OR8.1,OR9.1 | Neuromuscular Orthopaedics — Glossary

A polypropylene or metal-and-leather device fitting the leg, ankle, and foot to hold the ankle at 90 degrees during gait; the standard orthosis for isolated foot drop or equinus in PPRP.

The lower motor neurone cell body in the grey matter of the spinal cord that directly innervates skeletal muscle; its selective destruction by poliovirus produces flaccid paralysis with intact sensation.

A purified bacterial neurotoxin that blocks acetylcholine release at the neuromuscular junction, producing temporary focal chemical denervation and spasticity reduction for 3–6 months; the first-line pharmacological treatment for dynamic deformity in ambulatory CP.

A foot deformity in which the patient bears weight only on the heel due to isolated paralysis of the gastrosoleus with intact dorsiflexors; characterised by absent push-off and a distinctive calcaneal gait.

A group of permanent non-progressive disorders of movement and posture resulting from a lesion or anomaly occurring in the immature brain; the brain lesion is static but the musculoskeletal consequences are progressive throughout skeletal growth.

The process by which surviving intact motor neurones sprout new axonal branches to adopt denervated muscle fibres into enlarged motor units; the mechanism of partial voluntary motor recovery during the convalescent phase of poliomyelitis.

An increased neck-shaft angle of the femur (>135° in adults); common in CP due to spastic adductor and flexor pull on the proximal femur combined with lack of normal weight-bearing stress; predisposes to hip subluxation and dislocation.

A gait pattern in CP characterised by increased hip flexion, knee flexion, and ankle dorsiflexion (calcaneus) during stance; often caused by over-lengthened Achilles tendons, hamstring spasticity, or hip flexor tightness; energy-inefficient and progressive.

A joint deformity that is present during activity (gait, standing) but corrects passively to neutral at rest; caused by spasticity alone without structural contracture; responds to spasticity management (botulinum toxin, orthotics).

A combined foot deformity with equinus (plantarflexion) and inversion of the heel; in PPRP, caused by paralysis of dorsiflexors and peronei with intact tibialis posterior and gastrosoleus.

A foot deformity in which the ankle is held in plantarflexion (toes pointing down), typically resulting from paralysis of dorsiflexors with intact gastrosoleus; the patient walks on the toes.

Increased forward twist of the femoral neck relative to the femoral shaft (normally ~10–15° in adults); exaggerated in CP due to lack of normal bony remodelling stimulation, producing internal rotation gait; corrected by femoral derotation osteotomy.

A deformity that cannot be corrected passively; results from structural shortening of the musculotendinous unit due to prolonged spasticity causing the muscle to grow shorter than the bone; requires surgical lengthening or bony correction.

Paralysis characterised by absent tone, wasting, absent deep tendon reflexes, and absent Babinski response; the hallmark of a lower motor neurone lesion, as seen in PPRP.

Hyperextension of the knee joint during stance, typically a compensatory mechanism for quadriceps weakness in PPRP; structural recurvatum develops over time as the posterior capsule and cruciate ligaments stretch.

A validated 5-level ordinal scale classifying real-world gross motor function in children with CP: level I (walks without restriction) to level V (transported in wheelchair, very limited self-mobility); the strongest single predictor of functional prognosis.

Brain injury from combined hypoxia and ischaemia during the perinatal period, typically following acute obstetric events (cord prolapse, shoulder dystocia, abruption) in term infants; produces spastic quadriplegia or dyskinetic CP depending on the distribution of injury.

A system in which baclofen (a GABA-B agonist muscle relaxant) is delivered directly into the cerebrospinal fluid via a surgically implanted pump, producing profound spasticity reduction with less systemic sedation than oral baclofen; reserved for severe spastic or mixed CP (GMFCS IV–V).

Brain damage from severe neonatal hyperbilirubinaemia, in which unconjugated bilirubin deposits in the basal ganglia and brainstem nuclei; classically causes dyskinetic (athetoid) CP characterised by athetosis, deafness, upward gaze palsy, and dental enamel hypoplasia.

A long-leg orthosis extending from the thigh to the foot, providing stability to both the knee and ankle; prescribed when both quadriceps and ankle-control muscles are paralysed.

Inequality in limb length between the two sides; in PPRP, results from reduced mechanical loading and trophic effects on the affected limb; managed with shoe-raise, contralateral epiphysiodesis, or limb lengthening depending on magnitude and skeletal age.

