Updated: 10/25/2022

Distal Femur Fractures

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  • Summary
    • Distal femur fractures are traumatic injuries involving the region extending from the distal metaphyseal-diaphyseal junction to the articular surface of the femoral condyles.
    • Diagnosis is made radiographically with CT studies often required to assess for intra-articular extension.
    • Treatment is generally operative with ORIF, intramedullary nail, or distal femur replacement depending on available bone stock, age of patient, and patient activity demands.
  • Epidemiology
    • Incidence
      • Common
        • 3-6% of femur fractures
          • <1% of all fractures
    • Demographics
      • bimodal distribution
        • young healthy males
        • elderly osteopenic females
  • Pathophysiology
    • Mechanism
      • young patients
        • high energy with significant displacement
      • older patients
        • low energy, often fall from standing, in osteoporotic bone, usually with lesser degree of displacement
  • Anatomy
    • Osteology
      • anatomical axis of the distal femur is 6-11 degrees of valgus
        • medial condyle extends more distal than lateral
      • distal femur becomes trapezoidal in cross-section towards the knee
        • lateral cortex of femur slopes ~10 degrees, medial cortex slopes ~25 degrees in the axial plane
      • posterior halves of both condyles are posterior to the posterior cortex of femoral shaft
    • Muscles
      • key deforming forces
        • quadriceps
        • hamstrings
        • adductor magnus
        • gastrocnemius
    • Ligaments
      • anterior cruciate ligament (ACL)
      • posterior cruciate ligament (PCL)
      • medial collateral ligament (MCL)
      • lateral collateral ligament (LCL)
    • Biomechanics
      • hamstring and quadriceps
        • cause the femur to shorten
      • adductor magnus
        • leads to distal femoral varus or valgus
          • direction of deformity is dependent on the location of comminution and the relation of fracture lines to the adductor tubercle
      • gastrocnemius
        • extension at the fracture site (apex posterior)
        • rotation of condyles when an intercondylar split is present
  • Classification
    • Descriptive
      • supracondylar
      • intercondylar
    • OTA: 33
      • A: extraarticular
      • B: partial articular
        • portion of the articular surface remains in continuity with shaft
        • 33B3 is in the coronal plane (Hoffa fragment)
      • C: complete articular
        • articular fragment separated from the shaft
  • Presentation
    • History
      • patients commonly present after fall or traumatic event
    • Symptoms
      • common symptoms
        • pain of distal femur that is made worse with knee movement
        • inability to weight-bear
    • Physical exam
      • inspection
        • tenderness, swelling, ecchymosis of the distal thigh and knee
        • varus or valgus deformity
        • knee effusion may be present with intraarticular involvement
        • evaluate for wounds concerning for an open fracture
          • 5-10% of supracondylar fractures
      • neurovascular exam
        • vascular evaluation
          • potential for injury to popliteal artery if significant displacement
          • Ankle-brachial index (ABI) should be performed if there is a concern for vascular injury
            • angiography is indicated if <0.9
            • >0.9 = 99% negative predictive value
            • <0.9 = 97% specific and 95% sensitive for major arterial injury
  • Imaging
    • Radiographs
      • recommended views
        • AP
        • lateral
      • additional views
        • traction views
          • AP, lateral, and oblique traction views can help characterize injury but are painful for the patient
        • adjacent joints
          • obtain imaging of entire femur to rule out associated injuries
        • contralateral femur
          • consider views of the contralateral femur for pre-operative planning and templating
      • findings
        • can be difficult to visualize intraarticular extension
        • condyles are malrotated in sagittal plane with respects to each other
        • sagittal intra-articular splut is most common
        • Hoffa fracture
          • intra-articular distal femoral fracture in the coronal plane
          • 38% incidence
          • seen on the lateral view
          • missed in up to 31% of cases
          • lateral condyle fractures
            • 80% incidence
        • in elderly patients, evaluate for any pre-existing knee DJD
    • CT scan
      • indications
        • preoperative planning
        • evaluating intra-articular involvement
        • after external fixation to assess pattern, comminution, and intraarticular extension
      • findings
        • separate osteochondral fragments in the area of the intercondylar notch
        • coronal plane fracture (Hoffa fracture) in 40%
        • lateral femoral condyle fractures in 80%
    • Angiography
      • indications
        • ankle-brachial index (ABI) <0.9
        • obvious signs of vascular injury
          • i.e., hard and soft signs (pulselessness, rapidly expanding hematoma, massive bleeding, etc.)
      • findings
        • identifies vascular segments with diminished flow
        • vascular injury
          • displaced distal femur fractures may result in injury to the popliteal artery
  • Treatment
    • Nonoperative
      • hinged knee brace
        • indications (rare)
          • stable, nondisplaced fractures
          • nonambulatory patient
          • patient with significant comorbidities presenting an unacceptably high degree of surgical/anesthetic risk
        • outcomes
