Orthopaedics unit 1 joint conditions - deck 3

Question 1

How are the complications of arthroplasty categorised ?

Answer 1

They are divided into ones which are common to any surgery and specific complications to arthroplasty

Question 2

What are the main risks for anyone undergoing major surgery ?

Answer 2

1. DVT formation which can result in PE which can be fatal
2. Chest and urinary tract infections
3. Pressure sores

Question 3

Being old itself is unlikely to be a risk factor for complications developing during/after an operation - why do we say in general then that elderly people are at more risk ?

Answer 3

Because elderly people are more likely to have medical conditions predisposing them to complications

Question 4

What surgeries carry an especially high risk of DVT formation ?

Answer 4

• Hip and knee surgery
• Surgeries in general in and around the pelvis

Question 5

How can the specific complications to arthroplasty be further categorised ?

Answer 5

Into early (soon after op) and late complications (months - years afterwards)

Question 6

What are the 3 main specific early complications of arthoplasty that can arise ?

Answer 6

1. Dislocation
2. DVT ==> PE
3. Infection

Question 7

Why are joint prosthesis particuarly at risk of dislocation in the early stages following an arthroplasty?

Answer 7

The prosthesis will not be fully supported by the surrounding soft tissues. The muscles and their proprioceptors may be temporarily out of action, through surgical trauma and pain inhibition.

A capsule of scar tissue will not yet have formed around the prosthesis

Question 8

When is the hip prosthesis most at risk of dislocation ?

Answer 8

Before the effects of anaesthesia wears off

Question 9

The best agent for the prophylaxis of DVT formation is universally agreed - T or F?

Answer 9

False

Question 10

List the different methods which can be used as prophylaxis against DVT formation

Answer 10

1. Anti-coagulant drugs e.g. heparin
2. Compression/support stockings

Question 11

In general terms how do anti-coagulant drugs and compression stockings help prevent DVT & PE ?

Answer 11

1. Anti-coagulant drugs inhibit clotting
2. Compression stockings help blood flow by preventing blood pooling in the legs as this effect is known to increase clotting

Question 12

Give 2 examples of bacteria which can commonly cause infection of artificial joints

Answer 12

• Hospital bacteria such as staphylococcus aureus
• Human body (commensals), such as staphylococcus albus normally found on the skin

Question 13

What does the presence of foreign material e.g. an artificial joint do to the bodies ability to kill bacteria ?

Answer 13

It inhibits it - the reason why is unknown

Question 14

What measures are taken to help prevent infection in joint replacements?

Answer 14

Techniques include antibiotic prophylaxis and the provision of an ultra-clean air operating environment.

Question 15

If all the precautions and the ideal operating environment is available what should the rates of infections in joint replacements be ?

Answer 15

Immediate infections should be eliminated and long-term infections reduced to less than 0.1%

Question 16

Unfortunately in the United Kingdom NHS resources do not always provide the ideal operating environment - what is the more realistic infection rates for joint replacements in the UK ?

Answer 16

1-3% anything higher is unacceptable

Question 17

What are the 2 main specific late complications that can arise in joint replacements ?

Answer 17

1. Infection (so it can occur early or late)
2. Loosening and wear

Question 18

What are the 2 main possible reasons for late infection occurring in a joint replacement ?

Answer 18

• It is probable that most cases of infection are caused at the time of insertion of the prosthesis and it is unknown why some become apparent late on.
• Or infection may be froma blood borne source as a consequence of contaminations of the blood stream (bacteraemias)

e.g. tooth extractions cause significant bacteraemias and is a known cause of heart valve infections

Question 19

Can loosening and wear of an artificial joint be prevented ?

Answer 19

No it is to some degree probably inevitable

Question 20

Describe what rheumatoid arthritis is and how it arises

Answer 20

Rheumatoid arthritis is a chronic inflammatory disorder of many systems of the body, resulting in joint pain.

The exact cause of RA is unknown but it has some clear links with abnormalities of the immune system and there is growing evidence that there may be a genetic abnormality which causes an abnormal reaction to certain types of bacteria

Question 21

When does RA typically arise and is it more common in m or f ?

Answer 21

• It can occur at any age
• It is more common in females

Question 22

How is RA usually diagnosed ?

Answer 22

1. Diagnosis is based on clinical presentation
2. Laboratory tests and radiogrpahs can be used to aid diagnosis and prognosis

Question 23

What are the main presenting signs and symptoms of RA?

