Change of Cognitive Performance Through Hip Replacement

The purpose of this study is to investigate the effectiveness of a hip arthroplasty for chronic pain, caused by a unilateral primary Coxartrhrose, regarding the cognitive performance. It is based on the hypothesis that the combination of chronic pain along with relative immobilization causes impairment of cognitive performance. The total hip replacement reduces pain, increases the mobility level and finally improves the cognitive performance.

Studies have shown that cognitive performance, especially in the elderly is limited due to chronic pain. In a recent study, significantly less brain activity in various regions of the brain (the anterior cingulate cortex (ACC), insula and operculum, dorsolateral prefrontal cortex and orbitofrontal cortex) was detected in patients with unilateral primary coxarthrosis compared to a healthy control group. After eliminating the pain by the implantation of a total hip replacement, a significant increase in brain activity in the affected areas was observed in these patients. Whether this observation is accompanied by an effect on cognition, is not known and will be investigated in the proposed study. The purpose of this study is to investigate the effectiveness of a hip arthroplasty for chronic pain, caused by a unilateral primary Coxartrhrose, regarding the cognitive performance. It is based on the hypothesis that the combination of chronic pain along with relative immobilization causes impairment of cognitive performance. The total hip replacement reduces pain, increases the mobility level and finally improves the cognitive performance.

The main issue concerns the short and mid-term influence of hip replacement on cognitive performance in the perioperative care continuum in comparison to a control group that does not have chronic pain. To objectively quantify the everyday activity, there are a variety of instruments, without a currently gold standard. Therefore, in addition the investigators use objectified measurement parameters with the aid of a pedometer (GARMIN vivofit) on every three measuring time points (before surgery, 3 months after surgery, 6 months after surgery).

Standardized neuropsychological assessment methods are used to assess the cognitive performance. To assess the degree of mobility, health status and the physical activity standardized questionnaires are used.

Primary hypothesis: After implantation of an artificial hip replacement and reduction of experienced pain patients with primary coxarthrosis indicate an improvement of cognitive performance 3 and 6 month after surgery compared to the pre-surgical status. In addition, the investigators measure how severe the cognitive performance is reduced compared to a healthy control group prior to surgery and to what extend the cognitive performance is reversible in the aftermath.

Eligibility Criteria:
Inclusion Criteria:

* primary, unilateral coxarthrosis
* planning for hip replacement surgery in Bad Bramstedt

Exclusion Criteria:

* dementia / cognitive impairment (Mini Mental Status Test \<25)
* chronic pain otherwise genesis
* reduced physical activity otherwise genesis
* lack of German language skills
* uncorrected serious impairment of vision or hearing
* serious additional psychiatric diagnoses (e.g. substance abuse / addiction)