Reviewed by Dr Vishal Pai
Patella stabilisation surgery is a group of operations that stop the kneecap (patella) from dislocating. This page explains who might need surgery, which operation suits which cause of instability, and what recovery involves. Each operation has its own page with more detail.
At a Glance
- Surgery is the usual treatment if the kneecap keeps dislocating, or if a dislocation has damaged the cartilage. After a single dislocation, physiotherapy or early surgery may suit you, depending on your risk of it happening again.
- The operation is matched to the reason your kneecap is unstable, so it differs from person to person.
- An MPFL reconstruction is the most common operation. A tibial tubercle osteotomy is added for some people, and a trochleoplasty only when the groove is severely shallow.
What is patella stabilisation surgery?
An unstable kneecap can cause pain, and you may avoid normal activities because you worry it will dislocate. Stabilisation surgery corrects the cause of the instability, so the kneecap stays in its groove when you bend and twist the knee.
Three parts of the knee keep the kneecap in place:
- The medial patellofemoral ligament (MPFL) runs from the inner side of the kneecap to the thigh bone (femur). It stops the kneecap dislocating outwards, and it usually tears when the kneecap dislocates.
- The tibial tubercle (also called the tibial tuberosity) is the bony bump at the front of the shin bone where the kneecap tendon (patellar tendon) attaches.
- The trochlea is the groove at the end of the femur that the kneecap sits in. When it is shallow or dome-shaped, it is called trochlear dysplasia.
Each operation corrects a different problem, so they are not interchangeable, and some people need more than one at the same time. [1] Read more about the causes of an unstable kneecap on the patellofemoral instability page.
Who might need patella stabilisation surgery?
After a first dislocation, physiotherapy to strengthen the thigh and buttock muscles is one option, and physiotherapy is also part of recovery after surgery. [2] Read more about what to do after a kneecap dislocation.
About one in three people who dislocate their kneecap once will have it happen again. [3] Some features of your knee make another dislocation more likely: [3]
- A shallow or flat groove for the kneecap (trochlear dysplasia)
- A kneecap that sits higher than usual (patella alta)
- A kneecap tendon that attaches further to the outer side of the shin than usual. On a scan this is measured as the TT–TG distance, the gap between the tibial tubercle and the trochlear groove
- Being young, with growth plates that are still open
Loose joints (hypermobility) and differences in the rotation of the leg may also play a part, although the evidence for these is weaker. [4] [5] These features are checked on your X-rays and MRI scan, and they help decide which operation suits you.
Surgery is usually recommended if: [6]
- Your kneecap has dislocated more than once, because it is then likely to keep happening
- The first dislocation caused significant cartilage damage or left loose fragments in the knee
- You have several of the features above, which make another dislocation more likely [2]
In teenagers whose growth plates are still open, bone operations are usually delayed until growth has finished (see the FAQs below).
What is involved in patella stabilisation surgery?
Dr Vishal Pai plans which operations you need from your examination and scans. The table shows what each one corrects.
| Operation | Usually considered when | Early recovery |
|---|---|---|
| MPFL reconstructionMost commonReplaces the torn ligament on the inner side of the kneecap | The kneecap has dislocated more than once | Walking on the leg straight away, no brace |
| Tibial tubercle osteotomyMoves the point where the kneecap tendon attaches to the shin | The TT–TG distance is large or the kneecap sits high. Done with an MPFL reconstruction | Crutches, with a brace when walking, for 6 weeks |
| TrochleoplastyDeepens the groove the kneecap sits in | The groove is severely shallow or dome-shaped (severe trochlear dysplasia). Done with an MPFL reconstruction | A recovery plan made for you |
These operations are often done at the same time. When the TT–TG distance is large, a tibial tubercle osteotomy may be added to an MPFL reconstruction. The main steps are:
1. Knee arthroscopy
The operation is done under a general anaesthetic. A few small cuts let a camera and surgical tools into the knee joint. The whole joint is checked for damage, and to confirm that the kneecap sits out of its normal groove.
