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TPLO or TTA?

How the two most common CCL surgeries differ, and what published studies found when they compared them.Published Sources checked 11 sources

If your vet has found a torn cranial cruciate ligament (CCL), the knee injury behind most dog “ACL” surgeries, you'll probably hear two names: TPLO and TTA. Both are bone-cutting surgeries that change how the knee works, so it stays stable without the torn ligament [1]. They work differently, and the studies comparing them don't all agree.

This page explains the difference and summarizes what published studies found. It isn't veterinary advice. Which surgery suits your dog is a decision for you and your surgeon, based on an exam and X-rays.

At a glance

Full name
TPLOTibial plateau leveling osteotomyTTATibial tuberosity advancement
The cut
TPLOA curved cut around the top of the shin bone, which is rotated [1]TTAA straight cut along the front of the shin bone, which is moved forward [1]
What holds it
TPLOA bone plate and screws [1]TTAA wedge, a bone plate and screws [1]
Aim
TPLOLevel the top of the shin bone to about 90° to the thigh muscle's pull [2]TTAMove the muscle's attachment until its pull is about 90° to the top of the shin bone [2]
Surgeons who prefer it for dogs over 33 lb
TPLO147 of 187 surveyed (78.6%) [3]TTA26 of 187 surveyed (13.9%) [3]
Colorado surgeons listed here
TPLO58TTA9

Surgeon counts are this directory's current listings. A clinic whose own website doesn't name a procedure isn't counted.

How each works

TPLO

TPLOA curved cut around the top of the shin bone. The top is rotated until it is close to level, then held with a plate and screws.Thigh boneKneecapShin boneTop leveledCurved cutPlate and screws

TTA

TTAA straight cut along the front of the shin bone. The front strip is moved forward, a wedge holds the gap open, and a plate and screws hold it in place.Thigh boneKneecapShin boneWedgeFront movedforwardStraight cutPlate and screws
A dog's knee from the side, front of the leg to the left. Simplified and not to scale. Dashed blue lines show where the bone is cut.

TPLO

The top of the shin bone (the tibial plateau) slopes backward, so when a dog puts weight on the leg, the thigh bone tends to slide down that slope. The cruciate ligament normally stops that slide. In a TPLO, the surgeon makes a curved cut around the top of the shin bone, rotates that piece until the surface is close to level, and fixes it with a plate and screws [1, 2]. With a level surface, the thigh bone no longer slides, so the knee is stable without the ligament.

Colorado State University's veterinary hospital says it generally prefers TPLO [2].

TTA

TTA changes the knee's mechanics from the front instead. The surgeon makes a straight cut along the front of the shin bone and moves that strip of bone (the tibial tuberosity, where the kneecap tendon attaches) forward. A spacer, or “cage”, holds the gap open, secured with a plate and screws [1]. Moving the attachment forward changes the angle of the thigh muscle's pull until it counteracts the sliding force [2].

What the research says

The research comparing the two is limited. Most studies are small, many look back at past cases instead of following dogs forward, and there are few randomized trials [4]. Read each finding below with that in mind.

Both surgeries work

A 2022 review of 72 studies concluded that TPLO and TTA are both effective and restore function for most dogs [4]. The reviewers found no clear reason to recommend one over the other overall [4]. The American College of Veterinary Surgeons reports significant improvement after cruciate surgery in 85 to 90% of cases [1].

Complication rates were similar

In the same review, the average complication rate was about 20% for TPLO and about 22% for TTA [4]. TPLO had a lower rate of surgical site infection [4]. In both surgeries, larger dogs had more complications [4]. One surgeon's series of 1,000 consecutive TPLO dogs recorded a 14.8% complication rate, 6.6% of them major [5].

Some studies favored TPLO for a full return to function

One study measured how much weight dogs put on each leg. TPLO dogs matched normal dogs at both a walk and a trot by 6 to 12 months. TTA dogs matched normal dogs at a walk by 12 months, but not at a trot [6]. The groups were small, with 15 TPLO dogs and 14 TTA dogs.

A second study looked back at past cases. In it, more TPLO dogs than TTA dogs reached full function more than a year after surgery, and TTA had higher rates of major complications and later meniscal tears [7]. It included 65 TPLO dogs but only 18 TTA dogs.

Meniscal tears after surgery

The meniscus is a cartilage cushion inside the knee that can tear after surgery. In a laboratory study on beagles, where each dog had TTA on one knee and TPLO on the other, new meniscal tears were more common after TTA [8]. Those were purpose-bred research dogs whose ligaments were cut for the study, not pets with natural injuries, so the results may not carry over directly.

The first days may be easier after a newer TTA technique

In a small randomized trial of 26 dogs, dogs that had a modified TTA (“TTA Rapid”) limped less in the first three days than TPLO dogs, and the surgery took less time. By six months there was no difference between the groups [9].

Arthritis develops either way

Arthritis usually keeps progressing after cruciate surgery, though more slowly than without surgery [1]. The 2022 review found lower arthritis scores after TTA in the short to medium term, but all dogs developed at least mild arthritis in the long term [4].

What surgeons weigh

The sources describe several factors that can lead a surgeon to suggest one surgery over the other. They help you follow your surgeon's reasoning, but they can't make the choice for your dog.