Answer 23

• Severe pain, swelling and deformity of the joints
• Morning stiffness which improves throughout the day
• The small joints of the hands and feet are most commonly affected - only in a minority are the larger joints affected
• It often affects joints bilaterally

Question 24

What is the main difference between the sitffness experienced by patients with OA and those with RA ?

Answer 24

• In RA they get morning stiffness which improves throughout the day
• In OA they can stiffness which is worse after physical activity

Question 25

Who is resonsible for prescribing the drugs to treat patients with RA?

Answer 25

A rheumatologist (a **clinician** who specialises in joint diseases)

Question 26

RA can result in soft tissue damage to the tendon sheaths and tendons themselves - what procedure can be done by an orthopaedic surgeon to limit the damage caused by the disease?

Answer 26

**A synovectomy can be done - this is a procedure which removes the synovium (synovial membrane)**

Question 27

Who is a synovectomy considered more for ?

Answer 27

The younger patient who retains movement, but who has pain, as it can reduce pain and stiffness Just like an osteotomy for OA

Question 28

In what joints can a synovectomy used to help treat RA often be useful, also what procedure may the synovectomy be combined with ?

Answer 28

The elbow and wrist, it may be combined with an excision arthroplasty. This combination can be useful in treating pain but can never allow full return of function due to the excision arthroplasty

Question 29

Describe what an excision arthroplasty is

Answer 29

This is a surgery that involves the removal of some component of the joint e.g. femoral head or patella

Question 30

What is the overall role of the surgeon in helping treat patients with RA?

Answer 30

The main goal is pain relief and return of function just as in OA

Question 31

Describe what avascular necrosis is (AVN)

Answer 31

1. AVN happens when the blood supply to the end of a bone is disrupted – either on a temporary or permanent basis. 2. Without a supply of blood, the affected bone and the tissue that surrounds it dies.

Question 32

What are the 2 main ways in which AVN can occur ?

Answer 32

1. **Due to trauma** occurring in an area where the blood supply is particularly vulnerable 2. Most commonly it occurs due to **no known reason**

Question 33

What are the 3 main areas at risk following trauma for developing AVN ?

Answer 33

1. The femoral head 2. The proximal part of the scaphoid in the wrist 3. The proximal part of the talus.

Question 34

What are the 2 main areas in which AVN occurs due to unknown circumstances ?

Answer 34

1. The lunate bone 2. The femoral head

Question 35

What are the 3 main groups of people that AVN occurs in, due to unknown circumstances ?

Answer 35

1. Chronic alcohol abuse 2. High dose steroid therapy 3. Deep sea divers (Caisson’s disease) - i.e. when deep sea divers develop decompression sickness

Question 36

What are the symptoms/presentation of AVN?

Answer 36

* The patient presents with **acute and often severe joint pain** (i.e. the joint pain comes on acutely) * Pain is **made worse by movement** * Pain to some degree relieved by rest. With the passage of time symptoms become indistinguishable from osteoarthritis and then it may be treated as such. Note the patient may be asymptomatic and the AVN is found incidentally on radiograph

Question 37

What is the unfortunate thing about AVN

Answer 37

Many patients are young, although still most common between 30-50

Question 38

How is AVN diagnosed ?

Answer 38

It is very difficult as there is no changes to be seen on X-ray initially early cases may only show changes on MRI As AVN progresses the bone appears dense on x-ray reflecting the absence of blood vessles

Question 39

What is the only way in which AVN can be reversed?

Answer 39

If a blood supply is reestablished to the bone naturally as surgical restoration of bone blood supply is not possible at the moment.

Question 40

If bone blood supply is re-established naturally in AVN what is the bone at risk off?

Answer 40

In the re-vascularising phase the bone is very soft and prone to distort, with secondary arthritic changes

Question 41

Describe the treatment of AVN

Answer 41

Treatment is non-specific. If possible the affected joint should be rested. Surgery is of no value in treating the underlying condition and often the surgeon is left to salvage the situation with a joint replacement. As such patients are often young (30-50) this is, as explained above in the management of OA, highly problematical (bring this up with prof abboud as this contradicts cortext which says - if the condition is detected early enough (pre‐collapse), drill holes can be made up the femoral neck and into the abnormal area in the head in an attempt to relieve pressure (decompression), promote healing and prevent collapse. Once collapse has occurred, the only surgical option is THR.)