movement. It will be necessary especially to seek a vascular complication (intimal lesion) by Doppler or arteriography even if the pulse reappear.

Knee sprains and meniscal lesions:

They are frequent. In case of clinical doubt, radiological exploration will return to the absence of fracture. The assessment of the lesions of the meniscus ligament will be carried out by the MRI in a second stage, outside the context of emergency. The notch of the external condyle, secondary to an osteochondral compaction, must evoke a lesion of the anterior cruciate. A lateral tearing of a tibial plateau evokes an associated ligamentous lesion. (Fracture of Second).

Ankle injuries:

Malleolar fractures:

The supra-ligamentous fractures are distinguished by abduction or rotation in which the tibio-fibular ligament is always broken, sub-ligamentary fractures by adduction in which the ligament remains intact. The rotation causes inter-ligament fractures.

The face, profile and 3/4 internal and external images are sufficient to make the diagnosis. The treatment is, in principle, early surgical to allow the perfect reduction.

Fractures of the tibial pestle:

They correspond to a separation or push-in mechanism. All these fractures are marginal (anterior, posterior or bi-marginal), and almost all comminutives, of difficult standard exploration. The degree of urgency is directly related to the amplitude of the displacement; it is necessary to restore the anatomy of the malleolar forceps.

Ankle sprains:

In 95% of cases, they involve the lateral collateral ligament. The balance should seek a tearing of the tip of an malleolus or an osteochondral lesion of the talian dome.

Trauma of the foot:

Slope fractures:

The talus or astragalus is a short and compact bone, of which about 60% of the surfaces are cartilaginous: in a situation intermediate between the leg and the foot, it is subjected to strong constraints. These fractures are infrequent; their severity depends on the presence of a dislocation of the tibiotarsal and / or subtalar associated with a major risk of secondary osteonecrosis. The relative rarity of these fractures must not undermine the risk of secondary osteoarthritis. Total fractures (ex: separations of the cervix and the body) are distinguished, with the risk of necrosis of a fragment, and fragment fractures in the context of a sprain.

Fractures of later processes:

These are the most common fracture fractures.

They may be associated with partial fractures of the head or with dislocations under isolated astragalus. The fracture of the posterolateral tubercle (fracture of E. Cloquet-Sheherd) is the cause of a syndrome of the posterior intersection of the ankle of clinical and radiological diagnosis often delayed.

Fractures of the lateral process of the embankment:

They often go unnoticed; the clinical symptomatology is most often confused with that of a sprain.

It must be systematically searched on the face plate with medial rotation of 10 to 15 °. It is the coronary section scanner that is the most effective examination for the persistence of a syndrome of the external intersection of the slope.

Osteochondral fractures:

They should be classified as: chondral impactions, non-displaced partial fractures, detached fractures without displacement, osteochondral fragments released into the joint, subchondral fibrous geodes surrounded by multiple sclerosis (Loomer classification).

Fractures of the calcaneus:

The most frequent fractures of the foot (60%), they account for 2% of all fractures with a clear male predominance;they can be bilateral.

These fractures usually result from a fall on the heels, resulting in calcaneus shear under the influence of the body weight transmitted by the slope and resistance to the soil transmitted by the large calcaneal tuberosity. They may be associated with lumbar vertebral compression.

The standard X-ray profile includes a retrotibial profile and incidence, which visualizes in particular the subtalar articulation and the posterior tuberosity. Extra-articular fractures are rare and of good prognosis, standard radiographs are generally sufficient. In 3/4 of the cases, fractures of the calcaneus are complex reaching the subtalar articulation, and poorly explored by the standard images, requiring a CT scan which specifies the seat and the orientation of the fracture lines; the number and type of main fragments; the displacement with respect to the sustentaculum tali. This CT also allows the study of thalamus (joint congruence); of the cortical and the search for a stretch of plantar; soft tissue (fibular tendon incarceration) and tarsal sinus analysis (interosseous ligament study).

Thalamic fractures:

Secondarily most often due to a vertical fall by double shear mechanism of the large process and axial compression of the thalamus, Duparc classifies them into five anatomopathological types of increasing gravity (according to the number of fragments), well correlated to functional prognosis.

Fractures of the beak of the large calcaneus process:

These are joint fractures which threaten the congruence of the calcaneo-cuboidal joint; they may be a source of secondary osteoarthritis and chronic pain, if an articular incongruence persists.

Fractures of sustentaculum tali:

They are often associated with a lesion of the medial collateral ligament. They pose the problem of the future of the anterior talus articulation.

Extra-articular fractures

These are extrathalamic particle fractures with a predominant interest in the large tuberosity of the calcaneus. They generally consolidate under orthopedic treatment.

Fracture of the navicular bone:

There are three types of fractures.

The cortical evulsions, sit on the dorsal surface and represent 50% of the lesions of the scaphoid.

Fractures of the scaphoid body; the total fractures with horizontal lines with enucleation of the upper fragment present a high risk of necrosis.

Fractures of the internal tubercle, in relation to the insertion of the posterior tibial tendon. This fracture may present differential diagnosis problems with accessory scaphoid bone present in 10% of the population and bilateral in 66% of the subjects.

