Clinical Problem

Femur fractures are a common injury among the population, with an incident rate of femoral shaft fractures is 9.5 to 18.9 per 100,000 annually. This translates to approximately 250,000 annual fractures in the United States, a number which is expected to double by 2050. The incidence of femur fractures also increases with age, and elderly patients often experience femur fractures from lower energy impacts, such as falling from standing height. ¹ Following a femur fracture and the subsequent surgical repair, use of an assistive device is necessary for independent ambulation. However, canes, walkers, and other common mobility aids rely heavily on the user's upper body strength, which decreases significantly as you age - as much as 40% by the age of 40.¹ In some instances, transferring weight to the upper body risks further injury, so patients cannot use these devices to ambulate independently after a femur fracture. Numerous elderly patients also report canes and walkers as being difficult to use, and many don’t utilize them as a result. In one study, forty-two of sixty-nine elderly participants reported problems with their walkers, with 57% of them citing walkers as difficult and dangerous to use. Other common complaints include the introduction of circulation issues, arthritis, and compounding heart and blood pressure complications.² Similarly, out of 157 subjects, 105 reported issues with canes, and 89 do not use canes anymore due to the issues they experienced. The most commonly cited issues with cane usage include difficult and risky use, insufficient support, and arthritis.³

Another significant issue with many assistive tools is that the surgically repaired femur takes no load throughout the period of recovery. While it is important for the femur to experience no load directly following the injury, the newly formed bone structure will be weaker if the femur is isolated throughout the entire healing process. This occurs because bone cell modeling and remodeling is largely dictated and altered by how much force a bone experiences over a period of time. When a bone experiences lower levels of loading through inactivity, the resulting bone structure after reformation will be weaker and more susceptible to future breaks. If the femur bears no weight throughout the healing process, the reformed bone may not be strong enough to support the patient’s body and patients may need to go to physical therapy in order to return the bone to full strength. This lengthens the recovery process, which is frustrating for patients who want to regain their independence after the injury.⁴