Platelet Injections for a Worn Knee, Graded Against the Hype

What this page can and cannot tell you about platelets

It cannot tell you whether PRP works for knee arthritis. Gale cites only sources it has verified, and the platelet-specific trials are not among the sources behind this page — so any verdict here, favourable or damning, would be a sentence with nothing beneath it. That gap is worth stating plainly rather than papering over with confident-sounding prose.

The trial-by-trial reading exists elsewhere. The PRP RCT summary takes on the platelet literature directly, does prp work for tendon injuries handles the tendon version of the question, and prolotherapy evidence covers the older cousin. Each is a different body of trials, and none of them substitutes for the others.

What this page does instead may be the more useful thing anyway. A decision about an injection is never a decision about the injection alone — it is a decision about what to do with the next six months, and the rest of that menu has been measured with some care.

You cannot judge whether an untested option is worth it until you know what the tested options are worth.

What does exercise actually do for a knee?

It reduces pain and improves function, and the effect outlasts the appointments. A Cochrane review of land-based therapeutic exercise for knee osteoarthritis found short-term benefit in both pain and physical function, with the improvement sustained for two to six months after the formal treatment ended 1Ref 1Fransen M, McConnell S, Harmer AR, et al. (2015).Exercise for osteoarthritis of the knee.Land-based therapeutic exercise provides short-term benefit in reducing knee pain and improving physical function in knee osteoarthritis, sustained for two to six months after formal treatment ends — the article's claim that the benefit of exercise outlasts the appointments.. That last clause is the one people skip, and it is the interesting one.

The distinction matters commercially as much as clinically. An injection is a thing done to you on a Tuesday. Exercise is a capacity you build and then keep for a while afterwards 1Ref 1Fransen M, McConnell S, Harmer AR, et al. (2015).Exercise for osteoarthritis of the knee.Land-based therapeutic exercise provides short-term benefit in reducing knee pain and improving physical function in knee osteoarthritis, sustained for two to six months after formal treatment ends — the article's claim that the benefit of exercise outlasts the appointments.. Those are different kinds of asset, and there is no reason to price them the same way.

It is also the least popular finding in knee medicine. Exercise asks the patient to do the work, it is dull, and weeks pass before anything shifts. None of that is an argument against it. It is an explanation of why a needle is easier to sell.

The largest documented effect here involves no needle

It is losing weight while exercising, in people carrying extra weight. The IDEA trial randomized overweight and obese adults with knee osteoarthritis and found that intensive diet-induced weight loss combined with exercise produced greater reductions in pain and in inflammation, and better function, than exercise alone — and that the combination reduced the compressive load going through the knee 2Ref 2Messier SP, Mihalko SL, Legault C, et al. (IDEA) (2013).Effects of Intensive Diet and Exercise on Knee Joint Loads, Inflammation, and Clinical Outcomes Among Overweight and Obese Adults With Knee Osteoarthritis: The IDEA Randomized Clinical Trial.In overweight and obese adults with knee osteoarthritis, intensive diet-induced weight loss combined with exercise produced greater reductions in pain and inflammation and better function than exercise alone, and reduced knee compressive loads — the article's account of the largest measured effect among its sources, and its scoping of that finding to the population studied..

Three separate things moved in that trial, and they are worth separating. Pain fell. Inflammation fell. And the mechanical load through the joint fell 2Ref 2Messier SP, Mihalko SL, Legault C, et al. (IDEA) (2013).Effects of Intensive Diet and Exercise on Knee Joint Loads, Inflammation, and Clinical Outcomes Among Overweight and Obese Adults With Knee Osteoarthritis: The IDEA Randomized Clinical Trial.In overweight and obese adults with knee osteoarthritis, intensive diet-induced weight loss combined with exercise produced greater reductions in pain and inflammation and better function than exercise alone, and reduced knee compressive loads — the article's account of the largest measured effect among its sources, and its scoping of that finding to the population studied.. An injection, whatever else it may do, does not change what the knee carries with every step.

This is the finding most likely to land badly, and it deserves care rather than a lecture. Weight is not a moral fact. The advice to lose it is handed out carelessly and often cruelly. And plenty of people with knee arthritis are not carrying extra weight at all — for them, this trial simply does not apply. What it establishes is narrower and more respectful than the way the advice usually arrives: in the specific group it studied, adding weight loss to exercise did more than exercise alone 2Ref 2Messier SP, Mihalko SL, Legault C, et al. (IDEA) (2013).Effects of Intensive Diet and Exercise on Knee Joint Loads, Inflammation, and Clinical Outcomes Among Overweight and Obese Adults With Knee Osteoarthritis: The IDEA Randomized Clinical Trial.In overweight and obese adults with knee osteoarthritis, intensive diet-induced weight loss combined with exercise produced greater reductions in pain and inflammation and better function than exercise alone, and reduced knee compressive loads — the article's account of the largest measured effect among its sources, and its scoping of that finding to the population studied., and it did so by changing the physics rather than the perception.

