Some scar tissue after a knee replacement is expected, because scarring is part of how the knee heals. It becomes a problem when the body keeps laying down scar past the point it should stop and the knee stiffens.1Cory Calendine, MD. Arthrofibrosis After Knee Replacement: Causes and Treatment You usually can’t dissolve scar with a cream or pill. It gets stretched, broken up, or cut out, and the gentlest effective option comes first. Timing matters a great deal, since the same treatments work far better in the first few months than later.
Normal Stiffness or a Scar Tissue Problem
The scar problem has a name: arthrofibrosis. It is excessive new scar tissue that limits how far the knee bends and straightens, causes pain, and makes daily tasks hard.2Cory Calendine, MD. Arthrofibrosis After Knee Replacement: Causes and Treatment It happens because the cells that make scar stay switched on and keep producing tough collagen fibers.3PubMed. Arthrofibrosis After Total Knee Arthroplasty: A Critical Analysis Review It is the most common cause of a stiff knee replacement, affecting roughly 1 to 17 in 100 people depending on how it’s defined.4PubMed Central. Stiffness in total knee arthroplasty The scar tends to fill the space above the kneecap and along the sides of the joint, tethering the front of the knee.5PubMed Central. Stiffness in total knee arthroplasty
Normal early stiffness tends to ease gradually as swelling goes down and the thigh muscle wakes up. Your measurements creep upward even if some days feel worse than others. Scar-type stiffness is more likely when progress flattens out for weeks despite steady effort, or when the knee seems to hit a firm stop instead of just feeling sore or heavy. In the first weeks after surgery, swelling, healing tissue, and weak, reluctant thigh muscles all limit how far the knee moves.6Avid Sports Medicine. Scar Tissue After Knee Replacement: When Stiffness Becomes A Problem No single sign proves scar tissue. Surgeons judge it from your measurements over time, the feel of the end point when they move the knee, and your timeline since surgery. Infection or implant position can also stiffen a new knee, so a surgeon’s exam is how you tell scar from those causes, not guessing at home.
Some signs are worth raising with your surgeon or therapist: motion that stops improving or slips backward between visits, a knee that feels tight or blocked at the end of a bend rather than just sore, and trouble with stairs, getting out of a chair, or sitting in a car. Ask for your bend and straighten measurements in degrees at each visit so you can track progress.
Who Is More Likely to Develop It
- A knee that was already stiff before surgery is more likely to stay stiff afterward.7Cory Calendine, MD. Arthrofibrosis After Knee Replacement: Causes and Treatment
- Earlier knee surgery or a fracture leaves old scar that gives new scar a head start.8Cory Calendine, MD. Arthrofibrosis After Knee Replacement: Causes and Treatment
- Younger patients and men have higher rates.9Cory Calendine, MD. Arthrofibrosis After Knee Replacement: Causes and Treatment
- People with other over-scarring conditions, such as Dupuytren’s contracture in the palm or keloid scars, share the same overactive healing response.10Cory Calendine, MD. Arthrofibrosis After Knee Replacement: Causes and Treatment
- Pain or swelling that keeps the knee from moving lets scar set in, so controlling pain so you can keep exercising is part of treatment.11Cory Calendine, MD. Arthrofibrosis After Knee Replacement: Causes and Treatment
Having one or more of these does not mean you will get excess scar tissue, and many people with none still get stiff. If you have risk factors, tell your surgeon about keloids, Dupuytren’s, or past knee operations before surgery. Expect to get your motion checked more often, and raise stiffness early instead of waiting for the next routine visit.
Physical Therapy and At-Home Work Come First
Supervised physical therapy after surgery is the first line of defense against excess scar tissue.12PubMed. Arthrofibrosis Associated With Total Knee Arthroplasty How well it works depends on getting the timing, intensity, and progression right for your pain level and ability.13PubMed. Arthrofibrosis Associated With Total Knee Arthroplasty Early, structured therapy can improve motion, walking, strength, and pain.14Charles University. Case Study of the Effect of Physiotherapeutic Intervention in a Patient after Total Knee Replacement
A typical visit starts with the therapist measuring how far your knee bends and straightens, so each visit has a number to compare against. Hands-on work often follows, with the therapist pressing and gliding the kneecap and the soft tissue around it to loosen tight areas. Then you do guided exercises such as heel slides, stretches, and strengthening, with the therapist adjusting how hard you push. You leave with a home program that changes as your measurements change.
