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1st Nov


Muscle Deficits after Total Knee and Total Hip Replacement Surgery

In our physical therapy clinic in San Diego, as in typical practices around the world, we frequently see patients who have undergone total knee and total hip replacement surgeries. These surgeries have been shown to be amongst the most successful of all orthopedic surgeries performed today. However, several studies have shown that patients remain considerably weaker in the operated leg, as compared to the non operated leg.


A study by Shih and his team showed that one year after total hip replacement surgery, muscles in the operated hip were 11-16% weaker than in the non operated hip in men, and 19-21% weaker in women. Another study by Long and co-researchers showed significant residual muscle weakness in the operated hip up to two years following surgery.

Following knee replacement surgery, several researchers have reported 21-42% quadriceps weakness as compared to the non operated leg at 3 to 6 months after surgery, with a remaining 12-29% weakness at 1-2 years after surgery.

A recent study by Valtonen, and his Finnish coworkers revealed remaining significant leg weakness and atrophy, and loss of muscle power, an average of 10 months following total knee replacement. They agreed with other authors who have proposed that a knee extension power deficit can be associated with an increased risk of falling. Single leg balance has also been found to be significantly impaired on the operated leg one year following hip replacement surgery. Lack of leg muscle strength and power has also been associated with active mobility limitations, including the speed by which a person can negotiate stairs, and “get up and go” from a sitting position. The researchers out of Finland suggested that increasing muscle power of the operated leg ought be a central issue to address in rehabilitation.


It is quite common for patients to have physical therapy and perform exercise during the acute phase of rehabilitation, but more advanced programs long term are often lacking. This is in particular true following total hip replacement surgery. Therefore, many rehabilitation programs are not progressed sufficiently to result in significant enough strength gains. It should be remembered that many people go into the surgery already severely weakened due to prolonged pain and inactivity.


In our clinic, we use an exercise method termed Medical Exercise Therapy (also called Scientific Therapeutic Exercise Progressions), which addresses neuromuscular qualities such as coordination and proprioception (position sense), balance, endurance, strength and power. Such functional exercise can effectively and safely be prescribed to patients following joint replacement surgery, to restore normal function required for daily activities. We also agree with quoted authors in this letter, in that such training can greatly reduce a person’s risk of falling, and sustaining a potentially serious injury such as hip fracture.

We also instruct all our patients in an equally specific home rehabilitation program, to be performed for up to a year (or more, if desired), typically using a simple adjustable resistive home pulley apparatus. Patients who have the desire to return to an active lifestyle and enjoy improved quality of life, do very well with this rehabilitation approach.

With best wishes for a healthy and enjoyable Thanksgiving Holiday,


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