Injections for the different types of meniscus tears

Ross A. Hauser, MD., Danielle R. Steilen-Matias, MMS, PA-C

Non-surgical repair of the different types of meniscus tears

If you are reading this article you have likely been diagnosed with a meniscus tear and have just had, or are waiting for an MRI to determine the extent of your knee damage. Depending on your MRI results you will be offered one of three choices:

Do nothing.
Do something non-surgically.
Get surgery.

The reason you are probably reading this article is that you are exploring all these options and are probably leaning towards finding another way besides surgery. In this article you are going to see a lot of research, the orthopedists will speak up, the physical therapists are going to speak up, and the regenerative therapist, health care providers offering regenerative medicine injections, that would be us, is going to speak up. So let’s look at the different types of meniscus tears and what you can do non-surgically to treat them.

We are going to present a brief video that explains the concept of knee instability and how it impacts your pain and function in a meniscus-damaged knee.

A brief video on knee instability and a bulging meniscus – the many types of meniscus tears may have ligament damage as a common factor

In this video, knee instability is easily documented by stressing the knee (bending it and flexing it) and observing the knee’s function and motion under ultrasound examination. Ultrasound is a real-time, motion-based image that differs from static MRI images where a snapshot is taken of the knee in various static poses.
(At 0:15 of the video) In a BEFORE ultrasound, here the meniscus can be seen bulging in and out of the knee because of excessive motion from ligament laxity and injury. In other words, the meniscus is moving in and out of its proper place in the knee joint because the supportive knee ligaments that help hold the meniscus in place are damaged. The whole knee is unstable.
In the AFTER ultrasound and after Prolotherapy injections, (which is how this patient was treated, the treatment is explained below) the ligaments were strengthened and tightened. The meniscus is now is in its proper alignment and no longer subject to degenerative contact stress.

Non-Surgical treatment options for the different types of Meniscus tears

A December 2021 paper published in the Journal of experimental orthopaedics (1) revealed the thoughts of the attending members of the 2021 5th International Conference on Meniscus Science and Surgery in “for furthering the state of meniscus science in 2021.”

The most important findings of this survey were that the highest ranked future research and development focus areas should include meniscus repair, biologics, osteotomy procedures, addressing meniscus extrusion (your meniscus is sticking out beyond the shin bone and has its causes in root tear), and the development of new therapies for the prevention of Post-traumatic osteoarthritis. Currently, the reported most ‘valuable’ type of biologic for meniscus treatment was PRP, while amniotic fluid was reported as least ‘valuable’.

So what are we reading here? The doctors thought that the feature of meniscus tear treatment should be on:

Repairing not removing meniscus tissue
Biologics. This is sometimes referred to as “cellular” treatments or “platelet” treatments./ More commonly Platelet rich Plasma therapy and Stem Cell Therapy.

Red zone tear, white zone tear. When non-surgical options can work and when surgery will be the “only” choice

We are now going to expand on our discussion of the White Zone Tear, the Red Zone Tear, and the tear that goes across the red zone and the white zone.

Menisci have two zones. The red zone is the meniscus’ outside zone the white zone is the inside zone. Meniscus tears are characterized by their placement within these two zones. In your many doctor visits, you probably received a pretty good education in what red zone tears and white zone tears are of the menisci.

A red zone tear lies within the blood-rich portion of the meniscus. Where there is a blood supply there is healing as blood brings the healing and growth factors needed for wound repair.

The white zone meniscal tear is thought to be non-healing because there is no direct blood supply.
Many doctors do not believe the white zone meniscus tear can be repaired because of this.
This is typically the part of the meniscus removed in meniscus surgery.

What are we seeing in this image?

If you have a red zone tear, there is a chance arthroscopic surgery can go in and sew it up. If you have a white zone tear, it is most likely that your meniscus will be removed. All or some of it. The great majority of meniscus arthroscopic surgeries are to REMOVE meniscus tissue. In this image, we note that the meniscus has a poor healing ability because approximately 70% of the meniscus gets no direct blood supply. This is why the meniscus has a white zone. In the other 30% of the meniscus that gets a blood supply, this creates the “red zone.”

If you have a red zone tear, there is a chance arthroscopic surgery can go in and sew it up. If you have a white zone tear, it is most likely that your meniscus will be removed. That would be all or some of it. The great majority of meniscus arthroscopic surgeries are to REMOVE some amount of meniscus tissue.

