A Balanced Arthroscopic Debridement of the Inner Layer of the Knee Retinaculum Increases the Tibiofemoral Joint Space Width.

INTRODUCTION: Traditional techniques can enlarge the medial tibiofemoral joint space width (JSW) for meniscal repairs, but a remnant ligament laxity may be developed. Alternatively, the debridement of the inner retinaculum layer may result in a balanced JSW without causing extra-ligament damage (retinaculum layers II and collateral ligament). PURPOSE: The purpose of this study was to determine whether a concentric arthroscopic debridement of the inner retinaculum layer increases the tibiofemoral JSW in patients with meniscal injuries. Secondarily, we determine whether the increase in JSW is symmetrical between compartments and describe the rate of complications and patient satisfaction. METHOD: Twenty middle-aged (15 male and five female) patients diagnosed with acute meniscal injury aged 36 ± 12 years were enrolled. The patients were submitted to an arthroscopic debridement of the inner layer of the knee retinaculum for both the medial and lateral compartments. The tibiofemoral JSW was measured intra-articularly using a custom instrument. A two-way ANOVA for repeated measures was used to compare the JSW. A Bland-Altman analysis and test-retest analysis were performed. RESULTS: The JSW increased following the debridement of the inner retinaculum layer, for both the medial and lateral compartments (p < 0.001). No complications were identified, and the patients were satisfied with the intervention. The minimal detectable change and bias of the custom instrument were 0.06 mm and 0.02 mm, respectively. CONCLUSION: The debridement allows a clinically important (>1 mm) symmetric tibiofemoral JSW enlargement. The technique suggests favoring the diagnosis of meniscus injuries and manipulating arthroscopic instruments without secondary complications after one year.

Validity of the Genourob arthrometer in the evaluation of total thickness tears of anterior cruciate ligament.

OBJECTIVE: Our purpose was to evaluate the validity and reliability of the laxity with the GNRB arthrometer in subjects with anterior cruciate ligament injury. MATERIAL AND METHOD: A diagnostic study was performed by three operators using the Genourob arthrometer, measuring the displacement of the anterior cruciate ligament. The concordance was assessed by the intraclass correlation coefficient mixed effects model, Lin correlation coefficient and graphic method from Bland-Altman. Using the anterior cruciate ligament tear as a dependent variable and the Genourob measurement as an independent variable, a logistic regression was determined. RESULTS: Obtaining the complete information of 157 knees. The measurements with the Genourob arthrometer distributed symmetrically, with mean ± standard deviation of knees with anterior cruciate ligament injury: 5.64 ± 1.72 and knees without anterior cruciate ligament injury: 3.29 ± 1.72. The ICCs as well as the LCCs were equal to or greater than 0.99. The BA showed discrepancy for a pair of observations no greater than 7.64%. The odds ratio of the knee displacement measurement for the presence of anterior cruciate ligament injury was 4.04 (95% CI: 2.59-6.32; p-value < .01) with a ROC area of 0.863 (95% CI: 0.789-0.9456). The cut-off point of the anteroposterior knee displacement located at 6.8 mm determined a sensitivity of 74.4% and specificity of 93.8%, with a Youden Index = 0.67. CONCLUSION: The Genourob arthrometer is reliable and valid to establish where laxity values correlate with total thickness tears of the anterior cruciate ligament.