About the PhD thesis

Twenty years ago, the established treatment for bone lengthening was external fixation, which had the major disadvantage of high complication rates. Since then, the externally controlled bone lengthening nail was introduced to reduce complications. However, established evidence concerning the complications of bone lengthening nails remains lacking in the literature. The aim of the PhD investigation was therefore complications related to treatment with externally controlled bone lengthening nails.

The body of literature was explored through a systematic review in study I, which assembled a group of 983 segments. Device, bone, and joint complications were the most frequent complication origins, and the overall frequency of complications was one complication for every three segments lengthened.

A retrospective two-center cohort study of 314 segments provided the basis for the second study, showing a complication frequency of one complication for every two segments lengthened. As in the systematic review, device, joint, and bone were the three most frequent origins of complication. The following risk factors with a significantly increased relative risk of complication were discovered: age groups ≥30 years, FITBONE nail, tibia segment, acute deformity correction combined with lengthening, and increasing bone lengthening.

In the third study, the intra- and inter-rater reproducibility of the complication severity and origin classification system used in study I & II was evaluated. A good inter-rater and good to excellent intra-rater agreement for the severity and origin classification was found in the two examined case groups.

In short, the thesis presents evidence on the frequency, origin, and severity of complications in bone lengthening nails. The results of this thesis suggest that complications in the treatment of bone lengthening nails frequently occur and that risk factors of complications exist. Both implications provide valuable knowledge in the assessment and the treatment of bone lengthening patients.

Photo: Line Bloch Klostergaard/The North Denmark Region