distal femur fractures mark lee, m.d. - coa · up to 32% healing problems in distal femur ......

Distal Femur Fractures

Mark Lee, M.D.

Overview

The basics New fixation concepts New implants

Know the shape

Anatomy Condyles project posteriorly

Anterior half of the condyles

Too posterior

Too Posterior

Medialization of condyles:

“Golf club” Hockey stick deformity Posterior condyles flare

Distal Femur is a trapezoid

1. Over-penetration medially

2. Anterolateral slope

Femoral Axis LDFA

–Anatomic Axis and articular surface

Mechanical axis

Femoral head ankle

Don’t miss the Hoffa

Understanding the Fracture Imaging is essential

• Femur • Knee • CT scan

Classification A-type: Extra-articular

B-type: involves one

condyle

C-type: involves both condyles

Coronal fracture = 38% (Nork, et al. JBJSA 2005)

Don’t Miss

Pick the right exposure and implant

A type fractures

• Plate with angular stability

• IM nail

B-Type Fractures • ORIF

• Absolute stability

• Screws

• Locking not required

C-Type Fractures Anatomical reduction of articular segment

• Absolute stability

Articular surface to diaphysis • Relative stability

Surgical Approaches Parapatellar joint

exposure – 33-C2 or C3

Krettek et al. Injury 1997

Role of Locking Plates Short articular segment

Loss of medial support

– Comminution – Bone loss

Osteoporotic bone

Periprosthetic

70y/o s/p MVC

Classification?

33C2

Approach

Direct Articular Reduction and Fixation

Articular Surface to Shaft

Plate Application

New problem?

28

Overheard at many “expert” discussions

“Our current plates are too stiff!”

Their conclusion and purpose?

Up to 32% healing problems in distal femur fractures treated with locking plates

Callus asymmetry is a clue

We have a problem here!

Titanium versus stainless for distal femur

109 fractures Nonunion rate titanium 7% Nonunion rate stainless 23%

Gaines, OTA 2008

Theory of flexible locking fixation

Ideal stiffness

Basic science suggests ideal stiffness range Locked constructs far exceed ideal range Stiffness reduction + maintenance of

stability

Near cortical slotting

Far cortical locking

Bicortical Technology

Dynamic Locking Screw

New toys

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Retrograde nail may have limited fixation in small segment.

Some total knees may not be able to accommodate a retrograde nail.

Pre-determined Screw trajectory may not capture

enough bone

Flange and posts also

block passage of

screws

14 Weeks Post Op

18 wks Post op

Failure through osteotomy

Postop Plating

6 month f/u healed

Postop

2 mo F/U

6 month weight bearing

pain free

Postop

3 mo f/u

Interlocks with angular stability

Locking interlocks

Extending nail indications Proximal and distal Threaded interface

– Not true locking Threading cortex and nail interference

Metaphyseal clamshell