Effects of posterior tibial tendon augmented with biografts and calcaneal osteotomy in stage II adult-acquired flatfoot deformity

Tendon transfer options in managing the adult flexible flatfoot

Patients undergoing surgery for posterior tibial tendon dysfunction may require tendon transfer. The flexor digitorum longus is most commonly transferred, although the flexor hallucis longus and peroneus brevis have also been described in the literature. This article discusses the advantages and disadvantages of the different tendons, the surgical techniques used to perform them, and their results in the literature, concentrating principally on studies in which additional bone procedures were not performed. This article will also discuss the potential role for isolated soft tissue procedures in the treatment of stage 2 posterior tibial tendon dysfunction.

Changes in matrix protein biochemistry and the expression of mRNA encoding matrix proteins and metalloproteinases in posterior tibialis tendinopathy

Objectives

Adult-acquired flat foot secondary to a dysfunctional posterior tibialis tendon (PTT) is often treated by surgical transfer of the flexor digitorum longus tendon (FDLT). In this study, the authors compared normal PTT, stage II dysfunctional PTT and replacement FDLT, aiming to define changes in collagen modification, glycosaminoglycan (GAG) and the expression of matrix and metalloproteinase mRNA.

Methods

Normal PTTs were obtained from patients with no history of tendon problems. Samples of dysfunctional PTT and replacement FDLT tissue were obtained from patients undergoing surgical reconstruction. Tissue samples were analysed for total collagen and GAG, pentosidine and collagen cross-links. Total RNA was assayed for mRNA encoding matrix proteins and metalloproteinases, using real-time reverse transcription PCR. Differences between clinical groups were assessed using non-parametric statistics.

Results

Dysfunctional PTT contained higher levels of GAG and lower levels of pentosidine than normal PTT or FDLT. In contrast, collagen in FDLT contained fewer ketoimine and more aldimine cross-links than either normal or dysfunctional PTT. mRNA encoding types I and III collagens, aggrecan, biglycan, matrix metalloproteinase (MMP)-2, -13 and -23, and a disintegrin and metalloproteinase (ADAM)-12L each showed increased levels in dysfunctional PTT compared with either normal PTT or (except MMP-13) FDLT. In contrast, MMP-3 and ADAM with thrombospondin domain (ADAMTS)-5 mRNA were lower in both dysfunctional PTT and FDLT than in normal PTT, while ADAMTS-1 mRNA was lower in dysfunctional PTT than in FDLT.

Conclusions

Stage II dysfunctional PTT shows biochemical and molecular changes consistent with a chronic remodelling of the extracellular matrix, rather than rupture, while the replacement FDLT resembles normal PTT in many, but not all, parameters.

Bioscaffolds and the reconstruction of ligaments and tendons in the foot and ankle

Biologic scaffolds have become an integral part of surgical soft tissue reconstruction in recent years. The increased use of these materials can be partially attributed to poor long-term outcomes with synthetic products as well as the cost and morbidity associated with allografts and autografts. Bioscaffolds can augment natural healing processes of tendons and ligaments while providing additional structural support. Although these implants lack the mechanical strength of synthetics and other transplants, proper preparation can optimize their load-sharing capacity. This article presents methods that can improve these characteristics of bioscaffolds. Available studies in foot and ankle applications have shown minimal complications in a variety of techniques.