The experience of pain is common among hospital inpatients. Orthopaedic surgery often results in significant pain, which may last for some time. About one in eight people will experience long-term or chronic pain after surgery, which can impact on quality of life and mood. Some risk factors are known for chronic post surgical pain (CPSP) and these include patient factors, surgical factors and anaesthetic factors. We know that mood problems (anxiety and depression) increase the risk of CPSP. What is not known is how short term changes in mood are related to the experience of pain after surgery and how this impacts on CPSP. This study is designed to investigate the relationship between both short and long-term mood problems and short and long-term pain and quality of life after orthopaedic surgery. The study will provide valuable information to allow us to design a psychological intervention, which might reduce the risk of short-term post surgical pain and CPSP.

This study also aims to measure a number of other variables, which may be related to CPSP including medication use, other medically unexplained symptoms and catastrophic thinking in response to pain.

All patients having planned orthopaedic surgery will be asked to enter the trial. Those consenting to involvement will complete a questionnaire assessing the variables described above. They will be divided into two groups depending on whether they have significant pain on the day after their surgery. As the primary aim of the study, the rates of significant anxiety or depression will then be compared between these two groups.

Secondary outcomes will be assessed by a questionnaire sent to the patients at 6 months after their surgery. Descriptive statistics will be produced for all the variables and use to model a future study, which would assess the effect of a psychological intervention on acute and chronic post surgical pain.

Our hypothesis is that patients are more likely to experience acute anxiety and depression or display catastrophic thinking if they suffer significant post-surgical pain. The study is powered to reliably detect a three-fold difference in the prevalence of psychopathology between patients with and without acute pain on day 1 after elective orthopaedic surgery.

This is a prospective case-control observational study. The primary aim is to determine whether patients with poor pain control on day 1 following surgery have higher levels of anxiety / depression or catastrophising than those without acute pain. The cases are patients with significant pain on day one after surgery and the controls are sex, age and operation matched individuals without pain.

Several other variables are measured which may provide information for the design of future studies. The presence of pain or psychopathology prior to surgery will be recorded, as this is likely to impact on these variables in the post-operative period. Analgesic use pre and post surgery is also of interest as a surrogate measure of pain severity.

In addition to day one data, pain severity will also be recorded on day 2 and 3 post-operatively. This is of interest as although most patients will be expected to demonstrate reducing pain severity with time, a proportion will not improve and a small number will experience increasing pain with time. This adverse "pain trajectory" might be associated with an increased incidence of CPSP 28.

Long-term outcomes such as pain and quality of life at 6 months post-discharge will also be assessed by postal questionnaire.

The eventual aim of this series of studies is to assess the interaction between acute psychological problems and post-surgical pain and the impact that this has on longer-term outcomes such as CPSP, mood and quality of life. Short-term pre- and post-operative psychological interventions will then be developed to modify the impact of psychological factors on long-term surgical outcomes. Further studies will assess the efficacy of these interventions. Pre-study audit will be carried out to confirm the feasibility of matching.

Inclusion Criteria:

• All inpatients on Sharp, Shaugh or Stannon ward following elective orthopaedic surgery carried out on Monday to Thursday each week.

Exclusion Criteria:

• Patient refusal, Age <18, Emergency / trauma surgery, Day case surgery, unable to read or understand written instructions, No contact address, Not registered with a General Practitioner (GP)

The study population consists of all patients following elective orthopaedic surgery with a planned inpatient stay of at least 24 hours