A new rigid biodegradable anchor for meniscus refixation: biomechanical evaluation

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.

Efficacy of meniscus suture absorbability on meniscus healing success rate via second-look arthroscopy after meniscal repair: a systematic review and meta-analysis

BACKGROUND

To preserve the meniscus's function, repairing the torn meniscus has become a common understanding. After which, the search for the ideal suture material is continuous. However, it is still controversial about the efficacy of suture absorbability on meniscus healing.

METHODS

This review is designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

INCLUSION CRITERIA

(1) Studies on meniscus repair; (2) Second-look arthroscopy was performed; (3) The meniscus was repaired by absorbable and non-absorbable sutures; (4) The healing condition of repaired meniscus via second-look arthroscopy was described.

EXCLUSION CRITERIA

(1) Animal studies, cadaveric studies, or in vitro research; (2) Meniscus transplantation; (3) Open meniscus repair; (4) Reviews, meta-analysis, case reports, letters, and comments; (5) non-English studies. MEDLINE, Embase, and Cochrane Database were searched up to October 2022. Risk of bias and methodology quality of included literature were assessed according to ROBINS-I and the modified Coleman Methodological Scale (MCMS). Descriptive analysis was performed, and meta-analysis was completed by RevMan5.4.1.

RESULTS

Four studies were included in the systematic review. Among them, three studies were brought into the meta-analysis, including 1 cohort study and 2 case series studies about 130 patients with meniscal tears combined with anterior cruciate ligament injury. Forty-two cases were repaired by absorbable sutures, and 88 were repaired by non-absorbable sutures. Using the fixed effect model, there was a statistical difference in the healing success rate between the absorbable and the non-absorbable groups [RR1.20, 95%CI (1.03, 1.40)].

CONCLUSION

In early and limited studies, insufficient evidence supports that non-absorbable sutures in meniscus repair surgery could improve meniscal healing success rate under second-look arthroscopy compared with absorbable sutures. In contrast, available data suggest that absorbable sutures have an advantage in meniscal healing.

TRIAL REGISTRATION

The review was registered in the PROSPERO System Review International Pre-Registration System (Registration number CRD42021283739).

Increased Construct Stiffness With Meniscal Repair Sutures and Devices Increases the Risk of Cheese-Wiring During Biomechanical Load-to-Failure Testing

Background:

Cheese-wiring, the suture that cuts through the meniscus, is a well-known issue in meniscal repair. So far, contributing factors are neither fully understood nor sufficiently studied.

Hypothesis/Purpose:

To investigate whether the construct stiffness of repair sutures and devices correlates with suture cut-through (cheese-wiring) during load-to-failure testing.

Study Design:

Controlled laboratory study.

Methods:

In 131 porcine menisci, longitudinal bucket-handle tears were repaired using either inside-out sutures (n = 66; No. 0 Ultrabraid, 2-0 Orthocord, 2-0 FiberWire, and 2-0 Ethibond) or all-inside devices (n = 65; FastFix360, Omnispan, and Meniscal Cinch). After cyclic loading, load-to-failure testing was performed. The mode of failure and construct stiffness were recorded. A receiver operating characteristic curve analysis was performed to define the optimal stiffness threshold for predicting meniscal repair failure by cheese-wiring. The 2-tailed t test and analysis of variance were used to test significance.

Results:

Loss of suture fixation was the most common mode of failure in all specimens (58%), except for the Omnispan, which failed most commonly because of anchor pull-through. The Omnispan demonstrated the highest construct stiffness (30.8 ± 3.5 N/mm), whereas the Meniscal Cinch (18.0 ± 8.8 N/mm) and Ethibond (19.4 ± 7.8 N/mm) demonstrated the lowest construct stiffness. The Omnispan showed significantly higher stiffness compared with the Meniscal Cinch (P < .001) and Ethibond (P = .02), whereas the stiffness of the Meniscal Cinch was significantly lower compared with that of the FiberWire (P = .01), Ultrabraid (P = .04), and FastFix360 (P = .03). While meniscal repair with a high construct stiffness more often failed by cheese-wiring, meniscal repair with a lower stiffness failed by loss of suture fixation, knot slippage, or anchor pull-through. Meniscal repair with a stiffness >26.5 N/mm had a 3.6 times higher risk of failure due to cheese-wiring during load-to-failure testing (95% CI, 1.4-8.2; P < .0001).

Conclusion:

Meniscal repair using inside-out sutures and all-inside devices with a higher construct stiffness (>26.5 N/mm) was more likely to fail through suture cut-through (cheese-wiring) than that with a lower stiffness (≤26.5 N/mm).

