Introduction
Knee care · Knee arthritis
Knee osteotomy surgery (high tibial and distal femoral osteotomy): what it is, when it is considered and what recovery involves
Dr Sean Leo · Orthopaedic Surgeon (Specialist in Orthopaedic Surgery) · Clinical Interest: Knee Conditions, Injuries & SurgeryMBBS, MRCS (Ed), MMed (Ortho), FRCSEd (Ortho)
Last updated: 15 October 2026.
Dr Sean LeoOrthopaedic Surgeon, Singapore
Clinic enquiries · Not an emergency service
Illustrative image
Knee osteotomy in brief
Knee osteotomy in brief
Knee osteotomy in brief
Knee osteotomy realigns the leg to move weight off the worn side of an arthritic knee. It is considered for selected people who have arthritis on one side of the knee and a leg-alignment problem. It can delay the need for a knee replacement. Recovery takes patience, because the bone has to heal.
The operation shifts load. It does not reverse cartilage wear that is already there.
What’s covered on this webpage
Follow the route in order, or jump to the stop you need. Stops you have read are marked.
How the leg’s alignment carries weight through the knee
How the leg’s alignment carries weight through the knee
How the leg’s alignment carries weight through the knee
A knee has three compartments: the inner (medial) side, the outer (lateral) side, and the front, where the kneecap meets the thigh bone.
In a typical leg standing on one leg, about three-quarters of the load across the knee goes through the inner side [9]. That is typical biomechanics, not a measurement of your knee.
The line your weight takes from hip to knee to ankle sets the balance. Surgeons call it the mechanical axis: the straight line from the centre of the hip to the centre of the ankle. Where it crosses the knee shows which side carries more.
In a bow-legged (varus) leg, the inner side takes more load [9]. In a knock-kneed (valgus) leg, the outer side does [8][9].
How one-sided wear happens
How one-sided wear happens
How one-sided wear happens
Cartilage wears faster where load concentrates. When arthritis is confined to one compartment and the leg is out of line, the worn side is often the side taking the most weight.
Correcting the alignment moves load away from that side [1][9]. It redistributes weight. It does not cure the arthritis.
You may know the problem as bow legs (varus) or knock knees (valgus). In adults, these alignments can matter when one side of the knee is arthritic. This page covers that adult situation, not knock knees in childhood.
Alignment is one contributor among several. Bow legs or knock knees do not by themselves mean you need an operation.
What does one-sided knee arthritis feel like
What does one-sided knee arthritis feel like
What does one-sided knee arthritis feel like?
It varies from person to person. Pain and stiffness usually sit on the worn side and build with activity. The knee may swell afterwards, and longer walks or sport can get harder.
Some people notice that the leg looks bowed or knock-kneed in the mirror or in photographs. That is a fair reason to ask for an assessment. It is not an emergency.
Which osteotomy, and one that is not
Which osteotomy, and one that is not
Which osteotomy, and one that is not
An osteotomy is a controlled cut in a bone. Two osteotomies realign an arthritic knee. A third has a similar name and treats a different problem.
High tibial osteotomy (HTO)
The surgeon cuts the upper shin bone (the tibia). The cut moves the line of weight outward in a bow-legged (varus) knee, away from the worn inner side [1][9].
Distal femoral osteotomy (DFO)
The same principle, applied at the lower thigh bone (the femur). It is used for a knock-kneed (valgus) knee with a worn outer side, and it moves the line of weight inward [1][8][9]. The evidence base is smaller than for HTO, so DFO figures later on this page are ranges [8].
A different operation: tibial tubercle osteotomy (TTO)
Tibial tubercle osteotomy is kneecap realignment. It treats a kneecap that slips out of its groove. It works on a different bone, the bump on the shin where the kneecap tendon attaches. Nothing on this page applies to it. See Kneecap realignment surgery.
More on opening wedge and closing wedge
In an opening-wedge osteotomy, the surgeon opens a gap in the bone and fills it with graft or a bone substitute. In a closing-wedge osteotomy, a small wedge of bone is removed and the gap is closed. The choice depends on the planning for your leg and belongs to the surgeon.
