PRP vs BMC for Ligament Healing

Published on Aug 3, 2022

I love writing about what I experience on a day-to-day basis. A patient recently wrote to me claiming that a prolotherapy physician had told him that PRP injections were clearly superior to Bone Marrow Concentrate for helping ligaments heal. Hence, I figured it was time for a formal deep dive to help patients understand the differences between these two and the current state of the art of the research. Let’s dig in.

What Is PRP and What Is BMC?

PRP stands for Platelet-Rich Plasma and BMC for Bone Marrow Concentrate. PRP has concentrated platelets in plasma and is believed to work by those platelets releasing growth factors which can help act as espresso shots for the local repair cells. BMC is when the stem cell containing fraction of bone marrow aspirate is concentrated. This is believed to work by mesenchymal stem cells acting as a general contractor for the repair response, also doling out growth factor espresso shots, and then in the end turning into the bricks and mortar needed for the repair job.

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The Research on PRP and Ligament Injuries

The vast majority of clinical research on the use of PRP to treat ligament injury focuses on use in surgical ligament grafts, which is regrettably not at all like injecting PRP into a damaged ligament. However, there are a handful of studies that show that partial Ulnar Collateral Ligament tears of the elbow have been successfully treated with PRP injection. These studies show good return-to-play results but are only case series with no randomized controlled trials in existence at the time of this writing (1-3). There is also one ACL case series (n=38) where low-dose LP- PRP was used to treat partial ACL tears in young patients with good results (7).

There are a few small case reports on the use of PRP injections to treat Medial Collateral Ligament injuries in the knee and Supraspinous Ligament injuries in the lumbar spine, but not enough research to draw conclusions.

The Research on BMC and Ligament Injuries

The clinical research on the use of BMC injection to treat ligament injury has a similar problem to the PRP literature in that it’s mostly been tested when used to enhance ligament reconstruction surgery. Hence, that application has little to do with precise injections into ligaments to help them heal without any surgery. However, almost all of the research on BMC injections that exists to date has been published by our research group and focuses on ACL complete non-retracted tears.

We have published 3 clinical studies on the use of BMC injected into ACL tears with both MRI and clinical follow-up. The first two studies were MRI imaging case series showing good imaging and clinical evidence of ACL healing and functional improvement (4,5). The third study is the mid-term analysis of a randomized controlled trial (RCT) versus exercise therapy which also showed excellent results (6). This RCT is now complete and is being readied for publication, with similar results.

What Can We Conclude from the Research about the Efficacy of PRP vs BMC Injections to Treat Ligament Injury?

Not much. PRP has been used to treat lesser partial ligament injuries in a few case series, but there is no higher level RCT research that conforms these findings. BMC has been used to treat higher-grade complete non-retracted ligament injuries with one higher-level RCT published by our group. However, there is no head-to-head trail for this clinical application in existence.

So was our prolotherapy physician correct? Not based on any existing clinical research.

Direct Clinical Experience with Both

In order to know how these two treatments compare, you would have needed to treat hundreds of patients with ligament injury with both technologies. I looked up the prolotherapy physician and sure enough, he only uses prolotherapy (injections to cause a brief healing reaction in ligaments) and PRP and doesn’t offer BMC. Hence, comparing these two would be impossible.

However, our clinic performs almost a thousand BMC injections a year and several thousand PRP injections, with a sizable percentage of these being into ligaments that have been damaged. Hence, over almost two decades, we have been able to directly compare the results of each technology in more than a thousand patients with ligament laxity or injury.

What have we observed? PRP can work well for partial ligament tears but generally underperforms in complete non-retracted (bigger) ligament tears. In addition, that’s ultra-high dose LP-PRP made in a clean-room lab, not the mid to low dose stuff you can make in a simple bedside centrifuge. So for a bigger ligament injury, we don’t use PRP.

Credit: Shutterstock

The Application Where this Becomes a Bigger Deal

If you’re injecting a damaged knee ACL, then trying ultra high-dose PRP is fine. The injection route is very safe and much less invasive than surgery, so if PRP doesn’t work and you need to switch to BMC, then no harm no foul. The only real downside is an extra cost for the patient.

However, if you’re pursuing a more novel injection approach where the stakes are higher, like our PICL fluoro and endoscopy-guided injection to treat an otherwise disabled craniocervical instability (CCI) patient who is considering a hugely invasive cervical fusion, then the goal is to perform the procedure as few times as possible. That’s because while the PICL procedure is clearly less invasive and has far fewer complications than fusion, it’s still only been performed to date around 800 times and is much more technically demanding than injecting the knee ACL.

The upshot? Was the prolotherapy doctor with no BMC experience correct? Not based on the peer-reviewed literature and our extensive clinical experience with both technologies. However, this answer was much longer than an email back to my patient, so that’s why I took a few hours to dig in deeper today.

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References:

(1) Hoffman JK, Protzman NM, Malhotra AD. Biologic augmentation of the ulnar collateral ligament in the elbow of a professional baseball pitcher. Case Rep Orthop. 2015;2015:130157.
(2) Dines JS, Wiliams PN, ElAttrache N, Conte S, Ahmad CS, et al. Platelet-rich plasma can be used to successfully treat elbow ulnar collateral ligament insufficency in high-level throwers. Am J Orthop. 2016;45(5):296–300.
(3) Deal JB, Smith E, Heard W, O’Brien MJ, Savoie FH. Platelet-rich plasma for primary treatment of partial ulnar collateral ligament tears: MRI correlation with results. Orthop J Sports Med. 2017;5(11):2325967117738238. doi: 10.1177/2325967117738238.

(4) Centeno CJ, Pitts J, Al-Sayegh H, Freeman MD. Anterior cruciate ligament tears treated with percutaneous injection of autologous bone marrow nucleated cells: a case series. J Pain Res. 2015;8:437–447. https://www.ncbi.nlm.nih.gov/pubmed/26261424

(5) Centeno C, Markle J, Dodson E, et al. Symptomatic anterior cruciate ligament tears treated with percutaneous injection of autologous bone marrow concentrate and platelet products: a non-controlled registry study. J Transl Med. 2018;16(1):246. https://www.ncbi.nlm.nih.gov/pubmed/30176875

(6) Centeno C, Lucas M, Stemoer I, Dodson E. Image-Guided Injection of Anterior Cruciate Ligament Tears with Autologous Bone Marrow Concentrate and Platelets: Midterm Analysis from a Randomized Controlled Trial. Bio Ortho J Vol 3(1):e29–e39; October 5, 2021.

(7) Koch M, Mayr F, Achenbach L, et al. Partial Anterior Cruciate Ligament Ruptures: Advantages by Intraligament Autologous Conditioned Plasma Injection and Healing Response Technique-Midterm Outcome Evaluation. Biomed Res Int. 2018;2018:3204869. Published 2018 Jul 25. doi:10.1155/2018/3204869