Clinical Outcomes of Inside-Out Meniscal Repair According to Anatomic Zone of the Meniscal Tear

The impact of smoking on meniscus surgery: a systematic review

Purpose

To provide a comprehensive, systematic review on the relationship and effects of smoking on clinical outcomes after meniscus surgery.

Methods

The following combination of keywords was entered into the electronic search engines: meniscus, meniscus repairs, meniscectomy, meniscal tear, meniscus excision AND (smoke OR smoking OR nicotine OR tobacco). The year of the study, country, type of study, number of subjects, medial/lateral/both menisci, body mass index, smoking status, mean age, gender, follow-up, type/pattern of injury, surgical implications and clinical outcomes were recorded.

Results

A total of 23 studies published in 2013-2024 were included in the analysis. In ten studies, the meniscus injury was associated with an anterior cruciate ligament (ACL) tear. In four studies, the effect of smoking on meniscal allograft transplantation (MAT) was investigated. The neutral effect of smoking on meniscus surgery was revealed in nine studies, and only one of them focused on isolated meniscus pathology and surgery. The negative effect of smoking on meniscus surgery was shown in ten papers, with four papers focused on isolated meniscus tears and six papers presenting data with concurrent ACL reconstructions.

Conclusions

This systematic review found that the results regarding the impact of smoking on meniscus repair outcomes were conflicting. Nevertheless, MAT and meniscus repair performed in the presence of concurrent ligamentous injury, both being demanding surgical procedures, require reduction of factors that may contribute to failure. Therefore, cessation of smoking in patients undergoing these procedures is highly advised.

The Meniscus: Basic Science and Therapeutic Approaches

The proper function and longevity of the knee joint are ensured by the knee menisci. Their susceptibility to damage and injury is one of the main risk factors for rapid cartilage loss and the development of osteoarthritis. The vascularization pattern and nutritional status of a torn meniscus determine its potential for healing and the success of meniscus surgery. Blood supply is a crucial factor in assessing healing potential. Knee cartilage volume loss and its modification often result from meniscal damage or excision, leading to osteoarthritis. Modern methods for preserving meniscal tissue are currently the treatment of choice. Magnetic resonance imaging (MRI) is the gold standard for assessing meniscus lesions. It provides a comprehensive evaluation of tear stability and progression risk. Additionally, it offers high sensitivity and specificity. Arthrography combined with computed tomography (CT) can be used for patients who are unable to undergo MRI. Other methods, such as X-ray and ultrasound, are not useful for the typical diagnosis of meniscal lesions. Minimally invasive surgery has become the gold standard for both treatment and diagnosis. Modern techniques, such as all-inside compression sutures and other suturing techniques, are also considered. In contrast, in the past, open total meniscectomy was routinely performed as the gold standard, based on the mistaken belief that the menisci were functionless. Currently, new treatment methods for meniscal lesions are being explored, including mesenchymal stem cells, synthetic implants, and platelet-rich plasma (PRP). The crucial role of the menisci in knee biomechanics drives the development of modern solutions focused on preserving meniscal tissue.

Early Meniscal Repair Leads to Higher Success Rates Than Delayed Meniscal Repair: A Systematic Review and Meta-analysis

BACKGROUND

There has been an increased interest in meniscus preservation over the last decade. Several risk factors for the failure of meniscal repair have been identified. However, the timing of meniscal repair has not been extensively assessed in the literature, and there is currently no high-quality evidence on the optimal timing of performing meniscal repair after an injury with regard to outcomes.

PURPOSE

To assess the role of the timing of meniscal repair on outcomes in the literature.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

The databases of PubMed, Embase, and the Cochrane Library were searched in October 2023 for studies comparing the outcomes of early versus delayed meniscal repair. Studies were eligible for inclusion if they reported outcomes within and after a time threshold (eg, within and after 3 weeks). Random-effects models were used.

RESULTS

A total of 35 studies with 3556 patients and 3767 menisci were included (mean age, 27.5 years; 66% male; mean follow-up, 4.5 years). Most studies were level 3 or 4 evidence, and the overall quality was low. The failure rates of meniscal repair were 11.3% versus 24.1% within versus after 2 weeks, respectively (7 studies, 511 patients; odds ratio [OR], 0.50 [95% CI, 0.22-1.16]; P = .11); 7.2% versus 15.3% within versus after 3 weeks, respectively (5 studies, 556 patients; OR, 0.28 [95% CI, 0.10-0.79]; P = .02); 15.7% versus 21.3% within versus after 6 weeks, respectively (7 studies, 746 patients; OR, 0.63 [95% CI, 0.33-1.18]; P = .15); and 10.2% versus 18.7% within versus after 8 weeks, respectively (7 studies, 652 patients; OR, 0.47 [95% CI, 0.26-0.87]; P = .02); these were significant for 3 and 8 weeks. No differences were seen for within versus after 3 months (7 studies, 1305 patients; 22.4% vs 18.5%, respectively; OR, 1.04 [95% CI, 0.47-2.33]; P = .92).

CONCLUSION

The timing of meniscal surgery was correlated with the likelihood of success, and meniscal repair should preferably be performed within 8 weeks of the injury, with the earliest benefit at 3 weeks. Clinicians should take this into consideration when recommending operative treatment or initial nonoperative treatment.

Medial and Lateral Meniscus Root Tear: Etiopathogenesis and Morphological Pattern in Indian Population

Objective

This study aims to enhance our understanding of the morphological pattern, causes and pathogenesis of meniscal root injuries in the Indian population.

Materials and Methods

Sixty-four patients with meniscus root tears were included in the study. The patients were categorized into two groups based on the location of the meniscus tear: Group 1 (n = 41) comprised patients with lateral meniscus root injury (LMRI), and Group 2 (n = 23) included patients with medial meniscus root injury (MMRI). Demographic and patient-specific data, such as age, gender, BMI, history of injury, and injury type, were recorded. All patients underwent surgical treatment, and intraoperative findings (chondral damage grade, type of root injury, associated ligamentous injuries) were documented. Meniscus root tears are further classified into 5 categories depending upon their morphological types. A minimum 12-month follow-up assessed functional outcomes using the Lysholm and IKDC knee scores.

Results

The mean age for MMRI and LMRI was 50.3 years and 29.4 years, respectively. In the MMRI group, 48% (11/23) were female compared to only 15% (6/41) in the LMRI group. The mean BMI in the MMRI and LMRI groups was 30.1 and 25.4, respectively. Nine patients in MMRI and 4 patients in LMRI group exhibited grade 3 or higher chondral damage. Type 2 meniscus root tear was most common type in both the groups (51% in MMRI vs. 74% in LMRI). Both LMRI and MMRI groups demonstrated significant improvement in functional outcomes.

Conclusions

Medial meniscus root injuries predominantly occur in the elderly without a significant history of trauma, often associated with a high grade of medial femoral chondral damage, suggesting a degenerative etiology. In contrast, lateral meniscus root injuries tend to occur in younger patients with a notable history of knee injury, indicative of a traumatic etiology for LMRI.

Greater Rotational Knee Laxity Observed at Second-Look Arthroscopy in Patients With Failed Meniscal Repair Performed at the Time of Anterior Cruciate Ligament Reconstruction

PURPOSE

To evaluate the healing of meniscal repair performed concomitantly with anterior cruciate ligament reconstruction (ACLR) using second-look arthroscopy, as well as the relationship between meniscal healing and knee laxity using quantitative evaluation under anesthesia.

METHODS

This retrospective study included patients who underwent primary double-bundle ACLR with meniscal repair between June 2016 and June 2021, with a 2-year minimum follow-up. Meniscal healing was evaluated by second-look arthroscopy at least 1 year postoperatively, and knee laxity was measured under general anesthesia preoperatively, intraoperatively, and at second-look arthroscopy.

RESULTS

Of 562 knees treated with ACLR, 113 knees, with 137 meniscal repairs, were analyzed. Second-look arthroscopy classified 114 menisci (83.2%) as healed and 23 (16.8%) as failed. The side-to-side difference in anterior tibial translation (ATT) and the side-to-side ratios of tibial acceleration and external rotational angular velocity (ERAV) improved intraoperatively in both groups (ATT, 6.0 to -1.0 mm [P < .001] and 6.0 to -1.0 mm [P < .001]; acceleration, 5.1 to 1.2 and 4.9 to 1.1 [P < .001]; ERAV, 3.6 to 1.3 and 3.6 to 1.6 [P < .001]). There were no significant differences in ATT and patient-reported outcome measures, including the Lysholm score and Knee Injury and Osteoarthritis Outcome Score (KOOS), between the groups. The proportion of patients achieving the minimal clinically important difference for the Lysholm score and KOOS did not differ significantly between the groups. However, at 1 year postoperatively, acceleration and ERAV were higher in the failed group than in the healed group (P < .001).

