Knee Elective

Question 1

Examples of elective knee

Answer 1

-OA
-Osteochondritis dissecans

Question 2

Risk factors for OA knee

Answer 2

-Age (>50)
-Obesity
-Family history
-Post # / septic arthritis / inflammatory arthritis

Most common site of OA, progressive loss of articular cartilage

Question 3

Presentation of OA knee

Answer 3

-Pain
-Swelling
-Stiffness (short duration)
-Late: Deformity, Laxity -> instability

-Swelling +/- deformity (intermittent)
-Feel: Crepitus
-Move: Reduced extension (fixed flexion deformity)
+/- Antalgic gait

Question 4

Investigations in OA knee

Answer 4

-X/Rs are weightbearing, and include:
=AP and Lateral
=‘Sunrise view’ for patellofemoral OA
=‘Rosenberg view’ (knee in 45° flexion) ->more sensitive way of assessing loss of joint space

Question 5

Management of OA knee

Answer 5

-Conservative
=Weight loss
=Exercise
=Physiotherapy
=Walking aids
-Medical
=NSAIDs
=Opioids
=Intra-articular steroids

-Surgical
= High tibial osteotomy (HTO) – young patient with medial OA (alter weight distribution)
=Unicompartmental knee arthroplasty (UKA) – unicompartmental disease
=Total knee arthroplasty (TKA)

Question 6

Describe osteochondritis Dissecans

Answer 6

-Separation of discrete area of subchondral bone +/- the overlying articular cartilage
-Idiopathic or traumatic (repetitive movements)
-Knees most common, followed by elbows
=Tends to affect the medial femoral condyle (MFC)
-Most prevalent during adolescence (10 – 20 y/o; 2 : 1 )♂ ♀
-This fragment may becoming a loose body within the joint

Question 7

Presentation of osteochondritis dissecans

Answer 7

-Pain, subacute after exercise
-Swelling/ oedema, free bodies
-Locking / clicking if the fragment is loose in the knee (more constant and severe symptoms are associated with presence of loose bodies)
-Feeling a painful ‘clunk’ when flexing or extending knee (involvement of lateral femoral condyle)

-Look: Effusion
-Feel: Tender over the medial femoral condyle when knee flexed
=Wilson’s sign for detecting medial condyle lesion - with the knee at 90° flexion and tibia internally rotated, the gradual extension of the joint leads to pain at about 30°, external rotation of the tibia at this point relieves the pain
-Move: potentially locked knee

Question 8

Investigation and management of osteochondritis dissecans

Answer 8

-X-ray (anteroposterior, lateral and tunnel views) - may show the subchondral crescent sign or loose bodies
-MRI - used to evaluate cartilage, visualise loose bodies, stage and assess the stability of the lesion (diagnostic)

-Rx – highly varied, but broadly:
=If not loose and child still growing –restricted weightbearing
=If not loose and growth complete –microfracture
=If unstable – internal fixation
=If elderly - TKA

Question 9

Types of bursitis

Answer 9

-Infrapatellar: kneeling
-Prepatellar: more upright kneeling