What Is Hip Pain?

The structure known as the hip joint is a crucial part of human anatomy. This structure allows for normal everyday movements. These include standing upright, sitting, and walking. The hip joint also plays an important role in supporting and balancing the torso, and in completing additional motions such as bending, jumping, twisting, or compound movements that involve one or more of these.

The hip is a ball and socket type joint, which is one of the most common joints in the human body. The “socket” in question is the acetabulum, a shallow bowl-like feature of the pelvis. This lines up with the top of the femur, a round (“ball”-like) mass of bone. These structures are coated with protective material called the articular or hyaline cartilage.

Cartilage is a resilient, flexible material that is similar to connective tissue. It is rich in a protein called collagen. In addition, bag-like structures containing a material called synovial fluid surround the joint. These prevent friction resulting from direct contact between the bone surfaces as above, and protect against shocks and blunt force acting on the joint. This contributes to the prevention of chronic pain and reductions in the normal function and movement of the joint.

The pelvis is connected to the thighbone by ligaments. Under normal, disease-free circumstances, the hip joint has a varied range of flexibility and motion. This range is defined by general pelvic structure. Hip motion is also limited by the labrum that surrounds the joint. Hip pain may be associated with damage to or disorders in many tissues in and around the joint.

Must Watch Video – What is Hip Pain?

Hip pain is a type of pain relevant to many people in the United States today. It may be commonly perceived as an issue that affects older people, but can in reality affect individuals of many age groups. The hip is a joint (or articulating junction) where the pelvic bone and the thighbone (the femur) meet. Many forms of hip pain are localized to the joint itself. However, some conditions associated with hip pain may also result in pain that radiates further down the leg. Hip pain may have an onset or intensify in response to normal activities such as walking. It may progress to a point at which such activities are significantly impaired or otherwise affected.

Hip pain may be associated with one or more of the tissues that comprise this joint. These include:

  • Bones
  • Cartilage
  • Muscles
  • Ligaments
  • Tendons

One of the strategies to address this situation includes surgery to remove either the degenerative parts of a joint, or an entire section of the affected joint. Abnormal or missing parts of bones may be replaced with synthetic medical materials, such as surgical cement. However, these surgeries in themselves may prove to be a source of chronic pain.

Causes Of Hip Pain

Hip Pain In Seniors

Many cases of hip pain are associated with damage to joints that is progressive, or increases over time. Some research indicates that one person in every four will experience this by the time they reach the age of 85.

hip painThis may be referred to as joint degeneration, and is affected by a number of variables or risk factors.

These include:

  • Structural abnormalities in bones, which become advanced over time
  • The loss of the tissues, or molecular structures, that makes up bones (this may also be progressive)
  • Reductions in or impairments of normal joint movement
  • Increased weaknesses in the muscles and other tissues that support and surround the joint

These variables may contribute to persistent pain, or increased disability or reduced activity over time.

Fractures may be related to osteoporosis (progressive bone density loss), which is associated with advancing age, particularly in women. The risk of fracture is also associated with the increased risk of falls or hip injuries, which may also be linked to increasing age. Fractures are associated with decreases in the life quality and functional status of those affected. Bone loss may also affect the femoral head, where it interfaces with the socket of the pelvis. This may also be associated with osteoporosis. This wearing-away (or degeneration) of the femoral head may also be associated with chronic pain and increased disability.

Osteoarthritis is another condition associated with advancing age that may be a source of hip pain. This disorder affects approximately one in ten people in the developed world. It is an autoimmune disease, in which components of the immune system target tissues within joints as if they were foreign or infective particles, leading to inflammation in the joint. Inflammation is associated with pain, and may be chronic in nature. This condition is not related to bone loss. However, it is a prominent cause of hip replacements.

