Scoping Out Ankle Impingement

Abstract

Background:

Ankle impingement is common in athletes, especially in running, jumping, and cutting activities. We present 2 clinical cases of impingement, anterior (AAI) and posterior (PAI), plus subfibular, demonstrating the utility of ankle arthroscopy and hindfoot endoscopy techniques.

Indications:

AAI presents with pain at terminal dorsiflexion, tenderness over the anterior joint, and pain with passive hyperdorsiflexion. PAI presents with pain on repetitive plantarflexion, tenderness over the posterior talar process, and pain with passive hyperplantarflexion. Surgical indications include persistent pain or functional limitations refractory to conservative treatment. Contraindications include severe arthritis, poor vascular status, or a compromised soft tissue envelope.

Technique Description:

For AAI, the patient is slightly lateral with the thigh in a foam-lined leg holder. Minimal traction is applied through an ankle stirrup attached to a noninvasive sterile distractor. Standard anteromedial and anterolateral portals are created, with accessory portals made to access the submalleolar spaces. Impinging soft tissue and bony spurs are resected using a radiofrequency wand, shaver, and/or bur, followed by arthroscopic confirmation of resolution of impingement. For hindfoot endoscopy, the patient is prone with the involved ankle off the operative table end. Standard portals are posterolateral and posteromedial. The crural fascia is identified and released with a radiofrequency wand. The flexor hallucis longus is identified and is the most medial extent of any dissection to avoid neurovascular injury. Impinging structures are identified and resected using small joint instruments.

Results:

AAI arthroscopy has shown improvements in the American Orthopaedic Foot & Ankle Society (AOFAS) score, visual analog scale, Foot Functional Index, and dorsiflexion. The reported overall complication rate is 4%, with the most common being transient neurapraxia, superficial infection, and disturbed wound healing. PAI hindfoot endoscopy improves AOFAS scores and reduces time to return to play compared with open procedures. There is a reported 6% complication rate with transient sensory nerve symptoms, Achilles pain, and portal thickening being the most common.

Discussion/Conclusion:

Anterior and posterior ankle impingements are common in athletes and present with limited function, decreased range of motion, and localized pain. When conservative treatment fails, ankle arthroscopy and hindfoot endoscopy are effective surgical options that provide pain relief, modest improvement in range of motion, faster return to play, and low complication rates.

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

Background

In this presentation, we will discuss the diagnosis and management of anterior, posterior, and subfibular ankle impingement. Indications for surgery will be reviewed, and arthroscopic techniques will be demonstrated.

The source of ankle impingement stems from osseous and/or hypertrophic soft-tissue structures. In anterior ankle impingement (AAI), anterior tibial spurs impinge upon the talar neck during dorsiflexion. In posterior ankle impingement (PAI), an os trigonum is pinched between the posterior process of the calcaneus and the posterior tibia during plantarflexion. Subfibular impingement arises due to contact between the distal fibular tip and the lateral talar process. Combined impingement is less commonly observed.

Athletes with AAI, typically soccer players and runners, present with anterior ankle pain during terminal dorsiflexion. Activities such as climbing stairs, walking up hills, or deep squatting exacerbate pain. Frequently, patients note previous ankle injury^5,9 and experience motion loss and catching. Examinations reveal localized anterior ankle joint line tenderness,^5,9 which worsens with the hyperdorsiflexion test (Figure 1A). Those with PAI present with pain walking downhill, sprinting, and jumping. Ballet dancers who are en pointe are at risk due to repetitive supraphysiologic plantarflexion. ¹ Tenderness is elicited on palpation deep to the Achilles tendon on the posteromedial or posterolateral aspect of the ankle, with pain reproduced on the hyperplantarflexion test (Figure 1B).^6,7

Figure 1A.

Hyperdorsiflexion test. The examiner's thumb is placed over the anterior ankle joint, and the ankle is maximally dorsiflexed. Pain over the area of palpation is indicative of anterior ankle impingement.

Figure 1B.

Hyperplantarflexion test. The examiner's second or third finger is placed adjacent to the Achilles tendon over the posterior ankle capsule, and the ankle is maximally plantarflexed. Pain over the area of palpation is indicative of posterior ankle impingement.

