Extracorporeal shockwave therapy for treatment of superficial digital flexor tendonitis in racing Thoroughbreds: 8 clinical cases

Blood flow restriction training does not negatively alter the mechanical strength or histomorphology of uninjured equine superficial digital flexor tendons

BACKGROUND

Low load exercise training with blood flow restriction (BFR) has become increasingly used by human physical therapists to prescribe controlled exercise following orthopaedic injury; its effects on the equine superficial digital flexor tendon (SDFT), however, are unknown.

OBJECTIVE

To investigate outcomes of pressure specific BFR walking exercise on uninjured equine SDFT biomechanics and histomorphology.

STUDY DESIGN

Controlled in vivo experiment.

METHODS

Four forelimbs of four horses were exposed to 40 BFR-walk sessions (10-min interval walking) on a treadmill over a 56-day study period with their contralateral forelimbs serving as untreated controls. Similarly, four forelimbs of four control horses were exposed to 40 sham cuff walk sessions. On study Day 56, all horses (n = 8) were humanely euthanised and forelimb SDFTs underwent non-destructive biomechanical testing and corresponding histomorphological analysis. Significance in biomechanical parameters between treatment groups was analysed using a mixed-effects ANOVA with Tukey's post-hoc tests.

RESULTS

Statistically significant differences in SDFT stiffness for both first (p = 0.02) and last cycles (p = 0.03) were appreciated within the BFR treated group only, with BFR exposed forelimbs being significantly stiffer than the contralateral unexposed forelimbs. When normalised to cross-sectional area, no significant differences were appreciated among treatment groups in elastic modulus for the first (p = 0.5) or last cycles (p = 0.4). No histological differences were appreciated among treatment groups according to Bonar, Movin, or musculotendinous junction evaluation criteria.

MAIN LIMITATIONS

Short-term comparisons were performed in a small sample population without correlation to performance outcome measures. Optimal occlusion percentages and walk protocols remain unknown.

CONCLUSIONS

This study demonstrated no negative impact of BFR on mechanical strength of the equine SDFT; however, evidence suggests that BFR results in increased tendon stiffness based on biomechanical testing and subsequent calculations. No consistent detrimental histomorphological changes were seen.

Electrohydraulic shockwave for treatment of forelimb superficial digital flexor tendinitis and proximal suspensory desmitis in horses

Superficial digital flexor tendinitis (SDFT) and proximal suspensory desmitis (PSD) are common causes of lameness in horses. Current treatment options include rest, controlled exercise, administration of anti-inflammatories, intralesional injections, surgery, and electrohydraulic shock wave therapy (ESWT). ESWT is safe, noninvasive, and is used to treat a variety of musculoskeletal abnormalities. Medical records between 2010 and 2021 were reviewed. Horses were separated into two categories: (group 1: ≥ 3 ESWT treatments; group 2: < 3 ESWT treatments). Our objective was to examine the effect of the number of ESWT treatments in the management of SDFT and PSD injuries and to compare short- and long-term outcomes for the two groups. For group 1, lameness scores between the first and third treatments were significantly reduced in both PSD (p<0.0001) and SDFT (p=0.016) horses. However, neither the PSD (p=0.062) nor SDFT's (p=0.125) ultrasound findings were significantly different at the end of the third treatment. Horses with PSD showed a significant improvement in forelimb lameness between the first and third treatments compared to hindlimb (p = 0.033). In the multivariable ordered logistic regression model, only time (months of follow-up) was significantly associated with a positive outcome (p=0.001) and there was no difference in short and long-term outcome between groups 1 and 2. Also, chronicity of injury was negatively associated with improvement of lameness (p=0.028).

Systematic Review of Complementary and Alternative Veterinary Medicine in Sport and Companion Animals: Extracorporeal Shockwave Therapy

BACKGROUND

Extracorporeal shockwave therapy (ECSWT) is increasingly used to treat different types of musculoskeletal conditions in sport and companion animals. To explore the scientific basis for the treatment, we conducted a systematic review of the literature on ECSWT used in horses, dogs, and cats.

METHODS

Relevant articles published in 1980-2020 were identified from three major databases. Each article was assessed for risk of bias.

RESULTS

The review identified 27 relevant articles on the effects of ECSWT in horses, nine in dogs, but none in cats. Typically, ECSWT involved one to three treatment sessions at 1- to 3-week intervals. We identified studies on bone mass and bone healing, wound healing, navicular disease, ligament injury, desmitis, sesamoiditis, tendon injury, osteoarthritis, and short-term analgesic effects. Common to all indications was that the scientific evidence was very limited. For each separate indication, there were relatively few studies, many of which had methodological flaws. Where favorable results were reported, they were usually not replicated in independent studies. A few encouraging results were found.

CONCLUSIONS

In sport and companion animals, the scientific evidence for clinical effects of ECSWT in horses, dogs, and cats is limited. For some applications, notably short-term pain relief, ligament ailments, and osteoarthritis, the results seem promising and warrant further exploration in high-quality studies.

Feline pantarsal arthrodesis using pre-contoured dorsal plates applied according to the principles of percutaneous plate arthrodesis

Objective: To describe the surgical technique for pantarsal arthrodesis (PTA) in cats according to the principles of percutaneous plate arthrodesis with application of a pre-contoured dorsal plate, without external coaptation and to report the long-term clinical outcome.

Materials and methods: Retrospective review was performed of all cats treated by percutaneous plate application using a new pre-contoured dorsal plate for PTA between 2008 and 2011. Inclusion criteria were clinical and radiographic records plus clinical follow-up to at least six weeks. Data recorded included signalment, indication for surgery, postoperative care, and complications encountered. Radiographs were assessed for arthrodesis progression and complications. Outcome was assessed using an owner questionnaire.

Results: Eleven cats were treated for tarsal injuries and met the inclusion criteria. Mean age was 86 ± 45 months, weight 4.50 ± 0.92 kg. The only major short-term complication encountered was wound dehiscence requiring sedation and re-suturing. In the medium-term (23.3 months ± 11.6 months) eight out of nine cats returned to normal activity and one cat showed intermittent lameness. Long-term (34.3 months ±17.5 months) radiographic evaluation was performed in seven out of nine cats; six manifested complete arthrodesis and one sustained plate breakage. Based on owner questionnaire, all nine cats returned to normal activity in the long-term, even the case with plate breakage.

Conclusion: Based on our results, PTA using a custom pre-contoured dorsal plate is a suitable salvage surgery for treatment of severe tarsal injuries in cats.