CONCLUSIONS

Patients with failure of meniscal repair performed concomitantly with ACLR showed significantly greater rotational knee laxity at the time of second-look arthroscopy. These patients exhibited significantly higher preoperative and postoperative pivot-shift grades than those who did not experience failure of meniscal repair. There were no significant differences in ATT and patient-reported outcome measures between the groups.

LEVEL OF EVIDENCE

Level Ⅲ, retrospective comparative study.

Efficacy of platelet-rich plasma in meniscal repair surgery: a systematic review of randomized controlled trials

PURPOSE

This study's primary objective was to evaluate the effectiveness of platelet-rich plasma (PRP) administration for meniscal injuries treated with meniscal repair procedures (sutures), using radiologic measures and clinical scales. The secondary objective was to identify potential bias-inducing elements in the analyzed studies.

METHODS

In December 2023, a systematic search was conducted in PubMed, Cochrane, Embase, and Scopus for randomized controlled trials. This review compares PRP with placebo. Three studies were finally selected. The risk of bias was assessed using Cochrane's Risk of Bias Tool 2. Radiologic evaluation of meniscal healing was measured with magnetic resonance imaging (MRI) and arthroscopic studies, while clinical evaluation was performed using four scales [Knee Injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS), International Knee Documentation Committee Subjective Knee Form (IKDC), and Western Ontario and McMaster Universities Index (WOMAC)] and by recording the incidence of complications.

RESULTS

The three selected studies included 139 patients; of these, 76 (54.7%) were randomly assigned to the intervention group (PRP injection) and 63 (45.3%) to the control group (placebo). The mean age of the intervention group was 37.4 ± 7.5 years, while the mean age of the control group was 36.5 ± 9.2 years. There were 41 female patients (29.5%). The median follow-up duration was 27.58 ± 17.3 months. MRI evaluation did not show a significant improvement in the PRP group in any of the studies (p-value = 0.41-0.54). However, when assessed by the cumulative evaluation of MRI and arthroscopy, the cumulative failure rate was significantly better in the PRP group (p-value = 0.04-0.048). One study that evaluated isolated arthroscopy also showed significant improvement in the PRP group (p = 0.003). Regarding the VAS scale, no study demonstrated a significant difference, except for one study that showed significant improvement after 6 months and in the difference between the 3rd and 6th months. The KOOS scale yielded conflicting results; one study showed no significant difference, while the other two indicated significant improvement. The IKDC and WOMAC scales were evaluated in two studies, showing opposite results. All included studies reported no complications, and one study indicated no increased risk in the treatment group.

CONCLUSIONS

The results of this review indicate the necessity for further studies to make a definitive statement about the effectiveness of PRP administration in meniscal repair processes. Level of evidence Systematic review and meta-analysis of articles of level 1.

Diagnosis and Treatment Strategies of Meniscus Root Tears: A Scoping Review

Background

Meniscus root tears comprise 10% to 21% of all meniscal tears. These tears alter knee biomechanics, elevating contact pressure, akin to a meniscectomy. Consequently, they are linked to advanced joint degeneration and cartilage damage in the affected compartment.

Purpose

To systematically evaluate and relate the current literature describing the diagnosis and treatment strategies for meniscus root tears.

Study Design

Scoping review; Level of evidence, 4.

Methods

This review was conducted following the guidelines of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) extension for scoping reviews. Inclusion criteria encompassed English-language clinical and preclinical research, technical notes, and narrative reviews on meniscus root tears. Exclusion criteria were studies on patellar tendon rupture, studies on medial patellofemoral ligament rupture with additional knee joint ligament injuries, studies of patients <16 years old, and studies involving open fractures. The data were summarized using a descriptive analysis and a thematic analysis.

Results

After 1425 articles were identified, 461 studies were included; 17% (n = 78) were case reports or case series, 15% (n = 71) were technical notes, 9% (n = 41) addressed aspects of diagnosis, 7% (n = 32 ) were narrative reviews, and 5% (n = 21) were systematic reviews or meta-analyses. Studies presenting original data comprised 57% (n = 262) of all included studies, and 97% of the studies were of evidence levels 3 to 5. Contributions were mainly from the United States (n = 123; 27%), Republic of Korea (n = 102; 22%), and Japan (n = 99; 21%). Many studies (n = 216; 47%) focused on the treatment and outcomes of meniscus root tears. A significant chronological surge in the quantity of studies addressing the diagnosis and treatment of meniscus root tears was evident, particularly over the past 3 years. Consensus was found regarding the definition of meniscus root tears, the advantages of early repair, and postoperative rehabilitation protocols. The variations in surgical techniques and operative strategies created the greatest amount of contention, along with clinical assessment and imaging modalities.

Conclusion

High-level evidence studies for diagnosing and managing meniscus root tears were scarce. A consensus has yet to be reached regarding the role of concomitant osteotomy, comparison of repair techniques, the use of a centralization stitch, patient factors affecting outcomes, and long-term outcomes of nonoperative management.

All-Inside and Inside-Out Repair Techniques for Bucket-Handle Meniscus Tears Both Result in Improved Patient Outcomes and a Broad Range of Failure Rates: A Systematic Review

PURPOSE

To compare patient-reported outcomes, failure rates, risk factors for failure, and complications in patients with bucket-handle meniscus tears (BHMTs) undergoing repair with inside-out (IO) versus all-inside (AI) techniques.

METHODS

A literature search was performed using the PubMed, Embase, and Scopus databases from database inception to August 2023 according to the 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The inclusion criteria consisted of Level I to IV clinical studies published in the past 10 years with greater than 2 years of follow-up that evaluated patient-reported outcome scores and/or the incidence of failure after IO or AI repairs for BHMTs. Clinical studies not reporting outcomes or failure rates, older studies using outdated implants, animal studies, reviews, letters to the editor, case reports, cadaveric studies, and articles not written in the English language or with English-language translation were excluded. Study quality was assessed using the Methodological Index for Non-randomized Studies (MINORS) criteria. Outcomes were reported as ranges and qualitatively compared.

RESULTS

A total of 16 studies published from 2013 to 2023, consisting of 1,062 patients with BHMTs, were identified. Thirteen studies (14 cohorts, 649 patients) reported on AI repair (mean age range, 23.7-32 years) and 7 studies (7 cohorts, 413 patients) reported on IO repair (mean age range, 16.7-34.6 years). Both groups had improved postoperative Lysholm and Tegner scores. Decreased range of motion was the most commonly reported complication in the AI group (range, 2.6%-4%), whereas adhesions for arthrofibrosis were the most commonly reported complication in the IO group (n = 12; range, 6%-7.9%). The overall reported failure rate ranged from 6.9% to 20.5% within the AI group and from 0% to 20% within the IO group.

CONCLUSIONS

AI and IO repair techniques for BHMTs both result in improved Lysholm and Tegner scores. However, broad ranges of failure are reported in the literature, with overall failure rates ranging from 6.9% to 20.5% after AI repair and from 0% to 20% after IO repair. Younger age and isolated medial BHMT repair are the most frequently reported risk factors for the AI technique, whereas postoperative stiffness is the most frequently reported complication after both repair techniques.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

Repair of bucket handle meniscus tears improves patient outcomes versus partial meniscectomy at the time of ACL reconstruction

Purpose

The aim of this study was to examine demographic and surgical factors that influence patient-reported knee function in patients who undergo anterior crucial ligament reconstruction (ACLR) with concurrent bucket-handle meniscal tear (BHMT) procedures. We hypothesized that repair of BHMT in the setting of concomitant ACLR and shorter time from injury to surgery would lead to improved patient-reported outcomes.

Methods

Forty-one patients (mean age: 28.0 ± 9.8 years, 72% male) with BHMT at the time of ACLR completed the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) via online survey at an average of 15.2 months postop. Patient demographics and surgical characteristics, including time from injury to surgery, were compared between repair (n = 22) and meniscectomy (n = 19) groups using one-way analysis of variances; distributions of sex, graft source, BHMT compartment and zone were compared between groups using χ 2 tests. The association between IKDC-SKF score, demographics and surgical characteristics was evaluated using multivariable linear regression. A priori alpha level was p < 0.05.

