High Yield Overview

DISTAL FEMUR FRACTURES - ARTICULAR RECONSTRUCTION

Bimodal Distribution | Hoffa Fractures | Nail vs Plate Debate

6%Of femur fractures

38%Intra-articular (Hoffa)

30%Mortality in elderly

5-10%Need primary arthroplasty

AO/OTA CLASSIFICATION

33-A

PatternExtra-articular (supracondylar)

TreatmentRetrograde nail (gold standard) or plate

33-B

PatternPartial articular (unicondylar/Hoffa)

TreatmentScrew fixation + buttress plate

33-C

PatternComplete articular (bicondylar)

TreatmentLateral locking plate or dual plating

Periprosthetic

PatternAround TKA component

TreatmentDepends on implant stability

Critical Must-Knows

Hoffa fracture (coronal plane) is often missed on X-ray - CT mandatory for all articular fractures
Retrograde nail preferred for extra-articular (A) types - allows immediate weight bearing
Lateral locking plate (LISS/LCP) workhorse for intra-articular (C) types
Dual plating (medial + lateral) needed for comminuted medial column
Distal femoral replacement (megaprosthesis) indicated for elderly independent ambulators with severe comminution

Examiner's Pearls

"
Look for the coronal plane fracture (Hoffa) in 33-B and 33-C types
"
Gastrocnemius causes recurvatum deformity (pulls distal fragment posterior)
"
Adductor magnus causes varus deformity
"
Quadriceps/hamstrings cause shortening

Clinical Imaging

Imaging Gallery

Primary distal femur fracture AP and lateral viewsCredit: Unknown via Open-i (NIH) (CC-BY)

Periprosthetic distal femur fracture with locking plate fixationCredit: Unknown via Open-i (NIH) (CC-BY)

Lateral locking plate ORIF techniqueCredit: Unknown via Open-i (NIH) (CC-BY)

12-panel comprehensive distal femur fracture cases around implantsCredit: Unknown via Open-i (NIH) - PMC4387367 (CC-BY)

Primary distal femur fracture AP and lateral radiographs — Two-panel radiograph series (1a, 1b) showing AP and lateral views of a primary supracondylar/distal femur fracture in native bone. Demonstrates the classic fracture pattern through the metaphyseal-diaphyseal junction with typical displacement and recurvatum deformity caused by gastrocnemius pull.Credit: PMC - CC BY 4.0

Critical Distal Femur Exam Points

The Hoffa Fracture

38% of intra-articular fractures have a coronal plane (Hoffa) component. Often missed on plain X-ray. CT is mandatory. Usually lateral condyle. Requires AP screws to fix.

Deforming Forces

Gastrocnemius flexes distal fragment (Recurvatum). Adductors cause Varus. Quadriceps causes Shortening. Reduction must overcome these forces (flex knee to relax gastroc).

The Elderly Patient

High 1-year mortality (30%). Goal is immediate weight bearing. Fixation failure is common in osteoporosis. Consider Distal Femoral Replacement (DFR) if fixation dubious.

Vascular Injury

Popliteal artery is tethered at hiatus and trifurcation. Displaced fractures (recurvatum) can injure artery. Check pulses and ABI.

Quick Decision Guide

Age/Function	Fracture Type	Treatment	Pearl
Young / Active	Extra-articular (33-A)	Retrograde IM Nail	Allows immediate load bearing, less soft tissue strip
Young / Active	Intra-articular (33-C)	Lateral Locking Plate (LCP)	Anatomic articular reduction is priority
Any Age	Hoffa Fracture (33-B)	AP Screws + Buttress Plate	Must fix coronal component separately
Elderly / Osteoporotic	Comminuted Intra-articular	Distal Femoral Replacement	Immediate WB, avoid non-union/failure
Periprosthetic	Loose Implant	Revision Arthroplasty	Fixation will fail if implant loose

Mnemonic

GRASDeforming Forces

Gastrocnemius

Pulls distal fragment into EXTENSION (recurvatum)

Recurvatum

The resulting deformity

Adductors

Pull shaft into VARUS

Shortening

Quadriceps/Hamstrings cause shortening

Memory Hook:The GRAS pulls the femur into a deformed position!

