Because wear on the hip joint traces to the structures that support it (the posture of the legs, and ultimately, the feet), proper fitting shoes with adequate support are important to preventing GTPS. For someone who has flat feet, wearing proper orthotic inserts and replacing them as often as recommended are also important preventive measures.

Strength in the core and legs is also important to posture, so physical training also helps to prevent GTPS. But it is equally important to avoid exercises that damage the hip.

The cause of snapping hip syndrome is not well understood, and confusion exists within the medical community regarding causation. Athletes appear to be at an enhanced risk for snapping hip syndrome due to repetitive and physically demanding movements.

In athletes such as ballet dancers, gymnasts, horse riders, track and field athletes and soccer players, military training, or any vigorous exerciser, repeated hip flexion leads to injury. In excessive weightlifting or running, the cause is usually attributed to extreme thickening of the tendons in the hip region. Snapping hip syndrome most often occurs in people who are 15 to 40 years old.

The condition is usually self-limiting and is caused by stress on the patellar tendon that attaches the quadriceps muscle at the front of the thigh to the tibial tuberosity. Following an adolescent growth spurt, repeated stress from contraction of the quadriceps is transmitted through the patellar tendon to the immature tibial tuberosity. This can cause multiple subacute avulsion fractures along with inflammation of the tendon, leading to excess bone growth in the tuberosity and producing a visible lump which can be very painful, especially when hit. Activities such as kneeling may also irritate the tendon.

The syndrome may develop without trauma or other apparent cause; however, some studies report up to 50% of patients relate a history of precipitating trauma. Several authors have tried to identify the actual underlying etiology and risk factors that predispose Osgood–Schlatter disease and postulated various theories. However, currently it is widely accepted that Osgood–Schlatter disease is a traction apophysitis of the proximal tibial tubercle at the insertion of the patellar tendon caused by repetitive micro-trauma. In other

words, Osgood–Schlatter disease is an overuse injury and closely related to the physical activity of the child. It was shown that children

who actively participate in sports are affected more frequently as compared with non-participants. In a retrospective study of adolescents, old athletes actively participating in sports showed a frequency of 21% reporting the syndrome compared with only 4.5% of age-matched nonathletic controls.

The symptoms usually resolve with treatment but may recur for 12–24 months before complete resolution at skeletal maturity, when the tibial epiphysis fuses. In some cases the symptoms do not resolve until the patient is fully grown. In approximately 10% of patients the symptoms continue unabated into adulthood, despite all conservative measures.

The cause of trigger finger is unclear but several causes have been proposed. It has also been called stenosing tenosynovitis (specifically "digital tenosynovitis stenosans"), but this may be a misnomer, as inflammation is not a predominant feature.

It has been speculated that repetitive forceful use of a digit leads to narrowing of the fibrous digital sheath in which it runs, but there is little scientific data to support this theory. The relationship of trigger finger to work activities is debatable and scientific evidence for and against hand use as a cause exist. While the mechanism is unclear, there is some evidence that triggering of the thumb is more likely to occur following surgery for carpal tunnel syndrome. It may also occur in rheumatoid arthritis.

OSD occurs from the combined effects of tibial tuberosity immaturity and quadriceps tightness. There is a possibility of migration of the ossicle or fragmentation in Osgood-Schlatter patients. The implications of OSD and the ossification of the tubercle can lead to functional limitations and pain for patients into adulthood.

Of people admitted with OSD, about half were children who were between the ages of 1 and 17. In addition, in 2014, a case study of 261 patients was observed over 12 to 24 months. 237 of these people responded well to sport restriction and non-steroid anti-inflammatory agents, which resulted in recovery to normal athletic activity.

Extra-articular snapping hip syndrome is commonly associated with leg length difference (usually the long side is symptomatic), tightness in the iliotibial band (ITB) on the involved side, weakness in hip abductors and external rotators, poor lumbopelvic stability and abnormal foot mechanics (overpronation). Popping occurs when the thickened posterior aspect of the ITB or the anterior gluteus maximus rubs over the greater trochanter as the hip is extended.

The most common examples of this condition:

- Prepatellar bursitis, "housemaid's knee"

- Infrapatellar bursitis, "clergyman's knee"

- Trochanteric bursitis, giving pain over lateral aspect of hip

- Olecranon bursitis, "student's elbow", characterised by pain and swelling in the elbow

- Subacromial bursitis, giving shoulder pain, is the most common form of bursitis.