Partial-thickness tears or full-thickness tears: The other classification of the meniscus tear is related to the depth of the tear.

What are we seeing in this image?

Meniscus tears can be considered to either be partial-thickness tears or full-thickness tears. Partial-thickness tears are tears that only extend partway across the meniscus, while full-thickness tears extend fully across. So, if you have a full-thickness flap tear, then it is a tear that cuts across the meniscus completely.

No matter the tear, partial meniscectomy and physical therapy may not work or may work. It is hard to tell.

Above we cited a study from a group of physical therapists discussing how their patients perceived arthroscopic surgery and their (the patients) relative disappointment that they did not get surgery. The physical therapists wrote that these people need to be educated on the reality of the success of arthroscopic knee surgery.

This is a study from orthopedic surgeons writing in the medical journal Arthroscopy. (12) If ever there were to be a favorable study on the surgery you would think this was it. Not so. In this study, doctors suggest that there is currently no compelling evidence to support arthroscopic partial meniscectomy versus physical therapy. The studies evaluated in this research are not robust enough at this time to support claims of superiority for either alternative, and both arthroscopic partial meniscectomy or physical therapy could be considered reasonable treatment options for this condition.

They may work, one may or may not work better than the other. The research is not sure.

Two studies – seven years apart 2013 – 2020

We are going to look at two studies on physical therapy, surgical avoidance, and meniscus tears. Both lead by Jeffrey N. Katz, MD. The first study, considered by many a landmark study, was published in the New England Journal of Medicine. (13)

Here the research team studied 351 patients with either a torn meniscus or knee osteoarthritis for 12 months.
They randomly assigned the patients to either a physical therapy group or an arthroscopic surgery group.
They evaluated each patient’s pain and knee function at six and 12 months and discovered that after one year the results were about the same: both had some improvement with no significant difference between the two treatment options.
The one interesting fact is that patients had the option to crossover into the other treatment group. 51 patients in the physical therapy group decided to go ahead with surgery, whereas only 9 patients in the surgery group chose to switch to physical therapy. No reasons were given as to why the patients decided to switch.

Did the physical therapy group or the surgery group have more pain or less pain 5 years down the road?

Is successful meniscus surgery a matter of luck? Do you have the same chance for a successful outcome if you just rehab with exercise?

This is a March 2020 study published in the British Journal of Sports Medicine (15). What this study wanted to do was examine the ability of surgeons to predict the outcome of treatment for meniscal tears by arthroscopic partial meniscectomy and exercise therapy in middle-aged patients.

Here is how the study worked:

A group of orthopedic surgeons was given 20 patient profiles to examine. These profiles were derived from a randomized clinical trial comparing arthroscopic partial meniscectomy with exercise therapy in middle-aged patients with symptomatic (painful) non-obstructive meniscal tears. From each treatment group (arthroscopic partial meniscectomy and exercise therapy), the researchers selected five patients with the best and five patients with the worst knee function after treatment.

The surgeons of this study make a recommendation for treatment. Was surgery correct?

Next, the surgeons (unaware of what treatment the 20 patient profiles they were looking at had, surgery or exercise) had to choose between arthroscopic partial meniscectomy and exercise therapy as preferred treatment and subsequently had to estimate the expected change in knee function for both treatments. Finally, surgeons were asked which patient characteristics affected their treatment choice.

The point of this study is that the surgeons are looking at 20 patient profiles. The 20 people already had either surgery or exercise therapy. The results of how successful the surgery was and how successful the exercise therapy was, was used to determine if the surgeon made the “right call.”

Results: Surgeons making a successful meniscus surgery prediction and a coin toss. The chance was equal.

Typically when patients decide whether to have surgery or not they typically do not toss a coin. Probably some do because they do not have enough information to make a more educated assessment of their chances of having a successful surgery or having equal success with non-surgical options.

So here are the results of this study. Remember a surgeon was asked to look at 20 patient profiles and make a recommendation for surgery or no surgery. The 20 patients had already had surgery or exercise therapy and the successful results of their treatment had already been recorded. How did the surgeons do? They may as well have flipped a coin.

Here is what the study said:

Overall, 50.0% of the (surgeon’s) predictions were correct, which equals the proportion expected by chance.
Experienced knee surgeons were not better at predicting outcomes than other orthopaedic surgeons.
In general, bucket handle tears, knee locking, and failed non-operative treatment directed the surgeons’ choice towards arthroscopic partial meniscectomy, while a higher level of osteoarthritis, degenerative (problems), and the absence of locking complaints directed the surgeons’ choice towards exercise therapy.

