Key Insights
  • Arthroscopy is a minimally invasive surgical technique that allows direct visualization and treatment of joint structures in horses
  • Used to diagnose and treat joint disorders such as OCD, osteoarthritis, synovitis, and ligament injuries
  • Involves inserting a small camera and instruments through tiny incisions to remove fragments or repair tissue
  • Offers reduced soft tissue trauma, faster healing, and lower infection risk compared to open joint surgery
  • Requires general anesthesia and careful postoperative care including stall rest, bandaging, and gradual exercise
  • Complications are rare but can include infection, nerve injury, or synovitis during recovery

Joint disease and injury are common causes of lameness and poor performance in horses, particularly in athletic or young, growing animals. Conditions such as osteochondritis dissecans (OCD), synovitis, and traumatic fractures of joint surfaces can significantly affect a horse’s comfort, movement, and long-term soundness.

Arthroscopy has become the gold standard for addressing these issues because it allows the surgeon to assess the joint directly, rather than relying solely on imaging techniques such as radiographs or ultrasound. This procedure involves inserting a small camera and specialized instruments through tiny incisions to visualize, diagnose, and treat problems inside the joint.

Arthroscopy offers many advantages over traditional surgical techniques. Small incisions associated with the procedure reduce soft tissue trauma, postoperative pain, and infection risk. Arthroscopy also carries faster healing times with minimal scarring compared to more invasive methods.

As equine athletes continue to push the boundaries of performance, maintaining joint health has become a top priority in both prevention and treatment. Arthroscopy represents a key advancement in this effort, combining precision, safety, and effectiveness to support better long-term outcomes for horses of all disciplines.

Arthroscopy for Horses

Arthroscopy is a minimally invasive surgical procedure that allows direct visualization of the inside of a horse’s joint using a small camera which transmits real-time images to a monitor. By making multiple small incisions, specialized instruments can be inserted at the joint site to remove loose fragments, smooth damaged cartilage, or perform other delicate procedures.

Arthroscopy can be used for diagnosis and treatment of joint problems in horses. As a diagnostic tool, arthroscopy allows the veterinarian to evaluate the cartilage, bone, and soft tissues making up a joint. [1]

Arthroscopy is used to diagnose numerous conditions, including: [1]

In most cases, these conditions are strongly suspected based on the results of other diagnostic tests, including physical examination, X-rays, ultrasound, MRI, or CT. [2] Arthroscopy allows for definitive diagnosis of these conditions in cases where the other diagnostic modalities are inconclusive. [2]

During treatment, surgeons can remove damaged tissue and fragments of cartilage or bone to restore normal joint function. Arthroscopy is most commonly used to treat osteochondral fragments from osteochondritis dissecans, but the other conditions listed above can also benefit from arthroscopy. [1]

Equipment

The main piece of equipment for arthroscopy is an endoscope, a rigid tube with a camera or optical unit on the end that the surgeon inserts into the joint. [1] Most endoscopes used for arthroscopy in horses are under 4 mm in diameter. [1]

The endoscope transmits the image to an eyepiece or external monitor for the surgeon to view. [3] The endoscopy unit also has a light source to illuminate the tissue for visualization. [1]

The rigid tube that makes up the endoscope is hollow, allowing the surgeon to introduce fluid or gas into the joint capsule. [1] This helps clean tissue surfaces, remove bleeding, and pressurize the joint capsule to maximize visibility. [1]

If using arthroscopy for treatment, the surgeon introduces surgical tools into a second incision in the joint space. [1] Instruments may include forceps, bone curettes, blades, or probes. [1]

Procedure

Most surgeons perform arthroscopy while the horse is under general anesthesia. After anesthetizing the horse and moving them into the surgical suite, they begin preparing the skin for the procedure.

Depending on the location of the surgery and surgeon preference, skin preparation may include clipping or shaving the hair. [2] The veterinary team scrubs the skin with antiseptics like povidone iodine or chlorhexidine to remove any bacterial contamination on the skin surface. [2]

Once the skin is clean, the veterinary team places waterproof drapes around the surgical site. These drapes help prevent contamination of the surgical site during the procedure. [2]

The surgeon makes an initial incision near the joint and inserts the arthroscope. They use fluid or gas to inflate the joint capsule, making it easier to maneuver instruments within the joint space. [2]

Depending on visibility, the surgeon may have to flush the joint by introducing fluid and allowing it to drain out of a second incision or a needle placed through the skin. [2] This process removes any material that may prevent assessment of the joint tissues.

Once the joint space is clean, the surgeon begins evaluating the joint for any changes that may cause lameness. After the evaluation is complete, the surgeon may proceed with treatment depending on their findings.

Treatments may include: [2]

  • Removal of bone or cartilage fragments
  • Debriding (removing) tissue to promote proper healing
  • Lavage (flushing) of the joint to remove infectious or inflammatory material
  • Reconstruction of the joint surface

Following treatment, the surgeon closes the incisions in the skin using sutures. The surgical drapes are removed, and the limb is bandaged before the horse is aroused from general anesthesia.

