O&T SC053: A Painful Hip: Hip Problems Flashcards
Hip joint
- Ball and socket joint
- Acetabulum in pelvis, Femoral hip ball in femur
- Covered with hyaline cartilage
- Labrum: layer of fibrocartilage —> increase contact area with femoral hip ball
Capsule:
1. Iliofemoral ligament
2. Pubofemoral ligament
3. Ischiofemoral ligament
—> they are not distinct ligament
Hip muscles:
Front:
1. Iliopsoas (most important, principal hip flexor)
2. Pectineus
3. Adductor longus
4. Rectus femoris
5. Tensor fascia latae
Side:
1. Gluteus medius (hip abduction)
2. Gluteus maximus (bulk of buttock, hip extension)
3. Gluteus minimus
4. Piriformis (entrapment of sciatic nerve, DDx of sciatica)
Artery:
1. Femoral artery
—> Profunda femoris —> Lateral + Medial femoral circumflex artery —> supply Proximal femur (Avascular necrosis)
Nerves:
1. Femoral nerve
2. Obturator nerve
3. Sciatic nerve
X-ray:
1. **Shenton’s line
—> **smooth arc from Medial border of proximal femur to Inferior border of superior pubic ramus (Rmb)
2. ***Trabecular patterns of proximal femur
- formed by compressive force through femur (15o from vertical midline) / tensile force
—> detect any slight fracture (when fracture line cannot be even seen)
Biomechanics:
- Subject to 3x body weight during single-legged stance
—> ∵ Weight of body + Forces created by muscle contraction to balance the trunk
- We walk an average of 1000000-4000000 cycles every year
***Causes of Hip pain
- Intrinsic
- Hip
—> Child
—> Adult - Extrinsic (Radiation / Referred pain)
- Lumbar spine
- Knee
- Others (e.g. Groin hernia, Herpes zoster)
Hip Development in Child
Birth:
- Acetabulum: 3 pieces of bone —> joined by Triradiate cartilage
- Femur: **No Capital femoral epiphysis (wholly cartilage at birth), **No physis
Child:
- Femur: ***Physis form, Capital femoral epiphysis gradually form (~2-4 yo) —> become a ball (~8-9 yo) —> Physis fuses when reaches skeletal maturity
***Causes of Hip pain in Child
- Septic arthritis, Osteomyelitis
- Transient synovitis
- Perthes’ disease
- Slipped capital femoral epiphysis
- Primary bone tumours
- Juvenile chronic arthritis
- Septic arthritis, Osteomyelitis
Routes:
1. Direct invasion / inoculation
2. Local spread (e.g. abscess)
3. Haematogenous
- Septic arthritis
—> Babies <2 (∵ artery can reach end of bone (subarticular region: very close to joint), no physis, no capital femoral epiphysis)
—> Adults
- Osteomyelitis (children)
—> Children (∵ artery cannot penetrate physis —> stasis of blood flow in metaphysis)
Causative agents:
- TB
- Other bacteria
- Transient synovitis
- Idiopathic, self-limiting
- Diagnosis of exclusion
- “Irritable hip”
- Usually 6-12 yo, otherwise healthy
- Pain, limp, slight wasting, extremes of all movements limited
- Symptoms last 1-2 weeks then subside spontaneously
Septic arthritis vs Transient synovitis (SpC Revision)
Septic arthritis:
- Less common
- High WCC, ESR, CRP
- High fever
- Septic looking
- Unable to bear any weight
- May have referred knee pain
- Deteriorates without treatment
Transient synovitis:
- Common
- Mild raised WCC, ESR, CRP
- Low grade fever
- History of URTI (e.g. 2 weeks prior)
- Restricted hip ROM
