Musculoskeletal

Hip pain in adults: differential and workup

Clinical Overview and When to Suspect Hip Pathology in Adults

— Anterior/groin pain → true intra-articular hip (osteoarthritis, labral tear, femoroacetabular impingement, osteonecrosis, occult fracture, septic arthritis)

— Lateral pain → greater trochanteric pain syndrome (gluteus medius/minimus tendinopathy, trochanteric bursitis), iliotibial band

— Posterior/buttock pain → lumbar radiculopathy, SI joint dysfunction, piriformis syndrome, ischiogluteal bursitis, vascular claudication

— Fever, monoarticular swelling, inability to bear weight → septic arthritis until proven otherwise

— Antecedent trauma in elderly patient with shortened/externally rotated leg → hip fracture, even with negative initial X-ray

— Chronic steroid use, alcoholism, sickle cell, lupus, post-transplant → avascular necrosis of femoral head

— Unintentional weight loss, night pain, history of malignancy → metastatic disease (breast, prostate, lung, renal, thyroid)

— Saddle anesthesia, bowel/bladder dysfunction → cauda equina

Step 3 management: Most atraumatic, afebrile hip pain in an ambulatory adult without red flags can begin with a focused history, exam, and weight-bearing AP pelvis + frog-leg lateral X-ray; advanced imaging is reserved for diagnostic uncertainty, persistent symptoms beyond 4–6 weeks, or pre-procedural planning.

Board pearl: "Hip pain" reported by the patient that is felt in the buttock or lateral thigh is more often spine or bursa, not joint — true hip joint pathology classically localizes to the groin.

Hip pain in adults is a common ambulatory complaint that spans degenerative, inflammatory, infectious, traumatic, neoplastic, and referred etiologies — the Step 3 task is to localize, triage, and risk-stratify rather than reflexively image.

Anatomic localization narrows the differential dramatically:

Red flags that mandate urgent workup:

Epidemiology shapes pretest probability: hip OA prevalence rises sharply after age 50; femoroacetabular impingement and labral tears predominate in younger active adults; transient osteoporosis of the hip occurs in third-trimester pregnancy and middle-aged men.

Presentation Patterns and Key History

— Onset: acute traumatic (fracture, dislocation), subacute (septic, crystal, AVN), insidious (OA, tendinopathy, metastasis)

— Provocation: weight-bearing pain → mechanical/structural; rest and night pain → infection, tumor, inflammatory; pain with prolonged sitting and rising → FAI or labral tear; pain lying on the affected side → trochanteric bursitis

— Quality: deep aching groin → intra-articular; sharp catching/clicking → labral tear; burning radiating down posterolateral leg → radiculopathy

— Stiffness pattern: morning stiffness <30 min → OA; >1 hour with bilateral symptoms → inflammatory arthritis (RA, spondyloarthropathy); inflammatory back pain in young man with alternating buttock pain → ankylosing spondylitis

— Difficulty putting on socks/shoes, getting in/out of a car → classic for hip OA

— Inability to bear weight → fracture, septic joint, severe AVN

— Antalgic gait with shortened stance phase → mechanical hip pathology

— Corticosteroid courses, alcohol use, SLE, sickle cell, HIV antiretrovirals → AVN

— IV drug use, recent bacteremia, prosthetic joint → septic arthritis or prosthetic joint infection

— Recent endurance running, military recruit, RED-S/female athlete triad → femoral neck stress fracture (high-risk tension-side fracture)

— Anticoagulation + minor trauma in elderly → occult fracture or iliopsoas hematoma

— Pregnancy or postpartum → transient osteoporosis, pubic symphysis dysfunction, sacroiliitis

Key distinction: Groin pain worsened by activity and relieved by rest in an older adult points to hip OA; groin pain worse at night and at rest in a steroid user points to AVN — the timing flip is the test-writer's lever.

Board pearl: Always ask about knee pain — pediatric and adult hip pathology (slipped capital femoral epiphysis in adolescents, hip OA in adults) classically refers to the ipsilateral knee via the obturator nerve.

Frame the history around OPQRST plus functional impact, because Step 3 vignettes hinge on subtle pattern recognition:

Functional questions reveal severity and direct disposition:

High-yield history elements:

Medication and social history: bisphosphonate use >5 years with prodromal thigh pain → atypical femoral fracture (subtrochanteric, transverse).

Physical Exam Findings and Functional Assessment

— Antalgic gait (shortened stance) → painful weight-bearing source

— Trendelenburg gait (pelvis drops on swing side) → weak ipsilateral hip abductors (gluteus medius), seen in gluteal tendinopathy, L5 radiculopathy, post-THA

— Shortened, externally rotated leg at rest → displaced femoral neck fracture

— Forward-flexed posture → hip flexion contracture from advanced OA

— Normal: flexion ~120°, internal rotation ~35°, external rotation ~45°, abduction ~45°

— Loss of internal rotation is the earliest and most sensitive sign of hip OA

— Capsular pattern: IR > extension > abduction lost first

— FADIR (Flexion, ADduction, Internal Rotation) → anterior impingement/labral tear

— FABER/Patrick (Flexion, ABduction, External Rotation, "figure-4") → SI joint, posterior hip, or intra-articular pathology

— Stinchfield (resisted straight-leg raise) → intra-articular hip pain

— Ober test → IT band tightness

— Thomas test → hip flexion contracture

— Log-roll → most specific for intra-articular pathology (isolates capsule)

— Tenderness over greater trochanter with pain lying on side → greater trochanteric pain syndrome

— Ischial tuberosity tenderness → hamstring origin or ischiogluteal bursitis ("weaver's bottom")

— Pubic symphysis tenderness → osteitis pubis (athletes, postpartum)

Step 3 management: In an elderly patient with hip pain, inability to bear weight, and a leg that is shortened and externally rotated, immediately immobilize, place NPO, obtain AP pelvis + cross-table lateral, type and screen, basic labs, ECG, and consult orthopedics — do not delay for advanced imaging if X-ray is diagnostic.

