Red and Infrared Light Therapy for Suspensory Ligament Injuries in Horses

Understanding the Suspensory Ligament

Suspensory ligament injuries are among the most common and challenging soft-tissue conditions in performance horses. Due to the ligament’s biomechanical role and limited vascular supply, healing timelines can be prolonged and recurrence risk is significant.

Red and near-infrared light therapy (photobiomodulation) is increasingly integrated into structured rehabilitation programs to support circulation, cellular energy production, and collagen organization within suspensory tissue.

The suspensory ligament originates at the proximal aspect of the third metacarpal (forelimb) or third metatarsal (hindlimb) bone and extends down the cannon region.

It then:

• Divides into medial and lateral branches
• Attaches to the proximal sesamoid bones
• Sends an extensor branch forward to join the common digital extensor tendon

The suspensory ligament:

• Prevents excessive fetlock extension during weight-bearing
• Absorbs high concussive forces
• Stabilizes the distal limb during athletic loading

Hindlimb proximal suspensory injuries are particularly common in disciplines requiring propulsion, collection, and repetitive load cycles. These cases often require a structured equine ligament rehabilitation approach.

Types of Suspensory Ligament Injuries

Suspensory pathology can present in several forms:

Proximal Suspensory Desmitis (PSD)
Inflammation or fiber disruption near the ligament origin, often deep and difficult to detect early.

Branch Lesions
Partial tearing or fiber degeneration in the medial or lateral branches near the fetlock.

Acute Fiber Strain
Sudden overload injury during athletic effort.

Chronic Degeneration
Repetitive micro-trauma leading to fiber disorganization and reduced elasticity.

Because ligament tissue remodels slowly, structured support strategies are often integrated into long-term management plans.

Why Suspensory Injuries Are Difficult to Manage

Several factors make suspensory injuries challenging:

• Limited direct blood supply compared to muscle
• Dense collagen fiber structure
• High mechanical load during movement
• Deep anatomical placement (especially proximally)
• Elevated risk of re-injury

These characteristics make circulation support and organized collagen remodeling essential considerations during recovery.

How Red and Infrared Light Interact With Ligament Tissue

Photobiomodulation works at the cellular level.

Specific wavelengths of red and near-infrared light are absorbed by chromophores within mitochondria, particularly cytochrome c oxidase. This interaction may support:

• Increased ATP (cellular energy) production
• Improved cellular metabolism
• Modulation of inflammatory signaling
• Fibroblast activity and collagen organization
• Microcirculatory support

In ligament tissue, proper collagen alignment is critical for restoring tensile strength.

Learn more about how 660nmm 850nm and 940nm wavelengths interact with equine tissue

Wavelength Strategy for Suspensory Support

Different wavelengths interact with equine tissue at different depths. Using a combination of red and near-infrared light allows therapy to support both surface circulation and deeper ligament structures.

660nm – Red Light

Supports superficial circulation and tissue oxygenation near the skin and soft tissue layers. This wavelength is commonly used to help stimulate cellular metabolism and improve local blood flow.

850nm – Near Infrared

Penetrates deeper into connective tissue and is commonly used when addressing tendons, ligaments and joint structures in the lower limb.

940nm – Advanced Near Infrared

Penetrates further into dense connective structures and is often selected when addressing deeper anatomical regions such as proximal suspensory ligament attachments where tissue density and mechanical load are highest.

Layering wavelengths allows multi-depth support within a single session rather than focusing only on superficial structures

Ligament tissue is composed primarily of organized collagen bundles designed to withstand tensile force. Supporting structured collagen remodelling, rather than simply reducing surface inflammation. This is a key consideration in performance horses returning to work.

Acute vs Chronic Suspensory Support Approaches

Light therapy should always be integrated within a veterinary-guided rehabilitation plan.

Acute Phase (Recent Injury)

Goals:
• Support inflammatory regulation
• Assist circulation
• Complement controlled rest protocols

Typical approach:
• Shorter sessions
• Increased frequency early on
• Used after acute heat stabilizes

Chronic Phase (Long-Term or Recurrent)

Goals:
• Encourage structured tissue remodeling
• Support circulation to dense ligament tissue
• Assist progressive return-to-work programs

Typical approach:
• Moderate session duration
• Consistent structured schedule
• Integrated alongside strengthening exercises

Consistency is generally more important than intensity in ligament support routines.

Product Selection for Suspensory Ligament Support

The location and depth of injury influence device selection.

Leg Wraps

Provide circumferential coverage for mid-cannon suspensory and branch regions.

Stifle Wrap
May be used for proximal hindlimb suspensory regions where deeper placement is required.

8" x 21" Infrared Pad
Allows localized placement directly over specific lesion sites.

Selecting the correct device ensures appropriate coverage without repositioning gaps.

Common Questions About Suspensory Ligament Light Therapy

Can red light therapy help suspensory ligament injuries in horses?

Light therapy may support circulation and cellular metabolism as part of a structured rehabilitation plan. It should not replace veterinary diagnosis or controlled exercise management.

How long should infrared therapy be used for suspensory injuries?
Protocols vary based on severity and phase. Acute cases often involve shorter, more frequent sessions, while chronic conditions benefit from consistent long-term scheduling.

Is 940nm useful for ligament injuries?
Deeper near-infrared wavelengths are commonly selected when addressing dense connective tissue structures such as ligaments.

Can light therapy replace rest?
No. Suspensory injuries require structured rest, controlled loading, and veterinary oversight. Light therapy is considered a supportive modality.

Clinical Considerations and Responsible Use

• Always obtain veterinary evaluation before beginning rehabilitation.
• Do not use over known tumors.
• Avoid treating uncontrolled swelling or infection without guidance.
• Integrate therapy into a structured conditioning plan.

Responsible integration produces the most consistent outcomes.

Learn More About Equine Light Therapy

If you want a deeper understanding of how red and near-infrared light interacts with equine tissue, explore the following resources:

• Wavelength Science – Learn how 660nm, 850nm, and 940nm wavelengths interact with equine tissue at different depths.

• Red Light Therapy Usage & Applications Guide – Practical guidelines for session timing, treatment frequency, and structured therapy routines.