Trauma Update

Treatment of Acute Distal Femur Fractures

Brett D. Crist, MD; Gregory J. Della Rocca, MD, PhD; Yvonne M. Murtha, MD

  • Orthopedics
  • July 2008 - Volume 31 · Issue 7:
  • DOI:
An emphasis on indirect reduction techniques to restore limb alignment has improved the rate of fracture healing and decreased infection rates, fixation failure, and the need for bone grafting.

Distal femur fractures occur at approximately one-tenth the rate of proximal femur fractures and make up 6% of all femur fractures.1 There is a bimodal distribution of fractures based on age and gender. Most high-energy distal femur fractures occur in males between 15 and 50 years, while most low-energy fractures occur in osteoporotic women >50 years.1 The most common high-energy mechanism of injury is a traffic accident (53%) and the most common low-energy mechanism is a fall at home (33%).

Anatomy and Radiographic Evaluation

 
Figure 1: Axial CT scan showing the trapezoidal shape of the distal femur in the axial plane
Figure 1: Axial CT scan showing the trapezoidal shape of the distal femur in the axial plane.

Distal femur fractures involve the femoral condyles and the metaphysis.2 As with all fractures, understanding the deforming forces involved is critical for successful operative management. Shortening of the fracture with varus and extension of the distal articular segment is the typical deformity.3 Shortening is caused by the quadriceps and hamstrings. The varus and extension deformities are due to the unopposed pull of the hip adductors and gastrocnemius muscles respectively.

The most critical components of the femoral anatomy to understand for operative treatment of distal femur fractures include the shape of the articular block and the anterior bow of the femoral shaft. The distal articular segment has a trapezoidal shape on axial section (Figure 1). With both conventional and locked fixed-angle implants, unawareness of this geometry can lead to medialization, anterior displacement, and external rotation of the femoral condyles, articular penetration by implants, or excessive penetration of the medial cortex (Figure 2).3

The ability to recognize the normal anterior bow of the distal femur is important in fractures with metaphyseal comminution. Reducing the extension deformity can be challenging when using an intramedullary device, and the reduction can be difficult to evaluate when using a laterally-based plate construct (because the device obstructs fluoroscopic visualization).

Figure 2: Articular penetration of a locking screw
Figure 2: The lateral locking plate was not oriented to paallel the trapezoidal shape of the distal femur and resulted in articular penetration of a locking screw.
 

Oblique fluoroscopic views can help assess restoration of the anterior bow by allowing the anterior and posterior cortices to be visualized. Restoration of this normal anterior bow is important for both normal knee mechanics and accurate implant placement.

Adequate radiographic evaluation of distal femur fractures includes orthogonal plain radiographs of the entire length of the femur to avoid missing ipsilateral femoral neck or shaft fractures. Dedicated knee radiographs are required to screen for intra-articular extension of fracture lines. If intra-articular extension is suspected, a computeed tomography (CT) scan is warranted.4-6

Nork et al reviewed 202 distal femur fractures with intercondylar extension and demonstrated a 38% incidence of a coronal fracture involving the condyles (otherwise known as a Hoffa fracture).6,7 Eighty-five percent of the coronal plane fractures involved the lateral condyle and 9% involved both condyles.6 The importance of obtaining a preoperative CT scan is emphasized because 31% of the coronal plane fractures were not identified by plain radiographs alone. Identifying coronal plane fractures is critical for preoperative planning, with regard to both surgical approach and implant selection. In high-energy distal femur fractures that will undergo temporary external fixation until definitive surgery can be performed, it is helpful to obtain the CT scan after the knee-spanning external fixator is applied. The distraction and ligamentotaxis that the external fixator provides allows for easier visualization of fragments and more accurate preoperative planning.

Classification

The most common classification system used for distal femur fractures is the AO/OTA system (Figure 3).8 The distal femur is #33 in this system, and the fracture is then classified based on the amount of articular involvement and comminution. Type 33-A is an extra-articular fracture. Type 33-B is a partial articular fracture involving one of the femoral condyles. Type 33-C is a complete articular fracture. Each of the letter designations is further classified into 1, 2, or 3 based on the amount and location of comminution.

Figure 3: AO/OTA classification for distal femur fractures
Figure 3: AO/OTA classification for distal femur fractures. (Courtesy of the OTA).

Treatment Options

Once diagnosed, treatment decisions are based on both the characteristics of the fracture and patient factors. Treatment challenges are presented by patients with osteoporotic bone, open fractures with significant bone loss, and fractures with short articular segments.3

Nonoperative Treatment

Nonoperative treatment may be chosen for non- or minimally-displaced fractures in low-demand elderly patients. Nonoperative treatment may consist of either skeletal traction or initial splinting and mobilization with limited weight bearing and eventual transition to either a cast or functional brace. Radiographs are typically obtained at weekly to biweekly intervals for the first 6 weeks to ensure that the fracture reduction is maintained. Gradual progressive weight bearing and joint mobilization are allowed based on the clinical and radiographic progression of fracture healing.

In general, however, nonoperative treatment does not work well for displaced fractures. Butt et al9 performed a randomized control trial evaluating operative versus nonoperative treatment for displaced distal femur fractures in elderly patients. Patients were either randomized to operative treatment with a dynamic condylar screw (n=17) or skeletal traction for 6 to 8 weeks followed by functional bracing (n=19). Good or excellent results were obtained in 53% of the operatively-treated patients versus 31% in the nonoperative group. The nonoperative group had an increased risk for deep vein thrombosis (despite Coumadin therapy), urinary tract and pulmonary infections, pressure sores, nonunions, malunions, and pin tract infections. Mean length of stay for nonoperative patients was 9 weeks. For these reasons, Butt et al9 recommended operative treatment for displaced distal femur fractures in elderly patients. Therefore, nonoperative treatment for displaced fractures is reserved for those patients who cannot tolerate surgery.

Operative Treatment

Operative treatment is indicated for displaced fractures, open fractures, and those associated with a vascular injury. Treatment goals include anatomical reduction of the articular surface, restoration of limb alignment, early postoperative knee range of motion (important for articular cartilage nutrition), and early patient mobilization.

