The relationship between chronic ankle instability and articular pathologies of the rearfoot and/ or ankle is well established with rates of concomitance reportedly as high as 97 percent.1 When evaluating 79 cases of chronic ankle instability, Hua and colleagues found that 75 out of 79 patients had synovitis and/or soft tissue impingement.2 Choi and coworkers have also noted poor outcomes with surgical repair of the lateral ankle ligaments in the presence of tibiotalar intra-articular deficits.1 There is also evidence that the inverse is also true. Lee and associates found poor clinical outcomes when addressing osteochondral lesions in patients with concomitant chronic lateral instability compared to those without.3
Researchers have also documented instability and intra-articular injury to the subtalar joint (STJ) occurring with lateral ankle instability, finding associated clinical STJ instability in approximately 10 to 15 percent of patients with chronic ankle instability.4 A surgeon who does not recognize that a patient suffers from both chronic ankle instability and rearfoot/ ankle intra-articular pathology may wind up recommending surgery that only partially treats the patient’s condition. This may lead to ongoing symptoms and the potential need for future subsequent procedures.
With this in mind, we routinely perform manual stress radiographs of the lateral ankle ligaments in patients presenting with suspected impingement of the subtalar and ankle joints. In a recent study, Jolman and colleagues touted the accuracy of ankle inversion stress radiographs as being equivalent to that of magnetic resonance imaging (MRI) when evaluating for injury to the lateral ankle ligaments.5 Anecdotally, we find that many patients with an “intact” anterior talofibular ligament (ATFL) on MRI clearly show instability on inversion stress imaging. This may be due to the MRI being a static exam that is unable to assess the function of the ligament.6
One of the challenges when performing rearfoot/ankle arthroscopy with the intent of a concomitant open lateral ankle stabilization is the clustering of incisions on the lateral ankle. This creates narrow skin bridges between the incisions that can result in poor healing outcomes. This area is also prone to neuritis associated with the intermediate dorsal cutaneous nerve, especially when open and arthroscopic incisions straddle both sides of the nerve.
A Viable Alternative To The Traditional Brostrom Incision
The traditional Brostrom incision is curvilinear and hugs the anterior lateral malleolus (see first photo above). This incision contributes to the problematic incision clustering over the lateral ankle as we previously described. The modified lateral approach is a linear obliquely-oriented incision from the lateral malleolus toward the anterior calcaneal process over the sinus tarsi (see second photo above). It is worth noting the wide skin bridge between the modified incision and the anterolateral ankle joint portal.
In addition to preventing clustering of incisions, the modified incision is considerate of the cutaneous nerves from an anatomic standpoint in comparison to the traditional curvilinear Brostrom incision. The nerves in question include the intermediate dorsal cutaneous nerve as well as the lateral cutaneous branch of the sural nerve. With the traditional incision type, any elongation of the incision may result in iatrogenic nerve injury. The modified sinus tarsi incision runs in line with the cutaneous nerves and may prove more protective.
Subtalar joint arthroscopic portals can easily incorporate into the modified sinus tarsi incision. After performing the initial incision, the surgeon carries dissection down to the extensor retinaculum. One can then create the STJ arthroscopic portals immediately through the extensor retinaculum (see third photo set above). This open dissection technique, in our experience, allows for improved tissue quality as there is less water logging of soft tissue in comparison to performing arthroscopy prior to the incision and dissection for subsequent open ankle stabilization.
Furthermore, the modified incision affords surgeons direct access to the talar body when performing lateral ankle stabilization that incorporates a suture-anchor into the body of the talus (see fourth and fifth photos above). Lastly, one can also extend or adjust the same incision to address other associated rearfoot and ankle pathologies such as peroneal rupture, STJ fusion and calcaneonavicular coalitions.
Rearfoot and ankle intra-articular pathology are highly associated with lateral ankle instability. To optimize patient outcomes, surgeons should address both processes when they are present. However, this may prove challenging and add risk due to incisional clustering on the lateral ankle. The aforementioned modified incisional approach allows for easy incorporation of both tibiotalar and subtalar joint arthroscopic portals, and is nerve-friendly from an anatomic standpoint. Minor adjustments or elongation of the sinus tarsi incision can also incorporate other commonly performed procedures such as peroneal tendon repair, STJ fusion and resection of calcaneonavicular coalition.
Dr. Boffeli is the Foot and Ankle Surgical Residency Program Director and Department Chair at Regions Hospital/HealthPartners Medical Group in St. Paul, Minn. Dr. Boffeli has disclosed that he has ownership in Surgical Design Innovations and is an investor in ExoToe, LLC.
Dr. Chang is a second-year resident with the Foot and Ankle Surgical Residency Program at Regions Hospital/HealthPartners Medical Group in St. Paul, Minn.
1. Choi WJ, Lee JW, Han SH, Kim BS, Lee SK. Chronic lateral ankle instability: the effect of intra-articular lesions on clinical outcome. Am J Sports Med. 2008;36(11):2167-2172.
2. Hua Y, Chen S, Li Y, Chen J, Li H. Combination of modified Broström procedure with ankle arthroscopy for chronic ankle instability accompanied by intra-articular symptoms. Arthroscopy. 2010;26(4):524-528.
3. Lee M, Kwon JW, Choi WJ, Lee JW. Comparison of outcomes for osteochondral lesions of the talus with and without chronic lateral ankle instability. Foot Ankle Int. 2015;36(9):1050-1057.
4. Hentges MJ, Lee MS. Chronic ankle and subtalar joint instability in the athlete. Clin Podiatr Med Surg. 2011;28(1):87-104.
5. Jolman S, Robbins J, Lewis L, Wilkes M, Ryan P. Comparison of magnetic resonance imaging and stress radiographs in the evaluation of chronic lateral ankle instability. Foot Ankle Int. 2017;38(4):397-404.
6. Seebauer, C, Hermann, J, Rump, JC. Ankle laxity: stress investigation under MRI control. AJR Am J Roentgenol. 2013;201(3):496-504.