Knee Arthritis & MISHA Implant
What Is Knee Arthritis?
Knee arthritis is the gradual wearing away of the cartilage that cushions your knee joint, causing pain, stiffness, and swelling as bone increasingly grinds against bone. It's a progressive condition, and treatment typically follows a pathway: starting with non-surgical care, moving to joint-preserving options like the MISHA Implant for appropriate candidates, and, for more advanced or end-stage arthritis, total knee replacement. Dr. Thon focuses on the non-surgical and joint-preserving side of that pathway, and will refer you to a trusted colleague if and when a full replacement becomes the right option for you.
This is you if:
- You've been told you're not ready for a knee replacement, but you're still in real pain
- You have knee pain from arthritis on the inner (medial) side of your knee that limits your daily activities
- You've already tried NSAIDs, injections, physical therapy, or an off-loader brace without lasting relief
- You want to preserve your natural knee for as long as possible before considering replacement
- You want an honest assessment of where you actually are on the arthritis treatment pathway
Symptoms
- Pain concentrated on the inner (medial) side of the knee — this is the location most associated with MISHA candidacy; pain elsewhere in the knee often points to a different underlying cause
- Knee pain that worsens with activity, especially walking, stairs, or standing for long periods
- Stiffness, particularly after sitting or first thing in the morning
- Swelling around the knee
- A grinding or grating sensation with movement
Causes & Risk Factors
- Osteoarthritis — gradual wear of the joint cartilage over time, and the most common cause
- Prior knee injury — including meniscus tears or ligament injuries that go on to accelerate joint wear
- Excess body weight — increases the load carried through the knee with every step
- Genetics and joint alignment — some people are naturally more prone to arthritis based on how their knee is aligned
Non-surgical first.
Non-surgical treatment is almost always the starting point, and several options can be layered or sequenced depending on how you respond:
- Conservative Management — Rest, activity modification, over-the-counter anti-inflammatory medication (NSAIDs, Tylenol), ice/heat, and a structured home exercise program, along with weight loss when appropriate. Typically tried for 4-6 weeks before considering anything more involved.
- Physical Therapy — Strengthens the muscles supporting your knee to improve stability and function. Most patients attend 1-2 times per week for at least 6-8 weeks.
- Corticosteroid Injections — A powerful anti-inflammatory injected directly into the knee, working within 3-5 days and providing relief for 2 months or more. Generally limited to every 4-6 months to protect the joint's cartilage.
- Platelet-Rich Plasma (PRP) Injections — Uses concentrated healing factors from your own blood to reduce inflammation. Effects can last 6-12 months in responsive patients, though results vary.
- Cryoneurolysis (Iovera, Coolief) — A minimally invasive treatment that uses controlled cold therapy to temporarily quiet the nerves sending pain signals from your knee. Relief typically lasts 3-6 months and can be repeated as needed.
Knee Arthroscopy.
Arthroscopic surgery can remove damaged meniscal tissue and relieve mechanical symptoms like catching or locking, but it doesn't treat the underlying arthritis itself. Outcomes tend to fall into thirds: about a third of patients get significant relief, a third get only mild improvement, and a third see little to no benefit. It's most predictable for mild-to-moderate arthritis with clear mechanical symptoms, not when arthritis pain itself is the main problem.[5]
MISHA Implant — a joint-preserving alternative to replacement.
