Information Sheets

Knee Injuries in Adolescents: Incident, Prevalence and Mobility

Adolescence is a specific and unique development phase defined by growth and development. Biologically, physically, cognitively, psychologically and socially, growth is more rapid during this stage than any other growth period, excluding infancy. A large number of sporting injuries occur in adolescents, with sport and physical activity being the leasing cause of injury related visits to pediatric emergency departments in the United States. Both the incidence and severity of sports related injuries increase during the period of adolescence comparative to that of childhood. A recent one-year prospective study found that, at baseline, as many as 53% of pre-teens and early adolescents have experienced muscular skeletal pain at some point during their lives, with 21% of those who were pain free at baseline. There is a high risk of sporting injury and muscular skeletal pain in the adolescent population with the knee appearing to be particularly susceptible to injury. 

It is during adolescence that gender differences begin to emerge in injury profiles related to sport and physical activity. As age increases, there appears to be a greater difference in injury rate and profile between genders. The gender bias in injuries is frequently described at the knee. While males have a higher overall rate of knee injury females have a higher rate of major knee injury and are twice as likely to sustain a major non-contact knee injury. It has been reported that female adolescents have a four to six times higher rate of non-contact ACL injury compared to male adolescents. Literature regarding PFPS in the knee recorded that adolescent females are at double the risk of adolescent males with an overall rate of 21-45%. 

Knee injuries sustained during adolescents may have long-term implications. There is evidence that suggests patellofemoral pain syndrome (PFPS) may become chronic, with one in four adolescent females who still had pain at 4 years continuing up to 20 years after their initial presentation. An additional long term impact of knee injury is the potential impact on physical activity. During adolescence females statistically many females become less active, pain and injury are among a number of factors that may contribute to the decline in participation in physical activity and exercise. The government recommends 60 minutes of moderate exercise per day, including at least 20 minuets of vigorous activity 4 times per week. It is extremely important for adolescent females to participate in vigorous activity as higher intensity weight bearing exercise appears to be most beneficial for promoting bone mass and prevention of osteoporosis later in life. Adolescence appears to be the critical time to maximize bone mass in females. Inability to meet the government guidelines for physical activity may have long-term implications for the health of female adolescents and the wider community. It is essential to understand the why female adolescence are at a greater risk , in order to develop and implement correct prevention and management strategies.

Minimal Shoe and Barefoot Running

Harvard professor Dan Lieberman is an evolutionary biologist best known for his theories about barefoot running. He states that out of the one million people that will run a marathon next year and of those that run for either recreational or exercise purposes, a large proportion (between 20-90% of these individuals) will develop repetitive stress injuries from running. Lieberman’s background in evolutionary biology has lead him to the hypothesis that ‘some of the running injuries that people get … come from a mismatch between the way we use our bodies and the way our bodies are adapted’. Anatomically Lieberman states that humans are ‘loaded…with special features…some of them important for walking but some important for running, for example our long Achilles tendon…or the gluteus Maximus…’ a significant point he raises is the ‘importance of proprioception’ referring to the sensory information that humans receive from bare feet, allowing for quick reaction to changes in terrain or substrate, as he states ‘even putting a sock on somebody’s foot decreases your dynamic stability considerably. So we’re much more stable when barefoot’.  

One of the basic findings in Lieberman’s research is that while habitual barefoot runners strike with the mid-foot, most shod runners, heel strike. Lieberman highlights that the heel striking action causes a ‘rapid exchange of momentum between your body and the ground. This causes a collision peak, called and impact peak and if you were barefoot, that force can rise between one and two-and-a-half times your body mass.’ He states that heel striking does have its benefits including, a reduced requirement of calf strength, and allows runners to over stride which is an easier way of going faster, however his research has shown that barefoot forefoot strikers have increased compliance in their legs, and a decreased loading rate, he also believes that there is a possibility that forefront striking leads to better performance, as he commented ‘I don’t know if there’s a single distance record held in any event by a heel striker.’

Lieberman suggests that whatever the running style there are two important principals that good runners have in common. The first is that they lean forward. The second is they have a high stride frequency. Lieberman acknowledges the fundamental importance of understanding how running form relates to injury. Meta-analyses, injury rates fluctuate between 20-90 percent, Lieberman states that, ‘there’s no decline in running injury rates over the last 30,40 years…and that’s the problem. Somehow, the methods we’re using to try and treat…and prevent running injuries, somehow don’t seem to be working effectively.’ He added that there is no evidence to support that prescription shoes reduce injury rates. Lieberman reiterates his opinion that the reduction of running injuries relies far more on form than footwear. 

