What Causes Knee Pain Years After Replacement?

Knee pain can limit walking, stair climbing, and many daily activities. These limits may reduce independence and overall well-being, especially when discomfort becomes a constant problem. For people with severe joint damage—often from osteoarthritis (OA)—knee replacement (arthroplasty) is viewed as a final option when other treatments no longer help.

Total knee replacement improves joint mechanics and lowers pain for many patients, yet relief is not guaranteed. Long-term studies show that 20 % – 30 % of recipients continue to report ongoing pain after surgery.^[1] Understanding why this pain persists helps guide the next steps in care.

Incidence Of Chronic Knee Pain After Surgery

Total knee replacement is often chosen when advanced OA or another joint injury limits walking, stair climbing, and daily tasks. Although many recipients report meaningful relief, long-term studies indicate that the operation does not guarantee long-term comfort.

A prospective survey of 272 individuals, completed 12 – 16 months after surgery, found that 107 (about 40 %) still had persistent pain.^[2] The median pain score was 3 on a 0 – 10 scale, and some reported scores as high as 5, levels similar to those noted before arthroplasty.

Follow-up analyses two to four years after surgery suggest that pain persists in 25–45% of cases, indicating that symptoms may stabilize or even intensify rather than fade.^[3] National registry data raise another point for younger, more active patients: up to 15 % of implants in people younger than 55 are revised within five years, underscoring durability concerns in this age group.^[4]

These findings suggest that structural reconstruction alone may not fully alleviate knee pain, underscoring the importance of a careful assessment when discomfort persists.

Common Causes Of Pain In The Knee After Surgery

Pain that lingers or returns after knee replacement often stems from multiple sources. Mechanical, inflammatory, and nerve-related factors frequently overlap, each adding to the discomfort. The sections below outline the most common causes.

Patellofemoral Pain Syndrome (PFPS) or Runner’s Knee

PFPS produces an aching sensation at the front of the knee near the kneecap. After knee replacement, the patella must slide through a metal or polyethylene groove. Even small changes in femoral or tibial rotation—or weakness in the quadriceps—can let the kneecap drift sideways, increasing contact pressure and triggering pain.

Patellar mal-tracking, tilt, or brief instability episodes are the usual mechanical triggers. These problems may result from mild implant misalignment, tight lateral soft tissue, or a shallow trochlear groove in the prosthesis. These issues often make stair climbing, squatting, or standing from a chair uncomfortable months or years after surgery.

Meniscus Tear

The meniscus is a crescent-shaped pad of fibrocartilage between the thighbone (femur) and shinbone (tibia). It spreads the load and absorbs shock. During knee replacement surgery, most, but not all, of this tissue is removed. Any rim that remains—especially after a unicompartmental procedure—can split or fray once walking and pivoting resume.

A new meniscus tear often forms along the unoperated joint line even when implant alignment looks normal on imaging. Typical signs include sharp joint-line pain, swelling that returns, clicking, or brief locking while bending or straightening the knee. Fluid may collect inside the joint (effusion), and kneeling or deep bending may feel unstable.

Implant Loosening Or Wear

A successful knee replacement depends on a well-fixed implant—metal and cement anchored to living bone. When that bond loosens without infection, a process known as aseptic loosening, the prosthesis can shift microscopically, causing pain. Registry data show that aseptic loosening accounts for 78.5% of revision surgeries.^[5]

Wear particles from the polyethylene insert can speed loosening. As these fragments accumulate, the body initiates an inflammatory response that leads to bone loss (osteolysis), increases micromotion, and intensifies pain. People often feel deep discomfort during weight-bearing, along with swelling or a sense of instability that worsens over time.

Nerve Injury

During knee replacement surgery, surgeons must retract soft tissue and place components near small sensory nerves. Excess traction, a direct cut, or later entrapment in scar tissue or hardware can harm these nerve fibers. Two branches are most often affected: the articular branch of the common peroneal nerve, which serves the outer knee, and the infrapatellar branch of the saphenous nerve, which supplies the front.

Damage or compression can trigger sharp or burning pain, numbness, tingling, or an “electric” sensation that worsens with activities such as kneeling, squatting, or applying pressure. Swelling may be minimal, and routine imaging often looks normal, so a careful neurological examination is needed to confirm this source of post-operative knee pain.

