A 32-year-old man presents to the Physical Medicine and Rehabilitation (PM&R) clinic with right hip pain. He describes that the pain is gradually worsening over the last 3 months and located deep in the groin. He has had intermittent groin pain for more than 1 year and denies any preceding injury or trauma. The pain is worse with prolonged walking and playing soccer in the weekend. He stopped playing soccer 2 months ago. He takes over-the-counter acetaminophen and ibuprofen with temporary relief. There is intermittent posterior thigh pain in the right side as well. He reports his sleep is disturbed because of this pain. He denies numbness, tingling, focal weakness, “giving way” sensation, or recurrent falls. He reports intermittent knee pain in the right side and intermittent midline lower lumbar pain. He was referred by his primary care doctor.
Past medical history: He denies any significant past medical history, including hypertension, diabetes, increased cholesterol, developmental delays, or pediatric orthopedic conditions.
Social history: He works as a civil servant, lives with wife in 3rd-floor apartment with elevator. He continues to jog (about 20 miles per week) in the community park but stopped playing soccer during weekend because of pain.
Past surgical history: None
Allergies: No known drug allergy
Medications: Occasional ibuprofen 400 mg
BP: 130/76 mmHg, RR: 16/min, PR: 75 per min, Temp: 97° F, Ht: 5’8”, Wt: 164 lbs, BMI: 24.9 kg/m 2
General: Well built, not in acute distress. He is alert and oriented to person, place, and time.
Extremities: No edema, no skin rashes, no erythema, no surgical scars, no open wound.
Inspection of lower extremity: No gross deformity. No gross muscle atrophy.
Range of motion of lumbar spine: Within functional limits.
Motor exam: 5/5 symmetrically except right hip flexion, and extension which is pain limited to 5‒/5.
Deep tendon reflexes: 2+ in quadriceps femoris and triceps surae bilaterally.
Sensory exam: Intact to light touch and pinprick in all dermatomes of both lower extremities.
Straight leg raise test: Negative
Slump test: Negative
Patrick (flexion, abduction, and external rotation) test: Reproducing groin pain.
Pace maneuver (for piriformis syndrome): Negative.
Flexion, adduction, and internal rotation (FAIR): Pain in the groin.
Ely test: Tight rectus femoris in the right side.
Modified Thomas test: No significant hip flexion contracture noted. Symmetric.
No tenderness on the greater trochanter.
Posterior superior iliac spine: Not tender.
General Discussion: General Approach to Hip Pain
The initial focus should be to differentiate local musculoskeletal conditions, such as intra- or extraarticular hip joint complex pathologies and also from other referred pain generators, such as lumbar spine or sacroiliac joint pathologies. Although both conditions coexist frequently, it is better to identify the primary or predominant pain generator for effective management.
The demographic information, such as age, gender, and detailed information of the groin pain (particularly the location of pain, mechanism of injury, aggravating and relieving factor) can be useful in narrowing down the differential diagnoses. Review of system and past medical history also provide valuable information.
Local musculoskeletal pathologies can be grouped based on the location of the pain, as illustrated in Table 6.1 . In this table, the groin region was divided based on the groin triangle, defined by anterior superior iliac spine, pubic tubercle, and midline between the anterior superior iliac spine and superior pole of the patellar. Characteristics of the pain can be useful to differentiate the neuropathic versus musculoskeletal (nociceptive) pain. This patient does not have typical radiating pain from the lower back to the groin nor sensory symptoms, favoring the local musculoskeletal pathologies for pain generator. The young age of the patient argues against degenerative osteoarthritis (OA); however, it cannot be ruled out.