When to seek assessment
When to seek assessment
When to seek assessment
An assessment is worth arranging if one-sided knee pain persists or limits what you do despite reasonable non-surgical measures, if your leg looks bow-legged or knock-kneed as an adult, or if you want to know whether alignment is part of the picture. Asking does not mean you have decided on surgery. Urgent symptoms are listed under Final next step.
How knee osteotomy is assessed
How knee osteotomy is assessed
How knee osteotomy is assessed
Assessment starts with your story: where the knee hurts, for how long, and what it limits. Then the surgeon examines how your leg lines up when you stand, how you walk, and the knee itself.
Imaging usually includes standing full-leg X-rays, taken from hip to ankle while you stand. They let the surgeon measure the mechanical axis and see whether the arthritis is confined to one compartment. An MRI scan is added only when there is a specific extra question.
An X-ray shows alignment and arthritis. It does not show how much the knee bothers you. Your symptoms and your images are weighed together, and no single measurement decides.
What can be tried before surgery
What can be tried before surgery
What can be tried before surgery
Non-surgical care is a genuine part of the plan. It includes adjusting activities that aggravate the knee, weight management where relevant (osteoarthritis and weight loss), targeted physiotherapy, a discussion of injection options, and offloader bracing (knee braces for arthritis).
For a younger, active person with malalignment and wear on one side, these measures can ease symptoms. They do not change the alignment of the leg.
When knee osteotomy is considered
When knee osteotomy is considered
When knee osteotomy is considered
The classic picture is arthritis confined to one compartment, an alignment that loads that side, and an active person for whom keeping their own joint matters. That person is often, but not always, younger [1][3].
In one study of 100 people who had an HTO, the best candidates were under 55, not obese, and had not progressed to severe symptomatic disability [3]. These are selection factors from one group, not cut-offs.
Arthritis that is not confined to one side of the knee is weighed carefully in the assessment, because the operation is built around a single worn compartment [1].
Osteotomy for more advanced arthritis, including bone-on-bone wear, is a developing area. A 2024 systematic review found good mid- and long-term survival and satisfactory patient-reported results in young to middle-aged people, but most of its studies were low-level evidence [7]. It is a question for selected cases, not a standard approach for end-stage arthritis.
Structure / Patient / Goal
Structure / Patient / Goal
Deciding together
Structure / Patient / Goal
The decision rests on three questions: structure, patient and goal. A scan can answer only the first.
S
Structure: what the knee and the leg look like
Which compartment is worn, whether the arthritis is confined to it, and how far the leg is out of line.
P
Patient: who you are and what you can carry
Age, activity level and weight play a part [3], as selection factors and not cut-offs. So do your general health, work, family and tolerance for recovery time and risk.
G
Goal: what you want to get back to
Walking without worry, recreational sport or something more demanding each changes what a useful result looks like. Keeping your own joint is one goal; another goal may point to a different operation.
Your plan
Together, Structure / Patient / Goal weighs the question without treating any single factor, or any one scan, as decisive.
Osteotomy versus partial and total knee replacement
Osteotomy versus partial and total knee replacement
Osteotomy versus partial and total knee replacement
Preserve the joint, or replace it? This is a decision about you, not a score between two operations. The evidence points in two directions, and both findings are here.
One finding favours partial replacement. A meta-analysis pooled 39 studies and 56,686 patients. People who had a partial knee replacement had fewer complications, fewer later conversions to total knee replacement and lower pain scores than people who had HTO. The authors concluded that partial replacement did better on those measures [5].
These were not randomised comparisons. People having HTO tend to be younger and more active, so the groups were not alike from the start [5].
Another finding supports osteotomy for a particular group. HTO keeps a distinct role for younger, active people with a bow-legged knee. A review reported that, in young patients, osteotomy followed by a later total knee replacement did better for knee survival than an early total knee replacement. That finding is cited from earlier work and is indirect [7].
The two findings describe different groups of people. Neither tells you which operation suits your knee. Structure, Patient and Goal, above, are how that is decided.
