Edited by: Madhu S. Dhar, University of Tennessee, USA
Reviewed by: Wanda J. Gordon-Evans, Wisconsin Veterinary Referral Center, USA; Lauren Virginia Schnabel, North Carolina State University, USA
Specialty section: This article was submitted to Veterinary Regenerative Medicine, a section of the journal Frontiers in Veterinary Science
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
To report clinical findings and outcomes for 55 dogs with supraspinatus tendinopathy (ST) treated with adipose-derived progenitor cells and platelet-rich plasma (ADPC-PRP) therapy.
Medical records of client-owned dogs diagnosed with ST that were treated with ADPC-PRP combination therapy were reviewed from 2006 to 2013. Data collected included signalment, medical history, limb involvement, prior treatments, physical and orthopedic examination, objective temporospatial gait analysis findings, diagnostic imaging results (radiography, magnetic resonance imaging, musculoskeletal ultrasonography), arthroscopy findings, and outcome.
Following ultrasound-guided injection of ADPC-PRP, objective gait analysis was available on 25 of the 55 dogs at 90 days post ADPC-PRP therapy. Following treatment, a significant increase in total pressure index percentage (TPI%) was noted in the injured (treated) forelimb at 90 days post treatment (
These findings suggest that ADPC-PRP therapy should be considered for dogs with ST.
Supraspinatus tendinopathy (ST) is a common cause of forelimb lameness in dogs. The etiology of ST is thought to be repeated strain activity and overuse from chronic repetitive activity, with a failure of adequate remodeling (
Diagnostic musculoskeletal ultrasonography is a relatively new technique that has been used and validated for the diagnosis of ST in both humans and dogs (
Previous reports on the treatment of ST in dogs have included both conservative and surgical management (
Mesenchymal stem cells (MSC) found in bone marrow and adipose tissue can differentiate into multiple cell lines, including bone, cartilage, and fibrous connective tissue, such as tendons (
Mesenchymal stem cells have potent anti-inflammatory, anti-fibrosis, pro-angiogenic properties, and can integrate into tendon tissue and contribute to healing (
The purpose of this retrospective study was to describe the effects of adipose-derived progenitor cells and platelet-rich plasma (ADPC-PRP) combination therapy for the treatment of ST in dogs.
In accordance with AAALAC International Rules of Accreditation, this study was performed with the approval of the VOSM Research Committee and with owner consent. All clients volunteered their dog for the study and provided written consent as required by Veterinary Orthopedic and Sports Medicine Group for every study participant. Medical records of client-owned dogs diagnosed with ST that were treated with ADPC-PRP combination therapy were reviewed from 2006 to 2013. Data collected included signalment, history, limb involvement, prior treatments, physical and orthopedic examination, objective temporospatial gait analysis findings, diagnostic imaging results [radiography, magnetic resonance imaging (MRI), musculoskeletal ultrasonography], arthroscopy findings, presence of concurrent shoulder and elbow pathologies, treatments administered, and outcome. Dogs were excluded from this study if there was the presence of concurrent orthopedic or neurological disease, recommended treatment and therapy plans were not adhered to, or if follow-up information was not available.
All patients were evaluated with an orthopedic and neurological evaluation at baseline as well as follow-up at 30, 60, and 90 days post treatment. Shoulder range of motion in flexion, extension, and abduction were recorded. Discomfort was noted if found on shoulder manipulation or direct palpation of the supraspinatus. All other abnormal orthopedic or neurological findings were also recorded.
Routine lateral and craniocaudal radiographs were performed of both shoulders and elbows in all patients at baseline. All radiographs were evaluated for evidence of shoulder and/or elbow pathology by a board certified veterinary surgeon.
Magnetic resonance imaging was recommended for all patients. If elected, patients were placed under general anesthesia and images of the affected shoulder were acquired using a 1.5-T MRI. All images were reviewed by a board certified veterinary radiologist.
Bilateral shoulder musculoskeletal diagnostic ultrasound was performed at baseline and at 45 and 90 days post treatment. Bilateral shoulder musculoskeletal diagnostic ultrasonographic measurements for each dog were performed using Sonosite Edge musculoskeletal ultrasound machine with a 15-6 MHz linear probe. Patients were placed in lateral recumbency, and both shoulder areas were clipped and cleaned. Sedation or anesthesia was not required. Ultrasonographic images of the supraspinatus tendon of both limbs, including transverse and longitudinal images, were obtained (Figures
Objective gait analysis was performed at baseline as well as follow-up at 90 days post treatment. Objective gait analysis was performed in a quiet room using a temporospatial pressure sensing walkway. The walkway system was equipped with a 8.23 m × 0.85 m portable mat containing 29,952 encapsulated sensors.
