Orthopaedic applications for the arthroscope continue to expand and, in the foot and ankle, to permit exploration in and around small joints. Arthroscopy of the first metatarsophalangeal (MTP) joint, peroneal tendoscopy, and endoscopic calcaneoplasty are among these new arthroscopic applications.

At the annual meeting of the American Orthopaedic Foot & Ankle Society, Eric Giza, MD, chief of the foot and ankle service at University of California–Davis, provided an overview of these techniques.

“In the last decade, the quality and the technology of small-joint arthroscopy has improved so much that we can put the scope into tendon sheaths and joints that we previously weren’t able to reach,” said Dr. Giza.

The smaller incisions afforded by arthroscopy result in less disruption of the natural anatomy and physiology, particularly in the tendon sheaths, Dr. Giza said, and patients can recover more quickly.

“Inflammation or synovitis may develop around peroneal tendons,” Dr. Giza noted. “Because the positive predictive value of MRI is only about 48 percent with peroneal tendons, an arthroscopic evaluation of the sheath may lead to a direct diagnosis and enable the surgeon to differentiate between a torn tendon and inflammation without creating too much of an exposure.”

In and about the hindfoot, the arthroscope has been useful and effective for treating Haglund’s deformity and the painful inflammation it causes about the Achilles tendon.

“Nerve irritation and tendon rupture are common complications of previous procedures,” said Dr. Giza. He noted that surgeons can easily remove bone in the back of the calcaneus to decrease boney irritation along the tendon sheath by using the arthroscope. This procedure is actually endoscopic rather than arthroscopic because it occurs in the back of the joint, rather than in the joint itself.

First MTP applications
In the first MTP joint, an injury may lead to painful catching and locking. Indications for arthroscopic exploration and repair include MTP or proximal phalanx osteochondral defects, synovitis, pigmented villonodular synovitis (PVNS), loose bodies, grade 0 or grade 1 hallux rigidus, and capsular scarring after turf toe.

“Patients can get scarring after subtle injury to the hallux,” said Dr. Giza. “Arthroscopy is a great way to be able to see all parts of the joint without disrupting the ligaments on either side of it.”

The equipment for working in this small joint includes a 1.9 mm scope, a “finger trap,” a weight of 10 to 15 pounds, small shavers, and microfracture awls.

“We borrow from our hand colleagues and use the ‘finger trap’ as a device to grab on to the great toe,” Dr. Giza explained. “General traction is used to distract the joint, and a small 1.9 mm scope is inserted through two incisions on the dorsal aspect of the great toe. That provides good access to the joint and enables the surgeon to see loose bodies, cartilage defects, joint inflammation, and scarring.”

The technique can be used to remove the dorsal osteophyte or bone spur that can occur with hallux rigidus or arthritis of the first toe joint. Typical patients are younger athletes with damage to the toe subsequent to a sports injury. For example, a patient with “sand toe”—a condition seen in beach volleyball players—could be treated arthroscopically. After arthroscopic synovectomy, loose body removal, and dorsal capsule reefing, a patient could return to competition in 6 months.

Peroneal tendoscopy
For the peroneal tendons, arthroscopic techniques can be used to assist in diagnosis of a patient with pain but no tear seen on MRI. Arthroscopes may be used for débridement in tears and synovitis and to address stenosis at the inferior retinaculum.

The set-up for peroneal tendoscopy involves lateral positioning with a bean bag holder; blankets are positioned under the medial malleolus to allow for inversion and eversion. The fibula, the fifth metatarsal base, peroneus brevis and longus, and the peroneal tubercle are used as landmarks. Three portals—superior, middle, and inferior—are used (Fig. 1).

“Three small incisions are made along the length of the tendon—one superior to the distal fibula, one just at the level of the fibula, and one more inferior down toward the cuboid,” Dr. Giza explained. “The scope is moved from each portal to examine the tendons and get good visualization. By using small shavers, the surgeon can débride the tendons and in some cases perform repairs of small tears through percutaneous suture techniques.”