          • variable and dependent on multiple factors including patient characteristics and fracture pattern
    • Operative
      • external fixation
        • indications
          • temporizing measure to restore length, alignment, and stability
            • unstable, polytrauma
            • soft tissues not amenable to surgical incisions and internal fixation, or until the patient is stable
            • contamination requiring multiple debridements
          • definitive treatment
            • severe open and/or comminuted fractures
            • patients unstable for surgery
        • outcomes
          • variable and dependent on multiple factors including patient characteristics, fracture pattern, and degree of soft tissue injury
          • 92-100% union rates reported at an average of 4-6 months when used as definitive treatment
      • open reduction internal fixation (ORIF)
        • indications
          • displaced fracture
          • intra-articular fracture
            • traditional 95 degree devices contraindicated in Hoffa fractures
          • periprosthetic fracture with osteoporotic bone
          • nonunion
          • fixed-angle plates required for metaphyseal comminution
            • non-fixed angle plates are prone to varus collapse
        • outcomes
          • variable and dependent on multiple factors including patient characteristics and fracture pattern
          • dual plating (lateral + medial plate) offers greatest degree of axial and torsional stiffness
          • nonunion rates up to 18%
      • retrograde intramedullary nail
        • indications
          • extraarticular fractures
          • simple intraarticular fractures
          • periprosthetic fractures with implants with an "open-box" design
            • distal femoral replacements do not allow retrograde nail fixation
          • traditionally, 4 cm of intact distal femur needed but newer implants with very distal interlocking options may decrease this number
            • independent screw stabilization of intraarticular components placed around nail
        • outcomes
          • variable and dependent on multiple factors including patient characteristics and fracture pattern
          • high union rates reported, more symmetric callus formation compared to plates
          • reduced rates of malunion and higher patient satisfaction compared to ORIF has been reported
      • arthroplasty and distal femoral replacement
        • indications
          • arthroplasty
            • preexisting osteoarthritis with amenable fracture pattern
          • distal femoral replacement
            • low demand patients
              • un-reconstructable fracture
              • fracture around prior total knee arthroplasty with loose component
              • osteoarthritis
        • outcomes
          • variable and dependent on multiple factors including patient characteristics and fracture pattern
          • may have improved ambulatory status and decreased nonunion compared to other methods of fixation
          • reduced longevity compared with internal fixation
          • allows immediate weight bearing
  • Techniques
    • Hinged knee brace
      • technique
        • full time bracing for 6-8 weeks
        • closed-chain ROM exercises at 3-4 weeks
        • restricted weight-bearing until evidence of fracture union
        • serial radiographs to assess for displacement
      • complications
        • wounds from immobilization and bracing
        • knee stiffness
    • External Fixation
      • technique
        • avoid pin placement in the area of planned plate placement, if possible
      • complications
        • pin tract infections
    • Open Reduction Internal Fixation (ORIF)
      • approach
        • lateral
          • suitable for all fracture types
          • arthrotomy for direct reduction of articular components
        • minimally invasive lateral modified anterior (swashbuckler)
          • best when used for extraarticular fractures
          • distal incision large enough to insert plate sub-muscularly
          • screws placed through smaller proximal incisions
          • midline anterior incision that angles slightly lateral
          • lateral parapatellar arthrotomy
          • facilitates articular and lateral distal femur exposure
        • lateral parapatellar
          • fractures with complex articular extension
          • extend incision into quadriceps tendon to evert patella
          • can be used for Hoffa fracture
        • medial parapatellar
          • used for complex medial femoral condyle fractures
        • medial
          • most often used for type B2 and B3 patterns
          • can be used to augment fixation with medial plate in type C3 patterns
        • medial/lateral posterior
          • used for very posterior Hoffa fragment fixation
          • patient placed in the prone position
          • midline incision over the popliteal fossa
          • develop a plane between medial and lateral gastrocnemius
          • capsulotomy to visualize fracture
      • technique
        • goals
          • anatomic joint reduction with rigid fixation
            • restore articular surface before fixation of extraarticular component
          • stable fixation of articular component to diaphysis for early ROM
          • preservation of vascularity
        • direct visualization of the joint allows perfect reduction of intraarticular fractures with lag screw fixation before attaching the articular block to the proximal fragment
          • Hoffa fragments can be captured with an anterior to posterior screw
        • locking plates
          • allows better control of coronal plate compared to 95º angled blate plate and dynamic condylar screw
          • multi-plane screw trajectory allows fixation of coronal (Hoffa) fragments