Clinical Relevance:

This is the first study investigating the impact of construct stiffness on meniscal repair failure by suture cut-through (cheese-wiring).

Biomechanical comparison of vertical suture techniques for repairing radial meniscus tear

Purpose

The aim of this study was to (1) develop suture techniques in repairing radial meniscal tear; (2) to compare the biomechanical properties of the proposed repair techniques with the conventional double horizontal technique.

Methods

Thirty-six fresh-frozen porcine medial menisci were randomly assigned into four groups and a complete tear was made at the midline of each meniscus. The menisci were subsequently repaired using four different repair techniques: double vertical (DV), double vertical cross (DVX), hybrid composing one vertical and one horizontal stitch, and conventional double horizontal (DH) suture technique with suturing parallel to the tibia plateau. The conventional double horizontal group was the control. The repaired menisci were subjected to cyclic loading followed by the load to failure testing. Gap formation and strength were measured, stiffness was calculated, and mode of failure was recorded.

Results

Group differences in gap formation were not statistically significant at 100 cycles (p = .42), 300 cycles (p = .68), and 500 cycles (p = .70). A trend was found toward higher load to failure in DVX (276.8 N, p < .001), DV (241.5 N, p < .001), and Hybrid (237.6 N, p < .001) compared with DH (148.5 N). Stiffness was also higher in DVX (60.7 N/mm, p < .001), DV (55.3 N/mm, p < .01), and Hybrid (52.1 N/mm, p < .01), than DH group (30.5 N/mm). Tissue failure was the only failure mode observed in all specimens.

Conclusion

Our two proposed vertical suture techniques, as well as the double vertical technique, had superior biomechanical properties than the conventional technique as demonstrated by higher stiffness and higher strength.

Meta-analysis on biomechanical properties of meniscus repairs: are devices better than sutures?

PURPOSE

Meniscal repair devices have been extensively tested during the past decades as reported in the literature. Reviewing the different meniscal repair devices and sutures with their respective biomechanical properties.

METHODS

For this meta-analysis, we conducted a systematic online search using PubMed, EMBASE, CCTR, and CINAHL using the search terms Meniscus OR Meniscal AND Biomechanics AND Repair). Load-to-failure (LtF), stiffness, and cyclic outcome measures were extracted independently and in duplicate. The systematic search revealed 841 manuscripts in total. After exclusion of duplicates and irrelevant publications, 41 studies remained for final analysis. The studies were published in English and German from 1995 to 2013. Due to differing cyclic force protocols, cyclic outcomes had to be excluded.

RESULTS

Overall, sutures had a higher LtF [suture: 87.7 ± 0.3 N (weighted mean ± standard error), device: 56.3 ± 0.1 N] and stiffness (suture: 8.9 ± 0.04 N/mm, device: 8.6 ± 0.04 N/mm) than devices, both p < 0.05. In LfT testing, PDS 0 Vertical (145.0 ± 8.1 N), OrthoCord 2-0 (143.6 ± 11.3 N), and Ethibond No 0 Vertical (133.4 ± 7.7 N) were the strongest sutures and Meniscal Viper (140.9 ± 5.1 N), MaxFire Vertical (136.2 ± 11.3 N), and FasT-Fix Vertical (115.2 ± 1.6 N) were the strongest devices. Second-generation devices were significantly stronger and stiffer than first-generation devices (p < 0.001).

CLINICAL RELEVANCE

Suture repair remains the gold standard with a vertically oriented suture configuration showing superior LtF values compared to a horizontal configuration. Nevertheless, some meniscal repair devices have similar biomechanical properties to suture repairs. Both suture repairs and devices have a place in meniscal restoration.

LEVEL OF EVIDENCE

None, meta-analysis of controlled laboratory studies.

Repair of peripheral vertical meniscus lesions in porcine menisci: in vitro biomechanical testing of 3 different meniscus repair devices

BACKGROUND

All-inside meniscus repair eliminates the need for an extra incision and decreases neurovascular injury risk. Biomechanical testing can help delineate the efficacy of all-inside device use.

HYPOTHESIS

There would be no group differences between 4 peripheral meniscus repair techniques and 3 different devices tested.

STUDY DESIGN

Controlled laboratory study.

