Magnesium Sulfate and Bupivacaine for Rehabilitation After Distal Radius Fractures

The fractures of distal radius are one of the injuries more frequents in orthopedics. Represent between 8-15% of all bone injuries in adults, and account for up to 20% of all fractures seen in emergency departments.

Despite the frequency of fractures of the distal radius, there is controversy about what is the best way to treat them. The principles of good treatment involving an anatomical reduction with a proper immobilization that keep the reduction. However, the immobilization must be for a brief period to achieve good functional results with a proper rehabilitation, allowing the patient to regain their independence and return to their occupational and daily activities.

One of the treatment employed in the fractures of distal radius is percutaneous pinning and use of rigid immobilization with a plaster for six weeks. Posteriorly we removed the immobilization and percutaneous pins. One of the aspects to take into account is that this procedure is ambulatory and pain in the wrist is an important factor that prevents him from performing a movement joint free, also generating dissatisfaction in the patient.

Recent research has shown that magnesium sulfate reduces postoperative pain applied during the surgical procedure. In addition, it reduces the consumption of opioids and presents no clinical toxicity, for these reasons magnesium sulfate can be considered as an effective adjunct to analgesia postoperative.

The investigators will realize a controlled clinical trial double blind with specific population characteristics, reproducible, prospective, comparative and longitudinal. This study is proposed to study 40 patients, randomly divided into two groups.

Intraarticular infiltration Prior to a detailed explanation of the protocol with signing of the informed consent, be performed intraarticular infiltration with magnesium sulfate alone or in combination with bupivacaine according to the randomization made. The patient will not know the group in which it is assigned, only the doctor who prepare the solution to infiltrate. This procedure will take place after the removal of the immobilization and fixation (plaster and pinning).

With the patient sitting, we realize asepxia with AVAGARD ® for 2 minutes., after this we proceed to intra-articular infiltration of the wrist with sterile technique, will be located by palpation the articular space between structures of the radiocarpal joint. One investigator will infiltrate 1ml of 10% magnesium sulfate with 1.5 ml of sterile water for one group and for the second group will put 1 ml of 10% magnesium sulfate plus 1.5 ml of Bupivacaine 5mg/ml. Posteriorly, another evaluator will perform measurements of range of active motion (ROM) with flexion-extension, radial and ulnar deviation, pronation and supination , as well as grip strength with a hydraulic hand dynamometer (JAMAR ®) and with the visual analog scale (VAS) to assess the pain.

The above mentioned tests shall be the minute one and three after intraarticular infiltration. Then apply PRWE (Patient Rated Wrist Evaluation) and DASH (Disabilities of the Arm, Hand and Shoulder) scales., this scales will apply to two and fourth weeks.

In the sample size calculation, was determined to include 20 patients per group, using a formula of mean differences with a standard deviation of 5 and an expected magnitude of the differences of at least 5 points in the PRWE scale, with a confidence interval of 95, power 80, with a p ˂0. 05 statistically significant β adding the error 20.

Inclusion criteria

• distal radius fracture treated with percutaneous pinning and plaster
• treated in our institution

Exclusion criteria

• allergy to drugs used
• drug use or abuse
• psychiatric disease
• pulmonal, cardiac, pancreatic, renal or hepatic disease
• active infection