every knee must bend mi zucker, md. a dr z lecture

Every KNEE Must Bend

MI Zucker, MD

A dr Z Lecture

On Injuries of the KNEE

The KNEE Series

• Lateral (cross-table)

• Anterior-posterior (AP)

• Obliques: internal/external

• Patella (“sunrise”)

• Notch

Lateral, AP, Obliques

Patella and Notch

• Patella or “sunrise” is tangential• Notch is a bended knee AP

Anatomy

• Lateral

Anatomy

• AP

Anatomy

• Patella

Soft Tissue Swelling

• Loss of tissue planes

Joint Effusion

• Distension of SUPRAPATELLA BURSA

• Normal

Joint Effusion

• NOT predictive of fracture.

• Can be due to ligament, meniscus or bone injury.

Lipohemarthrosis

• IS predictive of fracture: 100%• Need cross-table lateral to see it

Patella Fracture

• Direct blow

• Fragments not very distracted

CAVEAT

• Bipartite patella: developmental variant of the superior-lateral corner, often bilateral

The EXTENSOR APPARATUS

• Quadriceps muscles• Common ext. tendon• Patella and

retinaculum• Patella ligament• Ant. tibia tubercle

Patella Fracture: Indirect

• Fragments are distracted

• ORIF

Extensor Apparatus Injuries

• Common extensor tendon injury

• Patella ligament injury

KID Extensor Injury

• Anterior tibia tubercle: Injury of the PHYSIS

Tibia Plateau Fractures

• Lateral 80%• Medial 10%• Lateral and medial

10%

Tibia Plateau Fractures

• Vertical, with or without depressed articular surface

• Impacted type can be very subtle

Tibia Spine Fracture

• Can occur at any age, but common in kids especially after fall onto flexed knee from bicycle: “Bicycle Fracture”

Segond’s Fracture

• At attachment of lat cap lig to lat margin of tibia

• Same mechanism as ACL injury

• 95% predictive of ACL tear

Collateral Ligament Injuries

• Usually, nonspecific: joint effusion, soft tissue swelling

• Torn lig occasionally calcifies later

Fibula Head Fracture

• Usually, direct blow

• Can be associated with PCL tear

Osteochondral Fracture

• Articular surface of femur, lat aspect of medial condyle

Acute

Stress: osteochondritis dissicans

Distal Femur Fractures

• Big mechanism• Intercondylar,

supracondylar.

• ORIF

Patella Dislocation

Almost always LATERAL

Can fracture edge of

patella/femur

Acute management is closed reduction

Knee Dislocation

• Big mechanism

• Big risk of arterial injury

• So, big emergency!

Tibia-Fibula Fractures

• Serious injuries• Poor blood supply to

tibia, so delayed healing frequent.

• ORIF

Exception: Stress Fracture of Tibia

• Repetitive injury causing microfractures

• Usually, FATIGUE type

• Non-operative management

Toddler’s Fracture

• Child just learning to walk

• Twisting injury• NOT predictive of

child abuse• Non-operative

management

Corner/Bucket Handle Fracture

• Twisting of joint• Intentional injury• Pathognomonic of

child abuse

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