Knee Flashcards
When do you conservatively manage a meniscal injury?
- Able to weight bear
- Pain on McMurray’s only at full flexion (px + clunking later in range means it may be too far gone for conservative mgmt)
- Minimal injury/peripheral meniscal tear
What are the aims of conservative management?
- Increase ROM
- Address pain/swelling
- Strengthen (co-contraction between Q+H)
When’s it likely to refer to surgery for meniscal injury?
- Severe twisting injury
- Locking of joint
- Clunk+pain on McMurrays
- Not responding to 3 weeks of conservative management
Surgery = suturing, stitching, or cutting away torn part of meniscus
Describe the grades of ligament injury
Grade 1: pain, no swelling or laxity
Grade 2: pain, swelling+some laxity
Grade 3: +/- pain, swelling, gross laxity, sensation of instability
What is the ‘Unhappy Triad’?
ACL+MCL+meniscus
Valgus stress test sensitivity?
56-96% - so could be good to rule OUT a MCL problem
Management of collateral lig injuries?
Clinical healing occurs after several weeks, but microscopic remodeling can take 1+ years
Early mobilization very important!
- improves longitudinal alignment of collagen
- increases load bearing ability of the tissue
- increases concentration of collagen
- reduces laxity and increases tensile strength!
AIMS of conservative treatment:
- control swelling/pain
- provide control of movement (brace/tape)
- Restore ROM+strength
Based on grade of lig injury, how soon can someone expect to get back to sport?
Grade 1 - 2 weeks
Grade 2 - 4 weeks
Grade 3 - 6 weeks
What are risk factors for ACL injury?
- Fam hx
- Prev ACL injury
- Bony geometry? (ie. shallow intercondylar notch?)
- Poor neuromm motor patters
- Increase AP laxity
- Environmental factors (eg. cleats, synthetic floors)
There are different theories that describe the MOI for ACL injuries. Describe them: LIgament dominance theory Quads dominance theory Trunk dominance theory Leg dominance theory
Ligament dominance theory:
- injury d/t anything that strains lig past its ability to withstand; hip IR, knee valgus, hip add
Quads dominance theory:
- too much quad strength; in 20-30º of flexion if quads are too strong, turn on too early, or hams too late - hyperextension - ACL injury risk
Trunk dominance theory:
- an inability to control the trunk in 3D space; trunk motion and proprioception predicts risk of future knee lig injury
Leg dominance theory:
- side-side asymmetries in mm recruitment/strength/flexibility
What are acute symptoms of ACL injury?
Audible pop/snap
Effusion*
Pain
Instability
*with ACL injury - its highly vascularized - so immediate swelling - PERIARTICULAR; pt adopts 20-30º flexion to accomodate for swelling
Describe brush/swipe test
- brush UP on medial side; brush DOWN on lateral side
Anterior drawer + Lachmans’ general idea of sensitivity?
Anterior drawer - 22-95%
Lachmans* - 80-99%
*tested in 20-30º of flexion
How do you decide whether surgery is needed for ACL injury?
- Age
- Level of function needed
- Associated injury
- Degree of instability
Surgery should be delayed 3 weeks - if you operate too early when there’s still swelling/inflammation in the joint - then more likely to fibrose and lose ROM
What are teh different types of grafts for ACL?
Autograft - patella (mid 1/3), hamstring (semitendinosis/gracilis)
Synthetic - LARS (ligament augmentation+reconstruction system)
What is the difference in outcomes between conservative and surgical management of ACL injury?
- Forbell et al (2010) study
RCT in Sweden found:
- early or delayed surgery gives same outcomes
- in a post hoc analysis - rehab alone did better in the short term (3 months) compared to rehab+early surgery and rehab+delayed surgery; everyone had same level of outcomes at 2 year time point
- but this only measured FUNCTION
Whats the difference between patella vs hams autograft?
Autografts - in general no immune reaction
- patella can be good if subject needs hams (eg. sprinter)
- but patella graft can leave subject with knee pain
- hams graft better for knee pain but the donor site needs to be treated/rehabbed
What is LARS and what are its proposed benefits
LARS is an industrial strength polyester fibre - artificual ACL
Benefits:
- don’t have to deal with donor site problems
- (perceived) improvement in knee stability?
- early return to impact loading activities*
- minimal synovitis
- low current rupture rate
*pts 10x likely to rupture in 1st year and 3x more likely after that
Describe the conservative management for ACL injury
PREHAB:
- swelling+pain, ROM, strength
POST-OP REHAB:
- depending on where graft is from, address patella/hamstring
- day 1 - WBAT (crutches) - must keep knee extended to prevent fibrosis
- brace until quad control improves
- progression of strengthening
Describe the 4-phase rehab progression 0-12 months
Phase 1: 0-2 weeks
- swelling/ROM/strength
Phase 2 (2-12 weeks): - Full ROM/functional activities/balance
Phase 3 (3-6 months) - jogging+sport specific drills
Phase 4 (6mons-12mons) - RTS
How can the diagnosis of PCL injury be made?
MOI (hyperflexion or direct blow - dashboard injury) Area of pain (post/posterolateral knee) Instability Swelling/bruising in the calf Clinical tests + (post sag/post drawer) MRI/Arthoscopy
Patellofemoral dislocation risk factors (name 5)
- Femoral anteversion
- Genu valgum
- Subtalar pronation
- Increased Q angle
- Shallow femoral groove
- Patella alta
- Lateral tightness + medial weakness
- Lig laxity
- Prev dislocation
Patellar dislocation physical exam
Obs - swelling/gross deformity
Tests - patellar apprehension test
Patellar dislocation management
Conservative:
- immobilze in cast/brace/splint (3-7 weeks)
- address contributing factors
- strengthening (VMO)/coordination
