Chronic pain after knee replacement

Ross Hauser, MD

Can we help you with continued knee pain after knee replacement surgery? In this article we will address post-surgical problems that can be successfully treated with comprehensive Prolotherapy.

Comprehensive Prolotherapy helps in providing knee stability by strengthening connective structures such as ligaments and tendons.

If you have questions about knee replacement options, contact us for help and more information

The debate over whether or not to have a knee replacement is not a new on. Back in 2006, the rate of knee replacement failures caused some concern that maybe everyone is NOT a candidate for knee replacement.

  • Findings at that time published in the medical journal Clinical orthopedics and clinical research suggested 37% operations supported by a significant disorder on magnetic resonance imaging were unjustified.(1)

That was 2006, certainly things have changed. Eight years later, June 30, 2014, research in the medical journal Arthritis & Rheumatology, suggested more than one third of total knee replacements in the United States were the “inappropriate” treatment. Researchers in this study, lead by Daniel Riddle, PT, PhD of the Department of Physical Therapy, Virginia Commonwealth University, found that surgeons were sending patients to knee replacement with slight to moderate osteoarthritis.(2)

In December 2017, Dr. Riddle assessed The American Academy of Orthopaedic Surgeons (AAOS) recently published appropriateness criteria for patients with knee osteoarthritis who are being considered for total knee arthroplasty  in the medical journal Osteoarthritis Cartilage. Here are the highlights:

  • The number one reason for patients seeking a knee replacement is function limiting pain
  • Functioning limiting pain is not part of the new AAOS criteria for appropriate patient selection. Rather surgeons are now looking at:
    • Patient age
    • Severity of the knee osteoarthritis
    • Structural damage to the knee causing reduced or severely impeded knee range of motion
  • This new classification tree had an accuracy of 86.7% A significant improvement from the 74=3% in Dr. Riddle’s 2014 study.(3)

Defining who is at high risk for failed knee replacement and pain

Researchers at the Department of Surgery, Southern Illinois University School of Medicine offered this assessment in the medical information publication Instructional Course Lectures:

Postoperative pain, which has been attributed to poor outcomes after total knee replacement, remains problematic for many patients. Although the source of total knee replacement pain can often be described, establishing a precise diagnosis can be challenging.

  • Pain after knee replacement can be classified as intra-articular (from within the knee) or extra-articular pain (from sources outside the knee).
  • After intra-articular causes (described below), such as knee instability, aseptic loosening, infection, or osteolysis (loss of bone), have been ruled out, extra-articular sources of pain should be considered.
  • Extra-articular sources of pain can be found after a physical examination of the other joints which may reveal sources of localized knee pain, including diseases of the spine, hip, foot, and ankle.
    • Additional extra-articular pathologies that have potential to instigate pain after total knee replacement include cardiovascular problems, tendinitis, bursitis, and iliotibial band friction syndrome.
    • Patients with medical comorbidities, such as metabolic bone disease and psychological illness, may also experience prolonged postoperative pain.(4)

In a study out of London, researchers writing in The Annals of The Royal College of Surgeons of England sought to uncover various predictors of a successful (or unsuccessful) outcome in a total knee replacement. Looking at 1,991 total knee replacement patients over a three-year period, they discovered that females and older people had worse functional outcomes following the replacement surgery.(5)

In a 2017 study from the University of Copenhagen in Denmark, pre-operative widespread pressure pain hypersensitivity and pain catastrophizing are predictive of moderate severe post-total knee replacement pain. Also interesting in this study was the impact of fear of hospitals and hospital stay anxiety.(6)

Research: Patients say, compared with preoperative health problems, post  knee replacement health problems were a bigger problem than anticipated.

One of the problems we see in patients who are having problems post-knee replacement surgery is the thinking that knee replacement works for everyone, how come it didn’t work for them? When these patients are presented with research complied from patient outcomes, they are somewhat surprised to see that they are not so unique after all, many patients have reported problems with expectations and complications of their knee replacement(s).

