Leg length change after opening wedge and closing wedge high tibial osteotomy: A meta-analysis

Background
Theoretical considerations suggest that leg length increases after opening wedge high tibial osteotomy (HTO) and decreases after closing wedge HTO; however, in vivo studies have yielded conflicting results. This meta-analysis therefore assessed changes in leg length after opening wedge and closing wedge HTO.
Methods
All studies comparing pre- and postoperative leg length in patients who underwent opening and/or closing wedge HTO were included. Two reviewers independently recorded data from each study in terms of sample size as well as preoperative and postoperative leg length of open wedge and/or closed wedge HTO groups.
Results
Four studies were included in the meta-analysis. Although pooled results showed leg length changes from before to after surgery were –6.93 mm (95% confidence interval [CI]: –17.53 to 3.67 mm; P = 0.20) in opening wedge HTO and 1.97 mm (95% CI: –7.13 to 11.07 mm; P = 0.67) in closing wedge HTO, respectively, these values were statistically not significant. However, the difference in the pooled mean leg length change from before to after surgery between opening wedge and closing wedge HTO was 8 mm, a difference that was significant (95% CI: 6.53 to 9.46 mm; P<0.001).
Conclusion
The change in leg length was not statistically significant for either opening or closing wedge HTO. However, leg length change from before to after surgery was 8 mm greater for opening wedge HTO than for closing wedge HTO.