The influence of synovial inflammation and hyperplasia on symptomatic outcomes up to 2 years post-operatively in patients undergoing partial meniscectomy

Abstract

Objective: Synovitis is associated with pain and other symptoms in patients with knee osteoarthritis (OA), and in patients with meniscal tears even in the absence of radiographic OA. Patients undergoing arthroscopic partial meniscectomy were followed for 2 years to determine whether synovitis predicts post-operative symptoms.

Design: Thirty-three patients scheduled for arthroscopy were recruited for this pilot study. Symptoms were assessed using a knee pain scale, the Lysholm score, and the short form-12 (SF-12(®)) pre-operatively and at 16 weeks, 1 year and 2 years post-operatively. Synovial inflammation and hyperplasia were graded on surgical biopsies. Linear mixed effects models were tested to determine whether inflammation or hyperplasia is associated with outcome scores over time.

Results: Lysholm scores and SF-12(®) physical component sub-scores were worse pre-operatively in patients with inflammation (Lysholm: 52.42 [95% confidence interval (CI) 42.37, 62.47] vs 72.38 [66.03, 78.72], P < 0.001; SF-12: 36.81 [28.26, 45.37] vs 46.23 [40.14, 52.32], P < 0.05). Up to 2-years post-operatively, patients with inflammation achieved mean scores similar to those without inflammation. As a result, the mean improvement in Lysholm scores was 13.01 [1.48-24.53] points higher than patients without inflammation, P = 0.03. 33% (4/12) of patients with inflammation still had fair to poor Lysholm scores 2 years after surgery compared to 7% (1/15, P=0.14) without inflammation. No association between hyperplasia and symptoms was noted.

Conclusions: In this pilot study of patients undergoing partial meniscectomy, synovial inflammation was associated with worse pre-operative symptoms, but not with poorer outcomes in the first 2 years post-arthroscopy. Larger cohorts and longer follow-up should be pursued to confirm this relationship, and determine if the initial response is sustained.

Keywords: Arthroscopy; Inflammation; Meniscal tear; Osteoarthritis; Synovitis.

Figure 1. Distribution of synovial histology scores in the three biopsy sites

(A) Lining hyperplasia, (B) Vascularity, (C) Inflammation , and (D) Fibrosis were graded on H&E stained sections as described in Materials and Methods. Twenty-eight patients provided synovial biopsies from all three sites. The medial and lateral gutter biopsies were described as ipsilateral or contralateral to the meniscal tear in each individual. 0–2 on the x-axes represents the histologic grade (Table 1).

Figure 2. Pre- and post-operative symptom scores in patients undergoing meniscetomy over two years, stratified by presence or absence of synovial inflammation

Questionnaires and surveys were administered to patients pre-operatively (pre-op), as well as at 16 weeks (wks), 1 year (yr) and 2 years post-operatively as described. Improvements in all measures except the SF-12^® MCS subscores were observed after surgery. Patients with inflammation are indicated by red triangles, patients without are indicated by black circles. (A) Lysholm scores, (B) Pain scale, (C) SF-12^® PCS subscores, (D) SF-12^® MCS subscore.