Chronic Knee Pain and Knee Instability

Ross Hauser, MD, Daniel

If you have come across this article you are probably searching for some type of answers that you are currently not finding to help you not only understand your knee pain, but to discover things that you can do about it. These would be treatments or remedies beyond your self-managed care of anti-inflammatories, knee braces, possibly physical therapy and the recommendation for an knee arthroscopic surgery or eventually a knee replacement. Or what you can do for your knee following your arthroscopic or keyhole surgery that did not help your problem and unfortunately made it worse.

In fact, if your were to search the internet archives of the most recent medical research on knee instability, most of the research will discuss the problems of knee instability following either an arthroscopic repir or a total knee replacement.

You may be reading this article today because today your knee pain is pretty bad or you were walking down a flight of stairs and your knee gave way or it took you a minute to get out of a chair while you gathered enough momentum to stand up. Your stand up routine includes desks, tables or laundry baskets properly placed for you to grab onto once you did stand up so that you would not have to plop back down in the chair or bed because your knee could not support you this time.

In this article we will discuss the degenerative knee disease process that leads to knee instability. We will spend some time talking about the knee ligaments. As you will see in the research and clinical case histories below. The knee ligaments are often the most over looked, unless you have a ACL or other ligament rupture, component of knee instability. You probably, as you have researched your knee problem, may have started to understand that your bone on bone, “no cartilage,” meniscus thinning, knee swelling and “my knee gives way” problems have a cause that few or your doctors talk to you about. That cause is ligament laxity.

Knee instability symptoms or knee ligament laxity symptoms

What you probably do not need is a list of symptoms describing your knee pain and knee instability. You have your own list developed over years of knee pain. But what if we changed knee instability symptoms into knee laxity symptoms.

So here is a list of knee ligament laxity symptoms:

  • Your knee gives way
  • Your knee catches or locks
  • Your knees are always puffy
  • Your knees bend in VALGUS or turn out VARUS (bow-legged)
  • Your doctors has made a recommendation for knee replacement.

Knee instability treatments

The standard therapeutic approaches for chronic knee pain include, but are not limited to, nonsteroidal anti-inflammatory drugs (NSAIDs), cortisone injections, hyaluronic acid injections, physical therapy, therapeutic exercise, arthroscopic surgery, partial or complete meniscectomy, and total knee replacement. Although these modalities may offer short-term pain relief, they often do not address the underlying problem of joint instability related to ligament, tendon, and meniscal injuries. Furthermore, these approaches tend to inhibit soft tissue healing and accelerate the degenerative process, rather than stimulate soft tissue repair. Pharmaceutical drugs like NSAIDs decrease these inflammatory substances, but their effect is temporary; they do not address the problem at the source – ligament injury and joint instability. The only curative treatment to stop the inflammatory substances is to restore normal joint stability.

Surgical intervention is prudent and necessary for traumatic knee injuries, such as fractures and complete ruptures of major ligaments, but may not be the best treatment for less severe injuries or for knee conditions in their early stage of development. Although there are conservative treatments in use for knee pain and knee joint dysfunction, many of them provide only short-term relief and have no proven long-term benefit; in some cases, significant adverse effects have been identified.

Everything in the knee affects the ligaments and the ligaments affect everything in the knee

Knee pain can start from a traumatic event, such as a fall or football tackle. Or it can become more apparent over time, with increasingly stiff and swollen knees. The underlying cause of knee pain is joint instability due to weakness in the ligaments and tendons surrounding the knee joint. Knee joint instability can also result in the knee cap tracking abnormally, causing pain and the cartilage under the knee cap to wear down. Surgical intervention to remove tissues, including the meniscus or cartilage, puts increased pressure on the other areas of the knee and worsens knee instability. Over time, this worsened joint instability leads to severe cartilage defects, osteoarthritis, and additional surgeries that will eventually include joint replacement. Ligaments function primarily to maintain smooth joint motion, restrain excessive joint displacement, and provide stability across the knee joint.

The ligaments of the knee provide:

  • Passive stability,
  • guide the motion of the femur and tibia,
  • define contact mechanics between the femur and tibia,
  • and restrain excessive motion to prevent dislocation.

When the forces to which ligaments are subjected are too great (acute injury or degenerative failure caused by ligament laxity), failure occurs, resulting in drastic changes in the structure and physiology of the joint.

