Predictive Factors for Failure of Meniscal Repair: A Retrospective Dual-Center Analysis of 918 Consecutive Cases

Redefining Failure: Criteria for Unsuccessful Outcomes in Meniscus Repair

PURPOSE OF REVIEW

Meniscus repair plays a critical role in preserving knee function and delaying degenerative changes after a meniscus tear. Despite advancements in surgical techniques, there remains significant variability in how outcomes are defined and reported. This review examines the evolving interplay between traditional metrics of success such as reoperation rates, radiographic healing, etc., and the more subjective patient reported outcome measures (PROMs).

RECENT FINDINGS

Recent findings highlight the discrepancies between radiographic healing, symptomatic relief, and functional improvement. While reoperation rates remain a widely used failure criterion, they do not account for patients who avoid revision surgery despite persistent symptoms. MRI assessments can detect incomplete healing, but imaging abnormalities do not always correlate with clinical dysfunction. PROMs and return-to-sport (RTS) rates offer valuable insight into functional recovery, yet they vary across studies and may not always reflect anatomical failure. Emerging consensus supports a dual model: anatomical failure, which reflects structural compromise seen on imaging or second-look arthroscopy, and clinical failure, which includes persistent symptoms, limited function, or poor patient-reported outcomes regardless of imaging results. Meniscus repair failure should be assessed using a multidimensional approach, incorporating structural integrity, symptom persistence, functional performance, and patient satisfaction. Standardizing failure definitions will improve data comparability, enhance treatment strategies, and guide patient expectations. Future research should refine composite failure models and integrate meniscus-specific PROMs to optimize long-term outcomes. By redefining failure, clinicians can improve surgical success rates and provide more personalized, evidence-based care.

TAKEAWAY

Not all healed menisci function well, and not all unhealed ones fail. By redefining failure, we can reframe success-and better serve patients.

Knee Injuries in Baseball

While knee injuries account for just 7% of injuries in professional and collegiate baseball, they are the fourth most common cause of missed professional games. The 3 most common knee-related issues in baseball are patellar tendinopathy, meniscus tears, and medial collateral ligament sprains. While injuries such as anterior cruciate ligament tears and patellar dislocations are less common, they are notable due to their potentially significant effect on time missed. Treatment considerations of all these pathologies are multifactorial and should include skeletal maturity, level of play, timing of season/recruiting, and long-term goals.

The management of isolated meniscal tears in skeletally immature children. An international expert consensus

PURPOSE

The prevalence and appreciation of meniscal tears in children have increased in both number and complexity. There is currently a paucity of high-quality evidence that can guide surgeons in treating skeletally immature patients with meniscal injuries. The aim of this study was to develop comprehensive recommendations for the management of isolated meniscal tears in skeletally immature children.

METHODS

An international, two-round, modified Delphi consensus was completed. Included 'experts' were identified as having an established adult knee practice, including children and either: (1) Faculty at an international paediatric knee conference, (2) Active members of complex national paediatric multi-disciplinary groups or (3) Members of faculty on recognised national/international instructional courses aimed at teaching the management of meniscal lesions to knee surgeons. The currently available literature was reviewed, and areas of poor quality, inconclusive or absent evidence were examined and formed the focus of the study. A threshold of 70% was used to define consensus for our study based on other similar Delphi consensus studies in the literature.

RESULTS

A total of 43 experts (Round 1) and 41 experts (Round 2) took part in the Delphi study, including surgeons from Europe, the United States of America and South America. 34 statements were identified exploring three main domains-clinical assessment, management and complex tears (bucket handle, discoid and radial). Following Round 1, consensus was reached on 17 (50%) statements; subsequently, after completion of Round 2, consensus was reached on 28 (82%) statements, leaving six (18%) with no consensus. The areas of no consensus included investigation of painless clicking, the most sensitive clinical test for meniscal pathology, treatment of small radial tears (less than 1/3 width), ability to reduce chronic bucket handle tears and timing of surgery.

CONCLUSIONS

This is the first modified Delphi consensus that provides evidence for surgeons treating skeletally immature children with isolated meniscal tears. A valuable level of consensus was reached on the assessment and management of simple and specialist meniscal tears. These consensus statements can both inform clinical practice and be used in the development of further high-quality research studies.

LEVEL OF EVIDENCE

Level V.

Failure rate of isolated medial meniscus repair in the stable knee: Systematic review and meta-analysis

PURPOSE

The present meta-analysis aims to determine the outcomes and failure rates for medial meniscus repairs in patients with stable knees.

METHODS

A literature search was conducted using PubMed and Scopus with the terms '(medial meniscus OR medial meniscal) AND (repair)'. The search strategy was based on the PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) protocol and included 93 articles assessed for eligibility. The search criteria were limited to studies reporting outcomes and failure rates. The exclusion criteria included languages other than English, biomechanical studies, letters to editors, non-full text, review articles, meta-analyses and case reports.

RESULTS

In total, 10 studies with 595 patients were included. Degenerative tears or studies reporting meniscus repair outcomes on root repairs, revision or primary anterior cruciate ligament reconstruction, discoid menisci or ramp lesions were excluded. All studies included revision surgery and/or clinical symptoms as failure definitions. The overall medial meniscal repair failure rate was 26% with a 95% confidence interval (CI) [15%-37%]. The mean time to failure from isolated medial meniscus repair surgery was 27.7 months with 95% CI [18.5-36.9 months]. The postoperative Lysholm and IKDC scores were reported in three articles. At the final follow-up, the mean postoperative Lysholm and IKDC scores were 92.3 with 95% CI [84.5-100] and 88.6 with 95% CI [83.5-93.8], respectively.

CONCLUSION

The current meta-analysis revealed an overall failure rate of 26% in the case of medial meniscus repair in a stable knee. For these reasons, the patient should be aware of the substantial risk of revision surgery (one out of four cases). Medial meniscus repair in a stable knee yielded good clinical results.

LEVEL OF EVIDENCE

Level II.

Clinical outcomes of repaired radial meniscal tears: A retrospective study with minimum 2-year follow-up

BACKGROUND

The management of meniscal radial tears has changed significantly in recent years in favor of meniscus repair. However, there is still limited published data on the outcomes and risk factors associated with repair failure. The objective of this study is to evaluate the clinical success rate of repaired meniscal radial tears and identify potential risk factors for failure.

METHODS

Patients who underwent repair of meniscal radial tears between 2016 and 2022 were reviewed retrospectively. The following parameters were collected: demographic data, pre-operative Kellgren-Lawrence grading, history of previous knee surgeries, time from injury to surgery, injury location, number of sutures used, use of transtibial tunnel augmentation, associated procedures, postoperative functional scores, and clinical failure rates.

RESULTS

81 patients were included, with a mean age of 29.9 ± 12.3 years. The mean follow-up time was 36.7 ± 17.0 months. Postoperatively, the mean IKDC was 81 ± 18.1, and the mean Lysholm score was 82 ± 18.4. The clinical failure rate was 19.8%. In the univariate analysis, the factors associated with failure included increased age, female gender, medial meniscus repair, isolated repairs (without ACL reconstruction), a Kellgren-Lawrence scale greater than 0, and repairs without a transtibial tunnel. However, none of these variables were statistically significant in the multivariate analysis adjusted for age and gender.

CONCLUSION

The clinical success rate of repaired meniscal radial tears was about 80% after a minimum 2-year follow-up. Increased age, female gender, repair of medial meniscus, isolated repair without ACL reconstruction, mild preoperative osteoarthritic signs, and repair without a transtibial tunnel augmentation are possible risk factors for failure.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Meniscal repair with concomitant suture-augmented ACL repair versus reconstruction: a retrospective cohort study

INTRODUCTION

This study evaluated patient-reported outcome measures (PROM) and reinjury rates in patients undergoing meniscal repair with concomitant suture-augmented (SA) anterior cruciate ligament reconstruction (ACLR) or repair (ACLr).

