Vertical Tears of the Lateral Meniscus

Abstract

Background:Lateral meniscal tears are often seen with acute anterior cruciate ligament (ACL) injury and may be left in situ, repaired, or treated with meniscectomy. Clinical studies have shown good outcomes with vertical tears left in situ and poor outcomes following meniscectomy. However, clinically relevant studies are needed to establish a biomechanical foundation for treatment of these tears, particularly regarding the effects of meniscectomy.Purpose:To compare tibiofemoral joint mechanics following vertical lateral meniscal tears and meniscectomies. We hypothesized that a peripheral vertical tear of the lateral meniscus would alter joint mechanics, increasing contact pressure and area, and that more drastic effects would be seen following meniscectomy, at higher knee flexion angles, and with increased loads.Study Design:Controlled laboratory study.Methods:Ten fresh-frozen cadaveric knees (average age, 55 ± 12 years) were tested with 5 lateral meniscus states: intact, short vertical tear, extended vertical tear, posterior horn partial meniscectomy (rim intact), and posterior horn subtotal meniscectomy (rim excised). The specimens were loaded axially at knee flexion angles of 0°, 30°, and 60°, and musculotendinous forces were applied, simulating a 2-legged squat. Intra-articular contact pressures were measured using pressure-sensitive Fuji film. Kinematic data were acquired through digitization of fiducial markers.Results:Vertical tears did not cause a significant change in contact pressure or area. Partial meniscectomy increased maximum contact pressures in the lateral compartment at 30° and 60° from 5.3 MPa to 7.2 MPa and 7.6 MPa, respectively (P = .02, P = .007). Subtotal meniscectomy (8.4 MPa) significantly increased contact pressure compared with partial meniscectomy (7.6 MPa) at 60° (P = .04). Both meniscectomy states significantly increased contact pressures with increasing flexion from 0° to 60° (P < .001, P < .001).Conclusion:Vertical tears of the lateral meniscus during a simulated 2-legged squat did not significantly change contact pressures and areas compared with an intact meniscus. However, treating these tears with partial and complete meniscectomy significantly increased maximum contact pressures.Clinical Relevance:Biomechanical evidence supports treating vertical lateral meniscus tears with meniscal-sparing techniques as opposed to meniscectomy, which may lead to progressive degenerative joint disease from altered joint biomechanics.

Biomechanical Forces of the Lateral Knee Joint Following Meniscectomy and Meniscus Transplantation in Pediatric Cadavers

“…These findings are consistent with observations in adult cadavers. 12,13 While the inverse relationship between increasing flexion and CA is similar to findings in adult cadavers, Goyal et al 14 found no differences between intact and meniscectomy states at 60°. In comparison, we observed notable differences between intact and meniscectomy states at 60° as well as between intact and transplant states.…”

“…Relative to the intact state, meniscectomy was associated with decreased mean CA and increased CP, similar to reports in adults. 12-14 Differences between the transplant state and the intact state were not statistically significant at all degrees of flexion, except CA at 0° and peak pressure at 30°. Pairwise comparisons between meniscus states show that while peak pressure remained elevated after transplant, average pressure and CA improved toward intact state values.…”

“…Our observations of increasing peak pressure with flexion are similar to observations in adult cadavers after total meniscectomy. 14 Elevated pressures at increasing degrees of flexion may be because of a less congruent articular surface and greater degree of medial translation of the lateral compartment in total meniscectomy. 15 The cadaveric study by Novaretti et al 15 found that suture-only and bone block meniscus allograft transplants similarly improved medial translation to 50 to 60% of the intact lateral meniscus in the condition of anterior tibial load and axial compression, but neither meniscus transplant technique improved medial translation in response to valgus and internal tibial or external tibial torques.…”

Meniscal Allograft Transplantation

“…5 Regardless of tear pattern, it is preferred to maintain as much native meniscal tissue as reasonable as even partial meniscectomies result in altered biomechanics of the tibiofemoral articulations and lead to increased contact pressures on the articular cartilage. 1,2,[5][6][7][8][9] The increase in contact stresses across the joint has been shown to be proportional to the percentage of the meniscus that is removed. 2 These findings indicate that a diminished or absent meniscus can cause increased degeneration of the articular cartilage in the involved compartment, which is consistent with multiple studies that have demonstrated an increased risk of osteoarthritis in the setting of a knee with the deficient or absent meniscus.…”

Meniscus tears treatment: The good, the bad and the ugly-patterns classification and practical guide

“…Small stable longitudinal tears (both partial and full thickness tears), as well as small oblique/flap tears can be classified as good lesions. This is mainly due to the poor impact on knee biomechanics[ 10 ], both in terms of maximum contact pressure and tibial contact area changes. However, if the tear is more than 15 mm and involves the posterior horn of the meniscus, a significant change of knee biomechanics has been reported[ 47 ].…”