Alignment and Osteotomy
A knee osteotomy is a surgical procedure that corrects the alignment of the leg by precisely cutting and repositioning bone, shifting where body weight travels through the knee. It is one of the most powerful joint-preservation tools available for the right patient — and one of the most underused. For a meaningful subset of patients with knee pain, malalignment is not just a contributing factor to their problem. It is the root cause.
The mechanical axis of the leg is a straight line from the center of the hip to the center of the ankle. In a well-aligned knee, that line passes through the middle of the joint, distributing load evenly. In a bow-legged (varus) knee, it shifts inward, overloading the medial compartment. In a knock-kneed (valgus) knee, it shifts outward. Over time, this imbalance wears down the cartilage and meniscus on the overloaded side, producing pain, swelling, and arthritis.
The typical osteotomy patient is in their thirties or forties, too young for replacement but too symptomatic to ignore, with early to moderate arthritis on one compartment and an underlying malalignment that has never been addressed. An osteotomy corrects this by repositioning the bone to shift load away from the damaged side. The knee isn’t replaced; it’s mechanically optimized. For cartilage and meniscus procedures especially, this matters: placing a new graft into a malaligned knee is like installing new tires on a bent frame.
Some patients also have a rotational problem, where the femur is twisted inward (excessive femoral anteversion), pulling the kneecap off track and causing instability or anterior knee pain. A derotational osteotomy corrects this twist in ways that soft-tissue reconstruction alone cannot.
Video Education
In this video, Dr. Merritt discusses the importance of alignment in the setting of cartilage injuries to the knee. Alignment and osteotomy surgery often involves the treatment of cartilage injuries, both of which are talked about in detail.
Treatment Options
The specific osteotomy procedure I recommend depends on the direction and location of the malalignment, the compartment that is affected, and what additional procedures need to be performed at the same time. There are three main categories.
A high tibial osteotomy (HTO) corrects varus alignment — bow-leggedness — by cutting the proximal tibia and opening or closing a wedge to shift the mechanical axis toward the lateral (outer) compartment. This offloads the medial side, where the vast majority of varus-driven arthritis and cartilage damage occurs. HTO is one of the most durable joint-preservation procedures we have. Published long-term data show 92% survival at 5 years and 84% at 10 years – and 80-90% satisfaction rates in properly selected patient. These are not minor improvements; they represent years of active, lower-pain living that a replacement cannot offer to a 38-year-old.
A distal femoral osteotomy (DFO) corrects valgus alignment — knock-knees — by cutting the distal femur and shifting the axis toward the medial side. This offloads the lateral compartment, which bears the excess load in valgus malalignment. DFO is technically more demanding than HTO and carries a somewhat lower long-term survival rate, but it is the correct procedure when the deformity originates in the femur, and it is often essential for protecting lateral cartilage grafts and lateral meniscal procedures from premature failure.
A derotational osteotomy addresses torsional malalignment of the femur — specifically, excessive femoral anteversion, where the femur is twisted too far inward relative to the hip. This rotational deformity is a frequently overlooked driver of patellar instability and anterior knee pain. When the femur is internally twisted, the trochlear groove faces inward, making the patella inherently more likely to track laterally and dislocate. Correcting the anteversion with a derotational osteotomy improves patellar tracking at the structural level, which soft-tissue procedures like MPFL reconstruction cannot fully compensate for on their own. For patients with patella instability in the setting of increased femoral anteversion, addressing the rotation is essential for a durable outcome.
Precision Planning with NewClip Technology
A major differentiator in my approach to osteotomy is the use of NewClip technology for surgical planning. Before every osteotomy I perform, a CT scan of the full limb is obtained and sent to NewClip’s engineering team, where the complete surgical correction is planned digitally — calculating the exact angle of the wedge, the position of the cut, and the final mechanical axis before the patient ever comes to the operating room. Based on that plan, custom 3D-printed cutting guides are manufactured specifically for that patient’s anatomy. No two guides are identical. When I bring those guides to the OR, they fit only one patient’s bone and execute only that patient’s planned correction. The accuracy this provides is meaningfully better than freehand cutting or conventional instrumentation, and the planning process allows me to account for subtleties — bone geometry, joint line obliquity, concurrent procedure considerations — that would be impossible to optimize intraoperatively.
