KNEE Flashcards
What type of joint is the knee joint?
Hinge type synovial joint
What forms the knee joint?
Distal femur, proximal tibia and patella
What are the 2 articulating surfaces in the knee joint?
Tibiofemoral - medial and lateral condyles of femur articulate with tibial condyles
Patellofemoral - anterior aspect of distal femur articulates with patella
Blood supply to the knee joint?
Genicular anastamoses around the knee - supplied by genicular branches of the femoral and popliteal arteries
Nerve supply to the knee?
Femoral, tibial and common fibular nerves - Hilton’s law states that a joint tends to be innervated by a branch of a motor nerve which also supplies a muscle extending and acting across the joint
What are the menisci in the knee?
These are 2 C-shaped fibrocartilage rings located within the knee joint to deepen the articular surface of the tibia and act as a shock absorbed due to increasing the SA.
Attachments of the medial meniscus?
Attached at both ends to the intercondylar area of the tibia
Fixed to the medial collateral ligaments and the joint capsule
attachments of lateral meniscus?
Attached to the intercondylar area of the tibia
No other attachments - smaller than medial meniscus and more mobile
What are bursae?
Sac-like structures containing small amounts of synovial lucid
Functions to decrease friction between tendons, bones and skin during movement
Bursae found in the knee?
Suprapatellar bursa
Prepatellar bursa
Infrapatellar bursa
Semimembranosus bursa
Where is the suprapatellar bursa located?
Between the quadriceps femoris and femur
Where is the prepatellar bursa located?
Between the apex of the patella and the skin
Where is the infrapatellar bursa located?
2- the deep bursa lies between the tibia and patella ligaments, and the superficial bursa lies between the patella ligament and the skin
Where is the semimembranosus bursa located?
Posterior to the knee joint between semimembranosus muscle and medial head of the gastrocnemius
What are the major ligaments in the knee joint?
Patella ligament
Medial and lateral collateral ligaments
Anterior and posterior cruciate ligaments
What is the patellar ligament?
Continuation of the quadriceps femoris tendon distal to the patella
Attaches to the tibial tuberosity
Function of the collateral ligaments in the knee joint?
To stabilise the hinge motion of the knee, preventing excessive medial or lateral movement
Where is the medial collateral ligament?
A wide, flat ligament found on the medial side of the joint
Proximal LH it attaches to the medial epicondyle of the femur and dismally it attaches to the medial condyle of the tibia
Where is the lateral collateral ligament?
Thin and rounder than medial ligament
Attaches proximaly to the lateral epicondyle of the femur and distantly to a depression on the lateral surface of the fibular head
Where is the anterior cruciate ligament?
Attaches at the anterior intercondylar region of the tibia where it blends with the medial meniscus
Ascends posteriorly to attach to the femur in the intercondylar fossa
Function of anterior cruciate ligament?
Prevents anterior dislocation of the tibia on the femur
Where is the posterior cruciate ligament?
Attaches at the posterior intercondylar region of the tibia and ascends anteriorly to attach to the anteromedial femoral condyle
Function of the posterior cruciate ligament?
Prevents posterior dislocation of the tibia on the femur
Movements of the knee joint?
Extension - produced by quadriceps femoris
Flexion - produced by hamstrings, gracilis, sartorius and popliteus
Lateral rotation (only when knee is flexed) - produced by biceps femoris
Medial rotation (only when knee is flexed) - produced by semimembranosus, semitendinosus, gracilis, sartorius and popliteus
What is chondromalacia patellae?
Aka patellofemoral pain syndrome
One of the most common causes of pain at the front of the knee due to overloading of the front of the knee, behind the kneecap
Who is chondromalacia patellae most common in?
Teenagers or young adults
Sports involving running and jumping
Symptoms of chondromalacia patellae?
Unilteral or bilateral anterior knee pain behind the patella - aching, gradul onset, aggravated by stairs/squatting/running/long periods of sitting
Sensation of instability
Diagnosing chondromalacia patellae?
Clinical diagnosis
Management of chondromalacia patellae
PT
Structured exercise programme
Presentation of osteoarthritis in the knee?
