- Platelet-rich plasma (PRP) has been applied as a hemostatic agent since the 1970s, and a potent source of autologous growth factors since the 1990s. PRP is rich in growth factors such as platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), fibroblast growth factor (FGF) and platelet factor-4 (PF-4). With these factors, PRP can enhance regenerative processes and facilitate tissue repair by significantly increasing cell migration, chemotaxis proliferation, differentiation and angiogenesis. PRP plays a strong role in orthopedic injuries, in particular sports medicine, in the enhancement of bone, muscle, ligament, tendon and cartilage healing.
The application of PRP in human musculotendinous injuries such as Achilles tendon and rotator cuff has had favorable clinical outcomes with very limited reports such usage in veterinary medicine. The first pilot study enrolled 10 dogs with supraspinatus tendinopathy to assess the short-term outcome of a single injection of
autologous PRP. Dogs were assessed at 2 weeks, 6 weeks and >16weeks using both objective (gait analysis, ultrasound) and subjective (canine brief pain inventory score and lameness examination) measures. Results showed 40% of dogs had clinically resolved lameness by 6 weeks, with 50% returning to normal function at final evaluation. However, 6 dogs had persistent lameness, hence a single injection of PRP cannot consistently improve clinical lameness in dogs with supraspinatus tendinopathy.
Current research investigating alternative methods of simulating repair of damaged cartilage is an emerging field in both human and veterinary medicine. PRP has been promoted to enhance joint homeostasis, reduce synovial membrane hyperplasia and modulate synovial fluid cytokine levels. The second pilot study enrolled 10 dogs with coxofemoral osteoarthritis treated with a single intra-articular injection of autologous PRP. Objective measurements of lameness (radiographs, goniometry, accelerometry gait analysis) and subjective measures (canine brief pain inventory score and lameness examination) were assessed at 2 weeks and 6 weeks post-treatment. Both subjective and objective data did not find significant difference from pre-treatment to post-treatment evaluation at 2 and 6 weeks. Further research with a larger cohort of patients, longer follow-up times and with a series of PRP injections rather than a single dose is required to determine the clinical efficacy of PRP application in musculoskeletal disorders in the dog.