A more correct interpretation
=============================

* Ewa M. Roos
* Jonas B. Thorlund
* Carsten B. Juhl
* L. Stefan Lohmander

A systematic review and meta-analysis of arthroscopic surgery for degenerative tears of the meniscus was recently published on cmaj.ca.1 We commend the authors for their timely work summarizing the available scientific evidence.

The authors evaluated “the efficacy of arthroscopic meniscal débridement in comparison with nonoperative or sham treatments.” This is correct for the study comparing arthroscopic surgery to sham surgery,2 the study comparing arthroscopic surgery to steroid injection3 and the study comparing arthroscopic surgery to medical exercise therapy.4 However, this aim is incorrectly stated for the studies by Herrlin and colleagues,5 Katz and colleagues,6 and Yim and colleagues,7 where exercise was a component of treatment provided to both groups. These three latter studies together comprise the majority of patients, 522 out of 805, included in this meta-analysis, and they studied the additional effect of a combination of arthroscopic surgery and exercise in comparison with exercise alone. Thus, a comparison of the effects from arthroscopic surgery alone to exercise alone is not possible.

A more correct interpretation of the results from the meta-analysis would therefore be, “there is moderate evidence to suggest that there is no additional benefit of arthroscopic meniscal débridement for degenerative meniscal tears compared to exercise, and no benefit in comparison with sham surgery or injection therapy.”

## References

1.  Khan M, Evaniew N, Bedi A, et al. Arthroscopic surgery for degenerative tears of the meniscus: a systematic review and meta-analysis. CMAJ 2014;186:1057–64.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMToiMTg2LzE0LzEwNTciO3M6NDoiYXRvbSI7czoyMjoiL2NtYWovMTg3LzUvMzU4LjEuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

2.  Sihvonen R, Paavola M, Malmivaara A, et al. Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. N Engl J Med 2013;369:2515–24.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1056/NEJMoa1305189&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=24369076&link_type=MED&atom=%2Fcmaj%2F187%2F5%2F358.1.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000328863700009&link_type=ISI) 

3.  Vermesan D, Prejbeanu R, Laitin S, et al. Arthroscopic debridement compared to intra-articular steroids in treating degenerative medial meniscal tears. Eur Rev Med Pharmacol Sci 2013;17:3192–6.
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=24338461&link_type=MED&atom=%2Fcmaj%2F187%2F5%2F358.1.atom) 

4.  Osteras H, Osteras B, Torstensen TA. Medical exercise therapy, and not arthroscopic surgery, resulted in decreased depression and anxiety in patients with degenerative meniscus injury. J Bodyw Mov Ther 2012;16:456–63.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1016/j.jbmt.2012.04.003&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=23036877&link_type=MED&atom=%2Fcmaj%2F187%2F5%2F358.1.atom) 

5.  Herrlin S, Hallander M, Wange P, et al. Arthroscopic or conservative treatment of degenerative medial meniscal tears: a prospective randomised trial. Knee Surg Sports Traumatol Arthrosc 2007; 15:393–401.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1007/s00167-006-0243-2&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=17216272&link_type=MED&atom=%2Fcmaj%2F187%2F5%2F358.1.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000245431300014&link_type=ISI) 

6.  Katz JN, Brophy RH, Chaisson CE, et al. Surgery versus physical therapy for a meniscal tear and osteoarthritis. N Engl J Med 2013;368:1675–84.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1056/NEJMoa1301408&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=23506518&link_type=MED&atom=%2Fcmaj%2F187%2F5%2F358.1.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000318214400001&link_type=ISI) 

7.  Yim JH, Seon JK, Song EK, et al. A comparative study of meniscectomy and nonoperative treatment for degenerative horizontal tears of the medial meniscus. Am J Sports Med 2013;41:1565–70.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1177/0363546513488518&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=23703915&link_type=MED&atom=%2Fcmaj%2F187%2F5%2F358.1.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000330524000019&link_type=ISI)