Knee OA - # clinic

Question 1

RF knee OA

Answer 1

• Genetic
• Increasing age
• Female
• Obesity
• Low bone density
• Previous joint injury
• Occupational or recreational stresses on joint
• Reduced surrounding muscle strength
• Any joint laxity/misalignment

Question 2

Pain in knee OA

Answer 2

• Felt around knee
• Can radiate to thigh and hip
• Exacerbated by exercise, relieved by rest

Question 3

Exam for OA

Answer 3

• Bilateral often
• Reduced function and ROM
• Crepitus
• Fixed flexion deformity
• Joint line tenderness/bony swelling (osteophytes)
• Quadriceps muscle wasting due to loss of use
• Varus deformity

Question 4

Views for x-ray knee

Answer 4

• AP and lateral
• Can have skyline view of patella to see involvement

LOSS

Question 5

Classifiying severity of knee OA

Answer 5

Kellgren and Lawrence system

Question 6

Kellgren and Lawrence system

Answer 6

• 0 - no radiographic features of OA present
• 1 - unclear joint space narrowing and possible osteophytic lipping
• 2 - definite osteophytes, possible joint space narrowing on AP weight bearing views
• 3 - multiple osteophytes, definite joint space narrowing, evidence of sclerosis, possible bony deformity
• 4 - large osteophytes, marked joint space narrowing, severe sclerosis, bony deformity

Question 7

Management OA knee - initial

Answer 7

• Lifestyle - weight loss, exercise, smoking cessation
• Analgesia to ensure mobility using WHO ladder
• Physio - slow disease progression

If not work, surgical

Question 8

Surgical management knee OA

Answer 8

• Total knee replacement - most pts
• Partial (unicondylar) knee replacement - 10%
• Osteotomy - considered in younger patients, realigns joint and redistributes mechanical force

Question 9

Total knee replacement

Answer 9

• Advanced OA
• Plastic and metal inserts replace bone and cartilage in all sections of knee
• Function for at least 10yrs

Question 10

Partial knee replacement

Answer 10

• Disease localised to medial or lateral compartment
• More conservative = faster recovery time
• May need conversion to total knee replacement at later date

Question 11

Where does patella rest?

Answer 11

In trochlear groove on femur

Question 12

Patellofemoral OA

Answer 12

• OA affecting articular cartilage along trochlear groove and on underside of patella

Question 13

RF for patellofemoral OA

Answer 13

• Patella dysplasia - patella not fitting properly into trochlear groove
• Previous patella #

Question 14

Presentation of patellofemoral OA

Answer 14

• Anterior knee pain
• Worse with activities that put pressure on patella eg climbing flight of stairs
• Use skyline x-ray view to see

Question 15

Management patellofemoral OA

Answer 15

• Conservative - same as knee OA
• If unsuccessful - patellofemoral replacement
• BUT this cannot be carried out if there is OA affecting other parts of knee - would need total knee replacement if this was the case

Question 16

Diagnosing knee OA

Answer 16

Can diagnose without investigations if:
* patient is > 45 years
* has exercise related pain
* no morning stiffness or morning stiffness lasting > 30 minutes

Question 17

Analgesia OA

Answer 17

• Topical NSAIDs first line
• Oral NSAIDs if these do not cover pain - consider PPI
• Paracetamol not recommended in current NICE guidelines

Question 18

Injections for knee OA

Answer 18

• Intraarticular corticosteroid - limit to 3-4 injections per year to minimise cartilage damage - SHORT TERM PAIN RELIEF
• Intraarticular hyaluronic acid - evidence mixed, may help some

Question 19

Sequence to view joint x-rays

Answer 19

ABCS
* Alignment
* Bone texture
* Cortices
* Soft tissue

Question 20

OA vs RA x-rays

Answer 20

OA:
LOSS
Loss of joint space = assymetrical
DIPJs and 1st CMJ

RA:
LESS
Loss of joint space = symmetrical
MCPJs and PIPJs

Question 21

Knee replacement success rate`

Answer 21

80-85% of people are happy
This means 15-20% are not

Question 22

Complications from joint replacement surgery to discuss

Answer 22

• DVT/PE
• Bleeding
• Pain
• Prosthesis loosening
• Stiffness
• Altered leg length
• Urinary retention
• Post op delirium
• Infection
• Keloid scarring
• Tendon/bone/nerve/BV damage
• Amputation
• Death

Question 23

Procedure of knee replacement

Answer 23

• Less than 1hr actual op - bit longer with anaesthetic to do etc
• Tourniquet around leg - limit bleeding
• Incision in middle of front of knee
• Open capsule
• Cut distal femur and proximal tibia
• New proesthetic joint in

Question 24

Recovery from knee replacement

Answer 24

• In hopsital for 1-2 nights
• Daily exercises needed for weeks
• First 2-4 weeks are hard
• 10 weeks off work average
• Drive within 4-6 weeks
• Takes 3-9 months to fully settle

Question 25

Permanent things from knee replacement

Answer 25

• Numbness from scar laterally on knee - severe infrapatellar branch of saphenous nerve
• Uncomfy to kneel on knee forever - although can

Question 26

How long does knee replacement usually last?

Answer 26

10yrs at least

Question 27

Pre-theatre investigations

Answer 27

• All baseline things - check status for surgery eg FBC, U&E, LFT, CRP
• Group and save (+crossmatch if expect blood loss)
• Height, weight
• Basic obs inc BP
• ECG and echo
• MRSA screening
• Spirometry if known chronic lung disease
• Urine dip - UTI?

Question 28

Chemo Thromboprophylaxis for knee surgery

Answer 28

• Aspirin for 14 days OR
• LMWH for 14 days + antiembolic stockings until discharge
• Have LMWH 6-12hrs after surgery

Question 29

Antibiotic prophylaxis for elective joint replacements with prosthesis

Answer 29

• Check local guidelines
• Kettering is Cefuroxime as long as no previous history of C.diff
• Have at induction then 8hrs after, then 16hrs after
• Need to have antibiotic that has longer half life than operation usually otherwise need rpt doses