What are we seeing in this image? This is how ligament laxity squeezes your meniscus out of your knee joint.

In the caption below are MRI like sounding terms so let’s make it a little simpler to understand what its is that we are seeing in this image.

  • This is an ultrasound image showing a meniscus being squeezed out of place or extruded. Extrusion is the way tooth paste comes out of a tube. For the tooth paste to come out there needs to be an unnatural pressure or an extra force exerted on the tube. That force is of course you squeezing the tube to make the tooth paste come out. Here the knee is being squeezed and the meniscus is being pushed out by valgus stress. What causes valgus stress? One answer is damage or weakness of the medial collateral ligament (MCL) of the knee. Ligamentous.

When your knee is fit and strong, it is stable. When it is worn and weak it is unstable.

A heavily referred to and cited British study published in the The Western journal of medicine, (1) suggests that stability of the knee joint is maintained by:

  • the proper shape of the condyles (the boney structures of the knee joint),
  • and the bones structural relationship with the meniscus, cartilage, and ligaments of the knee.

This too sounds obvious, however the core message is that stability of the knee joint is maintained by the entire knee working in concert, AND, this concept is easily lost during a physical examination by doctors who see a torn meniscus and want to operate without realizing the damage surgery can cause the articular cartilage, bone, and ligaments the removal of the meniscus can cause. This particular problem is discussed at length in our article on meniscus repair without surgery.

Ligament Mechanical Laxity explored further

  • Mechanical laxity refers to an excess in the range of motion in the knee due to loss of integrity of the ligaments and other soft tissues which contribute to joint stability.
  • Functional instability refers to a sense of instability or giving out of the joint experienced in the course of daily activities or strenuous exercise. It is possible to have functional knee instability from muscle weakness alone; thus functional instability may or may not be associated with mechanical laxity.

The four major ligaments of the knee are:

The medial collateral ligament and  posterior cruciate ligament are attached to the medial condyle, the lateral collateral ligament is attached to the lateral condyles.

Now we have ligaments that are compromised by the bone degeneration and begin to loose their characteristic tautness because their bone attachments are degenerating.

Conversely, working backwards in a different patient scenario, it is instability in these ligaments that may have started the degenerative cascade of the condyles and menisci. Wear and tear, past impact injuries, everything in the knee affects the ligaments and the ligaments affect everything in the knee.

What are we seeing in this image? Knee instability

In the image below are four terms. Here is what they mean to you as they describe the elements of knee pain and instability. To see that these instabilities are problems regularly discussed in the medical community, lets look at and summarize and explain findings in a 2019 paper published in the Journal of experimental orthopaedics (2) and led by the University of Pittsburg.

The four terms are:

  • Anteromedial instability
  • Posteromedial instability
  • Anterolateral instability
  • Posterolateral instability

Anteromedial instability

Anteromedial rotatory instability results from excessive valgus strain with simultaneous external rotation of the knee, (in other words your knee is rotating outward, beyond your knee cap pointing excessively outwards are your toes pointing the same way.)

This can lead to pathologic anterior subluxation of the medial tibial plateau relative to the medial femoral condyle. (The tops of your shin bones at the knee are moving forward (subluxation) away from their natural placement under the bottom of the thigh bone (the medial femoral condyle). Anteromedial rotatory instability can be caused by injury to the superficial and deep medial collateral ligaments, posterior capsule, and posterior medial corner (PMC).

Posteromedial instability

Posterolateral Rotatory Instability involves injury to the arcuate ligament complex, comprised of the lateral collateral ligament (LCL), arcuate ligament, popliteus muscle and tendon, and lateral head of the gastrocnemius. Posterolateral Rotatory Instability usually is the result of a hyperextension, varus moment, and rotatory force on the knee. This causes the lateral tibial plateau to subluxate posteriorly in relation to the lateral femoral condyle.

In the Journal of Prolotherapy, I describe a case history of arcuate ligament injury:

While most physicians and lay people know terms such as the anterior cruciate and posterior cruciate signify ligaments of the knee, most are not as familiar with the term arcuate ligament. The arcuate ligament is a Y-shaped structure that lies just behind the lateral collateral ligament and along with it, provides posterolateral stability to the knee.

