As physiotherapists, we get the question almost daily. People have heard it from their friends and from their coaches. It is common knowledge. Ice reduces pain and accelerates healing. Or does it?

 

Well-known websites disseminate this information without reserve. For the general public, Wikipedia states that “cryotherapy is used in an effort to relieve muscle pain, sprains and swelling after soft-tissue damage or surgery. It is commonly used to accelerate recovery in athletes post exercise”.

 

For physiotherapists, Physiopedia clearly says that “ice application is the simplest and oldest way to treat injuries. Its worldwide use spread because of its effectiveness, convenience, low cost and ease of transportation”.

 

Theoretically, this would mean that, people living around the Equator likely don’t heal from injuries as well as people living in the Great North. This begs the question: what were people doing before freezers were invented?

 

 

Relying on actual scientific evidence

From a practical perspective, we need to rely on actual scientific evidence. Cryotherapy could potentially be useful after surgery. For example, a systematic review of 74 randomised clinical trials looked at pain management strategies after anterior cruciate ligament reconstruction surgery [1]. Among the 10 studies that evaluated the effects of cryotherapy, 3 showed benefits on pain, and 2 found less opioid use 24 hours after surgery. At the 48-hour mark, only one study found that cryotherapy was useful for pain. Still, this leaves quite a few studies showing no benefits of ice.

 

In a Clinical Practice Guideline on the management of people after total knee arthroplasty, the American Physical Therapy Association states that “physical therapists should teach patients and other care givers use of cryotherapy and encourage its use for early postoperative pain management” [2]. Interestingly, this recommendation stems from two studies (1 high-quality and 1 low-quality) favoring cryotherapy over control interventions for pain management, even though another similar high-quality study found no benefit.

 

According to another study reviewed for the guideline, pain management could be improved when using a “cold spray” for 40 seconds, at a distance of about 10 cm, while patients do exercise after total knee arthroplasty [2]. What the guideline doesn’t say is that the “benefit” was of 0.8/10 on a visual analog scale after 3 and 28 days – not even close to reaching a clinically significant level for such a cumbersome intervention. Furthermore, would any difference have been detected should the control group have gotten a placebo air spray, instead or getting nothing?

 

Cryotherapy remains a low-risk intervention, with potential benefits on pain. Some studies suggest it is as useful as pain medications [2]. Thus, cryotherapy can certainly be part of the options to manage pain after surgery, if found useful in certain patients. The opioid crisis in British Columbia certainly supports the use of any safe intervention that helps to reduce intake of pain medications.

 

A Cochrane review summarizing 9 randomised clinical trials and data (n=998 women) concluded that although the effects were relatively small, “cooling treatments may help relieve perineal pain after having a baby”, [3]. Interestingly, the authors also stated that “further research is needed to see if cooling affects how well the tears or cuts heal”. Technically, scars are acute soft-tissue injuries, and recent evidence raises that question.

 

 

PEACE & LOVE, but no ice

This is why ice was left out of PEACE & LOVE, the latest acronym on how to manage acute soft-tissue injuries [4]. Not only has ice not really shown any benefits for healing, but it could also be detrimental. For example:

• Laboratory studies have found that ice applied immediately after a muscle injury leads to delayed muscle regeneration in animals [5, 6].
• In humans, topical cooling after eccentric muscle activity led to increased fatigue, pain and muscle damage compared to sham [7].
• In two other small studies in humans, ice massage led to no difference in muscle strength or soreness compared to controls [8, 9].
• Conversely, a comparison of ice massage to passive recovery after eccentric exercise found reduced soreness at 72 hours in the ice massage group [10].
• Thus, the evidence on the influence of cryotherapy on muscle regeneration appears to be inconclusive and, based on small studies, potentially detrimental.
• And believe it or not, there is no evidence supporting the use of cryotherapy after an ankle sprain. Ice has no clinically significant effects on symptoms, swelling, or return to function [11, 12].

 

 

Inflammation – friend or foe?

