As the aging of the population and the increasing requirement of the life quality of the elders, total knee arthroplasty, the most effective method to cure advanced KOA, is urging these years. However, postoperative pain and bleeding are still the head-paining issue for both the patients and the arthrologists. Satisfied pain-relieving intervene and bleeding-reduced treatment play pivotal role in acquiring an ideal rehabilitation .
Postoperative pain is a nightmare for patients. Studies showed that about 30% of patients suffered from moderate pain after TKA, and about 60% of patients reached severe pain . According to Dorr’s survey , only less than half of the early pain after TKA can be effectively controlled. Severe postoperative pain will exert inverse effect on the cardiovascular, endocrine, respiratory and other systems, as well as the internal environment balance, which may also trigger the psychological disorders, such as anxious or insomnia after the operation. In particular, the pain will induce the muscular tension of the knee, which may bring out the resistance for early activity and functional exercise, leading to the unsatisfied rehabilitaion. Reuben et al.  also believe that uncontrolled early pain after TKA is one of the main causes of postoperative chronic pain.
The pain after TKA is mainly manifested as moderate to severe pain, which is caused by the mechanical damage of surgical dissection. As the constant stimulation of massive pain mediator, lower pain threshold is accumulated for the peripheral nerve pain receptors, meanwhile the stimulation is conducted through nerves to the central nervous system which prolonged the central response time, leading to the increased intensity and eventually a hypersensitivity response.
Effective postoperative analgesia not only alleviate the patient’s subjective feelings of pain, but also reduce post-operative complications such as deep vein thrombosis and pulmonary embolism in the lower limbs caused by lack of exercise. Research revealed that timely active exercise is the most effective method to prevent the adverse thrombosis event, nevertheless, the prerequisite for effective functional exercise after surgery is to obtain the satisfied analgesia. What’s more, early active exercise is essential for the recovery of knee function . In addition, the post-operative pain is also closely correlated with patients’ age, gender, type of operation, and operation time. No statistical difference is observed in the listed influencing factors in present study.
Massive bleeding, including obvious bleeding and invisible bleeding, often occures after TKA. Bleeding is highly correlated with gender, coagulation function, intraoperative application of tourniquet, prosthesis design, surgical technique, and the use of hemostatic drugs . Obvious bleeding is mainly reflected in the postoperative drainage, whilst postoperative swelling of the soft tissue around the knee joint is the main reflection of invisible bleeding. According to Pattison’s  research, invisible bleeding is mainly caused by hemolysis and bleeding into the soft tissue space. Excessive bleeding after surgery often results in a reduced hemoglobin, which leads to anemia and delays early rehabilitation. Anemia can be corrected by allogeneic blood transfusion in a short time, however, many complications of the blood transfusion, such as the transmission of infectious diseases, side effect of blood transfusion and immunosuppression may follow . Meanwhile, the shortage of blood reserves in recent years has made it more and more difficult to transfuse allogeneic blood. Therefore, effective methods to reduce peri-operative pain and postoperative bleeding is essential. Intraoperative joint perfusion with iced normal saline and cocktail is undoubtedly a simple and easily performed method.
Nowadays, cold compress therapy is employed to treat various acute injuries [9, 10]. Cold compress can dispel the inflammation mediators by constricting capillaries to intercept the progression of inflammation, contributing to the hemostatic and analgesic effects. Research in acute soft tissue injury revealed that pressurized cold compress treatment can significantly slow down the speed of nerve conduction and reduce the sensitivity of local nerve endings to relieve the pain . The present study showed that the VAS scores of patients in the ice-salt water group and ice-salt-salt-mixed cocktail group were significantly lower than those of the control group at 24, 48, and 72 hours post-operation (P < 0.05).
Cocktail therapy in TKA has been clinically applied widely, although there is no universal criteria for the recipe. We modified the cocktail recipe basing on the consensus of experts. In addition to ropivacaine and epinephrine, morphine and triamcinolone acetonide were also formulated and diluted with normal saline to 60ml. Intraoperative extensive injection of cocktails could directly block the signalling transduction of vast pain receptors in the knee joint cavity to achieve a good analgesic effect . Generally, ropivacaine, lidocaine and bupivacaine are used for local anesthesia. Due to the advantage of long action time, strong anesthetic intensity and small cardiovascular side effects, ropivacaine was selected in our cocktail. On the other hand, ropivacaine presents exert little effect in blocking the motor nerves, and it does not delay the early postoperative rehabilitation. Although it is a central opioid analgesic, morphine also has periphery receptors. The topical application not only presents a good analgesic effect, but also can avoid the side effect of morphine such as urine storage, lethargy, and dry stool to a certain extent. Adrenaline can constrict local blood vessels, delay the absorption and metabolism of the cocktail, and extend the action time of the cocktail.
Through clinical assessment, the analgesic effect of iced normal saline combined cocktail is much better than just using pure iced normal saline(P < 0.05). Thus, the postoperative pain and the inflammation are significantly reduced. As a result, patients can rehabilitate earlier, contributing to the promotes the recovery of knee function. The postoperative HSS scores of patients on the third day after surgery in the iced normal saline group and the iced normal saline combined with cocktail group were markedly higher than that of the control group(P < 0.05).
Routinely intra-operative extensive soft tissue loosening, osteotomy and patella repair in TKA lead to enlarged wounds and serious bleeding. How to reduce post-operative bleeding, reduce the incidence of blood transfusion and related postoperative complications is the special attention should be paid after TKA. Previous report showed that cold compresses after TKA proved to significantly lower pain, reduce bleeding and improve the sleep quality . Iced perfusion can promote the capillary constriction to decrease the bleeding, on the other hand, the increased local pressure of the joint cavity after the perfusion of ice normal saline could compress the capillaries in the wound, thereby achieving the hemostasis.
Elastic bandage dressing was also applied in our clinical practice to reduce the leakage of the broken ends of the lymphatic vessels in the joint cavity and promote the venous blood return. Recent years, ranexamic acid is proved to exert pivotal role in controlling hyperfibrinolytic bleeding after TKA, intraoperative and postoperative application of ranexamic acid significantly reduced the incidence of blood tranfusion and the postoperative inflammation . In the present study, drainage in the iced normal saline group and the iced normal salined mixed with cocktail group was significantly lower than that in the control group at 24 hours after surgery (P < 0.05). Considering the risks of normal saline penetrating into the soft tissue around the joints to induce the joint swelling, we measure the circumference of the thigh 10 cm above the knee after TKA. No statistical differential circumstance was observed between the joint cavity perfused and control group, which indicated that the perfusion therapy did not increase the postoperative swelling.