Paediatric Amputee & Congenital Limb Deficiency Management

Children are not small adults. Paediatric amputee care differs fundamentally from adult practice. The growing skeleton and its open physes drive length and growth, children adapt remarkably, and their stumps behave differently, so adult amputation principles do not simply transfer. The general rule is to preserve length, growth plates and joints, and the two consequences that dominate surgery, the preference for disarticulation and terminal bony overgrowth, are taken together under Surgical Principles.

Why children adapt. The explanation lies in the plasticity of the developing brain and how the cortical body schema forms. A child integrates a prosthesis into the body schema, and learns one-handed and compensatory strategies, much more readily than an adult. That is the rationale for early, milestone-timed prosthetic introduction: it exploits the developmental window. Adaptation is not the same as prosthetic acceptance, and the upper limb shows the difference (see the Management section).

Phantom sensation in the congenital limb. In congenital deficiency the missing limb was never represented in the cortical body schema, so phantom sensation is usually absent or minimal.

Phantom sensation after amputation. The common assumption is that a phantom can occur after an acquired amputation but is generally less frequent and less troublesome than in adults, tends to diminish with growth, and that severe phantom pain is uncommon, so management is mainly reassurance and symptomatic. The only paediatric prevalence dataset does not support that. Krane and Heller found phantom sensation in 100% of each group, including children amputated for a congenital deformity, and phantom pain in the overwhelming majority, which at the time of the study had resolved in only 35%.

• Krane's congenital group were children amputated for a congenital deformity, not children born without the limb
• Screen for phantom pain and treat it rather than reassuring by default
• Formal neuroma strategies such as TMR and RPNI are a separate topic

Congenital: look beyond the limb. Congenital limb deficiencies are uncommon birth defects that may go undetected on prenatal ultrasound until birth. A child with a congenital limb difference should have a diagnostic evaluation to rule out syndromes involving other organ systems or known associations, because the limb may be one feature of a wider condition.

Acquired: preserve growth. Trauma is the commonest cause of acquired paediatric amputation. Tumour, where limb salvage is weighed against amputation or rotationplasty, and infection or sepsis, such as meningococcal purpura fulminans, account for others. The same paediatric principles apply: preserve length, growth plates and joints, and favour disarticulation. In both groups the prosthetic pathway is planned with the family.

Use the ISO/ISPO terminology, not the classical names. Congenital limb deficiencies are described as transverse or longitudinal. A transverse deficiency is an amputation-like absence of everything distal to a level, with the limb developed normally down to that point; the commonest is a transverse forearm deficiency. A longitudinal deficiency is absence of a specific bone or ray along the limb axis, with structures distal to it often partly present; fibular, tibial and femoral deficiencies are the examples that reach the orthopaedic clinic.

Why the old names went. Amelia, hemimelia and phocomelia are imprecise about exactly what is missing and are largely abandoned in formal description, though they persist in conversation and in older literature. Saying "longitudinal fibular deficiency" rather than "fibular hemimelia" signals current practice, and more importantly forces the description to specify which bone and how much of it.

The amputation-versus-reconstruction decisions live in the individual conditions. Each turns on different anatomy: whether a plantigrade foot can be preserved, how much length will ultimately be missing, whether the knee is stable, whether there is a quadriceps mechanism.

• Fibular Hemimelia - the commonest longitudinal deficiency, and the classic choice between Syme or Boyd amputation and staged reconstruction with lengthening. Boyd retains the calcaneus and its heel pad, which resists the pad migration that can trouble a Syme.
• Tibial Hemimelia - where the presence or absence of a functioning quadriceps and proximal tibia dominates the decision.
• Proximal Femoral Focal Deficiency and Rotationplasty - where the ankle can be turned to serve as a knee.
• Congenital Lower Limb Deficiency Overview for the shared framework, and Limb Lengthening Principles and Limb-Length Discrepancy and Epiphysiodesis for the reconstruction side of the same conversation.
• Lower Limb Amputation Levels and Foot and Ankle Amputation Levels for the levels themselves.

Disarticulate when you can. Where feasible, a disarticulation (through a joint) is preferred over a transosseous (through-bone) amputation in the growing child. It keeps the distal physis, so the residual limb grows with the child and length is maximised. It gives a robust, end-bearing stump, and because there is no cut bone end it does not develop terminal bony overgrowth.

Terminal bony overgrowth. This is the commonest complication of a paediatric transosseous stump. New bone forms at the cut end, most often in the humerus, then the fibula, tibia and femur, creating a sharp spike that tents or penetrates the skin and causes pain and bursae. It typically needs surgical revision, often more than once during growth, and families should be counselled to expect this.

Why it recurs. The overgrowth is appositional new bone at the cut diaphyseal end (oblique terminal, periosteal new-bone formation) and is not driven by the proximal growth plate. It therefore arises at the transected end of a long bone and keeps recurring through growth even when the distal physis has been removed, which is precisely why a disarticulation, with no cut end, does not overgrow.

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Capping, not just resection. Simple stump resection alone has a high recurrence. The durable solution is to cap the cut end, classically with an autologous osteochondral cap (the Marquardt technique, using a cartilage-bearing autograft such as resected epiphysis or iliac apophysis) or with a synthetic cap. The cap resurfaces the bone end and markedly reduces recurrence.

The team. Care is multidisciplinary and family-centred, drawing on orthopaedics, rehabilitation (physiatry), the prosthetist, physiotherapy and psychology, and built around the child's and the family's goals. A multidisciplinary approach with the child and family can lead to a successful, functional and fulfilling life.

Ongoing care. Beyond fitting the prosthesis, the plan includes:

• Psychosocial support, and periodic review through growth
• Revision and capping of terminal overgrowth when the spike causes pain or skin problems
• Revisiting the reconstruction-versus-prosthetic decision as the child develops

Timing to developmental milestones. This means specific milestones at specific ages. A prosthesis is introduced when the child is developmentally ready to use it for the task it exists to perform. Fitted earlier it is a burden the child discards; fitted later it is an intrusion into a body schema that has already been built without it.