Various sports medicine conditions are amenable to ankle nano arthroscopy
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The nano or needle arthroscopy system that was released for clinical use in September 2019 in the United States is a 1.9-mm arthroscope that can visualize into the ankle joint and be used to perform procedures while the patient is under a local anesthetic in an office or bedside setting. This technique is associated with little down time following the procedure compared to traditional arthroscopy or mini-open procedures.
The chip-on-tip camera optics of the NanoScope visualization system (Arthrex) provide 400 x 400 resolution with a 120° field of view and offer options for image and video capture. This system allows excellent visualization while instruments that are less than 2-mm in diameter can be used to resect soft tissue and bone. This nano technology system provides the orthopedic surgeon with a new image-guided alternative to primary or second-look arthroscopy. It has several potential applications in sports medicine (see Figure 1).
Ankle anteromedial impingement
Anteromedial impingement (AMI) in the ankle joint is a common cause of symptoms in soccer players, runners and dancers, and occurs due to repetitive microtrauma to the AM aspect of the joint. The treatment has traditionally been arthroscopic or mini-open bone and/or soft tissue resection with return to function at 2 to 3 weeks post-procedure. With the introduction of nano arthroscopy, the surgical arthrotomy portal is less than 22 mm in size. In the authors’ opinion, this results in early motion and return to sport that occurs more rapidly than when larger, traditional arthroscopes are used. AMI is just one application of nano technology among a myriad of sports-related foot and ankle procedures now amenable to this approach (see Table).
Nano arthroscopy for ankle AMI
After the patient has signed a consent and once the joint and procedure are confirmed, a local anesthetic of 4 mL of 1:1 ratio of lidocaine 1% and bupivacaine 0.5% is injected into the AM and anterolateral (AL) portal sites (see Figure 2). Then, 1 mL of the anesthetic is injected in and around the portal site. The rest of the anesthetic is injected into the joint, at which time the patient is commenced on 500 mg cephalexin taken orally and brought to the treatment room.
Using a sterile technique, the patient’s extremity is prepped and draped in typical sterile fashion. The patient lies or sits on the bench with the operated ankle hanging over the edge of the bench, which allows gravity to open the joint space. The surgeon and assistant then don sterile masks, gloves and gowns. An additional 6 mL of 1:1 ratio lidocaine and bupivacaine is used to infiltrate the joint one more time and establish that the portals can adequately gain access to the joint.
The NanoScope video tablet, shaver equipment and pump system stack are situated on a movable cart. The pump system can accommodate a number of options for inflow, outflow and fluid pressure monitoring to help ensure optimum visibility and distension. The basic patient prep kit, which includes syringes, scalpels and needles, is placed on a Mayo stand. The nano arthroscopy system, its cord, shaver, the suction tubing and other instruments are also placed on the same Mayo stand (see Figure 3). Available instrumentation for the system includes punches, graspers, scissors, a retractable probe, shavers, burrs and resectors (Figure 4).
Using a #11 blade, a standard AM portal is made. Using a spread and advance technique, the capsule is then entered using a small mosquito clamp. Care is taken to avoid iatrogenic injury to the cartilage. Once the capsule has been entered, a blunt trocar and obturator are advanced into the joint. The trocar is removed and the nano arthroscopy device is advanced into the joint. Once the scope is positioned intra- articular, the pump is started at 20 mm Hg. Using a forward-looking lens, which is at 0°, allows 120° field of vision. It may take a few minutes for the surgeon to become familiar with this lens compared with the traditional 120° field of vision provided by a traditional scope, which is angled 30° from the direct view.
Once the scope has been advanced to the AL portal, a spinal needle is used to identify the best portal entry anterolaterally. The same spread and advance technique is used to gain access to the lateral aspect of the joint. A probe is then inserted and a formal evaluation of the joint is made. The tibial plafond and talar dome are evaluated for chondral injury. The anterior inferior tibiofibular ligament is evaluated for hypertrophy. The ankle joint can be dorsiflexed to identify both soft tissue and bony impingement.
Using a 2-mm shaver, soft tissue can be resected to bone so the ankle dorsiflexion prevents entrapment of dorsal soft tissue. A 3-mm shaver may be used if excessive soft tissue is present. A 3-mm jacketed burr can be used with suction to resect any tibial bone overhang back to the level of the medial malleolar anterior border (see Figure 5). Patients do not typically experience pain with this procedure due to the local anesthetic; they usually only feel a sensation of vibration. Attention is directed to the talar neck. Should exostoses exist that may cause impingement, these also are resected.
Once the ankle has been put through a range of dorsiflexion and plantar flexion and no soft tissue or bony impingement is noted, the suction is used to deliver any remaining fluid from the joint. Wound closure strips are used to close the portals. Sutures are not typically necessary. A dry, sterile dressing is applied that facilitates early ankle motion. The patient can then ambulate with a postoperative shoe. The patient is encouraged to perform ankle pumps and circumduction exercises for 5 minutes every hour for the first 24 hours postoperatively and may walk, as tolerated. Applying ice to the anterior ankle and foot elevation above the level of the heart is encouraged any time the patient is not ambulating for 24 to 36 hours. The patient is seen on post-treatment day 5, at which time formal physical therapy is commenced.
- For more information:
- John G. Kennedy, MD, MCh, MMSc, FFSEM, FRCS(Orth), and Yoshiharu Shimozono, MD, can be reached at NYU Langone Health, 171 Delancey St., 2nd Floor, New York, NY 10002. Kennedy’s email: john.kennedy@nyulangone.org. Shimozono’s email: yoshiharu.shimozono@nyulangone.org.
Disclosures: Kennedy reports he is a paid consultant for and receives research support from Isto Biologics. Shimozono reports no relevant financial disclosures.