Save the meniscus again!

Editorial Commentary: Rate of Meniscal Repair Versus Meniscectomy Has Improved and Should Continue to Improve

As a result of research supporting meniscus preservation, evidence shows that internationally, there has been a rise in rates of meniscus repair, especially in younger population, and a decline in rates of partial meniscectomy. The decline in partial meniscectomy has been rather rapid and has outpaced the rise in meniscal repair, likely due to increasing evidence against routine partial meniscectomy in degenerative tears with coexistent arthritis. However, despite the rise in meniscus repair, close to 95% of meniscus surgeries are still partial meniscectomies. The partial meniscectomy to meniscus repair ratio seems to be rather high. Optimistically, this will improve because successful repair outcomes have been demonstrated in situations previously considered "high-risk," including complex patterns, central tears, radial tears, and root and ramp tears. This may be due to multiple factors, many of which may be beyond the control of surgeons, including the fact that as many as 25% of repairs fail to heal. Yet, with improved techniques and instrumentation, the success rate of repair is improving. The cost of repair may be a limiting factor, especially in low-income countries with poor health insurance penetration and unfavorable reimbursement of repair cost. Every effort must be made to repair a tear, which has potential to heal.

Decreasing Incidence of Partial Meniscectomy and Increasing Incidence of Meniscus Preservation Surgery From 2010 to 2020 in the United States

PURPOSE

To characterize the incidence of meniscus surgery from 2010 to 2020 in the United States, using the metrics of age, sex, type of meniscus surgery, and Charlson Comorbidity Index (CCI).

METHODS

A retrospective analysis was performed using the PearlDiver national insurance claims database from 2010 to 2020. Meniscus surgeries were identified using Current Procedural Terminology codes. Patients were stratified by procedure type, age, biological sex, and CCI scores. Compound annual growth rate analysis and analysis of variance were performed to analyze the trends and demographic variables between cohorts.

RESULTS

Of 2,053,884 meniscus surgeries, 94.7% were meniscectomies, 0.3% were open repairs, 4.9% were arthroscopic repairs, and 0.1% were meniscal transplantations. Compound annual growth rate analysis displayed a 4.0% decrease per year in total meniscus surgery. For individual procedure types, the largest decrease was in meniscectomy, and the largest increase was in open repair. Patients undergoing meniscal transplantation were youngest, with the lowest CCI. Meniscectomy patients were oldest, and open repair patients had the highest average CCI. Most procedures were performed on female patients (52.4%) and patients in the 50- to 59-year age group (30.4%).

CONCLUSIONS

There was a sustained decrease in the incidence of total meniscus surgeries from 2010 to 2020. Meniscectomy was the procedure with the highest incidence, but it showed the most significant decline in usage over the study period. Conversely, meniscal repair and transplantation procedures increased during the study period.

LEVEL OF EVIDENCE

Level IV, epidemiologic study.

Meniscal Bucket-Handle Tears and Return to Sports in Young Adults: A Systematic Review and Meta-Analysis

Bucket-handle tears represent a subtype of meniscal injuries that involve a full-thickness longitudinal tear. These tears are challenging and demanding. The present systematic review and meta-analysis aimed to evaluate return-to-sport outcomes in young adults with isolated bucket-handle meniscal tears treated surgically through meniscal repair. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with two independent reviewers selecting studies from PubMed, Web of Science, and Scopus databases. Studies were included if they involved patients over 16 years old, with isolated bucket-handle tears, a minimum of one-year follow-up, and reported postoperative Tegner scores. Five studies comprising 168 individual knees met these criteria and were analyzed. Quality assessment employed the Newcastle-Ottawa Scale. Data analysis was conducted in R (R Foundation for Statistical Computing, Vienna, Austria) for pooled outcome calculations. The primary outcome was the postoperative Tegner score, representing a return to sports; secondary outcomes included changes in Tegner and Lysholm scores and failure rates. Two cohort studies and three case series were included, with quality ratings ranging from fair to poor. The mean patient age was 27.8 years, and the mean follow-up was 82.4 months. The pooled postoperative Tegner score was 5.94 (95% CI: 5.41-6.46), indicating a high return to recreational sports. The mean change in Tegner score was 2.48 (p = 0.0604), which was not statistically significant, while Lysholm score improvement was significant at 31.16 points (p = 0.0093). The pooled failure rate across studies was 14% (95% CI: 0-42%). Patients with isolated bucket-handle meniscal tears undergoing surgical repair demonstrate a high rate of return to recreational sports, with significant improvements in Lysholm scores. However, failure rates and study quality variability suggest further high-quality research to make safer conclusions.

Long-term clinical and radiological outcomes after arthroscopic partial meniscectomy on stable knees are better for traumatic tears when compared to degenerative lesions: A systematic review

PURPOSE

An arthroscopic partial meniscectomy (APM) for degenerative meniscus lesions and traumatic meniscus tears are two distinct entities and their long-term outcomes are rarely reported. The aim of this review was to compare the long-term (clinical and radiological) results of APM performed on stable knees for traumatic tears (TT) or degenerative lesions (DL).

METHODS

Pubmed, Scopus and Embase databases were searched to identify relevant studies published between 2010 and 2023 using the keywords 'meniscectomy' OR 'meniscectomies' OR 'meniscal resection'. English-language, Levels I-IV evidence studies reporting either radiographic or clinical outcome measures with a minimum of 6 years' follow-up after APM were included. Studies including discoid meniscus, open meniscectomy, unstable knee and combination with other procedures were excluded. To rate the quality of evidence, the methodological index for non-randomized studies was used.

RESULTS

Thirty-two studies were included, with follow-up periods ranging from 6 to 22 years. Eleven studies dealt with TT with a mean age of 31.5 ± 6.6 years and a mean follow-up of 11.6 ± 6.9 years. At the last follow-up, radiographic osteoarthritis (OA) ranged from 36% to 76%, with an average rate of 48 ± 19%; functional scores ranged from 71 to 97, with a mean of 90 ± 4 for the Lysholm score, 86 ± 10 for the International Knee Documentation Committee (IKDC) and 94 ± 16 for the knee injury and osteoarthritis outcome (KOOS). Twenty-one studies dealt with DL with a mean age of 49.9 ± 7.2 years and a mean follow-up of 14.9 ± 6.3 years. At the last follow-up, radiographic OA ranged from 23% to 97%, with an average rate of 77 ± 28%; functional scores ranged from 40 to 87, with a mean of 79 ± 10 for the Lysholm score and 71 ± 16 for the IKDC.

CONCLUSION

Ten-year clinical outcomes of APM are better for TTs when compared to DLs. Rates of OA are difficult to compare but lower for TTs.

LEVEL OF EVIDENCE

Level IV.

Arthroscopic meniscal surgery in Norway from 2010 to 2020: A paradigmatic shift

Purpose

Meniscal injuries in the knee are usually treated surgically with arthroscopic partial resection (APR) or arthroscopic repair (AR). APR has been shown to increase the risk of osteoarthritis and the focus has shifted to repairing the meniscus with AR. The extent of this shift is yet to be established and an analysis of incidence rates (IR) of APR and AR for meniscal injuries could highlight this.

Methods

Data from the Norwegian Patient Registry (NPR) and Statistics Norway (SN) from 2010 to 2020 were collected. The number of procedures, demographics and facilities providing meniscal surgery were obtained from NPR, while population size and catchment area were collected from SN. IR of APR and AR and APR/AR rate ratios were estimated and compared.

