Supracondylar Femur Fractures 

Updated: Oct 13, 2017
Author: Steven I Rabin, MD; Chief Editor: Jeffrey D Thomson, MD 

Overview

Background

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]

 

Presentation

History

Patients present with pain, deformity, weakness, and inability to use the leg. Elderly patients usually have a history of a fall. Younger patients usually have sustained high-energy trauma.

Physical Examination

Especially for the younger patient, in whom significant soft-tissue injury may also be present, careful assessment of the whole limb is required. Observation for compartment syndrome, vascular injury, and open wounds is warranted. Any fractures in other areas must be identified.

 

Workup

Imaging Studies

Patients with supracondylar femur fractures require anteroposterior (AP) and lateral radiographs of the entire femur to assess associated fractures and deformity; however, views centered at the knee are also important to assess the specific fracture pattern.

Staging

No specific staging system has been developed for supracondylar femur fractures; however, the Arbeitsgemeinschaft für Osteosynthesefragen (AO)-Association for the Study of Internal Fixation (ASIF) and Orthopaedic Trauma Association (OTA) classification systems help the surgeon determine appropriate treatment options.

The AO-ASIF classification divides supracondylar femur fractures into three main types, as follows:

  • A - Extra-articular
  • B - Partial articular
  • C - Complete articular

Type A is further divided into the following three subtypes:

  • A1 - Simple
  • A2 - Metaphyseal, wedge
  • A3 - Metaphyseal, complex

Type B is further divided into the following three subtypes:

  • B1 - Lateral condyle (sagittal fracture line)
  • B2 - Medial condyle (sagittal fracture line)
  • B3 - Frontal (coronal fracture line)

Type C is further divided into the following three subtypes:

  • C1 - Articular and metaphyseal segments, simple fractures
  • C2 - Articular simple, but metaphyseal multifragmentary fractures
  • C3 - Articular and metaphyseal segments, multifragmentary fractures
 

Treatment

Approach Considerations

Essentially all supracondylar femur fractures require operative intervention because of the severe potential risks of prolonged bedrest.

Patients in whom surgery is contraindicated include patients who are bedridden or nonambulatory with nondisplaced or minimally displaced fractures in which a brace may provide acceptable stability and alignment is not an issue. (Patients with displaced unstable fractures in this group still may require surgery to improve nursing care, decrease pain, and prevent further soft-tissue damage by mobile bone fragments.) Patients with severe life-threatening or other medical problems in which the risks of anesthesia are high may also be treated nonoperatively.

Medical Therapy

No specific medical therapy for supracondylar femur fractures exists. If the patient is unable to tolerate surgery, temporary traction can be used to maintain length and alignment (see the image below).

Supracondylar femur fracture treated in traction. 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.

For nondisplaced and stable fractures, bracing can provide enough stability to control pain and allow healing; however, bracing cannot control alignment or length because immobilizing the joint above and below is impossible.

Surgical Therapy

Surgical therapy involves reduction followed by fixation to maintain alignment. Options include external fixation and internal fixation. Internal fixation is accomplished by using intramedullary devices (eg, flexible rods, more rigid retrograde or antegrade rods) or extramedullary plates and screws.

Options for specific fracture types

The Arbeitsgemeinschaft für Osteosynthesefragen (AO)-Association for the Study of Internal Fixation (ASIF) classification, also incorporated into the Orthopaedic Trauma Association (OTA) classification (see Workup, Staging), allows rational choice of treatment options.[21]

For extra-articular distal femur fractures (A1, A2, A3) or those with condylar fragmentation (C1, C2), the standard of fixation is dynamic condylar screw (DCS) or 95° condylar blade plates (see the images below).[22, 23, 24]

Supracondylar femur fracture treated with a dynami 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.
Supracondylar femur fracture treated with a blade 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.

For condylar fractures (B1, B2, B3), a 4.5-mm T buttress plate is recommended.[24] Blade plates provide good rigid fixation, but the DCS is easier to insert, provides more interfragmentary compression across an intercondylar fracture, and more easily corrects sagittal plane malalignment.[7, 9, 10, 11, 12, 13, 23, 24, 25, 26]

For very distal fractures, the condylar buttress plate, which can be contoured to fit the distal femur and is strong enough to allow early motion, is often recommended, though occasional T or straight plates can be used (see the image below).[9, 22, 23, 27, 28, 29]

Supracondylar femur fracture treated with a suprac 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.

