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

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.

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.

Biologic Augmentation of Isolated Meniscal Repair

PURPOSE OF REVIEW

The limited blood supply and intrinsic healing capacity of the meniscus contributes to suboptimal tissue regeneration following injury and surgical repair. Biologic augmentation techniques have been utilized in combination with isolated meniscal repair to improve tissue regeneration. Several innovative strategies such as Platelet-Rich Plasma (PRP), fibrin clots, mesenchymal stem cells (MSCs), bone marrow stimulation, meniscal scaffolds, and meniscal wrapping, are being explored to enhance repair outcomes. This article provides a comprehensive review of recent findings and conclusions regarding biologic augmentation techniques.

RECENT FINDINGS

Studies on PRP reveal mixed outcomes, with some suggesting benefits in reducing failure rates of isolated meniscal repair, while others question its efficacy. Fibrin clots and PRF (Platelet-rich fibrin), although promising, show inconsistent results and lack sufficient evidence for definitive conclusions. MSCs demonstrate potential in preclinical studies, but clinical trials have been limited and inconclusive. Bone marrow stimulation appears effective in certain contexts, but its broader applicability remains uncertain. Meniscal scaffolds, including CMI (Collagen Meniscal Implants) and Actifit (polyurethane scaffolds), show encouraging short- and mid-term outcomes but have not consistently surpassed traditional methods in the long term. Meniscal wrapping is infrequently studied but demonstrates positive short-term results with certain applications. The review reveals a diverse range of outcomes for biologic augmentation in meniscal repair. While certain techniques show promise, particularly in specific scenarios, the overall efficacy of these methods has yet to reach a consensus. The review underscores the necessity for standardized, high-quality research to establish the definitive effectiveness of these biologic augmentation methods.

Usefulness of Probing Sensor Device for Evaluating Meniscal Suture and Scaffold Implantation

Appropriate suture tension is a key factor in successful meniscal repair. This study aimed to clarify the appropriate value of meniscal stabilization with suture repair based on a probing procedure for healthy porcine menisci and a novel meniscal scaffold. After evaluating the reliability of the probing sensor, meniscal vertical tear and partial meniscectomy models were developed, in which suture repair and meniscal scaffold implantation were performed at suture intervals ranging between 20 and 2.5 mm. The residence forces at each interval were evaluated using a probing sensor. Moreover, a tensile test was conducted to evaluate the displacement and presence or absence of gaps. We found that normal and meniscal scaffolds should be fixed within 5 mm of suture interval. The probing residence forces required were at least 1.0 N for vertical tears and 3.0 N for meniscal scaffolds. These findings may be taken into consideration to reduce suture failure following meniscal tear repair and stabilizing meniscal scaffold fixation.

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.

Utility of Platelet-Rich Plasma Therapy in the Management of Meniscus Injuries: A narrative review

Menisci are crucial for knee joint functions and meniscal tears are common injuries, especially in sports activities. Platelet-rich plasma (PRP), which enhances healing, has emerged as a promising additive treatment for meniscus injuries, utilizing the regenerative properties of platelets and growth factors for improved clinical outcomes. In studies with a follow-up period of less than one year, the use of platelet-rich plasma (PRP) therapy for meniscus injuries showed significant improvements in knee symptoms and daily activity. Patients experienced enhanced outcomes in terms of pain reduction and increased sports activity, with MRI scans indicating stable meniscus conditions after six months. Studies with a follow-up of more than one year, however, did not find significant differences between groups treated with PRP and groups not treated with PRP in terms of various outcome measures, including pain and knee function. The vascularization of the menisci is vital for their proper function, and insufficient blood supply can affect healing of meniscal injuries. PRP therapy is used to enhance meniscal healing by introducing growth factors and anti-inflammatory agents. PRP therapy may enable athletes with meniscal tears to return to sports more quickly and has less rehabilitation duration. While PRP seems promising as an alternative to failed treatment or as an adjunct to treatment in the short term, its long-term effectiveness remains inconclusive. Patient preferences, commitment to therapy rehabilitation, and cost should all be considered on an individual basis.

Current Practices for Rehabilitation After Meniscus Repair: A Survey of Members of the American Orthopaedic Society for Sports Medicine

Background

There is no consensus among sports medicine surgeons in North America on postoperative rehabilitation strategy after meniscus repair. Various meniscal tear types may necessitate a unique range of motion (ROM) and weightbearing rehabilitation protocol.

