4. Lower Limb Knee Flashcards
3 bones of the knee joint
- Distal femur
- Proximal tibia
- Patella
Femoropatella joint
• Femoropatella joint – patella and anterior aspect of femur
Distal femur - structure
Lateral and medial epicondyles
Lateral and medial condyles
Intercondylar fossa
Patella surface
Distal femur • Patella surface
of femur –articulates with articular surface of patella
Distal femur- intercondylar fossa
• Intercondylar fossa – between 2 fossa articulate with intercondrial emininets on tibia
Proximal tibia - structures
• Lateral and medial tibial plateau
Tibial tuberosity – large lump of bone at front of tibia
Anterolateral tibial tuberosity (Gerdy)
Proximal tibia
• Lateral and medial tibial plateau
○ Artciulate with condyles of femur superiorly
Between them are intercondylar tuberckes of intercondylar eminence
Proximal tibia - tibial euberosity
• Site of attachment for patella ligament and quadriceps
Proximal tibia - Anterolateral tibial tuberosity (Gerdy)
• Attachment for fascia lata
Patella
Posterior
• Articular surface – articualtes with patells surface of femur (medial and lateral articular surface)
Patella is a sesoimoid bone
= completely encased in tendon
Quadriceps femoris muscle tendon
Quadriceps femoris muscle tendon – comes from surperior aspect covers patella comes put other side is known as patellar ligament and attatches to tubial tuberosity of proximal tibia
5 key points about the knee
- Condyles of distal femur articulate with the plateaus of the proximal tibia
- 2 separate articulations between tibia and femur – medial and lateral femorotibial
- Patellar surface of femur articulates with articular surface of the patella
- Fibular NOT involved in articulation
- Femur epicondyles, tibial tuberosity, tibial intercondylar tubercles – attachment sites for ligaments
3 components of knee stability
- Capsule = weak stability
- Ligaments = main stabilisers
- Muscles = main role is movement secondary role is stability
Without stabilsiers the knee would be unstable due to shape of articualr surfaces
2 layers of knee joint capsule
- Fibrous layer (grey layer)
* Synovial membrane (purple)
Knee joint capsule- fibrous layer
○ Covers exterior portion of the joint
○ Anteriorly it joins patella ligament goes round and posteriorly there is a gap for popliteaus tendon to insert
Knee joint capsule- synovial membrane
○ Inner membrane
○ Dips in middle between articular surfaces to give 2 articular cavities (relevant in knee surgery
Knee joint capsule- between fibrous and synovial layers
sites of attachment for cruciates ligaments – between fibrous and synovial layers
Extra capsular knee ligaments
o Collateral ligaments
o Patellar ligaments
o Oblique & arcuate popliteal ligaments
Intra-capsular knee ligaments
o Cruciate ligaments
o Menisci
Extra-capsular ligaments - lateral aspect
• Fibular collateral ligament
○ Runs from Lateral epicondyle of femur to head of the fibular (attaches to fibular)
○ AKA lateral collateral
• Arcuate popliteal ligament
Extra capsular ligament – medial aspect
Tibial collateral ligament
• Medial epicondyle of femur down to tibia
• 3rd point of attachment to medial meniscus
• Weaker than fibular collateral ligament
Medial patellofemoral ligament
• Medial epichondyle of femur to patella
• Hold aptella in place
Extra capsular ligament – posterior aspect
Oblique popliteal ligament
Arcuate popliteal ligament
Both prevent hyperextension of knee
Collateral ligaments
- Fibular collateral ligament
