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Flashcards in The Knee Joint & Pathology Deck (26):

What are the menisci?
Where are they attached?
What do they do?

Crescent shaped plates of fibrocartilage
Thicker at the edges
Attached to the inter condylar areas
Attached to joint capsule via coronary ligaments
Anteriorly connected by transverse ligament of the knee
Deepen the surface of articulation
Act as shock absorbers

Good blood supply - peripheral tears are normally repaired


Describe the anterior cruciate ligament

Prevents the femur moving backward on the tibia
Passes posterior and inserts laterally
Weaker of the two
Relatively poor blood supply
Limits hyperextension

The geniculate artery runs through the ACL - so ACL tear leads to arterial rupture - haemoarthrosis - swelling within minutes


Describe the posterior cruciate ligament

Prevents the femur moving anteriorly on the tibia
Passes anteriorly and inserts medially
Stronger of the two
Limits hyperflexion
Main stabiliser in weight bearing flexed knees


Where is the medial collateral ligament attached?

What is its function?

Medial epicondyle of the femur and medial tibia
Valgus stabiliser
Resists external forces to the knee


Where is the lateral collateral ligament attached?

Lateral epicondyle to head of the fibula


What are the other ligaments of the knee joint and what do they do?

Patellar ligament - reinforce anteriorly
Oblique popliteal ligament (extension of the tendon of the semimembranosus) - reinforce posteriorly
Arcuate popliteal ligament - reinforce posteriorly


What is meant by locking the knee in extension?

So it is less effort to stand
The femur rotates medially over the tibia
The knee joint is held in position
To unlock - popliteus helps to rotate the femur laterally


What is meant by the 'unhappy triad'?

ACL tear
Medial ligament tear or sprain
Medial meniscus tear

Due to a twisting injury with valgus force
Most commonly sporting tackle injuries to the side of the knee when the foot is planted on the ground


What is housemaid's knee?

Swelling on the anterior side of the knee due of swelling of the pre-patellar bursa caused by friction between the skin and the patella


What is clergyman's knee?

Inflammation of the infra-patella bursa
Due to friction between the skin and tibia


How can the anterior cruciate ligament be damaged?

Can be torn by hyperextension of the knee joint or by the application of a large force to the back of the knee with the joint partly flexed


How can the posterior cruciate ligament be damaged?

Most common mechanism of damage is dashboard injury
Occurs when the knee is flexed and a large force hits the shins, pushing the tibia posteriorly


What is the blood supply to the knee?

The popliteal artery gives rise to superior and inferior medial genicular arteries, superior and inferior lateral genicular arteries as well as a middle and a descending genicular artery, which all form an anastomosing network around the knee


What happens is a dislocation of the patella?
How is dislocation resisted?

Laterally dislocates
The tendency towards lateral dislocation is normally counter-balanced by the medial part of vastus medialis
Lateral dislocation is also resisted by the more anterior projection of the lateral femoral condyle and over the lateral patellar facet


What type of joint is the knee joint?

What are the articulations?

Synovial hinge

Condyles of the femur
Condyles of the tibia
Patellar surface of the femur
Articular surface of the patella


How can we assess the integrity of the cruciate ligaments?

ACL: anterior draw test
Lachman's test - raise and stabilise the femur over your leg, then try and move the tibia anteriorly and posteriorly

PCL - posterior sag, posterior draw test


How can we assess the integrity of the menisci?

McMurrays test
Medial meniscus - externally rotate leg, apply valgus stress and extend
Lateral meniscus - internally rotate leg, apply varus stress and extend leg


What is the presentation of ACL tears?

What are the investigations and management?

Popping, pain and immediate swelling - common sports injury
X-ray may show Segond fracture (avulsion fracture of the proximal lateral tibia)
Joint aspirate - haemoarthrosis
Physical therapy and lifestyle
ACL reconstruction


What is the presentation of meniscal tears?

What are the investigations and management?

Twisting injury, localising pain with joint line tenderness, popping, catching, locking
X-ray, MRI
Rest, NSAIDs, rehab
Partial meniscectomy
Meniscal repair


What are the neurovasculature complications of meniscal repair surgery?

With lateral repair - possible damage to common fibular nerve
With medial repair - possible damage to saphenous nerve


What are the grades of MCL sprain?

What are the management options?

Grade 1: mild, no loss of integrity - NSAIDs and rest
Grade 2: moderate, incomplete/partial tear, increased joint laxity - consider additional knee brace
Grade 3: severe, complete tear, markedly increased joint laxity, no end point on stress testing - ligament repair/reconstruction


What happens in quadriceps tendon rupture?

Acute pain (possibly on chronic pain)
Tenderness, unable to extend against resistance
Unable to perform straight leg raise


What are the investigations in quadriceps tendon rupture?

What are the management options?

X-ray - patella baja - low lying patella
Knee brace immobilisation
Primary repair with reattachmemt


What happens in patellar tendon rupture?

What are the investigations and management?

Flexed knee eg basketball players jumping and landing
Pain, pop, unable to weight bear
Increased risk with connective tissue disease
Unable to straight leg raise
Patella alba on X-ray
Mx immobilisation, repair and tendon reconstruction


What is meant by the Oxford Knee Score?

Scoring system used to assess severity degree /function for a knee complaint
Patient completes
A higher score is better
Less than 23 suggests disabling disease


What is meant by Osgood-Schlatter's disease?

Tibial tubercle apophysis (irritation/inflammation to apophysis which is an area of growth cartilage where tendons and ligaments will eventually attach to)
Common in children, boys more than girls
Presents with anterior knee pain, especially when kneeling