For patients whose medial knee arthritis hasn't responded to conservative treatment, but who aren't ready for, or don't want, a full knee replacement, the MISHA Implant is an outpatient, minimally invasive option.[1][2] It's an implantable shock absorber, placed through a single incision along the inner side of your knee, outside the joint capsule. It doesn't remove any bone or cartilage, doesn't restrict your weight-bearing or range of motion, and can even be combined with other knee procedures, like a meniscus repair, when needed.[2] Because it's placed outside the joint, it preserves all of your future surgical options, including a knee replacement later, if you ever need one, unlike a replacement, which is a far more invasive, irreversible procedure.[1] In carefully selected patients, up to 75% report significant improvement.[5]
Best candidates generally have: early to moderate arthritis limited to the inner (medial) side of the knee, good overall knee alignment, a BMI under 35, and have failed conservative treatment.[2][5]
Not suitable for: “bone-on-bone” arthritis affecting the entire knee, rather than just the inner side. If your bone-on-bone arthritis is limited to the medial compartment, MISHA can still be an option, though you should expect less relief than a patient with earlier-stage arthritis. A BMI under 35 is best for candidacy, and a BMI over 40 rules out the procedure entirely. MISHA also isn't suitable for inflammatory arthritis like rheumatoid arthritis, active infection, poor bone quality, poor alignment, or a previously failed knee replacement. [1][2][5]
Total Knee Replacement.
For more advanced or end-stage arthritis, total knee replacement remains the definitive treatment, and an important part of the overall arthritis pathway. Dr. Thon doesn't perform knee replacements himself; his focus is on preserving your natural knee for as long as realistically possible. When a replacement is genuinely the right next step for you, he'll tell you honestly and refer you to a trusted joint replacement specialist for that procedure.
Recovery & What to Expect
- Surgery: Typically 2-3 hours, performed as an outpatient procedure under local anesthetic and a nerve block, using an opioid-sparing pain protocol.[2]
- Weight-bearing: Immediate — unlike most knee surgeries, you can put weight on your leg right away, as tolerated. Crutches are provided for comfort and safety early on.[2]
- Physical therapy: Begins within 3-5 days after surgery, focused first on regaining motion, walking mechanics, and quad activation.[2][3]
- Dressings & incision care: Outer dressings come off after 48 hours; incisions shouldn't be soaked (baths, pools, hot tubs) for 3-4 weeks.[2]
- Follow-up visits: You'll be seen 6 times after surgery, spaced with gradually increasing time between visits over the following year.[2]
- Return to activity: Swimming, cycling, and golf around 4-6 weeks; jogging around 2-3 months; racquet sports around 3-6 months; skiing around 6+ months.[2]
- Overall results: In clinical studies, 96% of patients had meaningful pain relief at 2 years, and 85% had not progressed to a total knee replacement after 5 years.[1][2]
Every recovery is different. Dr. Thon will walk you through your personal timeline in detail.
Why Choose Orchard Orthopedics for This
You'll always see Dr. Thon personally for your initial evaluation, not a resident or rotating provider. Dr. Thon is one of only a handful of surgeons in Colorado certified to perform the MISHA procedure, and is focused on preserving your natural knee for as long as possible, offering it as a genuine alternative for patients caught in the gap between “not ready for replacement” and “out of non-surgical options.” And when a replacement really is the right answer, he'll tell you honestly, rather than delaying care he doesn't personally provide, paired with the direct access and unhurried follow-up care Orchard Orthopedics is built around.
Patient Story
Build as a sliding/rotating testimonial widget, same carousel pattern as other pages.
Real patient experiences with the MISHA Implant from around the country.
“I'm doing things I haven't been able to do for 15 or 20 years.”
— Chuck, three years after MISHA surgery (age 58 at time of surgery)“It's been about five and a half years now, and I still feel great, my activity's not limited, my knee feels good. This doesn't cure OA, it treats the symptoms, and it does it enormously effectively for me.”
— Zach, over five years after MISHA surgery (age 33 at time of surgery)“This was the thing I needed. This was what I was looking for, and I didn't know it.”
— Miranda, over five years after MISHA surgery (age 22 at time of surgery)“By noon, it was all done. I was home and laying on the couch with my knee elevated by afternoon.”
— Karla, over five years after MISHA surgery (age 58 at time of surgery)Frequently Asked Questions
Understanding Your Condition
Not always, and not right away. Many patients get real relief from physical therapy, weight management, medication, or injections. Dr. Thon will tell you honestly when those options are still likely to help.
Arthritis tends to progress over time. Left untreated, pain and stiffness typically worsen, and your options may narrow as the joint deteriorates further. An evaluation gives you an honest picture of where you stand.
