Signal intensity of lateral meniscal allografts deteriorates over time: a longitudinal MRI analysis during a minimum follow-up of 8 years

Abstract

Purpose To evaluate the serial change of magnetic resonance imaging (MRI) signal intensity (SI) of lateral meniscal allografts in a long-term period of > 8 years and to determine whether the SI change adversely afected clinical outcomes. Methods Thirty-three lateral meniscal allograft transplantation (LMAT) patients with MRI taken > 8 years after surgery were included. The allograft was assessed using MRI at ive serial time points (1, 2-4, 4-6, 6-8, and > 8 years after surgery), based on the following grading system: grade 1, globular increased SI not adjacent to the articular surface; grade 2, linear SI within the meniscus; and grade 3, increased SI extended to the articular surface. MRI evaluation was performed for three locations of the allograft (anterior horn, mid-body, and posterior horn), and the serial changes of allograft SI at each location were analyzed using the generalized estimating equation (GEE) with cumulative logit link function. The patients were classiied according to SI change at each location (stationary group and deterioration group), and the two groups were compared in terms of clinical outcomes using the Lysholm score. ResultsThe mean follow-up duration was 9.2 ± 1.2 years. During that period, SI of the allograft deteriorated over time, regardless of the location (anterior horn, p = 0.034; mid-body, p = 0.002; posterior horn, p < 0.001). The amount of SI deterioration at each location of the graft difered with a borderline signiicance (p = 0.050, GEE), and the proportion of grade 3 SI was higher at the posterior horn (36.4%) than at the other locations at the last follow-up (p < 0.001, chi-square test). However, no signiicant diferences in the Lysholm scores were found between the stationary group and the deterioration group at all locations. Conclusion SI of the meniscal allograft deteriorated over time at all locations during the long-term follow-up. Deterioration of the graft was more prominent at the posterior horn than at the other locations. SI deterioration did not adversely afect the clinical outcomes, which should be interpreted with caution, considering the small sample size of this study. In the prognosis of lateral MAT, SI deterioration at the posterior horn is a more determining factor than that at the other part of the allograft. Therefore, SI at the posterior horn needs to be examined with special concern. Level of evidence III.

Risk Factor for Clinical Failure of Medial Meniscal Allograft Transplant: Early vs Late Graft Tear

“…The indications for medial MAT were (1) physically active patients, (2) subtotal or total meniscectomized state, (3) localized medial knee pain that was persistent despite nonoperative treatments, and (4) preserved joint space ≥2 mm on Rosenberg view radiographs. 4,9,27 Based on the cartilage wear of the medial compartment, which was evaluated intraoperatively, International Cartilage Regeneration & Joint Preservation Society (ICRS) grade ≤3 and localized grade 4 lesions in the area that could be covered by the allograft were considered acceptable for MAT. When varus malalignment or instability of the joint was present, realignment osteotomy or ligament reconstruction was performed before or during the index surgery.…”

Early Graft Tear As a Major Risk Factor for the Clinical Failure of Lateral Meniscal Allograft Transplantation

“…Lateral MAT was considered for patients who (1) were physically active, (2) had a history of subtotal or total lateral meniscectomy, and (3) had persistent localized pain in the lateral compartment. 3,5,20 Radiography in the Rosenberg view was performed preoperatively to check for a minimum preserved joint space of 2 mm. Any valgus alignment or instability of the joint was corrected with distal femoral osteotomy before or during index surgery.…”

Total meniscus replacement with a 3D printing of network hydrogel composite scaffold in a rabbit model

“…Antibiotic prophylaxis was administered preoperatively through intramuscular injection of penicillin (400,000 U) (HyClone). The samples were implanted as previously described [1,2,4,16,26,32] (Figure 1a-d).…”

“…Since the risk of developing postoperative osteoarthritis (OA) after meniscectomy (Meni) depends on the proportion of meniscus left after surgery, patients who undergo partial Meni are usually at high risk of developing OA of the knee [11,24], while patients who undergo total Meni are most likely to develop OA of the knee [22,24]. Although meniscal allografts can effectively delay the degenerative process [26,29], allografts are associated with poor long-term results, rejection reactions, risk of disease transmission and insufficient donor sources [3,12,30]. As a result, the focus has shifted to the potential application of artificial meniscus grafts to overcome these challenges.…”