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HIP — Complete MS Orthopaedics Guide

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PART 1: CLINICAL EXAMINATION OF THE HIP

1.1 LOOK (Inspection)

1.2 FEEL (Palpation)

• Greater trochanter: tenderness → trochanteric bursitis, abductor enthesopathy
• ASIS, iliac crest: bony landmarks, avulsion injuries in young athletes
• Inguinal ligament: hernia, lymphadenopathy
• Femoral artery: palpable at the midpoint of the inguinal ligament (halfway between ASIS and pubic tubercle) — NOT the mid-inguinal point (halfway between ASIS and symphysis pubis, which overlies the deep inguinal ring)
• Intracapsular effusion cannot be palpated clinically due to depth

Exam point: Midpoint of inguinal ligament vs mid-inguinal point — commonly confused MCQ. Femoral artery = midpoint of inguinal ligament.

1.3 MOVE

1.4 SPECIAL TESTS — Must Know

Thomas Test (Fixed Flexion Deformity)

• Patient supine, flex opposite hip fully to obliterate lumbar lordosis
• Positive: Affected hip rises off table → reveals hidden fixed flexion deformity (compensated by hyperlordosis)
• Angle of rise = degree of fixed flexion deformity
• Reason: In OA, anterior capsule contracture and hip flexor spasm prevent full extension

Trendelenburg Test

• Ask patient to stand on one leg
• Negative (normal): Pelvis of the lifted side rises → abductors of stance leg are working
• Positive: Pelvis of the lifted side drops (or remains level) → abductors of stance leg are weak or inhibited

1. Abductor weakness (superior gluteal nerve palsy, polio)
2. Short lever arm (coxa vara, hip dysplasia)
3. Painful hip (inhibition)
4. Absent/non-union of greater trochanter

Leg Length Discrepancy (LLD)

• True shortening: Measured from ASIS to medial malleolus — shortening is in the limb itself
• Apparent shortening: Measured from umbilicus/xiphisternum to medial malleolus — due to pelvic obliquity from adduction contracture
• Anatomical levels to localise: Use Bryant's triangle, Nelaton's line, Schoemaker's line

FADIR Test (Flexion-Adduction-Internal Rotation)

• Positive = anterior hip impingement pain → femoroacetabular impingement (FAI)

FABER Test (Patrick's Test — Flexion-Abduction-External Rotation)

• Positive = groin/SI pain → FAI, labral tear, SI joint pathology

Ober Test

• Lateral decubitus, hip extended and abducted then released
• Positive = IT band tightness, iliotibial band syndrome

Logroll Test

• Patient supine, roll entire limb in/out — tests for hip pathology (pain with passive rolling = capsular irritation, e.g. septic arthritis, fracture)

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PART 2: FRACTURES OF THE HIP

2.1 ANATOMY RELEVANT TO HIP FRACTURES

• MCFA travels posteriorly along the femoral neck — displacement ruptures retinacular vessels
• The femoral head then depends only on the ligamentum teres artery (negligible in adults)
• Incidence of AVN after displaced femoral neck fractures: 15–35%

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2.2 FEMORAL NECK FRACTURES (Intracapsular)

Classification

Exam point: Garden I and II = stable; Garden III and IV = unstable. In practice, most surgeons now use a two-group system (undisplaced vs displaced) because interobserver reliability of the 4-grade system is poor. Rockwood & Green (2025) confirms that whether displaced or undisplaced is the key prognostic factor, not the subdivision.

Why Pauwels matters: Higher angle → more shear → higher fixation failure → important in young patients deciding between fixation and replacement.

• B1: Nondisplaced to minimally displaced subcapital
• B2: Transcervical
• B3: Displaced subcapital (most relevant clinically)

Management Algorithm

FEMORAL NECK FRACTURE
        ↓
Displaced or Undisplaced?
        ↓                  ↓
UNDISPLACED           DISPLACED
(Garden I/II)         (Garden III/IV)
        ↓                  ↓
Cannulated          Young patient (<65)?
screws (3 screws        ↓          ↓
in inverted tri)       YES         NO
                        ↓          ↓
              Urgent ORIF    Biologically
              (< 6–12 h)     active/active?
              + capsular        ↓          ↓
              decompression    YES         NO
                               ↓          ↓
                              THA      Hemiarthroplasty