Results

A total of 119,528 knee arthroscopies were performed, 89.6% of which were APR. The number of APR performed nationally decreased by 72%, while AR procedures increased by 178%. The national IR of APR decreased from 298 to 82/100,000 inhabitants (p < 0.001). For AR, the national IR increased annually from 13/100,000 inhabitants to a peak in 2019 of 32/100,000 inhabitants (p < 0.001). The APR/AR rate ratio decreased from 22 to below five and the APR/AR trend curves showed a statistically significant decrease (p < 0.001).

Conclusion

Surgical treatment of meniscal injuries has changed, with a substantial reduction in APR and a strong increase in AR. The reduction in APR, especially in older patients, suggests that meniscal surgery in Norway has undergone a paradigmatic shift, in line with recent literature.

Level of Evidence

Level IV.

Meniscus-Related Videos on TikTok Are Widely Viewed and Shared but the Educational Quality for Patients Is Poor

Purpose

To evaluate the quality of meniscus-related TikTok videos to better understand their value for patient education.

Methods

The term "meniscus" was used as the key word for an extensive online search of video content on the TikTok on November 14, 2023. The first 100 videos were used for analysis. The duration of the videos and the number of likes, shares, and views were recorded for each video. Furthermore, videos were categorized based on the source (health workers, private user), the type of subject (patient experience, physical therapy, anatomy, clinical examination, surgical technique and injury mechanism), type of content (patient experience/testimony, education, rehabilitation), and the presence of music or voice. The quality and reliability assessments of video contents were conducted using the DISCERN instrument, the Journal of the American Medical Association benchmark criteria, and Global Quality Score.

Results

Of the 100 videos included in this study, 62 (62%) videos were published by health workers and 38 by private users (38%). Most of the information regarded patient experience (36, 36%), followed by physical therapy (32, 32%), anatomy (14, 14%), clinical examination (8, 8%), surgical technique (6, 6%), and injury mechanism (4, 4%). Video content reported patient experience in 39 (39%) videos, rehabilitation in 31 (31%) videos, and education in the remaining 30 (30%). The mean length of the videos was 39.12 ± 49.56 seconds. The mean number of views was 1,383,001.65 ± 5,291,822.28, whereas the mean numbers of comments, likes and shares were 408.53 ± 1976.90, 54,763.43 ± 211,823.44 and 873.70 ± 2,802.01, respectively. The mean DISCERN score, Journal of the American Medical Association benchmark criteria score, and Global Quality Score were 17.93 ± 5.07, 0.24 ± 0.47, and 1.15 ± 0.41, respectively.

Conclusions

Meniscus-related videos on TikTok are widely viewed and shared but the overall educational value to patients is poor.

Clinical Relevance

As patients increasingly use social media to learn about their conditions, it is important for orthopaedic health care professionals to understand the limitations of TikTok videos addressing the meniscus as potential sources of information for their patients.

High failure rate after medial meniscus bucket handle tears repair in the stable knee

BACKGROUND

It is nowadays recommended to "Save the meniscus". This paradigm is based on the affirmation that an extended meniscectomy exposes to the risk of long-term secondary osteoarthritis and the global failure rate of a longitudinal tear repair remains low, whether it is the medial or lateral meniscus, with or without anterior cruciate ligament (ACL) reconstruction. However, each kind of lesion has to be studied separate.

PURPOSE

The study aimed to focus on a homogeneous population of isolated repair of the bucket handle tear (BHT) of the medial meniscus (MM) in patients with stable knees to evaluate failure rate at a minimum of three years of follow-up. The secondary objectives were to evaluate any risk factors or protective factors of failure, clinical outcomes, and secondary amount of meniscectomy in failure cases compared to the amount of meniscus fixed in the first surgery.

METHODS

All patients who underwent arthroscopic repair of a BHT of the MM situated in the red-on-red or red-on white (RW) zone on a stable knee between January 2010 and December 2018 were evaluated retrospectively. Failure was defined as a need for reoperation for recurrence of meniscal symptoms (pain, locking) on the medial side with per-operative confirmation of the absence of healing. The following parameters were studied: demographics (age, gender, BMI), time from injury to surgery, clinical scores (Tegner, Lysholm, International Knee Documentation Committee [IKDC]), surgical findings (extent and zone of the tear), surgical management (number and type of suture).

RESULTS

Thirty-nine patients were included. The mean follow-up was 77.2±24.4 [36-141] months. Twenty-seven (69%) failures were recorded. In 56% (15/27) of the reoperations, the meniscectomy amount was smaller than what it would have been done in the first surgery. All clinical scores improved significantly from pre- to post-operatively; all patients met minimal clinically important differences for all the scores. No risk factors were found significant in the multivariate analysis.

CONCLUSION

Repairing an isolated BHT of the MM is associated with a high failure rate. Despite the failure, we observed that the meniscectomy area was smaller than documented in the primary surgery in most of the cases and repair must still be considered as the first option.

LEVEL OF EVIDENCE

IV; retrospective cohort series.

Quantitative Magnetic Resonance Imaging of Lateral Compartment Articular Cartilage After Lateral Extra-articular Tenodesis

BACKGROUND

Concerns have arisen that anterior cruciate ligament reconstruction (ACLR) with lateral extra-articular tenodesis (LET) may accelerate the development of posttraumatic osteoarthritis in the lateral compartment of the knee.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate whether the augmentation of ACLR with LET affects the quality of lateral compartment articular cartilage on magnetic resonance imaging (MRI) at 2 years postoperatively. We hypothesized that there would be no difference in T1rho and T2 relaxation times when comparing ACLR alone with ACLR + LET.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A consecutive subgroup of patients at the Fowler Kennedy Sport Medicine Clinic participating in the STABILITY 1 Study underwent bilateral 3-T MRI at 2 years after surgery. The primary outcome was T1rho and T2 relaxation times. Articular cartilage in the lateral compartment was manually segmented into 3 regions of the tibia (lateral tibia [LT]-1 to LT-3) and 5 regions of the femur (lateral femoral condyle [LFC]-1 to LFC-5). Analysis of covariance was used to compare relaxation times between groups, adjusted for lateral meniscal tears and treatment, cartilage and bone marrow lesions, contralateral relaxation times, and time since surgery. Semiquantitative MRI scores according to the Anterior Cruciate Ligament OsteoArthritis Score were compared between groups. Correlations were used to determine the association between secondary outcomes (including results of the International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, Lower Extremity Functional Scale, 4-Item Pain Intensity Measure, hop tests, and isokinetic quadriceps and hamstring strength tests) and cartilage relaxation.

RESULTS

A total of 95 participants (44 ACLR alone, 51 ACLR + LET) with a mean age of 18.8 years (61.1% female [58/95]) underwent 2-year MRI (range, 20-36 months). T1rho relaxation times were significantly elevated for the ACLR + LET group in LT-1 (37.3 ± 0.7 ms vs 34.1 ± 0.8 ms, respectively; P = .005) and LFC-2 (43.9 ± 0.9 ms vs 40.2 ± 1.0 ms, respectively; P = .008) compared with the ACLR alone group. T2 relaxation times were significantly elevated for the ACLR + LET group in LFC-1 (51.2 ± 0.7 ms vs 49.1 ± 0.7 ms, respectively; P = .03) and LFC-4 (45.9 ± 0.5 ms vs 44.2 ± 0.6 ms, respectively; P = .04) compared with the ACLR alone group. All effect sizes were small to medium. There was no difference in Anterior Cruciate Ligament OsteoArthritis Scores between groups (P = .99). Weak negative associations (rs = -0.27 to -0.22; P < .05) were found between relaxation times and quadriceps and hamstring strength in the anterolateral knee, while all other correlations were nonsignificant (P > .05).