Interpreting Results

Arthroscopy allows surgeons to visually assess a joint’s integrity, rather than relying on other diagnostic tools that may not reveal the true extent of damage.

Features of the joint they observe include: [2]

  • Joint fluid
  • Joint membrane
  • Joint capsule and ligaments
  • Cartilage and bone

Joint Fluid

Joint fluid is typically clear, yellow-tinged, and viscous (thick). It should not contain any debris or fragments. [2]

During arthroscopy, red-tinged joint fluid can indicate recent or reoccurring tissue disruption, resulting in bleeding into the joint space. Fragments or debris may indicate breakdown of the cartilage or bone. [2]

Joint Membrane

The synovium (joint membrane) produces joint fluid to ensure proper lubrication of the joint. It has characteristic villi (finger-like projections) on its inner surface. [2] Synovial villi react to damage within the joint by changing their color, density, and thickness. Surgeons can interpret these changes to make a diagnosis.

Common changes in the synovium include: [2]

  • Hyperemia: Reddening of the villi indicating inflammation.
  • Petechiation: Pinpoint red dots on the villi where small blood vessels have enlarged, indicating inflammation.
  • Thickening: Swelling of the villi due to edema (fluid accumulation), suggestive of inflammation.
  • Density changes: Coalescing or clumping of the villi can be a response to inflammation, as the body attempts to produce more joint fluid to maintain lubrication. Damaged villi may also develop scar tissue, forming dense mats.

Joint Capsule & Ligaments

The joint capsule is a layer of connective tissue that contains the joint fluid. Areas of high strain thicken to form a ligament, a more robust cord of connective tissue within the joint capsule. [2]

The joint capsule or its associated ligaments may tear or rupture, which can be identified on arthroscopy in some cases. [2]

Cartilage & Bone

The bones making up each joint are lined with a layer of cartilage, which helps provide a smooth, low-friction surface for joint movement. Arthroscopy allows the surgeon to evaluate the cartilage and edges of the bones to identify any changes.

Common findings include: [1][2]

  • Osteophytes: Areas of bone proliferation at the edge of a joint, indicating arthritis.
  • Enthesophytes: Bone proliferation where a ligament or tendon inserts onto the joint, indicating inflammation, previous ligament damage, and/or arthritis.
  • Fibrillation: Irregularity in the cartilage surface producing waves, small craters, or linear erosions. Often indicates that there is a loose fragment within the joint space that is interfering with joint movement.
  • Eburnation: Areas where the cartilage is completely worn away, revealing underlying bone. This typically results from chronic arthritis.
  • Fragments: Can result from osteoarthritis or osteochondritis dissecans. These pieces break off from the bone or cartilage and float within the joint fluid, interfering with joint movement and increasing friction.

Preparing Your Horse for Arthroscopy

There are no specific steps needed to prepare your horse for arthroscopy, as most of the preparation is handled by the veterinary team once your horse arrives at the surgical center. Your veterinary surgeon can walk you through the preparation steps they undertake for your horse’s specific procedure.

After the procedure, your horse will have a postoperative care plan to ensure appropriate healing. The extent of aftercare depends on the joint involved, invasiveness of the procedure, and other factors. [1]

Common components of postoperative care for arthroscopy include: [1]

Depending on surgeon preference, available facilities, and other factors, the initial recovery period may occur at the clinic or at home. Some surgeons may refer you to surgical recovery boarding facilities or rehabilitation facilities for ongoing management.

If your horse has undergone treatment, your surgeon may recommend a rehabilitation program to bring your horse back into work once their surgery site heals. They may also recommend intra-articular (into the joint) treatments for several weeks to help boost cartilage healing and reduce inflammation. [1]

A rehabilitation plan after arthroscopy may involve: [4]

  • Stall rest with hand grazing only for up to 2 weeks
  • Gradually introducing and increasing hand-walking exercise over a period of 6 weeks
  • Turnout in a small paddock and a gradual return to under saddle work

During the recovery period, you should monitor for any swelling, discharge from the surgical site, fever, or lameness. Contact your horse’s surgical team if there are any signs of pain or other complications. [4]

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Complications

Although arthroscopy is a safe and effective procedure, it comes with a risk of intraoperative (during the surgery) and postoperative (during recovery) complications. Significant complications are rare for this procedure.

Intraoperative Complications

The most common intraoperative complications in arthroscopy are: [5]

  • Iatrogenic damage
  • Foreign material in the joint capsule

Iatrogenic Damage

Iatrogenic damage refers to tissue injury caused by the surgeon during the surgery. It most commonly occurs due to aggressive technique, movement of the horse during surgery due to inadequate sedation or anesthesia, or poor visualization of the tissue during the procedure. [6]

If iatrogenic damage is identified, the surgeon treats the injury and reports the damage to the client. The prognosis depends on the extent of the damage, post-operative care, and other factors. To prevent iatrogenic injury, surgeons are trained in gentle techniques and optimal tool handling. They also ensure appropriate sedation/anesthesia during the procedure.

