Health guide

Patellar luxation:
realigning the joint with tibial tuberosity transposition

Patellar luxation is a common condition in dogs. Find out why an early orthopaedic opinion matters and how tibial tuberosity transposition corrects the alignment defect.

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Patellar luxation & tibial tuberosity transposition

A common condition that doesn't correct itself

Patellar luxation is a common condition in dogs, especially in small breeds, although it can also affect larger dogs.

The patella (kneecap) is a small bone at the front of the knee (stifle). As the leg moves, it must glide within a groove at the end of the femur. It is connected to the quadriceps muscle by a tendon, and to the upper part of the tibia by the patellar tendon.

For the knee to function properly, the quadriceps, the patella, the patellar tendon and their attachment point on the tibia must all be aligned.

When a patella luxates, this alignment is abnormal. The pull of the quadriceps then drags the patella towards the inside — or, less commonly, the outside — of the knee.

The dog may then briefly lift a hind leg for a few steps, before walking normally again once the patella returns to its position.

A condition that can get worse over time

Patellar luxation does not resolve on its own.

Rest, weight control or muscle strengthening can help maintain good physical condition, but in most cases they do not change the alignment of the patellar mechanism.

When the patella repeatedly slips out of its groove, the structures of the knee can gradually change. The tissues on one side of the patella contract, while those on the opposite side stretch. The patella can then become increasingly unstable and stay out of place for longer.

In growing dogs, deformities of the femur or tibia can also develop progressively.

Patellar luxation can also be associated with a cranial cruciate ligament rupture. Both conditions can coexist in the same knee and may require tailored management.

Seeing an orthopaedic vet

Patellar luxation doesn't necessarily need surgery in every case. Some mild forms can remain stable and simply be monitored.

Still, it's best not to wait until the dog's gait has clearly worsened before seeking a specialist opinion.

The orthopaedic vet assesses the whole hind limb, not just the mobility of the patella. This typically includes:

  • how often the patella luxates;
  • how it returns to place;
  • the alignment of the quadriceps and patellar tendon;
  • the shape of the femoral groove;
  • any possible bone deformity;
  • the stability of the cranial cruciate ligament.

This examination helps decide whether monitoring remains reasonable or whether surgery should be considered. Seeing a vet early enough also makes it possible to choose the moment when the surgical correction can still be as simple and as minimally invasive as possible.

You'll find a full overview of the surgical management on our dedicated patellar luxation page.

Acting before surgery becomes more involved

As the condition progresses, several procedures may become necessary. Surgery then becomes more complex, causes more inflammation, and can come with a longer recovery and a higher risk of complications.

The value of an early specialist opinion is being able to intervene, when indicated, before these additional procedures become necessary.

Tibial tuberosity transposition

In many cases, the main problem lies in the poor alignment of the patellar tendon.

This tendon attaches to a small bony bump at the front of the tibia: the tibial tuberosity (or tibial crest). If this tuberosity sits too far inward or outward, the pull of the quadriceps drags the patella out of its groove.

Tibial tuberosity transposition consists of moving this attachment point to bring the whole mechanism back into a more correct alignment.

During surgery, the surgeon partially detaches the tibial tuberosity, moves it in the required direction, then fixes it in its new position using small pins, sometimes combined with a wire.

The patellar tendon then pulls in line with the femoral groove. The patella is thus better guided as the dog bends and extends its knee.

This procedure is therefore not simply about holding the patella in place. It corrects part of the mechanical cause of the luxation.

Having the knee assessed at the right time

When the luxation is addressed early enough, and the femoral groove is still properly formed, a tibial tuberosity transposition alone may sometimes be sufficient. It can potentially be combined with a limited correction of the soft tissues around the patella.

As the condition progresses and the patella spends more and more time out of its normal position, the groove can become too shallow to guide it. A trochleoplasty may then need to be added: this procedure deepens the femoral groove to better contain the patella.

In more advanced cases, it may also be necessary to release contracted tissues, reinforce stretched tissues, or even correct a deformity of the femur or tibia.

A dog that regularly lifts a hind leg for a few steps should have an orthopaedic examination. This doesn't mean surgery will automatically be scheduled: the goal is to determine whether the luxation can still be monitored, or whether it is better to intervene before it worsens.

Early management often makes it possible to better preserve the normal structures of the knee, limit the number of procedures needed, and achieve the least invasive correction possible.

General information article. It does not replace a consultation: only a veterinary examination can establish a diagnosis and offer the treatment suited to your animal.

Does your dog sometimes lift a hind leg?

Have the patella assessed before it gets worse

No referral from another vet is needed: book an appointment directly for an orthopaedic examination or a second opinion.

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My dog is limping: what should I do?

Common causes and how an orthopaedic examination works.
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Cruciate ligament rupture

Another common cause of hind-limb limping.
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Patellar luxation: the surgery

Grades, diagnosis and the full surgical procedure at Colvet.