Any injury or trauma to the lateral side of the knee is likely to injure the posterolateral knee structures. This can occur with a direct blow to a flexed knee while the tibia is externally rotated or a blow to an extended knee with the tibia internally rotated. Rarely is the arcuate ligament injured just by itself. When cruciate ligaments are also injured, typically these are addressed first. In fact, clinically unrecognized posterolateral injury has been suggested as a cause of post-surgical cruciate ligament failure or chronic instability of the knee.

In our case history the patient injured her right knee by stepping over a door threshold. She felt her knee go out with pain in the posterior knee. She went to several doctors and was prescribed anti-inflammatories and told to ice the area, which did not offer pain relief. X-rays of her knee were normal. Her prior diagnoses included exacerbation of osteoarthritis, tendonitis of the knee and “strain.” Even six weeks of physical therapy did not help and the patient noted that it may have made her feel worse. An orthopedic surgeon ordered an MRI of her knee which came back as normal. He administered a cortisone shot which helped for a few weeks, but then the pain came back.

Six month after her original injury and after these unsuccessful therapies, the patient came to Caring Medical. She stated that prior to coming to Caring Medical, nobody even examined the back side of her knee. She maintained her primary problem was on the posterior and lateral side of the knee. Besides exhibiting severe tenderness to palpation on the posterior fibular head, she also exhibited a positive posterolateral drawer test. No external rotation recurvatum was present. JH was treated with Prolotherapy to her arcuate ligament complex. She received a total of three monthly treatments to resolve her pain. Before Prolotherapy, her activity was limited to just walking, whereas now she has no limits, as evidenced by a recent pain-free hike up and down several miles of hilly terrain.

Knee ligament instability – the cause of meniscus and cartilage wear and tear and bone on bone

Sports medicine doctors in Europe, writing in the journal Knee surgery, sports traumatology, arthroscopy suggest that when dealing with knee instability in patients doctors should be wary that “the interpretation of multidirectional knee laxity (the knee overextends in multiple directions) is complex and suggests the necessity for individualized care of knee diseases and injuries.”(3)

  • What these researchers are saying is let’s get a good physical examination and look at the knee. Please see my article Is My MRI Accurate? This includes looking for ligament laxity.

But going a little further look at what the study suggests:

“Physiological knee laxity has received little attention in spite of indications that it influences knee diseases/injuries and their outcomes. Excessive laxity has been recognized as a risk factor for non-contact ACL injuries and more importantly for worse ACL reconstruction outcomes.” (Please see my article After ACL Reconstruction | Complications and knee instability)

“Our findings may therefore stimulate the debate around the need for individualized care of knee injuries and disease. More work is needed to improve the comprehension of the role of individual knee function in the occurrence of degenerative knee diseases, knee injuries (e.g. non-contact ACL injuries) and poor treatment outcomes.”

  • The reason for poor outcomes, knee instability is not understood.

Being weak in the knees. Why does your knee buckle? Are you a fall risk?

For patients who are being managed until knee replacement, or are putting off any treatment to fix his/her knee, there is the problem of knee buckling. Knee buckling is the knee giving out. Most times people will be able to grab unto something or someone close by to prevent a fall. If not, there can be a fall. People with knee osteoarthritis and knee instability are a fall risk.

Why does your knee buckle? Simply the knee at that moment cannot support your weight, your knee is collapsing under your weight.

The story of “wear and tear.”

In an April 2017 study published in the medical journal Cartilage, (4) doctors in Japan made the obvious but often overlooked observation about knee instability.

  • Osteoarthritis is the result of knee instability or using a more medical term “accumulated abnormal mechanical stress” or  simply “abnormal joint movement of the knee.” (In common language this means “wear and tear.”)
  • Abnormal joint movement of the knee (knee instability) causes wear and tear osteophyte (bone spur) formation;
  • Abnormal joint movement of the knee (knee instability) causes wear and tear knee cartilage breakdown;
  • Therefore, treating abnormal joint movement of the knee (knee instability) may be a beneficial precautionary measure for osteoarthritis progression in the future.Preventing continuation of wear and tear.

This same research team in February 2017 wrote in the journal Osteoarthritis and cartilage: discussing instability from ACL wrote:

Re-stabilization of (knee) instability may suppress inflammatory cytokines (chronic inflammation), thereby delaying the progression of osteoarthritis. (Knee) instability is a substantial contributor to cartilage degeneration.(5) In other words aggressive wear and tear.

