|Abstract / Summary
Postoperative pain after shoulder surgery is often considerable, and sufficient treatment is necessary
to minimize suffering and improve rehabilitation. Postoperative pain usually subsides during the
healing period, but some patients experience chronic pain which reduces their quality of life.
Our aim was to investigate  the effectiveness of local infiltration analgesia compared to
interscalene brachial plexus catheter in shoulder replacement,  the analgesic benefit of a high
dose of 40 mg dexamethasone compared to the usual 8 mg in minor arthroscopic shoulder surgery,
and  the epidemiology of persistent pain 1-2 years after shoulder replacement.
In study I, 61 shoulder replacement patients were randomized to receive local infiltration analgesia
or a brachial plexus catheter, and postoperatively reported their analgesic use, pain intensity, and
side effects for 3 days, with final follow-up after 3 months for complications. The primary outcome
was 24-hour opioid consumption, and our results showed that this outcome was poorest in the local
infiltration analgesia group and that this also applied to pain scores on the day of surgery.
In study II, which was blinded and GCP-monitored, 73 shoulder arthroscopy patients were
randomized to receive dexamethasone 40 mg, 8 mg, or placebo. Again, patients reported pain
intensity, analgesic consumption, and side effects for 3 days, but in this case with final follow-up
after 2 months for complications. There were no significant differences in pain scores or analgesic
consumption between the 40 mg and 8 mg group. However, a dose-response relationship was
confirmed when the placebo group was included in analysis.
In study III, 538 patients who had received a shoulder replacement in Denmark 1-2 years earlier
answered a questionnaire describing their current pain, pain treatment, and possible risk factors. The
prevalence of constant/daily pain which interfered much/very much with daily activities was 22 %;
higher for fracture patients (29 %) than for osteoarthritis patients (16 %). Thirteen percent reported
neuropathic pain characteristics. Risk factors for fracture patients were previous osteosynthesis,
pain elsewhere, severe acute postoperative pain, and for osteoarthritis patients hemi-arthroplasty
compared to total arthroplasty, and severe acute postoperative pain.
In conclusion, we present results showing poor effect of LIA for use in shoulder replacements, and
the method cannot be recommended. We provide evidence that there is very limited analgesic
benefit of increasing the dose of dexamethasone for use in shoulder arthroscopy, although the
analgesic effect was reaffirmed. Finally, we provide data to support that persistent pain after
shoulder replacement is a major problem, especially among fracture patients, and these results can
serve to guide future investigations.