|Pathologies and Characteristics
|Rectus abdominis insertional tendinopathy
|Femoral neck fracture: pain on internal rotation/hopping, often significant trauma history missing in osteoporotic elderly or stress fracture with underlying risk factors
|Trochanteric bursitis, gluteal tendinopathy/tear, proximal iliotibial band syndrome and Morel-Lavallee lesion
|Meralgia paresthetica; with minor trauma/irritation (e.g., belt or weight loss or gain)
|Medial (pubic tubercle)
|Pubic bone stress injury (osteitis pubis), degenerative pubic symphysis: worsening pain with stair climbing
|Inferior ramus bony injury (including stress fracture): worse with hopping
Rectus abdominis enthesopathy
|Adductor/gracilis avulsion/enthesopathy/tendinopathy at musculotendinous junction
|External iliac A endofibrosis: reproducible thigh discomfort after high-intensity exercise (e.g., cycling)
|In groin triangle
|Iliopsoas tendinopathy/tear, iliopectineal bursitis
|Rectus femoris calcific tendonitis, musculotendinous junction tear
Femoroacetabular impingement/labral pathology: younger adults
Slipped femoral epiphysis: in adolescents
Avascular necrosis with medical comorbidities and Legg-Calve-Perthes disease (children aged <12 years)
|Genitofemoral and medial femoral cutaneous nerve lesion: neuropathic pain
Femoral hernia: painful lump inferomedial to pubic tubercle
The physical examination can focus on the neuromuscular examination, including inspection for atrophy of muscles, evaluation of focal motor (weakness of muscle with/without deformity [indicating chronic imbalance of muscle strength]) or sensory deficit (sensation to large fiber mediated light touch and proprioception and small-fiber mediated pinprick and temperature sensation) in each dermatome or peripheral nerve distribution, as well as deep tendon reflexes. Focal neurologic deficit in the groin region can be explained by pathologies involving lumbar roots (L1–3), lumbar plexus, and its branches, such as iliohypogastric, ilioinguinal, genitofemoral mononeuropathies, or pathologies involving muscles (myopathy, polymyalgia rheumatica, possibly pelvic floor dysfunction with functional deficit). Occasionally, referred pain from musculoskeletal pathologies (e.g., facet joint mediated pain or myofascial pain syndrome) can be perceived as positive sensory symptoms.
Common Differential Diagnoses for Hip Pain
Hip osteoarthritis —OA of the hip joint is common especially in the older population with prevalence of radiographic findings of hip OA up to 27%. It is more common in females than males, Caucsians and African Americans. The pain from OA is often vague, most commonly in the groin but can be around the hip joint (anterior, lateral, and posterior aspect [buttock pain, up to 71% of people with hip OA]) possibly with referred leg pain. , The onset of pain is usually insidious without any preceding injury or trauma and frequently accompanied by morning stiffness (<1 hour). The pain is aggravated by prolonged standing, walking, stair negotiation, or any prolonged weight-bearing activity. However, this is not specific to OA
Femoroacetabular impingement —a problem among active younger and middle age population, hip (femoroacetabular) joint impingement secondary to abnormal morphology (femoral head-neck junction and/or acetabulum). Because there is high prevalence of these morphological abnormalities among asymptomatic young population, it is often challenging to correlate this abnormal morphology to patient’s symptom. The presentation seems to be similar to hip OA with groin pain and buttock pain, but can be in the lower back, anterior thigh, and knee pain. The “C-sign,” forming the letter C with one’s hand with the index at the anterior superior iliac spine (ASIS) and thumb toward the posterior superior iliac spine (PSIS) with the palm over the lateral hip on description of the location of the pain is historically classic for femoral acetabular joint pathology (such as impingement syndrome) but the overall diagnostic utility of this sign/aspect of the history is questionable. There are often concomitant (or secondary to femoroacetabular impingement) pathologies, such as labral tear or chondral defect/delamination seen on advanced imaging that can complicate the picture. Activities requiring flexion of the hip (crouching or sitting) or athletic activities are limited with pain. The symptoms can be reproduced by impingement position, such as flexion, adduction, and internal rotation (FADIR) of the hip joint.