Purpose

To assess the current landscape of how sports medicine practitioners in the American Orthopedic Society for Sports Medicine (AOSSM) rehabilitate patients after the repair of varying meniscal tears.

Study Design

Cross-sectional study.

Methods

A survey was distributed to 2973 AOSSM members by email. Participants reviewed arthroscopic images and brief patient history from 6 deidentified cases of meniscus repair-in cases 1 to 3, the tears retained hoop integrity (more stable repair), and in cases 4 to 6, the tear patterns represented a loss of hoop integrity. Cases were shuffled before the presentation. For each case, providers were asked at what postoperative time point they would permit (1) partial weightbearing (PWB), (2) full weightbearing (FWB), (3) full ROM, and (4) ROM allowed immediately after surgery.

Results

In total, 451 surveys were completed (15.2% response). The times to PWB and FWB in cases 1 to 3 (median, 0 and 4 weeks, respectively) were significantly lower than those in cases 4 to 6 (median, 4 and 6 weeks, respectively) (P < .001). In tears with retained hoop integrity, the median time to PWB was immediately after surgery, whereas in tears without hoop integrity, the median time to PWB was at 4 weeks postoperatively. Similarly, the median time to FWB in each tear with retained hoop integrity was 4 weeks after surgery, while it was 6 weeks in each tear without hoop integrity. However, regardless of tear type, most providers (67.1%) allowed 0° to 90° of ROM immediately after surgery and allowed full ROM at 6 weeks. Most providers (83.3%) braced the knee after repair regardless of hoop integrity and utilized synovial rasping/trephination with notch microfracture-a much lower proportion of providers utilized biologic augmentation (9%).

Conclusion

Sports medicine practitioners in the AOSSM rehabilitated meniscal tears differently based on hoop integrity, with loss of hoop stresses triggering a more conservative approach. A majority braced and utilized in situ adjuncts for biological healing, while a minority added extrinsic biologics.

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.

Failure rate, return-to-sports and magnetic resonance imaging after meniscal repair: 119 patients with 7 years mean follow up

BACKGROUND

One of the most important factors to consider in relation to meniscal repair is the high failure rate reported in the existing literature.

AIM

To evaluate failure rates, return to sports (RTS) rate, clinical outcomes and magnetic resonance image (MRI) evaluation after meniscus suture repair for longitudinal tears at a minimum 2-year-follow-up.

METHODS

We conducted a retrospective review of meniscal repairs between January 2004 and December 2018. All patients treated for longitudinal tears associated or not with an anterior cruciate ligament reconstruction (ACL-R) were included. Meniscal ramp lesions, radial and root tears, associated with multiligament injuries, tibial fracture and meniscal allograft transplants were excluded. Surgical details and failure rate, defined as symptomatic patients who underwent a revision surgery, were analyzed. As isolated bucket handle tears (BHTs) were usually associated with higher failure rates, we compared BHTs and not BHTs associated or not with an ACL-R. Since 2014, the inside-out technique using cannulas and suture needles with 2-0 Tycron began to predominate. In addition, the number of stitches per repair was increased. In view of differences in surgical technique, we compared two different cohorts: before and after 2014. We recorded the RTS according to the level achieved and the time to RTS. Lysholm and IKDC scores were recorded. Patients were studied with x-rays and MRI as standard postoperative control.

RESULTS

One hundred and nineteen patients were included with a mean follow up of 7 years (SD: 4.08). Overall failure rate was 20.3% at a mean 20.1 mo. No statistically significant differences were found when comparing failure for medial and lateral meniscal repair (22.7% and 15.3%, P = 0.36), BHTs and not BHTs (26% and 17.6%, P = 0.27), isolated or associated with an ACL-R (22.9% and 18%, P = 0.47), or when comparing only BHTs associated with an ACL-R (23% and 27.7%, P = 0.9) or not. When comparing cohorts before and after 2014, we found a significant decrease in the overall failure rate from 26% to 11% (P < 0.03). Isolated lesions presented a decrease from 28% to 6.6% (P = 0.02), BHTs from 34% to 8% (P = 0.09) and those associated with an ACL-R from 25% to 10% (P = 0.09). Mean RTS time was 6.5 mo in isolated lesions and 8.64 mo when associated with an ACL-R. Overall, 56% of patients returned to the same sport activity level. Mean pre and postoperative Lysholm scores were 64 and 85 (P = 0.02), and IKDC 58 and 70 (P = 0.03). Out of 84 asymptomatic patients evaluated with MRI, 39% were classified as "not healed" and 61% as "healed".