Mnemonic

HOFFAHoffa Fracture Features

Hidden

Often occult on plain X-ray

One condyle

Usually lateral (more common than medial)

Flexion

Occurs in flexion (posterior element)

Fixation

Requires AP screws (P-to-A or A-to-P)

Articular

Intra-articular coronal shear

Memory Hook:HOFFA fractures are Hidden One-condyle Flexion Articular injuries!

Mnemonic

LALSurgical Goals

Length

Restore length first

Alignment

Restore rotation and axis

Locking

Stable fixation for early motion

Memory Hook:Restore LAL to get the femur back to normal!

Overview and Epidemiology

Why This Topic Matters

Distal femur fractures are challenging due to comminution, osteoporosis, and intra-articular extension. The examiner will test your decision-making between nailing (A-type) vs plating (C-type) vs arthroplasty (elderly), and your ability to spot and manage the Hoffa fragment.

Demographics

Bimodal: Young males (high energy) and Elderly females (low energy)
Osteoporosis is major factor in elderly
Periprosthetic fractures increasing with TKA volume

Impact

High energy: Axial load with varus/valgus
Low energy: Simple fall (spiral pattern)
Dashbord: Axial load in flexion

Anatomy

Anatomical Safe Zones

The distal femur is trapezoidal - wider posteriorly. The lateral surface is inclined 10 degrees (not vertical) - plates must match this or risk malalignment. The Blumensaat's line indicates slope of intercondylar notch.

Distal Femur Anatomy

Shape

Flares from cylinder to condyles
Lateral wall inclined 10 degrees (slopes medial)
Anterior wall inclined 25 degrees (trochlea)
Medial condyle extends more distal (plus distal joint angle)

Muscle Attachments

Gastrocnemius: Posterior condyles (flexes fragment)
Adductor Magnus: Adductor tubercle (varus force)
Quadriceps: Patella (shortening)
Hamstrings: Proximal tibia (shortening)

Classification Systems

AO/OTA Classification (33)

Type	Description	Subtypes	Treatment
33-A	Extra-articular	A1: Simple, A2: Wedge, A3: Comminuted	Retrograde Nail or Plate
33-B	Partial Articular	B1: Lateral (Hoffa), B2: Medial, B3: Anterior	Screw fixation + Buttress
33-C	Complete Articular	C1: Simple/Simple, C2: Simple/Multi, C3: Multi/Multi	Lateral Locking Plate

Type B3 (coronal shear) is the Hoffa. Lateral condyle (Letenneur I-III) most common. Need to fix with countersunk screws from anterior to posterior (or vice versa) perpendicular to fracture line.

Bilateral Hoffa fractures on lateral knee radiographs — Two-panel lateral knee radiographs (A, B) showing bilateral Hoffa fractures. Note the characteristic 'double density' sign in the lateral femoral condyles representing the coronal plane fracture fragment - these are easily missed on AP views and demonstrate why CT is mandatory for all suspected intra-articular distal femur fractures.Credit: PMC - Hoffa fracture case series - CC BY 4.0

Clinical Assessment

Examination

Deformity: Usually shortened and externally rotated
Skin: Check posterolateral (open spikes) and anterior (contusion)
Vascular: Pulses, ABI - high index of suspicion
Nerves: Peroneal/Tibial nerve exam

History

Pre-injury function: Independent vs housebound (guides arthroplasty decision)
TKA History: Implant type, time since surgery
Comorbidities: Optimize for surgery

The Floating Knee

Look for ipsilateral tibial shaft or plateau fracture ("floating knee"). This is a high-energy injury with significantly increased complications (fat embolism, vascular injury, compartment syndrome). Fix femur first usually.

Investigations

Imaging Protocol

ImmediateX-ray Series

AP and Lateral of femur and knee. Traction view can help define phenotype. Full length femur to rule out ipsilateral hip/shaft.

MandatoryCT Scan

Current standard of care for ALL distal femur fractures. 38% have coronal (Hoffa) fractures missed on X-ray. Helps plan articular reduction screw trajectory.

VascularCTA

If pulses asymmetric or ABI less than 0.9. Low threshold due to popliteal tethering.

Traction View

A traction X-ray (manually applied traction) in ED often reveals the fracture pattern better than the initial comminuted mess. Helps determine if the articular block is reconstructable.