Initial treatment includes activity modification, physical therapy, bracing, anti-inflammatory medication, and corticosteroid injections. Patients with refractory symptoms and functional limitations are indicated for surgery. ¹⁰ Contraindications include severe osteoarthritis, poor vascular status or soft tissue envelope, and previous infection.

CASE No.1

Indications

In our first case, a 44-year-old woman presented to our clinic after slipping on wet grass. Radiographs demonstrated an unstable Weber B ankle fracture. On further questioning, the patient endorsed dull aching in the anterior ankle for several months while running and climbing stairs. Radiographs demonstrated the Weber B fibula fracture as well as anterior tibial spurs, consistent with a concomitant diagnosis of AAI. The patient was indicated for ankle arthroscopy with spur debridement and open reduction and internal fixation of the ankle.

Technique Description

The patient is placed in a slight lateral decubitus position on a beanbag with a thigh tourniquet. The knee is flexed, and the thigh is placed into a padded leg holder. An ankle distractor is used with minimal traction. A standard anteromedial portal is marked just medial to the tibialis anterior. A spinal needle is directed perpendicular to the tibia at about a 45° angle from vertical. The ankle joint is deemed accessible. The skin is then nicked with an 11-blade, and a curved mosquito hemostat is used to spread the soft tissues. The 2.7-mm 30° arthroscope is inserted, and the pump pressure is set at 40 mmHg. The anterolateral portal is localized with a spinal needle placed just lateral to the peroneus tertius under direct scope visualization. The portal was created with the same nick and spread technique to avoid the superficial peroneal nerve.

Rupture of the anterior inferior tibiofibular ligament (AITFL) is seen due to an ankle fracture pattern. Debridement of the hypertrophic plica is performed around the anterior compartment, lateral gutter, and down the talar neck. Any talar neck spurs are removed. With the scope in the anterolateral portal, the medial gutter and anteromedial hypertrophic synovium are debrided using a shaver. The assistant can dorsiflex the ankle to help improve access to bur down the dorsomedial talar spur. Medial malleolar spurs were also excised. A full look at the completed medial resection is done.

Anterior tibial spurs are then removed with a bur and brought back to the level of the native joint line. The scope is switched back to the anteromedial portal to complete removal. The ankle is moved into maximum dorsiflexion to confirm that there is no impingement between the talar neck and the anterior tibia.

If needed, accessory portals are created to improve access to gutters and malleolar tips. Accessory medial and lateral portals are placed 1 cm inferior and 1 cm medial/lateral to their respective standard portal, or just distal to the anterior edge of the medial/lateral malleolus (Figure 2).

Figure 2.

Ankle arthroscopy accessory portals. The medial accessory (MA) portal can be made up to 1 cm distal and medial to the standard anteromedial portal. The lateral accessory (LA) portal can be made up to 1 cm distal and lateral to the standard anterolateral portal. These portals give access to the gutters and submalleolar spaces.

Incisions are closed, taking care not to entrap any superficial sensory nerve branches.

Results

Postoperatively, patients are immobilized in a short-leg splint for 3 to 5 days and then transitioned to a tall controlled ankle motion (CAM) boot. They are allowed to weightbear as tolerated. Early physical therapy is encouraged. Walsh et al ¹⁰ recommended starting cycling, stretching, and water-based rehab as soon as the portal sites are healed.

With respect to outcomes, a systematic review including 1506 patients showed improvements in the American Orthopaedic Foot & Ankle Society (AOFAS) score, the visual analog scale (VAS), and the Functional Foot Index scores. ⁴ Synovitis, osteophytes, meniscoid lesions, and AITFL injuries were present. ⁴

Walsh et al ¹⁰ reported on 46 patients with a minimum 5-year follow-up and found that weightbearing ankle dorsiflexion improved, along with Foot Function Index scores. Complications include transient neurapraxia (most common), permanent nerve injury, superficial and deep infection, wound healing issues, and reoperation. ⁴ Gianakos et al ⁴ reported an overall 4% complication rate and a 1% major complication rate.

CASE No. 2

Indications

Our second patient is a 16-year-old young woman presenting to our clinic with lateral and posterolateral ankle pain. She sprained her ankle previously and cannot participate in basketball. Examinations demonstrate normal standing alignment, anterolateral joint line, and distal fibular tenderness, and a positive hyperplantarflexion test. Radiographs show an os trigonum and a subfibular ossicle.