CONCLUSION

Even though the overall failure rate of our series was 20.3%, we found a statistically significant decrease from 26% to 11%, not only for isolated lesions, but also for BHT's and those associated with an ACL-R when comparing our series in two different cohorts, most probably due to improvements in surgical technique.

Impact of Biologic Augmentation on Revision Surgery Rates After Meniscus Repair: A Matched-Cohort Analysis of 3420 Patients

Background

Platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) have gained popularity in recent years as biologic approaches to potentially augment healing after meniscus repair. There have been few studies comparing outcomes in patients undergoing meniscus repair with versus without biologic augmentation and, furthermore, little clarity on the role of biologic augmentation for meniscus repairs performed with concomitant anterior cruciate ligament reconstruction (ACLR).

Purpose

To determine the association of BMAC or PRP augmentation with revision surgery after both isolated meniscus repair and meniscus repair performed concomitantly with ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

The PearlDiver Mariner dataset was queried to identify all patients who underwent primary meniscus repair, both with and without concomitant ACLR, and who received ipsilateral BMAC or PRP at the time of surgery. Patients who underwent similar surgery but without BMAC or PRP augmentation were then identified and matched in a 5:1 ratio according to age, sex, body mass index, and various comorbidities to 3 separate BMAC/PRP augmentation groups: overall cohort (with and without ACLR), repair with concomitant ACLR, and isolated repair. The primary outcome was revision meniscus surgery (meniscectomy or revision meniscus repair).

Results

Overall, 3420 patients (570 with BMAC/PRP augmentation; 2850 matched controls without augmentation) were included. There were no significant differences in the reported demographics or comorbidities between any of the BMAC/PRP groups and their respective matched controls (P > .05 for all comparisons). There was no difference in revision rate between BMAC/PRP-augmented isolated meniscus repairs and matched controls (P = .235). Patients who underwent BMAC/PRP-augmented meniscus repair with concomitant ACLR experienced a significantly lower incidence of revision surgery compared with matched controls without BMAC/PRP augmentation (5.2% vs 7.9% respectively; odds ratio, 0.41; 95% CI, 0.27-0.63; P < .001), but the number of revisions was relatively small.

Conclusion

There was no association between BMAC or PRP augmentation and the incidence of revision surgery after isolated primary meniscus repair. There was a statistically significant decrease in the rate of revision meniscus surgery when BMAC or PRP was used to augment meniscus repairs in the setting of concurrent ACLR; however, the overall revision rates were small.

The Current Role of Biologics for Meniscus Injury and Treatment

PURPOSE OF REVIEW

There is little doubt that the consensus has changed to favor preservation of meniscal function where possible. Accordingly, the indications for meniscal repair strategies have been refocused on the long-term interest of knee joint health. The development and refinements in surgical technique have been complemented by biological augmentation strategies to address intrinsic challenges in healing capacity of meniscal tissue, with variable effects.

RECENT FINDINGS

A contemporary approach to meniscal healing includes adequate surgical fixation, meniscal and synovial tissue stimulation, and management of the intraarticular milieu. Overall, evidence supporting the use of autogenous or allogeneic cell sources remains limited. The use of FDA-approved medications to effect biologically favorable mechanisms during meniscal healing holds promise. Development and characterization of biologics continue to advance with translational research focused on specific growth factors, cell and tissue behaviors in meniscal healing, and joint homeostasis. Although significant strides have been made in laboratory and pre-clinical studies, translation to clinical application remains challenging. Finally, expert consensus and standardization of nomenclature related to orthobiologics for meniscal preservation will be important for the advancement of this field.

Meniscus treatment: biological augmentation strategies: a narrative review

Objective

An up-to-date description on the biological augmentation strategies for meniscal repair procedures was performed to highlight the main preclinical and clinical evidence available in the literature.

