By Andrea L. Looney, DVM, DACVAA, DACVSMR, CCR
Massachusetts Veterinary Referral Hospital
A few years ago, we initiated a study on laser therapy, (now known as photobiomodulation, or PBM for short) to treat elbow degenerative joint disease (or DJD) following years of unsuccessful elbow osteoarthritis noninvasive, surgical, or arthroscopic treatment. We had seemingly hit a wall, as nothing we did seemed to stave off further degeneration or chronic pain.
At the time, PBM seemed to be a lot of self-marketing. There were many companies on the market, veterinarians attempting to decide between class III and IV, debates on what and when to treat, doses, duration of treatments, and more. Eventually, Companion Animal Health emerged as a leader because of the education and research they brought to the industry. We were fortunate to begin a study that utilized much of the evidence, equipment, and cutting-edge technology that the leaders in PBM were examining at the time.
Our initial PBM lower fluences did not result in adequate responses in owner perceived lameness and functional daily activities. However, evidence from the human musculoskeletal PBM literature, support from Companion’s research team and network of individuals heavily engaged in PBM therapy, and success in treating more neurogenic injury/chronic pain using higher fluences/power/penetration ALL suggested that we attempt to treat elbow synovitis/oa much like neurogenic pain- with higher fluences of light. Our study was initiated shortly thereafter.
In the initial phase/first week of the study, we had several patients in both the placebo and treatment group who improved drastically in a couple of the CPBI activity categories- namely rising movement and overall mobility. However, by the third week onward (halfway through the entire treatment period of six to seven weeks), it was clear that one group continued to improve in many of the functional activities and the owner’s perception of “lameness,” while the other group either remained static or declined. One goal of the study was to reduce the need for oral anti-inflammatories using PBM, so a key objective outcome was the reduced need for non-steroidal anti-inflammatory as the treatments progressed in the PBM group.
The study design supported the idea that treating the cranio and caudomedial aspects of the elbow joint was key to the alleviation of soft tissue and nerve elbow pain. As the disease becomes chronic, treatment of the triceps, biceps, and forearm extensors (especially trigger points within these muscle groups) can also greatly improve outcome.
With DJD so affected by environmental changes (humidity, pressure), concussive disease (step and stair necessity), and weight changes (forelimbs carrying more of the total weight distribution), utilizing the higher dose settings to treat elbow OA makes one thing clear: The frequency of continued ongoing treatments will vary. Many dogs will require more frequent, focused joint treatments weekly or every other week during the humid seasons of New England and more frequent referred pain (muscle group and compensatory axial tenseness) treatment in colder months. Many dogs who struggle with obesity, concurrent shoulder disease, endocrine issues, and have lifestyles requiring daily concussive activity (jumping in and out of cars, for example) will often require more frequent treatments still.
Given the study outcome, we will now utilize all modalities (laser therapy, weight loss, exercise plans, oral and injectable medications, therapeutic piezo wave, and manual therapies) in the first week of treatment. However, continuing long-term PBM allows for non-invasive, soothing treatments without side effects- an effective treatment regime for these patients. It also provides a substantial reduction in both necessary oral and injectable agents long-term, and it may even thwart the need for invasive joint injection in severe cases of OA.
The elbows and stifles are the neediest joints for chronic analgesic therapy for osteoarthritis by a wide margin. Stifles, unlike elbows, require stability after anti-inflammatory use and seem to reach adequate analgesia sooner; this is likely due to more weight bearing on the forelimbs. However, without stability (and especially with meniscal damage), the stifle can also have much more variance in treatment. Elbows, on the other hand, tend to reach a plateau and do well in ongoing treatments- especially if trigger point, axilla, and shoulders are included.
How do you incorporate these study findings into daily patient treatments, though? There are several ways. Once radiographed and determined to be elbow OA, I will consider mini-scoping for FMCP disease and then offer the owner a program of in-house modalities that includes PBM, therapeutic ultrasound, and manual therapies depending on the patient’s age. An in-home exercise program is then developed. If the owner can afford it, I also recommend an in-hospital program that includes flexion exercise and underwater treadmill therapy. NSAIDs are then started, along with PSGAGs. PBM usually begins twice a week at 15-20 J/cm2 over the entire cranio-caudomedial joint compartment and into the axilla (along RUMM nerve paths); this may require placing the patient in lateral recumbency to access the necessary areas of treatment.
Both elbows are treated in 70% of dogs, even if only one is the source of lameness. By the third or fourth treatment, we are able to reduce the NSAID and continue our PBM therapy once a week for an additional three weeks. Range of motion and ease of daily activities (rising, becoming recumbent, willingness to exercise) as well as overall comfort (family interaction, tail wag) normally improve within a couple of treatments. I recommend continued weekly or bi-weekly treatments for a two-month period, with a progressive focus on the therapy of brachial plexus, shoulder, and muscle (biceps/brachialis, triceps and forearm extensor) trigger points. Many patients from this point on either do not require further treatment or only require treatment during specific times of weather, activity, or comorbidity changes.
Although PBM is only part of the big picture of OA management, I believe it is integral.