Every dog was handled by the same examiner and allowed to acclimate to the room prior to data collection. Dogs were walked on the mat until they appeared relaxed (~4–6 passes/dog). Three passes across the walkway were recorded at both the walk and the trot. A pass was defined as a dog moving along the length of the portable walkway system in one direction and consisted of 4–6 gait cycles. Inclusion criteria for a pass were that the dog was at a walk (velocity, 0.9–1.2 m/s) or a trot (velocity, 1.8–2.6 m/s), had minimal head turning, and that gait cycle velocities did not vary by more than 10%. The first three passes that met the inclusion criteria were analyzed for each dog. Videos of each pass were reviewed to ensure that all inclusion criteria were met.
The software program was used to identify the paw print of each footfall. The software program then performed analysis of multiple variables for each pass. Data gathered or calculated from each pass provided the total pressure index percentage (TPI%) for each foot (the sum of peak pressure values recorded from each activated sensor by a paw during mat contact/total sum of peak pressure values for all feet × 100) (
Diagnostic elbow and shoulder arthroscopy was performed to rule out the presence of concurrent intra-articular pathology. A standard medial portal was utilized for arthroscopic evaluation of the elbow. Following routine aseptic preparation of the elbow, a 22-gage needle was placed into the elbow in the medial compartment. Synovial fluid was aspirated using a 5-ml syringe to ensure the needle was in the joint. Approximately 5 ml of saline was then injected into the elbow to distend the joint. A 15 blade was used to create a stab incision through the skin to allow for insertion of the cannula and trochar into the elbow. The 1.9-mm arthroscope was then inserted into the cannula. Arthroscopic evaluation was performed to confirm no signs of pathology.
A standard lateral portal was utilized for arthroscopic evaluation of the affected shoulder. Following aseptic preparation, a 22-gage needle was placed into the shoulder. Synovial fluid was aspirated using a 5-ml syringe to ensure that the needle was in the joint. Approximately 5–10 ml of saline was then injected into the shoulder to distend the joint. A 15 blade was used to create a stab incision through the skin to allow for insertion of the cannula and trochar into the shoulder. The 1.9-mm arthroscope was then inserted into the cannula. The shoulder was then assessed without the fluid pump activated in order to observe the joint in a more natural environment without significant distension. This would allow for identification of a supraspinatus bulge. The biceps, subscapularis tendon, MGL, joint capsule, and cartilage were observed to confirm no evidence of pathology.
Patients were pre-medicated with 0.1 mg/kg hydromorphone intramuscularly, 0.2 mg/kg midazolam intramuscularly, and 0.5 mg/kg famotidine subcutaneously. General anesthesia was induced using intravenous propofol to affect. The abdomen was clipped and aseptically prepared for surgery. A 4-cm incision was made in midline in the cranial abdomen. A 2-cm incision was made through the linea. The falciform ligament was identified. Approximately 20 g of falciform adipose tissue was collected and placed into a sterile container with Delbecco’s modified Eagle’s medium (DMEM) supplemented with fetal bovine serum (FBS), penicillin, and streptomycin. The sample was then prepared for shipment. A routine closure was performed.
The jugular vein was clipped and aseptically prepared. Approximately 30 ml of blood was collected using an 18-gage butterfly needle into a syringe with 5 ml of CPDA anti-coagulant. The sample was then prepared for shipment.
Adipose and blood samples were shipped in validated containers at 4°C to Virginia Tech’s Regenerative Medicine Research Laboratory for processing as per US patent application number #62050792. Adipose was processed using established techniques (
Platelet-rich plasma was prepared from anti-coagulated blood via centrifugation first for 10 min at 800 g, then the platelet-rich supernatant above the buffy coat was centrifuged at 4,000 ×
Ultrasound guidance was used to administer ADPC-PRP therapy with a fenestration technique (
All patients were enrolled in rehabilitation therapy following ADPC-PRP therapy. For the first 8 weeks, each patient participated in once weekly manual/massage therapy, class IIIb low-level laser therapy for the affected shoulder (5 J/cm2), and a twice daily at home exercise program. Additionally, at 8 weeks following treatment, patients were allowed to start hydrotherapy with underwater treadmill. No NSAIDs, corticosteroids, class IV low-level laser therapy, therapeutic ultrasound, or TENS/NMES were permitted at any time during the first 8 weeks, nor were any of these treatments required during the remaining recovery period in any of the patients.