          • lag screws with locked screws (hybrid construct)
            • intercondylar fractures (usually in conjunction with locked plate)
            • coronal plane fractures
          • locking screw constructs don't rely on bone-plate contact for stability
            • helpful when pre-contoured plates do not precisely match patient anatomy
          • potential to create too stiff of construct leading to nonunion or plate failure
          • NOT an appropriate construct for isolated medial femoral condyle fractures
        • non-fixed angle plate
          • risk of varus malalignment
            • high risk with metaphyseal comminution
        • blade plate fixation
          • requires precise initial implantation of the blade into the distal fragment
          • contraindicated in type C3 fractures
          • may provide poor fixation osteoporotic bone
        • dynamic condylar screw
          • precise sagittal plane alignment is not necessary as plate rotates around the barrel
          • large amount of bone removed, may provide poor fixation in osteoporotic bone
      • complications
        • nonunion
        • knee stiffness
    • Retrograde intramedullary nail
      • approach
        • transtendon approach
          • mid substance longitudinal patellar tendon split
        • medial parapatellar
          • no articular extension
            • 2.5 cm incision parallel to medial aspect of patellar tendon
            • no attempt to visualize articular surface
          • articular extension present
            • continue approach 2-8 cm cephalad
            • incise extensor mechanism 10 mm medial to the patella
            • eversion of patella not typically necessary
            • need to stabilize articular segments before nail placement
      • technique
        • insertion requires ≥70º knee flexion
        • articular reduction and fixation before nail placement
          • lag screws placed out of the intended IMN path
        • starting point at the superior margin of Blumensaat line (lateral) and center of intercondylar notch (AP)
        • blocking screws facilitate reduction and strengthen the construct
        • short nails are rarely indicated
          • implant should reach lesser trochanter to reduce risk of vascular injury
      • complications
        • postoperative knee pain
        • IMN for periprosthetic fractures may result in recurvatum deformity
          • box design requires a posterior starting point
    • Arthroplasty and distal femoral replacement
      • approach
        • extensile anterior, lateral, or medial
          • use previous scar if possible
      • technique
        • resect fracture to allow full weight-bearing
      • complications
        • mechanical failure
          • endoprosthetic metal or polyethylene component fracture
          • aseptic loosening
          • modular component disassociation
          • polyethylene wear synovitis
  • Complications
    • Knee pain/stiffness
      • treatment
        • early ROM
        • physical therapy
    • Symptomatic hardware
      • risk factors
        • lateral plate
          • pain with knee flexion/extension due to IT band contact with the plate
        • medial screw placement
          • excessively long screws can irritate medial soft tissues
          • determine appropriate intercondylar screw length by obtaining an AP radiograph of the knee with the leg internally rotated 30 degrees
      • treatment
        • hardware removal
    • Malunions
      • risk factors
        • common deformities after plating include rotation, hyperextension (recurvatum), and coronal malalignment
          • "golf-club" deformity arises from medial translation of the articular block when the plate is placed too posterior distally
        • percutaneous submuscular fixation with pre-contoured locking plate
          • often rotational malalignment
        • malalignment is more common with IM nails
      • treatment
        • revision internal fixation with osteotomy
        • functional results satisfactory if malalignment is within 5 degrees in any plane
    • Nonunions
      • incidence
        • up to 19%, most commonly in metaphyseal area with articular portion healed (comminution, bone loss and open fractures more likely in metaphysis)
      • risk factors
        • associated with soft tissue stripping in metaphyseal region
      • treatment
        • revision ORIF and autograft indicated
        • consider changing fixation technique to improve biomechanics
    • Infection
      • risk factors
        • diabetics with foot ulcers
      • treatment
        • debridement
        • culture-specific antibiotics
        • hardware removal if fracture stability permits
    • Implant failure
      • incidence
        • up to 9%
      • risk factors
        • improper bridge plating techniques
        • short working length construct
        • stainless steel implants may be inferior to titanium
    • Loss of fixation
      • varus collapse (most common)
        • plate fixation associated with toggling of distal non-fixed-angle screws used for comminuted metaphyseal fractures
        • IM nail fixation
      • Proximal (diaphyseal) screw failure
        • associated with short plates and nonlocked diaphyseal fixation
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Questions (14)
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(OBQ19.162) Figure A is the radiograph of a 45-year-old male who presents to the trauma bay following a gunshot wound. On examination, two wounds, one anteriorly and one posteriorly, are identified. You perform an ABI. Which of the following results would heighten your concern for associated vascular injury and cause you to order a CT angiography?