CONCLUSION

Increased relaxation times demonstrating small to medium effect sizes suggested early biochemical changes in articular cartilage of the anterolateral compartment in the ACLR + LET group compared with the ACLR alone group. Further evidence and long-term follow-up are needed to better understand the association between these results and the potential risk of the development of osteoarthritis in our patient cohort.

All-Inside Arthroscopic Meniscus Repair for Patients Over 40 Years of Age: Is Forty the New Twenty?

INTRODUCTION

Meniscal injuries are a common challenge in orthopedic surgery. For decades, partial or total meniscectomy has been the primary surgical treatment for meniscal tears. In recent years, the increased recognition of menisci's biomechanical importance has progressively shifted the paradigm towards meniscus repair. However, meniscus-sparing surgery remains the treatment of choice for selected lesions in young and active patients, especially for young and active patients. In this study, we evaluated the effectiveness of all-inside sutures in treating meniscus tears in patients over 40.

METHODS

In our retrospective evaluation, we evaluated the clinical and functional outcomes of cases over 40 years of age with post-traumatic acute meniscus tears that received meniscus repairs using the all-inside technique. The pre-operative and post-operative functionality of treated patients were assessed using the knee injury and osteoarthritis outcome score (KOOS) score. Major complications were recorded.

RESULTS

Twenty-three cases met our inclusion criteria. Eight females and fifteen males with a mean age of 44.9 were included in our study. Their mean follow-up was 35.1 months. Before surgery, our patients' mean KOOS score was 55.4 (18-80). At the patients' latest follow-up, the value had risen to 87.4 (63-100). There was no statistical correlation between patients' age and their functional recovery. No surgical failure was recorded at the latest follow-up.

CONCLUSION

The all-inside suture technique can represent a suitable and reliable solution for suturable meniscal tears, even for patients over 40. Preserving the meniscus and restoring patients' functionality allows patients to return to their daily activities and promote their quality of life.

Could a three-dimensional contralateral meniscus segmentation for allograft or scaffold sizing be possible? A prospective study

PURPOSE

Meniscal allografts and biodegradable meniscal implants are attractive surgical options for painful subtotal or total meniscectomies. In order to get the best results, these should be as similar as possible to the original meniscus in terms of shape, structure, and volume. Three-dimensional meniscus sizing could be an approach to improve the accuracy of meniscus matching. Therefore, the aims of this study were to perform a comparative morphological and volumetric analysis of the healthy meniscus based on manual tri-planar segmentation and to demonstrate that the menisci from the contralateral knee could be used as a reference in the sizing of a meniscal graft or a scaffold.

METHODS

Three-dimensional meniscal models were created based on 120 MRIs in 60 healthy subjects (bilateral knees). The differences between the pairs of menisci concerning the widths, thicknesses, lateromedial distances, anteroposterior distances, angles of coverage, and meniscal volumes were evaluated. T-Student tests were used to compare the quantitative numerical variables of the different groups. Pearson's linear regression was used to determine if correlations existed between demographic variables (age, gender, height, weight) and anatomical parameters. Statistical significance was set at p < 0.05.

RESULTS

Comparing the 120 pairs of menisci of each subject, there was no statistically significant difference for all parameters studied for both the medial and lateral meniscus. When the measurements were stratified by gender, statistically significant differences were observed for all parameters except meniscal coverage angles. We observed that anteroposterior and lateromedial distances were positively correlated with height and body mass index both at the level of the medial meniscus (r = 0.68; r = 0.66; r = 0.65; and r = 0.63) and lateral (r = 0.68; r = 0.69; r = 0.61; and r = 0.60).

CONCLUSION

Our study demonstrated that the intra-individual 3D shapes of the left and right menisci are very similar. Therefore, the contralateral side could be used as a template for the 3D sizing of meniscal allografts or meniscal implants.

Clinical, Biomechanical, and Self-reported Health Status After ACL Reconstruction With Meniscal Repair in Soccer Players: Results at Minimum 1-Year Follow-up

BACKGROUND

Performing meniscal repair with anterior cruciate ligament reconstruction (ACLR) has been shown to contribute to the long-term preservation of knee health and gait biomechanics.

PURPOSE

To evaluate the role of meniscal repair in the performance of semiprofessional soccer players who returned to sport after ACLR.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

This study included 51 male soccer players (mean ± SD age, 28.82 ± 5.33 years) who underwent ACLR at a single institution between July 2018 and July 2019. The players were divided into 3 groups according to surgery type: ACLR only (n = 30), ACLR with lateral meniscal repair (n = 9), and ACLR with medial meniscal repair (n = 12). Outcomes were evaluated through clinical examination, self-reported health questionnaires (Cincinnati Knee Rating System, Tegner activity score, Tegner Lysholm Knee Scoring Scale, Tampa Scale of Kinesiophobia, and ACL-Return to Sport After Injury), and biomechanical performance evaluations (balance, strength, coordination, and symmetry tests). Parametric and nonparametric tests were carried out for multiple comparisons.

RESULTS

The mean ± SD follow-up time was 20.75 ± 9.38 months. Although no significant differences emerged in clinical and self-reported health status, almost all the physical parameters tested resulted in lower performance in players treated with ACLR and meniscal repair. Moreover, patients with ACLR with lateral meniscal repair reported higher pain and fear of reinjury, with lower outcomes in terms of strength, symmetry, and coordination as compared with the other 2 groups. Balance abilities were significantly affected in players who underwent meniscal repair as compared with those who underwent ACLR only.

CONCLUSION

The findings showed that biomechanical performance measures and fear of reinjury were significantly worse in soccer players with associated meniscal repair at a minimum 1-year follow-up, especially in those with a lateral meniscal tear.

Evaluation of the changes in incidence and patient age of knee arthroscopy along with changes in time between knee arthroscopy and arthroplasty between 1998 and 2018: a nationwide register study

BACKGROUND

Recent evidence has led to guidelines to refrain from recommending knee arthroscopy for patients with an osteoarthritis diagnosis. The aim of this study was to evaluate the latest changes in the incidence of arthroscopic surgery for degenerative knee disease, changes in the ages of those patients and the delay between knee arthroscopy and arthroplasty, in Finland between 1998 and 2018.

METHOD

The data for were collected from the Finnish National Hospital Discharge Register (NHDR). All knee arthroplasties and arthroscopies performed due to osteoarthritis, degenerative meniscal tears, and traumatic meniscal tears were included. Incidence rates (per 100,000 person-years) as well as the median age of patients were calculated.

RESULTS

The incidence of arthroscopy decreased 74% (413 to 106 per 100,000 person-years) and knee arthroplasty increased 179% (94 to 262 per 100,000 person-years) between 1998 and 2018. The incidence of all arthroscopies increased until 2006. Subsequently, the incidence of arthroscopy due to OA decreased by 91% and arthroscopic partial meniscectomy (APM) for degenerative meniscal tears decreased by 77% until 2018. The decrease of traumatic meniscal tears begun later, leading to decrease of 57% between 2011 and 2018. Conversely, the incidence of patients undergoing APM of traumatic meniscal tear increased 375%. The median age of patients who underwent knee arthroscopy decreased from 51 to 46 and from 71 to 69 in knee arthroplasty patients.

