Medial meniscus posterior root tear induces pathological posterior extrusion of the meniscus in the knee-flexed position: An open magnetic resonance imaging analysis

Okazaki

et al. 2019

Knee Surg & Relat Res

Purpose: Posterior root repair of the medial meniscus (MM) can prevent rapid progression of knee osteoarthritis in patients with a MM posterior root tear (MMPRT). The anatomic reattachment of the MM posterior root is considered to be critical in a transtibial pullout repair. However, tibial tunnel creation at the anatomic attachment is technically difficult. We hypothesized that a newly developed point-contact aiming guide [Unicorn Meniscal Root (UMR) guide] can create the tibial tunnel at a better position rather than a previously designed MMPRT guide. The aim of this study was to compare the position of the created tibial tunnel between the two meniscal root repair guides. Materials and methods: Thirty-eight patients underwent transtibial pullout repairs. Tibial tunnel creation was performed using the UMR guide (19 cases) or MMPRT guide (19 cases). Three-dimensional computed tomography images of the tibial surface were evaluated using the Tsukada's measurement method postoperatively. The expected anatomic center of the MM posterior root attachment was defined as the center of three tangential lines referring to three anatomic bony landmarks (anterior border of the posterior cruciate ligament, lateral margin of the medial tibial plateau, and retro-eminence ridge). The expected anatomic center and tibial tunnel center were evaluated using the percentage-based posterolateral location on the tibial surface. The distance between the anatomic center and tunnel center was calculated. Results: The anatomic center of the MM posterior root footprint was located at a position of 79.2% posterior and 39.5% lateral. The mean of the tunnel center in the UMR guide was similar to that in the MMPRT guide (posterior direction, P = 0.096; lateral direction, P = 0.280). The mean distances between the tunnel center and the anatomic center were 4.06 and 3.99 mm in the UMR and MMPRT guide group, respectively (P = 0.455). Conclusions: The UMR guide, as well as the MMPRT guide, is a useful device to create favorable tibial tunnels at the MM posterior root attachment for pullout repairs in patients with MMPRTs.

Section: Methodsmentioning

confidence: 99%

The accuracy of a newly developed guide system in medial meniscus posterior root repair: a comparison between two aiming guides

Okazaki

et al. 2019

Knee Surg & Relat Res

“…An open MRI analysis found that MMPRT caused pathological posterior extrusion of the MM medial and posterior segment at 90° knee flexion [23,24]. Therefore, analysis of MM medial/posterior extrusion (MMME/MMPE) in older patients after transtibial fixation of MMPRT using open MRI is clinically useful in assessing MM conditions, especially at 90° knee flexion.…”

Section: Introductionmentioning

confidence: 99%

Transtibial fixation for medial meniscus posterior root tear reduces posterior extrusion and physiological translation of the medial meniscus in middle-aged and elderly patients

Knee Surg Sports Traumatol Arthrosc

Masuda

et al. 2019

Purpose: To investigate changes in meniscal extrusion during knee flexion before and after pullout fixation for medial meniscus posterior root tears (MMPRTs) and determine whether these changes correlate with articular cartilage degeneration and short-term clinical outcomes. Methods: Twenty-two patients (mean age, 58.4±8.2 years) diagnosed with type II MMPRT underwent open MRI preoperatively, 3-months after transtibial fixation, and at 12-months after surgery, when second-look arthroscopy was also performed. The medial meniscus (MM) medial and posterior extrusion (MMME and MMPE) were measured at knee 10° and 90° flexion; at which MM posterior translation was also calculated. Articular cartilage degeneration was assessed using ICRS grade at primary surgery and second-look arthroscopy. Clinical evaluations included Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee subjective knee evaluation form, Lysholm score, Tegner activity level scale, and visual analog scale. Results: MMME at 10˚ knee flexion was higher 12 months postoperatively than preoperatively (4.77±1.48 vs. 3.53±1.17, p=0.012). MMPE at 90˚ knee flexion and MM posterior translation were smaller 12 months postoperatively than preoperatively (3.49±1.05 vs. 4.60±1.27, 7.23±1.74 vs. 8.89±1.98, p<0.001). Articular cartilage degeneration of medial femoral condyle correlated with 2 MMME in knee extension (r=0.48, p=0.04). All clinical scores significantly improved 12 months postoperatively; however, correlations of all clinical scores against decreased MMPE and increased MMME were not detected. Conclusions: MMPRT transtibial fixation suppressed the progression of MMPE and cartilage degeneration and progressed MMME minimally in knee flexion position at one-year. However, in the knee extension position, MMME progressed and correlated with MFC cartilage degeneration.

“…Because of this effect of tibiofemoral subluxation on the mechanics of the medial knee compartment, tibiofemoral subluxation may increase the incidence of intercondylar notch and tibial eminence impingement. Considering that the medial meniscus (MM) plays a role as a secondary stabilizer during tibial translation [8], with a posterior root tear, the MM is displaced medially and posteriorly [2,9]. This displacement may induce pathological movements at the knee joint, including a tibiofemoral subluxation.…”

Section: Introductionmentioning

confidence: 99%

Preliminary diagnosis of medial meniscus posterior root tears using the Rosenberg radiographic view

Kamatsuki

et al. 2019

Knee Surg & Relat Res

Purpose: To verify the effectiveness of detecting medial meniscus posterior root tears (MMPRTs) using weightbearing posterior-anterior (PA) radiographs. Materials and methods: Twenty-three patients were diagnosed with an MMPRT using magnetic resonance imaging (Group A), with 23 matched individuals forming the control group (Group B). The distance between medial tibial eminence and the lateral edge of the medial femoral condyle (MTE-MFC distance) and medial joint space (MJS) width were measured on weight-bearing PA radiographs, with the knee flexed at 45°(Rosenberg view). Absolute medial meniscus extrusion (MME) was measured on magnetic resonance images. Results: The MTE-MFC distance was greater and the MJS width was smaller in Group A than Group B (7.7 ± 1.7 mm versus 6.0 ± 1.24 mm and 3.2 ± 0.8 mm versus 4.5 ± 0.7 mm, respectively; P < 0.05). The MTE-MFC distance and MJS width correlated with MME (r = 0.603 and 0.579, respectively; P < 0.05), and the extent of MME was greater in Group A than Group B (4.1 ± 1.1 mm versus 1.8 ± 1.5 mm, respectively; P < 0.05). Conclusions: MMPRTs increase the MTE-MFC distance and decrease the MJS width, with these measurements correlating to the MME. Therefore, measurement of the MTE-MFC distance and MJS width on the Rosenberg view could be a useful preliminary method for the diagnosis of an MMPRT.