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Cryotherapy: to ice or not to ice
- November 13, 2016
- Posted by: Pieter Kroon
- Category: Uncategorized
A literature review
Lucas Pratt PT, DPT, FAAOMPT
Cryotherapy is one of the most commonly used modalities in treating soft tissue injuries. The use of cryotherapy is taught and advocated for in most medical and physical therapy schools to treat the cardinal inflammatory signs of heat, redness, and swelling that are present in acute injuries. Physicians often prescribe ice packs to their patients following injuries, and physical therapists commonly include cryotherapy into their plan of care. Despite the long history of cryotherapy usage, there is a lack of evidence to support it; in fact, there is recent evidence demonstrating cryotherapy’s negative effects on the healing process.
A recent article published in the International Journal of Sports Physical Therapy showed that cryotherapy performed by members of the Sports Physical Therapy section of the APTA was applied with a large amount of variability, and not according to the limited evidence available1. Because of this lack of consistent application of cryotherapy across our profession, it is imperative that physical therapists–as a Doctorate-level profession– review the current evidence on cryotherapy application and modify their practice accordingly.
Two systematic reviews on cryotherapy were published in 2004. Hubbard and Denegar2 stated that ice application was shown to reduce pain temporarily, but questioned the efficacy of its use on outcomes. Bleakly et. al.3 concluded that compression had positive effects on outcomes, but there was insufficient evidence to support the use of cryotherapy.
In Bleakly’s follow-up 2010 meta analysis4, fourteen high quality studies on the effects of cryotherapy were included. As this is the most recently published meta-analysis on cryotherapy, we will more closely examine the findings of this study. The four main effects of cryotherapy discussed in this study are:
Secondary cell injury: Ice application may reduce the effects of acute inflammation damaging healthy cells around the injured area. The studies show that cryotherapy reduces secondary cell death, but constant ice application of five to ten hours is required to have this effect.
White Blood Cells (WBCs): The WBCs that are activated following a soft tissue injury contribute to the healing process by removing necrotic debris, releasing cytokines, and begin the respiratory burst process that releases antibacterial agents. The studies showed that cryotherapy application led to significantly lower amounts of WBCs in the tissue.
Apoptosis: The studies showed that cryotherapy application for one hour can significantly lower apoptotic muscle cells.
Blood flow and Edema: The studies showed contradicting evidence on the effect of cryotherapy. “Some studies found that ice application did not significantly change capillary diameter, arteriole diameter, or capillary velocity after injury. In contrast, others found that ice either significantly increased or decreased arteriole diameter after injury.”
The authors report that the studies they reviewed were limited by the fact that they were all performed on cat or mouse models. They conclude with the following statements: “Cryotherapy can have an influence on key inflammatory events at a cellular and physiological level… However, the relative benefits of these effects have yet to be fully elucidated and it is difficult to contextualize within a human model.”
Bleakley also published a study in 2010 on human subjects5 which found that for a decrease of cell metabolism to occur from cryotherapy, the target tissue much reach 5-15 degrees C; however, the study found that even superficial muscle temperatures on lean athletes do not get lower than 21 degrees C with cryotherapy. Bleakley et. al. then published a human model systematic review in 20126 that concluded that cryotherapy reduces skeletal muscle contraction, which temporarily reduces lymphatic drainage at the site, and that athletes are at a significant performance disadvantage if they return to sport immediately after 20 minutes of icing.
Takagi et. al.7 demonstrated that compared to a control group that received no treatment, the experimental group of rats that received a single application of cryotherapy application for 20 minutes had less macrophages within the necrotic muscle fibers at 12 hours, leading to less necrotic tissue clean up, reduced regenerating muscle cells at 3 days, smaller regenerating muscle cells at 4 days, reduced maturation of regenerating cells at 14 days, and significantly less regenerating muscle fibers and abnormal collagen formation surrounding muscle fibers at 28 days. Their conclusion: “Judging from these findings, it might be better to avoid icing although it has been widely used in sports medicine.”
Tseng et. al.8 performed a study to determine if cryotherapy reduces delayed onset muscle soreness, and found that 15 minutes of ice application following a triceps workout caused a significantly increased the amount of creatine kinase and myoglobin, objective signs of muscle tissue overload. They concluded that cryotherapy delays recovery from eccentric exercise-induced muscle damage.
Clinical Implication: The current evidence does not support the use of cryotherapy for soft tissue injuries other than to temporarily reduce pain. Not only does cryotherapy performed on human models not cool the target tissue down enough to achieve decreased cell metabolism, but it delays recovery of muscle damage in humans, and a current animal model study shows that cryotherapy worsens the regeneration process following soft tissue injuries. Based on the current evidence, clinicians must reconsider the use of cryotherapy in their practice.
- Hawkins SW, Hawkins JR. CLINICAL APPLICATIONS OF CRYOTHERAPY AMONG SPORTS PHYSICAL THERAPISTS. International Journal of Sports Physical Therapy. 2016;11(1):141-148.
- Hubbard TJ, Denegar CR. Does cryotherapy improve outcomes with soft tissue injury? J Athl Train. 2004;39(3):278-279.
- Bleakley C, McDonough S, MacAuley D. The use of ice in the treatment of acute soft-tissue injury: A systematic review of randomized controlled trials. Am J Sports Med. 2004;32(1):251-261.
- Bleakley, C M and Davison, Gareth W (2010) Cryotherapy and inflammation: evidence beyond the cardinal signs. Physical Therapy Reviews, 15 (6). pp. 430-435.
- Bleakley CM, Hopkins JT. Is it possible to achieve optimal levels of tissue cooling in cryotherapy? Phys Ther Rev. 2010;15(4):344-350.
- Bleakley CM1, Costello JT, Glasgow PD. Should athletes return to sport after applying ice? A systematic review of the effect of local cooling on functional performance. Sports Med. 2012 Jan 1;42(1):69-87.
- Takagi, R, et al. Influence of Icing on Muscle Regeneration After Crush Injury to Skeletal Muscles in Rats. J of App Phys. February 1, 2011 vol. 110 no. 2 382-388.
- Tseng CY1, Lee JP, Tsai YS, Lee SD, Kao CL, Liu TC, Lai C, Harris MB, Kuo CH. Topical cooling (icing) delays recovery from eccentric exercise-induced muscle damage. J Strength Cond Res. 2013 May;27(5):1354-61.
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