Congenital lower limb deficiencies are present at birth and characterized as longitudinal or transverse and complete or incomplete. They can involve 1 or more bones, occur unilaterally or bilaterally, and are seldom associated with organ system defects. Some children may have involvement of upper and lower limbs.
Medications known to affect limb development include thalidomide, retinoic acid, and misoprostol. Teratogenic causes are often difficult to study because prenatal history may be complicated by maternal recall bias.1 Limb deficiencies can also be caused by vascular disruption (e.g., amniotic band syndrome), vascular malformations (e.g., Poland syndrome), or genetic factors (spontaneous point mutation). In most cases the cause is unknown.2 Of the more than 120 clinical congenital limb deficiencies described in the Online Mendelian Inheritance in Man (OMIM; www.ncbi.nlm.nih.gov/omim), less than 40% have a known molecular basis.3 Maternal cigarette smoking increases the risk for longitudinal deficiencies, such as preaxial deficiencies of the lower extremity.4 Poorly controlled maternal diabetes during the first trimester can cause longitudinal deficiencies as well as sacral agenesis with lower extremity hypoplasia.5 In addition, an association between maternal thrombophilia and congenital limb deficiencies has been described.6
Epidemiology including risk factors and primary prevention
Overall, congenital limb deficiencies occur at a rate of 0.26 to 1 per 1000 live births.3 The lower limb is involved in less than half of these cases, and among those, the most common deficiencies are longitudinal toe reductions (14.2%), longitudinal femoral deficiencies (6.1%), longitudinal fibular deficiencies (1.9%), and longitudinal tibial deficiencies (1.7%). The Center for Disease Control and Prevention estimates that each year 750 infants are born in the United States with lower limb deficiencies.7 No racial predilection has been noted.8 Some data points toward a relation between paternal occupation and increased prevalence of birth defects, including limb deficiencies, in the offspring of artists.9 Primary prevention includes a prenatal daily multivitamin with folic acid (400 µg), screening for smoking, diabetes, and thrombophilia, as well as stopping teratogenic medications prior to pregnancy.
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
Lower limb congenital malformations may progress with growth, depending on the extent and number of bones and growth plates involved. For example, in children with longitudinal fibular deficiency, the lateral femoral growth plate is often affected, causing progressive genu valgum.
Specific secondary or associated conditions and complications
Most lower limb deficiencies are not associated with other organ system defects. Some exceptions include the following:
- Tibial deficiency has been reported with deafness, ectrodactyly or polydactyly of the hands, and craniofacial abnormalities.
- Femoral hypoplasia-unusual facies syndrome involves bilateral femurs, facial abnormalities, including micrognathia and cleft palate, hypoplasia or synostosis of the upper extremity, vertebral abnormalities, congenital heart disease, and polydactyly.
- Roberts-SC phocomelia syndrome comprises bilateral symmetric tetraphocomelia and may include thumb aplasia, syndactyly, elbow and knee flexion contractures, mental retardation, cleft lip/palate, micrognathia, hypotelorism, cryptorchidism, and cardiac defects.
- Sacral agenesis can cause hemipelvectomy, or hip disarticulation, and is often associated with neurogenic bowel and bladder.1,12,13
2. ESSENTIALS OF ASSESSMENT
- A careful birth history, including prenatal exposure.
- Family history, while rarely positive, may help the clinician determine possible genetic links.
- Developmental history, including gross and fine motor milestones.
- Full review of systems to rule out possible syndromes, in particular, cardiac, musculoskeletal, eyes/ears/nose/throat, neurologic, gastrointestinal, and genitourinary.
- Assessment of family perceptions, expectations, and goals.
- Skin should be examined for dimples, puckering/tethering, verrucous hyperplasia, breakdown, or other abnormalities. Check for lymphedema in any of the extremities.
- Joint assessment to determine stability and weight-bearing potential is important. Measure active and passive range of motion. Specifically, hip or knee dislocation and ankle stability are very important factors in surgical planning. Voluntary movement of the joint is also helpful in determining the child’s ability to use it in combination with a prosthesis or orthosis in the future. In the older child, perform quantitative strength testing. Â· Examine the spine for scoliosis or overlying skin abnormalities.
- Observe if the child has adequate seated/standing balance.
- In the infant or toddler, evaluate how mobility is achieved, for example commando, bear, or reciprocal crawling. Note if the child attempts to pull to stand on objects in the room.