Conclusions: Surgeons’ criteria for deciding that surgery was indicated did not pass the statistical examination. This was true regardless of a surgeon’s experience. These results suggest that non-surgical management is appropriate as first-line therapy in middle-aged patients with symptomatic non-obstructive meniscal tears.

In Comprehensive Prolotherapy, the knee joint instability is restored by repairing and regenerating tissue

We use non-surgical treatments for meniscus tears. We may use our Prolotherapy treatments and PRP. This is an in-office injection treatment. This video and the summary below is an introduction to our non-surgical treatments. It is presented by Danielle R. Steilen-Matias, MMS, PA-C.

Dextrose Prolotherapy is a simple sugar injection into the knee that attracts your own healing repair cells into the area to fix the damaged meniscus
In some patients, it may not be enough to attract your own cells to this damaged area with Prolotherapy, in this type of case we may have to put cells there via injection. Our first option would be Platelet Rich Plasma (PRP) Prolotherapy. This would put the healing factors found in your blood platelets into the damaged joint.
- WE DO NOT offer PRP as a stand-alone treatment or injection. While PRP brings healing cells into the joint, it acts to repair degenerative damage. In our experience, while PRP addresses damage deep in the such as a meniscus, we must still address the joint instability problem created around the knee. We do this with Prolotherapy. Here damaged or weakened ligaments that are simply “stretched,” can be strengthened with treatment to help restore and maintain normal joint mobility. We discuss the meniscus interaction with the MCL in a moment. Simple PRP on the inside, Prolotherapy on the outside of the joint.
- PRP is injected at the meniscus with ultrasound guidance
Most meniscal tears require four to six treatments although that could be less or more depending on the patient.
What helps our success rate with meniscal tears is our treatment of the MCL or the medial collateral ligament at the same time.
We will use of ultrasound machine to access the integrity of the MCL

Platelet Rich Plasma Therapy and Prolotherapy, which stimulates tendons, ligaments, and cartilage to heal, has many advantages over arthroscopy, which include:

These treatments are considered a much safer and conservative treatment
the procedure does not take long to administer; an individual is usually in and out of the doctor’s office in less than an hour
it stimulates the body to help repair the painful area; for example, the new collagen tissue formed is actually stronger than it was before the injury
it reduces the chance of long-term arthritis; with arthroscopy, the chance of long-term arthritis increases
in the case of athletes, it increases their chances of being able to play their sports for the rest of their lives; arthroscopy significantly decreases those chances
exercise is encouraged while getting Prolotherapy treatments; one must be very cautious with exercise after arthroscopy
the procedure is much less invasive; remember that arthroscopy requires the knee to be blown up with about 100 ml of fluid to fit all the scopes into the knee.

Many patients at this point, exploring non-surgical options will look into stem cell therapy.

The reality of stem cell therapy

Stem cell therapy can be an effective treatment for meniscus damage. We have seen excellent results in many patients. However, stem cell therapy needs to be understood within the reality of what this treatment can and cannot do and how this treatment should be used.

We don’t treat everyone with stem cell therapy

It is important to note that we do not use stem cell therapy on every patient. In fact, we use stem cell therapy in very few of our patients. We find that other simpler and less costly regenerative medicine injection treatments can work just as well. This is explained below.

If you do not have a meniscus, stem cell therapy as an injection will not make a new one

Over expectation of what stem cell therapy can do may lead to patient disappointment

In many people who reach out to our office, we find that they have an unrealistic expectation of what stem cell therapy can offer them. For some people, stem cell therapy cannot, in one simple injection, repair, and reverse years of degenerative damage. Many treatments may be necessary. Patients should be aware of what stem cell therapy can really do.
For example, stem cell therapy cannot generate a meniscus from nothing. If you do not have a meniscus, stem cell therapy as an injection will not make a new one. If you have a meniscus tear, lesion, or hole in cartilage, stem cell therapy may help create a natural healing patch, but, the treatment, like any medical treatment, has its limitations. Stem cell therapy can patch a hole, but without supportive treatments to address what caused the degenerative knee condition and what caused the hole in the cartilage in the first place, (knee instability and degenerative wear and tear motion from damaged and weakened knee ligaments), stem cell therapy will not be the single-shot cure a patient will hope for.

