How Common It Is and Who Gets It? (Epidemiology)<\/h3>\n
While knee replacement surgery is generally very successful, buckling or instability after the procedure is a complication that can occur in a minority of patients. It is more commonly seen in individuals with certain risk factors, such as obesity, poor muscle strength, pre-existing deformities (e.g., bowlegs or knock knees), or those undergoing revision knee replacement surgery. Patients with underlying conditions like rheumatoid arthritis or connective tissue diseases may also be at higher risk for knee instability after TKR.<\/p>\n
![\"Intraoperative](\"https:\/\/2025divi.cortho.org\/wp-content\/uploads\/2021\/06\/Buckling-after-Total-Knee-Replacement.jpg\" "\\"Intraoperative")
Intraoperative fluoroscopic image showing modular revision knee replacement.<\/p><\/div>\n
\u00a0<\/p>\n
What is Buckling After Total Knee Replacement?<\/strong><\/p>\n Imagine you’re walking, and suddenly your knee gives out, causing you to stumble or fall. That’s what buckling feels like. Buckling after TKR refers to a sudden and unexpected loss of strength or stability in the knee joint, leading to a feeling of instability or giving way.<\/p>\n The primary cause of buckling after TKR is instability in the knee joint, which can arise from several factors:<\/p>\n Weak Muscles<\/strong>: During surgery, muscles and tissues around the knee are disturbed, which can affect their strength and coordination.<\/p>\n<\/li>\n Proprioception Loss<\/strong>: Proprioception refers to the body\u2019s ability to sense the position of its joints. Changes in joint mechanics and nerve function after surgery can impair this ability, leading to instability.<\/p>\n<\/li>\n Surgical Factors<\/strong>: Incorrect alignment, poor positioning of the implant, or excessive tissue release during surgery may lead to joint laxity and instability.<\/p>\n<\/li>\n Infection, Implant Loosening, or Malposition<\/strong>: These complications can affect the stability of the knee, leading to buckling.<\/p>\n<\/li>\n Pre-existing Deformities<\/strong>: Conditions like bowlegs or knock knees can place excessive strain on certain parts of the knee, contributing to instability after surgery.<\/p>\n<\/li>\n<\/ul>\n The knee joint is a hinge joint formed by the femur (thigh bone), tibia (shin bone), and patella (kneecap). It is stabilized by ligaments, muscles, and tendons. The knee\u2019s function is to allow smooth, controlled movement, and balance body weight during activities like walking, running, and jumping. After knee replacement surgery, the diseased parts of the knee are replaced with prosthetic components to restore function and alleviate pain.<\/p>\n Buckling after TKR presents as a sudden loss of knee stability, often resulting in a feeling that the knee is “giving way.” This may occur during physical activities or even at rest. Other symptoms include:<\/p>\n Knee Instability<\/strong>: A sensation of the knee buckling, giving way, or feeling weak during walking or standing.<\/p>\n<\/li>\n Pain<\/strong>: Pain or discomfort in the knee joint, often associated with episodes of instability.<\/p>\n<\/li>\n Swelling<\/strong>: Inflammation around the knee joint can exacerbate instability and cause discomfort.<\/p>\n<\/li>\n Reduced Function<\/strong>: Difficulty performing activities that require weight-bearing or mobility, such as climbing stairs or walking long distances.<\/p>\n<\/li>\n<\/ul>\n Diagnosis is based on a thorough physical examination, patient history, and imaging studies. The physician will assess knee strength, alignment, and any visible signs of instability. Radiological studies such as X-rays<\/strong>, CT scans<\/strong>, or MRIs<\/strong> may be used to evaluate the alignment of the implants, detect loosening, and identify any structural issues such as bone damage or soft tissue problems.<\/p>\n Buckling after TKR can be classified based on the type of instability:<\/p>\n Varus-Valgus Instability<\/strong>: Side-to-side instability that may occur if the knee\u2019s deformity is not fully corrected during surgery or if there\u2019s excessive cutting of the femur.<\/p>\n<\/li>\n Flexion Instability<\/strong>: Front-to-back instability resulting from over-resection of the femoral condyle or issues with the tibial implant’s slope.<\/p>\n<\/li>\n Mid-Flexion Instability<\/strong>: Instability that occurs when bending the knee from 45 to 90 degrees, often due to malrotation or improper implant positioning.