Total knee arthroplasty is one of the most cost-effective and consistently successful surgeries performed in orthopedics. Despite the progress in surgical techniques and postoperative care, complications such as swelling and pain become the key of optimizing patients’ satisfaction.
In our study, the mean girths of the knee joint strikingly increased after surgery in both groups, as was described in previous studies. In conformity with a previous study, pain score increased to the highest level within 24 h after TKA. This is probably due to the variable intra-operative soft tissue trauma with consecutive secretion, bleeding, and swelling as well as to individual post-operative reaction.Blooding and damaged tissue caused by surgery will release inflammatory mediator like TNF-α, IL-1β, IL-6, IL-8, increasing vascular permeability, causing inflammatory exudation and thus leading to swelling and pain which is acute phase response (APR). APR is a systemic reaction to tissue injury and does not vary significantly difference in surgical techniques.
Cryotherapy is a Non-pharmaceutical treatment to relief of postoperatively pain and swelling, which involves the application of cold to the skin surrounding the injured soft tissues and in joint surgery is supposed to reduce the temperature in knee-joint. Low temperature will reduce local blood flow through vasoconstriction, which relieves the local inflammatory reaction, swelling and heat experience, and also will slow the conduction of nerve signals that potentially reducing pain transmission[10–12]. In addition, previous study has shown that a pleasant sensation evoked by knee icing also will reduce the pain intensity after TKA. Kullenberg et al.’s study showed water ice packs were more effective than epidural analgesia in reducing pain degree after TKA. Kuo et al. also confirmed the effect of ice pack on antis-welling and analgesic. Analysis from Thacoor A et al. showed that cryotherapy had certain efficacy in reducing swelling and pain degrees after TKA. Cryotherapy is applied to reduce the degree of swelling and pain whether in theory or clinical practice after trauma.
Several cryotherapy options are available including first-generation cold therapy like crushed ice in a plastic pack, new-generation advanced computer-assisted devices with continuous controlled cold therapy. The advantage of these latter devices is controlled-temperature modulation with cooling at a specific and continuous temperature for a prolonged time, introducing better effect of resolving pain and swelling than crushed ice pack. Morad Chughtai et al.reviewed 16 studies where various types of cryotherapy were assessed and compared, concluding continuous temperature devices are the most effective. However, using the new-generation means the much higher cost than traditional cryotherapy, which is unaffordable for most patients.
Mirabilite is a cheap hydrous sodium sulfate mineral which has the special physical properties of salt and always applied externally to relieve pain and swelling after trauma in traditional Chinese medicine. In traditional Chinese medical theory, mirabilite has a feature of clearing fire-evil which in modern medical theory we call inflammation and absorbing swelling. Some Chinese scholars show that by inhibiting reticuloendothelial system, mirabilite has a positive effect on anti-inflammation. Lu’s study in rabbits shows that mirabilite can significantly decrease the expression of IL-1, IL-6, TNF-α and the severity of inflammatory responses. In our study, the MIP group shows statistically significant lower knee girth at 48 h, 72 h postoperatively and VAS sore at 72 h postoperatively than WIP group, which suggests mirabilite and ice pack can synergetic control swelling and pain. In addition, the improvement of ROM at 72 h after surgery and the reduction of LOS in MIP group indicate that compare with ice pack alone, mirabilite with ice pack can accelerate the recovery process and discharge, therefore reducing unit treatment cost. Inspired by previous studies, we recorded and analyzed the postoperative degree of serum CRP. Although, there is no statistically significant correlation between CRP and ROM, VAS, girth difference at 72 h postoperatively, our study shows that serum CRP at 72 h after surgery of MIP group is significantly lower than WIP group. These results support the viewpoints described above. The anti-inflammatory function of mirabilite may be the reason for the better postoperative performance in MIP group. However, the mechanism of mirabilite anti-inflammatory and reducing pain and swelling still needs to be further confirmed and studied.
Although some previous studies reported on frostbite,deep vein thrombosis and further adverse effects after cryotherapy, there was no occurrence of any adverse event reported in 2 groups throughout our study. Our study shows that use of cryotherapy and mirabilite after TKA is safe.