Peroneal Tendoscopy Technique

Abstract

Background:

Peroneal tendoscopy is indicated for patients with persistent posterolateral ankle pain in which other intraarticular or extraarticular etiologies have been excluded. Physical examination findings and magnetic resonance imaging (MRI) evaluation are often equivocal, making direct visualization critical in characterizing the injury. Peroneal tendoscopy is a minimally invasive technique that is used to achieve this with little disruption to surrounding anatomy and minimal complications.

Indications:

We present a 57-year-old woman with 3 months of left posterolateral ankle pain and subluxation after a hyper-inversion injury despite conservative management. Magnetic resonance imaging showed irregularities of the peroneal tendons. Physical examination demonstrated swelling of the posterolateral ankle with tenderness to palpation and crepitus over the peroneal tendons and weakness with eversion. With inconclusive MRI findings and physical examination findings concerning for peroneal pathology, peroneal tendoscopy is indicated to evaluate the injury and indication for accompanying procedures.

Technique Description:

The patient is placed in a semi-lateral decubitus position using a bean bag. External anatomic landmarks are identified for a 2-portal approach with the “nick and spread” technique used to form the openings and avoid neurovascular structures and minimize retinacular disruption. The scope and a probe are used to manipulate the tendons for circumferential visualization and evaluation for tears, adhesions, tenosynovitis, and other pathologies. Dynamic testing of peroneal tendon tracking is completed. The decision is made to convert to a targeted open procedure based on the extent of peroneal pathology.

Results:

Clinical studies of patients undergoing peroneal tendoscopy have shown excellent results, with most patients reporting excellent outcomes and no recurrent subluxation events. Patients return to athletic activities as early as 3 to 4 months from surgery. Rare minor complications have been reported, including iatrogenic tendon damage and peroneal sheath rupture.

Discussion/Conclusion:

Posterolateral ankle pain may be difficult to diagnose and manage as it is often missed on MRI evaluation. Peroneal tendoscopy is a safe and efficacious procedure to evaluate and treat refractory posterolateral ankle pain secondary to peroneal pathology. Due to its minimally invasive technique, few complications have been reported, and most patients report good or excellent results.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Graphical Abstract

This is a visual representation of the abstract.

Video Transcript

The title of this presentation is Peroneal Tendoscopy Technique. This presentation will review common peroneal tendon pathologies and surgical indications for peroneal tendoscopy, including postoperative management and outcomes.

Peroneal pathology is suspected in patients with persistent posterolateral ankle pain after an ankle twisting injury.^1,2 After patients fail conservative management, magnetic resonance imaging (MRI) is often performed. Steel et al found the sensitivity of MRI in detecting tears of the peroneus brevis was 80%, 100% for tears of the peroneus longus, and 60% for tears of both tendons. ⁹ Difficulties in diagnosing peroneal tears on MRI is due to the “magic angle effect” from the sharp curve the peroneals take around the distal fibular groove.^4,8 The angulation of the magnetic beam causes a signal hyperintensity in the brevis; resulting in a 30/70 false positive rate of peroneus brevis tears read on MRI. ⁸ Equivocal preoperative findings often necessitate direct visualization of the peroneal tendons to determine the most appropriate surgical management.^1,2,8

Peroneal tendoscopy is an endoscopic technique in which an arthroscope is placed into the peroneal tendon sheath, allowing for direct evaluation of the tendons, retrofibular groove, and identification of normal anatomic variants.^1,2,5,6,7,10 As a result of improved accuracy, this technique allows for appropriate treatment with decreased complication rates as compared with open surgery.^3,9,10

Knowledge of peroneal anatomy is necessary prior to tendoscopy. The peroneus brevis and longus form the lateral compartment of the leg. The peroneal tendons run in a common peroneal sheath proximally with the peroneus longus posterolateral to the peroneus brevis, then travel in the distal fibular groove where the superior peroneal retinaculum provides stability and proper tendon tracking. Finally, the sheath bifurcates at the peroneal tubercle and the peroneus brevis inserts on the fifth metatarsal and the peroneus longus inserts on the medial cuneiform and base of the first metatarsal.