<\/p>\n<\/li>\n Genu Recurvatum<\/strong>: Excessive knee hyperextension, often caused by contracture of the iliotibial band, leading to instability.<\/p>\n<\/li>\n Global Instability<\/strong>: A combination of multiple types of instability, often resulting from severe bone loss or previous surgeries.<\/p>\n<\/li>\n<\/ul>\n Several conditions can cause symptoms similar to buckling after TKR, including:<\/p>\n Implant Loosening<\/strong>: A common cause of instability after knee replacement.<\/p>\n<\/li>\n Meniscal Tears<\/strong>: Damage to the menisci can cause instability or discomfort.<\/p>\n<\/li>\n Ligament Injuries<\/strong>: Damage to other knee ligaments, such as the anterior cruciate ligament (ACL), can result in instability.<\/p>\n<\/li>\n Osteoarthritis<\/strong>: Degenerative changes in the joint can cause pain and instability, particularly if the knee replacement has not fully addressed the underlying issues.<\/p>\n<\/li>\n<\/ul>\n Intraoperative image of knee replacement surgery.<\/p><\/div>\n Non-Surgical Care<\/strong><\/p>\n Physical Therapy<\/strong>: Strengthening exercises targeting the muscles around the knee, especially the quadriceps, can help improve stability and reduce episodes of buckling.<\/p>\n<\/li>\n Bracing<\/strong>: Knee braces or orthotics may provide additional support and help improve joint alignment during weight-bearing activities.<\/p>\n<\/li>\n Medications<\/strong>: NSAIDs may be prescribed to manage pain and inflammation, although they are not a direct treatment for instability.<\/p>\n<\/li>\n<\/ul>\n Surgical Care<\/strong><\/p>\n In cases where conservative measures fail, surgical intervention may be necessary. Options include:<\/p>\n Revision Surgery<\/strong>: Revision TKR involves replacing or adjusting the existing prosthetic components. Special implants, such as hinged implants or those with rotating platforms, may be used to address instability.<\/p>\n<\/li>\n Soft Tissue Repair<\/strong>: If instability is caused by damaged soft tissues, surgical repair or tightening of the ligaments and tendons may be performed.<\/p>\n<\/li>\n Realignment<\/strong>: In some cases, the alignment of the knee or prosthetic implant may need to be adjusted to correct the instability.<\/p>\n<\/li>\n<\/ul>\n Recovery from treatments for knee instability, particularly revision surgery, involves a structured rehabilitation program. This includes strengthening exercises, gait training, and range-of-motion activities. Full recovery may take several months, and the patient should gradually resume activities under the guidance of their healthcare provider.<\/p>\n Infection<\/strong>: A risk with any surgery, particularly revision surgeries.<\/p>\n<\/li>\n Blood Clots<\/strong>: Patients may be at risk for deep vein thrombosis (DVT) after surgery.<\/p>\n<\/li>\n Nerve Damage<\/strong>: Nerves around the knee may be injured during surgery.<\/p>\n<\/li>\n Implant Failure<\/strong>: Despite revision surgery, there is a risk of the new implant failing or loosening again.<\/p>\n<\/li>\n<\/ul>\n The prognosis for patients experiencing buckling after TKR depends on the underlying cause of the instability. Many patients can experience significant improvement with appropriate treatment, including physical therapy and, if necessary, revision surgery. However, some individuals may require multiple interventions to fully address the instability.<\/p>\n Medicare<\/strong><\/p>\n CPT Code 27487 \u2013 Revision Total Knee Replacement (Femoral and Tibial Components): $413.16 Under Medicare, 80% of the approved amount for these procedures is covered once your annual deductible has been met. The remaining 20% is typically the patient\u2019s responsibility. Supplemental insurance plans\u2014such as Medigap, AARP, or Blue Cross Blue Shield\u2014generally cover this 20%, leaving most patients with little to no out-of-pocket expenses for Medicare-approved knee surgeries. These supplemental plans work directly with Medicare to provide full coverage for procedures like knee replacement, soft tissue repair, and realignment surgeries.<\/p>\n If you have secondary insurance\u2014such as Employer-Based coverage, TRICARE, or Veterans Health Administration (VHA)\u2014it acts as a secondary payer once Medicare processes the claim. After your deductible is satisfied, these secondary plans may cover any remaining balance, including coinsurance or small residual charges. Secondary plans typically have a modest deductible, usually between $100 and $300, depending on the specific policy and network status.