Pertinent Insights On Arthroscopic Ankle Synovectomy And OCD Drilling
Ankle arthroscopy is a valuable minimally invasive modality to perform diagnosis and therapeutic treatment to the ankle joint. Acute and chronic ankle injuries can lead to synovitis and cartilage defects requiring surgical treatment. There are some general approaches that can be useful to the surgeon who has not become completely comfortable maximizing his or her arthroscopy skills.
For the majority of indications, I utilize a 30°, 4.0 mm arthroscope. When performing a synovectomy, I prefer a 3.5 mm aggressive oscillating shaver set at 3,000 rpm. It is necessary to have curettes, graspers and awls on hand to treat both known and unanticipated defects and loose bodies.
I place the majority of ankle scope cases in a non-invasive distractor. This serves to allow deeper joint penetration of the instrumentation but unfortunately also limits ankle maneuverability. The cartilage surface is also in a more vulnerable state due to the exposed anterior talus while the foot is held in a plantarflexed position. Eliminating the distractor allows the surgeon to dorsiflex the ankle using one’s midsection, thus protecting the cartilage during instrument insertion. However, surgical awareness and blunt instrumentation limits this iatrogenic cartilage risk when one utilizes a distractor.
Prior to placing the leg in support, I mark the superficial peroneal course, the tibialis anterior tendon and the level of the joint. If the superficial peroneal nerve is not evident, I await transillumination to choose the lateral port location. One places the anteromedial incision directly medial to the tibialis anterior tendon. The antero-lateral incision can be medial or lateral to the superficial peroneal nerve but always lateral to the common extensor tendon. I place the thigh in a support and pad the prominences well. Typically, I avoid putting up the tourniquet initially as it is often not required due to traction exsanguination and lidocaine with epinephrine joint insufflation.
I utilize a cannulated spinal needle to insufflate the joint from the anterior medial aspect. I insert the spinal needle, attach the syringe and inject 10-15 mL lidocaine with epinephrine, making sure to aspirate initially to verify joint entrance. This serves to limit intracapsular bleeding and provide an enlarged target for equipment entrance. The spinal needle gives one confidence the incision will be in the ideal location.
One tip to remember is that if there is anterior lipping of the tibia, it is best to start a few millimeters distal to the joint line and aim slightly superior to gain access. I prefer a #15 blade to make a 1 cm vertical incision and a curved hemostat to dissect down to the capsule, spreading often to protect any nearby structures.
I imagine the anterior ankle as an oblong bubble or sausage shape, and insert equipment to stay superficial to the intra-articular space until direct visualization allows for safe maneuvering. I introduce a blunt obturator and dual portal cannula. The talus, tibia and capsule/synovitis should be visible. I transilluminate a safe zone laterally, taking note of the marked nerve. I again enter with the spinal needle and visualize its entrance on screen. This allows one to adjust lateral incisional placement prior to actual incision. Once you confirm this, make the 1 cm incision with a #15 blade and deepen it to the capsule with a hemostat. Introduce the blunt obturator within the capsule and follow this with the instrument of your choice. If there is overwhelming synovitis, you will need a shaver to improve visualization and create a working space. Use a probe to palpate the cartilage surface while scanning with the scope, examining for defects.
Perform any debridement, curettage, drilling, that you can perform while the scope is medial. Then place the scope in the anterior lateral portal to allow access to the entire anterior joint. Take pictures to demonstrate the pathology, both to facilitate patient understanding of pathology and to allow one to revisit the joint appearance prior to repeating surgical intervention in the future if necessary.
Finally, I attempt closure with care to avoid enveloping the associated superficial neurovascular structures. I apply a compressive dressing with posterior dressing prior to leaving the OR. If one uses a tourniquet during the case, letting the tourniquet down to ensure bleeding from microfracture sites is beneficial to verify successful technique.
Ankle scoping can be enjoyable and I have learned to expect solid outcomes. These techniques have served me well for reproducible, routine arthroscopy for synovitis with and without microfracture.