Treatment of chronic proximal suspensory desmitis in horses using focused electrohydraulic shockwave therapy

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.

Effectiveness of Platelet-Rich Plasma and Bone Marrow Aspirate Concentrate as Treatments for Chronic Hindlimb Proximal Suspensory Desmopathy

This retrospective study aimed to evaluate the clinical effect of bone marrow aspirate concentrate (BMAC) and leukocyte rich PRP (LR-PRP) compared to horses undergoing controlled exercise alone in horses with >3 months proximal suspensory desmopathy in hindlimbs (HPSD). Nighty-three horses were divided into three groups according to the treatment: a control (n = 22), LR-PRP (n = 46), and BMAC (n = 25) group. Lameness and ultrasound scores were recorded before treatment (T0) and at 6 months (T1) post-treatment. Records horses considered sound at evaluation and level of performance were additionally registered at 12 months (T2) and 18 months (T3) after treatment. The BMAC cytology profiles from 22 horses were also analysed and compared to clinical outcomes. The results at T1 showed that 9% (2/22) of the horses in the control group were sound compared to 59% (25/46) and 84% (21/25) in the LR-PRP and BMAC groups, respectively. Additionally, ultrasound scores at T1 in the BMAC and LR-PRP groups were improved in comparison with the control group (p = 0.02). At T2, 68% of the horses in the BMAC group and 39% of the horses in the LR-PRP group had returned to the previous performance level. At T3, a significantly higher percentage of horses in the LR-PRP (43%) and BMAC (72%) group were sound when compared to the control (4.6%) group (p = 0.02). Similarly, at T3, significantly more horses of the BMAC (16/25) and of the LR-PRP (15/46) group had returned to the previous or a higher performance level compared to the control (1/22) group (p = 0.01). No correlation was found between long-term clinical outcome and cytology profiles in the BMAC group. In conclusion, long-term outcomes of treatment with LR-PRP or BMAC are significantly better than conventional treatment of the hindlimb chronic PSD in horses. Additionally, BMAC yielded better lameness scores than LR-PRP at short- and long-term follow-up.

Prospective randomized comparison of platelet rich plasma to extracorporeal shockwave therapy for treatment of proximal suspensory pain in western performance horses

Proximal suspensory desmitis (PSD) is a frequent cause of lameness in the performance horse. Extracorporeal shockwave therapy (EST) and platelet rich plasma (PRP) have become common treatments for PSD yet clinical data on efficacy is limited. The main objective of this randomized, prospective clinical study was to compare long-term effectiveness of EST and PRP in Western performance horses. One hundred horses with lameness localized to the proximal suspensory ligament received treatment with either PRP or EST following baseline ultrasonographic evaluation. A veterinarian and agent evaluated the horses for lameness independently four days following the first treatment and long-term follow up was obtained from the agent at six and twelve months. Four days post treatment, horses treated with EST had significantly greater lameness improvement compared to PRP. At one-year horses with less severe baseline ultrasound changes (grades 0-1) appeared to respond better (degree of lameness) with EST treatment whereas horses with more severe ultrasound changes (grade 2) responded better to PRP. Horses with baseline lameness graded 1 or 2 were 5.1 times more likely to be back in work at 1 year compared to those presenting with grade 3 or 4. EST treatment was associated with going back to work 3.8 times more at one year compared to PRP independent of baseline ultrasound score. Both PRP and EST can be expected to yield favorable therapeutic responses in Western performance horses with lameness localized to the proximal suspensory region. Baseline ultrasound may guide treatment selection.

Comparison of Metzenbaum scissors and Y-shaped fasciotome for deep metatarsal fasciotomy for the treatment of proximal suspensory ligament desmopathy in horses

OBJECTIVE

To quantitate the iatrogenic injury associated with deep plantar metatarsal fasciotomy performed with Metzenbaum scissors compared with a Y-shaped fasciotome.

STUDY DESIGN

Experimental ex vivo surgical study.

STUDY POPULATION

Cadaveric hind limbs (n = 20) from 10 sound thoroughbred racehorses.

METHODS

A plantar metatarsal fasciotomy was performed, extending from the proximal extent of the deep metatarsal fascia, distally. Hind limbs were randomly assigned to 2 groups, undergoing fasciotomy with straight Metzenbaum scissors (n = 10) or a Y-shaped fasciotome (n = 10). Magnetic resonance imaging was performed before and after surgery to identify the maximal depth of any iatrogenic trauma. Gross examination of the surgical site included measuring the length of the incision in the deep metatarsal fascia and localizing iatrogenic trauma sustained by the plantar aspect of the proximal suspensory ligament (PSL) during the procedure.

