Knee Ligament injury and rehab Flashcards
What does the MCL restrain
- 1ºrestrain: valgus
- 2ºrestrain: hyperextension and tibial rotation
- more slack in flexion and taut in extension
What does the LCL restrain
- primary restrain = varus
- secondary restraint = hyperextension and rotation
- slack on flexion and taut in extension
ACL attachments
- anterior intercondylar area of tibial plateau
- runs in a posterior lateral direction
- medial side of the lateral femoral condyle
What does the ACL limit
- anterior translation of the tibia on the femur (OC)
- posterior translation of the femur on the tibia
- secondary restrains varus and valgus forces as well as ER
How do the ACL fibers react during flexion and extension
- anterior medial fibers are taut in flexion
- posterior-lateral fibers taut in extension
- anterior shear/tension in open chain extension
PCL attachements
- posterior tibia plateau to the lateral side of the medial femoral condyle
What does the PCL limit
- limits posterior translation of the tibia on the femur
- anterior translation of the femur on the tibia
- secondary restrains = rotation, varus, and valgus
Joint capsule of the Tibiofemoral joint
- secondary restrain in all directions
- a completely torn ACL –> joint capsule will take up slack as well as MCL/LCL/PCL
- therefore do not want to do activities that will stretch
- intracapsular/extra synovial
Mechanism of injury common in the knee
- Valgus/ER/Flexion - Likely to injure MCL, ACL, Medial Meniscus (possibly lateral meniscus)
- Hyperextension: likely to injure the ACL in a non contact mechanism (common with female jumping athletes)
- Forced tibial ER: torn ACL
- Forced tibial IR: ACL wraps around PCL (can tear)
ACL tears common signs and symptoms
- Acute blow or twisting injury
- immediate effusion (bleeding into the joint)
- inability to continue to play
- 75% chance ACL injury diagnosis on history alone
Describe an torn ligament in relation to the stress strain curve
- stretch into plastic
- 4% strain = microtrauma
- 6-8% = 1º-2º strain
- > 8% = 3ºstrain/tear
How can you diagnosis grade of sprain with the amount of translation
- Grade 1 = 0-5 mm of translation with lachmans
- grade 2 = 5mm-1cm of translation
- grade 3 = >1cm
What is another way to diagnosis the sprain of an ACL
- end feel can be used
- normal abrupt/firm
- abnormal = soft as ACL is not stopping
Requirements for ligament healing
- torn ligament remain in proximity or within highly vascularized tissue
- Controlled motion stress stimulates and directs better healing
- protect against harmful stresses
How well do the MCL and ACL heal
- MCL any grade will heal as it is highly vascularized
- ACL grade 1&2 can scar and heal
- ACL grade 3 is not going to heal as it does not have enough blood flow
What forces to protect against
MCL/ACL
- MCL = valgus stress
- ACL = anterior translation (OC Anterior translation during extension)
Dynamic stablitiers for
1) ACL
2) PCL
3) MCL
4) LCL
1) ACL = hamstrings
2) PCL = quadriceps
3) MCL = pes anerinus muscle attachments
4) LCL = IT band/TL, glute max
Basic Principles for MCL non-op care
- promote early motion
- protect WB (hinge brace - control varus/valgus)
- get effusion under control
- retard muscle atrophy/active muscles
- enhance dynamic stability/proprioception and endurance
- limit stress on secondary support
ACL basic principles for ACL rehab
- promote early motion
- protect WB
- get effusion under control
- retard muscle atrophy/active muscles
- enhance dynamic stability/proprioception and endurance
- limit stress on secondary support
How to protectively WB - for ACL or non-op care
- avoid deep squat
- minimize anterior translation for last 45-0º (open chain extension)
- work on closed chain TKE to avoid anterior shear force
- strengthen 90-45º
ACL non-opconsiderations
- hamstring dominant
- important to continue jumping twisting with the brace
PCL rehab
- emphasis on quadriceps
- avoid OKC knee flexion (posterior translation of tibia on femur)
Women and ACL injuries
- disproportionate
- anatomical differences
- muscular and neuromuscular differences
- jump training: after puberty women land more quad dominant w/valgus collapse
- tell them to lean forward to engage the hamstrings