- May have referred knee pain
- Improves with analgesics
- Perthes’ disease
- ***4-8yo
- M:F = 4:1
- ~Avascular necrosis in adults
- Ischaemia of femoral head due to problem of blood supply to Capital femoral epiphysis
1. **Metaphyseal vessels (until 3-4 yo —> ∵ physis formed)
2. **Lateral epiphyseal vessels (closely related to joint capsule)
3. ***Vessels in ligamentum teres (not fully developed until 8)
—> i.e. 4-8 yo —> blood only from 1 source (i.e. Lateral epiphyseal vessels) —> any disruption will cause ischaemia
Stages:
1. Ischaemia + bone death
2. Revascularisation + repair —> lead to fragmentation of capital femoral epiphysis + distortion of anatomy
3. Distortion + remodeling
- adequate treatment —> original form
- no treatment —> poor remodeling —> early OA in young adults
- Slipped capital femoral epiphysis (SCFE)
- Usually **boys **14-16 yo (approaching ***skeletal maturity)
- Hormonal imbalance —> delay in ossification of physis —> intrinsic weakness of physis (physeal disruption at hypertrophic zone) —> abnormal movement along physis —> whole CFE will slip downwards
- Fat + sexually immature, Excessively tall + thin
- Leg externally rotated + short, limited flexion, abduction, medial rotation
X-ray:
- ***Klein’s line
—> Line along superior border of lateral neck of femur should always cut through CFE
—> SCFE: line will miss CFE
***Causes of Hip pain in Adults
- ***OA (2nd common)
- Femoro-Acetabular impingement (FAI)
- Labral tear - ***Inflammatory arthritis
- RA
- Ankylosing spondylitis - ***Avascular necrosis of femoral head (most common)
- ***Primary / Secondary bone tumours
- ***Osteoporotic fracture of proximal femur
- Bursitis, Tendinitis, Muscle sprain
(Other DDx:
- Hip fracture
- Pubic rami fracture)
- Osteoarthritis
Causes:
1. Primary (uncommon in Chinese)
2. Secondary
- **Trauma
- **Infection
- ***Inflammatory
- Crystal deposition
- Neuropathic (e.g. Charcot joint)
- Metabolic / Endocrine
- Congenital
- Femoro-Acetabular impingement (FAI)
Pathological changes (**Kellgren + Lawrence scoring system):
1. **Narrowing of joint space
2. **Marginal osteophytes
3. **Subchondral sclerosis
4. ***Subchondral cyst
Femoro-Acetabular impingement (FAI):
- Young adults
- Hip joint not well formed —> Extra bone grows along femur / acetabulum / both —> irregular shape of hip joint
—> Too much bone in Acetabulum (Pincer type) —> entry of acetabulum too tight —> damage cartilage of femoral head
—> Too much bony lump in femoral head / neck (Cam type) —> impingement on periphery of acetabulum
Labral tears:
- Labrum: a band of tough cartilage and connective tissue that line acetabular ***rim
- A lot may not be clinically important —> no need treatment
Causes:
- Idiopathic
- Degenerative
- Traumatic
Symptoms:
- Asymptomatic
- Groin pain
Treatment:
1. Education + Lifestyle modification
- ***Weight loss
- Walking aids
- Physiotherapy
- **Muscle strengthening
- **ROM exercise
- Cardiopulmonary function, endurance - Analgesic
- NOT affect natural history
- **Paracetamol (1st line)
- **NSAIDs (Non-selective vs Selective)
—> Pain relief + Anti-inflammatory (synovitis, bone marrow lesions, etc.)