Initial management of distal femur fractures typically includes a well-padded long leg splint to improve patient comfort and prevent further soft tissue injury. In high-energy closed and open distal femur fractures, particularly in polytraumatized patients, some surgeons may temporarily stabilize the fracture with a knee-spanning external fixator until definitive management is possible.10-12 Not only does this restore crude overall alignment, prevent further soft tissue injury, and improve patient comfort and mobility, but it also allows a CT scan to be obtained for preoperative planning that is more useful as discussed above. Other options for temporary stabilization include a skeletal traction pin through the proximal tibia or calcaneus.

Multiple options exist for the definitive treatment of distal femur fractures and include external fixation, intramedullary nailing, and plate osteosynthesis with either open reduction and internal fixation or minimally invasive plate osteosynthesis. Likewise, multiple different plating options are available and include conventional buttress plates, fixed-angle devices, and locking plates.

External Fixation

External fixation is typically reserved for those patients with open fractures with bone loss, vascular injury, associated significant soft tissue injuries, or extensive comminution.13-17 Reported benefits of external fixation include decreased surgical time and blood loss, and less disruption of the blood supply to fracture fragments.14-16 Monolateral external fixation without spanning the knee,15,16 and circular or ring fixators have been most commonly used.13-15,17

For fractures with articular involvement, articular reconstruction is performed first, using either open reduction and limited internal fixation or closed reduction and percutaneous fixation with independent screws. Articular reconstruction is then followed by application of the external fixator. Occasionally, a knee-spanning component has been used initially to augment the distal segment fixation.15

Complications related to the use of external fixation for definitive treatment of distal femur fractures include septic arthritis, osteomyelitis, pin tract infection (thought to be due to the large soft tissue envelope of the femur), loss of reduction, delayed union or nonunion requiring bone grafting, and limited knee motion requiring either manipulation under anesthesia or quadricepsplasty.13-17 Most series have reported <10° of angular deformity and <3 cm of shortening in most fractures.13,14,16

Timing of external fixator removal may be difficult to determine in complex fractures. Time to bony union has been reported to require up to an average of 25 weeks.13,15 Furthermore, external fixator removal may require anesthesia and may lead to a risk of refracture. In a systematic review of acute distal femur fracture treatment with external fixation, Zlowodzki et al18 reported an average 7.2% nonunion rate, a 1.5% rate of fixation failure, a 4.3% rate of deep infection, and a 30.6% rate of secondary surgical procedures.

All of the case series reporting on external fixation have been small, mostly single surgeon series with <20 patients in each report. Additionally, the use of ring fixators is complicated by the fact that this technique is technically demanding and has a steep learning curve, as reported extensively throughout the literature.

Intramedullary Nailing

Intramedullary nail fixation is reserved for fractures with enough intact distal femur to allow for interlock fixation. The main indication for using an intramedullary nail is an AO/OTA type A fracture. However, both antegrade and retrograde nailing has been used successfully in the management of high-energy AO/OTA type C 1 and 2 fractures.3,19-22

As the retrograde intramedullary nailing technique has evolved, it has become more commonly used for distal femur fractures than antegrade nailing. This is likely due to the greater number of distal fixation options available with retrograde nailing. As with plating distal femur fractures, indirect fracture reduction and minimally invasive nailing techniques have also evolved.

Henry23 compared open versus percutaneous reduction techniques for retrograde nailing of distal femur fractures and showed improved postoperative knee function with decreased operative time, blood loss, bone grafting, and nonunion rates without differences in malunion rate using the percutaneous technique.

For open fractures, Cieslik et al24 reported on 39 fractures with and without articular involvement. Ninety-three percent of patients had bony union by 4 months after surgery. They concluded that retrograde nailing allows for early knee joint rehabilitation without increased risk of septic arthritis in patients with open distal femur fractures.

Several case series have also reported the success of the retrograde nail in low-energy fractures in elderly patients.25-28 In reviewing the series on retrograde nailing for distal femur fractures from 1989 to 2005, Zlowodzki18 reported an average nonunion rate of 5.3%, fixation failure rate of 3.2%, deep infection rate of 0.4%, and 24.2% secondary procedure rate.

Complications related to retrograde nailing include anterior knee pain,29 injury to the deep femoral artery with proximal locking,30 iatrogenic fracture of the femoral shaft,31 stress fracture above the implant,26 fatigue failure of the nail,28,32 intra-articular impingement of the nail,33 distal interlock bolt breakage,29,34 and varus malalignment requiring osteotomy correction.35

In elderly patients, limited weight bearing is recommended until callus formation is seen to avoid fixation failure.25-28 Newer retrograde nailing systems have multiple locking options for distal fixation and some can create a fixed-angle construct with the distal locking mechanism, which may allow for improved fixation and outcomes.

Due to the risk of inadequate distal fixation, antegrade nailing is typically reserved for AO/OTA type A fractures ≥5 cm above the articular surface,3 but its use has also been reported in AO/OTA type C1 and 2 fractures.3,19-22 The benefits of antegrade intramedullary nailing in these fractures include using a load-sharing implant, decreased surgical dissection of the fracture, avoiding the need for a large open arthrotomy, and avoiding the lateral thigh dissection associated with plating.23,28,30,34

Functional outcomes have been shown to correlate with patient age and severity of the initial injury.21 All studies that included fractures with articular involvement used closed or open reduction of the articular surface with supplemental fixation prior to nailing.19-21 To improve distal fixation, authors have recommend using longer nails with more distal positioning or cutting the distal end of the nail to allow for more distal placement of the interlock holes.19-21

To limit the risk of fixation failure, authors have recommended early limited weight bearing and selective use of bracing.23,28,30,34 In a more likely indication for antegrade nailing, Butler et al20 reported on 11 patients with ipsilateral femoral shaft and intra-articular distal femur fractures treated with an antegrade intramedullary nailing and supplemental articular fixation as needed. An arthrotomy was performed in all but 2 of the patients to verify articular reduction. The authors recommended using an arthrotomy in all cases with articular involvement. Four patients had nonanatomic articular reductions and 1 patient had a 20° extension malunion. The only relative contraindication for this technique was the presence of a coronal plane or Hoffa fracture of the articular surface. Three of the 11 patients had a coronal fracture and only 1 was noted intraoperatively.

