High Tibial Osteotomy
High tibial osteotomy (HTO) is a type of surgery where a cut is made towards the top of the shin bone (the tibia) to slightly shift the axis of weight bearing.
The procedure realigns weight distribution to relieve pain. It’s generally recommended in patients under 55 affected by single (medial only) osteoarthritis of the knee.
HTO is a joint-preserving surgery that maintains existing knee structures and slows the progression of arthritis in the knee. This allows young individuals to continue with their usual work, activities, and hobbies without the limitations imposed by a knee replacement surgery.
Should the arthritis deteriorate, total knee replacement may still be required in the future.
Dr Sunil Reddy may also advise HTO for patients who have sustained a ligament injury as a standalone procedure or more commonly in association with ligament reconstruction.
X-ray images of HTO fixed with plate and screws.
Procedure
HTO can be performed under general anaesthetic or spinal anaesthetic where the patient remains awake during the procedure. The patient lies on his or her back and blood flow to the leg being operated on is restricted with a tourniquet.
Before the main procedure begins, a knee arthroscopy is often conducted to assess the cartilage and meniscal and ligament structures, and to remove any loose cartilage.
A 6-7cm incision to the shin is made, and a precise osteotomy cut to realign the knee is made and fixed with a plate. Bone graft substitute or artificial bone graft is used to fill the gap created. Sometimes, bone graft from your iliac crest may be used to enhance osteotomy healing.
The surgery generally takes around 60-90 minutes, with the patient often able to leave the hospital within 24-48 hours.
HTO (medial opening wedge) – things you need to know
Recovery
Following surgery, only touch weight bearing (no weight passing through the limb) is allowed for six weeks.
A hinged knee brace should be worn for at least four weeks. Range of movement will be locked at 0-60 degrees for two weeks then to 0-90 degrees until six weeks after surgery. The brace can be removed to shower and twice daily for exercises as advised by Dr Reddy and your therapist.
You may return to sedentary/desk jobs at three weeks, but manual/heavy work cannot be performed for 12 weeks. Return to sports would take six to 10 months.
Dr Reddy does not recommend or perform medial opening wedge HTO in chronic, heavy smokers who are not willing to quit as this results in a much higher-than-acceptable risk of non-union or the osteotomy site not healing. Obesity and involvement of other knee compartments are other relative contraindications to the procedure.
Overview of risks
Risks of knee surgery include but are not limited to:
- Nerve injury leading to long-term numbness.
- Blood clots (deep vein thrombosis / pulmonary embolism) in the legs and/or lungs.
- Failure of the graft requiring reoperation.
- Persistent pain.
- Joint stiffness.
Problems with screws that may be used to fix the osteotomy.