pelvis and lower limb trauma

Question 1

what is the mechanism of injury of acetabulum fractures?

Answer 1

high energy injuries in the younger patients but can be low energy in the older patients

Question 2

what is the best investigation for acetabulum fractures?

Answer 2

difficult to determine on plain X-rays (oblique views may help) and CT scans help to determine the pattern of the fracture and are essential for surgical planning

Question 3

what is the management of undisplaced acetabulum fractures?

Answer 3

undisplaced fractures/small wall fractures - conservatively

Question 4

what is the management of unstable/displaced fractures?

Answer 4

anatomic reduction and rigid fixation in the younger patients to reduce the risk of post traumatic OA

older patients may be treated with total hip replacement - either early (with an uncemented cup and screws) or delayed

Question 5

what is the risk in intracapsular hip fractures?

Answer 5

the arterial supply of the femoral head can be disrupted and there is risk of avascular necrosis of the femoral head and non-union of the fracture

Question 6

what is the management of intracapsular hip fractures?

Answer 6

replacement of the femoral head - heme-arthroplasty (replacing the femoral head alone) or total hip replacement (replacing the acetabulum as well as the femoral head)

Question 7

what is the risk of total hip replacement?

Answer 7

higher risk of dislocation (particularly in the cognitively impaired) but can give better function

Question 8

what type of arthroplasty is reserved for the higher functioning hip fracture?

Answer 8

total hip replacement

Question 9

what type of arthroplasty is preferred for those with restricted mobility and cognitively impaired patient?

Answer 9

semi-arthroplasty

Question 10

why do extra capsular fractures not cause avascular necrosis?

Answer 10

because blood supply is not affected and they have a high union rate

Question 11

how should extra capsular hip fractures be managed?

Answer 11

internal fixation keeping the patient’s own natural hip joint

such fixation can include compression or dynamic hip screw

Question 12

what is fixation with dynamic hip screw?

Answer 12

this fixation consists of a large screw inserted into the femoral head across the fracture line and the a plate which has a barrel which engages with the lateral end of the screw and is fixed to the femoral shaft
as the patient weight bears the screw is allowed to slide in the barrel of the plate, which results in compression at the fracture site which promotes fracture healing

Question 13

how do extracapsular fractures heal?

Answer 13

heals in a shortened position

Question 14

how do femoral shaft fractures occur?

Answer 14

high energy injuries and there is a substantial risk of concomitant fracture elsewhere and stress fractures can also occur

Question 15

when can a stress femoral fracture occur?

Answer 15

osteoporotic bone, metastatic disease, patients with Paget’s disease and paradoxically with long term bisphosphonate use for osteoporosis

Question 16

what can occur with femoral shaft fractures?

Answer 16

substantial blood loss up to 1.5litres. Fat from he medullary canal can enter the damaged venous system resulting in fat embolism with confusion, hypoxia and risk of ARDS

Question 17

what is the initial management of femoral shaft fractures?

Answer 17

after initial resuscitation includes optimizing analgesia with a femoral nerve block and application of a Thomas splint which stabilizes the fracture minimizing further blood loss and fat embolism.

Question 18

what is the definitive management of a femoral shaft fracture?

Answer 18

closed reduction and stabilization with an intramedullary nail however minimally invasive plate fixation with minimal disruption to the fracture site blood supply can also be used

Question 19

how can knee dislocations occur?

Answer 19

in high energy injuries or with severe hyperextension and/or rotational forces with a sporting injury

Question 20

what can occur with knee dislocations?

Answer 20

it is a surgical emergency with a high incidence of vascular injury (intimal tears, vascular occlusion, complete transection), nerve injury and compartment syndrome

Question 21

how should obvious knee dislocations be managed?

Answer 21

reduced urgently with thorough neuromuscular assessment and vascular surgery referral if any doubt with further investigation (Doppler, duplex scan or angiogram) and revascularization (endovascular procedures or bypass) as required

Question 22

how should very unstable knee dislocations be treated?

