Patient (pt) is a 61 year old woman with a history of muscle weakness and paralysis secondary to multiple sclerosis (ms).Pt also has a history of osteoporosis and has been a non-weightbearing wheelchair user since 2019.Pt used a device similar to the suspect device as part of clinical rehabilitation in prior years.On (b)(6) 2022, pt was prescribed the suspect device by a licensed physician, despite an extreme osteoporosis contraindication, and began using the device at home on (b)(6) 2022.The device is a wheelchair accessible stationary bike with integrated functional electrical stimulation (fes) for up to 10 muscle groups at once.This pt is mostly affected on the left side so uses the device with fes to the left erector spinae, abdominals, glutes, quadriceps, hamstrings, and tibialis anterior, along with right erector spinae and abdominals.The device times fes intensity in coordination with the cycling gait so that each muscle group actively works towards the movement, and the user controls the intensity limit.The device has an electric motor that assists or resists pedaling as needed to maintain a constant cadence of 35 revolutions per minute (rpm).The device also senses motor current to estimate cycle crank torque, and the device limits the torque it applies based on a user-selectable level.On (b)(6) 2022, the pt was using the device as usual and as intended, with help from a personal trainer.After a two minute passive warmup, the patient loaded preset fes intensity parameters from a past session.The device ramped up the stimulation from zero to the preset intensity (roughly 20% of maximum device output) over the next 3-5 seconds, while the motor continued to maintain the constant 35 rpm cadence.After four revolutions, the pt's active mechanical power output had increased to a peak of 49 watts.At this point, during a strong quadriceps muscle contraction elicited by the fes, the pt experienced an immediate, intense pain in the left knee.Within the same revolution, the device detected excessive resistance to pedaling and stopped pedal rotation and fes output.The excessive resistance was likely caused by the pt's reflexive response to the pain.The pt started a new session with low fes intensity and continued for nine minutes, but the pt could not tolerate the knee pain and ended the session.The pt contacted the device manufacturer, who recommended the pt immediately contact a physician to diagnose and treat the knee injury.The knee continued to be painful and began swelling, so the pt sought medical aid.The pt was admitted to a hospital the same day and had mri and x-ray imaging of the left knee.The mri showed hairline fractures in the distal femur and proximal tibia that could not be confirmed by x-ray imaging (occult fractures).Imaging did not show any other injuries.Pt is being kept in the hospital for inpatient rehabilitation, starting (b)(6) 2022.Pt knee has otherwise been immobilized and weightbearing is not permitted for 6 weeks while the fractures heal.
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