To explore the application effect of time-selective acupoint application based on the midnight-noon ebb-flow theory in patients with postoperative constipation following knee arthroplasty.

Seventy-two patients who developed constipation after knee arthroplasty were divided into two groups based on admission order, 36 patients in each.The experimental group underwent time-selective acupoint application aligned with the midnight-noon ebb-flow theory, alongside routine care.The control group received non-time-selective acupoint application in addition to routine care.Time to first postoperative defecation, defecation duration, defecation intervals, overall treatment outcome, and PAC-QOL scores were compared between the two groups by t test and chi square test.

The experimental group experienced shorter times to first postoperative defecation, shorter defecation durations,and reduced defecation intervals compared to the control group (t=7.139, 4.971, 1.937, all P<0.001). The constipation improvement was also markedly better in the experimental group. Tthe experimental group showed higher total marked effective and total effective rates compared to the control group (χ²=7.35, 7.35, all P<0.05). Both groups exhibited improved PAC-QOL scores after intervention compared to the scores before intervention (t=7.448, 5.682, all P<0.001); the PAC-QOL score of experimental group was superior to the control group (t=2.125, P<0.05).

Time-selective acupoint application based on the midnight-noon ebb-flow theory demonstrates good efficacy in alleviating constipation in patients after knee arthroplasty.