The table sets the four operations side by side. It describes. It does not rank. Read more on the partial knee replacement and total knee replacement pages.
| HTO | DFO | Partial knee replacement | Total knee replacement | |
|---|---|---|---|---|
| What it is | Realigns the leg at the upper shin bone | Realigns the leg at the lower thigh bone | Replaces one worn compartment with an implant | Resurfaces worn joint surfaces across the whole knee |
| What is done | A controlled cut in the bone, held with a plate and screws while it heals | The same, at the thigh bone | Only the worn compartment is resurfaced; the rest of the knee, including the ligaments, is kept | The worn surfaces of the whole joint are resurfaced |
| Who it typically suits | Selected, often younger, active people with a bow-legged knee and a worn inner side | Selected people with a knock-kneed knee and a worn outer side | Arthritis confined to one compartment, with intact ligaments | Wear spread across the knee |
| Recovery and durability | Bone must heal, so weight-bearing is protected at first; figures are below | Same principle; thinner evidence, so ranges | Described on its own page | Registry figures are on its own page |
A later replacement stays possible. A previous high tibial osteotomy no longer rules a partial replacement out on its own, though it is still weighed in the assessment.
What happens during knee osteotomy surgery
What happens during knee osteotomy surgery
The operation
What happens during knee osteotomy surgery
The correction is planned beforehand on standing full-leg X-rays.
The surgeon makes a controlled cut in the bone, either opening a gap that is filled with graft or bone substitute, or removing a small wedge. The leg is moved to the planned new angle and the bone is held with a plate and screws while it heals.
The aim is a planned correction to a new angle, sized to your leg. It changes where the load goes, not the arthritis itself.
Recovery
Recovery
Recovery
Recovery: what to expect at each stage
Recovery is judged on criteria, not on a date. These ranges are typical, and your surgeon’s protocol sets your pace [1]. General principles are in post-surgery recovery.
- In hospital. A stay of about one to two days is typical [1].
- The first six weeks or so. Weight-bearing is protected and you use crutches while the bone heals [1].
- Building up. Loading increases as X-rays show the bone healing. Return to full activities typically falls between three and six months [1].
More on work, sport and activity levels
Work: in pooled results from 8 studies of proximal tibial osteotomy, 80.8% returned to work, on average at about three and a half months (105 days). Reasons for surgery and types of job were mixed [2].
Sport: in pooled results from 24 studies, 75.7% returned to sport. Definitions varied, and the level was often lower than before. It is not a promise [2].
Activity: in a pooled review, people who had HTO or a partial knee replacement both returned to the same or a greater level of activity than before surgery. It was not a head-to-head trial [6].
Your surgeon will tell you when it is safe to drive. There is no single date that suits everyone.
Full stage-by-stage detail is in Knee osteotomy recovery.
Risks and complications
Risks and complications
Risks and complications
Osteotomy is bone surgery, with a real list of possible complications.
In a systematic review of proximal tibial osteotomy, the overall complication rate was about 11%. The most common were hardware failure (about 2.5%) and infection (about 2.1%) [2]. These are pooled figures from several kinds of tibial osteotomy, with different reasons for surgery and some older series. Treat them as a ballpark, not as your personal risk.
The recognised risks are:
- infection;
- blood clots;
- knee stiffness;
- failure of the bone to heal (nonunion);
- nerve or blood-vessel injury;
- irritation from the plate or screws, sometimes needing later removal [1].
Some people need a knee replacement later. This is an expected pathway for a minority, not a failure of care [2].
The urgent-signs list under Final next step says what needs prompt help, including after knee surgery. Your surgeon will go through the risks that apply to you.
How long does an osteotomy last?
How long does an osteotomy last?
How long does an osteotomy last?
For well-selected people, most osteotomies are still working at ten years. The picture is time bought, not a cure.
In these studies, an osteotomy “survives” if the knee has not needed a replacement or revision. Survival does not mean pain-free. People can keep an osteotomy and still have pain [4].
The figures below use different techniques and different follow-up, so they should not be blended.
- Medial opening-wedge HTO, ten years or more. In a pooled analysis, 86% had not needed a knee replacement (95% confidence interval 80% to 90%). Asian studies pooled to 92%, European studies to 84% [4].
