Several risk factors of CMC OA of the thumb are known. Each of these risk factors does not cause CMC OA by itself, but acts as a predisposing factor influencing the process of OA in some way. Risk factors include: female gender, suffering from obesity, repetitive heavy manual labor, familial predisposition and hormonal changes, such as menopause.

CMC OA is the most common form of OA affecting the hand. Dahaghin et al. showed that about 15% of women and 7% of men between 50 and 60 years of age suffer from CMC OA of the thumb. However, in about 65% of people older than 55 years, radiologic evidence of OA was present without any symptoms. Armstrong et al. reported a prevalence of 33% in postmenopausal women, of which one third was symptomatic, compared to 11% in men older than 55 years. This shows CMC OA of the thumb is significantly more prevalent in women, especially in postmenopausal women, compared to men.

About 25% of people over the age of 50 experience knee pain from degenerative knee 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.

In the United States, more than US $3 billion is spent each year on arthroscopic knee surgeries that are known to be ineffective in people with degenerative knee pain.

Women in sports such as association football, basketball, and tennis are significantly more prone to ACL injuries than men. The discrepancy has been attributed to gender differences in anatomy, general muscular strength, reaction time of muscle contraction and coordination, and training techniques.

Gender differences in ACL injury rates become evident when specific sports are compared. A review of NCAA data has found relative rates of injury per 1000 athlete exposures as follows:

- Men's basketball 0.07, women's basketball 0.23

- Men's lacrosse 0.12, women's lacrosse 0.17

- Men's football 0.09, women's football 0.28

The highest rate of ACL injury in women occurred in gymnastics, with a rate of injury per 1000 athlete exposures of 0.33

Of the four sports with the highest ACL injury rates, three were women's – gymnastics, basketball and soccer.

According to recent studies, female athletes are two to eight times more likely to strain their anterior cruciate ligament (ACL) in sports that involve cutting and jumping as compared to men who play the same particular sports (soccer, basketball, and volleyball). Differences between males and females identified as potential causes are the active muscular protection of the knee joint, the greater Q angle putting more medial torque on the knee joint, relative ligament laxity caused by differences in hormonal activity from estrogen and relaxin, intercondylar notch dimensions, and muscular strength.

Rate in the United States have been estimated to occur among an at-risk population of 1,774,210,081 people each year. Incidence rates published in the American Journal of Sports Medicine for ages 10–17 were found to be about 29 per 100,000 persons per year, while the adult population average for this type of injury ranged between 5.8 and 7.0 per 100,000 persons per year. The highest rates of patellar dislocation were found in the youngest age groups, while the rates declined with increasing ages. Females are more susceptible to patellar dislocation. Race is a significant factor for this injury, where Hispanics, African-Americans and Caucasians had slightly higher rates of patellar dislocation due to the types of athletic activity involved in: basketball (18.2%), soccer (6.9%), and football (6.9%), according to Brian Waterman.

Lateral Patellar dislocation is common among the child population. Some studies suggest that the annual patellar dislocation rate in children is 43/100,000. The treatment of the skeletally immature is controversial due to the fact that they are so young and are still growing. Surgery is recommended by some experts in order to repair the medial structures early, while others recommend treating it non operatively with physical therapy. If re-dislocation occurs then reconstruction of the medial patellofemoral ligament (MPFL) is the recommended surgical option.

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.

SLAC and SNAC are both caused by injury, for example a fall on an extended hand. SLAC is caused by rupture of the scapholunate ligament, SNAC is caused by a scaphoid fracture which does not heal and because of that will develop in a non-union fracture. SLAC is more common than SNAC; 55% of the patients with wrist osteoarthritis has a SLAC wrist. Although they have a different underlying pathology, they both lead to abnormal wrist kinematics which will eventually lead to osteoarthritis of the wrist.

Isolated and combined posterolateral knee injuries are difficult to accurately diagnose in patients presenting with acute knee injuries. The incidence of isolated posterolateral corner injuries has been reported to be between 13% and 28%. Most PLC injuries accompany an ACL or PCL tear, and can contribute to ACL or PCL reconstruction graft failure if not recognized and treated. A study by LaPrade "et al." in 2007 showed the incidence of posterolateral knee injuries in patients presenting with acute knee injuries and hemarthrosis (blood in the knee joint) was 9.1%.

