Biofix arrow appearing as a subcutaneous foreign body

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.

Inside-out medial meniscus suture: an analysis of the risk of injury to the popliteal neurovascular bundle

PURPOSE

To assess the risk of damage to the popliteal neurovascular structures when inserting the needle through the posterior aspect of the knee during inside-out suture of the posterior horn of the medial meniscus.

METHODS

The first stage of our study consisted of simulating a virtual meniscal suture during magnetic resonance imaging by tracing a line from 3 different points (located medially [MP], centrally [CP], and laterally [LP] to the patellar tendon) to the posterior horn of the medial meniscus. This procedure was undertaken both at rest and with valgus stress. The next phase involved the suture of the posterior horns of medial menisci taken from cadaveric specimens, the needle being inserted through 3 separate locations (again located medially [MP], centrally [CP], and laterally [LP] to the patellar tendon). Finally, the distance from each suture thread to the aforementioned neurovascular bundle was measured.

RESULTS

During the magnetic resonance imaging study, the measured distances at rest were 26.4 mm for MP, 28.8 mm for CP, and 31 mm for LP, whereas those recorded with valgus stress were 21.7 mm for MP, 23.6 mm for CP, and 26 mm for LP. In the second phase of the study (cadaveric specimen suture), the distances obtained were 22.6 mm for MP, 27.6 mm for CP, and 33 mm for LP.

CONCLUSIONS

Our results indicate that when the needle is inserted through the 3 points investigated into the posteromedial region of the knee (10 mm from the posterior horn of the internal meniscus) during inside-out suture, it is far enough from the popliteal neurovascular bundle for the maneuver to be performed with a reasonable safety margin. However, this margin can be increased further still if the needle is inserted into the joint through a point located laterally to the patellar tendon.

CLINICAL RELEVANCE

Inside-out suture performed 10 mm from the posterior horn of the internal meniscus through the portals studied offers a sufficient margin of safety to avoid damage to the popliteal neurovascular bundle.

Long-term outcome after meniscal repair

PURPOSE

the purpose of this study was to analyse the clinical and radiological results of meniscal repairs and identify factors that correlate with the success of this procedure.

METHODS

a retrospective review of 119 meniscal repairs was completed. The average follow-up was 70 months. Successful meniscal repairs were observed critically in terms of radiographic changes and clinical outcomes and compared with failed meniscal repairs.

RESULTS

the overall success rate of meniscal repairs was 74%. Meniscal repairs that were performed within 6 weeks of injury had better results (83%) than late repairs (52%). The best results were obtained with the inside-out technique using #0 PDS suture (80%) compared to all-inside Biofix arrows (70%) and combined repairs (63%). Patients with associated ACL injury had a better chance of a successful outcome, but this was only significant when the ACL was reconstructed at the time of repair (P < 0.05). Those patients who had failed meniscal repair had increased radiographic osteoarthritic changes (81%) on long-term follow-up compared to patients with successful repair (14%).

CONCLUSION

this retrospective study shows the clinical and radiological importance of meniscal repair. Successful results in this study were associated with younger age and earlier repair using inside-out technique. Furthermore, increased success was seen in meniscal repairs performed in association with ACL reconstruction.

Articular contact pressures of meniscal repair techniques at various knee flexion angles

Articular cartilage injury can occur after meniscal repair with biodegradable implants. Previous contact pressure analyses of the knee have been based on the tibial side of the meniscus at limited knee flexion angles. We investigated articular contact pressures on the posterior femoral condyle with different knee flexion angles and surgical repair techniques. Medial meniscus tears were repaired in 30 fresh bovine knees. Knees were mounted on a 6-degrees-of-freedom jig and statically loaded to 200 N at 45 degrees, 70 degrees, 90 degrees, and 110 degrees of knee flexion under 3 conditions: intact meniscus, torn meniscus, and meniscus after repair. For each repair, 3 sutures or biodegradable implants were used. A pressure sensor was used to determine the contact area and peak pressure. Peak pressures over each implant position were measured. Peak pressure increased significantly as knee flexion increased in normal, injured, and repaired knees. The change in peak pressure in knees with implant repairs was significantly higher than suture repairs at all knee flexion angles. Articular contact pressure on the posterior femoral condyle increased with knee flexion. Avoidance of deep knee flexion angles postoperatively may limit increases in articular contact pressures and potential chondral injury.