Adding hands-on joint mobilization to exercise eased pain and improved walking and daily function more than exercise alone.15PubMed Central / PM&R. The Combination of Exercise and Manual Therapy Versus Exercise Alone in Total Knee Arthroplasty Rehabilitation: A Randomized Controlled Clinical Trial Therapists may also use metal tools to work deeper scar, usually combined with stretching and active movement.16Elite Learning. Soft Tissue Work for Complications of Total Knee Arthroplasty That work involves stroking a smooth metal edge over the skin around the knee, usually with lotion. It can feel tender, and mild redness or bruising afterward can happen, so tell the therapist if it is more than you can tolerate. It is an add-on to stretching and movement, so a session without exercise is unlikely to gain you lasting motion. Splinting is another add-on that can help.17PubMed. Arthrofibrosis Associated With Total Knee Arthroplasty
Your home routine matters as much as the sessions. Do your prescribed bending and straightening exercises several times a day, not just at appointments. Ice and elevate after exercise to keep swelling down, and take pain medicine as prescribed before therapy so you can move further. Work up gradually, because forcing past sharp pain can inflame the knee and backfire.
A knee that can’t fully straighten makes walking tiring and uneven. Don’t rest with a pillow under the knee, which lets it set in a bent position, and ask your therapist for specific straightening stretches.
A motion machine is a device that bends and straightens your knee for you while you lie in bed. Combined with therapy, it improved bending at 2 weeks and reduced the need for a manipulation in pooled results.18PubMed. Efficacy of continuous passive motion following total knee arthroplasty: a metaanalysis But by 6 weeks to 3 months, people using one longer had no more motion than those doing therapy alone.19PubMed Central. Effectiveness of prolonged use of continuous passive motion (CPM), as an adjunct to physiotherapy, after total knee arthroplasty It is not a substitute for your own exercise. If motion stalls in the first 6 to 12 weeks, ask whether a manipulation is worth discussing, because waiting too long can make the next step less effective.
Manipulation Under Anesthesia Works Best Early
In a manipulation under anesthesia, the surgeon bends your knee while you’re asleep or numbed to tear loose scar, with no incision. Some surgeons add a steroid injection into the knee at the same time to ease pain and calm the inflammation that drives more scar.20PubMed Central. The results of knee manipulation for stiffness after total knee arthroplasty with or without an intra-articular steroid injection
It works because the knee is forced through a range the scar won’t allow while you’re awake, and anesthesia relaxes the muscles so the scar, rather than muscle guarding, is what gives way. Tearing scar loose doesn’t remove it, so the knee can tighten again unless you keep it moving afterward. It is aimed at scar, so it is less suited to stiffness from implant position or other mechanical problems, which your surgeon checks for first.
Timing changes results. Manipulations within 12 weeks of surgery gained about 36 degrees of bending, versus 17 degrees when done later.21PubMed. The effect of timing of manipulation under anesthesia to improve range of motion and functional outcomes following total knee arthroplasty Early patients ended with about 119 degrees of total motion, versus 95 degrees for later ones.22PubMed. The effect of timing of manipulation under anesthesia to improve range of motion and functional outcomes following total knee arthroplasty Manipulations after 6 months gave unsatisfactory results.23PubMed. The effect of timing of manipulation under anesthesia to improve range of motion and functional outcomes following total knee arthroplasty One group found even 6 weeks made a difference, with earlier manipulation bringing final bending close to people who never needed one.24PubMed. Risk Factors, Outcomes, and Timing of Manipulation Under Anesthesia After Total Knee Arthroplasty Another found knees treated after 3 months still gained motion, so later isn’t hopeless.25PubMed Central. Efficacy of manipulation under anesthesia beyond three months following total knee arthroplasty Because results fall off with time, ask your surgeon for a clear date by which you will decide, rather than letting weeks drift.
The procedure is usually short, often same day. Expect soreness and swelling for several days. Therapy restarts right away, often within a day, and some doctors send you home with a motion machine, though not everyone gets one.26OrthoInfo. Manipulation Under Anesthesia After Knee Replacement About 90 degrees of bend lets you sit in a chair and climb stairs more easily, and getting up from low seats needs more.
Steroid Injections and Shock Wave Therapy
After a steroid injection into a replaced knee, about 3 in 4 people had less pain and close to 6 in 10 moved better.27PubMed. Intra-articular Corticosteroid Injection Following Total Knee Arthroplasty: Is It Effective? The improvement lasted more than a month for only about half.28PubMed. Intra-articular Corticosteroid Injection Following Total Knee Arthroplasty: Is It Effective? A steroid reduces inflammation, so it helps most when pain and swelling are what keep you from moving. If the limit is mainly firm scar, calming inflammation may not change your motion much. The benefit is a window, often a matter of weeks, in which therapy can gain ground.
