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 login to view 1 more bullet 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 login to view 1 more bullet 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 login to view 1 more bullet neurovascular exam vascular evaluation login to view 5 more bullets Imaging Radiographs recommended views AP lateral additional views traction views login to view 1 more bullet adjacent joints login to view 1 more bullet contralateral femur login to view 1 more bullet findings can be difficult to visualize intraarticular extension condyles are malrotated in sagittal plane with respects to each other sagittal intra-articular split is most common Hoffa fracture login to view 6 more bullets 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 login to view 1 more bullet findings identifies vascular segments with diminished flow vascular injury login to view 1 more bullet Treatment Nonoperative immobilization with hinged knee brace indications (rare) login to view 3 more bullets outcomes login to view 1 more bullet Operative closed reduction and external fixation (ExFix) indications login to view 7 more bullets outcomes login to view 2 more bullets open reduction internal fixation (ORIF) indications login to view 7 more bullets outcomes login to view 4 more bullets closed reduction and intramedullary fixation (IMN) indications login to view 6 more bullets outcomes login to view 3 more bullets arthroplasty indications login to view 8 more bullets outcomes login to view 7 more bullets 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 half-pin placement within the anterior femur has a narrow safe zone complications pin tract infections Open Reduction Internal Fixation (ORIF) approach lateral login to view 2 more bullets minimally invasive lateral modified anterior (swashbuckler) login to view 6 more bullets lateral parapatellar login to view 3 more bullets medial parapatellar login to view 1 more bullet medial login to view 2 more bullets medial/lateral posterior login to view 5 more bullets technique goals login to view 4 more bullets direct visualization of the joint allows perfect reduction of intraarticular fractures with lag screw fixation before attaching the articular block to the proximal fragment login to view 1 more bullet locking plates login to view 9 more bullets nail-plate combination login to view 2 more bullets non-fixed angle plate login to view 2 more bullets blade plate fixation login to view 3 more bullets dynamic condylar screw login to view 2 more bullets complications nonunion knee stiffness Retrograde intramedullary nail approach transtendon approach login to view 1 more bullet medial parapatellar login to view 8 more bullets technique insertion requires ≥70º knee flexion articular reduction and fixation before nail placement login to view 1 more bullet 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 login to view 1 more bullet complications postoperative knee pain IMN for periprosthetic fractures may result in recurvatum deformity login to view 1 more bullet Arthroplasty and distal femoral replacement approach extensile anterior, lateral, or medial login to view 1 more bullet technique resect fracture to allow full weight-bearing complications mechanical failure login to view 4 more bullets Complications Knee pain/stiffness treatment early ROM physical therapy Symptomatic hardware risk factors lateral plate login to view 1 more bullet medial screw placement login to view 2 more bullets treatment hardware removal Malunions risk factors common deformities after plating include rotation, hyperextension (recurvatum), and coronal malalignment login to view 1 more bullet percutaneous submuscular fixation with pre-contoured locking plate login to view 1 more bullet 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