4. PREDISPOSING CAUSES
• Increased Q angle
• Weakness and laxity of medial quads.
• Tight lateral structures.
• Abnormal insertion of lig. Patella. ( lateral)
• Defective development of lat. Femoral condyle
and flattening of intercondylar groove.
• Maldevelopment of patella.(alta/baja)
• Valgus deformity of knee.
5. CLINICAL FEATURES
• Girls > boys
• Bilateral
• Acute pain & knee stuck in flexion, falls to ground.
• Tenderness medial side of knee.
• Swollen joints- later
• Aspiration- haemarthrosis
6. • Apprehension test(provocative): positive
• A positive J sign—slight lateral subluxation of
the patella as the knee approaches full
extension
• X ray- AP/Lat/ Skyline
• Blumensaat line
• Sulcus angle
• Q angle
• Insall’ s index
19. COMPLICATIONS
• Instabilty of knee.
• Loose bodies due to osteochondral #
• Osteoarthritis- secondary
• Postsurgical
1. Infection
2. stiffness
20. OTHER TYPES
• Congenital dislocation: from birth due to
tight lateral structures. Very rare. Poor
results.
• Habitual dislocation: patella dislocates
every time there is flexion and reduces on
extension.