Foreign Material

Foreign material within the joint capsule can occur due to breakage of instruments or from pieces of drape, hair, skin, or adhesive entering the surgical incision. [5] In most cases, these fragments can be flushed out of the joint during the surgery.

Surgical instruments can break accidentally from interference between tools within the joint space or from movement of the horse during the procedure. Surgeons are trained in tool handling techniques to minimize the risk of interference. If an instrument does break, surgeons use endoscopy, radiographs, or ultrasound to locate the fragment for removal. [6]

Postoperative Complications

Postoperative complications associated with arthroscopy include: [5]

  • Neuropathy or myopathy
  • Surgical site infection
  • Synovitis

Neuropathy or Myopathy

Following general anesthesia, horses may be unable to use their limb or limbs properly due to damage to the muscles or nerves. [6] Typically these conditions result from inadequate padding on the surgical table causing pinching or compression of the tissue. [6]

Prognosis depends on the severity of the injury. Most horses regain normal function within 10-14 days after the procedure. If there are still deficits present, such as difficulty moving a limb, after 14 days, the prognosis for full return to function is poor. [6]

Surgical Site Infection

Surgery creates the opportunity for bacteria to enter the body, potentially resulting in infection. To reduce the risk of infection, surgeons use aseptic technique to minimize the risk of bacteria entering the wound. They may also place the horse on antibiotics after the surgery to prevent infection from developing. [6]

The prognosis for surgical site infections depends on the location of the infection. Infections in the skin typically resolve rapidly with appropriate treatment.

Septic arthritis, bacterial infection of the joint, is a more severe complication that requires intensive treatment. [6]This condition is uncommon after arthroscopy, occurring in around 1% of surgeries. [7] Treatment for this condition may involve antibiotics, flushing of the joint, regional limb perfusion, and more. [5]

The prognosis for this condition can be poor, as bacterial infection causes significant damage to the joint tissues.

Synovitis

Some horses undergoing arthroscopy develop joint swelling after surgery. This swelling may last for more than 6 weeks. [6]

Synovitis usually indicates there is still disease present within the joint that was not completely treated by the procedure. [6] It can also develop if the horse resumes activity too quickly after surgery, resulting in low-grade inflammation within the joint. However, some horses develop idiopathic (unknown cause) synovitis that may persist for weeks to months. [6]

Treatment typically involves repeating the arthroscopy to remove any areas of diseased tissue that were missed or anti-inflammatory medication to reduce local inflammation. Idiopathic synovitis may resolve over time as the horse’s joint capsule reduces its increased production of joint fluid in response to the surgery. [6]

Prevention strategies include anti-inflammatories after the surgery and a gradual return to exercise.

Frequently Asked Questions

Here are some frequently asked questions about arthroscopy in horses:

Summary

Arthroscopy is a minimally invasive surgical technique that allows veterinarians to diagnose and treat joint problems in horses.

  • A small camera (arthroscope) is inserted into the joint to give the surgeon a clear, real-time view of cartilage, bone, and soft tissues.
  • The procedure is commonly used to remove bone chips, address OCD lesions, treat synovitis, and repair cartilage damage caused by injury or wear.
  • Arthroscopy involves smaller incisions than traditional surgery, leading to less pain and faster healing.
  • This approach allows for both diagnosis and treatment in a single procedure, improving outcomes.
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References

  1. Ross. M. W. and Dyson. S. J. Diagnosis and Management of Lameness in the Horse. 2nd ed. Elsevier Saunders, St. Louis, Mo. 2011.
  2. MacIlwraith. C. W. et al. Diagnostic and Surgical Arthroscopy in the Horse. Fourth edition. Mosby, St. Louis. 2015.
  3. Abutarbush. S. and Carmalt. J. Equine Endoscopy and Arthroscopy for the Equine Practitioner. Teton NewMedia, New York. 2008.
  4. Gasiorowski. J. C. and Richardson. D. W. Diagnostic and Therapeutic Arthroscopy in the Standing Horse. Veterinary Clinics of North America: Equine Practice. 2014.
  5. Goodrich. L. R. and McIlwraith. C. W. Complications Associated with Equine Arthroscopy. Veterinary Clinics of North America: Equine Practice. 2008.
  6. Rubio-Martinez. L. M. and Hendrickson. D. A. Complications in Equine Surgery. Wiley Blackwell, Hoboken. 2021.
  7. Olds. A. M. et al., Evaluation of the Rate of Development of Septic Arthritis after Elective Arthroscopy in Horses: 7 Cases (1994–2003). Journal of the American Veterinary Medical Association. American Veterinary Medical Association. 2006.