Why does icing work best when applied shortly after tendinitis symptoms appear?

Question

It is recommended to apply ice as soon as possible after tendinitis symptoms appear. Is icing quickly after the injury much more effective than after a while (e.g. a few days), and if so why?

This Yahoo answer post by Susan says :

Apply ice in the first 48 hours following an injury is effective in that it will constrict blood vessels, thereby limiting fluid rushing to the area and reducing swelling. The cold can also be helpful in pain reduction. With an injury, a knee included, the R.I.C.E. method is best to employ- Rest, Ice, Compression and Elevation. Rest the area, apply Ice (15-20 minutes at a time, never directly on the skin and always allowing the skin to return to normal body temperature before reapplication- this usually means waiting at least 60 minutes between applications), Compression as in an Ace bandage or similar wrap and Elevating the affected limb on pillows or in a sling above the level of the heart. You can take Acetaminophen or Ibuprofen for pain relief with Ibuprofen being the better choice due to its anti-inflammatory properties. It is best to take it with food.

Icing an injury will not stiffen a joint.

The cons to icing an injury are leaving the ice on for too long a period of time or icing the injury beyond the first 48 hours. After the first 48 hours, moist heat should be used.

If the patient is undergoing Physical Therapy, often the Therapist will begin the session with moist heat to relax and loosen the area to be worked and after going through exercises they may apply ice briefly in closing.

But does not give a reference.

Answer 1

We ice injuries like tendinitis because they reduce the pain and inflammation. Ice does not actually fix your tendinitis, it just makes it easier to deal with. The reason it is recommended that you ice immediately after you see symptoms of tendinitis is so you can relieve the pain quicker. Icing after a few days will probably be little less effective (the tendon will have also healed a bit naturally, so the difference will be less), but if you can get rid of the pain and reduce the inflammation earlier, why wouldn't you? This is more of logic thing rather than a scientific study.

Also, if you do wait a few days before doing anything, apply heat as it will increase blood flow to the injury, allowing it to heal faster.

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^{Pain Science - Icing for Injuries, Tendinitis, and Inflammation}

^{Mayo Clinic - Which is better for relieving tendinitis pain — ice or heat? (Expert Answer)}

Answer 2

Clinical studies indicate that icing is helpful and offer symptomatic relief for tendinopathies even though the reason of its action is not yet fully understood. It is thought that ice causes vasoconstriction and address the abnormal neovascularization of the tendon tissue^{2000, PDF}.

Usually it's advised to use ice for 15–20 minutes several times a day (allowing for at least 45 minutes in between icing session), and after engaging in activities that utilize the tendon²⁰⁰⁸. However it's hard to say if ice has any long-term beneficial effect on tendinosis, but it's an excellent form of pain control (as long you won't "ice burn" from too much ice).

Icing is most effective shortly after symptoms appear in the immediate period following an injury, because it reduces the blood flow and provide temporary pain relief (similar to ice massage therapy). It can also help to reduce swelling and inflammation.

See also:

• Current Treatments for tendinosis (ISTS 2012) at Tendinosis
• How To Ice An Injury
• Tendinopathy: Why the Difference Between Tendinitis and Tendinosis Matters