MATERIALS AND METHODS

We performed a retrospective cohort study of patients who underwent concomitant meniscus and ACL procedures by a single surgeon between 2015 and 2021. Inclusion criteria were meniscal repair with concomitant SA ACLR or SA ACLr, at least two years of follow-up, and participation in postoperative PROM surveys. Exclusion criteria were concomitant meniscectomy, multiligament repair or reconstruction, or other concomitant procedures at the time of the index operation. After a minimum of two years of follow-up, data was collected on reinjury and patient reported outcome measures, including Knee Injury and Osteoarthritis Outcome Score (KOOS), Single Assessment Numeric Evaluation (SANE), Visual Analog Pain Scale, and Veterans Rand 12 Item Survey (VR-12).

RESULTS

39 total patients were identified, 12 ACL repairs and 27 ACL reconstructions. 6 patients were lost to follow-up, with 10 patients in the ACLr cohort and 23 patients in the ACLR cohort included in the study. Meniscus tear laterality was not significantly different between the cohorts (p = 0.3828). There were two meniscal repair failures in the ACLr cohort compared to one in the ACLR cohort (p = 0.2117). There was one ACL reinjury in the ACLr cohort compared to zero reinjuries in the ACLR cohort (p = 0.3030). In a univariate analysis of PROMs, there were no significant differences in postoperative KOOS (p = 0.3308), VAS (p = 0.9955), SANE (p = 0.3449), VR-12M (p = 0.4705), or VR-12P (p = 0.7903) scores between the cohorts. In a multivariable analysis controlling for age, sex, BMI, meniscus tear laterality, and meniscus tear pattern, choice of ACL procedure was not a significant predictor of any postoperative PROM. 23 total patients, 6 ACL repairs and 17 ACL reconstructions had preoperative data available and were evaluated for changes in PROMs after surgery. There were clinically significant improvements in KOOS and SANE scores in both cohorts postoperatively.

CONCLUSION

In this cohort of patients, meniscal repair with SA ACLr was not inferior to meniscal repair with SA ACLR at two years of follow-up.

Knee malalignment and laterality influence 2-year meniscus tear repair outcomes: A pilot study

PURPOSE

To analyse biomechanical determinants for radiological and clinical outcomes of posterior horn longitudinal vertical meniscal tear (LVMT) repairs.

METHODS

Patients undergoing primary repair of vascular zone traumatic full-thickness posterior horn LVMT were enroled. We hypothesized four potential factors would influence mid-term outcomes: malalignment (varus/valgus ≥5° for medial/lateral tears), meniscal laterality (medial vs. lateral), concomitant anterior cruciate ligament reconstruction (ACLR) and cartilage damage (Outerbridge grade ≥ II). The primary outcome was posterior horn nonhealing rate 6 months postoperatively (T1), evaluated using computed tomography arthrography (CTA) and Henning's criteria. Secondary outcomes were patient-reported outcomes measures (PROMs) assessed at T1 and ≥24 months postoperatively (T2). Univariate and multivariate logistic regression models estimated the marginal relative risk (MRR) of nonhealing for each determinant, while fractional logit regression assessed determinants' impact on PROMs at T1 and T2.

RESULTS

Seventy-eight patients (median age 29 years, interquartile range [IQR]: [21-37]); 76% male), were followed for ≥2 years (median 2.5 years, IQR: [2.1-3.6]). LVMTs extended to the middle horn in 81% and to the anterior horn in 52%. Posterior horn nonhealing rates (53%) were higher than in the middle (35%, p = 0.013) and anterior horn (7%, p < 0.001). Malalignment was present in 14%, medial meniscal involvement in 77%, ACLR in 55% and cartilage damage in 37%. Malalignment (MRR = 1.48, 95% confidence interval (CI): [0.84, 2.09]) and medial laterality (MRR = 1.7, 95% CI: [0.93, 3.6]) were independently identified as potential nonhealing risk factors. But it is the combination of varus malalignment and medial laterality that significantly increased the risk of nonhealing (MRR = 2.54, 95% CI: [1.09, 6.01], p = 0.033) and negatively impacted all Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales and International Knee Documentation Committee (IKDC) score at T1 and/or T2.

CONCLUSION

Combined varus malalignment and medial meniscus involvement strongly predicted repair nonhealing and poorer outcomes after posterior horn LVMT repair.

STUDY DESIGN

Prospective cohort pilot study.

LEVEL OF EVIDENCE

Level III.

High failure rate in meniscal repair when preceding anterior cruciate ligament reconstruction: An analysis of two-stage surgery for concomitant ACL injury and traumatic meniscus tear

PURPOSE

To investigate the failure rate, predictive factors associated with failure and clinical outcomes after a two-stage surgery; meniscus repair followed by subsequent anterior cruciate ligament (ACL) reconstruction (ACLR).

METHODS

Patients with a concomitant traumatic meniscus tear and ACL injury who underwent a two-stage surgery between January 2015 and January 2021 were identified. The primary outcome was meniscal repair failure, defined as a reoperation (re-repair or resection). A Cox-regression analysis was used in order to analyse factors associated with meniscal repair failure within 3 years after the primary surgery for a meniscal repair. Secondary outcomes were range of motion (ROM), anterior knee laxity and the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 1- and 2-year follow-up. The thresholds of patient acceptable symptom state (PASS), treatment failure (TF) and minimum important change (MIC) were applied to KOOS4 (mean score of the KOOS Pain, Symptoms, Sports/Rec and QoL subscales).

RESULTS

A total of 150 patients were included. The meniscal repair failure rate after 3 years was 36.7%. Failure of meniscal repair was significantly associated with a time interval >1 year between the meniscal repair to the ACLR (hazard ratio [HR] = 2.5; 95% confidence interval [CI] = 1.2-5.5; p < 0.01), medial meniscus repair (HR = 2.3; 95% CI = 1.6-3.4; P < 0.01), and female sex (HR = 1.42; 95% CI = 1.0-1.9; p = 0.01). The age of the patient was not associated with meniscal repair failure. At the 6-month follow-up, most patients (72.5%) showed less than 2 mm of knee laxity; four patients (6.7%) experienced loss of extension and four patients (1.7%) experienced loss of flexion. On the KOOS4, at the 2-year follow-up, PASS was achieved in 53.4%, TF occurred in 1.7%, and MIC was reached in 36.4% of patients.

CONCLUSION

The meniscus repair failure rate after the staged procedure was 36.7% at 3 years. A longer time interval from meniscal repair to ACLR, medial meniscus repair, and female sex were associated with an increased risk of meniscal repair failure. Age was not associated with meniscal repair failure.

LEVEL OF EVIDENCE

Level IV case series retrospective study.

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.

Enhancing meniscal repair with tough adhesive puncture sealing (TAPS) suture: A proof-of-concept study on bovine cadaveric knees

Purpose

The objective was to use cyclic tensile loading to compare the gap formation at suture site of three different suture materials to repair bovine radial meniscal tears: (1) polyglactin sutures, (2) tough adhesive puncture sealing (TAPS) sutures and (3) ultra-high molecular weight polyethylene (UHMWPE) sutures.

Methods

Twelve ex vivo bovine knees were dissected to retrieve the menisci. Complete radial tears were performed on 24 menisci, which were then separated into three groups and repaired using either pristine 2-0 polyglactin sutures, TAPS sutures (2-0 polyglactin sutures coated with adhesive chitosan/alginate hydrogels) or 2-0 UHMWPE sutures with a single stitch. The repaired menisci were clamped onto an Instron machine and underwent cyclic loading between 5 and 25 N at a frequency of 0.16 Hz. Gap formation between the edges of the tear was measured after 500 cycles using an electronic caliper, when the meniscus was still on the Instron without any load applied.

Results

Mean gap formation was 5.22 mm (±1.70) for the 2-0 polyglactin sutures, 2.48 mm (±0.25) for the TAPS sutures, and 4.85 mm (±1.55) for the 2-0 UHMWPE sutures. The gap was significantly smaller in the TAPS sutures group compared to the two others because of better force dispersion, decreasing tissue damage by suture indentation and potentially leading to better meniscal healing.