The core message is that stability of the knee joint is maintained by the entire knee working in concert. Instability is also a factor of the entire knee and not simply one damaged component.

The knee condyles (medial for the middle and lateral for the outside) are bony structures that sit in the bottom of the thigh bone in the knee joint that assist in keeping the knee from hyperextending (bending too far.) The medial condyle is larger bone structure because it bears more weight. As we age, and a lifetime’s stress impact our knees, these bones wear away. Their degeneration has been clearly associated with meniscus degeneration.

The meniscus is the cartilage padding that acts as a shock absorber. When it is damaged, the protective articular cartilage that covers the thigh and shin bones are now stressed because it is assuming the mechanical load normally taken care of by the meniscus.. What we have here is the beginnings of bone-on-bone knee.

The above process is a multi-fold attack on knee stability.

  • First the boney structure that prevents excessive movement wear away causing excessive or hypermobile movement.
  • That hypermobility as well as surface pressure (impact loads of our body weight on our knees) cause meniscus damage, the meniscus damage causes articular cartilage damage.

So the simple understanding is – knee stability is maintained by the the shape of the condyles and menisci, and knee instability occurs when these structures suffer degenerative wear and tear or osteoarthritis.

More research: The following studies demonstrate how important the ligaments are to the stability of the knee

In the first study, a classic 1993 paper published in the American Journal of Sports Medicine,  concerning posterior cruciate ligament laxity, the researchers note:

  • Knees with underlying physiologic cruciate ligament laxity had the greatest lateral tibial plateau subluxation.” In other words when the ligaments were compromised the knee became misaligned – displaced. (6)

The second study, another classic study lead by the same research team leader, Dr. Frank R. Noyes,  on anterior cruciate ligament laxity states, “After anterior cruciate sectioning alone, both the lateral and medial tibial condyles displaced (subluxed) anteriorly.”(7)

In other words a partial tear of the ACL resulted the condyles being displaced. See above the medial collateral ligament and posterior cruciate ligament are attached to the medial condyle, the lateral collateral ligament is attached to the lateral condyles.

And again concerning the ACL, the third research team reports, “Significant increases in internal rotation occurred in seven knees when only the anterior cruciate ligament had a partial tear.(8)

Pes anserinus tendons

A common cause of chronic knee pain is weakness in the pes anserinus tendons. Below the knee cap, on the inside of the knee, are the attachments of three tendons: semimembranous, semitendinosus,  and gracilis. Together, these tendons create the pes anserinus area.

When left untreated, may contribute to developing arthritis. Even in cases of significant arthritis, crippling knee pain is often due to pes anserinus tendonitis or bursitis. This condition is easily treated with Prolotherapy, eliminating the chronic knee pain. The pes anserinus tendons are also known as the inside hamstring muscles. Most of us have very weak hamstring muscles that are short because we sit for a large portion of our day.

The pes anserinus tendons flex the knee and stabilize the inside of the knee. Patients with fallen arches are prone to strains in these muscles. The tibia tends to rotate outward to compensate for the fallen arch. Running, hiking, pregnancy, and aging may predispose a patient to develop a fallen arch. This outward rotation of the tibia places additional stress on the pes anserinus tendons. Eventually, these tendons become lax and are no longer able to control the tibial movement, adding to the chronic knee pain. Addressing the fallen arches of the foot may also be required to fully alleviate the knee pain. Prolotherapy injections strengthen the tendon attachments of the pes anserinus, resolving the chronic knee pain.

Comprehensive Prolotherapy for problems of knee instability and wear and tear and bone on bone

Comprehensive Prolotherapy used in some cases with Platelet Rich Plasma Therapy and Stem Cells works at the root of the problem, the ligament or soft tissue damage. A series of injections are placed at the tender and weakened areas of the affected structures of the knee. These injections contain a proliferant to stimulate the body to repair and heal by inducing a mild inflammatory reaction. The body heals by inflammation, and Prolotherapy stimulates this healing. The localized inflammation causes healing cells to arrive at the injured area and lay down new tissue, creating stronger ligaments and rebuilding soft tissue. As the ligaments tighten and the soft tissues heal, the knee structures function normally rather than subluxing and moving out of place. When the knee functions normally, the pain goes away.

