**By Matthew Sloan, MD | The Joint Replacement Podcast | Episode #67**
**Estimated reading time: 8 minutes**
You’ve had a hip or knee replacement. Recovery seems to be going well. Then one day, something unexpected happens.
Your knee makes a loud clicking sound when you stand up. Your hip feels sore after a longer walk. Your knee is still warm and swollen three months after surgery.
And suddenly, you’re wondering:
**Is this normal healing, or is my joint replacement failing?**
It’s one of the most common concerns patients experience after joint replacement surgery.
The good news is that many symptoms that cause anxiety during recovery—including clicking, stiffness, intermittent swelling, and occasional soreness—are not necessarily signs of a problem with the implant.
However, certain symptoms can indicate complications such as infection, instability, fracture, or implant loosening.
In Episode #67 of *The Joint Replacement Podcast*, I explain seven important warning signs after hip and knee replacement, how to distinguish them from normal recovery, and when you should contact your surgeon.
The most important concept to understand is simple:
**Your implant can be functioning perfectly while the muscles, tendons, ligaments, nerves, and other tissues surrounding it are still healing.**
Let’s break down what patients need to know.
—
## 1. Clicking and Clunking: Is Your Implant Loose?
One of the most common questions patients ask after knee replacement is:
“Why does my new knee make clicking noises?”
Knee replacements contain metal and highly durable polyethylene components. Unlike the natural joint, these artificial surfaces can produce audible or noticeable clicking during movement.
As postoperative swelling decreases, some patients actually become more aware of these sensations.
Tendons and other soft tissues moving around the joint can also contribute to clicking or popping.
### What’s usually normal?
– Painless clicking when bending or straightening the knee
– Occasional clunking without significant pain
– Noise that occurs during otherwise normal joint movement
– A knee that feels stable despite making noise
**The presence of clicking alone does not mean your implant is loose or failing.**
### When should you be concerned?
Contact your surgeon if clicking is accompanied by:
– New or worsening pain
– Repeated episodes of the knee giving way
– Significant new swelling
– Sudden loss of function
– A painful mechanical sensation that wasn’t previously present
A hip replacement that suddenly becomes extremely painful, deformed, or impossible to bear weight on may indicate a dislocation or fracture and requires emergency evaluation.
**Bottom line:** Noise is usually less important than pain, stability, and function.
## 2. Pain After Joint Replacement: Normal Soreness or Implant Failure?
Recovery from joint replacement isn’t linear.
You might feel great on Monday, slightly worse on Tuesday, and better again by Wednesday.
That’s especially common when patients begin increasing their activity.
For example, you might walk farther than usual, spend more time standing, or progress your physical therapy exercises. The following day, your muscles and joint feel sore.
That doesn’t automatically mean you’ve damaged your replacement.
### What’s usually normal?
– Muscle soreness after increased activity
– Stiffness after sitting for prolonged periods
– Discomfort that improves with rest and appropriate swelling-control measures
– Mild fluctuations in pain during recovery
– An overall trend toward improvement over weeks and months
Healing tissues need time to adapt to the new mechanics of the joint.
### What pain patterns are concerning?
Certain patterns deserve additional evaluation:
– Pain that progressively worsens rather than improves
– New, deep, persistent pain around the replacement
– Severe pain at rest or pain that repeatedly awakens you from sleep
– Sudden severe pain following a fall or twisting injury
– Pain associated with fever, swelling, redness, or new instability
It’s important to recognize that not all pain after joint replacement originates from the implant.
Muscles, tendons, nerves, the lower back, and surrounding joints can all contribute to discomfort.
However, persistent or progressively worsening pain shouldn’t simply be dismissed as normal recovery.
**Bottom line:** The overall trajectory matters more than any isolated episode of soreness.
## 3. Swelling After Knee Replacement: How Long Is Normal?
Patients are often surprised by how long swelling can persist after knee replacement.
Even when the implant is functioning perfectly, the surrounding tissues may remain inflamed for months.
Some patients notice that their knee looks relatively normal in the morning but becomes progressively swollen throughout the day.
Others notice increased tightness after longer walks, standing, or exercise.
### What’s usually normal?
– Mild to moderate swelling during recovery
– Swelling that increases with activity
– Swelling that improves with rest, ice, and elevation
– Gradually decreasing swelling over several months
– Occasional swelling after particularly active days
Some residual swelling can last six months or longer, although the pattern and duration vary considerably between patients.
### When is swelling a warning sign?
Be concerned about:
– Sudden, dramatic swelling without an obvious explanation
– Rapidly increasing swelling accompanied by severe pain
– Significant swelling with redness or fever
– New calf pain, tenderness, or swelling
That last point is especially important.
**New calf swelling or pain after joint replacement could indicate a deep vein thrombosis (DVT), or blood clot.**
This requires prompt medical evaluation.
Chest pain, sudden shortness of breath, or coughing up blood could indicate a pulmonary embolism and requires emergency medical attention.
**Bottom line:** Mild activity-related swelling can be normal. Rapid, unexplained swelling should not be ignored.
## 4. Warmth and Redness: Could Your Joint Replacement Be Infected?
A common concern after knee replacement is that the operated knee feels warmer than the opposite knee.