Conclusions

From a biomechanical standpoint, coated sutures held the edges of radial meniscal tears closer together compared to conventional sutures. This technology has the potential to reduce tissue damage and improve the success rate of meniscal repairs.

Level of Evidence

controlled laboratory study.

Assessment of four sterilization techniques for meniscal allograft transplantation in rabbits

Purpose

This study aimed to compare the effects of four sterilization techniques on meniscal allograft transplantation (MAT) in rabbits.

Methods

In total, 85 medial or lateral meniscuses were obtained from 22 adult New Zealand white rabbits. These 85 meniscal allografts were seeded with Staphylococcus aureus (S. aureus) and randomly divided into five groups (n = 17): iodine group, Cobalt-60 group, glutaraldehyde group, ethylene oxide group and control group. Bacterial colonies of the allografts were determined before (n = 7) and after (n = 7) sterilization. Histological features were analyzed using haematoxylin and eosin (H&E) staining (n = 3). An additional 50 medial or lateral meniscuses were taken from 13 adult New Zealand white rabbits, and they were kept fresh-frozen (-40°C) for 1 month. Subsequently, these 50 meniscuses were randomly divided into five groups, which were treated with iodine, Cobalt-60, glutaraldehyde, ethylene oxide and normal saline, separately (n = 10), and stored at -20°C before MAT. MAT was given to the knee joints of the right hind legs of 50 adult Japanese white rabbits. After 6 weeks of MAT, the transplanted meniscal allografts were taken for biomechanical test (n = 7) and H&E staining (n = 3).

Results

The results of the bacterial count indicated that the number of S. aureus colonies was less than 1 colony-forming unit (CFU)/allograft in all five groups after sterilization, except for the control group (415 CFU/allograft). H&E staining revealed that allografts in the iodine group presented the complete structure; allografts in the Cobalt-60 and glutaraldehyde groups were preserved relatively well; and allografts in the control and ethylene oxide groups were severely destructed, especially in the ethylene oxide group. Using the transplanted allografts, the biomechanical test showed that the maximum load of allografts in each group was significantly different, with ethylene oxide effective sterilization agents being used for disinfecting meniscal grafts (iodine group: 270.71 ± 62.81 N, Cobalt-60 group: 182.14 ± 71.29 N, glutaraldehyde group: 254.29 ± 31.55 N, ethylene oxide group: 40.00 ± 22.73 N and control group: 183.14 ± 76.40) (p ≤ 0.001). H&E staining with transplanted allografts revealed that allografts in the iodine group had the most intact structure; allografts in the Cobalt-60 and glutaraldehyde groups presented a relatively intact structure; and allografts in the control and ethylene oxide groups were seriously damaged, especially in the ethylene oxide group.

Conclusion

It was found that iodine, Cobalt-60, glutaraldehyde and ethylene oxide are effective sterilization agents for disinfecting meniscal grafts. Iodine exhibited superior preservation of both the biomechanics and structural integrity of the meniscal allografts, whereas ethylene oxide caused the most severe destruction to the meniscal allografts.

Level of Evidence

Not applicable because this is an animal study.

Does concomitant meniscus repair and meniscectomy show different efficacy in anterior cruciate ligament reconstruction? A systematic review and meta-analysis

Aims

Currently, it is advised to perform meniscal repair instead of meniscectomy in certain cases of primary anterior cruciate ligament reconstruction (ACLR). However, the level of evidence is low. Therefore, this study aimed to compare the effectiveness of meniscectomy and meniscus repair in addition to ACLR.

Methods

The systematic search was conducted in three online databases (EMBASE, MEDLINE, and Cochrane) from inception until October 2021 for the literature on primary ACLR and concomitant meniscal surgery. Eligible studies compared the following outcomes between meniscal repair and meniscectomy groups: the Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score, International Knee Documentation Committee (IKDC) score, and KT-arthrometer examinations. Lastly, we calculated pooled mean differences (MDs) with 95 % confidence intervals (CIs) from the change between pre- and post-intervention values.

Results

Of 10,565 studies, 22 met the inclusion criteria, with a follow-up between 6 and 43 months. We found no difference when comparing the KOOS subscale changes-only in the KOOS pain subscale (MD = -1.6; CI: -2.48, -0.72). However, these results were not clinically significant. We analyzed the lateral and media meniscal injuries separately and concluded the same results regarding KOOS changes. We found no significant differences in the Lysholm score change (MD = -2.61; CI: -5.51, 0.29), changes in IKDC score (MD = 1.08; CI: -4.05, 6.21) or the change for the KT-arthrometer side-to-side difference (MD = -0.50; CI: -1.06, 0.06).

Conclusion

Based on our result, we did not find a clinically significant difference between meniscus repair and meniscectomy during primary ACLR regarding patient-reported outcomes in a short-term follow-up.

Translational potential

Our research supports the prompt integration of findings into clinical practice for treating meniscus injuries during ACL reconstruction. We recommend considering both meniscus repair and meniscectomy, as the available data indicate their effectiveness. Further studies are necessary to assess the long-term impacts, particularly on osteoarthritis, and to identify patient subgroups that may benefit most from each technique.

How to Improve Meniscal Repair through Biological Augmentation: A Narrative Review

Since the role of the menisci in knee stability, proprioception, and homeostasis has been well established, significant efforts have been made to repair meniscal tears, resulting in excellent clinical outcomes and a reduction in the progression of knee osteoarthritis (OA). However, varying failure rates have been reported, raising questions regarding the healing potential in cases of complex injuries, poorly vascularized and degenerated areas, and generally in the presence of unfavorable biological characteristics. Therefore, over the last few decades, different strategies have been described to increase the chances of meniscal healing. Biological augmentation of meniscal repair through various techniques represents a safe and effective strategy with proven clinical benefits. This approach could reduce the failure rate and expand the indications for meniscal repair. In the present study, we thoroughly reviewed the available evidence on meniscal repair surgery and summarized the main techniques that can be employed to enhance the biological healing potential of a meniscal lesion. Our aim was to provide an overview of the state of the art on meniscal repair and suggest the best techniques to reduce their failure rate.

Systematic Review and Meta-analysis of Clinical Outcomes Following Meniscus Repair in Patients 40 Years and Older

Background

Meniscal repair has been associated with long-term benefit in patients compared with meniscectomy. As a generalization, meniscal repair in older patients is less likely to be successful, leading to reduced adoption of meniscal repair compared with younger patients.

Purpose

To establish the clinical performance of meniscal repair in "older" patients (age, ≥40 years) and compare it with performance in "younger" patients (age, <40 years).

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic literature review was performed in September 2021 using Embase and PubMed to identify published English-language studies that reported on a meniscal repair in >5 patients aged ≥40 years. Outcomes of interest were success/failure rate (as defined by the study), revision meniscal procedure rate, and patient-reported outcomes. Meta-analyses were used to synthesize outcomes across all studies in older patients. Meta-analyses were also used to compare outcomes between older and younger patients across studies, providing data on both age groups.

Results

Fourteen studies were identified. Meniscal repair in older patients was determined to have a failure rate of 12% (95% CI, 7.3% to 19.4%) and a revision meniscal procedure rate of 9.8% (95% CI, 6.2% to 15.0%). The postoperative Lysholm score was 86.7 (95% CI, 81.7 to 91.7). No statistically significant differences were observed between older and younger patients in failure rate (relative risk [RR], 0.73 [95% CI, 0.44 to 1.21]; P = .2205), revision meniscal procedure rate (RR, 0.69 [95% CI, 0.41 to 1.16]; P = .1613), or Lysholm scores (mean difference, 2.3 [95% CI, -4.7 to 9.2]; P = .5278, 4 studies).

