TENDON TRANSFERS: DOES THE DURATION OF IMMOBILISATION AFFECT SCARRING AND ADHESIONS. A RABBIT MODEL

Abstract

Introduction: In orthopaedic surgery, tendon transfers are used routinely. Examples are the correction of deformities due to spasticity in infantile cerebral palsy or clump foot surgery. Aftertreatment is not evidence based but depends mostly on the surgeons personal preferences. This is especially true for the duration of postoperative immobilization. Adhesions between tendon and surrounding tissue are supposedly a key factor for reduced functionality after immobilisation and it appears to be common sense that the amount of scarring depends on the duration of immobilisation.

The purpose of this study was to determine the optimal (im)mobilisation schema, protecting the suture as well as avoiding impairment of the capability of the transferred tendon to slide properly.

Methods: A tendon transfer of the m. flexor digitorum longus to the dorsal talus was performed in 32 New-Zealand rabbits. The tendon was passed through a drill hole and sutured to itself. Animals were randomised into 6 groups. Groups 1 to 3 experienced mobilisation of varying duration (none, 2 and 4 weeks) after two weeks of immobilisation. Groups 4 to 6 received the same time of mobilisation (4 weeks) but after different periods of immobilisation (4, 6, 8 weeks).

Histomorphological examinations including synovial cell coating, appearance of tendon and tissue interface, inflammation and scarring of the site of surgery were done. The results were analyzed statistically (Kruskal-Wallis-test; Jonckheere Terpstra-test).

Results: Except a difference in development of a synovial cell coating of questionable clinical significance there were no significant findings regarding the histomorphology between the different groups.

Conclusion: In opposition to traditional believes, our results suggest that the influence of postoperative mobilisation or immobilisation towards the formation of scarring and adhesions in tendon transfers may by widely overestimated. This implies that the decision for the duration of postoperative immobilisation should be mainly based on safe ingrowths, without the imminent risk of loss of function.