METHODS

Equivalent-sized menisci with attached tibiae were randomly assigned to 1 of 4 test groups (8 specimens each), as follows: group 1, Fast-Fix using No. 0 braided polyester suture; group 2, inside-out repair using 2-0 braided polyester suture; group 3, Sequent using No. 0 ultra-high molecular weight polyethylene (UHMWPE) suture in a continuous "N" configuration; and group 4, Sequent using No. 0 UHMWPE suture in an interrupted configuration. After placement in a clamp, specimens underwent preconditioning from 5 to 20 N for 10 cycles (0.1 Hz), 500 submaximal loading cycles from 5 to 20 N (0.5 Hz), and load-to-failure testing at 12.5 mm/s. A 30-second pause after 10 preconditioning cycles and after 10, 100, and 500 submaximal loading cycles enabled digital photographs to be taken for gapping measurements. Failure mode was recorded.

RESULTS

Specimens in group 3 withstood greater failure loads than did those in groups 1 and 4 (P ≤ .027), and group 3 specimens were stiffer than those in groups 2 and 4 (P ≤ .048). Displacement during submaximal loading and load-to-failure testing did not differ between groups. Groups 1, 3, and 4 each gapped less than group 2 during submaximal cyclic loading (P ≤ .05). Groups 1 and 2 failed primarily by suture breakage (P < .0001), while groups 3 and 4 failed primarily by the suture pulling free from an implant (P < .0001).

CONCLUSION

Sequent using No. 0 UHMWPE suture in a continuous "N" configuration displayed superior load at failure compared with repairs using Fast-Fix with No. 0 braided polyester suture and displayed greater stiffness and less gapping than inside-out repair using 2-0 braided polyester suture. The suture pulling free from an implant was the primary failure mode for Sequent using No. 0 UHMWPE suture regardless of whether a continuous "N" or an interrupted configuration was used. Study groups that used No. 0 UHMWPE sutures (groups 3 and 4) had more specimens fail by the suture pulling free from an implant. Compared with the weaker braided polyester suture in the inside-out and Fast-Fix groups, the No. 0 UHMWPE suture used in the Sequent groups likely influenced study results, as this suture has stronger material properties. However, the continuous "N" configuration likely also improved the performance of the Sequent with No. 0 UHMWPE suture, as failure load was significantly less with an interrupted configuration.

CLINICAL RELEVANCE

All-inside meniscus repair with continuous suture function may translate into improved patient outcomes.

Cyclic test comparison of all-inside device and inside-out sutures for radial meniscus lesion repair: an in vitro porcine model study

PURPOSE

To compare biomechanical fixation and gapping characteristics of a new all-inside meniscus repair method for radial meniscus lesion repair versus conventional inside-out suture repair under submaximal cyclic loading and load-to-failure test conditions.

METHODS

Fresh-frozen porcine tibiae with attached lateral menisci and joint capsules were harvested and stored for 48 hours at -20°C. After thawing for 12 hours, equivalent-size healthy specimens were randomly assigned to 2 groups of 8 specimens each. Standardized radial lesions were repaired with the Sequent device (ConMed Linvatec, Largo, FL) (group 1) or conventional inside-out suturing with No. 2-0 braided polyester suture (group 2). Repaired specimens were placed in custom clamps and mounted on a servohydraulic device. After a 2-N preload, specimens were cycled from 5 to 20 N (0.1 Hz), before undergoing 1,000 submaximal loading cycles between 5 and 20 N (0.5 Hz). A 40-second delay at 100, 500, and 1,000 cycles enabled digital photographs to be taken for gapping measurement determination. Specimens then underwent load-to-failure testing (12.5 mm/s). Fixation failure mode was documented.

RESULTS

Group displacement did not differ after 1, 100, 500, and 1,000 submaximal loading cycles. Group peak gapping did not differ at 100, 500, and 1,000 submaximal loading cycles. Load at failure and displacement and stiffness during load-to-failure testing did not differ between groups. During load-to-failure testing, all-inside specimens failed by implant dislodgement from the meniscus periphery whereas the inside-out repaired specimens failed by suture rupture.

CONCLUSIONS

Under controlled in vitro biomechanical test conditions, the all-inside device provided radial meniscus lesion fixation that was comparable, but not superior, to conventional inside-out suturing.

CLINICAL RELEVANCE

The all-inside radial lateral meniscus lesion repair method may provide comparable fixation to conventional inside-out suturing without the need for additional incisions and their associated neurovascular injury risks.

Strategies for repair of radial tears close to the meniscal rim--biomechanical analysis with a cyclic loading protocol

BACKGROUND

Lateral meniscectomy contributes to early-onset osteoarthritis. Biomechanical properties of sutures repairs for complete radial meniscal tears remain unknown.