<\/p>\n Workers\u2019 Compensation<\/strong> No-Fault Insurance<\/strong> Example Q. What causes buckling after TKR?<\/strong> Q. How is buckling after TKR treated?<\/strong> Q. Can buckling after TKR be prevented?<\/strong> Buckling after total knee replacement is a concerning complication that can affect mobility and quality of life. Early recognition of the symptoms and appropriate treatment, such as physical therapy or revision surgery, is key to managing this condition. By working closely with healthcare providers, individuals can improve knee stability and regain confidence in their knee function.<\/p>\n Orthopedic surgeons specializing in knee surgery and revision surgery are responsible for diagnosing and treating buckling after TKR. Physical therapists play a key role in rehabilitation and improving knee strength and stability.<\/p>\n If you experience knee instability, buckling, or pain after TKR, it is important to consult your surgeon or healthcare provider for an evaluation and appropriate treatment.<\/p>\n Seek emergency care if you experience severe pain, swelling, or signs of infection (e.g., redness, warmth, fever) after surgery, or if you fall due to knee instability.<\/p>\n Recovery from buckling after TKR involves strengthening exercises, improving mobility, and potentially undergoing revision surgery. It can take several months to regain full function and stability.<\/p>\n Ignoring knee instability can lead to further damage to the knee joint, increased pain, and difficulty with daily activities. Timely intervention is essential to prevent complications and improve long-term outcomes.<\/p>\n Prevention involves following a prescribed rehabilitation program, avoiding premature return to high-impact activities, and maintaining good knee health to reduce the risk of buckling after TKR.<\/p>\n Maintaining a healthy diet rich in calcium and vitamin D supports bone health and can help optimize the outcomes of knee surgery.<\/p>\n Engaging in low-impact activities, maintaining a healthy weight, and following proper techniques for movements can help protect the knee joint and reduce the risk of instability.<\/p>\n [\/et_pb_text][et_pb_text admin_label=”FAQ Headline” _builder_version=”4.24.2″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n [\/et_pb_text][et_pb_df_faq admin_label=”FAQ Module – Change the FAQ Category Here” filter_by_category_on=”on” include_categories=”5342″ accordion_bg_color_closed=”#1f7714″ accordion_bg_color_open=”#1f7714″ accordion_icon_color=”#FFFFFF” accordion_icon_color_open=”#FFFFFF” _builder_version=”4.24.3″ _module_preset=”default” question_text_color=”#FFFFFF” answer_text_color=”#FFFFFF” global_colors_info=”{}”]<\/p>\n [\/et_pb_df_faq][\/et_pb_column][et_pb_column type=”1_4″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_sidebar area=”sidebar-1″ _builder_version=”4.16″ global_colors_info=”{}”]<\/p>\n [\/et_pb_sidebar][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":" Buckling after Total Knee Replacement Total knee replacement (TKR) is a highly successful surgery aimed at alleviating pain and restoring function in the knee joint. However, some patients may experience knee instability, commonly referred to as “buckling,” after the procedure. This can lead to difficulties in walking, fear of falling, and a decreased quality of […]<\/p>\n","protected":false},"author":37,"featured_media":13322,"parent":57534,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"Buckling after Total Knee Replacement - Complete Orthopedics","_seopress_titles_desc":"Knee replacement surgeries are highly successful surgeries aimed to help relieve knee pain and associated disability.","_seopress_robots_index":"","_et_pb_use_builder":"on","_et_pb_old_content":" Knee replacement surgeries<\/a> are highly successful surgeries aimed to help relieve knee pain<\/a> and associated disability. However, some patients may not have optimal results and may complain of wobbling or buckling of the knee after the surgery.<\/p> The buckling of the knee after the replacement is instability that may result from preoperative, operative, or postoperative factors. Frequently, instability after total knee replacement requires revision surgery<\/a> to address the cause of instability and prevent reoccurrence.