Other reported complications with antegrade nailing in distal femur fractures include painful distal interlocking bolts,19,21 malunion,19-21 limb shortening >1 cm,19,21 and nail breakage.22 Of note, all reports on the use of antegrade nailing for distal femur fractures are from the early 1990s, prior to the widespread use of retrograde intramedullary nails. The systematic literature review of antegrade nailing for distal femur fractures by Zlowodzki et al18 revealed a nonunion rate of 8.3%, 3.7% rate of fixation failure, 0.9% infection rate, and 23.1% rate of secondary procedures.

For fractures with articular involvement, articular reconstruction is completed with screw fixation prior to intramedullary nailing. Careful preoperative planning is critical to ensure that the independent screws used for articular reconstruction do not obstruct the pathways of the intramedullary nail and the distal locking mechanism. One of the difficulties encountered when treating these fractures with intramedullary nails is obtaining and maintaining fracture reduction.

Regardless of nail diameter, the nail is smaller than the distal metaphysis of the femur. The nail does not reduce the fracture, and it can only maintain fracture reduction where it contacts the cortex. The fracture must first be reduced via either closed, percutaneous, or open reduction techniques.

Obtaining the correct starting point and proper placement of the starting wire for retrograde nailing is critical for the correct nail placement required to maintain the reduction. For antegrade nailing, guide rod positioning in the distal femur is critical. If the fracture is not reduced when these steps are accomplished, coronal and sagittal plane fracture malreduction is likely to be maintained by the implant. As reported by Krettek et al36 for tibia fractures, using a Pöller (blocking) screw in the metaphyseal area will create a false cortex for the nail to contact and can help maintain the fracture reduction when the nail is passed.

The Evolution of Plate Fixation

Conventional Plating

Plating of the distal femur has evolved significantly over the past 50 years. In the 1960s, 2 North American studies compared operative and nonoperative treatment of distal femur fractures. They concluded that nonoperative treatment was better and discouraged open reduction and internal fixation.37,38

Neer et al37 reported “satisfactory” results in 90% of nonoperatively treated fractures, stating that “no category of fracture at this level seemed well suited for internal fixation, and sufficient fixation to eliminate the need for external support or to shorten convalescence was rarely attained.” However, several reports in the 1970s and 1980s, using stricter outcome criteria, provided support for open reduction and internal fixation with 70% to 90% good or excellent results reported.39-53

Although operative treatment was gaining popularity in the 1970s and 1980s, the dissection required for open reduction and internal fixation with direct reduction of every metadiaphyseal fragment and absolute stability led to fracture fragment devascularization and an increased risk of delayed union, nonunion, infection, and implant failure when bone grafting was not done.3,48,54,55

The complications related to direct reduction techniques led to the development of indirect fracture reduction techniques, as reported by Mast et al.56 Concepts involved with indirect reduction techniques include reliance on soft tissue attachments to restore the mechanical axis, length, and rotation of the fracture without direct exposure of the fracture site, and the implant functions as an internal splint. The benefit is that the blood supply to the fracture fragments is maintained.3,55,56

In the 1990s, the success of these indirect reduction techniques for distal femur fractures were reported using conventional implants including the dynamic condylar screw, angled blade plate, and condylar buttress plate.48,57,58 Use of a lateral approach to the distal femur while avoiding direct fracture exposure and medial dissection led to early fracture callus formation and decreased implant failure rates, infection rates, and need for bone grafting except in open fractures with bone loss.3,55,59

To further decrease the risk of varus collapse and implant failure in fractures with significant medial comminution or osteoporosis, the addition of either a medial plate or an intramedullary plate was recommended.56,57,60 Supplemental use of a two pin medial external fixator has also been described.56,57 Successful use of these indirect techniques was reported by Bolhofner et al.57 Fifty-seven AO/OTA type A (22) and C (35) distal femur fractures were treated with either an angled blade plate (28) or condylar buttress plate (29). Eleven open fractures were included. The authors excluded type IIIB and C fractures61 since there was already significant damage to the fracture blood supply that violated the indirect technique. No bone grafting or dual plating was used in this series, and no hardware failures or nonunions were reported. The average time to union and full weight bearing was 10.7 weeks.

Although soft tissues and the periosteum can be handled carefully with large surgical exposures using indirect reduction techniques, the trend towards “biological plate fixation” continued and led to the development of minimally invasive plate osteosynthesis, also termed “minimally invasive percutaneous plate osteosynthesis.” These techniques were initially reported in the late 1990s by Krettek et al.55

Although minimally invasive plate osteosynthesis does not necessarily mean limited skin incisions, it includes indirect fracture reduction techniques for the metaphyseal and diaphyseal fracture components, limited lateral surgical dissection, passage of the plate submuscularly under the vastus lateralis in a retrograde fashion, and proximal screw insertion through small incisions through the muscle.55,58,62

Farouk et al63,64 demonstrated, in a cadaveric injection study model, that passing the plate submuscularly under the vastus lateralis preserved the perforating arteries and demonstrated superior periosteal and medullary perfusion when compared to the classic lateral approach to the femur, which elevates the vastus lateralis and variably disrupts the perforating arteries. In clinical series, this “biological plating” technique lowered the incidence of infection and implant failure, decreased the need for secondary bone grafting procedures, and led to earlier fracture callus formation, perhaps due to improved preservation of the periosteal blood supply.55,62-64

For distal femur fractures with articular involvement, the transarticular approach with percutaneous plate osteosynthesis has been used.55-62 When the articular surface is involved, anatomic reduction of the articular component is required. A lateral parapatellar arthrotomy is used to reduce the articular surface directly and fix the articular surface anatomically and rigidly, after which minimally invasive plate osteosynthesis technique is used to secure the articular block to the femoral shaft.55,62

Using a condylar buttress plate or dynamic condylar screw, Krettek et al62 prospectively evaluated the transarticular approach with percutaneous plate osteosynthesis technique in 8 AO/OTA C2 (2) and C3 (6) distal femur fractures (2 open). Average time to bone healing was 11.6 weeks. No nonunions, secondary bone grafting procedures, infections, or fixation failures were reported. average final knee range of motion was 5° to 138°.