That last point matters particularly when I’m combining an osteotomy with an ACL reconstruction. NewClip’s planning software allows me to simulate the tunnel positions for the ACL graft alongside the osteotomy correction simultaneously, so the two procedures are fully coordinated before a single incision is made. This avoids a common technical pitfall where the osteotomy correction conflicts with the ACL tunnel position, and it makes combined osteotomy-ACL reconstruction a well-planned, single-stage procedure rather than a technically improvised one.
Osteotomy is also frequently combined with cartilage surgery — MACI, osteochondral allograft — and meniscus procedures. The alignment must be correct for these biological procedures to have a reasonable chance of surviving long-term. I view the osteotomy in these combined cases not as an optional add-on, but as the mechanical foundation on which the biological work is built.
The table below summarizes the key differences between HTO and DFO:
| High Tibial Osteotomy (HTO) | Distal Femoral Osteotomy (DFO) | |
|---|---|---|
| Alignment corrected | Varus (bow-legged) | Valgus (knock-kneed) |
| Bone cut location | Proximal tibia | Distal femur |
| Target compartment offloaded | Medial (inner) | Lateral (outer) |
| Common indications | Medial arthritis, meniscal deficiency, cartilage injury — medial side | Lateral arthritis, meniscal deficiency, cartilage injury — lateral side |
| 5-year survival | ~92% | ~70–75% |
| 10-year survival | ~84–85% | ~70–75% |
| Patient satisfaction (long-term) | 80-90% | High in well-selected patients |
Recovery Timeline
Injury to Surgery:
Osteotomy recovery is longer than most arthroscopic knee procedures because we are waiting for bone to heal — a cut made through the tibia or femur needs to knit back together before it can be fully loaded. That said, the recovery is manageable and well-structured, and for the right patient, the durability on the other end makes it entirely worthwhile.
Weeks 1–2:
The first priority is controlling swelling and managing pain. The knee is braced, and weight-bearing is limited. Ice, elevation, and a disciplined pain protocol are the main tools. Physical therapy begins within the first two weeks, focused on gentle range of motion and quad activation — preventing the muscle shutdown that follows any major knee procedure.
Weeks 2–8:
Protected weight-bearing with crutches continues through approximately six to eight weeks. The specific protocol depends on the procedure and what was done concurrently — if a cartilage procedure was also performed, the weight-bearing restrictions may be driven by cartilage healing rather than bone healing. At or around six to eight weeks, X-rays are obtained to confirm that the osteotomy site is healing appropriately before advancing to full weight-bearing.
Weeks 8–12:
As bone healing is confirmed, weight-bearing progresses to full. Crutches are weaned. Gait normalization and progressive strengthening become the focus of physical therapy. Most patients are walking well and functioning comfortably for daily activities by the three-month mark.
Months 3–5:
Strengthening intensifies. Cycling, swimming, and low-impact cardiovascular activity are introduced. Hip and core stability work — which is important for controlling knee alignment during activity — is a central part of PT in this phase.
Months 5–6:
Return to recreational and lower-impact sports. Running typically begins in a structured progression as strength testing allows. Most patients notice that the activity-related pain that drove them to surgery has improved substantially by this point.
Months 9–12:
Return to higher-demand sports and cutting or pivoting activity. If an ACL reconstruction was performed simultaneously, the ACL graft timeline governs return to sport, typically around nine months with criteria-based testing. Studies on HTO show an 86% return-to-sport rate, with most athletes returning at a level equal to or higher than their pre-symptom baseline — not just their pre-surgery baseline.
Hardware: osteotomy fixation uses a low-profile plate and screws. For most patients the hardware causes no issues and can remain permanently. A meaningful minority — roughly 20% — experience hardware irritation from the plate prominence, particularly with kneeling or direct pressure on the proximal tibia. In those cases, hardware removal is a short outpatient procedure typically done after the bone has fully healed, at one year or later.
The long-term durability of osteotomy compares favorably to alternatives for the right patient. HTO 5-year survival reaches 92%, 10-year survival 84%, with 97% patient satisfaction in ideal candidates at long-term follow-up. For a 35- to 45-year-old patient with malalignment-driven knee disease, osteotomy provides something no replacement can: time. Active, functional, lower-pain years while retaining the natural joint. And when a replacement does eventually become necessary — which is a real possibility I discuss honestly with every patient — a well-executed prior osteotomy does not compromise that surgery.
