Bursitis; Compartment syndrome; Baker's cysts

Question 1

Define bursitis [1]
Define olecranon bursitis [1]

Answer 1

Bursitis is acute or chronic inflammation of a bursa.
A bursa is a jelly-like sac that usually contains a small amount of synovial fluid. A bursa lies between a tendon and either bone or skin to act as a friction buffer and facilitate movement of adjacent structures.

Oleceranon bursitis:
- Olecranon bursitis describes inflammation of the olecranon bursa, the fluid-filled sac overlying the olecranon process at the proximal end of the ulna. This bursa exists to reduce friction between the posterior aspect of the elbow joint and the overlying soft tissues. I

Question 2

Describe some causes of olecanon bursitis [5]

Answer 2

• Repetitive trauma (29%) - writers and students leaning on elbows, plumbers, miners
• Direct trauma (17%)
• Infection (33%) - 50% of cases occur in immunosuppressed patients (alcohol abuse, diabetes, taking steroids, renal failure, malignancy). 90% of cases due to Staphylococcus aureus.
• Gout (7%)
• Rheumatoid arthritis (5%)
• Idiopathic (5%)

Question 3

Describe the clinical features of olecranon bursitis

Answer 3

non-septic olecranon bursitis:
- swelling over the olecranon process; tenderness and erytheme also common

Septic bursitis:
- tenderness over the bursa (92-100%)
-fever (40%)

TOMTIP: Movement at the elbow joint should be painless until the swollen bursa is compressed in full flexion.

Question 4

Investigations for bursitis? [2]

Answer 4

Not always needed if a clinical diagnosis can be made and there is no concern about septic arthritis, e.g. a well patient without pain, fever or erythema of the bursa.

Aspiration of bursal fluid for microscopy (Gram stain and crystals) and culture is essential if septic bursitis is considered. Purulent fluid suggests infection whereas straw-coloured bursal fluid favours a non-infective cause.

Question 5

Management for olecranon bursitis? [3]

Answer 5

RICE & NSAIDs

Local cortiocosteroids can be considered if chronic

Septic bursitis - give abx

Question 6

Describe where trochanteric bursitis occurs [1]

Answer 6

Trochanteric bursitis refers to inflammation of a bursa over the greater trochanter on the outer hip.

Question 7

What causes trochanteric bursitis? [4]

Answer 7

Friction from repetitive movements
Trauma
Inflammatory conditions (e.g., rheumatoid arthritis)
Infection – referred to as septic bursitis

Placement:
- Weak glute muscles causes increased pressure on bursa causing inflammation

Question 8

Describe the presentation of trochanteric bursitis [3]

Answer 8

Lateral (outer hip) thigh pain that may radiate down outer thigh

Aching or burning pain - worse with activity, standing after sitting or sitting crossed legged

Tenderness over greater trochanter but NO swelling

Often painful when sleeping on them

Question 9

How do you test for trochanteric bursitis?

Answer 9

Trendelenburg test
- Ask to stand on affected side
- Otherside drops down = positive

Resisted abduction, internal and external rotation of hip

Question 10

Mx of trochanteric bursitis? [4]

Answer 10

Rest
Ice
Analgesia (e.g., ibuprofen or naproxen)
Physiotherapy
Steroid injections

Question 11

State the causes of acute compartment syndrome [4]

Answer 11

Trauma
- Long bone fracture
- Crush injuries
- Burns

Vascular injury

Over tight casting / bandaging

Intravenous drug injection:
- Substances injected intravenously may cause inflammation or damage to tissues and vessels, resulting in increased compartment pressures.

Question 12

State the causes of chronic compartment syndrome [3]

Answer 12

Vigorous exercise:
- Regular, intense exercise can increase muscle mass and volume, leading to raised intracompartmental pressures during activity.

Anatomical abnormalities:
- Abnormalities such as malalignment syndromes may predispose individuals to CECS.

Biomaterials use:
- Use of certain biomaterials for soft tissue augmentation has been linked with CECS due their potential for causing an inflammatory response.

Question 13

Describe the pathophysiology of compartment syndrome

Answer 13

Pressure within a fascial compartment is abnormally elevated, cutting off the blood flow to the contents of that compartment.

This impedes venous outflow leading to venous congestion and oedema formation

Resultant oedema further escalates the intracompartmental pressure

This cycle continues until the intracompartmental pressure approaches or exceeds systemic arterial pressure. When this occurs, it hampers arterial inflow into the compartment.

