Platelet-Rich Plasma Injections: Need-to-know information

Pre-injection considerations:


1. There are numerous different PRP concentrating systems available, all of which can make PRP from your dog’s own blood.    At Colorado Canine Orthopedics and Rehab we currently use two different systems routinely, they are the Autologous Conditioned Plasma (ACP) system or the Angel system. We are also investigating a third system, Autologous Protein Solution (APS), as part of two research projects. Given the success we have had with APS, we could use this for a routine patient if desired by the client.

​2. Differences among systems: 

   a. ACP

  • Volume of blood – this system uses just 15 milliliters (mls) of blood

  • Volume of PRP made – typically we acquire just about 2 mls of ACP. This is enough for 1 or 2 injections (eg 2 joints) at most. There is rarely sufficient volume to inject more than 2 joints and there is rarely enough volume left over to save (freeze) for future use.

  • Cost – Approximately $265 for one injection using this system.

  • Platelet-concentration – ACP provides a low platelet concentration. Intuitively this may make you think that it less optimal. However, this is unclear (see next).

  • Efficacy – ACP is the single most thoroughly studied canine PRP. There are 3 studies in dogs that suggest that it is efficacious with intra-articular injection.

  • Use – Dr. Franklin usually opts for ACP in patients in which only a small volume of blood and PRP, such as a small dog in which we are going to inject one joint. ​

    b. ​ Angel 

  • Volume of blood – We can use as little as 35 mls of blood or up to 500 mls of blood with this system. 

  • Volume of PRP made – typically we can acquire 10 mls or more of PRP.  This is commonly enough to inject multiple joint and have adequate volume left over to store (freeze) PRP for future injections. 

  • Cost – Approximately $465 for one preparation.  In most cases we can store extra PRP for subsequent injection. Those subsequent injections are then much less expensive because the owner does not have to pay for the PRP preparation, only the sedation and injection.   

  • Platelet-concentration – Angel allows the preparation of a substantially higher platelet concentration. Intuitively this may make you think that it is superior to ACP, but this is unclear (see next).

  • Efficacy – Dr. Franklin has done numerous studies evaluating different characteristics of Angel PRP. Although the characteristics of the PRP are theoretically very desirable, we have yet to complete a study showing that its use provides better results than ACP when injected into dog joints. 

  • Use –Dr. Franklin usually opts for using Angel (rather than ACP) when treating either a large dog, multiple joints in a dog, and/or when repeat injection is considered possible and having frozen stored sample is appealing.

3. Patient Preparation 

  • Virtually all patients are sedated, not anesthetized, for their PRP injections. Please refrain from feeding your dog breakfast the morning of their injection. Patients will go home the same day as their injection. Please note that due to sedation, patients may be slightly groggy for a few hours afterwards.

  • Patients will have hair clipped under the neck for blood collection, on their forearm or foreleg for catheter placement, and at the location of the injection (eg over the joint of interest).

Post-injection considerations:


  • Your dog may resume eating and drinking as soon as your dog seems adequately awake to eat and drink.


  • Most dogs are uncomfortable following joint injections for 24-48 hours. Please make sure you have a pain medication available, such as a canine specific non-steroid anti-inflammatory, to give to your dog for 48 hours afterwards.  If you do not have a pain medication please ask our staff at the time you are checking out.


  • If your dog remains more uncomfortable for 96 hours following injection please contact a veterinarian. This would raise concern for the possibility of an infection in the joint. The chance of this complication is very low, far less than 1%, but is not something that we want to leave untreated if it occurs.


  • Exercise: Your dog can resume exercise after a joint injection. In general, we advise that exercise be consistent with their pre-injection routine as soon as they are ready (for example, after 48 hours after the initial discomfort of the injection has passed). Dramatic increases in exercise beyond a typical daily routine should be avoided to avoid making the dog dramatically more sore and hindering our ability to determine whether the injections were beneficial.


