Open Reduction and Internal Fixation of Distal Femoral Fractures in Adults

Open reduction and internal fixation (ORIF) is a commonly used treatment for fractures throughout the body, including the distal femur.[1] Supracondylar fractures of the femur account for approximately 7% of all femur fractures. They occur just proximal to the knee joint, in the terminal 9 cm of the femur between the metaphyseal-diaphyseal junction and the femoral condyles.[2]

Supracondylar femur fractures have a bimodal distribution within the population. They present in younger patients as a result of high-energy injuries (eg, from motor vehicle collisions or falls from height). In elderly patients, these fractures are often due to low-energy injury mechanisms (eg, simple falls) because of underlying osteoporosis. Supracondylar femur fractures may propagate proximally into the diaphysis or extend distally in the knee joint. Regardless of injury mechanism, supracondylar femur fractures often require surgical treatment for the restoration of limb alignment and fracture stability.[3]

Historically, supracondylar femur fractures were treated with skeletal traction. However, results were poor and complications such as angular deformity, knee stiffness, and delayed mobilization persisted after nonoperative treatment. With advancement in orthopedic implant technology, current consensus among orthopedic surgeons is to treat supracondylar femur fractures surgically.

Indications for ORIF include the following:

• Open fractures
• Fractures associated with neurovascular compromise
• All displaced fractures
• Ipsilateral lower-extremity fractures
• Irreducible fractures
• Pathologic fractures

Patients who are hemodynamically unstable and polytrauma patients may benefit from provisional stabilization of the fracture instead of ORIF. Infections or medical conditions that could pose a life-threatening surgical or anesthetic risk are also contraindications.

There are a few contraindications for a dynamic condylar screw. The condylar screw system is contraindicated when there is a low transcondylar fracture, a coronal fracture, or significant intraarticular comminution.

The bridge plating technique is not appropriate if the soft tissue envelope is not intact (as in severe open fractures), if marked osteoporosis is present, or if there is significant medial bone loss. Under such circumstances, supplemental fixation of the metaphyseal segment is necessary, and a bone graft should be applied to the medial defect.

Best practices

In preparing for surgical treatment of a supracondylar femur fracture, it is essential to have the necessary tools and equipment in place. It is also essential to have a preoperative template in hand as to what the step-by-step approach to the case will be.

Procedural planning

The Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) classification designates the supracondylar femoral fracture as type A.[2]  Type A is further divided into subtypes: subtype A1 is a simple fracture, subtype A2 is a metaphyseal wedge fracture, and subtype A3 is a comminuted metaphyseal fracture.

Options for the surgical treatment of supracondylar femoral fractures include plates, intramedullary nails, external fixators, and total knee arthroplasty. The technique used is determined by fracture pattern, bone quality, the hemodynamic stability of the patient, and the skill and experience of the surgeon.

The 95º angled blade plate is a one-piece, fixed-angle device with a blade distally that is inserted into the femoral condyles. The use of blade plates has been falling out of favor, but it is still an essential skill to have as an orthopedic surgeon.

Condylar screw systems are technically easier to use than the angled blade plate. Sagittal plane adjustments can be made in the plate position, which is not possible with the blade plate. Also, the condylar screw provides interfragmentary compression for fractures with an intercondylar split.

The condylar buttress plate is a broad plate with a cloverleaf distal portion that is contoured to fit the lateral aspect of the distal femur. It may be used for the fixation of minimally displaced fractures, but is most useful in fractures with articular extension in the sagittal and coronal planes. It can also be used as an intraoperative backup device when difficulties are encountered with the angled blade plate or condylar screw system.

The less invasive stabilization system (LISS) from the AO Foundation uses a locking plate and screw construct, which preserves the periosteal blood supply to the fracture. It is used in a similar technique as the buttress plate. The LISS plate is more often used in cases of osteoporotic bone.[4]

Darrith et al compared the outcomes of 50 displaced periprosthetic distal femur fractures treated with ORIF with those of 22 treated with distal femoral replacement (DFR) using multivariate regression analysis. The Knee Society Functional Scores were higher in the ORIF group, but the total incidence of revision was also higher. Additionally, more patients in the ORIF group required repeat revisions.[5]

Ruder et al reported no difference in mortality, complications, discharge disposition, or ambulatory status and living situation at 1 year between ORIF-treated and DFR-treated periprosthetic distal femur fractures.[6]

Necessary equipment depends on technique and includes the following:

• 95º blade plate
• 95º condylar screw
• Distal femur buttress plate
• External fixator

Anesthesia

General anesthesia is used for complete muscle relaxation to facilitate anatomic fracture reduction.