CONCLUSIONS

Increasing evidence that recommends refraining from knee arthroscopy in OA and degenerative meniscal tears has led to a dramatic decrease in the incidence of arthroscopies. Simultaneously, the median age of the patients who undergo these operations has continued to decrease.

Unplanned return to the operating room after arthroscopic procedures: a need to consider 12 months after the initial surgery

INTRODUCTION

The purpose of this study was to report the proportion and cause of unplanned revision surgery rates within 1 year following arthroscopic procedures. Our hypothesis was that there is a significant rate of unplanned returns (URs) occurring between 3 and 12 months after the initial procedure and that causes of revision are different when considering the delay after the index surgery.

MATERIALS AND METHODS

Among 4142 consecutive patients who underwent an arthroscopic procedure in a single department of orthopedics and traumatology, patients undergoing revision surgery for any reasons directly related to the primary procedure were included. Cause for revision, surgical site, delay from index procedure, and number of revisions were screened.

RESULTS

Seventy-eight patients underwent 97 revision surgeries (2.3%) for reasons directly related to the primary procedure. Most revision surgeries were performed after month 3 following index surgery (59 patients, 60.8%). Mean time to revision surgery was 5.3 ± 4.3 months (range 0-365 days). Usual early-onset (< 3 months) reasons for unplanned revision were surgical site infection (17 patients, 0.41%), wound-healing defect (12 patients, 0.29%), and hemorrhagic complication (7 patients, 0.17%). Reasons for delayed unplanned revision (> 3 months) were index procedure failure (21 patients, 0.51%), stiffness (18 patients, 0.43%), and removal of hardware (16 patients, 0.41%).

CONCLUSIONS

Reasons for return to the operating room (OR) are different depending on the timepoint from index procedure. Patients should receive relevant information accordingly when scheduling any arthroscopic procedure, including up to 1-year potential complications.

LEVEL OF EVIDENCE

Prognostic study, Case series, Level IV.

Does laterality matter? a systematic review and meta-analysis of clinical and survival outcomes of medial versus lateral meniscal scaffolds

PURPOSE

Meniscal scaffold implants have gained interestas a therapeutic alternative for irreparable partial meniscal defects and post-meniscectomy syndrome. However, the effect of laterality on outcomes is unclear. This study aimsto assess the hypothesis that lateral meniscal scaffold implants have worse clinical or survival outcomes compared with medial scaffold implants.

METHODS

The study was performedaccording to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and registered with PROSPERO. Three databases (PubMed, Embase, Scopus) were searched from date of database establishment to 21 January 2022. Human studies reporting clinical or survival outcomedata specific to the medial or lateral meniscal scaffold implant were included. Random-effects model was used to analyse survival outcome data.

RESULTS

Ten studies comprising 568 patients (mean age 29.2-40 years, follow up duration 1-14 years) were included. There were 483 medial and 85 lateral meniscal scaffold implants. Amongst two studies directly comparing the survival rate of medial and lateral meniscal scaffolds, there was no significant difference in survival rates between medial and lateral meniscus scaffolds (hazard ratio = 1.24, 95 % confidence interval: 0.51-3.03, P = 0.63). There were no consistent statistically significant differences between medial and lateral meniscal scaffolds in terms of postoperative Visual Analog Scale pain,Tegner Activity, Lysholm, International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome, and Knee Society Scores.

CONCLUSION

Despite anatomical and biomechanical differences between the medial and lateral meniscus, there are no significant differences in clinical outcomes or survival rates between medial and lateral meniscal scaffold implants for irreparable partial meniscal defects at short- or mid-term follow up. Lateral meniscal scaffold implants are therefore non-inferior to medial meniscal scaffold implants.

Ipsilateral chondral lesions worsen the long-term prognosis following arthroscopic partial medial meniscectomy

PURPOSE

The effect of knee cartilage defects that are detected during partial meniscectomy remains controversial in terms of the long-term prognosis on knee function. This study aimed to investigate the effect of concurrent medial compartment focal cartilage lesions on the long-term prognosis of knee function in patients who underwent arthroscopic partial medial meniscectomy for traumatic medial meniscal tears.

METHODS

This retrospective study analyzed 46 patients who underwent arthroscopic partial medial meniscectomy between 1991 and 2008 by a single surgeon. Twenty-one patients who underwent arthroscopic partial medial meniscectomy due to traumatic meniscal tear had focal chondral lesions only at the medial compartment, and these patients were assigned to group A. Twenty-five patients who had no cartilage lesions in any compartments were assigned to group B. The age, sex, body mass index (BMI), follow-up time, age at the time of surgery, clinical and radiological scores, and perioperative arthroscopy findings were analyzed.

RESULTS

The mean follow-up time was 20 ± 3.7 years. No significant difference was found in the demographic data, and the average age of the patients at the time of operation was 35 ± 9.5 years. Both groups had improved Lysholm score at the last follow-up. Although no difference was found between the groups during the preoperative period, group B had a higher Lysholm score at the last follow-up than group A. The mean International Knee Documentation Committee (IKDC) and Knee injury and Osteoarthritis Outcome Score (KOOS) scores at the last follow-up were significantly higher in group B. The mean Kellgren-Lawrence grades in the operated knees of group A were higher than those of group B. In group A, a negative correlation was found between the BMI and postoperative Lysholm (r =  - 0.461, p = 0.03) IKDC (r =  - 0.433, p = 0.05) and KOOS (r =  - 0.565, p = 0.008) scores. In group B, no correlation was found between BMI and any score.

CONCLUSION

Among patients who underwent arthroscopic partial medial meniscectomy with an average follow-up of 20 years, those with concurrent focal cartilage defect in the medial compartment had clinically and radiologically worse outcomes than patients without any cartilage defect. Therefore, orthopedic surgeons should be meticulous before performing any arthroscopic partial medial meniscectomy in case of concurrent cartilage lesion.

LEVEL OF EVIDENCE

Level III.

Return to sports after ACL injury 5 years from now: 10 things we must do

Background

The outcome after ACL reconstruction (ACLR) is in general disappointing with unacceptable number of athletes that do not return to pre-injury level of sports, high re-injury rates, early development of osteoarthritis and shorter careers. Athletes after ACLR have high expectation to return to sports which is in contrast with the current outcomes. The aim of this manuscript is to present an overview of factors that are needed to be incorporated and to personalize the rehabilitation process for an athlete who has undergone an ACLR.

Level of evidence

4.

The crevice sign: a new indicator of meniscal instability in ACL reconstructions

PURPOSE

Meniscus preservation is key in knee surgery. The newly documented crevice sign indicates instability of the medial meniscus in ACL-deficient knees. Once the sign is visualised, it is imperative that the stability of the medial meniscus is assessed and potentially treated. It was hypothesized that there would be a strong correlation between the presence of an unstable medial meniscal tear in patients with the crevice sign in ACL-deficient knees.

METHODS

This was a multicenter prospective study carried out to evaluate the incidence of medial meniscal tears in patients with ACL-deficient knees and their correlation with a crevice sign. All patients (128) who had undergone ACL reconstruction between May 2020 and November 2020 were assessed arthroscopically for meniscal stability and divided in to two groups: stable (n = 84) and unstable (n = 44). Thereafter, the presence of the crevice sign was determined in each case.