QID: 214064
















L 1 A

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(OBQ13.57) Fixed-angle implants are often used for fixation of distal femur fractures. Three commonly used implants (Implants A, B and C) are shown in Figures A, B and C respectively. Which of the following statements is true reagarding these implants?

QID: 4692

Implant B is better able to control fractures with a small distal segment than Implants A and C.



Implant C is better able to control coronal plane fractures than Implants A and B.



During insertion, Implant C results in removal of a larger amount of bone, compared with Implants A and B.



Implant A demonstrates less subsidence and greater load to failure compared with Implant C.



Implant A demonstrates lower fixation strength in torsional loading compared with Implant C



L 4 B

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(OBQ12.56) During surgical treatment of the most common variation of distal femoral "Hoffa" fractures, which of the following orientations for screw fixation should be used?

QID: 4416

Medial to lateral screw placement across lateral femoral condyle



Anterior to posterior screw placement across medial femoral condyle



Medial to lateral screw placement across medial femoral condle



Anterior to posterior screw placement across lateral femoral condyle



Anterior to posterior screw placement across intercondylar notch



L 3 B

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(OBQ12.33) A 44-year-old male is involved in a motorcycle collision and presents with the radiographs shown in Figure A. A CT scan is obtained which shows intra-articular extension of the fracture, and lateral locked plating with intercondylar lag screw fixation is planned. Which of the following is important intra-operatively to ensure that the intercondylar screws are contained within the bone and are of appropriate length?

QID: 4393

AP fluoroscopic imaging with the leg in 30 degrees of internal rotation



AP fluoroscopic imaging with the leg in 30 degrees of external rotation



AP fluoroscopic imaging with the knee in full extension



Lateral fluoroscopic imaging with the knee in 30 degrees of internal rotation



Lateral fluoroscopic imaging with the knee in 15 degrees of flexion



L 4 B

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(OBQ11.44) A 68-year-old healthy active male presents after falling and sustaining an injury to his right knee. His medical history is significant only for osteoporosis. Radiographs and representative CT scan images are shown in Figures A-D. What is the most appropriate treatment method for this patient's injury?

QID: 3467

Traction and splinting



Lag screw fixation followed by non-locking plate application



Retrograde supracondylar nail fixation



External fixation and percutaneous screw reduction of the fracture



Lag screw fixation followed by locking plate application



L 1 B

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(OBQ10.219) A lateral distal femoral locking plate is not an appropriate implant for which of the following fractures?

QID: 3318

Figure A



Figure B



Figure C



Figure D



Figure E



L 2 C

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(OBQ08.196) Which of the following treatments of an oligotrophic supracondylar femoral nonunion has been shown to have the best outcome?

QID: 582

Retrograde femoral nailing with adjunct BMP-4



Hybrid external fixation with adjunct BMP-4



Usage of a percutaneous locking plate with adjunct BMP-3



Open reduction and plating with autograft



Open reduction and plating with adjunct calcium phosphate



L 1 C

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(OBQ06.70) A 33-year-old man sustains a femur fracture in a motorcycle accident. AP and lateral radiographs are provided in Figure A. Prior to surgery, a CT scan of the knee is ordered for preoperative planning. Which of the following additional findings is most likely to be discovered?

QID: 181

Tibial eminence fracture



Sagittal plane fracture of the medial femoral condyle



Schatzker I tibia plateau fracture



Coronal plane fracture of the lateral femoral condyle



Axial plane fracture through the medial femoral condyle



L 2 C

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(OBQ05.145) Which of the following is the most appropriate clinical scenario to utilize locking plate and screw technology?

QID: 1031

Intra-articular fracture



Oblique ulnar diaphyseal fracture



Osteoporotic periprosthetic distal femur fracture



Transverse tibial diaphyseal fracture



Spiral humeral diaphyseal-metaphyseal fracture



L 2 C

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