Sports Med Exam 3
Knee Joints
Tibiofemoral: where the tibia fits into the femur
Patellofemoral: Back of the patella and the femur
Proximal Tibial Fibular: Where the fibula fits into the tibia
The kinetic chain: an engineering concept used to describe human movement
Rigid, overlapping segments are connected via joints creating a system whereby movement at one join produced or affected movement at another joint in the kinetic link
All synovial joints have: Joint Capsule, Joint Space, Hyaline Cartilage, Synovial membrane, Synovial Fluid
Static Restraints?
MCL: three layers. Deep layer is attached to the medial meniscus. It can tear the meniscus is pulled
LCL: extracapsular
Tear the MCL: intracapsular swelling
Tear the LCL: extracapsular swelling
Dynamic Structures: all the muscles and tendons that cross the joint
Provides stability to the joint
Anterior: Quads, Vasti Group, IT Band, Pes Anserine group
Posterior: Popliteus, Hamstrings, Gastroc
Hamstrings stabilize the ACL
Quadriceps stabilize the PCL
ACL stops forward movement of the tibia on the femur
PCL stops posterior movement of the tibia on the femur
Benefit of same day initial evaluation?
Pay attention to swelling and pain
History for Knee Injury
Pop/Snap: ligament or meniscus
Feels like knee is giving out: osteochondral, ACL, meniscus tears
Where is the pain? Things that are too deep
Positives to doing Closed Chain Activity?
Improves stability
Multiple joints working
Better proprioceptive input
Positives to doing Open Kinetic Chain?
Helpful for isolation
Lacrosse, Basketball, Soccer have higher incidences of tearing an ACL
Whereas Field Hockey is played closer to the ground in a loaded position
Common Mechanisms:
Acute: direct blow, cutting with foot planted, twisting w knee flexed, hyperextension, hyperflexion
Chronic: predisposing factors, repetitive stress, overuse
Observation
Initially may have no effusion but effusion develops within onset to 12 hours
Effusion: an abnormal collection of fluid inside of a hollow space between tissue
Knee Swelling
However all knee swelling is not the same
If it happens within 12-24 hours, then it is a bleeding knee joint capsule
Hemarthrosis: blood inside the joint
If it is a delayed capsular effusion it is synovial
Palpations for the knee should be done with the knee bent
Special Tests
Lachmann test for ACL tear
Sensitivity: the ability of a test to correctly identify those with a disease
Specificity: is the ability of the test to correctly identify those without the disease
Test specificity: the ability to rule out the tissue that is being tested
Stress Test: stressing a joint to determine if a ligament is intact or not and how damaged it is
Stresses to the knee
Valgus stress: some kind of force pushing the leg in medially
Varus stress: some kind of force pushing the leg out laterally
Patellar Anomalies
Patella baja: lower patella
Patella alta: higher patella
Shape of patella
Type 1: Normal
2-4: might be flat on the bottom or elongated
Degree of instability: 1, 2, 3, the reason we find this is through stress tests
MCL stops valgus force
LCL stops varus force
Medial Instability: direct blow from the lateral side towards the medial. MCL damaged
Swelling along the medial side of the knee. Pain and joint laxity with a valgus test
Positive stress test when the knee is straight it is a worse injury
Bent knee and get a little bit of pain and movement it would be MCL
Lateral Instability: varus force often when the tibia is internally rotated. LCL damaged. Not common
Swelling along lateral side of knee Pain and joint laxity with a Varus test
Management of MCL or LCL
Modalities, Rehab
ACL and PCL Lecture
ACL stops anterior movement on the tibia on the fixed femur, stops posterior movement on the femur on a fixed tibia
PCL stops posterior movement on the tibia on the fixed femur, stops anterior movement on the femur on a fixed tibia
Two bundles of the ACL: Anteromedial, Posterolateral: A/P
Two bundles of the PCL: Posteromedial, Anterolateral: P/A
Anterior Portions of ACL and PCL are tight in knee flexion
Posterior Portions of ACL and PCL are tight in knee extension
ACL (Anterior Instability)
- Most common ligament injured in the knee
- Contact or Non Contact
- ACL can tear along with MCL