Specifically, after the tendon sheath is injected with saline, the arthroscope is introduced from the middle portal looking superiorly (Fig. 2). The tendons are assessed, and then the scope is moved to the superior portal for examination of the tendons and fibular groove. Split tears and synovitis of the tendon may be identified and débrided (Fig. 3).

The arthroscope is moved to look distally for viewing of the fibrocartilaginous tunnel at the peroneal tubercle and the longus as it goes into the cuboid tunnel.

Typical patients are athletes or those who do physical labor.

Endoscopic calcaneoplasty
Endoscopic calcaneoplasty provides visualization of and access to the retrocalcaneal space, allowing for removal of an inflamed retrocalcaneal bursa as well as part of the calcaneus, as indicated for conditions such as a painful hindfoot.

For set-up, the patient positioning may be prone or supine. “I prefer the supine approach so that the tendon falls away from you,” Dr. Giza said. With the patient’s leg in a leg holder, he makes two small incisions just in front of the Achilles tendon, just below the level of the calcaneus. Using a small shaver and electrocautery, he can remove the retrocalcaneal bursa just in front of the Achilles tendon and gain excellent visualization of both the calcaneus and the Achilles tendon.

Dr. Giza performs a bursectomy first, with blades facing away from the tendon. Then, he uses a burr or rasp to remove the bone that is irritating the tendon.

Advantages of the technique’s minimized soft tissue disruption include faster healing leading to a quicker return to play. In one study, arthroscopic removal of the os trigonum to relieve impingement in 28 professional soccer players resulted in an average return to play of about 40 days, much more quickly than with open techniques, noted Dr. Giza.

Typical patients are younger and tend to have pathology that is not so severe that it interferes with their daily activities, Dr. Giza said. The procedure is probably not appropriate for patients with large insertional calcification and calcification within the tendon.

In addressing contraindications, Dr. Giza emphasized appropriate patient selection. “When you have a hammer, everything looks like a nail,” he cautioned. “Surgeons without much arthroscopy experience need to be careful not to overuse the techniques. As these techniques become more popular and residents get more training with them, their use will increase, but physicians should exercise good clinical decision making and make an open incision if needed.”

Dr. Giza advises becoming familiar with large-joint arthroscopy—knee and shoulder—before moving on to smaller-joint arthroscopy, such as the ankle and subtalar joint. “The learning curve is large. Of the techniques I have discussed, probably the most straightforward is the first MTP arthroscopy. The surgeon can visualize the gross anatomy while performing the procedure. This contrasts with endoscopic calcaneoplasty and the excision of the os trigonum, which have a higher degree of difficulty. For the os trigonum excision, the proximity of the neurovascular bundle means that the surgeon should be experienced.”

Dr. Giza uses a fluid such as lactated Ringer’s solution with a small amount of epinephrine to decrease bleeding and improve visualization. He also chills the fluid bags overnight, which helps restrict some of the extravasation into the tissues.

He noted other applications for small-joint arthroscopy, including tendoscopy of the posterior tibial tendon, endoscopic plantar fascia release, and endoscopic gastrocnemius recession.

“There is a big future for this type of minimally invasive approach,” he said.

Disclosure information: Dr. Giza—Arthrex, Zimmer.

Terry Stanton is a senior science writer for AAOS Now. He may be reached at tstanton@aaos.org

Bottom Line

• Current arthroscopic technology allows access to a number of small joint spaces and tendon and ligament sites, including the first MTP joint, peroneal tendons, and the Achilles/calcaneus region.
• Benefits include enhanced diagnostic capability and faster healing with fewer complications, due to reduced exposure.
• For pathology about the Achilles tendon, arthroscopy offers improved access for bursal excision and calcaneoplasty.
• Familiarity and competency in large-joint arthroscopy is a prerequisite for working in smaller anatomic spaces. Appropriate case selection criteria should be followed.