  • Timeline for recognizing benefit of injections: Dogs will rarely show demonstrable benefit in less than 2 weeks following a PRP joint injection thus we have to wait at least 2 weeks before drawing conclusions regarding benefit.  Most dogs that will show benefit will do so by 6 weeks. Therefore, if a dog has not appeared to benefit by 6 weeks following injection, that dog may not respond at all. However, the optimal protocol is not yet clearly established (see next). 


  • Repeat injections: There is no clearly defined (ie optimal) injection protocol with regard to the number of injections or frequency of injections. Dr. Franklin typically offers owners 2 protocols (though more are possible): 3 injections each spaced 1 month apart. This protocol offers the benefit of repeat delivery of the anabolic growth factors in the PRP, but also allows a reasonable time frame in between for owners to try and gauge whether there has been some benefit of the injection(s). Note that Dr. Franklin does offer use of frozen/thawed injections. He has done research showing the anabolic growth factor concentrations in such frozen aliquots of Angel PRP remain very high. However, we do not know if frozen injections are equally efficacious as fresh injections. The second protocol to choose from is one in which a single injection is performed, response evaluated by the owner, and an injection repeated when benefit (if seen) wanes. Some doctors, veterinarians, and owners claim benefits up to a year. The objective research suggests a maximal benefit of intra-articular injections in dogs to last up to 6 months. 

Evidence/Resources: The following studies can be provided to owners upon request. 

  1. Franklin SP. A Pilot Clinical Study Assessing Treatment of Canine Hip Dysplasia using Autologous Protein Solution. Frontiers in Veterinary Science 2019; 6:243 doi.org/10.3389/fvets.2019.00243

  2. Franklin SP, Birdwhistell KE. Assessment of Canine Autologous Conditioned Plasma™ Cellular and Transforming Growth Factor-β1 Content. Frontiers in Veterinary Science. 2018;11(5):105. doi: 10.3389/fvets.2018.00105

  3. Ludwig HC, Brainard BM, Birdwhistell KE, Franklin SP. Use of a cyclooxygenase-2 inhibitor does not inhibit platelet activation or growth factor release from platelet-rich plasma. American Journal of Sports Medicine. 2017;45(14):3351-3357. doi: 10.1177/0363546517730578

  4. Birdwhistell KE, Karumbaiah L, Franklin SP. Sustained release of transforming growth factor-β1 from platelet-rich chondroitin sulfate glycosaminoglycan gels. Journal of Knee Surgery. 2017. doi: 10.1055/s-0037-1603801.

  5. Franklin SP, Burke E, Holmes SP. The effect of platelet-rich plasma on osseous healing in dogs undergoing high tibial osteotomy. PLoS One. 2017; May 16;12(5):e0177597. doi: 10.1371/journal.pone.0177597.

  6. Franklin SP, Birdwhistell KE, Strelchik A, Garner BC, and Brainard B. Influence of Cellular Composition and Exogenous Activation on Growth Factor and Cytokine Concentrations in Canine Platelet-Rich Plasmas.  Frontiers in Veterinary Science. April 5, 2017. https://doi.org/10.3389/fvets.2017.00040

  7. Birdwhistell KE, Basinger RW, Hayes BR, Norton NA, Hurley DJ, Franklin SP. Validation of commercial ELISAS for quantifying anabolic growth factors and cytokines in canine ACD-A anticoagulated plasma. Journal of Veterinary Diagnostic Investigation. 2017 Mar;29(2):143-147 doi: 10.1177/1040638717690186.

  8. Franklin SP, Garner BC, and Cook JL. Characteristics of canine platelet-rich plasma prepared with five commercially available systems. American Journal of Veterinary Research, 2015; 76:822–827. 

  9. Franklin SP and Cook JL. Prospective trial of autologous conditioned plasma versus hyaluronan plus corticosteroid for elbow osteoarthritis in dogs. Canadian Veterinary Journal, 2013;54(9):881-884. 


If you have any questions please do not hesitate to contact Colorado Canine Orthopedics and Rehab at 719-264-6666.