A Pertinent Guide To Basic Ankle Arthroscopy
When using the three portal approach, you may place the camera within the central incision. Typically, one does not have to remove it and place it in a different portal. Helpful Pointers For Minimizing Surgical Risks Some surgeons choose to distend the joint with a large syringe and saline or lactated Ringer’s solution. Distending the joint in this fashion serves to “inflate” the joint and ease the entrance of the equipment. Although the exact amount will vary in each patient, you will usually need 25 to 30 ml of fluid for distention. This may vary significantly if there is arthrosis or previous capsular damage. Although several types of pressurized inflow systems exist, many surgeons find saline or lactated Ringer’s solution and gravity flow are adequate to fully complete the procedure. If I do distend the joint prior to arthroscopy, I will place the skin incisions and bluntly dissect down to the joint capsule with a small pair of hemostats. At this point, I will introduce the syringe and fluid through the capsule. Again, this is a matter of preference. In many cases, I have found that the joint doesn’t have to be distended prior to the arthroscopy. Appropriate placement of the equipment and ensuring the inflow of fluid is adequate to distend the joint. Several surgeons make the incisions for the portals vertically. I choose to make them within the skin lines in a horizontal fashion. This seems to lessen the postoperative scarring, but does slightly increase the chances of venous and nerve injury. In positioning the anteromedial portal, you should make it medial to the anterior tibial tendon and lateral to the medial malleolus. The anterolateral portal is situated just lateral to the peroneus tertius tendon and medial to the lateral malleolus. In the medial portal, you should avoid the saphenous nerve and vein. In the lateral portal, avoid the intermediate dorsal cutaneous nerve, the perforating peroneal artery and the lesser saphenous vein. After using hemostats to bluntly dissect to the joint capsule, you can use the obturator (a rod with a blunt, cone-shaped tip) or trocar (a rod with a sharp tip) to pierce the capsule. Most surgeons suggest using the obturator to reduce the possibilities of iatrogenic cartilage damage. It is important to bear in mind that the obturator, although blunt, can still cause significant cartilage disruption. Proceed to remove the obturator or trocar from the canula. If you have distended the joint prior to entry, you may notice back flow of the saline or lactated Ringer’s solution. This tells you that you are within the joint capsule. Key Equipment Considerations For Obtaining The Best View The most common arthroscopes are 2.7 mm and 4.0 mm in diameter. Although the 2.7-mm size is more maneuverable within the ankle joint, one must exercise a considerable amount of caution in order to avoid damaging the scope. It is easy to concentrate solely on the viewing screen and not realize the camera is torqued. I use the 4-mm arthroscope for most ankle procedures unless there is significant joint damage and little joint space is available. There are several lenses that are angled to varying degrees. The angles create obliquity within the field of vision. Once a surgeon is experienced with arthroscopy, altering the obliquity to gain vision of different areas within the joint is extremely helpful. The most common angle to use on the 4-mm arthroscope is 30 degrees. Whether you place the camera within the medial or lateral portal will typically be dictated by the pathology you are treating. In general, placing the camera within the anteromedial portal will allow you to see the medial gutter, the anterior joint line and some portions of the lateral gutter. Placing the camera laterally will only emphasize the opposite structures. Other Essential Pearls To Keep In Mind It is important to remember that not all ankle joints will be easy to enter. In certain instances, debridement of hypertrophic synovium or adhesed capsule may be necessary to adequately maneuver within the joint. A common surgical error is not fully entering the ankle joint and assuming that hypertrophic tissue is obscuring the view. This leads to debridement of healthy capsule and allows fluid within the joint to spread into the subcutaneous tissues. Once you are inside the joint, you should first orient yourself and then routinely check for synovitis, instability and cartilage derangement.