- Closing-wedge HTO, twenty years. In an older series of 100 people, 44% overall still had their osteotomy at twenty years. Among favourable candidates (younger, lower body weight, better function before surgery), the figure was 62% [3].
- Proximal tibial osteotomy, about six years. In one review, 12.5% had converted to a total knee replacement by an average of about six years [2].
- Distal femoral osteotomy. Reported survival ranged from 74% to 88% at five years, 74% to 90% at ten years, and 45% to 79% at fifteen years [8].
Osteotomy delays the need for a replacement. It does not take its place [7]. A total knee replacement has its own durability evidence, on the total knee replacement page, and the two sets of figures should not be compared directly. These figures describe groups of patients, not you.
When osteotomy is combined with other procedures
When osteotomy is combined with other procedures
When osteotomy is combined with other procedures
Osteotomy can be done on its own. Where cartilage repair is being considered, the alignment of the leg is part of the assessment. The cartilage repair page explains how.
If the arthritis moves on, a knee replacement later remains possible [2][7].
OrthoKinetics Recovery Reflection
Recovery reflection
What changes when your leg carries you along a new line?
After a realignment, the knee is still your knee. What has changed is the route your weight takes through it. Part of recovery is learning to trust that route. Once the leg is cleared to take weight again, every ordinary step is a quiet rehearsal of the new line. Confidence can arrive a little behind what the bone has already done.
Illustrative image
With you through the seasonsMeet Dr Sean Leo
Meet Dr Sean Leo
A consultant orthopaedic surgeon whose clinical focus is the knee, sports injuries and the lower limb.
- Dr Sean Leo is a consultant orthopaedic surgeon. OrthoKinetics is his professional brand; clinical services are provided through OrthoSports Orthopaedic & Sports Surgery at Mount Elizabeth Novena Specialist Centre and Connexion, Farrer Park Hospital.
- His clinical interests include sports injuries, including those in adolescent athletes; ligament reconstruction; realignment surgery; cartilage repair and joint-preservation approaches; knee replacement; and technology-assisted hip and knee surgery.
- The consistent aim is to return people to meaningful function and activity while avoiding unnecessary downtime.
- Qualifications: MBBS, MRCS (Ed), MMed (Ortho), FRCSEd (Ortho).
More detail: Meet Dr Sean Leo
- Training and career: Dr Leo trained in medicine at the National University of Singapore and served in the Singapore Armed Forces Medical Corps from 2000 to 2012, where his work included the care of soldiers in physically demanding roles. He completed postgraduate orthopaedic training in 2009 and a one-year clinical fellowship at Royal North Shore Hospital in Sydney, Australia, before joining Changi General Hospital as an orthopaedic consultant in 2012, where he later held the positions of Senior Consultant and Director of the Hip and Knee Service. With seniority, his educational contribution has evolved towards mentorship and support for junior doctors.
Questions people often ask
Common knee osteotomy questions
Common knee osteotomy questions
What is knee osteotomy, and how does it differ from knee replacement?
Osteotomy realigns a bone so that weight moves off the worn side of the knee, and keeps your own joint. A replacement resurfaces worn surfaces with an implant [1][9].
Is knee osteotomy the same as kneecap realignment surgery?
No. Kneecap realignment, a tibial tubercle osteotomy, treats a kneecap that slips out of its groove, on a different bone. See Kneecap realignment surgery.
Can osteotomy delay or avoid knee replacement?
It can delay it [7]. It cannot promise to avoid it, and some people need a replacement later [2][3][4]. The figures are under How long does an osteotomy last?
Am I too old or too young for knee osteotomy?
Age is one factor among several. In one group of patients, the best candidates were under 55, but that was a selection factor and not a cut-off [3]. The assessment weighs everything together.
When can I walk without crutches, drive, work and return to sport?
Typically, weight-bearing is protected, with crutches, for roughly six weeks, and your surgeon increases loading as X-rays show healing [1]. Your surgeon decides when driving is safe, and there is no single date for everyone. In pooled results, about four in five people returned to work, on average at about three and a half months, and about three in four returned to sport, often at a lower level [2]. These are averages, not promises.
What are the risks, and how common are they?
In pooled data, about 11% of people had a complication [2]. The full list is under Risks and complications.