For the metadiaphyseal portion of the fractures, the goals of both the minimally invasive plate osteosynthesis and transarticular approach with percutaneous plate osteosynthesis techniques are the same as indirect fracture reduction–to restore the mechanical and anatomical axes of the femur, the distal femoral angles, and length and rotation of the femur.62,65-68 However, due to the lack of direct visualization of the metaphyseal and diaphyseal areas, both techniques are technically demanding and require increased use of fluoroscopy to achieve adequate fracture reduction and restoration of limb alignment.55,62

Locked Plating

The next step in the evolution of plating distal femur fractures was the introduction of locking plates. Known as “locked internal fixators,” these devices create a fixed angle at each screw hole where the individual screw head is secured to the plate by different locking mechanisms. Since the plate does not depend on the friction created at the bone-plate interface to provide stability, the plate does not have to contact the bone directly that preserves the periosteal blood supply.55

Distal femoral locking plates are anatomically contoured and have multiple locking screw options distally to allow for secure fixation in the typical short condylar segment. The development of anatomically-contoured plates, with insertion jigs that allow for percutaneous insertion of the screws in the shaft of the plate, allows these systems to be more readily used in a minimally invasive fashion (Figure 4).55

Figure 4A: Distal femoral locking plate with aiming arm attached using minimally invasive techniques
Figure 4B: Incisions resulting from minimally invasive distal femoral locking plate technique
Figure 4: Distal femoral locking plate with aiming arm attached using minimally invasive techniques (A). Incisions resulting from minimally invasive distal femoral locking plate technique (B).

Locked implants are typically indicated in patients with osteoporosis, fractures with metaphyseal comminution where the medial cortex cannot be restored, or a short articular segment. Several case series have evaluated the use of locked implants in the treatment of distal femur fractures. The most commonly used implant in these case series has been the Less Invasive Stabilization System (LISS) (Synthes, Paoli, Pennsylvania) with unicortical locking screws.69-80

Zlowodzki et al18 combined these series (n=327) and evaluated the outcomes as part of a systematic literature review. Average nonunion, fixation failure, deep infection, and secondary surgery rates were 5.5%, 4.9%, 2.1%, and 16.2% respectively. Some of the technical errors that have been reported for fixation failure have involved waiting too long to bone graft defects, allowing early weight bearing, and placing the plate too anterior on the femoral shaft.70,71,75

Markmiller et al69 prospectively compared the outcomes of LISS and retrograde intramedullary nailing. At 12 months, no statistically significant differences were noted for nonunion, fixation failure, infection and secondary surgical procedures. However, this was a relatively small series and no power analysis was reported.

Currently, two basic types of locking plates exist. Unidirectional plating systems allow for a locking screw to be placed in one trajectory and typically use a threaded locking mechanism to create a fixed angle at the screw-plate interface. Multidirectional plating systems allow for the locking screw to be placed at variably-angled positions based on the locking mechanism used.

Likewise, different plating techniques can be used when using locking plates. The “locking” technique is where all of the screws are placed in a locked fashion after fracture reduction is completed, as was originally reported for the LISS.55,81,82

Continued development of locking plates led to implants that allow for bicortical locking screws as well as the ability to place compression and locking screws in the same plate. This capability led to the development of “hybrid” fixation. This technique uses nonlocked screws to either aid in coronal plane fracture reduction using the plate’s anatomic contour, compress the fracture site in simple fracture patterns, or for diaphyseal fixation that theoretically increase screw pullout strength.81-83 When using the plate as a reduction aid, the compression screw draws the bone towards the plate and uses the contour of the plate to reduce the fracture in the coronal plane (Figure 5). The plate does not aid in the sagittal plane reduction or restoration of limb length. These parts of the fracture reduction can be done with standard indirect fracture reduction techniques with either an external fixator, a femoral distractor, or manual or skeletal traction. Once the fracture is reduced, supplemental locking screws are then added to create a fixed-angle construct. The compression mode can also be used to address reduced articular fractures through the plate, or can be used in simple fracture patterns.

Figure 5A: After sagittal alignment and length were restored and provisional k-wire fixation of the distal articular block was done, the coronal plane is malreduced Figure 5B: A bicortical screw is placed through the anatomically contoured plate which reduces the coronal plane alignment as the screw pulls the bone towards the plate Figure 5C: Final AP view after placing locking screws Figure 5D: Healed distal femur fracture without bone grafting
Figure 5: An example of the hybrid fixation technique. After sagittal alignment and length were restored and provisional k-wire fixation of the distal articular block was done, the coronal plane is malreduced (A). A bicortical screw is placed through the anatomically contoured plate which reduces the coronal plane alignment as the screw pulls the bone towards the plate (B). Final AP view after placing locking screws (C). Healed distal femur fracture without bone grafting (D).

Biomechanical studies have shown that hybrid fixation is equivalent to the all locking screw technique. Gardner et al82 compared the biomechanical properties of compression plating, locked plating, and hybrid plating techniques in a osteoporotic synthetic humeral shaft fracture model. Hybrid and locked plate constructs had equivalent torsional stiffness and cyclic loading in torsion. Ricci et al84 compared axial stiffness, load to failure, and screw extraction torque for distal femoral locking plates with locked or nonlocked diaphyseal fixation in a nonosteoporotic and osteoporotic cadaveric supracondylar femur fracture gap model. Testing showed that locked diaphyseal fixation was only advantageous in the osteoporotic model.

The only clinical series to date that has evaluated a plate with the ability to use hybrid fixation in the distal femur was a report of clinical failures using the Locking Condylar Plate (Synthes).83 Forty-six fractures were treated using cannulated locking screws distally and bicortical nonlocked screws for diaphyseal fixation. Forty-three fractures resulted from high-energy mechanisms and 25 were open. Six of the 46 patients (13%) had implant failure. All of the failures occurred in AO/OTA type C3 fractures, with 4 of the 6 being open fractures, and with 3 of the 6 patients either having medical comorbidities or tobacco use as risks for diminished fracture healing potential.

Vallier et al83 concluded that locking plates should only be used when conventional fixed-angle devices cannot be placed. They also noted the significant added cost of locking plates. To decrease the risk of implant failure with locking plates, they recommended accurate fracture reduction and fixation along with judicious bone grafting, protected weight bearing, and modifications of the implant design.

