Early Weight Bearing on Supracondylar Distal Femur Fractures in Elderly Patients

Supracondylar femur fractures represent 4-7% of femur fractures. These are a common
orthopaedic injury with an overall incidence of 37 per 100,000 person-years. These fractures
are complex and challenging for orthopaedic surgeons. The fracture needs to be correctly
reduced and, like nearly all fractures, fixed with enough stability to permit early joint
motion. This allows for earlier patient rehabilitation, which can improve outcomes. There are
a number of different fixation devices. Fixed angle implants such as retrograde
intramedullary nails, angled blade plates, and 95-degree side plates have had good clinical
outcomes with resistance to varus collapse. Recently, locking plates have become the standard
method for distal femoral fracture fixation. Hendersen et al. provided a systematic review of
locking plate fixation and demonstrated the range of complications as 0% to 32% and implant
failure occurring late with 75% of failures occurring after 3 months and 50% occurring after
6 months. Ricci et al. sought to determine risk factors associated with failure of locked
plate fixation of distal femur fractures and found that 19% required reoperation. The risk
factors for reoperation found in this study were diabetes, smoking, increased body mass
index, shorter plate length and open fracture. Most factors are out of surgeon control but
are important to evaluate when considering prognosis.

After the fracture has been open reduced and internally fixed, there is debate on
postoperative management of weight bearing. Weight bearing following fixation is generally
restricted for 6 to 12 weeks until radiologic evidence of evidence demonstrates sufficient
callous. This restricted weight bearing is primarily due to concerns of implant failure and
loss of reduction. A study by Brumback et al. examined intramedullary nail fixation of distal
femur fractures and concluded to allow full weight bearing of comminuted femoral shaft
fractures with antegrade intramedullary nail. This study led surgeons to accelerate their
rehabilitation protocols.

The post-operative weight bearing recommendations for distal femur fractures treated with
locking plate vary widely which motivated Granata et al. to evaluate the biomechanics of
immediate weight bearing of distal femur fractures treated with locked plate fixation. They
found that the fatigue limit of the locked plate constructs was 1.9 times body weight for an
average 70-kilogram patient over a simulated 10-week postoperative course. Although this
study could not fully support immediate weight bearing due to the fact that femoral loads
during gait have been estimated to be around 2 times body weight, it demonstrated adequate
hardware fixation with weight bearing.

The benefits of early weight bearing are accelerated functional recovery, increased
independence, decreased impact on the family, increased psychological benefits, reduced use
of healthcare resources, decreased need for family intervention, and family to take care of
the patient. The downside is the strength of fixation, the risk of implant failure, and the
risk of loss of reduction. The goals are to evaluate the fracture, the complication rate, the
mortality rate, and the risks of healthcare resources that have been used.

Inclusion Criteria:

- Distal femur fractures, including periprosthetic fractures

- AO/OTA classification 33

- Above 64 years of age and below 90 years of age

- Household ambulators: defined as an individual who can walk continuously for distances
that are considered reasonable for walking inside the home but limited for walking in
the community due of endurance, strength, or safety concerns

Exclusion Criteria:

- Those who do not fit the inclusion criteria

- Concomitant ipsilateral lower extremity injury

- Contralateral lower extremity injury.

- Vascular injury of concomitant lower extremity requiring repair

- Pathologic fracture

- Definitive treatment delay of more than 2 weeks from initial injury

- Unable to comply with post-operative rehabilitation protocols or instructions

- Current or impending incarceration