Knee replacement is considered one of the great innovations in musculoskeletal care. It is said to be the only known cure for knee osteoarthritis. Orthopedist surgeons routinely tell patients of the great success of the procedure. Yet, it was not until doctors started to perform outcome questionnaire studies that the medical community started to realize what patients had already. Knee replacement is not as successful as everyone thinks.

In 2016, Doctors at the University of Bristol in the United Kingdom wrote in the British Medical Journal that the problem of post surgical pain in knee replacement patients had reached a point of significance and that researchers should prioritize their studies to help people with pain. They wrote:

  • “Our systematic review highlights a lack of evidence about the effectiveness of prediction and management strategies for chronic postsurgical pain after total knee replacement. As a large number of people are affected by chronic pain after total knee replacement, development of an evidence base about care for these patients should be a research priority.”(7)

What patients want from their knee replacement:

In the November 2017 edition of the journal Medical Care, a combined research team from the University of Illinois at Chicago, China Medical University Hospital, and National Taiwan University Hospital published their findings on what concerned patients before knee replacement and the type of pre-existing conditions these patients had.

Before the surgery concerns about successful surgery circled around these factors:

  1. anxiety/depression
  2. The ability to take care of themselves immediately after the surgery.
  3. The ability to move and have mobility after the surgery.
  4. The ability  to be able to perform their own usual activities,
  5. The amount of pain and discomfort in recovery and post-op.

After the surgery, researchers found patients had to alter their recovery and post-surgery strategy to account for new health problems and problems of mobility

  1. The amount of pain and discomfort in recovery and post-op became the greatest impact of post-surgical patient non-satisfaction.
  2. Compared with preoperative health problems, postsurgical health problems were associated were a bigger problem than anticipated.
  3. Significant differences in thinking before surgery and surgical outcomes were observed including
    1. Greater problems than anticipated in:
      1. Mobility,
      2. Not being able to perform usual activities,
      3. anxiety/depression.

It is important to know that the purpose of this research was to assign a set of values to these patient problems in order to be able to come up with a formula that would better help the patient with their expectations before and after the surgery. The researchers had to conclude in the end that:

“Our systematic review highlights a lack of evidence about the effectiveness of prediction and management strategies for chronic postsurgical pain after total knee replacement.”(8)

In the end there is no way currently to predict who will get benefit and who will get worse from knee replacement surgery and patients should be counseled that there is no guarantee that knee replacement will work for them.

Patients should be counseled that there is no guarantee that knee replacement will work for them


Research: 10% to 34% of patients are not satisfied with knee replacement

In August 2017, doctors at the University Hospital Leipzig in Germany, opened their published research in the medical journal Patient safety in surgery with this statement:

  • In spite of the improvement of many aspects around Total knee arthroplasty (Total knee replacement), there is still a group of 10% to 34% of patients who is not satisfied with the outcome.
  • The therapy of chronic pain after total knee replacement remains a medical challenge that requires an interdisciplinary therapy concept. (In other words, more doctors, more providers, more treatments).

What these paper deals with is an ever growing population of people for whom knee replacement did not work.

In their paper the Leipzig researchers were looking at effective means to help the patient with pain after knee replacement, a brief summary of their findings in presented here:

“The treatment of patients with chronic complaints after total knee replacement is a challenging task. Therefore, an adequate therapy is only possible due to an interdisciplinary team of experienced orthopaedic surgeons with great knowledge in the field of endoprosthetics (knowledge of hardware failure and misfit), qualified physiotherapists (patients with problems after knee replacement often suffer from various stage of depression) and pain therapists.” (The patients are in pain, sometimes more so than before the surgery.)

The researchers than assessed the following of having some benefits:

  • Acupuncture or Traditional Chinese Medicine which assisted in reducing knee swelling in some patients
  • Gentile Physiotherapy (getting the patient to move to get circulation and reduce swelling and fluid collection in the knee).
  • Injections of bupivacaine and lidocaine for very temporary relief
  • Treatment should be supported by psychotherapists or psychologists with experiences in the area of psychosomatic medicine. (We will deal with depression and anxiety below)
  • More pain medication with caution and observation as “in most patients, a chronic abuse of pain medication was present.”

