Outcome Equivalence

We would like to thank the authors for their comprehensive article (1). The following key aspects should be added:

1. When reporting „300000 meniscus surgeries“ based on the DRG hospital statistics of the German Federal Statistical Office, it should be taken into consideration that the Federal Statistical Office counts procedures, rather than cases. Since an arthroscopic operation often requires several procedures, each individual case/patient appears many times in the procedure count. Thus, it can be assumed that the actual number of patients operated on primarily due to a meniscus injury is significantly lower.

2. The study by Sihvonen et al. (2) contains a massive selection bias. Over a study period of six years and with the participation of five centers, only 145 patients were enrolled—thus representing a highly-selected patient population. These results therefore cannot be generalized to the entire population of patients with degenerative meniscus damage.

3. The alleged equivalence between arthroscopy and physiotherapy in the study by Katz et al. (3) is obtained only when using the intention-to-treat method, with a crossover rate of 35% from the conservative to the operative group. In an appendix to their work, the authors themselves clarified that using an alternative statistical analysis revealed arthroscopy to be superior to conservative treatment.

Overall, it is incorrect to state that arthroscopy and physiotherapy have outcome equivalence for treating degenerative meniscus damage. Indeed, the authors correctly concluded that arthroscopic partial meniscectomy will still have an important role in the future, and that a significant proportion of patients do not benefit from conservative treatment.