ACL becomes tight when there is Internal rotation of the femur on a fixed tibia as the knee extends
Hemarthrosis happens within minutes to hours
Lachman should be done ASAP
Females have a higher incidence rate of ACL tears compared to Males
ACL is one of the only types of injuries that the NIH funds studies with ACL tears
Risk factors for gender disparity in ACL injury
Bony anatomy: Larger Q angle and more Knee Valgus
Limb alignment: wider pelvis, femurs rotated inwards, genu valgum
Intercondylar notch: smaller/narrower notch
Ligament size and mechanical properties: smaller and weaker ligaments
Females tend to rely more on their quads than hamstrings
Quad dominant
ACL Injuries:
Use Lachman to test for ACL injury
Autograft: tissue from your own body
Allograft: tissue from a cadaver
Benefits of patellar tendon: piece of bone on each end and good healing ability. BPTB
Quad Tendon: Quad tendon and piece of bone on one end
Downside to patellar tendon: taking out the middle third of the person’s patella tendon. Predisposed to patellar tendon tear
Negatives: people are worried about disease transmission. There are truly no negatives to it
In the end they are all really similar though. No gold standard way to reconstruct an ACL
Posterior Instability (PCL)
Anterior force just below the knee
Falling onto the tibial tuberosity
Most PCL injuries will not be operated on
Usually can heal on their own because the quads are always stronger
Rotational Instabilities of the Knee Lecture
Anterior Movement of the tibia: PCL
Posterior Movement of the tibia: ACL
Valgus Movement of the tibia: MCL
Varus Movement of the tibia: LCL
Anteromedial: Medial portion of the tibia goes forward
Anterolateral: Lateral portion of the tibia goes forward
Posteromedial: Medial portion of the tibia goes backward
Posterolateral: Lateral portion of the tibia goes backward
Anteromedial is the most common because it is the most common MOI: Planting and cutting mechanism
However, posterolateral: if you do major damage to the posterior lateral section, Common Peroneal nerve and major arteries can also be damaged. A tibiofemoral dislocation
If tibia goes forward: ACL torn
If tibia goes back: PCL torn
It is common to have an isolated ACL and can probably function fairly well
If there is a rotational mechanism then you are most likely to have multiple structures injured
If a primary and secondary stabilizer are torn it is rotational
If a primary is torn and not a secondary it is a single plane
Medial Portion of the knee: MCL, Anteromedial capsule, Posteromedial capsule, Pes tendons, medial hams
Lateral portion: Anterolateral capsule, Posterolateral capsule, IT Band, LCL, Popliteus, Biceps femoris, common peroneal nerve, posterior tibial arteries
Static Stabilizers
Medial (MCL, Medial Capsule)
Lateral (LCL, Lateral Capsule)
Anterior (ACL, Ant Med and Ant Lateral Capsule areas)
Posterior (PCL, Post Med and Post Lateral Capsule areas)
Anteromedial Injury is the most common multi-ligament knee injury
Unhappy Triad: MCL, ACL, Medial Meniscus
Posteromedial Injury
PCL, MCL, Post med and Lateral capsule
Anterolateral Injury
Often non-contact
ACL and ITB
Posterolateral Injury
Contact/collision
Knee goes into excessive hyperextension
Injured: PCL, ACL (extreme), LCL, Arcuate
Posterolateral Corner Injury
Often contact, can be non-contact
Can be catastrophic
Meniscal and Patellofemoral Injuries
Some meniscus injuries can be played on and some cannot. Why?
It has a lot to do with where is the tear and how big/shape.
Medial meniscus is larger and c shaped
Lateral meniscus is smaller and o or oval shaped
Peripheral is the outside: which are attached to the tibia
Free edge portion: (inside) not attached to the tibia
Medial Meniscus is attached to the capsule and the deep portion of the MCL
Meniscus spread out the weight bearing load from the femur and tibia
Functions of the Meniscus
Meniscus protect the condyle
Meniscus dissipate forces
Provide stability
Help make sure tibiofemoral motion is normal
Meniscal Blood Supply:
Red-Red zone: has a lot of blood supply
Red-White zone: has decent blood supply
White-White zone: no blood supply
In regard to whether or not the meniscus is fixable…
The blood supply to the meniscus
Some meniscal tears are fixable, and some are not ever fixable.