Inflammatory arthropathies —presents with groin, trochanteric, and/or buttock pain, often associated with prolonged stiffness. The pain often gets better with activity. Multiple/bilateral joint involvement, fatigue, and other systemic symptoms are common. There is a variation of hip joint involvement between different inflammatory arthropathies. For example, ankylosing spondylosis commonly involves hip joint (<50%) with lower back/buttock pain, but psoriatic arthropathy and gout rarely affects the hip joint.
Labral tear —can be present on advanced imaging without any symptoms, therefore it is often difficult to correlate the imaging finding to the patient’s presentation. Reproduction of symptoms with the impingement of the specifically located labrum in the context of the relevant history is supportive of the labral tear as the pain generator. Response from diagnostic hip joint injection can be helpful as well. Most susceptible location is the anterosuperior labrum because of stress during hip flexion and internal rotation frequently happening during pivoting activities. Patient may present with “pop” along with catching sensation, pain in the groin or buttock depending on the location of the labrum.
Avascular necrosis —if there are risk factors, such as history of trauma, radiation, sickle cell disease, steroid use, alcohol abuse, and so on, avascular necrosis should be included in differential diagnosis. Peak incidence is between second to fifth decades of life (most common in mid-30s), more common in males than females (varies depending on studies with equivalence in gender prevalence in some studies), and often bilateral (40%–80%). Pain is often insidious at onset, gradually worsening, and becomes constant eventually. Weight-bearing activity and range of motion (ROM) of the hip joint (particularly internal rotation) can be painful with limitation. As the presentation is similar to other hip joint pathologies, a high index of suspicion is required and this can often be obtained from the risk factors elicited in the history. This allows for the appropriate imaging study to be ordered for diagnosis. One should remember that early stages of avascular necrosis (without femoral head collapse) can be missed on plain radiographs (with sensitivity as low as 41%).
Strains and sprain —if there was a preceding trauma and injury, strains and sprains can be suspected for the underlying etiology after fracture is ruled out. Frequently, the imaging studies are negative other than avulsion injury at the insertion site. Depending on the mechanism of injury and location of pain, the localization of the muscle injury can be easily done if the time is taken to isolate the various muscles about the hip much in the same way one does with the rotator cuff in the shoulder. In significant muscle strains or tear, ecchymosis can occur. Examination can be nonspecific but tenderness and reproduction of symptoms with muscle/tendon/ligament stretching (or resistive strengthening) can help to identify the lesion. Typically, there is no neurologic symptom other than irritation of cutaneous nerve (by overlying/neighboring tendon or ligament).
Trochanteric bursitis (greater trochanteric pain syndrome) —one of the most common sources of pain in the hip, prevalence up to 5.6 per 1000, more common in females than males, and peak incidence in fourth to sixth decades. Bursitis can occur with/without any preceding injury or trauma. Other risk factors include leg-length discrepancy, pelvic obliquity, running on banked surface, and obesity. The pain is typically located in the slightly posterior aspect of the greater trochanter (where subgluteus maximus bursa located). A gluteus medius tendinopathy, tear, or avulsion may produce point tenderness in a similar area. The patient often complains of difficulty sleeping on the symptomatic side. About 50% of patients report the pain along the lateral thigh. Pain is worse with stair climbing and prolonged walking.
Other bursitis —pain from iliopsoas bursitis is located anteriorly (in the groin) and pain from ischiogluteal bursitis is located posteriorly (buttock) typically; however, diffuse or poorly localized deeply situated pain is also not uncommon.
Iliopsoas bursitis pain is aggravated by the movement involving hip flexion, such as climbing stairs and standing from a sitting position. Snapping with/without pain can occur with hip joint movement. The pain may radiate down to the thigh or to the knee.
Ischiogluteal bursitis can be aggravated by sitting (especially on hard surface) and more common in the person with lean body mass. There is increased friction between the ischial tuberosity and skin in the lean person at sitting because of upward sliding of gluteus maximus muscle surrounding ischiogluteal bursa while sitting.