Many patients assume that warmth automatically means infection.
Fortunately, that isn’t true.
Inflammation and increased blood flow are natural components of the healing process.
A replaced knee can remain warmer than the opposite knee for several months, and occasionally for a year or longer.
### What’s usually normal?
– Mild residual warmth around the knee
– Warmth that gradually decreases over time
– Mild swelling that fluctuates with activity
– An incision that is healed without drainage or spreading redness
### What are the warning signs of infection?
Potential signs of periprosthetic joint infection include:
– Increasing redness around the incision
– Redness spreading into surrounding skin
– New or worsening joint pain
– Increasing warmth and swelling
– Fever or chills
– Persistent or new wound drainage
– An incision that opens after initially healing
One particularly important point: **Not every joint replacement infection causes a fever.**
Some infections produce subtle symptoms, including persistent pain, stiffness, or swelling.
Others can develop suddenly after a previously successful recovery.
Because early diagnosis can significantly affect treatment options, suspected infection should be evaluated promptly.
New drainage from a surgical incision should always be reported to your surgeon.
**Bottom line:** Warmth alone doesn’t diagnose infection. New or progressive warmth, redness, pain, swelling, or drainage deserves medical attention.
## 5. Numbness Around Your Incision: Is It Nerve Damage?
Many patients notice an area of reduced skin sensation after hip or knee replacement.
This is particularly common around knee replacement incisions.
Small sensory nerve branches travel through the skin surrounding the knee. Some can be stretched or disrupted during surgery.
As a result, patients may notice:
– Numbness alongside the incision
– Tingling or altered skin sensation
– Small patches that feel different when touched
– Occasional sensitivity around the scar
These symptoms frequently improve with time, although some numbness may persist permanently.
Importantly, a stable patch of numbness around the incision does not mean the replacement itself is failing.
### What symptoms are concerning?
Contact your surgical team urgently if you develop:
– New or progressive weakness
– Sudden inability to lift your foot
– Rapidly worsening numbness
– Significant new loss of sensation or movement
These symptoms are different from the expected sensory changes surrounding a healing incision.
**Bottom line:** A small, stable numb patch around the incision is common. New weakness or progressive neurological symptoms require evaluation.
## 6. Sudden Difficulty Walking or Bearing Weight
Early after joint replacement, patients commonly experience muscle weakness, stiffness, and changes in their walking pattern.
These symptoms usually improve with recovery and rehabilitation.
But there’s an important difference between gradually rebuilding your strength and suddenly losing your ability to walk.
### What’s usually normal?
– Temporary limping during early recovery
– Muscle fatigue after increased activity
– Gradual improvement in walking distance
– Mild stiffness after prolonged sitting
### What symptoms are concerning?
A sudden major change in function may indicate a complication.
Examples include:
– Sudden inability to bear weight
– Severe pain following a fall
– A hip that appears visibly deformed
– New, repeated knee buckling
– Sudden loss of the ability to straighten or support the leg
Potential causes include fracture around the implant, hip dislocation, or injury to the structures supporting the joint.
**A sudden inability to bear weight, especially with severe pain or deformity, requires emergency assessment.**
Do not attempt to walk through severe new pain or force the joint to move.
**Bottom line:** Gradual weakness during recovery can be expected. Sudden major loss of function is not.
## 7. New Pain Months or Years After a Successful Joint Replacement
This may be the most important warning sign patients overlook.
Imagine you had a hip replacement three years ago.
Your recovery was excellent. You’ve been walking, exercising, traveling, and enjoying life without pain.
Then, seemingly out of nowhere, your hip starts hurting.
Maybe the pain develops gradually over several weeks. Maybe it comes with swelling or stiffness.
Should you be concerned?
**A previously well-functioning joint replacement that develops new, persistent, unexplained pain deserves evaluation.**
There are several potential explanations, including:
– Implant loosening
– Wear-related problems
– Fracture
– Tendon or muscle disorders
– Referred pain from the spine
– Late periprosthetic joint infection
### Can a joint replacement become infected years later?
Yes.
Although many infections develop around the time of surgery, bacteria can occasionally reach an artificial joint through the bloodstream months or years later.
These infections can sometimes develop without dramatic symptoms.
New pain doesn’t automatically indicate infection, but it shouldn’t be dismissed simply because the original surgery occurred years ago.
**Bottom line:** A joint replacement that worked well for years and suddenly develops persistent symptoms should be evaluated.
—
## How Do Orthopedic Surgeons Determine Whether a Joint Replacement Is Failing?
Patients often ask whether an X-ray can tell if their implant is failing.
X-rays are important, but they represent just one part of the evaluation.
When I evaluate a patient with a painful hip or knee replacement, the process usually involves several steps.
### Step 1: Understanding the symptoms
We start with the patient’s history.
Important questions include:
– When did the symptoms begin?
– Was there a fall or injury?
– Is the pain getting better or worse?
– Is it worse with activity or at rest?
– Have you experienced fever, redness, drainage, or swelling?
