Functional, Magnetic Resonance Imaging, and Second-Look Arthroscopic Outcomes After Pullout Repair for Avulsion Tears of the Posterior Lateral Meniscus Root

Abstract

Background: Little data exist in the literature regarding second-look arthroscopic outcomes after pullout repair for avulsion tears of the posterior lateral meniscus root. Purpose: To (1) assess the functional, magnetic resonance imaging (MRI), and second-look arthroscopic outcomes after pullout repair for avulsion tears of the posterior lateral meniscus root; (2) determine which demographic and clinical factors influenced healing of the repaired posterior lateral meniscus root; and (3) compare outcomes between different meniscal healing status groups. Study Design: Case series; Level of evidence, 4. Methods: A total of 31 patients underwent pullout repair for avulsion tears of the posterior lateral meniscus root and had a minimum 2-year follow-up. Functional outcomes were assessed using patient-reported scores (Lysholm, Tegner, and International Knee Documentation Committee [IKDC] scores). Lateral meniscal extrusion, cartilage degeneration of the lateral compartment, and healing of the repaired posterior lateral meniscus root were assessed via MRI. The healing status was also assessed using second-look arthroscopic surgery, and the patients were divided into different healing status groups. Results: The postoperative patient-reported scores improved significantly compared with the preoperative values ( P = .001). Lateral meniscal extrusion was reduced significantly from 3.37 ± 0.82 mm preoperatively to 0.63 ± 0.80 mm at final follow-up ( P = .001). The grade of cartilage degeneration of the lateral compartment progressed from 0.69 ± 0.67 preoperatively to 0.95 ± 0.83 at final follow-up ( P = .213). MRI scans showed complete healing in 28 patients (90.3%) and partial healing in 3 patients (9.7%). Second-look arthroscopic surgery showed stable healing in 18 of 23 patients (78.3%) and lax healing in 5 of 23 patients (21.7%). Patients with stable healing had significantly higher Lysholm and IKDC scores, more reduction of meniscal extrusion, and less progression of cartilage degeneration than did patients with lax healing ( P < .05). Concomitant anterior cruciate ligament reconstruction was found to significantly positively influence healing of the repaired posterior lateral meniscus root ( P = .047). Conclusion: Pullout repair for avulsion tears of the posterior lateral meniscus root yielded significantly improved patient-reported scores, reduced meniscal extrusion, and a satisfactory healing rate at final follow-up. Patients with stable healing had significantly better functional and MRI outcomes than did patients with lax healing.

Association Between Transtibial Meniscus Root Repair and Rate of Meniscal Healing and Extrusion on Postoperative Magnetic Resonance Imaging: A Prospective Multicenter Study

“… 23 The technique for assessing healing of meniscus root repairs and extrusion has been well established, and previous literature on interobserver reliability assessments has shown rates of ≥0.90. 5 , 45 The femoral condyles and tibial plateau articular cartilage surfaces were evaluated and graded using the modified Outerbridge classification system. 41 , 26 MRI scans were also assessed for coronary/meniscotibial ligament abnormalities, subchondral cysts, subchondral edema, insufficiency fractures, and subchondral collapse using the Whole-Organ Magnetic Resonance Imaging Score.…”

Quantifying the differential functional behavior between the medial and lateral meniscus after posterior meniscus root tears

“…For example, after medial meniscus repair, MRI evaluation has demonstrated continued meniscus extrusion [ 24 ] and low healing rates [ 25 ]. Similarly, the paucity of research regarding the clinical implications of PRTs of the lateral meniscus demonstrates lax healing of up to 21% [ 26 ], and a recent systematic review was unable to conclude whether root repair restored the functional hoop stress characteristics required of the meniscus to distribute compression forces across the knee evenly [ 27 ]. Furthermore, a recent study found characteristic clinical differences between the medial and lateral meniscus PRTs, including the association of trauma in lateral meniscus PRTs, and older age and higher grade of OA changes of the knee in medial meniscus PRTs [ 1 ].…”

Prospective Consecutive Clinical Outcomes After Transtibial Root Repair for Posterior Meniscal Root Tears: A Multicenter Study

“…Moon et al 22 demonstrated that patients with progressive medial meniscal extrusion after surgery had significantly worse KL grades at 2 years postoperatively. In addition, Zhuo et al 31 reported a significant linear relationship between postoperative lateral meniscal extrusion and progression of cartilage generation at an average 29.9-month follow-up. While meniscal extrusion was not correlated with poor IKDC scores, the present study suggests that overall patients with extrusion may decrease activity level, perhaps to accommodate symptoms.…”

“… 11 The technique for assessing healing of meniscal root repairs and extrusion has been well established, and previous literature on interobserver reliability assessments have been at least 0.90. 31 The femoral condyles and tibial plateau articular cartilage surfaces were evaluated and graded using the modified Outerbridge classification system. 14 The postoperative MRI results have been published and were used for correlation of clinical outcomes in the current study.…”

“… 20 In addition, clinical outcome studies show increased healing on magnetic resonance imaging (MRI) and second-look arthroscopy. 1 , 7 , 18 , 20 , 23 – 25 , 31 However, transtibial root repair research has focused on the medial meniscus, thus limiting the complete assessment of posterior root tears. There is also a lack of prospective data correlating preoperative and early postoperative radiographic findings with patient-reported outcomes, particularly in patients with an elevated body mass index (BMI).…”