High Yield Overview

Imaging the Pelvis and Hip — Systematic Approach

From AP Pelvis to MRI Hip Assessment

AP PelvisStandard first-line investigation

ShentonLine disruption = NOF fracture/dislocation

MRIGold standard for occult NOF fracture

24hrMRI within 24 hours for suspected occult NOF

AVNMRI detects before radiographic changes

FAIAlpha angle more than 55 degrees = cam morphology

JudetViews for acetabular fracture assessment

DDHUSS before 6 months, radiograph after

Hip and Pelvis Imaging Modality Selection

Radiography: First-line for ALL presentations. AP pelvis + lateral hip

MRI: Occult NOF fracture (within 24hr), AVN staging, labral assessment, bone marrow oedema

CT: Acetabular fracture classification (Letournel-Judet), 3D planning

Ultrasound: Paediatric DDH screening, hip effusion, guided injection

MR Arthrography: Labral tear assessment, FAI pre-surgical planning

Key: AP pelvis first, then selected advanced imaging based on clinical question

Critical Must-Knows

AP pelvis radiograph is the standard first-line investigation for all hip and pelvic presentations.
Shenton line: a smooth arc along the inferior border of the superior pubic ramus and medial femoral neck — disruption indicates fracture or dislocation.
MRI within 24 hours is the gold standard for occult NOF fracture when radiographs are normal and clinical suspicion persists.
AVN staging uses Ficat-Arlet or Steinberg classification — MRI detects AVN at Stage I (preclinical), before radiographic changes.
Femoroacetabular impingement: alpha angle (cam) and lateral centre-edge angle (pincer) are key measured parameters.

Examiner's Pearls

"
In elderly patients with hip pain after a fall, if the AP pelvis is normal, 2-5% have an occult NOF fracture — MRI MUST be performed within 24 hours.
"
The Garden classification for NOF fractures: I (incomplete/valgus impacted), II (complete non-displaced), III (complete partially displaced), IV (complete fully displaced). III-IV have highest AVN risk.
"
Acetabular fractures: Judet views (45 degree obliques) assess the anterior and posterior columns and walls. CT with 3D reconstruction is essential for Letournel-Judet classification.
"
Paediatric hip imaging: USS is the primary modality before 6 months (Barlow/Ortolani), AP pelvis radiograph after 6 months (Perkins and Hilgenreiner lines for DDH).
"
Perthes disease: MRI shows extent of epiphyseal involvement (Catterall, Herring lateral pillar classification) better than radiographs.

Exam Warning

Pelvis and hip imaging is tested extensively in both written and viva formats. You must know: systematic AP pelvis reading, Shenton line, Garden classification for NOF fractures, the occult NOF fracture pathway (MRI within 24 hours), AVN staging on MRI, acetabular fracture assessment (Judet views, Letournel-Judet classification), paediatric hip imaging (DDH lines, Perthes staging), and FAI imaging (alpha angle, LCEA). Classic traps: discharging an elderly patient with hip pain and normal radiographs without arranging urgent MRI.

Mnemonic

SHIPSystematic AP Pelvis Assessment

Shenton line and sacroiliac joints

Shenton line: smooth arc along inferior pubic ramus and medial femoral neck. SI joints: symmetry, widening, sclerosis (sacroiliitis)

Hip joint (GH joint congruence, JSW)

Hip joint space width (normal more than 4mm medially), joint congruence, femoral head sphericity, osteophytes, subchondral changes

Iliac wings, ischium, and pubic rami

Trace all pelvic ring cortices. The pelvic ring MUST be broken in two places — if you find one fracture, ALWAYS look for a second

Proximal femur (NOF, trochanters)

Femoral neck: cortical integrity, trabecular pattern (Singh index), fracture lines. Greater and lesser trochanter avulsions

Memory Hook:SHIP: Sail through the AP pelvis systematically — Shenton, Hip joint, Iliac wings, Proximal femur.

Mnemonic

PAINOccult NOF Fracture Pathway

Plain radiograph normal

Initial AP pelvis and lateral hip show no definitive fracture, but the patient has hip pain and inability to weight-bear after a fall

Act within 24 hours (MRI)

MRI MUST be performed within 24 hours — it has 99-100% sensitivity for occult NOF fracture and is the gold standard investigation

If MRI unavailable: CT is second-line

CT has lower sensitivity (approximately 80%) for undisplaced fractures but is acceptable when MRI is not available within 24 hours

No missed fractures (medicolegal risk)

Delayed diagnosis of occult NOF fracture is a common cause of medicolegal claims. Every elderly patient with hip pain after a fall and normal X-ray needs urgent MRI

Memory Hook:PAIN: an elderly patient in PAIN after a fall with normal X-rays STILL NEEDS MRI — do NOT discharge without it.

