[The effect of arthroscopic synovectomy on refractory knee arthritis with popliteal cyst in 153 patients]

Objective: To investigate the efficacy of arthroscopic synovectomy on refractory knee arthritis complicated with popliteal cyst. Methods: Patients diagnosed as rheumatoid arthritis (RA) or spondyloarthritis (SpA) with refractory knee arthritis who underwent knee arthroscopic synovectomy in our hospital from 2010 to 2017 were enrolled, including 20 patients (16 RA, 4 SpA) with popliteal cyst. Clinical data, RA disease activity score (DAS28), SpA back pain score, etc, were collected to evaluate the efficacy of knee surgery. Results: Erythrocyte sedimentation rate (ESR) [58(17, 79)mm/1h vs. 19(9, 30)mm/1h, P< 0.001],C reactive protein (CRP) [3.72(0.92,8.14) mg/L vs. 0.85(0.10,3.08) mg/L,P<0.001], rheumatoid factor [64.6(20.2,193.3) vs. 20.5(10.0,58.4),P<0.001], DAS28 score(4.67±1.25 vs. 2.81±1.23,P<0.001), knee joint discomfort score [5(4,6) vs. 2(1,3),P<0.001] and the volume of knee joint effusion by ultrasound (P<0.05) in 95 RA patients were significantly decreased compared to those before operation. ESR [27(12,54)mm/1h vs. 20 (16,28) mm/1 h,P<0.001], CRP [3.27(1.06,6.95) mg/L vs. 1.41(0.34,3.03)mg/L,P<0.001],knee discomfort score [2(0,5) vs. 1(0,3),P<0.05], back pain visual analogue score (VAS) [5(4,5) vs. 2(1,3), P<0.001], and the volume of knee joint effusion by ultrasound (P<0.001) in 58 SpA patients were significantly lower than those before the operation.The rate [16.84%(16/95) vs. 6.32%(6/95),P=0.023] and grading (P=0.007) of popliteal cyst in RA were decreased after the operation. No statistically difference was observed in the rate [6.90% (4/58) vs. 5.17%(3/58), P=0.697] of popliteal cyst in patients with SpA, yet with a trend of decrease in 4 patients. Conclusion: This study provide evidence that knee arthroscopic synovectomy has a good effect for refractory knee arthritis, which can reduce disease activity, improve joint symptoms and decrease the grading of popliteal cyst.