Activity related, persistent pain
Stiffness in the morning or after inactivity <30 mins
Impaired function
Crepitus and swelling
Painful or restricted movement
Bony enlargement
Referred pain to the knee causes?
Children:
SUFE
Septic arthritis hip
Transient synovitis hip
Perthes disease
Juvenile idiopathic arthritis hip
Adults:
OA od hip
Lumbar radiculopathy
Who does Osgood-Schlatter disease typically affect?
10-15 year olds
More common in males
Sporty teenagers
What is Osgood-Schlatter disease?
Osteochondrosis with traction apophysitis affecting the extensor mechanism of the knee
(Inflammation at tibial tubersotiy where patella ligament inserts)
Pathophysiology of Osgood-Schlatter disease?
Multiple minor avulsion fractures occur -> growth of tibial tuberosity forming a lump -> inflammation causes pain
Presentation of Osgood-Schlatter disease?
Unilateral gradul onset knee pain during adolescence localised to tibial tubersotiy
Relived by rest, worse with activity pressure and resisted knee extension
Prognosis Osgood-Schlatter disease?
Symptoms will fully resolve over time
Pt left with hard bony lump on knee
Complication of Osgood-Schlatter disease?
Rare - complete avulsion fracture = tibial tubersit separated from tibia (requires surgery)
Management of Osgood-Schlatter disease?
Reduce physical activity, ICE, NSAIDs
Physio and stretching can be used to improve function once Sx settle
Most common bursitis in the knee?
Prepatellar bursitis
Causes of bursitis?
Acute - trauma, infection, gout
Chronic - inflammatory arthropathies, repetitive pressure, overuse
Symptoms of pre-patellar bursitis?
Anterior knee swelling and pain with direct pressure/activity
May be a history of preceding trauma/pressure or bursal disease
Associated with more upright kneeling than infrapatellar bursitis
Clergyman’s knee vs housemaids knee?
Clergyman’s - infrapateller bursitis - associated with kneeling
Housemaids knee - prepatellar bursitis - associated with more upright kneeling
Presentation of gout in the knee?
Acute onset severe pain, swelling and tenderness of the joint
Tophi may be present
Presentation of septic arthritis of the knee?
Acute onset hot, swollen, tender knee joint with restriction of movement
May be systemically unwell
What typically causes meniscal tears?
Young patients - sports
Older pt - minor twisting movements in association with degenerative process
Presentation of meniscal tear?
May be a “pop”
locking/catching knees particuarly on twisting or squatting, knees giving way
Pain worst on straightening knee, swelling that is often delayed, stiffness, restricted ROM,
Joint line tenderness, loss of full extension, palpable/audible clicking
Test for meniscal tears?
Thessaly’s test - weight bearing at 20 degrees of knee flexion, patient supported by doctor, postive if pain on twisting knee
What are the Ottawa knee rules?
Rules to determine whether a pt requires an XR of the knee after an acute knee injury to look for a fracture
The Ottawa knee rules state that a patient requires a knee x-ray if any of the following are present:
Age 55 or above
Patella tenderness (with no tenderness elsewhere)
Fibular head tenderness
Cannot flex the knee to 90 degrees
Cannot weight bear (cannot take 4 steps – limping steps still count)
Diagnosing a meniscal tear?
MRI is first line
Arthroscopy is gold standard - can also repair or remove damaged sections
Management of meniscal tears?
Conservative - POLICE
PT
Surgery - arthroscopy may be required to repair meniscus or resection the affected portion (but this often results in OA)
Borers of the popliteal fossa?
Semimembranosus and semitendinosus tendons (superior and medial)
Biceps femoris tendon (superior and lateral)
Medial head of the gastrocnemius (inferior and medial)
Lateral head of the gastrocnemius (inferior and lateral)
What are baker’s cysts?
A fluid-filled sac in the popliteal fossa causing a lump
Not a true cyst but rather a distension of the gastrocnemius-semimemembranosus bursa
Primary vs secondary baker’s cyst?
