Analgesic Effect of Gabapentin on Post-Operative Pain After Arthroscopic Anterior Cruciate Ligament Reconstruction

To the Editor
Mardani-Kivi et al presented results about a triple blinded randomized controlled trial with gabapentin in patients that underwent anterior cruciate ligament (ACL) reconstruction (1). In their manuscript, the introduction section is very illustrative about the subject. With respect to methodology, it is well known that the physical diagnosis of ACL injury is particularly difficult in several patients, and partial ACL tears are also difficult to diagnose on physical examination. In this particular case, how did the authors obtain the diagnosis of ACL in the patients? Likewise, ACL reconstruction can be delayed several weeks or months until the swelling has decreased and there is an appropriate range of motion. For this reason, I want to ask: was the cause of the ACL injury homogeneous in all patients?; was the time delay of the surgery the same for everyone; and was the type of damage the same for all participants?
Meperidine is an opioid with analgesic effects. The American Pain Society and the Institute for Safe Medication Practice (ISMP) do not recommend meperidine use as pain relieving medication or they recommend it only in very special cases and with many precautions during its administration (2, 3). What was the rationale of the authors choosing meperidine as analgesic drug? In this same sense, authors did not indicate in their manuscript whether meperidine was administered by oral, intramuscular or intravenous pathways or patient-controlled analgesia. The time schedule of meperidine administration was not indicate in the manuscript; was meperidine administered q4h or q6h? How many doses were received by patients?
I think it was a mistake to publish the demographic data of all patients (n=114). You had to eliminate the patients deleted in the presentation of the demographic characteristics of the patients (n=108), that is more correct. Table 2 and 3 were poorly prepared. Table 2 has missing data about the results at 24 hours in the placebo group. Table 3 does not specify the meaning of the values (milligrams or administration times or what the units were?)(Table 1, 2).
Finally, pre-emptive analgesia is defined as the treatment that is initiated before and is operational during the surgical procedure in order to reduce the physiological consequences of nociceptive transmission provoked by the procedure (4). Do authors have any idea or hypothesis about the possible mechanism of gabapentin to produce pre-emptive analgesia in your patients? Are the injury and the surgical technique employed in your study candidate to pre-emptive analgesia? Was the meperidine utilization in your study the better option to get pre-emptive analgesia?