Deciding on Treatment
No. Dr. Thon's focus is on preserving your natural knee for as long as possible through non-surgical care and joint-preserving options like the MISHA Implant. If and when a full replacement is genuinely the right next step for you, he'll tell you honestly and refer you to a trusted colleague for that procedure.
MISHA is generally intended for patients with early-to-moderate osteoarthritis on the inner side of the knee, or bone-on-bone arthritis limited to that same area, who've failed conservative treatment but aren't ready for, or don't want, a full knee replacement. It's not suitable for arthritis affecting the entire knee, inflammatory arthritis, active infection, poor bone quality, poor alignment, or a BMI over 40. Dr. Thon will evaluate your imaging and symptoms to tell you honestly whether you're a good fit.
Arthroscopy can help with mechanical symptoms like catching or locking, but it doesn't treat arthritis itself, and outcomes are inconsistent when arthritis is the main source of pain. Dr. Thon will tell you honestly whether arthroscopy is likely to help your specific case, or whether it's likely to fall short.
MISHA doesn't remove any bone or cartilage and is placed outside your knee joint capsule, acting as an external shock absorber rather than replacing joint surfaces. That means it preserves your future surgical options, including a total knee replacement later, if you ever need one, and comes with a far less invasive recovery.
Yes. If your bone-on-bone arthritis is limited to the medial side of your knee, you can still be a candidate for MISHA. Most patients still see significant relief, though those with more advanced, bone-on-bone arthritis generally see less relief than patients with milder, earlier-stage arthritis. Dr. Thon will give you an honest sense of what to expect based on your specific case.
In clinical studies, about 14% of patients had their device removed within 2 years, and 90% of those patients continued to experience benefit even after removal. Removing the device doesn't close off other treatment options, including knee replacement, down the road.
Yes, especially before any procedure. A second opinion isn't a lack of trust in your first doctor. It's a normal, expected step, and many patients return to their original surgeon with more confidence in the plan either way.
I have no insurance panel dictating my decisions and no quota to hit. I'll tell you honestly when non-surgical care is still realistic for your knee, and when it's time to consider MISHA or a referral for replacement.
That's a completely normal reaction. Your visit is the place to ask every question you have, including ones about anesthesia, risk, and what the day of the procedure actually looks like, until you feel genuinely informed, not just signed up.
Access & the Orchard Model
No. You can call and schedule directly, no referral or prior authorization required.
You'll always start with Dr. Thon on your initial visit. He remains closely involved in your care throughout, including alongside our PAs.
Surgery & Recovery Logistics
Most patients can be seen same-day or next-day. Call the office and we'll get you scheduled quickly.
Typically 2-3 hours, though plan to be at the surgical facility for 4-5 hours total. It's an outpatient procedure, so you'll go home the same day.
Yes, you may be able to feel it along the inner side of your knee. This is normal and typically not painful, though a direct hit to the area can feel similar to hitting your funny bone.
Most people return to driving within 2-6 weeks, once fully off narcotic pain medication. If your surgery is on your right knee, expect it to take a bit longer to get back to driving than if it's your left. Return to work depends on your job: desk work is often possible within 2-3 weeks, while heavy labor may take 8 or more weeks.
Most patients see rapid, substantial improvement early on, with full recovery for most activities generally within 3-6 months, and a full return to higher-impact activities like skiing around 6 months or more.
A knee replacement may not be your only option, find out with an honest conversation.
Already have a diagnosis or imaging from somewhere else? [ Get a second opinion ]
References
[1] Dr. Thon's MISHA Knee Implant page (stephenthonmd.com).
[2] MISHA Knee Recovery Guide, Dr. Stephen Thon's practice.
[3] MISHA Knee System Rehabilitation Guidelines, Ohio State University / Moximed.
[4] MISHA Knee System Patient Brochure, Moximed.
[5] Treatment Guide: Knee Osteoarthritis with Meniscus Tear, Dr. Stephen Thon.