Stress fracture —recent increase in activity can raise the suspicion for stress fracture. If there are risk factors, including female athletic triads (irregular menstruation [or amenorrhea], eating disorders, and osteoporosis), or suboptimal biomechanics (leg length discrepancy, coxa vara, etc.), there should be low threshold for imaging study and further workup. Pain is gradual in onset, often located in the groin associated with weight-bearing activity. However, pain can be present at night. Pain is reproduced by extreme range, and hopping (on one leg) and fulcrum test. Often the physical examination is not specific. Once identified, it is important to localize the stress fracture for the management and prognosis. The trabecular pattern of the proximal femur is uniquely arranged to manage forces with medial trabecular system for vertical compressive forces and lateral trabecular system for shear forces of body weight and ground reaction force (therefore high likelihood of nonunion requiring surgical intervention).
Lumbar spondylosis —pain from the facet arthropathy from lumbar spondylosis is very common in elderly population. It is located in the midline lower lumbar region, with intermittent referred pain to the buttock and groin. The pain is worse with activity requiring trunk (lumbar) extension and rotation. Flexion of lumbar spine is better tolerated than extension. Neurologic symptoms other than positive sensory symptoms (pain and tingling) are less common; however, they can be seen in the distribution of nerve root that is compromised in the setting of lumbar spondylotic stenosis (with narrowing of neural foramen).
Discogenic pain with radiculopathy —acute disc herniation at lumbar spine can lead to nerve root compression at this level. Although it is not as common as L5‒S1 radiculopathy, it can occur when the lower lumbar spine is less mobile because of degenerative changes or fusion. It is difficult to differentiate the symptoms from L2‒L3 radiculopathy versus lumbar radiculoplexus neuropathy (amyotrophy). Lumbar radiculoplexus neuropathy is typically diagnosed as radiculopathy initially and found in 1% of diabetic patients. It involves femoral and sciatic nerves, progresses to the contralateral side , and is associated with weight loss. In both cases, the pain can be severe initially. In radiculoplexus neuropathy, the pain can subside as significant weakness follows.
Malignancy —if the patient has history of cancer, malignancy (metastatic cancer) should be included as differentials until it is ruled out. It presents with worsening pain at night, in supine position and becomes constant. Systemic manifestation such as weight loss, malaise, fatigue may accompany. When ordering magnetic resonance imaging (MRI), contrast should be added when possible to help further characterize lesions.
Septic arthritis/osteomyelitis —more common in pediatric population and relatively uncommon in adults (approximate incidence of 4.6 per 100,000). Initially, the presentation can be nonspecific with pain, painful limitation in ROM, and malaise. With risk factors such as drug abuse, hemoglobinopathy, or immunocompromised states, a high index of suspicion is required.
This patient was an active young adult with insidious onset of hip pain over a few months suggesting chronic nature of conditions. It makes acute traumatic or vascular injury less likely as underlying etiology. Lack of focal neurologic deficit and temporary response to the nonsteroidal antiinflammatory drugs (NSAIDs) suggests musculoskeletal pathologies rather than neurologic disorders. Musculoskeletal pathologies can be divided into the local musculoskeletal pathologies versus distant pathologies causing referred pain to hip (such as lumbar spine, sacroiliac joint complex pathologies, etc.). Among the local pathologies, based on the location of maximal pain and tenderness, the differentials can be further narrowed down (see Table 6.1 ). Degenerative hip OA is less common in this patient’s age group. Considering active lifestyle and sports participation, tendinopathy, strain, sprain, bursitis, chondral, labral, pathology, or other mechanical joint pathology (such as femoroacetabular impingement syndrome) can be considered as the underlying etiology. Intermittent posterior thigh and knee pain indicates either concomitant knee pathology or local hip pathology with referred pain.
It is important to recognize the red flags and order imaging and serologic tests if indicated (e.g., to evaluate inflammatory arthropathies, connective tissue disorders, infections, or tumor/cancer). If there is a reasonable suspicion, then further imaging may be required when the initial imaging findings did not reveal anything.