Factors Involved in Recovery Times For Soft Tissue Injuries

A common question we hear at the Muscle Clinic is “How long will it take to recover from my injury ?” Managing recovery expectations is an important but difficult part of what we do as therapists and predicting recovery times, even providing ballpark figures, is not straightforward. As long as the patient is aware of the limitations it is OK to give general guidance on recovery times but if a formal prognosis is required they should be referred to a doctor.

In this blog I aim to discuss the main factors involved in recovery times for soft tissue injuries and in the next we will look at possible reasons why the recovery might be taking longer than expected.

The major recovery time factors are:

• Cause of injury, location and tissues involved
• Grade of injury
• Age
• General health and medication
• First aid and remedial treatment

Recent evidence suggests that the cause of an injury can affect healing time.

Compare running at high speed with overstretching – both can cause apparently similar soft tissue injuries at the same anatomical location, the hamstring for example, but have very different healing times. In this instance the overstretching injury can take much longer to heal.

The location of an injury makes a big difference to the healing time. Chest wall muscles involved in breathing and neck muscles involved in sustaining postural stability and controlling head movements, take longer to heal as they have little time to rest.

Different tissues regenerate at different rates. As a rule of thumb, the greater the blood supply to the tissue the quicker the recovery time. So muscle heals quicker than tendon and tendon heals quicker than ligament. It’s even been said that breaking a bone is preferred to spraining a ligament as ligaments have a very poor blood supply and can take some time to heal.

Grade of injury

Injuries are normally graded from one to three.

Grade 1 involves a tear of only a few tissue fibres with minor swelling and discomfort accompanied with a minimal loss of strength or range of movement.

Grade 2 involves greater damage with a substantial loss of strength and movement. These injuries are often the most painful and as you would expect there is a correlation between the volume of tissue injured and rehabilitation time.

Grade 3 occurs when a tear extends across the entire cross-section and completely ruptures the tissue. This can be a disturbing sight as the muscle bunches up at one end towards the joint. Interestingly the pain from a grade 3 can be less as the muscle cannot contract and put strain on the injury.

Age

There is little doubt that aging negatively affects the recovery process and is responsible for an overall reduction in muscle mass (sarcopenia) but why should this be the case? I have heard the old car analogy used to explain this. Old cars get rusty and worn out and so do we. However this doesn’t explain why, as recent research has shown, transplanted muscle heals at the rate associated with the age of the recipient and not the donor. Other experiments have demonstrated that, when a younger animal shares its circulation with an older animal, this creates a reversal in the decline of regenerative capacity. Perhaps vampires had it right all along!

Recent studies suggest that oxytocin may be one of the secret ingredients in blood that promotes regeneration of muscle tissue. Dubbed the love hormone by the press due to its effects in modulating social behaviour including bonding between couples, creating trust and stress reduction. Oxytocin has been found to activate a cellular cascade that triggers growth and proliferation of tissue and is produced in lower quantities as we age.

However, until a safe and effective treatment has been developed to reduce the negative impact of aging we will have to include advancing years as a factor in calculating the recovery time for injuries.

General health and medication

A patient with generally poor health may expect a slower recovery time. Chronic illness will put added strain on the body and often the medication will exacerbate the problem. The use of anticoagulants and immunosuppressants, such as corticosteroids have been shown to inhibit the body’s repair process. The use of NSAIDS such as Ibuprofen have also been linked to slowed recovery times for soft tissue injuries There is a strong correlation between increased healing time and smoking, obesity and alcoholism. The general health of the patient is an important factor in estimating duration of recovery.

First Aid and remedial treatments

Speed of recovery might not be everything. The quality of the repair is also important and will be affected by early decisions in the remedial treatment of the injury.

Muscle healing involves two competitive processes, scar tissue formation and muscle regeneration. Scar tissue makes for a rapid repair but inhibits muscle formation. Immobilising an injury reduces scar tissue but the new muscle fibres will not be laid down in an orderly fashion, resulting in weaker muscle. A balance needs to be found, the ideal being a short period of immobilisation followed by early mobilisation. However, an exception may be made in cases of severe ankle sprains. Studies have found that people whose ankle joint was immobilised for 10 days with a short cast recovered normal ankle function more quickly than those who were treated using exercise soon after the injury occurred.

The application of ice, as an analgesic and to reduce inflammation, is the recommended first aid protocol. However, some inflammation is essential and is important for healing and protection from infection. Care is needed as over-icing may inhibit this process. Ice on its own (as opposed to alternating ice and heat) should only be used in the very early stages of an injury. Over-icing may also promote the formation of scar tissue and adhesions reducing the quality of the repair. Ice slows down the healing process and should be used sparingly.

Further Reading
Immobilisation of ankle sprains
http://www.ncbi.nlm.nih.gov/pubmed/17279044

Immobilisation of ankle sprain
http://m.ajs.sagepub.com/content/22/1/83.short

The use of ice on injured soft tissue
http://m.ajs.sagepub.com/content/32/1/251.short

Mobilisation of injured muscle
http://link.springer.com/article/10.2165/00007256-199315020-00002

Volume of injury and rehabilitation time
http://www.ajronline.org/doi/abs/10.2214/ajr.179.6.1791621

The effect of aging on skeletal-muscle recovery from exercise: possible implications for aging athletes.
http://www.ncbi.nlm.nih.gov/pubmed/18268815
http://www.mastersathlete.com.au/sidebar/strength/recovery/
http://m.livescience.com/7919-clock-turned-aging-muscles-researchers-claim.html

Aging, exercise, and muscle protein metabolism
http://m.jap.physiology.org/content/106/6/2040.full

Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration.
http://www.ncbi.nlm.nih.gov/pubmed/24915299
https://news.berkeley.edu/2014/06/10/oxytocin-helps-muscle-regeneration/
http://www.nature.com/news/young-blood-anti-ageing-mechanism-called-into-question-1.17583

Muscles Love Oxytocin: So-Called “Hug Hormone” Important In Muscle Regeneration
http://blogs.discovermagazine.com/science-sushi/2014/06/27/new-study-shows-muscles-love-oxytocin/#.VYwrTRtViko

How sex hormones promote skeletal muscle regeneration
http://www.ncbi.nlm.nih.gov/pubmed/23888432

Muscle injuries: optimising recovery
http://www.sciencedirect.com/science/article/pii/S1521694206001471

Bone vs ligament
http://www.coreconcepts.com.sg/mcr/better-to-break-a-bone-then-to-tear-a-ligament-or-tendon/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3940509/

High speed running-type or stretching-type of hamstring injuries make a difference to treatment and prognosis
http://bjsm.bmj.com/content/46/2/86.short

Classification and grading of muscle injuries: a narrative review
http://bjsm.bmj.com/content/49/5/306.full

Impact of Smoking on Fracture Healing and Risk of Complications in Limb-Threatening Open Tibia Fractures
http://journals.lww.com/jorthotrauma/Abstract/2005/03000/Impact_of_Smoking_on_Fracture_Healing_and_Risk_of.1.aspx

Hamstring injury
http://link.springer.com/article/10.2165/00007256-199723060-00005

Massage and injury prevention
http://link.springer.com/article/10.2165/00007256-200535030-00004

Compression and recovery
http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0838.1997.tb00137.x/abstract