What do the anti-inflammatories do?

The topical ones do more than their reputation suggests. A Cochrane review found that topical diclofenac and topical ketoprofen give good levels of pain relief in knee osteoarthritis, with minimal systemic adverse effects — the basis for reaching for them before oral anti-inflammatories, particularly in older adults 3Ref 3Derry S, Conaghan P, Da Silva JAP, Wiffen PJ, Moore RA (2016).Topical NSAIDs for chronic musculoskeletal pain in adults.Topical diclofenac and ketoprofen give good levels of pain relief in knee osteoarthritis with minimal systemic adverse effects, supporting their use before oral NSAIDs and especially in older adults — the article's claim that the cheap, low-risk end of the menu is better graded than its reputation suggests.. A gel is nobody's idea of a serious treatment. The evidence disagrees.

The phrase minimal systemic adverse effects is doing real work in that sentence. A topical is preferred over a pill in older adults not because it is gentler in spirit, but because the drug largely stays where it is put instead of circulating past a stomach and a pair of kidneys 3Ref 3Derry S, Conaghan P, Da Silva JAP, Wiffen PJ, Moore RA (2016).Topical NSAIDs for chronic musculoskeletal pain in adults.Topical diclofenac and ketoprofen give good levels of pain relief in knee osteoarthritis with minimal systemic adverse effects, supporting their use before oral NSAIDs and especially in older adults — the article's claim that the cheap, low-risk end of the menu is better graded than its reputation suggests..

Which makes an unglamorous point about sequence. A person weighing a cash-pay injection has frequently not yet worked through the cheap, well-graded, low-risk end of the menu. That is not a failure of the person. It is usually a failure of the fifteen-minute appointment in which the menu was supposed to be explained.

What does repeated cortisone do?

Less than hoped, and possibly worse than nothing. Adults with knee osteoarthritis were randomized to an intra-articular triamcinolone injection or to saline, every twelve weeks for two years. At the end, the steroid group's pain was no better than the saline group's, and the steroid group had lost more cartilage volume 4Ref 4McAlindon TE, LaValley MP, Harvey WF, et al. (2017).Effect of Intra-articular Triamcinolone vs Saline on Knee Cartilage Volume and Pain in Patients With Knee Osteoarthritis: A Randomized Clinical Trial.Repeated intra-articular triamcinolone every 12 weeks for two years did not improve knee osteoarthritis pain versus saline and was associated with greater cartilage volume loss — the article's account of what the injection already on the menu achieves against a saline comparator, scoped to repeated injections rather than a single one..

Notice what the comparator was: saline. Not nothing, and not a waiting list — a needle, an appointment, a clinician's attention, and salt water. The saline group did as well on pain 4Ref 4McAlindon TE, LaValley MP, Harvey WF, et al. (2017).Effect of Intra-articular Triamcinolone vs Saline on Knee Cartilage Volume and Pain in Patients With Knee Osteoarthritis: A Randomized Clinical Trial.Repeated intra-articular triamcinolone every 12 weeks for two years did not improve knee osteoarthritis pain versus saline and was associated with greater cartilage volume loss — the article's account of what the injection already on the menu achieves against a saline comparator, scoped to repeated injections rather than a single one.. Everything a person feels after an injection that is not the drug itself, the saline group got too.

Two years of injections every twelve weeks produced no pain advantage over saline, and more cartilage volume loss 4Ref 4McAlindon TE, LaValley MP, Harvey WF, et al. (2017).Effect of Intra-articular Triamcinolone vs Saline on Knee Cartilage Volume and Pain in Patients With Knee Osteoarthritis: A Randomized Clinical Trial.Repeated intra-articular triamcinolone every 12 weeks for two years did not improve knee osteoarthritis pain versus saline and was associated with greater cartilage volume loss — the article's account of what the injection already on the menu achieves against a saline comparator, scoped to repeated injections rather than a single one.. This is the trial that turns repeat-injection limits into a real clinical question rather than a bureaucratic one, and it is the one worth having in mind when a knee is offered another shot.

It is also, and this matters, a trial about repeated injections across two years. It is not evidence that a single cortisone shot at a well-chosen moment is a mistake.

What does surgery do for a worn knee with a torn meniscus?