Studies by colleague Irene Davis have lead to suggest that the rate and active loading impact peaks may have a significant influence on injury however this is dispute by other researches and continues to be debated. Leiberman states that whilst barefoot forefoot striking may reduce incidence of back pain, stress fractures, shin splints and other injuries, its striking increases loading on the Achilles which could lead to higher rates of some tendonopathies. Lieberman belief is that, ‘Its all about form. It’s a skill.’ Thus regardless of footwear, correct technique when running is essential for the prevention of running relate injuries.

Load Monitoring for Rugby Union Players

The primary purpose of athlete load monitoring is to maximize sporting performance and minimize the risk of injury (or lost training days). 
In order to achieve this, you need to ensure that you are:

  1. collecting/recording the information regularly and consistently to ensure reliability
  2. verify it is practical to obtain (ie, if you are travelling and/or in hotels etc.) 
  3. analyze information at the time of collection
  4. interpret the results against agreed team specific standards
  5. discuss the results with the relevant medical staff, coaches and athletes
  6. effect immediate change to the planned training sessions for that day/week
  7. assess and review their effectiveness at achieving your agreed goals

Daily Measures

GPS and heart rate monitoring
GPS units have been used since 2010 to quantify athletes training load and performance such as, training time, distance ran, speeds produced and number of acceleration/de-acceleration/agility movements.
The data is collected and modified for the purposes of (1) determining what the athletes actually do in a test match/Super 15 game, (2) modify our planned training loads to ensure athletes are training at levels required for games, (3) monitoring how athletes are coping with training/playing loads, and (4) prepare a ‘return to sport’ rehabilitation program for all injured athletes. 

Training Sessions
All training sessions are recorded and coded for athletes to review their position, role play/patterns and skill execution on laptops at their leisure. This includes all the skill components of lineout’s, scrimmaging and goal kicking. 

Physiotherapy Treatment 
This is available daily for athletes. 
Medical Meetings and Reviews
The medical team (sports physician and physiotherapists) and conditioning coach meet two to three times per day to discuss the individual training status of athletes. This is typically before the morning training session, after the training session (for any modifications to the afternoon’s weights sessions) and at the end of the day, post-afternoon physiotherapy treatment.

Weekly Measures

Medical Screening and Online Injury Prevention System 
The Injury Prevention System (IPS) is completed every Monday morning. It takes about 10 minuets to complete, and asks a series of questions about the athlete’s physical measures, football played, any injuries sustained and a series of subjective self-rating scales. Every athlete is then required to meet with the team sports physician to discuss their results and assess any injury the may have with the view of determining their training status for Monday. 

Physiotherapy review and rehabilitation programs 
Each athlete sees one or two physiotherapists, they each have an individual written ongoing rehabilitation program. That covers their current acute injuries and/or injury history profiles. Weekly strength dynamometer testing on various athletes to monitor muscular skeletal recovery from weekend games and weekly training loads. 

Specific flexibility and rehabilitation group sessions 
Each week compulsory flexibility/stretch sessions (twice per week) for the front row and forwards, and rehabilitation sessions (twice per week) for those athletes who need to spend additional time mastering and progressing their individual rehabilitation. The ‘Front row flexibility’ session is specifically directed at ensuring each of these athletes has the ability to reach and maintain the required ‘scrumming position. The athletes perform a series of join mobilizations (lower back, ankle), stretches(lower back, psoas, gluts, and hamstring) and neural glides (lower limb) for approximately 20-30minutes. The ‘rehabilitation’ session involves approximately four to eight athletes who are either new and relatively young in terms of playing years, are returning from long-term injuries or simply prefer to be challenged in a group environment. 

Measures Completed at Regular Intervals Throughout the Season 

Monitoring injured athletes not with the team
Given the nature of the demanding season any athletes that sustain significant injuries return home to their franchise state to complete their rehabilitation, until they are declared fit to train or are available for selection. This involves a coordinated approach between the conditioning coaches and medical teams of both the wallabies and franchises. The search for the balance between training load, training effect, and athletic performance, contributing factors is a constantly evolving equilibrium. 

Optimising Bike Set-up

Optimising bike set-up will maximize cycling performance and minimize overuse injuries. In cycling the interaction between the athletes body and the sporting equipment used is highly complex. This interaction is influenced by the cyclists anthropometric measurements, their flexibility, cycle specific strength and even neural mobility. Optimising the riding position within the comfort range of the cyclists biomechanical limitations therefore becomes very important to not only minimize injuries but also to optimize performance.