Training of the feet, utilizing foot gymnastics and going barefoot on varying terrain, can facilitate the formation of arches during childhood, with a developed arch occurring for most by the age of four to six years. Ligament laxity is also among the factors known to be associated with flat feet. One medical study in India with a large sample size of children who had grown up wearing shoes and others going barefoot found that the longitudinal arches of the bare-footers were generally strongest and highest as a group, and that flat feet were less common in children who had grown up wearing sandals or slippers than among those who had worn closed-toe shoes. Focusing on the influence of footwear on the prevalence of pes planus, the cross-sectional study performed on children noted that wearing shoes throughout early childhood can be detrimental to the development of a normal or a high medial longitudinal arch. The vulnerability for flat foot among shoe-wearing children increases if the child has an associated ligament laxity condition. The results of the study suggest that children be encouraged to play barefooted on various surfaces of terrain and that slippers and sandals are less harmful compared to closed-toe shoes. It appeared that closed-toe shoes greatly inhibited the development of the arch of the foot more so than slippers or sandals. This conclusion may be a result of the notion that intrinsic muscle activity of the arch is required to prevent slippers and sandals from falling off the child’s foot.

High school athletes are at increased risk for ACL tears when compared to non-athletes. This risk increases with certain types of sports. Among high school girls, the sport with the highest risk of ACL tear is soccer, followed by basketball and lacrosse. The highest risk sport for boys was basketball, followed by lacrosse and soccer. Children and young athletes may benefit from early surgical reconstruction after ACL injury. Young athletes who have early surgical reconstruction of their torn ACL are more likely to return to their previous level of athletic ability when compared to those who underwent delayed surgery or nonoperative treatment. They are also less likely to experience instability in their knee if they undergo early surgery.

Hypermobility syndrome is generally considered to comprise hypermobility together with other symptoms, such as myalgia and arthralgia. It is relatively common among children and affects more females than males.

Current thinking suggests four causative factors:

- The shape of the ends of the bones—Some joints normally have a large range of movement, such as the shoulder and hip. Both are ball and socket joints. If a shallow rather than a deep socket is inherited, a relatively large range of movement will be possible. If the socket is particularly shallow, then the joint may dislocate easily.

- Protein deficiency or hormone problems—Ligaments are made up of several types of protein fibre. These proteins include elastin, which gives elasticity and which may be altered in some people. Female sex hormones alter collagen proteins. Women are generally more supple just before a period and even more so in the latter stages of pregnancy, because of a hormone called relaxin that allows the pelvis to expand so the head of the baby can pass. Joint mobility differs by race, which may reflect differences in collagen protein structure. People from the Indian sub-continent, for example, often have more supple hands than Caucasians.

- Muscle tone—The tone of muscles is controlled by the nervous system, and influences range of movement. Special techniques can change muscle tone and increase flexibility. Yoga, for example, can help to relax muscles and make the joints more supple. Please note that Yoga is not recommended by most medical professionals for people with Joint Hypermobility Syndrome due to likelihood of damage to the joints. Gymnasts and athletes can sometimes acquire hypermobility in some joints through activity.

- Proprioception—Compromised ability to detect exact joint/body position with closed eyes, may lead to overstretching and hypermobile joints.

Hypermobility can also be caused by connective tissue disorders, such as Ehlers-Danlos Syndrome (EDS) and Marfan syndrome. Joint hypermobility is a common symptom for both. EDS has numerous sub-types; most include hypermobility in some degree. When hypermobility is the main symptom, then EDS/hypermobility type is likely. People with EDS-HT suffer frequent joint dislocations and subluxations (partial/incomplete dislocations), with or without trauma, sometimes spontaneously. Commonly, hypermobility is dismissed by medical professionals as nonsignificant.

The following factors may be involved in causing this deformity:

- Inherent laxity of the knee ligaments

- Weakness of biceps femoris muscle

- Instability of the knee joint due to ligaments and joint capsule injuries

- Inappropriate alignment of the tibia and femur

- Malunion of the bones around the knee

- Weakness in the hip extensor muscles

- Gastrocnemius muscle weakness (in standing position)

- Upper motor neuron lesion (for example, hemiplegia as the result of a cerebrovascular accident)

- Lower motor neuron lesion (for example, in post-polio syndrome)

- Deficit in joint proprioception

- Lower limb length discrepancy

- Congenital genu recurvatum

- Cerebral palsy

- Multiple sclerosis

- Muscular dystrophy

- Limited dorsiflexion (plantar flexion contracture)

- Popliteus muscle weakness

- Connective tissue disorders. In these disorders, there are excessive joint mobility (joint hypermobility) problems. These disorders include:

- Marfan syndrome

- Ehlers-Danlos syndrome

- Benign hypermobile joint syndrome

- Osteogenesis imperfecta disease

In 2010 national statistics was done by Agency for Healthcare Research and Quality for posterior cruciate ligaments injuries. They found that 463 patients were discharge for having some type of PCL injury. The 18- to 44-year-old age group was found to have the highest injuries reported (figure 1). One reason why this age group consists of the majority of injuries to the PCL is because people are still very active in sports at this age. Men were also reported having more injuries to the PCL (figure 3).

