Injuries to bones and joints of lower limb

Question 1

Define fracture

Answer 1

a breach of the integrity of part of the whole of a bone

Question 2

define subluxation

Answer 2

partial separation of the articular surfaces of a joint e.g. shoulder joint, subluxation would be capsule stretching, humeral head coming apart slightly but goes back again.

Question 3

define dislocation

Answer 3

complete separation of the articular surfaces of a joint

Question 4

define fracture dislocation

Answer 4

severe injury in which fracture and dislocation take place simultaneously, involving one or more of the articular surfaces of a joint. Requires surgical replacement of the fractured articular surfaces.

Question 5

define a sprain

Answer 5

sprain is where there is stretching or tearing of the ligaments or joint capsule causing pain but is insufficient to produce subluxation or dislocation

Question 6

What is required to fracture a bone?

Answer 6

1) either weakened bone or 2) excessive force/ energy

Normal bone plus normal force –> no fracture

Normal bone plus excessive force –> fracture

Weakened bone + normal force –> fracture

Question 7

What can cause weakened bones?

Answer 7

Osteoporosis –> increased bone resorption leading to weakened bone

Metastatic cancers –> most common form of bone cancers are actually secondary cancers that are metastases from other primary tumours, weakens bone

Genetic conditions e.g. osteogenesis imperfecta –> genetic defect in collagen genes

Question 8

What are the clinical signs and symptoms of a fracture?

Answer 8

Most obvious sign = deformity (outstanding feature)

Abnormal movement (outstanding feature)

Crepitus

Others: (non specific) pain, tenderness, bruising and swelling

Question 9

Fractures and pain

Answer 9

Bones do not have sensory nerves of any kind (some in periosteum but main substance of bone no nerves).

Can affect the nerves around it, and bleeding causes pain. Blood escapes into surrounding tissues, into the muscles and causes pain.

Muscle compartments held together by tight fascia, when a fracture occurs and there is a bleed there is an increasing pressure within the fascial space -> pain.

Question 10

What type of fracture communicates with the outside world? How may they occur?

Answer 10

1) Compound fracture –> fracture in which broken bone pierces the sin causing a risk of infection.

Compound fractures can come from within (i.e broken bone pushes out of the skin) or from without where there is an external force that breaks the bone and lacerates the skin (i.e motorbike accident).

Question 11

What is a complicated fracture?

Answer 11

A complicated fracture is where the structures surrounding the fracture are injured.

There may be damage to surrounding veins/ arteries/ nerves/ injury to the periosteum.

E.g. Skull fracture and brain injury, vertebral column fracture and spinal cord injury, rib fracture and pneumothorax/ damage to other tissues (spleen).

Question 12

What is delayed union?

Answer 12

Delayed union generally define as failure to reach bony union by 6 months post injury, and includes any bone fracture that is taking longer than expected to heal.

Normally bones heal within 6 weeks- 6 months.

Callus normally forms which indicates there is the potential for healing but full healing hasnt occurred yet.

Question 13

What is non union?

Answer 13

non union is an arrest in the fracture repair process, no healing process taking place at all.

Question 14

What is mal union?

Answer 14

Malunion is where the bone joins in the wrong alignment.

Question 15

How do you diagnose a fracture?

Answer 15

1) History and examination
2) Xray
3) CT - to show the different planes of an injury
4) MRI - to show soft tissue damage, often useful if the articular cartilage is thought to be involved and to see the density of the bone in cases of suspected avascular necrosis. Can also detect any fluid within the joint.
5) ultrasound - if unable to detect the fracture on xray but highly suspected, often in children’s fractures
6) Bone scan

Question 16

What are three key complications of pelvic fractures?

Answer 16

1) Blood loss - can be fatal. Arteries and veins run close to the bone. Veins cannot contract due to the lack of elastic fibres and the patient will bleed rapidly (e.g. femoral vein). Arteries can contract and stop the bleeding.
2) Abdominal injury - certain regions of the colon are adherent to the pelvis and can be injured. Significantly damaged is the bladder, it is retropubic and fractures here can often damage the bladder. In men the urethra can be damaged as it passes under the pubic symphysis.
3) Nerve injury - some nerves are adherent to the bone, the sciatic nerve is closely adhered to the sacral bone, fractures of the sacrum and of the sacroiliac joint can damage the nerve.

Question 17

How can the ilium become damaged?

How can Pubic fractures occur?