HYPOTHESIS

Double horizontal suture techniques for repair of radial meniscal tears with a shorter distance from the meniscal rim provide significantly higher structural properties than do comparable single-suture techniques with a wider distance from the meniscal rim.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 55 fresh-frozen porcine menisci, standardized complete radial meniscal tears were repaired with different distances from the meniscal rim and tear edges and with different numbers of sutures. In group A, the suture was 4 mm from the tear and 8 mm from the meniscal rim; group B, 2 mm from tear; group C, 2 mm from tear, 12 mm from rim; group D, double-loop technique, 2 mm from tear, 5 mm and 10 mm from rim; group E, longitudinal tear sutured with 1 loop, 8 mm from rim, and 4 mm between stitches. The specimens were cyclically loaded 1000 times between 5 and 20 N and loaded to failure.

RESULTS

All repaired constructs survived the cyclic loading protocol. Compared with the single-loop techniques, the double-loop technique (group D) showed a significantly higher maximum load and yield load and significantly lower displacement after 1000 cycles. Compared with group B, group C had a higher displacement after 1000 cycles (P < .05), and its stiffness showed a descriptive negative trend (P = .09). Displacement after cycling testing in group C was higher than in groups B and D (P < .05).

CONCLUSION

Repair of radial meniscal tears with a second suture and shorter distance from the meniscal rim has a positive influence on primary stability. Different distances from tear edges apparently have no influence on structural properties.

CLINICAL RELEVANCE

Horizontal sutures for repair of radial meniscal tears provide high stability and can be enhanced with a second horizontal suture and shorter distance from the meniscal rim.

Mechanical comparison of meniscal repair devices with mattress suture devices in vitro

We report the load to failure in tensile testing of the MaxFire™ meniscal repair system (Biomet Inc, Warsaw, IN) and compare it to other current meniscal repair devices and mattress suture techniques. After creating a longitudinal tear in 42 one-year-old bovine menisci, 7 specimen groups defined by the meniscal repair device, suture, and/or mattress technique used for meniscal repair were randomly established: (Group 1: Fiberwire™ vertical mattress (VM), Group 2: Fiberwire™ horizontal mattress (HM), Group 3: FasT-Fix™ VM, Group 4: FasT-Fix™ HM, Group 5: RapidLoc™, Group 6: MaxFire™ VM, Group 7: MaxFire™ HM). After completing the repairs, the meniscal specimens were cyclically pre-loaded before load to failure testing was performed. The mean load to failure for each group was: Fiberwire VM (185 ± 41 N), Fiberwire HM (183 ± 36 N), FasT-Fix VM (125 ± 8 N), FasT-Fix HM (107 ± 29 N), RapidLoc (70 ± 12 N), MaxFire VM (145 ± 44 N), MaxFire HM (139 ± 50 N). An analysis of variance demonstrated a significant difference in the mean load to failure (F = 8.31 P < 0.01). Statistically significant differences were seen between both Fiberwire groups verses FasT-Fix HM and Rapid-Loc (P < 0.05). Three modes of failure were observed: suture breakage (17/42, 40.5%), tissue failure (18/42, 42.9%), and knot failure (7/42, 16.7%). 2-0 Fiberwire™ VM and HM repairs had the highest load to failure of all groups tested. The load to failure for the MaxFire™ meniscal repair system is comparable to other available all-inside meniscal repair systems.

Tensile and shear loading stability of all-inside meniscal repairs: an in vitro biomechanical evaluation

BACKGROUND

Most biomechanical studies for evaluation of the structural properties of meniscal repairs have been performed in tensile loading scenarios perpendicular to the circumferential meniscal fibers. However, meniscal repair constructs are also exposed to shear forces parallel to the circumferential meniscal fibers during healing, particularly in the midportion of the meniscus.

HYPOTHESIS

Material properties of meniscal repair devices cannot be extrapolated from tensile to shear load scenarios.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 84 harvested and isolated bovine lateral menisci following removal of adjacent soft tissue, a standardized vertical lesion was set followed by repair using all-inside flexible (FasT-Fix, FasT-Fix AB, RapidLoc) and rigid (Meniscus Screw, Meniscus Arrow) meniscal repair devices. Vertical and horizontal 2.0 Ethibond sutures were used as controls. The repaired meniscal construct was tested in a tensile (parallel to the axis of the tested repair device) and shear load scenario (perpendicular to the axis of the tested repair device) at 5 mm/min and 37 degrees C environmental temperature. Maximum load to failure, stiffness, and failure mode were recorded.