Before an injection, ask how it fits with your therapy plan and how soon you should push exercises afterward. Ask about infection risk too, since any needle into a joint replacement carries some.
Shock wave therapy started early after surgery improved bending and walking speed at one week more than standard care.29PubMed. Early application of extracorporeal shock wave therapy improves pain control and functional scores in patients undergoing total knee arthroplasty: a randomized controlled trial That evidence covers only the first week, so long-term benefit is unknown.
Surgery to Cut Out Scar Tissue
In keyhole surgery, the surgeon works through a few small cuts, using a camera to see inside, and trims scar from the front, sides, and the pouch above the kneecap. Loose pieces or pinched tissue can be removed too.30PubMed Central. Arthroscopic Lysis of Adhesions for the Stiff Total Knee Arthroplasty In one series, knee scores rose from 48 to 86, and only 1 of 27 patients failed to improve.31PubMed Central. Arthroscopic Arthrolysis of the Knee Joint Following Total Knee Arthroplasty In a smaller series only 6 of 8 improved.32PubMed Central. Arthroscopic arthrolysis for arthrofibrosis of the knee after total knee replacement
It is typically considered when therapy and the manipulation haven’t restored enough motion and the implant is judged to be well placed. Because the implant stays in, recovery is generally easier than a revision, though the knee still needs a few weeks of careful rehab.
Revision means removing the existing implant and putting in a new one, a bigger operation. It is usually considered when stiffness is severe or linked to a problem with the implant, such as its size or position. For severe cases, the implant can be replaced with a hinged design, sometimes with low-dose radiation to curb new scar.33PubMed. Low-Dose Irradiation and Rotating-Hinge Revision for the Treatment of Severe Idiopathic Arthrofibrosis Following Total Knee Arthroplasty: A Review of 60 Patients With a Mean 6-Year Follow-Up With that approach about 8 in 10 reached at least 90 degrees of bending, but about 1 in 4 still needed a manipulation afterward.34PubMed. Low-Dose Irradiation and Rotating-Hinge Revision for the Treatment of Severe Idiopathic Arthrofibrosis Following Total Knee Arthroplasty: A Review of 60 Patients With a Mean 6-Year Follow-Up The more surgeries a knee has had before, the worse the final motion.35PubMed. Low-Dose Irradiation and Rotating-Hinge Revision for the Treatment of Severe Idiopathic Arthrofibrosis Following Total Knee Arthroplasty: A Review of 60 Patients With a Mean 6-Year Follow-Up About 3 in 10 people are no better or worse after revision for scar tissue.36PubMed. Revision Total Knee Arthroplasty for Arthrofibrosis Replacing the parts doesn’t guarantee scar won’t form again. Recovery from either operation starts with intensive therapy almost immediately, and after revision you should expect several months of rehab.
Keeping Scar Tissue From Coming Back
Even if a manipulation restores full motion, skipping exercises lets the scar re-form and stiffen the knee again.37OrthoInfo. Manipulation Under Anesthesia After Knee Replacement The weeks right after any treatment are when daily exercise matters most, so you may be asked to exercise more often than before. As motion holds steady, your therapist will usually space out visits, but the home exercises continue much longer. A short plateau is common, but steady loss of motion is a signal to call your care team.
No food or supplement has been shown to dissolve knee scar. Check with your doctor before taking supplements around surgery.
Pain That Lingers and New Treatments Ahead
Scar around the kneecap can raise pressure on the joint and cause pain.38PubMed Central. Literature review of the causes of pain following total knee replacement surgery: prosthesis, inflammation and arthrofibrosis Soreness from exercise fades within a day or so, while scar-related pain tends to sit at the same spots, such as around the kneecap, and comes with a feeling of tightness. Persistent pain that doesn’t improve with time deserves an evaluation, because it can have causes other than scar. Anxiety and dwelling on pain before surgery predict worse pain afterward,39PubMed Central. Psychological determinants of problematic outcomes following Total Knee Arthroplasty so getting help for worry about pain can be part of recovery.
A key signaling protein switches on scar-making cells.40PubMed. Arthrofibrosis After Total Knee Arthroplasty: A Critical Analysis Review Drugs that block it, and others such as losartan, hyaluronic acid, and collagenase, are being studied.41PubMed Central. Pathological mechanisms and therapeutic outlooks for arthrofibrosis These are still in trials, not standard care.