Controversies persist for treating distal femoral fractures

In the past, the implants available to stabilize fractures of the distal femur (AO/Orthopaedic Trauma Association classification 33) were limited to retrograde nails, 95-degree blade plates, dynamic condylar screws, distal femoral plates, and standard 6.5 mm cancellous screws. Over time, fixation has improved dramatically, and two of those implants are not available anymore. When the less invasive stabilization system (LISS) was released in the early 2000s, many trauma surgeons hoped that the numerous problems associated with these fractures would be resolved — but that did not occur. Even after significant development in the treatment of distal femoral fractures, surgeons continue to fight issues of nonunion, hardware failure, malalignment, and stiffness. Several controversies persist regarding these injuries and fixation methods.

Addressing nonunion and construct stiffness
The relatively high incidence of nonunion (up to 19%) remains a frequent concern for healthcare professionals caring for patients with these injuries. After sagittal malalignment is reduced, a large anterior metaphyseal bone defect often remains due to the extensive comminution present. Even after the introduction of locking implants, distal femoral nonunions persisted, and the idea that “maybe the construct is too stiff” began to emerge. Before long, tactics to decrease the rigidity of the fixation began to enter the conversation.

To address the issue of excessively stiff constructs that arose following treatment with locked plating, surgeons began to blame the use of excessive numbers of diaphyseal screws and short working lengths as contributors to nonunion. According to the concept of “working length,” by allowing a longer, unfixed portion of the plate to span the fractured area, the stress on the fixation is spread over a greater area of the plate. This encourages more micromotion and decreases the risk of premature hardware failure. Shorter constructs with more screws in the injured segment decrease the working length, increase construct stiffness, and increase strain on the fixation.

In addition to ensuring long working length and reduced screw density, researchers began to contemplate the idea of “far cortical locking.” Because far cortical locking screws engage only the far cortex (medial cortex) of the femur, researchers anticipated that the construct would lead to decreased stiffness by allowing increased micromotion.

However, in their randomized trial of 167 patients, Lefaivre et al. found similar clinical outcomes and healing between the standard care group and the far cortical locking group. Radiographic and clinical healing did not differ significantly between the two groups, and the proposed advantages of far cortical locking observed in biomechanical and animal studies were not realized in human clinical trials. Acknowledging that this theory did not solve patients’ fixation issues, the authors emphasized the practice of working length, screw density, and flexible constructs. They suggested that far cortical locking should be considered along with these other best practices.

Combined retrograde nailing plus locking plates
Eventually, the concept of combining retrograde nails and lateral locking plates to stabilize distal femoral fractures was considered. On the surface, this idea may seem counterintuitive, as combining these methods would seem to make the fixation stiffer — accentuating the aforementioned problem. Fontenot and colleagues studied the in vitro stiffness of this combined system and found that a laterally based fixation construct became biomechanically superior after supplementation with either an additional medial plate or intramedullary nail. In their biomechanical study, Lin et al. found that the internal fixation plate contributed most of the axial and torsional stiffness in their nail-plate constructs. In their systematic review and meta-analysis, Baumann and colleagues found that the nail-plate combination was superior to conventional fixation in terms of reducing complications and unplanned reoperations. Likewise in their meta-analysis, Daher and coauthors found similar results with nail-plate combinations being superior in complications, reoperations, implant failures, malunion, nonunion, and earlier weight-bearing on the affected limb.

Dekeyser and coauthors compared mortality and complications after operative repair or distal femoral replacement for distal femoral fractures. They found that patients treated with distal femoral replacement had higher rates of readmission, infection, pulmonary embolism, and device-related complications during the first year.

Determining value
In the modern day, none of these surgical decisions should be deliberated without consideration of the value paradigm. The massive cost associated with healthcare in the United States requires all clinicians to be good stewards of the resources that they influence. As a result, the question remains: Do the benefits associated with nail-plate, dual-plate, or distal femoral replacement outweigh the increase in cost associated with these constructs? Though the combined constructs reduce reoperation and improve function, no payers currently reimburse systems for the increased expense associated with these treatments. Until Medicare can effectively reimburse the increased costs associated with these tactics, the cost of this increase in quality is borne by the hospital system.

Douglas W. Lundy, MD, MBA, FAAOS, is chair of orthopaedic surgery and chief of orthopaedic trauma surgery at St. Luke’s University Health Network. Dr. Lundy is a member of the AAOS Now Editorial Board.