Results

Meniscal repair and meniscectomy groups differed based on graft source and BHMT zone but not IKDC-SKF score (p = 0.085). Patients undergoing ACLR with autograft (p = 0.003) and with red-red zone BHMT (p < 0.001) more often underwent meniscal repair. The regression model demonstrated longer time from injury to surgery (p = 0.049), red-red tear zone (p = 0.04) and meniscectomy (p = 0.008); these were predictive of poorer IKDC-SKF scores.

Conclusion

BHMT repair was more likely performed in ACL autograft and on red-red zone tears. Longer time from injury to surgery is an indicator of poorer IKDC-SKF score, as this may increase the risk of concomitant pathologies. White-white zone BHMTs are associated with better IKDC-SKF scores than red-red zone BHMTs, which may be due to the smaller volume of tissue removed during meniscectomy of white-white zone tears and the avoidance of iatrogenic complications of meniscal repair.

Level of Evidence

Level III, therapeutic study.

More Is Not Merrier: Increasing Numbers of All-Inside Implants Do Not Correlate with Higher Odds of Revision Surgery

The purpose of this study was to evaluate the relationship between the number of all-inside meniscal repair implants placed and the risk of repair failure. We hypothesized that the use of higher numbers of all-inside meniscus repair implants would be associated with increased failure risk. A retrospective chart review identified 351 patients who underwent all-inside meniscus repair between 2006 and 2013 by a sports medicine fellowship-trained orthopaedic surgeon at a single institution. Patient demographics (age, body mass index [BMI], sex) and surgical data (number of implants used, concomitant anterior cruciate ligament reconstruction [cACLR], and tear type/size/location) were recorded. Patients who received repairs in both menisci or who had follow-up < 1-year postoperatively were excluded. Repair failure was identified through chart review or patient interviews defined as a revision surgery on the index knee such as partial meniscectomy, total knee arthroplasty, meniscus transplant, or repeat repair. Logistic regression modeling was utilized to evaluate the relationship between the number of implants used and repair failure. A total of 227 all-inside meniscus repairs were included with a mean follow-up of 5.0 ± 3.0 years following surgery. Repair failure was noted in 68 knees (30.3%)-in 28.1% of knees with fewer than four implants and in 35.8% of knees with four or more implants (p = 0.31). No significant increase in failure was observed with increasing number of all-inside medial (odds ratio [OR]: 1.15; 95% confidence interval [CI]: 0.79-1.7; p = 0.46) or lateral (OR: 0.86; 95% CI: 0.47-1.57; p = 0.63) implants after controlling for patient age, BMI, cACLR, tear type, or size. Tears of the lateral meniscus located in the red-white and white-white zones had lower odds of failure (OR: 0.14; 95% CI: 0.02-0.88; p = 0.036) than tears within the red-red zone, and patients with cACLR had lower odds of repair failure (OR: 0.40; 95% CI: 0.18-0.86, p = 0.024) than those without. The number of all-inside implants placed during meniscus tear repair did not affect the likelihood of repair failure leading to reoperation after controlling for BMI, age, tear type, size, location, and cACLR. LEVEL OF EVIDENCE:  III.

Degenerative Meniscus Tears Treated Nonoperatively With Platelet-Rich Plasma Yield Variable Clinical and Imaging Outcomes: A Systematic Review

Purpose

To perform a systematic review on clinical and radiologic outcomes for meniscus tears treated nonoperatively with platelet-rich plasma (PRP).

Methods

A literature search was performed according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using keywords and Boolean operators in SCOPUS, PubMed, Medline, and the Cochrane Central Register for Controlled Trials in April 2023. Inclusion criteria were limited to Level I to IV human studies reporting on outcomes of meniscus tears treated nonoperatively with PRP.

Results

A total of 6 studies, consisting of 184 patients, were identified. There was 1 Level I study and 5 Level IV studies. Mean patient age was 47.8 ± 7.9 years, with 62% (n = 114/184) being female. The medial meniscus was treated in 95.7% (n = 157/164) of patients. Mean follow-up ranged from 75.9 days to 31.9 months. Meniscus tears were generally described as chronic, degenerative, or intrasubstance. In 4 studies, magnetic resonance imaging revealed variable improvement in meniscus grade with complete healing in 0% to 44% of patients and partial healing in 0% to 40% of patients. Four of 5 studies reported significant statistical improvement in pain from baseline to final follow-up. Studies reporting on clinical outcomes showed significant improvements Lysholm score (2 studies), Knee injury and Osteoarthritis Outcome Score total score (2 studies), and Tegner score (1 study). Successful return to sport occurred in 60% to 100% of patients. Two studies reported that most patients were either very satisfied or satisfied following treatment.

Conclusions

The use of PRP injections for the treatment of meniscus tears led to variable results based on postoperative magnetic resonance evaluation and improvements in clinical outcomes, although the clinical significance remains unclear. The heterogeneity of PRP protocols, short-term follow-up, and lack of comparative studies limit findings.

Level of Evidence

Level IV, systematic review of Level I to IV studies.

Meniscal Repair Outcome in 3829 Patients With a Minimum Follow-up From 2 Years Up to 5 Years: A Meta-analysis on the Overall Failure Rate and Factors Influencing Failure

BACKGROUND

The importance of meniscal repair is widely accepted because of the association of loss of meniscal tissue with the development of early-onset knee arthritis. Many factors influencing the results of meniscal repair have been reported, but results remain controversial.

PURPOSE

This meta-analysis determines the pooled meniscal repair failure rate of studies with a minimum follow-up of 2 years up to 5 years, with a mean follow-up of 43 months. Moreover, selected failure-influencing factors are analyzed.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

PubMed and Scopus were searched for studies published between January 2000 and November 2021 reporting on meniscal repair outcome with a minimum follow-up of 24 months. The overall pooled failure rate and pooled failure rates for possible predictors were calculated. Random-effect models were used to pool failure rates, and effect estimates in the form of odds ratios with 95% CIs were established.

RESULTS

The initial literature search identified 6519 studies. A total of 51 studies met the inclusion criteria. In total, 3931 menisci were included with an overall failure rate of 14.8%. Subgroup analysis revealed a significantly lower failure rate for meniscal repair with concomitant anterior cruciate ligament (ACL) reconstruction compared with knees without any reported injury to the ACL (8.5% vs 14%; P = .043). The pooled failure rate for lateral meniscal repair was significantly lower than that for medial meniscal repair (6.1% vs 10.8%; P = .031). Pooled failure rates of all-inside and inside-out repair were not significantly different (11.9% vs 10.6%; P > .05).

CONCLUSION

This meta-analysis on close to 4000 patients demonstrates an overall meniscal repair failure rate of 14.8% at a minimum follow-up from 2 years up to 5 years. Meniscal repair remains a procedure with a high failure rate, especially within the first 2 postoperative years. This review and meta-analysis also identified clinically relevant factors associated with favorable outcomes such as concomitant ACL reconstruction or repair of the lateral meniscus. All-inside meniscal repair with the latest-generation devices yields failure rates of <10%. The failure mechanism and the time of failure is poorly documented; further studies are needed for a better understanding of the retear mechanism.

Prevalence and Predictors of Concomitant Meniscal Surgery During Pediatric and Adolescent ACL Reconstruction: Analysis of 4729 Patients Over 20 Years at a Tertiary-Care Regional Children's Hospital

Background

The rate of concomitant meniscal procedures performed in conjunction with anterior cruciate ligament (ACL) reconstruction is increasing. Few studies have examined these procedures in high-risk pediatric cohorts.

Hypotheses

That (1) the rates of meniscal repair compared with meniscectomy would increase throughout the study period and (2) patient-related factors would be able to predict the type of meniscal operation, which would differ according to age.

Study Design

Cohort study (prevalence); Level of evidence, 2.

Methods

Natural language processing was used to extract clinical variables from notes of patients who underwent ACL reconstruction between 2000 and 2020 at a single institution. Patients were stratified to pediatric (5-13 years) and adolescent (14-19 years) cohorts. Linear regression was used to evaluate changes in the prevalence of concomitant meniscal surgery during the study period. Logistic regression was used to determine predictors of the need for and type of meniscal procedure.

Results

Of 4729 patients (mean age, 16 ± 2 years; 54.7% female) identified, 2458 patients (52%) underwent concomitant meniscal procedures (55% repair rate). The prevalence of lateral meniscal (LM) procedures increased in both pediatric and adolescent cohorts, whereas the prevalence of medial meniscal (MM) repair increased in the adolescent cohort (P = .02). In the adolescent cohort, older age was predictive of concomitant medial meniscectomy (P = .031). In the pediatric cohort, female sex was predictive of concomitant MM surgery and of undergoing lateral meniscectomy versus repair (P≤ .029). Female sex was associated with decreased odds of concomitant LM surgery in both cohorts (P≤ .018). Revision ACLR was predictive of concomitant MM surgery and of meniscectomy (medial and lateral) in the adolescent cohort (P < .001). Higher body mass index was associated with increased odds of undergoing medial meniscectomy versus repair in the pediatric cohort (P = .03).

