Delayed rupture of the thumb extensor tendon

Sir-In the article “Delayed rupture of the thumb extensor tendon, a 5-year study of 18 consecutive cases”, Hove (1994) reports nearly complete satisfaction after tendon transfer for extensor pollicis longus rupture, with which we concur. He concludes that all patients were able to raise their thumbs to the level of the palm. In a recent similar study (Noorda and Hage 1994). we found different results. On the basis of Geldmacher’s (1986) evaluation scheme for assessment of the results of extensor tendon reconstruction our patients scored less favourably, especially with regard to raising the thumb to the plane of the hand. The mean score for thumb elevation in our series was 1.6 out of 6 points, corresponding to a lag of 2.1-3 cm when compared with the opposite thumb. This accords with the findings of Magnussen et al. (1990). Unlike Hove and Magnussen et al. (1990) we found no flexion deficit. Hove further concludes that full index extension was achieved either when all fingers were extended simultaneously (dependent) or when the remaining fingers were flexed (independent). In a recent study (Noorda et al. 1994). we reviewed the long-term morbidity of the donor index finger following extensor indicis proprius transfer. An extension lag of the donor index was found in 71 percent. Hove admitted that, in spite of achieving full extension, a few patients had to use more force than on the contralateral side when extending the index finger independently. We observed a significantly reduced extension strength of the donor index finger in all patients, whether measured dependently or independently. In spite of these results we, like Hove and like Littler (1967), feel that the extensor lag is not caused by the removal of the force of the motor per se. The integrity of the dorsal hood and noninterference with intrinsic or extrinsic tendon amplitude is of utmost importance. For this reason, we gratefully acknowledge that an alternative method should be considered for patients in whom individual extension of the index finger is of importance.