Hip pain is a common symptom that can be described in varying degrees of intensity. Finding relief is possible when the main cause is rooted out. Here are some of the causes behind it. Before we get into it let’s take a quick look at what your hip is made of. Your hip is where the thigh bone meets the pelvis to create a ball-and-socket joint. It is also one of the largest weight-bearing joints of the body that consists of two main parts – the femoral head and acetabulum. The ball and socket are both lined with articular cartilage which is a tissue that cushions the two bones to prevent them from rubbing against each other. The ball is anchored firmly into the socket with connective tissues called ligaments. Overlaying these ligaments are your leg muscles. A healthy hip supports your weight and allows you to move without pain. However, changes in the hip due to disease or injury affects your gait and places significant stress on joints above and below the hip. Since the large muscles of the thighs support and move the hip, it takes strong force to seriously damage it. For some people, hip pain is already a pressing problem. If you fall under this category of people, here are potential reasons as to why this is so. Arthritis, or joint inflammation, has more than a hundred variations. Among these, osteoarthritis and Inflammatory arthritis are the ones that commonly attack the hip joint. However, between the two, osteoarthritis is the usual culprit behind hip arthritis. This is the wear and tear of the cartilage resulting in painful symptoms during middle age. Since it’s a degenerative condition, the symptoms will likely worsen as the cartilage that cushions the joint breaks down. Inflammatory arthritis, on the other hand, is caused by an overactive immune system. Pain follows inflammation, and it may come from the joint itself or nearby structures. An immune system on hyper mode can trigger the release of chemical substances that attack and destroy the cartilage on both hip joints such as in autoimmune diseases like rheumatoid arthritis. It may also affect the spine (ankylosing spondilitis) where long-term inflammation causes spinal pain that radiates to other joints, including the hips. Certain inflammatory conditions like Systemic Lupus Erythematosus (SLE) causes bone cells to die, and this process comes with mild to excruciating hip pain. One hallmark that sets apart these two arthritic causes, is that pain from osteoarthritis worsens with activity. Meanwhile, pain from inflammatory causes is often eased with movement. 2. Hip FracturesA hip fracture is a break in the upper quarter of your thigh bone. It is often sustained from a fall or a direct blow to the side of the hip. There are also medical conditions, such as cancer, stress injuries, osteoporosis, that weakens the bone and makes it prone to breaking. A fractured hip may create significant pain in your hip and groin making it hard for you to walk. For some who can still be mobile, a faint sensation of pain can be felt along the hips, thighs, butt, back, or groin. X-rays, MRIs, and bone scans are diagnostic tools that can help determine if the pain is indeed caused by a broken hip. 3. Bursitis (Trochanteric Bursitis)Bursa is a fluid-filled sac that acts as a gliding surface that reduces friction between moving tissues of the body. The hips have two major bursae, and if it gets irritated or infected it can lead to Bursitis. Hip or trochanteric bursitis is also a common cause of hip pain characterised by tenderness along the outer portion. It worsens with physical activity, especially when walking up the stairs or when lying down on the affected side. 4. Hip TendonitisHip tendonitis is an inflammation or deterioration in the tendons (the thick cord that attaches the muscles to your hip bone) due to overuse. It is common in athletes who participate in sports like running, swimming or cycling. You can also sustain such injuries during high intensity workouts. A common symptom of hip tendonitis includes hip pain that happens gradually. It can cause tenderness over the area where the tendon starts. You may also notice your hip feeling stiff in the morning or after long periods of rest. It is also associated with discomfort when contracting the hip muscles. Pain lessens when you warm up, but it intensifies as the day progresses. 5. Hip StrainA hip strain occurs when the hip joint is overstretched way beyond its limits or is torn. It can be a simple stretch in your muscle or tendon, or it can be a partial or complete tear. Depending on the extent of damage, hip pain can range from mild, moderate, or severe. In worse case scenarios, you may have a limited ability to move your hip. Besides pain and tenderness on the affected area, a strained hip also becomes swollen. Pain also increases when you use the muscle thus limiting your range of motion. Eventually, this will lead to muscle weakness. Unfortunately, injured muscles become vulnerable to reinjury. Frequent muscle strains around the hip and pelvis may lead to athletic pubalgia or sports hernia – a strain or tear of the soft tissues in the lower abdomen or groin. 6. Hip Labral TearThe hip labrum is a crescent-shaped cartilage structure that lines the rim of the hip socket. A labral tear is an injury to this area caused by a build up of repeated minor traumas during high impact sports such as golf or football. It can also be sustained through a sudden major trauma to the hip joint. A labral tear is characterised by deep groin pain or pain in the buttocks along the side of the injured hip. You can expect hip pain and stiffness when you rotate in certain directions which leads to a decreased range of motion of the hips. Furthermore, any motion is accompanied by a clicking or locking sound deep within the hip joint. There are a number of cancers that are associated with hip pain. One is primary bone cancer where the tumor originates in the bone. Chondrosarcoma is a form of primary bone cancer that will most likely affect the hips because it grows in flat bones like your shoulder blade or pelvic bone and the hip bone. Metastatic cancers (malignancies that spread from one part of the body to another) cause hip pain when it invades the bones. Cancers that often lead to bone metastasis include breast, prostate, lung, and multiple myeloma. This may cause dull pain that is accompanied by swelling at the site of metastasis. Bone pain is commonly one of the presenting features of Leukemia – a type of blood cancer. Weeks after bone pain begins, swelling of the large joints such as the hips and shoulders follow suit. This is caused by the overcrowding of cancer cells in the bone marrow. 8. Avascular Necrosis (Osteonecrosis) Avascular necrosis of the hip is a painful condition that is caused by an interruption in the blood supply to the head of the thigh bone. When the area is deprived of good blood supply, bone cells start to die in stages. The initial symptom is hip pain characterised by a dull or throbbing ache in the groin or buttock area. As the disease progresses, the hip joint may become difficult to move causing you to limp while walking. It will even be impossible for you to cross your legs while you sit. These symptoms worsen at night. However, early treatment has shown positive outcomes. 9. Hip ImpingementA hip impingement, or a femoroacetabular impingement (FAI), is the abnormal contact that wears off the ball and socket of the hip joint. This can be caused by a misshapen femoral head, a deformed femoral neck, or a hip socket that covers too much of the femoral head. This increases the friction during hip movement which may eventually lead to joint damage as the cartilage wears away. Hip impingement is often associated with groin pain after prolonged sitting or walking. Athletes often experience this sensation with deep flexion or rotation of the hip during activity. A popping or clicking sound may also be felt, and pain may radiate along the side of the thigh and buttocks. 10. Septic Joint / Infected Hip JointThis is an inflammation of the hip joint caused by an infection (septic hip joint) which can either be fungal, viral or bacterial in nature. Symptoms include anterior hip or groin pain, swelling, warmth, and limited hip movement. These symptoms may also be accompanied by chills and fever. 11. Gynaecological or Pelvic Floor IssuesYour pelvis houses structures that are jammed so close together that any abnormal response may result in referred pain, which can be confusing. The pain which you think is from your hips may actually come elsewhere inside your pelvis. For instance, urological and gastrointestinal issues such as prostate cancer or gastroenteritis can trigger painful sensations that can be mistaken for a hip injury. Therefore, it is necessary that you seek the help of your primary care physician for a thorough evaluation. Don’t just let that hip pain to linger. Seek the right help and get it as soon as possible. Book a consultation with Dr. Andrew Quoc Dutton, a Harvard Fellowship-trained Orthopaedic Surgeon with specialisation in complex arthroscopic and reconstructive joint surgeries.