Conclusion

More than half of the young patients who underwent ACLR had meniscal pathology warranting surgical intervention. The prevalence of MM repair compared with meniscectomy in adolescents increased throughout the study period. Patients who underwent revision ACLR were more likely to undergo concomitant meniscal surgeries, which were more often meniscectomy. Female sex had mixed effects in both the pediatric and adolescent cohorts.

Meniscectomy is associated with a higher rate of osteoarthritis compared to meniscal repair following acute tears: a meta-analysis

PURPOSE

Meniscal tears are common and may impair knee function and biomechanics. This meta-analysis compared meniscal repair versus resection in patients with symptomatic meniscal tears in terms of patient-reported outcomes measures (PROMs), joint width, surgical failure, and rate of progression to osteoarthritis (OA) at conventional radiography.

METHODS

This study was conducted according to the 2020 PRISMA statement. In August 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. Two reviewers independently performed the analysis and a methodological quality assessment of the included studies. All the clinical investigations which compared repair versus resection of meniscal tears were accessed.

RESULTS

Data from 20 studies (31,783 patients) were collected. The mean BMI was 28.28 ± 3.2 kg/m2, and the mean age was 37.6 ± 14.0 years. The mean time elapsed from injury to surgery was 12.1 ± 10.2 months and the mean medial joint width was 4.9 ± 0.8 mm. Between studies comparability at baseline was found in age, women, BMI, time from injury to surgery and length of the follow-up, PROMs, medial joint width, and stage of OA. The resection group demonstrated a greater Lysholm score (P = 0.02). No difference was found in the International Knee Documentation Committee (P = 0.2). Nine studies reported data on the rate of failures at a mean of 63.00 ± 24.7 months. No difference was found between the two groups in terms of persistent meniscal symptoms (P = 0.8). Six studies reported data on the rate of progression to total knee arthroplasty at a mean of 48.0 ± 14.7 months follow-up. The repair group evidenced a lower rate of progression to knee arthroplasty (P = 0.0001). Six studies reported data on the rate of advanced knee OA at a mean of 48.0 ± 14.7 months of follow-up. The repair group evidenced a lower rate of advanced knee OA (P = 0.0001). No difference was found in the mean joint space width (P = 0.09).

CONCLUSION

Meniscal repair is associated with a lower progression to knee osteoarthritis at approximately six years of follow-up compared to partial meniscectomy. No difference in PROMs, medial joint width, and failures were evidenced.

LEVEL OF EVIDENCE

Level III, meta-analysis.

Arthroscopic Meniscectomy vs Meniscal Repair: Comparison of Clinical Outcomes

Background Meniscal tears are the most common injury of the knee. Surgical treatment has fallen into contention recently and includes arthroscopic meniscectomy and meniscal repair. The primary aim of this study was to quantitatively evaluate patients with isolated meniscal tears and compare their outcomes with patients who have undergone arthroscopic meniscus surgery. The secondary aim of this study was to compare the clinical outcomes of patients who have undergone arthroscopic meniscectomy with patients who have undergone arthroscopic meniscal repair. Methods This comparative clinical study screened 334 patients to identify subjects who underwent arthroscopic knee surgery for isolated meniscal tears and compare them to patients with symptomatic isolated meniscal tears awaiting surgery using validated patient-reported outcome measures. These included the Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee Subjective Knee Form, Lysholm score, Tegner score, EuroQol-5 Dimension, and the 12-Item Short Form Health Survey. Results A total of 117 patients (Meniscal Tear group (n=36), Meniscectomy group (n=64), and Meniscal Repair group (n=17)) were included in the final data analysis. Both the Meniscectomy group and the Meniscal Repair group (mean 55-month follow-up) showed significantly better clinical outcomes than patients in the Meniscal Tear group (p<0.05). Overall, the Meniscal Repair group demonstrated superior clinical outcomes when compared to the Meniscectomy group (p<0.05). Conclusion Arthroscopic knee surgery showed significant clinical benefit at medium-term follow-up in treating patients with isolated meniscal tears. When feasible, meniscal repair should be performed preferentially over meniscectomy.

Three-Dimensional Imaging and Quantitative Analysis of Blood Vessel Distribution in The Meniscus of Transgenic Mouse after Tissue Clearing

OBJECTIVE

Blood supply to the meniscus determines its recovery and is a reference for treatment planning. This study aimed to apply tissue clearing and three-dimensional (3D) imaging in exploring the quantitative distribution of blood vessels in the mouse meniscus.

MATERIALS AND METHODS

In this experimental study, tissue clearing was performed to treat the bilateral knee joints of transgenic mice with fluorescent vascular endothelial cells. Images were acquired using a light sheet microscope and the vascular endothelial cells in the meniscus was analysed using 3D imaging. Quantitative methods were employed to further analyse the blood vessel distribution in the mouse meniscus.

RESULTS

The traditional three-equal-width division of the meniscus is as follows: the outer one-third is the red-red zone (RR), the inner one-third is the white-white zone (WW), and the transition area is the red-white zone (RW). The division revealed significant signal differences between the RW and WW (P<0.05) zones, but no significant differences between the RR and RW zones, which indicated that the division might not accurately reflect the blood supply of the meniscus. According to the modified division (4:2:1) in which significant differences were ensured between the adjacent zones, we observed that the width ratio of each zone was 38 ± 1% (RR), 24 ± 1% (RW), and 38 ± 2% (WW). Furthermore, the blood supply to each region was verified. The anterior region had the most abundant blood supply. The fluorescence count in the anterior region was significantly higher than in the central and posterior regions (P<0.05). The blood supply of the medial meniscus was superior to the lateral meniscus (P<0.05).

CONCLUSION

Analysis of the blood supply to the mouse meniscus under tissue clearing and 3D imaging reflect quantitative blood vessel distribution, which would facilitate future evaluations of the human meniscus and provide more anatomical references for clinicians.

Knee MRI: Meniscus Roots, Ramps, Repairs, and Repercussions

Menisci play an essential role in maintaining normal pain-free function of the knee. While there are decades of MRI literature on the tears involving the meniscus body and horns, there is now a surge in knowledge regarding injuries at the meniscus roots and periphery. The authors briefly highlight new insights into meniscus anatomy and then summarize recent developments in the understanding of meniscus injuries that matter, emphasizing meniscus injuries at the root and peripheral (eg, ramp) regions that may be missed easily at MRI and arthroscopy. Root and ramp tears are important to diagnose because they may be amenable to repair. However, if these tears are left untreated, ongoing pain and accelerated cartilage degeneration may ensue. The posterior roots of the medial and lateral menisci are most commonly affected by injury, and each of these injuries is associated with distinctive clinical profiles, MRI findings, and tear patterns. Specific diagnostic pitfalls can make the roots challenging to evaluate, including MRI artifacts and anatomic variations. As with root tears, MRI interpretation and orthopedic treatment have important differences for injuries at the medial versus lateral meniscus (LM) periphery (located at or near the meniscocapsular junction). Medially, ramp lesions typically occur in the setting of an anterior cruciate ligament rupture and are generally classified into five patterns. Laterally, the meniscocapsular junction may be injured in association with tibial plateau fractures, but disruption of the popliteomeniscal fascicles may also result in a hypermobile LM. Updated knowledge of the meniscus root and ramp tears is crucial in optimizing diagnostic imaging before repair and understanding the clinical repercussions. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available in the Online Learning Center.

Meniscal Extrusion: Diagnosis, Etiology, and Treatment Options

PURPOSE OF REVIEW

The concept of meniscal extrusion has recently been recognized as a hallmark of meniscus dysfunction. This review examines contemporary literature regarding the pathophysiology, classification, diagnosis, treatment, and future directions for investigation regarding meniscus extrusion.

RECENT FINDINGS

Meniscus extrusion, defined as >3 mm of radial displacement of the meniscus, leads to altered knee biomechanics and accelerated knee joint degeneration. Meniscus extrusion has been associated with degenerative joint disease, posterior root and radial meniscal tears, and acute trauma. Meniscus centralization and meniscotibial ligament repair have been proposed as techniques to address meniscal extrusion with promising biomechanical, animal model, and early clinical reports. Further studies on the epidemiology of meniscus extrusion and associated long-term nonoperative outcomes will help to elucidate its role in meniscus dysfunction and resultant arthritic development. Understanding and appreciation for the anatomic attachments of the meniscus will help to inform future repair techniques. Long-term reporting on the clinical outcomes of meniscus centralization techniques will yield insights into the clinical significance of meniscus extrusion correction.