<\/p> Knee replacement surgery consists of replacing the diseased ends of the bones forming the knee joint with metal and plastic prosthetic parts<\/a>. During the surgery, the surgeon makes bone cuts using templates at specific angles and directions to ensure a balanced artificial knee joint.<\/p> Balancing of the knee ensures that there is no excess pressure or tension on the tissues on the front, back, and sides. Additionally, with the balancing of the knee, the deformity is usually corrected, and the body weight is evenly distributed on both sides of the knee joint.<\/p>[caption id=\"attachment_13322\" align=\"aligncenter\" width=\"375\"] The instability is an early sign of failure of knee replacement. The patients may often complain of knee pain<\/a> with wobbling or buckling of the knee joint. The risk of instability is greater in patients with connective tissue and inflammatory diseases such as rheumatoid arthritis or diabetes mellitus, etc.<\/p> Patients requiring knee replacement surgery often have a preoperative knock knee or bow leg deformity. Patients with bow leg deformity have excessive laxity of tissues on the outer side of the knee while the tissues on the inner side are tight or contracted. During the surgery, the surgeon tries to lengthen the contracted tissues by releasing them from the inner side of the knee.<\/p> Similarly, in patients with a knock knee deformity who may need a joint replacement surgery, the tissues on the outer side of the knee are contracted and tight. In order to correct the deformity, the surgeon works to release the tight tissues on the outer side of the knee. Excessive release of tissues on either the inner or the outer side of the knee during replacement surgery may lead to joint laxity and instability.<\/p> Patients that may require revision knee replacement due to any reason such as infection, loosening, implant malposition, implant breakage, etc. are also at an increased risk of instability following revision surgery.<\/p> After the primary knee replacement surgery, the tissues around the knee joint may often become thick and fibrous. The thickening of the tissues may often make balancing the knee difficult during revision surgery leading to instability. Knee instability after replacement surgery is usually divided\/classified depending upon the direction of instability.<\/p> The patients experience instability in the side to side direction which may occur as a result of excessive cutting of the lower end of the thigh bone (femur), or inadequate correction of knock knee\/bow-legs deformity during the surgery.<\/p> The front-back instability may occur as a result of over resection of the back surface of the femur condyle, using a small femur implant, or excessive slope of the tibial implant. In the case of cruciate-retaining (CR) knee replacement, anterior-posterior instability may result from insufficiency of the posterior cruciate ligament.<\/p> The instability becomes evident in the form of malrotation on bending the knee from 45 degrees to 90 degrees. A number of different implants and surgical factors may contribute towards mid-flexion instability.<\/p> In some patients there may be instability in the form of excessive extension of the leg. The leg overshoots the normal straight alignment of the knee and may become fixed in overextension position as a result of contracture of the iliotibial band. The genu recurvatum deformity may be associated with diseases such as rheumatoid arthritis, Charcot disease, and poliomyelitis.<\/p>[caption id=\"attachment_13324\" align=\"aligncenter\" width=\"375\"] The instability in multiple planes after knee replacement surgery is known as global instability. Global instability often results from severe bone loss as a result of multiple surgeries.<\/p> The diagnosis of instability after a knee replacement is made by the physician based on the history of the patient including the type of surgery and any comorbid conditions. An x-ray, CT scan or MRI may be done to look for implant positioning and the surrounding bone. Blood investigations may be done in case an infection is suspected.<\/p> The treatment of knee instability after knee replacement depends upon the degree of instability and the type of instability. The management is usually surgical and bracing may be done in a small subset of patients. The revision surgery may utilize special implants to decrease instability such as hinged implants or implants with rotating platforms.