Conclusion

Meniscal repair in selected patients aged ≥40 years resulted in good success rates and patient-reported outcome measures, which appear similar to those reported for patients aged <40 years. Therefore, meniscal repairs can be performed in at least a specific portion of "older" patients, and age per se should not be the sole determining factor in whether to perform a meniscal repair.

Emerging biologic augmentation strategies for meniscal repair: a systematic review

BACKGROUND

Meniscal repair should be the gold standard. However, the meniscus is poorly vascularized and even an excellent meniscus repair may not heal. Therefore, numerous studies and systematic reviews have been carried out on platelet-rich plasma (PRP), mesenchymal stem cells (MSCs) and fibrin clots for meniscal augmentation, but the results remain controversial. This systematic review aimed to identify other emerging strategies for meniscal repair augmentation and to assess whether there are different avenues to explore in this field.

METHODS

A systematic literature review was conducted in August 2022. PubMed, Ovid MEDLINE(R) all, Ovid All EBM Reviews, Ovid Embase and ISI Web of Science databases were searched. In Vivo animal and human studies concerning the biological augmentation of meniscal lesions by factors other than PRP, MSCs or fibrin clots were included. Cartilage-only studies, previous systematic reviews and expert opinions were excluded. All data were analyzed by two independent reviewers.

RESULTS

Of 8965 studies only nineteen studies covering 12 different factors met the inclusion criteria. Eight studies investigated the use of growth factors for meniscal biologic augmentation, such as vascular endothelial growth factor or bone morphogenic protein 7. Five studies reported on cell therapy and six studies focused on other factors such as hyaluronic acid, simvastatin or atelocollagen. Most studies (n = 18) were performed on animal models with gross observation and histological evaluation as outcomes. Polymerase chain reaction and immunohistochemistry were also common. Biomechanical testing was the object of only two studies.

CONCLUSIONS

Although several augmentation strategies have been attempted, none has yielded conclusive results, testifying to a lack of understanding with regard to meniscal healing. More research is needed to better understand the pathways that regulate meniscus repair and how to act positively on them.

LEVEL OF EVIDENCE

Systematic review of case-control and animal laboratory studies.

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.

An All-Suture-Based Technique for Meniscal Repair Is Cost-Effective in Comparison to Partial Meniscectomy for Horizontal Cleavage Tears

Purpose

To determine the cost-effectiveness of meniscal repair (MR) using an all-suture-based technique when compared to partial meniscectomy (PM) for horizontal cleavage tears (HCTs) from a payor's perspective in the United States.

Methods

A state-transition model and cost-utility analysis were developed from a US payor's perspective to project treatment costs and quality-adjusted life-years (QALYs) in a cohort of 35-year-old patients without osteoarthritis at baseline and presenting with either a lateral or medial HCT. Two outpatient costing perspectives were used, namely ambulatory surgical centers (ASCs) and hospitals. The state-transition model had 7 health states with transition probabilities, costs, and utilities obtained from the existing literature. Cost-effectiveness was assessed using a willingness-to-pay threshold of $100,000/QALY, and sensitivity analysis considered the effects of parameter uncertainty on model results. MR failure rates were focused on an all-suture-based technique; however, in a separate scenario, this study considered effectiveness data from various MR techniques and devices.

Results

MR dominated PM over a lifetime horizon, increasing QALYs by 0.43 per patient and decreasing the cost by $12,227 per patient within a hospital setting (and by $12,570 within an ASC). MR with an all-suture-based technique continued to be the dominant treatment when age at primary treatment was varied between 30 and 60 years. Sensitivity analysis showed that MR was not cost-effective in year 1, was cost-effective from year 2, and was cost-saving from year 6 onward from both ASC and hospital perspectives. Probabilistic sensitivity analysis found that MR was cost-effective over a lifetime horizon in 99% of 10,000 iterations on base-case analysis.

Conclusions

Using a lifetime horizon, this study found that from a payor's perspective, MR is a cost-saving intervention when compared with PM in patients with an HCT.

Level of Evidence

Level III, economic analysis.

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.

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.

Clinical outcome of iterative meniscal suture after ACL reconstruction at a minimum of 2 years' follow-up

INTRODUCTION

Failure rates in meniscal suture associated to ACL reconstruction range from 10 to 26.9%, often leading to meniscectomy. In young patients, the wish to conserve the meniscus may lead to iterative suture, if the lesion allows. There are no data available for clinical results of repeat meniscal suture at the same site as the primary lesion in a stabilized knee. The immediate socioeconomic cost, compared to meniscectomy, needs to be taken into account, and benefit needs to be demonstrated. The main aim of the present study was to assess the rate of secondary meniscectomy after iterative meniscal suture in stabilized knees. The study hypothesis was that failure rates are higher in iterative isolated meniscal suture after ligament reconstruction than in primary repair.

MATERIAL AND METHODS

This single-center retrospective study analyzed patients receiving iterative meniscal suture on stable knee, between 2009 and 2019, with a minimum 26 months' follow-up. Twenty-three patients were analyzed: 15 male, 8 female; mean age at iterative suture, 28.1±7.9 years (range, 14-49 years); mean BMI, 24.2±2.9kg/m2 (range, 19-31). Mean time to recurrence was 38.9±25.1 months (range, 6-93 months). Initial ACL graft used the patellar ligament in 69.6% of cases (n=16) and the hamstrings in 30.4% (n=7). Mean differential laximetry before iterative suture was 1.7±0.3mm (range, 1.2-2.3mm). Iterative suture was in the medial meniscus in 69.6% of cases (16/23) and in the lateral meniscus in 30.4% (7/23). Risk factors for failure, defined by requirement for meniscectomy, were assessed. Functional results were assessed on Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score and Tegner score.

RESULTS

The failure rate was 48% (11/23), incorporating all lesions together. Bucket-handle tear was most frequently associated with failure (91%; p<0.01). There was significant improvement after iterative suture in subjective IKDC score (51.6±15.2 vs. 81.3±15.6; p<0.001) and KOOS scores: symptoms and stiffness, 66.6±13.7 vs. 91.1±7.53 (p<0.001); pain, 79.2±12.7 vs. 93.4±7.4 (p<0.01); function, 91.3±11.2 vs. 97.9±4.44 (p<0.001); quality of life, 38.1±23.2 vs. 62.3±30.1 (p<0.001).

CONCLUSION

The failure rate for iterative meniscal suture on stabilized knee was 48%. Bucket-handle tear was a major risk factor for failure (91%). Despite these high failure rates, functional results systematically improved.

LEVEL OF EVIDENCE

IV.

Rates of subsequent surgeries after meniscus repair with and without concurrent anterior cruciate ligament reconstruction

OBJECTIVES

The purpose of this study was to compare the rates of secondary knee surgery for patients undergoing meniscus repair with or without concurrent anterior cruciate ligament reconstruction (ACLr).

METHODS

Utilizing a large national database, patients with meniscal repair with or without concurrent arthroscopic ACLr were identified. The two cohorts were then queried for secondary surgical procedures of the knee within the following 2 years. Frequency, age distribution, rates of secondary surgery, and type of secondary procedures performed were compared.

RESULTS

In total, 1,585 patients were identified: meniscus repair with ACLr was performed for 1,006 (63.5%) and isolated meniscal repair was performed for 579 (36.5%). Minimum of two year follow up was present for 487 (30.7% of the overall study population). Secondary surgery rates were not significantly different between meniscus repair with concurrent ACLr and isolated meniscus repairs with an overall mean follow up of 13 years (1.5-24 years) (10.6% vs. 13.6%, p = 0.126). For the 2 year follow up cohort, secondary surgery rates were not significantly different (19.3% vs. 25.6%, p = 0.1098). There were no differences in survivorship patterns between the two procedures, both in the larger cohort (p = 0.2016), and the cohort with minimum 2-year follow-up (p = 0.0586).

CONCLUSION

The current study assessed secondary surgery rates in patients undergoing meniscus repair with or without concurrent ACLr in a large patient database. Based on this data, no significant difference in rates of secondary knee surgery was identified.