Board pearl: A patient with hip pain whose pain is not reproduced by any hip ROM or palpation maneuver likely has referred pain from the lumbar spine, retroperitoneum, or pelvis — examine the back, abdomen, and do a hernia/GU exam.

Inspection and gait before touching the patient:

Range of motion (compare bilaterally, supine):

Provocative maneuvers:

Palpation:

Neurovascular: assess distal pulses, sensation, strength, and straight-leg raise to screen for lumbar radiculopathy mimicking hip disease.

Diagnostic Workup — Initial Labs and Imaging

— Weight-bearing AP pelvis (both hips on one film for comparison) + frog-leg or cross-table lateral of the symptomatic hip

— Look for: joint space narrowing (superior > medial in OA), subchondral sclerosis, osteophytes, subchondral cysts, femoral head sphericity, cam/pincer morphology, lytic/blastic lesions, fracture lines, crescent sign (AVN), pubic symphysis widening

— Fever, effusion, or atraumatic monoarthritis → CBC, ESR, CRP, blood cultures × 2, urgent arthrocentesis under fluoroscopy/US (hip is deep — image-guided)

— Synovial fluid: WBC >50,000/µL with >75% PMNs suggests septic arthritis; crystals for gout/CPPD; Gram stain and culture

— Inflammatory pattern suspected → RF, anti-CCP, ANA, HLA-B27 (if spondyloarthropathy features), uric acid

— Suspected metastasis → CBC, CMP, calcium, alkaline phosphatase, PSA in men, SPEP/UPEP, age-appropriate cancer screening review

— Suspected AVN risk factors → lipid panel, coagulation studies if recurrent, HIV testing if antiretroviral exposure

CCS pearl: For a suspected septic hip on CCS, the order set is: IV access, blood cultures × 2, CBC, ESR, CRP, lactate, fluoroscopy- or US-guided hip aspiration, empiric IV vancomycin + ceftriaxone after cultures, orthopedic surgery consult for urgent washout — do not give antibiotics before aspiration unless the patient is septic.

Key distinction: CRP rises and falls faster than ESR — CRP is the better marker to track response to therapy in septic arthritis and prosthetic joint infection.

First-line imaging for nearly all adult hip pain:

Radiographic OA grading: Kellgren–Lawrence 0–4; correlation with symptoms is imperfect — treat the patient, not the film.

Labs are guided by red flags, not routine:

ECG: not routine for hip pain, but obtain preoperatively in any patient heading to hip fracture surgery or those with cardiovascular risk factors and acute hip pathology — Step 3 perioperative thinking.

Pre-op labs for hip fracture: CBC, BMP, coags, type and screen, ECG, CXR if indicated; address anticoagulation reversal early.

Diagnostic Workup — Advanced and Confirmatory Studies

— Occult/stress fracture of the femoral neck when X-ray is negative but suspicion is high (elderly fall, runner with groin pain) — MRI within 24–72 hours; sensitivity approaches 100%

— Avascular necrosis (AVN) staging: MRI detects early pre-collapse disease before X-ray changes; the "double-line sign" on T2 is pathognomonic

— Labral tear and FAI: MR arthrography is the gold standard

— Soft tissue masses, marrow infiltration, osteomyelitis, transient osteoporosis of the hip (diffuse marrow edema without focal lesion)

— Better delineation of complex fractures (acetabular, posterior wall), pre-operative planning

— Suspected pelvic ring injury after high-energy trauma

— When MRI is contraindicated (pacemaker, severe claustrophobia)

— Useful when MRI unavailable and stress fracture suspected

— Whole-body screen for metastatic bone disease or Paget disease (look for elevated alk phos with normal calcium)

— Guides hip joint aspiration and injection (hip is too deep for blind tap)

— Evaluates trochanteric bursitis, gluteal tendon tears, iliopsoas tendinopathy/snapping hip

Board pearl: A patient on bisphosphonates >5 years with prodromal thigh or groin pain needs bilateral femur X-rays — atypical femoral fractures are often bilateral, and finding a contralateral incomplete fracture changes management to prophylactic fixation.

Step 3 management: Negative hip X-ray in an elderly faller who cannot bear weight does not rule out fracture — obtain MRI (preferred) or CT within 24–48 hours and keep the patient non–weight-bearing in the interim.

MRI of the hip is the most versatile advanced study:

CT indications:

Bone scan (Tc-99m):

Ultrasound:

DEXA scan: any adult >50 with a low-energy hip fracture, or postmenopausal woman/man >70, or earlier with risk factors — fragility fracture defines osteoporosis clinically regardless of T-score.

Diagnostic intra-articular lidocaine injection: pain relief after fluoroscopic injection confirms intra-articular source — useful when hip vs. spine is unclear.

