Local infiltration with anesthetics vs placebo in patients with elective total hip replacement (thr) in fast-track protocol

Approximately 23,000 hip prostheses are placed annualy in the Netherlands in
patients suffering from symptomatic coxarthrosis. The purpose of this operation
is to improve the quality of life by releaving joint related hip pain and
increasing mobility. Early mobilization of patients after surgery is important
to prevent complications such as a urinary tract infection, pneumonia, deep
vein thrombosis and pressure ulcers. The multidisciplinary multimodal
Fast-Track protocol is based on the fact that people who fast mobile are less
likely to develope these complications. Because post operative pain interferes
with an early mobilisation, local infiltration anesthesia per-operatively (LIA)
is an important part of the Fast track protocol. This aims to reduce the pain
around the operation area. When placing total knee prostheses administering LIA
is proven effective, however the utility is as yet not yet shown when placing a
THP. Some studies describe reduction of pain and a shortened hospital stay
after administering LIA in the wound edges of the surgical area, but these
results could not be repeated in another study.

Administering LIA surrounding the nerves in the surgery area has not been
investigated previously. Cutaneus femoralis lateralis and the facial nerve
nervus subcostalis innervate the skin at the level of the hip.Theoretically
infiltrating the subcutaneous area of this nerve sprigs around the spina ilica
superior anterior results in conduction anesthesia of skin at the location of
the surgical area. The purpose of the present study is to show that local
infiltration anesthesia with ropivacaine in patients with THP in the fast-track
protocol leads to better pain reduction than placebo 24 hours after surgery.

Primary objective:
The primary purpose of the research is to determine the difference in pain
experience during rest, measured by means of an 11-point Numerical Rating Scale
(NRS), between peroperatieve Local infiltration with Analgesics (LIA) vs.
placebo, 24 hours postoperatively in patients with total hip replacement in the
fast-track protocol.

Secondary objective: a secondary objective of the study is to determine the
difference in secondary outcome measures between peroperatieve Local
infiltration with Analgesics (LIA) vs. placebo, postoperatively in patients
with total hip replacement in the fast-track protocol.

The secondary outcomes are:
-HOOS (pre OK and 6 WKS post)
-SF12 (Pre OK and 6 WKS post)
-Oxford Hip score (BL and 6 WKS post)
-Length of stay
-Presence of nausea, vomiting, bladder retention
-Complications
-Use analgesics: PCA-use/opiates
- NRS for pain during rest and mobilization till 48 hours postoperatively

This study concerns a single-center, placebo-controlled, double-blind
randomized study to investigate the postoperative pain in patients with total
hip replacement (thr) in a fast-track protocol.
Clinic: Department of Orthopaedics in the Spaarne Ziekenhuis

In our study, the post-operative pain in patients who have undergone a THP
examined. The subjects are divided into two groups.
Patients in Group 1 get an infiltration with ropivacaine pre-operatively 3.75
mg/kg (0.5 ml/kg body weight).
Patients in Group 2 get a pre-operatively infiltration with NaCl 0.9% (0.5
ml/kg body weight)

Ropivacaine is an anesthetic which is used for local anesthesia. The
administration takes place via the cutaneus femoralis lateralis and the facial
nerve nervus subcostalis . The maximum cumulative 24-hour dosage, which is well
tolerated is 675 mg (source: ChemSpider). In our protocol patients get 3.75
mg/kg, which is well below this dose ropivacine. Side effects are rare and
usually the result of overdose mistakenly given by intravascular injections
(hypotension, nausea > 10%; headache, paresthesia, dizziness, bradycardia,
tachycardia, hypertension, vomiting, urinary retention, temperature rise,
muscle stiffness, backache > 1%). To prevent this is before infiltration first
the needle is aspirated in order to exclude intravascular placement.
Subcutaneous administration of NaCl does not bring any increased risk to the
patient.


The parameters that are evaluated are not a burden for the patients because
these data is structural collected in all patients. No additional
investigations and/or actions will take place