วันศุกร์ที่ 8 พฤษภาคม พ.ศ. 2569

Hemarthrosis

Hemarthrosis

Definition

Hemarthrosis = bleeding into joint cavity

เป็นสาเหตุสำคัญของ:

  • acute monoarthritis
  • painful swollen joint

Definitive diagnosis:

arthrocentesis


Causes of Hemarthrosis

แบ่งเป็น:

  • traumatic
  • nontraumatic

1. Traumatic Hemarthrosis

สาเหตุพบบ่อยที่สุด

Clinical clue

  • swelling within hours after injury
  • severe pain
  • rapid effusion (<12 hr)

Rapid swelling suspect:

  • ligament injury
  • osteochondral fracture
  • intraarticular fracture

Knee Hemarthrosis (high-yield)

Most common mechanism:

  • twisting injury on loaded knee

Common associated injuries

Injury

Approximate frequency

ACL tear

~70%

Meniscal tear

~10%

Patellar subluxation/dislocation

10–15%

Osteochondral fracture

2–5%


Physical examination

ตรวจ:

  • joint line tenderness
  • patella tenderness
  • ligament stability

Tests:

  • valgus/varus
  • anterior drawer/Lachman
  • posterior drawer

Imaging

Initial

  • plain radiograph

Knee views:

  • AP
  • lateral
  • patellar
  • tunnel

CT

ใช้เมื่อ:

  • fracture suspected but X-ray negative

MRI

ดีที่สุดสำหรับ:

  • ligament
  • meniscus
  • cartilage

Lipohemarthrosis

Definition

fat + blood in joint

Suggests:

intraarticular fracture


Diagnosis

  • arthrocentesis
  • CT/MRI
  • X-ray fluid-fluid level

Double fluid-fluid level more specific


Hemarthrosis after Minimal Trauma

ให้คิดถึง:

  • hemophilia
  • coagulation disorder
  • acquired factor inhibitor

ถ้าไม่มี bleeding disorder:

  • ACL tear
  • meniscal tear ยังเป็นไปได้

Postoperative Hemarthrosis

พบได้หลัง:

  • TKA
  • arthroscopy

Cause พบบ่อย:

  • hypertrophic synovium impingement

Treatment:

  • synovectomy
  • embolization

2. Nontraumatic Hemarthrosis

Important causes:

  • bleeding disorders
  • anticoagulants
  • OA/chondrocalcinosis
  • neuropathic joint
  • septic arthritis
  • vascular lesions
  • tumors

Bleeding Disorders

Important labs

  • CBC
  • PT
  • aPTT

Hemarthrosis มักเกิดจาก:

coagulation factor defect มากกว่า platelet disorder


Hemophilia

Most common musculoskeletal manifestation:

hemarthrosis


Common joints

  • knee
  • elbow
  • ankle
  • hip
  • shoulder

Types of Hemophilic Hemarthrosis

Acute

  • painful
  • swollen
  • warm
  • ROM

Older patients may report:

  • “aura”
  • tingling/warmth before swelling

Subacute

  • synovial hypertrophy
  • fibrosis
  • reduced ROM

Pain may not be prominent


Chronic

hemophilic arthropathy

Features:

  • chronic pain
  • stiffness
  • deformity
  • OA-like symptoms

Pathophysiology of Hemophilic Arthropathy

Blood in joint causes:

  • synovial proliferation
  • cartilage toxicity
  • osteoclast activation
  • recurrent bleeding (“target joints”)

Important:

blood can damage cartilage within ~2 days


Hemophilic Arthropathy Radiographic Stages

Stage

Finding

1

soft tissue swelling

2

osteoporosis

3

osseous deformity

4

cartilage destruction

5

joint disorganization

MRI sensitive กว่า X-ray มาก


Osteoarthritis-related Hemarthrosis

Rare

Usually diagnosis of exclusion

Associated with:

  • degenerative meniscal tear
  • chondrocalcinosis

Septic Arthritis

Rarely causes hemarthrosis

Always exclude if:

  • fever
  • systemic symptoms
  • inflammatory synovial fluid

Vascular Causes

  • aneurysm
  • pseudoaneurysm
  • vitamin C deficiency

May require:

  • surgery
  • embolization

Tumor-associated Hemarthrosis

Important benign tumors:

Synovial hemangioma

  • recurrent painful monoarthritis
  • usually knee
  • MRI best diagnostic tool

TGCT/PVNS

(tenosynovial giant cell tumor / pigmented villonodular synovitis)

Features:

  • recurrent hemarthrosis
  • chronic swollen joint
  • locking/catching
  • dark brown aspirate

MRI:

  • hemosiderin dark on T1/T2

Treatment:

  • synovectomy

Clinical Manifestations

Depends on acuity

Common findings:

  • pain
  • swelling
  • warmth
  • stiffness
  • ROM

Synovial Fluid Findings

Appearance

  • red
  • pink
  • brown/rusty

Important clues

True hemarthrosis

  • usually does NOT clot
  • xanthochromia after centrifuge

Traumatic tap

  • blood increases during aspiration
  • straw-colored supernatant
  • usually clots

Diagnosis

Gold standard

Arthrocentesis

Typical findings:

  • uniformly bloody fluid
  • xanthochromia

When aspiration may not be necessary

  • known hemophilia
  • known traumatic intraarticular injury
  • septic arthritis unlikely

Additional synovial studies

ถ้า diagnostic uncertainty:

  • cell count
  • differential
  • Gram stain
  • culture
  • crystal analysis
  • cytology (if malignancy suspected)

Differential Diagnosis

1. Traumatic tap

Key distinction:

  • fresh clotting blood
  • no xanthochromia

2. Septic arthritis

Suggestive features:

  • fever
  • inflammatory synovial fluid
  • positive culture

3. Crystal arthritis

  • gout
  • CPPD

Diagnosed by crystals

CPPD occasionally causes pseudo-hemarthrosis


4. Reactive arthritis

History:

  • antecedent infection

5. Lyme arthritis

  • endemic exposure
  • large knee effusion

Treatment

General Acute Management

Initial

  • immobilization
  • ice
  • compression

Aspiration

Indications:

  • tense effusion
  • pain relief
  • diagnostic uncertainty

Use large-bore needle (eg 18G)


Analgesia

Avoid:

  • nonselective NSAIDs first 48–72 hr

COX-2 selective safer initially


Postacute

NSAIDs may be used after bleeding risk decreases


Important concept

Single episode hemarthrosis:

usually does not require lavage


Trauma-associated Hemarthrosis

  • immobilize
  • orthopedic consultation
  • assess fracture/internal derangement

Hemophilia-associated Hemarthrosis

Requires:

  • factor replacement
  • aggressive treatment to prevent arthropathy

Children especially vulnerable


Anticoagulation-associated Hemarthrosis

Usually managed with:

  • immobilization
  • analgesia

Consider:

  • anticoagulation reversal if severe

Persistent/recurrent bleeding:

search for structural lesion


Postoperative Hemarthrosis

May require:

  • revision surgery
  • embolization

Tumor-associated Hemarthrosis

Treatment:

  • arthroscopic/surgical synovectomy

Prognosis

Depends on cause

Important:

recurrent hemarthrosis in hemophilia chronic disabling arthropathy


High-yield Clinical Pearls

  • Acute knee hemarthrosis after twisting injury ACL tear until proven otherwise
  • Rapid swelling within hours after trauma strongly suggests intraarticular injury
  • Lipohemarthrosis = think intraarticular fracture
  • Minimal trauma + hemarthrosis evaluate coagulopathy
  • True hemarthrosis usually does not clot
  • Xanthochromia supports true hemarthrosis
  • Hemophilic “aura” (tingling/warmth) is classic
  • Recurrent monoarticular bloody effusion think PVNS/TGCT or synovial hemangioma
  • Bloody joint fluid does NOT exclude septic arthritis
  • Repeated hemarthrosis destroys cartilage and leads to chronic arthropathy

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