Case Study: Minimally Invasive Muscle Sparing Patient Specific Total Knee Replacement
By Brooke Smith, PT, DPT
AZOPT Goodyear Physical Therapist

Recently, I had the opportunity to observe a total knee replacement surgery performed by Dr. Brandon Gough, MD, of Hedley Orthopaedic Institute.  Dr. Gough performs a newer procedure that is less invasive with a shorter recovery time called “Minimally Invasive Muscle Sparing Patient Specific Total Knee Replacement.”  I know, say that 5 times fast!

In a nut shell, Dr. Gough replaces the entire joint of the knee with new components consisting of metal, polyethylene, or ceramics.  First, the damaged cartilage in the joint is removed.  Then, the end of the tibia (shin bone), femur (thigh bone), and patella (knee cap) is resurfaced and fitted with the new prosthesis.  This allows the joints of the knee – femur, tibia, and patella – to move against each other smoothly.  Dr. Gough reports that this “total knee replacement can be expected to provide pain-free movement for between 25-30 years and potentially longer”1.

There are major differences between this procedure and a traditional total knee replacement surgery.  They are:

The incision is smaller, usually 4-6 inches

A traditional total knee replacement/arthroplasty (TKA) surgery is typically 10-12 inches

No muscles are cut

In a traditional TKA, surgeons will cut through the quadriceps tendon, the large muscle of the thigh that attaches to the kneecap.

It is patient specific

Dr. Gough takes CT scans of the knee to create a model so he can customize the new implant (replacement and prosthesis) for each patient’s unique anatomy. “The pre-operative CT scan allows the surgeon to operate with greater accuracy, and results in a knee replacement that is more precisely shaped to fit the resurfaced bones.”1

After surgery, many patients are discharged from the hospital the next day, if not the same day.  All patients, both traditional and the minimally invasive technique, are expected to walk the same day of surgery.  Patients receiving the minimally invasive technique are shown to have fewer traumas to the soft tissues, muscles, and tendons surrounding the joint, which reduces the risk of surgical and post-operative complications1.  This also leads to shorter hospital stays, less post-operative pain and discomfort, and generally, a quicker recovery.  However, it is common to experience swelling and pain in the knee after surgery, especially after the anesthesia from surgery wears off.  This is still a major surgery; therefore, pain and swelling are normal.

So how do we know this new technique is more successful in leading to a quicker recovery and functional mobility?  My observation, education, and experience with many patients following different TKA surgeries lead me to believe this is the case.  But, let’s hear an account from a patient who received this minimally invasive technique with Dr. Gough.

Case Report

Patient is a 66-year-old female who is currently retired and living in Pebble Creek, an active adult community.  Prior to surgery, she reports more than 20 years of knee pain following a life filled playing sports – field hockey, basketball, and volleyball, to name a few.  She moved to Arizona in 2006 and loves participating in the community’s water aerobics, Zumba, tap dance, and golf.  She was forced to discontinue her activities due to increasing severity of knee pain in both knees.  She attempted to continue golf with knee braces, but still had lots of difficulty and pain.  Traditional pain medication, like ibuprofen, stopped working, and she began looking into alternative solutions to solve her knee pain.

In the beginning of 2014, she had arthroscopic surgery on both knees to replace the meniscu and remove bone chips.  While this helped for a short period of time, X-rays proved her knees were bone on bone, and eventually, she would need a knee replacement surgery.  In September 2014, during what should be a beautiful and peaceful river cruise through Europe, the pain was so severe that the decision was made then and there to seek a TKA.

Research into traditional knee replacements led her to alternative methods, specifically Dr. Brandon Gough at the Hedley Orthopaedic Institute.

On October 7, 2014 she had her left knee replaced at St. Lukes Hospital by Dr. Gough.  Her surgery was less than two hours.  She was walking the same day and returned home the next day.  Inpatient rehabilitation physical therapists prescribed a home exercise program (HEP), which she performed faithfully.  3 days after surgery, she arrived at AZOPT for the beginning of her outpatient physical therapy.