Answer 17

• Ilium most commonly damaged due to high energy trauma to the lateral portion of the hip bone i.e fall, car accident
• Pubic rim fractures most often occur in the elderly and osteoporotic. When weight bearing there will be pain as they put their feet on the ground.

Question 18

What is an open book fracture?

Answer 18

Open book fracture is a term used to describe any fracture that significantly disrupts the pelvic ring. Injuries combine anterior pubic injury with a widening of the pubic symphysis and a posterior pelvice fracture or ligamentous injury (often sacroiliac joint).

Question 19

What is the significance of the pelvic ring?

Answer 19

The pelvic ring must be maintained in order for you to weight bear.

Both the pubic symphysis and the sacroiliac joint must remain intact for you to weight bear, otherwise the patient will be unable to walk and there will be pain.

Question 20

Acetabular fracture:

Intra- articular fracture:

what is dislodged?

What two regions can this occur in?

What structure may be damaged due to this type of fracture?

Answer 20

• Intraarticular fracture –> dislogde the articular surfaces, have to be restored to prevent the occurence of arthritis
• Occurs centrally: Blow hits the femur from the side, can knock the femoral head through the inside wall of the pelvis
• Landing on your feet from a height can push the femur head vertically and hits the roof of the acetabulum (the weight bearing area).
• Blow to the femoral head against the acetabulum will damage the articular cartilage and there may be death to the articular cartilage because of it.

Question 21

Fractures of the neck of the femur:

majority of causes

Forces acting on it

Risk of this fracture and blood supply to the femoral neck and head

Answer 21

Majority of fractures of the neck of the femur are caused by osteoporosis (weakened bone)

Often after a fall or may occur spontaneously –> low energy injury

Or due to high energy injuries i.e RTA affecting ipsilateral side.

Forces acting on the neck of the femur, as they are transmitted up the femur shaft and forces transmitted down the bony pelvis.

Risk of avascular necrosis –> blood supply from medial and lateral circumflex arteries that come from the profunda femoris, they pass up into the neck, into the periosteum to supply the femoral neck and head. The blood supply of children is even more at risk as there is a growth plate between the femoral head and neck and the shaft.

Question 22

What are NOF hip fractures divided into?

Characteristic of neck of femur fracture

Answer 22

• Divided into intracapsular (within the capsule) and extracapsular (outside)
• Capsule attached at the base of the neck and within the acetabulum.

Intracapsular: Most important for blood supply and risk of avascular necrosis. Divided into:

• Subcapital (through the junction of the head and neck)
• Transcervical (through base of femoral neck)

Extracapsular: Still able to maintain blood supply to head and neck, no avascular necrosis with those.

• Intertrochanteric (between two trochanters)
• subtrochanteric/ basal fracture (5 cm ditsal to lesser trochanter).

Presentation: Leg characteristically shortened (psoas major shortening bone) and externally rotated (gluteal muscles rotate it outward).

Question 23

What is the treatment for intracapsular fractures?

Answer 23

Initial management: stabilise the patient, ensure adequate analgesia, surgery.

Subcapital fratures:Hip hemiarthroplasty –> replacement of the femoral head and neck via a femoral component fixed in the proximal femur, there are problems with this, the metal can erode the bone.

In young and more active patient total hip replacement (total arthroplasty) where the femur head, neck and acetabular surface are replaced, is often the answer.

Question 24

What is the treatment for an extracapsular fracture?

Answer 24

Screw in the neck to the head that is then fixed with a plate. Imparts mechanical stability across the fracture.

Question 25

What should you be aware of in a younger patient with a NOF

Answer 25

The younger the patient, the greater the risk of the blood supply and the greater the risk of avascular necrosis.

This is because it takes a high energy/ impact trauma to cause NOF in a younger patient, meaning the damage done is likely to be severe.

Question 26

Traumatic hip dislocation: Posterior dislocation

What type of trauma does it require and why?

What is the management?

What is a common complication of this type of injury?

Answer 26

• Traumatic hip dislocations require high energy/ force trauma, i.e. RTA that causes the knee and hip to be flexed, the head of femur to be forced posteriorly. Can be associated with a fracture of the posterior acetabulum.
• Difficult to dislocate an ordinary hip joint due to the strength of the capsule and associated ligaments and the contour of the femoral head within the acetabulum.
• Must reduce this dislocation and restore the articulation of the femur and the acetabulum within 6 hours otherwise there can be death of the cartilage (chondrolysis).
• As the femur is dislocated posteriorly the sciatic nerve is behind, so this injury is not uncommon.