Biomechanical evaluation of arthroscopic all-inside meniscus repairs

Viper is a new device for arthroscopically all-inside meniscal repairing. In previous studies about Viper device, procedures were not applied arthroscopically despite this device has been designed for arthroscopic application. In this study, we evaluated primary fixation strength of arthroscopically applied meniscal repair using Viper device to obtain better clinical relevance. Two centimeter in length meniscal tear 2-3 mm far from periferic edge of medial meniscus of 50 calves were created arthroscopically. The menisci were divided into five groups including 10 menisci in each. In group 1, tears were repaired by outside-in vertical loop suture technique with No: 0 PDS. Tears were fixed by all-inside vertical suture by using Viper device with No: 0 PDS in group 2. In meniscal implant groups, RapidLoc, H-Fix, and Clearfix were applied in groups 3,4, and 5, respectively. Primary fixation strength of repairing techniques were evaluated with bio-mechanical testing machine. Fixation strengths determined in groups 1 and 2 were detected as 145 +/- 13 and 136 +/- 33 N, respectively. There was no difference in pull-out strength between groups 1 and 2. Fixation strengths in these two groups were significantly higher compared to groups 3, 4, and 5. There was no significant difference between group 3 (33 +/- 6 N) and 5 (28 +/- 6 N) in terms of fixation strengths whereas fixation strengths of these two groups were significantly higher compared to group 4 (20 +/- 3 N) (P = 0.005, P = 0.018, respectively). All-inside vertical suture technique using Viper device revealed comparable primary fixation strength with outside-in vertical suture technique for meniscal repair. We suggest that the Viper device is safe and reliable for meniscal repair.

All-inside meniscal repair

All-inside meniscal repair has gained widespread popularity over recent years. The devices and techniques have rapidly evolved, resulting in increased ease of use and reduced surgical times and risk to the neurovascular structures. Despite these advances, inside-out suture repairs remain the current gold standard, with proven long-term results. All-inside techniques must continue to be compared to inside-out meniscal repair.

[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.

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

BACKGROUND

Recent all-inside meniscal repair devices are available, but in vivo studies with these devices are sparse.

HYPOTHESIS

The FasT-Fix has inferior meniscal healing compared with the inside-out suture technique in the goat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

After Institutional Review Board approval, 73 male castrated goats (Capra hircus) underwent a 2-cm meniscal incision and subsequent repair with the FasT-Fix device on one knee and inside-out meniscal repair on the contralateral knee. Both repairs used a vertical mattress suture technique. Access to the menisci was via an open technique with an extra-articular osteotomy of the medial collateral ligament origin on the femur. The animals were then allowed to ambulate unrestricted in a pasture after a 7-day stay in cages. Necropsy was carried out 6 months postoperatively, and the menisci and articular cartilage were studied with gross and microscopic inspection.

RESULTS

Nine of the 73 animals were excluded before necropsy. A total of 64 animals underwent necropsy, gross measurement of residual lesions, gross evaluation for chondral damage, histologic evaluation of meniscal repair, histologic evaluation of any adjacent inflammatory reaction to implants, and data analysis. Compared with the inside-out group, the FasT-Fix group had longer residual full-thickness defects (1.2 +/- 2.9 mm vs 0.2 +/- 1.1 mm; P = .011) and longer residual partial-thickness defects (8.4 +/- 6.3 mm vs 3.6 +/- 5.5 mm; P < .001). A total of 148 FasT-Fix devices were placed for 73 knees. Two devices were replaced for improper deployment. The device deployed and attached correctly 146 of 148 times for a success rate of 98.6%. There was no gross chondral damage and no histologic findings of inflammatory reaction to the implants with either technique.

CONCLUSIONS

The FasT-Fix meniscal repair had inferior meniscal healing results in this animal model. Previous studies using this animal model have paralleled clinical outcomes. Implantation of the FasT-Fix device does not damage adjacent femoral or tibial cartilage. The deployment of the FasT-Fix implant was simple and reproducible. There was no inflammatory reaction to the FasT-Fix implant.

CLINICAL RELEVANCE

The FasT-Fix meniscal repair has inferior meniscal healing results compared with the inside-out meniscal repair technique in the goat model. The clinical significance of this finding is not known. Further clinical study of the FasT-Fix implant is warranted.

Meniscal repair using an all-inside, rapidly absorbing, tensionable device

PURPOSE

The purpose of this study was to evaluate the clinical success rate of all-inside meniscal repairs using a rapidly absorbing device in patients undergoing concurrent anterior cruciate ligament (ACL) reconstructions.

