Practice Essentials
Supracondylar femur fractures are becoming more common as the population ages. These fractures usually occur in elderly patients with multiple comorbidities and osteoporotic bone; thus, a high rate of complications exists. [1]
The goal in treating supracondylar femur fractures, as in treating any periarticular fracture in a weightbearing bone, is restoration of a stable limb for functional, pain-free ambulation. Initially, fixation and, finally, healing of the bone restores stability. Maintaining anatomic alignment and length and preventing stiffness restore function. Avoiding arthritis, which requires restoration of anatomic congruent joint surfaces and maintaining the normal mechanical axis of the limb, prevents pain.
Supracondylar femur fractures require anatomically stable internal fixation for best results. Historically, traction achieved adequate results for the treatment of these fractures; however, the outcomes probably would not be considered acceptable today. Maintaining leg length and preventing varus malalignment is difficult with traction. Although surgical risks were avoided, the patient was exposed to the risks of prolonged bedrest, including pulmonary complications, deep venous thrombosis, pressure injuries, disuse osteoporosis, and generalized muscle atrophy and deconditioning. [1]
All current authors agree that the best results are now achieved with operative methods. [2] Involvement of the articular surface demands a congruent anatomic reduction to prevent or minimize posttraumatic arthritis and provide bone stock for later knee replacement or fusion. [3, 4]
Severe comminution often requires fixation of multiple independent fragments with one device to minimize soft-tissue damage. [5] Severely comminuted distal femur fractures are especially hard to treat properly. [5, 6, 3, 7, 1, 4, 2, 8, 9] Obtaining adequate fixation may be technically challenging, especially when multiple fragments are present. The significant forces applied to this area, even during restricted patient activities, require a strong implant; however, fixation is difficult because of the wide canal, the thin cortex, and the relatively poor bone quality of the distal femur. [7, 8, 10]
Most surgical failures are caused by inadequate fixation of fracture fragments. [11] Each device has limitations, and no implant can stabilize every fracture type; however, for best results, the device chosen must provide fixation rigid enough for early motion. [5, 4, 12, 13] If comminution and the fracture pattern compromise the use of an implant, the surgeon should be flexible and choose the device that fits best. [14]
Supracondylar femur fractures that occur after total knee replacement are also more difficult to treat adequately because the knee replacement prosthesis can interfere with fixation implants. [15, 16, 17]
Anatomy
The distal femur is funnel-shaped, and the area where the stronger diaphyseal bone meets the thinner and weaker metaphyseal bone is prone to fracture with direct or indirect trauma. The surgeon needs to be aware of the shape of the bone when planning surgery so that the implant matches the bone.
The approach to the thigh is a standard lateral one, with an incision through the fascia lata and access to the bone along the intermuscular septum under the vastus lateralis. The femoral artery is medial; other neurovascular structures are posterior and thus should not be encountered during surgery.
Etiology
Supracondylar femur fractures usually occur as a result of low-energy trauma in osteoporotic bone in elderly persons or high-energy trauma in young patients. Fractures proximal to knee replacements may be caused by notching of the anterior cortex when the surgeon placed the prosthesis or may be secondary to the stress riser effect of the interface between the rigid metal and soft bone. [18, 19] The treating physician must also be aware of the potential for pathologic fractures through metastatic lesions or primary bone tumors in this area.
Prognosis
With stable fixation, anatomic alignment, and restoration of intra-articular congruency, most patients do well. The more comminuted the fracture and the poorer the quality of bone, fixation, or reduction, the worse the prognosis. Severe comminuted type C3 fractures are expected to develop significant stiffness and posttraumatic arthritis. Patients with open fractures fare worse than those with closed fractures.
Periprosthetic fractures and dementia, heart failure, advanced renal disease, and metastasis lead to reduced survival. Dealying surgery for longer than 4 days leads to increases in 6-month and 1-year mortality. Mortality after native fractures of the distal femur in the geriatric population is high and is comparable to mortality after hip fractures. [20]
A case series of 52 distal femur fractures among 49 patients older than 65 years reported that the 3-month and 1-year mortality rates were 29% and 35%, respectively. Only 22% of the patients were able to return home after surgical treatment and in-patient rehabilitation, the remaining 78% required residential or nursing home care. [21]
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Supracondylar femur fracture treated in traction. Traction allows nonoperative restoration of length and alignment while the patient is stabilized for surgery, but it is associated with the major complications of prolonged bedrest when used as definitive treatment.
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Supracondylar femur fracture treated with a dynamic condylar screw plate. This device allows fixed-angle stabilization of the fracture, which usually prevents late loss of reduction, but it is technically limited because it cannot be used to fix multiple fragments.
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Supracondylar femur fracture treated with a blade plate. This device allows fixed-angle stabilization of the fracture, which usually prevents late loss of reduction, but it is technically limited because it cannot be used to fix multiple fragments.
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Supracondylar femur fracture treated with a supracondylar buttress plate. This device provides multiple holes for screw fixation of multiple fragments, but it is not a fixed-angle implant so it may allow late deformity.
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Supracondylar femur fracture treated by retrograde intramedullary nail. Intramedullary devices are mechanically stronger than plates but have limited ability to control multiple fragments and require exposure through the knee joint.
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Supracondylar femur fracture treated with Zickel flexible intramedullary rods. These devices act as an internal splint and can be placed rapidly with minimal blood loss and surgical exposure but do not control length and alignment.
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Supracondylar femur fracture treated with external fixation and minimal internal fixation. This technique allows immediate restoration of length and alignment with minimal surgical exposure, but it often cannot hold the alignment in the long term and has associated problems with pin care.
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Supracondylar femur fracture treated with a cobra plate. This device is strong and can achieve fixation in multiple fragments but is not fixed angle.
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Supracondylar femur fracture treated with a tibial buttress plate. This type of plate is rarely used for these fractures but can allow low-profile fixation of stable fracture patterns. New periarticular plates are replacing this implant in this area.