Risk Stratification and First-Line Management Logic

— Surgical emergency: septic arthritis, displaced femoral neck fracture, cauda equina with hip referral, acute hip dislocation → ED transfer, ortho consult, NPO

— Urgent (24–72 h): occult fracture suspected, AVN with risk factors, suspected malignancy, prosthetic joint infection

— Subacute outpatient workup: chronic OA, FAI/labral tear, tendinopathy/bursitis, SI joint, radiculopathy

— Watchful waiting + conservative: nonspecific mechanical pain, mild OA, soft-tissue strain

— Patient education + weight loss (5–10% reduction meaningfully reduces symptoms)

— Land- or aquatic-based exercise + physical therapy focused on hip abductor/core strengthening — strongly recommended first-line

— Assistive devices (cane in contralateral hand)

— Topical or oral NSAIDs (lowest effective dose, shortest duration)

— Intra-articular corticosteroid injection (image-guided) — limited durability, 4–12 weeks relief

— Total hip arthroplasty when conservative measures fail and quality of life is impaired

— Tension-side (superior cortex) → high-risk → urgent surgical fixation

— Compression-side (inferior cortex) → protected weight-bearing, address energy availability, calcium/vitamin D

Step 3 management: For symptomatic hip OA failing conservative therapy, refer for total hip arthroplasty when daily function, sleep, or mobility are significantly impaired — there is no benefit to delaying when nonoperative options are exhausted, and outcomes are best in patients with good preoperative function.

Key distinction: Cane in contralateral hand offloads up to 40% of hip joint force; ipsilateral cane use is biomechanically incorrect.

Triage hip pain into four management buckets:

Hip OA conservative ladder (per ACR/AAOS):

Trochanteric bursitis / GTPS: activity modification, NSAIDs, PT for abductor strengthening, side-lying modifications; corticosteroid injection if refractory.

Femoral neck stress fracture:

Suspected AVN: protect from weight-bearing, address risk factors (taper steroids if possible, alcohol cessation); pre-collapse disease may respond to core decompression; post-collapse usually needs THA.

Pharmacotherapy — First-Line Drug Regimen

— Topical NSAIDs (diclofenac gel): strongly recommended for knee OA; reasonable adjunct for hip though penetration is limited by depth

— Oral NSAIDs are first-line systemic therapy: ibuprofen 400–600 mg TID, naproxen 250–500 mg BID, or celecoxib 100–200 mg daily

— Use shortest duration and lowest effective dose; co-prescribe a PPI if age >65, history of PUD, concurrent anticoagulant/antiplatelet, or chronic use

— Acetaminophen up to 3 g/day: modest effect; useful when NSAIDs contraindicated

— Duloxetine 30–60 mg daily: conditionally recommended for chronic OA pain, especially with comorbid depression or central sensitization

— Tramadol: conditional recommendation; avoid traditional opioids for OA — they show no superiority over NSAIDs and carry dependence risk

— eGFR <30, decompensated CHF, active GI bleed, recent CABG (absolute for nonselective COX inhibitors)

— Concomitant ACEi/ARB + diuretic ("triple whammy") → AKI risk

— Anticoagulation → bleeding risk; prefer celecoxib + PPI if NSAID essential

— Limit to 3–4 per year per joint; transient hyperglycemia in diabetics

— Recent data: avoid IA steroid within 3 months of planned THA (infection risk)

Board pearl: Chronic opioids for hip OA worsen long-term outcomes and delay appropriate referral for arthroplasty — Step 3 favors multimodal non-opioid analgesia + early surgical referral when function is impaired.

Hip OA analgesic ladder (ACR 2019, AAOS):

NSAID contraindications and cautions:

Intra-articular corticosteroid (e.g., triamcinolone 40 mg or methylprednisolone 40 mg with lidocaine, image-guided):

Hyaluronic acid injections: not recommended for hip OA (ACR strong recommendation against).

Crystal arthropathy of the hip: oral colchicine, NSAIDs, or short prednisone taper for acute flare; allopurinol for chronic gout once flare resolves, titrated to urate <6 mg/dL.

Septic arthritis empiric therapy: IV vancomycin + ceftriaxone (covers MRSA, streptococci, gonococci, gram-negatives); narrow based on culture; duration 2–4 weeks IV then PO transition per ID.

Procedural and Surgical Management

— Indications: refractory pain, functional limitation, failed 3–6 months of conservative therapy

— Approaches: posterior (most common, slightly higher dislocation risk), anterior (faster early recovery, learning curve), lateral

— Outcomes: >90% 15-year implant survival; among most successful elective surgeries in medicine

— Femoral neck fracture (intracapsular):

— Nondisplaced/valgus impacted → percutaneous screw fixation

— Displaced in elderly (>65) → hemiarthroplasty or THA (THA preferred in active, cognitively intact patients per recent HEALTH trial)

— Displaced in young patient → urgent ORIF to preserve native head (<24 h to reduce AVN)

— Intertrochanteric fracture (extracapsular): sliding hip screw or cephalomedullary nail

— Subtrochanteric fracture (think atypical femoral fracture): cephalomedullary nail

— VTE prophylaxis: LMWH, fondaparinux, apixaban, or rivaroxaban × 10–35 days

— Multimodal analgesia: acetaminophen, NSAIDs (cautiously), regional blocks (fascia iliaca, femoral nerve)

— Early mobilization POD #1, geriatric co-management ("orthogeriatric" model reduces mortality)

— DEXA + osteoporosis treatment initiation before discharge

CCS pearl: For a hip fracture patient, advance the clock to surgery quickly — order type and screen, ECG, CXR, BMP/CBC/coags, reverse anticoagulation, IV fluids, fascia iliaca block for analgesia, VTE prophylaxis after surgery, and geriatrics consult. Avoid skin traction (no benefit, harm risk).