Answer 22

external fixator may be applied, multi-ligament reconstruction is typically required as in order for the knee to dislocate, multiple ligaments are usually torn

Question 23

what present with knee injuries usually?

Answer 23

gross instability (particularly PCL ad LCL injuries from hyperextension and various) may actually have been momentary true knee dislocations with spontaneous reduction so careful attention should be paid to neuromuscular status

Question 24

how common are patellar dislocations?

Answer 24

relatively common

Question 25

how do lateral dislocations of the patellar occur?

Answer 25

due to a direct blow (e.g. clash of knees at port) or a contraction of the quadriceps with a rotational force with the patella not engaged in the trochlea (less than about 30 degree flexed)

Question 26

what happens in a patellar dislocation?

Answer 26

it may remain dislocated requiring manipulation for reduction or more commonly may spontaneously reduce when the knee is straightened

Question 27

subluxations of the patella can also occur?

Answer 27

without frank dislocation

Question 28

who are patellar dislocations and subluxations more common in?

Answer 28

adolescents, particularly females

Question 29

what are the pre-disposing factors of patellar dislocations?

Answer 29

generalized ligamentous laxity valgus alignment of the knee rotational malalignment (including femoral neck anteversion) and a shallow trochlear groove

Question 30

where do patients have tenderness in patellar dislocations?

Answer 30

over the medial retinaculum (where the medial patellofemoral ligament is torn) and may have haemarthrosis from impaction of the medial patellar facet on the outer aspect of the lateral femoral condyle

Question 31

how can osteochondral fractures occur?

Answer 31

with sheared off/detached fragments occasionally requiring retrieval or fixation depending on their size and amount of bone on the detached fragment

Question 32

what percent of those with patellar dislocation will experience a further dislocation?

Answer 32

10% and 50% of those will have multiple recurrent dislocations

Question 33

what helps further dislocations?

Answer 33

temporary splintage followed by physiotherapy (to strengthen the vests medals) can help prevent further dislocations and many adolescent patients stabilize as they get older occasionally surgical stabilization with either a bony procedure for Malignment or a soft tissue (MPFL) reconstruction is required

Question 34

how do tibial plateau fractures occur?

Answer 34

either high energy injuries in the younger patient or low energy in osteoporotic bone

Question 35

what type of fracture are proximal tibial fractures?

Answer 35

They are intra‐articular fractures with either a split in the bone, a depression of the articular surface or a combination of both.

Question 36

how are proximal tibial fractures classified?

Answer 36

according to the Schatzker system

Question 37

what are associated with high energy injuries proximal tibial fractures?

Answer 37

neuromuscular injury or compartment syndrome

Question 38

what is required to combat the risk of stiffness and post-traumatic OA in proximal tibial fractures?

Answer 38

surgery | CT scans are useful to plan surgical fixation

Question 39

what does a values stress injury to the knee cause?

Answer 39

a lateral plateau fracture with failure of the MCL and possibly ACL with increasing force

Question 40

a direct blow from a car bumper may also cause?

Answer 40

proximal fibular fracture and injury to the common perineal nerve with foot drop (due to loss of power to tibias anterior

Question 41

a varus injury to the knee results in?

Answer 41

a medial plateau fracture (less common) with potential for LCL rupture and stretch injury to the common perineal nerve

Question 42

what is the management of proximal tibial fractures?

Answer 42

plates and screws are usually used for fixation. once a depressed fracture has been elevated, a void in the bone is left requiring bone grafting (usually morsellised packed cancellous autograft from the iliac crest) to provide support

Question 43

how do you treat high energy proximal tibial fractures?

Answer 43

often substantial soft tissue swelling and temporary external fixator spanning the joint may be required for initial stability and to allow the swelling to resolve before definitive open reduction and internal fixation some surgeons use external fixation for the definitive management of these injuries using a ring fixator and fine wires under tension to hold fracture fragments

Question 44

why is total knee replacement required?