This causes ischaemia and can lead to necrosis

Question 14

5Ps of CS? [5]

Answer 14

P – Pain “disproportionate” to the underlying injury, worsened by passive stretching of the muscles
P – Paresthesia
**P **– Pale
P – Pressure (high)
P – Paralysis (a late and worrying feature)

TOM TIP: Disproportionate pain is a key characteristic of compartment syndrome. The pain is so severe that pain medications are not effective.

NB Note that pulseless is not a feature, differentiating it from acute limb ischaemia. The pulses may remain intact depending on which compartment is affected.

Question 15

How do you investigate for CS?

Answer 15

Clinical findings

ICP measurement
- is performed using a specialised device that measures the pressure within the muscle compartment.
- The normal resting pressure in a relaxed muscle compartment should be less than 10 mmHg.
- A differential diagnosis can be made if ICP is >30 mmHg or if there is a delta pressure (diastolic blood pressure - ICP) of < 20-30 mmHg.

Creatine kinase - elevated (but not specific)

Urinalysis: Myoglobinuria

Question 16

How do you differentiate CS to peripheral vascular disease? [2]

Answer 16

PVD typically presents with intermittent claudication (pain that occurs during physical activity and alleviates with rest)

Ankle-brachial index (ABI) measurement and angiography are useful diagnostic tools in PVD but would not provide relevant information in a case of suspected compartment syndrome.

Question 17

Describe what is meant by Volkmann’s contracture [1]

Answer 17

A permanent flexion contracture of the hand at the wrist, resulting in a claw-like deformity of the hand and fingers.

The persistent ischaemia leads to necrosis of muscle tissue resulting in shortening and fibrosis, hence causing a claw-like deformity.

Question 18

How do you manage comparment syndrome? [1]

Answer 18

Emergency fasciotomy is the definitive management. Ideally, this should be as soon as possible after injury (e.g., within 6 hours).

The incision should be long enough to adequately decompress all involved compartments.

Patients require repeated trips to theatre (every few days) to explore the compartment for necrotic tissue, which needs to be debrided

A skin graft may be required if the wound cannot be closed around the compartment.

Question 19

Why do CS patients require aggressive IV fluids? [1]

Answer 19

Myoglobinuria may occur following fasciotomy and result in renal failure and for this reason these patients require aggressive IV fluids

Question 20

Why might compartment syndrome lead to a patient having low Na? [1]

Answer 20

Syndrome of inappropriate antidiuretic hormone secretion (SIADH):
- Although rare, SIADH has been reported in patients with severe compartment syndrome.
- It results from an abnormal response to stress causing excessive release of antidiuretic hormone leading to hyponatraemia.

Question 21

The popliteal fossa is the diamond-shaped hollow area formed by the [4]

Answer 21

Semimembranosus and semitendinosus tendons (superior and medial)
Biceps femoris tendon (superior and lateral)
Medial head of the gastrocnemius (inferior and medial)
Lateral head of the gastrocnemius (inferior and lateral)

Question 22

Define what is meant by a Baker’s cyst [1]

Answer 22

A Baker’s cyst is an extension of the knee synovium that develops between the medial head of gastrocnemius and the semi-membranosus muscle

Question 23

What is the underlying pathophysiology of Baker’s cysts? [4]

Answer 23

In adults, Baker’s cysts are usually secondary to degenerative changes in the knee joint. They can be associated with:
* Meniscal tears (an important underlying cause)
* Osteoarthritis
* Knee injuries
* Inflammatory arthritis (e.g., rheumatoid arthritis)

Synovial fluid is squeezed out of the knee joint into the popliteal fossa

Question 24

Describe what is meant by Foucher’s sign [1]

Answer 24

When knee fully extended (standing) - the fossa pops out

When flexed to 45degrees - the cyst dissapears

Question 25

A ruptured Baker’s cyst can rarely cause []

Answer 25

A ruptured Baker’s cyst can rarely cause compartment syndrome.

Question 26

First line investigation of a baker’s cyst is? [1]

Answer 26

US - can rule out DVT at the same time

Question 27

Management of baker’s cyst? [1]

Answer 27

Asymptomatic:
- Nothing

Symptomatic:
- Modify activity
- Analgesia
- Physio
- US guided aspiration
- Steroid injections
- Arthroscopic procedures to treat underling degenerative disorders and meniscal tears