The pain that did not go away after knee replacement
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. See our main page, Prolotherapy for knee pain to learn more about our regenerative treatments for knee pain.
Doctors are looking for the causes of pain after knee replacement and it is challenging
Researchers at the Department of Surgery, Southern Illinois University School of Medicine offered this assessment in the medical information publication Instructional Course Lectures to guide doctors trying to help patients with pain after knee replacement.
Point #1 Establishing a precise diagnosis of where the pain is coming from can be challenging.
This is what doctors need to look for in trying to find the source of knee pain after knee replacement:
- 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. (STOP HERE: Let’s stop for a moment. After the knee replacement, you still have knee pain. The doctors in this study are saying examine the spine, the hips, the ankles, the feet, these joints may be causing the knee pain problem. What if these joints were the cause of knee pain in the first place? See below, was knee replacement the wrong surgery?)
- Additional extra-articular pathologies that have the 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.(1)
Patients at greater risk? Women, older people, sufferers of depression and anxiety
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.(2)
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.(3)
Post knee replacement health problems are a bigger problem than anticipated
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.”(4)
Here are findings released (November 2017) in the British Pain Journal.
- “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.(5)
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:
- The ability to take care of themselves immediately after the surgery.
- The ability to move and have mobility after the surgery.
- The ability to be able to perform their own usual activities,
- The amount of pain and discomfort during 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
- The amount of pain and discomfort in recovery and post-op became the greatest impact of post-surgical patient non-satisfaction.
- Compared with preoperative health problems, postsurgical health problems were associated were a bigger problem than anticipated.
- Significant differences in thinking before surgery and surgical outcomes were observed including
- Greater problems than anticipated in:
- Not being able to perform usual activities,
- Greater problems than anticipated in:
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.”(6)
In the end there is no way currently to predict who will 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 are 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 this 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 is 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 then 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.(7)
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 a 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.(8)
Research: “Patients with persistent pain after knee replacement are dissatisfied”
That is an obvious statement, but what are the patients dissatisfied with 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).(9)
Studies have demonstrated that poor management of acute pain after total knee replacement is strongly associated with the 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 the development of chronic pain, emphasizing the importance of appropriate control of acute pain after total knee replacement”
- Our Comment:
- Patient has knee replacement
- Patient suffers from acute pain after surgery
- Painkillers and other medications are prescribed to control a patient’s pain. Acute pain turns into chronic pain
- Our Comment:
With nowhere else to go, doctors suggest another knee replacement.
- Study: “Early diagnosis is very important for the treatment of intractable (hard to control) pain following total knee replacement. A reoperation conducted without identification of a specific reason carries a high risk of failure.”(10)
- Patient has knee replacement
- Patient suffers from acute pain after surgery
- Doctors cannot control pain
- With nowhere else to go, doctors suggest another knee replacement.
- Second knee replacement operation with a high rate of failure.
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? Above we spoke about doctors looking for knee pain that was actually coming from the spine, hip, ankle, and feet. The knee was perhaps not the problem and the patient was inappropriately rushed to surgery
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.(11) 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 for degenerative lumbar spine and hip osteoarthritis
“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.” (12)
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.”(13)
Knee replacement complications in former athletes
In a recent paper, doctors from NYU Langone Medical Center, Hospital for Joint Diseases suggest that total knee arthroplasty (replacement) is often the best answer for end-stage, post-traumatic osteoarthritis after intra-articular (inside) and periarticular (around) osteoarthritic fractures the knee.
However, total knee replacement in the setting of post-traumatic osteoarthritis is often considered more technically demanding surgery and the surgical outcomes are typically worse for these patients. The goal of the NYU paper was to create a new classification label for post-traumatic osteoarthritis patients and improve medical documentation and improve patient care.
- The researchers looked at post-traumatic osteoarthritis patients who suffered from osteoarthritis as a result of high demand or athletic activity. These were on average were younger and healthier than the primary total knee replacement population (older patients with degenerative arthritis from wear and tear).
- The the healthier post-traumatic total knee replacement group had the following complications:
- higher rates of superficial surgical site infections,
- bleeding requiring transfusion,
- prolonged operative time,
- increased length of hospital stay,
- and 30-day hospital readmission.(14)
In a similar study, doctors at Duke University also recognized that Total Knee Arthroplasty as an important treatment for post-traumatic arthritis. However, these researchers also found complications that should not be expected in a mostly healthy patient population.
