Lapidus arthrodesis is a surgical procedure performed to correct moderate to severe hallux valgus (bunion) deformities. The operation involves fusing the first tarsometatarsal (TMT-I) joint, which connects the first metatarsal bone to the medial cuneiform bone in the midfoot. This technique helps stabilize the joint, realign the big toe, and relieve pain caused by hypermobility or instability at the base of the first metatarsal.
How Common It Is and Who Gets It? (Epidemiology)
Lapidus arthrodesis is a commonly performed procedure for patients with significant bunion deformities, especially when hypermobility at the first TMT joint is present. It is most frequently indicated for adults with moderate to severe hallux valgus, recurrent bunions after previous surgery, or flatfoot deformity with first-ray instability. It is less commonly used in mild bunions where simpler osteotomies may be sufficient.
Why It Happens – Causes (Etiology and Pathophysiology)
Hallux valgus develops from a combination of biomechanical, structural, and hereditary factors. Excessive mobility at the first TMT joint allows the first metatarsal to drift medially and rotate, causing the big toe to deviate toward the second toe. Over time, the bunion enlarges, leading to pain, inflammation, and difficulty wearing shoes. Lapidus arthrodesis corrects this by fusing the unstable TMT joint, preventing excessive motion and providing a solid foundation for the first metatarsal.
How the Body Part Normally Works? (Relevant Anatomy)
The first TMT joint plays a critical role in maintaining the stability and alignment of the medial column of the foot. It connects the first metatarsal to the medial cuneiform and allows limited gliding motion for normal walking. When this joint becomes hypermobile, it destabilizes the arch and contributes to the development of hallux valgus. By fusing the joint, Lapidus arthrodesis stabilizes the medial column, restores alignment, and reduces the deforming forces on the big toe.
What You Might Feel – Symptoms (Clinical Presentation)
Patients typically report pain at the base of the big toe and along the inner edge of the foot. Symptoms may include redness, swelling, and difficulty fitting into shoes due to the protruding bunion. Some patients also experience instability or weakness when standing or walking. In more advanced cases, the big toe may overlap the second toe or cause discomfort beneath the other metatarsal heads.
How Doctors Find the Problem? (Diagnosis and Imaging)
Diagnosis is based on a physical examination and radiographic measurements. The intermetatarsal angle (IMA) between the first and second metatarsals and the hallux valgus angle (HVA) are used to determine severity. Mild deformities have lower angles, while severe cases may show IMA >16° and HVA >31°. Weight-bearing X-rays help assess joint alignment and hypermobility. MRI or CT scans may be used to evaluate arthritis or associated deformities.
Classification
Hallux valgus deformities are classified as mild, moderate, or severe based on radiographic measurements. Lapidus arthrodesis is indicated for moderate to severe deformities or when hypermobility at the TMT joint contributes to the bunion formation.
Other Problems That Can Feel Similar (Differential Diagnosis)
Conditions that can mimic hallux valgus include hallux rigidus (arthritis of the big toe joint), tailor’s bunion (fifth metatarsal deformity), sesamoiditis, and gout. These conditions can usually be distinguished through examination and imaging.
Treatment Options
Non-Surgical Care
Mild deformities can be treated conservatively with shoe modifications, padding, toe spacers, and orthotics that reduce pressure on the bunion. Anti-inflammatory medications and ice help control pain and swelling. However, these treatments do not correct bone alignment.
Surgical Care
Lapidus arthrodesis (CPT 28740) is performed when conservative care fails. The surgery aims to realign the first metatarsal, stabilize the medial column, and correct the bunion deformity by fusing the first TMT joint.
Step-by-step procedure:
- The patient is placed under general or regional anesthesia.
- A small incision is made on the inside of the foot to expose the first TMT joint.
- The articular cartilage is removed, and the bone surfaces are prepared for fusion.
- The first metatarsal is repositioned into proper alignment.
- The joint is fixed using screws or plates to hold the bones together.
- If needed, additional soft tissue procedures or osteotomies are performed to fine-tune correction.
Recovery and What to Expect After Treatment
After surgery, the foot is protected in a cast or boot. Patients typically remain non-weight-bearing for 6–8 weeks, followed by partial weight-bearing as X-rays confirm healing. Physical therapy begins after fusion stability is confirmed to restore ankle motion and improve strength. Full recovery may take 3–6 months, depending on healing and activity level.
Possible Risks or Side Effects (Complications)
The most common complication is nonunion, where the bones fail to fuse completely, occurring in about 5–10% of cases. Other potential risks include infection, nerve irritation, hardware discomfort, and transfer metatarsalgia, where pain shifts to the lesser metatarsals. Recurrence of the bunion can occur if postoperative alignment is not maintained.
Long-Term Outlook (Prognosis)
The long-term success rate of Lapidus arthrodesis is high, with studies reporting pain relief and deformity correction in 85–95% of cases. Once fusion is achieved, recurrence is rare. The procedure provides lasting structural stability, allowing most patients to return to daily activities and wear normal shoes comfortably.
