A Closer Look At The Mini-Open Ankle Arthrodesis
Joint sparing procedures include total ankle arthroplasty, distraction arthrodiastasis and allograft total ankle replacement. However, the gold standard is still ankle arthrodesis.
Traditional exposure for ankle arthrodesis has been through the open transfibular approach. This approach usually involves a fibular takedown osteotomy but researchers have described a medial malleolar approach.1 Unfortunately, this technique has the disadvantages of a larger skin incision that can lead to wound dehiscence and increased risk of postoperative infections, resection of the fibula and possible disruption of the vascular supply.
In order to attempt to decrease the aforementioned disadvantages, arthroscopic ankle arthrodesis gained popularity. 2-5 This surgical technique has advantages of a high union rate with an early fusion time. It does have the disadvantages of a steep learning curve and the use of mechanical burrs to prepare the joint surfaces that can lead to thermal necrosis.
Mini-open ankle arthrodesis combines the advantages of both open and arthroscopic ankle arthrodesis while minimizing the disadvantages. It preserves the fibula and the peroneal artery, and eliminates the need to use burrs to prepare the surfaces, which allows for earlier union. Since it has smaller incisions, it reduces the risk of wound dehiscence and postoperative infection.
What Are The Indications For The Procedure?
An initial indication for mini-open ankle arthrodesis was ankle arthritis with minimal bone loss and minimal deformity that had failed conservative treatment. With experience, the indications have broadened for this technique.
I have found that one can correct ankle deformities through the mini-open approach if the deformities meet certain criteria. I now use the mini-open approach in patients with varus or valgus deformity if the ankle range of motion is not rigid. I find that once you debride the remaining cartilage, you can correct any varus or valgus deformity. The surgeon can treat recurvatum and procurvatum deformities more appropriately through an open transfibular approach.
The limited skin incisions make the mini-open ankle arthrodesis a better option for patients with dermatologic conditions, diabetes, autoimmune disorders, vascular conditions and previous incisions from prior surgeries. I still use a traditional open approach for rigid deformities, recurvatum or procurvatum of the ankle, talar avascular necrosis, nonunion revision or in ankles with significant bone loss.
A Guide To Surgical Technique
The incisional approach for the mini-open ankle arthrodesis was originally described as anterior-medial and anterior-lateral incisions at the ankle approximately 1.5 to 2.0 cm in length. One would make the anterior-medial incision just medial to the tibialis anterior tendon and make the anterior-lateral incision just lateral to the peroneus tertius.
With increased experience, I have found that one can lengthen the anterior-lateral incision slightly in the proximal direction in order to help facilitate screw placement. Carry dissection down to the anterior capsule and incise the capsule to expose the ankle joint.
The surgeon should remove osteophytes and loose bodies in order to help with exposure of the joint. Debride both the medial and lateral gutters at this time. Visualize the joint by placing a smooth laminar spreader into one of the incisions. This allows good exposure to the joint through the second incision.
Debride the cartilage using a combination of osteotomes and curettes. Straight curettes can debride the cartilage along the anterior tibia and talus. One can use curved osteotomes to facilitate the removal of cartilage from the middle and posterior tibial plafond. Take care not to penetrate the posterior ankle capsule. One can use curved ring curettes for the remaining cartilage on the talus.