- tibial collateral ligament
Intra- capsular ligaments – cruciate ligaments (posterior view)
Anterior cruciate ligament (ACL)
• Attatches to anterior aspect of the tibia and runs posteriorly
• Weaker
Posterior cruciate ligament
• Attatches to posterior aspect of tibia runs forwards
* They cross over as cruciate means cross * Prevent anterior and posterior rolling of femur
Cruciate ligaments
Anterior cruciate ligament (ACL)
Attatches to anterior aspect of the tibia and runs anteriorly
Posterior cruciate ligament
• Attatches to posterior aspect of tibia runs forwards
Menisci
Medial meniscus
Lateral meniscus
Transverse genicular ligament joins medial to lateral meniscus and stabilises it
Main role = shock absorption prevent large movements
Medial meniscus
- Larger
- 3 attachment points
- C shaped
- Less mobile – attaches to tibial collateral ligament
Damage to tibial collateral ligament affects medial meniscus and vice versa
Laterall meniscus
- 2 attachment points
- Smaller
- Circular shaped
- Freely moveable
Anterior muscles of knee
- Quadriceps = 4muscles
- Join together ine 1 tendon to give quadriceps tendon, passes over patella becomes patella ligament and attached to tuberal tuberoisty
All muscles extend knee
Quadriceps
○ Rectus femoris (most supericifal)
○ Vastus lateralis
○ Vastus medialis
○ Vastus intermedials (deep to rectus femoris)
Posterior muscles of the knee
• Hamstrings (3 muscles) lateral - medial
○ Attach below onto tibia • All muscles flex the knee
Hamstrings
○ Biceps femoris (2 heads)
○ Semi tendonous
○ Semi membranousis
3 medial muscles of the knee
- Gracilis – hip flexor ?
- Sartorius – hip flexor
- Semitendinosus
Also help in knee extension
2 lateral muscles of the knee
• Iliotibial tract – stabilisation
Popliteus
4 Knee movements
Extension
Flexion
Medial rotation
Lateral rotation
Extension of knee
- Anterior aspect knee
* Quadriceps – listed above
Flexion of knee
- Posterior aspect of thigh
* Hamstrings
Medial rotation of knee
- Semitendinosus and semimembranosus (when flexed)
- Popliteus (when extended)
Gracilis and scartorius
Lateral rotation of the knee
- Biceps femoris (when knee flexed)
* More rotation when knee is flexed, less when knee is fully extended
Bursae
—> bursae = fluid filled sac that acts as a lubricant reduces friction between bone, tendon, muscle etc
• Clinically – bursae can become inflammed – suprapatellabursitius
• Some bursae are continuous with synovial cavity of knee – bursts = septic arthritis
Structures in popliteal fossa
Posterior to anterior
Structures
• Tibial nerve (superficial)
• Popliteal vein
• Popliteal artery (deep)
Popliteal fossa borders
- superior Lateral border = biceps femoris
- Superior medial border = semimembranous and semitendonosus and their tendons
- Inferiorly = borders of gastronemious
- Laterally = lateral head of gastronemus
4 compartments of ey
- Anterior
- Lateral
- Deep posterior
- Superficial posterior
3 superior muscles of the leg
Gastronemius
Soleus
Plantaris
Gastronemius
• Gastronemius (most superifical in postrior compartment )
○ Large muscle with 2 heads lateral and medial that join to form calcaneal tendon
○ More prominent in more vigours movement
Plantaris
• Plantaris muscle – small muscle with long thin tendon, minimal movement, used in proprioception and balance in leg
Calcaneal tendon
• Calcaneal tendon (achilies tendon) lateral and medial head of gastronemius and head of soleus muscle join together to form this
4 Deep posterior muscles of leg
