Complex Regional Pain Syndrome or CRPS is a somewhat poorly understood but accepted pain syndrome marked by injury or surgery to a limb and the development of a constellation of symptoms (Laplant 2014).
When we are injured we experience what is known as a “fight or flight response” mediated by this sympathetic nervous system, and which is normally helpful in dealing with the injury, but in CRPS the reflex goes somehow wrong.
And your body responds in kind with pain and swelling and all of the other symptoms of 'fight or flight' like vasodilation or vasoconstriction (opening or closing of the blood vessels) that are responsible for the color changes of the skin in CRPS. It is like a computer that needs to be “rebooted”. This altered feedback loop is responsible for many of the symptoms of CRPS.
Types of CRPS
But, what can be done? Adequate pain relief to permit continued physiotherapy is imperative, most all agree. Not to be over-estimated, a diligent search by your surgeon for any other explanation of your symptoms that may be attributable to another cause. The mainstay of treatment has been continued physiotherapy, adequate pain management with opiate pain medication, NSAIDS (non-steroidal anti-inflammatories) as well as topical Capsaicin and Lidocaine patches, gabapentin and even anti-depressant medications and psychotherapy.
The management of continued pain after a knee surgery is not well established. Some surgeons, such as Toms, 2009 who studied TKA patients used a guidepost of increasing pain at the three-month mark, especially causing stiffness, to consider CRPS. He comments that revision procedures are rarely helpful in the treatment of CRPS. Many argue that revision surgery after a diagnosis of CRPS may only worsen the situation. There are situations when revision surgery is deemed necessary. Some teams perform revision surgery in which an anesthesiologist provides a nerve block pre-operatively, at the Lumbar-Sacral region (L5-S1). Before surgery, the nerves are “turned off” thereby allowing the body a form of 'amnesia for the insult', as it were, providing a greater chance that the body will fail to 'remember' the insult of revision surgery. These cases are largely anecdotal, and must be well timed and coordinated by a specialized team with the expertise to attempt these cases (Tubic, 2015).
CRPS is a diagnosis of exclusion, meaning that all other potential causes of the symptoms must be excluded. An informed and astute patient and physician and physiotherapist are imperative to making the correct diagnosis. Any disease, such as a postoperative infection that may be masquerading as CRPS, and is readily treatable, must be afforded the opportunity for appropriate treatment. CRPS is a clinical diagnosis, and there are no definitive tests that will declare the diagnosis. This too often this leads to a delay in diagnosis. As mentioned, CRPS is delineated to types I and II - however in this following discussion we will assume for simplicity purposes that we are discussing Type I.
CRPS is most common after hand surgery and in the upper extremity (Sebastin, 2011) however each year a percentage of knee patients will develop the disease postoperatively. Among all CRPS patients, randomized studies are few, especially among knee patients. However, reported CRPS after Total Knee Arthroplasty (TKA) is reported to be 21% at one year (Toms, 2009) with decreasing percentages at years 2 and three postoperatively. Among ACL reconstruction patients, the numbers appear to be lower, in the range of 4% (Reuben, 2004) however some estimates range that up to 13 % of patients who undergo this procedure will develop CRPS.
How to know if you are one of these unfortunate patients? As a patient, you may experience pain that appears disproportionate to what 'was expected'. This, as you may realize, is very subjective. Who knows what to expect? This may present as pain that is worsening as you get further out into 'recovery', not improving. Is your pain threshold stifling your physical therapy? If you notice any change in color of the affected limb, such as the limb appearing pale or a mottled purple, or if there is any sweating you must report this immediately. Swelling that persists is also of concern. Stiffness or atrophy of the limb is a late finding.
Jacquelyn Laplant, Robert Knobbler Early recognition of CRPS to facilitate effective early treatment. Neurology May 2014, poster
Sebastin, Sandeep Complex Regional Pain Syndrome. Indian Journal of Plastic Surgery 2011 May-Aug 44 (2) 29-307
Reuben, Scott. Preventing the development of Complex Regional Pain Syndrome after Surgery Anesthesiology 2004; 101: 1215-1224.
Fishman Scott, Ballantyne Jane et al. Bonica’s Pain Management. Wolters Kluver Health, 2012, pages 81-85.
Wilson, JG, MG Serpell. Complex Regional Pain Syndrome. Continuing Education of Anesthesia and Critical Care and Pain Management 2007 7 (2) pages 51-54.