Is meniscal allograft transplantation chondroprotective? A systematic review of radiological outcomes

Addressing meniscal deficiency part 1: An umbrella review of systematic reviews and meta-analyses on meniscal allograft transplantation

Purpose

Meniscal injuries are common in the young and active population. There is increasing utilization of surgical interventions like meniscal allograft transplantation (MAT) to restore the protective function of menisci following injury leading to meniscal deficiency. Extensive research and publications exist on the management of meniscal injury and the sequalae of meniscal deficiency. However, a comprehensive synthesis of the existing evidence through an umbrella review is lacking. This study aims to fill this gap by providing a current examination of the literature on MAT.

Methods

A comprehensive search was conducted in the MEDLINE, Embase and Scopus databases to identify relevant systematic reviews and meta-analyses. Studies were screened based on predefined inclusion and exclusion criteria. The quality of the included studies was assessed using the AMSTAR-2 tool.

Results

A total of 41 studies were included in the review, with most published within the last decade. The majority of studies (56.1%) received a 'Critically Low' confidence rating, 26.8% were rated as 'Low', and only 14.6% were rated as 'High' confidence. From the included studies, 51.2% reported on PROMs, with the Lysholm score being the most common. Transplant failure and reoperation rate were reported in 34.1% and 19.5% of studies respectively. Studies on MAT reported favourable short-term outcomes in terms of patient-reported outcome measures (PROMs) but were limited by the lack of randomized control trials and consistent comparison groups.

Conclusions

This umbrella review highlights an increase in interest in MAT but underscores the need for higher-quality reviews with standardized reporting and rigorous methodologies. Future research should focus on long-term outcomes, optimal surgical techniques, patient selection criteria and risk factors for transplant failure. There is also a need for more studies focusing on MAT in pediatric populations. Overall, this review provides a comprehensive assessment of the current state of research in MAT and identifies areas for improvement in future studies.

Level of Evidence

Level IV.

Trends in utilization of meniscal allograft transplantation between 2010 and 2019

OBJECTIVES

The aim of this study was to observe the trends in (1) utilization of meniscus allograft transplantation (MAT), (2) demographics and comorbidities of patients undergoing transplants and (3) reimbursements for this procedure between the years of 2010 and 2019.

METHODS

Using a national database, patients who underwent MAT were observed. Incidence of MAT, percentage of female patients, average age, and average Charlson comorbidity index (CCI) were analyzed between 2010 and 2019. Average reimbursement during the index and postoperative 90-day bundle period were also calculated from 2010 to 2019. Compound annual growth rate (CAGR) of change in incidence, demographic and reimbursement was calculated, and linear regressionwas conducted for each trends analysis.

RESULTS

In total, 744 patients underwent a MAT between the years of 2010 and 2019. The incidence of MAT increased from 0.12 per 100,000 to 0.15 per 100,000 during this period but was not statistically significant (p=0.345). There was no significant difference in age (p=0.462) and gender (p=0.831) among the patients, but the average CCI significantly increased from 2010 to 2019 (CAGR: +15.30; p=0.001). The total reimbursement in the index (p=0.451) and 90-day bundle period (p=0.191) did not significantly change from 2010 to 2019.

CONCLUSIONS

Although MAT has been shown to be a safe and reliable surgery for the treatment of meniscus deficient knees, the incidence of MAT as well as the population undergoing MAT has minimally increased from 2010 to 2019. Future studies should seek to identify why the utilization of this efficacious surgery has not increased.

LEVEL OF EVIDENCE

IV; Descriptive Epidemiology Study.

Efficacy of Intraoperative Platelet-Rich Plasma After Meniscal Repair: Systematic Review and Meta-analysis

Background

Meniscal injuries frequently require surgical intervention to restore knee joint function and stability. Intraoperative platelet-rich plasma (PRP) injection has emerged as a potential adjunctive therapy to enhance tissue healing post-meniscal repair. This systematic review and meta-analysis aimed to evaluate the efficacy of PRP in terms of pain relief, functional recovery, and overall success rates in patients undergoing meniscal repair procedures.

Methods

A comprehensive search strategy was employed to identify relevant studies across Scopus, PubMed, Embase, and the Cochrane Library databases. The inclusion criteria encompassed human studies, including randomized controlled trials (RCTs), cohorts, and case-control studies, focusing on intraoperative platelet-rich plasma (PRP) use post-meniscal repair and reporting outcomes related to pain, functionality, and cure rates. Exclusion criteria comprised animal studies, non-English publications, studies lacking relevant outcome measures, and those with insufficient data. Two reviewers independently screened titles and abstracts, resolving disagreements through consensus or consultation with a third reviewer, followed by a full-text assessment for potentially eligible studies. Data extraction was conducted independently by two reviewers using a standardized form. The reliability of observational studies was evaluated using the Newcastle-Ottawa Scale. Subgroup analyses and pooled effect estimates for main outcomes were computed using RevMan 5.3, a meta-analysis tool.

Results

The demographic analysis revealed that the PRP group had an average age of 41.39 years, while the control group had an average age of 42.1 years. In terms of gender distribution, the PRP group consisted of 61 men and 29 women, while the control group had 62 men and 34 women. Pain ratings showed a preference for PRP with a mean difference of 4.83 (p = 0.13). However, there was no significant difference in Lysholm scores (mean difference: - 0.44, p = 0.91) or IKDC scores (mean difference: 2.80, p = 0.14) between the PRP and control groups. Similarly, ROM measures did not show a statistically significant difference, with a mean difference of 2.80 (p = 0.18). Additionally, there was no significant distinction in failure rates between the PRP and control groups, as indicated by a weighted mean difference of 0.71 (p = 0.52). These findings suggest that while PRP may offer some benefits in pain relief, its impact on functional recovery, range of motion, and failure rates following meniscal repair procedures is inconclusive.

Conclusion

The current evidence regarding the effect of intraoperative platelet-rich plasma (PRP) injection on patients undergoing meniscal repair remains inconclusive. While some studies suggest potential benefits in terms of pain relief and functional recovery, others show no significant differences compared to control groups. The impact of PRP therapy on overall success rates, including rates of re-tear and revision surgery, is also uncertain. Further well-designed randomized controlled trials with larger sample sizes are needed to provide more robust evidence and guide clinical practice in orthopedic surgery.

Clinical and Radiological Outcomes of Medial Meniscal Allograft Transplantation Combined With Realignment Surgery

BACKGROUND

The outcomes of medial meniscal allograft transplantation (MMAT) combined with high tibial osteotomy (HTO) compared with isolated MMAT remain unclear.

PURPOSE

To compare the clinical and radiological results of MMAT combined with HTO and isolated MMAT.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective study included 42 consecutive patients, who were divided into group M (isolated MMAT; n = 22) and group H (MMAT combined with HTO with a varus angle >3°; n = 20). Group differences in subjective knee scores, isokinetic muscle strength test, and radiological outcomes (Kellgren-Lawrence grade, mechanical axis, graft extrusion, graft status, and articular cartilage loss) were compared.

RESULTS

The mean follow-up period was 29.2 ± 4.9 months and 27.4 ± 5.3 months for groups M and H, respectively. The Lysholm score improved from 55.4 ± 9.5 to 81.3 ± 9.7 and from 52.6 ± 8.9 to 84.2 ± 10.2 in groups M and H, respectively (both P < .001). The International Knee Documentation Committee subjective score improved from 51.4 ± 10.3 to 79.6 ± 9.4 and from 49.3 ± 11.4 to 81.4 ± 8.3 in groups M and H, respectively (both P < .001). Both groups showed no significant differences in subjective knee scores and isokinetic extensor strength at the final follow-up. The rate of preoperative and postoperative high International Cartilage Regeneration & Joint Preservation Society grade (≥3) did not differ between the 2 groups. Group M showed greater coronal graft extrusion than did group H (3.3 ± 0.7 mm vs 2.7 ± 0.8 mm; P = .014); the rate of pathologic graft extrusion (≥3 mm) was not higher in group M (40.9%) than in group H (20%) with the number of patients available (P = .143). Both groups showed no significant difference in the graft status. Graft tears were observed in 2 patients (9%) in group M and 1 patient (5%) in group H (P = .607).

CONCLUSION

Clinical scores significantly improved after isolated MMAT and MMAT combined with HTO compared with preoperative values, and their short-term outcomes were similar. Postoperative graft extrusion was greater in patients who underwent isolated MMAT, implying that active correction of varus alignment during MMAT may help in intra-articular biomechanics.

10-Year Survival and Clinical Improvement of Meniscal Allograft Transplantation in Early to Moderate Knee Osteoarthritis

BACKGROUND

Meniscal allograft transplantation (MAT) is a viable option for patients experiencing unicompartmental knee pain after total or subtotal meniscectomy. Nonetheless, caution is recommended when suggesting this procedure in the presence of knee osteoarthritis (OA) because of the higher risk of poor survival and outcomes.

PURPOSE/HYPOTHESIS

The purpose was to document the long-term survival of MAT performed as a salvage procedure in patients with knee OA. The hypothesis was that MAT would significantly reduce pain and increase the function of the affected joint at a long-term follow-up compared with the preoperative condition, with a low number of failures and knee replacement surgeries.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 47 patients (37 men and 10 women) with symptomatic knee OA (Kellgren-Lawrence grades 2 or 3) treated with MAT were evaluated at baseline, 5 years, and a minimum 10-year final follow-up (11.1 ± 1 years) using the Lysholm score, the visual analog scale for pain, the Knee injury and Osteoarthritis Outcome Score subscales, and the Tegner score. A total of 44 patients had undergone previous surgeries. Patient satisfaction, revision surgeries, and failures were also recorded.

