Osteotomy literally means "cutting of the
bone." In high knee osteotomy, the tibia (shinbone) is cut and
then reshaped to relieve pressure on the medial compartment of
knee joint. It is used when you have early-stage osteoarthritis
that has damaged just one side of the knee joint. By shifting
your weight off of the damaged side of the joint, an osteotomy
can relieve pain and significantly improve function in your arthritic
Why does arthritis affect one side of the
Medial osteoarthritis can develop when the bones of your knee
joint do not line up properly. This is a common situation in Asian
sub-continent, as people of this region genetically have varus
knee alignment. This can put extra stress on the inner (medial)
side of your knee. Over time, this extra pressure can wear away
the smooth cartilage that protects the bones, causing pain and
stiffness in your knee. A trivial incidence of trauma to the knee
joint can aggravate the process of medial joint wear out.
Goals of High Tibial Osteotomy
To transfer weight from the arthritic medial compartment of the knee to a healthier lateral compartment by correcting the alignment of knee joint, thus prolonging the life span of the knee joint.
Advantages and disadvantages of HTO
By preserving your own knee anatomy, a successful osteotomy may delay the need for a joint replacement for several years. Another advantage is that there are no restrictions on physical activities after an osteotomy - you will be able to comfortably participate in your favorite activities, even high impact exercise.
Though big claims are made regarding survival of arthroplasty implant, with catchy statements like "joints for life time" being common in media, high impact activities can result in early failure of arthroplasties.
Osteotomy does have disadvantages. For example, pain relief is not as predictable after osteotomy compared with a partial or total knee replacement.
Because you cannot put your weight on your leg after osteotomy, it takes longer to recover from an osteotomy procedure than a partial knee replacement.
In some cases, having had an osteotomy can make later knee replacement surgery more challenging.
Results from total knee replacement and partial knee replacement have been excellent, making knee osteotomy a less preferred procedure. Nevertheless, it remains an option for many patients, since the procedure is very economical as compared to arthroplasty.
High tibial osteotomy can be performed by open wedge or close wedge technique. Both techniques have their own pros & cons. We prefer open wedge technique with locking plate or Ex-fix construct. Ex-fix HTO clamp being my personal favorite, since it allows more precise control over the final alignment. During this procedure two pins are fixed in upper part of shin bone and two pins are fixed in lower part of shin bone and oblique osteotomy is performed with hing at proximal tibiofibular joint (outer side of proximal shin bone). Distractor is attached to the pins fixed on shin bone, which is gradually distracted over next few days. This results in medial opening of the osteotomy, and shifts the weight-bearing axis from medial compartment to lateral compartment of knee. As the load is transferred to lateral (healthy) compartment of knee and medial compartment is distressed, this resulting in pain relief. Scientific studies have documented growth of healthy cartilage one eroded medial compartment of the knee joint.
Candidates for Knee Osteotomy
Knee osteotomy is most effective for thin, active patients who are 40 to 60 years old, though we have successfully used it in younger patients who had post-traumatic and post-operative varus knee deformities.
Good candidates have pain on only one side of the knee, and no pain under the kneecap. Knee pain should be brought on mostly by activity, as well as standing for a long period of time.
Candidates should be able to fully straighten the knee and bend it at least 90 degrees.
You will likely be admitted to the hospital on the day of surgery.
Before your procedure, a doctor from the anesthesia department will evaluate you. He or she will review your medical history and discuss anesthesia choices with you. We prefer regional anesthesia (spinal), so that you are awake but your body is numb from the waist down.
Your surgeon will also see you before surgery and mark your knee to verify the surgical site.
A knee osteotomy operation typically lasts between 60 to 90 minutes. As a protocol, we routinely perform arthroscopic debridement and micro-fracture in the same sitting, unless there is a reason for not doing the same. Arthroscopic debridement is a pen hole surgery in which the knee joint is thoroughly examined from inside to look for amount and kind of damage to the knee joint along with removing any debris generated by the arthritic process. Additional issues like meniscus tears are addressed and microfractures are performed stimulate cartilage formation in eroded medial femoral condyle.
Following this, your surgeon will make stab incisions on medial side of your upper shin bone to fix to pins. HTO clamp in applied and to pins are fixed in lower part of shin bone at distal holes of clamp.
He will plan the correct site of the wedge using guide wires under fluoroscopy control. With an oscillating saw, your surgeon will cut along the guide wires to create an osteotomy. HTO clamp is fixed in compression mode and osteotomy wound in closed after confirming completeness of osteotomy by distracting it once under fluoroscopy control.
In some cases, the wedge of bone is "opened" and a bone graft is added to fill the space and help the osteotomy heal. In this situation the osteotomy is fixed with locking plate after correcting the alignment under fluoroscopy control.
After the surgery, you will be taken to the recovery room where you will be closely monitored as you recover from the anesthesia. Following this you will then be taken to your hospital room.
In most cases, patients stay at the hospital for 1 to 2 days after an osteotomy. During this time, you will be monitored and given pain medication. Your surgeon will explain you exercises to strength thigh muscles, maintain knee ROM
You will most likely need to use crutches for several weeks. On 10th post-operative day, you will be explained distraction technique. Distraction is carried out on daily bases for 3 – 4 weeks depending upon amount of deformity to be corrected. X-rays will be taken at regular intervals so that your surgeon can check how well the osteotomy is distracting. When required distraction (as calculated pre-operatively) is achieved, knee alignment is checked under fluoroscopy control to confirm adequate correction of deformity. Once the target is achieved, HTO distraction device is locked and full weight bearing is allowed. You can walk with the help of aids for next 4 weeks, when distractor is removed.
