# Congenital Limb Deficiencies

> Congenital limb deficiencies for NEET-PG Orthopaedics: fibular and tibial hemimelia, PFFD, Aitken and Achterman-Kalamchi grades and amputation choice.

- Canonical URL: https://prepelephant.com/topics/neet-pg/orthopaedics/congenital-limb-deficiencies
- Exam / course: NEET-PG · Subject: Orthopaedics
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Maheshwari's Essential Orthopaedics; Campbell's Operative Orthopaedics
- How to cite: "Congenital Limb Deficiencies", PrepElephant, https://prepelephant.com/topics/neet-pg/orthopaedics/congenital-limb-deficiencies

## Direct answer

Congenital limb deficiencies are absent or hypoplastic segments of a limb present at birth, classified as longitudinal or transverse. Fibular hemimelia, tibial hemimelia and proximal femoral focal deficiency are the longitudinal deficiencies most often tested. Management depends on the type and functional prognosis, ranging from prosthetic fitting and limb lengthening to amputation with a prosthesis.

## What you must remember

- **Longitudinal versus transverse:** a longitudinal deficiency lacks a bone along the axis of the limb, whereas a transverse deficiency lacks segments across it.
- **Fibular hemimelia:** among the commonest longitudinal deficiencies, with a short limb, knee instability, valgus and absent lateral rays of the foot.
- **Tibial hemimelia:** partial or complete absence of the tibia, with a varus-supinated foot and, when the tibia is wholly absent, an unstable knee; the outlook depends on the type.
- **Proximal femoral focal deficiency (PFFD):** a short femur with hip instability, graded by the Aitken classification (A to D).
- **Achterman-Kalamchi classification:** grades fibular hemimelia (types IA, IB and II) by how much fibula is present; the Paley classification also grades fibular, tibial and femoral deficiencies and the adjacent joints.
- **Functional principle:** the goal is the best function, not the greatest length, so a flail joint may do better with amputation and a prosthesis.
- **Syme amputation:** an ankle-level amputation that preserves the heel pad and allows weight-bearing on the residual limb.
- **Associated anomalies:** cardiac, renal and spinal anomalies are screened for, since limb deficiency can be part of a syndrome.

## Matching the deficiency to a functional plan

A newborn has a short leg with an absent fibula, a valgus knee and a foot missing its outer toes. The reasoning moves from classifying the deficiency to choosing a route that gives the best function.

1. **Classify the pattern:** determine whether the deficiency is longitudinal or transverse and which long bone is absent, using radiographs of both limbs.
2. **Screen the other limb and systems:** check for contralateral involvement and for cardiac, renal and spinal anomalies, which may signal a syndrome.
3. **Assess the adjacent joints:** instability at the knee, hip or ankle decides whether stabilisation must precede any decision about length.
4. **Grade the deficiency:** apply the Achterman-Kalamchi (fibular), Aitken (femoral) or Paley classification to the missing bone and the adjacent joints.
5. **Choose the reconstructive route:** lengthening, realignment or stabilisation is used where function can be improved, while amputation with a prosthesis is preferred where a reconstructed limb would function worse.
6. **Plan prosthetic and developmental care:** early prosthetic fitting supports walking and development in parallel with surgery, and the family is counselled throughout.

## Where the exam tries to catch you

Examiners test whether you judge function rather than length, and whether you remember the syndromic context.

- **Trap:** equating a short limb with a need for lengthening. **Correct:** lengthening is chosen only when the joints are stable and a functional limb is achievable, since a flail, unstable joint often does better with amputation.
- **Trap:** missing a syndromic association. **Correct:** cardiac, renal and spinal anomalies should be checked, because a limb deficiency can be part of a syndrome.
- **Trap:** treating the deficiency as a purely orthopaedic problem. **Correct:** development, prosthetic fitting and family counselling are equally part of the plan.

## Frequently asked questions

### What is fibular hemimelia?

Fibular hemimelia is a congenital absence or hypoplasia of the fibula, causing a short leg, knee instability and valgus, along with loss of the lateral rays of the foot. It is one of the commonest longitudinal deficiencies of the limb.

### What is the Achterman-Kalamchi classification used for?

The Achterman-Kalamchi classification grades fibular hemimelia by how much of the fibula is present. Proximal femoral focal deficiency is graded instead by the Aitken classification, and both help guide whether limb reconstruction or amputation is preferable.

### When is amputation preferred to reconstruction in limb deficiency?

Amputation with prosthetic fitting is preferred when reconstruction would leave an unstable or poorly functioning limb, particularly at the ankle or in tibial hemimelia. The aim is the best functional outcome, not the greatest limb length.

### Why are cardiac and renal anomalies screened for in limb deficiency?

Limb deficiencies can occur as part of multisystem syndromes, and cardiac, renal and spinal anomalies are recognised associations. Screening at diagnosis identifies problems that change management and prognosis.