Hip and Knee Disorders

Question 1

Risk factors for avascular necrosis?

Answer 1

Traumatic - femoral head/neck fracture and hip dislocation.

Non traumatic - alcohol abuse, corticosteroids, irradiation, haematological disease, dysbaric disorders, hypercoagulable states, connective tissue disorders, viral infections and idiopathic.

Question 2

Clinical features, investigations and management of AVN of the hip?

Answer 2

Insidious onset - buttock/going/thigh pain, sudden increase in pain may indicate femoral head collapse. Stiff hip on examination and patient may walk with a limp.

Investigations - plain radiograph will detect advanced disease but MRI is much better.

Management - Non-operative (symptom control), operative (core decompression, hip resurfacing or replacement).

Question 3

Features of Slipped Upper Femoral Epiphysis

Answer 3

It is fracture of the capital femoral physis causing the epiphysis to slip.
Common in adolescents during rapid growth or in obese children.

Presentation - Loss of internal rotation of the leg and hip/groin/medial thigh or knee pain.

Ix - AP and lateral (frog leg) views - steel sign and loss of shenton’s line.

Rx - Internal fixation.

Complications - osteoarthritis, AVN of femoral head, chondrolysis and leg length discrepancy.

Question 4

Features of quadriceps tendon rupture?

Answer 4

Occurs in elderly men with pre-exisiting tendonopathy.

Presentation - Pain, bruising and swelling, palpable defect, unable to extend knee against resistence.

Imaging - AP and lateral X-rays. Knee will show patella baja (low lying patella)

Management - Open repair followed by protection in cast or splint.

Question 5

Features of patella tendon rupture?

Answer 5

Commonly affects men aged 20-40.

Presentation: Pain, elevated patella with large haemarthrosis, unable to extend knee

Ix: AP and Lateral x-rays which show patella alta

Rx: Non operative = immobilisation in full extension. Operative = open repair of tendon.

Question 6

Risk factors for tendon rupture?

Answer 6

Previous tendon injury
Existing tendonopathy,
Previous corticosteroid injection,
Steroid use,
Co-morbidities (SLE, RA, CKD, diabetes),
Increasing age

Question 7

Presentation of meniscal tears?

Answer 7

Presentation - Pain worse on extension, knee may ‘give way’, knee locking, tenderness along joint line and positive thessaly’’s test

Examination findings: localised swelling and tenderness and reduced ROM

Possible tests: McMurray’s test and Apley grind test and Thessaly’s test

Question 8

Explain the Ottawa knee rules

Answer 8

Determines whether a patient required an X ray of knee. Patient required an x-ray if any of the following are present:
1. Age > 55 or above.
2. Patella tenderness.
3. Fibular head tenderness.
4. Cannot flex to 90 degrees.
5. Cannot weight bear (cannot take 4 steps)

Question 9

Investigations and management of meniscal tears?

Answer 9

Ix - MRI scan (first line), arthroscopy (gold standard).

Rx - Conservative management with RICE (rest, ice, compression and elevation). Physiotherapy can be used and then surgery may be required

Question 10

Explain features of an anterior cruciate ligament injury

Answer 10

Presentation - Sudden ‘popping’ sound, knee swelling (large haemarthrosis), instability, positive anterior drawer test and positive Lachman’s test (more reliable).
Usually occurs from forced flexion or hyperflexion of the knee.

Question 11

Explain the features of a posterior cruciate ligament tear

Answer 11

Less common than ACL. Usually occurs from hyperextension or forced displacement of upper tibia.

Presentation: Significant haemarthoris, posterior sag, generalised tenderness.

Question 12

Explain features of medical collateral ligament injury?

Answer 12

Often associated with injures to medial meniscus and ACL.
Presentation: bruising over medial aspect of knee + joint effusion. Tenderness. Laxity on MCL testing
Complications: Chronic valgus instability, MCL avlusion.

Question 13

Features of lateral collateral ligament injury?

Answer 13

Less common than MCL injuries.

Presentation: Bruising over lateral aspect of knee with swelling. Tenderness overlying ligament. Laxity on LCL.

Complications: Avulsion fracture at fibula head, damage to common peroneal nerve.

Question 14

Explain features of acetabular labral tear?

Answer 14

Presents with:
Hip/groin pain,
Snapping sensation around the hip,
Occasionally sensation of locking.

Question 15

Features of a Baker’s cyst?

Answer 15

Distention of gastrocnemius-semimembranous bursa. Either primary or secondary.

Presentation - swelling in popliteal fossa, if ruptures then it may produce symptoms similar to DVT (pain, redness and swelling). Foucher’s sign - Lump disappears or gets smaller when knee is flexed to 45 degrees.

First line Ix = Ultrasound

Question 16

Management of intracapsular hip fracture?

Answer 16

Undisplaced - Internal fixation or hemiarthroplasty if unfit.
Displaced - Arthroplasty: Total hip replacement is favored if able to walk independently without more than stick, not cognitively impaired and medically fit.

Question 17

Management of extracapsular hip fracture?

Answer 17

Stable intertrochanteric fracture - dynamic hip screw.

If reverse oblique, transverse or subtrochanteric fracture - intramedullary device.

Question 18

what is Meralgia paraesthesia?

Answer 18

Sensory symptoms of the outer thigh caused by compression of the lateral femora cutaneous nerve

Question 19

Presentation and management of meralgia paresthesia?

Answer 19

Burning, numbness, pins and needles or cold sensation over lateral aspect of leg. Worse with extension of the hip. May have hair loss over area.
Can do conservative management - rest, looser clothing, weight loss or phyiso.
Medical management - paracetamol, NSAIDs, neuropathic analgesia or injections (steroids/anaesthesia)
Surgical management - decompression, transection or resection of nerve.

Question 20

What is Osgood-Schlatter disease, the presentation and management?

Answer 20

Inflammation at the tibial tuberosity where the patella ligament inserts. Multiple small avulsion fractures occur causing growth

Presentation - Visible or palpable hard/tender lump at tibial tuberosity, pain in anterior aspect of knee, pain exacerbated by physical activity/kneeling/extension of knee.

Management - reduction in activity, ice and NSAIDs.

Question 21

What is Osteochondritis Dissecans?

Answer 21

Pathological process affecting subchondral bone.
Presents with:
Knee pain and swelling after exercise.
Knee catching, locking and/or giving way.
Feeling a painful ‘clunk’ when flexing or extending the knee.
Joint effusion, Tenderness on palpation of articular cartilage, Wilson’s sign.

Question 22

Investigations and management of Osteochondritis Dissecans?

Answer 22

Ix - X-ray (subchondral crescent sign or lose bodies), MRI (visualise lose bodies and assess stability of lesion).
Rx - ortho