In vivo measurement of tissue metabolism in tendons of the rotator cuff.

Correspondence We welcome letters to the Editor concerning articles which have recently been published. Such letters will be subject to the usual stages of selection and editing; where appropriate the authors of the original article will be offered the opportunity to reply. Letters should normally be under 300 words in length, double-spaced throughout, signed by all authors and fully referenced. The edited version will be returned for approval before publication. In vivo measurement of tissue metabolism in tendons of the rotator cuff Sir, I read with interest the article by Matthews et al 1 in the May 2007 issue entitled " In vivo measurement of tissue metabolism in tendons of the rotator cuff: implications for surgical management ". The problem of high failure rates in repair of the rotator cuff is an important one. The authors have demonstrated reduced cellular activity in torn tendons and propose that this contributes to the high failure rate in repair, particularly of large tears. However, the results do not clearly demonstrate that cellular activity predicts the healing potential of the tendons. While tendon degeneration before the tear occurred may be a factor in the reduced cellular activity, the effect of duration of the tear does not seem to have been considered. I note that the minimum duration of pre-operative symptoms was two months, with most cases having symptoms for more than 12 months. There is a trend in the results which suggests less cellular activity with a longer duration of symptoms and hence, presumably, time since the tear occurred. Once torn there will be a reduction in mechanical stress on the tendon which might affect cellular activity. When tendons rupture at sites other than the shoulder, e.g. avulsion of flexor digitorum profundus from its insertion, there is rapid shortening of both the muscle and the tendon over a matter of weeks. The tendon also appears degenerate at operation if there has been delay in repair. Almost all tendon ruptures which benefit from surgery are routinely repaired as an urgent procedure. Delay is known to compromise results. Have any studies looked at cellular activity in other torn tendons? I would suggest that the main reason for high failure rates in rotator cuff repair is delay. While not all tears occur acutely, early diagnosis and surgery, at least for acute tears, may offer the best strategy for improving results. et al. In vivo measurement of tissue …