The doctors concluded that following guidelines presented, some patients could be shown to have pain improvement.(9)

Harvard Medical School’s findings surrounding the phenomena of continued pain following total knee replacement

Here are some more quick facts surrounding the phenomena of continued pain following total knee replacement from researchers at Brigham and Women’s Hospital, Harvard Medical School.

In this 2017 study published in the medical journal Osteoarthritis Cartilage, the doctors found:

  • Approximately 20% of total knee replacement recipients have suboptimal pain relief. (Suboptimal of course means not working).
  • Pre-operative widespread pain was associated with greater pain at 12-months and failure to reach clinically meaningful difference in pain, pre and post replacement
  • Patients with widespread pain along with the pain catastrophizing problems (see below), may help identify persons with suboptimal total knee replacement outcomes.(10)

Research: “Patients with persistent pain after knee replacement are dissatisfied”

That is an obvious statement, but what are the patients dissatisfied about and how can we help them? Here is the study that statement came, 2016 research in the journal Osteoarthritis Cartilage:

In the most dissatisfied knee replacement patients:

  • pain was associated with instability in the coronal plane (the center line from head to foot that marks the front of the body from the back of the body) in other words difficulty in:
    • maintaining balance.
    • Also reported were leg and knee stiffness,
    • and negative social support.

In patients who were dissatisfied on a lesser level,

  • pain was associated with patellofemoral problems,
  • elevated Body Mass Index (overweight/obese)
  • reduced local pain thresholds, inability to tolerate pain (see below)
  • depression (please see our article Psychiatric disease and joint replacement complications).(11)

Studies have demonstrated that poor management of acute pain after total knee replacement is strongly associated with development of chronic pain

In March 2017, a team of Korean doctors went further, writing in the medical journal Clinic in Orthopedic Surgery they announced:

  • Study: “postoperative pain is a major cause of dissatisfaction among patients after total knee replacement. Studies have demonstrated that poor management of acute pain after total knee replacement is strongly associated with development of chronic pain, emphasizing the importance of appropriate control of acute pain after total knee replacement”
    • Comment:
      • Knee replacement > acute pain after surgery > Inappropriate pain control.
        • Pain control of course being medications. > More chronic pain.
          • The degenerative cycle is in full force.
  • Study: “Early diagnosis is very important for the treatment of intractable pain following total knee replacement. A reoperation conducted without identification of a specific reason carries a high risk of failure.”
    • Comment:
      • Knee replacement > acute pain after surgery > Inappropriate pain control.
        • Pain control of course being medications. > Chronic pain undetermined cause > Second knee replacement operation with high rate of failure.(12)

Patients had knee pain after knee replacement because after the fact, it was determined that knee replacement was the wrong surgery. The knee was not the problem and the patient was inappropriately rushed to surgery

Are you getting a knee replacement because of undiagnosed back and hip pain? Are you getting the wrong joint operated on? Is the knee replacement wrong because it was unnecessary?

Doctors warn that in the case of chronic knee pain, a thorough examination is imperative in identifying the correct diagnosis. That sounds like common sense, but the truth is that the source of pain is often missed and treatment then will present a significant challenge with less than desired results.

One study sought to understand why up to 20 percent of patients who undergo total knee replacement still have persistent pain and why secondary surgery rates are on the rise.(13) Forty-five patients were studied. What the researchers found was somewhat shocking. The pain was not originating in the knee – here is what they said:

“Patients may still be undergoing knee (replacement) arthroplasty for degenerative lumbar spine and hip osteoarthritis. . . We suggest heightened awareness at pre- and post-operative assessment and thorough history and examination with the use of diagnostic injections to identify the cause of pain if there is doubt.”

In other words, patients received a knee replacement when the cause of pain came from the hip and spine.

In the journal Modern rheumatology, Japanese doctors wrote:

“We suggest that rheumatologists be aware of hip disease masquerading as knee pain or low back pain.” (14)

In the case of chronic joint pain, a thorough examination is imperative in identifying the correct diagnosis. That sounds like common sense, but the sad truth is that the source of pain is often missed because of misinterpretation of MRI and other imaging scans. Please see our article on MRI accuracy.

Despite the warning about knee replacement complication risks being higher when performed at local low-volume hospitals – patients still choose the local – higher risk option. In fact the researchers called these patients the “vulnerable group.”

In 2012, doctors writing in the journal BMC musculoskeletal disorders, warned patients not to go to low-volume knee replacement hospitals because the risk of complication was greater due to lack of expertise. (Yes we say the same thing about Prolotherapy – go to a high volume Prolotherapy practice).

Despite this warning about knee replacement complication risks being higher when performed at local low-volume hospitals – patients still choose the local – higher risk option. In fact the researchers called these patients the “vulnerable group.”(15)

We have identified the problems, now we will look at remedies and treatments for pain after knee replacement

The patient problems after knee replacement surgery are many. At Caring Medical and Rehabilitation Services we can address some of these problems, we cannot address all, especially when the problem of the knee replacement is caused by the hardware and the hardware’s placement.

These are the problems we will comment on:

  • The knee replacement hardware is wearing out and loosening or it was not placed in the knee correctly and stress is causing the device problems. This problem will need surgical consultation and possibly revision surgery.
  • Infection: This is during the initial recovery period. All surgeries, not only knee replacement. On prosthetic devices, bacteria can form and colonize. This problem will need consultation with the surgical group and possibly emergency medicine.
  • The implant or the surgery caused fractures in the thigh or shin bone. This problem will need consultation with the surgical group and possibly emergency medicine.
  • Knee instability and loss of range of motion, this can also lead to considerable pain.

Catastrophizing thoughts and central sensitization = catastrophic results and opioid dependence after knee replacement

Researchers in Canada writing in the Journal of Pain Research found pain catastrophizing reflects a patient’s anxious preoccupation with pain, inability to inhibit pain-related fears, amplification of the significance of pain and a sense of helplessness regarding pain.(16)

Catastrophizing thoughts are unrealistic beliefs that only the worst can happen. A person who goes into any medical treatments believing it will not work is at a significant disadvantage. A patient should relay these thoughts to his/her doctor so that appropriate action can be taken. For some patients counseling will be effective, for some therapy, for some prayer. The patients must be made aware of options that will help them move from hopelessness to cautious optimism.

A significant problem with catastrophizing thoughts that needs to be addressed is a greater risk for opioid dependence.

Doctors in Belgium write in the Bone and Joint Journal that pre-operative pain in the knee predisposes to central sensitization (catastrophizing thoughts). Pain due to osteoarthritis of the knee may also trigger neuropathic pain and may be associated with chronic medication like opioids, leading to a state of nociceptive sensitisation called ‘opioid-induced hyperalgesia’ painkillers increase chronic pain.(17)

Neuropathic knee pain after surgery – nerve damage caused by the surgery

A 2014 study from doctors in the United Kingdom published in the Bone and joint journal suggests that it is neuropathic pain that cause problems after knee replacement. That is damage to the nerves that usually occurs in surgery.(18) Neuropathic pain is an underestimated problem in patients with pain after total knee replacement. It peaks at between six weeks and three-months post-operatively. Currently doctors believe the best choice recommendations for neuropathic knee pain is pharmacologic management.

The same research team had more to say in a 2017 study that will be discussed below.

Post-surgical stress following knee replacement

Post-surgical stress: the demands of recovery and possible out of pocket expenses cause a great deal of stress in patients. In research published in the Journal of psychosomatic research that followed total knee replacement patients who reported pain and other difficulties, doctors found that “A significant percentage (20%) of patients undergoing total knee replacement reported noteworthy levels of postsurgical stress 1 and 3 months following surgery.”

