Leave It or Repair It? Comparison of the Arthroscopic and Clinical Outcomes after High Tibial Osteotomy with or without Medial Meniscus Posterior Root Repair

Insufficient fracture, which is shown not only in MR but also in simple X-ray, is an important risk factor for aggravation of arthritis.Data: Background: There are limited data describing the long-term outcome of nonoperative treatment of medial meniscus posterior root tear (MMPRT).The purpose of this study was to investigate the natural history of MMPRT and find out prognostic factor for poor outcome of non-operative treatment.Methods: Patients who were diagnosed as MMPRT and initially treated with non-operative management were retrospectively reviewed.Patients with severe OA(Kellgren-Lawrence(K-L) grade 4) was excluded and 94 patients were enrolled.The mean follow-up period after diagnosis was 45.9 month (from 17.6 to 170.5).Demographic characteristics and radiographic features including hip-knee-ankle angle (HKAA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), joint line width and K-L grade in plain radiographs and meniscus extrusion, bone edema and insufficient fracture in MRI were assessed.Results: At initial assessment, Four (4.3%) patients were K-L grade 0, 17 (18.1%)patients were grade 1, 59 (62.8%) patients were grade 2 and 14 (14.9%)patients were grade 3.During follow-up period, K-L grade of 34 (36%) patients were aggravated and 60 (64%) patients were not.The average of joint width was 3.2mm at initial assessment, 2.9mm at 1 year, 2.9mm at 2 years, 2.9mm at 3 years and 2.7mm at final follow-up.The average of JLCA was 2.49 , 3.13 , 3.23 , 3.28 and 3.37 at initial, 1 year, 2 years, 3 years and final follow-up.Demographic data and radiographic features were compared between two groups; those whose K-L grade were aggravated and those whose K-L grade weren't.Only site of knee was different (73% vs. 27%, P¼0.033) and other demographic features were not significantly different between two groups.In radiographic features, insufficient fracture was higher in aggravated group (7% vs. 24%, P¼0.019 in X-ray and 10% vs. 35%, P¼0.003 in MR).Conclusions: K-L grade of most MMPRT patients(64%) didn't aggravated during follow-up period.Since insufficient fracture was risk factor for aggravation of arthritis, clinician should carefully assess the insufficient fracture and decide to treat.