A Study Comparing the Effectiveness and Safety of Extended Release (ER) Tramadol Hydrochloride (HCl)/Acetaminophen With Immediate Release (IR) Tramadol HCl/Acetaminophen in Participants With Moderate to Severe Postoperative Pain

The SPID is time-weighted sum of all observations of pain intensity difference (PID) collected at each measurement time point from Baseline to 48 hours. PID: Baseline pain intensity (PI) minus current PI; PI was assessed using 11-point numeric rating scale (NRS, 0=no pain to 10=worst pain imaginable). PI score ranges from 0-3 where 0=no pain and 3=severe pain. PI score of 0=NRS score of 0, PI score of 1=NRS score \>=1 and \<=3, PI score of 2=NRS score of \>=4 and \<=6 and PI score of 3=NRS score of \>=7 and \<=10. Total score for SPID at 48 hours (SPID48) ranges from -144 (worst) to 144 (best).

Time frame: Hour 48

Population: The per-protocol (PP) population included all randomly assigned participants who did not violate major eligibility criteria and whose SPID was calculated with actual measurements or adjusted values at all assessment time points.

The dosage of the rescue medication (rescue medications are medicines that are administered to the participants when the efficacy of the study drug is not satisfactory, or the effect of the study drug is too great and is likely to cause a hazard to the participant, or to manage an emergency situation) because of insufficient pain relief was measured after administration of the study drug. Rescue medications allowed were oral or injection of tramadol HCl (intramuscular or intravenous injection).

Time frame: Baseline up to Day 3

Population: The intent-to-treat population included all randomly assigned participants. Here, 'N' specifies those participants who were evaluable for this outcome measure.

The frequency of the rescue medication (rescue medications are medicines that are administered to the participants when the efficacy of the study drug is not satisfactory, or the effect of the study drug is too great and is likely to cause a hazard to the participant, or to manage an emergency situation) because of insufficient pain relief was measured after administration of the study drug. Rescue medications allowed were oral or injection of tramadol HCl (intramuscular or intravenous injection).

Time frame: Baseline up to Day 3

Population: The intent-to-treat population included all randomly assigned participants. Here, 'N' specifies those participants who were evaluable for this outcome measure.

The PGIC was used to assess the degree of participant's overall improvement with treatment, and participants were instructed to assess how much the overall status had been improved after investigational product administration compared to baseline in 7 grades (1=Very much improved and B=Very much worsened).

Time frame: Day 3

Population: The intent-to-treat population included all randomly assigned participants. Here, 'N' specifies those participants who were evaluable for this outcome measure.

The SPID is time-weighted sum of all observations of PID collected at each measurement time point from Baseline to 24 hours. PID: Baseline PI minus current PI; PI was assessed using 11-point NRS, 0=no pain to 10=worst pain imaginable. PI score ranges from 0-3 where 0=no pain and 3=severe pain. PI score of 0=NRS score of 0, PI score of 1=NRS score \>=1 and \<=3, PI score of 2=NRS score of \>=4 and \<=6 and PI score of 3=NRS score of \>=7 and \<=10. Total score ranges from -18 (worst) to 18 (best) for SPID6, -36 (worst) to 36 (best) for SPID12 and -72 (worst) to 72 (best) for SPID24.

Time frame: Hour 6, 12, 24

Population: The intent-to-treat population included all randomly assigned participants. Here, 'N' (number of participants analyzed) specifies those participants who were evaluable for this outcome measure.

The SPRID is sum of SPID and TOTPAR. In SPID, PI score ranges from 0-3 where 0=no pain and 3=severe pain. PI score of 0=NRS score of 0, PI score of 1=NRS score \>=1 and \<= 3, PI score of 2=NRS score of \>=4 and \<=6 and PI score of 3=NRS score of \>=7 and \<=10. In TOTPAR, pain relief score ranges from 0-4 (0=no change, 1=slight relief, 2=moderate relief, 3=fair relief, 4=pain resolved completely). Total score ranges from -18 (worst) to 42 (best) for SPRID6, -36 (worst) to 84 (best) for SPRID12, -72 (worst) to 168 (best) for SPRID24 and -144 (worst) to 336 (best) for SPRID48.

Time frame: Hour 6, 12, 24, 48

Population: The intent-to-treat population included all randomly assigned participants. Here, 'N' specifies those participants who were evaluable for this outcome measure.

The time until administration of the first rescue medication (rescue medications are medicines that are administered to the participants when the efficacy of the study drug is not satisfactory, or the effect of the study drug is too great and is likely to cause a hazard to the participant, or to manage an emergency situation) because of insufficient pain relief after administration of the study drug was recorded. Rescue medications allowed were oral or injection of tramadol HCl (intramuscular \[directly into muscle\] or intravenous injection \[directly into vein\]).

Time frame: Baseline up to Day 3

Population: The intent-to-treat population included all randomly assigned participants. Here, 'N' specifies those participants who were evaluable for this outcome measure.

Pain relief was measured on a 5-point categorical scale of 0-4 (0=no change, 1=slight relief, 2=moderate relief, 3=fair relief, 4=pain resolved completely). TOTPAR was calculated as the time-weighted sum over all pain relief up to 48 hours. Total score ranges from 0 (worst) to 24 (best) for TOTPAR6, 0 (worst) to 48 (best) for TOTPAR12, 0 (worst) to 96 (best) for TOTPAR24 and 0 (worst) to 192 (best) for TOTPAR48.

Time frame: Hour 6, 12, 24, 48

Population: The intent-to-treat population included all randomly assigned participants. Here, 'N' specifies those participants who were evaluable for this outcome measure.