- Tibialis posterior muscle – plantar flex foot or ankle
- Flexor hallucis longus (lateral) - flex the big toe
- Flexor digituorum longus (medially) - flex other 4 toes (digits)
Tibialis posterior muscle
• Tibialis posterior muscle – plantar flex foot or ankle
Flexor hallucis longus (lateral)
• Flexor hallucis longus (lateral) - flex the big toe
Flexor digituorum longus (medially)
• Flexor digituorum longus (medially) - flex other 4 toes (digits)
Popliteus
• Popliteus – posterior aspect of knee (minor role in knee flexion)
Locking mechanism of the knee
- In full extension knee is ‘locked’
- Due to medial rotation of fibia on top tibia – tightens tendon on knee
- Allows you to stand up straight with a while without quadriceps getting tired
Unlocking mechanism of the knee
- During flexion popliteus contracts, rotating tibia laterally, ‘unlocking knee’
- Allows flexion
- Main role of popliteus
Nerves of knee and posterior reg
• Sciatic nerve splits into
○ Tibial nerve and common fibular nerve (common peroneal nerve)
○ Tibial nerve passes through popliteal fossa as most superfiical structure – gives medial sural cutaneous nerve in leg and in the foot it gives medial plantar nerve and lateral plantar nerve
○ common fibular nerve (common peroneal nerve) - spiral round fibia supply anterior portion of leg, but gives of sural communicating branch which joins with medial cutaneous nerve to give sural nerve that supplie lateral aspect of foot
Arteries of knee and postreior leg
- Femoral artery emmerges from adductor hiatus becomes popliteal artery
- Popliteal artery passes through popliteal fossa
- Gives an anterior tibial branch
- Splits into posterior tibial artery and fibular (peroneal) artery
- Posterior artery splits into medial plantar and lateral plantar nerves in the foot
- Fibular (peroneal) artery suplies medial aspect of foot
Periarticular genicular anastomosis -
Veins of the knee and posterior leg
- Small saphenous vein – postrior and superficial on calf of posterior leg,
- Same as arteries and valves
- Fibial peroneal veins
- Popliteal vein through popliteal fossa
Arteries run alongside veins
3 types of traumatic injures of the knee
- Fractures
- Dislocation
- Soft tissue injuries
Fractures
- Femoral shaft fracture
- Distal femoral fractures/IA fractures
- Proximal tibial fractures/Tibiaplateau fractures/Tibial spine fractures
- Patella fracture
- Osteochondral defects
Dislocations
- Knee dislocations
* Patella dislocations
Soft tissue injuries
- Meniscus injuries
- Collateral ligament injuries
- Cruciate ligament injuries
Cortical bone
Cortical bone : withstand compression and shearing forces > tension forces
Physical factors in fractures
Caused by Tension failure (pulled/twisted apart) majority of fractures.
= explosive tension of failure on the convex side and if extends across the entire bone: transverse or oblique fracture
Pediatric fractures
- “Green stick # fractures ” - bone will bend but not break
* NIA – twisting in young child avulsion fracture (tendon to bone) – can be seen in child abuse
Compression fracture
Impacts spongiosa in cancellous bone
• Spongiosa = easier to crush = compression forces crush fracture = compression fracture = impaction
- seen in vertebral body
Buckle fracture
Pediatric - eg.greenstick fracture
• “Buckle” fracture = buckle or impaction of the cortex surrounding the cancellous bone (“torus” fracture) (“tori” Latin for swelling)
6 categories in the description of fracture.
