YEARS AGO, WE EMBARKED on what seemed at the time a good idea for post-operative pain control. We sent patients home with pain pumps that directed anesthetic into the surgical joint space. The continuous local infusion of bupivacaine with epinephrine helped keep our shoulder surgery patients comfortable after what would otherwise have been very painful arthroscopic procedures.
But then we began noticing that, months into a normal post-op course, some of our patients began developing postarthroscopic glenohumeral chondrolysis, or PAGCL. An analysis revealed that all these patients had received intraarticular infusions post-op.
As we probed more deeply, we discovered that we had seen 12 cases of PAGCL over a 19-month period, in patients as young as 16 years old. All of these patients had undergone stabilization (e.g., capsular shifts, Bankart repairs), and all received pre- and post-op injections as well as post-op intra-articular pain pumps containing 250 mL of 0.25% bupivacaine HCL with epinephrine. Ten of these patients had to have subsequent surgery - including three excised humeral heads - and pathology revealed cystic changes with giant cells, lymphocytes and eosinophils, with no necrotic bone. Conversely, 104 patients with extraarticular infusions (superficial to the rotator cuff tendons) did not develop PAGCL.
Animal research published recently suggests the etiology of the problem:
It shows that bupivacaine and lidocaine with or without epinephrine can be cytotoxic to articular cartilage. It's possible that the shoulder may be particularly susceptible to the cytotoxic effects of these anesthetics. The shoulder joint space is relatively small, so intraarticular infusions result in a relatively high concentration of anesthetic inside the joint space.
The consequences of PAGCL are severe. Most patients had to consider some type of glenohumeral arthroplasty, even though the average patient in the group was only 29 years old. But there is some good news. The experience led us to an entirely new and better approach to pain control. We discontinued all continuous intra-articular infusions (not just shoulders), and we now routinely use interscalene peripheral nerve blocks (PNBs) for shoulder surgeries.
In the hands of an experienced anesthesiologist, PNBs provide much better pain control without significant complications, likely because they directly target the affected nerves. In fact, much to the surprise of everyone on our surgical team, many patients report greater than one pain-free day after a singleshot interscalene block. They rarely need opioids until the block wears off, and overall, I'm seeing a much lower use of narcotics than I did with local infusions.
For obvious reasons, I no longer recommend intra-articular infusions to my patients or my colleagues. But I do recommend PNBs to both. They are not only a safer means of pain control, but a more effective one.
Dr. Hansen is an orthopedic surgeon at Advanced Joint Care & Orthopedic Sports Medicine in Glendale, Arizona.