Meniscal repair failure following concurrent primary anterior cruciate ligament reconstruction: results from the New Zealand ACL Registry

PURPOSE

This study aimed to identify the risk factors for meniscal repair failure following concurrent primary anterior cruciate ligament (ACL) reconstruction.

METHODS

Prospective data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation were reviewed. Meniscal repairs performed during concurrent primary ACL reconstruction were included. Repair failure was defined as a subsequent reoperation involving meniscectomy of the repaired meniscus. Multivariate survival analysis was performed to identify the risk factors for failure.

RESULTS

A total of 3,024 meniscal repairs were analysed with an overall failure rate of 6.6% (n = 201) at a mean follow-up of 2.9 years (SD 1.5). The risk of medial meniscal repair failure was higher with hamstring tendon autografts (adjusted HR [aHR] = 2.20, 95% CI 1.36-3.56, p = 0.001), patients aged 21-30 years (aHR = 1.60, 95% CI 1.30-2.48, p = 0.037) and in patients with cartilage injury in the medial compartment (aHR = 1.75, 95% CI 1.23-2.48, p = 0.002). The risk of lateral meniscal repair failure was higher in patients aged ≤ 20 years (aHR = 2.79, 95% CI 1.17-6.67, p = 0.021), when the procedure was performed by a low case volume surgeon (aHR = 1.84, 95% CI 1.08-3.13, p = 0.026) and when a transtibial technique was used to drill the femoral graft tunnel (aHR = 2.30, 95% CI 1.03-5.15, p = 0.042).

CONCLUSION

The use of a hamstring tendon autograft, younger age and the presence of medial compartment cartilage injury are risk factors for medial meniscal repair failure, whereas younger age, low surgeon volume and a transtibial drilling technique are risk factors for lateral meniscal repair failure.

LEVEL OF EVIDENCE

Level II.

High survival rate after the combination of intrameniscal and intraarticular infiltrations of platelet-rich plasma as conservative treatment for meniscal lesions

PURPOSE

To evaluate the efficacy of applying a combination of intrameniscal and intraarticular infiltrations of Platelet-Rich Plasma (PRP) in patients with meniscal tears, analyzing its failure rate and clinical evolution, as well as factors that may influence the positive response to this treatment.

METHODS

Three hundred and ninety-two cases out of 696 met the inclusion criteria and were included in this work. Survival and patient-reported outcome measure (PROM) were collected and analyzed. Survival rate was defined as the percentage of patients who did not undergo meniscus surgery during their follow-up time. Patients were asked to complete the Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline, 6 months and 18 months. Other patient- and pathology-related variables were collected. Blood and PRP samples were randomly tested as a quality control measure. Survival and comparative statistical tests, and multivariate regression were performed for the analysis of the variables.

RESULTS

The PRP applied had a platelet concentration factor of 1.9X in respect to blood levels, with no leukocytes or erythrocytes. Thirty-eight patients required surgical intervention after treatment reaching a survival rate of 90.3% with an estimated mean survival time of 54.4 months. The type of injury (P = 0.002) and the presence of chondropathy were risk factors for surgical intervention after PRP treatment (P = 0.043). All KOOS scores showed a significant statistical increase from baseline to 6 months (N = 93) and 18 months (N = 66) (P < 0.0001). The number of cases with minimal clinically important improvement (MCII) at 6 months and 18 months post-treatment was 65 (69.9%) and 43 (65.2%), respectively.

CONCLUSION

The combination of intrameniscal and intraarticular PRP infiltrations is a valid conservative treatment for meniscal injuries avoiding the need for surgical intervention. Its efficacy is higher in horizontal tears and decreases when joint degeneration is present.

LEVEL OF EVIDENCE

Level IV.

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.

The Efficacy of the Mulligan Concept to Treat Meniscal Pathology: A Systematic Review

Background

Meniscal pathologies are common knee injuries and arthroscopic surgery is the current accepted gold standard for treatment. However, there is evidence to support the use of the Mulligan Concept (MC) Mobilization with Movement (MWM) for meniscal pathologies including the 'Squeeze' technique, tibial internal rotation (IR), and tibial external rotation (ER).

Hypothesis/Purpose

The purpose of this systematic review was to critically appraise the literature to investigate the effectiveness of MC MWMs for meniscal lesions on patient reported pain, function, and multi-dimensional health status in patients with clinically diagnosed meniscal pathologies.

Study Design

Systematic Review.

Methods

A literature search was completed across multiple databases using combinations of the words "knee, function, mobilization with movement, MWM, mulligan concept, MC, meniscal pathology, meniscal derangement, and meniscal tear." Studies written within the prior 10 years that examined MC MWM techniques to treat knee meniscal injury were included. Articles that met the inclusion criteria (used MC MWM 'Squeeze' technique, tibial IR, or tibial ER for treatment of clinically diagnosed meniscal pathologies; Patient reported outcome [PRO] measures had to be used in the assessment of knee pain or function) were analyzed for quality. Randomized control trials were analyzed using the PEDro scale and the Downs & Black (D&B) checklist, case series were analyzed using the Joanna Briggs Institute (JBI) checklist, and case reports were analyzed using the CARES checklist.

Results

Six articles met the inclusion criteria and were included in this review, two randomized controlled studies, two case series, and two case reports consisting of 72 subjects. All six papers included reports of improvements in pain and function that were either statistically significant or met the minimal clinically important difference (MCID). Five studies reported the Disablement in the Physically Active (DPA) scale that also demonstrated statistically significant differences or met the MCID. The MC MWM 'Squeeze' technique, tibial IR, or tibial ER demonstrated the ability to reduce pain, improve function, and improve patient perceived disability following treatment of a clinically diagnosed meniscal pathology. These studies demonstrated short term results lasting from one week to 21 weeks.

Conclusion

Treatment interventions incorporating MC MWM techniques demonstrated reduction of pain and improvement in function in the short term in patients with clinically diagnosed meniscal pathologies.

Level of Evidence

2a.

In elite athletes with meniscal injuries, always repair the lateral, think about the medial! A systematic review

PURPOSE

This study aimed to evaluate and compare the time required to return to sports (RTS) after surgery, the rate of revision surgery and the time required for RTS after revision surgery in elite athletes undergoing meniscal repair or partial meniscectomy, particularly analysing the difference between medial and lateral menisci. It was hypothesised that both procedures would entail similar, high rates of RTS, with the lateral meniscus exhibiting higher potential healing postprocedure compared to the medial meniscus.

METHODS

A systematic review was conducted based on the PRISMA guidelines. Quality assessment of the systematic review was performed using the AMSTAR-2 checklist. The following search terms were browsed in the title, abstract and keyword fields: 'meniscus' or 'meniscal' AND 'tear,' 'injury' or 'lesion' AND 'professional,' 'elite' or 'high-level' AND 'athletes,' 'sports,' 'sportsman,' 'soccer,' 'basketball,' 'football' or 'handball'. The resulting measures extracted from the studies were the rate of RTS, level of RTS, complications, revision surgery and subsequent RTS, Tegner, International Knee Documentation Committee (IKDC) and Visual Analogue Scale (VAS).

RESULTS

In this study, the cohort consisted of 421 patients [415 (98.6%) men and 6 (1.4%) women] with a mean age of 23.0 ± 3.0 years. All patients were elite athletes in wrestling, baseball, soccer, rugby or handball. While 327 (77.7%) patients received partial meniscectomy at a mean age of 23.3 ± 2.6 years, 94 (22.3%) patients received meniscal repair at a mean age of 22.1 ± 4.0 years. After partial meniscectomy, 277 patients (84.7%) returned to their competitive sports activity and 256 (78.3%) returned to their pre-injury activity levels. A total of 12 (3.7%) patients required revision surgery because of persistent pain [5 (1.5%) patients], chondrolysis [2 (0.7%) patients] or both chondrolysis and lateral instability [5 (1.5%) patients]. Ten (83.3%) of the twelve patients had involvement of the lateral meniscus, whereas the location of injury was not specified in the remaining two patients. After revision surgery, all patients (100%) resumed sports activity. However, after meniscal repair, 80 (85.1%) athletes returned to their competitive sports activity and 71 (75.5%) returned to their pre-injury activity levels. A total of 16 (17.0%) patients required partial meniscectomy in cases of persistent pain or suture failure. Of these, 4 (25%) patients involved lateral and medial menisci each and 8 (50%) patients were not specified. After revision surgery, more than 80.0% of the patients (13) resumed sports activity.