Positioning

The patient is positioned supine on a flat-top Jackson table to allow C-arm imaging. An ipsilateral bump is placed underneath the hip to allow some internal rotation to gain lateral exposure to the distal femur.

Postoperative immobilization depends on the rigidity of your construct and fracture stability. If the fracture is rigidly fixed, a hinged knee brace may be used postoperatively to allow knee range of motion (ROM) and no weightbearing on the extremity until bone healing is evident at approximately 12 weeks.[7]

If the fixation construct is not rigid, the patient may be immobilized in a splint for approximately 4-6 weeks and then transitioned to a hinged knee brace.

Radiographs at regular intervals are necessary to assess fracture healing. Patients may be seen initially at 2 weeks postoperatively and then at monthly intervals until the fracture is healed.

When open reduction with internal fixation (ORIF) is accomplished with plating techniques, a lateral incision that ends distally between the distal pole of the patella and the tibial tubercle is most commonly used.[8]  The vastus lateralis is reflected anteriorly from the lateral intermuscular septum, and the articular surface is visualized by incision of the lateral joint capsule.[9, 10]

The anterolateral approach also provides good exposure of the distal femur. This approach employs the interval between the vastus lateralis and the rectus femoris. It can be extended distally into a lateral parapatellar arthrotomy for access to the knee joint. The medial approach is used for combined lateral and medial plating of very comminuted fractures.

An anteromedial incision begins at the pes anserinus and extends proximally following the adductor canal. The vastus medialis is elevated from the intermuscular septum. As dissection remains anterior to the adductor canal, the superficial femoral artery is not encountered.

The use of blade plates has been falling out of favor, but it is still an essential skill to have as an orthopedic surgeon.

In this technique, a guide wire is placed parallel to the patellofemoral joint and to the femoral condyles as a guide for blade positioning. It is critical for this guide wire to be precisely placed in the coronal, sagittal, and axial planes for accurate alignment. This is typically done with imaging guidance. Intraoperative fluoroscopy is helpful in determining guide-wire position and monitoring the insertion of the seating chisel and the blade plate.

Before insertion of the chisel, three parallel holes are drilled with use of a triple drill guide and a 4.5-mm drill. The holes are expanded with a reamer to create a cortical window for the chisel. With imaging guidance, the plate is inserted onto the condyles. After blade insertion, the femoral shaft is reduced to the plate to restore the anatomic axis of the femur and fixed with 4.5-mm cortical screws. If no bone defects exist, the fracture is compressed with use of the articulated tensioning device.

Blade plate insertion does not necessitate removal of a large amount of bone. Therefore, very distal supracondylar fractures that extend to within 2 cm of the joint surface can be fixed with this device.

Aggressive active knee range of motion (ROM) should begin after surgery. Toe-touch weightbearing should be maintained until the fracture has healed.

The technique for use of the condylar screw system is similar to that for the angled blade plate. A guide wire is placed 2 cm proximal to the joint line, oriented parallel to the condyles and the patellofemoral joint. The wire must be accurately positioned in the coronal and axial planes.

After reaming over the guide wire, the lag screw is inserted and the plate is then applied to the lateral aspect of the distal femur.

Although condylar screw systems are suitable for most supracondylar fractures, there are exceptions. Because of the large size of the lag screw, a minimum of 4 cm of intact bone is required in the distal fragment. A 6.5-mm cancellous screw must also be inserted into the distal fragment to gain rotational stability.

There are a few contraindications for a dynamic condylar screw. The condylar screw system is contraindicated when there is a low transcondylar fracture, a coronal fracture, or significant intraarticular comminution.

Patients should maintain touchdown weightbearing after surgery and active knee ROM until the fracture has healed.

