Knee Osteotomy: Buying Time Before Replacement
Knee osteotomy is a joint-preserving procedure that realigns the leg to shift weight away from a damaged compartment of the knee to a healthier one. It is most commonly performed for younger, active patients with unicompartmental (one-sided) arthritis who are too young for knee replacement.
Why Alignment Matters
The knee has three compartments: medial (inner), lateral (outer) and patellofemoral (kneecap). When one compartment is arthritic while the other two are healthy, the problem is often compounded by leg malalignment. A varus (bow-legged) alignment overloads the medial compartment. A valgus (knock-kneed) alignment overloads the lateral compartment.
Osteotomy corrects this malalignment by cutting and repositioning the bone, redistributing load to the healthy cartilage. Think of it as moving weight from a worn tire to one with good tread.
Types of Knee Osteotomy
Osteotomy Types and Indications
| Type | Correction | Best For | Fixation |
|---|---|---|---|
| High tibial osteotomy (HTO) | Varus to neutral or slight valgus | Medial compartment arthritis in active patients | Plate and screws |
| Distal femoral osteotomy (DFO) | Valgus to neutral | Lateral compartment arthritis | Plate and screws |
| Opening wedge | Bone is cut and opened, gap filled with graft or wedge | Most common modern technique, precise correction | Locking plate |
| Closing wedge | Bone wedge removed, gap closed | Faster healing (bone-to-bone), but shortens the limb slightly | Plate or staples |
Who Is a Good Candidate
- Age: Typically 30 to 60 years old. Patients over 60 are generally better served by partial or total knee replacement.
- Activity level: Active patients who want to continue running, hiking, manual labor or sports. Replacement implants have activity restrictions that osteotomy does not.
- Isolated compartment disease: Arthritis confined to one compartment with healthy cartilage in the other two.
- Correctable deformity: Malalignment of 5 to 15 degrees that can be corrected to neutral or slight overcorrection.
- BMI under 30: Higher BMI is a relative contraindication due to increased failure rates and wound complications.
- Non-smoker: Smoking significantly impairs bone healing and increases non-union risk.
Surgical Procedure and Recovery
The most common technique today is a medial opening-wedge high tibial osteotomy (HTO). The surgeon makes a cut in the upper tibia (below the knee), gradually opens the bone to the calculated correction angle, then fixes it with a locking plate. The gap fills with new bone over 8 to 16 weeks.
HTO Recovery Timeline (Weeks)
Osteotomy vs Partial Knee Replacement
Both procedures address unicompartmental arthritis. Here is how they compare:
| Factor | Knee Osteotomy | Partial Knee Replacement (UKA) |
|---|---|---|
| Activity after surgery | No restrictions (running, pivoting, impact allowed) | Typically advised to avoid high-impact activities |
| Recovery to full weight-bearing | 8 to 12 weeks | 2 to 4 weeks |
| Implant longevity | 70-90% at 10 years (native joint preserved) | 85-90% at 10 years (implant dependent) |
| Revision to TKR if needed | Standard TKR, no additional complexity | Revision can be more complex |
| Ideal patient age | 30 to 55 | 55 to 75 |
| BMI limitation | Best under 30 | Less sensitive to BMI |
The key advantage of osteotomy is that it preserves the native joint and all ligaments, keeping options open for the future. If the osteotomy eventually fails, a standard total knee replacement is still possible without the added complexity that revision of a partial knee implant can involve.
Long-Term Outcomes
A meta-analysis of 3,195 HTOs found the pooled 10-year survival rate was 84%, with the majority of failures converting to total knee replacement without complication. Predictors of better long-term outcomes include correction to 3 to 5 degrees of valgus, patient age under 50, BMI under 30 and compliance with post-operative rehabilitation.
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Message Us on WhatsAppFrequently Asked Questions
How long does a knee osteotomy last before I need a replacement?
Studies tracking high tibial osteotomy patients long-term report 10-year survival rates of 70 to 90%, meaning 70 to 90% of patients have not converted to total knee replacement at 10 years. At 15 years, survival drops to 60 to 75%. Patient selection matters: younger patients with isolated medial compartment disease and a correctable deformity have the best longevity.
Is knee osteotomy a bigger surgery than knee replacement?
The surgical time is similar (60 to 90 minutes), but osteotomy involves cutting and repositioning bone, which requires a longer recovery for bone healing (6 to 12 weeks protected weight-bearing versus immediate weight-bearing after many knee replacements). However, osteotomy preserves your native joint, which matters for longevity in younger, active patients.