During rehabilitation, a physical therapist will give you exercises to help maintain your range of motion and restore your strength.
You may be able to resume your full activities after 3 to 6 months.
As with any surgical procedure, there are risks involved with osteotomy. Your surgeon will discuss each of the risks with you and will take specific measures to help avoid potential complications.
Although the risks are low, the most common complications include:
- Blood clots
- Stiffness of the knee joint
- Injuries to vessels and nerves
- Failure of the osteotomy to heal
Very rarely, a second surgery may be required, particularly if the osteotomy does not heal.
Osteotomy can relieve pain and delay the progression of arthritis in the knee. It can allow a younger patient to lead a more active lifestyle for many years. Even though many patients will ultimately require a total knee replacement, an osteotomy can be an effective way to buy time until a replacement is required.
Commonly asked questions?
Are there limitations on activity after an HTO?
Limitations after HTO are minimal among all the treatment options for osteoarthritis knee i.e. Unicondylar knee replacement, Total knee replacement and High tibial Osteotomy. Limitations after joint replacement are important since the bone cement interface can fail under extremes of stress like running and jumping. In HTO its natural knee joint whose alignment has been corrected to off load the over loaded medial compartment. Since there is no artificial component in the knee, you can treat your knee as original or unaffected knee.
Will my knee be as good as normal knee?
Since HTO is usually done for OA it is not possible to expect a completely normal knee when surgery and recovery are complete. However, it is possible to return to whatever activities can be tolerated within the limits of one’s own residual level of pain and discomfort.
In general the HTO should severely slow down future further development of degenerative osteoarthritic change and allow improved but probably not completely pain free function post-op.
If the OA is moderately severe at the time of the HTO, most people will be able to delay the possible future knee replacement by almost a decade.
Will I have a lot of pain after surgery?
Perception of pain varies from person to person. It is present on first post-operative day; however, by 2nd post-operative day it reduces to tolerable levels, which will not require injectable analgesics. You will have minimal pain by the time you are discharged.
How long will I be in hospital after the surgery?
We generally discharge all our patients next day afternoon. Diabetic patients with not so good control of blood sugar levels might have to extend hospitalization by one day. Similarly pain management requiring injectable analgesics can be another reason for delay in discharge.
How long does it take to achieve full correction of alignment?
Your surgeon will provide you estimate time after surgery. We routinely start distraction 10 days after surgery and distract osteotomy @ 1 mm per day. Majority of patients require 20 to 25 mm of distraction depending upon degree of varus. With this calculation distraction ends at 30 to 40 days after surgery. This figure can vary from person to person.
What do I do to care for the surgical wound and pin tracts?
First dressing change is done on first post-operative day, before discharging the patient. Second dressing is changed at week’s interval. If any stitches are applied at osteotomy site, they are moved on 12th post-op day. Osteotomy wound is left open 14 days after surgery. Pin tracts need regular care till the fixator is removed. All that one needs to do is to clean the pin tracts with hospital spirit twice days and apply betadine ointment over it.
Is swelling of knee joint a normal phenomenon?
Knee swelling is expected in early post-operative days. The amount of swelling can be variable but often is quite dramatic. The main reason for swelling is oozing from sites of microfractures and osteophyte debridement, in addition to some oozing from soft tissue sites. Due to the effect of gravity, swelling is often noted to extend down to the foot and ankle region (depending on the amount of time spent in an upright position). Swelling may also be seen to accumulate into the thigh if the leg is propped up for a lot of the time in the first few days.
A tensor wrap from foot to thigh over the first few days can help to reduce some of the immediate postoperative swelling. Ice packs should be applied on knee to help reduce swelling. Your doctor may prescribe for you an anti-inflammatory medication in the early postoperative period, which can help control, some of the swelling and is also an effective adjunct for pain control.
If you notice significant swelling in the calf or thigh associated with a lot of posterior tenderness, this may be a sign that a DVT (blood clot) is developing. This warrants mentioning to your treating surgeon who will then decide whether a Doppler ultrasound study is indicated to help rule out a DVT.
What exercises should I be doing?
We recommend static quads exercise and ankle movement (for calf muscles) form first port-op day. Range motion exercises are started as tolerated from 7 days after the procedure. Straight leg raising and abductor strengthening is encouraged from 3 weeks onwards. After this individualized exercise program is provided to the patient depending upon his or her needs.
When can I go back to work?
Return to work is largely dependent on the type of work one is returning to and also how long it takes for the acute pain after surgery to settle.
A general guideline would be that most people returning to a sedentary type position (e.g. Office work, shopkeeping) should be able to return some time in the first 5 - 8 weeks post-op.
There are many factors that may allow some individuals to return to work sooner than this i.e. rapid resolution of pain post-op, a less pronounced swelling response, the ability to work from home, the possibility of modifications being made in the work environment i.e. ability to accommodate an initial return on crutches.
An individual returning to a more physically demanding labouring type position would likely return sometime between 4-6 months postoperatively.
Depending on the amount of distraction and the actual physical demands of one’s job, the time to return could be in some cases extended to even beyond 6 months. An earlier return might be possible if modifications could be made in the work environment to allow avoidance of heavy tasks and a more gradual return.
When can I drive?
It is possible for patients to drive sooner if it has been the left leg that has undergone surgery if there is access to a vehicle with an automatic transmission.
Driving should be generally delayed until one is off narcotic pain medication, and once reasonable mobility has returned. If the left leg is the operative leg, most patients should be able to drive approximately 6 weeks post-op. If on the other hand, the right leg has been the operative leg, driving should be delayed until full weight bearing has been commenced and the patient is ambulating well i.e. usually not before 3 months post-op.