METHODS

Patients with menisci repaired using the polydioxanone Mitek RapidLoc (Depuy Mitek, Raynham, MA) during concurrent ACL reconstruction were evaluated clinically 2 years following index surgery. We performed examinations on 38 meniscal tears in 30 patients using the International Knee Documentation Committee form and the Knee Disorders Subjective History visual analog scale. We also performed physical examinations for an effusion, joint line tenderness, McMurray's testing, and KT-1000 arthrometry (MEDmetric, San Diego, CA).

RESULTS

The clinical success rate for meniscal repair was 86.8% (33 of 38) at a mean follow-up of 30.4 months (range, 21 to 56 months). Univariate analysis revealed sex as the only predictive variable for failure; all failures occurred in male patients. Nonpredictive variables included tear length, type, and configuration; a duration of more than 3 months, compartment, zone, ligament graft choice, age, follow-up, Tegner score, and visual analog scale score.

CONCLUSIONS

The polydioxanone RapidLoc device was found to have a clinical success rate of 86.8%. These data suggest that the more rapidly absorbing polydioxanone device is effective for all-inside meniscal repair during concurrent ACL reconstruction.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Effectiveness of bioabsorbable arrows compared with inside-out suturing for vertical, reparable meniscal lesions: a randomized clinical trial

BACKGROUND

Techniques for repairing the meniscus include both open and arthroscopic techniques using sutures and bioabsorbable implants. The purpose of this study was to compare the effectiveness of inside-out suturing and bioabsorbable arrows for repair of vertical meniscal lesions.

STUDY DESIGN

Randomized controlled clinical trial; Level of evidence, 1.

METHODS

One hundred consecutive patients were randomly assigned to arrows (n = 51) or sutures (n = 49). Sixty-five percent of patients (31 sutures, 34 arrows) underwent a concomitant anterior cruciate ligament reconstruction. A blinded research associate conducted assessments at 6 weeks and 3, 6, 12, and 24 months postoperatively. The primary outcome was retear rate. Secondary outcomes included the Western Ontario Meniscal Evaluation Tool, Anterior Cruciate Ligament Quality of Life Outcome Measure, and side-to-side comparisons of flexion and extension.

RESULTS

At baseline, groups were similar in age, gender, time from injury to surgery, and length and location of tear. Mean follow-up was 28.0 +/- 8.4 months. There were 22 failed meniscal repairs (11 in each group), which did not represent a significant difference in the rate of failure between groups (P = .92). The mean quality of life scores and side-to-side differences in extension and flexion measurements were not significantly different between groups. Two patients from the arrow group crossed over into the suture group at the time of surgery because of technical difficulties with the device, and in 3 instances, a single suture was needed to keep the tear reduced while arrows were introduced. Two patients required reoperation for removal of a prominent, subcutaneous arrow, and 1 patient in the suture group suffered a transient peroneal nerve palsy during revision suturing.

CONCLUSION

At intermediate follow-up, there were no statistically significant differences in measured outcomes between meniscal suturing and arrows. Longer term follow-up is necessary to identify differences between these 2 treatments, particularly to estimate the incidence of articular surface damage in patients whose meniscal tear was repaired using arrows.

Biomedical devices in meniscal repair

Preservation of the menisci is increasingly emphasized in orthopedic care of the knee. Techniques are rapidly emerging that allow easier accomplishment of this goal. In particular, the development of all-inside arthroscopic meniscal repair devices has facilitated more ready repair. A number of laboratory and clinical studies have examined these devices and comparisons with more traditional techniques have been made. Numerous reports of potential complications from these new technologies have also been described in the literature. This review covers the current options for treatment of meniscal repair, laboratory and clinical data, and also potential complications.

Meniscal repair and transplantation: indications, techniques, rehabilitation, and clinical outcome

The purpose of this paper is to provide current knowledge regarding the indications, operative techniques, rehabilitation programs, and clinical outcomes of meniscus repair and transplantation procedures. Meniscus tears that occur in the periphery may be repaired using a variety of operative procedures with high success rates. Complex multiplanar tears that extend into the central one-third avascular zone can also be successfully repaired using a meticulous vertically divergent suture technique. The outcome of these repairs justifies preservation of meniscal tissue, especially in younger athletic individuals. Meniscal transplantation is a valid treatment option for patients who have undergone meniscectomy and have related tibiofemoral joint pain, or in whom articular cartilage deterioration in the meniscectomized compartment is present. Rehabilitation after these operations includes knee motion and quadriceps-strengthening exercises initiated the first day postoperatively. The initial goal is to prevent excessive weight bearing and joint compressive forces that could disrupt the healing meniscus repair or transplant. The protocol contains modifications according to the type of meniscal tear, if a concomitant procedure is done (such as a ligament reconstruction) or if noteworthy articular cartilage deterioration is present. Patients who have repairs of peripheral meniscus tears are generally progressed more rapidly than those who have repairs of tears extending in the central one-third region or those who undergo meniscal transplantation. The safety and effectiveness of the rehabilitation program has been demonstrated in several clinical studies. We recommend preservation of meniscal tissue, regardless of age, in active patients whenever possible.