Physiotherapists have the unique skills to perform a detailed musculoskeletal screening to asses spinal/neural mobility, hip and lower limb mobility and muscular strength prior to adjusting bike set-up.

Ideal seat height: when doing cycling biomechanical set-ups in the clinic, the ideal set height is determined using the following equation:
0.98 x (lower limb leg length + cleat thickness)

Lower limb leg length is the height of the highest point of the greater trochanter to the floor. This is measured vertically with a tape measure without shoes, and the feet approximately pedal width apart with symmetrical weight bearing.

Cleat thickness: can vary significantly from 10 to 40mms. In the typical road cycling shoe, this should be measured with a tape measure without shoes and added to the leg length measurement.

If the athlete is/has been used to a lower seat height, it is best to not raise the seat above 0.96 x (lower leg limb + cleat thickness). This will allow the athlete to gradually get used to the longer hamstring and calf length.

If the athlete is/has been used to a seat height well above the ideal, the seat must be brought down to the ideal seat height measurement of 0.98 x (lower leg limb length + cleat thickness).

Once the seat height for the individual athlete has been decided on, the seat itself can be moved forwards or backwards to minimize forces at the knee and reach to handlebars.

Rugby League: A Sports Physiotherapists Point of View

Efficient injury treatment, injury prevention strategies, and implementation of systems aimed at performance enhancement are the core goals of the physiotherapist. The physiotherapist has an important role in conducting and analyzing musculoskeletal screening procedures.

Contact Injuries: these are more likely to force players out of competition for prolonged periods. The more common contact injuries include muscle contusion, glenhumeral instability, acromioclaviculr joint sprain/dislocation, sternal contusion, brachial neuropraxia, knee and ankle alignment injury, concussion, cervical spine injury, and jaw fracture. Evidence has suggested that a higher number of contact injuries occur at the beginning or end of the season, rather than in the middle. This can be attributed to poor timing in high-speed contact situations, which is the result of a lack of ‘game specific speed’ practice during pre-season contact drills. Contact injuries at the end of the season can be attributed to a mental and/or physical fatigue of the player.

Non-Contact Injuries: these mostly include muscle strains, bone stress conditions and numerous other overuse injuries affecting soft tissues of the lower limb. Most common sites of injury are the groin, lower leg, and posterior thigh musculature. Many of these injuries can be attributed to an increase in load with an insufficient recovery period prior to the next significant load and so on. Well performed, technical lifting is a vital tool to use in treating these problems efficiently. Consistent technical feedback is required to avoid lumbar injury, especially when dealing with developing athletes.

Regular screening to detect soft tissue restriction ‘early’ can be a very useful injury prevention tool. In summary, decreasing injury levels will improve the performance of the team. This is the overall goal of the medical staff. 

OA Highlights

OA can severely curtail the activities of recreational sports persons.
It has been reported that the most widespread treatments for OA include paracetamol, NSIADS, steroid injection, hyaluronic injection, and surgery. Intersetingly, the effects of these interventions are dwarfed by weight loss, exercise and braces/orthoses by a factor if three. A 5 percent weight loss makes a massive difference. Even a single kilogram is significant.

Research shows that if knee joint stability is compromised (i.e. ACL injury, ACL reconstruction, AMP), the medial/lateral movement of the joint is increased. There is also an increased tibial rotation. Both will significantly increase the stress through the knee. Following ACL reconstruction, the quadriceps are often residually weak/range of motion is often difficult to regain. This alters gait patterns and changes the loading through the knee, and can effect the process of degeneration.

OA typically have a high level of co-contraction of muscles around the knee which increase total joint compression and the stress around it. A loss of range of motion means stress load through the joint is over a smaller area of articular cartilage.

So is OA a consequence of exercise or injury? Running less than 25km/week is suggested to be beneficial to articular cartilage. Heavy work such as kneeling or repetitive squatting or jumping results in a higher incidence of knee OA.

Risk factors for sports persons developing OA include previous knee injury and high BMI AT 20 years of age. Returning to cutting sports after a significant knee injury and surgery can increase the risk of developing OA, and need to be evaluated on how to minimize the risk.

Thoracic Spine

A stiff thoracic spine is a primarily contributing factor for all chronic spinal pain.

