To study the efficacy of two different types of analgesic methods after unilateral primary total knee arthroplasty (TKA) to find an effective analgesic.

The present study retrospectively reviewed the medical records of 40 patients who were diagnosed as knee osteoarthritis and underwent unilateral primary TKA with the combining femoral triangle block (FTB) and the interspace between the popliteal artery and the capsule of the posterior knee (IPACK) as the combining FTB and IPACK group. A total of 40 patients with the same diagnosis underwent TKA with intra-articular cocktail analgesic mixture? injection at the same time as the conventional group. All the patients received the PCA pump for analgesia at postoperative 48 h. The main indexes were postoperative knee joint resting and activity pain (VAS), and muscle strength of the affected limb; secondary indexes were anesthetic consumption, total morphine consumption, range of motion, and complications (such as nausea and vomitting). The statistical methods included repeated measurement data analysis of variance, Student-t test, chi-square test or Fisher exact probability method analysis.

There was no difference in the general data of each treatment group. Compared with the conventional group, the quadriceps muscle strength of the combining FTB and IPACK group was higher with statistical differences at post operation (F=186.10, 37.47, 56.65, 53.16, 39.14, 56.04 respectively, all P<0.05). At two, six, 12, 24, 48, and 72 h post operative, the active pain, in the six times observations after surgery, was better than that of the conventional group (F=28.33, 12.55, 24.89, 93.35, 59.20, 45.10, all P<0.05). Resting pain was smaller than the conventional group at postoperative two, six, 12, 48 and 72 h (F=44.07, 16.50, 7.08, 5.39, 5.14, all P<0.05). Morphine consumption, anesthetics consumption, and hospitalization time were lower than the conventional group, the difference being statistically significant (P<0.05). There were no differences between the two groups in postoperative wound healing, infection incidence, rash, respiratory depression, DVT, and urinary retention, and there were also no differences in PONV (all P>0.05).

Combining FTB and IPACK significantly increased the quadriceps muscle strength of patients, together, relieving early pain and reducing the amount of anesthetic consumption at postoperative different intervals.