– Was the joint previously functioning well?
The timing and pattern of symptoms often provide valuable clues.
### Step 2: Physical examination
Next, we examine the joint.
We evaluate motion, stability, swelling, strength, tenderness, and the condition of the incision.
We also assess surrounding structures that could contribute to pain.
### Step 3: X-rays
X-rays can help identify:
– Changes in implant position
– Fractures around the replacement
– Certain signs of loosening
– Other mechanical abnormalities
However, normal X-rays don’t completely exclude infection or every form of implant-related complication.
### Step 4: Blood tests for inflammation
If infection is a concern, we often obtain:
**ESR (erythrocyte sedimentation rate)**
**CRP (C-reactive protein)**
These tests measure inflammation in the body.
Elevated results can increase concern for infection, but neither test is specific enough to diagnose an infected joint replacement by itself.
They also require careful interpretation following recent surgery because postoperative inflammation can elevate these markers.
### Step 5: Joint aspiration
If the history, examination, or testing raises concern for infection, we may recommend a joint aspiration.
This involves collecting fluid from around the replacement using a needle.
The fluid can be analyzed for:
– White blood cell count
– Percentage of neutrophils
– Bacterial cultures
– Additional infection markers when appropriate
This information helps determine whether infection may be present and guides further management.
Depending on the findings, additional imaging or specialized tests may be necessary.
**The most important message: Patients do not need to diagnose implant failure themselves. Recognizing a significant change and communicating it to their surgical team is the first step.**
—
## The 3 Questions Every Joint Replacement Patient Should Ask
If you’re recovering from hip or knee replacement and wondering whether a symptom is normal, I recommend starting with three questions.
### 1. Is this a new symptom?
Have you experienced this throughout recovery, or did it begin suddenly after a period of improvement?
### 2. Is the overall trend improving or worsening?
An uncomfortable day doesn’t necessarily indicate a complication.
But symptoms that become progressively worse deserve attention.
### 3. Is this affecting your ability to function?
Are you still able to walk and perform your usual activities?
Or has your ability to function suddenly deteriorated?
These questions aren’t diagnostic tests, and they cannot reliably exclude infection, blood clots, or mechanical complications. However, they can help you describe the problem clearly to your surgical team.
## Normal Recovery vs. Warning Signs: Quick Reference
| Often part of normal recovery | Symptoms requiring medical evaluation |
|—|—|
| Painless knee clicking | Painful clicking with new instability |
| Mild soreness after activity | Progressive or severe pain |
| Intermittent swelling | Sudden, significant swelling |
| Gradually decreasing warmth | Increasing redness, warmth, and pain |
| Stable numbness around incision | New weakness or progressive numbness |
| Gradual improvement in walking | Sudden inability to bear weight |
| Occasional stiffness | Persistent new pain after a successful recovery |
| Healing incision without drainage | New or persistent wound drainage |
**Important:** This table is a general guide, not a way to rule out complications. New or concerning symptoms should always be discussed with your healthcare team.
## Final Thoughts: Your Recovery Doesn’t Have to Be Perfect
One of the biggest misconceptions about joint replacement recovery is that every day should be better than the last.
That’s rarely how healing works.
Some days you feel great.
Other days you’re stiff, swollen, or sore.
The presence of an uncomfortable symptom doesn’t automatically mean your implant is failing.
But the opposite is equally important: **Not every serious complication follows a textbook pattern.**
If something feels significantly different, symptoms are worsening, or you’re concerned about your recovery, reach out to your surgeon.
You aren’t bothering your medical team by asking questions.
We would much rather evaluate a potential problem early than discover a serious complication after unnecessary delays.
The goal of joint replacement isn’t simply to place an implant.
It’s to help you return to a more comfortable, active, and confident life.
Understanding what to expect during recovery is an important part of achieving that goal.
—
## Watch Episode #67 of The Joint Replacement Podcast
**Is My Hip or Knee Replacement Failing? 7 Warning Signs vs. Normal Healing**
In this episode, Dr. Matthew Sloan explains which postoperative symptoms are common, which require medical attention, and how orthopedic surgeons evaluate potential complications after joint replacement.
Watch and subscribe on YouTube: [The Joint Replacement Podcast](https://www.youtube.com/@thejointreplacementpodcast)
Visit: https://www.thejointreplacementpodcast.com
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—
*Medical Disclaimer: This article is intended for educational purposes only and does not constitute individualized medical advice. Symptoms after joint replacement should be evaluated in the context of each patient’s medical history and examination. Contact your surgical team regarding new, persistent, or worsening symptoms. Severe pain with inability to bear weight, suspected joint dislocation, chest pain, or sudden shortness of breath may require emergency medical evaluation.*
**About the Author**
**Matthew Sloan, MD**, is a board-certified orthopedic surgeon and Director of Robotics for Orthopedics at Emerson Health in Concord, Massachusetts. He specializes in robotic-assisted hip and knee replacement, including anterior hip replacement and cementless knee replacement. He is the creator and host of *The Joint Replacement Podcast*, dedicated to helping patients understand hip and knee replacement and the surgeons who perform it.