Other Contributing Factors 

Persistent knee pain after replacement can start outside the artificial joint. Lumbar nerve-root irritation, sacroiliac joint dysfunction, or strain in nearby muscles and tendons may all refer discomfort to the knee. In one controlled study, an intra-articular anesthetic block eased pain in 61 % of participants with radiographic OA, while 32 % felt no meaningful relief, and the remainder had a mixed response.^[6]

These results show that extra-articular sources are common. Imaging alone cannot confirm the true pain generator; many people display arthritic changes yet report no knee discomfort. Careful evaluation of the spine, pelvis, and surrounding soft tissues is therefore essential when pain persists or returns after arthroplasty.

Additional Studies On Pain After Knee Replacement

Large follow-up studies show that discomfort can remain even when an operation looks successful on imaging. 

A French health insurance database followed 1,939 recipients of knee replacements for 12 months following surgery.^[7] In that time, 47.3% began new over-the-counter pain medicine, 8.6% started nerve-pain drugs, and 5.6% required opioids. Greater drug use was linked to higher pre-operative pain, total—rather than unicompartmental—implants, and psychiatric concerns; older age lowered the risk.

A multicenter registry tracked 1,778 knees for an average of 68 months.^[8] Anterior knee pain was reported in 20.2% of cases. Considering all types of discomfort, 53.8% of patients reported knee pain, while 46.2% were pain-free. Of those with anterior pain, 87.3% noticed symptoms within the first five years, and rates were higher in individuals younger than 60 years.

A cross-sectional survey of 632 knee-replacement recipients found that 44% still felt pain three to four years after surgery and 15% rated it as severe or extreme.^[9] Together, these results demonstrate that long-term pain is a common occurrence after knee replacement, underscoring the need for careful assessment when symptoms persist.

Treatment Options For Knee Pain After Surgery

Persistent knee pain after arthroplasty is addressed in steps. Care begins with non-surgical options, progressing to implant adjustments when a mechanical problem is confirmed, and may include image-guided orthobiologic injections that help calm inflammation and support tissue healing.

Conservative Treatments

Early care starts with non-operative options that calm irritation, build strength, and improve joint mechanics:

• Targeted Physical Therapy: Strengthens quadriceps and hip muscles, restores motion, and retrains gait to lower the excess load on the replaced knee.
  

• Activity Modification: Limits high-impact or deep-flexion moves while tissues recover.
  

• Unloader or Stability Bracing: Supports the joint and shifts force away from sensitive areas during daily tasks.
  

• Medication: Short-term non-steroidal anti-inflammatory drugs or acetaminophen reduce synovial inflammation and baseline pain.
  

Image-Guided Injections: Corticosteroid or platelet-rich plasma (PRP) injections deliver anti-inflammatory or growth-factor-rich fluid to joint or peri-articular tissues, aiming to ease pain and improve function without altering implant hardware.

Surgical Revisions Or Adjustments

When non-operative care no longer controls symptoms and imaging confirms a mechanical problem, surgeons can modify or replace specific implant parts to restore proper alignment and stability.

• Polyethylene Insert Exchange: Replaces a worn liner to rebalance load and remove plastic debris that irritates tissue.
  

• Component Realignment: Corrects femoral or tibial rotation, restores the joint line, or fixes valgus–varus tilt to improve patellar tracking and ligament tension.
  

• Debridement And Surface Polishing: Clears excess cement, scar tissue, or bony overgrowth that impinges on soft tissue or limits motion.
  

• Bone-Graft Augmentation With Stemmed Components: Rebuilds areas of bone loss and gives the implant a firmer base when osteolysis has weakened fixation.
  

• Complete Revision Arthroplasty: Replaces all components when loosening, severe wear, or infection has damaged the original construct to the point where partial repair is no longer feasible.

Interventional Orthobiologics

When pain continues after non-surgical care and imaging shows the implant is stable, image-guided orthobiologic injections offer a less invasive option. These procedures utilize a person’s own cells and growth factors, which are delivered with ultrasound or fluoroscopic guidance to the exact site of the pain.

• Stem-Cell-Containing Bone Marrow Concentrate: Bone marrow is collected, processed, and injected into and around the joint. The concentrate releases signals that help calm inflammation and support the health of cartilage and soft tissue.
  
• Concentrated PRP: Directed to specific ligaments, tendons, or joint surfaces, PRP helps reduce synovial inflammation and promote tissue repair without altering the implant.

What Sets The Regenexx Approach Apart From Other Alternatives?

The Regenexx interventional orthobiologics approach pairs detailed imaging with lab-grade cell processing to create a truly patient-specific orthobiologic plan. 

First, advanced scans and laboratory tests identify the exact tissues driving pain. Next, bone marrow is drawn and processed in a sterile facility to yield stem cell-containing bone marrow concentrate at six to 20 times its native cell level. PRP is produced using a multi-spin method that concentrates growth factors significantly beyond those found in standard single-spin kits.