• 3 parallel cannulated screws in an inverted triangle configuration
• Inferior screw positioned along inferior cortex — this is the tension side, critical for stability
• Posterior screw along posterior cortex resists retroversion displacement
• Avoid starting point distal to lesser trochanter → risk of subtrochanteric peri-implant fracture
• Varus malreduction = single biggest predictor of fixation failure
• Internal fixation failure rate: up to 30% overall

• Indicated for displaced fractures in elderly with moderate-high functional demands but comorbidities contraindicate THA
• Cemented femoral component is recommended (lower reoperation, less periprosthetic fracture risk)
• Bipolar > unipolar for hip function and acetabular erosion rates (Papavasiliou et al., 2023, PMID 35779144)
• DAA approach for hemiarthroplasty: lower dislocation rate, faster return to function (Manzo et al., 2023, PMID 37256391)

• Indicated for active/independent elderly patients with displaced fractures — best functional outcome
• Also preferred when pre-existing hip arthropathy (OA, RA)
• Higher dislocation risk than hemiarthroplasty
• DAA vs posterolateral for THA in femoral neck fractures: DAA = less blood loss, faster recovery; posterolateral = familiar territory, less neurovascular risk — network meta-analysis (Jin et al., 2023, PMID 37000019) shows comparable outcomes

Complications

1. AVN (15–35% displaced; 5–10% undisplaced)
2. Nonunion (~10–30% displaced if fixed)
3. Implant failure / varus collapse
4. Leg length discrepancy
5. Dislocation (THA > hemiarthroplasty)
6. Periprosthetic fracture
7. Infection

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2.3 TROCHANTERIC (EXTRACAPSULAR) FRACTURES

AO/OTA Classification of Trochanteric Fractures (31-A):

• Lateral femoral wall thickness < 20.5 mm on AP X-ray = thin/incompetent lateral wall
• Thin lateral wall → risk of wall blowout with DHS → recommend cephalomedullary nail (CMN)
• Systematic review (Selim et al., 2024, PMID 39183629): lateral wall thickness is a reliable predictor of fixation failure

• Shortened, externally rotated limb
• In A1: Fracture line from greater to lesser trochanter, intact medial cortex
• In A3: Reversed fracture line exiting below lesser trochanter laterally

Implants

TAD (Tip-Apex Distance): Sum of distance from screw tip to apex of femoral head on AP and lateral views. >25 mm → high cutout risk. This remains one of the most important technical parameters in hip fracture fixation.

Surgical Technique — DHS

1. Patient supine on fracture table, traction + internal rotation to reduce fracture
2. C-arm confirmation of reduction (AP + lateral)
3. Small lateral incision over the femur, split of vastus lateralis
4. Guide wire inserted at 135° angle — confirmed center-center on AP, inferior on lateral
5. TAD measurement to confirm ≤ 25 mm
6. Reaming over guide wire
7. Lag screw insertion
8. Barrel plate attached and fixed with cortical screws
9. Compression screw applied
10. Close in layers

• Avoid varus reduction
• Avoid posterior malreduction (anteverts head, risks cutout)
• Do not remove guide wire until lag screw secure
• Confirm TAD on both views before closure

Surgical Technique — CMN (PFN/PFNA)

1. Patient supine on fracture table or lateral
2. Reduction confirmed under fluoroscopy
3. Trochanteric entry point (piriformis or trochanteric tip depending on nail design)
4. Ream the entry portal, insert nail
5. Proximal locking screw (helical blade or lag screw) under fluoroscopy into femoral head — center-center AP, inferior-central lateral
6. Distal static or dynamic locking
7. End cap insertion

• Avoid medialization of femoral shaft (a3 fracture risk)
• Piriformis entry nail: Risk of AVN in young → use trochanteric entry design instead
• Correct rotational alignment before distal locking

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2.4 SUBTROCHANTERIC FRACTURES

• I: Undisplaced
• II: Two-part (A: transverse; B: spiral with lesser troch intact; C: spiral with lesser troch as third fragment)
• III: Three-part (A: two proximal fragments + shaft; B: includes lesser trochanter)
• IV: Comminuted ≥4 fragments
• V: Subtrochanteric + intertrochanteric extension