Total hip arthroplasty (THA) is the definitive treatment for end-stage hip OA, AVN with collapse, and select fractures:

Hip fracture surgical decision tree:

Timing: hip fracture surgery within 24–48 hours reduces mortality, delirium, pressure ulcers, and pneumonia — coordinate with anesthesia, geriatrics, cardiology for risk assessment; do not routinely delay for asymptomatic findings.

Perioperative bundles:

Hip arthroscopy: labral repair, FAI debridement in young active patients with mechanical symptoms.

Core decompression: pre-collapse AVN (Ficat I–II) to delay or avoid THA.

Special Populations — Elderly and Renal/Hepatic Impairment

— Hip fracture carries 20–30% one-year mortality in patients >65; functional decline is permanent in ~50%

— Address polypharmacy (Beers criteria): avoid NSAIDs, muscle relaxants (cyclobenzaprine), long-acting benzodiazepines, anticholinergics in elderly with hip pain

— Falls workup post-hip pain: orthostatic vitals, medication review, gait/balance, vision, vitamin D level, home safety

— Delirium prevention after hip fracture: minimize tethers (Foley, restraints), early mobilization, sleep hygiene, avoid deliriogenic meds, treat pain adequately (under-treated pain is itself a delirium trigger)

— Initiate bisphosphonate (alendronate, risedronate) or zoledronic acid IV yearly before discharge or within weeks

— Calcium 1200 mg/day (preferably dietary), vitamin D 800–1000 IU

— In severe osteoporosis or after recurrent fracture: anabolic agents (teriparatide, abaloparatide, romosozumab) preferred first

— Treatment after fragility fracture is secondary prevention, not screening — do not require DEXA confirmation

— Avoid NSAIDs if eGFR <30; cautious if 30–60

— Acetaminophen safe (dose-adjust if cirrhotic)

— LMWH dose-adjust if CrCl <30; consider unfractionated heparin or apixaban

— Gadolinium MRI: avoid group I agents if eGFR <30 (NSF risk)

— Acetaminophen max 2 g/day in chronic liver disease

— Avoid NSAIDs in cirrhosis (renal hypoperfusion, variceal bleeding)

— Opioids: reduce dose, prefer hydromorphone or fentanyl; avoid codeine, tramadol (variable metabolism)

Step 3 management: Every patient ≥50 with a low-energy hip fracture should leave the hospital with (1) an osteoporosis medication started or scheduled, (2) calcium/vitamin D, (3) DEXA ordered, and (4) PCP follow-up within 1–2 weeks — failure to do so is a documented quality gap.

Board pearl: Patients on long-term PPIs have a modestly increased hip fracture risk; reassess PPI indication annually.

Geriatric considerations:

Osteoporosis after fragility fracture ("FLS — Fracture Liaison Service" model):

Renal impairment:

Hepatic impairment:

Special Populations — Pregnancy, Athletes, and Other Subgroups

— Transient osteoporosis of the hip: third-trimester or early postpartum groin pain, antalgic gait, normal X-ray initially; MRI shows diffuse marrow edema without focal lesion; self-limited over 6–12 months; protected weight-bearing, analgesia, monitor for fracture

— Pubic symphysis dysfunction / pelvic girdle pain: ligamentous laxity from relaxin; treated with PT, pelvic belt, acetaminophen

— Sacroiliitis flare in patients with axial spondyloarthropathy may worsen peripartum

— Imaging in pregnancy: prefer ultrasound and MRI without gadolinium; if X-ray needed, shield abdomen — single AP pelvis exposes fetus to ~1 mGy (below threshold)

— Femoroacetabular impingement (FAI): cam (femoral) or pincer (acetabular) morphology causing labral tears; treated with PT, activity modification, hip arthroscopy if refractory

— Femoral neck stress fracture: in runners, military recruits, female athlete triad / RED-S (low energy availability, menstrual dysfunction, low BMD) — high-risk tension-side fractures need urgent fixation

— Athletic pubalgia ("sports hernia"): groin pain with cutting/twisting in soccer/hockey players; rectus abdominis–adductor longus aponeurosis injury

— Snapping hip syndrome: internal (iliopsoas over iliopectineal eminence) or external (IT band over greater trochanter)

— New pain after THA → rule out prosthetic joint infection (ESR/CRP, joint aspiration with cell count + culture; alpha-defensin if available), loosening, periprosthetic fracture, dislocation

— Bacteremia from any source in THA patient warrants careful evaluation

Key distinction: Transient osteoporosis of the hip is reversible and self-limited; AVN progresses to collapse — both can appear similar on early MRI, but transient osteoporosis lacks a focal subchondral lesion and double-line sign.