RESULTS

A statistically significant improvement was observed in all clinical scores from the baseline assessment to the final follow-up. The Lysholm score improved significantly from 46.4 ± 17.2 at the preoperative assessment to 77.7 ± 20.4 at the intermediate follow-up (P < .001), with a significant decrease at the final follow-up (71 ± 23.3; P = .018). A similar trend was reported for the visual analog scale scale for pain, Knee injury and Osteoarthritis Outcome Score, and Tegner score, with no complete recovery to the previous sports activity level. A total of 33 patients required concurrent procedures, such as anterior cruciate ligament reconstructions, osteotomies, and cartilage procedures. Five patients underwent reoperation and were considered surgical failures, while 15 patients presented a clinical condition of <65 of the Lysholm score and were considered clinical failures. Among these, 4 patients were considered both surgical and clinical failures.

CONCLUSION

MAT surgery has proven to be a valid option for improving pain and function even in OA joints (Kellgren-Lawrence grades 2 or 3), yielding satisfactory results despite a worsening clinical outcome in the long-term follow-up. Therefore, based on the data from this study, orthopaedic surgeons may consider recommending MAT as a salvage procedure even in knees affected by early to moderate OA, while advising patients that the need for combined interventions could potentially reduce graft survival.

Meniscal Repair With Iliotibial Band Grafting and Collagen Membrane Wrapping Augmentation

This work contains a description of the modified Henning operation. This technique can be proven especially useful in difficult cases of damaged meniscus (complex injuries). It consists of three stages: stable suturing of the meniscus, placement of the graft from the iliotibial band on the meniscus, and covering the graft with a collagen membrane. Stitching the meniscus provides initial stabilization, the graft from the iliotibial band provides scaffolding for the reconstructed tissue, and the collagen membrane provides biological stimulation for healing.

Unicompartmental osteoarthritis: High survival rate with a combined mechanical and biological salvage approach as alternative to metal resurfacing: Results at minimum 10 years of follow-up

PURPOSE

The aim of this study was to prospectively evaluate the long-term clinical results and failure rate of patients treated with complex salvage procedures using a combined mechanical and biological approach to address unicompartmental knee osteoarthritis (OA) and postpone the need for joint replacement.

METHODS

Thirty-nine patients (40.3 ± 10.9 years old) affected by unicompartmental OA (Kellgren-Lawrence 3) in stable joints underwent a personalized surgical treatment depending on the specific requirements of the affected compartment, including high tibial osteotomy, osteochondral scaffold, meniscal scaffold and meniscal allograft transplantation. Patients were evaluated with the International Knee Documentation Committee (IKDC), Visual Analogue Scale (VAS) and Tegner scores before surgery, at 3 years and a minimum of 10 years of follow-up.

RESULTS

A significant improvement was observed over time in all scores but worsened at the final follow-up. The IKDC subjective score improved from 46.9 ± 16.2 to 79.8 ± 16.4 at 3 years (p < 0.0005) and then decreased to 64.5 ± 21.4 (p = 0.001) at 12 years. A similar trend was confirmed for VAS and Tegner scores. Only two patients subsequently underwent knee arthroplasty, and nine more patients were considered clinical failure, for a cumulative surgical and clinical failure rate of 28.2% at the final follow-up.

CONCLUSION

A personalized, joint-preserving, combined mechanical and biological approach, addressing alignment as well as meniscal and cartilage lesions, is safe and effective, providing a clinical benefit and delaying the need for arthroplasty in young patients affected by unicompartmental knee OA. At the final evaluation, the clinical improvement decreased, but more than two-thirds of the patients still benefited from this treatment at a long-term follow-up.

LEVEL OF EVIDENCE

Level IV case series.

Lateral Meniscal Allograft Transplantation Shows a Long-Term Chondroprotective Effect on Quantitative Magnetic Resonance Imaging T2 Mapping at 7-Year Minimum Follow-Up

PURPOSE

To assess the long-term chondroprotective effect of lateral meniscal allograft transplantation (MAT) using quantitative magnetic resonance imaging (MRI) T2 mapping.

METHODS

In patients who underwent isolated lateral MAT, quantitative MRI T2 mapping was conducted preoperatively and postoperatively with at minimum follow-up of 7 years to assess the articular cartilage status. On the sagittal section image bisecting the lateral femoral condyle, the weight-bearing portions of the femoral and tibial articular cartilage were divided into 3 segments each-6 segments in total-based on the meniscal coverage area. The regions-of-interest analyses were performed on the 6 segments to measure the mean T2 value. Then the whole layer was divided into deep and superficial layers for further zonal analysis. The longitudinal change in T2 values was statistically analyzed using paired t-tests. Clinical outcome was evaluated using the Lysholm score.

RESULTS

A total of 31 patients were included in the study, with the MRI follow-up period of a minimum of 7 years (mean: 8.9 ± 1.3 years; range: 7.0-11.2 years). The mean T2 value of the whole layer showed significant improvement in all segments of the femoral cartilage and the posterior segment of tibial cartilage. In the zonal analysis, the mean T2 value of the tibial cartilage showed significant improvement in the superficial layer of the mid to posterior portion, while the deep layer remained stable. In contrast, the mean T2 value of the femoral cartilage showed significant improvement in the superficial and deep layers in all segments. The mean Lysholm score significantly improved from 62.6 ± 12.8 to 90.9 ± 10.5 (P < .001).

CONCLUSIONS

This study suggests that MAT appears to have a long-term chondroprotective effect on the articular cartilage as judged by quantitative T2 mapping.

LEVEL OF EVIDENCE

Level Ⅳ, case series.

Editorial Commentary: Meniscal Allograft Transplantation Results in Both Pain Relief and Chondroprotection

Meniscal allograft transplantation (MAT) effectively alleviates symptoms of the meniscus deficiency. Thus, MAT is a widely accepted and recommended treatment for individuals with unicompartmental pain due to meniscus deficiency. Long-term follow-up studies have indicated that MAT yields favorable clinical outcomes, demonstrating high survivorship and low rates of serious complications. In addition, the ability of MAT to function akin to the native meniscus and shield the knee cartilage from osteoarthritis has been a subject of ongoing investigation, and recent direct magnetic resonance imaging evidence shows long-term chondroprotection following MAT. Cartilage lesions worsen during the meniscus deficiency period. Consequently, delaying MAT until patients become more symptomatic may lead to poor outcomes and low graft survivorship due to concomitant cartilage lesions. These findings prompt a reevaluation of the purpose and timing of MAT decisions for meniscectomy patients, suggesting a more proactive approach to recommending MAT, particularly for patients at high risk of postmeniscectomy syndrome and osteoarthritis progression.

Meniscal allograft transplantation: A matched-pair analysis reveals worse sport activity level but similar clinical improvement and survival in women compared to men

PURPOSE

The aim of this study was to assess how gender might affect the clinical outcome and survival of meniscal allograft transplantation (MAT).

METHODS

A total of 358 patients (23.2% women, 76.8% men) were treated with fresh-frozen nonirradiated allografts implantated arthroscopically using a single- or double-tunnel technique without bone plugs and peripheral suture to the capsule with 'all-inside' stitches.

RESULTS

Patients were evaluated at baseline and 2-year follow-up with the Lysholm score, visual analogue scale (VAS) pain, the Knee Osteoarthritis Outcome Score (KOOS) subscales and Tegner score. Women presented higher body mass index (p < 0.0005), poorer baseline VAS (p = 0.012), Lysholm score (p = 0.005), KOOS symptom (p = 0.034) and KOOS pain (p = 0.030), Tegner score (preinjury and basal, p < 0.0001 and p = 0.002, respectively), a lower number of previous (p = 0.039) and concurrent (p = 0.001) anterior cruciate ligament reconstructions and a higher number of concurrent procedures (p = 0.032) and distal femoral osteotomies (p = 0.024). Worse results were documented in women at 2 years, with lower Lysholm score (p = 0.024) and Tegner score (p = 0.007) and a lower clinical survival rate (p = 0.03) (67.5% vs. 82.2%) in the overall patient cohort. However, the matched-pair analysis only confirmed a lower Tegner score value at 2 years (p = 0.016), while underlying the interplay of sex, age and concomitant cartilage lesions in determining the clinical outcome. The analysis of this large series of patients affected by postmeniscectomy syndrome and treated with MAT revealed gender differences.

CONCLUSION

While both genders benefited from a significant improvement, the female population presents more often with older age, concomitant cartilage lesions and a lower activity level, all factors contributing towards a lower clinical success after MAT.

LEVEL OF EVIDENCE

Level III, comparative study.

Loss of chondroprotection of medial collagen meniscus implant (CMI) at 20-year follow-up

OBJECTIVE

The mid-term results of the collagen meniscus implant (CMI) procedure for the replacement of partial meniscus defects have already been described. However, there is a paucity of long-term comparative studies. This study aimed to compare the clinical outcomes, failures, and osteoarthritis progression of patients who underwent partial medial meniscectomy and medial CMI implantation.

METHODS

Thirty-six nonconsecutive patients with medial meniscus injuries that underwent medial CMI (MCMI) implantation or partial medial meniscectomy (PMM) between 1997 and 2000 were included in a prospective study with an intermediate 10-year follow-up examination and a final follow-up examination at 20-year follow-up. Outcome measures at the 20-year follow-up included the Lysholm score, visual analogue scale (VAS) for pain, International Knee Documentation Committee (IKDC) knee form , and Tegner activity level. Bilateral weight-bearing radiographs were also performed to evaluate hip-knee-angle (HKA) and the medial joint line height (JL). Data regarding complications and failures were also collected.

RESULTS

At the 20-year follow-up, 31 patients (83% follow-up rate) with a mean age of 60.7 ​± ​8.9 years were included in the final analysis (21.1 ​± ​1.2 years follow-up). Four reoperations and one failure per group were reported. When comparing the clinical results of the two groups, no difference was found considering the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner, and the IKDC. Moreover, 20 patients underwent radiographic examination (10 MCMI, 10 ​MM), and no statistically significant difference was reported concerning the JL, HKA, and the presence and incidence of osteoarthritis between the two groups.

CONCLUSION

The CMI implant for partial medial meniscectomy provided good long-term results and a low failure rate. However, differently from the 10 years follow-up, the clinical and the radiological outcomes were not superior compared to the medial meniscectomy group. The present study's result suggests that using a medial scaffold is not chondroprotective.

LEVEL OF EVIDENCE

III, Prospective case-control study.

Cellular Enhancement of Frozen Meniscus Allograft Combining Native Meniscus and Mesenchymal Stromal Cell Injections

OBJECTIVE

This proof-of-concept study investigated an improved cell-based injection therapy combining mesenchymal stem cells (MSCs) and meniscus cells (MCs) to support superior meniscus allograft repopulation and early revival compared to injecting MSCs alone.

DESIGN

In this controlled laboratory study, frozen meniscus allograft samples were injected vertically with a cell suspension containing different ratios of MSCs and MCs or control (lactated ringers) and cultured for 28 days. Samples were analyzed weekly for cell viability, migration, and metabolism using histological and biochemical assays. Tissue medium was analyzed for matrix metalloproteinase (MMP) expression using zymography.

RESULTS

Cellular repopulation of frozen allografts injected with different cell suspensions was validated by immunohistochemistry. Significant higher DNA content was evidenced in grafts treated with suspensions of MCs or MC:MSC (1:4 ratio). Cell metabolic activity was significantly different between all treated groups and control group after 1 week. Allografts injected with MCs showed significantly more cell proliferation than injections with MSCs. MMP2 activity was detected in medium of all grafts cellularized with MCs with or without MSCs. Scanning electron microscopy (SEM) analysis showed resolution of the needle puncture, but not in the control group. Cell labeling of MCs upon injection of mixed MC:MSC suspensions revealed a gradual increase in the cell ratio.

CONCLUSIONS

The findings of this study establish that injection of MCs with or without MSCs enhances the cellularity of meniscus allograft to support early graft revival and remodeling.

Survivorship of 157 Arthroscopic Meniscal Allograft Transplants Using Bone Fixation at a Mean of 7 Years and Prognostic Factors Analysis

BACKGROUND

Meniscal allograft transplantation (MAT) is an accepted and effective treatment option in the context of unsalvageable menisci, particularly in young and active patients. It has been shown to reduce pain and improve knee function in previously symptomatic patients. However, there is still limited knowledge about the long-term survival rates of allografts, the durability of clinical results, and the influence of patient-specific parameters, such as leg alignment, tibial slope, and preoperative International Cartilage Regeneration & Joint Preservation Society (ICRS) grade.

PURPOSE

To determine (1) the long-term clinical success rate after MAT with bony fixation in a large, single-center cohort of consecutive patients, and (2) if patient-specific and procedural variables influence the clinical, anatomic, and subjective outcomes and risk of failure.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data on 185 consecutive knees undergoing MAT in a single institution were prospectively collected and screened for inclusion in this study. The minimum follow-up time was 2 years. Radiographic variables (ICRS grade and Kellgren-Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (PROMs) (Lysholm score, Knee injury and Osteoarthritis Outcome Score [KOOS] including subscores, International Knee Documentation Committee [IKDC] score, and visual analog scale [VAS] score) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery due to graft failure or conversion to total knee arthroplasty. Anatomic failure was considered a tear covering >20% of the allograft, any peripheral tear, and unstable peripheral fixation leading to dislocation of the graft. Subjective failure was defined as Lysholm score ≤65. Preoperative tibial slope and leg alignment were assessed. Survival analyses were performed using the Kaplan-Meier estimate. Univariate and multivariate analyses were performed to determine risk factors for clinical and anatomic failure.

RESULTS

A total of 157 knees met inclusion criteria. After a mean follow-up time of 7 ± 3.5 years, 127 (80.9%) knees were free of clinical, anatomic, and subjective failure. Fourteen (8.9%) knees experienced clinical failure, 26 (16.6%) knees were identified as having experienced anatomic failure, and 13 (8.3%) patients experienced subjective failure with a reported Lysholm score of ≤65 at a mean follow-up of 7 years. Concurrent osteochondral allograft transplantation was identified as a predictor of both clinical (hazard ratio [HR], 4.55; 95% CI, 1.46-14.17; P = .009) and anatomic (HR, 3.05; 95% CI, 1.34-6.92; P = .008) failure. Cartilage damage of ICRS grade 3 or 4 of the index compartment conveyed an increased risk for clinical (HR, 3.41; 95% CI, 1.05-11.01; P = .04) and anatomic (HR, 3.04; 95% CI, 1.31-7.11; P = .01) failure. High-grade cartilage damage preoperatively (HR, 10.67; 95% CI, 1.037-109.768; P = .046), patient age >25 years (HR, 5.44; 95% CI, 0.120-246.070; P = .384), and a body mass index >30 (HR, 2.24; 95% CI, 0.748-6.705; P = .149) were associated with subjective failure. PROMs including KOOS and IKDC were significantly improved at final follow-up compared with preoperative scores across all measurements (P < .005).

CONCLUSION

MAT showed good to excellent clinical results at a mean follow-up of 7 years. Low ICRS lesion grade was associated with a higher clinical and anatomic survival rate. Patients with concurrent OCA transplantation are at a higher risk of clinical and anatomic failure, but still report significantly improved PROMs. These results suggest that MAT has a lasting beneficial effect both in isolation and in complex cases with ≥1 concurrent procedures.

A Transplant or a Patch? A Review of the Biologic Integration of Meniscus Allograft Transplantation

» After transplantation revascularization does occur although data are only available for animal models.» The time zero biomechanics, that is, the biomechanical properties at the time of transplant, of a meniscus allograft transplantation appear to appropriately mimic the original so long as the graft is sized correctly within 10% of the original and bone plug fixation is used.» Allograft type, that is, fresh vs. frozen, does not appear to affect the integration of the allograft.

Biomechanical Analysis Evaluating Meniscal Extrusion After Knotless Suture Anchor Fixation for Segmental Medial Meniscal Allograft Transplantation

Background

Segmental medial meniscal allograft transplantation (MAT) has been shown to restore knee biomechanics; however, stable fixation of the transplantation is critical to avoid extrusion and maximize healing.

Purpose

To evaluate the degree of meniscal extrusion and biomechanical function of segmental medial MAT performed with meniscocapsular sutures versus repair augmentation with knotless suture anchors.

Study Design

Controlled laboratory study.

Methods

Segmental midbody medial meniscectomy and subsequent segmental medial MAT were performed on 10 fresh-frozen cadaveric knees. The knees were then loaded in a dynamic tensile testing machine to 1000 N for 60 seconds at 0°, 30°, 60°, and 90° of flexion, and 4 conditions were tested: (1) intact, (2) segmental defect, (3) inside-out segmental repair, and (4) anchor plus inside-out segmental repair of the medial MAT. Meniscal extrusion was measured using high-fidelity ultrasound imaging. The mean contact area and the mean and peak contact pressures were assessed with submeniscal pressure-mapping sensors. Data from testing conditions were compared with 2-way repeated-measures analysis of variance, with pairwise comparison using the Bonferroni method.

Results

At 90° of flexion, the segmental defect state showed a higher degree of meniscal extrusion compared with all other states (P ≤ .012). There was no difference in the degree of meniscal extrusion between the intact state and the inside-out repair or anchor plus inside-out segmental repair states at all knee flexion angles (P > .05). There was no significant difference in the mean and peak contact pressures among the 4 states at all flexion angles except that at 0° of knee flexion there was significantly lower peak contact pressure at the medial compartment after anchor plus inside-out segmental repair compared with the segmental defect state (P = .048).

Conclusion

Meniscal extrusion was not significantly increased at any flexion angle after segmental resection. The addition of knotless anchors did not improve meniscal extrusion or contact pressures/area compared with capsular repair alone. The addition of knotless anchors did improve contact mechanics from the segmental defect state, but only at 0° of flexion.

Clinical Relevance

The addition of knotless suture anchors to segmental meniscal transplantation increased stabilization of the meniscus at full extension compared with repair with sutures alone. This increased stabilization may lead to better long-term outcomes.

Lateral Meniscal Allograft Transplantation Provides a Chondroprotective Effect on Articular Cartilage: Quantitative 3-T Magnetic Resonance Imaging T2 Mapping

PURPOSE

This study aimed to assess the cartilage status in patients who underwent isolated lateral meniscus allograft transplantation (MAT) using preoperative and postoperative quantitative 3-T magnetic resonance imaging T2 mapping at midterm follow-up period.

METHODS

Patients who underwent lateral MAT without cartilage treatment procedures between 2010 and 2019 were assessed by quantitative magnetic resonance imaging preoperatively and postoperatively. On the sagittal section image following the center of the lateral femoral condyle, the weight-bearing area of the articular cartilage was divided into 6 segments based on the meniscal coverage area from anterior to posterior direction. The mean T2 values of each of the 6 segments were measured for 3 regions of interest: overall, deep, and superficial layers. The change in T2 values was statistically analyzed by paired t-tests. The Lysholm score was used to evaluate clinical function.

RESULTS

A total of 105 patients were included in the study. The mean follow-up period was 3.2 years (range 2.0-5.4 years). Among the 6 segments, the mean T2 value showed significant improvement in the overall layer of F2 (the middle weight-bearing area of femoral condyle) and TP3 (the posterior weight-bearing area of tibia condyle) segments (P = .013 and .021, respectively) and the superficial layer of the F3 (the posterior weight-bearing area of femoral condyle) segments (P = .028). The mean T2 value of all the other segments did not show a statistically significant change. The mean Lysholm score significantly improved from 66.5 ± 15.8 to 89.3 ± 10.0 (P < .001). Overall, 73.3% and 96.2% of the patients met the minimal clinically important difference and patient acceptable symptomatic state, respectively.

CONCLUSIONS

The mean T2 value of the articular cartilage of the weight-bearing area was either maintained or showed statistically significant improvement depending on the location following isolated lateral MAT. Thus, the transplanted meniscus seems to have a chondroprotective effect on the weight-bearing cartilage.

LEVEL OF EVIDENCE

Level IV, retrospective therapeutic case series.

Nonextruded Grafts Result in Better Cartilage Quality After Lateral Meniscal Allograft Transplantation: Quantitative 3-T MRI T2 Mapping

BACKGROUND

Several studies have reported that graft extrusion after meniscal allograft transplantation (MAT) is associated with deterioration of surgical outcomes. However, no study has investigated the effect of graft extrusion on the articular cartilage using objective quantitative methods.

PURPOSE/HYPOTHESIS

This study aimed to investigate the influence of graft extrusion on the chondroprotective effect of lateral MAT on knee articular cartilage. We hypothesized that MAT without graft extrusion would result in better cartilage quality than MAT with graft extrusion.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Altogether, 105 patients who underwent isolated lateral MAT were divided into the extrusion and nonextrusion groups based on postoperative 3-month magnetic resonance imaging. Quantitative T2 mapping was performed on pre- and postoperative magnetic resonance imaging at midterm follow-up (mean ± SD, 3.2 ± 0.7 years). The weightbearing area of the femoral and tibial plateau articular cartilage was divided into 6 segments (F1, F2, F3, TP1, TP2, and TP3) from the anterior to posterior direction according to the meniscal coverage area. Each segment was further segmented into superficial and deep layers for zonal analysis. Longitudinal change in cartilage T2 value was compared between the groups. Lysholm scores were used to evaluate clinical function.

RESULTS

The mean T2 value of the nonextrusion group showed a significant improvement in 14 of 18 segments after lateral MAT, whereas the extrusion group demonstrated no statistically significant change. The biochemical properties of cartilage tissue as judged by quantitative T2 mapping indicated improvement in the nonextrusion group as compared with the extrusion group in the F2, TP2, and TP3 segments overall; the deep layers of the F1, F2, and TP2 segments; and the superficial layer of the TP3 segment (P < .05).

CONCLUSION

This study shows that the nonextruded graft results in better cartilage properties of the knee joint after lateral MAT as compared with the extruded graft at midterm follow-up.

Good clinical outcomes can be expected after meniscal allograft transplantation at 15 years of follow-up

PURPOSE

The aim of this study was to evaluate graft survivorship and report the functional and radiographic results of Meniscal allograft transplantation (MAT) throughout a minimum 15-year follow-up period.

METHODS

Fifty-one patients that had undergone an isolated MAT procedure during the period studied were included. The results were assessed with the Lysholm and Tegner scores as well as the Visual Analog Scale. Magnetic resonance imaging and a complete radiographic series were carried out to determine the degree of meniscal extrusion and joint space narrowing. A comparison was made between the radiological findings of the last follow-up, the 5-year mid-term follow-up and those from the preoperative period.

RESULTS

Thirty-eight patients were available for the final follow-up. The mean follow-up was 17.4 years. There were 23 (60.5%) medial menisci and 15 lateral menisci (39.4%). Meniscal extrusion increased from the 29.7% ± 14.9 obtained at the 5-year follow-up to the 72.5% ± 22.5 seen at the end of the follow-up (p = 0.0001). The joint space distance was almost unchanged from the initial evaluation (3.3 ± 1.5 mm) to the 5-year follow-up measurement (3.1 ± 1.7 mm, n.s.). However, it did decrease at the last follow-up (1.9 ± 1.5 mm, p < 0.05). The functional outcomes improved from the preoperative period to the mid-term follow-up and later worsened at the final follow-up. The mean preoperative Lysholm score at the initial follow-up was 61.5 ± 9.6, 86.9 ± 10.9 for the 5-year evaluation and stood at 77.4 ± 11.5 (p = 0.0001) at the final follow-up. Regarding the Tegner score, those pre-operative scores were compared to the ones at the last follow-up (median: 3; range 0-6 vs. 5.5; 3-6, respectively; p = 0.0001). The VAS went down from 6.6 ± 1.7 at the initial evaluation to 2.5 ± 1.9 at the final follow-up (p = 0.0001). The joint-space width remained unchanged from the initial evaluation (3.35 ± 1.5 mm) up to the 5-year follow-up measurement (3.1 ± 1.7 mm, n.s.). However, this joint-space distance had decreased by the last evaluation in the long-term follow-up (1.9 ± 1.4 mm, p < 0.05). Five patients (13.1%) presented with a MAT failure at 5 years, which was followed by extirpation of the meniscal graft. At the final follow-up, a total of 16 patients (42.1%) presented with a failure. At that time, there were 4 more MAT removals and seven patients that required a total knee replacement. The mean time to failure of the meniscal graft was 206.2 months ± 13.4 (18.0 years).

CONCLUSIONS

Meniscal allograft transplantation produces good functional results at a minimum 15-year follow-up. However, degenerative arthritis in the affected compartment progressed during that period.

LEVEL OF EVIDENCE

III.

The immediate meniscal allograft transplantation achieved better chondroprotection and less meniscus degeneration than the conventional delayed transplantation in the long-term

PURPOSE

The purpose of this study was to compare the long-term clinical and radiological outcomes between the immediate and delayed meniscus allograft transplantation (MAT).

METHODS

Nine menisci were transplanted immediately after total meniscectomy (immediate group, IM), and 10 menisci were delayed transplanted in patients with the median of 35 months (range 9-92 months) after total meniscectomy (delayed group, DE). Patient's subjective clinical outcomes including VAS, IKDC, Lysholm and Tegner scores as well as muscle strength measures were compared. Joint degeneration was evaluated by both radiographs to assess joint space width narrowing, Kellegren-Lawrence (KL) grade and MRI with T2 mapping sequences to quantitatively analyze both cartilage and meniscal allograft degeneration.

RESULTS

The median follow-up time was 10.8 years (range 10-14 years). The IKDC (IM vs DE, 89.8 vs 80.9, n.s.) and Lysholm scores (IM vs DE, 87.7 vs 78.0, n.s.) were close in two groups, while the IM group showed slightly lower VAS (IM vs DE, 0.2 vs 1.5, p = 0.031), higher Tegner score (IM vs DE, 7 vs 3.5 p = 0.021) and better quadriceps muscle strength. The IM group had less joint space narrowing (IM vs DE, 0.35 mm vs 0.71 mm, n.s.), less KL grade progression (IM vs DE, 0.6 vs 1.7, p = 0.041) on radiographs and less chondral lesions development on MRIs (Cartilage Degeneration Index, IM vs DE, 252 vs 2038, p = 0.025). All meniscal grafts exhibited degeneration by showing grade 3 signal on MRI, and 4 (4/9) in the IM group and 8 (8/10) cases in the DE group. The T2 value of cartilage and meniscal allograft in the IM group was close to that of the healthy control and was significantly lower than that of the DE group.

CONCLUSION

Compared to the conventional delayed MAT, the immediate MAT achieved better cartilage and meniscus protection in the long-term, while its superiority in patient-reported outcomes was limited.

LEVEL OF EVIDENCE

IV.

Correlation Between Anatomic Landmarks and Bony Trough Position in Lateral Meniscal Allograft Transplant

Background

Determining the rotational axis of the bony trough during lateral meniscal allograft transplant (MAT) is difficult. The use of anatomic landmarks may help a surgeon determine the rotational alignment of the graft during the procedure.

Purpose

To investigate the association between the knee's anatomic landmarks and the position of the bony trough to prevent extrusion after lateral MAT.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Enrolled were 44 patients who underwent lateral MAT between July 2000 and February 2011. The patients' mean age at the time of surgery was 30.8 years. Extrusion was measured on magnetic resonance imaging (MRI) scans at a mean of 3.6 months postoperatively, and patients were divided into an extrusion group (n = 15) and a no-extrusion group (n = 29). Three coronal MRI scans from each patient were selected, each from the region at the level of the tibial tuberosity (TT), the anterior bony trough, and the posterior bony trough. We measured the distance between the center of the anterior bony trough and the center of the TT (the TT distance) and the distance between the center of the posterior bony trough and the medial border of the lateral femoral condyle (LFC) (the LFC distance).

Results

The mean center of the anterior bony trough was in a more medial position relative to the center of the TT in the no-extrusion group (-2.9 ± 4.8 mm) compared with the extrusion group (1.3 ± 4.9 mm; P = .010). The mean center of the posterior bony trough was in a more medial position relative to the medial border of the LFC in the no-extrusion group (-1.7 ± 3.9 mm) compared with the extrusion group (1.0 ± 3.2 mm; P = .027). Both TT distance and LFC distance were significantly correlated with extrusion (P = .005 and .025, respectively). The cutoff value was -0.24 mm for the anterior bony trough and -0.58 mm for the posterior bony trough (negative values indicate that the trough was medial to the respective landmarks).

Conclusion

To prevent extrusion of the allograft, the center of the anterior bony trough needs to be aligned with the center of the TT, and the center of the posterior bony trough needs to be aligned with the medial border of the LFC.

Clinical significance and management of meniscal extrusion in different knee pathologies: a comprehensive review of the literature and treatment algorithm

The menisci are crescent-shaped, fibrocartilaginous structures that play a crucial role in the load transition and distribution of the contact forces along the tibiofemoral articulation. Meniscal extrusion (ME) is a radiological finding, especially in magnetic resonance imaging (MRI) scans, for which there has been growing interest in recent years. ME, in the coronary plane, is defined as the maximum distance of the most distal end of the meniscus from the border of the tibial plateau, where the tibial eminences are the most prominent, without taking into account the osteophytes. Although there is still controversy in the literature in respect of the optimal cutoff value, a threshold of 3 mm is considered significant. ME has no specific clinical finding or sign and it is encountered in many knee pathologies. It is associated with either rapidly progressive knee osteoarthritis or early onset of knee osteoarthritis and increased morbidity. In this review, we delineate the clinical significance of ME in various knee pathologies, as well as when, why and how it should be managed. To the best of our knowledge, this is the first study to elaborate on these topics.

Long sports career and satisfactory clinical outcomes after Meniscal Allograft Transplantation (MAT) in young professional athletes involved in strenuous sports

PURPOSE

To assess the return to sport rate of young professional athletes, to analyze their careers in terms of matches played and league participation over a minimum period of 6 years after Meniscal Allograft Transplantation (MAT), as well as to assess the long-term clinical subjective outcomes and satisfaction.

METHODS

Thirteen professional athletes (ten soccer and one basketball players, one fencer and one wrestler) with a mean age at surgery of 23.4 ± 4.0 underwent MAT (six medial, seven lateral). The time required to return to sport, post-operative performance level and the number of reoperations were evaluated. At an average follow-up of 9.0 ± 2.8 years, Lysholm, KOOS and Cincinnati scores were administered and collected.

RESULTS

Thirteen patients (100%) returned to sports practice after an average period of 11.8 ± 3.8 months. Nine athletes (69%) returned to sports at the same pre-injury level. Overall, 93%, 85%, 62% and 55% were active until the 3rd, the 5th, the 7th and the 9th season after MAT, respectively. Seven patients (54%) underwent a reoperation after MAT, where only two of them (15%) were related to graft problems (one meniscectomy and one graft suture). Of the ten athletes that completed subjective evaluation, the mean Lysholm score was 72 ± 15 (0% "Excellent", 10% "Good", 60% "Fair", 30% "Poor"). Of the athletes with lower scores, one suffered from patellar tendon rupture, one from post-operative infection and one from a previous femoral fracture. The mean Cincinnati knee score was 77 ± 18, while the average KOOS values were 60 ± 34 for sports.

CONCLUSION

Meniscal Allograft Transplantation (MAT) in young professional athletes involved in strenuous activities allowed all patients to return to pre-injury sport and in nearly 70% of cases at their pre-injury level. After five seasons following MAT, 85% of patients were still active or playing more than 20-30 matches per season. On the other hand, nearly 50% underwent at least one reoperation and only 70% of patients were rated as "Good", or "Fair" using the Lysholm score.

LEVEL OF EVIDENCE

IV.

Editorial Commentary: Knee Meniscal Allograft Transplantation Results in Significantly Improved Outcomes in the Majority Patients, but There Is Wide Variability in the Rate at Which Athletes Return to Sports

Meniscal allograft transplantation (MAT) is the reconstructive procedure of choice following a total or near-total meniscectomy for the symptomatic patient with a stable, well-aligned knee prior to the onset of degenerative arthritis. Historically, the goals were to eliminate symptoms with activities of daily living and improve longevity of the articular cartilage. However, athletically active individuals are rarely satisfied unless they return to their prior level of function, which is dependent on patient-specific, knee-specific, and sports-specific factors. Despite the fact that subjective patient-reported outcomes are significantly improved in the majority of MAT patients, there is wide variability in the rate at which athletic patients are able to return to sports, when they return, and their ultimate level of performance. We advise active individuals who undergo a MAT to pursue "low-impact" activities based on 10-year survivorship of 70% to 80%. Risk of a recurrent meniscal tear is the most common complication, and the ability of MAT to prevent osteoarthritis is unproven.

Human meniscus allograft augmentation by allogeneic mesenchymal stromal/stem cell injections

Meniscus allograft transplantations (MATs) represent established surgical procedures with proven outcomes. Yet, storage as frozen specimens and limited cellular repopulation may impair graft viability. This proof-of-concept study tests the feasibility of injecting allogeneic mesenchymal stromal/stem cells (MSCs) in meniscus allograft tissue. We investigated the injectable cell quantity, survival rate, migration, and proliferation ability of MSCs up to 28 days of incubation. In this controlled laboratory study, seven fresh-frozen human allografts were injected with human allogeneic MSCs. Cells were labeled and histological characteristics were microscopically imaged up to 28 days. Mock-injected menisci were included as negative controls in each experiment. Toluidine blue staining demonstrated that a 100-µl volume can be injected while retracting and rotating the inserted needle. Immediately after injection, labeled MSCs were distributed throughout the injection channel and eventually migrated into the surrounding tissues. Histological assessment revealed that MSCs cluster in disc-like shapes, parallel to the intrinsic lamination of the meniscus and around the vascular network. Quantification showed that more than 60% of cells were present in horizontally injected grafts and more than 30% were observed in vertically injected samples. On Day 14, cells adopted a spindle-shaped morphology and exhibited proliferative and migratory behaviors. On Day 28, live/dead ratio assessment revealed an approximately 80% cell survival. The study demonstrated the feasibility of injecting doses of MSCs (>0.1 million) in meniscus allograft tissue with active cell proliferation, migration, and robust cell survival.

Do Outcomes of Meniscal Allograft Transplantation Differ Based on Age and Sex? A Comparative Group Analysis

PURPOSE

To analyze the effect of patient age, sex, and associated preoperative factors on patient-reported outcome (PRO) measures and graft survival following primary meniscal allograft transplantation (MAT).

METHODS

A prospectively collected database was retrospectively reviewed to identify patients who underwent primary MAT with a minimum of 2 years of follow up between 1999 and 2017. Demographic, intraoperative, and postoperative outcome data were collected for each patient. Postoperative outcomes were stratified based on age and sex, and comparative statistical analysis was performed between sexes, both >40 and <40.

RESULTS

A total of 238 patients underwent primary MAT during the study period, of which 212 patients (mean age, 28.5 ± 9.0 years; range, 15.01-53.67 years) met the inclusion criteria with a mean follow-up of 5.1 ± 3.4 years (range 2.0-15.9 years). At final follow-up, patients ≥40 and <40 years of age demonstrated statistically significant improvements in nearly all PRO scores (P < .05 for both groups). There were no significant differences between either group for achievement of minimal clinically important difference for International Knee Documentation Committee (P = .48) or Knee Injury and Osteoarthritis Outcome Score symptoms (P = .76). Because of insufficient numbers, a statistically significant difference could not be demonstrated in reoperation rate (≥40: 1.49 ± 1.77 years, <40: 1.87 ± 1.98 years, P = .591), failure rate (≥40: 7/32 [21.9%], <40: 19/180 [10.6%], P = .072), or complication rate (≥40: 2/32 [6.3%], <40: 12/180 [6.7%], P = .930) based on age. Both sexes showed a significant improvement in PROs, whereas female patients were more likely to undergo revision surgery (P = .033), with no significant differences based on time to reoperation, failure, or complication rates.

CONCLUSIONS

PROs similarly improved following MAT in both patients aged ≥40 and those <40 at final follow-up with no significant differences in minimal clinically important difference achievement rate, complication rate, reoperation rate, time to reoperation, or failure rate between groups. Female patients may be more likely to undergo revision surgery after MAT.

LEVEL OF EVIDENCE

III; therapeutic retrospective comparison study.

Medial Meniscal Allograft Transplantation With Bone Plugs Using a 3-Tunnel Technique

Meniscal allograft transplantation is an area of active research, given that the importance of the meniscus in native knee joint longevity has been increasingly recognized. This article describes a modified meniscal allograft transplantation technique using 3 bone tunnels with allograft fixation through the use of bone plugs. The addition of a third tunnel increases the strength of fixation, avoiding meniscal extrusion and improving load distribution.

The Long-term Chondroprotective Effect of Meniscal Allograft Transplant: A 10- to 14-Year Follow-up Study

BACKGROUND

The long-term chondroprotective effect of meniscal allograft transplant (MAT) and its superiority over meniscectomy have rarely been reported.

HYPOTHESIS

MAT would reduce osteoarthritis (OA) progression when compared with the meniscus-deficient knee. Graft extrusion distance would strongly affect the chondroprotective effect of the MAT.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 17 knees receiving MAT were followed up as the MAT group. The MAT group was further divided into the nonextrusion subgroup (n = 9) and the extrusion subgroup (n = 8) according to 3-mm extrusion on the magnetic resonance imaging (MRI) coronal section. A further 26 consecutive patients receiving meniscectomy in the same period were followed up as the ME group. The healthy control group consisted of healthy contralateral legs chosen from the MAT and ME groups (n = 27). Joint space width (JSW) narrowing was measured on radiographs. Three-dimensional MRI with a T2 mapping sequence was used to quantitatively analyze cartilage degeneration and meniscal allograft extrusion in 5 directions (0°, 45°, 90°, 135°, and 180°). The cartilage degeneration index (CDI) was calculated according to the size and degree of the chondral lesions on MRI scans. The correlation between the CDI increase and the extrusion distance was analyzed.

RESULTS

The mean follow-up time was 11.3 years (range, 10-14 years). The MAT group had moderate superiority in chondral protection with less JSW narrowing (0.58 ± 0.66 mm) and CDI increase (1132 ± 1589) compared with the ME group (JSW narrowing: 1.26 ± 1.13 mm, P = .025; CDI increase: 2182 ± 1958, P = .079). The JSW narrowing (0.71 ± 0.80 mm; P = .186) and CDI increase (2004 ± 1965; P = .830) of the extrusion subgroup were close to those of the ME group, demonstrating that a 3-mm extrusion led to complete loss of the meniscal chondroprotective effect. The nonextrusion group had significantly less JSW narrowing (0.48 ± 0.48 mm; P = .042) and CDI increase (358 ± 249; P = .011) than the ME group. The JSW narrowing of the healthy control group was 0.22 ± 0.27 mm. The cartilage T2 values of the extrusion subgroup were similar to those of the ME group, with more OA features, whereas the T2 values of the nonextrusion subgroup were closer to those of the healthy control group. The extrusion distance in the 90° direction (P = .002) and the follow-up time (P = .019) significantly affected the CDI increase in the multivariate regression model. The average extrusion distance in the 45°, 90°, and 135° directions better predicted chondroprotection compared with the other individual directions.

CONCLUSION

MAT had moderate advantages in chondroprotection compared with meniscectomy in the long term. Graft extrusion distance strongly affected the chondroprotective effect of MAT. The chondroprotective effect of the nonextruded meniscal allograft was close to that of the native meniscus, whereas the allografts with an extrusion >3 mm completely lost their function after meniscectomy.

Autologous semitendinosus tendon graft could function as a meniscal transplant

PURPOSE

Meniscectomy results in poor knee function and increased risk for osteoarthritis. Meniscal allograft transplantation is not widely used due to costs and availability. The semitendinosus tendon (ST) has the potential to remodel and revascularize in an intraarticular environment, such as ACL reconstruction. The objective for this pilot study was to investigate whether the ST graft could function as a meniscal transplant.

METHODS

The ST was doubled and sutured with running sutures and pull-out sutures in each end. Bone tunnels were used for root anchorage and the graft was sutured with allinside, inside-out and outside-in technique. The pull-out sutures were fixed over a button. Partial weight bearing was allowed with limited range of motion in a brace for the first 6 weeks. Evaluation was assessed using clinical examination, radiology and patient reported outcome.

RESULTS

A total of seven patients have been included between January 2018 and June 2020. Six medial transplants and one lateral transplant were performed. Mean age was 29 years. Four patients had completed the 12-month follow-up. Improvements were noted for IKDC Global Score, KOOS pain subscale and Lysholm. MRI indicated that the transplant become more wedge-like with visible roots and minor protrusion.

CONCLUSIONS

Even though this is primarily a technical report the follow-up data indicate that the transplant survives and adapts in shape and capabilities to an original meniscus. There were no adverse events and the patients seem to improve in terms of pain and quality of life.

Clinical Replacement Strategies for Meniscus Tissue Deficiency

Meniscus tissue deficiency resulting from primary meniscectomy or meniscectomy after failed repair is a clinical challenge because the meniscus has little to no capacity for regeneration. Loss of meniscus tissue has been associated with early-onset knee osteoarthritis due to an increase in joint contact pressures in meniscectomized knees. Clinically available replacement strategies range from allograft transplantation to synthetic implants, including the collagen meniscus implant, ACTIfit, and NUSurface. Although short-term efficacy has been demonstrated with some of these treatments, factors such as long-term durability, chondroprotective efficacy, and return to sport activities in young patients remain unpredictable. Investigations of cell-based and tissue-engineered strategies to treat meniscus tissue deficiency are ongoing.

Biosynthetic scaffolds for partial meniscal loss: A systematic review from animal models to clinical practice

Acute or degenerative meniscus tears are the most common knee lesions. Meniscectomy provides symptomatic relief and functional recovery only in the short- to mid-term follow-up but significantly increases the risk of osteoarthritis. For this reason, preserving the meniscus is key, although it remains a challenge. Allograft transplants present many disadvantages, so during the last 20 years preclinical and clinical research focused on developing and investigating meniscal scaffolds. The aim of this systematic review was to collect and evaluate all the available evidence on biosynthetic scaffolds for meniscus regeneration both in vivo and in clinical studies. Three databases were searched: 46 in vivo preclinical studies and 30 clinical ones were found. Sixteen natural, 15 synthetic, and 15 hybrid scaffolds were studied in vivo. Among them, only 2 were translated into clinic: the Collagen Meniscus Implant, used in 11 studies, and the polyurethane-based scaffold Actifit®, applied in 19 studies. Although positive outcomes were described in the short- to mid-term, the number of concurrent procedures and the lack of randomized trials are the major limitations of the available clinical literature. Few in vivo studies also combined the use of cells or growth factors, but these augmentation strategies have not been applied in the clinical practice yet. Current solutions offer a significant but incomplete clinical improvement, and the regeneration potential is still unsatisfactory. Building upon the overall positive results of these "old" technologies to address partial meniscal loss, further innovation is urgently needed in this field to provide patients better joint sparing treatment options.

Arthroscopic Segmental Medial Meniscus Allograft Transplant Using Three Fixation Techniques

Partial meniscectomy or failed meniscus repair can lead to pain, dysfunction, and cartilage degradation due to increased contact forces. Meniscus transplantation can lead to favorable outcomes and cartilage preservation with careful patient selection. Limited data exist on segmental meniscus allograft transplantation, with promising results using synthetic grafts and early animal and biomechanical studies on segmental allograft transplantation, showing similar results to full meniscus allograft transplantation. This article presents a technique for arthroscopic segmental medial meniscus allograft transplant and a brief review of the literature.

Prognostic Factors to Determine Survivorship of Meniscal Allograft Transplant: A Systematic Review

Background:

There is much room for improvement and optimization of meniscal allograft survivorship.

Purpose:

To understand prognostic factors for survivorship using evidence-based selection criteria in order to identify patients who would best benefit from meniscal allograft transplant (MAT).

Study Design:

Systematic review; Level of evidence, 4.

Methods:

We conducted this systematic review to analyze prognostic factors for survivorship of MAT. The Cochrane Central Register, PubMed publisher, Embase.com, and Web of Science databases were searched through August 8, 2019. Included studies entailed patients of any age who received MAT with a reported association between prognostic factors and survivorship of the allograft. Two reviewers independently screened all titles and abstracts for eligibility, extracted the data, assessed the risk of bias using the Newcastle-Ottawa Scale, and performed a best-evidence synthesis.

Results:

The review included 18 studies with a total of 1920 patients. The mean follow-up time was 6.0 years (range, 2.1-11.2 years). A total of 20 prognostic factors were identified and shown to be associated with survivorship of MAT. Strong evidence was found that severe cartilage damage was associated with poor survivorship. Strong evidence was also found showing that sex, knee compartment, surgical side, concomitant anterior cruciate ligament (ACL) reconstruction, and concomitant osteotomy for malalignment had no effect on survivorship. Moderate evidence was found that body mass index (<36), tobacco use, and arthroscopic versus open procedure had no influence on survivorship. Conflicting evidence was found that older age and kissing cartilage lesions (lesions on both the femur and tibia vs on a single side) decreased survivorship.

Conclusion:

Severe cartilage damage decreases the survivorship of MAT. Concomitant ACL reconstruction and osteotomy showed no relationship to survivorship. Many determinants showed conflicting and limited evidence. Older age may be of interest and should be further studied.

[Relevance of meniscus loss for the progression of osteoarthritis and treatment options for early arthritis]

Meniscal tears are still one of the most frequent lesions in the knee joint. The relevance of meniscus loss for the development of osteoarthritis is undisputed. Meniscus repair, replacement and transplantation play an important role in the treatment of early arthritis, especially when they are a part of a master plan including alignment correction, stabilization and cartilage surgery, if needed. Scientific data show evidence concerning the protection of osteoarthritis, even though a lack of studies including comparison groups has to be admitted.

Progression of Allograft Extrusion in Both the Coronal and Sagittal Planes at Midterm Follow-up After Medial Meniscal Allograft Transplant

Background

Although many studies have examined allograft extrusion after medial meniscal allograft transplant (MMAT), it is unclear whether allograft extrusion progresses at midterm follow-up.

Hypothesis

After MMAT, allograft extrusion would not progress during the midterm follow-up period.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 30 patients who underwent MMAT between December 1996 and March 2016 were enrolled. Allograft extrusion was measured on magnetic resonance imaging scans obtained at 6 weeks, 1 year, and 3 to 7 years postoperatively. In the coronal plane, the absolute allograft extrusion and relative percentage of extrusion were measured. In the sagittal plane, the absolute and relative anterior cartilage meniscal distance and posterior cartilage meniscal distance were measured. The joint-space width (JSW) on radiographic Rosenberg view was measured at 3 time points. The axial alignment was measured preoperatively and at the midterm follow-up.

Results

In the coronal plane, there were no significant differences in absolute and relative coronal extrusions between 6 weeks and 1 year postoperatively; however, the values were significantly increased at midterm follow-up compared with both of the earlier follow-up periods. Similarly, in the sagittal plane, the mean absolute and relative anterior and posterior cartilage meniscal distances were not significantly different between 6 weeks and 1 year postoperatively but showed significant increases at midterm follow-up compared with both of the earlier follow-up periods. The mean preoperative axial alignment showed a positive correlation with the delta value of relative percentage of extrusion in the coronal plane (r = 0.378; P = .036). The mean JSW was 4.42 ± 0.88 mm preoperatively, 4.30 ± 0.83 mm at 1-year follow-up, and 3.96 ± 1.06 mm at the midterm follow-up. No significant difference was found between the preoperative and postoperative 1-year values, but the mean JSW was significantly decreased at midterm follow-up compared with both of the other time points (P = .001 for both).

Conclusion

Allograft extrusion did not progress until 1 year after MMAT; however, by midterm follow-up, extrusion had progressed in both the coronal and the sagittal planes. Preoperative axial alignment showed a positive correlation with allograft extrusion in the coronal plane.

Predictors of Meniscal Allograft Transplantation Outcome: A Systematic Review

This systematic review investigates factors associated with outcomes after meniscal allograft transplantation (MAT). The PubMed, Scopus, and Cochrane Central Register databases were used to search relevant articles in April 2018. Studies that evaluated at least one association between a factor and outcomes were extracted. Of 3,381 titles, 52 studies were finally analyzed. Data about predictors, patient-reported outcome scores (PROMs), and failure rates were extracted for quantitative and qualitative analysis. A total of 3,382 patients and 3,460 transplants were identified. Thirty different predictors were reported in the current MAT literature, 18 of which by at least two studies. Subgroup analysis showed that lateral MAT had higher postoperative values than medial MAT in Lysholm's (p = 0.0102) and International Knee Documentation Committee (IKDC; p = 0.0056) scores. Soft tissue fixation showed higher postoperative IKDC scores than bone fixation (p = 0.0008). Fresh frozen allografts had higher Lysholm's scores (p < 0.0001) and showed significantly lower failure rates (p < 0.0001) than cryopreserved allografts. Age (p < 0.015, β = 0.80), sex (p < 0.034, β  =  - 8.52), and body mass index (BMI; p < 0.014, β = -4.87) demonstrated an association with PROMs in the regression model. Qualitative analysis found moderate evidence that a higher number of previous procedures in the same knee are an independent predictor of transplant failure. Conflicting evidence was found with regard to chondral damage, time from meniscectomy, smoke, sport level, worker's compensation status, and preoperative Lysholm's score as predictors of outcomes. Our review suggests that the ideal candidate to undergo MAT may be a young male of normal weight with no previous knee surgeries, treated with a lateral isolated procedure. However, MAT is associated with good outcomes in the majority of patients with many of the PROMs requiring further study to determine their direct effects on long-term outcomes. This study is a systematic review and reflects level of evidence IV.

Treatment of Meniscal Deficiency with Meniscal Allograft Transplantation and Femoral Osteotomy in a Patient with History of Lateral Discoid Meniscus: 15-Year Follow-up Case Report

CASE

A 15-year-old woman with multiple arthroscopic procedures for left lateral discoid meniscus since the age of 9 presented with pain, swelling, and mechanical symptoms. A meniscal allograft transplantation (MAT) and lateral opening-wedge femoral osteotomy was performed. At the 6-year follow-up, the patient presented a visual analog scale (VAS) score of 0, subjective International Knee Documentation Committee (IKDC) of 88, and Lysholm of 95. At 15-year follow-up, the VAS score was 0, subjective IKDC 85.1, and Lysholm 86.

CONCLUSIONS

MAT associated with femoral osteotomy was an effective procedure in this patient with pain and functional limitation after total meniscectomy in the setting of discoid meniscus and valgus malalignment. Good clinical and magnetic resonance imaging-related outcomes were achieved at the intermediate and long-term follow-up.

Satisfactory clinical results and low failure rate of medial collagen meniscus implant (CMI) at a minimum 20 years of follow-up

PURPOSE

The aim of the study was to evaluate the long-term clinical results, reoperations, surgical failure and complications at a minimum of 20 year of follow-up of the first 8 medial CMI scaffolds implanted by a single surgeon during a pilot European Prospective study.

METHODS

Seven (88%) out of 8 patients were contacted. The Cincinnati Score, VAS, and Lysholm score were collected. Moreover, magnetic resonance imaging (MRI) was performed on 4 patients at the last follow-up. Complications, reoperations and failures were also investigated.

RESULTS

The average follow-up was 21.5 ± 0.5 years. One patient underwent TKA after 13 years from CMI implantation; a second patient underwent valgus high tibial osteotomy 8 years after the index surgery and another patient underwent anterior cruciate ligament hardware removal at 21 years of follow-up. At the final follow-up, 3 patients were rated as "Excellent", 1 as "Good" and 2 as "Fair" according to the Lysholm score. The Cincinnati score and the VAS were substantially stable over time. The MRI showed a mild osteoarthritis progression in 3 out of 4 patients according to the Yulish score, and the CMI signal was similar to the mid-term follow-up revealing 3 cases of myxoid degeneration and 1 case of normal signal with reduced scaffold size.

CONCLUSION

The medial CMI is a safe procedure: satisfactory clinical results and a low failure rate could be expected even at a long-term follow-up. For this purpose, the correct indication as well as correcting axial malalignment and addressing knee instability at the time of the index surgery is mandatory. On the other hand, a mild osteoarthritis progression could be expected even after meniscus replacement.

LEVEL OF EVIDENCE

IV.

Large chondral defect not covered by meniscal allograft is associated with inferior graft survivorship after lateral meniscal allograft transplantation

PURPOSE

This study aimed to evaluate graft survivorship according to the size and location of chondral defects and its effect on clinical outcomes after meniscal allograft transplantation (MAT). It was hypothesized that large chondral defects would be associated with inferior outcomes.

METHODS

Patients who underwent lateral MAT with fresh-frozen allografts between 2007 and 2016 were retrospectively reviewed. The inclusion criteria were patients with femoral or tibial chondral defects (International Cartilage Repair Society grade 4) who were followed up more than 2 years with 3.0-T magnetic resonance imaging (MRI) scans. Maximal lesion diameter and location were assessed on MRI. The patients were divided into two groups, with chondral defects of < 3 and ≥ 3 cm² on the tibial side. Graft survivorship was compared between the two groups. Graft failure was defined as revisional MAT, meniscal tear or meniscectomy greater than one-third of the allograft on MRI. Clinical outcomes were evaluated using the modified Lysholm score.

RESULTS

Twenty-eight knees in 26 patients (mean age 37.4 ± 10.3 years) with a mean follow-up of 3.6 ± 1.0 (range 2.0-5.4) years were identified. Nineteen knees in 17 patients had both femoral and tibial chondral defects, 7 knees in 7 patients had only femoral chondral defects, and 2 knees in 2 patients had only tibial chondral defects. The mean preoperative femoral and tibial chondral defect sizes were 1.7 ± 1.2 and 3.0 ± 1.4 cm², respectively. Among the seven graft failures, no graft failure occurred in the cases with tibial chondral defects of < 3 cm². Tibial chondral defects of ≥ 3 cm² were significantly associated with graft failure (P = 0.004; odds ratio 28.3; 95% confidence interval 2.5-4006.7). Defects of < 3 cm² were located primarily in the posterior aspect of the lateral tibial plateau, and most lesions were covered by allograft (7/9, 77.8%). The modified Lysholm scores significantly improved irrespective of chondral defects size (P < 0.001).

CONCLUSIONS

Larger chondral defects, more than 3 cm² on the tibial side, were associated with inferior graft survivorship but did not influence the clinical outcomes after MAT at the 3.6-year follow-up. Chondral defect location was associated with defect size.

LEVEL OF EVIDENCE

IV.

The menisci and articular cartilage: a life-long fascination

The menisci and articular cartilage of the knee have a close embryological, anatomical and functional relationship, which explains why often a pathology of one also affects the other.

Traumatic meniscus tears should be repaired, when possible, to protect the articular cartilage.

Traumatic articular cartilage lesions can be treated with success using biological treatment options such as microfracture or microdrilling, autologous chondrocyte transplantation (ACT), or osteochondral transplantation (OCT) depending on the depth and area of the lesion.

Degenerative cartilage and meniscus lesions often occur together, and osteoarthritis is already present or impending. Most degenerative meniscus lesions should be treated first conservatively and, after failed conservative treatment, should undergo arthroscopic partial meniscus resection. Degenerative cartilage lesions should also be treated conservatively initially and then surgically; thereby treating the cartilage defect itself and also maintaining the axis of the leg if necessary.

Tears of the meniscus roots are devastating injuries to the knee and should be repaired e.g. by transtibial re-fixation.

The clinical role of ‘ramp’ lesions of the meniscus is still under investigation.

Cite this article: EFORT Open Rev 2020;5:652-662. DOI: 10.1302/2058-5241.5.200016

An Up-to-Date Review of the Meniscus Literature: A Systematic Summary of Systematic Reviews and Meta-analyses

Background:

A large number of systematic reviews and meta-analyses regarding the meniscus have been published.

Purpose:

To provide a qualitative summary of the published systematic reviews and meta-analyses regarding the meniscus.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search of all meta-analyses and systematic reviews regarding the meniscus and published between July 2009 and July 2019 was performed with PubMed, CINAHL, EMBASE, and the Cochrane database. Published abstracts, narrative reviews, articles not written in English, commentaries, study protocols, and topics that were not focused on the meniscus were excluded. The most pertinent results were extracted and summarized from each study.

Results:

A total of 332 articles were found, of which 142 were included. Included articles were summarized and divided into 16 topics: epidemiology, diagnosis, histology, biomechanics, comorbid pathology, animal models, arthroscopic partial meniscectomy (APM), meniscal repair, meniscal root repairs, meniscal allograft transplantation (MAT), meniscal implants and scaffolds, mesenchymal stem cells and growth factors, postoperative rehabilitation, postoperative imaging assessment, patient-reported outcome measures, and cost-effectiveness. The majority of articles focused on APM (20%), MAT (18%), and meniscal repair (17%).

Conclusion:

This summary of systematic reviews and meta-analyses delivers surgeons a single source of the current evidence regarding the meniscus.

Risk of Subsequent Knee Arthroplasty After Sports Medicine Procedures

INTRODUCTION

Approximately 10% of men and 13% of women older than the age of 60 are affected by symptomatic osteoarthritis of the knee. Anatomic repair or reconstruction after knee injury has been a central tenet of surgical treatment to reduce the risk of osteoarthritis. The purpose of this study was to examine common sports medicine procedures of the knee and determine the proportion of patients who subsequently undergo total knee arthroplasty (TKA).

METHODS

The MarketScan database was queried from the period of January 2007 through December 2016. Patients were identified, who underwent a procedure of the knee, as defined by Current Procedural Terminology codes relating to nonarthroplasty procedures of the knee. Patients in whom laterality could not be confirmed or underwent another ipsilateral knee procedure before TKA were excluded from this study. The primary outcome of this study was the overall rate of TKA after index knee surgery. Time from index procedure to TKA was a secondary outcome. A multivariate regression analysis was used to control for covariates such as age, sex, and comorbidity status.

RESULTS

A total of 843,749 patients underwent one of the 13 common sports medicine procedures of the knee. The procedure with the highest unadjusted rate of subsequent TKA was arthroscopic osteochondral allograft (5.81%), whereas anterior cruciate ligament (ACL) reconstruction with meniscus repair demonstrated the lowest rate of subsequent TKA (0.01%). When adjusting for confounding factors, the regression analysis identified meniscal transplantation (odds ratio [OR] = 3.06, P < 0.0001) as having the highest risk of subsequent TKA, followed by osteochondral autograft (OR = 1.74, P = 0.0424) and arthroscopic osteochondral allograft (OR = 1.49, P < 0.0001). ACL reconstruction with meniscus repair (OR = 0.02, P < 0.0001), ACL reconstruction alone (OR = 0.17, P < 0.0001), ACL with meniscectomy (OR = 0.20, P < 0.0001), and meniscal repair (OR = 0.65, P < 0.0001) had the lowest rate of subsequent TKA. ACL reconstruction with meniscus repair had the longest period from index procedure to TKA at 2827 days.

CONCLUSION

ACL reconstruction and meniscus preservation demonstrated an extremely low rate of conversion to TKA when compared with patients who needed salvage interventions such as meniscus and cartilage transplantation. None of the salvage interventions delayed the need for a TKA. Meniscal transplantation had the highest risk of all procedures of going on to a TKA.

Long-term Outcomes and Survivorship of Fresh-Frozen Meniscal Allograft Transplant With Soft Tissue Fixation: Minimum 10-Year Follow-up Study

BACKGROUND

Meniscal allograft transplant (MAT) is considered an effective procedure for reducing pain and improving knee function. Nevertheless, the current knowledge regarding the results of MAT is limited to short- to mid-term follow-up studies, especially for arthroscopic techniques.

PURPOSE

To evaluate the long-term clinical outcomes, reoperations, and failures with a minimum follow-up of 10 years after fresh-frozen MAT performed arthroscopically with soft tissue fixation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 46 patients (age, 36.6 ± 10.6 years; 36 male, 10 female) who underwent medial MAT (n = 27) or lateral MAT (n = 19) with a minimum 10-year follow-up were evaluated with the Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale for pain, and Tegner score. Surgical failure was defined as the need for partial or total graft removal (meniscectomy or knee replacement), and clinical failure was defined as the need for partial or total graft removal in addition to a poor Lysholm score (<65 points) at final follow-up. Survival analysis was performed with Kaplan-Meier curve, and clinical scores were analyzed based on the Patient Acceptable Symptom State (PASS) for MAT.

RESULTS

10-year survival and clinical data were available for 38 patients. Because 6 meniscectomies were required, the rate of survival free from surgical failure was 91% at 5 years and 86% at 10 years. Lower survival was reported in lateral MAT (73%) compared with medial MAT (96%). Because a further 4 patients had poor Lysholm scores, the rate of survival free from surgical and clinical failure was 87% at 5 years and 70% at 10 years. The average Lysholm score at final follow-up was 82 ± 20, and 60% to 82% of patients achieved PASS of the various KOOS subscales. The Tegner score and the KOOS Sport score significantly decreased from mid-term to long-term evaluation (P < .001 and P < .05, respectively). Other KOOS subscales and the Lysholm score remained stable at long-term evaluation. No significant differences were found between isolated MAT or combined MAT regarding subjective scores, surgical failures, or clinical failures.

CONCLUSION

Up to 10 years after surgery, 86% of fresh-frozen MATs with soft tissue fixation were still in situ, and satisfactory clinical results were present for about 70% of patients. Decline of clinical outcomes from midterm to long term was noted only in sports-related scores. A higher number of overall reoperations was noted in female patients, whereas a higher risk of failure was present in the patients with lateral MAT.

Editorial Commentary: Return to Sport Should Not Be Your Goal Following High Tibial Osteotomy With Concomitant Medial Meniscal Allograft Transplantation

Meniscal allograft transplantation has been done for 3 decades as a salvage procedure for patients with painful compartments following total or near-total meniscectomy. In malaligned joints, periarticular osteotomies often are performed in conjunction with the transplantation. The goal has been to reduce pain and improve function. Early series showed that retear of transplanted menisci was common. Because many recipients of meniscal transplantations are young, the goal has been to reduce pain and restore function, and high-demand work or sporting activities have been discouraged.

A Magnetic Resonance Imaging Analysis of Shrinkage of Transplanted Fresh-Frozen Lateral Meniscal Allografts During a Minimum Follow-up of 8 Years

PURPOSE

To evaluate the incidence and degree of shrinkage of transplanted fresh-frozen meniscal allografts in a long-term period of >8 years and to investigate whether the shrinkage of allograft progresses and is associated with inferior clinical and radiologic outcomes after meniscal allograft transplantation (MAT) in the long term.

METHODS

Twenty-two knees were reviewed in 20 patients (mean age, 31.41 ± 9.11 years) who underwent isolated lateral MAT. All patients were followed with magnetic resonance imaging (MRI) for at least 8 years (mean, 11.78 ± 3.10 years). The allograft widths of the anterior horn, mid-body, and posterior horn at 1 and >8 years postoperatively were measured by using MRI. To estimate the degree of shrinkage, the relative changes in widths during intervals were calculated. Patients were categorized into 4 groups according to shrinkage degree: minimal (<10%), mild (10%-25%), moderate (25%-50%), and severe (>50%). The joint space width was measured on the weightbearing radiographs to evaluate the radiologic outcome. The Lysholm score was used to evaluate the clinical outcome.

RESULTS

The relative change in the width of the anterior horn, mid-body, and posterior horn, compared with that 1 year postoperatively, was 82.7% (95% confidence interval 77.4%-87.5%), 75.9% (70.7%-81.0%), and 85.0% (81.4%-88.5%), respectively. The shrinkage degree was greater at the mid-body than at the anterior and posterior horns. About 70% of allografts showed ≥10% shrinkage of the posterior horn. Meniscal shrinkage did not show significant correlation with clinical and radiologic outcome.

CONCLUSIONS

At long-term follow-up (>8 years), shrinkage of transplanted fresh-frozen meniscal allografts progressed at 1 year postoperative. On average, the shrinkage was mild and more prominent in the mid-body than in the anterior or posterior horn. In this study, it could not be concluded that the shrinkage of allografts was significantly associated with inferior clinical and radiologic outcomes in the long term.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Arthroscopic Medial Meniscal Transplant Using Multiple Fixation Techniques

The critical role of the meniscus in the biomechanics of the knee and articular cartilage preservation has led to an increased awareness of the importance of the meniscus. Meniscal allograft transplantation is a challenging surgical intervention that is saved as a last resort for patients who meet stringent criteria for salvage from meniscal deficiency. Proper arthroscopic implantation of a meniscal allograft takes precision and implementation of multiple fixation techniques to obtain a successful outcome.

Clinical outcomes and survival rate of autologous chondrocyte implantation with and without concomitant meniscus allograft transplantation: 10- to 15-year follow-up study

PURPOSE

The purpose of this study was to compare the clinical outcomes and survival rate of autologous chondrocyte implantation (ACI) with or without concomitant meniscus allograft transplantation (MAT).

METHODS

Patients who underwent ACI of the medial or lateral femoral condyle with or without concomitant MAT were retrospectively reviewed. There were 14 patients (mean age, 31.2 ± 9.9 years) who underwent isolated ACI and 19 patients who underwent ACI with concomitant MAT (mean age, 34.8 ± 8.4 years). The International Knee Documentation Committee (IKDC) subjective score, Lysholm score, Tegner activity score, and 10- to 15-year survival rate were compared between groups.

RESULTS

All clinical scores showed significant improvement postoperatively in both groups. At final follow-up, the IKDC subjective score was superior in isolated ACI (75.8 ± 18.4) compared to ACI with MAT (61.0 ± 16.6, p = 0.024). The Lysholm score was also higher in isolated ACI (77.5 ± 19.1) than ACI with MAT (62.5 ± 18.1, p = 0.029). The Tegner activity score did not differ between treatments (isolated ACI, 5.3 ± 1.1; ACI with MAT, 4.5 ± 1.3; p = 0.072). The 15-year survival rate for isolated ACI was higher than that of ACI with concomitant MAT (69.6% vs 50.2%), but this difference was not statistically significant (p = 0.19).

CONCLUSIONS

ACI with concomitant MAT did not restore clinical outcomes as much as isolated ACI. There was a trend for the long-term survival rate to be greater in isolated ACI than ACI with MAT. These results should be considered in planning for the treatment of focal chondral defect with meniscus deficiency.

LEVEL OF STUDY

Retrospective comparative trial; level of evidence, 3.

Meniscal Allograft Transplantation Is an Effective Treatment in Patients Older Than 50 Years but Yields Inferior Results Compared With Younger Patients: A Case-Control Study

PURPOSE

To evaluate the influence of age on midterm clinical outcomes and failures of meniscal allograft transplantation (MAT), aiming at investigating the efficacy of MAT in patients older than 50 years.

METHODS

In this case-control study, data on patients older than 50 years (older MAT [O-MAT] group) with at least 5 years of follow-up and a matched-pair group of patients younger than 30 years of age (younger MAT [Y-MAT] group) were extracted from a database of MAT procedures, performed with arthroscopic implantation of fresh-frozen meniscal allograft without bone plugs.

RESULTS

A matched-pair comparative analysis of midterm results and survival between 26 O-MAT patients and 26 Y-MAT patients was performed at a mean follow-up of 7.3 ± 2.2 years. All the clinical scores significantly improved from the baseline values in both the O-MAT and Y-MAT groups although with significantly lower scores in the O-MAT group. Two-thirds of O-MAT patients were able to return to a recreational level of sports activity. Only 2 patients in the O-MAT group underwent knee replacement, but the overall failure rate, also considering a clinical criterion, was 31% in the O-MAT group and 15% in the Y-MAT group (P = .3244). The mean survival time free from replacement or graft removal was 11.6 years in the O-MAT group and 12.3 years in the Y-MAT group (P = .691).

CONCLUSIONS

MAT is able to provide symptom relief and functional improvement at midterm follow-up in patients older than 50 years although with inferior results and a higher failure rate compared with those younger than 30 years. MAT can be considered a viable option to treat patients older than 50 years.

LEVEL OF EVIDENCE

Level III, case-control study.