• Proximal fragment is flexed (iliopsoas), abducted (abductors), externally rotated (short external rotators)
• Makes anatomical reduction technically challenging
• Long CMN is treatment of choice

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2.5 HIP DISLOCATIONS

Posterior Dislocation (90% of hip dislocations)

• I: Pure dislocation, no/small fragment
• II: Single large posterior wall fragment
• III: Comminuted posterior wall fragments
• IV: Acetabular floor fracture
• V: Femoral head fracture (Pipkin fracture)

• Urgent closed reduction within 6 hours — delay increases AVN risk
• Bigelow's maneuver (traction-flexion-internal rotation-abduction)
• Stimson technique (prone, gravity-assisted)
• Post-reduction CT mandatory to detect intra-articular fragments
• Residual instability or irreducible → ORIF

Anterior Dislocation (10%)

• Superior (pubic): Hip extended, leg externally rotated
• Inferior (obturator/thyroid): Hip flexed, externally rotated

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2.6 ACETABULAR FRACTURES

1. Posterior wall
2. Posterior column
3. Anterior wall
4. Anterior column
5. Transverse

1. T-shaped
2. Posterior column + posterior wall
3. Transverse + posterior wall
4. Anterior column/wall + posterior hemitransverse
5. Both columns (floating acetabulum — most common associated type in elderly)

• Medial roof arc > 45°
• Anterior roof arc > 25°
• Posterior roof arc > 70°
• If all met → surgical management NOT required

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PART 3: SURGICAL APPROACHES TO THE HIP

3.1 Posterior / Southern Approach (Moore/Gibson)

1. Lateral decubitus position
2. Skin incision: Posterolateral, centered on greater trochanter
3. Incise iliotibial band and gluteus maximus split
4. Identify short external rotators (tag for later repair)
5. Incise external rotators and posterior capsule
6. Hip dislocated anteriorly with flexion-IR

3.2 Direct Anterior Approach (DAA / Smith-Petersen / Heuter)

1. Supine on standard or Hana/ProFx table
2. Incision from ASIS, angled laterally over TFL
3. Develop interval between TFL and sartorius
4. Incise rectus femoris reflected/direct heads
5. T-shaped capsulotomy
6. Hip dislocated

3.3 Anterolateral Approach (Watson-Jones)

• Used for hemiarthroplasty, irreducible dislocations, associated femoral neck fracture with dislocation
• Less abductor damage than lateral approaches

3.4 Direct Lateral / Transgluteal Approach (Hardinge/McFarland-Osborne)

• Commonly used for THA
• Risk: Superior gluteal nerve damage if split extends >5 cm above GT → Trendelenburg gait

3.5 Kocher-Langenbeck Approach

• Standard approach for posterior wall and posterior column acetabular fractures
• Patient prone or in lateral decubitus
• Critical structure at risk: Sciatic nerve (runs medial to short external rotators)
• Protect by: keeping the knee flexed during surgery, direct visualization

3.6 Ilioinguinal Approach (Judet-Letournel)

• For anterior column, anterior wall, both-column fractures
• Structures at risk: External iliac vessels, femoral nerve (lateral window), corona mortis (anastomosis between obturator and external iliac at middle window), lymphatics

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PART 4: COLD CASES IN HIP ORTHOPAEDICS

4.1 Avascular Necrosis (Osteonecrosis) of Femoral Head

• Alcohol
• Steroids (most common iatrogenic)
• Idiopathic
• Caisson disease (decompression sickness)
• Hemoglobinopathies (sickle cell), also: SLE, Gaucher's, hyperlipidaemia, radiotherapy, HIV, hypercoagulable states

• Stage I–II: Core decompression ± bone graft (decompresses intraosseous pressure, promotes revascularisation), bisphosphonates, protected weight bearing
• Stage III: Core decompression + fibular strut graft or vascularised fibular graft; osteotomy (rotate necrotic segment away from weight-bearing zone)
• Stage IV–VI: THA (definitive treatment)

4.2 Perthes Disease (Legg-Calvé-Perthes)

• Age: 4–10 years, boys:girls = 4:1
• AVN of femoral head in a child, idiopathic
• Catterall classification (I–IV based on extent of head involvement)
• Herring lateral pillar classification (A/B/B-C/C based on height of lateral pillar)
• Treatment: Containment (keep femoral head within acetabulum while reossification occurs) — abduction brace, femoral/pelvic osteotomy for Herring B/C and age >8