Pediatric Hip Pain

As mentioned earlier, hip pain does not only affect seniors. People of other age ranges may also experience this type of pain. Hip pain in younger individuals may be associated with some known risk factors, including:

  • Occupational hazards
  • Accidents and other trauma
  • Additional forces or wear and tear on the joint
  • Anomalies in the structure of the joint
  • Certain conditions and disorders

Persistent or acute hip pain may be associated with disorders or diseases experienced as a child. Some hip damage may occur in children in the course of normal activity. This may require corrective surgery or therapy. Pediatric hip pain may also be associated with acute or persistent conditions. These may be the result of genetic mutations or hereditary conditions. For example, cerebral palsy and Down’s syndrome are associated with hip joint instability and with hip pain that may be experienced for life. Another factor that may be associated with pediatric hip pain is increased body mass.

Infants may also be subject to structural hip anomalies. This is not necessarily a source of pain if addressed with adequate and timely corrective procedures.

In this population, the head of the thighbone is still elongating at a point called the growth plate. This may be subject to damage, which is a disorder known as slipped capital femoral epiphysis (SCFE). This is often linked to chronic pain in young people. SCFE is also associated with serious complications such as avascular necrosis (or tissue death related to disruptions in blood flow) of the femur and juvenile arthritis. Therefore patients with SCFE may require total hip replacement to treat or prevent these conditions. SCFE is associated with some risk factors, including extensive physical activity and trauma.

Hip Pain In Teenagers And Younger Adults

Teenagers and young adults may sustain hip pain in the course of strenuous athletic activity. This may occur due to strain, excessive use, increased force, or accidents involving the hip joint while engaged in activities such as competitive sports or running. This age group may also be at risk of hip dislocation or fractures. Those who experience any of the above may need to undergo surgery or rehabilitative therapy to regain normal hip function and recover from pain.

Hip pain in adults and teenagers may also be related to femoroacetabular impingement (or FAI). This condition results in excessive friction between the bony surfaces of the joint, resulting in pain and increased disability. This condition is often seen in younger people who engage in extensive sporting or athletic activities. FAI is often a consequence of the greatly increased movement of the hip while doing so. This may be sustained in the course of high-volume running and other similar activities while training or playing sports.

There are some major sub-types of FAI. “Cam: impingements occur when excessive bone growth takes place around the edge of the femoral head. This results in increased difficulty and pain when trying to move it within the acetabulum.  “Pincer”-type impingements occur due to increased bone growth within, or structural anomalies in, the “socket” of the joint. Again, this may result in increased difficulty in moving the joint. These impingements may also result in labral tears. The labrum is a band of cartilage located around the two main bones of the joint. A labral tear can result in chronic pain that persists long-term. Factors that affect the duration of the pain include misdiagnosis. Labral tears may be mistaken for other sources of hip pain, including muscular damage or conditions that affect the bones of the joint. Impingements and labral tears may be corrected with surgery. The labrum can be reconstituted or replaced with a graft from the patient’s other tissues.

The hip joint, along with the pelvis and lower back, may be adversely affected by the regular use of shoes that impose additional stress and forces on these bones. A prominent example of this is footwear with high heels.

Additional Risk Factors In Hip Pain

Hip Joint - Anatomy BonesThere are many other risk factors associated with hip pain. The sacroiliac joint connects part of the spine with the pelvis, and contains nerves that are responsible for parts of the body below this point. Therefore, damage to the sacroiliac joint may be felt as pain in the vicinity of the hip joint. Inadvertent injury to nervous tissue sustained in the course of surgery on the lower back may have a similar effect.

Some central nervous system anomalies also result in hip pain. An example of this is heterotopic ossification, or the growth of additional bone tissue in the head of the femur. This may result in pain in a similar fashion to that associated with FAI. Heterotropic ossification can be associated with inflammation.

