Dogs, like people, can injure ligaments in their knee joints (stifles). In dogs, the ligament most often affected is the cranial cruciate ligament (CCL). In people, this same structure is called the anterior cruciate ligament (ACL). Because many pet parents recognize the term ACL, veterinarians often use both names to avoid confusion.
How Cranial Cruciate Ligament Injuries Occur in Dogs
In some dogs, a cranial cruciate ligament injury occurs suddenly. For example, a dog may rupture the ligament after a sharp change in direction while running or playing—similar to a human athlete pivoting during sports.
More commonly, CCL disease develops gradually. Chronic inflammation and progressive ligament degeneration weaken the ligament over time rather than a single traumatic event causing failure. As a result, approximately 50% of dogs diagnosed with a CCL injury in one knee will later develop disease in the opposite knee.
Diagnosing Cranial Cruciate Ligament Injury in Dogs
Veterinarians typically diagnose cranial cruciate ligament injury without difficulty.
First, the veterinarian performs a thorough physical examination. This includes observing your dog’s gait and carefully palpating the affected knee. In some cases, the veterinarian recommends brief, light sedation to relax the surrounding muscles and keep the patient comfortable during the exam.
Key Diagnostic Tests
Veterinarians assess joint stability using:
- The cranial drawer test
- The tibial thrust (cranial tibial compression) test
These tests identify abnormal forward movement of the tibia relative to the femur, which indicates loss of ligament function.
Imaging Studies
- Radiographs (X-rays) help identify joint effusion, osteoarthritis, or other conditions such as bone tumors.
- Veterinarians may recommend advanced imaging (CT or MRI) in select cases.
- Arthroscopy allows direct visualization of the ligament and evaluation of the medial meniscus, which commonly sustains injury alongside the CCL.
Treating Cranial Cruciate Ligament Injury in Dogs
After confirming a cranial cruciate ligament rupture, veterinarians typically recommend prompt stabilization of the knee. Early intervention reduces pain, limits meniscal damage, and slows the progression of arthritis.
Treatment options include surgical and non-surgical approaches.
Surgical Options for Cranial Cruciate Ligament Repair
Extra-Capsular Suture Stabilization
Veterinarians also refer to this technique as the lateral fabellar suture or “fishing line” procedure. Surgeons place a strong synthetic suture outside the joint to mimic the stabilizing function of the ruptured ligament. Over time, scar tissue forms and contributes additional joint stability.
Veterinarians most often recommend this procedure for:
- Small-breed dogs
- Dogs with lower activity levels
Surgeons generally avoid this technique in large and giant breeds.
TightRope® Procedure
The TightRope® technique uses FiberTape®, a high-strength, Kevlar-like material. During surgery, the surgeon drills precisely positioned tunnels through the femur and tibia, passes the FiberTape® through them, and secures it with toggle buttons. The surgeon then tensions the implant until the knee feels stable on palpation.
Surgeons base their recommendation on:
- Dog size
- Age
- Activity level
- Tibial plateau angle
Bone Anchor / FiberWire® Technique
This method represents another form of extra-capsular stabilization. The surgeon places a small bone anchor and a multi-strand orthopedic suture (FiberWire®) to recreate the stabilizing role of the cranial cruciate ligament. As with other suture-based techniques, long-term stability depends on scar tissue formation.
Tibial Plateau Leveling Osteotomy (TPLO)
TPLO remains one of the most commonly performed and extensively studied surgeries for cranial cruciate ligament disease. During the procedure, the surgeon makes a curved bone cut at the top of the tibia and rotates the tibial plateau to neutralize destabilizing forces within the knee.
The surgeon stabilizes the bone using a plate and screws while healing occurs. Most dogs retain these implants permanently unless complications develop.
Veterinarians often recommend TPLO for:
- Young, active dogs
- Dogs weighing more than approximately 18 kg (40 lb)
- Dogs with steep tibial plateau angles
Numerous studies demonstrate superior functional outcomes in large and giant breeds when compared with extra-capsular techniques.
Tibial Tuberosity Advancement (TTA)
TTA stabilizes the knee by advancing the tibial tuberosity forward, which reduces cranial tibial thrust during weight bearing. Surgeons may choose this option for dogs that do not qualify as ideal TPLO candidates or for those with additional orthopedic disease in the same knee.
Non-Surgical Management of Cranial Cruciate Ligament Injury
Non-surgical management includes:
- Activity restriction
- Weight optimization
- Anti-inflammatory medications
- Structured rehabilitation therapy
Although these strategies can improve comfort, they do not restore joint stability. Veterinarians typically reserve non-surgical management for dogs with low activity levels, significant medical conditions, or financial limitations.
Orthotics and Knee Braces
Custom knee braces may support recovery after surgery or provide comfort when surgery is not feasible. However, current evidence does not support orthotics as a consistent alternative to surgical stabilization.
Emerging Therapies for Cranial Cruciate Ligament Disease
Veterinary surgeons and rehabilitation specialists continue to investigate regenerative therapies, including:
- Platelet-rich plasma (PRP)
- Stem cell therapy
PRP originates from the patient’s own blood and delivers concentrated growth factors to damaged tissue. While these therapies may reduce inflammation and support healing, they do not replace mechanical stabilization of a ruptured ligament.
Key Take-Home Points About Cranial Cruciate Ligament Injury in Dogs
Selecting the most appropriate treatment for cranial cruciate ligament disease requires careful consideration. No single approach suits every dog. Size, age, activity level, anatomy, and concurrent disease all influence decision-making.
Consultation with a board-certified veterinary surgeon often provides valuable guidance. When rehabilitation plays a central role, collaboration with a veterinary sports medicine and rehabilitation specialist or a certified canine rehabilitation therapist (CCRT) can significantly improve outcomes.
Ultimately, the goal remains the same: restore comfort, mobility, and quality of life for each individual dog.