- Tramadol: non-narcotic
—> Combine with paracetamol: synergistic
—> If CI to NSAIDs
- Opioids
—> CNS depression, addiction
—> No routine use - Glucosamine / Chondroitin
- Components of articular cartilage
—> Glucosamine: amino sugar
—> Chondroitin: proteoglycan
- Dietary supplement
- ?Cartilage regeneration, decrease degradation
- SE: uncommon, GI: increase GI gas, soft stool, nausea, diarrhoea, abdominal pain - Intraarticular hyaluronic acid
- Avoid (strong evidence against use) - Intraarticular steroid
- Anti-inflammatory effect
- Slight ↑ infection risk if surgery is performed within 3 months - Surgery
- ***Total hip replacement
Non-selective COX1 inhibitor vs Selective COX2 inhibitor
Non-selective COX1 inhibitor:
- GI toxicity (gastritis, ulceration)
- Nephrotoxicity (impair RFT)
Selective COX2 inhibitor:
- Reduced GI toxicity ~ 50%
- Cardiovascular toxicity
—> Inhibit vasodilation —> hypertension —> heart attack
—> Reduce anti-platelet function of Aspirin
- in HK: only Celebrex (Celecoxib), Arcoxia (Etoricoxib) available
Indication:
- COX1 contraindication: GI bleeding
- Warfarin
- Rheumatoid arthritis
- Synovitis (uncontrolled inflammation)
- Multiple joints affected (peripheral joints vs axial joints in AS)
Pathological changes:
- Osteopenia (∵ increased in blood supply washing away Ca content)
- Periarticular erosion (erosion in margin of joint where synovium is attached)
- Joint space narrowing
- Soft tissue swelling
- Joint subluxation / deformity
- End stage: Secondary OA
- Larsen’s classification: 0-5
- Ankylosing spondylitis
- Male predominant
- Axial skeleton
—> “Bamboo” spine
—> SI joint
—> Hip joint - HLA-B27 positive
- Avascular necrosis of femoral head (股骨頭壞死 / 骨枯)
Most common cause for hip surgery
Causes:
1. Primary (Idiopathic)
2. Secondary (STARS: Steroid, Trauma, Alcohol, Radiation, Scuba / Sickle cell disease)
- **Trauma (Displaced femoral neck fracture / Fracture dislocation of hip —> disruption of circumflex artery (esp. medial femoral circumflex artery (MFCA)))
- **Steroid (∵ lipid metabolism affected —> abnormally large lipocytes within bone marrow —> intramedullary pressure too high —> shut off microcirculation)
- **Chronic alcoholism (∵ lipid metabolism affected —> abnormally large lipocytes within bone marrow —> intramedullary pressure too high —> shut off microcirculation)
- **Caisson disease (Decompression sickness)
- **Sickle cell disease
- Gaucher disease
- **Vasculitis
- Infection
Clinical features:
- Reduced ROM
- Difficulty flexion of hip (walking upstairs with good hip first then walking downstairs with bad hip first (好人上天堂, 壞人落地獄))
- Hip pain
X-ray:
1. **Cyst
- resorption of dead bone + replacement with fibrous + granulation tissue
2. **Sclerosis
- thickened trabeculae due to direct deposition of new bone onto dead bone
3. ***Crescent sign
- subchondral collapse of the necrotic segment
(4. Flattening of femoral head
5. Preservation of joint space (i.e. not OA)
6. Preservation of acetabulum)
MRI:
- 99% sensitivity + specificity
Staging:
- Early (Femoral head still round)
- Intermediate (***Crescent sign —> indicate Subchondral fracture ∵ no blood supply)
- Late (Femoral head collapse)
**Ficat classification:
Stage 1:
- **Pre-radiological on X-ray, **only changes on MRI
- MRI of contralateral hip
- Regeneration of bone, very slow
—> **Avoid risk factors, heavy weight bearing, Walking aids (prevent AVN in contralateral side)
—> **Bisphosphate (treat osteoporosis, lack evidence)
—> **Core decompression (increased intra-medullary pressure, re-vascularisation, bone regeneration)
Stage 2:
- X-ray changes
- **Sclerotic + Cystic changes
- **Crescent sign (subchondral radiolucency)
—> **Core decompression / **Vascularised bone graft (debridement of necrotic bone, autograft, allograft, artificial bone graft)
Stage 3:
- **Femoral head collapse
- Normal joint space
—> **Vascularised bone graft / ***Total hip replacement (quick + reliable procedure, improving implant survivorship) (hemiarthroplasty less favourable long term outcome due to risk of revision in the future)
Stage 4:
- **Secondary OA
—> **Total hip replacement
