The Ankle



The Ankle





INJECTIONS AND ASPIRATIONS


Intra-articular Ankle Injection and Aspiration: Antero-medial and Antero-lateral



Description of Procedure



  • Position the patient upright with the ankle dependent with gravity. The use of gravity helps manually distract the joint. If needed, an assistant can “pull” the ankle as well, but usually this is not needed.


  • Prepare a wide area of the skin with antibacterial solution.


  • The ankle and foot lend themselves to careful palpation, given theirs subcutaneous location.


  • The perfect spot for an ankle injection is just medial to the anterior tibialis tendon at the level of the joint line. The joint line can usually be palpated by running your thumb on the anterior aspect of the distal tibia until a soft spot is felt as the thumb enters into the joint line (Fig. 7-1).


  • An anterolateral injection can be used as well. It is slightly more difficult than the anteromedial injection but useful for cases with medial cellulitis or traumatic wounds. There is a soft spot just lateral to the EDL tendon that is the ideal spot for anterolateral injections. The main area of concern is the superficial peroneal nerve, which is to be avoided. (See section on ankle blocks.)


  • Optional: Anesthetize the skin overlying the planned entry site with 2 to 3 mL of local anesthetic. However, if an infection is being ruled out, do not use local anesthesia as lidocaine can act as a bacteriostatic agent and decrease the chance of a positive culture.


  • Direct the needle through the skin into the ankle joint. We typically use a 22G needle for injections. If bone is encountered, either raise or lower your hand as the needle is hitting either distal tibia or talus.


  • Aspirate synovial fluid to verify that the needle is appropriately positioned. If no fluid is withdrawn, attempt injecting minimally. Often, it is difficult to withdraw fluid from the ankle unless an effusion is present. If there is resistance, stop the injection and consider using a fluoroscopic image machine for assistance.


  • Continue aspirating or inject the desired solution.


  • Apply a sterile, compressive dressing.







FIGURE 7-1


Tips and Other Considerations



  • The use of local anesthetic is debatable. Some physicians feel it is not helpful because only the skin will be anesthetized and a second injection is required. In the pediatric setting, fewer injections are better.


  • Entry into the joint may be facilitated by plantarflexing and manually distracting the ankle by wrapping the posterior aspect of the ankle with your nondominant hand and pulling distally.


  • If fluid is not initially obtained, redirect the needle. The needle must be withdrawn until it is just within the skin before redirection. Changing the angle of the needle without withdrawing it first will simply push tissue around (not change its path) and may even risk damage to surrounding tissue, as the bevel may act like a knife.


  • A typical mistake is inserting the needle too proximal making it impossible to enter the joint.


  • When an intra-articular ankle injection is performed in the setting of a fracture, usually a large effusion is present and it is difficult to feel the joint line. In this setting, however, the use of local anesthesia can be very helpful in performing closed reductions of displaced or dislocated ankle fractures. Often, we use a large-bore needle (18G) to “find” the effusion and withdraw some of the blood and then switch syringes to fill the joint with local anesthetic. This procedure usually provides the patient a significant decrease in pain for the attempted closed reduction.



Regional Ankle Block



Description of Procedure



  • Position the patient in a supine position with the knee extended; external rotation at the hip will help gain access to the medial side of the ankle.


  • Prepare a wide area of the skin with antibacterial solution.


  • We prefer to inject the local solution with a 22G needle. An 18G needle seems to be too large and can cause too much damage, while a 25G needle can make the infusion of a large volume of fluid very difficult.


  • We typically use a mixture of 1% lidocaine and 0.5% Marcaine, both without epinephrine, mixed in a one to one ratio.


  • Depending on the area of the foot that the provider wishes to anesthetize, one or more of the following nerves may be anesthetized.



    • Tibial nerve for the plantar foot.


    • Superficial and deep peroneal nerves for the dorsum of the foot. The deep peroneal nerve supplies sensation to the first web space.


    • Saphenous nerve for the medial hindfoot and midfoot.


    • Sural nerve for the lateral foot.


Posterior Tibial Nerve Block

Mar 14, 2020 | Posted by in ORTHOPEDIC | Comments Off on The Ankle
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