Can I have a knee replacement later if the arthritis progresses?
Yes, a knee replacement later remains possible [2][7]. A previous high tibial osteotomy no longer rules a partial replacement out on its own, though it is still weighed in the assessment.
What do people mean by a “knee specialist”?
“Knee specialist” is an everyday phrase many people use when looking for a doctor for a knee problem. In Singapore, doctors may only use the specialist titles accredited by the Specialist Accreditation Board (SAB) of the Ministry of Health (MOH). Orthopaedic Surgery is an accredited specialty; the knee is an area of clinical interest within it. “Knee specialist” is not a separate specialist registration; however, individual orthopaedic surgeons may have particular clinical interests within their specialty. The doctor most people have in mind is an orthopaedic surgeon whose practice focuses on knee conditions. Dr Sean Leo is registered as a specialist in Orthopaedic Surgery, and his clinical interest is the knee. He completed a postgraduate knee fellowship programme in Sydney, Australia, at the Royal North Shore Hospital under Dr Myles Coolican and Dr David Parker from 2009 to 2010. Dr Leo was also Director of the Hip and Knee Service at Changi General Hospital from 2014 to 2018.
Costs and insurance
Costs and insurance
Practicalities
Cost, MediSave and insurance
A cost estimate for surgery can be given only after a consultation and assessment, once a surgical plan has been developed. A surgical estimate separates surgeon, anaesthetist, hospital or facility, implant and consumable costs, and the MOH publishes national fee benchmarks for common procedures.
MediSave, MediShield Life and Integrated Shield Plans are the scheme routes through which a knee osteotomy may be partly funded in Singapore. Eligibility, claim limits and the amount actually covered depend on your personal circumstances and policy terms, so this page cannot advise on what any individual will pay or recover.
For how costs, MediSave and insurance work in Singapore, see Costs, insurance and MediSave, explained.
Insurance panels. Dr Sean Leo, Orthopaedic Surgeon, is on the specialist panels of Great Eastern (GE Panel), HSBC Life (HSBC Life Shield) and Singlife (Singlife Shield), and on the Prudential Panel. AXA Insurance Singapore became part of HSBC Life in 2023, and former AXA Shield plans are now HSBC Life Shield plans.
Corporate health plans. Dr Leo is on the panels of both Alliance Medinet and iXchange, which administer medical benefits for many company health plans. If your company plan uses either panel, you can see Dr Leo as a panel doctor.
If your company uses a different panel. Some company plans still let you see a doctor of your choice outside their panel, then claim reimbursement. This varies from plan to plan, as may the co-payment, so please check your benefits with your company’s HR department.
Panel arrangements change from time to time, so please confirm with your insurer or your company’s plan administrator before your appointment.
Dr Leo is on the panels shown. If your insurer is not listed, you may ask whether co-management with an Orthosports surgeon partner on that panel is clinically and administratively appropriate. Orthosports surgeon partners are collectively on the panels of all Shield plans.
Benefits, pre-authorisation, letters of guarantee, panel rules and reimbursement depend on your individual policy and the insurer’s decision. Neither panel status nor co-management guarantees coverage, approval or cashless treatment.
The clinic team can assist with claim paperwork, including personal accident, hospitalisation or travel claims from other insurers, but cannot promise the outcome.
To discuss your own situation, you can arrange an assessment.
Arrange a consultation: the appointment section is further down this page.
Sources
References
References
- American Academy of Orthopaedic Surgeons. Osteotomy of the Knee. OrthoInfo (patient education). https://orthoinfo.aaos.org/en/treatment/osteotomy-of-the-knee/
- Kunze KN, et al. Return to Work and Sport After Proximal Tibial Osteotomy and the Effects of Opening Versus Closing Wedge Techniques on Adverse Outcomes: A Systematic Review and Meta-analysis. Am J Sports Med. 2020;48(9):2295-2304. doi:10.1177/0363546519881638. PMID:31774691.
- Constantin M, et al. 20-Year Outcomes of High Tibial Osteotomy: Determinants of Survival and Functional Outcome. Am J Sports Med. 2024;52(2):344-351. doi:10.1177/03635465231217742. PMID:38243788.