During her first visit, I was told she used a single point cane for walking when her post-surgical pain increased the initial day after surgery.  This is common when the initial anesthesia from surgery begins to wear off.  Since home, she was experiencing difficulty walking, sleeping, bending her left knee, and driving.   Her initial pain levels (0 is no pain, and 10 is emergency room pain) were reported as an 8 at worst and 4 at best.  She indicated that the pain was achy, with some sharp pain, and she had tightness along the left knee.  Rest, ice, and Tylenol helped improve her pain.

3 days after surgery, the patient’s initial knee range of motion measurements were as follows:

Knee flexion (bending):  65 degrees (the goal is 120 degrees)

Knee extension (straightening):  -10 degrees (the goal is 0 degrees)

She had increased swelling along the left knee above and below the joint, both normal after surgery.  During analysis of walking, it was determined she had a limp using a single point cane with decreased motion and time spent standing on left leg compared to her right leg.

As her physical therapist, I instructed her to perform increased knee bending and straightening stretches at home as well as the initial strengthening exercises I give every post-operative TKA patient.  I educated her on the importance of regaining knee motion, especially knee extension, to speed the return to normal activities of daily living and improve walking.

During the next treatment sessions, I performed manual therapy that included tissue mobilization (massage) to the muscles surrounding the knee and scar to reduce swelling and muscle knot.  This also helps reduce pain and improve motion.  Further, I stretched the knee into extension and to improve motion.   Lastly, I had the patient perform self stretches and progress strengthening activities, per the patient’s tolerance, to improve walking and return to normal activities.

On November 3, 2014, after 9 physical therapy visits, she had marked improvement in motion and strength.  She reported overall improvement of 75% after surgery with an average pain rating of zero.  If you remember from above, this means she was experiencing no pain at this time.  Her ranges of motion measurements were 120 degrees knee flexion and -4 degrees from full extension.  With me proving a passive stretch, she was able to achieve 130 degrees knee flexion and -2 from full knee extension.  Her strength improved and she could resist the moderate pressure I applied.  She was able to complete stairs and walk without using any cane or assistive device. She also reported being able to sleep throughout the night without waking due to left knee pain.

On November 18, 2014 the patient was recovered to the point she no longer needed physical therapy, and was subsequently discharged from AZOPT.  She would continue to perform her home exercise program while returning to normal recreational exercises and activities.

The patient attended Physical Therapy only 14 times for approximately one hour each session, and reported 85-90 percent improvement since beginning physical therapy.  She reported that occasionally she had pain as 1/10 but the majority of the time she had 0/10 pain. She continued to report stiffness in the left knee, which I explained is normal after surgery.  She was able to walk without any abnormalities and had 125 degrees knee flexion and 0 degrees knee extension.  These are the expected motion measures after a total knee replacement surgery.  Her strength also improved to equal the right leg and she was able to perform stairs, walk without limitations, and drive without difficulty.

This patient also had right knee arthritis and received the same knee replacement on the right knee in December 2014.  Upon returning to AZOPT post-surgery, she was received the same treatment with virtually the same results.  After one month of physical therapy, she was discharged from AZOPT and has since returned to golf and normal activities without limitations.

Sounds great, right?  Well, let’s offer some perspective on her results.

Regardless of the method of knee replacement, the expected range of motion is 120 degrees knee flexion and 0 degrees knee extension.  Physical therapy sessions will follow the same techniques – massaging, stretching, and strengthening to achieve the expected range of motion.  However, in most traditional TKA, the average patient achieves these results in 2-3 months.

This case study was the first of many patients I have treated with the new technique, and I saw much faster recovery of motion and quicker strength gains from her initial session to last session.  She was in Physical Therapy for a little more than one month (October 10, 2014 to November 18, 2014).  On average, patients I have seen following the Minimally Invasive Muscle Sparing Patient Specific Total Knee Replacements from Dr. Gough have achieved the expected range of motion faster than most TKA surgeries.

One important reminder – the healing process of a total knee replacement can take up to a year to fully recover following surgery.  Everyone is different and should not compare their recovery time to anyone else who has had the same surgery.  Everyone heals differently.  Even a person who has the right and left knee replaced can have a completely different recovery process with each knee.

Physical therapy helps the patient return to normal activities and mobility initially after surgery.  However, the patient must take responsibility to continue with their specific home exercise program provided by their physical therapist to maintain the benefits and results they received from physical therapy and prevent scar tissue formation or decline in function.


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