Disorders Of The Knee Flashcards
Standard X-ray series for knee
Anterior posterior
Lateral
Patella axial (‘skyline’)
Femoral shaft fracture cause
Young/healthy = High velocity trauma:
falls from height
Road traffic collisions
Older:
Osteoporitic bones/metastases/bone lesions = falling over
Fragment actions femoral shaft
Proximal - abducted (gluteus medius and minimus) and flexed (iliopsoas)
Distal: adducted (adductor magnus, gracilis) and extended (gastrocnemius)
Femoral shaft fracture complications
1500ml of blood loss per fracture
=Hypovolaemic shock
Femoral shaft treatment
Surgical fixation
Distal femoral fractures cause
Younger: high energy sporting injury (lots of displacement of fragments)
Elderly: fall from standing
Artery damage in distal femoral fractures
Popliteal artery - only if signnificant displacement
Assess neurovascular status of limb
Tibial plataeu fracture cause
High energy injuries
Axial (top to bottom) loaded with abnormal varus/valgus angulation
Tibial plataeu fractures affect
Articulating surface of the tibia within the knee joint
Types of tibial plateau fractures
Unicondylar - one condyle
Bicondylar - both tibial condyles
Most common tibial plateau fracture
Lateral tibial condyle
Post problems with tibial plateau fractures
Articular cartilage damaged (fracture fragments)
Post traumatic osteoarthititis in joint
What can tibial plataue fractures be associated with?
Meniscal tears
Anterior cruciate ligament (ACL) injuries
Patellar fractures causes
Direct impact (knee against dashboard)
Eccentic contraction of quadriceps (muscle contracting but joint extending)
Examination of patellar fractures
Palpable defect
Haemoarthrosis (blood in joint)
How do you know if extensor mechanism is affected in patellar fracture?
Patella is split distal to insertion of quadriceps tendon
Unable to perform straight leg raise (flexion of hip while keeping leg extended)
Displaced patellar treatment
Reduction and Surgical fixation
Undisplaced patellar fracture treatment
Protection while healing
Splinting and using crutches
(No surgical fixation)
Abnormalities in patella anatomy
Bipartite (two parts of patella)
May be mistaken as a patellar fracture but IS NOT
(Failure of union of secondary ossification centre)
Patellar dislocation why
Q angle between pull of quadriceps tendon and patellar ligament = lateral dislocation (ASIS to patella and patella to tibial tuberosity)
Usually held in place via vastus medialis fibres (vastus medialis obliquus)
Patellar dislocation cause
Trauma - twisting in slight flexion or direct blow
Athlectic teenagers most affected (sudden direction change - internal rotation)
Factors predispose patella dislocation
Ligamentous laxity
Weakness of quadriceps (especially Vastus medialis)
Shallow patellofemoral groove (flat lateral lip)
Long patellar ligament
previous dislocation
Treament patella dislocation
Extending knee manually
Manually reducing patella
Immobilisation while healing
Physiotherapy to strenghthen vastus medialis
Meniscal injuries cause
Most common
Sudden twisting of weight bearing knee, high degree of flexion
Symptoms/signs meniscal injury
Knee clicking, catching, locking (cant fully extend due to foreign body in joint)
Pain - localised to joint line
Giving way sensation
Menisci injury swelling?
Swelling may be delayed
Reactive effusion or not at all
(avascular menisci except at periphery)
What is acutie haemoarthrosis a sign of in menisci injury?
RARE
Indicates tear in peripheral vascular aspect
Or injury to Anterior cruciate ligament
What is chronic effusion (increased synovial fluid) a sign of?
Synovitis (inflammation of synovial membrane) in menisci injury
Menisci injury signs and symptoms
Locking, reduced motion from loose meniscal fragments between articulating surfaces
Treatment of menisci injuries
Acute tears - surgically (menisectomy or repair)
Chronic degenerative - conservative managemet
Collateral ligament injury causes
Sporting - football
Acute varus/valgus strain