For the distal femur buttress plate technique, a lateral approach to the distal femur is used. The vastus lateralis is split to expose the lateral aspect of the femur. Fracture reduction is achieved with fluoroscopic guidance.

The buttress place is fixed to the femur with 4.5-mm screws. The stability of a fracture fixed with a condylar buttress plate should be assessed intraoperatively by inspecting the interface of the bone and the screw-plate junction for motion during flexion and extension of the knee and during varus and valgus stress of the femur.

If residual instability is present, further fixation with screws or application of a medial plate through a separate medial incision should be considered.

Touchdown weightbearing and active knee ROM are necessary, as in other treatment protocols, until the fracture is healed.

Intramedullary nail fixation of distal femur fractures is possible but difficult. This method of fixation for supracondylar femur fractures is appropriate for polytrauma patients or elderly patients with poor reserve who may not tolerate an extensive open dissection.

Intramedullary nail fixation uses a load-sharing device and does not require the extensive dissection needed for plate fixation of distal femur fractures. It spares the soft tissue surrounding the fracture hematoma to enhance bone healing. Intramedullary nail fixation may be antegrade or retrograde, and specific conditions are required for the use of each method.[7]

Antegrade approach

Antegrade interlocked intramedullary nails have been used successfully in the treatment of extra-articular distal femoral fractures when there is at least 7-10 cm of intact bone in the distal femur or when a 7-cm fragment could be reconstructed with accessory lag screws or distal locking screws. Sufficient bone is required in the distal femur for distal locking screw purchase. The antegrade locked nail is particularly useful in the treatment of supracondylar fractures with proximal extension into the femoral diaphysis.

For this approach, the patient is placed in a supine position on a radiolucent table or a fracture table. It is not favorable to place the patient in a lateral position, because of the increased propensity for angulation at the fracture sit due to the weight of leg itself. There are different entry portals for intramedullary nails. The piriformis fossa or a trochanteric entry nail may be used, depending on surgeon preference. The distal fragment must be controlled with traction or Steinmann pins to facilitate anatomic reduction.

A guide wire is then placed down the femur under fluoroscopic guidance into the distal segment. The guide wire must enter the distal fragment in a central position to properly align the condyles with the shaft. The end point of the guide wire should be between the inferior pole of the patella proximally and the physeal scar distally. Contraindications to antegrade nailing are a preexisting proximal prosthesis or hardware, femoral deformity, obliteration of the intramedullary canal, and insufficient distal bone stock.

Retrograde approach

The position of the patient is supine on a radiolucent fracture table, as with antegrade nailing. The knee is flexed to 45º and can be supported by a leg roll or radiolucent triangle. This technique is done with imaging guidance.

A midline longitudinal skin incision is made, and a medial parapatellar arthrotomy is performed. The patella is then reflected to expose the nail-entry site in the intercondylar notch, just anterior to the femoral attachment of the posterior cruciate ligament. Landmarks for proper placement of the guide wire are in the intercondylar notch on an anteroposterior radiograph and anterior to the Blumensaat line on a lateral radiograph.

Once the fracture is reduced, a guide wire is then passed through the distal femur. To ensure correct alignment of the condyles with the shaft, the entry point and subsequent reaming should be aligned with reference only to the condyles. After reaming to the desired size, the nail is inserted over a guide wire until the distal end lies flush with the cortex of the intercondylar notch. Through a nail-mounted guide, the distal locking screws are placed first, followed by the proximal screws.

A retrograde nail is appropriate for fixation of fractures proximal to total knee arthroplasties and fractures distal to proximal femoral implants.[11]

Potential complications of use of the retrograde supracondylar nail include knee sepsis, stiffness, and patellofemoral pain. The stability of fracture fixation is less than that obtained with the blade plate, and residual instability may necessitate caution in initiating postoperative active knee motion.

Bridge plating is an indirect reduction technique that is appropriate for fractures with a long comminuted metaphyseal segment, an intact soft-tissue envelope, and an extra-articular fracture.

The patient should be placed supine on a radiolucent table with a bump under the ipsilateral hip. Through a lateral approach, the vastus lateralis is elevated from the linea aspera to expose the lateral and anterior aspects of the distal femur. No retractors are placed on the medial supracondylar femur, so as to avoid injury to the superficial femoral artery.