Statistical analysis of CSA over time and TPI over time was performed using repeated measures ANOVA with
Medical records of 55 dogs diagnosed with unilateral ST treated with ADPC-PRP therapy were reviewed. Age ranged from 1 to 14 years (average 6.4 years, median 6 years). No sex predisposition was apparent with 26 female dogs (1 intact) and 29 male dogs (2 intact). There were 13 Border Collies, 13 Labrador Retrievers, 7 German Shepherd Dogs, 5 Mixed Breed Dogs, 3 Boxer Dogs, 3 Welsh Corgis, 3 Golden Retrievers, 2 Bernese Mountain Dogs, and 1 of each of the following: Basenji, Greater Swiss Mountain Dog, Standard Poodle, Rhodesian Ridgeback, Rottweiler, and Wheaton Terrier (Table
Breed | Number of patients |
---|---|
Basenji | 1 |
Bernese Mountain Dog | 2 |
Border Collie | 13 |
Boxer | 3 |
Corgi | 3 |
German Shepherd Dog | 7 |
Golden Retriever | 3 |
Greater Swiss Mountain Dog | 1 |
Labrador Retriever | 13 |
Mixed Breed | 5 |
Poodle – Standard | 1 |
Rhodesian Ridgeback | 1 |
Rottweiler | 1 |
Wheaton Terrier | 1 |
Occupation | % of patients |
---|---|
Agility | 37 |
Field trial | 7.4 |
Flyball | 7.4 |
Herding | 7.4 |
Hunting | 3.7 |
Obedience | 18.5 |
Rally | 7.4 |
Show | 11.1 |
Routine lateral and craniocaudal radiographs were performed of both shoulders and elbows in all patients at baseline. Mineralization of the affected supraspinatus tendon was noted in eight cases (14.5%) (Figure
Magnetic resonance imaging of the shoulder was performed in 31 of the 55 cases. Of these 31 cases, findings indicative of a ST include hyperintensity of signal on T1 and STIR sequences of the ST at its insertion on the greater tubercle (Figure
Cross-sectional area of the treated (ADPC-PRP injected) tendon was compared to the contralateral (non-affected) tendon at baseline and at 90 days post treatment.
There was a significant difference in CSA noted between the injured and contralateral normal supraspinatus tendon prior to ADPC-PRP therapy (
Following ultrasound-guided injection of ADPC-PRP therapy, objective gait analysis was available on 25 of the 55 dogs at 90 days post ADPC-PRP therapy. TPI% of the treated forelimb was compared to the contralateral (non-affected) forelimb at baseline and at each follow-up evaluation. Results of objective gait analysis showed a significant difference in TPI% between the injured and contralateral normal forelimb prior to injection with the injured limb having a lower TPI% (
Based on the objective gait analysis and diagnostic ultrasound results, ADPC-PRP therapy appears to be promising for dogs with ST, especially those who have failed to respond to conservative management and rehabilitation therapy. Measurable improvement in lameness as indicated by TPI, and in CSA, was seen over time and/or in comparison to contralateral normal tendons.
When considering treatment options for ST patients, it is important to note that many of the patients failed to respond to conservative management prior to presentation as 61.8% of patients failed to respond to NSAID therapy and 45.5% failed to respond to rehabilitation therapy. This may suggest that conservative management is often insufficient to treat ST. While dogs treated surgically have been shown to improve in gait and overall comfort, regenerative medicine therapy also shows promising results and should be considered for dogs with ST. Future studies are needed to further evaluate the use of regenerative medicine therapy for ST and other tendon injuries in the canine.
Limitations of this study are primarily related to the nature of a retrospective study, and the use of a combination therapy. Future studies should be randomized, blinded, and controlled. While there was no placebo control, 61.8% had previously failed to respond to NSAID therapy and 45.5% had previously failed rehabilitation therapy. Initially, our group treated refractory cases of ST with PRP alone. This treatment in a limited number of cases subjectively did not seem to improve healing by ultrasonographic evaluation, and PRP therapy was abandoned in favor of the described ADPC-PRP therapy. In contrast to PRP alone, initial cases treated with ADPC/PRP therapy showed subjective improvement in both echogenicity and lameness. A small pilot study using a leukocyte and platelet-rich plasma alone to treat ST in 10 dogs improved lameness and function (
In conclusion, ADCP in combination with PRP may provide an adequate biologic effect leading to tendon healing and improved function. Because of the limited efficacy of current non-surgical management, consideration should be given to the use of regenerative medicine interventions in tendons that demonstrate poor natural healing potential.
We certify that all authors meet the qualifications for authorship as listed below: (1) substantial contributions to the conception or design of the work or the acquisition, analysis, or interpretation of data for the work; (2) drafting the work or revising it critically for important intellectual content; (3) final approval of the version to be published; (4) agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
ADPC, adipose-derived progenitor cells; MSC, mesenchymal stem cells; PRP, platelet-rich plasma; ST, supraspinatus tendinopathy; TPI%, total pressure index percentage.
1GaitFour Pressure Sensing Walkway, platinum version, CIR Systems Inc., Harvertown, PA, USA.
2GaitFour, platinum version, CIR Systems Inc., Harvertown, PA, USA.
3Logitech MP web camera, Logitech, Freemont, CA, USA.
4GraphPad Prism 6, GraphPad Software Inc., La Jolla, CA, USA.