A knee pain specialist works out where the pain is really coming from: the joint, the tendons and bursae around it, the nerves that carry its signal, or somewhere else, because the hip and the lower back both send pain to the knee. Then that source is treated. At the Padda Institute in St. Louis there is no referral needed, and most knee pain is treated without surgery.
Here is the fact that should change how every knee is worked up. In a study of 991 adults from Framingham, Massachusetts, aged 50 to 90 and picked at random, a meniscal tear showed up on MRI in up to 56 percent of the older men. Sixty-one percent of the people with a tear had no knee pain, aching or stiffness in the month before the scan. A torn meniscus is common furniture in a knee past 50. Finding one does not explain your pain.
Not always, and missing this is the most expensive mistake in knee care. Three sources outside the joint send pain to the knee:
A diagnostic block settles the question when the exam cannot. Numbing medicine is placed on the nerves of the knee under imaging. If the pain drops by most of the way for a few hours, the knee is the source. If it does not, we stop looking at the knee.
Front, around or behind the kneecap. Worse on stairs, squatting, or after sitting through a movie. That is the patellofemoral joint, where the kneecap rides in its groove. Weak hips and thighs let the kneecap track poorly, so the fix is often above the knee.
Inside of the knee. The most common place for arthritis, because the inside of the knee carries more of your weight with every step. A spot a few inches below the joint line, tender to a fingertip, is often the pes anserine bursa, which is treated very differently from arthritis.
Outside of the knee. Runners and cyclists feel the iliotibial band here. Older knees with outer pain may have arthritis or a worn outer meniscus.
Back of the knee. A fullness that gets tight when you straighten the leg is often a Baker’s cyst. The cyst is a symptom: extra fluid from a joint problem in front, pushed backward.
Catching or locking. A knee that truly locks and will not straighten until you wiggle it has something loose inside. That knee needs imaging soon.
Because the knee was not the whole problem. The new joint can be perfect on X-ray while the nervous system around it keeps firing. Two things drive most of it. The volume knob was already turned up before the operation, and surgery did not turn it down. Or a small nerve near the incision was injured, and it now fires on its own. Neither shows on a scan.
These knees can still be treated. Genicular nerve blocks and genicular radiofrequency ablation target the sensory nerves of the knee without touching the implant. Read more in persistent pain after knee replacement and how central sensitization is measured.
Both, and the second part gets left out. Extra weight adds load with every step, that part is mechanics. But fat is not a sack of sand. Belly fat in particular is an active organ. It releases inflammatory signals that reach the joint lining through the blood. High insulin keeps those signals switched on and wears down the cartilage cells’ ability to repair. That is metabolic inflammation, and it works on a knee whether or not the knee is carrying the weight.
The STEP 9 trial gives a sense of scale. It enrolled 407 adults with obesity and painful knee arthritis. Their average body mass index was 40, and 82 percent were women. Everyone got diet and activity counseling. Those also given weekly semaglutide lost 13.7 percent of their body weight, against 3.2 percent on placebo. Their knee pain score fell 41.7 points, against 27.5 on placebo. The drug maker funded the trial, and the people in it were heavier than most of our patients. Still, the knee answered to what happened in the rest of the body.
I spent years as a strict vegetarian, defending the low-fat guidelines that filled grocery carts with refined starch. I changed my mind when the physiology said to, and a knee is one of the places that physiology shows. The economics matter too. A desk job, a long commute, and a food supply built on cheap acellular carbohydrates are not personal failings. They are the conditions most of our patients live in. That is why knee care here includes your A1c, your fasting insulin, and a plan for food and strength, alongside anything we inject. Strong quadriceps and hip muscles take load off the joint surface. The cartilage itself is fed by movement, because it has no blood supply and drinks joint fluid each time it is squeezed. A knee that stops moving starves.
Find the generator. Exam first, then X-ray or ultrasound read against the exam, then a diagnostic block when the source is still in doubt.
Calm it. A well-placed steroid injection lowers inflammation and buys function for weeks to months. It is not free for people with diabetes: a single knee steroid shot raises blood sugar for days. See cortisone shot side effects in the knee. Gel shots (viscosupplementation) help some knees a little.
Quiet the nerves. When pain keeps coming back and the block proved the knee is the source, genicular nerve blocks lead to radiofrequency ablation of the sensory nerves. Our page on where knee arthritis pain comes from explains why cartilage itself cannot hurt.
Treat the joint itself. Our orthobiologic knee osteoarthritis treatment page lays out PRP, bone marrow concentrate and fat grade by grade. For a worn knee, an intra-articular orthobiologic injection treats the joint lining. When MRI shows the bone under the cartilage is inflamed, a subchondral injection treats the bone as well. At bone-on-bone, these buy time and cut the amount of pain medicine you need. That is a real goal, not a consolation prize.
Then the work that keeps it. Every procedure is a bridge. It lowers the pain enough to strengthen, lose weight, sleep and move. A bridge with nothing on the other side just leads back to the clinic.
Knee procedures are done with local anesthetic. No sedation is used, most patients drive themselves home, and normal activity resumes within two to four hours.
Some knees do. A knee that locks and will not straighten, a knee that gave way in a twist and swelled within hours, and a joint that has collapsed and fails every other treatment are all surgical questions. A knee replacement is the definitive operation for a finished joint, and for people who want it, it is a good one.
Clean-out surgery for a worn knee is a different story. In a Finnish trial of 146 adults aged 35 to 65 with a degenerative meniscal tear and no arthritis, trimming the torn meniscus did no better than a sham operation at one year. Before anyone trims a meniscus that may have torn quietly years ago, find out whether it is the source.
More on the knee from Dr. Padda on YouTube:
Yes. No referral is needed to book here. Some managed-care plans want one on file before they pay, so check your plan or read do you need a referral for pain management.
Not first. Because so many painless knees show tears and wear, an MRI ordered before an exam often finds something that is not the problem. An X-ray taken standing up shows arthritis better. MRI earns its place when the knee locks, gives way, or does not respond as expected.
For most people, no. Cartilage is fed by load and motion. Walking at a pace and distance your knee tolerates, with stronger thighs and hips doing their share, protects the joint. Pain that lasts into the next day means the dose was too high, not that walking is wrong.
Within hours. The numbing medicine works right away. You keep a pain diary that afternoon, doing the things that usually hurt. A large drop for the life of the medicine tells us the genicular nerves are carrying the pain.
Orthobiologic injections are not billed to insurance. HSA and FSA funds are generally eligible. Nerve blocks, ablation and steroid injections are billed as usual.
Bring any knee or hip X-rays, a list of injections you have had and how long each one lasted, and your medication list, including blood thinners. If a surgeon has offered a scope for a meniscal tear, bring that report too. Call us or request an appointment. See all conditions we treat.
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