- Achilles bursitis

- Retrocalcaneal bursitis

- Ischial bursitis, "weaver's bottom"

- Iliopsoas bursitis

- Anserine bursitis

There can be several concurrent causes. Trauma, auto-immune disorders, infection and iatrogenic (medicine-related) factors can all cause bursitis. Bursitis is commonly caused by repetitive movement and excessive pressure. Shoulders, elbows and knees are the most commonly affected. Inflammation of the bursae may also be caused by other inflammatory conditions such as rheumatoid arthritis, scleroderma, systemic lupus erythematosus and gout. Immune deficiencies, including HIV and diabetes, can also cause bursitis. Infrequently, scoliosis can cause bursitis of the shoulders; however, shoulder bursitis is more commonly caused by overuse of the shoulder joint and related muscles.

Traumatic injury is another cause of bursitis. The inflammation irritates because the bursa no longer fits in the original small area between the bone and the functionary muscle or tendon. When the bone increases pressure upon the bursa, bursitis results. Sometimes the cause is unknown. It can also be associated with various other chronic systemic diseases.

In 1997 Morrison et al.

published a study that reviewed the cases of 616 patients (636 shoulders) with impingement syndrome (painful arc of motion) to assess the outcome of non-surgical care. An attempt was made to exclude patients who were suspected of having additional shoulder conditions such as, full-thickness tears of the rotator cuff, degenerative arthritis of the acromioclavicular joint, instability of the glenohumeral joint, or adhesive capsulitis. All patients were managed with anti-inflammatory medication and a specific, supervised physical-therapy regimen. The patients were followed up from six months to over six years. They found that 67% (413 patients) of the patients improved, while 28% did not improve and went to surgical treatment. 5% did not improve and declined further treatment.

Of the 413 patients who improved, 74 had a recurrence of symptoms during the observation period and their symptoms responded to rest or after resumption of the exercise program.

The Morrison study shows that the outcome of impingement symptoms varies with patient characteristics. Younger patients ( 20 years or less) and patients between 41 and 60 years of age, fared better than those who were in the 21 to 40 years age group. This may be related to the peak incidence of work, job requirements, sports and hobby related activities, that may place greater demands on the shoulder. However, patients who were older than sixty years of age had the "poorest results". It is known that the rotator cuff and adjacent structures undergo degenerative changes with ageing.

The authors were unable to posit an explanation for the observation of the bimodal distribution of satisfactory results with regard to age. They concluded that it was "unclear why (those) who were twenty-one to forty years old had less satisfactory results". The poorer outcome for patients over 60 years old was thought to be potentially related to "undiagnosed full-thickness tears of the rotator cuff".

Accidental or deliberate physical trauma may result in either a fracture, muscle bruising, or a contusion. It is the leading cause of a limp. Deliberate abuse is important to consider.

Greater trochanteric pain syndrome (GTPS), also known as trochanteric bursitis, is inflammation of the trochanteric bursa, a part of the hip.

This bursa is at the top, outer side of the femur, between the insertion of the gluteus medius and gluteus minimus muscles into the greater trochanter of the femur and the femoral shaft. It has the function, in common with other bursae, of working as a shock absorber and as a lubricant for the movement of the muscles adjacent to it.

Occasionally, this bursa can become inflamed and clinically painful and tender. This condition can be a manifestation of an injury (often resulting from a twisting motion or from overuse), but sometimes arises for no obviously definable cause. The symptoms are pain in the hip region on walking, and tenderness over the upper part of the femur, which may result in the inability to lie in comfort on the affected side.

More often the lateral hip pain is caused by disease of the gluteal tendons that secondarily inflames the bursa. This is most common in middle-aged women and is associated with a chronic and debilitating pain which does not respond to conservative treatment. Other causes of trochanteric bursitis include uneven leg length, iliotibial band syndrome, and weakness of the hip abductor muscles.

Greater trochanteric pain syndrome can remain incorrectly diagnosed for years, because it shares the same pattern of pain with many other musculoskeletal conditions. Thus people with this condition may be labeled malingerers, or may undergo many ineffective treatments due to misdiagnosis. It may also coexist with low back pain, arthritis, and obesity.

The literature on the pathophysiology of bursitis describes inflammation as the primary cause of symptoms. Inflammatory bursitis is usually the result of repetitive injury to the bursa.