CONCLUSIONS

In elite athletes with isolated meniscal injury, partial meniscectomy and meniscal suture exhibited similar rates of RTS and return to pre-injury levels. Nonetheless, athletes required more time for RTS after meniscal repair and exhibited an increased rate of revision surgery associated with a reduced rate of RTS after the subsequent surgery. For lateral meniscus tears, meniscectomy was associated with a high rate of revision surgery and risk of chondrolysis, whereas partial medial meniscectomy allowed for rapid RTS but with the potential risk of developing knee osteoarthritis over the years. The findings of this systematic review suggested a suture on the lateral meniscus in elite athletes because of the high healing potential after the procedure, the reduced risk of developing chondrolysis and the high risk of revision surgery after partial meniscectomy. Furthermore, it is important to evaluate several factors while dealing with the medial meniscus. If rapid RTS activity is needed, a hyperselective meniscectomy is recommended; otherwise, a meniscal suture is recommended to avoid accelerated osteoarthritis.

LEVEL OF EVIDENCE

Level IV.

STUDY REGISTRATION

PROSPERO-CRD42022351979 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=351979 ).

The role of patient characteristics and the effects of angiogenic therapies on the microvasculature of the meniscus: A systematic review

BACKGROUND

Considerable interindividual variation in meniscal microvascularization has been reported. The purpose of this review was to identify which patient characteristics affect meniscal microvascularization and provide a structured overview of angiogenic therapies that influence meniscal neovascularization.

METHODS

A systematic literature search was undertaken using PubMed, Embase, Web of Science, Cochrane library and Emcare from inception to November 2021. Studies reporting on (1) Patient characteristics that affect meniscal microvascularization, or (2) Therapies that induce neovascularization in meniscal tissue were included. Studies were graded in quality using the Anatomical Quality Assessment (AQUA) tool. The study was registered with PROSPERO(ID:CRD42021242479).

RESULTS

Thirteen studies reported on patient characteristics and eleven on angiogenic therapies. The influence of Age, Degenerative knee, Gender, and Race was reported. Age is the most studied factor. The entire meniscus is vascularized around birth. With increasing age, vascularization decreases from the inner to the peripheral margin. Around 11 years, blood vessels are primarily located in the peripheral third of the menisci. There seems to be a further decrease in vascularization with increasing age in adults, yet conflicting literature exists. Degenerative changes of the knee also seem to influence meniscal vascularization, but evidence is limited. Angiogenic therapies to improve meniscal vascularization have only been studied in preclinical setting. The use of synovial flap transplantation, stem cell therapy, vascular endothelial growth factor, and angiogenin has shown promising results.

CONCLUSION

To decrease failure rates of meniscal repair, a better understanding of patient-specific vascular anatomy is essential. Translational clinical research is needed to investigate the clinical value of angiogenic therapies.

Meniscal Repair Outcomes at Greater Than 5 Years: A Systematic Review and Meta-Analysis

BACKGROUND

The utilization of meniscal repair techniques continues to evolve in an effort to maximize the rate of healing. Meniscal repair outcomes at a minimum of 5 years postoperatively appear to better represent the true failure rates. Thus, a systematic review and meta-analysis of the current literature was conducted to assess the rate of failure at a minimum of 5 years after meniscal repair.

METHODS

We performed a systematic review of studies reporting the outcomes of meniscal repair at a minimum of 5 years postoperatively. A standardized search and review strategy was utilized. Failure was defined as recurrent clinical symptoms or a meniscal reintervention to repair or resect the meniscus in any capacity, as defined by the study. When reported, outcomes were assessed relative to anterior cruciate ligament (ACL) status, sex, age, and postoperative rehabilitation protocol. Meta-analyses were performed with a random-effects model.

RESULTS

A total of 27 studies of 1,612 patients and 1,630 meniscal repairs were included in this review and meta-analysis. The pooled overall failure rate was 22.6%, while the failure rate of modern repairs (excluding early-generation all-inside devices) was 19.5%. Medial repairs were significantly more likely to fail compared with lateral repairs (23.9% versus 12.6%, p = 0.04). Failure rates were similar for inside-out (14.2%) and modern all-inside repairs (15.8%). Early-generation all-inside devices had a significantly higher failure rate (30.2%) compared with modern all-inside devices (15.8%, p = 0.01). There was no significant difference in meniscal failure rate between repairs with concomitant ACL reconstruction (21.2%) and repairs in ACL-intact knees (23.3%, p = 0.54).

CONCLUSIONS

Modern meniscal repair had an overall failure rate of 19.5% at a minimum of 5 years postoperatively. Modern all-inside techniques appear to have improved the success rate of meniscal repair compared with use of early-generation all-inside devices. Lateral repairs were significantly more likely to be successful compared with medial repairs, while no difference was seen between patients undergoing meniscal repair with and without concomitant ACL reconstruction.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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.

Single-stage repair of displaced bucket-handle meniscal tears with anterior cruciate ligament reconstruction leads to good meniscal survivorship : a retrospective cohort study

AIMS

The best surgical strategy for the management of displaced bucket-handle (BH) meniscal tears in an anterior cruciate ligament (ACL)-deficient knee is unclear. Combining meniscal repair with ACL reconstruction (ACLR) is thought to improve meniscal healing rates; however, patients with displaced BH meniscal tears may lack extension. This leads some to advocate staged surgery to avoid postoperative stiffness and loss of range of motion (ROM) following ACLR.

METHODS

We reviewed the data for a consecutive series of 88 patients (mean age 27.1 years (15 to 49); 65 male (74%) and 23 female (26%)) who underwent single-stage repair of a displaced BH meniscal tear (67 medial (76%) and 21 lateral (24%)) with concomitant hamstring autograft ACLR. The patient-reported outcome measures (PROMs) EuroQol visual analogue scale (EQ-VAS), EuroQol five-dimension health questionnaire (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score (IKDC), and Tegner score were recorded at final follow-up. A Kaplan-Meier survival analysis was performed to estimate meniscal repair survivorship. Analyses were performed with different cut-offs for meniscal and ACL injury-to-surgery time (within three weeks, three to ten weeks, and more than ten weeks).

RESULTS

Meniscal repair survivorship at a median final follow-up of 55 months (interquartile range (IQR) 24 to 91) was 82% (95% confidence interval 70 to 89). A total of 13 meniscus repairs failed (12 requiring meniscectomy and one requiring a further meniscal repair). At final follow-up, median PROMs were: EQ-VAS 85 (IQR 75 to 90), EQ-5D Index 0.84 (IQR 0.74 to 1.00), KOOS Pain 89 (IQR 80 to 94), KOOS Symptoms 82 (IQR 71 to 93), KOOS Activities of Daily Living 97 (IQR 91 to 100), KOOS Sport and Recreation 80 (IQR 65 to 90), KOOS Quality of Life 69 (IQR 53 to 86), IKDC 82.8 (IQR 67.8 to 90.8), and Tegner 6 (IQR 4 to 7). Two patients underwent revision ACLR following further injuries. One patient had an arthroscopic washout for infection at 11 days post-BH meniscal repair/ACLR. Four patients (4.5%) required a further procedure for stiffness, reduced ROM, and pain, and all were operated on within three weeks of meniscal injury. There was no difference in the interval between meniscal injury and surgery between repairs that failed and those that survived.