Another common cause of hip pain is pain experienced after surgery and during recovery. This may also become chronic, or pain that persists beyond the time frame normally associated with recovery. These surgeries are often joint replacements, also known as hip arthroplasty. These procedures involve the total or partial replacement of the joint surfaces with prostheses. These are constructed of medical-grade acrylic or high-quality metal, such as titanium. These materials, or the type of prosthesis used, may influence the severity and duration of pain after surgery. Hip pain following arthroplasty can also be related to the migration of the prosthesis, or of its failure to integrate with the rest of the bone. Hip pain may also be associated with septic failure of the new prosthesis, in which the implant becomes infected. This can also result in failure or migration.

Hip pain is conveyed to the brain by nervous tissue in the lower (lumbar or sacral) regions of the spine, as mentioned above. Chemical (e.g. inflammation) or mechanical damage to this nervous tissue may result in chronic hip pain.

Hip Pain Diagnosis

The detection of the precise causative factor in a case of hip pain may be a difficult and complicated procedure. A pain specialist or physician will initiate a diagnosis by interviewing the patient. This may include questions about the region of the hip (or hips) in which pain is experienced, the duration of the pain, its severity, and whether the pain is constant or fluctuating.

Visualizing the joint using imaging technology such as ultrasound or magnetic resonance imaging (MRI) can help with a diagnosis. These techniques may enhance the detection of adverse events such as fractures or FAI. Computerized tomography (CT) is another imaging method also used in the diagnosis of hip pain. However, some research indicates that MRI is more effective than CT in this. The physician or specialist may also ask questions concerning the possibility of the presence of one or more risk factors, such as those outlined above.

The doctor may also physically examine the patient, which may contribute to diagnosis particularly when an injury sustained during training or sporting activities is suspected. A skilled physician can detect conditions, such as labral tears, that go undiagnosed by imaging techniques. X-ray techniques are also still employed in diagnosis, but are often substituted for other methods in response to concerns about radiation exposure.

Arthritis of the hip jointHowever, it is applicable in patients with hip replacements composed of metal. The assessment of subjective pain ratings by patients may also contribute to a diagnosis in cases of hip pain. These tools applied to hip pain include the Hip Outcome Score-Activities of Daily Living (HOS-ADL), Non-Arthritic Hip Score (NAHS), and the Harris Hip Score. Some interventional procedures may also help to diagnose hip pain. These techniques may pharmacologically inhibit pain emanating from a specific type of tissue, including nervous tissue, or from specific structures, such as joints. A positive response to one of these may narrow the source of pain down to the region or tissue targeted. Some of these interventions may also be applied to the treatment of hip pain, and are described below.

Treatments For Hip Pain

Drug Therapy

Conventional pharmacological agents to reduce pain, or analgesics, are commonly indicated after a diagnosis of hip pain. Drugs recommended to treat hip pain may include many widely-available prescription and non-prescription drugs. One may be chosen based on the severity of the pain. Non-steroidal anti-inflammatory drugs (NSAIDs, e.g. indomethacin or aspirin) are often indicated for some forms of hip pain. These drugs are associated with the effective inhibition of inflammation in joints and other tissues. They are commonly indicated in cases of hip pain associated with sports-related activity or injuries. NSAIDs are associated with side effects, including the increased risk of gastric ulcers, acid reflux, and kidney damage.

If these medications fail to generate the expected treatment effect, a physician and patient may consider opioid painkillers. These are a class of powerful painkillers that include well-known drugs such as morphine and oxycodone. These molecules bind to the major pain receptors in the body and prevent them from propagating their signals to the brain. Fentanyl is a relatively new form of opioid that may be administered to patients following a hip replacement surgery. Fentanyl can be delivered via pump-like implants placed under the skin, which are activated by the patient at need.

The disadvantages of opioid therapy include their relatively high addictive and dependence-forming profiles. Other adverse effects associated with opioids include respiratory distress and organ damage. Patients in chronic pain who find that other forms of therapy (which may include all of the alternatives listed here) are not effective in their case may consider opioids. A physician or pain specialist will comprehensively assess their suitability and risks of adverse events before prescribing these analgesics.

