Are internal lengthening devices effective and associated with less complications compared to other lengthening devices? A systematic review and meta-analysis.

Abstract

Internal lengthening devices became more popular than external fixators. This was attributed to their effectiveness and lower complication rates. However, this is an assumption that is not on the basis of solid scientific evidence. Therefore, this study systematically reviewed the quality and strength of evidence supporting femoral internal lengthening devices' effectiveness and their associated complications. Six electronic databases (PubMed, Cochrane, Sage, Embase, Web of Science and Scopus) were searched from inception until 20 June 2020. Further, all included articles' bibliographies were searched manually. After screening of retrieved articles, five studies were eligible for qualitative and quantitative synthesis. Studies were assessed by two independent assessors using a modified 'assessment of the methodological quality both of randomized and nonrandomized studies of health care interventions'. Further, meta-analysis was conducted to compare the procedure's effectiveness, in terms of healing index and major complications incidence. Our findings showed internal validity as the major source of bias whereas external validity was the least. For healing index, there is limited evidence that internal lengthening devices lower healing index by 0.45 months/cm (95% CI, -0.62 to -0.28; P < 0.01) compared to LON/external fixators. The incidence of major complications, that were directly related to the procedures, did not differ between internal lengthening devices and other fixators (risk ratio=0.97; 95% CI, 0.39-2.44; P < 0.95). This review provides evidence that supports lower healing index and similar complications associated with internal lengthening devices compared to other procedures of femoral lengthening. However, the evidence is very limited to draw a solid conclusion.