In the subacromial bursa, this generally occurs due to microtrauma to adjacent structures, particularly the supraspinatus tendon. The inflammatory process causes synovial cells to multiply, increasing collagen formation and fluid production within the bursa and reduction in the outside layer of lubrication (Ishii et al., 1997).

Less frequently observed causes of subacromial bursitis include hemorrhagic conditions, crystal deposition and infection.

Many causes have been proposed in the medical literature for subacromial impingement syndrome. The bursa facilitates the motion of the rotator cuff beneath the arch, any disturbance of the relationship of the subacromial structures can lead to impingement. These factors can be broadly classified as intrinsic such as tendon degeneration, rotator cuff muscle weakness and overuse. Extrinsic factors include bone spurs from the acromion or AC joint, shoulder instability and neurologic problems arising outside of the shoulder.

Anything compromising the tunnel of the posterior tibial nerve proves significant in the risk of causing TTS. Neuropathy can occur in the lower limb through many modalities, some of which include obesity and inflammation around the joints. By association, this includes risk factors such as RA, compressed shoes, pregnancy, diabetes and thyroid diseases

In most people, ligaments (which are the tissues that connect bones to each other) are naturally tight in such a way that the joints are restricted to 'normal' ranges of motion. This creates normal joint stability. If muscular control does not compensate for ligamentous laxity, joint instability may result. The trait is almost certainly hereditary, and is usually something the affected person would just be aware of, rather than a serious medical condition. However, if there is widespread laxity of other connective tissue, then this may be a sign of Ehlers-Danlos syndrome.

Ligamentous laxity may also result from injury, such as from a vehicle accident. It can result from whiplash and be overlooked for years by doctors who are not looking for it, despite the chronic pain that accompanies the resultant spinal instability. Ligamentous laxity will show up on an upright magnetic resonance imaging (MRI), the only kind of MRI that will show soft tissue damage. It can be seen in standing stress radiographs in flexion, extension, and neutral views as well, and also digital motion X-ray, or DMX.

An advantage to having lax ligaments and joints is the ability to withstand pain from hyperextension; however, this is also a disadvantage as a lack of perceived pain can prevent a person from removing the ligament from insult, leading to ligament damage. This can also lead to death if you tear the wrong ligament. People with hypermobile joints (or "double-jointed" people), almost by definition, have lax ligaments.

Though TTS is rare, its cause can be determined in 70% of reported cases. In the workplace TTS is considered a musculoskeletal disorder and accounts for 1.8 million cases a year, which accumulates to about $15–$20 billion a year New studies indicate an occurrence of TTS in sports placing high loads on the ankle joint (3). This can be seen in figure 1. TTS occurs more dominantly in active adults, with a higher pervasiveness among women. Active adults that experience more jumping and landing on the ankle joint are more susceptible (see figure 2). Though athletics and sport are correlations, cases are individualistically assessed because of the oddity.

Other infections that classically lead to a limp include Lyme disease (a bacterial infection spread by a deer tick) and osteomyelitis (an infection of the bone).

Trigger fingers is a common disorder characterized by catching, snapping or locking of the involved finger flexor tendon, associated with dysfunction and pain. It is a sub-set of stenosing tenosynovitis.

A disparity in size between the flexor tendon and the surrounding retinacular pulley system, most commonly at the level of the first annular (A1) pulley, results in difficulty flexing or extending the finger and the "triggering" phenomenon. The label of trigger finger is used because when the finger unlocks, it pops back suddenly, as if releasing a trigger on a gun.

Those who have loose ligaments in the legs and feet often mistakenly assume that they have flat feet. While their feet have an arch when not supporting weight, when stood upon, the arch will flatten. This is because the loose ligaments cannot support the arch in the way that they should. This can make walking and standing painful and tiring.

Pain will usually occur in the feet and lower legs, but can also spread to the back due to abnormal standing and walking habits. Wearing shoes that have good arch support can help minimize the discomfort. The underlying problem, however, is not solved by wearing shoes with arch supports or worsened by wearing shoes without arch support. There is currently no cure for the condition.

In addition, people with ligamentous laxity often have clumsy or deliberate gaits, owing to the body having to overcompensate for the greater amount of energy required to offset the weakened ligaments. The feet may be spread apart at a wide angle, and the knees may flex backwards slightly after each stride.

Those who have this disease may experience sprained ankles more frequently than other people.

