5 Deformities and congenital disorders
Deformities may be congenital or acquired, and they may reflect an underlying abnormality of bone, joint, or soft tissue.
CONGENITAL DEFORMITIES
Congenital deformities or malformations, by definition, are attributable to faulty development and are present at birth, though they may not be recognised until later. They vary from severe malformations that are incompatible with life and may be found in still-born infants, to minor abnormalities of structure that have no practical significance. Incidence varies in different countries and among different races: in Britain probably 2 or 3% of infants are born with some significant developmental abnormality, but only about half of these affect the musculo-skeletal system. Some of the better-known anomalies are summarised in Table 5.1 (p. 53).
Table 5.1 Some of the better-known congenital deformities or anomalies of orthopaedic interest, with their salient clinical features. (When a fuller description appears elsewhere in this book the relevant page number is given. Conditions not thus designated are either so rare or of such little importance to the student that further description is unnecessary.)
| Name of deformity or anomaly | Clinical or pathological features |
|---|---|
| Generalised | |
| Osteogenesis imperfecta (fragilitas ossium) (p. 62) | Fragile soft bones, easily broken or deformed. Often blue sclerotics. Joint laxity. Otosclerosis |
| Diaphysial aclasis (multiple exostoses) (p. 63) | Cartilage-capped bony outgrowths from metaphyses. Deficient remodelling. Stunted growth |
| Dyschondroplasia (multiple chondromatosis; Ollier’s disease) (p. 65) | Masses of cartilage in metaphyses of long bones. Impaired growth. Deformity. Often unilateral |
| Achondroplasia (chondro-dystrophy) (p. 61) | Short-limb dwarfing from defective growth of long bones. Trident hand. Large head |
| Osteopetrosis (Albers–Schönberg disease; ‘marble bones’) | Hard dense bones, but with increased liability to fracture. Anaemia from obliteration of medulla |
| Gargoylism (Hurler’s syndrome) | Dwarfing. Kyphosis from deformed vertebrae. Corneal opacity. Large liver and spleen. Mental deficiency |
| Cranio-cleido dysostosis (p. 71) | Impaired ossification of skull. Deficient clavicles. Often deficient symphysis pubis |
| Arthrogryposis multiplex congenita (amyoplasia congenita) | Stiff deformed limb joints from defective development of muscles, usually secondary to nerve cell deficiency though a type due to primary dysplasia of muscle is also recognised. Hips often dislocated. Club feet |
| Pseudohypertrophic muscular dystrophy | Genetic transmission to boys through female carriers. Progressive muscle weakness evident at age 3–6 years. Raised urinary creatine phosphokinase: carriers may thus be identified. The defect may be diagnosed in early pregnancy, when abortion may be advised |
| Fibrodysplasia ossificans progressiva (p. 71) | Ectopic ossification, often beginning in trunk but extending to limbs. Short great toe |
| Familial hypophosphataemia (p. 76) | Rachitic bone changes corrected only by massive doses of vitamin D. Hypophosphataemia not responsive to vitamin D |
| Cystinosis (renal tubular rickets) (p. 78) | Rachitic rarefied bones with consequent deformity. Hypophosphataemia. Glycosuria; amino-aciduria |
| Neurofibromatosis (von Recklinghausen’s disease) (p. 70) | Café au lait areas or spots. Cutaneous fibromata. Neurofibromata on cranial or peripheral nerves. Often scoliosis. Occasionally, overgrowth of bone |
| Haemophilia (p. 145) | Prolonged blood clotting time from deficiency of Factor VIII. Bleeding into joints or soft tissue |
| Gaucher’s disease (p. 72) | Deposition of kerasin in reticulum cells, causing cyst-like appearance in bones, and large liver and spleen |
| Down’s syndrome (mongolism) | Mental and physical impairment from trisomy of chromosome 21, giving 47 instead of 46 chromosomes |
| Trunk and spine | |
| Congenital short neck (Klippel–Feil syndrome) (p. 188) | Short stiff neck with low hair-line. Fused or deformed cervical vertebrae |
| Congenital high scapula (Sprengel’s shoulder) (p. 189) | Scapula tethered high up, usually only on one side. Scapular movement impaired |
| Cervical rib (p. 202) | Often symptomless. Vascular symptoms (partial ischaemia) or nerve symptoms (paraesthesiae, lower trunk paresis) |
| Hemivertebra (congenital scoliosis) (pp. 213, 218) | Defective development of vertebra (and often of adjacent structures) on one side. Scoliosis |
| Spina bifida (spinal dysraphism) (p. 171) | Spina bifida occulta, meningocele or myelocele. Often leg deformities from paralysis or muscle imbalance. Often incontinence. Often associated hydrocephalus. Diagnosable in early pregnancy from excess of alpha-fetoprotein in urine and amniotic fluid |
| Limbs | |
| Congenital arterio-venous fistula | Hypertrophy and lengthening of limb. Bruit |
| Congenital amputation | Part or whole of one or more limbs absent |
| Phocomelia | Aplasia of proximal part of limb, the distal part being present (‘seal-limb’). Diagnosable in pregnancy by ultrasonography |
| Constriction rings | Limb or digit constricted as if by a tight string. May be associated with syndactyly |
| Absence of radius (radial club hand) | Hand deviated laterally from lack of normal support by radius. Thumb often absent |
| Absence of thumb | Thumb alone may be absent, but other deformities may co-exist |
| Absence of proximal arm muscles | Trapezius, deltoid, sternomastoid, or pectoralis major absent |
| Radio-ulnar synostosis | Forearm bones fused at proximal ends, preventing rotation |
| Madelung’s deformity (dyschondrosteosis) (p. 303) | Head of ulna dislocated dorsally from lower end of radius. Radius bowed |
| Syndactyly | Webbing of two or more digits |
| Polydactyly | More than five digits |
| Ectrodactyly | Lobster-claw appearance of hand, with pincer grip |
| Congenital dislocation of hip (p. 343) | Neonatal: diagnostic click obtainable. Later infancy: shortening; limited abduction. Radiographs diagnostic |
| Congenital coxa vara (p. 376) | |
