Pulsed electromagnetic field (PEMF) therapy is a treatment modality for horses in which pulses of electromagnetic fields are directed at specific parts of the body. Research suggests that PEMF can improve bone healing rates, regenerate and protect cartilage cells, and reduce pain and inflammation. [1]

Equine veterinarians commonly use PEMF to treat musculoskeletal injuries such as bone fractures, arthritis, and soft tissue damage in horses. [2] Some practitioners may use PEMF as part of an ongoing wellness routine to heal microfractures or microtears and reduce inflammation. [2]

More research is necessary to determine the efficacy of PEMF in treating common lameness conditions in horses. Although equine research is lacking, the potential benefits and minimal side effects of PEMF make it a desirable treatment option for owners and veterinarians to support healing and recovery.

PEMF Therapy in Horses

The use of pulsed electromagnetic field (PEMF) therapy originated when researchers discovered stress applied to a bone during weight bearing induced an electrical current within the bone cells. [3]

Researchers found these electrical currents enable bone tissues to sense mechanical forces, stimulating tissue remodeling (bone regeneration and structural changes) to better compensate for load bearing. [3]

PEMF therapy leverages this concept by producing an electrical current within the tissue, with the hypothesis that the stimulation will trigger tissue remodeling without having to apply additional mechanical stress to the bone. [3]

How PEMF Works

PEMF technology uses magnetic fields to create electrical currents within tissues. This makes it different from traditional electrical current therapies (e.g. shockwave therapy) in which an electrical current is produced directly by the machine. [3] This allows PEMF treatment to affect deeper tissues that other therapies cannot access using standard treatment methods. [3]

PEMF machines use coils of copper wire to produce an electromagnetic current. [1] By running electricity through the wires, the travelling electrons produce a magnetic field. [1]

The shape of the coil within the machine dictates the shape of the electromagnetic field. [1] Many PEMF machines have coils designed to produce a strong local effect so the practitioner can direct treatment to a specific area. [1]

Many PEMF machines also incorporate traditional electrical current treatment functionality as part of the device. [3] This allows practitioners to combine the effects of electrical current treatment, such as shockwave, with the effects of PEMF therapy.

Effects on Tissue

Research on the impact of PEMF therapy on equine tissues is limited, but there are several studies from human medical literature. These studies report variable efficacy, with one review showing that only 51% of PEMF studies identified cellular changes. [3]

According to studies showing positive effects of PEMF therapy, possible tissue changes include: [1]

  • Increased bone production (osteogenesis)
  • Increased regeneration of cartilage cells
  • Improved cartilage cell survival in joint tissues
  • Anti-inflammatory effects in treated tissues
  • Proliferation of stem cells

Bone Production

Many studies in PEMF-treated cells report cell proliferation or growth. [3] In particular, PEMF therapy increases proliferation of osteoblasts, the main cells responsible for producing new bone tissue. [3]

These findings are the basis for using PEMF therapy to treat bone fractures, as practitioners hypothesize increasing osteoblast proliferation promotes healing in the bone. [3]

Regeneration and Protection of Cartilage

Research suggests cartilage tissues may also respond to electrical stimulation, similar to bone. [1]

Research on the effects of PEMF on joint tissues shows that PEMF increases proliferation and survival of chondrocytes, the cells within joint cartilage. [1]

When cartilage is compressed during weight bearing, the fluid component of the cartilage is pushed out, and electrolytes (electrically charged minerals) within the fluid may produce an electrical current. [1] These electrical currents may produce a proliferation effect in cartilage, allowing it to compensate for increased load bearing. [1]

Studies also show that PEMF can increase the production of proteoglycan, a major component of cartilage. [1] Proteoglycan holds fluid within cartilage tissues, allowing the cartilage to act as a protective cushion during weight bearing. This cushioning effect pads the bones of the joint so they are not in direct contact, preventing pain associated with bone-on-bone rubbing and grinding when the joint is in use.

These findings suggest that PEMF may have applications in treating arthritis, a disease where the joint cartilage degenerates and causes pain. [1]

Anti-inflammatory Changes

Studies in rats show that PEMF may have an anti-inflammatory effect. [1] PEMF treatment can decrease the activity of neutrophils, a major inflammatory cell in the immune system. [1] Decreasing the activity of these cells can have a protective effect on structural cells within the joint capsule. [1]

Additionally, other studies show PEMF treatment can decrease levels of prostaglandin in a treated area. [1] Prostaglandin is a major inflammatory protein that plays a role in the pain sensation associated with inflammation. By decreasing prostaglandin levels in an area, PEMF may reduce pain perception and improve comfort. [1]

Stem Cell Proliferation

There is considerable research into the effect of PEMF on stem cells. Studies show PEMF can stimulate stem cells to transform into osteoblasts and chondrocytes. [3] As stem cell therapy is an increasingly popular treatment for lameness in horses, these findings suggest that PEMF therapy may have a synergistic effect with stem cell treatment.

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Uses in Equine Medicine

Most veterinarians use PEMF treatment to encourage healing in bone fractures or soft tissue injuries. [2] PEMF treatment may also reduce muscle pain and muscle spasm. [2]

Treatment protocols often depend on the specific machine used, and vary significantly. [2] Typical treatment protocols range from 30 minutes per day up to 8 hours per day. [1][2] PEMF can be used daily, with reports of daily use for up to 8 weeks in dogs. [2]

Each machine produces a slightly different electromagnetic field, which may have a different effect depending on the treatment area, frequency of treatment, and duration of treatment session. [3] Therefore, standardizing PEMF treatment protocols is difficult in both human and equine medicine. [2][3]

Parameters of the electromagnetic fields that vary between machines include: [3]

  • Intensity of the magnetic field
  • Duration of the pulses
  • Frequency of the pulses
  • Shape of the electromagnetic pulse

Some machines allow practitioners to adjust these settings to produce a desired effect. [1][2] There are currently few studies describing ideal PEMF treatment protocols for different conditions, so most practitioners use previous experience and anecdotal evidence to design a treatment protocol for each case. [2]

Scientific Evidence

Although most practitioners use PEMF to promote bone healing, there are several studies investigating uses of PEMF in treating other conditions. Further studies are necessary to determine the efficacy of PEMF for treating various conditions in horses and to design corresponding  treatment protocols.

Bone Healing

Most studies in equine literature focus on the use of PEMF in lameness cases, particularly injuries to bone. This parallels human medicine, where doctors use PEMF in orthopedic medicine to stimulate bone regeneration. [3]

Studies in human medicine show that PEMF can reduce healing time of bone fractures and may reduce associated pain. [3] In particular,