- a higher rate of infection around the knee implant
- cellulitis (skin infection)
- seroma (fluid build)
- knee wound complications (problems at the surgical incisions)
- need for a revision surgery.(15)
The patient problems after knee replacement surgery are many. At Caring Medical we can address many of these problems, we cannot address all, especially when the problem of the knee replacement is caused by hardware failure and hardware placement failure
- PROBLEM: 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.
- PROBLEM: Infection. This is during the initial recovery period. On prosthetic devices, bacteria can form and colonize. This problem will needa consultation with the surgical group and possibly emergency medicine.
- PROBLEM: The implant or the surgery caused fractures in the thigh or shin bone. This problem will need a consultation with the surgical group and possibly emergency medicine.
- PROBLEM: Knee prosthesis instability and loss of range of motion (it gets stuck), this can also lead to considerable pain.
Problem: 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.(16) 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. For a discussion on Prolotherapy and nerve damage see our article on Neurofascial Prolotherapy.
The same research team had more to say in a 2017 study that will be discussed below.
Problem: 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.(17)
Problem: 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.(18)
Problem: Fixing Pain After Total Knee Replacement may include 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.(19)
In 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,
- obesity and
- diabetes mellitus had an increased risk of amputation.(20)
One place we can help: The often overlooked and ignored cause of pain after knee replacement – the Knee Ligaments.
Post-surgical pain and knee instability may be from the surviving ligaments
A 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). (21)
Ligament instability was the primary reason for repair surgery
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%).
Put the ligaments back where you found them
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.”(22)
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.(23)
Pain after knee replacement – find the cause, make a realistic assessment of the situation
We may be able to help you with your pain after knee replacement. If you have questions about knee replacement options, contact us for help and more information
1 Manning BT, Lewis N, Tzeng TH, Saleh JK, Potty AG, Dennis DA, Mihalko WM, Goodman SB, Saleh KJ. Diagnosis and Management of Extra-articular Causes of Pain After Total Knee Arthroplasty. Instructional course lectures. 2015;64:381-8. [Google Scholar]
2 Ibrahim T, Bloch B, Esler CN, Abrams KR, Harper WM. Temporal trends in primary total hip and knee arthroplasty surgery: results from a UK regional joint register, 1991–2004. The Annals of The Royal College of Surgeons of England. 2010 Apr;92(3):231-5. [Google Scholar]
3 Luna IE, Kehlet H, Petersen MA, Aasvang EK. Clinical, nociceptive and psychological profiling to predict acute pain after total knee arthroplasty. Acta Anaesthesiologica Scandinavica. 2017 May 16. [Google Scholar]
4 Beswick AD, Wylde V, Gooberman-Hill R. Interventions for the prediction and management of chronic postsurgical pain after total knee replacement: systematic review of randomised controlled trials. BMJ open. 2015 May 1;5(5):e007387. [Google Scholar]
5 Phillips JR, Hopwood B, Stroud R, Dieppe PA, Toms AD. The characterisation of unexplained pain after knee replacement. British Journal of Pain. 2017 Nov;11(4):203-9. [Google Scholar]
6 Pickard AS, Hung YT, Lin FJ, Lee TA. Patient Experience-based Value Sets: Are They Stable? Med Care. 2017 Nov;55(11):979-984. [Google Scholar]
