OBJECTIVE: This systematic review and meta-analysis was performed to identify the clinical trials relevant to the effects of low-intensity pulsed ultrasound (LIPUS) on bone regeneration.
DESIGN: We searched five international electronic databases including MEDLINE (1966-June 2010), and PubMed, EMBase, Cumulative Index to Nursing and Allied Health, and Cochrane (1980-June 2010) to identify the relevant studies on the effects of LIPUS on bone healing. The inclusion criteria were human clinical trial, all types of bones, fractures, and outcome measurements, LIPUS application, and English language. Overall, 260 potentially eligible abstracts were identified, and 65 articles were retrieved in full text. Of the 65 studies, 23 met the inclusion criteria and were critically appraised by two raters independently using the PEDro quality measurement method. The results of all eligible studies were categorized in three groups: fresh fractures, delayed or nonunions, and distraction osteogenesis. Seven trials among fresh fracture trials were identified eligible for meta-analysis because of the varieties of outcome measurements and clinical situations. The time of the third cortical bridging (increase in density or size of initial periosteal reaction) in radiographic healing was our common criteria for the meta-analysis.
RESULTS: The time of third cortical bridging was statistically earlier following LIPUS therapy in fresh fractures (mean random effect, 2.263; 95% CI, 0.183-4.343, P = 0.033).
CONCLUSIONS: LIPUS can stimulate radiographic bone healing in fresh fractures. Although there is weak evidence that LIPUS also supports radiographic healing in delayed unions and nonunions, it was not possible to pool the data because of a paucity of sufficient studies with similar outcome measures.