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

Over the years, several studies demonstrated the crucial role of knee menisci in joint biomechanics. As a result, save the meniscus has become the new imperative nowadays, and more and more studies addressed this topic. The huge amount of data on this topic may create confusion in those who want to approach this surgery. The aim of this review is to provide a practical guide for treatment of meniscus tears, including an overview of technical aspects, outcomes in the literature and personal tips. Taking inspiration from a famous movie directed by Sergio Leone in 1966, the authors classified meniscus tears in three categories: The good, the bad and the ugly lesions. The inclusion in each group was determined by the lesion pattern, its biomechanical effects on knee joint, the technical challenge, and prognosis. This classification is not intended to substitute the currently proposed classifications on meniscus tears but aims at offering a reader-friendly narrative review of an otherwise difficult topic. Furthermore, the authors provide a concise premise to deal with some aspects of menisci phylogeny, anatomy and biomechanics.

The Interplay of Biomechanical and Biological Changes Following Meniscus Injury

PURPOSE OF REVIEW

Meniscus injury often leads to joint degeneration and post-traumatic osteoarthritis (PTOA) development. Therefore, the purpose of this review is to outline the current understanding of biomechanical and biological repercussions following meniscus injury and how these changes impact meniscus repair and PTOA development. Moreover, we identify key gaps in knowledge that must be further investigated to improve meniscus healing and prevent PTOA.

RECENT FINDINGS

Following meniscus injury, both biomechanical and biological alterations frequently occur in multiple tissues in the joint. Biomechanically, meniscus tears compromise the ability of the meniscus to transfer load in the joint, making the cartilage more vulnerable to increased strain. Biologically, the post-injury environment is often characterized by an increase in pro-inflammatory cytokines, catabolic enzymes, and immune cells. These multi-faceted changes have a significant interplay and result in an environment that opposes tissue repair and contributes to PTOA development. Additionally, degenerative changes associated with OA may cause a feedback cycle, negatively impacting the healing capacity of the meniscus. Strides have been made towards understanding post-injury biological and biomechanical changes in the joint, their interplay, and how they affect healing and PTOA development. However, in order to improve clinical treatments to promote meniscus healing and prevent PTOA development, there is an urgent need to understand the physiologic changes in the joint following injury. In particular, work is needed on the in vivo characterization of the temporal biomechanical and biological changes that occur in patients following meniscus injury and how these changes contribute to PTOA development.

Current and Future Applications of Fluorescence Guidance in Orthopaedic Surgery

Fluorescence-guided surgery (FGS) is an evolving field that seeks to identify important anatomic structures or physiologic phenomena with helpful relevance to the execution of surgical procedures. Fluorescence labeling occurs generally via the administration of fluorescent reporters that may be molecularly targeted, enzyme-activated, or untargeted, vascular probes. Fluorescence guidance has substantially changed care strategies in numerous surgical fields; however, investigation and adoption in orthopaedic surgery have lagged. FGS shows the potential for improving patient care in orthopaedics via several applications including disease diagnosis, perfusion-based tissue healing capacity assessment, infection/tumor eradication, and anatomic structure identification. This review highlights current and future applications of fluorescence guidance in orthopaedics and identifies key challenges to translation and potential solutions.

Smoking Has No Influence on Outcomes after Repair of the Medial Meniscus in the Hypo and Avascular Zones-A Pilot Study

Complete loss of the meniscus inevitably leads to knee joint degeneration. Smoking is an important factor predicting poor outcome in orthopedics; however, data about its role in meniscus surgery are inconclusive. Smoking could be an important negative factor in isolated meniscus repair. The aim of this paper was to determine the influence of smoking on functional outcomes after isolated all-inside medial meniscus repair. This study included 50 consecutive patients with isolated, traumatic tear of the medial meniscus who underwent knee joint arthroscopy between 2016 and 2019. All-inside arthroscopic repair of the medial meniscus was performed in each case. All patients followed a uniform, postoperative rehabilitation protocol for 8 weeks. The follow-up examination was based on the functional scores at 3 and 6 months postoperatively. According to smoking status there were 17 smokers and 33 non-smokers. The mean number of cigarettes smoked per day was 11, for a mean of 7.4 years, and the mean pack-years index value was 4.9. There was no correlation between smoking years, number of cigarettes smoked per day, pack-years index, and functional outcomes. The arthroscopic inspection of the knee joints revealed cartilage lesions (≤IIº) in eight subjects, suggesting the secondary pathology to the meniscus tear. In this study, we found no evidence of an association between smoking indices and functional outcomes after all-inside repair of chronic medial meniscus tear. The nature of the chronic meniscal tear could be smoking-resistant owing to the poor blood supply to the sites in which these specific lesions occur.

Mapping knowledge structure and research trends of knee osteoarthritis with meniscus in two decades: A bibliometric analysis

BACKGROUND

Knee osteoarthritis (KOA) is a chronic degenerative disease that is closely related to the meniscus. Currently, no bibliometric studies have jointly analyzed KOA and the meniscus. This study aimed to provide a comprehensive analysis of the knowledge structure of KOA and the meniscus across two decades and to identify the emerging research trends from a bibliometric perspective.

METHODS

All articles reporting KOA and the meniscus from 2001 to 2021 were obtained from the Web of Science Core Collection. R software, CiteSpace, VOS Viewer, and Microsoft Excel were used to analyze the publications including the authors, cited authors, journals, cited journals, country of research, institutions, and research focus. These data were used to generate visual knowledge maps of the outputs.

RESULTS

A total of 3,218 articles were retrieved. Guermazi was identified as the author who had contributed the most to the field and Osteoarthritis and Cartilage was identified as the most productive research journal. The United States is the global leader in the field and the center for international cooperation with less international collaboration occurring in Eastern Asia. Boston University was the most prolific institution. According to the data, "articular-cartilage," "meniscectomy," "follow-up," "anterior cruciate ligament," and "cartilage" were identified as research hotspots in the field. "Consequences," "prognostic-factors," and "receptor" were predicted as future hot topics of research.

CONCLUSIONS

This study is the first comprehensive bibliometric study to jointly analyze KOA and the meniscus. Our data enable a better understanding of research trends and identify research hotspots and gaps in knowledge across the field. Our findings provide practical information for researchers to better understand the key research areas and identify the research frontiers and future hot topics.

Repair of a Horizontal Cleavage Tear of the Lateral Meniscus with Circumferential Compression Stitches and Marrow Venting Augmentation

Horizontal cleavage tears (HCTs) are challenging meniscal tear patterns, as they split the meniscus into inferior and superior leaflets, while also involving the central, less vascular portions of the meniscus. Circumferential compression sutures using an all-inside self-retrieving suture passing device like the Novostitch Pro (Smith & Nephew, Andover, MA) have demonstrated the ability to create stable repair constructs with uniform compression across both leaflets in the setting of HCTs. Additionally, biological augmentation of meniscal repairs using a marrow venting procedure (MVP) has demonstrated superior clinical outcomes relative to isolated meniscal repairs. Thus, the purpose of this technical note is to outline our procedure for implementing circumferential compression sutures and biologic augmentation using an MVP for repairing an HCT of the lateral meniscus.

Review of Meniscus Anatomy and Biomechanics

PURPOSE OF REVIEW

Anatomic repair of meniscal pathology is critical for restoring native joint biomechanics and kinematics for patients who suffer from meniscal tears. The purpose of this review was to summarize the pertinent anatomy, biomechanics, and kinematics of the meniscus to guide surgeons during meniscal repair procedures.

RECENT FINDINGS

Over the past decade, there has been a growing trend to save the meniscus whenever possible. The goal of repair should be to recreate native anatomy as close as possible to recapitulate normal mechanics. Studies describing the quantitative and qualitative relationship of the meniscus roots, ligaments, and attachments are key in guiding any meniscus repair. This review summarizes these relationships, with particular emphasis on meniscal roots and other key attachments to the meniscus. The composition, embryology, vascularization, biomechanics, in vivo kinetics, and in vivo kinematics of the meniscus are also discussed in this review. Meniscal tears can cause profound functional, biomechanical, and kinematic derangements within the knee joint leading to accelerated degeneration of the articular cartilage. A strong understanding of the quantitative and qualitative relationships of the meniscus and its attachments with key arthroscopic landmarks will allow a surgeon to anatomically repair meniscal pathology in order to restore native joint biomechanics.

