discuss the orthopaedic manifestations of sickle cell disease

Discuss the Orthopaedic Manifestations of SCD &

their ManagementDr. Arojuraye S.A

National Orthopaedic HospitalDala-Kano

Outline

Introduction Pathophysiology Orthopaedic manifestations Management Conclusion

Introduction

SCD = Inherited disorder due to HbS Substitution of valine for glutamic acid at 6th a.a of the

ß globin chain Inheritance = autosomal recessive Major genotypes = SS, SC & sickle-beta thalassemia HbS is poorly soluble It assumes sickle shape when deoxygenated

Introduction…

Incidence Black American

AS = 8 – 10% SS = 0.2 - 0.5%

West African AS = 20%

Introduction…

Diagnosis Peripheral blood smear = sickle rbc Hb electrophoresis = abnormal haemoglobins Diagnosis of the major genotypes = simple Differentiation of various subtypes = complex

Introduction… 1910: First description of SCD was made in Chicago

by Herrick.

1927: Hahn & Gillespie showed that sickling of the rbc was induced by deoxygenation & reversed with reoxygenation.

1949: Electrophoretic abnormalities of Hb were demonstrated by Pauling et al

Pathophysiology

Hypoxia & dehydration Sickling Membrane distortion Rbc stickiness

Haemolysis & Vaso-occlusion

Pathophysiology…

Haemolysis results from destruction of the sickled rbc by monocytes & macrophages.

Vaso-occlusion is due to

entrapment of sickled cells in the microcirculation = ischaemia.

Pathophysiology…

Clinical manifestations

CNS: CVA, meningitis

Ocular: Retinopathy

Pulmonary: Acute chest syndrome, pneumonia, restrictive lung disease

Clinical manifestations… Renal: Haematuria, nephropathy

Spleen: Massive splenomegaly, autosplenectomy

Biliary: Cholelithiasis, cholecystitis

CVS: HF, MI, cor pulmonale

Orthopaedic manifestations

Acute Vaso-occlusive crisis Osteomyelitis Septic arthritis Stress fracture Vertebral collapse

Chronic Osteonecrosis Chronic arthritis Chronic osteomyelitis Osteoporosis Impaired growth

Vaso-occlusive crisisVOC Affects virtually all patients Begins in late infancy & recurs throughout life Can occur in any organ Particularly common in bone marrow

Vaso-occlusive crisis…

Clinical presentation Intense pain Localized tenderness Swelling & erythema Febrile episodes Juxta-articlar area = joint effusion Leucocytosis are also common Most patients recover with no complications

Vaso-occlusive crisis…

Plain radiograph Diagnosis is clinical Not useful in acute phase Later: subchondral &

intramedullary lucency & patchy sclerosis

Vaso-occlusive crisis…

MRIRadioisotope scan Very sensitive Not specific (Infarction vs OM) Not routinely used

Vaso-occlusive crisis…

Dactylitis (hand-foot syndrome) Described by Danford Subsequently Xterized by Smith Under 5yrs (typically 6 – 18months) Small bones of hands & feet

Vaso-occlusive crisis…

Dactylitis Clinically; acute, painful swelling Erythema & warmth Most episodes resolve within 2 weeks Epiphyses = premature fusion & shortened fingers

Vaso-occlusive crisis…

Dactylitis Radiological evidence of

new bone (2weeks)

‘Moth-eaten’ appearance bcs of cortical thinning & irregular attenuation of the medullary spaces

Vaso-occlusive crisis…

Dactylitis Histology:

Infarction of the marrow, medullary trabeculae & inner layer of the cortex

Subperiosteal new bone formation

Vaso-occlusive crisis…

Treatment Infection, dehydration, acidosis, hypoxia, cold, IVF & analgesia

Paracetamol NSAIDs Opioid derivatives

Antibiotics

Osteomyelitis 90% of SCD develop OM before 10yrs No bone is exempted Multifocal Precipitated by VOC

Risk factors in SCD Hyposplenism Impaired complement activity Infarcted or necrotic bone

Osteomyelitis

Common organisms Staphylococcus aureus Salmonella (Hodges & Holt, 1951)

Osteomyelitis …

Diagnosis Common mgt dilemma

Failure = life threatening infection Erroneous diagnosis = unnecessary 6wks of antibiotics

Pain, swelling, tenderness & pseudoparalysis Most common sites: Femur, tibia & humerus Often affect diaphysis Features are similar to those of VOC

Osteomyelitis …

Plain radiograph Always first step Not diagnostic May exclude other dxs Bony changes in 2-3wks

Osteomyelitis …

USS Soft tissue disturbance Subperiosteal collection Useful for aspiration

Osteomyelitis …

Bone scan MRI

Osteomyelitis …Treatment Based on organism 3rd generation cephalosporin Ciprofloxacin in older children Drainage Bone drilling

Once AO COM Conservative Rx, until involucrum is formed Sequestrectomy

Septic arthritis

Not common Tends to occur with painful VOC Aetiology as in OM Salmonella arthropathy is very rare

Septic arthritis…

Rx Early aggressive drainage, debridement & splintage A two-week course of IV antibiotic

Osteonecrosis

AVN Most common complication More common in SC > 50% of SCD > 30yrs M:F = 1

Osteonecrosis…

Presentation There may be hx of trauma Pain, limited motion Occasionally with pain at rest May be asymptomatic (shoulder)

Osteonecrosis…

Common sites Femoral heads Head of the humerus Knee joint Small joints of the hands & feet Common to have multiple joints affected Hip: bilateral in >50% Shoulder : 74% have AVN of HOF

Osteonecrosis…

Plain radiographs Mottled attenuation of

the epiphysis Subchondral lucency Flattening/collapse of

the articular surfaces Narrow joint space Articular sclerosis &

osteophyte formation

Osteonecrosis…

MRI Best for early disease Double line sign

Osteonecrosis…

Untreated, 87% of HOF will collapse within 5 years Bed rest & symptomatic Rx: unacceptable Early dx: Core decompression & osteotomy Late dx: Arthroplasty

SCD patients must be cared for in specialized centres with expertise in SCD as they have a very high

incidence of perioperative complications

Osteopaenia & Osteoporosis

Reduced bone mineral density (BM hyperplasia) Common in the vertebrae Vertebral collapse

Osteopaenia & Osteoporosis…

Radiograph Increased radiolucency Prominence of vertebral trabeculae Smooth, biconcave vertebrae ‘Fish-mouth’ vertebrae

Growth disturbance

BM hyperplasia Vertebrae

Ischaemia of the vertebral growth plate

Disturbance of vertebral growth

Characteristic ‘H’ shaped vertebrae

Some develop ‘tower’ vertebra

Growth disturbance…

Long bones Premature closure of

epiphyses Impaired growth of the

long bones

Conclusion SCD prognosis is still poor Orthopaedic manifestations: major cause of morbidity Mgt of its orthopaedic complications is challenging Necrosis & infections are responsible for major

functional impairment Surgery is the mainstay of Rx of these complications While waiting for new genetic therapy for SCD, the

surgeon will treat the complications but should keep in mind that anaesthesia is more risky for these

patients .

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Louis S. Osteonecrosis and related disorders. Apley’s system of orthopaedics and fractures, 9th ed; Hodder Arnold, 2010; 6: 103 – 15.

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