Knee arthritis gel injection has become a common treatment. The gel is called hyaluronic acid and provides most patients with 6 months to a year of relief. However, when compared head to head, platelet rich plasma (PRP) injections tend to outperform knee gel shots. Now a recent animal study shows PRP is also better at healing cartilage.
The concept behind a knee arthritis gel injection is to replace the natural lubricant which can be lost in arthritis. In addition, the gel likely also improves the nasty environment of bad chemicals commonly seen in arthritic joints. PRP is a different animal altogether, being a mix of concentrated platelets from the patient’s own blood. Both of these knee arthritis shots have been shown to help pain and improve function, but PRP is a newer therapy.
Past studies on real patients with knee arthritis have shown that PRP is better at pain relief for longer than HA. However, to my knowledge, no study has ever compared head to head their abilities to heal a cartilage defect. In this study, a knee cartilage defect was artificially created in 30 rabbits. 10 rabbits in each group received either HA, PRP, or saline injections weekly for 3 weeks. When the cartilage lesions were later examined at 6 and 12 weeks after the injury with micro CT scans, microscope histology exam, and measuring the levels of bad chemicals in the joint-the PRP treated joints showed better cartilage/bone healing and less inflammation than the HA treated joints.
Perhaps the most interesting tweak in this study is the concentration of the PRP, which was about 7 times the baseline amount of platelets found in the blood. Most commercial bedside centrifuges being used by physicians today only concentrate platelets from 2-5X over baseline, or less than the concentration that was used here. Our own internal lab studies have shown much better results when the platelets are concentrated to higher amounts, which is how our super-concentrated version of PRP was conceived.
The upshot? PRP seems to be developing a track record of besting knee gel shots for knee arthritis. While both of these injection types seem to help knee arthritis patients, for mild or moderate arthritis, PRP seems to be the best choice. In addition, as suspected, PRP seems to have a better regenerative effect on cartilage.