Primary Fixation and Cyclic Performance of Single-Stitch All-Inside and Inside-Out Meniscal Devices for Repairing Vertical Longitudinal Meniscal Tears

BACKGROUND

Primary device fixation and the resistance against gap formation during repetitive loading influence the quality of meniscal repair. There are limited biomechanical data comparing primary tensioning and cyclic behavior of all-inside versus inside-out repair.

HYPOTHESIS

All-inside devices provide higher initial load on the meniscal repair than inside-out fixation, and stiffer constructs show higher resistance against gap formation during cyclic loading.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 60 longitudinal bucket-handle tears in human cadaveric menisci were created and repaired with a single stitch and randomly assigned to 4 all-inside groups (TrueSpan, FastFix 360, Stryker AIR, FiberStich) and 2 inside-out groups (suture repair [IO-S], suture tape [IO-ST]). Residual load after repair tensioning (50 N) and relief displacement were measured. Constructs underwent cyclic loading between 2 and 20 N over 500 cycles (0.75 Hz) with cyclic stiffness, gap formation, and final peak elongation measured. Ultimate load and stiffness were analyzed during pull to failure (3.15 mm/s).

RESULTS

All-inside repair demonstrated significantly higher primary fixation strength than inside-out repair. The significantly highest load (mean ± SD; 20.1 ± 0.9 N; P < .037) and relief displacement (-2.40 ± 0.32 mm; P < .03) were for the knotless soft anchoring FiberStich group. The lowest initial load (9.0 ± 1.5 N; P < .001) and relief displacement (-1.39 ± 0.26 mm; P < .045) were for the IO-S repair group. The final gap formation (500th cycle) of FiberStich (0.75 ± 0.37 mm; P < .02) was significantly smaller than others and that of the IO-S (1.47 ± 0.33 mm; P < .045) significantly larger. The construct stiffness of the FiberStich and IO-ST groups was significantly greater at the end of cyclic testing (16.7 ± 0.80 and 15.5 ± 1.42 N/mm; P < .042, respectively) and ultimate failure testing (23.4 ± 3.6 and 20.6 ± 2.3 N/mm; P < .005). The FastFix 360 (86.4 ± 4.8 N) and Stryker AIR (84.4 ± 4.6 N) groups failed at a significantly lower load than the IO-S group (P < .02) with loss of anchor support. The FiberStich (146.8 ± 23.4 N), TrueSpan (142.0 ± 17.8 N), and IO-ST (139.4 ± 7.3 N) groups failed at significantly higher loads (P < .02) due to suture tearing.

CONCLUSION

Overall, primary fixation strength of inside-out meniscal repair was significantly lower than all-inside repair in this cadaveric tissue model. Although absolute differences among groups were small, meniscal repairs with higher construct stiffness (IO-ST, FiberStich) demonstrated increased resistance against gap formation and failure load.

CLINICAL RELEVANCE

Knotless single-stitch all-inside meniscal repair with a soft anchor resulted in less gapping, but the overall clinical significance on healing rates remains unclear.

Treatment Trends in Meniscal Pathology in the Setting of Concomitant ACL Injuries in Pediatric and Young Adult Patients: An Insurance Database Study

BACKGROUND

Meniscal pathology is commonly encountered in the setting of anterior cruciate ligament (ACL) rupture and is increasingly common in the pediatric and adolescent population. Studies have shown that over half of individuals presenting with ACL rupture will have concurrent meniscal pathology.

PURPOSE

To define trends in the utilization of meniscal procedures (ie, meniscus repair vs partial meniscectomy) and short-term complications in pediatric and young adult patients with meniscal pathology in the setting of a concurrent ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The IBM MarketScan Commercial Database was utilized to identify ACL reconstruction procedures performed between 2006 and 2018 for individuals aged 5 to 30 years. Annual proportions of meniscectomy and meniscal repair were analyzed, and short-term complications were compared between pediatric/adolescent patients (aged 5-17 years) and young adults (aged 18-30 years).

RESULTS

An overall 40,736 records of individuals <18 years old with ACL tears were included. The pediatric/adolescent population had a significantly lower proportion of concomitant meniscal procedures (56.8%; 23,149/40,736) than the young adult population (59.7%; 33,764/56,515; P < .01). From 2006 to 2018, utilization of meniscal repair in the setting of ACL reconstruction steadily increased (20.1% to 35.1% [+15 percentage points], P < .01), while the proportion with meniscectomy decreased (34.4% to 21.3% [-13.1 percentage points], P < .01). There was no difference in rate of reoperation for repeat meniscal repair or meniscectomy in the pediatric/adolescent population for those undergoing meniscal repair versus meniscectomy within 180 days of primary surgery (1.7% [188/10,766] vs 1.5% [186/12,383]; P = .14).

CONCLUSION

From 2006 to 2018, the proportion of patients receiving ACL reconstruction with concomitant meniscal repair increased (20.1% to 35.1%) while the proportion with meniscectomy decreased (34.4% to 21.3%) in the pediatric/adolescent population. Meniscal repair was not associated with a higher 180-day rate of reoperation for repeat meniscal repair or meniscectomy than meniscectomy in the setting of ACL reconstruction.

Meniscal Extrusion: A Critical Analysis Review

➢

Pathologic meniscal extrusion can compromise meniscal function, leading to increased contact forces in the tibiofemoral compartment and the acceleration of osteoarthritic changes.

➢

Extrusion is typically defined as radial displacement of ≥3 mm outside the tibial border and is best diagnosed via magnetic resonance imaging, although ultrasonography has also demonstrated encouraging diagnostic utility.

➢

Surgical management of meniscal extrusion is based on the underlying etiology, the patient's symptom profile, the preexisting health of the articular surface, and the risk of future chondral injury and osteoarthritis.

Higher healing rate after meniscal repair with concomitant ACL reconstruction for tears located in vascular zone 1 compared to zone 2: a systematic review and meta-analysis

PURPOSE

The purpose of this study was to determine and compare the percentage of completely healed meniscal tears after arthroscopic repair combined with anterior cruciate ligament reconstruction (ACLR) for the different vascular zones of the meniscus.

METHODS

PubMed, Embase, Web of Science, Cochrane library and Emcare were searched on 19 May 2020 for articles reporting healing rates after arthroscopic meniscal repair with concomitant ACLR for the different meniscal vascular zones as assessed by second-look arthroscopy. Data on meniscal tears were extracted as located in zones 1, 2 or 3, according to the Cooper classification. Studies were graded in quality using a modified Newcastle-Ottawa Scale. Pooled analyses were performed utilizing a random-effects model. Meta-analyses were performed using R version 3.6.2 and SPSS statistical software version 25.0. The study was registered with PROSPERO (ID:CRD42020176175).

RESULTS

Ten observational cohort studies met the inclusion criteria, accounting for 758 meniscal tear repairs in total. The pooled overall proportion of healing was 78% (95% CI 72-84%). The mean weighted proportion of healing was 83% (95% CI 76-90%) for studies (n = 10) reporting zone 1 tears and 69% (95% CI 59-79%) for studies (n = 9) reporting zone 2 tears. No study reported healing rates for zone 3 tears. The pooled overall odds ratio was 2.5 (95% CI 1.00-6.02), indicating zone 1 tears as 2.5 times more likely to heal than zone 2 tears.

CONCLUSION

This study demonstrates that meniscal tears localized in vascular zone 1 were more likely to heal than those in zone 2.

LEVEL OF EVIDENCE

IV.

Meniscal Root Tears: A Decade of Research on their Relevant Anatomy, Biomechanics, Diagnosis, and Treatment

A foundational knowledge of the anatomy and biomechanics of meniscal root tears is warranted for proper repair of meniscal root tears and for preventing some of their commonly described iatrogenic causes. Meniscal root tears are defined as either a radial tear occurring within one cm of the root attachment site of the meniscus or a complete bony or soft tissue avulsion of the root attachment altogether. Meniscal root tears disrupt the protective biomechanical function of the native meniscus. Biomechanical analyses of the current techniques for meniscal root repair highlight the importance of restoring menisci to their correct anatomic orientation, thereby restoring their biomechanical function. A comprehensive understanding of the clinical and radiographic presentations of these injuries is critical to preventing their underdiagnosis. The poor long-term outcomes associated with conservative treatment measures, namely, ipsilateral compartment osteoarthritis, warrants the surgical repair of meniscal root tears whenever possible. While excellent patient-reported outcomes exist for the various surgical repair techniques, adherence to stringent post-operative rehabilitation protocols is critical for patients to avoid damaging the integrity of a repaired root. This review will focus on current concepts pertaining to the anatomy, biomechanics, diagnosis, treatment, and postoperative rehabilitation for meniscal root tears.