Answer 44

despite efforts to restore the articular surface, results of surgery are often disappointing and patients often require subsequent total knee replacement

Question 45

what is a lisfranc fracture?

Answer 45

This is an uncommon but often overlooked injury where a fracture of the base of the 2nd metatarsal is associated with dislocation of the base of the 2nd metatarsal with or without dislocation of the other metatarsals at the tarso‐metatarsal joints.

Question 46

what occurs in the lisfranc fracture?

Answer 46

the ligament from the medial cuneiform to the base of the 2nd metatarsal no longer holds the metatarsal in joint

Question 47

what imaging is used to see a lisfranc injury?

Answer 47

The fracture may only be a small flake fracture which can be easily missed and the dislocation can be difficult to appreciate on standard Xrays. A CT scan is required if there is any doubt.

Question 48

what is the patient presentation of a lisfranc fractures?

Answer 48

grossly swollen, bruised foot upon which they're unable to weight bear. be wary of normal looking X-rays

Question 49

what is the management of lisfranc injuries?

Answer 49

fairly high risk of pain and disability and therefore to reduce this risk closed/open reduction with fixation using screws is recommended

Question 50

which is a common site for metatarsal fractures?

Answer 50

fractures at the base of the 5th metatarsal

Question 51

what is the mechanism of injury for a 5th metatarsal fracture?

Answer 51

inversion injury with an avulsion fracture at the insertion of the peroneus braves tendon

Question 52

what is the management of 5th metatarsal fractures?

Answer 52

These heal predictably and require a walking cast, supportive bandage or wearing of a stout boot for 4‐6 weeks. Even with those which fail to achieve bony union, many have a stable fibrous non‐union which is usually asymptomatic.

Question 53

why is the 1st metatarsal fracture uncommon?

Answer 53

(due to its thickness and strength) but such is the importance of the first ray to foot function that fractures of the first metatarsal are usually fixed.

Question 54

what is the management of the lesser metatarsals?

Answer 54

The lesser metatarsals are commonly fractured, often with multiple fractures. With minimal displacement these may be treated conservatively with a cast. Multiple displaced fractures may be stabilized with K‐wires to reduce the risk of chronic pain.

Question 55

which metatarsal is a common site for a stress fracture?

Answer 55

2nd metatarsal

Question 56

how can fractures of the 2nd metatarsal occur?

Answer 56

spontaneously or after a period of increased exercise/activity

Question 57

what is the management of 2nd metatarsal fractures?

Answer 57

The fracture may not be visible on plain x‐ray until a healing / callus response has started (can take several weeks). Bone scan may aid in the diagnosis and treatment is with a cast until the pain subsides.

Question 58

what is the management of toe fractures?

Answer 58

Toe fractures rarely require anything other than protection in a stout boot.

Question 59

how do you manage intra-articular fractures of the base of the proximal phalanx of the hallux?

Answer 59

may benefit from reduction and fixation if the fragment(s) are sizeable. Open fractures require debridement and may be stabilized with a wires.

Question 60

how are toe dislocations treated?

Answer 60

Dislocations are treated with closed reduction and either neighbor strapping or wiring.

Question 61

how do tibial shaft fractures occur?

Answer 61

indirect force and either bending (transverse fracture) or rotational energy (spiral fracture), compressive force from deceleration (oblique fracture), a combination of these forces or from high energy injuries (comminuted fracture).

Question 62

are open fractures of the tibial shaft common?

Answer 62

no due to the tibial shaft being subcutaneous

Question 63

what are the most commonest causes of compartment syndrome?

Answer 63

tibial fractures (particularly the anterior compartment of the leg)

Question 64

what is the non-operative treatment for tibial shaft fractures?

Answer 64

Up to 50% displacement and 5° of angulation in any plane can be accepted with conservative management in an above knee cast. Any internal rotation of the distal fragment is poorly tolerated. The position may be difficult to control in a cast with frequent cast changes and check xrays required. If the fibula is not fractured, the tibia often drifts into varus whilst if the fibula is also fractured valgus alignment is more common.

