1. Failure of formation of parts
2. Failure of differentiation of parts
3. Duplication
4. Overgrowth (gigantism)
5. Undergrowth (hypoplasia)
6. Congenital constriction band syndrome: part of body properly formed and differentiated, no under/ overgrowth. During embryological stage: something ties around long limb

7. Generalised skeletal developmental defects

1. Transverse
2. Longitudinal -> Preaxial (radius/ tibia), Postaxial (ulna/ fibula)
3. Terminal: segment lost at terminal/ distal part of limb (eg. Terminal transverse failure of formation) [no unaffected parts distal to and in line with deficient portion]
4. Intercalcary: middle part of long limb missing

• Tibia present, femur absent/ hypoplastic
• Knee is at level of groin
• Intercalcary transverse absence

• Preaxial deficiency
• Simple hypoplasia (thumb and radius small) to complete absence (thumb and radius absent)
• Radius absent - ulna continues to grow, arm deviates to radial side (because no opposing growth on radial side) -> results in radial club hand (thumb usually involved as well)
• X-ray hand: 4 metacarpals, thumb absent
• = Radial longitudinal absence

Eg. Congenital Radioulnar Synostosis

• Failure of separation
• Radius stuck to ulna
• Loss of pronation + supination
• Arm remains in pronated/ supinated/ mid-way position
• Fixed in pronation: cannot use shoulder to compensate
• Fixed in supination: can compensate with movt of other jts

• Extra toe/ thumb/ digit

• Long middle finger

• Radial club hand

• Autoamputation
• Due to amniotic constriction band?

• Spinal deformity
• Cutaneous nodules

= Neurofibromatosis

• Tall, shin, decreased AP diameter (flat)
• Long digits
• Arm span longer than body height

= Marfans syndrome

• Gross limb deformities
• Broken many bones
• Blue sclera
• Repeated fracture and repair

= Osteogenesis imperfecta

DIAG: Colles fracture

• Fracture of distal radius, turned radially, shortening, radial deviation

DIAG: Burns

• Burns: contraction of ST
• Surgical harvesting of skin for burns (clear margins)
• Traumatic cause

DIAG: Infection (eg. TB) -> acute kyphosis

• Shortened trunk relative to legs
• Less seen in HK (seen in Northern China)

DIAG: syphilis

• 50 yo retired sailor
• Severely deformed knee, no pain
• Back: break but no pain
• Infection -> neurological deficit -> limb deformity

DIAG: degeneration of spine

• Loss of lordosis

DIAG: RA

• Hands
• Ulnar deviation
• Subluxed joints
• Inflammatory disease

DIAG: RA

• Halus valgus

DIAG: AS

• Hunchback, cannot straighten

DIAG: fibrous dysplasia

• Femur: crooked, not uniform BMD (ground-glass appearance)
• Not acute trauma: otherwise would see 2 sections of one at acute angle
• Therefore, chronic (pathological) - benign bone lesion

DIAG: scoliosis

• Idiopathic
• Children + adolescent girls
• Evidence that related to chromosomal abnormalities

Neuromuscular

1. Cerebral palsy: insult to immature brain in prenatal period
2. Poliomyelitis: virus affecting anterior horn cells; rarely see new cases now
3. Muscular dystrophy: hereditary, affects muscle
4. Spina bifida: neurological, abnormality during formation of lumbar spine (failure of closure of spine)
5. Peripheral nerve injuries:

• Fixed
• Non-progressive brain lesion

• Prenatal
• At birth
• Post-natal

• Poor peripheral control of m's
• Weakness of antagonist -> contractures
• Previously, pre-term babies (200g) died of natural causes, but now kept alive, therefore see more of these conditions now

• Poliovirus
• Anterior horn cells
• Motor nuclei of brain stem
• No spasticity
• Wasting of muscles
• Muscles that are active at time of disease contraction are those most affected - eg. Respiratory, anti-gravity muscles (gastrocsoleus, quads, hip extensors) - therefore bend over at hips, knee bent, ankle dorsiflexed
• Need braces to support weakened joints

DIAG: Claw hand

• Ulnar n lesion
• Wasting of intrinsic muscles of hand (lumbricals)
• Wasting of digit minimi of hypothenar muscles
• Eg. of peripheral nerve causing imbalance of m's leading to deformity

3 + 4: main 2 treatment methods

1. Growth: bad in hemivertebra
2. Gravity: most significant aggravating factors of deformities
3. Muscular imbalance

1. Promote growth on side growing slower
2. Retard growth on side growing faster
3. Combination of 1 + 2

DIAG: Hemivertebra

• Stop growth on faster growing side
• Enhance growth on slower growing
• Need to time correctly - otherwise inverse deformity
• Fused part of spine on convex side
• Concave side: promote growth

1. Migrate to the moon???
2. Bracing: support part of body being deformed by gravity, for how long?
3. Fusion: block movt of jt, keep in good position, fuse (bring segments together into one block)

DIAG: idiopathic scoliosis

• Increased deformity during growth period
• Therefore, wear brace to wear from age 11-14 (or until growth ceases)

DIAG: polio

• Poor control of trunk muscles - cannot sit straight (needs to use hand to support)
• Brace will constrict her breathing (which is already weak due to polio)
• Therefore fuse spine: stiff, but straight
• Compromise: crooked mobile spine or stiff straight spine

Balance m's by

1. Muscle transfer: take m from useful side to replace paralysed m. If no quads but have hams, transfer hams to quads and attach to patellar. If done early, brain can learn new task (higher-centre training). If done later, difficult to learn. Need to find m that is close to original function. Need to make sure that site to be moved can be spared (eg. 2 extensor tendons going to index finger: extensor indicis (extends index finger alone - therefore, can use for, for example, extension of thumb) + extensor digitorum communis (cannot use)
2. Arthrodesis: block jt, don't need tendon, stabilise jt

1. Osteotomy: bone deformity; break and realign bone in new position
2. Lengthening: most people want longer limbs rather than shorter!
3. Shortening
4. Reduction
5. Augmentation
6. Combination

DIAG: AS

• Osteotomy of spine
• Crush L3 vertebral body and take wedge of lumbar spine out, internal fixation

DIAG: Hemivertebra

• Completely remove hemivertebra
• Hemivertra will worsen as Pt ages

DIAG: mal-united fracture

• Osteotomy and external fixation

DIAG: shortening of R leg

• Pelvic tilting, tip-toed
• Break bone, callus formation then distract ends (callotaxis)
• Once have bone formation, remove external fixator