All-inside meniscal repair using a new flexible, tensionable device

BACKGROUND

A new generation of flexible all-inside meniscal repair devices is available, but clinical studies with these devices are lacking.

HYPOTHESIS

The RapidLoc has an intermediate-term meniscal healing rate that is equivalent to literature reports of inside-out suture technique in patients undergoing concurrent anterior cruciate ligament reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Retrospective analysis was performed for 75 meniscal tears in 66 consecutive patients undergoing anterior cruciate ligament reconstruction who underwent meniscal repair with the RapidLoc. Patients with at least 2 years' follow-up were evaluated for symptoms suggestive of a meniscal tear and were assessed with the International Knee Documentation Committee form and the Knee Disorders Subjective History visual analog scale. Subjects were asked to return for a clinical examination to include evaluation for an effusion and joint line tenderness as well as McMurray test and KT-1000 arthrometry readings. Patients with symptoms consistent with meniscal repair failure underwent magnetic resonance arthrography and repeat arthroscopy.

RESULTS

Twenty patients with 21 meniscal tears were excluded, resulting in 54 meniscal tears in 46 patients. At a mean follow-up of 34.8 months, the clinical success rate for meniscal repair was 90.7% (49/54), with 5 failures requiring meniscectomy. Univariate analysis revealed predictive variables for failure: bucket-handle configuration, multiplanar tears, tear length greater than 2 cm, and chronicity longer than 3 months. Non-predictive variables included compartment, zone, ligament graft choice, gender, age, follow-up, and visual analog scale score. Analysis of healed patients revealed a negative correlation between chronicity of tear and International Knee Documentation Committee score.

CONCLUSIONS

The RapidLoc has an acceptable intermediate-term clinical healing rate in patients undergoing concurrent anterior cruciate ligament reconstruction. Predictive variables for failure should be considered during operative decision making.

Midterm results of meniscal repair using the BioStinger meniscal repair device

PURPOSE

The purpose of this study was to evaluate the midterm healing rate and any adverse events from meniscus repair using the BioStinger meniscus repair device (Linvatec, Largo, FL).

METHODS

A retrospective review of a consecutive series of meniscal repairs performed by a single surgeon using the BioStinger was conducted. The BioStinger is cannulated, made of molded poly L-lactic acid, and inserted over a needle into the meniscus tissue. Clinical results and adverse events were noted, and Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee (IKDC) activity scores were obtained on all patients.

RESULTS

Forty-one patients underwent 41 meniscal repairs with an average follow-up of 38.6 months (range, 24 to 69 months); 35 meniscus repairs were performed in conjunction with anterior cruciate ligament reconstruction and 6 in stable knees. Tears repaired were peripheral, posterior horn tears with an average length of 2 cm. Clinical evidence of meniscal healing was observed in 95% at the time of last follow-up. Six second-look arthroscopies were performed and 2 failures were found. All other patients were symptom free. At follow-up, the mean Tegner score was 6.1 (2.8 preoperative), IKDC activity score was 3.3 (2.1 preoperative), Lysholm score was 90.6 (48.7 preoperative), and the mean Cincinnati score was 86.7 (41.3 preoperative). Four patients had peripheral migration of the device without skin tenting or perforation; 3 underwent removal of the BioStinger from the soft tissues and the other resolved after 12 months.

CONCLUSIONS

The midterm clinical success rate was 95% using the BioStinger device. Adverse events were observed in few cases.

LEVEL OF EVIDENCE

Level IV, cases series.

Chondral injury due to migration of a Mitek RapidLoc meniscal repair implant after successful meniscal repair: a case report

A case of chondral lesion of the medial femoral condyle caused by a bioabsorbable Mitek RapidLoc meniscal repair implant is presented. Meniscal repair was quite successful, but migration of one of the implanted fixation devices resulted in chondral damage, 12 months postoperatively. All orthopaedic surgeons using these new devices should be aware of the possibility of chondral damage of the adjacent femoral condyles.