Ankle sprains can occur through either sports or activities of daily living, and individuals can be at higher or lower risk depending on a variety of circumstances including their homeland, race, age, sex, or profession In addition, there are different types of ankle sprains such as eversion ankle sprains and inversion ankle sprains. Overall, the most common type of ankle sprain to occur is an inversion ankle sprain, where excessive plantar flexion and supination cause the anterior talofibular ligament to be affected. A study showed that for a population of Scandinavians, inversion ankle sprains accounted for 85% of all ankle sprains Most ankle sprains occur in more active people, such as athletes and regular exercisers.

Tibial plateau fractures constitute 1% of all fractures. Peak age is 30–40 years old in men and 60-70 in women. Approximately half of the people who sustain a tibial plateau fracture are aged over 50 years old.

Flat feet can also develop as an adult ("adult acquired flatfoot") due to injury, illness, unusual or prolonged stress to the foot, faulty biomechanics, or as part of the normal aging process. This is most common in women over 40 years of age. Known risk factors include obesity, hypertension and diabetes. Flat feet can also occur in pregnant women as a result of temporary changes, due to increased elastin (elasticity) during pregnancy. However, if developed by adulthood, flat feet generally remain flat permanently.

If a youth or adult appears flatfooted while standing in a full weight bearing position, but an arch appears when the person plantarflexes, or pulls the toes back with the rest of the foot flat on the floor, this condition is called flexible flatfoot. This is not a true collapsed arch, as the medial longitudinal arch is still present and the windlass mechanism still operates; this presentation is actually due to excessive pronation of the foot (rolling inwards), although the term 'flat foot' is still applicable as it is a somewhat generic term. Muscular training of the feet is helpful and will often result in increased arch height regardless of age.

Those with hypermobile joints are more likely to have fibromyalgia, mitral valve prolapse, and anxiety disorders such as panic disorder.

Wrist osteoarthritis is a group of mechanical abnormalities resulting in joint destruction, which can occur in the wrist. These abnormalities include degeneration of cartilage and hypertrophic bone changes, which can lead to pain, swelling and loss of function. Osteoarthritis of the wrist is one of the most common conditions seen by hand surgeons.

Osteoarthritis of the wrist can be idiopathic, but it is mostly seen as a post-traumatic condition. There are different types of post-traumatic osteoarthritis. Scapholunate advanced collapse (SLAC) is the most common form, followed by Scaphoid Non-union Advanced collapse (SNAC). Other post-traumatic causes such as intra-articular fractures of the distal radius or ulna can also lead to wrist osteoarthritis, but are less common.

Jefferson fracture is often caused by an impact or load on the back of the head, and are frequently associated with diving into shallow water, impact against the roof of a vehicle and falls, and in children may occur due to falls from playground equipment. Less frequently, strong rotation of the head may also result in Jefferson fractures.

Jefferson fractures are extremely rare in children, but recovery is usually complete without surgery.

In a study comparing the prevalence of ankle sprains between age, race, and sex, individuals who were aged 10–19 years old had highest incidences of ankle sprains. It can be suggested that adolescents are more physically active, which leads to higher chances of ankle sprains. Since sports deal with high utilization of the ankle, over 50% of ankle sprains are due to sport related injuries.

Genu recurvatum is a deformity in the knee joint, so that the knee bends backwards. In this deformity, excessive extension occurs in the tibiofemoral joint. Genu recurvatum is also called knee hyperextension and back knee. This deformity is more common in women and people with familial ligamentous laxity. Hyperextension of the knee may be mild, moderate or severe.

The normal range of motion (ROM) of the knee joint is from 0 to 135 degrees in an adult. Full knee extension should be no more than 10 degrees. In genu recurvatum (back knee), normal extension is increased. The development of genu recurvatum may lead to knee pain and knee osteoarthritis.

Future research into posterolateral injuries will focus on both the treatment and diagnosis of these types of injuries to improve PLC injury outcomes. Studies are needed to correlate injury patterns and mechanisms with clinical measures of knee instability and laxity.

Most commonly due to anterior shoulder dislocation caused by hyperabduction and external rotation of the arm. Usually in young men who play contact sports (E.g. rugby, football, volleyball, basketball, etc.). Frequent anterior (frontward) subluxation also poses a great risk factor.