RESULTS

The absolute load to failure values of each repair device in the shear scenario were only marginally different from the tensile load scenario. However, the stiffness of several tested devices was markedly reduced in the shear scenario. In both scenarios, large differences of the load to failure and the stiffness between the implant types up to 5-fold were found (P < .05). The failure mode of several all-inside flexible repair devices was different in the shear versus tensile load scenario, while the failure mode of the rigid systems was similar in both scenarios.

CONCLUSION

All-inside meniscal repair devices exposed to shear load scenarios have comparable maximum loads to failures as tensile load scenarios. However, the stiffness of the majority of the flexible meniscal repair implants in a shear load scenario is markedly reduced. The applied scenario also affects the failure mode in several flexible meniscal repair devices.

CLINICAL RELEVANCE

Meniscal repair devices with sufficient stiffness and stability against shear loads may be favored for meniscal repair, especially within the midportion of the meniscus where shear loads occur during healing.

[Complications with all-inside devices used in reconstructive meniscal surgery]

All-inside devices have become increasingly popular in reconstructive meniscal surgery since their introduction at the beginning of the 1990s. Although the latest clinical investigations show better results for conventional suture techniques, meniscal devices are an important alternative because of the low risk of neurovascular injury and the easy handling of the instruments. Over the years, many reports on specific complications related to all-inside devices have been published. Especially chondral injuries, implant loosening, device migration and capsular or neural irritations have been described. Furthermore, some authors reported on foreign body reactions and cystic granulomas after the use of meniscal fixation devices. However, there is no evidence for a higher infection rate or for specific infections after the use of intra-articular techniques. Clinical reports on complications along with biomechanical studies on meniscal repair devices have led to the enhancement of all-inside techniques through substantial modifications of established products as well as to the development of new implants. After reviewing the latest literature, the complication rate seems to be decreasing. In many ways, all-inside devices are an interesting alternative to conventional suture techniques. A precise knowledge of their potential complications and the pitfalls during surgery however is crucial to make a risk evaluation in the choice of the right technique for meniscal reconstruction.

Fixation properties of a biodegradable "free-form" osteosynthesis plate with screws with cut-off screw heads: biomechanical evaluation over 26 weeks

OBJECTIVE

The aim of this study was to compare the postoperative fixation properties of a biodegradable osteosynthesis "free-form" plate achieved with countersunk screws with those provided by screws with cut-off screw heads.

STUDY DESIGN

Acrylic pipes were fixed together to simulate fracture fixation for tensile testing. Additional plates were fixed to a polyurethane block with a single screw for plate-screw pullout testing. Specimens were incubated in phosphate buffer solution at 37 degrees C, and testing was conducted at various time points during hydrolytic degradation of 26 weeks. In both tests the specimens were loaded at a speed of 5 mm/min until failure. The yield load, maximum load, and stiffness were recorded, and failure mode was visually determined.

RESULTS

Both countersunk screws and screws with cut-off screw heads provided similar plate fixation properties over degradation time.

CONCLUSION

According to these results, fixation of the biodegradable osteosynthesis free-form plate with screws with cut-off screw heads seems to be feasible.

Elongation and structural properties of meniscal repair using suture techniques in distraction and shear force scenarios: biomechanical evaluation using a cyclic loading protocol

BACKGROUND

Most biomechanical studies on meniscal repairs have focused on testing distraction scenarios to evaluate structural properties of the repaired meniscus. An application of shear forces might replicate the in vivo situation more closely.

HYPOTHESIS

In the shear force scenario, meniscal repair using a vertical suture technique will result in significantly less elongation when subjected to a cyclic loading protocol than that resulting from a horizontal suture technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

In fresh-frozen porcine menisci (n = 10 in each group), horizontal and vertical 2.0 Ethibond suturing techniques were tested in distraction and shear force scenarios. Elongation after 1000 cycles between 5 and 20 N and the structural properties such as stiffness, yield load, maximum load to failure, and failure mode were evaluated using a testing machine at a rate of 12.5 mm/s.

RESULTS

In the distraction force scenario, no statistically significant difference in elongation after cyclic loading was found between specimens repaired with vertical or horizontal suture techniques. After 1000 cycles of cyclic loading in the shear force scenario, the horizontal suturing revealed significantly less elongation (2.8 +/- 1.1 mm) than did the vertical suture technique (4.6 +/- 2.0 mm). No statistically significant difference in yield and maximum load was found (P > .05).

CONCLUSION

The results of the present study do not support the authors' hypothesis. In the shear force test, horizontal sutures were superior to vertical suture techniques.

CLINICAL RELEVANCE

Meniscal repair with horizontal suture techniques can withstand elongation due to shear forces more effectively than can vertical mattress sutures.