Subtalar Joint Preparation Using 2 Portal Posterior Arthroscopic Technique vs Sinus Tarsi Open Approach: A Cadaveric Study

Abstract

Category: Ankle, Arthroscopy, Basic Sciences/Biologics Introduction/Purpose: Subtalar fusion is the treatment of choice for subtalar arthritis when conservative management fails. Subtalar fusion can be done through open approach or arthroscopic technique. Arthroscopic technique is associated with rapid recovery; however, it requires adequate training and skill. Arthroscopic technique can be done through lateral or posterior portals. Sometimes it may be necessary to use accessory portal to open or distract the joint for adequate joint preparation. Use of accessory portal may result in injury to the neurovascular structure. Whatever the technique, one of the most important aspects of fusion is adequate preparation of the joint. Aim of our study is to compare the preparation of subtalar joint using sinus tarsi open approach and posterior subtalar scopy using 2 portal technique in cadaveric specimens. Methods: We used 20 below knee fresh-frozen cadaver legs for this cadaveric study. Subtalar joints of ten specimens were prepared through the lateral approach, while the remaining ten joints were prepared using sinus tarsi incisions. After the completion of preparation, all ankles were dissected open, photographic images of calcaneal and talar articular were taken. (Image)Surface areas of each articular facet and prepared area of the talus, distal tibia, and distal fibula were measured and analyzed. Results: Open technique results in better preparation of joint surface in calcaneus and overall. While open technique results in preparation of 92% joint surface (combined talus and calcaneus), arthroscopic technique results in in 80% of joint surface. Open technique results in better preparation of calcaneus (79vs 94%). The anterolateral corner of calcaneus was difficult to be reached using the scope and unprepared in most cases. There was no significant difference in the preparation of talar articular surface. (Table 1) Conclusion: Open sinus tarsi results in more joint preparation compared to 2 portal posterior arthroscopic technique. The less amount of joint preparation in arthroscopic technique is mostly due to less preparation of AL corner. Of calcaneus. When using posterior arthroscopic technique, it is advisable to use accessory portal to distract the joint to aid in adequate preparation.