Site
Extent
Configuration
Relationship of fracture fragments to each other
Relationship of fracture fragments to external environment
Complicated or uncomplicated
Site - fracture
• Which site of bone is broken ○ Diaphyseal ○ Metaphyseal ○ Epiphyseal or intra-articular ○ Fracture dislocation
Extent - fracture
- Complete
* Incomplete: hairline, buckle and greenstick
Configuration - shape of fracture
- Transverse
- Oblique
- Spiral
- Communited: more than one fracture line = more than 2 fragments (high energetic traumas)
Relationship of fracture fragments to each other
• Undisplaced
• Displaced: (relation to muscle pull on the fragments)
○ Translated = 2 fragments shifted, not full contact
○ Angulated = angle between proximal and distal fragment
○ Rotated = twisted
○ Distracted = space between 2 bones as muscles pull away
○ Overriding = overlapping
○ Impacted
Relationship of fracture fragments to external environment (skin and soft tissues)
- Closed = bone is not exposed
* Open (Gustillo classification- describe extent of open fracture) = bone is exposed
Complicated or uncomplicated
- Complicated = nerve or blood vessel damage
* Uncomplicated
3 incomplete fractures
hairline, buckle and greenstick
Tibia plateau fracture
= left proximal tibia Intra-articular fracture with lateral and posterior displacement, communited
Mid-shaft femoral fracture
= Complete closed mid-shaft femoral fracture, short oblique, 90% translated and 30 degrees of angulation (apex lateral)
Fracture classification
—> fractures through tibular joints are more complex
Tibeau plateau fractures are classified based on Schatzker tibia plateau classification
Musculature and fractures
Fragments will displace based on actions of the muscles
—> musculature acts as a deforming force after fracture
Proximal fragment
-abducted
• gluteus medius and minimus
• abduct as they insert on greater trochanter
-flexed
• iliopsoas flexes fragment as it inserts on lesser trochanter
Distal segment
varus
• adductors inserting on medial aspect of distal femur
-extension
• gastrocnemius attaches on distal aspect of posterior femur
Diagnosis of traumatic knee injuries
- History – mechanism of injury
- Examination:
- Inspection, skin (open/closed)
- Palpation – check for vascular compromise
- Associated injuries (neurovascular, compartmentΣ - compartment syndrome)
- Diagnostic imaging (Immobilization of patient to minimise pain!)
- X-rays (entire length of the bone) AP +LAT/Oblique
- CT/MRI
3 patella injuries
- Fracture
- Dislocation
- Peripatellar bursitis
Fracture of the patella
- 1% bony injuries
- direct hit/ interruption of extensor mechanism
- Straight leg raise test = patient can’t raise their leg up
- Description of fracture
- treatment = R/ Closed/open reduction internal fixation
3 things that Dislocation of the patella causes
- Traumatic
- Congenital = abnormal structures round the knee cap
- Hypermobility= marfans, down syndrome related disease
Multifactorial biomechanical cause of dislocation Stabilizers:
3 kinds
- Muscles (most important is medial vestus)
- Bony(rotation/malalignment/articular surface)
- ligaments – medial patella femoral ligament
Q angle and patella
- Bigger q angle = more forces on kneecap to be dislocated
* 2 lines anterior superior iliac spine to midpoint of patella and midpoint of patella to tibial tubercal
Traumatic dislocation of the patella
- High incidence of associated injuries (20%) : Imaging
- High recurrence rate (50%)
Complete dislocation – no contact between patella and trochlear groove
3 types of Soft tissue injury of the knee
- Valgus/varus stress: Collateral ligaments damaged (knocked knee)
- Anterior/posterior stress: Cruciate ligaments affected (some rotation needed for them to be fully pulled)
- Rotation disturbance + stress/axial loading: meniscal injury (+/- ACL)
Collateral ligaments -2
Medial collateral ligament
Lateral collateral ligament
• Valgus/varus stress: Collateral ligaments damaged
- Pain, decreased ROM(limited extension and deep flexion), swelling/hemarthrosis
- treatment = Conservative R/ RICE; hinged brace, PT (physiotherapy) to stabalise knee
- Stieda-Pelligrini syndrome – bony abnormality, calcification of insertion
- LCL more instability problems – when repturred need orthopeodic referal and management
Soft tissue injury of the knee- Anterior Cruciate ligament injury (ACL injury)