Further, this distress was associated with a more difficult recovery following (the knee replacement), characterized by more severe pain and greater functional limitations. There was a significant impact of psychological processes on the postoperative recovery.(19)

Difficulty in Kneeling

Most people had difficulty kneeling because of pain or discomfort in the replaced knee. Many patients described how this limitation affected their daily lives, including housework, gardening, religious practices, leisure activities and getting up after a fall. Patients often adapted to these limitations by finding alternatives to kneeling, assistance from others or home adaptations. Many patients had accepted that they could not kneel, however some still expressed frustrated. Few patients had consulted with healthcare professionals about kneeling difficulties, and unmet needs included the provision of information about kneeling and post-operative physiotherapy.(20)

Doctors in the United Kingdom search for answers for “Mystery Pain” after Knee Replacement

The research team from 2014 we just mentioned released another study (November 2017) in the British Pain Journal. Here they made these new observations:

  • “Despite approximately 100,000 knee replacements being performed each year in England, Wales, Northern Ireland and the Isle of Man, very little is known about the types of problems that patients experience after their surgery.”
  • Our main findings are that some patients have severe pain that interferes significantly with their lives, and that a large number of them have pain sensitisation problems (heightened sense of pain), many of which can be classified as neuropathic pain (nerve damage or pain), rather than any local, nociceptive cause (pain caused by the surgical procedure).
  • However, it was not possible to categorize all patients as having either a local cause for their pain (the site of the surgery and surrounding affected tissues) or a pain sensitisation problem, as many had complex unclassifiable causes for pain, including psychosocial problems.

One in four patients with pain after knee replacement had no clear reasoning for their pain

In this study the doctors also made this remarkable observation

  • First, they excluded those who had a clear mechanical or other orthopaedic problem and found that 25% of the remainder had neuropathic-like pain, and many more had pain sensitisation, contributing to the pain problem.
    • One in four patients with pain after knee replacement had no clear reasoning for their pain
  • The researchers noted: “This is important, first, as many orthopaedic surgeons are not familiar with how to detect these patients, and second, because there are simple therapies available to treat them. Their investigation suggests that screening with the Pain Detect tool (a pre-surgery questionnaire) and a brush test for local allodynia (tests for heightened sense of pain) may be sufficient to detect this important subgroup. Furthermore, asking the patients about pain at other sites in the body could be a useful screening tool, as there was a clear relationship between pain at other sites and pain sensitisation as a cause of knee pain. This simple question could help identify patients with a pain problem as well or instead of an orthopaedic problem.

High levels of depression in their knee replacement patients

  • They found high levels of depression in their patients, among all subgroups, but it is, of course, impossible to say whether the depression preceded the knee replacement or not, or whether it was the effect of the chronic pain rather than a causative factor.
  • However, it would seem likely that surgeons should be aware of the possibility of depression and other psychological problems in this group and think about treating these issues as part of the overall management strategy.
  • High levels of pain catastrophising pre-operatively have also been found to be associated with persistent pain at 2 years post-operatively.
  • We were struck by the high prevalence of other co-morbidities, in particular of social and psychological problems in this patient group, but are unable to say how important this was to their pain problems.(21)

“Patients may need subsequent surgeries to maximize the benefits of joint replacement”

“Many patients with hip and knee arthritis have the condition in more than one of their hip or knee joints,” said the study’s lead author Dr. Gillian Hawker. “So it’s not surprising that replacing a single joint doesn’t alleviate all their pain and disability — patients may need subsequent surgeries to maximize the benefits of joint replacement.”

The study, published in the journal Arthritis & Rheumatism (April 2013), followed a group of patients with osteoarthritis and inflammatory arthritis. Only half reported a meaningful improvement in their overall hip and knee pain and disability one to two years after surgery. What’s more, researchers found the patients who had the worse knee or hip pain to begin with but fewer general health problems and no arthritis outside of the replaced joint were more likely to report benefits.

According to the study authors, nearly 83 per cent of study participants had at least two troublesome hips and or knees.

  • In general, an estimated 25 per cent of patients who undergo a single joint replacement will have another joint replacement — usually the other hip or knee — within two years.