- Observe ambulation, if present.
- Perform sensory testing, if the child is able to cooperate with the exam.
- Complete a full physical exam to rule out major organ abnormalities (e.g., cardiac defects).
Dynamic standing balance and gait or mobility assessment is important for prosthetic planning. Assess how the child interacts with others to determine cognitive status, speech, and development.
If syndromic findings present on exam, consider appropriate genetic testing (may consider genetic consultation).
Radiographs of the involved limb with opposite side comparison can be helpful in determining outcomes and possible surgical planning. Consider spine films if abnormalities are observed on exam. In newborns, radiographs are often not conclusive because of the lack of bony ossification. For diagnostic purposes, newborns may require repeat radiographs in the future.
Supplemental assessment tools
For abnormal gait patterns, if there is difficulty with functional prosthetic fitting, or surgical planning, the examiner may consider formal gait analysis, if available.
Early predictions of outcomes
Presence of knee or ankle function can drastically improve options for surgical conversion and prosthetic fitting. For example, in the case of proximal focal femoral dysplasia, the presence of ankle range of motion/stability with lack of knee function may offer possibilities of rotationplasty surgery. This option offers superior control and function over a mechanical prosthetic knee. It is also important to project limb length discrepancies when developing a treatment plan. The presence or absence of active knee extension in the child with tibial longitudinal deficiency can distinguish if knee disarticulation or foot ablation is a more appropriate surgical plan.12 Assessing stability of the knee is important if guided growth or lengthening is being considered.14
Perform an assessment of home and school environment and accessibility. Home climate (e.g., hot and humid) may also impact decisions regarding the type of prosthesis prescribed.
Social role and social support system
Recommend screening children for psychosocial issues, such as self-image/self-esteem problems or teasing/bullying in school. Assessment of parental cultural and personal beliefs is important because this can impact the child’s support system. Feelings of guilt among parents are common, particularly among mothers. Assess access to resources, such as physical therapy for gait training and funding for prostheses.
The child’s access to appropriate prosthetic follow-up should be carefully assessed prior to surgical intervention, especially in the case of patients who live in very rural areas or less developed parts of the world.
3. REHABILITATION MANAGEMENT AND TREATMENTS
Coordination of care
A multidisciplinary approach is recommended when available.
- Biannual, coordinated assessments by a physician, physical therapist, occupational therapist, when needed (e.g., multilimb involvement), prosthetist, social worker, and psychologist.
- Occupational therapist: evaluates activities of daily living and assists with adaptive fitting (e.g., in the case of upper limb involvement) if the patient uses their feet for activities and needs to be able to remove the prosthesis for foot use.
- Prosthetist: inspects function of the prosthetic components and makes adjustments, as necessary, to ensure adequate fit, in collaboration with the physician.
- Social worker and/or psychologist: often needed to assess the patient and family for psychosocial risk factors, depression, problems with self-image/self-esteem, acceptance of disability, bullying, or other school issues.
- Multidisciplinary management ensures holistic care of a developing, growing child with a limb deficiency.
In community-based practice, physician follow-up should be coordinated with the prosthetist whenever possible.
Patient & family education
Education on proper care of the prosthesis and residual limb is important to avoid injury or morbidity. Children should be encouraged to be active and involved in sports or extracurricular activities. Refer to support groups, medical camps, online communities, and facilitate meeting other families, if indicated.
Useful resources include the following:
- Amputee Coalition of America (www.amputee-coalition.org)
- Amputee-Online.com (www.amputee-online.com)
- Challenged Athletes Foundation (www.challengedathletes.org)
- Disabled Sports USA (www.dsusa.org)
- Limbless Association (www.limbless-association.org)
- Limbs for Life Foundation (www.limbsforlife.org)
- U.S. Paralympics (www.usparalympics.org)
Amputee activity levels have historically been classified by the Medicare Functional Classification Level, or K level. The K level is a subjective assessment of current activity level of the amputee based on self-report and clinical observation. Children are often automatically put in the K4 level (potential for ambulation that exceeds basic ambulation skills, i.e., high impact/energy); it is not a useful qualitative measure of treatment outcome.
