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Better outcome from arthroscopic partial meniscectomy than skin incisions only? A sham-controlled randomised trial in patients aged 35–55 years with knee pain and an MRI-verified meniscal tear
  1. Ewa M Roos1,
  2. Kristoffer Borbjerg Hare1,2,
  3. Sabrina Mai Nielsen3,
  4. Robin Christensen3,
  5. L Stefan Lohmander4
  1. 1 Department of Sport and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
  2. 2 Department of Orthopaedics, Slagelse Hospital, Slagelse, Denmark
  3. 3 Musculoskeletal Statistics Unit, The Parker Institute, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
  4. 4 Department of Clinical Sciences Lund, Orthopaedics, Lund University, Lund, Sweden
  1. Correspondence to Dr Ewa M Roos; eroos{at}


Objective Compare arthroscopic partial meniscectomy to a true sham intervention.

Methods Sham-controlled superiority trial performed in three county hospitals in Denmark comparing arthroscopic partial meniscectomy to skin incisions only in patients aged 35–55 years with persistent knee pain and an MRI-confirmed medial meniscus lesion. A computer-generated table of random numbers generated two comparison groups. Participants and outcome assessors were blinded to group allocation. Exclusions were locking knees, high-energy trauma or severe osteoarthritis. Outcomes were collected at baseline, 3 and 24 months. We hypothesised no difference between groups. The primary outcome was the between-group difference in change from baseline to 2 years in the mean score across all five normalised Knee injury and Osteoarthritis Outcome Score (KOOS) subscales (KOOS5).

Results Forty-four patients (of the estimated 72) underwent randomisation; 22 in each group. Sixteen participants (36%) were non-blinded and eight participants (36%) from the sham group crossed over to the surgery group prior to the 2-year follow-up. At 2 years, both groups reported clinically relevant improvements (surgery 21.8, skin incisions only 13.6), the mean difference between groups was 8.2 in favour of surgery, which is slightly less than the cut-off of 10 prespecified to represent a clinically relevant difference; judged by the 95% CI (−3.4 to 19.8), a possibility of clinically relevant difference could not be excluded. In total, nine participants experienced 11 adverse events; six in the surgery group and three in the skin-incisions-only group.

Conclusion We found greater improvement from arthroscopic partial meniscectomy compared with skin incisions only at 2 years, with the statistical uncertainty of the between-group difference including what could be considered clinically relevant. Because of the study being underpowered, nearly half in the sham group being non-blinded and one-third crossing over to surgery, the results cannot be generalised to the greater patient population.

Trial registration number NCT01264991.

  • knee
  • adult orthopaedics
  • musculoskeletal disorders
  • orthopaedic sports trauma

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  • Contributors EMR contributed to designing the study, the statistical analysis plan, interpreting the data and drafted the first manuscript. KBH contributed to designing the study, was responsible for patient recruitment and data collection, contributed to the final statistical analysis plan and approved the manuscript. SMN contributed to the final statistical analysis plan and analysing/interpreting the data. RC contributed to designing the study, the original and final statistical analysis plan and interpreting the data. LSL contributed to designing the study, the statistical analysis plan and interpreting the data. All authors provided intellectual input, revised and approved the final manuscript.

  • Funding Research Fund of Hospital South, Region Zealand; Region Zealand Health Scientific Research Fund; Edith and Henrik Henriksens Memorial Fund; The Danish Rheumatism Association. The Parker Institute, Bispebjerg and Frederiksberg Hospital (R. Christensen and S.M. Nielsen) is supported by a core grant from the Oak Foundation (OCAY-13-309).

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Research Ethics Committee of Region Zealand, Denmark.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data available.

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