Blog
 » 
TPLO
 » 
Zlig vs TPLO: Which Surgery Is Better for Dogs?

Zlig vs TPLO: Which Surgery Is Better for Dogs?

TPLO

X min read

Owners

Compare Zlig and TPLO surgeries for dogs to understand which is better for cruciate ligament injuries and recovery outcomes.

By 

Sustainable Vet Group

Updated on

August 13, 2026

.

This article is for informational purposes only and is not a substitute for professional veterinary advice. Every case is unique, so always consult your veterinarian for guidance specific to your pet.

This content is intended for veterinary professionals for educational purposes. It does not replace clinical judgment or tailored advice. Always rely on your training, expertise, and the specific context of your patients.

Zlig vs TPLO: Which Surgery Is Better for Dogs?

Zlig (STIF-VETLIG) is an intra-articular synthetic implant used to reconstruct the cranial cruciate ligament inside the joint a conceptually different approach from TPLO, which changes joint mechanics rather than replacing the ligament.

Both are valid surgical options for CCL rupture in dogs, and the evidence base for Zlig, while smaller than for TPLO, is growing.

 

Quick answer: Zlig replaces the torn CCL inside the joint using a synthetic fiber implant through small bone tunnels. A 107-case prospective study reported good to excellent results in 97 cases. TPLO has a much larger evidence base and is the ACVS first-choice for large dogs.

 

Key takeaways

  • Zlig reconstructs the CCL inside the joint using a synthetic fiber implant through small bone tunnels; TPLO changes joint geometry instead
  • A 107-case prospective study reported good to excellent results in 97 cases: the largest Zlig dataset, single-centre, without controlled TPLO comparison
  • TPLO has a significantly larger evidence base: 25+ years of RCTs and ACVS first-choice status for dogs over 60 lbs
  • Zlig requires only small bone tunnels, no osteotomy: bone-cutting complications such as delayed union are not relevant
  • Implant failure is the primary Zlig-specific risk: the synthetic ligament may stretch or fail over time in large or very active dogs
  • Zlig suits bilateral CCL cases in small to medium dogs: both knees can sometimes be addressed in one procedure

How Zlig works

Zlig stands for Z-Ligament. The procedure uses a synthetic fiber implant (marketed as STIF-VETLIG GLOBAL) placed intra-articularly inside the joint capsule to replace the torn CCL.

Unlike extracapsular techniques (lateral suture, Tightrope) which place material outside the joint, Zlig anatomically reproduces the CCL's position within the joint.

The procedure involves drilling small bone tunnels through the femur and tibia at the anatomical insertion points of the CCL.

The synthetic implant is passed through these tunnels and secured, providing immediate mechanical stability similar to the original ligament.

Because there is no bone cutting or tibial rotation, Zlig is less invasive than TPLO and significantly faster to perform.

Recovery may be faster in the early post-operative period for the same reason.

The hund-kreuzbandriss.de clinical commentary (German veterinary reference site) notes: TPLO is a fairly invasive technique that causes irreversible changes.

Intra-articular reconstruction with synthetic fibers only requires small bone tunnels, and complications from osteotomy when they occur are not always easy to correct.

Who makes the Zlig implant?

The Zlig system uses the STIF-VETLIG GLOBAL implant, manufactured in France.

The procedure was developed primarily in France and Germany. It is gaining awareness in other countries but remains far less available than the major TPLO systems.

The highly porous intra-articular fiber design promotes fibroblast penetration and collagen fiber ingrowth over time, which the manufacturers propose increases implant longevity by improving resistance to flexion and torsional forces.

What the evidence shows

Primary Zlig outcome study

A prospective study by Le Doze, Paris, and Pages (2012 to 2021, 107 cases) found good to excellent results in 97 of 107 cases.

The study was conducted at two veterinary clinics in France. This is the most comprehensive Zlig-specific outcome dataset in the veterinary literature.

The hund-kreuzbandriss.de review confirms: Reconstruction of the CCL using the intra-articular synthetic implant STIF-VETLIG GLOBAL leads to good to excellent results in 97 cases in this prospective study from 2012 to 2021.

Limitations of current Zlig evidence

  • The primary study is single-centre, non-randomized, and lacks a direct comparison control group
  • Long-term data beyond the study's follow-up period is limited
  • The procedure has not been evaluated in large-scale randomized controlled trials comparable to those available for TPLO and TTA
  • The evidence base is substantially smaller than for TPLO (25+ years of multi-centre data)

TPLO evidence in context

TPLO has been evaluated in prospective randomized studies, force plate gait analysis trials, and multi-year cohort studies across dozens of institutions.

The ACVS recommends TPLO as the most commonly performed procedure for dogs over 60 lbs based on this evidence base.