Arthroscopic Treatment of a “Bucket-Handle Like Tear” Lesion of the Medial Meniscus

Menisci are involved in providing shock absorption, knee stability, and load transfer. Age, tear pattern, location, size and extent, repair time and technique, and patient habits are among various factors that affect meniscal healing. Meniscus repair has become the procedure of choice for the treatment of meniscal tears. However, treatment of meniscal tears in patients over 40 years of age is still debatable. Rare patterns of lesions have been described in the literature. We report a zone 2, partial thickness, “bucket-handle like tear” medial meniscal lesion with two attached ends in a 48-year-old male patient with persistent symptoms after six months of conservative treatment. Arthroscopic excision and debridement were performed. At a six-month follow-up, the patient regained 90% of his functional capacity.

Complex Meniscus Tears Treated with Collagen Matrix Wrapping and Bone Marrow Blood Injection: Clinical Effectiveness and Survivorship after a Minimum of 5 Years' Follow-Up

Purpose. To determine the 5-year success rate of the "all-inside" technique of arthroscopic meniscus suture and collagen membrane wrapping along with bone marrow blood injection, to evaluate the progression of degenerative changes and the impact of simultaneous anteriro cruciate ligament (ACL) reconstruction. Methods. Fifty-four consecutive patients with complex meniscal tears were treated with the previously described technique. The subjective scores (International Knee Documentation Committee 2000, Lysholm, EQ-5D-5L) and Barret clinical criteria of meniscal healing were recorded. Magnetic resonance images (MRIs) were assessed at 2 and 5 years postoperatively, using the Whole-Organ Magnetic Resonance Imaging Score (WORMS) criteria. Kaplan-Meier survival analyses were performed in order to assess the survivorship after the index procedure. Thirty-nine patients were divided into 2 groups: group A-isolated meniscus repair and group B-meniscus repair with concurrent ACL reconstruction. Results. Fifty-four patients were treated and 44 were available for analysis. There was a statistically significant improvement in subjective scores and clinical assessment between the preoperative, 2-year follow-up, and 5-year follow-up time points. EQ-5D-5L utility value was 0.9 ± 1 at final follow-up. The WORMS osteoarthritis severity grade had increased from 6.9 ± 5.0 points at the 2-year follow-up to 11.1 ± 9.6 points at the 5-year follow-up (P < 0.001). There was a significant difference between the groups after 60 months. The overall survival rate at final follow-up was 88%. Conclusions. The treatment option evaluated in this study has shown very good mid-term clinical and MRI-based outcomes as well as a favorable survival rate. Simultaneous ACL reconstruction is likely a factor for osteoarthritis progression.

Age-Related Changes in the Microvascular Density of the Human Meniscus

BACKGROUND

The microvascular anatomy of the meniscus of the human knee is regarded as a crucial factor in the injury response. Previous studies have investigated the zone-dependent distribution pattern, but no quantitative data exist on vascular density and its age-related changes.

HYPOTHESIS/PURPOSE

The aim of the present study was to histologically analyze the vascular anatomy of the meniscus as a function of age. It was hypothesized that vascular density would decrease with increasing age.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Human menisci were retrieved from patients who underwent tumor resection or who received total knee replacement because of osteoarthritis. A total of 51 menisci were collected from 28 patients over 9 years (mean age, 25.6 ± 20.4 years; range 3-79 years). Immunohistological staining (alpha-smooth muscle actin) in combination with serial sections and standardized software-based contrast detection were used for the quantitative analysis. Data were analyzed using multiple t tests and the analysis of variance for trends, with a statistical significance level of P < .05.

RESULTS

The overall vascular density in the meniscus was lower in the 61- to 80-year age group than in the age groups of 0 to 10, 11 to 20, and 21 to 30 years (P < .01). A negative linear trend was detected with increasing age (slope, -0.007; P = .016). Within the red-white (RW) zone, a low vessel density was detected for the age groups of 0 to 10 and 11 to 20 years. Beyond these age groups, no vasculature was found in the RW zone. For the white-white (WW) zone, no vessel formations were noted in any age group. Almost 95% of the vessels in the meniscus were located in the capsule.

CONCLUSION

This study reports quantitative histological data for microvascular anatomy as a function of age in a broad cohort of human knee menisci. The overall vascular density decreased with increasing age. No vessel formations were detected in the RW and WW zones after adolescence. Additionally, the capsule is far more densely vascularized than any other part of the meniscus.

CLINICAL RELEVANCE

Vascular density might be an additional factor to consider, along with tear location and patient age, for future treatment options.

Clinical and Radiological Outcomes After Isolated Anterior Horn Repair of Medial and Lateral Meniscus at 24 Months' Follow-up, With the Outside-In Technique

Background

The effects of repair of isolated anterior horn meniscus lesions have not been thoroughly described in the literature. We aimed to evaluate outcomes with subjective clinical scores and imaging modalities after repair of isolated anterior horn tears, at 24 months’ follow-up.

Methods

Records of all patients that opted for surgical repair of isolated, anterior horn tears of the medial and lateral meniscus were retrospectively reviewed, between 2016 and 2018. All patients were treated with arthroscopic outside-in technique by the same surgeon. Preoperative and postoperative clinical files were accessed to recover records of preoperative symptomatology, patient-reported scores [International Knee Documentation Committee (IKDC) rating, Lysholm score and Tegner activity level], preoperative and postoperative MRI data and time from injury to surgery.

Results

Mean age of eight patients was 25.25 years (range 18-37 years). Diagnostic preoperative MRI revealed isolated anterior horn tear of the lateral meniscus and medial meniscus in five patients and an isolated anterior horn tear of the medial meniscus in three patients. Mean time from injury to surgical repair was 23.75 days (range 7-43). We considered seven out of eight repairs to be successfully healed. At 24 months’ follow-up: Mean Lysholm score was 92.25 (range 89-95), Tegner activity scale score was 6.5 (range 5-8) and IKDC score was 91.78 (range 87.8-94.4). All scores significantly improved compared to preoperative values (p<0.001).

Conclusions

Outside-in is a reliable technique to repair meniscal anterior horn tears, both medially and laterally, with high healing rates and patient satisfaction in young, active patients.

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.

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.

Use of the forgotten joint score (FJS)-12 to evaluate knee awareness after isolated anterior cruciate ligament reconstruction with and without meniscus repair or partial meniscectomy

PURPOSE

The aim of this study was to compare knee awareness, based on the FJS-12 score, among three patient groups: Anterior cruciate ligament reconstruction (ACLR), ACLR + meniscus repair and ACLR + partial meniscectomy. The relationship between FJS-12 scores and scores on other instruments (Lysholm Knee Scoring Scale, Tegner Activity Level Scale, KOOS and WOMAC) was also evaluated.

METHODS

Forty-three patients were divided into group A (isolated ACLR) group B (ACLR + meniscectomy) and group C (ACLR + meniscus repair). Graft thickness, femoral tunnel width, tibial tunnel width, tibial screw thickness and follow-up time were evaluated in all three groups. The subjective knee scores (KOOS, WOMAC, Lysholm Knee Scoring Scale, Tegner Activity Level Scale and FJS-12) of the groups were then compared.

RESULTS

FJS-12 scores of 43 patients were evaluated. The mean age was 26.1 ± 6.5 years (range: 18-40 years). Group A: 23; group B: 9 and group C include 11 patients. The mean FJS-12 score of group B (median: 100 [range: 98-100]) was higher than that the others. Spearman's rho test showed that the FJS-12 is highly compatible with the other scores.

CONCLUSION

According to this study, FJS-12 and the other scoring systems showed that ACLR with partial meniscectomy is the most effective surgical method to restore normal sensation in the knee.

The Role of Collagen-Based Biomaterials in Chronic Wound Healing and Sports Medicine Applications

Advancements in tissue engineering have taken aim at treating tissue types that have difficulty healing naturally. In order to achieve improved healing conditions, the balance of exogenous matrix, cells, and different factors must be carefully controlled. This review seeks to explore the aspects of tissue engineering in specific tissue types treated in sports medicine and advanced wound management from the perspective of the matrix component. While the predominant material to be discussed is collagen I, it would be remiss not to mention its relation to the other contributing factors to tissue engineered healing. The main categories of materials summarized here are (1) reconstituted collagen scaffolds, (2) decellularized matrix tissue, and (3) non-decellularized tissue. These three groups are ordered by their increase in additional components beyond simply collagen.