CONCLUSION

These data suggest that concomitant ACLR with repair of displaced BH meniscal tears, even if they have been displaced for some time, appears to afford satisfactory PROMs and good survivorship. Repairs within three weeks of meniscal injury may be associated with higher rates of postoperative reintervention for stiffness. Cite this article: Bone Joint J 2022;104-B(6):680-686.

Outcomes, Complications, and Reoperations After Meniscal Allograft Transplantation

Background:

Outcomes following meniscal allograft transplantation (MAT) are an evolving topic.

Purpose:

To review clinical outcomes in younger, previously active patients who underwent an isolated MAT or MAT plus any osteotomy. Concurrent surgeries, complications, and graft survivorship are presented.

Study Design:

Case series; Level of evidence, 4.

Methods:

Inclusion criteria included having undergone MAT with a minimum of 1 year of follow-up with at least 1 of the following patient-reported outcome (PRO) measures collected pre- and postoperatively: visual analog scale for pain, Knee injury and Osteoarthritis Outcome Score (KOOS), the Western Ontario and McMaster Universities Arthritis Index, the 36-Item Short Form Health Survey, and overall satisfaction. From patient records, we recorded descriptive data, side (medial/lateral), previous or concurrent procedures, perioperative complications, revisions, and conversion to arthroplasty. Two-factor analysis of variance (ANOVA) was used to test for differences in age and body mass index (BMI). A 2 × 2 chi-square test was used to determine if the spectrum of procedures performed on our study’s patient group was representative of the entire population. PRO results were analyzed using a multivariate ANOVA.

Results:

From a total of 91 eligible patients, 61 (63 knees) met our inclusion criteria. Mean presurgery age was 25.5 ± 9.2 years, and mean BMI was 26.7 (range, 18.5-38.4). At follow-up (mean, 4.8 years; range, 1.0-13.6 years) overall PROs were statistically and clinically improved at final follow-up ( P ≤ .003); effect sizes were moderate and large. KOOS Pain and KOOS Activities of Daily Living showed some main or interaction effects that were trivial or small. Patient satisfaction with the treatment was ≥7 out of 10 in 85% of patients. A minimum of 1 subsequent surgery for various concerns was necessary in 23% of the 93 knees. Graft survival in the included patients was 100%.

Conclusion:

Complications (conditions requiring at least 1 subsequent surgery) affected about one-quarter of the patients who underwent MAT. Nevertheless, MAT seemed to provide our patients with adequate pain relief and improved function.

Failure and Complication Rates in Common Sports and Arthroscopic Procedures: Reality Check

Expectations following sports medicine and arthroscopic procedures have been elevated because of captivating modern-day media coverage of high-profile athletic injuries, surgery, and rapid return to sports. Unfortunately, this general perception may be misleading, and orthopedic sports medicine physicians must be aware of the harsh reality of the trials and tribulations associated with the subspecialty. The purpose of this review article is to provide an updated brief overview of the complications and failure rates associated with common arthroscopic procedures including rotator cuff repair, biceps tenodesis, Bankart procedure, Latarjet procedure, anterior cruciate ligament reconstruction, anterior cruciate ligament repair, meniscal repair, tibial tubercle osteotomy, and medial patellofemoral ligament reconstruction. Highlighting the complications is the first step toward early recognition, enhancing preventative measures, and successful management.

Nineteen percent of meniscus repairs are being revised and failures frequently occur after the second postoperative year: a systematic review and meta-analysis with a minimum follow-up of 5 years

PURPOSE

Meniscus repair has gained increasing interest over the last two decades as loss of meniscus tissue predisposes to early onset knee arthritis. Although there are many reports of meniscus repair outcome in short-term studies, data on the long-term outcome of meniscus repair are still scarce. The purpose of this meta-analysis was to evaluate the overall failure rate of meniscus repair with a minimum follow-up of 5 years. Additionally, possible factors influencing meniscus repair outcome were assessed.

METHODS

PubMed and Scopus were searched for studies of the last 20 years reporting on meniscus repair outcome with a minimum follow-up of 5 years. The study was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search terms used for this study were ([meniscus OR meniscal] AND repair). Titles and abstracts were evaluated by two authors independently. Using meta package of R (version 3.6.2), random-effect models were performed to pool failure rates. Subgroup analyses were performed and effect estimates in form of an odds ratio with 95% CIs were established.

RESULTS

In total, 12 studies with 864 patients were included. Degenerative tears were excluded in two studies and one study only included traumatic meniscus tears. Other studies did not state whether the cause of meniscus tear was degenerative or traumatic. Studies reporting meniscus repair outcome on root repairs, revision anterior cruciate ligament reconstruction, discoid menisci or ramp lesions were excluded. Revision surgery was used as failure definition in all included studies. The overall failure rate of meniscal repair at a mean follow-up of 86 months was 19.1%. There was no significant difference in meniscus repair outcome when performed in combination with anterior cruciate ligament reconstruction compared to isolated meniscus repair (18.7% vs. 28%; n.s.) or when performed on the lateral meniscus compared to the medial meniscus (19.5% vs. 24.4%; n.s.). There was no significant difference of meniscus repair outcome between vertical/longitudinal tears and bucket-handle tears (n.s.). Thirty-six percent of meniscus repair failures occur after the second postoperative year. The only significant finding was that inside-out repair results in a lower failure rate compared to all-inside repair (5.6% vs. 22.3%; p = 0.009) at 5 years.

CONCLUSION

The overall meniscus repair failure rate remains nineteen percent in long-term studies. The cause of failure is poorly documented, and it remains unclear whether failure of the meniscus repair itself or additional adjacent tears lead to revision surgery. Despite the given technical advantages of all-inside repair devices, this meta-analysis cannot demonstrate superior outcomes compared to inside-out or outside-in repair at 5 years.

LEVEL OF EVIDENCE

IV.

Failed meniscal repair increases the risk for osteoarthritis and poor knee function at an average of 9 years follow-up

PURPOSE

The purpose of this study was to determine the effect of meniscal repair on OA in the knee joint and patient-related outcomes.

METHODS

Three-hundred and sixteen meniscal repairs performed between 1999 and 2011 were analysed. Patient-related outcome measures were assessed through mailed questionnaires including KOOS, Lysholm score and Tegner activity level. Patients answering the questionnaires were encouraged to perform a radiographic evaluation with Rosenberg views, assessed according to Kellgren-Lawrence (KL) classification. The primary endpoint was to determine the effect of meniscal repair on the development of radiographic OA defined as a KL grade 2 or more.

RESULTS

Mean follow-up time was 9.3 years (SD 3.6), 162 (51%) patients answered the questionnaires, and 86 patients completed the X-ray. The odds ratio for OA with a failed meniscus repair was 5.1 (p = 0.007) adjusted for gender and age at time of follow-up. KOOS showed a clinically important difference in the sport and recreation subscale (p = 0.041).

CONCLUSIONS

There was an increased risk for OA in the affected compartment with a failed meniscus fixation. This supports the fact that the meniscus is an important protector of the cartilage in the knee. The meniscus injury affects the long-term health-related quality of life according to KOOS and in light of this study we recommend repair of a torn meniscus whenever possible.

LEVEL OF EVIDENCE

III.

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.

Anterior Cruciate Ligament Reconstruction With Concomitant Meniscal Repair: Is Graft Choice Predictive of Meniscal Repair Success?

Background

When meniscal repair is performed during anterior cruciate ligament (ACL) reconstruction (ACLR), the effect of ACL graft type on meniscal repair outcomes is unclear.

Hypothesis

The authors hypothesized that meniscal repairs would fail at the lowest rate when concomitant ACLR was performed with bone--patellar tendon--bone (BTB) autograft.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients who underwent meniscal repair at primary ACLR were identified from a longitudinal, prospective cohort. Meniscal repair failures, defined as any subsequent surgical procedure addressing the meniscus, were identified. A logistic regression model was built to assess the association of graft type, patient-specific factors, baseline Marx activity rating score, and meniscal repair location (medial or lateral) with repair failure at 6-year follow-up.

