Step 2 CK · Orthopedics & Sports Medicine

Nontraumatic Hip & Knee Pain

Name: Nontraumatic Hip & Knee Pain
Creator: Veli Bakalov, MD

Point to the pain: location sorts hip and knee overuse syndromes

Orthopedics & Sports Medicine·Lower Extremity·6 min read·9 high-yield points·Reviewed by Veli Bakalov, MD @HemeOncBuddy

Study materialsNo account needed

Card deckActive-recall cards · quick checks · quiz

High-yield

Groin pain means the hip joint (OA, osteonecrosis, FAI); lateral trochanteric pain is GTPS; burning anterolateral thigh is meralgia paresthetica; buttock pain radiating down the leg is spinal.
Hip osteoarthritis loses internal rotation first; X-ray shows joint-space narrowing, osteophytes, sclerosis, and cysts.
Osteonecrosis of the femoral head (glucocorticoids, alcohol, sickle cell, SLE) has a normal early X-ray → MRI of both hips.
Pre-collapse osteonecrosis → protected weight bearing and core decompression; collapse or secondary OA → total hip arthroplasty.
Young athlete with groin pain, clicking, and positive FADIR → femoroacetabular impingement with labral tear; MR arthrography shows the tear.
Meralgia paresthetica is sensory-only lateral femoral cutaneous nerve compression (belts, obesity, pregnancy); weakness or reflex loss points elsewhere.
Patellofemoral pain (stairs, squatting, prolonged sitting) is treated with quadriceps and hip strengthening, not imaging.
IT band syndrome = lateral epicondyle pain in runners; jumper's knee = inferior patellar pole; pes anserine = medial tibia below the joint line.
Hot prepatellar bursa → aspirate to exclude septic bursitis (S. aureus); ruptured Baker cyst mimics DVT → duplex ultrasound first.

Approach: let location guide the diagnosis

Hip and thigh. Ask the patient to point. Groin or deep anterior hip pain comes from the hip joint itself (osteoarthritis, osteonecrosis, femoroacetabular impingement with labral tear). Lateral hip pain with tenderness over the greater trochanter is greater trochanteric pain syndrome. Burning or numbness over the anterolateral thigh with normal strength is meralgia paresthetica, and buttock pain radiating down the leg usually arises from the lumbar spine or sacroiliac joint.

Hip joint pain often refers to the knee (obturator nerve): examine the hip in anyone with knee pain and a normal knee exam.

Knee. Pain around or behind the patella suggests patellofemoral pain; the inferior patellar pole, patellar tendinopathy; the lateral femoral epicondyle in a runner, iliotibial band syndrome; and the anteromedial tibia below the joint line, pes anserine bursitis. Swelling in front of the patella is prepatellar bursitis and posterior fullness a Baker cyst. Joint-line pain with effusion, locking, or instability suggests internal derangement (meniscus or ligament) instead.

Hip joint disorders

Osteoarthritis. An older adult has gradually worsening groin pain on weight bearing, brief morning stiffness, and a limp. Painful, restricted internal rotation is the earliest exam finding; contractures and shortening come late. Radiographs show joint-space narrowing, osteophytes, subchondral sclerosis, and cysts. Treatment is weight loss, exercise and physical therapy, NSAIDs, and image-guided corticosteroid injection, with total hip arthroplasty for refractory pain and disability.

Osteonecrosis. Interrupted blood supply, mainly from the medial femoral circumflex artery, kills subchondral bone of the femoral head. Leading nontraumatic causes are glucocorticoids and alcohol, followed by sickle cell disease, SLE, and decompression (caisson) disease; femoral neck fracture and hip dislocation are traumatic causes (mnemonic ASEPTIC: Alcohol, Sickle cell and Steroids, Erythematosus, Pancreatitis, Trauma, Idiopathic, Caisson). Insidious groin pain worsens with weight bearing, and disease is often bilateral.

Imaging and treatment. Early osteonecrosis is invisible on plain films, so a normal X-ray with high suspicion calls for MRI, the most sensitive test (double-line sign); image both hips. Later radiographs show sclerosis, a subchondral crescent sign (subchondral fracture), and then collapse of the femoral head. Before collapse (no crescent sign or subchondral fracture), options are protected weight bearing and core decompression; once the head has collapsed or secondary arthritis develops, total hip arthroplasty is definitive.

Femoroacetabular impingement. A nonspherical femoral head–neck junction (cam) or acetabular overcoverage (pincer) abuts during flexion and internal rotation, tearing the labrum and predisposing to early osteoarthritis. Young athletes (hockey, soccer, dance) describe deep groin pain with clicking or catching, and the FADIR test (flexion, adduction, internal rotation) reproduces it. Radiographs show the bony morphology and MR arthrography the labral tear. Physical therapy and activity modification come first, with arthroscopy for refractory symptoms.

Groin pain from the hip joint

Feature	Osteoarthritis	Osteonecrosis	FAI / labral tear
Typical patient	Older adult	Steroids, alcohol, sickle cell, SLE	Young athlete
Key exam	Lost internal rotation	Painful, limited motion	Positive FADIR, clicking
Best imaging	X-ray	MRI (X-ray normal early)	X-ray, then MR arthrography
Treatment	Exercise, NSAIDs, injection, arthroplasty	Core decompression before collapse; arthroplasty after	PT; arthroscopy if refractory

Lateral hip and thigh

Greater trochanteric pain syndrome. Formerly called trochanteric bursitis, this is mostly gluteus medius and minimus tendinopathy with or without bursitis. It affects middle-aged women, people with obesity, and runners, causing lateral hip pain with point tenderness over the trochanter, worse when lying on that side, climbing stairs, or rising from a chair. Treat with physical therapy (hip abductor strengthening and stretching), NSAIDs, weight loss, and a corticosteroid injection if symptoms persist.

Meralgia paresthetica. The lateral femoral cutaneous nerve (L2–L3) is purely sensory and is compressed where it passes under the inguinal ligament near the anterior superior iliac spine. Obesity, tight belts or tool belts, pregnancy, and diabetes predispose. Patients describe burning, tingling, and numbness over the anterolateral thigh, while strength and the patellar reflex are normal. Management is removing the compression (looser clothing, weight loss), NSAIDs, and reassurance; pregnancy-related cases usually resolve after delivery, and a nerve block is both diagnostic and therapeutic for persistent symptoms.

Quadriceps weakness or a reduced patellar reflex excludes meralgia paresthetica: evaluate for femoral neuropathy or an L3–L4 radiculopathy.

Knee overuse syndromes

Patellofemoral pain syndrome. The most common cause of knee pain in adolescents and young adults, especially female runners. Diffuse pain around or behind the patella worsens with stairs (particularly descending), squatting, kneeling, and prolonged sitting (theater sign), with no effusion or instability. Diagnosis is clinical without imaging. Treatment is quadriceps and hip abductor and external rotator strengthening, activity modification, and short-term NSAIDs; surgery has no role.

Iliotibial band syndrome. The band rubs or compresses over the lateral femoral epicondyle during repetitive knee flexion in runners and cyclists. Lateral knee pain starts predictably partway into a run and worsens downhill; the epicondyle is tender and the Ober test shows a tight band. Treat with reduced mileage, stretching, hip abductor strengthening, NSAIDs, and a corticosteroid injection if refractory.

Patellar tendinopathy. Jumper's knee is overload degeneration of the proximal patellar tendon in basketball and volleyball players, with tenderness at the inferior patellar pole and pain on jumping, landing, and squatting. Load management and eccentric strengthening (decline squats) are the core treatment; avoid corticosteroid injection into the tendon because of rupture risk. In a growing adolescent, tibial tubercle pain is Osgood-Schlatter apophysitis instead.

Pes anserine bursitis. Pain and tenderness over the anteromedial proximal tibia a few centimeters below the medial joint line, where the sartorius, gracilis, and semitendinosus insert (Say Grace before Tea). It is common in overweight women with knee osteoarthritis and in runners. Tenderness below, rather than at, the joint line separates it from meniscal and arthritic pain. Treat with rest, ice, NSAIDs, hamstring stretching, physical therapy, or injection.

Bursae and cysts around the knee

Prepatellar bursitis. Housemaid's knee follows repeated kneeling in carpet layers, roofers, plumbers, and gardeners. Fluctuant swelling sits in front of the patella, and knee motion is largely preserved, unlike a joint effusion. Infrapatellar bursitis (clergyman's knee) is the analogous swelling below the patella.

Look for infectionWarmth, erythema, fever, cellulitis, or a skin break over the bursa.
Aspirate the bursaGram stain, culture, cell count, and crystals; the joint is not tapped when motion is preserved.
TreatSeptic (usually S. aureus): antibiotics with repeat drainage. Aseptic: knee pads, compression, activity change, NSAIDs.

Baker cyst. A popliteal cyst is a distended gastrocnemius–semimembranosus bursa fed by joint fluid from osteoarthritis, rheumatoid arthritis, or a meniscal tear. Rupture releases fluid into the calf, producing sudden calf pain, swelling, erythema, and sometimes bruising that tracks to the ankle. Because it mimics deep vein thrombosis, and a large cyst can compress the popliteal vein and cause true DVT, duplex ultrasound comes first. Treatment is rest, elevation, NSAIDs, and control of the underlying arthritis, sometimes with aspiration and intra-articular corticosteroid to reduce the effusion.