Primary - idiopathic - typically in children
Secondary - have an underlying condition e.g. OA in adults, meniscal tears, knee injuries, RA
Presentation of baker’s cyst?
Popliteal swelling
Posterior knee aching or stiffness/restricted ROM
Pain, erythema and swelling if ruptured
What is Foucher’s sign?
In bakers cyst - On examination, the lump will be most apparent when the patient stands with their knees fully extended. The lump will get smaller or disappear when the knee is flexed to 45 degrees
Main DDx for a ruptured baker’s cyst?
DVT
Investigation for baker’s cyst?
USS is fist line - also rules out a DVT
Management of a baker’s cyst?
If asymptomatic - no Tx
POLICE + PT + US-guided aspiration or steroid injections
Surgical manament can be done to treat underlying knee pathology contributing to the cyst e.g. meniscal tears
Who does patellar tendinitis most commonly occur in?
Athletes involved in jumping e.g. basketball
Teenage boys during a growth spurt
Symptoms of patellar tendinitis?
Chronic anterior knee pain aggravated by running, walking downstairs and jumping
Stiffness
Tender patellar tendon
Pain reproduced by resisted knee extension
Management of patellar tendinopathy?
POLICE + NSAIDs
PT
What is osteochondritis dissecans?
A relatively common, idiopathic pathological process affecting the subchondral bone (most commonly in the knee) causing secondary effects/cracks in the articular catilage
May progress to degenerative changes if untreated
Who does osteochondritis dissecans typically affect?
Children and young adults
Presentation of osteochondritis dissecans?
Typically unilateral, vague knee pain and swelling, typically after exercise
Knee catching, locking and giving way
Feeling a painful cluck on flexion or extension of the knee
May have joint effusion and tenderness on palpation of the articular cartilage of the medial femoral condyle when knee is flexed
What is Wilson’s sign?
A sign to detect medial condyle lesion in osteochondritis dissecans
with the knee at 90° flexion and tibia internally rotated, the gradual extension of the joint leads to pain at about 30°, external rotation of the tibia at this point relieves the pain
Imaging for osteochondritis dissecans and what you would expect to see?
XR of both knees- subchondral crescent sign or loose bodies
Management of osteochondritis dissecans?
Initial management conservative if stable
Arthroscopy with surgical intervention may be done if defects of artiuclar cartilage
Who does patellar subluxation most commonly occur in?
Teenage girls
Presentation of patellar subluxation?
Recurrent episodes of feeling the knee may give way
May have - Anterior knee pain, locking, catching, recurrent mild swelling
Tenderness over medial patellofemoral ligament, positive patellar apprehension test
What is iliotibial band syndrome?
Common cause of lateral knee pain in athletes
Inflammation where there is friction between the iliotibial band and the lateral epicondyle of the femur
Who is illiotibial band syndrome most common in?
Runners - 1 in 10
Activities with repetitive knee flexion e.g. cycles
Symptoms of illiotibial band syndrome?
Lateral knee pain and tenderness 2-3cm above lateral joint line aggravated by activity - at first occurs late in or after completion of activity but as it progresses it will occur earlier during the activity
Clinking sound may occur during exam
Management of illiotibial band syndrome?
activity modification and iliotibial band stretches
if not improving then physiotherapy referral
Medical term for growing pains?
Benign idiopathic nocturnal limb pains of childhood
Who do growing pains typically occur in?
Girls and boys 3-12 YO
Presentation of ‘growing pains’?
Poorly localised aches and pains in lower limbs - usually calves, shins, anterior thighs, popliteal fossa
Bilateral and symmetrical
Only occur at night
What is a bipartite patella?
A cognieital condition caused by failure of the patella to fuse
Commonly asymptomatic and found incidentally
Sometimes can cause anterior knee pain during adolescence related to repetitive/rigorous sporting
What are plicae?
Embryonic membranous remnants in the knee that may become inflamed and impinged
What are the 2 types of fractured patella?
Nondisplaced kneecap fractures occur when the patella is broken but hasn’t moved out of place.
In displaced patella fractures, the patella is broken and the pieces of bone have moved out of place = avulsion fracture
What are tibial plateau fractures?
