orthopaedics: knee Flashcards
what does the knee joint consist of
medial and lateral compartments of tibiofemoral joint, patellofemoral joint
what type of hyaline is inside the synovial knee joint
hyaline
what part of the body has the thickest hyaline cartilage
retropatellar surface
what are menisci
fibrocartilaginous cartilage inbetween tibiofemoral joint (x2), they are shock absorbers
which meniscus is more mobile
lateral more mobile, medial fixed
what is the function of the anterior cruciate ligament (ACL)
prevents tibia rotating
what is the function of the posterior cruciate ligament (PCL)
prevents hyperextension and translation of the femur
what do the medial and lateral collateral ligaments (MCL and LCL) do
MCL resist valgus forces, LCL resists varus forces
what are early OA risk factors for the knee (5)
meniscal tears, ligament injuries (esp ACL), abnormal alignment, inflam arthritis, hobbies/ occupation
what are the criteria for a knee replacement from OA
substantial pain and disability with no conservative treatment working
what are risks of knee replacement
infection, thrombosis, unexplained pain after TKR
who gets and what causes meniscal tears
young people playing sport - twisting force on loaded knee
what are symptoms of meniscal tears
localised pain in medial or lateral joint line, effusion that develops NEXT day, pain, locking (cant straighten knee), positive steinmanns test
what is more common medial or lateral meniscal tears
medial 10x more common
what type of meniscal tears can occur
longitudinal, radial, oblique, horizontal, flap, degenerative
what are bucket handle tears
large longitudinal tears where meniscal fragment flips out and is displaced
what is a key feature of bucket handle tears
knee locks and cannot fully extend from mechanical obstruction - 15 degree extension
how do you manage bucket handle tears
urgent arthroscopic repair
what are degenerate meniscal tears
complex patterns
who gets degenerate meniscal tears
elderly, common first stage of OA, spontaneous or mild injury
how do you manage degenerate meniscal tears
steroid injection
what feature of menisci leads to poor healing and what else contributes to poor healing
poor blood supply - elderly and older injuries
what is gold standard investigations of meniscal tears
MRI
what is the criteria for a meniscal repair
longitudinal repair in outer 1/3, recent, young patient (need 3/3)
what is involved in a meniscal repair
stitching meniscus to it’s bed, extensive rehab (90% not suitable)
when would an arthroscopic partial meniscectomy be done
mechanical and acute tears
what causes ACL ruptures
high rotational force: rotating body landing on planted foot - skiing, rugby, football
what are symptoms and signs of ACL ruptures
pop usually heard/ felt, haemoarthrisis within an hour, deep pain in knee
what is a symptom of chronic ACL rupture
when turning on planted foot gives way, tibia translocated forward
what is favoured in ACL management
reconstruction > repair
who are general ACL reconstruction candidates
professional sportsmen, failed phsyio, if injury from low impact injury
what is involved in ACL reconstruction surgery
tendon graft passed through tibial and femoral tunnel, attached to normal ACL attachment sites on bone. then intense rehab
describe PCL ruptures (4 points)
not common by itself, direct blow to ant tibia, bruising and knee pain, tibia translocated ant
what are symptoms of MCL tears
laxity, pain on valgus stress, tenderness on origin and insertion of ligaments
how do you manage acute MCL tears
normally good healing, hinged knee brace
how do you manage chronic MCL tears
MCL tightening and reconstruction with a tendon graft
when do LCL ruptures occur
uncommon alone - combo with PCL and ACL
what is commonly injured in LCL ruptures
peroneal nerve
what management is done in complete LCL tears
urgent surgery –> later reconstruction
what causes a complete knee dislocation
high degree of forces can rupture all 4 ligaments (ACL, PCL, MCL, LCL)
what are risks of total knee dislocation
thrombosis, popliteal artery damage, compartment syndrome
how do you manage a total knee dislocation
emergency, X ray, vascular surgery assessment, stent or bypass, multi-ligament reconstruction
what does the extensor knee mechanism consist of (5)
tibial tuberosity, patellar tendon, patella, quadriceps tendon, quadriceps muscles
how to extensor mechanism ruptures occur
fast contractile forces eg weightlifting, fall, degenerative tendon
which age group get patella tendon ruptures vs quadriceps tendon ruptures
patella = young < 40 quadriceps = old
what are risk factors for extensor mechanism ruptures (5)
tendonitis, chronic steroid use, diabetes, RA, CKD
what drugs can cause tendonitis
quinolone ABs eg ciprofloxacin
how do you diagnose extensor mechanism ruptures
strait leg test, obvious gap, USS in overweight patient
how do you manage extensor mechanism ruptures
surgery for complete/ large tears, reattachment of tendon to patella
what is patellofemoral dysfunction
disorder of patellofemoral articulation
what is patellofemoral dysfunction associated with (3)
chondromalacia patellae, adolescent ant knee pain, lateral patellar compression syndrome
what are signs and symptoms of patellofemoral dysfunction
ant knee pain, worse downhill, grinding sensation, pseudo-locking after prolonged sitting
how do you manage patellofemoral dysfunction
PHYSIO, taping, surgery as a last resort
what can predispose patellar dislocations
ligament laxity, female, shallow groove, genu valum, femoral neck anteverion, high riding patella