In published research in the Journal of Prolotherapy, we investigated the outcomes of patients receiving Prolotherapy treatment for unresolved, difficult to treat knee pain at a charity clinic in Illinois. Here are the bullet points of our research:

  • The results of this retrospective, uncontrolled, observational study, show that Prolotherapy helps decrease pain and improve the quality of life of patients with unresolved knee pain.
  • Decreases in pain, stiffness, and crunching levels reached statistical significance with Prolotherapy.
  • The percentage of patients with less knee pain was 95%, and 99% reported long term improvements in stiffness after Prolotherapy.
  • Eighty-six percent of patients decreased their need for additional pain therapies, including medication usage by 90% or more, after Prolotherapy.
  • Eighty-two percent showed an improvement in sleep.
  • For those with depression and anxiety, 86% were less depressed and 82% were less anxious.
  • In regard to activities of daily living, Prolotherapy improved walking ability in 84%, athletic ability in 76%, and dependency on another person in 75% of patients treated.
  • Of the patients treated with the Hackett-Hemwall technique of dextrose Prolotherapy, 95% felt an overall improvement in their quality of life.
  • Ninety-four percent of patients noted their improvement in overall disability has mostly continued since their last treatment.

The key to curing chronic knee pain is locating the points within the knee that are the cause of knee instability. Healing from knee pain necessitates finding the source of the knee pain, while knowing and understanding the correct diagnosis. Too often, the correct diagnosis of knee instability is missing. Once the instability is found, then a program of Prolotherapy injections should be able to repair the damage and stabilize the joint.

Patients who come to Caring Medical are generally well educated on their condition. Of these, about half know the exact location of their knee instability and its cause; the other half do not. Even my fellow Prolotherapists do not always recognize whole joint knee instability, in that approximately 10% of new patients we see have already received Prolotherapy from someone else, but have had little resolution of their symptoms.

One of these patients had several scans, including an ultrasound and MRI, which showed patellar tendinosis, and had subsequently received 20 sessions of minimal Prolotherapy and platelet rich plasma (PRP) injections to the patellar tendon, but to no avail. Why was she still in pain?

She had knee joint instability that was putting increased pressure on her patellar tendon, causing its breakdown. The instability was evident on physical examination, showing that almost all of her ligaments were stretched out. We used Comprehensive Prolotherapy which treats the whole joint, including the ligaments, and after three sessions she was running and playing tennis again!

In simple terms, the ligaments, tendons, synovial tissue, cartilage, meniscus, etc., that hold your knee in proper anatomical alignment have been weakened by degenerative disease caused by wear and tear, acute injury, or poor lifestyle choices such as obesity and inactivity.

Treating the whole knee treats widespread body pain

If there is any more doubt that knee pain is  guiding force in disruption of the body homeostasis (the balance between health and non-health) and a cause of why your whole body hurts when you have knee pain. Listen to this research:

Seven Universities, the University of Montreal, Kansas, Alabama, California at Davis UCD, California at San Francisco UCSF, Iowa, and the Boston University School of Medicine teamed up to present findings in the medical journal Arthritis care & research that suggests knee osteoarthritis causes wide spread body pain.

The research team looked at patients who had or were at risk of knee osteoarthritis. These were patients who had consistent frequent knee pain, radiographic documented osteoarthritis, symptomatic osteoarthritis, and knee pain severity at the 60-month visit (baseline).

  • Widespread pain was categorized as:
    • pain above and below the waist,
    • on both sides of the body and axially.
  • Incident widespread pain was defined as the presence of widespread pain at 84 months in those who were free of widespread pain at baseline.

Consistent frequent knee pain, symptomatic knee osteoarthritis, and knee pain severity increased the risk of developing widespread body pain, independently of structural pathology. Meaning the severity of the damage to the diseased knee was not the factor, but the level of pain the patient was experiencing was.1

Side note: Over the years we have seen patients who had terrible Knee MRIs showing incredible damage, but for the most part they had no pain. We have also seen patients who had little damage, who had very much pain. What the study suggests is you must help the patient find the cause of the pain, and sometimes it is not in the structural damage.

Prolotherapy helps strengthen chronically weak and damaged knee ligaments and can help alleviate the patient’s symptoms of pain, function and instability. If the area is appropriately treated with Prolotherapy, not only is the chronic pain eliminated, but the joint instability is corrected.

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