2. MPFL reconstruction
A hamstring tendon is used to make a new ligament. It is fixed to the edge of the kneecap with small anchors, and into a tunnel in the thigh bone (femur) with a screw, so the kneecap sits normally in its groove. Read more about MPFL reconstruction.
3. Tibial tubercle osteotomy (when needed)
The bony bump where the kneecap tendon attaches is cut free, moved to a better position and held with a plate and screws while the bone heals. Read more about tibial tubercle osteotomy.
4. Trochleoplasty (only for severe trochlear dysplasia)
The groove at the end of the femur is reshaped so the kneecap has a deeper channel to run in. It is combined with an MPFL reconstruction. [8] Read more about trochleoplasty.
How long does it take to recover from patella stabilisation surgery?
Recovery depends on which operations you have, and each operation’s page has its own timeline. The main differences are:
- MPFL reconstruction alone: you can put weight on your leg straight away and do not need a brace.
- With a tibial tubercle osteotomy: you use crutches and wear a straight-knee brace when walking for 6 weeks. An X-ray at 8 weeks checks that the bone is healing.
- With a trochleoplasty: Dr Vishal Pai will give you a recovery plan for that operation.
Whichever operation you have, physiotherapy starts after your first post-operative visit and focuses on your thigh muscles, straightening the knee and controlling swelling. Avoid resting with a pillow under your knee. Swelling can last 3 to 6 months. Most people with an office-based job return to work after 2 to 4 weeks, and people in physically demanding jobs after about 6 weeks. You can usually drive again at 6 weeks.
Dr Vishal Pai reviews you at about 6 months to check you’re ready to return to sport. The earliest return is at 6 months, once you have passed return-to-play testing, and it often takes longer after a tibial tubercle osteotomy. [9]
What results can you expect?
Patella stabilisation surgery stops the kneecap dislocating in most people. [7] Most people also return to sport after an MPFL reconstruction, many at the same level as before or higher. [10]
Further instability is uncommon after a tibial tubercle osteotomy. [11] After a trochleoplasty the kneecap rarely dislocates again, although a small number of people still feel it is not completely stable. [12]
These results come from published studies, not from one surgeon’s patients. People who need a bone operation often have more complex knees to begin with.
What are the risks and complications?
Dr Vishal Pai goes through the risks with you before you decide. The risks shared by all patella stabilisation operations are: [2]
- Pain at the front of the knee, which can relate to cartilage damage from earlier dislocations or the shape of the groove
- Stiffness, which occasionally needs a manipulation under anaesthetic if the knee is slow to bend or straighten in the first two months
- The kneecap dislocating again, which is uncommon and may need further surgery
- Infection, bleeding into the knee and blood clots in the leg, which are uncommon
Each operation also has risks of its own:
- MPFL reconstruction: rarely, the kneecap breaks, which may need an operation to fix. [13]
- Tibial tubercle osteotomy: the screws can be uncomfortable, and it is common to have them removed in a later operation. [14] Less often, the bone is slow to heal or breaks. [11]
- Trochleoplasty: stiffness is a particular risk. [12]
In teenagers there is a small risk of injury to a growth plate. Heart attack, stroke, a clot in the lungs (pulmonary embolism) and death are rare. You will receive a written information sheet with the full list of risks.
Where does Dr Vishal Pai consult and operate?
Dr Vishal Pai consults at Sandringham Orthopaedic Specialists, Suite 1, 60 Bay Road, Sandringham. He performs patella stabilisation surgery at Calvary Holmesglen Private Hospital, 490 South Road, Moorabbin, and The Avenue Hospital, 40 The Avenue, Windsor. Patients come from across Bayside, Glen Eira and the Mornington Peninsula, and some travel from regional Victoria.
References
Show all 15 referencesHide references
- Phillips AR et al. 2024. Isolated medial patellofemoral ligament reconstruction results in lower failure and complication rates than isolated trochleoplasty and tibial tubercle osteotomy: a systematic review. Arthroscopy.
- Balcarek P et al. 2025. Management of first-time patellar dislocation: the ESSKA 2024 formal consensus, part 2. Knee Surgery, Sports Traumatology, Arthroscopy.