Biomechanical Comparisons of Locking and Nonlocking Plates

Several biomechanical studies have compared conventional fixed-angle implants and locking plates in supracondylar (AO/OTA A3) fracture models. Marti et al85 compared the LISS plate with unicortical locking screws to the dynamic condylar screw and condylar buttress plate in axial loading and cyclic axial loading to failure in a cadaveric 1-cm fracture gap model. The LISS had more reversible and less irreversible deformation when compared to the other two constructs, which they attributed to the titanium composition and the unicortical screws.

Zlowodzki et al86 compared the LISS plate with unicortical locking screws to the 95° blade plate in axial, torsional, and cyclic axial loading in a cadaveric 1-cm fracture gap model. Under axial loading, significantly higher loads to failure, energy absorbed at failure, and displacement at load to failure were noted for the LISS plate. The blade plate was significantly stiffer in torsion. But, the LISS plate had significantly less permanent deformation under cyclic axial loading. They concluded that the LISS provided improved distal fixation in osteoporotic bone. In a 4-cm fracture gap model in high bone density cadaveric specimens, no significant difference was found between the LISS plate with unicortical locking screws and the angled blade plate for axial load to failure, but the LISS plate had significantly less axial stiffness.87

Higgins et al88 compared the Locking Condylar Plate, with distal locking screw fixation and bicortical locking and nonlocking diaphyseal fixation, to the angled blade plate in axial load to failure and cyclic axial loading in a cadaveric 1 cm fracture gap model. The locking construct had a significantly higher load to failure and less permanent deformation with cyclic loading. All of these studies reveal that locking plates with unicortical or bicortical diaphyseal fixation have adequate axial stiffness but more flexibility when compared to conventional fixed-angle implants. Although they have less torsional stiffness, the studies that evaluated torsional stiffness have shown that the distal fixation in locked implants is typically maintained while conventional fixed-angle implants have a higher rate of distal cutout from the femoral condyles.

Total Knee Arthroplasty

A dilemma still exists for elderly osteoporotic patients with poor fracture healing potential. Total knee arthroplasty (TKA) has been used in an attempt to solve this difficult situation and has been successful in one series. Rosen et al89 retrospectively reviewed the use of two different distal femoral replacement rotating hinge total knee prostheses in 24 ambulatory patients, averaging 76 years old. Twenty-three fractures were AO/OTA type C and one was type B. Five patients had pre-existing arthrosis. All patients had at least one major medical comorbidity. All patients regained ambulatory and full weight bearing status. Seventy-one percent of patients regained prefracture ambulatory aid requirements. No prosthetic loosening or revisions were reported with an average follow-up of 11 months (range, 5-23 months). They reported 1 superficial infection that resolved with antibiotics, 1 dislocation of the hinged prosthesis after a fall, and 1 cardiac-related death 13 months postoperatively. The reported benefits of this technique include early weight bearing and knee motion, fewer complications, and fewer revision surgeries than internal fixation. Although there was short-term follow-up and a small sample size, they concluded that primary TKA is effective in elderly patients with articular fractures and significant osteoporosis, pre-existing arthrosis, restricted lifestyles, and limited treatment expectations.

Review of the Evidence-based Literature

In 2006, Zlowodzki et al18 conducted a systematic review of the literature from 1989 to 2005 for operative treatment of acute distal femur fractures. Extensive database searches were done to identify the highest level of evidence. Case reports and articles with >30% periprosthetic fractures, nonunion revisions, and/or unicondylar fractures were excluded. The results were compared based on the type of fixation used and surgeon experience. Outcome parameters that were used include nonunion rate, fixation failure rate, deep infection rate, and secondary surgical procedures.

The levels of evidence for studies included in the meta-analysis ranged from 2 to 4. Only 1 randomized control study was identified that had methodological limitations (level 2) and compared operative versus nonoperative treatment. One prospective cohort observational study (level 2) compared the LISS plate and retrograde intramedullary nailing. Forty-five case series (level 4) made up the rest of the studies reviewed.

Evidence-based recommendations were given. A grade B recommendation was given for operative treatment over nonoperative treatment. Operative treatment reduced the risk of poor results by 32%. For the type of internal fixation used, a grade C recommendation was given. There were no observed differences between implants for nonunions, fixation failures, infections, and revision surgeries. Subgroup analysis showed that submuscular locked plating may reduce the rate of infection when compared to compression plating (55% relative risk reduction, P=.056), but at the increased risk of fixation failure and revision surgery. In addition, increased surgeon experience may significantly reduce the risk of revision surgery.

Summary

As the baby boomer population continues to age and high-energy mechanisms of injury continue to exist, distal femur fractures will continue to increase in incidence and complexity. The challenges faced in treating these fractures continue to include a short articular segment, bone loss in open fractures, and osteoporotic bone. As implants and techniques have evolved, the same treatment goals have remained; these include restoration of limb alignment, anatomic articular reduction, and early knee motion.

Emphasis on “biological” or indirect reduction techniques to restore limb alignment has improved the rate of fracture healing and decreased infection rates, fixation failure, and the need for bone grafting when compared to earlier clinical series that used direct reduction techniques.

Although the role of locking plates has continued to expand over recent years, clinical studies have yet to demonstrate a significant improvement in outcomes with their use. With that said, the development of locking plates has coincided with the advancement of minimally invasive plating techniques. As these newer implants continue to be used, large clinical trials are needed to validate their increased cost.