Pregnancy and postpartum:

Young athletes:

Sickle cell disease: high AVN risk — bilateral hip MRI surveillance in symptomatic patients

Post-transplant / chronic steroid users: AVN can develop within months; threshold for MRI should be low

Patients with prosthetic hips:

Complications and Adverse Outcomes

— VTE/PE: leading preventable cause of post-op death; prophylaxis 10–35 days

— Delirium: 30–50% of elderly hip fracture patients; multifactorial

— Pressure ulcers: prevent with early mobilization, repositioning, support surfaces

— Pneumonia and UTI: incentive spirometry, prompt Foley removal

— Anemia: blood loss + hemodilution; transfuse for hemoglobin <7 (or <8 with cardiac disease)

— AVN of femoral head: ~10–30% after displaced femoral neck fracture, especially with delayed fixation

— Nonunion / malunion: more common with subtrochanteric and atypical fractures

— One-year mortality 20–30% — patient and family counseling required

— Dislocation: highest risk first 6–12 weeks; counsel on posterior hip precautions (avoid flexion >90°, adduction past midline, internal rotation) after posterior approach

— Periprosthetic fracture

— Prosthetic joint infection (PJI): early (<3 mo, virulent organisms — S. aureus), delayed (3–24 mo, indolent — coag-neg staph), late hematogenous (>24 mo)

— Aseptic loosening: most common long-term failure

— Leg length discrepancy, nerve injury (sciatic, femoral)

Step 3 management: Any patient with a prosthetic hip presenting with new pain, fever, wound drainage, or persistent pain since surgery must undergo ESR + CRP screening; if elevated, fluoroscopy- or US-guided aspiration for synovial WBC, differential, and culture before starting antibiotics.

Board pearl: Hemoglobin transfusion threshold in stable post-op hip fracture is 7–8 g/dL — liberal transfusion does not improve outcomes (FOCUS trial).

Hip fracture complications (Step 3 favorites):

Total hip arthroplasty complications:

NSAID complications: GI bleed, AKI, hypertension, fluid retention, MI/stroke (especially diclofenac, high-dose ibuprofen)

Intra-articular steroid complications: post-injection flare, infection (rare), accelerated cartilage loss with repeated injections, hyperglycemia, infection risk if THA performed within 3 months

Bisphosphonate-associated complications: atypical femoral fracture (prodromal thigh pain → bilateral femur X-rays), osteonecrosis of the jaw, esophagitis

When to Escalate Care — Consultation and Inpatient Triage

— Suspected septic arthritis (fever, monoarthritis, inability to bear weight, elevated inflammatory markers)

— Hip fracture of any type, including suspected occult fracture in elderly

— Hip dislocation (native or prosthetic) — needs urgent reduction within 6 hours to reduce AVN risk

— Acute neurovascular compromise, suspected cauda equina, or cord compression

— Severe pain uncontrolled in outpatient setting

— Hemodynamic instability from occult retroperitoneal/iliopsoas hemorrhage in anticoagulated patient

— Femoral neck stress fracture (tension-side)

— Advanced AVN with collapse

— Prosthetic joint infection

— Pathologic fracture or impending fracture from metastasis (Mirels score ≥9 → prophylactic fixation)

— Rheumatology: inflammatory arthritis, suspected spondyloarthropathy, crystal arthritis with atypical features

— Infectious disease: septic arthritis, PJI, osteomyelitis

— Oncology / radiation oncology: metastatic bone disease — palliative radiation, bisphosphonates/denosumab, surgical stabilization

— Pain management: refractory pain not amenable to surgery

— PM&R / physical therapy: nearly all chronic hip pain benefits from structured PT

— Geriatrics / orthogeriatric co-management: every elderly hip fracture patient

— Standard floor admission with telemetry if cardiac comorbidity

— ICU for hemodynamic instability, significant blood loss, severe sepsis from septic joint, or high-risk perioperative cardiac/pulmonary disease

CCS pearl: On CCS, consult orthopedics early for any hip fracture or septic hip — delaying consultation while completing imaging or labs costs points. Concurrent ordering (consult + workup + analgesia + NPO + VTE planning) reflects real-world efficient practice.

Key distinction: Native septic arthritis requires urgent surgical washout; prosthetic joint infection requires staged approach (DAIR if acute, two-stage revision if chronic) — both need ID involvement.

Immediate ED transfer / admission:

Urgent orthopedic surgery consult (same day or next day):

Specialty referrals:

Inpatient triage for hip fracture:

Key Differentials — Musculoskeletal Causes of Hip Pain

— Osteoarthritis: insidious groin pain, morning stiffness <30 min, lost internal rotation, joint space narrowing on X-ray

— Inflammatory arthritis: RA (bilateral, small joints involved), spondyloarthropathy (young man, inflammatory back pain, enthesitis, uveitis, IBD/psoriasis association)

— Crystal arthropathy: gout (rare in hip but possible), CPPD (chondrocalcinosis on X-ray)

— Avascular necrosis: groin pain at rest, risk factors (steroids, alcohol, SCD, SLE, HIV); MRI shows double-line sign and crescent sign

— Labral tear / FAI: young active adult, mechanical clicking/catching, positive FADIR; MR arthrography

— Septic arthritis: monoarticular, fever, elevated ESR/CRP, synovial WBC >50,000

— Occult or stress fracture: negative X-ray, positive MRI; high suspicion in elderly fallers and endurance athletes

— Greater trochanteric pain syndrome / gluteal tendinopathy: lateral hip pain, worse lying on side, tender over greater trochanter

— Iliopsoas bursitis/tendinopathy: anterior groin pain, snapping with hip flexion-extension

— Ischiogluteal bursitis: posterior pain with prolonged sitting

— Hamstring origin tendinopathy / proximal tear: pain at ischial tuberosity, weakness with knee flexion

— Adductor strain: groin pain with resisted adduction

— Osteitis pubis: midline pubic symphysis pain in athletes and postpartum patients

— Paget disease: elderly with elevated alk phos, bony enlargement, classic X-ray findings (cortical thickening, "blade of grass" lytic front)

— Transient osteoporosis of the hip: pregnant/postpartum or middle-aged men, marrow edema on MRI, self-limited

Board pearl: Loss of internal rotation in flexion is the earliest and most reliable physical sign of true hip joint pathology — its absence makes intra-articular hip disease unlikely and shifts your differential to peri-articular or referred causes.