Alternatively, intramedullary devices may be used, including standard locked nails; supracondylar and retrograde nails; or Rush, Ender, and Zickel rods (see the images below).[22, 30, 31, 32, 33, 34, 35] Locked intramedullary nailing may be helpful for achieving fixation after failure of locked plating.[36]

Supracondylar femur fracture treated by retrograde 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.
Supracondylar femur fracture treated with Zickel f 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.

The Wagner external fixator has also been used.[37] In severely contaminated open fractures, external fixation with minimal internal fixation may be an option (see the image below).[6, 1, 37]

Supracondylar femur fracture treated with external 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.

These guidelines are useful in most supracondylar femur fractures; however, in severely comminuted complex (C3) fractures, rigid fixation of the multiple fragments may be challenging or impossible with standard implants. When blade plates, DCS plates, supracondylar rods, or standard interlocking rods are employed, the sites for distal screws must match the holes in the plate or rod and cannot be angled to find the best bone or avoid fracture lines. Multiple fragments anterior or posterior to the plane of the device cannot be secured.

The condylar buttress plate is the usual option because no entry portal exists, screws can be angled, and the plate can be easily molded to fit.[24] Even with this versatile plate, cases can occur in which most of the holes line up with fracture lines instead of intact bone; accordingly, the surgeon must be flexible when choosing the implant.

Cobra plates (see the first image below), designed for hip fusions, are strong implants that can provide solid screws in available bone. Tibial buttress plates actually designed for the tibia have been used (see the second image below). These nonstandard plates can provide fixation in situations where the standard implants do not fit the fracture pattern. Newer periarticular and fixed-angle plates are replacing the condylar buttress plate and making the use of nonstandard implants less necessary.

Supracondylar femur fracture treated with a cobra Supracondylar femur fracture treated with a cobra plate. This device is strong and can achieve fixation in multiple fragments but is not fixed angle.
Supracondylar femur fracture treated with a tibial 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.

Fractures above a total knee replacement may necessitate revision of the knee prosthesis, especially when it is loose.[38] Options are more limited because the surgeon must plan to avoid the prosthesis when placing the fixation implants. A stemmed revision implant sometimes may be used to replace the joint while it stabilizes the fracture. Preoperative planning and templating of radiographs is essential to choose the appropriate implant to use for fixation and is best done before the procedure.

In a meta-analysis of 29 case series with 415 distal femur fractures repaired with various fixation techniques, Herrera et al found that for periprosthetic supracondylar fracture, the rate of nonunion was 9%; that of fixation failure, 4%; that of infection, 3%; and that of revision surgery, 13%.[15] Retrograde nailing showed relative risk reductions of 87% for nonunion and 70% for revision surgery, compared with nonlocking plating. Risk reduction was also suggested for locking plates, though the relative reduction was not statistically significant. Relative risk reductions for nonunions and revision surgery were also significantly lower with retrograde nailing and locking plates than with nonoperative techniques.

Park and Lee compared 20 patients treated with retrograde nailing with 20 patients treated with minimally invasive plating for periprosthetic supracondylar frmoral fracture and concluded that although retrograde nailing had a slightly higher rate of nonunion, clinical outcomes showed no statistically significant difference.[39]

In a retrospective review of 25 patients treated with long retrograde intramedullary nailing for periprosthetic supracondylar femoral fractures following total knee arthroplasty, Lee et al reported that all 25 fractures were united (mean time, 12 weeks; range, 8-20 weeks), with good functional outcomes.[40] Loosening or breakage of distal interlocking screws was noted in three patients. At the time of final follow-up (mean duration, 39 months; range, 12-47 months), no deep infection or prosthesis loosening was observed.