CT scan showing Hoffa fracture in axial and sagittal planes — Two-panel CT series demonstrating Hoffa fracture: (A) Axial view clearly showing the coronal plane fracture through the posterior femoral condyle, (B) Sagittal reconstruction confirming the posterior condylar fragment. CT is the gold standard for detecting these often occult injuries and is mandatory for all intra-articular distal femur fractures.Credit: PMC - Clinical outcomes of locked plating - CC BY 4.0

MRI of Hoffa fracture showing coronal plane fracture line — Three-panel MRI series (A, B, C) demonstrating Hoffa fracture of the lateral femoral condyle. White arrows indicate the coronal plane fracture line. Panel A shows coronal view; panels B and C show sagittal views clearly demonstrating the posterior condylar fragment. MRI also evaluates associated ligamentous and meniscal injuries.Credit: PMC - Hoffa Fracture of the Femoral Condyle - CC BY 4.0

Management Algorithm

Elderly Management Paradigm

In elderly patients, the goal is immediate full weight bearing. Fixation that requires restricted weight bearing (NWB) has high mortality and failure rates. If fixation cannot support FWB, choose Distal Femoral Replacement (arthroplasty).

Surgical Approaches

Approach	Indication	Interval	Nerve at Risk
Lateral Parapatellar	Standard for ORIF	Vastus lateralis / Rectus	Superior lateral genicular artery
Swashbuckler	Complex articular	Lat parapatellar + Snip	Superior medial genicular
Medial Subvastus	Medial plate	Vastus medialis / Adductors	Saphenous nerve
Trans-tendinous	Nail entry	Split patellar tendon	Infrapatellar branch saphenous

The Swashbuckler Approach

The Swashbuckler approach is a modified lateral parapatellar approach with a lateral quadriceps snip. It allows the patella to subluxate medially, giving complete exposure of the articular surface while preserving blood supply.

Surgical Technique

Lateral Locked Plating - ORIF

Patient Positioning:

Supine on radiolucent table
Bump under ipsilateral hip for neutral rotation
Knee slightly flexed over radiolucent triangle

Approach:

Lateral approach through iliotibial band
Preserve soft tissue attachments to bone
MIPO technique for extra-articular fractures
Direct exposure for intra-articular fractures

Articular Reduction:

K-wires for provisional fixation
Anatomic articular reduction (step-off under 2mm)
Lag screws (outside plate footprint) for condylar splits
Confirm under fluoroscopy

Plate Application:

Anatomic distal femur locking plate
Submuscular plate insertion for shaft
Confirm alignment before proximal fixation
Avoid varus malreduction (most common error)

Locking Screws:

Locking screws in metaphysis and distal fragment
Mix of locking and cortical proximally
Leave 2-3 empty holes at fracture for flexibility

Anatomic articular reduction and stable fixation are essential for good outcomes.

Four-panel showing lateral locking plate ORIF for distal femur fracture — Four-panel radiograph series demonstrating distal femur fracture treated with lateral anatomic locking plate (LISS/LCP). AP and lateral views show optimal plate positioning along the lateral femoral cortex with multiple locking screws providing fixed-angle stability in the comminuted distal fragment. Note the bridge plating technique with empty holes at the fracture zone to allow micromotion and callus formation.Credit: PMC - CC BY 4.0

Complications

Complication	Rate	Risk Factors	Management
Non-union	5-10%	Bridge plating too stiff, smoking, open	Dual plating + Bone graft
Malunion (Valgus/Varus)	10-20%	Poor intra-op alignment	Osteotomy if symptomatic
Infection	3-5%	Open fracture, OR time, Obesity	Debridement, hardware removal
Knee Stiffness	Common	Prolonged immobilization	Arthroscopic lysis of adhesions
Implant Failure	5%	Early WB on weak fixation	Revision to DFR or nail
Prominent Hardware	10-20%	Iliotibial band irritation	Removal after union

Hardware complication following distal femur fracture fixation — Four-panel radiograph series (a, b, c, d) demonstrating hardware-related complications following distal femur fracture fixation with lateral locking plate. Red arrows indicate areas of concern including prominent hardware and potential screw-related issues. Prominent hardware causing iliotibial band irritation is a common complication requiring removal after fracture union.Credit: PMC - CC BY 4.0

Postoperative Care and Rehabilitation

Rehab Protocol

Early MotionWeek 0-2

Immediate ROM is critical to prevent adhesions. CPM machine often used. Toe-touch weight bearing (unless nail/DFR).