It depends on whether or not they are going to heal
It takes 6 weeks for fibrocartilage to heal so if you get stitches you cannot do anything for these weeks
History of meniscus tears
Acute onset, sharp pain
Swelling can vary
If you tear the meniscus on the outside (peripheral) which is where there is a good blood supply it will bleed and cause swelling
Swelling can come and go depending on the type of tear
May feel a catch, pop, snap, click, locking
Meniscus- Observation
Capsular Effusion
Could have no effusion but could develop within 48 hours
If you have an ACL and meniscus tear you cannot do closed chain activity
Patellofemoral Injuries
Acute: Traumatic
- Subluxation, Dislocation, Patellar fracture
Chronic
- PFSS, Chondromalacia
Q-Angle
Predisposes athletes to acute and chronic injuries
First line from ASIS to center of patella
Second line from center of patella to tibial tuberosity
Forces at the Tibiofemoral Joint: compression and shearing during daily activities
Forces at the Patellofemoral Joint: Walking, going down stairs, squats, deep squats
A larger q angle increases the lateral pull of the patella in the groove. More likely for the patella to dislocate
Patellar tracking: depends on the direction on if you have weak structures vs strong they might pull in the wrong direction instead of equally
Patellofemoral Pain (anterior knee)
Chronic abnormal forces under the patella
Patellofemoral stress syndrome (PFSS)
Due to poor patellar tracking
Avoid the things that cause it to hurt
Stretch hams, quads ITB, strengthen VMO
Patellofemoral Stress Syndrome
Long term: Osteoarthritis of Patella
Chondromalacia:
Degeneration of the articular surface of the patella
Stages of progression
Localized tenderness under patella
Anterior knee pain
Dislocation: patella has completely slid out of where it sits in the bone
Subluxation: different grades of it but partial displacement of the bone in the joint
Misc Knee Pathologies
Bursitis
Happens in the bursa which are fluid filled sacs
Lie on top of bony structures and slide over each other
Bursa in the Knee:
Suprapatellar
Prepatellar
Infrapatellar
Pes anserine
Most common in the knee are Prepatellar, Pes Anserine, Infrapatellar
Prepatellar: Acute: blow to the knee, Chronic: repeated blows to the knee
Pes Anserine: Friction between Pes tendon and the MCL
Repeated tibial rotation movements
Infrapatellar: friction, direct blow, Chronic: kneeling
Contuse or irritate them because of friction
Contusion: acute
Irritable: chronic
Bursitis Treatment
Compression and protection
A doctor can aspirate it with a needle
Patella Plica Syndrome
Plica is a fold in the synovial lining that can become superficial
Many people have them and are asymptomatic until injured
Acute: direct blow
Chronic: friction as the plica rubs on the medial condyle of femur
Osgood Schlatter Disease
A traction apophysis at the tibial tubercle (Distal)
Very common, typical in prepubescent boys
Due to growth spurts
Bones grow faster than their muscles and tendons lengthen
Where the patellar tendon attaches to the tibia. Causes a chronic inflammation or sometimes a piece of bone comes off
Larsen Johansson Disease
A traction apophysis at the proximal end of the patellar tendon
Still typical in prepubescent boys
Patella Tendonitis (Jumper’s Knee)
Overuse injury due to repetitive activity
Repeated jumping and landing
Happens in basketball and volleyball players typically
Aching pain after activity in the beginning of injury, aching pain during activity as it gets worse
Most likely to happen in an adult (skeletally mature)
IT Band Syndrome
IT Band moves back and forth over the lateral epicondyle when flexing and extending the knee
Due to training problems: running on the track in the same direction. Pushing on outside leg more than inside leg
Running on road: crowned ^ if you run on one side you are pushing more on one leg than the other
To fix this go the opposite way to even things out
Baker’s Cyst:
Swelling in the posterior of the knee in the synovial bursa