Hip, the largest joint in our body, is a stable ball-and-socket joint, which is formed between the thigh bone called femur and the three pelvic bones. Embedded in the synovial cavity containing synovial fluid, hip joint is protected by a slimy and smooth tissue called cartilage.
Hence, cartilage along with the synovial fluid assist the joints in enabling the bones to rub against each other, without creating friction and pain.
What Is Hip Arthritis?
Even though, many types of arthritis can affect hip joint, osteoarthritis or degenerative joint disease is the most common form of arthritis that affects hips. Hip osteoarthritis or degeneration of hip joints occurs primarily due to the gradual deterioration of cartilage, a shock-absorbing tissue that plays a crucial role in cushioning and protecting joints.
The slow and steady erosion of the cartilage and hip joint makes the surface between two bones rough, thus creating considerable amount of pain and friction, when there is a physical movement. Subsequently, this leads to stiffness, swelling and joint aches associated with hip arthritis.
Symptoms Of Hip Arthritis
Even though, hip arthritis progresses gradually without showing many symptoms in the beginning, the condition gets worse with time and the symptoms manifest themselves during cold weather, in the mornings, after rest or after excessive activity. Loss of flexibility or stiffness of the hip joint is the earliest symptom of hip arthritis.
In fact, the pieces of the damaged cartilage and joint can be seen floating in the synovial fluid. Besides a restriction in the range of motion of hips, severe pain in the buttock region, especially in the groin and the front and side of the hip after performing strenuous physical activities like exercise, walking or excessive use of the hip is yet another prominent symptom of hip arthritis.
The inflammation and pain can progressively weaken the muscles and the thigh bone, thus making the patient more prone to lower limb fractures.
Causes Of Hip Arthritis
Being an autoimmune disorder, rheumatoid arthritis occurs due to an overactive immune system that releases antibodies against its own body’s cells and tissues, thus leading to prolonged inflammation of the joints. The release of inflammatory substances leads to redness and swelling of the synovial membrane that lines the hip joint.
An inflamed membrane reduces its production of synovial fluid that lubricates the cartilage. This leads to considerable damage of the cartilage, joints and bones that support the hip, thus causing pain, swelling and other symptoms associated with hip arthritis.
Traumatic Injury Or Avascular Necrosis
Keeping in view the strength and the large size of the thigh muscles that support the hip, it takes a large amount of force to injure or damage the hip joint. However, major road accidents and severe falls that place excess of weight on the hip joint contribute to 90% of all hip fractures.
A serious hip fracture can also lead to a condition called osteonecrosis or avascular necrosis, which is characterized by the loss of blood supply to the femoral head of the thighbone that forms the ball of the hip joint. As a result, the bone starts to deteriorate and the cartilage and the surrounding tissues also begin to wither.
A history of such hip injuries and a surgery to the hip joint can increase the risk of developing hip osteoarthritis. Moreover, repetitive trauma to the hip and the surrounding cartilage, ligament, tendon and bones in military personnel, weightlifters and sport players can act as a major contributing factor for hip osteoarthritis.
A national survey conducted in Australia has established a strong correlation between the increase in the rate of obesity with the rise in the prevalence of hip arthritis. In fact, the risk of developing hip osteoarthritis was found to be seven times higher in obese people than in people who had a normal weight.
Moreover, the severity of the disease worsened with an increase in weight, with obese people experiencing more pain, joint stiffness and dysfunctional hip joints. Hence, excess of mechanical stress placed by an overweight body on the hips exacerbates the daily wear and tear of the cartilage and leads to the complete loss of cartilage, eventually leaving the rough surface of the bones underneath exposed.
An age over 50 significantly increases your chances of developing hip arthritis, which doubles every 5-6 years thereafter. Natural process of aging decreases the composition of protein and increases the water content of the cartilage. This leads to the gradual degeneration of cartilage that forms tiny flakes and floats in the synovial cavity.
The synovial fluid lacks any nutrients that can aid in healing the worn out cartilage. Hence, over a period of time, with increase in activity and age, the cartilage, which acts as a cushion or supporting pad for the hip joint is completely lost.
This limits the motion of joints and elicits pain during physical movement in older people, making them far more prone to hip arthritis than the younger generation.
Most often affecting the elderly population, osteoporosis can make the bones brittle and weak. Osteocytes or bone cells actively participate in bone turnover by getting continuously absorbed and replaced by the body.
However, a disturbance in the replacement of the bone cells leads to the loss of bone tissue, making it far more susceptible to bone fractures and injuries. This in turn, destroys the joints and the cartilage surrounding the bones, thus leading to hip arthritis.
Although, cartilage provides flexibility to our joints, it exhibits a certain degree of rigidity and stiffness for allowing joints, especially hip joints to bear excess weight. However, cartilage is filled with water and is devoid of any blood vessels.
Hence, once worn out due to excessive use or involvement in activities that involve placing an extra weight on the hips, it gets extremely difficult for the cartilage to repair on its own, unlike damaged bones, which utilize the blood vessels that they are enriched with.
Hence, over a period of time, repetitive forces or stressing too much on the hip joint, beyond what it can endure, especially during activities like dancing, soccer, basketball, weight lifting can make you very susceptible to hip osteoarthritis.
In addition, genetic predisposition to hip osteoarthritis, congenital abnormalities or defective joints at birth, female gender, hormonal disorders like diabetes and gout serve as other important risk factors that contribute to the onset of hip arthritis.
Considering the importance of cartilage in enabling the hip joint to bear all the stresses during walking, sitting, bending, running and carrying out any other physical activity, degeneration of this tissue can hinder smooth movement of the hip. Hence, performing moderate aerobic exercise and strength training exercise on a regular basis can maintain optimum functionality of the hip and help you prevent the onset of hip arthritis.
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