The hip is a ball and socket joint allowing various leg movements. It is an essential weight-bearing joint (in the body) and is prone to different types of injuries, the most serious being dislocation or fracture. However, once the proper diagnosis is made, there are numerous types of effective treatments.
What are the structures that make up the hip joint?
The hip joint is a ball and socket joint made up of the femur (thigh bone), ilium (part of the pelvis), and the acetabulum. The part of the femur that inserts into the acetabulum is called the femoral head; both have cartilage (strong and flexible connective tissue) at the area where they meet.
Other hip structures consist of the tendons (connecting muscles to bones), ligaments (connecting bones to other bones), and bursa (fluid-filled sacs that function as cushions).
The complex arrangement allows different movements of the hip, including:
- Abduction involves moving the femur outwards at the side, while adduction moves the leg inward.
- Flexion consists of moving the leg forward, while extension consists of moving the leg backward.
- External rotation moves the toes outwards, while internal rotation moves the toes inwards.
What are non-traumatic causes of hip pain?
Osteoarthritis involves degenerative (wear and tear) changes in the hip caused by aging, use, and weight-bearing pressure. It is estimated that one in four adults will develop hip osteoarthritis and pain during their lifetime.
Rheumatoid Arthritis is an autoimmune disorder in which the body mistakes its own tissues for a foreign pathogen, like a bacteria or virus, and attacks itself.
Muscular strain can occur with stretching of the muscles or tendons, producing microfiber tears.
Septic arthritis occurs when an infection, from somewhere else, moves to a joint, seen in the hip for young and older people.
Hip bursitis results when the fluid-filled sacs, called bursa, become irritated and engorged with fluid. These bursae usually contain small amounts of fluid and cushion the joints.
Other causes of hip pain include referred pain from other areas, such as the low back and knee, along with various neuropathies (pain associated with the nerves).
What are some traumatic causes of hip injury and pain?
Fractures of the hip typically occur in the elderly after a fall. The most common fracture is a fracture of the femoral neck, which accounts for about ½ of all hip fractures. The femoral neck is the area of the femur 1-2 inches from the joint where the femoral head joins the acetabulum.
The hip labrum is a unique piece of cartilage that lines the hip joint, helping it absorb shock and disseminating pressure. Unfortunately, the labrum can become torn or detached from trauma, wear and tear, or hip osteoarthritis.
Hip dislocations occur either with trauma or after a hip replacement surgery (discussed below). They can be repositioned by traction, closed reduction, or by surgery, open reduction. A hip dislocation is a medical emergency that is time sensitive and must be treated as soon as possible.
What is the diagnostic workup for hip injury and pain?
A history is taken to learn about trauma, work, and recreational activities.
A physical exam evaluates areas of tenderness, swelling, and warmth.
Laboratory tests include a white blood cell level (WBCs) for infection, a rheumatoid factor for rheumatoid arthritis, and a serum uric acid for gout.
Plain x-rays should be done to evaluate for bony abnormalities, including fractures, osteoarthritis, spurs, or osteoporosis (bone thinning).
An x-ray from the front to the back, called an AP view, allows viewing of the hip and the low back. It helps the physician diagnose hip dislocation and fractures.
Computed tomography (CT) and magnetic resonance imaging (MRI) scans evaluate soft tissue structures not seen on x-rays, including the muscles, tendons, ligaments, and bursa.
What is the treatment for hip injury and pain?
If it is determined that the hip pain is from a stretching of the muscles, tendons, or ligaments, it can be treated conservatively, including:
- Medications such as acetaminophen (Tylenol) can help with the pain, while non-steroidal anti-inflammatory drugs (NSAIDs) can help with the inflammation.
- Physical therapy (PT) uses different modalities such as ice, heat, ultrasound, and electrical stimulation. Instructions can be given on specific home exercises. In addition, a physical therapist can provide proper education on the proper use of a cane or crutches.
- Chiropractic and acupuncture can provide significant relief in some people.
- Direct hip cortisone injections with a local anesthetic have proven effective, especially in the case of hip bursitis.
- Infections must be treated with oral or intravenous (IV) antibiotics.
- For rheumatoid arthritis, a special class of medications called disease-modifying antirheumatic drugs (DMARDs), such as methotrexate, can help with the condition.
- Osteoarthritis cannot be treated once it occurs, so the treatment is to prevent further disease advancement by correcting the issues causing the osteoarthritis.
What is the treatment for hip dislocation and fractures?
Depending on the type of fracture or dislocation, surgery may be necessary. Surgical metal pins can be used to stabilize the bones.
What is hip replacement surgery?
This type of surgery creates a new hip joint using various materials, including metal and ceramic parts.
The hip joint is a ball and socket joint that is important for weight bearing.
There are various causes of non-traumatic hip pain, including osteoarthritis, rheumatoid arthritis, strains, sprains, and septic arthritis.
Hip trauma can result in femur fractures or dislocation.
There are various conservative treatments in addition to hip replacement surgery using ceramic or metal parts to recreate the hip joint.
Ahuja, Vanita, Deepak Thapa, Sofia Patial, Anjuman Chander, and Anupam Ahuja, ‘Chronic Hip Pain in Adults: Current Knowledge and Future Prospective’, Journal of Anaesthesiology, Clinical Pharmacology, 36.4 (2020), 450–57 <https://doi.org/10.4103/joacp.JOACP_170_19>
Chamberlain, Rachel, ‘Hip Pain in Adults: Evaluation and Differential Diagnosis’, American Family Physician, 103.2 (2021), 81–89
Dawson-Amoah, Kwesi, Jesse Raszewski, Neil Duplantier, and Bradford Sutton Waddell, ‘Dislocation of the Hip: A Review of Types, Causes, and Treatment’, The Ochsner Journal, 18.3 (2018), 242–52 <https://doi.org/10.31486/toj.17.0079>
‘Septic Arthritis - Symptoms and Causes’, Mayo Clinic <https://www.mayoclinic.org/diseases-conditions/bone-and-joint-infections/symptoms-causes/syc-20350755> [accessed 16 September 2022]