Another measurement of community-based gait performance in children is the data collected by an ankle-worn accelerometer, worn over a specific time period.15 However, this has not been applied in pediatric amputees. Subjective measures of prosthetic use/fit can include extracurricular activity, pain assessments, and skin evaluation. Questionnaires, such as the Prosthetic Profile of the Amputee and Prosthesis Evaluation Questionnaire, have not been validated in the pediatric population. This remains an area in need of further research.
3-D printing is an emerging field that is beginning to show some utility in fitting patients with upper limb deficiency. It has not yet been widely applied to lower limb prostheses, however. Durability of available materials is a significant limiting factor.
Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills
The treatment of the limb-deficient child is maximized when the family and child are involved in the decision-making process.
The surgical and prosthetic options are often complex and must be suited to the individual’s needs.
4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE
Cutting edge concepts and practice
Continued improvements in pediatric-sized components offer technological advances in comfort, stability, cosmesis, and mobility. These include myoelectric or power-assist (motor-driven) knee and ankle units and elastomeric prosthetic coverings. Limitations in the use of these exist because of the lack of payer funding and applicability of the components to a growing, active, developing child.
5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE
Gaps in the evidence-based knowledge
The use of myoelectric prostheses in congenital upper limb deformities is commonplace; however, myoelectric lower limb prostheses have not been tested nor widely applied to children. In patients with partial tibial longitudinal deficiency, the utility and timing of knee sparing surgeries (e.g., fibular centralization procedure) remains controversial.
- Werler MM, Pober BR, Nelson K, Holmes LB. Reporting accuracy among mothers of malformed and nonmalformed infants. Am J Epidemiol. 1989;129:415-421.
- Yoon PW, Rasmussen SA, Lynberg MC, et al. The National Birth Defects Prevention Study. Public Health Rep. 2001;116 Suppl 1:32-40.
- Wilcox WR, Coulter CP, Schmitz ML. Congenital limb deficiency disorders. Clin Perinatol.2015 Jun;42(2):281-300.
- Caspers KM, Romitti PA, Lin S, et al. Maternal periconceptional exposure to cigarette smoking and congenital limb deficiencies. Paediatr Perinat Epidemiol. 2013:27(6),509-520.
- Garne E, Loane M, Dolk H, et al. Spectrum of congenital anomalies in pregnancies with pregestational diabetes. Birth Defect Res A Clin Mol Teratol. 2013:94 (3):134-140.
- Ordal L, et al. Congenital limb deficiencies with vascular etiology: Possible association with maternal thrombophilia. Am J Med Genet A. 2016 Dec;170(12):3083-3089.
- Dillingham TR, Pezzin LE, MacKensie EJ. Limb amputation and limb deficiency: epidemiology and recent trends in the US. South Med J. 2002;95:875-883.
- Canfield MA, Honein MA, Yuskiv N, et al. National estimates and race/ethnic-specific variation of selected birth defects in the United States, 1999-2001. Birth Defects Res A. 2006;76:747-756.
- Desrosiers TA, Herring AH, Shapira SK, et al. Paternal occupation and birth defects: findings from the National Birth Defects Prevention Study. Occup Environ Med. 2012;69:534-542.
- Herring JA, Birch JG, eds. The Child With a Limb Deficiency. 1st ed. Rosemont, IL: American Academy of Orthopedic Surgeons; 1998.
- McGuirk CK, Westgate MN, Holmes LB. Limb deficiencies in newborn infants. Pediatrics. 2001;108:E64.
- Krajbich JI,Pinzur MS, Potter LTC BK, Stevens PM, eds. Atlas of Amputations and Limb Deficiencies: Surgical Prosthetic, and Rehabilitation Principles. 4th ed. Rosemont, IL: American Academy of Orthopedic Surgeons; 2016.Vol.3.
- Alexander MA, Matthews DJ, eds. Pediatric Rehabilitation: Principles and Practice. 4th ed. New York, NY: Demos Medical; 2010.
- Mindler GT, Radler C, Ganger R. The unstable knee in congenital limb deficiency. J Child Orthop.2016 Dec;10(6):521-528.
- Bjornson KF, Yung D, Jacques K, Burr RL, Christakis D. StepWatch stride counting: accuracy, precision, and prediction of energy expenditure in children. J Pediatr Rehabil Med. 2012;5:7-14.
Original Version of the Topic
Phoebe R. Scott-Wyard, DO. Congenital Lower Limb Deficiency. 12/02/2013.
Phoebe R. Scott-Wyard, DO
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