Intra-articular (true hip joint):

Peri-articular soft tissue:

Bone:

Key Differentials — Non-Musculoskeletal and Referred Causes

— L1–L2 radiculopathy → groin pain

— L5 radiculopathy → lateral thigh/buttock pain, can mimic trochanteric bursitis

— Lumbar spinal stenosis → neurogenic claudication, improves with forward flexion

— Facet arthropathy, SI joint dysfunction

— Workup: lumbar exam, straight-leg raise, dermatomal sensory testing; MRI lumbar spine if persistent or with red flags

— Inguinal or femoral hernia: bulge with Valsalva, groin pain

— Diverticulitis (left), appendicitis (right): can present with hip pain due to psoas irritation

— Psoas abscess: fever, back/flank/hip pain, positive psoas sign; CT abdomen/pelvis

— Pelvic inflammatory disease, tubo-ovarian abscess, ovarian torsion in women of reproductive age

— Endometriosis: cyclical pelvic and hip pain

— Prostatitis, epididymitis in men

— Nephrolithiasis: flank to groin radiation

— Aortoiliac occlusive disease (Leriche syndrome): buttock/hip/thigh claudication, impotence, diminished femoral pulses

— Iliac artery aneurysm / dissection

— Retroperitoneal hematoma in anticoagulated patient (often after minor fall) — falling hemoglobin, hypotension, hip/back pain

— Metastatic bone disease (breast, prostate, lung, renal, thyroid, multiple myeloma) — night pain, weight loss, lytic/blastic lesions

— Primary bone tumors: chondrosarcoma, osteosarcoma (rare in adults)

— Lymphoma with bony involvement

Key distinction: Vascular claudication (aortoiliac) is reproducible at a fixed walking distance and relieved by rest while standing; neurogenic claudication (spinal stenosis) is relieved by lumbar flexion (leaning on a cart) — not by simply stopping.

Board pearl: Hip pain in an anticoagulated elderly patient after a minor fall with falling hemoglobin is retroperitoneal hemorrhage until proven otherwise — get a non-contrast CT abdomen/pelvis.

Lumbosacral spine (commonly mimics hip):

Intra-abdominal / pelvic:

Vascular:

Neoplastic:

Infectious: osteomyelitis (especially in IVDU, diabetics), TB hip (chronic indolent course in endemic areas or immunocompromised)

Neurologic: meralgia paresthetica (lateral femoral cutaneous nerve entrapment — burning anterolateral thigh, no weakness)

Secondary Prevention and Long-Term Plan

— Osteoporosis pharmacotherapy initiated before or shortly after discharge:

— First-line: alendronate 70 mg weekly or zoledronic acid 5 mg IV yearly (preferred if adherence concerns or GI issues)

— Severe osteoporosis (T-score ≤–3.0, multiple fractures): start with anabolic (teriparatide, romosozumab) then transition to antiresorptive

— Continue for 3–5 years, then reassess ("drug holiday" considerations)

— Calcium 1200 mg/day (preferably dietary) and vitamin D 800–1000 IU/day; check 25-OH vitamin D, target >30 ng/mL

— Fall prevention: medication review, home safety assessment, vision correction, balance/strength PT, vitamin D

— DEXA scheduled within 1–2 years to monitor response

— VTE prophylaxis 10–35 days

— Hip precautions (especially posterior approach) for 6–12 weeks

— Routine antibiotic prophylaxis for dental procedures is not universally recommended — individualized for high-risk patients (immunocompromised, first 2 years post-implant) per AAOS/ADA

— Annual orthopedic follow-up with X-rays to assess implant

— Complete antibiotic course, follow ESR/CRP trends

— ID follow-up; assess source (endocarditis evaluation if bacteremia)

— Long-term exercise program, weight management, low-impact activity (swimming, cycling)

— Avoid chronic opioids; periodic reassessment for arthroplasty candidacy

— Address comorbidities (cardiovascular risk, depression, sleep)

Step 3 management: Every fragility hip fracture should trigger osteoporosis treatment within the index hospitalization — this is a measured quality metric and the single highest-impact secondary prevention intervention. The 30–50% treatment gap post-hip fracture is a known patient safety issue.

