To The Editor:
We wish to congratulate Stewart et al. for their article, "The Effect
of Intra-Articular Methadone on Postoperative Pain Following Anterior Cruciate
Ligament Reconstruction"
(2005;87:140-4), as it showed
that intra-articular methadone in certain doses can be used safely in the
knee.
The authors stated that it is known that intra-articular narcotics have
proven efficacy for providing pain relief following knee arthroscopy, but this
effect is short-lived. They hypothesized that methadone, with its long serum
half-life, could provide improved and prolonged pain relief in arthroscopic
reconstructions of the anterior cruciate ligament, but they found that
methadone does not provide improved postoperative analgesia.
Our main concern with this study is that, although the authors excluded the
use of tourniquets to prevent other pain sources in their patient group, we
believe that with arthroscopic reconstructions of the anterior cruciate
ligament, the donor site itself is an important source of extra-articular
pain. In particular, harvesting of a bone-patellar tendon-bone autograft
causes pain, and this site is completely extra-articular. We wonder whether
there is any logical explanation of the pain relief mechanism concerning an
extra-articular donor site when intra-articular injection techniques are used.
One possibility is an analgesic effect through systemic absorption and the
analgesic and anti-inflammatory properties of morphine in
synovium1, but this can be effective only in the intrasynovial part
of the procedure.
We believe that intra-articular injection of methadone should be tried in a
substantial number of studies in which the procedure is all intra-articular,
such as arthroscopic meniscal or chondral surgeries. It may have been better
to have tried it in these kinds of procedures first.
We appreciate the interest of Dr. Muratli and colleagues in our paper. We
agree that the donor site in anterior cruciate ligament reconstruction is a
substantial source of postoperative pain for both hamstrings and
bone-tendon-bone autograft procedures. We also agree that this pain is
completely extra-articular, and any intra-articular analgesic—either
narcotic or local anesthetic—should have little or no effect on this
pain source.
Any extra-articular source of pain in our study was addressed with
multimodal pain therapy. This consisted of cold therapy through local
application of ice postoperatively, preemptive analgesia with ketorolac during
the procedure, and systemic analgesia as needed. This was all standardized,
and all patients received the same multimodal treatments with the exception of
the amount of systemic analgesia, which was recorded and used as an outcome
measurement.
Intra-articular morphine was shown in our study to be effective in
relieving overall pain compared with methadone or placebo. We assume that this
intra-articular morphine was addressing only the pain from within the knee
joint and had no effect on the extra-articular donor site. Regardless, the
patients had less overall pain with intra-articular morphine, while methadone
was no better than placebo.
There are several reasons why we chose anterior cruciate ligament
reconstruction as our model for introducing intra-articular methadone as a
possible long-acting analgesic. This is a commonly performed procedure, and
the postoperative pain can be substantial and long lasting. This pain can
interfere with postoperative rehabilitation and can compromise the surgical
outcome. There is a real need for improved pain control in anterior cruciate
ligament reconstruction. In our experience, these issues are not nearly as
problematic with completely intra-articular arthroscopic procedures such as
meniscal or chondral repair.
Marchal JM, Delgado-Martinez AD, Poncela
M, Valenzuela J, de Dios Luna J. Does the type of arthroscopic surgery modify
the analgesic effect of intraarticular morphine and bupivacaine? A preliminary
study. Clin J Pain.2003;19:
240-6.19240
2003
[PubMed][CrossRef]