MSK week 5 Flashcards
When should surgical management be considered?
When appropriate conservative measures have failed to control the condition.
Name the four surgical strategies for management of an arthritic joint?
Arthroplasty/joint replacement
Excision or resection arthroplasty
Arthrodesis
Osteotomy
What does arthroplasty mean?
Reshaping of the joint.
Replacing half a joint is known as
Hemiarthroplasty
Why do joint replacements ultimately fail?
Loosening of components (wear particles produce an inflammatory response).
What is a psuedotumour?
Metal particles from a joint replacement causing an inflammatory granuloma which can cause muscle and bone necrosis.
What is osteolysis?
Polyethylene particles causing an inflammatory response in bone with subsequent bone reabsorption
A complication of joint replacement surgery is deep infection- how is it managed?
If caught early (first 2-3 weeks)- wash out of the joint, debridement and parenteral antibiotics for 6 weeks should suffice.
If caught after 3 weeks- bacteria form a biofilm which prevents the patients immune system from getting to it. Remove infected implants and all foreign material (inc cement)
Patient is usually left without a joint for 6 weeks with parenteral antibiotics for this time. Once the CRP has fallen and the wound has healed (infection under control) a revision joint replacement is performed.
Early local complications of joint replacement
Dislocation, infection, leg length discrepancy, nerve damage, ischaemia, bleeding, DVT.
Early general complications of joint replacement surgery
Hypovolaemia (due to blood loss) Shock Acute renal failure MI ARDS Urine/chest infection
Late local complications of joint replacement
Infection (from haematogenous spread), loosening, fracture, implant breakage, pseudotumour.
What is excision or resection arthroplasty?
Involves the removal of bone and cartilage on one or both sides of the joint. Good for smaller joints- quite disabling for larger joints.
What is arthrodesis?
Means surgical stiffening or fusion of a joint in a position of function. The remaining hyaline cartilage of the joint and subchondral bone is removed and the joint is stabilised resulting in bony union.
Pros and cons of arthrodesis
Pro- good for pain. Good for end stage disease.
Con- loss of function. May also increase pressure in surrounding areas leading to arthritic change.
What is osteotomy?
Surgical realignment of a bone which can be used for deformity correction or to redistribute load across an arthritic joint.
What is the aim of osteotomy in arthritis?
To shift the pressure from the diseased part of the joint onto the non-diseased part of the joint.
In which areas is injection into a tendon not advised?
Achilles tendon, extensor mechanism of the knee.
In which areas can injection of steroid help with inflammation?
Tennis elbow, adhesive capsulitis.
What is instability of a joint?
Abnormal motion of a joint resulting in subluxation or dislocation with pain and/or giving way.
What surgical strategies might you use for instability of a joint?
Ligament tightening/advancement
Ligament reconstruction using a tendon graft (e.g. ACL reconstruction).
In most cases, soft tissue procedures are highly unlikely to work and bony procedures are likely to be required (e.g. in patellofemoral instability-osteotomy).
What procedure would you use in carpal tunnel or cubital tunnel syndrome?
Nerve decompression.
What procedure would you use if the spinal nerve roots are being compressed by disc material or osteophytes?
Discectomy or spinal decompression.
What is osteomyelitis?
Infection of bone (includes spongy, marrow and compact bone)
What usually causes osteomyelitis?
Usually bacterial infection but can be fungal.
Describe the process of acquiring osteomyelitis
Once infected, enzymes from leucocytes cause local osteolysis (destruction of bone) and pus will form. This impairs the blood flow making the infection very difficult to eradicate. A dead fragment of bone called a sequestrum can break off and once this is present antibiotics alone will not cure the infection. New bone will form around the area of necrosis called an involucrum.
What can staph aureus infections do that others can’t?
It can infect osteocytes intracellularly making infection additionally difficult for the immune system to reach.
Who does acute osteomyelitis occur in?
Generally children (in the absence of a surgical cause) and immunocompromised adults.
What makes children so much more susceptible to bone infection than adults?
In children- the metaphysics of long bones contain torturous vessels with sluggish flow. This can allow bacteria to sit and accumulate.
Also in infants- the metaphases of bones are within the joint capsule and therefore they can get a co-existent septic arthritis.
Infants also have loosely applied periosteum so abscesses can spread.
What is Brodies abscess?
In children- a thin rim of sclerotic bone can grow to wall of an abscess.
It occurs in subacute osteomyelitis.
When would you get chronic osteomyelitis?
Untreated acute osteomyelitis
Where does chronic osteomyelitis tend to be?
In adults- tends to be in the axial skeleton with haematogenous spread from pulmonary or urine infections.
How can osteomyelitis be classified?
Superficial (affecting the outer surface of bone), medullary, localised (affecting the cortex and medullary bone) or diffuse (segment of bone is infected resulting in skeletal instability).