Question 27

Femur shaft fracture:

Common surgical management

Answer 27

• Intramedullary nail down the central canal of the femur, screws placed above and below the fracture to hold the leg in the correct alignment whilst the bone heals.
• patient stable and able to walk about within days

Question 28

Patella fracture:

How do they occur?

What types of patella fracture are there?

How are they treated?

Answer 28

• Patella fracture typically from a fall or blow to front of the knee.
• Patella fractures can be:
  
  • stable (where the patella is non displaced but broken ends separated by a millimeter or two)
  • Displaced (broken bones separated, upper portion pulled up by the femoral tendon and lower part pulled down by the femoral ligament)
  • Comminuted –> boen shattered into three or more pieces
  • Open fracture –> patella breaks through the skin
• Complication: Bleeding into the knee joint often damages the cartilage and needs to be cleaned out.
• Treatment of tranverse fracture often via Figure of 8 wiring that fixes patella pieces together in the centre of the knee.
• In comminuted fractures the patella pieces are too small to be fixed back into place, treated by removal of the patella called patellectomy.

Question 29

Tibial plateau fracture:

What is it?

How does it occur?

Complications?

Answer 29

• Tibial plateau fracture is a serious injury invlving a break in the proximal tibia that involved the knee joint. The tibial plateau has a medial and lateral weightbearing portion (condyles) and intercondylar eminence which is non articular and non weightbearing.
• Cause of the trauma is normally high energy such as due to a fall or RTA, due to excessive varus (inward angulation) or excessive valgus (outward angulation) forces.
• Complications:
  
  • from inappropriate treatment include posttraumatic arthritis.
  • There is intraarticular, soft tissue damage within the knee.
  • Structures at risk are the common fibular nerve and tibial nerve, popliteal vessels. (vascular and nerve injury)
  • Associated with amputation if the blood vessels arent restored in time.
  • Blood within the knee joint = haemoarthrosis can lead to death of cartilage (chondrolysis).
  • meniscal tears and ACL injury
  • Compartment syndrome

Question 30

Menisci injury:

Menisci: what are they, what is their function?

Ability to self repair?

Cause of meniscal tears?

how will the joint appear?

how are meniscal tears fixed?

Answer 30

Top of tibia are the menisci, C shaped fibrocartialge that act as 1) shock absorbers of the knee joint 2) increase the articulating surface area (distribute force across the surface of the tibia).

Menisci are avascular and therefore cannot self repair.

Medial meniscus is more circular than the lateral and attached to the medial collateral ligament.

Mechanism of injury: Either trauma related or degenerative disease (as in older patients).

In traumatic tears mechanism requires rotation of the femur on the fixed tibia (with the foot fixed on the ground).

Joint will appear with limited knee flexion or extension, joint line tenderness and joint effusion.

Smaller tears treated with RICE, larger tears treated with arthroscopic surgery (keyhole surgery).

Question 31

Cruciate ligaments:

Anterior: normal role, mechanism of injury, clinical tests, treatment

Posterior: normal role, mechanism of injury, treatment

Answer 31

Cruciate ligament injuries: ACL

ACL is a common injury to the knee joint, primary role to limit anterior translation of the tibia relative to the femur. Mechanism of injury typically extensive force on the knee joint, often in athelets that twist the knee whilst weight bearing.

Presents with rapid joint swelling and significant pain. MRI scan to confirm is gold standard.

Tests: Anterior drawer test and Lachman’s test

Anterior drawer test –> knee flexed to 90 degrees

Lachman’s tests –> knee 30 degrees flexion, hand stabilises the femur, other hand pulls the tibia foward to assess anterior movement.

Treatment:

RICE then either conservative or surgical

Conservative –> rehab using strength training of quadriceps to stabilise knee, and splint

Surgical –> often use the semitendinosus tendon or artifical tendon to fix the ACL. Patient requires prehabiliation before the surgery, with physiotherapy.

Posterior Cruciate ligament tear:

Less common injury. Restains posterior tibial translation. Typically occurs with high energy trauma such as direct flow to proximal tibia during RTA. Often treated conservatively with knee brace and physio.

Question 32

Tibial shaft fractures

How can they occur?

What types of tibial shaft fracture are there?

Complications?

Treatment?