“While demand for joint replacement surgery has increased as our population ages, physicians lack a set of established criteria to help determine what patients will benefit from surgery and at what point during the course of the disease,” said Dr. Hawker, physician-in-chief at Women’s College Hospital and a senior scientist at ICES. “As physicians, we need to do a better job of targeting treatments to the right patient at the right time by the right provider.”

Fixing Pain After Total Knee Replacement

Amputation

Three in 1000 patients will need to have their leg amputated.

The causes of the amputation were:

  • infection around the implant (83%),
  • soft-tissue deficiency surrounding the implant (23%),
  • severe bone loss (18%),
  • extensor mechanism disruption, i.e., patellar and quadricep tendon disruption (10%),
  • intractable pain (10%),
  • fracture around the implant (9%),
  • circulatory damage  (8%).

In 80% of the cases, there were more than 2 of these factors for amputation.(22)

In new research from April 2017 doctors writing in the European journal of orthopaedic surgery and traumatology wrote:

Treatment for prosthetic knee replacement is becoming more common. Infection is an arthroplasty-related complication leading to prolonged hospitalization, multiple surgical procedures, permanent loss of the implant, impaired function, impaired quality of life and even amputation of the limb.

The purpose of this study was to identify risk factors for amputation in periprosthetic infected knee through a case-control study, analyzing patients treated from January 2012 to November 2016 in a hospital with a high incidence of this diagnosis. We included 183 patients with periprosthetic knee infection; 23 required amputation as definitive management (cases).

  • We found that patients with:
    • Increased surgical time >120 min,
    • smokers,
    • obesity and
    • diabetes mellitus had an increased risk of amputation.(23)

Knee Ultrasound during Prolotherapy

Post-surgical pain and knee instability may be from the surviving ligaments

A 2011 study in the journal Orthopedics from Rush University Medical Center researchers identified the problems of knee instability as a cause of pain in knee replacement patients. Here is a summary of their findings:

  • Instability is one of the most common causes of failure of total knee replacement.
  • Acute instability is related to intraoperative injuries or excessive release of important coronal stabilizers such as the medial collateral ligament in extension or the posterolateral corner in flexion. The posterolateral corner includes
    • lateral collateral ligament,
    • popliteus tendon, and
    • popliteofibular ligament.
  • Chronic instability in extension is often related to varus/valgus malalignment. (Knee hardware problem)
  • Chronic instability in flexion can be related to an undersized femoral component, excessive tibial slope, or excessive elevation of the joint line affecting the isometry of the collateral ligaments in midflexion. (Knee hardware and anatomy problems caused by surgical mistake). (24)

Ligament instability was the primary reason for revision

Doctors writing in the German medical journal, Der Orthopäde said:

  • “In 32.6 % of all cases [requiring a revision surgery], ligament instability was the primary reason for revision.
  • In another 21.6%, ligament instability was identified as a secondary reason for revision.
  • Analysis of the different instability forms showed combined instability in extension and flexion as the most common cause, followed by isolated instability in flexion (31.8%) and isolated instability in extension (9.1%). 

The summary statement of this research is extraordinary in its simplicity

“Correct anatomical positioning of the components and balanced ligaments in the different extension and flexion positions are important for good clinical results, a stable joint, good function and longevity.”(25)

In other words, put the ligaments back where you found them.

Previous ligament reconstruction surgery – higher risk for complications after knee replacement

Doctors at the Mayo Clinic have published findings in Clinical orthopaedics and related research which they suggest that patients who had previous multi-ligament reconstruction surgery were at high risk for:

  • knee replacement complications,
  • constrained knee replacement designs (less movement),
  • and higher risk of major complications, including reoperation and infection.(26)

 

Ironically, the number one symptom that our treatments Prolotherapy, Stem Cell Prolotherapy and Platelet Rich Plasma Injections address in pre-surgery patients is ligament instability. Post-knee replacement pain problems and instability can benefit from these treatments if the problems relate to the soft tissue and ligaments:

 

If you have questions about knee replacement options, contact us for help and more information

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