What is the surgical technique for treating flexible flatfoot using calcaneal osteotomy?

Surgical Technique for Calcaneal Osteotomy in Flexible Flatfoot

Calcaneal osteotomy combined with other corrective procedures is the recommended surgical approach for symptomatic flexible flatfoot that has failed conservative treatment.

Indications for Surgery

• Surgery is indicated only when conservative treatment fails to relieve symptoms in flexible flatfoot 1
• Patients should have:
  • Persistent pain despite conservative measures
  • Functional limitations affecting daily activities
  • Progressive deformity

Preoperative Assessment

• Radiographic evaluation:
  • Anteroposterior and lateral weight-bearing radiographs
  • Key measurements:
    • Meary's angle (talo-first metatarsal angle)
    • Costa-Bertani's angle
    • Talonavicular coverage
    • Calcaneal pitch angle

Surgical Techniques for Calcaneal Osteotomy

1. Lateral Column Lengthening (Evans-Mosca Technique)

This is considered the gold standard for severe flexible flatfoot 2:

1. Surgical approach:

   • Lateral incision over the anterior process of the calcaneus
   • Identify and protect the peroneal tendons and sural nerve
   • Expose the calcaneocuboid joint

2. Osteotomy technique:

   • Make transverse osteotomy 1-1.5 cm proximal to the calcaneocuboid joint
   • Use oscillating saw with irrigation to prevent thermal necrosis
   • Complete the osteotomy with an osteotome

3. Correction and fixation:

   • Distract the osteotomy site with a lamina spreader (8-12mm)
   • Insert tricortical iliac crest bone graft or allograft wedge
   • Secure with K-wires or a small fragment plate and screws
   • Verify correction of forefoot abduction and heel valgus

2. Double Calcaneal Osteotomy

For severe cases with inadequate correction from lateral column lengthening alone 2, 3:

1. Lateral column lengthening (as described above)

2. Medial calcaneal shift osteotomy (can be done minimally invasively):

   • Small incision on the posterior-lateral heel
   • Transverse osteotomy of the calcaneal tuberosity
   • Medial displacement of the posterior fragment (average 8mm)
   • Fixation with cannulated screws

3. Advantages of minimally invasive approach:

   • Lower risk of wound complications
   • Reduced skin tension
   • Faster procedure with experience 2

Additional Procedures Often Combined with Calcaneal Osteotomy

1. Tibialis anterior tendon rerouting 4:

   • Indicated when dynamic supination is needed
   • Detach insertion of tibialis anterior
   • Reroute and reattach more laterally to improve foot position

2. Achilles tendon lengthening 1:

   • Indicated when ankle dorsiflexion is limited
   • Helps prevent recurrence of deformity
   • Can be performed percutaneously or as open procedure

3. Medial soft tissue procedures:

   • Medial reefing of talonavicular capsule
   • Spring ligament repair
   • Tibialis posterior advancement

Postoperative Management

1. Immobilization:

   • Non-weight-bearing cast for 6 weeks
   • Transition to weight-bearing boot for additional 4-6 weeks

2. Physical therapy:

   • Begin at 6-8 weeks post-surgery
   • Focus on:
     • Range of motion exercises
     • Progressive weight-bearing
     • Proprioception training
     • Strengthening of intrinsic foot muscles

3. Return to activities:

   • Progressive return to activities at 3-4 months
   • Full recovery may take 6-12 months

Expected Outcomes and Complications

Outcomes

• Clinical improvement measured by AOFAS scores typically improves from ~60 points preoperatively to >90 points postoperatively 5
• Radiographic correction:
  • Meary's angle improves from ~25° to ~1-5° 5
  • Talonavicular coverage improves significantly 6

Potential Complications

• Calcaneocuboid subluxation (reported in up to 51.5% with calcaneal lengthening) 6
• Wound complications (higher risk with open procedures)
• Nonunion (rare with proper technique)
• Overcorrection leading to lateral column pain
• Undercorrection with persistent deformity
• Sural nerve injury

Clinical Pearls

• Double calcaneal osteotomy provides better correction in severe cases than single osteotomy 3
• Minimally invasive techniques for the medial shift component reduce wound complications 2
• Ideal realignment is achieved when:
  • The heel is vertical in resting calcaneal stance position
  • The forefoot is parallel to the rearfoot in the frontal plane
  • The medial column is stabilized with elimination of forefoot abduction 3
• Additional soft tissue procedures should be considered based on specific deformity components but have not been proven to improve outcomes in all cases 1