RESULTS

Iatrogenic injury to the PSL was identified in 6 of 10 and 9 of 10 specimens prepared with the fasciotome and Metzenbaum scissors, respectively (P = .03), and was most commonly located in the distal third of the fascial incision. Differences between the length of incision (P = .02) and the maximal depth of signal (P = .03) for incisions created with Metzenbaum scissors or a fasciotome were identified.

CONCLUSION

The use of a fasciotome resulted in longer fascial incisions and less severe iatrogenic trauma to the PSL compared with using Metzenbaum scissors.

CLINICAL SIGNIFICANCE

A Y-shaped fasciotome may be the preferred surgical instrument for successful desmopathy of the PSL fasciotomy because a greater release of compartmental pressure is possible through a longer incision with minimal iatrogenic trauma to the underlying PSL.

A review of the cellular and molecular effects of extracorporeal shockwave therapy

Extracorporeal shockwave therapy (ESWT) is a novel therapeutic modality and its use in promoting connective tissue repair and analgesic effect has been advocated in the literature. It is convenient, cost-effective, and has negligible complications; it therefore bypasses many of the problems associated with surgical interventions. This paper reviews the proposed mechanisms of action in promoting tissue repair and regeneration as well as analysing its efficacy providing an analgesic effect in clinical applications. Further research will be required to not only identify the underlying mechanisms more precisely, but will also be critical for ensuring consistency across the literature so that the most beneficial treatment protocol can be developed. Extracorporeal shockwave therapy stands as a promising alternative modality in promoting tissue repair.

Extracorporeal Shockwave Therapy Increases Growth Factor Release from Equine Platelet-Rich Plasma In Vitro

Introduction

Extracorporeal shockwave therapy (ESWT) and platelet-rich plasma (PRP) are common treatments for soft tissue injuries in horses. Shockwave triggers cell specific responses to promote healing. Growth factors released from PRP also promote healing. It has been hypothesized that greater growth factor release would amplify the healing process. The combination of ESWT and PRP could promote healing in injured tendons and ligaments in the horse. The objective of this study was to determine if application of shockwaves to PRP samples increases the concentration of transforming growth factor-β₁ (TGF-β₁) and platelet-derived growth factor ββ (PDGF-ββ) released from the platelets in vitro.

Materials and methods

PRP was produced from blood drawn from six horses. The PRP from each horse was exposed to the following treatments: (1) positive control (freeze-thaw cycle), (2) untreated negative control, or shockwaves with either (3) a "standard probe" (ESWT-S) with a 2 cm focal width and medium energy density or (4) a "power probe" (ESWT-P) with a 1 cm focal width and high energy density. After each treatment, the samples were centrifuged, and the supernatant was harvested. The supernatant was then used for growth factor quantification via commercially available ELISA kits for TGF-β₁ and PDGF-ββ.

Results

Concentrations of TGF-β₁ and PDGF-ββ in PRP that underwent a freeze-thaw cycle were significantly increased compared with all other treatments. Both ESWT-S and ESWT-P resulted in significantly increased TGF-β₁ concentrations, 46 and 33%, respectively, when compared with the negative control. Both ESWT-S and ESWT-P resulted in significantly increased PDGF-ββ concentrations, 219 and 190%, respectively, when compared with the negative control.

Discussion

These data indicate that the application of ESWT to PRP increases the expression of growth factors in vitro. This suggests that the combination therapy of local PRP injection followed by ESWT may stimulate release of growth factors from platelets after they have been injected into the area of injury.

Conclusion

The combination of PRP and ESWT might result in synergism of two modalities previously utilized individually for tendon and ligament injuries in horses.

Electrophysical Therapies for the Equine Athlete

A good rehabilitation program takes into account the possible causes for the injury. Once the underlying cause of the injury is determined, a veterinarian can construct an appropriate rehabilitation plan and use the available electrophysical therapies to their greatest effect. Treating the horse correctly for the type and location of injury, and the stage of rehabilitation of the tissue, helps ensure full rehabilitation success. This article discusses when and how to use the most common electrophysical therapies in horses including transcutaneous electrical nerve stimulation, neuromuscular electrical stimulation, functional electric stimulation, pulsed electromagnetic field therapy, therapeutic ultrasound, laser therapy, shockwave therapy, and vibration therapy.