4.3 Slipped Capital Femoral Epiphysis (SCFE)

• Age: 11–16 years, obese boys
• Epiphysis displaces posteriorly and medially (metaphysis appears to displace anterolaterally — the "ice cream falling off the cone")
• Classified: Stable (can weight-bear) vs Unstable (cannot weight-bear — higher AVN risk)
• Southwick slip angle on frog-leg lateral
• Treatment: In-situ pinning with single cannulated screw (even for stable SCFE, do not attempt reduction — increases AVN risk)

4.4 Developmental Dysplasia of the Hip (DDH)

• Spectrum from instability to frank dislocation
• Barlow test (dislocatable), Ortolani test (reduce a dislocated hip)
• Ultrasound for infants (Graff classification: Type I = normal; II = immature; III/IV = dysplastic)
• Treatment: Pavlik harness (0–6 months); closed reduction + hip spica (6–18 months); ORIF ± osteotomy (>18 months)

4.5 Septic Arthritis of the Hip

1. Fever > 38.5°C
2. Non-weight-bearing
3. ESR > 40 mm/hr
4. WBC > 12,000/mm³ (+CRP > 2 mg/dL as 5th criterion)

4.6 Femoroacetabular Impingement (FAI)

4.7 Periprosthetic Hip Fractures (Vancouver Classification)

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PART 5: RECENT EVIDENCE AND NEW MODALITIES

5.1 Surgical Timing

• HIP ATTACK RCT: Accelerated surgery (median 6 h) vs standard care (24 h) — no difference in mortality or major complications. Supports operating within 24–48 h as standard.
• British Hip Fracture Database: 10% increase in 30-day mortality per 24-hour delay.
• Current consensus: Operate within 36–48 h after medical optimisation.

5.2 Implant Advances

• Helical blade (PFNA) vs lag screw in CMN: Blade achieves rotational stability by compaction not cutting; preferred in osteoporotic bone
• Dual-lag screw systems (Intertan, Synthes): Two interlocked screws provide rotational control in femoral head
• Augmentation: Calcium phosphate or PMMA cement augmentation of lag screw in severe osteoporosis — early evidence supports in high-risk patients
• Medoff Plate: Two-way sliding plate for reversed oblique (A3) fractures — allows collapse in two planes; evidence remains limited but positive

5.3 Arthroplasty Advances

• Dual-mobility cups: Dramatically reduce dislocation risk in THA for femoral neck fractures — becoming standard in many centres
• Cementless THA for femoral neck fractures: Recent RCTs (HEALTH, Devereaux 2020) support THA over hemiarthroplasty in active elderly — ongoing debate on cemented vs cementless femoral stem
• Robotic-assisted THA: Improved cup positioning accuracy → theoretically lower dislocation rates; RCT evidence still maturing

5.4 Perioperative Care (Hip Fracture Programs)

• Orthogeriatric co-management (shared care models): Associated with 30–40% reduction in mortality and complications
• Cemented femoral stem in hemiarthroplasty for femoral neck fractures: Recommended over press-fit — lower reoperation rate, lower periprosthetic fracture risk (Miller's Review 9th ed)
• Anticoagulation: DOAC patients — surgery usually delayed 1–2 days; warfarin patients — some centres operate without reversal if INR < 1.5. LMWH thromboprophylaxis for minimum 28 days post-operatively.
• Preoperative traction: No longer recommended — no benefit for pain, reduces femoral head perfusion (arteriographic evidence)

5.5 Outcome Predictors

• Clinical Frailty Scale (CFS): Rockwood CFS 1–3 (robust) → target return to independence; CFS 7–9 (severe frailty) → surgery as pain palliation and dignified end-of-life care
• 30-day mortality after hip fracture: ~5–10% in well-run centres; 1-year mortality: ~20–30%
• Return home at 1 year: ~50–60% of community-dwelling patients
• New Mobility Score (NMS): Best validated instrument for pre- and post-fracture mobility assessment in hip fracture patients

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PART 6: EXAM MEMORY AIDS

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