Nerve Blocks

Hip InjectionThese are interventions that may also be used in the diagnosis and treatment of hip pain. A nerve block is an administration of local anesthetics (e.g. bupivacaine or lidocaine) directly into the outer regions of the spinal cord through a needle. Steroids, which effectively reduce inflammation, may also be included in the injected formulation. Before a nerve block is administered, the specialist or physician will numb the skin through which the needle will be introduced to reduce discomfort during the procedure. This needle is guided by imaging techniques to ensure accurate, safe injection and delivery of the drugs. A nerve block is performed to inhibit the pain signals of spinal nerves that serve the hip region.

These injections target the hip joint directly, and may effectively reduce pain and inflammation emanating from within the joint. Nerve or joint injections are relatively non-invasive, and may be used as an alternative to more extensive procedures such as surgery. Pain-blocking injections can also prevent or postpone the need for invasive procedures.

Nerve blocks are associated with some risks and side effects. These can be related to inaccurate needle placement or injection. This may result in damage to structures or regions that were not the target of the injection. This can result in reduced motor control, numbness, and discomfort. More common side effects include an acute headache or temporary numbness.

The side effects associated with steroids, if applicable, include increased irritability, changes in bodyweight, and immune system suppression. Steroids are also linked to increased risks of osteoporosis and arthritis. Hip joint injections may also be associated with side effects such as changes in the pigmentation of the skin above the injected joint and swelling in the injected area after the procedure. Tendon rupture after joint injection has been reported in isolated cases.

Radiofrequency Ablation

Radiofrequency ablation is an alternative procedure in which nerves are also prevented from sending painful signals. This is achieved using thermoelectric (or radiofrequency) energy to disrupt the ability of the nerve to do this. Following the administration of a local anesthetic to the skin over the nerve to be targeted, a long, thin probe is extended toward this tissue. The probe will emit just enough energy to disrupt the parts of the nerve responsible for pain signals. This should leave other nervous functions such as sensation intact. These specific regions of nerve tissue can be identified and targeted using imaging technology.

The risks associated with radiofrequency ablation include bleeding and discomfort in the area of the skin punctured to reach a nerve. This skin may also become infected unless covered and cleaned adequately. Other adverse events may be related to inaccurate probe placement. These include numbness, motor impairments, and discomfort. Radiofrequency ablation is safe and effective in the majority of cases, however, and may provide pain relief that lasts a number of months.

Spinal Cord Stimulation

If the options mentioned above prove ineffective, a patient may consider other forms of pain relief that are more permanent. One of these options is spinal cord stimulation (SCS). This involves the placement of a device within the area of the spine, in a region similar to the target of spinal nerve blocks. The implant includes long, thin electrodes. These emit a small electrical signal that is similar to the normal signals sent by nerves responsible for a region such as the hip joint. These signals override (or modulate) the pain signals of these same nerves. The device is often connected to leads that run outside the body to a control device. The patient can activate this device to generate the pain-correcting signals at need. SCS may effectively treat many types of chronic pain.

This procedure is associated with some risks. This includes the accumulation of scar tissue around the device, which may result in chronic pain. The electrodes may also migrate away from their optimal location. This can result in the absence of pain relief, and of new-onset pain or neurological complications. These adverse events are present in a minority of cases, however.

Physical Therapy And Rehabilitation

Recovery from a hip replacement may be associated with reductions in normal activity and function. This in turn may be associated with the increased probability of further disability, as the patient is discouraged from moving due to pain and reduced conditioning in ligaments and muscles. This may be addressed through physical therapy. This involves specific exercises, stretches, training, and conditioning. Constrained movement therapy and kinesitherapy are newer forms of this treatment. Physical therapy may also be a component of rehabilitation for athletes or sportspeople recovering from corrective surgeries. This can contribute to a return to full performance following recovery.