Mnemonic

Garden I-IVGarden Classification for NOF Fractures

Incomplete (valgus impacted)

Trabeculae visible, impacted in valgus. The LEAST displaced. Low AVN risk. Often missed on radiographs

Complete non-displaced (Type II)

Complete fracture line but fragments remain in anatomical position. Moderate AVN risk

Complete partially displaced (Type III)

Femoral head rotates. Retinacular vessels partially disrupted. HIGH AVN risk

Complete fully displaced (Type IV)

Femoral head fully displaced from neck. Complete retinacular vessel disruption. HIGHEST AVN risk (approaching 100% without treatment)

Memory Hook:Garden Types: I=impacted (lowest risk), II=non-displaced, III=partially displaced, IV=fully displaced (highest AVN risk). Non-displaced (I-II): fix. Displaced (III-IV): replace (in elderly).

Overview

Systematic pelvis and hip imaging encompasses a broad spectrum of pathology from acute trauma (NOF fracture, acetabular fracture, pelvic ring disruption) to chronic conditions (OA, AVN, FAI, DDH). The AP pelvis radiograph is the essential first-line investigation, with advanced imaging selected based on the clinical question.

The most important clinical scenario is the elderly patient with hip pain after a fall and normal radiographs — this requires urgent MRI to exclude an occult NOF fracture. Delayed diagnosis is one of the most common causes of medicolegal claims in orthopaedic practice.

Key Radiographic Assessment Points

On the AP pelvis: (1) Check adequacy — both hips visible, symmetric obturator foramina (no rotation), coccyx aligned with symphysis. (2) Shenton line bilaterally — disruption indicates fracture or dislocation. (3) Hip joint spaces — bilateral comparison, normal more than 4mm (medial JSW). (4) Pelvic ring integrity — trace the entire ring, looking for disruption at pubic rami, SI joints, and acetabulum. Remember: the pelvic ring must break in TWO places. (5) Femoral neck — cortical integrity, trabecular pattern. Garden I fractures may show only a valgus impaction line. (6) Lesser trochanter profile — if visible in straight AP, suggests external rotation from displaced NOF fracture.

When MRI Changes Management

MRI is critical in: (1) Occult NOF fracture (radiographs normal, clinical suspicion) — MRI within 24 hours has 99-100% sensitivity. (2) AVN staging — MRI detects stage I (pre-radiographic) AVN with the 'double line sign' (band pattern of low signal on T1 with high signal on T2). (3) Labral tears — MR arthrography (sensitivity 87%) for FAI workup. (4) Transient osteoporosis — diffuse bone marrow oedema without AVN changes. (5) Bone marrow pathology — metastases, myeloma infiltration, stress fractures. (6) Perthes disease staging — extent of epiphyseal involvement.

Clinical Imaging

Imaging Gallery

Hip radiograph and MRI correlation demonstrating complementary imaging assessment — Two-panel comparison of hip radiograph and MRI demonstrating how advanced imaging reveals pathology invisible on plain radiographs. MRI is essential for occult fracture detection, AVN staging, and labral assessment — all conditions where radiographs may appear normal despite significant pathology.Credit: Open-i (NIH) (Open Access (CC BY))

Bilateral hip AVN demonstrating MRI staging with multiplanar images — Multiplanar MRI of bilateral hip AVN demonstrating the characteristic signal changes used for staging. MRI is the most sensitive and specific modality for AVN detection, showing changes at Ficat-Arlet Stage I (pre-radiographic) including the pathognomonic 'double line sign' on T2-weighted images.Credit: Open-i (NIH) (Open Access (CC BY))

Systematic Approach

Systematic Pelvis and Hip Imaging Assessment

Pelvis/Hip Imaging Selection Guide

Clinical Scenario	First-Line Imaging	Advanced Imaging
Elderly hip pain after fall	AP pelvis + lateral hip radiograph	MRI within 24 hours if normal radiographs and clinical suspicion persists (occult NOF fracture). CT if MRI unavailable
Suspected acetabular fracture	AP pelvis + Judet views (45 degree obliques)	CT with 3D reconstruction for Letournel-Judet classification and surgical planning. MRI for associated labral/cartilage injury
Pelvic ring injury	AP pelvis + inlet/outlet views	CT for complete ring assessment (posterior ring is often underestimated on radiographs). Angiography if haemodynamically unstable
Suspected AVN	AP pelvis + frog lateral hip	MRI: gold standard for early AVN detection (pre-radiographic). Ficat-Arlet or Steinberg classification
Young adult hip pain (FAI)	AP pelvis + Dunn view (45 degree flexion lateral)	MR arthrography for labral assessment. CT for alpha angle measurement, head-neck offset ratio
Paediatric DDH	USS (less than 6 months) or AP pelvis (more than 6 months)	MRI if USS equivocal. Arthrography (fluoroscopic) for concentric reduction assessment during surgery

Clinical Applications

Neck of Femur Fracture Imaging

Radiographic detection: The AP pelvis radiograph detects approximately 95-98% of NOF fractures. Key signs: (1) cortical discontinuity at the femoral neck, (2) disruption of Shenton line, (3) trabecular pattern disruption (medial calcar compression), (4) valgus angulation (Garden I — impacted), (5) shortening and external rotation of the affected limb (displaced fracture — lesser trochanter becomes prominent).

Garden classification on radiographs: Garden I (incomplete/impacted): subtle valgus impaction line, trabeculae still visible. Often the most difficult to detect. Garden II (complete non-displaced): fracture line visible across the entire neck, fragments in anatomical position. Garden III (partially displaced): femoral head rotated but still in contact with the neck. Garden IV (fully displaced): complete separation, femoral head may be in acetabulum while neck/shaft retract.

Occult NOF fracture: In 2-5% of patients, the initial radiograph is NORMAL despite a genuine fracture. These patients present with hip pain, inability to weight-bear, and pain on internal rotation. Clinical suspicion MUST lead to MRI within 24 hours. MRI has 99-100% sensitivity for occult NOF fracture. On MRI: a fracture line appears as a low-signal line on T1 surrounded by bone marrow oedema (high signal on T2/STIR). The fracture configuration (subcapital, transcervical, basicervical) and displacement determine management.

CT as alternative: When MRI is unavailable, CT has approximately 80% sensitivity for undisplaced NOF fractures. CT is inferior to MRI for this indication but is a reasonable alternative in emergency settings.

Evidence Base

MRI for Occult NOF Fracture

Systematic Review

Carpenter CR, Schuur JD, Everett WW, Pines JM • Academic Emergency Medicine (2010)

Key Findings:

MRI had sensitivity of 99-100% and specificity of 100% for occult hip fracture.
CT sensitivity was approximately 80% for undisplaced fractures (inferior to MRI).
Delayed MRI (more than 24 hours) did not reduce sensitivity but delayed treatment, increasing morbidity.

Clinical Implication: MRI within 24 hours is the gold standard for suspected occult NOF fracture — failure to arrange MRI is a common medicolegal pitfall.

Limitation: MRI availability may limit timely imaging, particularly in rural settings. CT is an acceptable alternative.

Source: Carpenter CR et al. Acad Emerg Med 2010;17(5):488-98

Garden Classification and AVN Risk

Cohort Study

Garden RS • Journal of Bone and Joint Surgery (British) (1961)

Key Findings:

Garden I-II (non-displaced): AVN rate 8-15%. Internal fixation is the treatment of choice.
Garden III-IV (displaced): AVN rate 30-65%. In elderly patients, arthroplasty is preferred.
The trabecular pattern alignment on the AP view was the basis for the classification system.

Clinical Implication: The Garden classification determines management: non-displaced (I-II) fractures are fixed; displaced (III-IV) fractures in the elderly are replaced.

Limitation: Inter-observer reliability is moderate — many surgeons simplify to 'displaced' vs 'non-displaced'.

Source: Garden RS. JBJS Br 1961;43-B:647-63

NOF fracture imaging has direct management implications.

Australian Context

In Australia, hip and pelvis imaging follows evidence-based guidelines. AP pelvis radiograph is universally available as the first-line investigation. MRI for occult NOF fracture is recognised as standard of care by Australian orthopaedic and emergency medicine guidelines, with most major Australian hospitals providing urgent MRI access within 24 hours for this indication.

AVN imaging follows international standards, with MRI being the investigation of choice for early detection. Australian rheumatology and orthopaedic guidelines recognise the importance of early AVN detection for disease-modifying interventions (core decompression). MR arthrography for hip labral assessment is performed in specialist radiology centres across Australian capital cities.

Paediatric DDH screening in Australia follows NHMRC guidelines, with clinical screening at birth and 6-8 week checks. Selective ultrasound screening is performed for at-risk infants (breech presentation, family history, clinical instability). AP pelvis radiograph is the standard imaging modality after 6 months of age when the femoral head ossification centre has appeared.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"An 82-year-old woman presents to the emergency department with hip pain after a fall. She cannot weight-bear. The AP pelvis radiograph appears normal."

EXCEPTIONAL ANSWER

This is one of the most important clinical scenarios in orthopaedic practice and a very common exam question. Despite the normal radiograph, this patient has a HIGH probability of an occult NOF fracture — approximately 2-5% of NOF fractures are not visible on initial radiographs. Given the clinical presentation (elderly, fall, inability to weight-bear, hip pain), I would NOT discharge this patient. My management plan: (1) Immobilisation and analgesia — the patient should be kept comfortable and the hip should not be stressed. (2) MRI of the pelvis and affected hip within 24 hours — this is the gold standard investigation for occult NOF fracture, with sensitivity approaching 99-100%. The MRI sequences include T1 (shows fracture as a dark line disrupting the normal bright fatty marrow), T2/STIR (shows surrounding bone marrow oedema as high signal), and coronal images are most important for NOF assessment. (3) If MRI is unavailable within 24 hours (e.g., rural hospital without MRI), CT is the second-line investigation with approximately 80% sensitivity. If CT is also negative but clinical suspicion remains high, the patient should be transferred for MRI. (4) If MRI confirms a fracture: the fracture configuration (subcapital vs transcervical vs basicervical) and displacement (Garden classification) determine management. In an 82-year-old: non-displaced (Garden I-II) — internal fixation with cannulated screws. Displaced (Garden III-IV) — hemiarthroplasty or total hip arthroplasty. (5) If MRI is NORMAL (no fracture): consider other diagnoses — pubic ramus fracture, acetabular fracture, greater trochanter fracture, pelvic insufficiency fracture, soft tissue injury. These may also be visible on MRI. (6) Regardless of fracture finding, this patient has sustained a fragility fall and requires falls risk assessment and osteoporosis investigation.

KEY POINTS TO SCORE

2-5% of NOF fractures are not visible on initial radiographs (occult fractures)

MRI within 24 hours: gold standard (sensitivity 99-100%) — MUST be arranged

CT is second-line (sensitivity approximately 80%) when MRI unavailable

Garden classification determines management: I-II fix, III-IV replace (in elderly)

Failure to arrange MRI for suspected occult NOF fracture is a medicolegal risk

COMMON TRAPS

✗Discharging the patient based on a normal radiograph alone (medicolegal risk)

✗Not arranging MRI within 24 hours when clinical suspicion persists

✗Not knowing the sensitivity difference between MRI and CT for occult fractures

✗Not considering alternative diagnoses if MRI is negative

VIVA SCENARIOStandard

EXAMINER

"A 35-year-old man on long-term corticosteroids presents with bilateral hip pain. His AP pelvis radiograph shows sclerosis in the right femoral head. MRI of both hips is requested."

EXCEPTIONAL ANSWER

The most likely diagnosis is bilateral avascular necrosis (AVN) of the femoral heads, with the right hip at a more advanced stage than the left. Corticosteroid use is one of the most common causes of non-traumatic AVN. Risk factors for corticosteroid-induced AVN include cumulative dose (more than 2g prednisone equivalent), high-dose pulse therapy, and prolonged use. AVN tends to be bilateral in 50-80% of non-traumatic cases. Expected MRI findings: Right hip (more advanced — already showing radiographic sclerosis): The MRI would likely show Stage II or III Ficat-Arlet disease. On T1-weighted images: a band of low signal (the necrotic zone interface) in the anterosuperior femoral head, with preservation of normal fatty marrow signal above and below. On T2-weighted images: the pathognomonic 'double line sign' — an outer ring of low signal (sclerotic bone) with an inner ring of high signal (granulation tissue at the interface between necrotic and viable bone). If Stage III: a crescent sign (subchondral fracture) may be visible as a thin line of high T2 signal beneath the subchondral plate. This indicates femoral head collapse is imminent or has begun. Left hip (earlier stage — radiographically occult): The MRI may show Stage I AVN — diffuse marrow oedema on STIR/T2 without the characteristic band pattern. Alternatively, it may show early Stage II with a developing band of abnormal signal but without the full double line sign. This is precisely why MRI is essential — it detects contralateral pre-radiographic disease. Management implications based on staging: Stage I-II (pre-collapse, head spherical): core decompression may be considered to relieve intraosseous pressure and potentially slow disease progression. Stage III (subchondral collapse): joint-preserving options are limited. In a young patient, core decompression with bone graft or vascularised fibular graft may be attempted. Stage IV (secondary OA): total hip arthroplasty is the definitive treatment.

KEY POINTS TO SCORE

Corticosteroids: one of the most common causes of non-traumatic AVN

AVN is bilateral in 50-80% of non-traumatic cases — always image BOTH hips

Double line sign on T2: pathognomonic for AVN (sclerotic rim + granulation tissue interface)

MRI detects Stage I (pre-radiographic) AVN 6-12 months before radiographic changes

Ficat-Arlet staging guides management: I-II = core decompression, IV = arthroplasty

COMMON TRAPS

✗Not imaging the contralateral hip (bilateral AVN in 50-80%)

✗Not knowing the double line sign and its significance

✗Not knowing the Ficat-Arlet staging system

✗Confusing AVN with transient osteoporosis (which is self-limiting)

VIVA SCENARIOChallenging

EXAMINER

"An examiner shows you an AP pelvis radiograph and asks you to describe your systematic assessment."

EXCEPTIONAL ANSWER

I would begin by assessing the technical adequacy of the radiograph, then proceed with my systematic SHIP assessment. Technical adequacy: (1) Is the pelvis centred? The coccyx should be aligned with the pubic symphysis (if rotated, the obturator foramina will be asymmetric). (2) Are both hips completely included? (3) Is the exposure adequate to visualise trabecular detail? SHIP assessment: S — Shenton line and sacroiliac joints: I trace Shenton line bilaterally. This smooth arc follows the inferior border of the superior pubic ramus and continues along the medial femoral neck. Any disruption of this arc indicates: NOF fracture (the most common cause in elderly), hip dislocation, or proximal femoral pathology. I then assess both SI joints for symmetry — widening suggests sacroiliac disruption (posterior pelvic ring injury), sclerosis suggests sacroiliitis (ankylosing spondylitis), narrowing/fusion suggests established ankylosis. H — Hip joints: I assess the hip joint spaces bilaterally. Normal medial joint space width is more than 4mm. I look for: joint space narrowing (OA — typically superolateral), osteophytes, subchondral sclerosis and cysts, femoral head sphericity (loss of sphericity = AVN collapse, DDH subluxation). I compare both sides. Protrusio acetabuli: the femoral head protrudes medial to the ilioischial line. I — Iliac wings, ischium, and pubic rami: I systematically trace the pelvic ring. This begins at the pubic symphysis, follows the superior pubic ramus bilaterally, passes laterally to the acetabulum, then along the iliac crest, posteriorly to the SI joints, then inferiorly through the sacral ala. I then trace the inferior pubic rami and ischial tuberosities. KEY PRINCIPLE: the pelvic ring must break in TWO places — if I identify one fracture (e.g., a pubic ramus fracture), I MUST systematically search for the second disruption (opposite pubic ramus, SI joint disruption, acetabular fracture, or sacral fracture). P — Proximal femur: I assess both femoral necks for cortical integrity, trabecular patterns, and fracture lines. I look at the greater and lesser trochanters (avulsion fractures). The lesser trochanter is normally not prominent on AP view — if prominently visible, this suggests external rotation from a displaced NOF fracture. Finally, I assess the soft tissues — look for haematoma opacity adjacent to the hip, pelvic wall fat stripes, and any soft tissue calcification.

KEY POINTS TO SCORE

Technical adequacy: centred (coccyx over symphysis), both hips included, adequate exposure

SHIP: Shenton line, Hip joints, Iliac wings (pelvic ring), Proximal femur

Pelvic ring MUST break in TWO places — always find the second disruption

Prominent lesser trochanter on AP view suggests external rotation from displaced NOF fracture

Compare bilateral hip joints systematically for asymmetric pathology

COMMON TRAPS

✗Not checking technical adequacy before interpreting the radiograph

✗Not tracing Shenton line bilaterally

✗Finding one pelvic fracture and not looking for the second (ring principle)

✗Not assessing the femoral necks and trochanters systematically

Pelvis and Hip Imaging — Exam Day Reference

High-Yield Exam Summary

Systematic AP Pelvis (SHIP)

•Shenton line: smooth arc along inferior pubic ramus and medial femoral neck
•Hip joints: JSW more than 4mm, sphericity, osteophytes, subchondral changes
•Iliac wings and pelvic ring: ring must break in TWO places — always find the second
•Proximal femur: cortical integrity, trabecular pattern, trochanter avulsions

Occult NOF Fracture (PAIN)

•2-5% of NOF fractures have normal initial radiographs
•MRI within 24 hours: gold standard (sensitivity 99-100%)
•CT second-line (sensitivity approximately 80%) if MRI unavailable
•Garden I-II (non-displaced): fix. Garden III-IV (displaced): replace (elderly)

AVN Assessment

•MRI gold standard: detects Stage I (pre-radiographic) AVN
•Double line sign (T2): band of low signal + inner high signal = pathognomonic
•Crescent sign: subchondral fracture (Stage III) — indicates imminent collapse
•Bilateral in 50-80% of non-traumatic cases — always image BOTH hips

FAI Imaging

•Alpha angle more than 55-60 degrees = cam morphology
•LCEA more than 40 degrees = pincer overcoverage
•Crossover sign on AP pelvis = focal retroversion
•MR arthrography: sensitivity 87% for labral tears (vs 66% non-contrast MRI)

Systematic Pelvis and Hip Imaging Assessment

Pelvis/Hip Imaging Selection Guide

Clinical Scenario	First-Line Imaging	Advanced Imaging
Elderly hip pain after fall	AP pelvis + lateral hip radiograph	MRI within 24 hours if normal radiographs and clinical suspicion persists (occult NOF fracture). CT if MRI unavailable
Suspected acetabular fracture	AP pelvis + Judet views (45 degree obliques)	CT with 3D reconstruction for Letournel-Judet classification and surgical planning. MRI for associated labral/cartilage injury
Pelvic ring injury	AP pelvis + inlet/outlet views	CT for complete ring assessment (posterior ring is often underestimated on radiographs). Angiography if haemodynamically unstable
Suspected AVN	AP pelvis + frog lateral hip	MRI: gold standard for early AVN detection (pre-radiographic). Ficat-Arlet or Steinberg classification
Young adult hip pain (FAI)	AP pelvis + Dunn view (45 degree flexion lateral)	MR arthrography for labral assessment. CT for alpha angle measurement, head-neck offset ratio
Paediatric DDH	USS (less than 6 months) or AP pelvis (more than 6 months)	MRI if USS equivocal. Arthrography (fluoroscopic) for concentric reduction assessment during surgery

Neck of Femur Fracture Imaging

MRI for Occult NOF Fracture

Systematic Review

Carpenter CR, Schuur JD, Everett WW, Pines JM • Academic Emergency Medicine (2010)

Key Findings:

MRI had sensitivity of 99-100% and specificity of 100% for occult hip fracture.
CT sensitivity was approximately 80% for undisplaced fractures (inferior to MRI).
Delayed MRI (more than 24 hours) did not reduce sensitivity but delayed treatment, increasing morbidity.

Clinical Implication: MRI within 24 hours is the gold standard for suspected occult NOF fracture — failure to arrange MRI is a common medicolegal pitfall.

Limitation: MRI availability may limit timely imaging, particularly in rural settings. CT is an acceptable alternative.

Source: Carpenter CR et al. Acad Emerg Med 2010;17(5):488-98

Garden Classification and AVN Risk

Cohort Study

Garden RS • Journal of Bone and Joint Surgery (British) (1961)

Key Findings:

Garden I-II (non-displaced): AVN rate 8-15%. Internal fixation is the treatment of choice.
Garden III-IV (displaced): AVN rate 30-65%. In elderly patients, arthroplasty is preferred.
The trabecular pattern alignment on the AP view was the basis for the classification system.

Clinical Implication: The Garden classification determines management: non-displaced (I-II) fractures are fixed; displaced (III-IV) fractures in the elderly are replaced.

Limitation: Inter-observer reliability is moderate — many surgeons simplify to 'displaced' vs 'non-displaced'.

Source: Garden RS. JBJS Br 1961;43-B:647-63

NOF fracture imaging has direct management implications.