Knee Osteotomy Recovery Timeline
Drag the slider to explore each phase of your recovery
Select Your Procedure
Your surgeon will tell you which procedure applies. DFO (distal femoral osteotomy) realigns the thigh bone. HTO (high tibial osteotomy) realigns the shin bone. Closing wedge removes a wedge of bone so the surfaces touch — weight bearing from Day 1. Opening wedge opens the bone and fills with graft — toe-touch weight bearing for 6 weeks.
Injury and Surgery Resources
Discover detailed instructions and protocols to guide patients through Physical Therapy from Dr. Merritt.
Studies Cited
- Hui C, Salmon LJ, Kok A, et al. Long-term survival of high tibial osteotomy for medial compartment osteoarthritis of the knee. Am J Sports Med. 2011;39(1):64-70. PubMed
- Ekhtiari S, Haldane CE, de Sa D, et al. Return to Work and Sport Following High Tibial Osteotomy: A Systematic Review. J Bone Joint Surg Am. 2016. PubMed
- Radiographic changes and clinical outcomes after open and closed wedge high tibial osteotomy: a systematic review and meta-analysis. J Orthop Surg Res. 2019. PubMed
- Ren YM, et al. A meta-analysis of total knee arthroplasty following high tibial osteotomy versus primary total knee arthroplasty. Orthop Surg. 2020. PubMed
- Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Is Sport Activity Possible After Arthroscopic Meniscal Allograft Transplantation? Midterm Results in Active Patients. Am J Sports Med. 2016. PubMed
- Return to sport following distal femur osteotomy: a systematic review. J ISAKOS / Knee Surg Relat Res. 2022. PubMed
Common Alignment and Osteotomy Questions
Injury Information
A: Not necessarily — and this is one of the most important conversations to have before committing to a replacement if you are under 55 or 60. Knee replacement is an excellent procedure, but it is not designed for young, active patients. The implants have a finite lifespan, and revision surgery is significantly more complex than the primary. If you have malalignment and compartment-specific disease, osteotomy deserves a thorough evaluation before replacement is accepted as the only answer. I see these patients regularly, and the ones who come in for a second opinion are often very glad they did.
A: The ideal candidate is under 55, has a healthy BMI, has unicompartmental rather than global arthritis, and has a meaningful malalignment driving their symptoms. Age is not a hard cutoff, but the biological environment for healing and the expected activity demands factor into whether osteotomy or replacement makes more sense. Patients with inflammatory arthritis, severe global arthritis, or very poor bone quality are generally better served by replacement. The evaluation starts with a long-leg standing X-ray, MRI, and a thorough discussion of your goals and activity demands.
A: Possibly, and I tell patients this honestly. An osteotomy is a joint-preservation procedure, not a joint-elimination procedure. What it does is buy meaningful, active, lower-pain time — years of living well in your natural knee while the clock on replacement is pushed back. The data shows that HTO survivors who eventually convert to replacement have outcomes comparable to primary replacement patients. A well-executed osteotomy does not compromise the replacement surgery when the time comes. For a patient in their thirties or forties, that deferral is enormously valuable.
A: Yes, and in many cases this is what I recommend. Cartilage restoration procedures — MACI, osteochondral allograft — have significantly better long-term outcomes in a well-aligned knee. Performing the osteotomy at the same time as the cartilage procedure means the graft is immediately placed into a corrected mechanical environment, rather than continuing to absorb excess load from day one. The combined surgery is more complex and requires a carefully staged recovery, but for patients with both cartilage damage and malalignment, doing both together provides the best long-term result.
A: This is a conversation I have often, and it’s worth being direct. A meniscus transplant in a malaligned knee is placing new tissue into the same mechanical environment that destroyed the original meniscus. The data on that approach is sobering: 23% clinical failure at a mean of 7.3 years, 37% reoperation within 6.6 years, and only 47% of athletes returning to their prior level of sport. An osteotomy addresses the reason the meniscus wore out in the first place. For patients with malalignment and meniscal deficiency, I believe correcting the alignment is the right starting point — and the 97% long-term satisfaction data in well-selected HTO patients reflects that.
A: The most revealing image is a full-length standing X-ray of the leg from hip to ankle — what we call a long-leg alignment film. This shows the mechanical axis as a line from the center of the hip to the center of the ankle. If that line doesn’t pass through the center of the knee joint, you have meaningful malalignment. Standard knee X-rays alone can suggest alignment issues, but they don’t give you the full picture the way a standing long-leg film does. If you have knee pain on one side and haven’t had this image taken, it is worth asking for.