If you look at the facet joints of the thoracic spine, you will realize that the facets are organized in the frontal plane and the main movement allowed is rotation; in the lumbar spine the facets are sagittal, and the main movement is flexion/extension and there is hardly any rotation.

If you lose thoracic rotation, two things happen; first, you get a stiff thoracic spine that won’t extend, throwing your head into a forward head posture and giving you a sore neck; and second, you have to twist more in the lower back or pelvis to do things and you hurt your back by over rotating it in flexion.

Restoring thoracic mobility helps help’s neck and low back pain. There are even high-quality randomized trials that prove that thoracic manipulation is as effective for neck pain as neck manipulation.

It is sometimes better to teach patients to change their bad habits: maintain a good upright sitting posture and do daily exercise to maintain thoracic mobility.

Thus, Active thoracic extension, scapular exercises, spinal hygiene and avoidance of high repetitive loads while the spine is growing are used as key preventative strategies.

Sporting Injuries

Injury to an athlete may be considered to be either an acute or overuse injury.

In acute injuries, a force occurs suddenly to a normal tissue, and at the time of injury exceeds the strength of the structure which results in damage.

Force are normally muscle contractions leading to muscle or tendon tears, twisting injuries as in ankle sprains and knee ligament injuries and direct trauma or contusion from impact with an opponent or object.

First aid treatment involving RICE should be given as soon as possible, to minimise bleeding.  An early accurate diagnosis of the tissue injured is essential to direct the optimal treatment pathway.

Treatment may involve surgery or conservative management with a sports professional guiding the injured athlete through a well-designed graded rehabilitation programme.

An overuse injury is from repetitive activity such as running or fast bowling in cricket.  Repetition leads to microtrauma which overloads the capacity of the tissue to repair itself.

The most common overuse injuries affect tendons as in tendinosis and bone as in stress fractures.

The cause of overuse injuries is most often multifactorial involving intrinsic and extrinsic factors such as training errors and poor biomechanics.

The greatest challenge is to identify and correct the causes.

Knee Instability

True knee instability occurs when the joint translates out of its ligamentous and muscular boundaries and the articular surface partially or totally disengages.

Patients state the knee gives way and feel exactly what happens as the knee subluxes or dislocates.

There is another type of giving way which occurs in knees which are ligamentously stable.

Knee pain from a torn meniscus for example an inhibit the quadriceps which causes the knee to bend and give way.

Anterior cruciate ligament injuries are the most common instability seen in the knee.

The history of injury usually involves a twisting injury as in a side stepping, cutting, jumping or landing force which is associated with a snap, pop or crack and collapse of the knee.

Acromioclavicular Joint Injuries

Acromioclavicular or AC joint injuries are one of the most common injuries of the upper limb and are ten times more common than glenohumeral joint dislocations.

The injury may be a sprain, a partial dislocation or complete dislocation.  Acromioclavicular joint injury is often seen in men who fall onto the shoulder in contact or collision sports.

Management of the acute injury includes exclusion of other associated injuries including the cervical spine or brachial plexus.

Acromioclavicular injures are common and for the most part do not require operative treatment.

Fast Bowling Injuries in Cricket

Playing cricket is associated with a various range of acute and overuse injuries.

Studies have reported an incidence of injury in bowlers of 42%, fielders 41% and batsman 17%.  A study in Australian first-class cricketers reported a prevalence of 14% for pace bowlers and 4% for spin bowlers.  The most common injuries were lumbar injuries, side strains, hamstring and groin injuries.

Fast Bowling is widely considered as a non-contact sport with a high risk of injury.  There is a load threshold above and below which injury is more likely to occur. 

The other significant factor in fast bowling overuse injuries is technique.  The use of a mixed technique rather than front or side on is strongly implicated in spinal injuries.

Exercise and Osteoarthritis

The relationship between exercise and arthritis has always been one of public interest.  Exercise is beneficial to joints because it increases the circulation of synovial fluid which bathe the articular cartilage with nutrients.

The exact amount of exercise that would benefit and not be destructive to joints is difficult to determine.

Studies indicate that certain activities such as competitive high impact running and occupations which require deep knee bending and lifting before the age of 50 years may be associated with an increased risk of hip osteoarthritis.

Recreational jogging for individuals of 60 or more years of age with normal knee and hip joints does not increase the risk of developing osteoarthritis.

Optimal management for osteoarthritis will involve preventing the loss of joint space by engaging life style changes to decrease loading and maintain joint range of motion.

Early signs of osteoarthritis respond well to aerobic exercise.