RESULTS

The populations were comparable in terms of sex and age (Table 1). Fisher's exact test showed a significant association between the presence of the crevice sign and the instability of the medial meniscus (p < 0.001). Descriptive statistics suggest that the presence of crevice sign was associated more frequently to MM instability (38.6% vs 1.2%; p < 0.001). The specificity of this test was 98.8% and its sensitivity was 38.6%. The positive predictive value (PPV) was 94.4% and the negative predictive value (NPV) was 75.5%. Table 1 Descriptions and comparisons of internal meniscus instability of patients by presence of crevice sign Internal meniscus instability (N = 44) Internal meniscus stability (N = 84) Total (N = 128) Gender  N 44 84 128   Male 33 (75.0) 58 (69.0) 91 (71.1)   Female 11 (25.0) 26 (31.0) 37 (28.9) Fisher's exact test (n.s.) Age (years)  N 44 84 128   Mean (ET) 28.6 (9.4) 30.1 (10.2) 29.6 (9.9)   Median (IIQ) 26.5 (22.0;34.5) 27.0 (22.5;37.0) 27.0 (22.0;36.0)   [Min-Max] [14-54] [14-52] [14-54] Wilcoxon test bilateral (n.s.) Crevice sign  N 44 84 128   Absent 27 (61.4) 83 (98.8) 110 (85.9)   Present 17 (38.6) 1 (1.2) 18 (14.1) Fisher's exact test p < 0.001 CONCLUSION: The hypothesis was confirmed since medial meniscal instability was strongly correlated with the existence of the crevice sign and showed high specificity and PPV.

LEVEL OF EVIDENCE

III.

A longer duration from injury to surgery is associated with preoperative deterioration of an isolated meniscal tear in patients aged 40 years or older

PURPOSE

To evaluate the preoperative deterioration of an isolated meniscal tear in patients aged 40 years or older, and whether time from injury to surgery is associated with worsening of a meniscal tear.

METHODS

Patients aged 40 years or older who underwent arthroscopic surgery for isolated meniscal tear between 2014 and 2019 were retrospectively reviewed. The diagnostic magnetic resonance imaging (MRI) findings and arthroscopic findings were compared to evaluate the deterioration of meniscal tears. Predictors of the development of meniscal tears; patient demographic factors, duration from injury to surgery (injury to MRI and MRI to surgery), and image findings were assessed.

RESULTS

A total of 58 patients (58 knees) were included (mean age, 55.9 ± 8.5 years; male/female, 31/27). An isolated meniscal tear deteriorated in 28 (48.3%). Compared patients with and without deteriorated meniscal tear, significant differences were found in the MRI grade of meniscal tear (p = 0.03), duration from injury to MRI (164.2 ± 167.9 vs 45.2 ± 48.7 days, p < 0.001), and from MRI to surgery (148.8 ± 91.1 vs 67.6 ± 56.7 days, p < 0.001). A multivariate regression analysis showed that the duration from injury to MRI (odds ratio [OR], 1.03; p < 0.001) and from MRI to surgery (OR, 1.02; p < 0.001) were independent predictors.

CONCLUSION

Approximately 50% of isolated meniscal tears deteriorated preoperatively in patients aged 40 years or older. The duration from injury to surgery was an independent predictor of worsening of an isolated meniscal tear.

Current Concepts on Tissue Adhesive Use for Meniscal Repair-We Are Not There Yet: A Systematic Review of the Literature

BACKGROUND

Tissue adhesives (TAs) represent a promising alternative or augmentation method to conventional tissue repair techniques. In sports medicine, TA use has been suggested and implemented in the treatment of meniscal tears. The aim of this review was to present and discuss the current evidence and base of knowledge regarding the clinical usage of TAs for meniscal repair.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic literature search was performed using the PubMed, Embase, and Cochrane Library databases for studies reporting on clinical outcomes of TA usage for meniscal repair in humans in the English language published before January 2020.

RESULTS

Ten studies were eligible for review and included 352 meniscal repairs: 94 (27%) were TA-based repairs and 258 (73%) were combined suture and TA repairs. Concomitant anterior cruciate ligament reconstruction was performed in 224 repairs (64%). All included studies utilized fibrin-based TA. Of the 10 studies, 9 were evidence level 4 (case series), and 8 reported on a cohort of ≤40 meniscal repairs. Rates of meniscal healing were evaluated in 9 of 10 studies, with repair failure seen in 39 repairs (11%).

CONCLUSION

The use of TAs, specifically fibrin-based TAs, for meniscal repair shows good results as either an augmentation or primary repair of various configurations of meniscal tears. However, this review reveals an absence of comparative high-quality evidence supporting the routine use of TAs for meniscal repair and emphasizes the lack of an ideal TA designed for that purpose. Further high-quality research, basic science and clinical, will facilitate the development of new materials and enable testing their suitability for use in meniscal repair.

Knee Joint Menisci Are Shock Absorbers: A Biomechanical In-Vitro Study on Porcine Stifle Joints

The aim of this biomechanical in vitro study was to answer the question whether the meniscus acts as a shock absorber in the knee joint or not. The soft tissue of fourteen porcine knee joints was removed, leaving the capsuloligamentous structures intact. The joints were mounted in 45° neutral knee flexion in a previously validated droptower setup. Six joints were exposed to an impact load of 3.54 J, and the resultant loss factor (η) was calculated. Then, the setup was modified to allow sinusoidal loading under dynamic mechanical analysis (DMA) conditions. The remaining eight knee joints were exposed to 10 frequencies ranging from 0.1 to 5 Hz at a static load of 1210 N and a superimposed sinusoidal load of 910 N (2.12 times body weight). Forces (F) and deformation (l) were continuously recorded, and the loss factor (tan δ) was calculated. For both experiments, four meniscus states (intact, medial posterior root avulsion, medial meniscectomy, and total lateral and medial meniscectomy) were investigated. During the droptower experiments, the intact state indicated a loss factor of η = 0.1. Except for the root avulsion state (−15%, p = 0.12), the loss factor decreased (p &lt; 0.046) up to 68% for the total meniscectomy state (p = 0.028) when compared to the intact state. Sinusoidal DMA testing revealed that knees with an intact meniscus had the highest loss factors, ranging from 0.10 to 0.15. Any surgical manipulation lowered the damping ability: Medial meniscectomy resulted in a reduction of 24%, while the resection of both menisci lowered tan δ by 18% compared to the intact state. This biomechanical in vitro study indicates that the shock-absorbing ability of a knee joint is lower when meniscal tissue is resected. In other words, the meniscus contributes to the shock absorption of the knee joint not only during impact loads, but also during sinusoidal loads. The findings may have an impact on the rehabilitation of young, meniscectomized patients who want to return to sports. Consequently, such patients are exposed to critical loads on the articular cartilage, especially when performing sports with recurring impact loads transmitted through the knee joint surfaces.

A Balanced Arthroscopic Debridement of the Inner Layer of the Knee Retinaculum Increases the Tibiofemoral Joint Space Width

INTRODUCTION

Traditional techniques can enlarge the medial tibiofemoral joint space width (JSW) for meniscal repairs, but a remnant ligament laxity may be developed. Alternatively, the debridement of the inner retinaculum layer may result in a balanced JSW without causing extra-ligament damage (retinaculum layers II and collateral ligament).

PURPOSE

The purpose of this study was to determine whether a concentric arthroscopic debridement of the inner retinaculum layer increases the tibiofemoral JSW in patients with meniscal injuries. Secondarily, we determine whether the increase in JSW is symmetrical between compartments and describe the rate of complications and patient satisfaction.

METHOD

Twenty middle-aged (15 male and five female) patients diagnosed with acute meniscal injury aged 36 ± 12 years were enrolled. The patients were submitted to an arthroscopic debridement of the inner layer of the knee retinaculum for both the medial and lateral compartments. The tibiofemoral JSW was measured intra-articularly using a custom instrument. A two-way ANOVA for repeated measures was used to compare the JSW. A Bland-Altman analysis and test-retest analysis were performed.

RESULTS

The JSW increased following the debridement of the inner retinaculum layer, for both the medial and lateral compartments (p < 0.001). No complications were identified, and the patients were satisfied with the intervention. The minimal detectable change and bias of the custom instrument were 0.06 mm and 0.02 mm, respectively.

CONCLUSION

The debridement allows a clinically important (>1 mm) symmetric tibiofemoral JSW enlargement. The technique suggests favoring the diagnosis of meniscus injuries and manipulating arthroscopic instruments without secondary complications after one year.

Meniscus regeneration by 3D printing technologies: Current advances and future perspectives

Meniscal tears are a frequent orthopedic injury commonly managed by conservative strategies to avoid osteoarthritis development descending from altered biomechanics. Among cutting-edge approaches in tissue engineering, 3D printing technologies are extremely promising guaranteeing for complex biomimetic architectures mimicking native tissues. Considering the anisotropic characteristics of the menisci, and the ability of printing over structural control, it descends the intriguing potential of such vanguard techniques to meet individual joints’ requirements within personalized medicine. This literature review provides a state-of-the-art on 3D printing for meniscus reconstruction. Experiences in printing materials/technologies, scaffold types, augmentation strategies, cellular conditioning have been compared/discussed; outcomes of pre-clinical studies allowed for further considerations. To date, translation to clinic of 3D printed meniscal devices is still a challenge: meniscus reconstruction is once again clear expression of how the integration of different expertise (e.g., anatomy, engineering, biomaterials science, cell biology, and medicine) is required to successfully address native tissues complexities.

Meniscectomy is still a frequent orthopedic procedure: a pending need for education on the meniscus treatment possibilities

PURPOSE

The purpose of this study was to evaluate the current status of education of polish surgeons in the subject of meniscus repair possibilities. The analysis of the possible correlations between the number of knee arthroscopy procedures performed by polish surgeons and their decision whether to remove or to repair the damaged meniscus has been performed.

METHODS

Two-hundred and five registered orthopedic surgeons took part in surveys. The questionnaire contained the description of 20 patients with different types of meniscus damage and three questions concerning the experience in knee arthroscopy (two questions) and a choice of the treatment method (one question). Comparisons were made between knee arthroscopy experts (> 100 arthroscopies performed per year) and non-experts (≤ 100 cases).

RESULTS

The questionnaire was completed by 194 knee surgeons from Poland with different levels in knee arthroscopy experience. For most cases, experts and non-experts agreed on the meniscus treatment method. Statistically significant differences in the recommended treatment between experts and non-experts were observed in 4 cases, where experts decided to repair the damage rather than to perform the meniscectomy.

CONCLUSIONS

Meniscectomy remains a frequent orthopedic procedure, despite meniscal sparing having been advocated for several decades now and despite the existence of meniscus repair technique which gives good clinical outcomes-augmentation of the damaged meniscus with a collagen membrane. Polish surgeons still need education on the meniscus treatment possibilities.

LEVEL OF EVIDENCE

V.

Effect of Concomitant Meniscal Lesions and Meniscal Surgery in ACL Reconstruction With 5-Year Follow-Up: A Nationwide Prospective Cohort Study From Norway and Sweden of 8408 Patients

Background

Increased knowledge of the factors predicting outcome after anterior cruciate ligament reconstruction (ACLR) is needed.

Purpose

To determine the effect of concomitant meniscal lesions, and the surgical management thereof, on patient-reported outcomes 5 years after ACLR.

Study Design

Prospective cohort study; Level of evidence, 2.

Methods

A total of 15,706 patients who underwent primary unilateral ACLR between 2005 and 2008 were enrolled prospectively and evaluated longitudinally. All patients were part of the Norwegian and Swedish national knee ligament registries. Outcomes at 5-year follow-up were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS). A multivariable linear regression model was used to assess possible effects on prognosis, as measured by KOOS, of a concomitant meniscal lesion and its associated surgical treatment.

Results

At a mean follow-up of 5.1 ± 0.2 years, KOOS data were available from 8408 patients: 4774 (57%) patients with no and 3634 (43%) patients with concomitant meniscal lesions (mean patient age, 33.8 ± 10.7 years). Patients with concomitant meniscal lesions reported equal crude mean scores compared with patients without meniscal lesions in all KOOS subscales 5 years after ACLR. The mean improvement in scores from preoperative to the 5-year follow-up was greater for patients with a concomitant meniscal lesion for the KOOS Pain, Activities of Daily Living (ADL), and Sport and Recreation subscales. In the adjusted regression analyses, using patients without concomitant meniscal lesions as the reference, neither no treatment nor resection or repair of medial meniscal lesions were significantly associated with KOOS scores 5 years after ACLR. Except for the ADL subscale, in which a repaired lateral meniscal lesion was associated with better outcome, no significant associations between any of the lateral meniscal lesion treatment categories and KOOS outcome at 5-year follow-up were identified.

Conclusion

Concomitant meniscal lesions at the time of ACLR conferred no negative effects on patient-reported outcomes 5 years after ACLR. The improvement in selected KOOS subscales from preoperative to the 5-year follow-up was significantly greater for patients with concomitant meniscal lesions than for patients without such lesions.

Meniscus Repair Techniques

The menisci play a vital role in maintaining knee function and protecting the chondral surfaces. Acute and chronic tears are common injuries among both young athletes and older patients with early degenerative changes. The progression of physiological derangement and chondral injury after meniscus injury and meniscectomy have prompted interest in expanding meniscus repair techniques. Recent literature encourages an attempt at repair in tear patterns previously declared irreparable if the tissue quality allows. The orthopedic surgeon should understand the multitude of techniques available to them and be prepared to combine techniques to optimize the quality of their repair construct. While biological augmentation may show some promising early results, the quality of the current data precludes strong recommendations in their favor.

Extracellular vesicles derived from mesenchymal stromal cells mediate endogenous cell growth and migration via the CXCL5 and CXCL6/CXCR2 axes and repair menisci

Background

Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) are promising candidates for tissue regeneration therapy. However, the therapeutic efficacy of MSC-EVs for meniscus regeneration is uncertain, and the mechanisms underlying MSC-EV-mediated tissue regeneration have not been fully elucidated. The aims of this study were to evaluate the therapeutic efficacy of intra-articular MSC-EV injection in a meniscus defect model and elucidate the mechanism underlying MSC-EV-mediated tissue regeneration via combined bioinformatic analyses.

Methods

MSC-EVs were isolated from human synovial MSC culture supernatants via ultrafiltration. To evaluate the meniscus regeneration ability, MSC-EVs were injected intra-articularly in the mouse meniscus defect model immediately after meniscus resection and weekly thereafter. After 1 and 3 weeks, their knees were excised for histological and immunohistochemical evaluations. To investigate the mechanisms through which MSC-EVs accelerate meniscus regeneration, cell growth, migration, and chondrogenesis assays were performed using treated and untreated chondrocytes and synovial MSCs with or without MSC-EVs. RNA sequencing assessed the gene expression profile of chondrocytes stimulated by MSC-EVs. Antagonists of the human chemokine CXCR2 receptor (SB265610) were used to determine the role of CXCR2 on chondrocyte cell growth and migration induced by MSC-EVs.

Results

In the meniscus defect model, MSC-EV injection accelerated meniscus regeneration and normalized the morphology and composition of the repaired tissue. MSC-EVs stimulated chondrocyte and synovial MSC cell growth and migration. RNA sequencing revealed that MSC-EVs induced 168 differentially expressed genes in the chondrocytes and significantly upregulated CXCL5 and CXCL6 in chondrocytes and synovial MSCs. Suppression of CXCL5 and CXCL6 and antagonism of the CXCR2 receptor binding CXCL5 and CXCL6 negated the influence of MSC-EVs on chondrocyte cell growth and migration.

Conclusions

Intra-articular MSC-EV administration repaired meniscus defects and augmented chondrocyte and synovial MSC cell growth and migration. Comprehensive transcriptome/RNA sequencing data confirmed that MSC-EVs upregulated CXCL5 and CXCL6 in chondrocytes and mediated the cell growth and migration of these cells via the CXCR2 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02481-9.

Meniscal repair: The current state and recent advances in augmentation

Meniscal injuries represent one of the most common orthopedic injuries. The most frequent treatment is partial resection of the meniscus, or meniscectomy, which can affect joint mechanics and health. For this reason, the field has shifted gradually towards suture repair, with the intent of preservation of the tissue. "Save the Meniscus" is now a prolific theme in the field; however, meniscal repair can be challenging and ineffective in many scenarios. The objectives of this review are to present the current state of surgical management of meniscal injuries and to explore current approaches being developed to enhance meniscal repair. Through a systematic literature review, we identified meniscal tear classifications and prevalence, approaches being used to improve meniscal repair, and biological- and material-based systems being developed to promote meniscal healing. We found that biologic augmentation typically aims to improve cellular incorporation to the wound site, vascularization in the inner zones, matrix deposition, and inflammatory relief. Furthermore, materials can be used, both with and without contained biologics, to further support matrix deposition and tear integration, and novel tissue adhesives may provide the mechanical integrity that the meniscus requires. Altogether, evaluation of these approaches in relevant in vitro and in vivo models provides new insights into the mechanisms needed to salvage meniscal tissue, and along with regulatory considerations, may justify translation to the clinic. With the need to restore long-term function to injured menisci, biologists, engineers, and clinicians are developing novel approaches to enhance the future of robust and consistent meniscal reparative techniques.

All-Inside Arthroscopic Repair For Longitudinal Meniscal Tears: Clinical and Functional Results

Meniscal injuries are a common challenge in orthopaedic surgery. Depending on their location and the patient's age and functional needs, they can be treated either conservatively or surgically. A surgical approach can consist of arthroscopic meniscectomy or meniscal suture. The latter is the treatment of choice in case of lesions involving the red-red or red-white areas of the meniscus, especially for young high-demanding patients. We report here our experience with the repair of longitudinal meniscal tears using the all-inside technique with the Fast-Fix™ 360 Meniscal Repair System (Smith & Nephew Endoscopy, Andover, MA). We retrospectively evaluated 20 consecutive cases of longitudinal meniscal tears. In 4 cases, concomitant ACL rupture was diagnosed and treated alongside the meniscal repair. All patients underwent periodic clinical evaluations. At the latest check-up, their functional outcomes were rated according to the Tegner-Lysholm Knee and KOOS scoring scales. The mean Tegner-Lysholm Knee score was 84.85 (44-100) and the mean KOOS score was 88.58. No failure or major complications were observed. Furthermore, a negative statistical association was observed between age at surgery and the post-operative Tegner-Lysholm Knee score (coef. = -1.01189 [-1.942073,-0.0817063], p = 0.035). This relation, independent of gender, meniscus involved, eventual associated ACL reconstruction, and chondral injury, suggests that functional outcomes worsen with increasing patient age. Our results suggest that the arthroscopic all-inside suture is both safe and effective in cases of longitudinal meniscal tear, considering the good post-operative functionality and low rates of local complications and surgical failures.

Outcomes at 20 Years After Meniscectomy in Patients Aged 50 to 70 Years

PURPOSE

To report the outcomes of arthroscopic meniscectomy (AM) at 20 years of follow-up through timing/rate of conversion to total knee replacement (TKR) and Knee Injury and Osteoarthritis Outcome Score (KOOS), focusing on detection of specific predictor variables for these outcomes, in patients 50 to 70 years old.

METHODS

We performed a retrospective study of 289 patients, ages at surgery 50 to 70 years, with diagnosis of degenerative meniscal tear who underwent arthroscopic meniscectomy. We collected the following baseline data: age, sex, injured meniscus (medial, lateral, or both), knee alignment, osteoarthritis (OA), associated lesion identified during arthroscopy, and associated procedure performed during arthroscopy. At 20 years of follow-up, we collected rate and timing of TKR conversion, and we evaluated clinical outcomes with KOOS.

RESULTS

Female sex (P < .01), older age (P < .01), lateral meniscectomy (P = .02), malalignment (P = .03), and advanced chondral lesion (P < .01) were found to be significantly related to subsequent TKR. No significant correlation was found between amount of resection and subsequent TKR (P = .26). Negative predictor factors to obtain equal or superior to age- and sex-adjusted KOOS scores were age 60 to 70 years at time of AM (P = .03) and lateral meniscectomy (P = .02).

CONCLUSIONS

We report a 15.7% conversion rate at 20 years from AM to TKR and a mean time between surgeries of 7 years. Subsequent TKR in the 20 years after AM for degenerative meniscus tears were significantly associated with preoperative OA and chondral lesion (Kellgren Lawrence 2; Outerbridge >2), lateral meniscectomy, age at surgery, female sex, and malalignment. Furthermore, age >60 years, lateral meniscectomy, and concurrent anterior cruciate ligament reconstruction were negative predictors for poor clinical outcomes at 20 years. Therefore, if patients present with negative predictor factors, the AM should not be proposed as second-line treatment, and nonoperative management should be continued until TKR is unavoidable.

LEVEL OF EVIDENCE

IV, case series.

The future of meniscus science: international expert consensus

Purpose

The purpose of this study was to evaluate the main focus areas for research and development for furthering the state of meniscus science in 2021.

Methods

An electronic survey including 10 questions was sent in a blind fashion to the faculty members of the 5^th International Conference on Meniscus Science and Surgery. These faculty served as an expert consensus on the future of research and development areas of meniscus science. Survey responses were analyzed using descriptive statistics and ranking weighted averages were calculated to score survey questions.

Results

Of the 82 faculty, 76 (93%) from 18 different countries completed the survey (84% male, 16% female). The highest ranked future research and development focus areas were meniscus repair, biologics, osteotomy procedures, addressing meniscus extrusion, and the development of new therapies for the prevention of posttraumatic osteoarthritis. Currently, the most ‘valuable’ type of biologic reported for meniscus treatment was platelet-rich plasma. The main reported global research limitation was a lack of long-term clinical outcomes data. The most promising emerging medical technologies for improving meniscus science were 3-D printing, personalized medicine, and artificial implants.

Conclusions

This survey suggests that the future of meniscus science should be focused on meniscal preservation techniques through meniscus repair, addressing meniscal extrusion, and the use of orthobiologics. The lack of long-term clinical outcomes was the main reported research limitation globally for meniscus treatment. Future product development utilizing emerging medical technologies suggest the use of 3-D printing for meniscal transplants/scaffolds, personalized treatment, and bioengineering for artificial implants.

Level of Evidence

Level V.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-021-00345-y.

Outcomes at 20 years after meniscectomy in young patients

AIM

To define arthroscopic meniscectomy (AM) outcomes in young patients at 20 years follow up in terms of predictors of poor clinical results, rate and timing of conversion to total knee replacement (TKR).

METHODS

The following data were collected for 225 patients aged between 18 and 50 years with meniscal tear (MT) who underwent AM: age at surgery, gender, injured meniscus, knee alignment, associated lesions, amount of meniscal resection. At 20 years follow up, rate and timing of TKR conversion and clinical outcomes with Knee injury and Osteoarthritis Outcome Score (KOOS) score were reviewed.

RESULTS

Ten patients (4.4%) required TKR in the follow up period. The mean time from AM to TKR was 7.0 years (standard deviation 3.87). Age between 40 and 50 years at AM (P < 0.01), malalignment (P < 0.01), lateral meniscectomy (any size, P = 0.01), advanced chondral lesion (Outerbridge > 2, P < 0.01) and total meniscectomy (P < 0.01) were significantly related to subsequent TKR. Negative predicting factors to obtaining equal or superior to age/sex-adjusted KOOS score were age between 40 and 50 years old at time of AM (P < 0.01), female sex (P < 0.01), malalignment (P = 0.04), and advanced chondral lesion (Outerbridge > 2, P = 0.02).

CONCLUSIONS

Twenty years conversion rate to TKR after AM for MT is 4.4% and TKR was performed after a mean time of 7 years. Significant association between TKR surgery and advanced chondral lesion (Outerbridge > 2), total meniscectomy, lateral meniscectomy, age at surgery between 40 and 50 years old, and malalignment were found. Age between 40 and 50 years at time of AM, female, malalignment, advanced chondral lesion were all factors significantly related to poor clinical results.

Inside-out Repair of Extensive Meniscal Tears Using Posteromedial and Posterolateral Neurovascular Protective Windows

Three popular repair techniques for preserving the torn meniscus are the all-inside, outside-in, and inside-out techniques. Among these, the inside-out technique has shown low failure rates, and it therefore remains the gold-standard technique for repairing the torn meniscus. For extensive and chronic meniscal tears, proper use of this technique has become fundamental for knee surgeons. Nevertheless, challenges in using this technique include a higher risk of catching the neurovascular bundles on the posteromedial and posterolateral sides of the knee and difficulties in reducing and stabilizing chronically displaced meniscal fragments. In this article, the inside-out technique is revisited with an emphasis on anatomic details of how to avoid the neurovascular bundles while addressing extensive and chronic meniscal lesions.

Circumferential-Surrounding ("Sandwich") Meniscal Repair: A Salvage Technique to Save the Meniscus

Meniscal injuries are extremely common in the general and athletic populations. The management strategy has switched from meniscectomy to meniscal-preserving techniques. It is nowadays extensively accepted that surgeons have to do their best to repair the meniscus and try to preserve as much tissue as possible. However, in many cases the tissue quality is poor and the tear pattern is complex. In such scenarios, meniscal repair has a lower success rate. In the present surgical technique, an arthroscopic all-inside circumferential-surrounding meniscal repair technique is presented. Any meniscal tissue or the meniscal rim is first debrided to a bleeding bed. Then, an all-inside device is used to create vertical sutures from capsule to capsule surrounding the entire meniscus (circumferential-surrounding). Care should be taken not to tighten the suture too much to avoid cutting the meniscal tissue. This easy and effective repair technique "packs" the meniscal tear fragments altogether and allows the surgeon to save the meniscus when facing with irreparable, degenerative, complex meniscus tears.

Polyurethane Meniscal Scaffold for the Treatment of Partial Meniscal Deficiency: 5-Year Follow-up Outcomes: A European Multicentric Study

BACKGROUND

A biodegradable polyurethane scaffold was developed to treat patients with the challenging clinical condition of painful partial meniscal defects.

HYPOTHESIS

The use of an acellular polyurethane scaffold in patients with symptomatic partial meniscal defects would result in both midterm pain relief and improved function.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 155 patients with symptomatic partial meniscal defects (101 medial and 54 lateral) were implanted with a polyurethane scaffold in a prospective, single-arm, multicentric study with a minimum 5-year follow-up. Clinical outcomes were measured with the visual analog scale for pain, International Knee Documentation Committee subjective knee evaluation form, Lysholm knee scale, and Knee injury and Osteoarthritis Outcome Score at baseline and at 2- and 5-year follow-ups. Magnetic resonance imaging (MRI) was used to evaluate the knee joint, meniscal implant, and meniscal extrusion. Kaplan-Meier survival analysis was also performed. Removal of the scaffold, conversion to a meniscal transplant, and unicompartmental/total knee arthroplasty were used as endpoints.

RESULTS

Eighteen patients were lost to follow-up (11.6%). The patients who were included in this study showed significant clinical improvement after surgery as indicated by the different outcome measures (P = .01). However, the clinical improvement tended to stabilize between 2 and 5 years of follow-up. MRI scans of the scaffolds in 56 patients showed a smaller-sized implant in the majority of the cases when compared with the native meniscus with an irregular surface at the 5-year follow-up. During the follow-up period, 87.6% of the implants survived in this study. At 5 years of follow-up, 87.9% of the medial scaffolds were still functioning versus 86.9% of the lateral scaffolds. In total, 23 treatments had failed: 10 removed scaffolds because of breakage, 7 conversions to meniscal allograft transplantation, 4 conversions to unicompartmental knee arthroplasty, and 2 conversions to total knee arthroplasty.

CONCLUSION

The polyurethane meniscal implant was able to improve knee joint function and reduce pain in patients with segmental meniscal deficiency over 5 years after implantation. The MRI appearance of this scaffold was different from the original meniscal tissue at the midterm follow-up. The treatment survival rates of 87.9% of the medial scaffolds and 86.9% of the lateral scaffolds in the present study compared favorably with those published concerning meniscal allograft transplantation after total meniscectomy.

Knee Arthroscopy: The "Crevice Sign," a New Pathognomonic Sign for Unstable Posterior Medial Meniscal Tear in Anterior Cruciate Ligament-Deficient Knees

There has been increased emphasis on medial meniscus repair in the anterior cruciate ligament-reconstructed knee, as this improves stability. We describe an arthroscopic sign of an unstable medial meniscal tear that is diagnostic. The "crevice sign" is a longitudinal fissure located on the distal medial femoral condyle. In the anterior cruciate ligament-deficient knee, there is increased strain on the medial meniscus. A posterior longitudinal medial meniscal tear can occur at the time of the index injury or with subsequent instability events. During this injury, the knee pivots and the anterior edge of the unstable medial meniscus digs into the articular cartilage of the medial femoral condyle, resulting in a longitudinal split of the distal femoral condyle articular cartilage. If this sign is observed during arthroscopy, it is recommended that surgeons thoroughly probe the medial meniscus to ensure no pathology is missed.