Preoperative work-up of a patient with sensations of ankle instability and a mechanism concerning for peroneal tendon injury includes a physical examination noting their standing alignment, gait, areas of palpation tenderness and/or crepitus along the peroneals, peroneal tendon tracking, and presence of any lateral ankle instability.^1,2,5,6,10 Ankle dorsiflexion and eversion followed by plantar flexion and inversion may demonstrate subluxation or dislocation of the peroneal tendons.^5,6,10

Peroneal tendoscopy is indicated in patients with pain or discomfort from maltracking or tearing of the peroneal tendons. It is also considered for diagnostic and therapeutic purposes in patients with recalcitrant posterolateral ankle pain with negative MRI findings, or when MRI findings suggest peroneal pathology, but the patient’s symptoms do not exactly correlate.^5-7,10

In our video and case presentation, we will first highlight the landmarks and anatomical locations of the 2 working portals. We will then focus on evaluating the tenosynovium, tendons, and retrofibular groove morphology. Finally, we will review the indications for debridement versus conversion to a limited open procedure based on pathology location.

We present a 57-year-old woman with a 3-month history of posterolateral left ankle pain after sustaining an inversion injury to the ankle. Physical examination was notable for swelling, tenderness to palpation, and crepitus along the course of the peroneal tendons. She also demonstrated weakness with ankle eversion.

The AP, lateral, and mortise radiographs from the patient’s initial injury were negative for any acute pathology. Magnetic resonance imaging was obtained with axial and sagittal T2 fat-saturation sequences notable for increased signal intensity within the peroneal tendons concerning but not definitive for a tear.

To perform peroneal tendoscopy, the patient is placed in a semi-lateral decubitus position on a beanbag, as often ankle arthroscopy to address additional pathology is done simultaneously. A tourniquet is placed on the upper thigh and elevated as needed for visualization. Arthroscopic pump pressure is set at a low-pressure setting of less than or equal to 40 mm Hg to prevent excessive fluid extravasation into the soft tissues. After sterile prepping and draping of the leg, the operative ankle is elevated 4 to 5 inches off the operative table with a sterile towel bump wrapped in Coban, so that the surgeon can freely move the scope and light cord without impingement with the table. A 2.7 mm 30° scope with inflow and outflow cannula is used with a 70° scope available if needed, along with small joint arthroscopy instruments and small (1.8-3.5 mm) oscillating shavers.

Anatomic landmarks are then identified, including the posterior cortical line of the distal fibular, distal fibular tip, calcaneofibular ligament, course of the peroneal tendons, and peroneal tubercle. The tendon sheath can be insufflated with saline prior to portal creation, depending on surgeon preference. Portals are localized with an 18-gauge needle, starting with the distal portal first. The distal portal is placed 2 cm inferior to the fibular tip and in line with the longitudinal axis of the fibula, avoiding iatrogenic injury to the superior peroneal retinaculum (SPR). In addition, the calcaneofibular ligament is at risk with the distal portal creation if the 11-blade is blindly buried into the skin. A nick of the skin with only the tip of the 11 blade is done to establish the portal opening with the subsequent spreading of subcutaneous tissue using a mosquito hemostat. This “nick and spread technique” avoids the mentioned structures and decreases neurovascular complications such as sural nerve injury.

After establishing the distal portal, the arthroscope is introduced and advanced past the superior retinaculum to visualize the vinculum, an arching soft tissue connection between the peroneus brevis and peroneus longus which is located proximal to the fibular groove and attaches to the dorsolateral fibular. The second or proximal portal then is established approximately 3 cm above the fibular tip and just below the vincula, using “nick and spread” technique.

Now, a probe can be used to systematically evaluate the brevis and longus tendons circumferentially from just superior to the fibular groove to the fibular tip. The surgeon can identify the brevis due to its lower lying muscle belly. The arthroscope is used as a retractor to push the longus out of the way as the brevis is evaluated with assistance of a probe and vice versa. The arthroscope can also be placed along the fibular so that undersurface of brevis can be better visualized. The peroneus brevis muscle belly is to the left and the peroneus longus tendon is to the right of the probe. Rotation of the light cord and slight movements of the scope allow visualization of the entire surface of both tendons.