The goal with a bridge plate is to span the fracture fragments to maintain the soft-tissue envelope. The choice of implant is determined by the surgeon, and the plate is applied to the distal femur. Indirect reduction of the metaphyseal segment is performed by applying distraction, either manually or with a femoral distractor. Length and rotation are determined by direct visualization or by fluoroscopy. The plate is then fixed to the femoral shaft above the level of any medial fracture fragments.

No attempt is made to anatomically reduce or fix the comminuted metaphyseal segment. It is imperative that the soft-tissue envelope surrounding the metaphyseal segment not be disturbed so that the vascular supply to the fracture fragments can be preserved. Retractors or bone clamps must not be placed in this region.

The bridge plating technique is not appropriate if the soft-tissue envelope is not intact (as in severe open fractures), if marked osteoporosis is present, or if there is significant medial bone loss. Under such circumstances, supplemental fixation of the metaphyseal segment is necessary, and a bone graft should be applied to the medial defect.

Touchdown weightbearing and active knee ROM are appropriate until the fracture has healed.

External fixation is most frequently considered to be a provisional method of fixation for fractures with extensive soft-tissue damage, such as open fractures, fractures in the unstable polytrauma patient, and fractures with a popliteal artery injury.

The goal of external fixation is to provisionally stabilize the extremity and maintain appropriate length alignment and rotation of the extremity. The external fixator should bridge the fracture site. The pins should be placed in the proximal femur and the middle to distal tibia at sites that avoid the surgical field for future reconstructive procedures. If stability of the distal fragment is questionable, extension of the fixator across the knee may be necessary for a period of 4-6 weeks, after which the tibial extension is removed and active knee motion is started.

Once the patient is stable hemodynamically, the external fixator may be replaced with definitive fixation with a plate or nail, usually in 2 weeks. There also times when the patient’s condition has not changed and external fixation maybe the definitive treatment.

Complications related to the external fixators include pin-tract and joint-space infection, intra-articular pin placement, joint contractures, arthrofibrosis and malunion. The indications for use of small -wire or hybrid fixators for definitive fixation of supracondylar fractures are still evolving. Frames should be large enough to allow for swelling and edema. Extended immobilization may result in limited knee motion.

The thin-wire or hybrid fixator offers a treatment option in situations in which no other device is mechanically suitable. However, most supracondylar femoral fractures are well managed with internal fixation devices.

Supracondylar femoral fractures in elderly persons with very severe osteopenia or preexisting arthrosis pose difficult problems. Fixation with plates may lead to a period of touchdown weightbearing or no weightbearing that is debilitating to an elderly patient to perform activities of daily living.

When the patient has an arthritic knee, however, persistent pain and stiffness are likely despite successful fracture fixation. One treatment option for some of these patients is distal femoral replacement arthroplasty or total knee arthroplasty. This addresses both the fracture and the arthritis and provides the most rapid return of function with immediate weightbearing after surgery. However, significant bone loss takes place during any arthroplasty procedure. These procedures must be tailored to the elderly population with low demands.

Malunion, nonunion, loss of reduction of fracture, infection, wound complications in patients with diabetes, and deep vein thrombosis are all complications of supracondylar femur fractures.[12]  A 2016 study compared distal femoral fractures treated by means of ORIF with those treated by means of minimally invasive plate osteosynthesis (MIPO).[11] The researchers concluded that ORIF resulted in more implant failure and nonunion but less rotational malaignment.

Exact placement of hardware to reduce fracture coupled with rigid internal fixation should lead to union of the fracture site.

Thromboembolic complications may arise after lower-extremity fracture surgery. Therefore, appropriate venous thromboembolism prophylaxis should be administered.

Complications related to the external fixators include pin-tract and joint-space infection, intra-articular pin placement, joint contractures, arthrofibrosis, and malunion. Frames should be large enough to allow for swelling and edema. Extended immobilization may result in limited knee motion.

An incidence of 4% has been reported for surgical site infections (SSIs).[13]  Staphylococcus aureus was the causative agent in over 40% of cases. Risk factors for SSIs included obesity, smoking and diabetes mellitus.