- Huntington LS et al. 2019. Factors associated with an increased risk of recurrence after a first-time patellar dislocation: a systematic review and meta-analysis. The American Journal of Sports Medicine.
- Heighes LA et al. 2024. The relationship between joint hypermobility and patellar instability: a systematic review. Journal of Orthopaedics.
- Only A et al. 2024. Anatomic risk factors for lateral patellar instability. Arthroscopy.
- Liu JN et al. 2018. Patellar instability management: a survey of the International Patellofemoral Study Group. The American Journal of Sports Medicine.
- Vivekanantha P et al. 2022. Isolated medial patellofemoral ligament reconstruction results in similar postoperative outcomes as medial patellofemoral ligament reconstruction and tibial-tubercle osteotomy: a systematic review and meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy.
- Dejour D et al. 2021. Trochleoplasty: indications in patellar dislocation with high-grade dysplasia. Surgical technique. Orthopaedics & Traumatology: Surgery & Research.
- Li ZI et al. 2024. Patients who undergo tibial tubercle anteromedialization with medial patellofemoral ligament reconstruction demonstrate similar rates of return to sport compared to isolated MPFL reconstruction. Knee Surgery, Sports Traumatology, Arthroscopy.
- Platt BN et al. 2021. Return to sport after medial patellofemoral ligament reconstruction: a systematic review and meta-analysis. The American Journal of Sports Medicine.
- DeNovio AC et al. 2025. Incidence of complications, recurrent instability, and all-cause reoperations after tibial tubercle osteotomy for patellofemoral instability: a systematic review and meta-analysis of the literature. Orthopaedic Journal of Sports Medicine.
- Leclerc JT et al. 2021. Complications and outcomes of trochleoplasty for patellofemoral instability: a systematic review and meta-analysis of 1000 trochleoplasties. Orthopaedics & Traumatology: Surgery & Research.
- Abelleyra Lastoria DA et al. 2026. The incidence and epidemiology of patellar fractures following medial patellofemoral ligament reconstruction: a systematic review and meta-analysis. Archives of Orthopaedic and Trauma Surgery.
- Payne J et al. 2015. The incidence of complications of tibial tubercle osteotomy: a systematic review. Arthroscopy.
- Sanders TL et al. 2017. Patellofemoral arthritis after lateral patellar dislocation: a matched population-based analysis. The American Journal of Sports Medicine.
Frequently asked questions
Will I need a brace after surgery?
Not after an MPFL reconstruction on its own. If a tibial tubercle osteotomy is done at the same time, you will use crutches and wear a straight-knee brace when walking for 6 weeks.
Will patella stabilisation surgery affect my teenager's growth plates?
Kneecap dislocations usually happen in growing teenagers, whose growth plates around the knee are still active. Bone operations such as a tibial tubercle osteotomy or a trochleoplasty can damage a growth plate, so it is recommended to wait until growth has stopped. The right combination of surgery can then be done. If treatment without surgery isn’t working, an MPFL reconstruction can be done to help with the instability. There is still a small risk of injury to the growth plate in the femur, which Dr Vishal Pai will discuss with you and your family.
Is patellofemoral instability associated with developing knee arthritis?
Yes. Dislocating the kneecap raises the chance of arthritis behind the kneecap later in life, especially if dislocations keep happening or the cartilage was damaged. [15] Stabilisation surgery prevents further dislocations in most people, but long-term studies have not yet shown whether it also lowers the risk of arthritis.
When can I drive after patella stabilisation surgery?
You will not be able to drive for 6 weeks after a tibial tubercle osteotomy, an MPFL reconstruction, or both. You must be off strong painkillers, be walking without crutches, and have a relatively pain-free range of motion in the knee before you start driving.
When can I swim after patella stabilisation surgery?
Keep the wound dry for 2 weeks after the operation. Once the wound has been checked at your 2-week appointment, you can shower without a dressing. Avoid swimming and pool-based rehabilitation for 3 weeks after your operation, because it may increase the risk of infection.
Next step
Talk through your options
If you are weighing up patella stabilisation surgery, Dr Vishal Pai can examine your knee, review your scans and explain all your options, including treatment without surgery.