Assessing the Resident Progenitor Cell Population and the Vascularity of the Adult Human Meniscus

PURPOSE

To identify, characterize, and compare the resident progenitor cell populations within the red-red, red-white, and white-white (WW) zones of freshly harvested human cadaver menisci and to characterize the vascularity of human menisci using immunofluorescence and 3-dimensional (3D) imaging.

METHODS

Fresh adult human menisci were harvested from healthy donors. Menisci were enzymatically digested, mononuclear cells isolated, and characterized using flow cytometry with antibodies against mesenchymal stem cell surface markers (CD105, CD90, CD44, and CD29). Cells were expanded in culture, characterized, and compared with bone marrow-derived mesenchymal stem cells. Trilineage differentiation potential of cultured cells was determined. Vasculature of menisci was mapped in 3D using a modified uDisco clearing and immunofluorescence against vascular markers CD31, lectin, and alpha smooth muscle actin.

RESULTS

There were no significant differences in the clonogenicity of isolated cells between the 3 zones. Flow cytometry showed presence of CD44⁺CD105⁺CD29⁺CD90⁺ cells in all 3 zones with high prevalence in the WW zone. Progenitors from all zones were found to be potent to differentiate to mesenchymal lineages. Larger vessels in the red-red zone of meniscus were observed spanning toward red-white, sprouting to smaller arterioles and venules. CD31⁺ cells were identified in all zones using the 3D imaging and co-localization of additional markers of vasculature (lectin and alpha smooth muscle actin) was observed.

CONCLUSIONS

The presence of resident mesenchymal progenitors was evident in all 3 meniscal zones of healthy adult donors without injury. In addition, our results demonstrate the presence of vascularization in the WW zone.

CLINICAL RELEVANCE

The existence of progenitors and presence of microvasculature in the WW zone of the meniscus suggests the potential for repair and biologic augmentation strategies in that zone of the meniscus in young healthy adults. Further research is necessary to fully define the functionality of the meniscal blood supply and its implications for repair.

Return-to-Play and Rehabilitation Protocols Following Isolated Meniscal Repair-A Systematic Review

Purpose

To systematically review the literature and assess the reported rehabilitation protocols, return-to-play guidelines, and reported rates of return-to-play after meniscal repair.

Methods

MEDLINE, EMBASE, and the Cochrane Library were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify studies on meniscal repair. Studies were included if return-to-play data and/or rehabilitation protocols were reported. The rate and timing of return-to-play was assessed. The rehabilitation protocols were documented, in addition to when to start range of motion (ROM), full ROM, partial weight-bearing (WB), and full WB.

Results

Overall, 88 studies met our inclusion criteria. Thirteen studies, including 507 patients, cited a range of 71.2% to 100% of return-to-play, with 53.9% to 92.6% returning to the same/greater level, ranging between 3.3 and 10 months. There was considerable variability in the reported rehabilitation protocols, but the most frequently reported time to begin ROM exercises was within the first week (78.9%) and full ROM at 6 weeks (33.3%). Partial WB was typically begun during the first week (61.0%), and full WB between the fourth and sixth week (65.6%) postoperatively. Following surgery, time elapsed was the most commonly cited criteria for return-to-play (97.0%), with 6 months being the most common time point applied (46.9%). No study advised against returning to competitive or contact sports after meniscal repair.

Conclusions

In conclusion, there was a high rate of return-to-play following meniscal repair, with 60% of patients returning to the same level of play. However, there was considerable diversity in the reported rehabilitation protocols and insufficient reporting on return-to-play criteria in the literature. This demonstrates the need for further research and formulation of an evidence-based consensus statement for this patient population.

Level of Evidence

Level IV, systematic review of Level I to IV studies.

Hybrid Inside-Out-Outside-In Meniscal Repair Through a Small Skin Incision

Although the updated generation of all-inside devices for meniscal repair is more convenient to deploy and can provide comparable clinical outcomes with those of the inside-out procedure, the latter is still a very useful technique, giving many advantages over the former. The critical drawback of the conventional inside-out technique is the need for preparation of the accessory incision to prevent the risk of soft-tissue entrapment and neurovascular injury while retrieving the exiting meniscal needles, especially at the posterior corner of the knee. To minimize the space volume of the incision, a small, bluntly dissected track guided by the first exiting meniscal needle is sufficient in our hybrid inside-out-outside-in technique. The guiding cannula for the first meniscal needle passage is a commercial inside-out device, whereas the guiding cannula for retrieval in the subsequent meniscal needle passages is a spinal needle applied in an outside-in manner via the small track. Subsequent meniscal needles can be inserted in an inside-out or outside-in manner according to the design of the suture construct.

Microvascular Anatomy and Intrinsic Gene Expression of Menisci From Young Adults

BACKGROUND

Meniscal vascular supply is an important determinant of its healing potential. It has been reported that only the peripheral 30% of the meniscus is vascularized in cadavers aged 53 to 94 years; however, the vascularity in young patients, in whom meniscal repair is more often performed, is unknown.

PURPOSE

The primary objective was to analyze and measure the microvascular anatomy of the meniscus in adult cadaveric specimens <35 years old. The secondary objective was to assess angiogenic potential by quantifying regional gene expression in a meniscal allograft cohort <45 years old.

STUDY DESIGN

Descriptive laboratory study.

METHODS

In part 1 of this study, 13 fresh-frozen cadaveric knees (age range, 22-34 years; mean, 28.5 years) underwent popliteal artery India ink injection and tissue clearing using a Spalteholz technique, followed by microvascular vascular measurement. In part 2, mRNA was isolated from 13 meniscal allografts (age range, 17-43 years; mean, 27.2 years), and expression of angiogenic genes, vascular endothelial growth factor (VEGF), and vascular endothelial growth factor receptor 1 (FLT1) was quantified using real-time polymerase chain reaction.

RESULTS

The maximal depth of vascular penetration into the periphery of the medial and lateral menisci ranged from 0% to 42% and 0% to 48%, respectively. There was variation in the degree of vascular penetration within the medial meniscus, with the posterior horn having a significantly smaller depth of penetration (median, 8.7%) than that of the anterior horn (median, 17.4%; P < .0001) or midbody (median, 17.5%; P = .0003). There were no differences in angiogenesis gene expression (VEGF/FLT1) based on circumferential or radial meniscal locations.

CONCLUSION

The vascular supply of the medial and lateral menisci in specimens from adults <35 years of age extended farther than what was reported in specimens from older individuals; however, median values remained consistent. Gene expression of the angiogenic marker VEGF was low throughout all regions of uninjured menisci from young adults, which is consistent with reports in older specimens.

CLINICAL RELEVANCE

Improved understanding of meniscal vascular supply in young adults is critical to informing clinical treatment decisions.

Evidence-based Risk Stratification for Sport Medicine Procedures During the COVID-19 Pandemic

Orthopaedic practices have been markedly affected by the emergence of the COVID-19 pandemic. Despite the ban on elective procedures, it is impossible to define the medical urgency of a case solely on whether a case is on an elective surgery schedule. Orthopaedic surgical procedures should consider COVID-19-associated risks and an assimilation of all available disease dependent, disease independent, and logistical information that is tailored to each patient, institution, and region. Using an evidence-based risk stratification of clinical urgency, we provide a framework for prioritization of orthopaedic sport medicine procedures that encompasses such factors. This can be used to facilitate the risk-benefit assessment of the timing and setting of a procedure during the COVID-19 pandemic.

Meniscal Tears: Current Understanding, Diagnosis, and Management

From once being labelled as a functionless remain of leg muscle, extensive scientific investigations in recent decades have described the meniscus as one of the most crucial structures of the knee. The incidence of meniscal injuries is on the rise and can be attributed to the increased participation of youth in sporting activities. MRI continues to be the imaging modality of choice, and surgical management is the mainstay of treatment for meniscal tears. Arthroscopic partial meniscectomy (APM) is currently the most performed orthopedic procedure around the globe. However, recent studies have conclusively shown that outcomes after an APM are no better than the outcomes after a sham/placebo surgery. Meniscal repair is now being touted as a viable and effective alternative. Meniscal repair aims to achieve meniscal healing while completely avoiding the adverse effects of partial meniscectomy. Meniscal repairs have grown in popularity over the past three decades and have proved to be a much more efficient alternative to partial meniscectomy. It is now increasingly recommended to attempt meniscal repair in all repairable tears, especially in young and physically active patients. Partial Meniscal implants have also shown excellent outcomes in long-term studies, but its efficacy in acute settings still requires further research. Research performed on various techniques of meniscal regeneration looks promising, and regenerative medicine appears to be the way forward. This review aims to critically discuss the current understanding of the meniscus, its role in biomechanics of the knee joint, and the current methods used to diagnose and manage meniscal tears.