Retraction note to four articles published in World Journal of Orthopaedics

: [This retracts the article on p. 26 in vol. 1, PMID: 22474624.][This retracts the article on p. 37 in vol. 2, PMID: 22474634.][This retracts the article on p. 7 in vol. 2, PMID: 22474626.][This retracts the article on p. 316 in vol. 4, PMID: 24147269.].