TENS Units

Spinal nerves may also be modulated through stimulation delivered outside the body. Treatments based on this include transcutaneous electrical nervous stimulation (TENS). TENS involves the placement of pads containing electrodes on the skin above nerves. These electrodes emit electrical impulses to produce an effect similar to that of SCS. This treatment can be offered to older patients who suffer from pain associated with osteoarthritis or osteoporosis. A clinical trial assigned either TENS or a placebo treatment to 68 patients recovering from surgery. Fentanyl intake in the group receiving TENS was significantly decreased compared to the placebo group. This indicates the potential of this treatment in cases of pain resulting from hip surgery. The main advantages of TENS are that it is non-invasive and associated with mild side effects. These include redness, burning, or stinging in the skin under the pads, and temporary muscular pain.

Prevention of Hip Pain

Hip BursitisThe probability of hip pain can be controlled through prevention. This involves the reduction of exposure to the environmental or occupational risk factors that cause hip pain. For example, people involved in high-volume training may avoid hip pain by avoiding the over-exertion of the joint or its damage through poor techniques. These include aberrant running or gait styles. The analysis of these may reveal areas of technique or habit that pose an increased danger to the hip joint. This can also indicate where improvements in gait, that conserve the hip region, can be made.

Hip damage may also be associated with cartilage, ligament, or muscle strain or tearing. This can be avoided through adequate warming-up, stretches, and cooling-down. Pain may also be prevented by reducing the amount of potentially harmful behaviors done during training. These include running down inclines, which is associated with an increased risk of hip joint damage. The probability of hip pain may also be managed by adhering to training programs that include measures to avoid injury or wear-and-tear on the joint.

While exercise when not carried out properly may contribute to hip pain, exercise can also play a role in the prevention of hip pain. The maintenance of a moderate regimen of flexibility and resistance training is recommended for those who wish to reduce the risks of hip pain. This may be linked to observations of the beneficial effects of regular activity on the retention of muscle mass and bone density in seniors. Age-related muscle deterioration is associated with osteoarthritis and an increased risk of fractures related to osteoporosis. The retention of the tissues, including muscles, around the hip may promote the stability of the joint, and thus possibly reduce the risk of pain. In addition, the regeneration of bone is associated with stimulation caused by the movement of the tissues around it.

Other Methods Of Hip Pain Management

hip bursitisSome alternative treatments and interventions that address hip pain are currently proposed in scientific literature or are in development. Many of these are variations and new approaches to hip replacement. One of these is a minimal incision replacement procedure (also known as arthroplasty). These are distinct from standard arthroplasties in terms of the position and numbers of incisions made to place an implant.

Minimal incision arthroplasty is associated with reduced blood loss and recovery times compared to standard procedures. However, pain severity or duration as a result of minimal-incision surgeries is similar to that following standard arthroplasty. Another alternative to standard arthroplasty is reconstruction of the femoral head, in which missing bone tissue is replaced with acrylic cement. This approach has not resulted in appreciable differences in pain intensity.

Many cases of hip pain are related to synovial fluid loss, and thus increased contact between the bones of the joint. This is associated with conditions such as FAI and arthritis. Synovial fluid replacement (or viscosupplementation) may be performed using sterile biomaterials such as hyaluronic acid. This may have potential in pain reduction, and is currently under evaluation as a treatment option in cases of osteoarthritis. Viscosupplementation of the hip joint requires more testing or development before approval as a treatment option.

Another alternative treatment similar to arthoplasty is arthroscopy, in which damage to a joint is surgically visualized and sometimes also corrected. This is associated with significant improvements in functional status and pain scores for patients who underwent hip arthroscopy, according to some research. This technique has experienced a considerable amount of development since its introduction.

Arthroscopy is completed using an endoscope, to reduce invasion and damage to tissues. A surgeon may prefer to operate while the patient lies on his or her back or on their side with the hip to be evaluated uppermost. Arthroscopy can be completed using nerve blocks, (as described above) a similar injection into the femoral nerve, or a general anesthetic. The surgeon may have to dissociate the joint slightly using traction. This allows access to and visualization of the interior of the hip. This is enhanced using imaging techniques such as fluoroscopy.