After hip fracture (the highest-yield Step 3 longitudinal scenario):

After total hip arthroplasty:

After septic arthritis or PJI:

Chronic hip OA:

Inflammatory arthritis: DMARD optimization with rheumatology, treat-to-target approach

Smoking cessation, alcohol moderation, diabetes control: all improve surgical outcomes and slow OA progression

Follow-Up, Monitoring, and Rehab/Counseling

— Post-hip fracture: PCP visit at 1–2 weeks for medication reconciliation, pain control, wound check, delirium screening; ortho at 2–6 weeks; geriatrics ongoing

— Post-THA: ortho at 2 weeks (wound, suture removal), 6 weeks (begin advancing activity), 3 months, 1 year, then annually

— Hip OA on conservative therapy: reassess at 4–6 weeks, then every 3–6 months; escalate if function deteriorates

— AVN under observation: MRI every 3–6 months initially to assess for collapse

— Post-fracture/post-THA: PT focused on gait training, hip abductor strengthening, balance; progress from walker → cane → unassisted

— Hip OA: PT for hip and core strengthening, ROM, aerobic conditioning; aquatic therapy effective when land-based painful

— Tendinopathy/bursitis: eccentric loading program for gluteal tendinopathy

— NSAIDs: BP, renal function (BUN/Cr), CBC, BP every 3–6 months on chronic therapy

— Bisphosphonates: 25-OH vitamin D, calcium, renal function before dosing; assess adherence; reassess at 3–5 years

— Opioids (if any): PDMP check, urine drug screen, naloxone co-prescription, functional reassessment

— Post-PJI: ESR/CRP trends during and after antibiotic course

— Weight loss in OA: 5–10% reduction yields meaningful symptom relief

— Activity modification: low-impact > high-impact; running not contraindicated in mild OA

— Fall prevention in elderly: scatter rug removal, grab bars, night lighting, hip protectors in high-risk patients

— Return-to-driving after THA: typically 4–6 weeks (right hip), 1–2 weeks (left hip, automatic transmission)

— Sexual activity post-THA: safe at 6 weeks, avoid extreme hip flexion if posterior approach

Board pearl: Hip abductor strengthening is the single most evidence-based exercise across hip OA, GTPS, post-THA rehab, and runner's hip pathology — the gluteus medius is the workhorse of the lateral chain.

Key distinction: Recovery milestones after THA are measured in weeks, not months — patients walking with a cane at 2 weeks and unassisted by 6 weeks reflect normal trajectory.

Outpatient follow-up cadence:

Rehabilitation:

Monitoring parameters:

Counseling priorities:

Ethical, Legal, and Patient Safety Considerations

— Discuss alternatives, including nonoperative management with realistic mortality and functional decline for elderly fracture patients

— In patients with dementia or cognitive impairment, assess decision-making capacity for the specific decision; engage surrogate decision-maker per state hierarchy

— Document goals-of-care conversation; some frail elderly patients with limited life expectancy and advanced dementia may reasonably decline surgery — palliative comfort care is a legitimate option

— Medication reconciliation at every transition (ED → floor → SNF → home) — anticoagulants, analgesics, osteoporosis meds, home medications

— Communicate VTE prophylaxis duration explicitly to receiving facility

— Schedule PCP follow-up within 1–2 weeks before discharge; arrange home health/PT

— Provide written hip precautions and red-flag symptoms

— Fall prevention bundle: bed alarms, low beds, hourly rounding, toileting schedule

— Delirium prevention: reorientation, sleep, hydration, pain control, minimize tethers and deliriogenic meds

— Pressure injury prevention: turning schedule, heel offloading, support surfaces

— CAUTI prevention: remove Foley by POD #2 unless specific indication

— Elder abuse: suspected abuse or neglect in an elderly patient with unexplained fractures or inconsistent histories triggers Adult Protective Services reporting (mandatory in most US states)

— Document objectively; report on reasonable suspicion, not proof

Step 3 management: When an elderly patient with hip fracture and advanced dementia is brought in by family who disagree about surgery, your obligation is to (1) assess capacity, (2) identify the legal surrogate, (3) facilitate a goals-of-care discussion grounded in prognosis and prior expressed wishes, and (4) document — not to default to maximal intervention.

Informed consent for THA / hip fracture surgery:

Capacity assessment: the threshold is decision-specific; a patient may lack capacity for complex financial decisions but retain capacity to consent to a surgery they understand

Transitions of care (high-risk window for elderly hip patients):

Patient safety in the hospital:

Mandatory reporting:

Driving safety: counsel and document return-to-driving guidance post-surgery and post-opioid initiation

Health equity: osteoporosis treatment gaps are larger in men and minorities after fragility fracture — proactively address

High-Yield Associations and Rapid-Fire Clinical Facts

Board pearl: The hip is too deep for blind aspiration — always use ultrasound or fluoroscopic guidance. This single fact distinguishes the hip from knee/shoulder management on Step 3 vignettes.

Loss of internal rotation = earliest sign of hip OA

Groin pain = intra-articular; lateral pain = trochanteric/bursa; buttock pain = spine/SI/sciatic

Knee pain referred from hip via obturator nerve — always examine the hip in a patient with isolated knee pain

Cane in contralateral hand — reduces hip joint force by ~40%

AVN risk factors: A SICk PLACE — Alcohol, Steroids, Idiopathic, Caisson disease, Pancreatitis, Lupus/SLE, AVN-prone fractures, Chronic renal disease, Sickle cell/SCD, Embolism (fat)... include HIV antiretrovirals, transplant

Double-line sign on T2 MRI = AVN

Crescent sign on X-ray = subchondral fracture in late AVN, pre-collapse

Synovial WBC >50,000 with >75% PMNs = septic arthritis

Tension-side femoral neck stress fracture = surgical emergency (superior cortex, displacement risk)

Compression-side stress fracture = conservative management (inferior cortex)

Bisphosphonate >5 years + prodromal thigh pain = atypical femoral fracture, image bilateral femurs

Hip fracture 1-year mortality = 20–30%

Surgery within 24–48 hours reduces hip fracture mortality

Posterior THA approach → posterior dislocation precautions (no flexion >90°, no adduction past midline, no IR)

