A Closer Look At The Distal Tibial Osteotomy For Ankle Varus

Jeffrey E. McAlister, DPM, and Terrence M. Philbin, DO

These authors discuss the distal tibial osteotomy and present a case study of a 23-year-old female with concomitant ankle varus and post-traumatic ankle pain.

Distal tibial osteotomies are powerful corrective procedures surgeons often use for realignment of various ankle deformities. A 23-year-old healthy female presented with a posteromedial talar dome lesion following a fall. The lesion was 11 mm x 17 mm x 5 mm. The patient had no significant past medical or surgical history. She was taking no medications, did not use tobacco and drank alcohol on occasion at the time of surgery.

   We sought to correct her medial talar dome lesion, stabilize her cartilage and give her support with a lateral soft tissue correction. Then if she did well, we would revisit the operative limb with a corrective tibial osteotomy.

   In August 2011, the patient underwent an ankle arthroscopy with extensive debridement, a medial malleolar osteotomy and debridement of the talar dome lesion with application of a juvenile hyaline cartilage implant. During this same operation, she also had an open modified lateral ankle stabilization procedure. After doing well through her recovery process from the primary procedure, she was ready for her secondary corrective procedure: a distal tibial osteotomy.

   In May 2012, we performed an ankle arthroscopy to debride any synovitis and subsequently performed an opening wedge tibial osteotomy. From the tibiotalar angle on an AP ankle radiograph, we determined the preoperative angular correction to be approximately 9 degrees. After an extensive debridement of her ankle joint through the standard anteromedial and anterolateral portals, we made an 8 cm longitudinal skin incision proximally from the medial malleolus. When deepening the dissection, one should carefully avoid the great saphenous vein and saphenous nerve, which usually lie in the anterior portion of the incision.

   We created full-thickness flaps to the level of the periosteum at the site of the proposed osteotomy. Using a Cobb elevator, we made a periosteal flap parallel to the skin incision. Since the deformity’s center of rotation and angulation (CORA) is at the level of the ankle joint, we normally perform our osteotomy about 4 cm proximal to the medial malleolar tip. Then we inserted a Steinmann pin under fluoroscopy proximal and distal to the proposed osteotomy. Before creating the osteotomy, we used Hohmann retractors to carefully avoid cutting the posterior tibial tendon and the posterior neurovascular bundle.

   Using a wide saw blade, we created an osteotomy, aiming slightly proximal to distal while extending the cut from medial to lateral under fluoroscopy. The lateral tibial cortex was intact so as to not destabilize the distal fragment. Using the wide Hintermann distractor, we were able to open the medially based wedge to our desired length while visualizing it directly under fluoroscopy. Once the ankle joint was congruent, we cut our allograft femoral neck just above the desired width, accounting for resorption and the width of the saw blade. After inserting the bone graft with a tamp and mallet, we removed the pins and applied a medial locking plate.

   We closed the periosteum and subcutaneous tissues in standard fashion with absorbable sutures and the skin with interrupted nonabsorbable sutures. We then placed the operative limb in a well-padded posterior splint.

   The patient remained non-weightbearing for six weeks in a cast and subsequently wore a weightbearing fracture boot for a month. She then transitioned to supportive shoes with custom-molded orthoses. Her follow-up consisted of serial radiographs until radiographic healing of at least two cortices was visible.

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