Arthroscopy is often applied to disorders such as labral tears or FAI. In cases where impingements are detected, the excess bone formed on the femoral head or acetabulum is shaved off using small drill-like equipment. The labrum may be replaced using grafts, as above, or alternatively repaired. Arthroscopy may also be used in the correction of hip abnormalities in infants, thus avoiding a more chronic pain condition for these patients in the future.

These procedures are gaining support as a treatment linked to favorable outcome profiles. Arthroscopy may result in positive effects on the duration and intensity of pain in recovery. Research has demonstrated that patients treated for injuries and damage incurred while training, using arthroscopy, experience a significant decrease in the time taken to regain their form, compared to conventional procedures.

Arthroscopy is associated with some adverse events and side effects, however. These are mainly related to general anesthetics, if used. The after-effects of this may include respiratory depression, nausea, and difficulty in passing urine. If nerve blocks are used as alternative anesthesia, this may result in the adverse effects described earlier. Other complications include the development of infection in the hip or the incisions made. Some estimates suggest that this occurs in about 1% of all cases. Some cases of nerve damage, sustained in the course of traction or as a result of surgeon error, have also been reported. This can be associated with new-onset pain, which may become chronic. The rate of all complications in cases of hip arthroscopy is approximately 6%. However, arthroscopy has been shown to be effective in many cases, and may have potential in the treatment of hip pain associated with other sources, such as implant failure following arthroplasty.

Another potential target in pain management research is nerve growth factor (NGF). This protein controls the differentiation of stem cells into nerve cells. It also contributes to the regulation of pain signals as they are conducted from cell to cell. Clinical trials of new compounds that antagonize these actions have demonstrated potential in cases of hip pain. These studies have compared these NGF blockers to NSAIDs, and found the new drugs were superior in effect. However, they have also found that anti-NGF formulations may be associated with an increase in symptom severity in patients with osteoarthritis when taken with NSAIDs. This interaction has resulted in the need for hip replacement in some cases. Therefore, NGF blockers may be used as an alternative for older drugs, pending full clinical development and approval. These drugs are associated with their own panel of side effects, including sensory abnormalities, however.

Glucosamine has also been investigated as another alternative treatment for hip pain and damage. This molecule is a variation on a natural amino acid and is associated with some benefits in cases of arthritis. It is also a component of cartilage. Glucosamine is currently available as a supplement linked to positive effects on joint movement and function in some markets. However, glucosamine was not associated with significant differences in the progression or severity of arthritis-related pain when investigated in clinical studies. Other research found this molecule was not associated with positive effects on joint function or movement. Therefore, glucosamine may not gain approval as an alternative therapy in the management of hip pain.

Conclusion

hipbulletHip pain may be a significant source of disability and debility. It may be associated with many conditions and risk factors. These include osteoarthritis, occupational hazards, various forms of tissue damage, and genetic disorders. Hip pain is popularly linked to more senior age groups, but may also affect younger people. This type of pain may be acute or persistent.

There are many treatment options for pain emanating from the hip region. These include conventional painkillers and nerve blocks. Disrupting the pain-signaling parts of spinal nerves using radiofrequency ablation is another therapy associated with effective relief of moderate duration. Spinal cord stimulation is another option that involves the implantation of a semi-permanent nerve-modulating device to inhibit pain signaling. Alternative forms of treatment include transcutaneous electrical stimulation. Hip replacement, or arthroscopy, is an option for patients in severe chronic pain related to osteoarthritis or osteoporosis.

Physical therapy is another important component of therapy for many patients who require an optimal return to normal performance or everyday activity following hip surgery or trauma. Emerging treatments with promising application to cases of hip pain include arthroscopy and NGF-blocking drugs. Education and training in the prevention of hip damage may also contribute to reductions in the risk of this type of pain in the future.

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