THA dislocation in first 6–12 weeks is highest risk

Hyaluronic acid injection = not recommended for hip OA

Acetaminophen max 2 g/day in chronic liver disease

NSAIDs avoid if eGFR <30, decompensated CHF, recent CABG, active GI bleed

PJI workup: ESR + CRP → if elevated, image-guided aspiration → synovial WBC, %PMN, culture, alpha-defensin

VTE prophylaxis post-hip surgery: 10–35 days

FAI testing: FADIR maneuver

Trendelenburg gait = hip abductor weakness

Meralgia paresthetica = lateral femoral cutaneous nerve entrapment (obesity, tight belts, pregnancy)

Leriche syndrome = aortoiliac occlusive disease (buttock claudication, impotence, absent femoral pulses)

Transient osteoporosis of the hip = self-limited, pregnant/postpartum or middle-aged men

Board Question Stem Patterns

Step 3 management: Recognize the trigger in each stem (red flag → urgent imaging or referral; risk factor cluster → specific diagnosis; functional decline → escalate management) and match to the next best step, not the definitive diagnosis.

Stem 1 — The classic OA presentation: 62-year-old obese woman with insidious right groin pain worse with activity, morning stiffness 15 minutes, loss of internal rotation. Answer: weight loss, exercise/PT, NSAIDs; refer for THA when conservative fails.

Stem 2 — Elderly fall, negative X-ray: 78-year-old woman with hip pain after a fall, unable to bear weight, X-rays read as negative. Answer: MRI hip within 24–48 hours — occult femoral neck fracture.

Stem 3 — Septic hip: febrile patient with monoarticular hip pain, ESR/CRP elevated. Answer: image-guided aspiration before antibiotics, then empiric vancomycin + ceftriaxone, urgent ortho consult for washout.

Stem 4 — Steroid user with rest pain: 35-year-old SLE patient on chronic prednisone with bilateral groin pain. Answer: MRI hips for AVN; double-line sign confirms.

Stem 5 — Endurance runner with groin pain: female runner with amenorrhea (RED-S), groin pain worse with activity. Answer: MRI for femoral neck stress fracture; if tension-side, surgical fixation; address energy availability, calcium/vitamin D, menstrual function.

Stem 6 — Post-hip-fracture discharge: 80-year-old after intertrochanteric fracture repair, no osteoporosis treatment. Answer: start bisphosphonate or zoledronic acid before discharge, calcium + vitamin D, DEXA, fall prevention referral.

Stem 7 — Anticoagulated faller: 75-year-old on warfarin after minor fall, hip and back pain, falling hemoglobin. Answer: non-contrast CT abdomen/pelvis — retroperitoneal hematoma; reverse anticoagulation.

Stem 8 — Lateral hip pain lying on side: 55-year-old with lateral hip pain worse at night when lying on affected side. Answer: greater trochanteric pain syndrome → PT for abductors, NSAIDs, image-guided steroid if refractory.

Stem 9 — Buttock claudication, impotence: older male smoker. Answer: Leriche syndrome — ABI, vascular surgery consult.

Stem 10 — Bisphosphonate use 7 years, prodromal thigh ache: Answer: bilateral femur X-rays for atypical fracture.

Stem 11 — New pain after THA, no fever: ESR/CRP elevated. Answer: image-guided joint aspiration for synovial cell count and culture — PJI workup.

One-Line Recap

Adult hip pain is triaged by localization (groin = intra-articular, lateral = bursa/tendon, buttock = spine/SI/vascular), red flags (fever, inability to bear weight, rest/night pain, steroid use, anticoagulation), and functional impact — with weight-bearing AP pelvis + lateral as the universal first imaging step and MRI reserved for occult fracture, AVN, labral pathology, or prosthetic joint infection workup.

— Loss of internal rotation in flexion is the most reliable physical sign of true hip joint pathology; groin pain is its most common location, and referred knee pain is a classic trap

— Elderly faller + inability to bear weight + negative X-ray = MRI within 24–48 hours to exclude occult femoral neck fracture; if confirmed, surgery within 24–48 hours reduces mortality, and discharge must include osteoporosis pharmacotherapy + calcium/vitamin D + fall prevention

— Septic hip workup requires image-guided aspiration before antibiotics (the hip is too deep for blind tap); synovial WBC >50,000 with >75% PMNs confirms; treat with empiric vancomycin + ceftriaxone and urgent surgical washout

— AVN is suggested by groin pain at rest in a patient with steroids, alcohol, SCD, SLE, or HIV exposure — MRI shows the double-line sign; pre-collapse disease may benefit from core decompression, post-collapse needs THA

— Hip OA conservative ladder: education + weight loss + exercise/PT → topical/oral NSAIDs → image-guided steroid → total hip arthroplasty; avoid hyaluronic acid and chronic opioids

— Bisphosphonate use >5 years + prodromal thigh pain → bilateral femur X-rays for atypical femoral fracture

— Transitions of care matter: every fragility hip fracture deserves medication reconciliation, PCP follow-up at 1–2 weeks, osteoporosis treatment initiated in-hospital, and structured fall prevention — the post-hip-fracture treatment gap is a documented patient safety failure

Board pearl: When in doubt on Step 3, localize → red flag check → AP pelvis + lateral → targeted advanced imaging → match management to the specific diagnosis, not to symptoms alone.

High-yield recap bullets: