Fractures Around the Hip
Orthopaedics · Trauma · lean revision notes
Fractures Around the Hip
Fractures around the hip span the proximal femur from the femoral head to about 5 cm below the lesser trochanter. They are a NEET PG favourite because of two recurring decision points: does the blood supply to the head survive? and which implant fits this fracture in this patient? Master the blood supply, the Garden classification, and the age-based fixation-versus-replacement algorithm, and most questions fall.
Anatomy & Blood Supply to the Femoral Head
The femoral head receives blood from three sources, and the relative dominance of each explains the avascular necrosis (AVN) risk that dominates this topic.
| Source | Vessel | Importance |
|---|---|---|
| Medial & lateral circumflex femoral arteries (from profunda femoris) | Form an extracapsular arterial ring, give off retinacular vessels (ascending cervical branches) | Most important in adults; medial circumflex dominant |
| Artery of ligamentum teres | Branch of obturator/medial circumflex | Negligible in adults; important in children |
| Intramedullary (metaphyseal) vessels | Ascend through the neck | Disrupted by displaced neck fractures |
High-yield: The medial femoral circumflex artery (its deep branch forming the lateral epiphyseal/retinacular vessels) is the chief supply to the adult femoral head. A displaced intracapsular neck fracture tears the retinacular vessels → AVN.
Because the supply runs up the neck from below the capsule, a fracture inside the capsule (subcapital/transcervical) threatens it, whereas an intertrochanteric fracture is extracapsular and rarely causes AVN — it has a rich metaphyseal blood supply and unites readily.
High-yield: Intracapsular (neck) fractures → risk of AVN and non-union. Extracapsular (intertrochanteric/subtrochanteric) → risk of malunion (coxa vara) and shortening, but union is reliable.
Classification of Hip Fractures (Anatomical)
Femoral head → neck (intracapsular) → intertrochanteric (extracapsular) → subtrochanteric.
- Femoral neck (intracapsular): subcapital, transcervical, basicervical (basicervical is functionally extracapsular).
- Intertrochanteric: between greater and lesser trochanters; extracapsular.
- Subtrochanteric: within 5 cm distal to the lesser trochanter.
Femoral Neck Fractures
Garden Classification (degree of displacement)
The single most asked classification. Based on the AP radiograph and the trabecular pattern.
| Garden type | Description | Displacement | AVN risk |
|---|---|---|---|
| I | Incomplete / valgus impacted | Undisplaced | Low |
| II | Complete, undisplaced | Undisplaced | Low |
| III | Complete, partial displacement (trabeculae malaligned, capsule/retinaculum partly intact) | Displaced | High |
| IV | Complete, full displacement (head free in acetabulum, trabeculae parallel again) | Displaced | Highest |
High-yield mnemonic — "1234 = One, Two = stick; Three, Four = fix or replace." Garden I & II are undisplaced (treated by fixation); Garden III & IV are displaced (decision hinges on age).
High-yield: A useful simplification used in exams — Garden I/II = undisplaced, III/IV = displaced. The practical management split is undisplaced vs displaced rather than all four grades.
Pauwels Classification (verticality / shear)
Based on the angle of the fracture line from the horizontal — predicts shear and non-union, guides fixation.
| Pauwels type | Angle from horizontal | Biomechanics |
|---|---|---|
| I | < 30° | Mostly compression; stable |
| II | 30–50° | Mixed |
| III | > 50° | Maximal shear → highest non-union risk → needs angle-stable device (e.g. fixed-angle plate) |
High-yield: Higher Pauwels angle → more vertical fracture → more shear → more non-union. Pauwels III may need a fixed-angle device rather than simple cancellous screws.
Clinical Features
- Elderly patient (often osteoporotic woman) after a trivial fall; young patient after high-energy trauma.
- Pain in groin, inability to bear weight.
- Classic sign: limb shortened and externally rotated (less external rotation than intertrochanteric — about 45–60° vs full 90° because the intact capsule limits it).
- Tenderness in the groin/over the femoral triangle; pain on axial loading and rotation.
- Impacted/Garden I fractures may allow walking — beware the patient who is still ambulant.
Investigation of Choice
- First-line: AP pelvis + cross-table lateral radiograph of the hip. AP with the limb in 15–20° internal rotation profiles the neck best.
- Occult/suspected fracture with normal X-ray: MRI is the investigation of choice (most sensitive, picks up within hours). CT is an alternative if MRI unavailable.
High-yield: Clinically suspected hip fracture + normal radiograph → get an MRI (best for occult femoral neck fracture). Do not discharge.
Management — Age & Displacement Drive Everything
Stepwise approach: Confirm fracture → assess displacement (Garden) → assess age & physiological status → choose fixation vs arthroplasty → operate early (< 48 h).
Young patient (< 60–65 y) — preserve the head:
- Surgical emergency. Displaced neck fracture in the young → urgent anatomical closed/open reduction + internal fixation (cancellous cannulated screws, or a fixed-angle device for vertical Pauwels III). Aim to operate within 6–12 hours to reduce AVN risk.
- Even displaced fractures are fixed (not replaced) to save the native head.
Elderly patient:
- Undisplaced (Garden I/II): Internal fixation with multiple cancellous cannulated screws (inverted triangle configuration).
- Displaced (Garden III/IV): Arthroplasty.
- Low-demand, frail, limited mobility → Hemiarthroplasty (e.g. bipolar/Austin-Moore/Thompson).
- Active, independent, good cognition, longer life expectancy → Total hip replacement (THR) — better functional outcome and lower revision/groin pain.
| Patient | Fracture | Implant of choice |
|---|---|---|
| Young (<60) | Any neck fracture | Reduction + internal fixation (cannulated screws) |
| Elderly | Undisplaced (Garden I/II) | Cannulated screws |
| Elderly, low-demand/frail | Displaced (III/IV) | Hemiarthroplasty |
| Elderly, active/independent | Displaced (III/IV) | Total hip replacement |
High-yield: Displaced femoral neck fracture in the elderly → arthroplasty (replace), not fixation. Fixation has unacceptable rates of AVN and non-union; replacement gives early mobilisation. In the young, the same fracture is fixed to preserve the head.
High-yield: Austin-Moore = uncemented (fenestrated stem, needs good bone), Thompson = often cemented; both are unipolar hemiarthroplasties. Bipolar prostheses have an additional inner bearing reducing acetabular wear.
Complications of Neck Fractures
- Avascular necrosis of the femoral head (commonest worry; presents months later with groin pain, may need THR).
- Non-union (up to ~30% in displaced fractures) — vertical Pauwels III especially.
- Implant cut-out, fixation failure.
- Post-traumatic osteoarthritis.
Intertrochanteric Fractures
Extracapsular fracture between the trochanters, typically in older osteoporotic patients after a fall. Highly vascular cancellous bone → unites well, AVN and non-union are rare. The challenge is mechanical stability, not biology.
Clinical Features
- Severe pain, gross inability to move.
- Marked shortening with full (90°) external rotation — more external rotation than neck fractures because the fracture is extracapsular and the iliopsoas pulls the distal fragment.
- Often more swelling/bruising than intracapsular fractures (extracapsular bleeding → can lose significant blood; watch for anaemia/hypovolaemia).
Classification — Boyd & Griffin / Evans
- Stable vs unstable is what matters. Stability depends on the integrity of the posteromedial cortex (calcar). Loss of posteromedial buttress, reverse obliquity, or subtrochanteric extension → unstable.
- Evans classification: based on fracture line direction and ability to reduce/restore the posteromedial cortex; reverse obliquity = unstable and behaves like a subtrochanteric fracture.
Investigation
- AP pelvis + lateral hip radiograph is usually diagnostic. Traction/internal-rotation views help plan. CT for comminution if needed.
Management — Implant of Choice
Stepwise: Assess stability (posteromedial cortex / obliquity) → choose DHS for stable, intramedullary nail for unstable → fix early, mobilise.
| Pattern | Implant of choice |
|---|---|
| Stable intertrochanteric | Dynamic Hip Screw (DHS) — sliding screw + side plate; allows controlled collapse and impaction at the fracture |
| Unstable (comminuted, reverse obliquity, subtroch extension) | Cephalomedullary / intramedullary nail (e.g. PFN, PFNA, Gamma nail) |
High-yield: Stable intertrochanteric → DHS. Unstable / reverse-oblique → intramedullary (cephalomedullary) nail (PFN). A DHS used on a reverse-oblique fracture fails (medialises the shaft).
High-yield: Tip–Apex Distance (TAD) predicts DHS screw cut-out. Keep TAD < 25 mm (sum of distances from screw tip to apex on AP + lateral). High TAD → cut-out, the commonest mode of DHS failure.
High-yield: Goal in the elderly is early mobilisation and weight-bearing to avoid the lethal complications of recumbency (pneumonia, DVT/PE, pressure sores). Operate within 24–48 h when fit.