I also believe that most of these patients suffer from compensatory myopathy and neurogenic pain, so treating “just the joint” is not sufficient. PBM, on the other hand, can cover a lot of ground easily. Before the pandemic, I would offer skeptical owners a chance to feel the therapy and deliver a treatment on themselves while we offered technical advice nearby; most of these owners immediately felt enough relief to allow us to treat their pet. For feline patients, it’s a revelation in terms of non-invasiveness and attitude during return visits.
Companion Animal Health was instrumental in not only affording us the opportunity to do this study, but also the ability to connect with a great network of unbiased researchers and clinicians (both in the human and veterinary fields) in order to improve our treatment of this severe joint degenerative process.
Experiences treating OA patients with PRP
Some patients with moderate to severe DJD will require more advanced treatments beyond PBM. Many patients with such chronic soft tissue injuries, whether primary or secondary to DJD in nearby joints, may also benefit from more invasive/interventional techniques. PRP (with its milieu of growth factors and anti-inflammatory mediators) can be wonderful localized therapy for the actual joint, the soft tissue trigger points, the strain and sprain of muscles, and the tendons and ligaments that accompany OA.
PRP has what placebo-controlled and blinded evidence lacks in terms of regenerative therapies (IRAP, for instance). The procedure has many studies in support of its use (Fahie, Cuervo, Upchurch, Franklin, et al) and has been easier to procure, process, deemed more efficient, and is more workflow-savvy than BMAC or MSC. Additionally, PRP procurement and refinements for injection are within the acceptable financial limits of most owners and come without the need for deep sedation, anesthesia, or a painful procedure- all of which are common with stem cell therapy.
I find it most helpful to treat the joint with a low dose steroid (under 2 mg methypred acetate or 1mg triamcinolone per joint) first to reduce inflammation diagnostically in order to assist with localizing. If the patient seems to improve, I likely have the joint of issue and will have the owner make the appointment for two PRP injections two weeks apart. The efficacy of the PRP will depend on local anti-inflammatories (steroid injections) and systemic anti-inflammatories (NSAIDs) not being administered for at least a week prior to injection; the harvested platelets need to be active in order to aggregate, interact, and secrete their growth and healing factors.
How does this look for our elbow and stifle OA patients from a practical standpoint? Patients enter the hospital and, under low stress, have a blood draw for roughly 10-30ml of whole blood. While the Companion product insert tells of drawing larger amounts, I will try to appropriately ratio the draw for the ACD dilution required. Processing is easy and based on Sam Franklin and Brit Carr’s papers. The CRT Pure PRP system seems to be massively productive in the amount of final “clean and activated” product that it produces. For the average 20-40 kg dog, you are attempting to gain 1-4 ml of PRP in the injection of 1-3 joints. While some can be frozen for future use, I prefer to use fresh product for each sedated injection.
Patient prep proceeds as follows. First, I utilize much “conscious sedation” using dexmedetomidine and butorphanol administered IV for the degree of necessary clip and prep of the joint, sterile approach, and needle entry. If the joint is effused or chronic (meaning most of the joints we inject), I will flush it with warmed saline roughly 2-10 ml depending on the size of the joint. Don’t expect to get much out of this unless you use an ingress egress system with large gauge needles. Instead, I would expect a “dilution is a solution to pollution” phenomena, meaning you are attempting to get rid of the debris by diluting it and forcing it to the extremities of the joint pouch (If not out of the joint entirely). Once flushed, I will utilize the same entry site for administration of the product.
Entry seems to be easier than the carpus tarsus and coxofemoral joint in stifles and elbows, mostly because we can ascertain entry via joint fluid procurement in the larger joints. However, some chronically inflamed joints seem to be low on joint fluid, so don’t be surprised if fluid is difficult to obtain. For really chronic bone on bone joints, hyaluronate and PRP injection can be very beneficial.
The improvement with PRP injections seems to lag a bit when one considers response to NSAID, PBM, or even steroid injection, with most beneficial responses being seen within 2-4 weeks rather than within the week. Even with some progress in lameness resolution, most owner valued variables appear to improve more dramatically with two treatments vs one.
We will regularly treat muscle and tendon injuries with both PPP and PRP. The former is subjectively more resolving for the actual muscle injury, and the latter is subjectively more important with fascial and tendon injuries. The downfall of both of these treatments is that one must learn to recognize the injury with ultrasound and pinpoint the deposition of the substances. Take it from someone who is too old to have received ultrasound training with a veterinary curriculum: If you start picking up the probe and comparing it side by side to determine normal vs. abnormal, you will quickly start using this imaging modality more frequently. The upside of both of these therapies is that the CRT Pure PRP system can prepare both products from the blood draw. Remember- the P that ends both acronyms refers to “plasma,” which tells of the importance of this aspect of the treatment.
Before long, we will begin utilizing more PRP preps for all kinds of tissue healing. It won’t just be in post op orthopedic, but also in soft tissue in- and out-patient procedures. Platelets seem to be an untapped source of many growth factors, and if cleansed of the appropriate debris (RBCS in particular) and treated well, they may have indications well beyond OA treatment.