A Pertinent Guide To Basic Ankle Arthroscopy
- Volume 16 - Issue 11 - November 2003
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When approaching the anterior aspect of the ankle, it is best to identify topical landmarks. Typical marking should identify the anterior tibial tendon, the extensor hallucis longus tendon and the anterior tibial artery. One should do this prior to joint distention since the areas marked may become distorted.
At this point, you would employ either a two- or three-portal approach. I choose to use an anteromedial and anterolateral approach. The anterocentral approach is an acceptable portal as well, but carries the added risk of being very close to the neurovascular bundle. Although you should be cautious with this approach, it is an excellent portal for viewing the ankle. 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.