Knee Flashcards
What radiographic changes are seen with osteoarthritis?
Loss of joint space
Osteophytes
Subchondral sclerosis
Subchondral cysts
Where is knee OA most commonly seen?
Posterior patella
Medial compartment ➔ varus deformity
List the signs of osteoarthritis of the knee
Joint swelling Wasting of quadriceps and/or calfs Deformity: most commonly varus deformity Fixed flexion of knee: posterior patellar involvement Joint line tenderness
Name 3 causes of secondary osteoarthritis
Post-traumatic: fracture, meniscus tear, ligament tear Post-operative Malposition Mechanical instability Osteochondritis dissecans
Name 5 predisposing factors for osteoarthritis
Increased BMI Genetics Increasing age Occupation Trauma Inflammatory arthritis Hyperparathyroidism Haemochromatosis Wilson's disease Acromegaly
Outline the management options for knee osteoarthritis
Lifestyle: weight loss, knee support
Physiotherapy
NSAIDs
Steroid injection
Arthroscopy
Osteotomy
Knee replacement: total or unicondylar
-plus 6-8 weeks post-op rehab
What clinical features support surgical intervention for osteoarthritis?
Night pain
Increasing impact on QoL
Increasing deformity
What is the benefit of knee replacement?
Improves knee pain*
Returns some function: usually limited to 90 degrees of flexion
What is the average lifespan of a total knee replacement?
10-15 years
Younger patients tend to wear it out faster ➔ recommended for unicondylar replacement if only one compartment affected
Describe the Outerbridge classification of cartilage damage
- normal cartilage
I. soft cartilage with swelling
II. partial-thickness defect with fissures that do not reach subchondral bone
III. fissuring to level of subchondral bone
IV. exposed subchondral bone
Name 3 causes of anterior knee pain +/- swelling
Patellofemoral pain syndrome Recurrent patella subluxation Patella tendinopathy Iliotibial tract syndrome Medial shelf syndrome Hoffa's fat pad syndrome Osgood-Schlatter disease
Define patellofemoral pain syndrome
Pain and crepitus around the patella. Often aggravated by climbing stairs and running.
How is patellofemoral pain syndrome treated?
NSAIDs and paracetamol
Physiotherapy: quadriceps strengthening*
-80% success rate
Injection, PFJ replacement or TFR
How should an acute traumatic knee be managed?
History
X-ray to rule out fracture/dislocation
Splint and repeat exam at 3 weeks
MRI
Physiotherapy
Knee arthroscopy/reconstruction
What are the symptoms of bone bruise?
Pain or tenderness Swelling Change in skin colour Joint inflammation Joint stiffness
Describe the types of bone bruise
Subperiosteal: after traumatic injury
Interosseous: repeated pressure
Subchondral: compression or rotation
Name 2 risk factors for bone bruising
High-impact sport
Physically demanding job
Not wearing protective equipment during sport/job
Osteoarthritis
What is the prognosis of bone bruising?
Tends to self-resolve within months, unlikely to progress
Name 3 complications of total knee replacement
Infection
Bleeding
Pain/tenderness around scar
DVT/PE
List the signs seen with injury to a collateral ligament
Effusion +/- tenderness over affected ligaments
Associated common perineal nerve injury
Describe the management of injury to a collateral ligament
Rest + firm support
Surgery
-rarely needed for isolated MCL
-required for LCL if joint instability present
What is the typically cause of an ACL tear?
Twisting injury to the knee with foot planted on ground
Describe the clinical features of an ACL tear
Sudden onset of swelling: haemarthrosis
Unable to continue at time of tear
Knee giving way, instability esp when twisting
Swelling or popping suggests 70% likelihood of ACL tear
Name 3 tests used to assess an ACL tear
Lachman test*: flexion at 30 degrees
Anterior draw test: flexion at 90 degrees
Pivot shift test: done under anaesthetic
What treatment options exist for ACL tear?
3 weeks rest
Physiotherapy
ACL reconstruction: young or knee instability
How are ACL injuries classified?
Grade I: fibres stretched, but no tear. Little tenderness and swelling. Joint does not feel unstable or give out.
Grade II: fibres partially torn. Little tenderness and moderate swelling. Joint may feel unstable or give out.
Grade III: ACL ruptured. Tenderness. Ligament cannot control knee movements.
What is the commonest cause of meniscal tears?
Medial: Twisting or hyperflexion injury
Lateral: Adduction + internal rotation
Describe the clinical features of meniscal tears
Knee locking: fragments lodge between femur and tibia
Tender joint line
Unable to continue
Delayed swelling of knee
What investigation is ideal for meniscal tears?
MRI: tear location, morphology, length, depth, stability
What management options are available for meniscal tears?
Conservative
Arthroscopic repair/excision: locked knee, cysts, or persistent symptoms
Name 3 types of bursitis affecting the knee
Pre-patellar bursitis: housemaid’s knee
Infra-patellar bursitis: clergyman’s knee
Semi-membraneous bursitis: popliteal cyst
Define osteochondritis dissecans of the knee
Defect in subchondral region with partial or complete separation of the bone fragment.
Caused by repetitive overloading.
Describe the clinical features of osteochondritis dissecans
Poorly localised pain, exacerbated by exercise Intermittent effusion Occasional locking Crepitation Tender affected femoral condyle
What is the treatment of osteochondritis dissecans?
Conservative if stable lesion
Arthroscopic stabilisation excision
Which patient group is most commonly affected by osteochondritis dissecans?
Males (2:1) aged 13-21
Define Osgood-Schlatter disease
A common self-limiting cause of pain below the knee in adolescents. Caused by inflammation where the patellar tendon inserts into the tibia.
Pain on active extension of the knee against resistance.
Describe one congenital knee problem
Discoid lateral meniscus (incomplete or complete).
Excess covering of tibia leads to the knee being more prone to mechanical symptoms (locking, catching, giving way) and tears.
Treatment: knee arthroscopy