ProgressionWeek 6

X-ray check. Advance weight bearing if callus visible.

Full FunctionMonth 3

Full weight bearing. Quad strengthening. Returns to baseline 6-12 months.

Weight Bearing Status

Nail: WBAT usually allowed. DFR: WBAT allowed. Plate: TDWB/PWB (15kg) for 6-12 weeks until callus. This restriction is why plating is less ideal for frail elderly.

Outcomes and Prognosis

Union and Function

Outcomes by Fixation Method

Method	Union Rate	Time to Union	Key Considerations
Retrograde nail	85-95%	12-16 weeks	Early WB, good for extra-articular
Lateral locking plate	85-90%	16-20 weeks	Protected WB needed, versatile
Dual plating	80-90%	16-24 weeks	For unstable medial column
Distal femoral replacement	N/A	N/A	Salvage or severe comminution in elderly

Prognostic Factors

Favorable Factors

Extra-articular fracture pattern. Good bone quality. Anatomic reduction achieved. Early ROM and rehabilitation. Non-smoker.

Unfavorable Factors

Complex articular involvement (C3). Severe osteoporosis. Varus malreduction. Delayed surgery or infection. Open fracture.

Functional Outcomes

Most patients achieve functional independence and return to baseline mobility. Knee stiffness is the most common functional problem, particularly with prolonged immobilization. Arthrofibrosis may require manipulation or arthroscopic lysis of adhesions. Long-term post-traumatic arthritis is common with intra-articular injuries, with some patients requiring eventual arthroplasty.

Evidence Base and Key Trials

Nail vs Plate RCT

Markmiller M, Konrad G, Südkamp N. • Clin Orthop Relat Res (2004)

Key Findings:

RCT comparing LISS plate vs Retrograde Nail (n=32)
No difference in union rates or infection
Nail group had significantly shorter operating time
No difference in ROM or functional scores

Clinical Implication: Both are acceptable, but Nail is faster and less invasive for extra-articular patterns.

Limitation: Small sample size.

Treatment of Distal Femur Fractures

Smith JR, Halliday R, Kelly MB et al. • Eur J Orthop Surg Traumatol (2016)

Key Findings:

Systematic review of 29 studies (over 2000 fractures)
Locking plates had higher non-union rate (5.3%) compared to nail (1.5%) in extra-articular fractures
Plates had higher infection rate (5.3% vs 3%)
Nailing superior for A-type fractures

Clinical Implication: Reliable evidence supports nailing for extra-articular fractures to reduce complications.

Limitation: Heterogeneous studies included.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

Scenario 1: Low Energy Fall

EXAMINER

"A 78-year-old female presents after a fall on stairs. Knee is swollen and painful. X-ray shows distal femur fracture (33-A2)."

EXCEPTIONAL ANSWER

This is a low-energy supracondylar femur fracture in an osteoporotic patient. I would perform a full primary survey (ATLS) to rule out other injuries, though likely isolated. My goal is early mobilization to prevent medical complications. I would obtain a CT to check for occult intra-articular extension (Hoffa). If it is truly extra-articular (A2), my gold standard treatment is a **Retrograde Intramedullary Nail** as it shares load and allows immediate weight bearing. If she had a pre-existing TKA with a closed box, the nail is blocked, so I would use a lateral locking plate. If she has severe arthritis and comminution, I would consider a DFR.

KEY POINTS TO SCORE

Identify osteoporotic nature

Rule out Hoffa (CT)

Prefer nail for A-type (load sharing)

Consider DFR if severe arthritis/comminution

COMMON TRAPS

✗Missing ipsilateral hip fracture

✗Choosing a plate (NWB) for a frail elderly patient

✗Ignoring TKA status (implant type)

LIKELY FOLLOW-UPS

"What if the nail entry point is blocked by a TKA?"

"How do you manage if you intra-operatively fracture the femoral shaft?"