Distal radius fractures are the most common fractures seen in adults, with incidence in females outnumbering incidence in males by a factor of 2-3. Men who sustain distal radius fractures are usually younger, generally in their fifth decade (vs. seventh decade in females). The elderly are more susceptible because of the osteopenia and osteoporosis commonly seen in this age group. The majority of these fractures are extra-articular (i.e. not involving the joint).

This is also a common injury in children which may involve the growth plate (Salter-Harris fracture).

In young adults, the injury is often severe as a greater force is necessary to produce the injury.

In medicine, an enthesopathy refers to a disorder involving the attachment of a tendon or ligament to a bone. This site of attachment is known as the entheses.

If the condition is known to be inflammatory, it can more precisely be called an enthesitis.

Enthesopathies may take the form of spondyloarthropathies (joint diseases of the spine) such as ankylosing spondylitis, plantar fasciitis, and Achilles tendinitis. Enthesopathy can occur at the elbow, wrist, carpus, hip, knee, ankle, tarsus, or heel bone, among other regions. Further examples include:

- Adhesive capsulitis of shoulder

- Rotator cuff syndrome of shoulder and allied disorders

- Periarthritis of shoulder

- Scapulohumeral fibrositis

- Synovitis of hand or wrist

- Periarthritis of wrist

- Gluteal tendinitis

- Iliac crest spur

- Psoas tendinitis

- Trochanteric tendinitis

TMD does not obviously run in families like a genetic disease. It has been suggested that a genetic predisposition for developing TMD (and chronic pain syndromes generally) could exist. This has been postulated to be explained by variations of the gene which codes for the enzyme catechol-O-methyl transferase (COMT) which may produce 3 different phenotypes with regards pain sensitivity. COMT (together with monoamine oxidase) is involved in breaking down catecholamines (e.g. dopamine, epinephrine, and norepinephrine). The variation of the COMT gene which produces less of this enzyme is associated with a high sensitivity to pain. Females with this variation, are at 2–3 times greater risk of developing TMD than females without this variant. However this theory is controversial since there is conflicting evidence.

Occlusal factors as an etiologic factor in TMD is a controversial topic. Abnormalities of occlusion (problems with the bite) are often blamed for TMD but there is no evidence that these factors are involved. Occlusal abnormalities are incredibly common, and most people with occlusal abnormalities do not have TMD. Although occlusal features may affect observed electrical activity in masticatory muscles, there are no statistically significant differences in the number of occlusal abnormalities in people with TMD and in people without TMD. There is also no evidence for a causal link between orthodontic treatment and TMD. The modern, mainstream view is that the vast majority of people with TMD, occlusal factors are not related. Theories of occlusal factors in TMD are largely of historical interest. A causal relationship between occlusal factors and TMD was championed by Ramfjord in the 1960s. A small minority of dentists continue to prescribe occlusal adjustments in the belief that this will prevent or treat TMD despite the existence of systematic reviews of the subject which state that there is no evidence for such practices, and the vast majority of opinion being that no irreversible treatment should be carried out in TMD (see Occlusal adjustment).

Increased risk of developing knee and hip osteoarthritis was found in those who:

- work with manual handling (e.g. lifting)

- have physically demanding work

- walk at work

- have climbing tasks at work (e.g. climb stairs or ladders)

Increased risk of developing hip osteoarthritis over time was found among those who work in bent or twisted positions.

Increased risk of knee osteoarthritis was found in those who:

- work in a kneeling or squatting position

- experience heavy lifting in combination with a kneeling or squatting posture

- work standing up

A number of studies have shown that there is a greater prevalence of the disease among siblings and especially identical twins, indicating a hereditary basis. Although a single factor is not generally sufficient to cause the disease, about half of the variation in susceptibility has been assigned to genetic factors.

As early human ancestors evolved into bipeds, changes occurred in the pelvis, hip joint and spine which increased the risk of osteoarthritis. Additionally genetic variations that increase the risk were likely not selected against because usually problems only occur after reproductive success.

The development of osteoarthritis is correlated with a history of previous joint injury and with obesity, especially with respect to knees. Since the correlation with obesity has been observed not only for knees but also for non-weight bearing joints and the loss of body fat is more closely related to symptom relief than the loss of body weight, it has been suggested that there may be a metabolic link to body fat as opposed to just mechanical loading.

Changes in sex hormone levels may play a role in the development of osteoarthritis as it is more prevalent among post-menopausal women than among men of the same age. A study of mice found natural female hormones to be protective while injections of the male hormone dihydrotestosterone reduced protection.