Background: The aims of this study were to determine the prevalence of congenital lower-limb reduction defects and associated mortality, to evaluate lower-limb deficiencies by type of reduction, and to identify patterns of associated anomalies.
Methods: We conducted a population-based study with use of data from the Finnish Register of Congenital Malformations and Care Register for Health Care. All cases of lower-limb deficiency among live births, stillbirths, spontaneous abortions, and terminations of pregnancy due to fetal anomalies from 1993 to 2008 were included. We analyzed medical records and classified lower-limb reduction defects. Associated major anomalies were recorded, and perinatal mortality and infant mortality were calculated.
Results: Two hundred and sixty-six cases with lower-limb deficiency were identified, with a total prevalence of 2.8 per 10,000 births, a birth prevalence of 2.2 per 10,000 births, and a live-birth prevalence of 2.1 per 10,000 live births. Terminal transverse limb reductions accounted for 44.7% of the cases; longitudinal reductions, 22.9%; intercalary reductions, 7.9%; multiple reductions, 8.3%; and split-foot malformations, 4.5%. In addition to lower-limb deficiency, 47.7% of the cases had other major anomalies; anomalies of internal organs were noted in 26.3% of the cases, anomalies of the axial skeleton in 13.5% of cases, and central nervous system anomalies in 12.8%. Upper-limb reductions were observed in 32.0% of the cases. The relative risk (RR) for associated major anomalies was 12.54 (95% confidence interval [CI], 11.06 to 14.23) compared with the general figures for major congenital anomalies in Finland. The RR for associated anomalies was higher (1.75; 95% CI, 1.20 to 2.53) for longitudinal preaxial lower-limb deficiencies than for the other types of lower-limb reductions. Perinatal mortality was seventy-eight per 1000 births. All infant deaths were associated with chromosomal abnormalities, other known syndromes, or additional congenital malformations.
Conclusions: Nearly half of the cases with lower-limb deficiencies were found to have other major anomalies. In cases of preaxial lower-limb deficiencies, the risk for associated major anomalies was highest.
Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
1Departments of Paediatric Orthopaedic Surgery (J.S., E.K., and I.H.) and Orthopaedic Surgery (J.S.), Turku University Central Hospital, Kiinamyllynkatu 4–8, 20520 Turku, Finland. E-mail address for J. Syvänen: email@example.com
2Department of Paediatric Orthopaedic Surgery, Helsinki University Central Hospital, Stenbäckinkatu 11, 00290 Helsinki, Finland
3Finnish Register of Congenital Malformations, National Institute for Health and Welfare, PL 30, 00271Helsinki, Finland
4Biostatistics, University of Turku, Turku, Finland