Zlig vs TPLO: key differences

FeatureZligTPLO
MechanismIntra-articular CCL reconstructionTibial geometry change
InvasivenessSmall bone tunnels; no osteotomyFull proximal tibial osteotomy
Surgery timeShorterLonger
Primary riskImplant stretch or failureBone healing complications
Best forSmall to medium dogs; bilateral casesLarge active dogs; steep TPA
Evidence baseGrowing but limitedExtensive (25+ years)
AvailabilityLimited; specialist-onlyWidely available at specialty centres
Osteotomy complicationsNot applicableRelevant (delayed union, TTF)

 

Patient selection

Zlig may be preferred when:

  • Small to medium breed dogs (primary candidate group in current evidence)
  • Bilateral CCL rupture in a small dog where simultaneous correction in one anaesthesia event is desired
  • Dog owner prefers to avoid the irreversible tibial changes of an osteotomy
  • The surgeon is specifically trained in the Zlig technique

TPLO is typically recommended when:

  • Dogs over 30 to 40 lbs, especially large and giant breeds
  • Dogs with steep tibial plateau angle (TPA) some are not suitable candidates for Zlig due to concurrent patellar luxation or excessive tibial ridge concavity
  • The ACVS first-choice recommendation is preferred, with the largest evidence base
  • General specialty practice context where Zlig expertise is not available

Hund-kreuzbandriss.de notes: dogs with a steep tibial plateau angle, concurrent patellar luxation, or excessive concavity of the tibial ridge are not good candidates for Zlig.

In these cases, TPLO represents an excellent and often the only alternative.

For the full surgical alternatives overview, see alternatives to TPLO surgery for dogs. For the TPLO vs Tightrope comparison, see Tightrope vs TPLO surgery for dogs.

Frequently asked questions

Is Zlig as effective as TPLO?

For small to medium dogs, the single-centre prospective study shows good to excellent results in the majority of cases.

A direct head-to-head randomized comparison with TPLO in matched patient populations has not been published, so direct effectiveness comparison is not currently possible.

TPLO has a much stronger and broader evidence base overall.

Can large dogs have Zlig surgery?

The current evidence base for Zlig is strongest in small to medium dogs. Large dogs generate higher joint forces that place more demand on the synthetic implant over time.

Many surgeons with Zlig experience reserve it for smaller patients, though there is no absolute size cutoff in the literature.

What happens if the Zlig implant fails?

The synthetic ligament can stretch or rupture over time. If this occurs, the stifle returns to instability and lameness.

Revision surgery would typically involve a different approach TPLO or TTA since the anatomy has not been altered by the Zlig procedure, making revision more straightforward than after an osteotomy.

How long does Zlig surgery take?

Shorter than TPLO in most cases, because no osteotomy is performed.

The exact duration varies by surgeon experience and patient anatomy, but the minimally invasive nature of the procedure is one of its practical advantages.

Where can I find a surgeon who performs Zlig?

Zlig is performed by veterinary surgeons specifically trained in the technique, primarily in France and Germany where the procedure was developed, and increasingly in other countries.

Board-certified veterinary orthopedic surgeons can advise whether the technique is available in your region.

Resources

  • Hund-Kreuzbandriss. Zlig Method: A Study. (Le Doze et al., 2012 to 2021 prospective study summary.) hund-kreuzbandriss.de
  • Hund-Kreuzbandriss. TPLO vs TTA vs ZLig vs Suture Retraction: 6 Methods. hund-kreuzbandriss.de
  • ACVS. Cranial Cruciate Ligament Disease. acvs.org
  • Vetamac. TPLO Surgery for Dogs: Success Rates and Alternative Options. vetamac.com

Get a Free Poster

Enhance your workspace with a high-quality radiographs reference poster, designed for veterinary professionals. This free physical poster will be shipped directly to you—just fill out the form to request your copy.

Things to know

Get a Free Poster for Your Clinic

Enhance your workspace with a high-quality radiographs reference poster, designed for veterinary professionals. This free physical poster will be shipped directly to you—just fill out the form to request your copy.

We'd love you to
Join Us!

Enter Your Details Below to Receive Your Information Pack

100% safe & secure. Your details are never shared or sold.

Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

Taking Great TPLO Radiographs

Click Below to Watch Live Video Demos

We'll send you a Free Wall Poster with all the steps

Now that you are a pro at TPLO rads

Let's take your infection control to the next level

Watch these videos!

Step #1

Getting Ready

Ensuring a clean surgical field starts with proper skin preparation. This video demonstrates the best practices for:

  • Shaving the patient – Achieving a close, even shave while minimizing skin irritation
  • The Dirty Scrub – The initial skin prep step to remove surface debris and reduce bacterial load before the sterile scrub.

Following these techniques helps reduce infection risk and improve surgical outcomes. Watch the video to see how it’s done effectively!

Step #2

Reduce Your Risks

Many surgeons are shocked to find out that their patients are not protected from biofilms and resistant bacteria when they use saline and post-op antibiotics.

That’s Where Simini Comes In.

Why leave these risks and unmanaged?  Just apply Simini Protect Lavage for one minute. Biofilms and resistant bacteria can be removed, and you can reduce two significant sources of infection.

Step #3

Take the Course

Preventing surgical infections is critical for patient safety and successful outcomes. This course covers:

  • Aseptic techniques – Best practices to maintain a sterile field.
  • ​Skin prep & draping – Proper methods to minimize contamination.
  • ​Antibiotic stewardship – When and how to use perioperative antibiotics effectively.

Stay up to date with the latest evidence-based protocols. Click the link to start learning and earn CE credits!

Get Your
Free Poster!

Enter your information below, and we’ll ship it to you at no cost.

Do you want to customize it?

How many would you like?

About you

Shipping information

100% safe & secure. Your details are never shared or sold.

We will work on your request shortly.
Oops! Something went wrong while submitting the form.
What’s your role in animal care?

Tell us who you are so we can guide you to the most relevant information.