Clinically, one of the most persistent, post-surgical pains that I see in my practice is that after a total knee arthroplasty (TKA). Surgically, the objective of the physician is to replace a patient’s mal-aligned, osteoarthritic knee which in turn should decrease pain and increase function. But despite objective measures of success, it has been reported that 15-30% of individuals who have undergone a TKA develop significant postsurgical pain and disability.
Several articles published over the past few months have examined why some individuals develop chronic pain following total knee replacements. A commonality between these studies seems to be pain catastrophizing (PC). PC is defined as, “an exaggerated negative mental set brought to bear during an actual or anticipated painful experience”. It is believed that reducing PC may be the key to improving post-surgical pain outcomes.
An article published in June’s edition of the Archives of Physical Medicine and Rehabilitation, assessed the effects of behavioral interventions pre-surgically for individuals (who were scheduled for a TKA) with elevated levels of PC. The examiners in this study provided a subgroup of patients with pain coping skills pre-surgically and compared their outcomes to patients who received the usual care. The pain coping skills were based off of Melzack and Wall’s gate control model of pain in which the experience of pain is influenced by thoughts, feeling and behaviors. The skills included relaxation training, pleasant imagery, activity-rest cycling/pacing, cognitive-restructuring and written maintenance plans. The results demonstrated that patients who received pain coping skills training reported significantly greater reductions in pain and PC, and improved functional outcomes as compared to their usual care counterparts.
If the results of that article aren’t convincing enough, another study, which is currently in press for publication in Pain, examined the role of pre-surgical expectancies in the prediction of pain and function one-year following a TKA. This study consisted of 120 individuals and looked at several measures pre-surgically and reexamined them one-year post-surgically. The examiners looked at pain, function, co-morbidities, pain catastrophizing, pain-related fear of movement, depressive symptoms and expectancies. The results, like the other article, demonstrated that psychological factors have a significant prognostic value in predicting prolonged pain and disability. Again, the pre-surgical pain catastrophizing predicted poorer recovery from a TKA.
From the results of the above two articles, I recommend that all patients complete the pain catastrophizing scale prior to surgery. It can be easily administered and consists of 13-questions which rate different thoughts and feelings that individuals may have when they experience pain. It has high internal consistency and has been shown to be associated with heightened pain and disability in patients with osteoarthritis. Based on the results, it is recommended that patients with high amounts of PC undergo pain coping skills prior to surgery. By decreasing PC, outcomes may ultimately be improved and there will be a lower likelihood for the onset of chronic post surgical pain.
Pain Coping Mechanisms
As an addendum to this article, I wanted to provide some strategies to help decrease PC in those with high scores on the Pain Catastrophizing Scale.
- Relaxation Training: Have your patient concentrate on muscle tension signals and use these signals as cues to relax. You can even have the patient create a muscular contraction for a short period of time but then focus on complete relaxation of that muscle. Continue to promote this relaxation until pain is reduced.
- Relaxation Breathing: Have your patient close their eyes, take a deep breathe in through their nose and blow softly out their mouth. Repeat until the patient feels relaxed.
- Pleasant Imagery: Make your patient note cards with pleasant images on them, and have your patient change from one image to another.
- Activity-rest cycling: Identify tasks in which the patient over-exerts themselves and have them break up the tasks into components of exertion and rest. Over time gradually increase the exertion portions of the task until they can complete them painfree.
- Maintenance plan: Have your patient keep a list of coping skills they learned and think about how they may apply them in the future.
Khan RS, Ahmed K, Blakeway E, et al. Catastrophizing: a predictive factor for postoperative pain. The Am J Surg 2011; 201: 122-131.
Riddle DL, Keefe FJ, Nay WT, et al. Pain coping skills training for patients with elevated pain catastrophizing who are scheduled for knee arthroplasty: a quasi-experimental study. Arch Phys Med Rehabil 2011; 92: 859-865.
Sullivan M, Tanzer M, Reardon G, et al. The role of presurgical expectancies in predicting pain and function one year following total knee arthroplasty. Pain 2011. Doi:10.1016/j.pain.2011.06.014.