5th May 2021
Non-pharmaceutical adjuncts such as cryotherapy are becoming increasingly popular and have evolved from simple ice sleeves (or gel packs), to more refined devices employing electronically controlled cold fluid or air circulation, used in the immediate postoperative period, following knee surgery, to address complications associated with pain, bleeding, oedema, and reduced range of movement.
The focus of this blog is a compelling study that has reviewed existing literature on the effects of cryotherapy following total knee arthroplasty (TKA). The study discusses the role of cryotherapy, the proposed pathophysiology behind its use, its evolution with time, and a review of the existing literature on its efficacy and potential risks associated with its use following TKA.
The study reviewed existing literature between January 1990 and November 2016. A total of 51 articles were analysed and 24 were selected based on clinical relevance.
The findings conclude that Cryotherapy is shown to provide some benefits but a severe lack of level 1 studies (Randomized Controlled Trial – RCTs) supporting its use make it difficult to reach a suitable conclusion, reporting that further multi-centre RCTs with representative populations and a fair comparison of devices are needed. It also postulates that the current controversial evidence, supporting it use, is potentially due to variation in the cryotherapy devices used and their application (type, frequency, or duration), making it difficult to derive a firm conclusion.
The following extracts from the study include references that are numbered as published:
Total knee arthroplasty (TKA) is an important option in the management of severe osteoarthritis. Despite excellent long-term results following TKA, the immediate postoperative period is often associated with pain, surgical blood loss, localised edema, resulting from tissue damage and the inflammatory response and reduced range of movement5.
These are considered crucial factors due to their influence on postoperative opiate use, requirement for blood transfusion and its associated risks6 as well as a negative impact on postoperative rehabilitation. This can result in increased length of stay and increased cost to the treating unit.7
Cryotherapy has been shown to provide some benefit in addressing these challenges but results are largely controversial.
Cryotherapy involves the application of a cold substance, such as ice, to the skin surrounding inflamed soft tissues and joints.
The proposed mechanism of action is that a reduction in temperature reduces intra-articular temperature (in the tissues below the skin) and limits pain through reducing nerve conduction velocity (the speed at which electrochemical impulses travel) in addition to promoting immediate vasoconstriction (narrowing of the blood vessels), reducing vascular spasm (a brief tightening of the muscle cells inside the walls of a blood vessel) and slowing down of blood flow, ultimately decreasing tissue edema.10
The intra-articular temperature reduction is transient (short lived).11 Studies in animal models have demonstrated that excessively low temperatures or prolonged cooling results in a paradoxical (contradictory) increase in local edema.12 . Despite immediate vasoconstriction and reduction in blood flow, cryotherapy could lead to delayed vasodilation and disruption of secondary hemostasis (the process that prevents and stop bleeding). Evidence also exists, showing that the local application of ice could impair hemostasis, leading to prolonged bleeding time, increased clotting time, reduced platelet aggregation (inability to form clots), and increased clot formation time, although this has not been shown to be an issue in patients without pre-existing coagulopathy.13 (a bleeding disorder),
The most investigated outcome measure in studies involving cryotherapy post-TKA is pain. Some authors have reported limited benefit of cryotherapy on alleviating pain14, or reducing blood loss15 and inconsistent findings on decreasing swelling and improving mobility16 post-TKA. Click here to review the findings on pain.
The study found that relatively few authors have investigated the effects of cryotherapy on postoperative swelling and oedema. Contrasting results were reported by Healy28 where a positive effect was noted with cryotherapy only when ice was exchanged every 1–2 h and a negative effect in the other patient group where ice was exchanged less frequently every 4 h. This study, however, was supported by a research grant from the cryotherapy device manufacturer, introducing a conflict of interest. Smith et al.22 found limited benefit of using cold therapy when compared to compression bandages up to 48 h post-TKA in their RCT. Levy and colleagues20 reported no improvement in postoperative oedema when cryotherapy was applied, although this was measured in only 20 of the 80 patients included in the study.