<\/p>","_et_gb_content_width":"","footnotes":""},"class_list":["post-13325","page","type-page","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/pages\/13325","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/users\/37"}],"replies":[{"embeddable":true,"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13325"}],"version-history":[{"count":4,"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/pages\/13325\/revisions"}],"predecessor-version":[{"id":59089,"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/pages\/13325\/revisions\/59089"}],"up":[{"embeddable":true,"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/pages\/57534"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=\/wp\/v2\/media\/13322"}],"wp:attachment":[{"href":"https:\/\/2025divi.cortho.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13325"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Why It Happens \u2013 Causes (Etiology and Pathophysiology)<\/h3>\n
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How the Body Part Normally Works? (Relevant Anatomy)<\/h3>\n
What You Might Feel \u2013 Symptoms (Clinical Presentation)<\/h3>\n
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How Doctors Find the Problem? (Diagnosis and Imaging)<\/h3>\n
Classification<\/h3>\n
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Other Problems That Can Feel Similar (Differential Diagnosis)<\/h3>\n
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![\"Intraoperative](\"https:\/\/2025divi.cortho.org\/wp-content\/uploads\/2021\/06\/Buckling-after-Total-Knee-Replacement2.jpg\" "\\"Intraoperative")
Treatment Options<\/h3>\n
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Recovery and What to Expect After Treatment<\/h3>\n
Possible Risks or Side Effects (Complications)<\/h3>\n
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Long-Term Outlook (Prognosis)<\/h3>\n
Out-of-Pocket Costs<\/h3>\n
CPT Code 27380 \u2013 Soft Tissue Repair (Ligament\/Tendon Repair Around Knee): $148.14
CPT Code 27427 \u2013 Soft Tissue Imbrication\/Capsular Plication: $168.63
CPT Code 27418 \u2013 Realignment (Proximal Tibial\/Tibial Tubercle Osteotomy): $967.95<\/p>\n
If your knee surgery is work-related, Workers’ Compensation will fully cover all treatment-related costs, including surgery, hospitalization, and rehabilitation. You will have no out-of-pocket expenses under an accepted Workers’ Compensation claim.<\/p>\n
If your knee injury requiring surgery is the result of a motor vehicle accident, No-Fault Insurance will cover all medical and surgical expenses, including revision knee replacement, soft tissue repair, and realignment procedures. The only possible out-of-pocket cost may be a small deductible depending on your individual policy terms.<\/p>\n
Tom, a 65-year-old patient with knee arthritis, required revision total knee replacement (CPT 27487) and also underwent soft tissue repair (CPT 27380). His estimated Medicare out-of-pocket costs were $413.16 for the knee replacement and $148.14 for the soft tissue repair. Since Tom had supplemental insurance through Blue Cross Blue Shield, the 20% that Medicare did not cover was fully paid, leaving him with no out-of-pocket expenses for the surgeries.<\/p>\nFrequently Asked Questions (FAQ)<\/h3>\n
A. Buckling is primarily caused by instability in the knee joint, which may result from muscle weakness, poor implant positioning, infection, or other surgical complications.<\/p>\n
A. Treatment typically includes physical therapy, strengthening exercises, knee bracing, and, in some cases, revision surgery to replace or adjust the implants.<\/p>\n
A. While it may not be entirely preventable, following rehabilitation protocols, maintaining a healthy weight, and avoiding high-impact activities can reduce the risk of buckling.<\/p>\nSummary and Takeaway<\/h3>\n
Who Performs This Treatment? (Specialists and Team Involved)<\/h3>\n
When to See a Specialist?<\/h3>\n
When to Go to the Emergency Room?<\/h3>\n
What Recovery Really Looks Like?<\/h3>\n
What Happens If You Ignore It?<\/h3>\n
How to Prevent It?<\/h3>\n
Nutrition and Bone or Joint Health<\/h3>\n
Activity and Lifestyle Modifications<\/h3>\n
Do you have more questions?\u00a0<\/h2>\n
<\/a> Intraoperative fluoroscopic image showing modular revision knee replacement.[\/caption]Varus-valgus instability (side to side)<\/h3>
Flexion instability<\/h3>
Mid flexion instability<\/h3>
Genu recurvatum<\/h3>
<\/a> Intraoperative image of knee replacement surgery.[\/caption]Global instability<\/h3>
Diagnosis<\/h3>
Management<\/h3>