Practical Rehabilitation and Physical Therapy for the General Equine Practitioner

Physical treatment and rehabilitation play major roles in recovery and maintenance of the equine athlete, and many therapeutic measures are accessible by the veterinarian in general practice. An accurate diagnosis of the condition undergoing treatment is a requirement, and measurable parameters obtained at diagnosis allows for quantification of treatment outcomes. Therapeutic modalities accessible to the general practicing veterinarian are reviewed. Mechanisms of action, indications, and treatment protocols of thermal therapy, therapeutic ultrasound, extracorporeal shock wave, and laser are discussed. Manipulative therapies, including stretching and use of core strengthening exercises and equipment, are outlined.

Proximal suspensory desmopathy in hindlimbs: A correlative clinical, ultrasonographic, gross post mortem and histological study

REASONS FOR PERFORMING STUDY

It has been suggested that ultrasonography is unreliable for the detection of hindlimb proximal suspensory desmopathy (PSD) based on comparisons between ultrasonographic and magnetic resonance images.

OBJECTIVES

To compare ultrasonography with gross and histopathological post mortem examination in horses with PSD diagnosed based on ultrasonography and control horses.

STUDY DESIGN

Retrospective descriptive study.

METHODS

Part 1: 19 horses with hindlimb PSD and 10 control horses were humanely destroyed. Twenty control limbs and 37 lame limbs were examined grossly and 40 suspensory ligaments (SLs) were examined histologically and graded blindly. Part 2: 3 horses with recurrent lameness after surgical management of PSD and 4 with PSD were assessed ultrasonographically and by gross post mortem examination.

RESULTS

Part 1: ultrasonographic lesions were graded moderate in 31/38 (81.6%) and severe in 7/38 (18.4%) lame limbs; in 4/37 (10.8%) limbs adhesion formation between the proximal aspect of the SL and the accessory ligament of the deep digital flexor tendon was predicted. Gross post mortem and histological examinations of control limbs revealed no abnormalities. Gross post mortem examination revealed substantial adhesions between the proximal aspect of the SL and adjacent soft tissues in 10/37 (27.0%) lame limbs; in 10/37 (27.0%) limbs there were adhesions between the body of the SL and the mid plantar aspect of the third metatarsal bone, extending distally in 6 (16.2%) limbs. Histology revealed abnormalities (grades 1-3) of the collagenous tissue in 25/36 (69.4%) limbs; muscle was abnormal (grades 1-3) in 35/36 (97.2%) limbs and adipose tissue (grades 1-3) in 16/36 (44.4%) limbs. Part 2: adhesions between the SL and adjacent soft tissues were predicted ultrasonographically and confirmed post mortem.

CONCLUSIONS

Ultrasonography was reliable for the detection of SL pathology based on histology as the gold standard. Adhesions may be a reason for recurrent lameness after surgery.

Management of hindlimb proximal suspensory desmopathy by neurectomy of the deep branch of the lateral plantar nerve and plantar fasciotomy: 155 horses (2003-2008)

REASONS FOR PERFORMING STUDY

Neurectomy of the deep branch of the lateral plantar nerve and plantar fasciotomy have become accepted as methods of treatment of proximal suspensory desmopathy (PSD), but there are limited long-term studies documenting the outcome.

OBJECTIVES

To describe long-term follow-up in horses with PSD alone or with other injuries contributing to lameness and poor performance, including complications, following neurectomy and fasciotomy.

METHODS

Follow-up information was acquired for 155 horses that had undergone neurectomy and fasciotomy for treatment of PSD between 2003 and 2008. Success was classified as a horse having been in full work for >1 year post operatively. Horses were divided into 3 groups on the basis of the results of clinical assessment and diagnostic analgesia. Horses in Group 1 had primary PSD and no other musculoskeletal problem. Horses in Group 2 had primary PSD in association with straight hock conformation and/or hyperextension of the metatarsophalangeal joint. Horses in Group 3 had PSD and other problems contributing to lameness or poor performance.

RESULTS

In Group 1, 70 of 90 horses (77.8%) had a successful outcome, whereas in Group 3, 23 of 52 horses (44.2%) returned to full function for >1 year. Complications included iatrogenic damage to the plantar aspect of the suspensory ligament, seroma formation, residual curb-like swellings and the development of white hairs. All horses in Group 2 remained lame.

CONCLUSIONS AND CLINICAL RELEVANCE

There is a role for neurectomy of the deep branch of the lateral plantar nerve and plantar fasciotomy for long-term management of hindlimb PSD, but a prerequisite for successful management requires recognition of risk factors for poor outcome including conformation features of straight hock or fetlock hyperextension.