Platelet-rich Plasma May Ben­e­fit Early Knee OA

Wellness Update - - What Doctors Know And Your Should, Too! - Dr. Mat­te­son agrees that PRP pro­ce­dures need to be stan­dard­ized. "There is a whole con­glom­er­a­tion of stuff out there," Dr. Mat­te­son says, "and we need to sort out what may or may not have a bi­o­log­i­cal ef­fect." -This in­for­ma­tion pro­vided courtesy of Weill

Platelet-rich plasma (PRP), a ther­apy used to help heal sur­gi­cal wounds and ten­don in­juries, may also re­lieve symp­toms of early knee os­teoarthri­tis (OA), ac­cord­ing to a new study out of the Hos­pi­tal for Spe­cial Surgery (HSS) in New York. Re­searchers there say pa­tients with knee OA re­ported sig­nif­i­cantly im­proved pain and func­tion for 12 months af­ter a sin­gle PRP in­jec­tion. The find­ings, pub­lished on­line in Clin­i­cal Jour­nal of Sports Medicine, also sug­gest that PRP may slow joint dam­age if ad­min­is­tered early in the course of the dis­ease. "The re­sults are very ex­cit­ing," says Brian Halpern, MD, chief of the Pri­mary Care Sports Medicine Ser­vice at HSS and lead author of the study. "This sug­gests that PRP may have the po­ten­tial not only to re­lieve symp­toms but also to de­lay pro­gres­sion of OA, al­though we don't know if that will con­tinue year af­ter year." Dr. Halpern is also a clin­i­cal as­so­ciate pro­fes­sor at Weill Cor­nell Med­i­cal Col­lege in New York. PRP is a prepa­ra­tion of platelets de­rived from a per­son's own blood. It's ob­tained by spin­ning a small amount of blood in a cen­trifuge to sep­a­rate the platelets from red and white blood cells. The con­cen­trated platelets are then in­jected into prob­lem ar­eas where they are thought to re­lease growth fac­tors and stim­u­late the heal­ing process. In the HSS study, re­searchers in­jected 22 pa­tients with 6 milliliters of PRP and fol­lowed them for one year. All par­tic­i­pants had di­ag­nosed knee OA and had arthri­tis-re­lated pain for an aver­age of 14 months. The pa­tients were clin­i­cally eval­u­ated at base­line and pe­ri­od­i­cally through­out the year for knee pain, func­tion, stiff­ness and the abil­ity to per­form tasks of daily liv­ing, such as climb­ing stairs. Study par­tic­i­pants also un­der­went mag­netic res­o­nance imag­ing (MRI) to eval­u­ate joint car­ti­lage at base­line and at one year – some­thing not done in pre­vi­ous PRP stud­ies. Al­though ques­tion­naires used in the study – the vis­ual ana­log scale (VAS) and Western On­tario and McMaster Uni­ver­si­ties Arthri­tis In­dex (WO­MAC) – are val­i­dated tools rou­tinely used to as­sess pain and func­tion in peo­ple with OA, they are sub­jec­tive. An MRI, on the other hand pro­vides an ob­jec­tive pic­ture of changes in the joint. Seventeen pa­tients com­pleted the study and full MRI data was avail­able for 15. For the ma­jor­ity of pa­tients, clin­i­cal out­comes were en­cour­ag­ing. On the VAS pain scale, pain was re­duced 56.2 per­cent at 6 months and nearly 60 per­cent at one year. WO­MAC scores showed sim­i­lar re­duc­tions in pain and stiff­ness. Ac­tiv­i­ties of daily liv­ing (ADL) scores also im­proved sig­nif­i­cantly: 46.8 per­cent at 6 months and 55.7 per­cent at one year. What's more, most study par­tic­i­pants showed no fur­ther car­ti­lage loss a year af­ter the PRP in­jec­tion. Pre­vi­ous stud­ies have found that peo­ple with knee OA tend to lose around 5 per­cent of car­ti­lage per year. Dr. Halpern stresses that the pos­i­tive re­sults oc­curred in peo­ple with early OA. "You're not go­ing to be able to do a lot in the re­gen­er­a­tive sense for peo­ple with bone-on-bone arthri­tis. By then, the horse is al­ready out of the barn," he says. "But in the ear­lier stages, you can im­prove symp­toms and the en­vi­ron­men­tal mi­lieu enough to de­lay or maybe even pre­vent knee re­place­ment. But that's a long way off and we need to look at a lot more num­bers [be­fore we can say that with cer­tainty]." Still, Dr. Halpern says the study re­sults have prompted HSS to cre­ate a reg­istry that will track fu­ture os­teoarthri­tis pa­tients over time. Re­searchers will be able to com­pare out­comes for var­i­ous OA treat­ments, such as ex­er­cise, weight con­trol, brac­ing and hyaluronic acid in­jec­tions as well as PRP. And for the first time, imag­ing tests will be used to de­tect changes in joint car­ti­lage.