- Ge Y, Häner M, Borges JS, Stöckle U, Petersen W. Long-term survivorship after medial open-wedge high tibial osteotomy: a systematic review and single-arm meta-analysis with regional subgroup analysis. Knee Surg Sports Traumatol Arthrosc. 2026;34(4):1390-1404. doi:10.1002/ksa.70326. PMID:41696927.
- Waseem MH, et al. Comparison of Unicompartmental Knee Arthroplasty Versus High Tibial Osteotomy for Medial Knee Osteoarthritis: An Updated Meta-Analysis of 56,000 Patients. Orthop Surg. 2025. doi:10.1111/os.70049. PMID:40694375. PMCID:PMC12404872.
- Belsey J, Yasen SK, Jobson S, Faulkner J, Wilson AJ. Return to Physical Activity After High Tibial Osteotomy or Unicompartmental Knee Arthroplasty: A Systematic Review and Pooling Data Analysis. Am J Sports Med. 2021;49(5):1372-1380. doi:10.1177/0363546520948861. PMID:32960075. PMCID:PMC8020302.
- Dal Fabbro G, Grassi A, Agostinone P, Lucidi GA, Fajury R, Ravindra A, Zaffagnini S. High survivorship rate and good clinical outcomes after high tibial osteotomy in patients with radiological advanced medial knee osteoarthritis: a systematic review. Arch Orthop Trauma Surg. 2024;144(9):3977-3988. doi:10.1007/s00402-024-05254-0. PMID:38430233. PMCID:PMC11564305.
- Yazdi H, Torkaman A, Sahrai R, Raygani MJ, Makhmalbaf AR, Fathi M. Distal Femoral Varus Osteotomy in Valgus Knee With Lateral Compartment Osteoarthritis: A Systematic Review. J Am Acad Orthop Surg Glob Res Rev. 2025;9(10). doi:10.5435/JAAOSGlobal-D-25-00121. PMID:41082590. PMCID:PMC12513449.
- Liu X, Chen Z, Gao Y, Zhang J, Jin ZM. High Tibial Osteotomy: Review of Techniques and Biomechanics. J Healthc Eng. 2019. PMCID:PMC6525872.
Final next step
Final next step
Next step
Final next step
Reading about a problem is a starting point. An assessment brings together the history, an examination where needed and any useful tests, and helps you and your clinician decide what to do next.
Signs that need urgent help
Some symptoms should not wait for a routine appointment. Each item below says where to go.
After an injury
- The kneecap has slipped out of place and is still out, or the knee looks deformed. Go to an emergency department. If the kneecap went back into place by itself, arrange an early assessment.
- The leg looks twisted or bent, a bone is showing, there is a deep cut, or the foot or leg turns cold, pale, numb, blue or white. Go to an emergency department or call 995.
- You cannot lift your leg up with the knee kept straight, and you may feel a gap just above or just below the kneecap. Arrange an urgent same-day assessment.
At any time
- The knee is stuck and will not straighten, or it is very painful and you cannot move it or put weight on it. Arrange an urgent same-day assessment.
- The knee is suddenly very painful, hot, red and swollen, especially with a fever or feeling generally unwell. Go to an emergency department or call 995.
- One calf or thigh is newly painful and swollen. Arrange an urgent same-day assessment. If you also feel short of breath or have chest pain, call 995.
After knee surgery
- The operated knee becomes more painful, swollen or red, a wound is leaking, or you develop a fever. Contact your surgical team straight away. If you cannot reach them the same day, go to an emergency department. If you feel very unwell, go to an emergency department. If you are short of breath or have chest pain, call 995.
If you are admitted by the doctor at the urgent care centre of one of these private hospitals, the Parkway Pantai hospitals (Mount Elizabeth Orchard, Mount Elizabeth Novena, Gleneagles and Parkway East), Farrer Park Hospital and Thomson Medical Centre, you may ask for Dr Sean Leo to be your attending orthopaedic surgeon. If you are instead discharged and referred for orthopaedic follow-up, you may contact the clinic to arrange an appointment. Both are subject to the hospital’s admission processes and to Dr Leo’s availability.
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