Results

A total of 646 patients were included. Grafts used included BTB autograft (55.7%), soft tissue autograft (33.9%), and various allografts (10.4%). We identified 101 patients (15.6%) with a documented meniscal repair failure. Failure occurred in 74 of 420 (17.6%) isolated medial meniscal repairs, 15 of 187 (8%) isolated lateral meniscal repairs, and 12 of 39 (30.7%) of combined medial and lateral meniscal repairs. Meniscal repair failure occurred in 13.9% of patients with BTB autografts, 17.4% of patients with soft tissue autografts, and 19.4% of patients with allografts. The odds of failure within 6 years of index surgery were increased more than 2-fold with allograft versus BTB autograft (odds ratio = 2.34 [95% confidence interval, 1.12-4.92]; P = .02). There was a trend toward increased meniscal repair failures with soft tissue versus BTB autografts (odds ratio = 1.41 [95% confidence interval, 0.87-2.30]; P = .17). The odds of failure were 68% higher with medial versus lateral repairs (P < .001). There was a significant relationship between baseline Marx activity level and the risk of subsequent meniscal repair failure; patients with either very low (0-1 points) or very high (15-16 points) baseline activity levels were at the highest risk (P = .004).

Conclusion

Meniscal repair location (medial vs lateral) and baseline activity level were the main drivers of meniscal repair outcomes. Graft type was ranked third, demonstrating that meniscal repairs performed with allograft were 2.3 times more likely to fail compared with BTB autograft. There was no significant difference in failure rates between BTB versus soft tissue autografts.

Registration

NCT00463099 (ClinicalTrials.gov identifier).

Bucket handle meniscus tears in low-resource settings can be successfully treated with a cost-effective technique

PURPOSE

In regions of the world where resources can limit medical care (limited-resource settings, LRS), most meniscal tears are often treated with meniscectomy. A simple, low-cost option for meniscal repair has been developed. We sought to evaluate patient reported outcomes (PROMs) and clinical failure rates of bucket handle meniscus tears (BHTs) treated with meniscal repair in a LRS.

METHODS

We prospectively enrolled patients over 18 who were treated for BHT with meniscal repair in a LRS. Meniscal repair was primarily accomplished using an outside-in technique. Pre-injury and final follow-up PROMs were recorded. Clinical failure was defined as the need for re-operation or symptoms that prevented the patient from returning to recreational activities or work responsibilities.

RESULTS

Nineteen patients with a mean age of 25.4 years were eligible. Two patients sustained a clinical failure (10.5%). At mean follow-up of 40.6 months, there was significant improvement in all PROMs from baseline. Subgroup analysis revealed no significant difference in the failure group compared to the success group in number of knots used, pre-injury Tegner score, number of devices used, suture type, or technique.

CONCLUSION

Bucket-handle meniscal tears can be repaired using a low-cost technique resulting in satisfactory healing rates and excellent outcomes.

Indirect Magnetic Resonance Arthrography May Help Avoid Second Look Arthroscopy for Assessment of Healing After Bucket Handle Medial Meniscus Repairs: A Prospective Clinico-Radiological Observational Study

OBJECTIVES

The objectives were: (1) to analyze the MRI healing rates of bucket-handle meniscus repair; (2) to compare the accuracy of assessment of meniscus healing for conventional MRI and Indirect Magnetic Resonance Arthrography (IMRA); and (3) to identify patients who may require second-look arthroscopy after meniscus repair.

METHODS

This is a prospective observational case series of thirty-seven patients with repaired bucket-handle medial meniscus tear with a minimum one year follow-up. Meniscus healing rates were assessed on direct MRI and IMRA using Henning's criteria. At the same time, patients' symptoms were evaluated according to Barrett's criteria and functional outcomes were recorded using International Knee Documentation Committee (IKDC) score, Knee Osteoarthritis and Outcomes Score (KOOS) and Tegner-Lysholm scores. A further clinical review was performed 18 months after the imaging to assess the evolution of symptoms.

RESULTS

At a mean of 22.3 ± 7.8 months after the meniscus repair, 56.7% patients showed complete healing and 40.5% patients demonstrated incomplete repair healing on IMRA. 52% patients with complete healing and 40% patients with incomplete healing demonstrated meniscus symptoms. At the second clinical review, 19% patients with complete healing and 20% patients with incomplete healing had meniscus symptoms. There was no co-relation between symptoms, PROMs and healing on MRI.

CONCLUSION

Indirect MR arthrography offers distinct advantages over direct MRI for assessment of meniscus healing, especially in symptomatic patients. Patient-reported outcome measures and symptomatology are not co-related with the healing status of the meniscus and they resolve in the majority on longer follow-up. A more conservative approach guided by IMRA to assess meniscus healing will avoid early re-operations.

Biologic Augmentation Reduces the Failure Rate of Meniscal Repair: A Systematic Review and Meta-analysis

Background

Clinical results after isolated meniscal repair are not always satisfactory, with an overall failure rate of around 25%. To improve the success rate of meniscal repair, different biologic augmentation techniques have been introduced in clinical practice, but their real efficacy is still controversial.

Purpose/Hypothesis

To evaluate the safety, clinical results, and failure rate of biologic augmentation techniques for meniscal repair. The hypothesis was that biologic augmentation would improve the results of meniscal repair.

Study Design

Systematic review and meta-analysis of comparative studies.

Methods

A systematic review of the literature was performed in March 2020 of 3 electronic databases (PubMed, Scopus, and the Cochrane Library) regarding meniscal repair combined with biologic augmentation techniques. Articles combining biologic augmentation with other surgical procedures besides meniscal suture were excluded. The quality of the included studies was assessed using a modified Coleman Methodology Score, and the risk of bias was evaluated using the ROBINS-I (Risk of Bias in Non-randomized Studies of Interventions) and the RoB 2.0 (Revised Tool for Risk of Bias in Randomized Trials) for nonrandomized and randomized controlled trials, respectively.

Results

A total of 11 studies were included in the qualitative analysis: platelet-rich plasma (PRP) augmentation in 6 comparatives studies, fibrin clot augmentation in 2 case series, and mesenchymal stem cells augmentation in 2 case series and 1 case report. One severe adverse event of septic arthritis was reported for PRP 1 month after surgery. The quality of evidence evaluated with the modified Coleman Methodology Score was low overall. Five studies reporting on 286 patients (111 PRP augmentation, 175 control) were included in the quantitative synthesis. A significantly lower risk of failure was documented in the PRP augmentation group as compared with the control group: 9.9% (4.5%-19.1%) versus 25.7% (12.7%-38.7%) (P < .0005).

Conclusion

The literature on biologic meniscal augmentation is recent and scarce. Only a few comparative trials are available, all focusing on the potential of PRP. The meta-analysis documented that PRP is safe and useful in improving the survival rate, with a 9.9% rate of failure versus 25.7% for the control group. Further high-level studies are needed to confirm these findings and identify the most effective biologic augmentation strategy to improve the outcome of meniscal repair.

Editorial Commentary: Moving the Needle: Traditional Inside-Out Meniscal Repair Has Advantages Over All-Inside Repair

Meniscus repairs for vertical, peripheral tears can be troublesome due to poor tissue quality and/or vascularity that can lead to re-rupture and subsequent removal. The gold standard, inside-out repair technique, has been challenged by all-inside devices for the benefit of improved efficiency and less morbidity but for the sake of expense and potential structural inferiority. Successful meniscus repair requires multiple components, only one of which is deciding the repair construct of choice. I feel the most important aspect will always be the indication based on tear configuration while respecting biology, because all fixation will eventually fail if the meniscus does not ultimately heal. While all-inside devices may have biomechanical properties that are similar to inside-out techniques, the burden of proof still lies on showing superiority of these devices in a clinical setting. Clinically, I still use inside-out repair techniques for large tears or for high-demand patients due to its structural integrity and small penetration of the meniscus.