Osteoarthritic changes in the knee are a common cause of pain that restricts the subject's
ability to move and may lead to surgical intervention with total knee replacement.
Quadriceps muscle strengthening has been shown to improve the dynamic stability of the knee,
decreasing pain during locomotion and increasing knee function. However, the gains
associated with improved quadriceps strength have been difficult to achieve on a routine
clinical basis because the currently available ways to increase muscle strength- through
voluntary exercise or surface electrical stimulation- have significant practical problems
that limit their use. The aim of this prospective study is to evaluate the safety and
effectiveness of neuromuscular stimulation using implantable microstimulators called BIONs
to improve the strength, range of motion, and health of the knee in patients with knee
osteoarthritis. This investigation is expected to last 12 weeks for each study participant;
the trial will be completed over a 3-year period. Patients recruited into the study will
have advanced knee osteoarthritis for which total knee replacement surgery is being
considered. The proposed study extends a feasibility study carried out in Milan, Italy on
five patients with knee osteoarthritis, who were implanted with BIONs.
Knee Osteoarthritis is a common problem with people over the age of 50 and is often
debilitating because of the challenges it poses to normal walking function. Research has
shown that exercise can lessen the effect of the osteoarthritis in the knee if done
diligently. BION®s implanted in the thigh can produce contractions of the quadriceps muscles
without much movement of the knee joint, an advantage if moving the knee is painful. In this
study, teh subjects will be divided into three groups. Two groups of experimental subjects
will receive stimulation using BIONs. The first group will have a stimulation paradigm like
that used in a previous feasibility study that preceded the proposed trial, using
low-frequency (1-5 PPS) "twitch" stimulation. The second group will have a stimulation
paradigm in which tetanic-frequency stimulation (25-50 PPS) is used to produce fused muscle
contractions. A third group of experimental subjects will have a standardized program of
voluntary exercise.. In Groups 1 and 2, the femoral nerve will be stimulated electrically
according to the assigned protocol during the 12 week experimental period after implantation
of the devices. Individuals assigned to Group 3, receiving conventional exercise therapy
for 12 weeks, will be allowed to receive BIONs at the end of the trial, providing they
request BION therapy and they have been at least minimally compliant with the exercises.
All participants will be eligible to continue treatment following the initial 12 weeks if
medically appropriate and resources permit.
1. Subject presents with osteoarthritis of the knee with severity defined as
Kellgren-Lawrence grade 3-4.
2. Subject is between 18 and 75 years old.
3. Attending physician considers the subject in general good health (other than knee
4. Subject is mentally capable of understanding the goals and the application of
5. Subject is able to apply the therapy (with or without help) in the home setting.
6. Subject is willing and capable of giving informed consent.
7. Subject is willing and capable of traveling to testing center at the schedule
described above and detailed in Table 2.
1. Subject is pregnant, nursing, or planning to become pregnant in the next 12 months.
2. Subject has an electronic implant (e.g. cardiac pacemaker, etc.).
3. Subject has metallic implant (e.g. plates, hip joints) in the buttock or upper leg.
4. Subject has a history of falling.
5. Subject has medical conditions other than OA affecting the legs that could affect
treatment or mobility.
6. Subject is 40% or more above the ideal weight recommended by Metropolitan Life.
7. Subject has cancer.
8. Subject is currently enrolled in another clinical trial or research study that
involves therapy or intervention which would affect lower extremity mobility.
9. Subject has bilateral knee osteoarthritis.
10. Subject is taking pain medications with dosage not stable for one month.