3. 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
5. Introduction…
Diagnosis
Peripheral blood smear = sickle rbc
Hb electrophoresis = abnormal haemoglobins
Diagnosis of the major genotypes = simple
Differentiation of various subtypes = complex
6. 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
8. 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.
13. Vaso-occlusive crisis
VOC
Affects virtually all patients
Begins in late infancy & recurs throughout life
Can occur in any organ
Particularly common in bone marrow
14. 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
17. Vaso-occlusive crisis…
Dactylitis (hand-foot syndrome)
Described by Danford
Subsequently Xterized by Smith
Under 5yrs (typically 6 – 18months)
Small bones of hands & feet
22. 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
24. 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
28. 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
29. Septic arthritis
Not common
Tends to occur with painful VOC
Aetiology as in OM
Salmonella arthropathy is very rare
33. 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
34. Osteonecrosis…
Plain radiographs
Mottled attenuation of
the epiphysis
Subchondral lucency
Flattening/collapse of
the articular surfaces
Narrow joint space
Articular sclerosis &
osteophyte formation
36. 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
37. Osteopaenia & Osteoporosis
Reduced bone mineral density (BM hyperplasia)
Common in the vertebrae
Vertebral collapse
41. 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 .
42. References
Dgere A, Ndjoko R, Docquier P, Mousny M, Rombouts J. Orthopaedic
complications associated with sickle-cell disease. Acta Orthop. Belg., 2006, 72,
741-747.
Antonio A, Irene R. Bone involvement in sickle cell disease. British J Haemat,
2005; 129:482–490
Michael HH, Gary EF, James SM. Orthopeedic Manifestations of Sickle-Cell
Disease. J Bio Med, 1990; 63:195-207
Louis S. Osteonecrosis and related disorders. Apley’s system of orthopaedics
and fractures, 9th ed; Hodder Arnold, 2010; 6: 103 – 15.
Archampong EQ, Addo AO. Surgical aspects of the hemoglobinopathies.
Principles and practice of surgery including pathology in the tropics, 4th ed;
51: 1015 – 25.
Geraldo B, Elizabeth D, Francisco A. Osteoarticular involvement in sickle cell
disease. Review article. Rev Bras Hematol Hemoter. 2012;34(2):156-64