VIVA SCENARIOChallenging

Scenario 2: The Hoffa Fracture

EXAMINER

"A 30-year-old motorcyclist has a C3 distal femur fracture. CT shows a displaced coronal plane (Hoffa) fracture of the lateral condyle."

EXCEPTIONAL ANSWER

This is a high-energy bi-condylar fracture with a Hoffa component. It is a surgical urgency. My priority is anatomic articular reduction. I would position supine with a bump. I would likely use a **Lateral Parapatellar Approach** for direct visualization of the joint. I must reduce and fix the Hoffa fragment first, typically with two 3.5mm cortical or cancellous screws inserted Anterior-to-Posterior (countersunk so they don't block the plate). Once the articular block is reconstructed, I would attach it to the shaft with a lateral locking plate using bridge plating technique for the metaphysis.

KEY POINTS TO SCORE

Hoffa needs direct visualization

Fix Hoffa first (AP screws)

Countersink screws to avoid plate conflict

Anatomic articular reduction is key

COMMON TRAPS

✗Trying to reduce Hoffa with the plate alone

✗Missing the Hoffa fragment on initial X-ray

✗Using screws that are too long (joint penetration)

LIKELY FOLLOW-UPS

"Which approach gives best view of lateral Hoffa?"

"What is the Swashbuckler approach?"

VIVA SCENARIOCritical

Scenario 3: Non-Union

EXAMINER

"45-year-old male, 6 months post-LISS plating of open distal femur fracture. Pain on WB. X-ray shows broken plate."

EXCEPTIONAL ANSWER

This is an infected non-union until proven otherwise. I would work him up with ESR/CRP and consider aspiration. If infection is ruled out, this is a mechanical failure (aseptic non-union). The likely cause is instability (working length too long or too short) or varus collapse. My management would be 2-stage if infected. If aseptic: Removal of broken hardware, fracture site preparation (decortication), correction of varus deformity, and re-fixation. I would use **Dual Plating** (adding a medial plate via subvastus approach) and substantial iliac crest bone graft to address the biology and stability.

KEY POINTS TO SCORE

Rule out infection first (ESR/CRP/Aspiration)

Identify mechanical cause (varus, stiffness)

Dual plating for rescue (medial strut)

Bone graft for biology

COMMON TRAPS

✗Re-plating laterally without addressing medial column (fail again)

✗Ignoring potential infection

✗Not correcting varus

LIKELY FOLLOW-UPS

"How does the medial plate prevent failure?"

"When would you use a nail for salvage?"

MCQ Practice Points

Hoffa Fracture Location

Q: Which femoral condyle is most commonly involved in a Hoffa fracture? A: Lateral Condyle - The lateral condyle is involved in 70-85% of cases due to the valgus vector of force in a flexed knee.

Deforming Forces

Q: Which muscle is responsible for the recurvatum (hyperextension) deformity of the distal fragment? A: Gastrocnemius - It originates on the posterior femoral condyles and flexes the distal fragment.

Nail vs Plate

Q: In the 'Fixation Implant Trial' (FIT), what was the main advantage of nailing over plating? A: Initial Quality of Life - Nailing showed better quality of life scores at 6-12 weeks, likely due to earlier weight-bearing and less soft tissue dissection.

Artery at Risk

Q: A medial locking screw placed too long is at risk of injuring which structure? A: Femoral Vessel (at Hunter's canal) - If placed in the proximal part of the plate. Distally, the popliteal vessels are posterior and central.

AO Classification

Q: What defines an AO 33-C3 distal femur fracture? A: Complete articular fracture with multifragmentary articular component - The 33 designates distal femur, C indicates complete articular involvement, and 3 denotes comminution of the articular surface.

Reduction Sequence

Q: In an AO 33-C fracture, what is the correct order of reduction? A: Articular first, then metaphyseal - First reconstruct the articular surface anatomically, then reduce the articular block to the shaft. "Fix the joint to the shaft."

Australian Context

The AOANJRR (Australian Orthopaedic Association National Joint Replacement Registry) reports that Distal Femoral Replacement (DFR) is increasingly used for acute fractures in the elderly.

