Effects of Kneehab 12-week Peri-operative Total Knee Arthroplasty

Determine the efficacy of neuromuscular electrical stimulation (NMES, Kneehab) in promoting accelerated recovery of quadriceps function in patients recovering from total knee arthroplasty (TKA) as measured by increases in isometric strength of the knee extensors and scores in the Timed Up and Go (TUG) test.

Knee osteoarthritis is a severe debilitating condition that greatly impacts patient quality of life, function, emotional well-being and everyday pain levels. Total knee arthroplasty (TKA) is performed as a means of alleviating these symptoms in the long term however short term muscle weakness following surgery can elicit its own detrimental effect on performance and activities of daily living. This underlines the importance of mitigating strength loss in the immediate post-operative period.

Recent reviews suggest that Neuromuscular Electrical Stimulation (NMES) of the quadriceps femoris muscle can be beneficial in the rehabilitation period following knee surgery. It appears that early use of NMES can help to recover exercise capacity in the muscle, thus allowing the patient to benefit more from volitional exercise therapy later in the rehabilitation period1. This in turn can lead to accelerated recovery and improved outcomes. A recent and as yet unpublished study of 96 patients following ACL reconstruction has demonstrated a clear benefit to the use of Kneehab. The benefit seemed to accrue in the six-week post-operative period.

A recent pilot study by Walls 2 also suggests that NMES applied in the immediate pre-operative period before TKA leads to increased muscle strength and improved functional abilities. Previously, Mizner (2005) has shown pre operative strength to be a good predictor of functional outcome 1 year after surgery3. This proposed study aims to examine whether NMES applied in the peri-operative timeframe, 6 weeks before and 6 weeks after, can improve outcomes for patients undergoing total knee replacement. The rationale for this approach is that NMES can help prepare the quadriceps muscle for the rehabilitation phase by building exercise capacity before the operation. The immediate deficit, which normally follows knee surgery, would therefore be compensated to some extent and the post-operative NMES treatment would be expected to counteract the activation inhibition that is thought to occur in the early weeks following surgery. Overall, the patient would be in a better position to benefit from conventional rehabilitation exercises aimed at improved co-ordination and functional performance.

Eligibility Criteria:
Inclusion Criteria:

* Individuals who are scheduled for elective Total Knee Replacement surgery
* Individuals who are at least 18 years of age
* Individuals with a body mass index (BMI) \<40
* Individuals who are walking independently with or without assistive devices
* Must be able and willing to complete all study assessments and to be followed for the full course of the study.
* Must be able to read, write and follow instructions in English.
* Must be able and willing to provide informed consent.
* Must be willing and able to attend for pre-op assessment

Exclusion Criteria:

* Individuals who have failed the pre-operative assessment
* Individuals with a history of foot and/or ankle pathology
* Individuals with a history of tibial or femoral fractures
* Individuals with a history of underlying neurological conditions
* Individuals with physical conditions which would make them unable to perform study procedures
* Individuals with a total hip replacement
* Individuals undergoing revision TKA of the same operated leg
* Pregnant women or inadequate precautions to prevent pregnancy
* Diagnosis of a medical condition that would contraindicate treatment with the product,e.g skin lesions at electrode site.
* Individuals with an active implanted medical device (i.e. pacemaker, pump)
* Individuals with a history of stroke
* Individuals with a history of neurological disorder that affects lower extremity function (stroke, peripheral neuropathy, Parkinson's disease, multiple sclerosis, etc.)
* Individuals with a diagnosis of inflammatory arthritis (including Rheumatoid Arthritis, gout or psoriatic arthritis)
* Individuals with muscle disease (i.e. muscular dystrophy)
* Visible skin injury or disease on their legs
* Principal investigator for this study, or member of study staff