FasT-Fix versus inside-out suture meniscal repair in the goat model

Animal models used in meniscal repair research from ex vivo to in vivo: A systematic review

This systematic review, registered with Prospero, aims to identify an optimal animal model for meniscus repair research, moving from ex vivo experimentation to in vivo studies. Data sources included PubMed, Medline, all Evidence-Based Medicine Reviews, Web of Science, and Embase searched in March 2023. Studies were screened using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Extracted data including animal model, type of experiment, type of tear, surgical techniques, and measured outcomes, were recorded, reviewed, and analyzed by four independent reviewers. The SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) Rob tool was used for critical appraisal and risk of bias assessment. Out of 11,719 studies, 72 manuscripts were included for data extraction and analysis; 41 ex vivo extra-articular studies, 20 ex vivo intra-articular studies, and only 11 in vivo studies. Six animal models were employed: porcine, bovine, lapine, caprine, canine, and ovine. Longitudinal lesions were the most frequently studied tear pattern and sutures the most common repair technique. Studied outcomes focused mainly on biomechanical assessments and gross observations. This systematic review can guide researchers in their choice of animal model for meniscus repair research; it highlighted the strengths of the porcine, caprine, and bovine models for ex vivo cadaveric studies, while the porcine and caprine models were found to be more suited to in vivo studies due to their similarities with human anatomy. Research teams should familiarize themselves with the advantages and disadvantages of various animal models before initiating protocols to improve standardization in the field.

Effect of Microfracture on Meniscal Tear Healing in a Goat (Capra hircus) Model

Meniscal injuries are an extremely common cause of knee pain. Meniscal repairs performed with concomitant anterior cruciate ligament reconstruction appear to heal at a higher rate than meniscal repairs performed in isolation. This may be due in part to the release of marrow elements into the knee and the time of meniscal repair. In cases of isolated meniscal repair, some orthopedic surgeons use microfracture to release marrow elements into the joint as an adjunct to enhance meniscal healing. This study evaluated rates of meniscal tear healing with or without the performance of microfracture in a goat (Capra hircus) model. Forty castrated young adult male goats underwent either a horizontal or a longitudinal 1.0-cm meniscal tear with or without microfracture. All procedures were performed open, in a bloodless field. Meniscal tears were created in the peripheral half of the body of the medial meniscus. The goats were euthanized at 6 months, and meniscal tears were analyzed and classified as complete healing, partial healing, or no healing by direct visualization. A probe was used as an aid to evaluate and classify the meniscal tears. Twenty (87%) of 23 goat meniscal tears showed at least partial healing when performed with concomitant microfracture. Only 5 (29%) of 17 menisci showed any healing in goats that did not receive microfracture. This difference in healing rates was statistically significant (P<.001). Fifteen (65%) meniscal tears accomplished with microfracture were completely healed, whereas only 2 (12%) menisci showed complete healing without microfracture (P<.001). The results of this study suggest that the release of bone marrow elements into the knee by microfracture improves meniscal healing rates.

Animal models for meniscus repair and regeneration

The meniscus plays an important role in knee function and mechanics. Meniscal lesions, however, are common phenomena and this tissue is not able to achieve spontaneous successful repair, particularly in the inner avascular zone. Several animal models have been studied and proposed for testing different reparative approaches, as well as for studying regenerative methods aiming to restore the original shape and function of this structure. This review summarizes the gross anatomy, function, ultrastructure and biochemical composition of the knee meniscus in several animal models in comparison with the human meniscus. The relevance of the models is discussed from the point of view of basic research as well as of clinical translation for meniscal repair, substitution and regeneration. Finally, the advantages and disadvantages of each model for various research directions are critically discussed.

Stem cell-based tissue-engineering for treatment of meniscal tears in the avascular zone

Meniscal tears in the avascular zone have a poor self-healing potential, however partial meniscectomy predisposes the knee for early osteoarthritis. Tissue engineering with mesenchymal stem cells and a hyaluronan collagen based scaffold is a promising approach to repair meniscal tears in the avascular zone. 4 mm longitudinal meniscal tears in the avascular zone of lateral menisci of New Zealand White Rabbits were performed. The defect was left empty, sutured with a 5-0 suture or filled with a hyaluronan/collagen composite matrix without cells, with platelet rich plasma or with autologous mesenchymal stem cells. Matrices with stem cells were in part precultured in chondrogenic medium for 14 days prior to the implantation. Menisci were harvested at 6 and 12 weeks. The developed repair tissue was analyzed macroscopically, histologically and biomechanically. Untreated defects, defects treated with suture alone, with cell-free or with platelet rich plasma seeded implants showed a muted fibrous healing response. The implantation of stem cell-matrix constructs initiated fibrocartilage-like repair tissue, with better integration and biomechanical properties in the precultured stem cell-matrix group. A hyaluronan-collagen based composite scaffold seeded with mesenchymal stem cells is more effective in the repair avascular meniscal tear with stable meniscus-like tissue and to restore the native meniscus.