One might think that inhibiting inflammation after a muscle injury could be beneficial, but it seems to be more complicated than that. Inflammation is a complex, orchestrated cascade which includes many signals that are essential to kickstart healing [13].

 

While it is true that experiments have shown getting rid of neutrophils can improve recovery after muscle injury [14], it is also true that removing macrophages delays recovery - likely because macrophages help orchestrate muscle regeneration [15], so it may not actually be a great idea to mess with them.

 

Using ice to try and blunt the inflammatory process is therefore complicated by the importance of inflammation for healing.

 

In summary, ice could potentially be useful after surgery, especially if it helps reducing the use of pain medications. If a patient finds ice helpful, why not use it?

 

But after muscle or ligament injury, we just can’t recommend icing, because there’s no supporting evidence. And we could even recommend against it, based on the current state of research. Instead, provide some PEACE & LOVE, and let nature play its role.

 

References

1. Davey MS, Hurley ET, Anil U, et al. Pain management strategies after anterior cruciate ligament reconstruction: A systematic review with network meta-analysis. Arthroscopy 2021;37: 1290-300.
2. Jette DU, Hunter SJ, Burkett L, et al. Physical therapist management of total knee arthroplasty. Phys Ther 2020;100: 1603-31.
3. East CE, Dorward ED, Whale RE, et al. Local cooling for relieving pain from perineal trauma sustained during childbirth. Cochrane Database Syst Rev 2020;10: CD006304.
4. Dubois B, Esculier JF. Soft-tissue injuries simply need peace and love. Br J Sports Med 2020;54: 72-3.
5. Shibaguchi T, Sugiura T, Fujitsu T, et al. Effects of icing or heat stress on the induction of fibrosis and/or regeneration of injured rat soleus muscle. Journal of Physiological Sciences 2016;66: 345-57.
6. Takagi R, Fujita N, Arakawa T, et al. Influence of icing on muscle regeneration after crush injury to skeletal muscles in rats. Journal of Applied Physiology 2011;110: 382-8.
7. Tseng CY, Lee JP, Tsai YS, et al. Topical cooling (icing) delays recovery from eccentric exercise-induced muscle damage. J Strength Cond Res 2013;27: 1354-61.
8. Howatson G, Gaze D, van Someren KA. The efficacy of ice massage in the treatment of exercise-induced muscle damage. Scand J Med Sci Sports 2005;15: 416-22.
9. Crystal NJ, Townson DH, Cook SB, et al. Effect of cryotherapy on muscle recovery and inflammation following a bout of damaging exercise. Eur J Appl Physiol 2013;113: 2577-86.
10. Adamczyk JG, Krasowska I, Boguszewski D, et al. The use of thermal imaging to assess the effectiveness of ice massage and cold-water immersion as methods for supporting post-exercise recovery. Journal of Thermal Biology 2016;60: 20-5.
11. Miranda JP, Silva WT, Silva HJ, et al. Effectiveness of cryotherapy on pain intensity, swelling, range of motion, function and recurrence in acute ankle sprain: A systematic review of randomized controlled trials. Phys Ther Sport 2021;49: 243-9.
12. Vuurberg G, Hoorntje A, Wink LM, et al. Diagnosis, treatment and prevention of ankle sprains: Update of an evidence-based clinical guideline. Br J Sports Med 2018;52: 956.
13. Scott A, Khan KM, Roberts CR, et al. What do we mean by the term "inflammation"? A contemporary basic science update for sports medicine. Br J Sports Med 2004;38: 372-80.
14. Iwahori Y, Ishiguro N, Shimizu T, et al. Selective neutrophil depletion with monoclonal antibodies attenuates ischemia/reperfusion injury in skeletal muscle. Journal of Reconstructive Microsurgery 1998;14: 109-16.
15. Liu X, Liu Y, Zhao L, et al. Macrophage depletion impairs skeletal muscle regeneration: The roles of regulatory factors for muscle regeneration. Cell Biology International 2017;41: 228-38.