Magnetic resonance assessment of medial plica syndrome of knee from child to adult with arthroscopic correlation: A single center experience and literature review

OBJECTIVE: Synovial plicae are mesenchymal tissue remnants invaginating into the knee joint. Their classification is based on the location as lateral, mediopatellar, suprapatellar, and infrapatellar. Mediopatellar plica is commonly symptomatic. The purpose of this study was to identify magnetic resonance (MR) characteristics of the medial plica and to correlate with arthroscopy for cause confirmation in patients with painful knee. MATERIALS AND METHODS: The current study was undertaken over a 2-year period between July 2017 and June 2019 in the department of radiology at a tertiary care hospital in India. MR examinations of the knee joint were performed using QUADKNEE coil on a 1.5-T scanner (Signa, General Electric Medical Systems, Milwaukee, WI, USA). The criteria studied were: presence of the plica, interposition into the femoropatellar joint, intraarticular effusion, and fenestrated aspect. Twenty-two knees (20 patients) diagnosed with mediopatellar plica syndrome on MR imaging (MRI), and with no other knee pathology, were treated with arthroscopic division of plicae. RESULTS: Only two (20.0%) of the ten knees in which the plicae had not been divided have shown improvement and six (85.7%) of the seven knees in which plica had been divided (P < 0.05) have shown improvement. Subsequent division of the plicae resulted in improvement in seven of the eight knees (87.5%) (P < 0.01). Patients presented with crepitus in 9% of cases (2 of 22), instability in 13.6% (3 of 22), pseudo-locking in 45.4% (10 of 22), and quadriceps atrophy in 54.5% (12 of 22). Fourteen knees (63.6%) had Grade 2 plica based on thickness. Twelve knees demonstrated (54.5%) Grade 2 intermediary effusion. Plica was fenestrated in three patients (13.6%). All patients regained full range of motion. Lysholm knee scale scores were compared prior to and postsurgery (preoperative status, 65.22 ± 7.41 vs. postoperative status, 89.43 ± 8.72) which revealed a significant clinical improvement (P < 0.001). Average visual analog scale (VAS) scores (0 – no pain, 10 – excruciating pain) when compared demonstrated a mean improvement was 4 points; from 6 points before surgery and 2 points' postsurgery after a mean follow-up of 3 months. About 68% of patients after arthroscopic resection had an average VAS score of 0 point and were totally pain free. CONCLUSION: Noninvasive capability of MRI can be used as a screening method in the diagnosis of mediopatellar plica syndrome and should be included in the differential diagnosis of internal derangement of the knee.