Effect of intra- and postoperative strategy of pain management on functional outcome in patients subjected to knee arthroplasty.

Rationale:
A Clinical Pathway for patients subjected to knee arthroplasty has been introduced in the Academic Medical Center Amsterdam AMC. In a multidisciplinary group including every department contributing to the clinical pathways of these patients, all aspects of pre-, intra-, and postoperative care including facilities at home have been discussed. Regarding anesthesiologic care, one major point is the best possible postoperative pain management and the influence of postoperative pain on long-term functional outcome. This topic shall be addressed in the current study.


Objective:
The aim of this clinical study is to investigate whether a combination of sciatic nerve blockade (single shot or continuous blockade) with continuous regional blockade of the femoral nerve will improve short and long term functional outcome as well as patient satisfaction after total knee arthroplasty.


Study design:
Single center, prospective, randomized controlled study.


Study population:
Patients subjected to total knee arthroplasty, age older than 18 years, American Society of Anesthesiologists (ASA) classification I to III.


Intervention:
In patients subjected to total knee arthroplasty post-operative pain therapy will be provided by patient controlled analgesia via femoral nerve blockade with or without single shot or continuous sciatic nerve blockade.


Main study parameters/endpoints:
Primary endpoint:
Reaching of discharge criteria (90 degree flexion of the knee, no infection, pain on the visual analogue scale (VAS) lower than 4 (scale 0-10)

Secondary endpoints:

1. Functional results at discharge and after 3 months and one year after the operation;

2. Analgesic consumption: Use of morphine and tramadol, pain measured by VAS postoperatively on day 0, 1, 2 and 3 during rest and movement, respectively;

3. Postoperative nausea and vomiting (PONV, 0: absence, 1: mild, 2: severe);

4. Effect of removing catheters on functional aspects (loss of functional capacity after removing catheters);

5. Patient overall satisfaction (measured using the Oxford knee questionnaire, a score with good reliability, content validity and construct validity in patients subjected to TKA15;16)Patient satisfaction with regional blockade procedure (school marks);

6. Time necessary to place catheters;

7. Amperage of stimulation of motor response;

8. Onset of motor and sensory block.


Nature and extent of the burden and risks associated with participation, benefit and group relatedness:
Sciatic blockade, in particular its motor consequences, might obscure diagnosis of perioperative sciatic nerve injury due to surgical incidences during the operation. Sciatic nerve injury after TKA has an overall incidence of 0.2 to 2.4%. However, addition of sciatic nerve blockade might be more effective for pain relief after TKA compared to femoral blockade alone. No additional burden is expected as clinically used routine pain management strategies are compared with each other.

A combination of sciatic nerve blockade (single shot or continuous blockade) with continuous regional blockade of the femoral nerve will improve short and long term functional outcome as well as patient satisfaction after total knee arthroplasty.

1. During stay of hospital;

2. 3 months after operation;

3. 1 year after operation.

In patients subjected to total knee arthroplasty post-operative pain therapy will be provided by patient controlled analgesia via femoral nerve blockade with or without single shot or continuous sciatic nerve blockade.