Magnetic resonance imaging reveals an os trigonum with surrounding soft-tissue edema and a large subfibular ossicle (shown with arrows). She failed a trial of bracing and physical therapy and was indicated for surgery. ⁷

Technique Description

For the hindfoot endoscopy set-up, demonstrated on a different patient for illustrative purposes, the patient is positioned prone with a tourniquet on the proximal thigh. The patient's ankle is placed several inches off the end of the table. Anatomic landmarks are marked, including a vertical line over the plantar first webspace, lateral malleolus, and medial malleolus, in addition to drawing a horizontal line from the distal tip of the fibula until it intersects with the lateral border of the Achilles. A spinal needle is placed just proximal to this intersection point and is directed toward the plantar first webspace to avoid posterior tibial neurovascular injury. The subtalar joint sulcus is felt with the tip, and the location of the posterolateral portal is confirmed. The nick-and-spread technique is used to create the portal. The 2.7-mm 30° arthroscope is introduced, with a pump pressure of 40 mmHg.

Using triangulation, a spinal needle is inserted in the posteromedial portal site transversely until it hits the arthroscope shaft. The needle is moved down the shaft until it reaches the tip of the scope, and is visualized. The portal is created.

Back to our Case

The flexor hallucis longus (FHL) (at probe tip) is identified after removal of the superficial crural fascia. Tendon excursion is confirmed with interphalangeal joint flexion. FHL designates the medial-most point of any work safely done. The mobile os trigonum is visualized.

The scope is advanced into the FHL tendon sheath, and by rotating the “eyes” of the camera, the tendon can be assessed for tendinopathy or tearing. Tracking of the tendon can be seen by moving the great toe.

The subtalar joint is then assessed. The talocalcaneal ligament is seen in the lateral gutter.

The soft tissue attachments to the os trigonum (posterior talofibular ligament, intermalleolar ligament extension, flexor retinaculum) are then methodically released with a radiofrequency wand or a shaver. The cleft where the os trigonum starts is identified, and the os is removed in a piecemeal fashion using a combination of shaver, bur, grasper, and/or hemostat. The remainder of the frayed soft tissue and cartilage is smoothed.

After removal of the os trigonum, the ankle joint can be accessed as needed. The arthroscope is advanced between the tibial slip and the intermalleolar ligament to evaluate the posterior ankle cartilage. Skin is closed with simple nonabsorbable sutures, taking care not to entrap any superficial sensory nerves.

The patient is repositioned, and ankle arthroscopy is then done through standard anterolateral and anteromedial portals. Hypertrophic synovial tissue is seen in the lateral gutter, and the subfibular ossicle is visualized. Using the accessory lateral portal for instruments while viewing from the anterolateral portal, the subfibular ossicle is then excised. A small area of soft- tissue attachment is kept until the ossicle can be easily removed with a grasper as a thin shell of bone.

Results

Postoperatively, there are no clear guidelines for when patients may begin weightbearing or range-of-motion exercises. Sugimoto et al ⁸ suggested immediate range of motion exercises with early weightbearing. At our institution, we use the same protocol as for AAI, with 3 to 5 days of splinting followed by weightbearing as tolerated in a CAM boot.

Sugimoto et al ⁸ evaluated 59 athletes with 72 procedures at a mean follow-up of 60 months. The mean AOFAS scores improved, and the mean time to resume training was 5 weeks postoperatively, while the mean time to return to competition was 13 weeks.

Gerogiannos and Bisbinas ³ compared open versus arthroscopic os trigonum excision in a randomized controlled trial, with 26 patients in each study arm and a minimum 5-year follow-up. Endoscopic excision resulted in greater improvement in AOFAS scores and faster return to play at 7 weeks.

Complications of hindfoot endoscopy include infection, neuritis, and heel cord tightness. One study followed 237 patients and reported an overall complication rate of 6.4%, most commonly transient superficial sensory nerve numbness.^2,8

Discussion/Conclusion

Anterior and posterior ankle impingements are common in athletes and present with limited function, decreased range of motion, and localized pain. When conservative treatment fails, ankle arthroscopy and hindfoot endoscopy are effective surgical options that provide pain relief, modest improvement in range of motion, a faster return to play, and low complication rates.