RESUMO
BACKGROUND: The main goal of this study was to assess iatrogenic subchondral bone lesions following three different anterior cruciate ligament (ACL) reconstruction techniques and their association with early postoperative pain. METHODS: A multicenter prospective comparative study was conducted in 2012. Each center performed a specific ligamentoplasty technique: two used retrograde and the other antegrade tibial tunnel drilling. Peri- and postoperative analgesia and systematic early postoperative magnetic resonance imaging (MRI) protocols were standardized. The main assessment criterion was tibial subchondral lesions (microfractures or bone oedema) on MRI during the first postoperative week. Secondary criteria were the assessment of postoperative pain for two days using a Visual Analogical Scale (VAS 0-10) and consumption of analgesics. RESULTS: Forty-three patients were included in three centers, 15 in the "antegrade group" and 28 in the "retrograde group", mean age is 32.5±9.1years, 14 women/29 men. All included patients underwent postoperative MRI. There were no subchondral tibial microfractures, but oedema was significantly more frequent in the antegrade group (p=0.0001). Tibial subchondral oedema was correlated to greater early postoperative pain (p=0.01). Multivariate analysis identified tibial tunnel diameter as an independent factor of early postoperative pain. The smaller the tibial tunnel diameter, the greater the mean early postoperative pain (≤8mm (18 patients) 3.4±1.5 vs. >8mm (25 patients) 1.8±1.7, p=0.004) and the more frequent the presence of edemas (10/18 vs. 2/25, p=0.001). CONCLUSION: The present clinical study confirmed the benefit of retrograde tibial tunnel drilling for tibial subchondral bone lesions and showed a correlation between these lesions and early postoperative pain. LEVEL OF EVIDENCE: II; therapeutic study - prospective cohort study.