A 6-point ordinal scale (0 to 4) for grading muscle spasticity based on resistance to passive joint movement; 0 = no increase in tone, 4 = rigid in flexion or extension; the standard clinical tool for documenting spasticity in CP.

The Medical Research Council scale (0–5) for grading voluntary muscle power: 0 = no contraction, 1 = flicker, 2 = movement with gravity eliminated, 3 = movement against gravity, 4 = movement against resistance, 5 = normal power; a grade ≥4 is the minimum donor requirement for tendon transfer.

The condition in which the agonist of a joint is paralysed while the antagonist retains power, producing a progressive unopposed deformity towards the stronger side; the fundamental pathomechanism of PPRP deformities.

A spinal curvature resulting from asymmetric paralysis of trunk muscles; unlike idiopathic scoliosis, it has a defined muscle-paralysis aetiology and is often more severe and more rapidly progressive.

Ischaemic white matter injury in the periventricular region, the dominant brain pathology in premature infants with CP; preferentially damages the corticospinal fibres supplying the lower limbs, producing spastic diplegia.

An enterovirus with three serotypes that is transmitted via the faecal-oral route; type 1 is the most paralytogenic and responsible for the majority of epidemic outbreaks.

The permanent pattern of asymmetric flaccid muscle paralysis and secondary deformities resulting from irreversible anterior horn cell destruction during acute poliomyelitis.

A late progressive condition occurring 15–40 years after acute paralytic poliomyelitis, characterised by new fatigue, weakness, and pain in previously affected or apparently unaffected muscles; attributed to failure of enlarged motor units formed by collateral re-innervation during the recovery phase.

The percentage of the femoral head that lies lateral to the acetabular margin on a standardised AP pelvis X-ray; values <25% are normal, 25–50% indicate a hip at risk, >50% indicates subluxation, 100% is complete dislocation; the standard tool for CP hip surveillance.

A characteristic gait pattern in spastic CP produced by hip adductor and internal rotator spasticity, causing the legs to cross each other during walking; also involves hip and knee flexion and equinus.

A neurosurgical procedure that permanently reduces lower-limb spasticity by selectively sectioning afferent sensory nerve rootlets that generate excessive stretch reflex activity; indicated for spastic diplegia, GMFCS II–III, age 4–7 years.

A bedside test distinguishing gastrocnemius-only tightness (ankle dorsiflexion limited with knee extended but corrects with knee flexed — gastrocnemius relaxed) from combined gastrosoleus tightness (ankle dorsiflexion remains limited even with knee flexed); guides selection of gastrocnemius-only versus Achilles tendon lengthening.

A surgical philosophy in which all orthopaedic corrections required in an ambulatory CP child are performed in a single anaesthetic episode (typically age 6–10 years), minimising cumulative rehabilitation and school disruption; the modern standard for ambulatory diplegic CP with multiple deformity levels.

A velocity-dependent increase in tonic stretch reflex tone (resistance to passive joint movement increases with the speed of stretch); the dominant motor abnormality in spastic CP, resulting from loss of supraspinal inhibition of the stretch reflex.

A surgical procedure in which a functioning muscle-tendon unit is detached from its original insertion and re-attached at a new site to substitute for the function of a paralysed muscle; requires donor grade ≥4, supple joint, neurological stability, and correct vector.

A long-leg iron with a ring at the ischium that transmits body weight through the ischium rather than through the knee or ankle joint; used in resource-limited district hospitals for flail or unstable hip in PPRP.

A tendon transfer in which the tibialis posterior tendon is re-routed through the interosseous membrane of the leg and attached to the dorsum of the foot, converting a plantarflexor-invertor into a dorsiflexor; the standard procedure for equinus foot in PPRP when tibialis posterior is grade ≥4.

A gait pattern in which the trunk lurches over the affected side during single-leg stance, resulting from weakness of the hip abductors (gluteus medius and minimus); a sign of paralytic hip abductor insufficiency in PPRP.

Surgical fusion of the talocalcaneal, talonavicular, and calcaneocuboid joints, performed to correct rigid hindfoot deformity (equinovarus or equinovalgus) and achieve a stable, plantigrade foot; requires skeletal maturity (typically 12–14 years).

A proximal femoral osteotomy that simultaneously reduces coxa valga (varus correction) and corrects femoral anteversion (derotation); the standard bony procedure for hip subluxation/dislocation in CP, usually combined with acetabular reconstruction.