Both preparations are then injected under real-time ultrasound or fluoroscopy, guiding the cells directly to joint capsules, ligament attachments, or other pain generators. This precision limits off-target spread and maximises contact between the orthobiologics and damaged tissue. 

By customising both dose and delivery, procedures using Regenexx offer a less invasive option that addresses biological pain drivers without altering implant hardware or moving straight to revision surgery.

Take Control Of Your Knee Pain

Persistent knee pain after arthroplasty is not inevitable. A careful evaluation can reveal mechanical, inflammatory, or nerve drivers and guide care in clear, step-by-step approaches. Conservative options are considered first; targeted surgical fixes are implemented when necessary. 

Image-guided orthobiologic injections, such as customized Regenexx procedures, offer a less invasive choice when the implant is sound but tissues remain irritated. Working with a physician to combine the right treatments can restore movement and daily comfort. A customized plan is the next step toward lasting relief.

Find Out If Regenexx Is Right For You

1. Aoyagi K, Law LF, Carlesso L, Nevitt M, Lewis CE, Wang N, Neogi T. Post-surgical contributors to persistent knee pain following knee replacement: The Multicenter Osteoarthritis Study (MOST). Osteoarthr Cartil Open. 2023 Jan 18;5(1):100335. doi: 10.1016/j.ocarto.2023.100335. PMID: 36798734; PMCID: PMC9926203. https://pmc.ncbi.nlm.nih.gov/articles/PMC9926203/
2.  Sakellariou VI, Poultsides LA, Ma Y, Bae J, Liu S, Sculco TP. Risk Assessment for Chronic Pain and Patient Satisfaction After Total Knee Arthroplasty. Orthopedics. 2016;39(1):55-62. doi:10.3928/01477447-20151228-06
3. Wylde V, Hewlett S, Learmonth ID, Dieppe P. Persistent pain after joint replacement: prevalence, sensory qualities, and postoperative determinants. Pain. 2011;152(3):566-572. doi:10.1016/j.pain.2010.11.023
   
4. Kuipers BM, Kollen BJ, Bots PC, et al. Factors associated with reduced early survival in the Oxford phase III medial unicompartment knee replacement. Knee. 2010;17(1):48-52. doi:10.1016/j.knee.2009.07.005
5. Schiffner E, Latz D, Karbowski A, Grassmann JP, Thelen S, Windolf J, Jungbluth P, Schneppendahl J. Loosening of total knee arthroplasty – always aseptic? J Clin Orthop Trauma. 2020 Mar;11(Suppl 2):S234-S238. doi: 10.1016/j.jcot.2019.05.001. Epub 2019 May 7. PMID: 32189947; PMCID: PMC7068007. https://pmc.ncbi.nlm.nih.gov/articles/PMC7068007/
6. Ikeuchi M, Izumi M, Aso K, Sugimura N, Tani T. Clinical characteristics of pain originating from intra-articular structures of the knee joint in patients with medial knee osteoarthritis. Springerplus. 2013 Nov 23;2:628. doi: 10.1186/2193-1801-2-628. PMID: 24386615; PMCID: PMC3877413.https://pubmed.ncbi.nlm.nih.gov/24386615/
7. Fuzier R, Serres I, Bourrel R, Palmaro A, Montastruc JL, Lapeyre-Mestre M. Analgesic drug consumption increases after knee arthroplasty: a pharmacoepidemiological study investigating postoperative pain. Pain. 2014 Jul;155(7):1339-1345. doi: 10.1016/j.pain.2014.04.010. Epub 2014 Apr 13. PMID: 24727347. https://pubmed.ncbi.nlm.nih.gov/24727347/
   
8. Metsna V, Vorobjov S, Märtson A. Prevalence of anterior knee pain among patients following total knee arthroplasty with nonreplaced patella: a retrospective study of 1778 knees. Medicina (Kaunas). 2014;50(2):82-6. doi: 10.1016/j.medici.2014.06.001. Epub 2014 Jun 28. PMID: 25172601. https://pubmed.ncbi.nlm.nih.gov/25172601/
9. Wylde, Vikkia,*; Hewlett, Sarahb; Learmonth, Ian D.a; Dieppe, Paulc. Persistent pain after joint replacement: Prevalence, sensory qualities, and postoperative determinants. Pain 152(3):p 566-572, March 2011. | DOI: 10.1016/j.pain.2010.11.023

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile