Note: This is a 3 part series on adult musculoskeletal hip pain. Part 1 will focus on location of and causes for hip pain, Part 2 will address physical examination of the hip and Part 3 will focus on treatment.
How many times have you had a patient present to your office with the chief complaint of hip pain? How a patient describes hip pain takes on a wide variety of meanings and locations, all of which mean different things to a healthcare provider. I find it is easiest, during the exam, to have patients point to the exact area of the hip where they are having pain. This helps me to pinpoint their actual problem and why they came to see me. Once I have this information, I mentally assign their complaints to anterior hip pain (groin pain), lateral hip pain or posterior hip pain (back pain). This approach allows me the focus better on their diagnosis and how best to treat their problem(s).
Anterior Hip Pain – Groin Pain
Anterior hip pain is often also called groin pain. Factors that affect anterior hip pain are trauma, age, activity level and associate factors. The history and physical exam will give you specific clues on injury type. Traumatic injuries to the hip can include fractures, muscle sprains and dislocations. A hip fracture or dislocation is best diagnosed with the help of x-ray but is fairly obvious by history and physical exam. These patients most often have suffered a traumatic event in order to sustain this type of injury. Typically, hip fractures and dislocations do not present to the office for initial exams. However, it is not uncommon for patients to present, to the office, with non-traumatic escalating groin pain and increasing difficulty bearing weight. If these patients are older, and or have known bone mineral deficiencies, providers should have a high suspicion for insuffiency or stress fracture of the hip. X-ray may not detect these type fractures and a CT scan or MRI may be necessary. A younger patient with similar complaints would be a good indication for avascular necrosis (AVN). Suspicion for AVN should be increased for a patient with anterior hip pain and has a history of chronic tobacco use, alcoholism, previous hip trauma, IV drug use, sickle cell disease, living at altitude or scuba diving. All of these factors can contribute to vascular compromise and therefore cause damage to the femoral articular surface. Degenerative joint disease/osteoarthritis are another cause for groin pain. These patients will have a slow progression of hip discomfort associated with a loss in range of motion (ROM). There is no inability to weight bear but may have pain associated with activity. X-ray will be helpful in determining the quality of joint arthritis or AVN. Musculoskeletal strains are commonly associated with the physically active. Sudden twists and turns are the usual causes of injuring the hip flexor muscles. These patients are younger and can reliably describe a specific motion or activity that caused their injury. Commonly the rectus femurs, illiopsoas and adductor muscle groups are injured. Pain is reproduced with hip flexion (both seated and supine), resistive adduction or passive abduction and with active and resistive hip rotation. Impingement syndrome/labrial injury of the hip can also limit motion and cause painful motion of the hip. Lastly, anterior hip pain can result from inguinal hernias and septic joints or toxic synovitis. Hernia is more often seen in the athletic population and the elderly. These patients will present with pain and swelling in the inguinal region. If a patient is suspected of having a hernia they should be referred to the general surgeon for evaluation. Hip infections are more commonly associated with the pediatric population. These patients usually have had a recent viral or bacterial illness that has potentially spread to the hip joint. If any patient is suspected to have a possible hip infection, they should be referred to the ER for urgent evaluation. (Look for an upcoming blog post on Septic arthritis vs. Toxic synovitis of the hip). Pelvic trauma, infection, ob-gyn or skin laceration can be potential causes for anterior hip pain
Lateral Hip Pain
Patients who complain of lateral hip pain are usually from a non-traumatic origin and localize tenderness over the greater trochanter. This best describes trochanteric bursitis. They typically describe pain sleeping on the affected side, pain getting in and out of chairs/cars, and have a popping feeling with going from seated to standing and vice verse. They are more often than not over-weight and sedentary. They also do not experience any radicular symptoms but may describe pain that runs along the lateral thigh and stops near Gerdy's tubercle. Aside for the possibility for fracture or skin infection, trochanteric bursitis is the primary cause for lateral hip pain in adults. However, lateral hip pain can also be a manifestation of a far lateral lumbar disc injury. A far lateral disc injury is a result of a disc rupture or bulge that presses on the lateral nerve root and causing referred pain along the lateral hip and goes into the groin. These patients can also complain of low back pain, leg weakness and sensory changes in the affected leg. Your physical examination will help to refine your diagnosis. Ultimately an MRI will help to definitively diagnosis this problem.
Posterior Hip Pain
Referred pain from the lumbar spine and associated nerves are the more common non-traumatic origin for posterior hip pain. Irritation of the sciatic nerve cause a radiation of pain into the buttocks in what is frequently described by patients as posterior hip pain. These patients are uncomfortable with sitting and lying down, movement makes them more painful and resting too long makes them equally uncomfortable. They may experience a dull ache or a sharp burning pain that runs down the leg to the level of the knee or into the foot. They may be in mild discomfort or excruciating pain. They may report weakness with leg or foot motions and have some sensory changes in the affected extremity. Patients with pelvic trauma, acetabulum fractures, hip dislocation, hip impingement/labrium tear, hamstring strain, degenerative hip joint and trochanteric bursitis can also present as posterior hip pain.
The location of a patient's hip complaint will give a provider better ideas as to the potential causes for that pain. Keep in mind that just because a patient localizes pain to one area of the hip does not exclude other causes for their pain. Patients can have more than one musculoskeletal problem at a time and may have pain that is perceived in various locations. Keeping in mind a wide differential diagnosis will help a provider better identify hip injuries.