Rahman et al studied 17 patients treated for periprosthetic supracondylar femoral fracture and determined that arthroplasty is a successful procedure. Four patients had complications. Two were treated without revision of the prosthesis; two required proesthetic revision.[41]

Matlovich et al reviewed the records of 57 patients and concluded that the use of intramedullary nails and the use of locked plate fixation produced comparable clinical outcomes.[42]

Shin et al reviewed eight studies of periprosthetic supracondylar fractures after total knee arthroplasty and also concluded that clinical outcomes, including nonunion and revision rates, were similar in patients who underwent locking compression plate fixation and those who underwent intramedullary nail fixation.[43]

Technical considerations

All the devices used to stabilize supracondylar femur fractures require exact placement of hardware for optimal rigid fixation. If the coronal and sagittal fracture lines intersect at the entry point of the blade, lag screw, or intramedullary device, fixation is insecure. Placement of the blade within 1.5 cm of the articular surface is crucial.[11, 23, 44]

The lag screw of the DCS also requires exact placement 2.5 cm proximal to the articular surface.[26, 45] The screw is 0.5 mm thicker than the blade and thus must be placed more proximally.[22] With both DCS and blade plates, one or more screws should be placed through the distal holes into the distal fragment for rotational stability.[23] A standard interlocking nail is not feasible with fractures that are too distal (< 7 cm from the joint) or with displaced intra-articular fractures unless the joint can be reconstructed with cannulated lag screws, because extensive intercondylar comminution prevents rigid fixation with these devices.[5, 9, 13, 46, 47]

Supracondylar nails also necessitate restoration of the condyles before nail placement.[30] Rush and Zickel devices must be inserted just proximal to the articular surface.[32, 33, 46] These flexible intramedullary devices may not provide adequate fixation.[5, 8, 27, 31, 46]

Use of any plate for supracondylar femur fractures requires strict adherence to AO-ASIF techniques, including interfragmentary compression, indirect reduction, preservation of soft-tissue attachments, and bone grafting. The surgeon must be aware of the trapezoidal shape of the distal femur and align the plate properly. Plates that do not match the metaphyseal flare must be molded to fit. When fixing these complex fractures, the surgeon must choose a device that fits the fracture, rather than try to make the fracture fit the device.

Surgical alternatives

Improved results are being obtained and expected with newer plate designs and techniques, including the following:

  • Bridge plating
  • Minimally invasive plating
  • Specially designed periarticular plates
  • Fixed-angle screw plates

Although technically, these approaches cannot be considered future developments, because they are currently being used, they are not yet widespread; it is expected that they will be used more extensively as surgeons gain experience with them.

Bridge plating involves bypassing the fracture site when the plate is applied to minimize soft-tissue disruption and disruption of the fracture hematoma, which contains osteoinductive factors. By using indirect reduction techniques, the chances of nonunion and infection are reduced.

Minimally invasive techniques include bypassing the fracture site and using smaller incisions that decrease the surgical trauma. Plates are slid along the bone under the soft-tissue envelope.

Periarticular plates have been designed by many manufacturers to better fit the shape of the distal femur so that less or no contouring of the plate is required.

Fixed-angle screw plates (eg, Less Invasive Stabilization System [LISS; Synthes, West Chester, PA] and Combi plates) allow the surgeon to place multiple screws (as with the supracondylar buttress plate) to avoid fracture lines in comminuted fractures, while decreasing the chance of loss of reduction from settling of the screws.[48] (In the supracondylar buttress and other standard plates, screws can toggle in the holes of the plate because they are not rigidly attached to the plate. In the fixed angle screw plates, the screws are screwed into the plate hole, preventing them from toggling.)

The use of the LISS plate, which is also designed for minimally invasive placement, is controversial but gaining in popularity. In a randomized study of 42 patients, Gill et al concluded that although nailing may be more cumbersome intraoperatively, LISS results in a greater number of technical errors and is less forgiving.[49]

It is important to use the device that fits the fracture and to use careful surgical technique to obtain optimal results. Be flexible, but plan carefully.

Postoperative Care

During fixation of supracondylar femur fractures, the surgeon must assess the stability of fixation and the quality of the bone.

If the fixation is solid and the bone quality is good, some patients can be allowed early weightbearing and motion, especially when intramedullary fixation is used. If bone quality is good but not good enough to allow early weightbearing, the patient may be placed in a hinged knee brace to allow early motion but kept off full weightbearing until radiographs show bone healing (at ~12 weeks). If bone quality is poor, more rigid splinting may be required for about 6 weeks and then switched to a hinged brace. Postoperative physical therapy is usually required.

Patients need to be monitored until the bone is healed.

Complications

Complications of supracondylar femur fractures include the following:

  • Nonunion, often with hardware removal
  • Loss of alignment (malunion)
  • Infection
  • Medical complications (eg, thromboembolic disease)