Epidemiology
- Non-contact injury (stance leg (F); kicking leg (M))/contact injury
- Associated with (lateral) meniscus injury (≈ 50%)
- Female > male (multifactorial) - more common in female than male due to hormones
Mechanism of ACL injury:
- Deceleration, single leg stance = athlete stands on one leg
- hip ADD + IR
- Knee in slight flexion
- Tibial torsion
ACL injury treatment
- Conservative (if person isn’t too physical): Lifestyle adjustments Physiotherapy
- Operative (more athletic patient): ACL reconstruction Autograft/ (patient own tendon)allograft (donor tendon) post-op rehabilitation program
- Long-term complication: OA osteoarthritis , knees will never be the same
Posterior cruciate ligament injury
Diagnosis
- Sag sign = tibia falls distal towards femur, divot on lateral aspect of knee
- Posterior drawer test = bring knee forward instead of backward
Meniscal injury
- miniscus = Fibrocartilage structur, half moon shape
- Protection/mechanical role
- Medial tears > lateral tears (ACL)
- Degenerative tears (PH-MM posterior horn of medial miniscus more often involved)
Meniscal injury
Symptoms
- Pain joint line,
- locking,
- swelling(rare)
Meniscal injury - treatment
TREATMENT = PT (physiotherapy) versus Surgery
• Surgey depends on injury – partial resectioniong or suturing surgery
A’scopic partial resection or suturing Discoid meniscus (development derranged in embryogenesis, central part of miniscus did not disolve to give moon shape)
• Normal, incomplete, complete miniscus (complee miniscus has no moon shape)
Discoidd meniscus
- No half moon shape
* Complete miniscus
4 common knee problems
- Septic arthritis
- Inflammatory arthritis (rheumatologic, haemophilic, metabolic disease)
- Osteoarthritis
- Overuse injuries:
Overuse injuries - examples
- (Tendinopathies)
- (Osteochondritis dissecans or osteochondral defects)
- Apophysitis (Osgood-Schlatter disease, Sinding-Larson-Johansson)
- Peri-patellar bursitis
Septic arthritis - treatment
Deal with urgently
• Joint aspiration – to identify causative bacteria
• and (a’scopic) wash-out
• IV AB – intravenous antibiotics
• urgent treatment < septic shock, joint damage
Prepatellar bursitis
- Inflammation of bursa, infront of patella = it is a fluid filled pocket protecting rubbing against bone
- Inflammed when there is constant load on bursa
Prepatellar bursitis - treatment
• Rest, compression NSAID avoid causing activity surgical resection(rare)
Rheumatoid arthritis
Inflammatory disease
– Systemic Autoimmune disease
– Genetic predisposed
– Most common form of inflammatory arthritis – 3% women – 1% men
––> Auto-immune response attacks soft tissue > cartilage > bone (destructive)
– Tenosynovitis (inflammation of tendon and tendon sheaths), synovitis, joint subluxation(destruction of joints)
Rheumatoid arthritis - treatment
Inflammatory disease
– Medication to balance decrease inflammation
• Removal swollen soft tissue with surgery
• Total Knee Replacement
Osteoarthritis – degernative arthritis
Inflammatory disease
= progressive loss of articular cartilage due to
– Traumatic injuries
– Work load/repetitive bending and extending
– Obesity
– Mechanical malalignment
Clinical:
Limited ADL/ROM
Pain at rest and at night
Swelling and stiffness – localized on the joint
Osgood-Schlätter disease
- Irregularity at tubular tuberosity
* Rest, ice, no stretching assess sports schedule and adjust self-limiting disease
Rice
RICE – rest ice compression elevation
Structures of pes anserinus
Tendon of sartorious
Gracilis
Semitendinosous muscles
Patellar tap
If knee effusion is present, kneecap will move down and tap bone beneath
Unhappy triad of injuries
Medial collateral ligament
Anterior cruciate ligament
Medial meniscus
Medial meniscus is most commonly torn because
It is attached to the medial collateral ligament
Meniscal tears heal poorly due to
Limited blood supply to meniscus
Simmond’s test
→ absence of foot plantarflexion on calf compression
Test for evaluating achilles tendon rupture
Common masses in popliteal fossa
Meniscal cyst
Synovial cyst
Ganglionic cyst
Baker ‘s / popliteal cyst
Fluid filled swelling at the back of the knee
Housemaids knee - suprapatellar bursitis
Inflammation of bursa in front of the knee
Clergyman’s knee - suprapatellar bursitis
Irritation/inflammation of the bursa
Infected suprapatellar bursitis
Sepsis
Palpation worksheet D