Out-of-Pocket Cost
Medicare
CPT Code 28740 – Lapidus Arthrodesis (Arthrodesis, Midtarsal or Tarsometatarsal, Single Joint): $189.82
Medicare Part B covers 80% of the approved cost for this procedure once your annual deductible has been met, leaving you responsible for the remaining 20%. Supplemental Insurance plans such as Medigap, AARP, or Blue Cross Blue Shield typically cover that remaining 20%, minimizing or eliminating out-of-pocket expenses for Medicare-approved surgeries. These plans coordinate with Medicare to close the coverage gap and reduce patient responsibility.
If you have Secondary Insurance, such as TRICARE, an Employer-Based Plan, or Veterans Health Administration coverage, it acts as a secondary payer. These plans usually cover any remaining coinsurance or small deductibles, which typically range between $100 and $300, depending on your plan and provider network.
Workers’ Compensation
If your Lapidus arthrodesis is needed due to a work-related injury or progressive deformity, Workers’ Compensation will cover all associated costs, including surgery, rehabilitation, and follow-up visits. You will not have any out-of-pocket expenses, as the employer’s insurance carrier pays all approved charges directly.
No-Fault Insurance
If your Lapidus fusion procedure is required because of an automobile accident or traumatic injury, No-Fault Insurance will generally cover the entire cost of your treatment, including surgery and postoperative care. The only potential out-of-pocket cost may be a small deductible or co-payment based on your insurance policy.
Example
David Miller underwent a Lapidus arthrodesis (CPT 28740) to correct severe bunion deformity and first tarsometatarsal joint instability. His estimated Medicare out-of-pocket cost was $189.82. Since David had supplemental insurance through Blue Cross Blue Shield, his remaining balance was fully covered, leaving him with no out-of-pocket expenses for the surgery.
Frequently Asked Questions (FAQ)
Q. What is Lapidus arthrodesis?
A. It is a surgical fusion of the first tarsometatarsal joint performed to correct severe bunions and stabilize the foot.
Q. Who is a candidate for this procedure?
A. Patients with moderate to severe hallux valgus, hypermobility at the first TMT joint, or recurrent bunions after previous surgery are good candidates.
Q. How long does recovery take?
A. Most patients can begin weight-bearing after 6–8 weeks, with full recovery typically within 3–6 months.
Q. Will I lose motion in my foot?
A. Motion is lost at the fused joint but preserved in other joints, allowing normal walking once healing is complete.
Q. How successful is the surgery?
A. Fusion success rates exceed 90%, with significant improvement in alignment, pain, and function.
Summary and Takeaway
Lapidus arthrodesis is a reliable surgical technique for correcting severe bunions caused by instability at the first tarsometatarsal joint. By fusing this joint, the procedure restores alignment, relieves pain, and prevents recurrence. It is especially suitable for patients with moderate to severe deformities or failed previous bunion surgeries. With modern fixation methods and structured rehabilitation, most patients achieve excellent long-term outcomes.
Clinical Insight & Recent Findings
A recent study reviewed the evolution of Lapidus arthrodesis, a procedure used to correct moderate to severe hallux valgus (bunion) and first-ray hypermobility. The review found that modern techniques—such as using locking plates, compression screws, and even arthroscopic approaches—have made the surgery more stable, reduced the risk of nonunion, and allowed for earlier weight-bearing.
While the Lapidus procedure remains technically demanding, it provides powerful triplanar correction (addressing deformity in three planes) and long-term stability when performed correctly. Studies now show union rates approaching 98–100% with improved fixation methods, and even athletes are increasingly able to return to activity.
The review concludes that with careful patient selection and modern fixation, Lapidus arthrodesis remains one of the most effective and durable options for correcting complex bunion deformities. (“Study on modern Lapidus arthrodesis techniques – see PubMed.“)
Who Performs This Treatment? (Specialists and Team Involved)
The procedure is performed by an orthopedic foot and ankle surgeon or a podiatric surgeon trained in forefoot and midfoot reconstruction. The team includes an anesthesiologist, surgical nurses, and physical therapists for postoperative care.
When to See a Specialist?
You should see a foot and ankle specialist if you have persistent bunion pain, difficulty wearing shoes, or foot instability that has not improved with conservative measures.
When to Go to the Emergency Room?
Seek immediate care if you experience severe pain, swelling, redness, or signs of infection after surgery, or if you cannot bear weight on the foot.
What Recovery Really Looks Like?
The first several weeks require strict non-weight-bearing to protect the fusion site. Once healing progresses, gradual walking begins with a boot or supportive shoe. By 12 weeks, most patients resume normal activities, with improved alignment and reduced pain.
What Happens If You Ignore It?
Untreated hallux valgus can worsen over time, leading to chronic pain, difficulty walking, and deformity progression. Severe cases can cause arthritis and joint instability that may require more complex reconstructive surgery.
How to Prevent It?
Wearing supportive shoes, avoiding high heels, and using orthotics to control foot mechanics can reduce strain on the big toe joint and prevent deformity progression.
Nutrition and Bone or Joint Health
A diet rich in protein, calcium, and vitamin D supports bone fusion and healing. Avoid smoking and maintain good blood circulation to promote recovery and reduce nonunion risk.
Activity and Lifestyle Modifications
After recovery, patients should wear well-fitting shoes with adequate support and avoid high heels or narrow toe boxes. Regular exercise and stretching help maintain mobility in surrounding joints and prevent stiffness.
Dr. Mo Athar
