Healing Series: Fractures
“Healing is a matter of time, but is sometimes also a matter of opportunity.”
Hippocrates (c.460–370 BCE)
The human body is a remarkable organism, that has the capacity to heal and repair tissues regularly in order to maintain the cycle of life.
While this takes places every second of every day, we really only tend to pay attention to it when healing is compromised or we have damaged tissues (ie sickness/injury) that we are focused on repairing.
In this post, we will specifically discuss the basics of bone healing and how the process of fracture repair takes place.
What is a Fracture?
And what’s the difference between a fracture and a broken bone?
A broken bone is the same thing as a fracture. Fractures occur when the force applied to a bone exceeds the strength of the bone tissue, and it subsequently fails. This is similar to any other material that has a load placed upon it that is greater than it can tolerate.
Simple undisplaced fractures are the most common type of fracture (bone is broken but is still in good alignment). Greenstick fractures tend to occur more in children, where the bone is broken on one side (similar to a green tree branch that bends and breaks, but doesn't completely snap in half when stressed). These are commonly seen in children, as the bones are more flexible. Buckle fractures are also common in children where the bone only creases or buckles under pressure without significantly disrupting the surfaces.
Avulsion fractures are another type of fracture that is common in the developing adolescent, in which a tendon or ligament pulls off a small piece of bone (usually instead of the tendon or ligament itself rupturing). This tends to happen as adolescents are growing and their bone tissue at ligament/tendon attachment sites is not quite as strong at the ligaments/tendons themselves.
In athletes, a pathological response in bone tissue is a ‘stress reaction‘ which may lead to a stress fracture.
Rather than the typical high force, high impact traumatic injury - this type of fracture usually occurs in response to overloading the bone over time with poor recovery and progressively increasing bone stress.
Often presenting as a small hairline-crack on scans, it’s common practice to treat this conservatively (without surgical intervention) using relative rest and load management.
A stress reaction or fracture is something that can usually be identified with X-Ray and Bone Scintigraphy if there is pain and other symptoms suspicious of bone overload in response to activity. MRI may be the preferred method for confirming a stress reaction as it’s more accurate and doesn’t involve high doses of ionising radiation.
Treatment for all the above fractures usually involves a cast or splint (e.g., Moon boot) and relative rest.
More complex fractures include: displaced fractures (the bone is out of position and needs realignment); open fractures (skin is broken by the fracture or injury); and comminuted fractures (the fracture is in several pieces). These more complex fractures usually require a procedure by an orthopaedic surgeon to realign and stabilise the fracture using metal plates, wires, screws/nails - or in more severe cases, a complete joint replacement may be necessary.
Less commonly, if a person already has a metal plate in their bone or an artificial joint, they may sustain a fracture at the end of the metalware or joint replacement - also known as a peri-prosthetic fracture.
Risk Factors for Fractures
Smoking is a risk factor for fracture because of it’s impact on hormone levels that influence bone density. Additionally, poor blood supply and reduced healing capability in response to smoking significantly increases risk for increased time to fracture union and increases chances of encountering complications such as fibrous union, infection and osteomyelitis.
Alcohol. >3 units/day (a unit of alcohol is equivalent to a glass of beer/285 mL, an ounce/30 mL of spirits, or a medium-sized glass of wine/120 mL)
Drinking excessive alcohol in excess can influence bone structure and mass - even for long after alcohol consumption has stopped. Alcohol consumption results in the increased release of free radicals and inflammatory biomarkers, along with other alterations to metabolic signalling that can impair tissue repair and cell function.
Healthy bone requires sufficient quantities of calcium and vitamin D, as well as sufficient amounts of vitamin C, the amino acids lysine and proline, and other micronutrients that support the structure of collagen. The human body cannot produce vitamin C or lysine on its own and consequently there is a higher probability of shortage of these critical nutrients, which can further exacerbate the stress induced by a bone fracture, as well as compromise healing. High protein intake is surprisingly not suggested to have a huge positive affect on the healing process per se but it definitely does diminish the fracture consequences and later complications.
Steroids Exposed to ≥5 mg/day of prednisolone for ≥3 month (or equivalent doses of other glucocorticoids) and NSAIDs (non steroidal anti-inflammatory drugs)
Corticosteroids/NSAIDS play a specific role on hormones that are responsible for growth and inflammation. This is why these drugs are prescribed for conditions such as COPD, IBD and Rheumatoid Arthritis. Particularly, the side effect of most steroids results in delayed/slow formation of bone tissue, poor absorption of calcium in the gastrointestinal tract, and increased loss of calcium through the urine.
This condition is underpinned by with inflammatory process and other metabolic changes that negatively impact bone density. along with this, reduced bone loading from poor activity tolerance further weakens bone tissue and increases fracture risk. People with this condition are at over twice the risk or fractures than those who don’t. Furthermore, after a fracture has occurred, the chance of that fracture going on to heal are significantly reduced.
Type 1 diabetes is linked with low bone mineral density, which increases the likelihood of bone fracturing. In type 2 Diabetes, there isn’t a clearly defined/direct link but the nature of the disease, which damages the nerves and blood vessels, can increase the risk for falls and impair healing responses to injury . In both types, regulation of the hormone insulin is impaired which is known to directly influence bone healing efficiency.
Previous Fracture While bone tissue is great at repairing itself over time, it does take a while to reach it’s full strength post-injury. Because of this, fracture sites are often weaker than the remainder of the bone (especially in the early stage of healing) and therefore exposes bone to upto 2x the risk for of future fractures of that bone. Even though fractures do tend to heal relatively quickly, it takes some time to achieve full strength at the affected area.
Healing Timelines
Complete healing or ‘union’ can be denied by either
Radiologic/Radiographic union (where the Radiograph/X-Ray imaging doesn’t show any signs of a fractures or bone separation)
or
Clinical union (where there are no signs of pain or instability at the fracture site, usually assessed by a skilled clinician with knowledge in orthopaedics)
This is why it isn’t uncommon after for a few fractures to have consecutive investigation done with medical imaging/X-Ray in addition to planned reviews with an Orthopaedic management team.
The journey from initial injury to complete bone healing take place in stages, some of which overlap to some extent.
0-1 days: Initial trauma - bleeding (haemorrhaging) and fibrin (clotting factors) are released at the fracture site along wth any soft tissue injury areas. The broken ends of bone tissues begin necrosing (bone cells die).
First 4-5 days: Early inflammatory reaction - bleeding continues but slows down, some blood vessels are reorganised to allow inflammatory markers to rush to the area and assist the healing process by laying down cells responsible for building collagen (fibroblasts) while debris and dead bone tissue is absorbed from the area by the body.
> 1 week: Early Callus formation - as swelling in the area reduces, a callus starts to form to bridge the gap between broken bone. This begins with cells/tissue that may resemble cartilage, then progresses to form a softer, woven bone. X-Ray images often show a decreased density/thinning of bony tissue at the fracture site as this softer, woven bone begins forming.
> 3 weeks: Mature Callus Formation. - the gap between the cortical/outer layer of bone begins to heal with activity in bone cells (osteoblasts/osteoclast) increasing to allow for the beginning of harder, stronger bone formation at the fracture site.
3-6 weeks: Remodelling of Callus - the harder bone formation continues to grow stronger and the gap between the broken bone ends is filled with new, stronger bone tissue on the outer surface as well as the inner (lamellar/cancellous) bone connecting and forming strong bonds.
> 6-8 weeks: Final reconstruction - the laying down of stronger, harder bone tissue continues onward after rite fracture site has closed and becomes stable . This is usually identifiable on Xray imagining as the fracture line disappears or becomes singifcnalty less prominent.