DFR for fracture has a higher revision rate than DFR for neoplastic disease.
Main reasons for revision: Infection and Aseptic Loosening.
For periprosthetic fractures (around TKA), fixation failure is high if the primary implant is loose.

ACSQHC Guidelines:

Elderly patients (over 65) with femur fractures should be mobilized within 24 hours.
Multidisciplinary Orthogeriatric care reduces mortality.

DISTAL FEMUR FRACTURES

High-Yield Exam Summary

Key Anatomy

•Trapezoidal shape (wider posterior)
•Lateral wall inclined 10 degrees
•Popliteal artery tethered posteriorly
•Gastrocnemius causes Extension (Recurvatum)

Classification

•Type A: Extra-articular → Nail or Plate
•Type B: Partial articular → Screws
•Type C: Complete articular → Plate
•Hoffa: Coronal shear (Lateral > Medial)

Surgical Rules

•Reconstruct articular block first (anatomical)
•Attach block to shaft (functional alignment)
•Bridge plating for length/rotation
•Compression for articular surface

Implants

•Retrograde Nail: Load sharing, Early WB
•Lateral Locking Plate: Fixed angle, Buttress
•Dual Plate: For medial comminution
•DFR: For elderly/salvage

Complications

•Non-union (Medial instability)
•Malunion (Varus/Recurvatum)
•Infection (Open fracture)
•Knee Stiffness

Key Studies

•FIT Trial: Nail better QOL early
•Smith: obesity/smoking risk factors
•Sanders: Dual plating biomechanics
•Markmiller: Nail vs Plate RCT

Age/Function

Fracture Type

Treatment

Pearl

Young / Active

Extra-articular (33-A)

Retrograde IM Nail

Allows immediate load bearing, less soft tissue strip

Young / Active

Intra-articular (33-C)

Lateral Locking Plate (LCP)

Anatomic articular reduction is priority

Any Age

Hoffa Fracture (33-B)

AP Screws + Buttress Plate

Must fix coronal component separately

Elderly / Osteoporotic

Comminuted Intra-articular

Distal Femoral Replacement

Immediate WB, avoid non-union/failure

Periprosthetic

Loose Implant

Revision Arthroplasty

Fixation will fail if implant loose

Type

Description

Subtypes

Treatment

33-A

Extra-articular

A1: Simple, A2: Wedge, A3: Comminuted

Retrograde Nail or Plate

33-B

Partial Articular

B1: Lateral (Hoffa), B2: Medial, B3: Anterior

Screw fixation + Buttress

33-C

Complete Articular

C1: Simple/Simple, C2: Simple/Multi, C3: Multi/Multi

Lateral Locking Plate

Approach

Indication

Interval

Nerve at Risk

Lateral Parapatellar

Standard for ORIF

Vastus lateralis / Rectus

Superior lateral genicular artery

Swashbuckler

Complex articular

Lat parapatellar + Snip

Superior medial genicular

Medial Subvastus

Medial plate

Vastus medialis / Adductors

Saphenous nerve

Trans-tendinous

Nail entry

Split patellar tendon

Infrapatellar branch saphenous

Lateral Locked Plating - ORIF

Patient Positioning:

Supine on radiolucent table
Bump under ipsilateral hip for neutral rotation
Knee slightly flexed over radiolucent triangle

Approach:

Lateral approach through iliotibial band
Preserve soft tissue attachments to bone
MIPO technique for extra-articular fractures
Direct exposure for intra-articular fractures

Articular Reduction:

K-wires for provisional fixation
Anatomic articular reduction (step-off under 2mm)
Lag screws (outside plate footprint) for condylar splits
Confirm under fluoroscopy

Plate Application:

Anatomic distal femur locking plate
Submuscular plate insertion for shaft
Confirm alignment before proximal fixation
Avoid varus malreduction (most common error)

Locking Screws:

Locking screws in metaphysis and distal fragment
Mix of locking and cortical proximally
Leave 2-3 empty holes at fracture for flexibility

Anatomic articular reduction and stable fixation are essential for good outcomes.

