• Orthopaedic Pediatrics

Controlled growth of bones using different closed and surgical techniques can be used as treatment in a number of conditions in paediatric orthopaedics. The growing skeleton is susceptible to manipulation of the growth plate and by doing this it may be possible to avoid more extensive surgical procedures. With leg length discrepancy (LLD) a timed epiphysiodesis (closure of a growth plate) on the longest leg can be used as treatment in milder cases. Commonly today a permanent technique with closure of the growth plate is being used. This necessitates timing of the procedure to ensure equalisation of the legs at skeletal maturity. Performing a temporary closure of the growth plate is appealing as intervention then can be performed at an earlier stage. Unilateral epiphysiodesis (or hemiepiphysiodesis) can be used to correct angulating deformities. Traditionally staples have been used to perform a reversible hemiepiphysiodesis. During the last decade a new principle called tension band plating using a small extra periosteal plate and two screws has gained popularity. Tension band plating has been described to have a theoretical advantage compared to stapling. Several clinical and experimental studies has investigated the use of tension band plating but it still remains unclear if the tension band plating technique has a more biological effect on the growth plate than stapling.

The aim of the thesis was to investigate the use of tension band plating in relation to angulating deformities and LLD.

In Paper I growth plate morphology was compared after tension band plating and stapling in an animal experimental study. Both the immediate response and the delayed response after hemiepiphysiodesis were studied using quantitative histomorphometry. The ability to perform a temporary epiphysiodesis using tension band plating in a similar animal model was investigated in Paper II. In this study the animals were followed with magnetic resonance imaging. The outcome was changes in interphyseal distance and metaphyseal water content. Finally in Paper III, stapling and tension band plating was compared in a randomized clinical study in children with idiopathic genu valgum. Treatment time as well as changes in intermalleolar distance and radiographic parameters was evaluated.

The results showed similar changes in growth plate morphology between stapling and tension band plating in Paper I. The delayed response to hemiepiphysiodesis appears to be growth plate enlargement and disorganisation of cartilage tissue (Paper I). It was possible to induce a temporary growth control in the animal model in paper II with a shortening of the treated bone. Furthermore, changes in metaphyseal water content were correlated with bone growth. In Paper III no differences were found between stapling and tension band plating in relation to treatment time, intermalleolar distances, and measured radiographic values on long standing x-rays.

In conclusion, the theoretical advantage of tension band plating towards stapling is probably of minor importance in clinical practice. Temporary epiphysiodesis using tension band plating may have a role in treatment of LLD, but future clinical studies are needed to investigate this.

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