Biomechanical Syndromes in the Lower Limbs

What is a biomechanical problem?

Many conditions seen in the lower limbs are not due to trauma or injury, but as result of faulty under-lying alignment and coordination of body parts. The human body is very tolerant to imperfections of design; it will still perform, albeit with less efficiency, precision and endurance. If the physical demand of the sport or activity exceeds the body’s ability to produce, then tissue strain, fatigue, failure and pain can result. While any body is vulnerable to symptoms from misalignment, the active or sporting population is more susceptible, especially growing children. Biomechanical problems in the lumbar spine, pelvis and hip will impact on alignment, performance and comfort of all lower limb joints and muscles.

How do we examine biomechanical problems in the lower limb?

The key to managing these biomechanical/alignment problems is to possess sound knowledge of normal biomechanics so you have the necessary skill to recognise and report where biomechanical problems exist. This is not just a static analysis of body alignment or posture, but a dynamic assessment of how neighbouring body parts interact and coordinate with each other to produce movement, eg. how does tightness or weakness in the hip muscles affect leg alignment when landing from a jump?

How do we treat biomechanical problems in the lower limb?

The rule of thumb, as always, is to treat the cause not the symptoms. This is reliant on comprehensive examination. A selection of hands-on techniques can be used to restore more ideal alignment in the spine and pelvis, then a range of soft tissue techniques used to address the muscle component to the imbalance. Important to this approach is patient education to prescribe relevant exercise to train new habits of movement, including various postural, stabilising, strengthening and stretching exercises. It isn’t simple to change someone’s default postural and alignment settings; this requires perseverance and passionate supervision. Orthotics are often required to more passively promote better lower limb alignment.

What is patella tendinopathy (jumper’s knee)?

Irritation of the patella tendon, usually at the proximal end (knee cap insertion) is common in sports requiring jumping and landing, eg volleyball, basketball, football. It was previously referred to as patella “tendonitis”, implying inflammation of the tendon, but more recent research has demonstrated that the tendon is not inflamed, but structurally damaged and attempts to heal are incomplete, leaving sub-standard collagen tissue in the tendon. Restoration of hip, pelvic and foot biomechanics, as well as very controlled and skillful jumping and landing technique training can overcome such problems. Eccentric exercise routines are used to selectively strengthen the tendon, but these need supervision. Various braces can be worn to help control symptoms during sport.

What is Osgood-Schlatter Disorder?

This is the juvenile version of patella tendinopathy. At different stages of growth, different tissues have more or less vulnerability to strain. When skeletally mature (adult), the tendon is the vulnerable tissue. Before the growth plates have fused (child), the growth plate is the vulnerable tissue. This condition is much more common in males and can be quite limiting, requiring a reduction in sporting participation. The growth plate at the insertion of the patella tendon into the proximal tibia becomes inflamed. Local pain and a distinct swelling are noticed. Parents are often concerned about the lump that appears at the top of the shin. This lump may persist after cessation of symptoms. It is not dangerous and the condition is self-limiting. Attention to biomechanics, shoe wear, orthotics and training schedules usually controls symptoms.

What is iliotibial band friction syndrome (ITBFS or runner’s knee)?

This is one of the most common problems in runners, usually distance running and usually males. A sharp pain is experienced over the outside of the knee at the lower end of the femur (thigh bone) where the iliotibial band rubs back and forth over the prominence of the lateral femoral condyle. The pain often comes on suddenly at a certain stage in the run, and can be near impossible to run through. Fatigue in the muscles controlling pelvic stability is thought to be an underlying cause, resulting in over-use of the tensor fascia lata as a lateral pelvic stabiliser. Treatment involves correction of the biomechanical cause. Cortisone/local anaesthetic injections at the painful site may be a useful adjunct therapy.

What are shin splints?

“Shin splints” is another one of those diagnostic labels that describes a syndrome, not a succinct condition or cause. It is also called medial tibial stress syndrome. This refers to pain felt in the shin during physical exercise, usually the anteromedial aspect. Three main varieties exist. Accurate diagnosis is essential to effective management. There are some tell-tale clinical features, associated symptoms and behaviours that distinguish the varieties, as well as investigations that help define the cause, eg. bone scan, compartment testing. o Tenoperiosteitis. Over reliance on the posterior tibial group of muscles to control excessive pronation at the foot will cause irritation at the site where the muscle joins onto the tibial bone. Exquisite local tenderness, swelling and crepitus is often seen, and symptoms can worsen in the cool-down period after sport. o Stress fracture. This is not a break of the bone, but a remodeling of the tibial cortex in response to abnormal stresses across the bone, because of faulty biomechanics. Feet that lack shock absorption (supinators) are vulnerable. Restriction of weight-bearing training and correction of faulty biomechanics is the treatment response. Night pain is a feature of this condition. o Compartment syndrome. The muscles of the shank are all confined within membranous compartments, where there is only so much room for volume expansion with weight-training and exercise before circulation within the compartment is cut off. Deep diffuse aching pain, weakness and neurological symptoms in the foot are hallmark features. Signs and symptoms are usually only evident during sport and not after. Surgery is required to release the compartment.

What is Achilles tendinopathy?

This is a similar type pathology to patellar tendinopathy; pain and swelling is experienced where the Achilles (heel cord) inserts into the heel. It used to be referred to as Achilles tendonitis. Tendons are excellent structures for shock-absorbing when they function in straight lines (where tensile forces are parallel to the collagen fibres), but where biomechanical problems in the spine/pelvis/legs/feet cause problems such as pronation, abnormal forces are placed on the tendon, which starts to break down. This area of the Achilles tendon is a problem in terms of poor blood supply, which effects healing potential when strained. Severe, end stage tendon problems require surgery to open the tendon and remove the damaged tissue, and also to stimulate new tissue growth. Less severe cases can be managed with biomechanical correction, often including orthotics, training modification and eccentric exercise regimes.

What is Sever’s disease?

This is the juvenile form of Achilles tendinopathy. Tight calves and pronation control is often the problem, along with sporting volume. It does not require surgery.

What are plantar fasciitis, heel spurs?

The plantar fascia is a collagenous rope-like structure that runs from the under-surface of the heel, forward to the base of the big toe. It is an essential structure in supporting the stability of the arch of the foot, as well as being critical to supinating the foot during heel-off phase of walking by the windlass effect. Pain is reported deep under the heel, often bilaterally. It is often worse on initiating walking after being sedentary for a while, eg. getting out of bed. If the plantar fascia is chronically strained over a long-enough period, the ligament heals with bone rather than collagen, producing a “heel spur” on x-ray. A heel spur is a symptom not a cause of pain, so there is no point having it surgically removed. Treatment of plantar fasciitis is usually biomechanical correction + orthotics. Other approaches such as weight-loss and cortisone injections have merit.