When the foot is on the ground the lower portion of FEMUR MEDIALLY ROTATES over the TIBIA at the end of EXTENSION and the knee is LOCKED; whereas at the beginning of FLEXION the FEMUR rotates LATERALLY over the TIBIA and the knee is UNLOCKED.
This makes the knee joint THE MOST ECONOMICAL joint of our body
LOCKING: Quadriceps Femoris
UNLOCKING : Popliteus
BLOOD AND NERVOUS SUPPLY
5 genicular br. of popliteal artery
Descending genicular br. of femoral artery
Descending Br. of lat. Circumflex femoral artery
2 recurrent br. of anterior tibial artery
Circumflex fibular br. of posterior tibial artery
Common Fibular nerve
Small flap of inner rim or whole of inner rim may tear.
Softening of menisci with advancing age.
Forceful twisting injury.
CRUCIATE LIGAMENT TEAR
ACL TEAR : by twisting force on a semi flexed knee.
Diagnosis:Anterior drawer test
PCL TEAR : when ant. aspect of tibia is struck with the knee semi flexed so as to free tibia backwards on femur .
Diagnosis: Posterior drawer test
Non operative : Robert Jones bandage
Operative :repair of ligament or reconstruction
COLLATERAL LIGAMENT TEAR
MEDIAL COLLATERAL LIGAMENT TEAR
By application of strong VALGUS force (abduction)
Detaches from its femoral attachment.
Symptoms: pain & swelling on the medial side
Tests: VALGUS stress + 30΄ knee flexion
LATERAL COLLATERAL LIGAMENT TEAR
By application of strong VARUS force (adduction)
Detaches from its fibular attachment.
Symptoms: pain & swelling on lateral side
Tests: VARUS stress + 30΄ knee flexion
KNEE REPLACEMENT SURGERY
In this the parts of bone that rub together are RESURFACED with metal and plastic implants.
U shaped femoral component
Tibial base plate
Plastic spacer/ Articulating surface
HEAL UP TIME:6 weeks after surgery
STATS: Knee replacement is a routine surgery performed on over 600000 people worldwide every year
KNEE JOINT DISLOCATION
Lateral dislocation of patella is common
Mc-Murray’s & Apley’s tests are performed
CRUCIATE AND COLLATERAL LIGAMENT TEAR
Lachman’s test, anterior and posterior drawers test for cruciate
Valgus & Varus force for collateral
FRACTURE OF PATELLA
Two types: TRANSVERSE fracture & STELLATE fracture
ARTHROSCOPIC PROCEDURES IN TREATMENT
Repair of knee, repair of ligaments, knee replacements and revisions of knee replacements Total Number Knee Procedures* Total Number Total Knee Replacements 2005 311,000 2005 209,000 2004 289,000 2004 179,000 2003 282,000 2003 167,000 2002 287,000 2002 160,000 2001 234,000 2001 129,000
2006-Total Knee Replacements Age Percent 18 - 44 2.8 45 - 64 24.6 65 - 74 43.3 75 - 84 26.7 85-older 2.9 Average age 66.6 years