Knee OA - # clinic Flashcards
RF knee OA
- 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
Pain in knee OA
- Felt around knee
- Can radiate to thigh and hip
- Exacerbated by exercise, relieved by rest
Exam for OA
- 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
Views for x-ray knee
- AP and lateral
- Can have skyline view of patella to see involvement
LOSS
Classifiying severity of knee OA
Kellgren and Lawrence system
Kellgren and Lawrence system
- 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
Management OA knee - initial
- Lifestyle - weight loss, exercise, smoking cessation
- Analgesia to ensure mobility using WHO ladder
- Physio - slow disease progression
If not work, surgical
Surgical management knee OA
- Total knee replacement - most pts
- Partial (unicondylar) knee replacement - 10%
- Osteotomy - considered in younger patients, realigns joint and redistributes mechanical force
Total knee replacement
- Advanced OA
- Plastic and metal inserts replace bone and cartilage in all sections of knee
- Function for at least 10yrs
Partial knee replacement
- Disease localised to medial or lateral compartment
- More conservative = faster recovery time
- May need conversion to total knee replacement at later date
Where does patella rest?
In trochlear groove on femur
Patellofemoral OA
- OA affecting articular cartilage along trochlear groove and on underside of patella
RF for patellofemoral OA
- Patella dysplasia - patella not fitting properly into trochlear groove
- Previous patella #
Presentation of patellofemoral OA
- Anterior knee pain
- Worse with activities that put pressure on patella eg climbing flight of stairs
- Use skyline x-ray view to see
Management patellofemoral OA
- 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
Diagnosing knee OA
Can diagnose without investigations if:
* patient is > 45 years
* has exercise related pain
* no morning stiffness or morning stiffness lasting > 30 minutes
Analgesia OA
- Topical NSAIDs first line
- Oral NSAIDs if these do not cover pain - consider PPI
- Paracetamol not recommended in current NICE guidelines
Injections for knee OA
- 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
Sequence to view joint x-rays
ABCS
* Alignment
* Bone texture
* Cortices
* Soft tissue
OA vs RA x-rays
OA:
LOSS
Loss of joint space = assymetrical
DIPJs and 1st CMJ
RA:
LESS
Loss of joint space = symmetrical
MCPJs and PIPJs
Knee replacement success rate`
80-85% of people are happy
This means 15-20% are not
Complications from joint replacement surgery to discuss
- 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
Procedure of knee replacement
- 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
Recovery from knee replacement
- 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
Permanent things from knee replacement
- Numbness from scar laterally on knee - severe infrapatellar branch of saphenous nerve
- Uncomfy to kneel on knee forever - although can
How long does knee replacement usually last?
10yrs at least
Pre-theatre investigations
- 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?
Chemo Thromboprophylaxis for knee surgery
- Aspirin for 14 days OR
- LMWH for 14 days + antiembolic stockings until discharge
- Have LMWH 6-12hrs after surgery
Antibiotic prophylaxis for elective joint replacements with prosthesis
- 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