Delayed biodegradation of a meniscal screw

A biodegradable polylactide meniscal screw was removed 32 months after the original meniscal repair. It was then subjected to gel permeation chromatography and was found to have retained 64.7% of its original molecular weight. Although it is obvious that the manufacturers of biodegradable implants have succeeded in producing materials that retain their strength long enough to allow tissue healing, the question arises as to the true biodegradation time of the same implants.

Synovial cyst formation resulting from nonabsorbable meniscal repair devices for meniscal repair

Several arthroscopic meniscal repair techniques and devices have been developed during the past decade. The Mitek Meniscal Repair System (Mitek, Ethicon, Norderstedt, Germany) is one of these devices. We report a case of synovial cyst formation after medial meniscus repair with a nonabsorbable Mitek Meniscal Repair System. The cyst in the right knee developed 5 months after the meniscus repair. After excision of the synovial cysts and removal of these devices, the mass and pain of the knee were relieved. To our knowledge, this is the first report of synovial cyst formation resulting from this device.

"All-inside" meniscal repair devices: an experimental study in the goat model

BACKGROUND

Although the use of "all-inside" absorbable meniscal repair devices has become popular, numerous complications have been reported. The authors applied their well-established goat model to evaluate three "all-inside" meniscal repair devices.

METHODS

A "tear" was created in the medial meniscus of both knees in 26 goats. The animals were randomized into four groups, and the meniscus was treated as follows: (A) meniscal repair with Mitek Fastner, (B) meniscal repair with BioStinger, (C) meniscal repair with Mitek Clearfix Screw, and (D) no repair. All animals were sacrificed at 6 months postoperatively, and all specimens were carefully evaluated and results recorded and compared with historical results of meniscal repair with suture in this same animal model.

RESULTS

Meniscal repair results with all three all-inside devices studied were inferior to suture repair. Chondral injury was present in 75% to 100% of repairs with all-inside devices and none of the control specimens.

DISCUSSION

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CONCLUSION

Although new all-inside meniscal repair devices are relatively quick and easy, results may not be as good as with traditional suture techniques. The high rate of chondral injury associated with these devices in the goat model is worrisome for chondral damage in humans, especially in patients with smaller or tighter knees.

Outcomes after meniscal repair using the meniscus arrow in knees undergoing concurrent anterior cruciate ligament reconstruction

PURPOSE

To determine the healing rate of meniscal repair using the Meniscus Arrow (Bionx, Blue Bell, PA) in patients undergoing concurrent anterior cruciate ligament (ACL) reconstruction and to evaluate patient outcomes with the International Knee Documentation Committee (IKDC) form and a visual analog scale (VAS).

TYPE OF STUDY

Case series with outcomes analysis.

METHODS

We retrospectively analyzed 38 consecutive patients with 39 meniscal tears in knees undergoing concurrent endoscopic ACL reconstruction whose menisci were repaired with the Meniscus Arrow system. All meniscal tears were deemed amenable to repair according to length, stability, morphology, and zone of tear. There were 31 medial and 8 lateral meniscal tears, with an average tear length of 2.1 cm. An average of 2.5 arrows were used to repair each tear. All 39 tears were located in the posterior horn of the meniscus or extending into the body of the meniscus from the posterior horn. Follow-up was assessed by clinical examination, the knee disorders subjective history, VAS, and the IKDC evaluation form. Reconstructed ACL laxity was assessed by KT-2000 arthrometry and clinical evaluation.

RESULTS

At an average follow-up of 2.3 years (range, 18-39 months), 32 patients have been surveyed to date. The success rate was 90.6% (29 of 32 patients) with 3 patients going on to arthroscopic partial meniscectomy. KT-2000 arthrometry showed that sagittal knee laxity was less than 3 mm in all reconstructed knees. Clinical criteria for success in the rest of the repaired menisci included (1) the absence of locking, catching, or giving way; (2) no history of recurrent effusions; (3) no joint line tenderness; (4) a negative McMurray test; and (5) no subsequent surgical procedures on the repaired meniscus. Additionally, the VAS showed the ability of these patients to return to a high level of activity, including competitive sports, without symptoms suggestive of a meniscal tear. The IKDC showed normal or nearly normal function of all success knees.

CONCLUSIONS

The study shows that a high rate of meniscus healing can be achieved by the all-inside, bioabsorbable Meniscus Arrow system in conjunction with ACL reconstruction. Also, patients have excellent function of their knee and are able to return to a high level of activity. Our healing rates are comparable to those previously reported with the inside-out suture techniques without the need for an additional posterior incision that would increase operative time and risk to neurovascular structures.