title: Partial meniscectomy provides no benefit for symptomatic degenerative medial meniscus posterior root tears.
abstract: OBJECTIVE
  Medial meniscus posterior root tears (MMPRTs) are recognized as a source of pain and dysfunction, but treatment options remain a challenge. The purpose of the study was to determine (1) the efficacy of partial meniscectomy to treat MMPRTs compared to a matched group of non-operatively treated MMPRTs, and (2) risk factors for worse clinical and radiographic outcome.
  
  
  METHODS
  This retrospective comparative study was performed to include patients with complete, isolated MMPRTs with documented clinical symptoms and were treated with arthroscopic partial meniscectomy (PMM) and a minimum 2-year follow-up. These patients were then matched by age, gender, and BMI to patients with the same diagnosis who were treated non-operatively. Clinical and radiographic outcomes were compared between the two groups. Analysis was performed to determine risk factors for worse clinical and radiographic outcome in the PMM group alone.
  
  
  RESULTS
  Overall, 52 patients were included in the study. Twenty-six patients (9M:17F) with a mean age of 55 ± 9 and a mean BMI of 32.8 ± 5.3 were treated with PMM and followed for 5.5 ± 2.0 years (range 2.3-9.3 years). In the PMM group, final median Tegner score was 3, mean IKDC score was 67.8 ± 20, and more patients had grade II or higher arthritis at final follow-up than baseline (91.3 vs. 36%, p < 0.01). Overall, 14 of the 26 patients (54%) treated operatively progressed to total knee arthroplasty at a mean of 54.3 months. There was no significant difference in final Tegner scores, IKDC, K-L grades, progression to arthroplasty, or overall failure rate between the PMM group and non-operative group. Following PMM, female patients had lower final IKDC scores (44.0 ± 2.8 vs. 74.6 ± 16.7, p = 0.02) compared to males, as well as a higher rate of arthroplasty (70.6 vs. 20.0%, p = 0.009). Higher BMI correlated with lower IKDC scores (r = -0.91, p = 0.01) and meniscal extrusion was associated with higher rate of arthritis at final follow-up (p = 0.02).
  
  
  CONCLUSIONS
  Partial meniscectomy for a complete MMPRT provides no benefit in halting arthritic progression. Patients who undergo PMM for MMPRTs still progress to significant arthritis, poor clinical outcomes and a high arthroplasty rate (54%) at over 5-year follow-up. Female gender, increased BMI, and meniscus extrusion were associated with worse outcome.
  
  
  METHODS
  Level III.
authors.affiliation: Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA. Krych.Aaron@Mayo.edu.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Krych
authors.affiliation: Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
authors.forename: Nick R
authors.initials: NR
authors.lastname: Johnson
authors.affiliation: Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
authors.forename: Rohith
authors.initials: R
authors.lastname: Mohan
authors.affiliation: Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
authors.forename: Diane L
authors.initials: DL
authors.lastname: Dahm
authors.affiliation: Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Levy
authors.affiliation: Department of Orthopedic Surgery and Sports Medicine, Mayo Clinic, 200 First St SW, Rochester, MN, 55905, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Stuart
mesh_terms: D000368:Aged; D001182:Arthroscopy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D000074403:Meniscectomy / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D000070600:Tibial Meniscus Injuries / Q000601:surgery*; D016896:Treatment Outcome
keywords: Arthritis; Matched cohort; Medial meniscus posterior root tear; Meniscectomy