References

  1. Martinet O, Cordey J, Harder Y, Maier A, Buhler M, Barraud GE. The epidemiology of fractures of the distal femur. Injury. 2000; 31(suppl 3):C62-C63.
  2. Albert MJ. Supracondylar Fractures of the Femur. J Am Acad Orthop Surg. 1997; 5(3):163-171.
  3. Stover M. Distal femoral fractures: current treatment, results and problems. Injury. 2001; 32(suppl 3):SC3-SC13.
  4. Lewis SL, Pozo JL, Muirhead-Allwood WF. Coronal fractures of the lateral femoral condyle. J Bone Joint Surg Br. 1989; 71(1):118-120.
  5. Allmann KH, Altehoefer C, Wildanger G, et al. Hoffa fracture--a radiologic diagnostic approach. J Belge Radiol. 1996; 79(5):201-202.
  6. Nork SE, Segina DN, Aflatoon K, et al. The association between supracondylar-intercondylar distal femoral fractures and coronal plane fractures. J Bone Joint Surg Am. 2005; 87(3):564-569.
  7. Hoffa A. Lehrbuch der Frankturen und Luxationen. Stuttgart: Ferdinand Enke-Verlag; 1904.
  8. Fracture and dislocation compendium. Orthopaedic Trauma Association Committee for Coding and Classification. J Orthop Trauma. 1996;10(suppl 1:v-IX):1-154.
  9. Butt MS, Krikler SJ, Ali MS. Displaced fractures of the distal femur in elderly patients. Operative versus non-operative treatment. J Bone Joint Surg Br. 1996; 78(1):110-114.
  10. Iannacone WM, Taffet R, DeLong WG, Jr., Born CT, Dalsey RM, Deutsch LS. Early exchange intramedullary nailing of distal femoral fractures with vascular injury initially stabilized with external fixation. J Trauma. 1994; 37(3):446-451.
  11. Johnson KD HG. Distal femoral fractures. Orthop Clin North Am. 1987; 18(1):115-132.
  12. Ronen GM, Michaelson M, Waisbrod H. External fixation in war injuries. Injury. 1974; 6(2):94-98.
  13. Hutson JJ, Jr., Zych GA. Treatment of comminuted intraarticular distal femur fractures with limited internal and external tensioned wire fixation. J Orthop Trauma. 2000; 14(6):405-413.
  14. Arazi M, Memik R, Ogun TC, Yel M. Ilizarov external fixation for severely comminuted supracondylar and intercondylar fractures of the distal femur. J Bone Joint Surg Br. 2001; 83(5):663-667.
  15. Ali F, Saleh M. Treatment of isolated complex distal femoral fractures by external fixation. Injury. 2000; 31:139-146.
  16. Marsh JL, Jansen H, Yoong HK, Found EM, Jr. Supracondylar fractures of the femur treated by external fixation. J Orthop Trauma. 1997; 11(6):405-410.
  17. Ramesh LJ, Rajkumar SA, Rajendra R, Rajagopal HP, Phaneesha MS, Gaurav S. Ilizarov ring fixation and fibular strut grafting for C3 distal femoral fractures. J Orthop Surg (Hong Kong). 2004; 12(1):91-95.
  18. Zlowodzki M, Bhandari M, Marek DJ, Cole PA, Kregor PJ. Operative treatment of acute distal femur fractures: systematic review of 2 comparative studies and 45 case series (1989 to 2005). J Orthop Trauma. 2006; 20(5):366-371.
  19. Dominguez I, Moro Rodriguez E, De Pedro Moro JA, Cebrian Parra JL, Lopez-Duran Stern L. Antegrade nailing for fractures of the distal femur. Clin Orthop Relat Res. 1998(350):74-79.
  20. Butler MS, Brumback RJ, Ellison TS, Poka A, Bathon GH, Burgess AR. Interlocking intramedullary nailing for ipsilateral fractures of the femoral shaft and distal part of the femur. J Bone Joint Surg Am. 1991; 73(10):1492-1502.
  21. Leung KS, Shen WY, So WS, Mui LT, Grosse A. Interlocking intramedullary nailing for supracondylar and intercondylar fractures of the distal part of the femur. J Bone Joint Surg Am. 1991; 73(3):332-340.
  22. Wu CC, Shih CH. Interlocking nailing of distal femoral fractures. 28 patients followed for 1-2 years. Acta Orthop Scand. 1991; 62(4):342-345.
  23. Henry SL. Supracondylar femur fractures treated percutaneously. Clin Orthop Relat Res. 2000; (375):51-59.
  24. Cieslik P, Piekarczyk P, Marczynski W. Results of retrograde intramedullary nailing for distal femoral fractures - own experience. Ortop Traumatol Rehabil. 2007; 9(6):597-604.
  25. Armstrong R, Milliren A, Schrantz W, Zeliger K. Retrograde interlocked intramedullary nailing of supracondylar distal femur fractures in an average 76-year-old patient population. Orthopedics. 2003; 26(6):627-629.
  26. Kumar A, Jasani V, Butt MS. Management of distal femoral fractures in elderly patients using retrograde titanium supracondylar nails. Injury. 2000; 31(3):169-173.
  27. Janzing HM, Stockman B, Van Damme G, Rommens P, Broos PL. The retrograde intramedullary supracondylar nail: an alternative in the treatment of distal femoral fractures in the elderly? Arch Orthop Trauma Surg. 1998; 118(1-2):92-95.
  28. Gynning JB, Hansen D. Treatment of distal femoral fractures with intramedullary supracondylar nails in elderly patients. Injury. 1999; 30(1):43-46.
  29. Handolin L, Pajarinen J, Lindahl J, Hirvensalo E. Retrograde intramedullary nailing in distal femoral fractures--results in a series of 46 consecutive operations. Injury. 2004; 35(5):517-522.
  30. Handolin L, Pajarinen J, Tulikoura I. Injury to the deep femoral artery during proximal locking of a distal femoral nail--a report of 2 cases. Acta Orthop Scand. 2003; 74(1):111-113.
  31. Seifert J, Stengel D, Matthes G, Hinz P, Ekkernkamp A, Ostermann PA. Retrograde fixation of distal femoral fractures: results using a new nail system. J Orthop Trauma. 2003; 17(7):488-495.
  32. Iannacone WM, Bennett FS, DeLong WG, Jr., Born CT, Dalsey RM. Initial experience with the treatment of supracondylar femoral fractures using the supracondylar intramedullary nail: a preliminary report. J Orthop Trauma. 1994; 8(4):322-327.