Determination of the safe penetration depth during all-inside meniscal repair of the posterior part of the lateral meniscus using the FasT-Fix suture repair system

PURPOSE

The objective of this study was to determine the safe penetration depth of the FasT-Fix meniscal suture repair system during all-inside repair of the posterior part of the lateral meniscus.

METHODS

Thirty-one knees from 17 embalmed and formalin-fixed cadavers (11 women, 6 men) were used. In each case, the circumference of the cadaver knee was measured before dissection. After dissection, 41 Fast-Fix meniscal repair devices were used in different predetermined penetration depths ranging from 8 to 16 mm. In this study, non-involvement of the popliteal neurovascular bundle, common peroneal nerve or the inferior lateral genicular vessels by either needle penetration or affixment by the suture bar anchors was considered to be a safe trial.

RESULTS

Out of the 41 FasT-Fix devices used in this study, only one device bent during introduction and was excluded from the study. For the remaining 40 trials, 27 of them were considered safe, while 13 trials were considered unsafe. The ratio of the average penetration depth to the average circumference of the cadaver knee was found to be >0.05 for the unsafe penetrations, and this was statistically significant P < 0.05. Additionally, for the first point, which is more central, there was a trend for the straight needles through the direct lateral approach to be less safe, and this was found to be statistically significant P < 0.05.

CONCLUSIONS

Correlating the needle-penetration depth to the measured circumference of the cadaver knee may be an important clinical predictor of safety whereby a ratio of less than 0.05 might be useful as a guide to determine the safe penetration depth of the FasT-Fix suture repair needle during repair of the posterior horn lateral meniscus. Also, it is better to avoid using straight needles through the direct lateral approach during repair of the more central portion of the posterior horn lateral meniscus.

Meniscal repair in anterior cruciate ligament reconstruction: a long-term outcome study

PURPOSE

To study the long-term outcome of patients who have undergone inside-out, vertical stacked mattress suture repair of meniscal tears combined with anterior cruciate ligament (ACL) reconstruction.

METHODS

From a database of ACL reconstructed patients, consecutive patients undergoing concomitant meniscal repair and ACL reconstruction between 1991 and 1999 were identified. Patients with previous ACL or meniscal pathology were excluded. Two age- and sex-matched cohorts who had undergone combined ACL reconstruction and menisectomy and who had undergone ACL reconstruction with normal menisci were identified for comparison. Outcome scoring included IKDC and Lysholm scores for the meniscal repair group. Two sample t-tests and chi-square tests were used to compare the IKDC subjective scores, with a minimum level of significance set at 5% (P = 0.05).

RESULTS

Fourty-four patients were identified for analysis with a median follow-up of 10 years (7.7-12.6). Patients undergoing ACL reconstruction combined with meniscal repair had a mean IKDC of 84.2 compared with a mean score of 70.5 (P = 0.008) in patients who had undergone menisectomy and 88.2 (P = 0.005) in patients with intact menisci. 86.2% of patients with ACL reconstruction and meniscal repair had Lysholm score of between 80 and 100%. Sixty-nine percent follow-up was achieved. Survival analysis by life table method shows a best case of 89% 10-years survival.

CONCLUSIONS

This study demonstrates that good long-term outcomes can be obtained in patients up to over 12 years after combined ACL reconstruction and meniscal repair. Improved functional scores can be achieved when compared with ACL reconstruction and menisectomy. The authors advocate repair of meniscal tears during ACL reconstruction unless there is complex tearing, radial tearing or plastic deformation of the remaining meniscus.

LEVEL OF EVIDENCE

III.

Neurovascular safety and clinical outcome of outside-in repair of tears of the posterior horn of the medial meniscus

PURPOSE

The purpose of this study was to evaluate the safety and clinical outcome of a new posterior approach for the known outside-in technique for repair of tears of the posterior horn of the medial meniscus (PHMM).