Within this peroneal sheath “tunnel space,” the surgeon can confirm that there is no peroneal pathology, remove a low-lying muscle belly of the brevis (or accessory peroneus quartus or quintus if felt to be contributory to tendon mal tracking), debride thickened tenosynovitis, as seen here, and excise a peroneal tendon tear involving less than 50% of tendon substance. Once again, with the assistance of a probe, we can evaluate the peroneus longus. The arching structure to the right of the probe is the superior peroneal retinaculum.

The arthroscope is then switched to the proximal portal via use of a blunt trocar to prevent soft tissue injury. Further examination of the superior peroneal retinaculum and tendons from the fibular tip distally can now be performed. During the tendoscopy, the surgeon inspects tendons for pathology such as tears, tendinopathy, and tenosynovitis; the superior peroneal retinaculum and distal fibular labrum for disruption; fibular groove for morphology; peroneal muscle-tendon unit for excursion; and dynamic testing for peroneal tendon tracking. Endoscopic evaluation can proceed effectively all the way down to the peroneal tubercle level. Occasionally, an accessory portal can be placed anywhere along the sheath safely up to 6 cm proximal to fibular tip to access different portions of the tendons. Here the probe is visualized in the tear plane of the peroneus brevis.

In our patient, the peroneal tendon tear involved >50% of the tendon substance, and peroneal maltracking was noted so the decision was made to proceed with an open tendon repair and fibular groove deepening based on the tendoscopy findings. ⁵ The pickups are pointing to the tear, and the Crile retractor is around the peroneus longus. We are now checking tracking of the repaired tendons and final repair with superior peroneal retinaculum advancement.

Common intraoperative findings include tenosynovitis, peroneal tendon tearing, and inadequate retrofibular groove depth causing peroneal maltracking.^1,2,7 While peroneal tenosynovitis can be managed with debridement using an arthroscopic shaver, if the tear involves greater than 50% of the tendon cross-sectional area. ⁵

Here, we will present a few pearls to make the procedure less difficult. First, it is important to place the portal incisions in line in consideration of a potential open incision that connects the two portals. When making portals, use the “nick and spread” technique to avoid neurovascular and soft tissue complications. Proper portal placement is key to success. To aid the visualization throughout the surgery, we suggest making the proximal portal just off the posterior border of the fibular, so entry is more anterolateral or direct lateral. Also, the peroneal sheath is quite superficial, and so it is important to remember not much force or depth is needed to enter. As there are no instruments specifically designed for peroneal tendon or retinacular repairs, the limited space within the tunnel makes it difficult to place sutures and do arthroscopic knot tying techniques, often necessitating an open repair of indicated structures.

There are rare complications reported with peroneal tendoscopy. Peroneal sheath rupture or tearing may occur leading to impaired visualization and extravasation of endoscopic fluid. ⁷ Iatrogenic peroneal tendon damage may occur during insertion of instruments into the tendon sheath. ⁷ In addition, due to the proximity of the sural nerve to the distal portal, iatrogenic injury is possible.

Regarding the postoperative management, as the superior peroneal retinaculum is not disrupted with tendoscopy, patients are splinted 2 to 5 days and then transition to weightbearing as tolerated in a tall controlled ankle-motion (CAM) walking boot. Early recovery is 4 to 6 weeks and 6 to 10 weeks for return to sports. ⁹ Conversion to an open procedure such as a peroneal tendon repair may alter the postoperative management. Our patient required peroneal tendon repair, excision of a low-lying muscle belly, along with distal fibular groove deepening so weightbearing was restricted for 3 weeks to protect the retinacular repair.

Ultimately, peroneal tendoscopy is a minimally invasive technique allowing for improved cosmesis and faster rehabilitation as compared with an open procedure. At a mean follow-up of 2 years, Lui ⁶ demonstrated that patients who underwent peroneal tendoscopy for recalcitrant retrofibular pain without peroneal subluxation were able to return to full activity. Similarly, Kennedy et al ³ showed that over a 2-year period, patients undergoing peroneal tendoscopy had significant increases in their Foot and Ankle Outcomes Scores and Short Form-12 scores, and patients can often return to sports within 6 to 10 weeks. ⁹ These studies provide continued support the use of peroneal tendoscopy to manage chronic posterolateral ankle pain.