> 3 months: Ongoing bone strengthening - the healed bone tissue will continue gaining strength and become more robust as activity increases and loads placed the bone through movement and muscles pulling are further accelerated. While the fracture may be stable and less likely ot separate, heavier impact and contact sports often require progressive strengthing up until the 3+month mark to tolerate high imapct demands without a high risk for re-fracture.
Optimising Bone Health & Healing
Studies have shown that the difference in ability to achieve peak bone mass is determined ~60–80% by genetic factors, such as ethnicity, gender, and family history, with the remaining ~20–40% by environmental factors such as nutrition, exercise, habits (smoking, alcohol, and sedentary lifestyle), various diseases, and drug use.
The risk factors mentioned above include some modifiable areas as well as some non-modifiable. While avoiding smoking and alcohol consumption seem to be obvious points, they are areas that do often get overlooked as key players in the journey towards a strong rehabilitation from a broken bone.
Further to this there are many lifestyle related changes and activity modifications that can set a rehabilitation plan up for success and accelerate the rate of speed and success of fracture repair.
Ensure you’re getting enough calories. The body needs energy to repair itself, and while it’s not uncommon for those who have fractures to be very limited in their activity levels (due to immobilisation or pain) the body still needs the energy to elicit healing responses. A common pitfall seen, is the reduction in food intake to prevent or reduce weight gain from being less active, however we need to prioritise healing above all else.
Follow Orthopaedic Restrictions/Advice (who would have thought?). The importance of keeping fractures sites from displacing/moving/shifting within the body is paramount as the cells required for building bone tissue (Osteoblasts) are most active when the two ends of broken bone are compressed together in their normal anatomical position - this is why Plaster Casting, Braces, Slings and Moon Boots are foundational to of early fracture management. It’s also important to note that there are subtle differences between each bone and fracture type that determine how much/how fast they can have load/weight placed through them.
Listen to your body. If you have reached a point at which you can remove a cast or brace (as per orthopaedic instruction) but are still getting sharp pain at the fracture site, you may still have some time to go before you start adding load to the bone. Usually this gets assessed but it’s important to play it safe if you’re unsure.
Don’t let the rest of your body deteriorate. Keeping the joints around the injured area moving to prevent stiffness or further complications a very important part of optimising your healing. Not only does this assist in supplying nutrient rich blood flow to the area, but also gives a better chance at regaining full, functional movement in timely manner after the initial healing phase.
Fractures tend to become stable by the 6-8 week mark - however, the strength of that area could take 6-12 months to achieve 100% pre-injury strength. This is why it’s so important to follow a structured rehabilitation program with individually tailored exercises to get you back to the things you need/want/love to do - especially if you have high demands or sporting goals.
LIPUS Therapy (Low Intensity Pulsed Ultrasound). While Therapeutic Ultrasound is largely ineffective for most soft tissue injuries and tends to be a poor use of clinician & patient time during a treatment session, there is evidence to show increased osteoblast activity the can maximise healing. Promising research shows reduction in time tp fracture union (~18 days faster) and improvement in fracture healing speed by upto 35% in response to daily LIPUS. The response in acute surgically treated fractures is still not clear, nor is the effect on stress reaction/stress fractures..
Low-Frequency PEMF (Pulsed Electromagnetic Field). Similar to LIPUS, this is an emerging treatment modality that has been shown in a small handful of studies to enhance growth and healing factors in a range of injuries. Like LIPUS, Low Frequency PEMF has one shown to reduce healing time and accelerate time to achieving fracture union - however, the research showing strong positive effects is still developing at this stage.
In summary, there is a WHOLE LOT of information thrown around the internet and even within hospitals/ private clinics around bone health and fractures - all of which can be overwhelming to try taking on board.
If you’d like more information on any of the information above or would like a better understanding of how movement can be medicine for you, keep an eye out for more content like this or get in touch for a personalised plan of action today.