Background

Meniscal repair is a key surgical procedure to preserve as much meniscal tissue as possible to limit the development of knee osteoarthritis (OA). Unfortunately, the results of meniscal repair procedures are not always satisfactory, reporting an overall risk of failure of 25%, likely conditioned due to the poor vascularization of the meniscal tissue. For this reason, several biologic augmentation techniques have been developed to improve the meniscal healing process, ranging from mechanical stimulations to biological products.

Methods

A literature review was conducted on the main biological augmentation procedures combined to the meniscal repair process. A description of the rationale, surgical technique, and preclinical and clinical evidence was performed.

Conclusions

Mechanical stimulations and fibrin clot were the first techniques applied showing several limitations and not exciting results. Recently, platelet-rich plasma (PRP) augmentation to meniscal repair is slowly spreading in the clinical practice. Early evidence from comparative studies showed a significantly lower failure rate in patients treated with PRP augmentation compared with controls. Conversely, the current few and low-level data on mesenchymal stem/stromal cells (MSCs) for meniscal augmentation repair make this a promising but anecdotal topic. Further high-quality clinical studies are needed to support and guide the use of biological strategies for the augmentation of meniscus repair, PRP.

Platelet-rich plasma (PRP) augmentation does not result in more favourable outcomes in arthroscopic meniscal repair: a meta-analysis

Background

The efficacy and safety of platelet-rich plasma (PRP) augmentation for arthroscopic meniscal repair is controversial. This meta-analysis compared arthroscopic meniscal repair performed in isolation or augmented with PRP.

Methods

The present study was conducted according to PRISMA 2020 guidelines. Pubmed, Web of Science, Google Scholar and Embase were accessed in August 2021. All the clinical trials which compared arthroscopic meniscal repair performed in isolation or augmented with PRP were included.

Results

Eight hundred thirty-seven patients were included: 38% (318 of 837 patients) were women; the mean age of the patients was 35.6 (range, 20.8–64.3) years; the mean follow-up was 26.2 (range, 6–54) months. Similarity was found in analogue scale (VAS) (P = 0.5) and Lysholm (P = 0.9), and International Knee Documentation Committee (IKDC) scores (P = 0.9). Similarity was found in the rate of failure (P = 0.4) and rate of revision (P = 0.07).

Conclusion

The current published scientific evidence does not support PRP augmentation for arthroscopic meniscal repair.

The use of autologous platelet-rich fibrin matrix combined with meniscal repair in the treatment of parameniscal cyst: clinical results and cyst recurrence after 2-year of follow up

Purpose

Parameniscal cysts are associate with horizontal meniscal tears. Arthroscopic meniscal repair and the excision of the cyst by mini-open approach represent a valid treatment. However, the recurrence of cyst is still a current issue. Therefore, biological factors may be considered to promote the biological repair and avoid recurrence. The aim of the present study was to report the clinical results and the rate of recurrence of the cyst after minimum 2-year of follow up in a cohort of patients treated by meniscal repair and autologous platelet-rich fibrin matrix augment.

Methods

Patients with lateral parameniscal cyst undergoing arthroscopic meniscal repair and autologous platelet-rich fibrin matrix augment between 2016 and 2019 were retrospectively reviewed in March 2021. Inclusion criteria were absence of prior surgery on the affected knee with minimum 2-year of follow-up. Exclusion criteria were concomitant ligament lesions, rheumatic diseases and knee osteoarthritis. After reviewing the database, each selected patient was contacted and asked to participate in the study; at the follow-up evaluation all patient signed an informed consent. Tegner-Lysholm knee score, IKDC and NRS were collected before surgery and at follow-up.

Results

This study included 15 patients (8 male) with mean age of 32.8 years old. No recurrence of the cysts was observed. The Tegner-Lysholm knee score and IKDC subjective scores increased respectively from 41.3 ± 5.4 and 37.6 ± 5.1 at baseline to 92.3 ± 4.6 and 89.4 ± 2.6 at the final follow up. Concerning pain relief, the Numeric Pain Rating Scale (NRS) displayed a significant improvement reaching at the follow up a score of 1,3 ± 1.1 in comparison to 6.8 ± 0.9 at the baseline.

Conclusion

Surgical management of symptomatic lateral parameniscal cyst with cyst excision, autologous PRP membrane application and meniscus repair demonstrated excellent subjective clinical outcome with any cyst reoccurrence.

Level of evidence

III, retrospective cohort study.