Size and activity

Many surgeons prefer bone-cutting surgeries such as TPLO for large, active dogs, and some use TPLO for dogs of all sizes [1].

The slope of the shin bone

Small dogs, under about 33 lb, often have a steep slope at the top of the shin bone [10]. Whether TTA suits dogs with a steep slope is debated [10]. Ask your surgeon what your dog's slope is.

A kneecap problem as well

Some dogs, often small ones, have a kneecap that slips out of place (luxating patella) as well as a torn ligament. Surgeons can combine a cruciate repair with a procedure that realigns the kneecap. One study describes a combined TTA technique for dogs under about 26 lb [11].

The other knee

Between 40% and 60% of dogs with this injury in one knee later develop it in the other [1]. Your surgeon may examine both knees.

What the surgeon usually does

In a survey of 187 orthopedic surgeons, most preferred TPLO for dogs over 33 lb, whether or not they were board-certified [3]. Individual surgeons still differ in what they prefer and in how often they do each surgery, so it's fair to ask.

Questions to ask your surgeon

  1. 1.Which surgery do you recommend for my dog, and why?
  2. 2.What is my dog's tibial plateau angle, and does it affect the choice?
  3. 3.How many of each surgery do you perform a year?
  4. 4.What complications do you see most often, and how are they handled?
  5. 5.Will you check the meniscus during surgery?
  6. 6.What does recovery look like: how long on a leash, and when can my dog run again?
  7. 7.Does my dog's other knee show any signs of the same problem?

Where to find each in Colorado

Or browse by city. Every listing shows what the clinic's own website says and when we last checked it. How we check.

Sources

  1. 1.American College of Veterinary Surgeons. Cranial Cruciate Ligament Disease (CCL). Owner information page. acvs.org/small-animal/cranial-cruciate-ligament-disease/
  2. 2.Colorado State University Veterinary Health System. Canine cruciate ligament injury. December 14, 2020. csuveterinaryhealth.org/canine-cruciate-ligament-injury/
  3. 3.von Pfeil DJF, Kowaleski MP, Glassman M, Dejardin LM. Results of a survey of Veterinary Orthopedic Society members on the preferred method for treating cranial cruciate ligament rupture in dogs weighing more than 15 kilograms (33 pounds). J Am Vet Med Assoc. 2018;253(5):586-597. doi.org/10.2460/javma.253.5.586
  4. 4.Wemmers AC, Charalambous M, Harms O, Volk HA. Surgical treatment of cranial cruciate ligament disease in dogs using tibial plateau leveling osteotomy or tibial tuberosity advancement: a systematic review with a meta-analytic approach. Front Vet Sci. 2022;9:1004637. doi.org/10.3389/fvets.2022.1004637
  5. 5.Fitzpatrick N, Solano MA. Predictive variables for complications after TPLO with stifle inspection by arthrotomy in 1000 consecutive dogs. Vet Surg. 2010;39(4):460-474. doi.org/10.1111/j.1532-950X.2010.00663.x
  6. 6.Krotscheck U, Nelson SA, Todhunter RJ, Stone M, Zhang Z. Long term functional outcome of tibial tuberosity advancement vs. tibial plateau leveling osteotomy and extracapsular repair in a heterogeneous population of dogs. Vet Surg. 2016;45(2):261-268. doi.org/10.1111/vsu.12445
  7. 7.Christopher SA, Beetem J, Cook JL. Comparison of long-term outcomes associated with three surgical techniques for treatment of cranial cruciate ligament disease in dogs. Vet Surg. 2013;42(3):329-334. doi.org/10.1111/j.1532-950X.2013.12001.x
  8. 8.Jeong J, Jeong SM, Kim SE, Lewis DD, Lee H. Subsequent meniscal tears following tibial tuberosity advancement and tibial plateau leveling osteotomy in dogs with cranial cruciate ligament deficiency: an in vivo experimental study. Vet Surg. 2021;50(5):966-974. doi.org/10.1111/vsu.13648
  9. 9.Livet V, Baldinger A, Viguier É, et al. Comparison of outcomes associated with tibial plateau levelling osteotomy and a modified technique for tibial tuberosity advancement for the treatment of cranial cruciate ligament disease in dogs: a randomized clinical study. Vet Comp Orthop Traumatol. 2019;32(4):314-323. doi.org/10.1055/s-0039-1684050
  10. 10.Brioschi V, Arthurs GI. Cranial cruciate ligament rupture in small dogs (<15 kg): a narrative literature review. J Small Anim Pract. 2021;62(12):1037-1050. doi.org/10.1111/jsap.13404
  11. 11.Hackett M, St Germaine L, Carno MA, Hoffmann D. Comparison of outcome and complications in dogs weighing less than 12 kg undergoing miniature tibial tuberosity transposition and advancement versus extracapsular stabilization with tibial tuberosity transposition for cranial cruciate ligament disease with concomitant medial patellar luxation. Vet Comp Orthop Traumatol. 2021;34(2):99-107. doi.org/10.1055/s-0040-1719118

This page summarizes published sources and isn't veterinary advice. Your vet knows your dog.