A: An osteotomy is a surgical procedure in which a bone is precisely cut and repositioned to correct the alignment of the limb. In the knee, this means changing where the body’s weight travels through the joint — shifting load away from the damaged compartment and onto the healthier side. The goal is to reduce pain, protect cartilage and meniscus tissue, and preserve the natural joint for as long as possible.
Surgery Information
A: Smoking significantly impairs bone healing and is one of the most common reasons osteotomies fail to heal properly — a complication called non-union. I generally do not perform elective osteotomies in active smokers, and I will ask you to stop for a meaningful period before and after surgery. If you are a smoker and considering this procedure, quitting is one of the most important things you can do to improve your outcome.
A: Not necessarily — the plate and screws can remain permanently and cause no issues for the majority of patients. Roughly 20% of patients experience some hardware irritation, typically from the plate prominence on the tibial side when kneeling or with direct pressure. In those cases, hardware removal is a straightforward outpatient procedure, typically done at one year or later once the osteotomy is fully healed.
A: Osteotomy is performed in the operating room under general or spinal anesthesia. Using the custom-printed NewClip cutting guide, I make a precise cut through the tibia or femur, open or close the correction to the planned degree, and fix the bone in its new position with a low-profile plate and screws. Surgery typically takes 60 to 90 minutes for an isolated osteotomy and longer for combined procedures. Most patients go home the same day or after an overnight stay. You will go home with a brace and crutches.
A: Yes, and for the right patient it should be. Varus malalignment increases the stress on an ACL graft significantly, and performing an ACL reconstruction in a varus knee without correcting the alignment increases the risk of graft failure. When I plan these combined cases using NewClip, I simulate both the osteotomy correction and the ACL tunnel positions simultaneously, so the two procedures are fully coordinated. The combined surgery is more demanding and the recovery is longer, but it is a far more durable solution than addressing only one problem at a time.
A: NewClip is a surgical planning technology I use for every osteotomy I perform. Before surgery, a CT scan of the full limb is obtained and sent to NewClip’s engineering team. They digitally plan the complete correction — calculating the exact wedge angle, cut position, and final mechanical axis for that individual patient. Based on that plan, they manufacture custom 3D-printed cutting guides specific to that patient’s bone anatomy. When I use those guides in the operating room, the correction has already been precisely determined and engineered. This is meaningfully more accurate than conventional cutting, and it allows me to plan complex combined cases — like an osteotomy combined with an ACL reconstruction — as a fully coordinated procedure before the first incision is made.
A: A derotational osteotomy corrects a rotational twist in the femur — specifically, excessive femoral anteversion, where the thighbone is turned inward more than it should be. This twist affects how the kneecap tracks and is one of the causes of patellar instability and chronic anterior knee pain that does not respond to soft-tissue surgery alone. I diagnose it with a physical exam and confirm it with CT imaging. Derotational osteotomy is often combined with MPFL reconstruction in patients with complex patella instability. It is an underappreciated and underperformed procedure that makes a significant difference in the right patient.
A: Both are osteotomies — bone cuts to correct alignment — but they address opposite deformities at different locations. A high tibial osteotomy (HTO) corrects varus alignment, meaning bow-legs, by cutting the upper tibia. It offloads the medial (inner) compartment. A distal femoral osteotomy (DFO) corrects valgus alignment, meaning knock-knees, by cutting the lower femur. It offloads the lateral (outer) compartment. The choice depends entirely on the direction of the deformity and where the damage is.
Post-Op Recovery
A: Low-impact activity — cycling, swimming — typically begins around four to five months. Running and recreational sport are usually back on the table at five to six months for isolated osteotomy cases. Return to cutting and pivoting sports, or any procedure that included an ACL reconstruction, is typically nine to twelve months with criteria-based testing. Studies show an 86% return-to-sport rate after DFO, with most patients returning at or above their pre-symptom performance level.
A: Typically six to eight weeks for an isolated osteotomy, at which point X-rays are obtained to confirm bone healing before transitioning to full weight-bearing. If a cartilage procedure was combined with the osteotomy, the non-weight-bearing period may be driven by cartilage healing rather than bone healing and could extend to eight to ten weeks. Your physical therapist will guide the transition based on your progress and imaging.
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