Range of motion
Restrictions in range of motion (ROM) can hinder early rehabilitation. Kullenberg et al.17 reported an increased range of flexion when cryotherapy was used post-TKA in their study of 86 patients. This study is, however, at risk of reporting bias after the authors failed to state the effects on knee extension. An improvement in ROM post-operatively (measured as flexion) was noted by Levy and Marmar20 in their RCT comparing the effects of Cryo/Cuff (Aircast, Vista, California, USA) to Robert Jones bandage. Mumith et al.29 noted further improvement both in ROM and cost when comparing a novel cooling product, Physicool (Physicool Ltd, London, UK) to Cryo/Cuff.
These findings are however in contrast to those from Healy et al.’s28 study where Cryo/Cuff dressing application was not associated with increase in ROM (measured as extension) postoperatively at any point. Similarly, Gibbons et al.23 found no improvement in postoperative motion associated with the use of cryotherapy with similar results echoed by Su et al.30 as well as Schinsky et al.’s31 study comparing low-cost ice/gel pack against circulating ice water cryotherapy.
Evolution of cryotherapy
Cryotherapy has gradually evolved over time. First generation cold therapy included basic gel packs and crushed ice in plastic bags. Second generation includes circulating ice water promoting cold therapy such as Cryo/Cuff, whereas third-generation devices enable electronic control of continuous cold therapy.27
A large disparity in the use of cryotherapy worldwide exists due to conflicting evidence relating to its benefits. Third-generation cryotherapy providers stated that this conflicting evidence was linked to improper cooling technique as traditional ice packs are unable to guarantee a sustained fixed temperature during cooling. This has led to the development of new advanced cryotherapy devices providing continuous extended cooling using continuous flow of cold air. Bech et al.16 compared the use of a continuous cooling icing device (DonJoy Iceman, DJO Canada, Mississauga, Ontario, Canada) against intermittent cooling via a standard ice bag in the first 48 h postoperatively and found no difference in pain or blood loss. Thienpont32 also noted no difference in postoperative pain, analgesic consumption, postoperative ROM, swelling or blood loss in patients receiving advance cryotherapy versus cold packs. The authors concluded that the higher economic costs of advance cryotherapy conferred no advantages over cheaper and more readily available ice packs.
Interest has recently grown in the combined use of compression and cooling therapy through cryopneumatic devices. Maximizing ROM is a major objective post-TKA. Su et al.30 found no difference for ROM, swelling or functional testing between a cryopneumatic device (GameReady) and ice packs. Similar findings were also reported by Holmström and Härdin33 in a prospective, RCT for the Cryo/Cuff when compared to epidural anesthesia. However, better outcomes were demonstrated in two-stage bilateral TKAs by Morsi18 with the use of these devices.
Risks of cryotherapy
Cryotherapy does have potential risks associated with its use. Human skin can be directly affected by hypothermia. Prolonged duration and overly low temperatures applied in addition to excessively high pressures can compromise skin circulation27. Frosbite occurs at temperatures around 10°C and prolonged cooling <5°C can result in necrosis and thrombosis.32 It has been suggested that cryotherapy should be contraindicated in individuals with cold urticarial (a skin reaction to cold that appears within minutes), cryoglubinemia (a medical condition in which the blood contains large amounts of cold sensitive antibodies), and paroxysmal cold haemoglobinuria (a rare type of anemia caused by the presence of cold-reacting autoantibodies).23 In addition, it has been recommended that at least 20 min of cessation should be encouraged between 2-h long cryotherapy sessions30.
Management of postoperative pain following TKA still poses a challenge. Non-pharmaceutical adjuncts such as cryotherapy are becoming increasingly popular and have evolved from simple ice packs to more refined devices employing electronically controlled cold fluid or air circulation. Current published evidence supporting its use is controversial. This is potentially due to variation in the devices used and their application (type, frequency, or duration). It is therefore difficult to derive a firm conclusion on the benefits of its use. Further research in the form of multicentre RCTs with representative patient populations is needed to examine the effect of cryotherapy on postoperative pain management, length of stay, and postoperative function post TKA and also to compare the devices available.
Sue Davenport – VP Marketing Communications
5th May 2021