Peri-surgical observation of nociceptive thresholds during total knee arthroplasty for association with persisting post-surgical pain: an explorative study

Total knee arthroplasty (TKA) often produce severe persistent post-surgical
pain (PPSP), and in some cases, chronic pain. While the acute pain postpones
the early recovery, the chronic pain seriously restricts an individual*s
quality of life, and also increases costs of global health care and absenteeism
at work. Central sensitization plays a major role in the development of PPSP.
Sensitization is characterized by generalized hyperalgesia and can be detected
by means of a decrease in (electrical) pain threshold. Recently, a pilot study
showed that pre-surgical electrical pain tolerance thresholds (ePTT) have
predictive value for PPSP in abdominal surgery patients. Other pilot studies
suggest that, in addition to ePTTs, electrical nociceptive perception
thresholds (eNPTs), when tracked over a short period of time (e.g. 25 minutes)
can be expected to be able to observe changes in peripheral and/or central
mechanisms in more detail than regular EPTs. Results after TKA show similar
persisting pain incidences as after abdominal surgery. Therefore, these
patients are a suitable population to study the generalizability of the results
found in previous studies.

The main objective of this study is to investigate the predictability of
persisting post-surgical pain (PPSP) after TKA using electrical quantitative
sensory testing (eQST) and nociceptive perception thresholds (NPT) in
combination with a pre-surgical conditioning pain modulation (CPM) paradigm.
The secondary objectives of this study are to investigate (1) the effect of TKA
on stimulus specific changes in NPT, and (2) the correlation between eQST
versus NPT and PPSP.

Mono-centre prospective observational study

This is a prospective exploratory study without experimental intervention.
After signing the informed consent form, patients will have four visits at the
Radboud University Nijmegen Medical Centre. The medical centre visits are
planned on days where patients are already scheduled for a regular visit. Pain
thresholds, pain tolerance thresholds, and nociceptive perception thresholds
will be measured using eQST and NPT equipment, and several questionnaires will
be filled in by all patients. All patients will undergo a cold pressor test
during the baseline measurement as well. Moreover, patients will also receive
two telephone calls including the relevant questionnaires. The participating
patients will obtain no direct personal benefit.