Effect of NMBA on Surgical Conditions in THR
Effect of NMBA on Surgical Conditions in THR
During Total hip replacement arthroplasty (THA), the hip joint first must be luxated in order
 to have access to the joints. A lot of force and torque must be carried out on the joint to
 perform this manipulation. This is both difficult for the surgeon and may cause additional
 tissue damage and postoperative pain. After placement of the prosthesis and reduction of the
 joint, the tension of the hip joint must be evaluated by the surgeon to ascertain the
 adequacy of the prosthesis. During luxation, minimal muscle tension would be ideal, while
 after reduction of the joint, normal muscle tension is desired to permit assessment of the
 mechanics of the hip joint.

 The aim of the study is to investigate whether deep neuromuscular block, combined with a
 reversal before mechanics assessment improves surgical conditions, surgical time, and
 postoperative patient comfort.
2X20 patients are randomised: Rocuronium-group (R-group) and Placebo-group (P-group).

 All patients receive standardised multimodal intravenous analgesia. After standardised
 induction of anasthesia and patient positioning, the patient is administered either placebo
 or rocuronium 0.9 mg/kg, followed by continuous infusion of either placebo or rocuronium 0.4
 mg/kg/h. 1 minute before reduction of the hip joint, the patient is administered either
 sugammadex (R-group) or placebo (P-group) for full reversal of the neuromuscular block.

 During the surgery, time points are recorded for: incision, start luxation of the joint,
 start reduction of the joint, start skin closure.

 The surgeon is blinded for patient allocation. At three moments (after luxation, just before
 reduction of the joint, and after assessment of joint mechanics), the surgeon is asked to
 appraise the surgical conditions on an analogue scale.

 Postoperative analgesic consumption and pain scores are recorded. VAS scores for knee pain
 and hip pain are assessed before surgery, at the moment of discharge from the post-anesthesia
 care unit (=D0), the morning after surgery (=D1), at D2, and at D7.
Inclusion Criteria:

 -  signed informed consent

 -  eligible for primary THA

 -  BMI <35

 Exclusion Criteria:

 -  neurological or psychiatric disorders

 -  intolerance or allergy against investigational drugs or any of the drugs used in the
 standardized analgetics scheme (acetaminophen, diclofenac, ketamine, clonidine,
 lidocaine)