It's hoped that the HSS data will help an­swer some of the many ques­tions that arise as PRP treat­ments be­come more com­mon. "Many more folks are do­ing it now, es­pe­cially sports medicine or­thopaedists, and they are learn­ing more about why it can and can't work," says Dr. Halpern, not­ing that he has in­jected more than 400 pa­tients with PRP over the last five years and all had out­comes con­sis­tent with the study re­sults. "One ex­am­ple is that it ap­pears the platelet con­cen­tra­tion has an ef­fect on ef­fi­cacy, but we don't know what the op­ti­mum [level] is right now. That's an­other thing that has to be ex­plored,” he says. “By def­i­ni­tion, PRP for­mu­la­tions have to be two to five times greater than the platelet con­cen­tra­tion in the blood. But it seems that if platelet con­cen­tra­tion gets as high as eight times greater, it can ac­tu­ally have a dele­te­ri­ous ef­fect." Dr. Halpern stresses that PRP is not a panacea. "It cer­tainly won't help ev­ery­body with ev­ery­thing," he notes. "This is an evolv­ing field, and we need to learn much more." Eric L. Mat­te­son, MD, chair of rheuma­tol­ogy at the Mayo Clinic in Rochester, Min­nesota, agrees that PRP needs more study. "The real is­sue from a bi­o­log­i­cal stand­point is whether PRP con­tains fac­tors that can some­how stim­u­late car­ti­lage and in so do­ing im­prove arthri­tis. There has to be some demon­stra­tion of ac­tual ef­fect. If there is im­prove­ment in car­ti­lage, we should be able to see it, but this study didn't show that,” says Dr. Mat­te­son. “And if MRI didn't show an im­prove­ment, then what ac­counts for the de­crease in pain? Per­haps the placebo ef­fect. We re­ally have no idea. We need stud­ies that show the bi­o­log­i­cal plau­si­bil­ity of this treat­ment." Or­thopaedic sur­geon Ja­son Scopp, MD, di­rec­tor of the Joint Preser­va­tion Cen­ter at Penin­sula Or­thopaedic As­so­ciates in Sal­is­bury, Md., says that in ad­di­tion to fail­ing to show bi­o­log­i­cal plau­si­bil­ity, the HSS study has other short­com­ings. "This is a very small sam­ple size, which means the study is un­der­pow­ered, and there is no con­trol group for com­par­i­son. Other stud­ies of PRP have en­rolled more pa­tients, are bet­ter pow­ered and com­pare PRP to vis­co­sup­ple­men­ta­tion [hyaluronic acid in­jec­tions]," he notes. Still, de­spite what he sees as the lim­i­ta­tions of this study, Dr. Scopp is a fan of PRP. "PRP is a great prod­uct, and sev­eral stud­ies have shown it to be su­pe­rior to cor­ti­sone and even vis­co­sup­ple­men­ta­tion, but there is still no con­sen­sus on the best prepa­ra­tion, best vol­ume of in­jec­tions and num­ber of in­jec­tions," he says.

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