Not more than physical therapy, in the population that was tested. The METEOR trial randomized people aged forty-five and over who had a meniscal tear alongside mild-to-moderate knee osteoarthritis to arthroscopic partial meniscectomy plus physical therapy, or to structured physical therapy alone. At six and twelve months, the surgery group had not improved more 5Ref 5Katz JN, Brophy RH, Chaisson CE, et al. (METEOR) (2013).Surgery versus Physical Therapy for a Meniscal Tear and Osteoarthritis.In patients aged 45 and over with a meniscal tear plus mild-to-moderate knee osteoarthritis, arthroscopic partial meniscectomy plus physical therapy gave no greater functional improvement at 6-12 months than structured physical therapy alone, and about 30 percent of the physical-therapy group crossed over to surgery — the article's evidence that a therapy-first sequence keeps the operation available rather than ruling it out..

And now the number that keeps this page honest: about 30 percent of the physical-therapy group crossed over and had the surgery anyway 5Ref 5Katz JN, Brophy RH, Chaisson CE, et al. (METEOR) (2013).Surgery versus Physical Therapy for a Meniscal Tear and Osteoarthritis.In patients aged 45 and over with a meniscal tear plus mild-to-moderate knee osteoarthritis, arthroscopic partial meniscectomy plus physical therapy gave no greater functional improvement at 6-12 months than structured physical therapy alone, and about 30 percent of the physical-therapy group crossed over to surgery — the article's evidence that a therapy-first sequence keeps the operation available rather than ruling it out..

That number is not a footnote. It is the entire shape of the recommendation. Therapy first does not mean therapy only, and it is not a door closing. It means beginning with the option that carries the better risk profile while keeping the operation available for the roughly one in three who turn out to need it. Nearly a third of the people who started with therapy ended up in an operating room, and the trial still found the strategy sound 5Ref 5Katz JN, Brophy RH, Chaisson CE, et al. (METEOR) (2013).Surgery versus Physical Therapy for a Meniscal Tear and Osteoarthritis.In patients aged 45 and over with a meniscal tear plus mild-to-moderate knee osteoarthritis, arthroscopic partial meniscectomy plus physical therapy gave no greater functional improvement at 6-12 months than structured physical therapy alone, and about 30 percent of the physical-therapy group crossed over to surgery — the article's evidence that a therapy-first sequence keeps the operation available rather than ruling it out..

A sequence of care is not a queue you have to survive. It is an order of attempts, with every option still open. Nothing here argues against an operation for a knee that needs one. What stage the joint has reached matters, and the stages of knee osteoarthritis are their own subject; so is whether arthroscopy for knee arthritis helps at all, and so is knee replacement benefit for a joint that has travelled past this conversation entirely. Each is a separate question with a separate literature, and a surgeon who has examined the knee is the person to answer them.

How would you know whether any of it worked?

By measuring the knee the way the trials measure it. The KOOS — the Knee Injury and Osteoarthritis Outcome Score — is a validated questionnaire a person fills in themselves, with five separate subscales: pain, symptoms, daily activities, sport and recreation, and knee-related quality of life 6Ref 6Roos EM, Roos HP, Lohmander LS, Ekdahl C, Beynnon BD (1998).Knee Injury and Osteoarthritis Outcome Score (KOOS)—Development of a Self-Administered Outcome Measure.The KOOS is a validated self-administered patient-reported outcome with five subscales — pain, symptoms, activities of daily living, sport and recreation, and knee-related quality of life — the basis for the article's lesson on asking which scale an improvement figure refers to.. Five subscales, because a knee can improve on one and not budge on another.

A patient-reported outcome is a score that comes from the person rather than from the scan — what you can do and how much it hurts, rather than what the cartilage looks like. The KOOS is one of these, and its structure is a lesson in itself 6Ref 6Roos EM, Roos HP, Lohmander LS, Ekdahl C, Beynnon BD (1998).Knee Injury and Osteoarthritis Outcome Score (KOOS)—Development of a Self-Administered Outcome Measure.The KOOS is a validated self-administered patient-reported outcome with five subscales — pain, symptoms, activities of daily living, sport and recreation, and knee-related quality of life — the basis for the article's lesson on asking which scale an improvement figure refers to.. A treatment that moves the sport subscale and leaves daily activities untouched has done something, but perhaps not the something you were buying.

So when a clinic quotes an improvement figure, three questions are worth asking. Improvement on which scale? Compared with what — a sham, a saline arm, or nothing? And is the change big enough that a person would notice it in an ordinary day, rather than merely big enough to reach statistical significance?

Those three questions are what this whole page has been for. They are also the questions to carry into the platelet conversation, because they are the ones that will either be answered honestly or not answered at all.