Question 65

what is the operative treatment of femoral shaft fractures?

Answer 65

internal fixation controls the position of the fracture and removes the need for a cast with the benefits of early joint motion and a potentially quicker rehabilitation

Question 66

what is the slowest healing bone of the body?

Answer 66

he tibia is one of the slowest healing bones in the body with average time to union of around 16 weeks and can take up to a year to heal.

Question 67

how are comminuted fractures of the tibial shaft treated?

Answer 67

Comminuted fractures are highly unstable and generally require surgical stabilization.

Question 68

how are open fractures of the tibial shaft managed?

Answer 68

Open fractures require surgical stabilization as previously discussed and plastic surgical assistance may be required to ensure adequate skin coverage.

Question 69

how do you treat compartment syndrome of tibial shaft fractures?

Answer 69

urgent fasciotomies and surgical stabilization of the fracture ORIF with plates and screws gives rigid stability but dissection down to the fracture site further reduces the peristeal blood supply to the fracture site and may risk non‐union.

Question 70

what is the commonest method of surgical stabilization of the tibial shaft fracture?

Answer 70

intramedullary nailing and this promotes secondary bone healing with less disruption of the periosteal blood supply to the fracture site the nail is inserted behind the patellar tendon and around 25% of patients suffer significant anterior knee pain so it is vital to discuss this with patients pre-operatively; especially those who have an occupation that involves kneeling External fixation is favoured by some but problems can occur with pin site infection and/or loosening.

Question 71

how are non-unions of the tibial shaft fracture treated?

Answer 71

Non unions may require bone grafting or special circular frames which can be adjusted to alter angulation, rotation or length, can give compression at the fracture site to promote healing and can form new bone from distraction osteogenesis.

Question 72

what criteria is used to identify suspected ankle fractures?

Answer 72

the Ottawa criteria: Any severe localized tenderness (known as bony tenderness) of the distal tibia or fibula or inability to weight bear for four steps merits an xray.

Question 73

what needs to be made in ankle fractures?

Answer 73

With ankle fractures a distinction needs to be made between stable and unstable fractures.

Question 74

how are isolated distal fibular fractures managed?

Answer 74

Isolated distal fibular fractures with no medial fracture or rupture of the deltoid ligament are stable and are common and stable. Treatment is with a walking cast or splint for around 6 weeks.

Question 75

how are distal fibular fractures with rupture of the deltoid ligament managed?

Answer 75

unstable and usually undergo ORIF (with plates and screws). Rupture of the deltoid ligament is suspected by bruising and tenderness medially.

Question 76

how do you know the deltoid ligament is ruptured?

Answer 76

If there is any talar shift ocurring on a mortise AP view xray (with the foot slightly internally rotated) where there is asymmetric increased space around the talus within the ankle mortise (a mortise is a rectangular recess like in a mortise lock) or talar tilt with the talus and tibial plafond being non parallel, then by definition the deltoid ligament must be ruptured if there is no medial malleolar fracture.

Question 77

what is the risk of post-traumatic OA in ankle fractures?

Answer 77

nkle joint contact pressures greatly increase with even 1mm of talar shift with subsequent risk of post traumatic OA. Therefore, anatomic reduction and rigid internal fixation is required to minimize this risk with any talar shift. Gross talar shift results in a fracture‐dislocation (rather than a fracture‐subluxation).

Question 78

what is the treatment of bimalleolar fractures?

Answer 78

Bimalleolar fractures (fracture to both the medial and lateral malleoli) are unstable and usually undergo ORIF.

Question 79

how do you manage ankle fractures with substantial soft swelling and fracture blisters?

Answer 79

Ankle fractures can be associated with substantial soft tissue swelling and fracture blisters. ORIF may be delayed by 1‐2 weeks to allow the soft tissues to settle and reduced the risk of wound healing problems and infection.