A fracture in the tibial plateau (top of tibia)
Who do tibial plateau fractures more commonly occur in?
Elderly
Or following significant trauma in the young
Mechanism for a tibial plateau fracture?
knee forced into valgus or varus, but the knee fractures before the ligaments rupture
Classification for tibial plateau fractures?
Schatzker classification system
Presentation of knee fracture?
MOA - direct trauma or fall
Unable to weight bear
Joint deformity or swelling
Severe pain on movement and limited movement
Neurovascular damage may occur
What typically causes an ACL injury?
Twisting injury to a bent knee e.g. in sports, sudden deceleration, sudden change in direction, forceful hyperextension
Presenation of ACL injury?
Sudden painful popping sensation
Significant rapid swelling 1-2 hours
Inability to return to full activity
Instability to knee joint and knee can buckle - as soon as they attempt to turn the knee will collapses (much more prominent than in PCL tears)
Why does ACL injury cause rapid joint swelling?
The ACL has a blood vessel within the ligament that is torn t the time of injury, causing this hemarthrosis.
Tests for ACL injury?
Anterior drawer test - tibia will move an excessive distance anteriorly
Lachlan test
Management of a ruptured ACL?
Conservative measures
Crutches and knee braces to protect the knee whilst mobilising
Intense PT
Arthroscopic surgery is usually required to form a new ligament - uses grafts from other ligaments
Poor healing due to no blood supply to this ligament
Investigation for ACL rupture?
MRI first line to diagnose
Arthroscopy is gold standard
Mechanism for a ruptured posterior cruciate ligament?
Hyperextension injuries
Direct blow to the front of the proximal tibia with knee in flexion e.g. RTA dashboard injury or sports injury
Presentation of PCL rupture?
May be relatively asymptomatic immediately after
Posterior pain especially when kneeling or anterior pain if chronic PCL injury
Mild effusion and reduced range of knee flexion
Posterior drawer test and posterior sag test may be positive
Injury is commonly associated with posterolateral corner injury
Management of PCL injury?
POLICE
PT - most recover with this
Surgery may be needed
Mechanism of injury for a patellar dislocation?
Direct blow to the medial or lateral aspect of the knee
Symptoms of patellar dislocation?
Patella may be lying medial or lateral i.e. clearly diacloated
Hate swelling
Tenderness along medial edge of patella
Positive apprehension test
Spontaneous relocation often occurs but some present to doctors still dislocated
What age do quadriceps and patellar tendon rupture typically occur?
Quadriceps rupture - people >45
Patellar rupture - people <45
Presentation of a quadriceps or patellar tendon rupture?
Usually occurs during sporting activity or after a fall, but can also occur spontaneously owing to underlying disease.
Sudden onset of anterior knee pain.
Inability to straight leg raise or extend the knee.
Change in height of the patella. There is usually visible deformity with the patella migrated proximally in patellar tendon rupture, and distally in quadriceps tendon rupture.
A palpable gap in the patellar or quadriceps tendon
What is the unhappy triad?
Aka a blown knee
An injury to the ACL, medial collateral ligament and meniscus
Often sustained when a lateral force impacts the knee whilst the foot is fixed on the ground e.g. football, rugby, motocross
Causes pain, stiffness, swelling, catching/locking of the knee, instability and inability to do full ROM
What is Hemarthrosis?
Articular bleeding
Occurs after an injury or in bleeding disorders e.g. haemophilia or on warfarin
Caused by pain, swelling and decreased ROM
What is a knee strain?
An injury in the knee that occurs when a tendon or muscle stretches or tears
It’s often due to overuse e.g. lifting heavy weight or injury
Symptoms of a knee strain?
Cramping in the muscles around the knee - feels as if you have been kicked
Spasms in the muscles
Swelling
Bruising
Difficult with moving the muscles
What is a sprained knee?
An injury to 1 or more ligaments from a stretch or tear i..e ACL, PCL, MCL and LCL
Symptoms of a knee sprain?
Pain
Swelling
Difficulty weight bearing
Pain with ROM