Answer 32

• Tibial shaft fractures most common fracture of long bone in the body
• Typically requires major force to cause injury e..g RTA, due to direct trauma (transverse fracture) or rotational strain (spiral fracture)
• Transverse fracture = break is straight horizontal line going across the tibial shaft
• Oblique = angled fracture
• Spiral fracture = caused by twisting force, fracture line encircles shaft of the tibia
• Complications:
  
  • Interosseous membrane can also be damaged all the way to the top
  • acute compartment syndrome, pressure in the muscular compartment rises leading to hypoxia and necrosis.
• Treatment:
  
  • Intramedullar nailing with metal rod inserted into canal of the tibia, fixed at either end by scews. (not ideal for childrens and adolscent)
  • Can be fixed externally, traditionally with a plaster or via external fixation.
  • External fixation: metal screws above and below fracture site, attached to a bar outside the skin

Question 33

Important complication of fractures?

What is the pathophysiology?

How will the patient present?

Answer 33

Compartment syndrome: (Acute = after injury, chronic after athletic exertion)

• Critical pressure increase within confined compartmental space
• decline in perfusion pressure
• leads to ischaema and necrosis of muscles in that region, permanent disability of the affected region without treatment, can lead to multi organ failure and loss of limb
• Muscle enclosed in fascial compartment, when there is trauma and inflammation the pressure increases and compromises low pressure venous return , leading to further increase in intracompartmental pressure.
• Capillaries become compressed, arterial supply ceases –> ischaemia and infarction.
• Clinical features: Pain disproportionate to the injury or is worsening despite treatment.
  
  • ​Paraesthesia, generalised musclar tenderness and swelling.
  • 5 p’s –> pain, pallor, perishingly cold, paralysis, pulselessness

Question 34

Treatment of compartment syndrome?

Answer 34

• Limb kept at neutral level
• improve oxygen delivery with high flow oxygen
• analgesia
• Emergency open fasciotomy, skin incision left open to monitored 24-48 hours

Question 35

What results from dysfunction in the anterior leg compartment?

Answer 35

• Footdrop:
  
  • indicates paralysis of muscles in anterior comaprtment of the leg
  • commonly seen due to damage of the common fibular nerve (from which deep fibular nerve arises that innervates anterior compartment of the leg).
  • Unopposed pull of plantarflexor muscles produces permanent plantarflexion
  • limb drags on the gound
  • patients present with high stepping gait or eversion flick

Question 36

Ankle fractures:

Where can they occur? What is the ankle mortice?

What is intracapsular? What is extracapsular?

What is the difference between intraarticular and extraarticular ankle fractures?

what is a fracture of the calcaneus known as?

What are ankle fractures often accompanied by?

What is the treatment?

Answer 36

• Can occur at the medial and lateral malleoli or the ankle mortice
• Ankle mortice formed of the tibia, fibula and the talus
• Intracapuslar fracure occurs within the joint capsule, extracapsular outside.
• Intra articular fractures of the ankle are known as Pilon fractures.
• Intraarticular fractures occur at the subtalar joint between the talus and the calcaneus.
• Fracture of the calcaneus is known as the os calcis fracture.
• Extraarticular fractures are termed ankle fractures.
• Often ankle fractures accompanied by soft tissue injury:
  
  • skin lesions
  • vascular compromise
  • worse in diabetics and smokers
• Treatment by restoring the articular surface.
• RICE to allow soft tissue swelling to decrease
• often treated in a plaster, however if the bones are disrupted significantly by screws and plates.

Question 37

Achilles/ Calcaneal tendon rupture:

Answer 37

• Often in patients that are unfit and have a sudden increase in exercise frequency, or due to overuse to the tendon leading to achilles tendonitis.
• Tendon rupture presents as sudden onset severe pain and popping sound
• Marked loss of power of ankle plantarflexion
• Simmonds test:
  
  • patient prone on table, with ankles hanging off the edge, squeeze the calf muscle and the ankle shoud move, foot should plantaflex. In rupture, the ankle will not move.
  • Ultrasound test to image
• Treatment:
  
  • conservative or operative, physiotherapy

Question 38

Lisfranc injury:

What is it?

What is it associated with?

Answer 38

• Amputation of the tarsometatarsal joint, particularly occuring between the second metatarsal bone and the tarsal bones
• If the second joint becomes dislodged then the entire joint can move about
• Associated with soft tissue injury and vascular damage