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23-03-2014 | Pain medicine | Article

Preoperative pain during knee range-of-motion predicts post-TKA pain


Free abstract

medwireNews: A simple test measuring pain intensity during active flexion and extensions before total knee arthroplasty (TKA) could identify which patients are likely to experience moderate to severe pain after the procedure, researchers report.

They found that patients who experienced severe pain, scoring it at more than 15 out of a possible 20, during this range-of-motion test prior to TKA were 10 times more likely to have moderate-to-severe pain 6 months after TKA than patients with mild or no pain.

Preoperative psychological distress also played a part, with a patient’s risk of postoperative pain increasing by 40% for every 5-point increase in anxiety levels on the State Trait Anxiety Inventory.

“If these findings are corroborated, this subset of patients considering TKA may need more thorough consulting and tailoring of expectations, as well as consideration of better preoperative interventions such as psychological counseling, medications or physical therapy to attempt to manage high pain levels with mild tasks such as simple un-weighted range-of-motion”, say the researchers.

Increased efforts to this effect “may ultimately increase the patient-reported satisfaction rates that both surgeons and patients would eagerly like to see improve as the cost-effectiveness of total knee surgery is further reassessed”, they add.

The study involved 215 patients, aged an average of 62 years. Before surgery, 52% had moderate-to-severe pain with the range-of-motion pain test and this fell to 16% at 6 months after TKA.

The researchers, led by Nicolas Noiseux (University of Iowa, Iowa City, USA), say that this level of ongoing pain is consistent with rates reported in previous studies.

To some extent, it can be associated with preoperative psychological factors including anxiety, depression or pain catastrophizing, says the team. Indeed, these were predictive factors in univariate analysis along with severe pain during active knee range-of-motion.

But in multivariate analysis only high anxiety levels and severe pain during active knee range-of-motion remained significant predictors of postoperative pain.

“Strategies to reduce these patients pain levels and psychological distress pre-operatively may improve outcomes in total knee replacement,” Noiseux et al conclude in The Journal of Arthroplasty.

medwireNews ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2014

By Lucy Piper, Senior medwireNews Reporter