A Cotton osteotomy is a foot surgery that corrects alignment problems in the midfoot by making a cut in the medial cuneiform, a small wedge-shaped bone on the inner side of your foot. The surgeon opens the cut from the top, inserts a bone graft to hold the gap, and this tips the inner edge of your foot downward into a more natural weight-bearing position. It’s most commonly performed as part of flatfoot reconstruction, and the full recovery takes three to six months.
What the Procedure Corrects
The Cotton osteotomy targets a specific problem called forefoot varus, where the inner border of the forefoot sits higher than the outer border when viewed from the front. In a healthy foot, three points of contact form a stable triangle: the heel, the base of the big toe, and the base of the little toe. When the medial column (the arch side) is elevated, that triangle collapses and the foot compensates by rolling inward, flattening the arch, and distributing weight unevenly.
The procedure is named after Frederick Cotton, who first described the technique. Contemporary indications include rigid forefoot varus (where the deformity can’t be corrected by hand), an elevated first ray contributing to limited big toe motion (hallux limitus), and residual forefoot misalignment after other rearfoot surgeries. It’s also used to correct iatrogenic elevation of the first metatarsal, meaning cases where a previous bunion surgery inadvertently raised the bone.
How the Surgery Works
The surgeon makes an incision over the top of the medial cuneiform and cuts through the bone while keeping the bottom surface intact, creating a hinge. The top of the cut is then opened like a book, and a wedge-shaped bone graft is inserted into the gap. This mechanically pushes the front part of the medial column downward, restoring contact between the ball of the foot and the ground.
Precision matters. The cut is made in a “safe zone” between the midpoint of the cuneiform and the level of the second tarsometatarsal joint, parallel to the bone’s natural joint surface. Placing the cut outside this zone risks damaging the Lisfranc ligament, a critical stabilizer of the midfoot. If the angle of the cut isn’t parallel to the joint surface, the remaining bone can fracture when the wedge is opened.
Each millimeter of graft thickness produces roughly 1.9 degrees of plantarflexion (downward tilt) of the medial column. This predictable ratio helps surgeons dial in the exact amount of correction needed. Most grafts come from donor bone (allograft), though some surgeons use bone harvested from the patient’s own hip or, in certain pediatric cases, from an accessory navicular bone that’s being removed during the same surgery. Both graft sources show comparable outcomes and successful bone healing.
Why It’s Chosen Over Other Procedures
When correcting medial column problems, surgeons generally choose between a Cotton osteotomy and a joint fusion (arthrodesis), such as a Lapidus procedure at the base of the big toe. The Cotton osteotomy preserves joint motion because the cut goes through the bone itself rather than across a joint. Research comparing the two approaches has found that the Cotton osteotomy is superior to first tarsometatarsal fusion for this reason: it maintains first ray mobility and offers a simpler correction.
Joint fusion becomes the better choice when there’s significant joint instability, hypermobility, arthritis, or a bunion with a wide angle between the first and second metatarsals. Surgeons rule out these conditions through clinical exam and X-rays before selecting the Cotton osteotomy. In the absence of joint disease, instability, or bunion deformity, the Cotton osteotomy is generally the preferred medial column procedure. It’s less invasive, quicker to perform, and carries a lower expected complication rate than fusion, though it’s almost always done alongside other procedures like a heel bone (calcaneal) osteotomy or tendon repair rather than as a standalone surgery.
Recovery Timeline
The first six weeks are non-weight-bearing. You’ll be in a cast or protective boot and will need crutches, a knee scooter, or another mobility aid to keep all pressure off the surgical foot. This period is critical for the bone graft to begin incorporating into the surrounding bone.
Around six to eight weeks, your surgeon will confirm healing on X-rays and begin transitioning you to partial weight-bearing. One study tracking radiographic outcomes found a statistically significant loss of correction between weeks six and ten, coinciding with the start of weight-bearing. This is a normal settling period, and surgeons account for it, but it underscores why following the gradual loading schedule matters.
From weeks 12 through 24, rehabilitation shifts to functional strengthening. Physical therapy during this phase typically includes resistance band exercises, single-leg balance work, calf raises (starting on both legs, progressing to one), stationary biking, treadmill walking, and eventually light agility drills. The goal by week 24 is a single-leg heel raise with good form, normal stair climbing, full ankle and foot strength, and a return to recreational activities.
Complications and Success Rates
The Cotton osteotomy has a relatively low complication profile. In a study of 71 procedures, the overall complication rate was 5.6%. The most notable risk is nonunion, where the bone graft fails to fully fuse with the surrounding bone. That same study reported a nonunion rate of about 4% (2 out of 47 cases with sufficient follow-up). Risk factors for nonunion in osteotomy procedures generally include higher body weight, smoking, and certain fixation methods.
Other potential complications include hardware irritation from the screw or plate used to stabilize the graft, graft migration or collapse, and numbness near the incision from a small sensory nerve that runs across the top of the midfoot. Serious complications like infection or deep vein thrombosis are possible with any foot surgery but are uncommon with this procedure. Most patients achieve solid bone union and measurable improvement in foot alignment, with the degree of correction closely matching the graft size used.