December 2021 the research on stem cell therapy for treating a meniscus

Here is a summary viewpoint of the current state of stem cell repair of a meniscus tear published in December 2021 in the journal Orthopaedic surgery.(10) According to the authors: “”Due to the special anatomical features of the meniscus, conservative or surgical treatment can hardly achieve complete physiological and histological repair. As a new method, stem cells promote meniscus regeneration in preclinical research and human preliminary research. We expect that, in the near future, in vivo injection of stem cells to promote meniscus repair can be used as a new treatment model in clinical treatment. The treatment of animal meniscus injury, and the clinical trial of human meniscus injury has begun preliminary exploration. As for the animal experiments, most models of meniscus injury are too simple, which can hardly simulate the complexity of actual meniscal tears, and since the follow-up often lasts for only 4-12 weeks, long-term results could not be observed. Lastly, animal models failed to simulate the actual stress environment faced by the meniscus, so it needs to be further studied if regenerated meniscus has similar anti-stress or anti-twist features.”

Still a great potential to repair

Despite these limitations, repair of the meniscus by MSCs has great potential in clinics. MSCs can differentiate into fibrous chondrocytes, which can possibly repair the meniscus and provide a new strategy for repairing meniscus injury.

If you are exploring stem cell therapy for a meniscus tear, the great likelihood that you are doing this research is that you are looking for an option for surgery. Please see our article Does stem cell therapy for knee meniscus tears and post-meniscectomy work?

Summary and contact us. Can we help you?

We hope you found this article informative and it helped answer many of the questions you may have surrounding your knee problems and knee instability. If you would like to get more information specific to your challenges please email us: Get help and information from our Caring Medical staff

Brian Hutcheson, DC | Ross Hauser, MD | Danielle Steilen-Matias, PA-C

Subscribe to our newsletter

8 Urzen JM, Fullerton BD. Nonsurgical Resolution of a Bucket Handle Meniscal Tear: A Case Report. PM R2016 Jun 6. pii: S1934-1482(16)30158-7. [Google Scholar]
9 Stender ZC, Cracchiolo AM, Walsh MP, Patterson DP, Wilusz MJ, Lemos SE. Radial Tears of the Lateral Meniscus—Two Novel Repair Techniques: A Biomechanical Study. Orthopaedic journal of sports medicine. 2018 Apr 27;6(4):2325967118768086. [Google Scholar]
10 Atik OŞ. Should degenerative horizontal tear of the medial meniscus be treated with surgery?. Eklem hastaliklari ve cerrahisi= Joint diseases & related surgery. 2018 Aug;29(2):63-4. [Google Scholar]
11 Hohmann E, Glatt V, Tetsworth K, Cote M. Arthroscopic partial meniscectomy versus physical therapy for degenerative meniscus lesions: How robust is the current evidence? A critical systematic review and qualitative synthesis. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2018 Jul 20. [Google Scholar]
12 Katz JN, Brophy RH, Chaisson CE, De Chaves L, Cole BJ, Dahm DL, Donnell-Fink LA, Guermazi A, Haas AK, Jones MH, Levy BA. Surgery versus physical therapy for a meniscal tear and osteoarthritis. New England Journal of Medicine. 2013 May 2;368(18):1675-84. [Google Scholar]
13 Katz JN, Shrestha S, Losina E, Jones MH, Marx RG, Mandl LA, Levy BA, MacFarlane LA, Spindler KP, Silva GS, MeTeOR Investigators. Five‐Year Outcome of Operative and Nonoperative Management of Meniscal Tear in Persons Older Than Forty‐Five Years. Arthritis & Rheumatology. 2020 Feb;72(2):273-81. [Google Scholar]
14 van de Graaf VA, Bloembergen CH, Willigenburg NW, Noorduyn JC, Saris DB, Harris IA, Poolman RW. Can even experienced orthopaedic surgeons predict who will benefit from surgery when patients present with degenerative meniscal tears? A survey of 194 orthopaedic surgeons who made 3880 predictions. British journal of sports medicine. 2020 Mar 1;54(6):354-9. [Google Scholar]
18 Dai TY, Pan ZY, Yin F. In Vivo Studies of Mesenchymal Stem Cells in the Treatment of Meniscus Injury. Orthopaedic Surgery. 2021 Nov 8.

This article was updated July 11, 2021

3252