🐴 Upward Fixation of the Patella in Horses: Diagnosis, Treatment & Surgery in 2025 🦵🧠

By Dr Duncan Houston BVSc

“Stifled” is a term many horse owners use when their horse suddenly can’t move a hind leg—but the more accurate term is upward fixation of the patella. This condition occurs when the horse’s kneecap becomes trapped above the femur, locking the stifle joint and making it impossible to flex the leg. In 2025, treatment has come a long way, with effective, low-risk surgical techniques and improved understanding of causes and prevention. 🐎🧠

🧠 What Is Upward Fixation of the Patella?

This condition involves the horse’s patella (kneecap) catching on the lower end of the femur, preventing the stifle (equivalent to the human knee) from flexing. This results in the horse appearing as if one hind leg is locked behind the body. The joint can stay stuck for several seconds—or longer. 🦵

🔍 Who’s Affected?

This condition is most common in:

• 🐎 Ponies and miniature horses
• 📏 Horses with straight hind limb conformation
• 🏠 Horses kept in low exercise environments
• 📉 Horses with poor hind limb muscle tone

Inactive horses are particularly at risk because decreased muscle support allows the patella to become more mobile and prone to catching. 🧘‍♂️

📋 Signs of Upward Fixation

Classic signs include:

• 🚷 Sudden inability to flex a hind leg
• 🐢 A locked or extended hind limb that drags behind the horse
• 🔁 Occasional “clicking” as the kneecap catches and releases
• 🎯 A hind leg that suddenly “pops” free with a jerk

The condition may come and go, especially in the early stages, making diagnosis by a vet essential. 🎯

🩺 Diagnosis

Diagnosis is typically based on clinical signs and observation. Flexion tests, gait evaluation, and palpation help confirm the diagnosis. In advanced or chronic cases, imaging (e.g., ultrasound) may be used to assess ligament integrity. 🧠📸

🛠️ Treatment Options in 2025

There are several approaches depending on severity and age of the horse:

🔹 Conservative Management

• 🏋️ Strength-building exercises for hind limb muscle tone
• 🚶 Consistent turnout or light work to maintain motion
• 🧬 Nutritional support, including joint supplements and muscle-building nutrients

🔹 Injections

• 💉 Pro-inflammatory substances (e.g., iodine) injected into the ligament to stimulate thickening and reduce patella mobility

This method can work for mild to moderate cases but may require multiple treatments. 📆

🔪 Surgical Treatment Options

Historically, upward fixation was treated with full patellar ligament transection, which was effective but had a high rate of complications—including damage to the patella itself. 🏥

Now, two modern surgical options offer much better outcomes:

✅ Stab Incision (Patellar Ligament Splitting)

• ✂️ Small incisions are made along the patellar ligament using a blade
• 🧠 Stimulates healing and controlled thickening without fully cutting the ligament
• 📊 In a study from Copenhagen, 97% of horses improved with no post-op complications

This approach is now a go-to option for horses that don’t respond to conservative care. 🏆

✅ Full Patellar Ligament Transection (Only in Severe Cases)

• 🚨 Used only if all other treatments fail
• 🛌 Requires strict rest for at least 8 weeks to prevent patella damage

While effective, this procedure is rarely used today due to the success of less invasive options. ⚠️

📆 Recovery Timeline

Depending on the treatment:

• 💪 Conservative exercise: gradual improvement over 4–8 weeks
• 💉 Injection: response in 2–4 weeks, may need repeating
• 🔪 Surgery (stab incision): recovery within 4–6 weeks with controlled rehab

🧠 Prevention Tips

To reduce the risk of upward fixation of the patella:

• 🧘 Keep horses fit and muscled, especially in the hind end
• 🏃 Avoid long periods of stall rest in at-risk horses
• 🦶 Work with your farrier to ensure balanced hind limb support

In young horses, gradually increasing turnout and exercise often prevents the issue from developing. 🐣

📲 Ask A Vet for Gait & Stifle Support

If your horse drags a leg, “locks up,” or shows unusual hind limb movement, visit AskAVet.com or use the Ask A Vet App for real-time support and video gait evaluation. 📱🐎

Dr Duncan Houston and the team can help determine if your horse needs exercise, injections, or surgery—and help track recovery safely. 🧠💬

🏁 Final Thoughts

Upward fixation of the patella is surprisingly common, especially in ponies, minis, and under-conditioned horses. In 2025, with effective surgical options like stab incisions and smart muscle-building strategies, most horses recover fully and return to performance. 🐴❤️

Suspect patellar locking? Visit AskAVet.com and get your horse back on the move 🐎🦵