  33. Danziger MB, Caucci D, Zecher SB, Segal D, Covall DJ. Treatment of intercondylar and supracondylar distal femur fractures using the GSH supracondylar nail. Am J Orthop. 1995; 24(9):684-690.
  34. Watanabe Y, Takai S, Yamashita F, Kusakabe T, Kim W, Hirasawa Y. Second-generation intramedullary supracondylar nail for distal femoral fractures. Int Orthop. 2002; 26(2):85-88.
  35. Ostermann PA, Hahn MP, Ekkernkamp A, David A, Muhr G. Retrograde interlocking nailing of distal femoral fractures with the intramedullary supracondylar nail [in German]. Chirurg. 1996; 67(11):1135-1140.
  36. 36. Krettek C, Miclau T, Schandelmaier P, Stephan C, Mohlmann U, Tscherne H. The mechanical effect of blocking screws (“Poller screws”) in stabilizing tibia fractures with short proximal or distal fragments after insertion of small-diameter intramedullary nails. J Orthop Trauma. 1999; 13(8):550-553.
  37. Neer CS II, Grantham SA, Shelton ML. Supracondylar fracture of the adult femur. A study of one hundred and ten cases. J Bone Joint Surg Am. 1967; 49(4):591-613.
  38. Stewart MJ, Wallace SL. Fractures of the distal end of the femur. J Bone Joint Surg Am. 1966; 48:784-807.
  39. Slatis P, Ryoppy S, Huittinen VM. AOI osteosynthesis of fractures of the distal third of the femur. Acta Orthop Scand. 1971; 42(2):162-172.
  40. Schatzker J, Home G, Waddell J. The Toronto experience with the supracondylar fracture of the femur, 1966-72. Injury. 1974; 6(2):113-128.
  41. Schatzker J, Lambert DC. Supracondylar fractures of the femur. Clin Orthop Relat Res. 1979; (138):77-83.
  42. Olerud S. Operative treatment of supracondylar--condylar fractures of the femur. Technique and results in fifteen cases. J Bone Joint Surg Am. 1972; 54(5):1015-1032.
  43. Chiron HS, Tremoulet J, Casey P, Müller M. Fractures of the distal third of the femur treated by internal fixation. Clin Orthop Relat Res. 1974; (100):160-170.
  44. Mize RD, Bucholz RW, Grogan DP. Surgical treatment of displaced, comminuted fractures of the distal end of the femur. J Bone Joint Surg Am. 1982; 64(6):871-879.
  45. Giles JB, DeLee JC, Heckman JD, Keever JE. Supracondylar-intercondylar fractures of the femur treated with a supracondylar plate and lag screw. J Bone Joint Surg Am. 1982; 64(6):864-870.
  46. Hall MF. Two-plane fixation of acute supracondylar and intracondylar fractures of the femur. South Med J. 1978; 71(12):1474-1479, 1481.
  47. Pritchett JW. Supracondylar fractures of the femur. Clin Orthop Relat Res. 1984; (184):173-177.
  48. Sanders R, Regazzoni P, Ruedi TP. Treatment of supracondylar-intracondylar fractures of the femur using the dynamic condylar screw. J Orthop Trauma. 1989; 3(3):214-222.
  49. Shewring DJ, Meggitt BF. Fractures of the distal femur treated with the AO dynamic condylar screw. J Bone Joint Surg Br. 1992; 74(1):122-125.
  50. Regazzoni P, Leutenegger A, Ruedi T, Staehelin F. [Initial experiences with the dynamic condylar screw in distal femoral fractures[in German]. Helv Chir Acta. 1986; 53(1-2):61-64.
  51. Siliski JM, Mahring M, Hofer HP. Supracondylar-intercondylar fractures of the femur. Treatment by internal fixation. J Bone Joint Surg Am. 1989; 71(1):95-104.
  52. Della Torre P, Aglietti P, Altissimi M. Results of rigid fixation in 54 supracondylar fractures of the femur. Arch Orthop Trauma Surg. 1980; 97(3):177-183.
  53. Wenzl HP CP, Hebert, Belin J. Die operative Behanlung der distalen Femufraktur. A0 Bulletin. 1970.
  54. Miclau T, Martin RE. The evolution of modern plate osteosynthesis. Injury. 1997; 28(suppl 1):A3-6.
  55. Krettek C, Muller M, Miclau T. Evolution of minimally invasive plate osteosynthesis (MIPO) in the femur. Injury. 2001; 32(suppl 3):SC14-23.
  56. Mast J JR, Ganz R. Planning and Reduction Technique in Fracture Surgery. New York, NY: Springer; 1989.
  57. Bolhofner BR, Carmen B, Clifford P. The results of open reduction and Internal fixation of distal femur fractures using a biologic (indirect) reduction technique. J Orthop Trauma. 1996;10(6):372-377.
  58. Krettek C, Schandelmaier P, Miclau T, Tscherne H. Minimally invasive percutaneous plate osteosynthesis (MIPPO) using the DCS in proximal and distal femoral fractures. Injury. 1997; 28(suppl 1):A20-30.
  59. Ostrum RF, Geel C. Indirect reduction and internal fixation of supracondylar femur fractures without bone graft. J Orthop Trauma. 1995; 9(4):278-284.
  60. Sanders R, Swiontkowski M, Rosen H, Helfet D. Double-plating of comminuted, unstable fractures of the distal part of the femur. J Bone Joint Surg Am. 1991; 73(3):341-346.
  61. Gustilo RB, Mendoza RM, Williams DN. Problems in the management of type III (severe) open fractures: a new classification of type III open fractures. J Trauma. 1984; 24(8):742-746.
  62. Krettek C, Schandelmaier P, Miclau T, Bertram R, Holmes W, Tscherne H. Transarticular joint reconstruction and indirect plate osteosynthesis for complex distal supracondylar femoral fractures. Injury. 1997; 28(suppl 1):A31-41.
  63. Farouk O, Krettek C, Miclau T, Schandelmaier P, Guy P, Tscherne H. Minimally invasive plate osteosynthesis: does percutaneous plating disrupt femoral blood supply less than the traditional technique? J Orthop Trauma. 1999; 13(6):401-406.
  64. Farouk O, Krettek C, Miclau T, Schandelmaier P, Tscherne H. Effects of percutaneous and conventional plating techniques on the blood supply to the femur. Arch Orthop Trauma Surg. 1998; 117(8):438-441.
  65. Krettek C, Miclau T, Grun O, Schandelmaier P, Tscherne H. Intraoperative control of axes, rotation and length in femoral and tibial fractures. Technical note. Injury. 1998; 29(suppl 3):C29-39.