7 Zajonz D, Fakler JK, Dahse AJ, Zhao FJ, Edel M, Josten C, Roth A. Evaluation of a multimodal pain therapy concept for chronic pain after total knee arthroplasty: a pilot study in 21 patients. Patient Safety in Surgery. 2017 Aug 30;11(1):2 [Google Scholar]
8 Dave AJ, Selzer F, Losina E, Usiskin I, Collins JE, Lee YC, Band P, Dalury DF, Iorio R, Kindsfater K, Katz JN. The association of pre-operative body pain diagram scores with pain outcomes following total knee arthroplasty. Osteoarthritis and cartilage. 2017 May 31;25(5):667-7 [Google Scholar]
9 Howells N, Murray J, Wylde V, Dieppe P, Blom A. Persistent pain after knee replacement: do factors associated with pain vary with degree of patient dissatisfaction? Osteoarthritis Cartilage. 2016 Aug 9. [Google Scholar]
10 Lim H-A, Song E-K, Seon J-K, Park K-S, Shin Y-J, Yang H-Y. Causes of Aseptic Persistent Pain after Total Knee Arthroplasty. Clinics in Orthopedic Surgery. 2017;9(1):50-56. [Google Scholar]
11 Al-Hadithy N, Rozati H, Sewell MD, Dodds AL, Brooks P, Chatoo M. Causes of a painful total knee arthroplasty. Are patients still receiving total knee arthroplasty for extrinsic pathologies? Int Orthop. 2012 Jan 11. [Google Scholar]
12 Nakamura J, Oinuma K, Ohtori S, et al. Distribution of hip pain in osteoarthritis patients secondary to developmental dysplasia of the hip. Mod Rheumatol. 2012 Apr 11. [Google Scholar]
13 Lau RL, Perruccio AV, Gandhi R, Mahomed NN. The role of surgeon volume on patient outcome in total knee arthroplasty: a systematic review of the literature.BMC Musculoskeletal Disorders. 2012;13:250. [Google Scholar]
14 Kester BS, Minhas SV, Vigdorchik JM, Schwarzkopf R. Total Knee Arthroplasty for Posttraumatic Osteoarthritis: Is it Time for a New Classification? J Arthroplasty. 2016 Aug;31(8):1649-1653.e1. [Google Scholar]
15 Bala A, Penrose CT, Seyler TM, Mather RC 3rd, Wellman SS, Bolognesi MP. Outcomes after Total Knee Arthroplasty for post-traumatic arthritis. Knee. 2015 Dec;22(6):630-9. doi: 10.1016/j.knee.2015.10.004. Epub 2015 Oct 31. [Google Scholar]
16 Phillips JR, Hopwood B, Arthur C, Stroud R, Toms AD. The natural history of pain and neuropathic pain after knee replacement. Bone Joint J. 2014 Sep 1;96(9):1227-33. [Google Scholar]
17 Cremeans-Smith JK, Greene K, Delahanty DL. Symptoms of postsurgical distress following total knee replacement and their relationship to recovery outcomes. J Psychosom Res. 2011 Jul;71(1):55-7. [Google Scholar]
18 Fletcher D, Moore AJ, Blom AW, Wylde V. An exploratory study of the long-term impact of difficulty kneeling after total knee replacement. Disability and rehabilitation. 2017 Dec 4:1-6. Bristol Medical School, University of Bristol [Google Scholar]
19. Gottfriedsen TB1, Schrøder HM, Odgaard A. Transfemoral Amputation After Failure of Knee Arthroplasty: A Nationwide Register-Based Study. J Bone Joint Surg Am. 2016 Dec 7;98(23):1962-1969. [Google Scholar]
20 Polanco-Armenta AG, Miguel-Pérez A, Rivera-Villa AH, Barrera-García MI, Sánchez-Prado MG, Vázquez-Noya A, Vidal-Cervantes F, de Jesús Guerra-Jasso J, Pérez-Atanasio JM. Risk factors for amputation in periprosthetic knee infection. European Journal of Orthopaedic Surgery & Traumatology. 2017 Apr 7:1-5. [Google Scholar]
21. Del Gaizo DJ, Della Valle CJ.Instability in primary total knee arthroplasty. Orthopedics. 2011 Sep 9;34(9):e519-21. doi: 10.3928/01477447-20110714-46. [Google Scholar]
22. Graichen H, Strauch M, Katzhammer T, Zichner L, von Eisenhart-Rothe R. Ligament instability in total knee arthroplasty–causal analysis. Der Orthopade. 2007 Jul;36(7):650-2. [Google Scholar]
23. Pancio SI, Sousa PL, Krych AJ, Abdel MP, Levy BA, Dahm DL, Stuart MJ. Increased Risk of Revision, Reoperation, and Implant Constraint in TKA After Multiligament Knee Surgery. Clin Orthop Relat Res. 2017 Jun;475(6):1618-1626. [Google Scholar]