Complication

Rate

Risk Factors

Management

Non-union

5-10%

Bridge plating too stiff, smoking, open

Dual plating + Bone graft

Malunion (Valgus/Varus)

10-20%

Poor intra-op alignment

Osteotomy if symptomatic

Infection

3-5%

Open fracture, OR time, Obesity

Debridement, hardware removal

Knee Stiffness

Common

Prolonged immobilization

Arthroscopic lysis of adhesions

Implant Failure

Early WB on weak fixation

Revision to DFR or nail

Prominent Hardware

10-20%

Iliotibial band irritation

Removal after union

Method

Union Rate

Time to Union

Key Considerations

Retrograde nail

85-95%

12-16 weeks

Early WB, good for extra-articular

Lateral locking plate

85-90%

16-20 weeks

Protected WB needed, versatile

Dual plating

80-90%

16-24 weeks

For unstable medial column

Distal femoral replacement

N/A

Salvage or severe comminution in elderly

Vessel	Location	Risk
Popliteal Artery	Posterior to femur	Tethered at hiatus, risk in recurvatum
Superior Geniculars	Wrap around metaphysis	Source of fracture hematoma
Inferior Geniculars	Joint level	Bleeding in arthrotomy

Angle	Normal Value	Relevance
Lateral Distal Femoral Angle (LDFA)	81 degrees (valgus)	Goal of reduction to standard
Joint Line Convergence	0-2 degrees	Knee joint line parallel
Anatomic Axis	5-7 degrees Valgus	Shaft to joint line relationship

Type	Implant Status	Bone Stock	Treatment
Type I	Stable	Good	Locking Plate or Nail
Type II	Stable	Poor/Comminuted	Locking Plate or DFR
Type III	Loose	Any	Revision Arthroplasty (DFR)

Indication	Approach	Benefit
Medial comminution	Medial subvastus	Prevents varus collapse
Low intercondylar fracture	Dual incisions	Captures low fragments
Non-union variants	Judet decortication	Rigid stability

Vessel	Location	Risk
Popliteal Artery	Posterior to femur	Tethered at hiatus, risk in recurvatum
Superior Geniculars	Wrap around metaphysis	Source of fracture hematoma
Inferior Geniculars	Joint level	Bleeding in arthrotomy

Distal Femur Fractures

Distal Femur Fractures

DISTAL FEMUR FRACTURES - ARTICULAR RECONSTRUCTION

AO/OTA CLASSIFICATION

Critical Must-Knows

Examiner's Pearls

Clinical Imaging

Imaging Gallery

Critical Distal Femur Exam Points

The Hoffa Fracture

Deforming Forces

The Elderly Patient

Vascular Injury

Quick Decision Guide

GRASDeforming Forces

HOFFAHoffa Fracture Features

LALSurgical Goals

Overview and Epidemiology

Demographics

Impact

Anatomy

Anatomical Safe Zones

Biomechanical Stability

Mechanical Axis

Implant Mechanics

Distal Femur Anatomy

Shape

Muscle Attachments

Vascular Considerations

Normal Radiographic Parameters

Classification Systems

AO/OTA Classification (33)

Supracondylar/Periprosthetic (Rorabeck/Lewis)

Clinical Assessment

Examination

History

The Floating Knee

Investigations

Imaging Protocol

Management Algorithm

Elderly Management Paradigm

Surgical Approaches

Retrograde Intramedullary Nail

Technique Steps

Pros

Cons

Lateral Locking Plate (LCP/LISS)

Technique Steps

Distal Femoral Replacement (DFR)

Indications

Outcomes

Dual Plating (Medial + Lateral)

Medial Column Collapse

Surgical Technique

Lateral Locked Plating - ORIF

Retrograde Intramedullary Nailing

Avoiding Complications

Complications

Postoperative Care and Rehabilitation

Rehab Protocol

Outcomes and Prognosis

Union and Function

Outcomes by Fixation Method

Prognostic Factors

Favorable Factors

Unfavorable Factors

Functional Outcomes

Evidence Base and Key Trials

Nail vs Plate RCT

Treatment of Distal Femur Fractures

DFR vs Fixation in Elderly

Rationale for Dual Plating

LISS Plate Outcomes

Exam Viva Scenarios

Scenario 1: Low Energy Fall

Scenario 2: The Hoffa Fracture

Scenario 3: Non-Union

MCQ Practice Points

Australian Context

DISTAL FEMUR FRACTURES