  66. Krettek C, Miclau, T, Grun, O, Bastian, L, Tscherne, H. Techniques for assessing limb alignment during closed reduction and internal fixation of lower extremity fractures. Tech in Orthopaedics. 1999; 14(3):247-256.
  67. Paley D, Pfeil J. Principles of deformity correction around the knee [in German]. Orthopade. 2000; 29(1):18-38.
  68. Kregor PJ. Distal femur fractures with complex articular involvement: management by articular exposure and submuscular fixation. Orthop Clin North Am. 2002; 33(1):153-175, ix.
  69. Markmiller M, Konrad G, Sudkamp N. Femur-LISS and distal femoral nail for fixation of distal femoral fractures: are there differences in outcome and complications? Clin Orthop Relat Res. 2004; (426):252-257.
  70. Button G, Wolinsky P, Hak D. Failure of less invasive stabilization system plates in the distal femur: a report of four cases. J Orthop Trauma. 2004; 18(8):565-570.
  71. Schutz M, Muller M, Krettek C, et al. Minimally invasive fracture stabilization of distal femoral fractures with the LISS: a prospective multicenter study. Results of a clinical study with special emphasis on difficult cases. Injury. 2001; 32(suppl 3):SC48-54.
  72. Kregor PJ, Stannard J, Zlowodzki M, Cole PA, Alonso J. Distal femoral fracture fixation utilizing the Less Invasive Stabilization System (L.I.S.S.): the technique and early results. Injury. 2001; (32 suppl 3):SC32-47.
  73. Frigg R, Appenzeller A, Christensen R, Frenk A, Gilbert S, Schavan R. The development of the distal femur Less Invasive Stabilization System (LISS). Injury. 2001; 32 (suppl 3):SC24-31.
  74. Kregor PJ, Stannard JA, Zlowodzki M, Cole PA. Treatment of distal femur fractures using the less invasive stabilization system: surgical experience and early clinical results in 103 fractures. J Orthop Trauma. 2004; 18(8):509-520.
  75. Schandelmaier P, Partenheimer A, Koenemann B, Grun OA, Krettek C. Distal femoral fractures and LISS stabilization. Injury. 2001; 32(suppl 3):SC55-63.
  76. Weight M, Collinge C. Early results of the less invasive stabilization system for mechanically unstable fractures of the distal femur (AO/OTA types A2, A3, C2, and C3). J Orthop Trauma. 2004; 18(8):503-508.
  77. Syed AA, Agarwal M, Giannoudis PV, Matthews SJ, Smith RM. Distal femoral fractures: long-term outcome following stabilisation with the LISS. Injury. 2004; 35(6):599-607.
  78. Fankhauser F, Gruber G, Schippinger G, et al. Minimal-invasive treatment of distal femoral fractures with the LISS (Less Invasive Stabilization System): a prospective study of 30 fractures with a follow up of 20 months. Acta Orthop Scand. 2004; 75(1):56-60.
  79. Ricci AR, Yue JJ, Taffet R, Catalano JB, DeFalco RA, Wilkens KJ. Less Invasive Stabilization System for treatment of distal femur fractures. Am J Orthop. 2004; 33(5):250-255.
  80. Wong MK, Leung F, Chow SP. Treatment of distal femoral fractures in the elderly using a less-invasive plating technique. Int Orthop. 2005; 29(2):117-120.
  81. Wagner M. General principles for the clinical use of the LCP. Injury. 2003; 34(suppl 2):B31-42.
  82. Gardner MJ, Griffith MH, Demetrakopoulos D, et al. Hybrid locked plating of osteoporotic fractures of the humerus. J Bone Joint Surg Am. 2006; 88(9):1962-1967.
  83. Vallier HA, Hennessey TA, Sontich JK, Patterson BM. Failure of LCP condylar plate fixation in the distal part of the femur. A report of six cases. J Bone Joint Surg Am. 2006; 88(4):846-853.
  84. Ricci W, Zheng, Z, Jones, B, Cartner, J. Does Locked Plating Provide Improved Fatigue Properties over Nonlocked Plating and Does Bone Quality Matter? OTA Annual Meeting Poster Presentation Boston, MA; 2007.
  85. Marti A, Fankhauser C, Frenk A, Cordey J, Gasser B. Biomechanical evaluation of the less invasive stabilization system for the internal fixation of distal femur fractures. J Orthop Trauma. 2001; 15(7):482-487.
  86. Zlowodzki M, Williamson S, Cole PA, Zardiackas LD, Kregor PJ. Biomechanical evaluation of the less invasive stabilization system, angled blade plate, and retrograde intramedullary nail for the internal fixation of distal femur fractures. J Orthop Trauma. 2004; 18(8):494-502.
  87. Zlowodzki M, Williamson S, Zardiackas LD, Kregor PJ. Biomechanical evaluation of the less invasive stabilization system and the 95-degree angled blade plate for the internal fixation of distal femur Fractures in human cadaveric bones with high bone mineral density. J Trauma. 2006; 60(4):836-840.
  88. Higgins TF, Pittman G, Hines J, Bachus KN. Biomechanical analysis of distal femur fracture fixation: fixed-angle screw-plate construct versus condylar blade plate. J Orthop Trauma. 2007; 21(1):43-46.
  89. Rosen AL, Strauss E. Primary total knee arthroplasty for complex distal femur fractures in elderly patients. Clin Orthop Relat Res. 2004; (425):101-105.

Authors

Drs Crist, Della Rocca, and Murtha are from the Department of Orthopedics, University of Missouri, Columbia, Missouri.

Drs Crist, Della Rocca, and Murtha have no relevant financial relationships to disclose.

Correspondence should be addressed to: Brett D. Crist, MD, Department of Orthopedics, University of Missouri, MC213, One Hospital Dr, Columbia, MO 65212.

doi:

Healio is intended for health care provider use and all comments will be posted at the discretion of the editors. We reserve the right not to post any comments with unsolicited information about medical devices or other products. At no time will Healio be used for medical advice to patients.