METHODS

First, a cadaveric study was performed on 6 cadaveric knees to assess the safety of a point just lateral to the semitendinosus tendon as an entry point for outside-in repair. Dissection was done to measure the clearance of this point to the nearby popliteal bundle and saphenous nerve. A prospective case series study was then performed to assess the clinical outcome of such an approach. We treated 41 consecutive cases with PHMM tears by the outside-in technique using a shuttle relay method through the same point. Clinical assessments, magnetic resonance imaging findings, Lysholm scores, and International Knee Documentation Committee subjective scores were recorded for all patients. After a minimum postoperative period of 2 years, all cases were re-evaluated and re-scored.

RESULTS

The cadaveric study showed a mean clearance distance of 2.4 cm for the popliteal bundle and 4.6 cm for the saphenous nerve. The case series study was done on 41 meniscal repairs; 15 of 41 cases (37%) were performed in conjunction with anterior cruciate ligament reconstruction. There were 22 right knees (54%) and 19 left knees (36%). After a mean follow-up period of 27 months, patients showed a clinical success rate of 88% in terms of disappearance of pain, locking, and swelling, together with improved Lysholm scores (from 34 to 88) and International Knee Documentation Committee scores (from 25 to 88). These improvements were statistically significant (P < .05).

CONCLUSIONS

An outside-in repair technique with a posterior entry central to the semitendinosus tendon was used safely with 88% satisfactory clinical results for treatment of PHMM tears.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Repair integrity evaluated by second-look arthroscopy after arthroscopic meniscal repair with the FasT-Fix during anterior cruciate ligament reconstruction

BACKGROUND

Although several devices for meniscal repairs have become available, a successful outcome is ultimately due to a healed meniscus on the clinical findings. The authors assessed the repair integrity after meniscal repair with the FasT-Fix device using second-look arthroscopy.

HYPOTHESIS

Meniscal repair with the FasT-Fix will lead to arthroscopically evident healing, but some menisci will show incomplete healing even in clinically successful cases and have newly formed injuries on the meniscal substance resulting from the path of the implant.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Sixty-five consecutive patients were studied, in whom 84 menisci were subjected to all-inside meniscal repair with the FasT-Fix device in conjunction with anterior cruciate ligament reconstruction. Repair was only performed on longitudinal or double longitudinal tears within the red-red or red-white zone. The repaired menisci were evaluated by second-look arthroscopy at the time of staged hardware removal after anterior cruciate ligament reconstruction.

RESULTS

Sixty-two meniscal tears in 46 patients were available for this study. Eight patients were found to be symptomatic and considered to be clinical failures. The clinical success rate was 83%. At second-look arthroscopy, 46 tears (74%) were healed, 9 (15%) were healed incompletely, and 7 (11%) had failed. In the failed menisci, 1 had meniscal symptoms, while the other 6 were asymptomatic. In the 9 menisci with incomplete healing, 3 were associated with nonspecific knee pain but none showed meniscal symptoms. Newly formed injuries, which occurred in an area different from the original repair site, were confirmed on the surface of 19 menisci (35%) among the healed and incompletely healed menisci. Thirty menisci (48%) displayed successful and complete healing of the original tear site without newly formed tears.

CONCLUSION

Meniscal repair with the FasT-Fix in conjunction with anterior cruciate ligament reconstruction resulted in complete healing in 74% of cases. Eighty-three percent of menisci were symptom-free regardless of meniscal integrity. Even when the menisci repaired are asymptomatic and considered to be a clinical success, however, there may be newly formed injuries.

2009 survey results: surgeon practice patterns regarding arthroscopic surgery

A survey was conducted to collect information on the surgical management and practice preferences of the audience members at a recent continuing medical education conference. Participants were polled on a variety of surgical topics, and their responses were recorded using a wireless audience response system. The answers were tabulated and are presented in this report. The majority of respondents preferred an arthroscopic repair for rotator cuff tears (52%) and shoulder instability (71%). Most (50%) perform single-row repair; 33% perform double-row repair. For simple knee arthroscopy, most use preoperative antibiotics (85%), no tourniquet (53%), and no chemical anticoagulation or only compression boots (69%). For cruciate ligament reconstruction, the majority preferred only a preoperative antibiotic (67%), no chemical anticoagulation or only compression boots (56%), and single-bundle reconstruction (88%) using a transtibial femoral tunnel (78%). Most (47%) prefer an all inside suture-based meniscus repair device.