Page 85 - Journal of Special Operations Medicine - Summer 2014

relief in patients with advanced age or comorbidities poster in the ED recruited patients. These clinicians first
that can lead to kidney impairment with the use of non- recognized patients with inclusion criteria after using
steroidal anti-inflammatory agents on kidneys. 8 the history, physical examination and associated stud-
ies to determine if they met any exclusion criteria. The
In contrast to the multiple studies of intra-articular mor- inclusion criteria for participation were patellar dislo-
phine in the surgical and chronic pain settings, there are cation, acute or acute on chronic meniscal tears, and
no studies of its use in the ED or deployed setting for anterior cruciate ligament (ACL), posterior cruciate lig-
acute knee pain due to injury. We sought to explore the ament (PCL), medial cruciate ligament (MCL), or lateral
efficacy of intra-articular morphine injections compared cruciate ligament (LCL) injury. Exclusion criteria were
with intra-articular lidocaine injections for acute knee traumatic arthrotomy, open fracture, polytraumatic in-
injuries. The primary outcome was relative VAS pain re- jury, closed head injury, dementia, altered mental sta-
duction. Secondary outcomes were the total cumulative tus, two or more suspected ligament injuries, vascular
use of ice as measured by number and duration of ice compromise, obvious infection, age less than 13 years,
applications and the total use of oral analgesics over the prosthetic knee joint, medication allergy to morphine
first 24 hours after intervention. or lidocaine, unwillingness to participate, or having re-
ceived pain medication in the ED other than the knee
injection. The enrolled patient demographics are listed
Methods
in Table 1.
This study was designed as a single-blind, randomized
controlled trial. Due to hospital and IRB constraints, All patients were consented by either the principal inves-
the investigators and providers performing the intra- tigator or an associate investigator using an approved
articular injections were unable to be blinded to the study-specific Brooke Army Medical Center IRB consent
medication used. However, the patients were blinded to form. Potential participants had the study explained to
which medication was used, and this information was them in a private location in the ED and were given a
never revealed to them. Intervention randomization was copy of the consent document to read as well as given an
achieved using an online random sequence generator. 9 opportunity to ask the investigator any questions. Once
the patient reached a decision on whether to participate,
A convenience sample of patients presenting to the San the investigator reviewed the risks and benefits of the
Antonio Military Medical Center ED between May study to ensure the patient understood the research. The
2012 and August 2013 with knee pain were identi- patient, consenting investigator, and witness all then
fied as possible participants. ED clinicians educated on signed the informed consent document. A copy of the
this research project through presentations at ED staff document was given to the participant, and the original
meetings and resident educational rounds as well as a was securely stored.

Table 1 Patient Characteristics
Patient Age, yr Sex Intervention Presenting Complaint Injury Mechanism
1 14 M Morphine and Right ankle and knee injury Twisted in football
lidocaine
2 38 M Lidocaine Left knee pain after Physical training
physical training
3 56 M Morphine Left knee pain Getting out of bed
4 47 F Morphine and Right lower extremity swelling Pain after waking up
lidocaine
5 — — Withdrew — —
6 76 M Lidocaine Left knee pain worsening — History osteoarthritis,
swelling increased activity
7 20 F Morphine and Left knee injury Mechanical fall from standing
lidocaine
8 46 F Morphine Left knee pain 5km run day earlier
9 — — Withdrew — —
10 74 M Morphine and Right knee pain Mechanical fall from standing
lidocaine

Intra-articular Morphine versus Lidocaine for Acute Knee Pain 75