Complications
- Coxa vara and limb shortening (malunion) — the classic intertrochanteric complication.
- Screw cut-out from the head (high TAD), implant failure.
- Anaemia from blood loss; medical complications of immobility.
Subtrochanteric Fractures
Fracture within 5 cm distal to the lesser trochanter, a region of high biomechanical stress (large compressive medial and tensile lateral forces).
- Deforming forces are characteristic: the proximal fragment is flexed (iliopsoas), abducted (glutei) and externally rotated (short rotators), while the distal fragment is adducted and shortened (adductors). Reduction is therefore difficult.
- Causes: high-energy trauma in the young; low-energy/pathological in the elderly. Atypical femoral fractures from long-term bisphosphonate use classically occur in the subtrochanteric/diaphyseal region (transverse fracture, lateral cortical beaking, prodromal thigh pain).
- Implant of choice: long cephalomedullary intramedullary nail (load-sharing, biomechanically superior in this high-stress zone). Plates are second-line.
High-yield: Suspect an atypical femoral fracture (bisphosphonate-associated) in a patient on long-term bisphosphonates presenting with a transverse subtrochanteric fracture, lateral cortical thickening/beaking and antecedent thigh pain — image the contralateral femur too.
High-yield: Subtrochanteric fracture → long intramedullary nail; remember the flexed–abducted–externally rotated proximal fragment deformity.
Key Differentials & Comparison
The most tested comparison is intracapsular (neck) vs extracapsular (intertrochanteric).
| Feature | Femoral neck (intracapsular) | Intertrochanteric (extracapsular) |
|---|---|---|
| Age | Younger old / can be young trauma | Older, more osteoporotic |
| Blood supply | Tenuous (retinacular) | Rich metaphyseal |
| AVN / non-union | High | Rare |
| Union | Poor in displaced | Reliable |
| External rotation | Partial (~45–60°) | Full (90°) |
| Bruising/blood loss | Less (contained by capsule) | More |
| Implant | Screws or arthroplasty | DHS / IM nail |
| Late complication | AVN, non-union | Coxa vara, shortening |
Other differentials of the painful, non-weight-bearing hip in the elderly: pubic ramus fracture, acetabular fracture, pathological fracture/metastasis, septic arthritis, soft-tissue contusion, occult fracture (needs MRI).
Recently asked / exam angle
- Blood supply of the femoral head — answer medial femoral circumflex / lateral epiphyseal (retinacular) vessels; ligamentum teres important in children.
- Garden classification — match grade to displacement; "Garden III/IV = displaced."
- Pauwels III = most vertical, highest non-union.
- Implant matching: stable intertroch → DHS; unstable/reverse-oblique or subtroch → PFN/cephalomedullary nail; displaced neck in elderly active patient → THR, frail → hemiarthroplasty; young displaced neck → emergency fixation.
- Tip-Apex Distance < 25 mm to avoid screw cut-out (single-best-answer favourite).
- Investigation of occult hip fracture = MRI.
- Atypical femoral fracture with bisphosphonates — site and radiographic features.
- Austin-Moore (uncemented) vs Thompson (cemented) hemiarthroplasty; unipolar vs bipolar.
- Sign of neck fracture: shortened, externally rotated limb; image-based questions on trabecular pattern.
Rapid revision
- Medial femoral circumflex artery (retinacular branches) = chief supply to the adult femoral head; ligamentum teres matters only in children.
- Intracapsular = AVN + non-union; extracapsular = malunion (coxa vara) + shortening.
- Garden: I incomplete/impacted, II complete undisplaced, III partial displacement, IV full displacement; III & IV = displaced.
- Pauwels III (>50°) = most vertical, maximal shear, highest non-union.
- Young + displaced neck = surgical emergency → urgent reduction + cannulated screws.
- Elderly + displaced neck → arthroplasty: frail = hemiarthroplasty, active = total hip replacement; undisplaced = cannulated screws.
- Stable intertrochanteric → DHS; unstable/reverse-oblique → cephalomedullary (PFN) nail.
- Tip-Apex Distance < 25 mm prevents DHS screw cut-out.
- Subtrochanteric → long IM nail; proximal fragment is flexed, abducted, externally rotated.
- Bisphosphonate atypical fracture = transverse subtrochanteric, lateral cortical beaking, prodromal thigh pain.
- Occult hip fracture with normal X-ray → MRI (investigation of choice).
- Neck fracture = partial external rotation (~45–60°); intertrochanteric = full 90° external rotation with more blood loss; operate within 24–48 h to enable early mobilisation.