Tibio-tarsal and subtalateral changes:

They represent 15% of the slope pathology and 1% of all dislocations. They are rarely isolated, most often associated with fracture of the talus or calcaneus with talo-calcaneal incongruence. The risk of cutaneous necrosis requires a rapid reduction.

Trauma of the forefoot:

Tartso-metatarsal dislocations of the Lisfranc joint:

These are the most common foot dislocations, related to a trauma in forced plantar flexion associated with a rotation.They are readily associated with fractures such as the base of the 2nd metatarsal, 1st cuneiform or cuboid.

The radiographic assessment includes face shots,   profile and 3/4 of the forefoot.

Groulier and Pinaud proposed a simple classification:

Total or homolateral dislocation: all metatarsals are moved in the same direction; Divergent total dislocation: medial displacement of the first metatarsal (column) and lateral of the four lateral metatarsals (palette); partial dislocation (isolated displacement of one or two metatarsals relative to the whole). These fractures may go unnoticed in a polytrauma context.

They require a perfect anatomical reduction (closed or bloody) because the risk of secondary osteoarthritis is great. In case of major comminution, an arthrodesis can be proposed.

Metatarsal fractures:

They should be searched on the frontal and 3/4 frontal fractures, particularly fractures from the base of the 5th metatarsal whose fragment can be attracted at a distance by the tendon of the short fibular and require surgical treatment .

Muscle and tendon trauma:

Muscle trauma mainly affects athletes during a sudden acceleration or in an inappropriate effort. Ultrasound is the reference examination which shows a localized disorganization of the muscle fibers associated with a fluid suffusion against the fascias and aponeuroses as of the second day of evolution.

It may be negative in the first two days due to the hyper-echogenicity of the hematoma at the initial stage. She appreciates the volume of the hematoma and the degree of severity of the muscular lesion.

Stage 0 is a simple contracture. Stage 1 corresponds to an elongation involving some muscle fibers. Stage 2 is a breakdown with lesion affecting less than half the thickness of the muscle; the partial ruptures are poorly visible (hypoechogenicity of the normal muscle) and we must seek the interruption of the interfascicular echogenic conjunctivo-adipose partitions that are broken at the same level as the fibers.

Stage 3 achieves a complete break with possible muscle retraction. The ball-like appearance of the segment broken within a sero-hematic collection constitutes the classic image by “beating the bell”. The complete rupture is confirmed by the dynamic test which reproduces on the screen the deformations visible to the inspection.

MRI will be reserved for clinical or ultrasound to provide a very accurate assessment of the lesions and their stage of scarring or to eliminate an underlying tumor process.

Arterial trauma:

The severity of traumatic vascular lesions is more often related to arterial lesions than to venous lesions.

These arterial lesions are the cause of serious ischemic or haemorrhagic events.

In the emergency room, signs of distal ischemia or haemorrhage should be explored, first and foremost, by Doppler ultrasound, which may demonstrate the persistence of clinically distal distal vasculature or hematoma. Arteriography is necessary for the exact assessment of the lesions, it shows the type of lesion (total section, incomplete rupture respecting the adventitia, the residual network, the possible existence of an arteriovenous fistula). It can participate in hemostasis by embolization. If an arterial lesion is suspected the standard images will always be realized.

In case of open osteo-articular lesion with sign of ischemia, after surgical exploration, the arteriography will be carried out in a second time to check the repair of the arterial lesions. In case of a closed osteoarticular lesion with signs of ischemia, compression or arterial rupture should be evoked if the osteo-articular lesions are displaced. The Doppler will check the elimination of ischemia after orthopedic reduction; it is only in the absence of efficacy of the orthopedic treatment that the arteriography is indicated to seek either an arterial lesion proper or a compression by the hematoma. In front of a distal ischaemia with wound of the soft parts, without osteo-articular lesion (lesion by vulnerable agent or bullet), exploration of the vascular wound is in peroperative rule. Arteriography will be considered only in a hemodynamically stable patient and sometimes indicated in preoperative in case of clinical doubt about an arterial lesion.

Conclusion:

In general, standard radiographic exploration is usually sufficient to locate a focus of diaphyseal fracture, to specify its type and to appreciate its displacement.

Complementary CT scans with 2D or 3D reformatting must be performed during joint fractures: tibial plates, rear foot.

They analyze the different articular fragments and their displacements, the articular congruence; they specify the presence of any free bone scales in intra-articular situation. Postoperatively, CT is also useful in assessing the realignment of bone fragments, the persistence of intra-articular fragments, and the correct positioning of the osteosynthesis material.

The existence of extra-osseous complications occurs first and foremost in emergency management. Vascular complications, whether distal ischemia per wound or arterial spasm, or syndrome of the logs associated with hematoma and post-traumatic edema, must condition the initial gesture. Simple compressive phenomena can be retroceded after reduction of the fracture focus. A discharge aponeurotomy is sometimes necessary in an emergency.

Nervous complications should be systematically investigated; they are oriented by the seat of the fracture; a fracture of the middle third of the humeral shaft (10 to 20% of the cases).

Skin complications are most often the result of direct impact fracture, from dermabrasion to loss of cutaneous substance (classification of J Cauchoix and J. Duparc: Type 1, limited skin opening, Type II, Contused wound with subcutaneous detachment, type III, loss of cutaneous substance).

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