Biomechanical evaluation of arthroscopic all-inside meniscus repairs

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.

Evidence-based rationale for treatment of meniscal lesions in athletes

Meniscal injuries in elite athletes are a common cause of missed game time and even have the potential to be career shortening. In this patient group, care must be paid not only to the pathology, but also to a player's contract status, time in the season, specific demands of his/her sport and position on the field, and future consequences. Successful treatment requires the clinician to understand the player's goals and needs, communicate effectively between all stakeholders, and a have knowledge of the challenges posed by the different types of meniscal tear seen in this population. Paramount is the distinction between injuries to the medial and lateral meniscus. Deficiency of the lateral meniscus, as a result of a tear or a meniscectomy, leads to frequent early problems and inexorably to chondral degeneration thereby affecting an athlete's ability to perform. Therefore, it is strongly recommended to repair the majority of lateral meniscal tears. Medial meniscal tears pose a more challenging treatment dilemma, as the success of partial meniscectomy in achieving reproducible, early return to play must be balanced against the long-term degenerative consequences. Many meniscal tears are correctly treated non-operatively.Level of evidence V.

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).

Discoid meniscus: current concepts

Discoid meniscus is the most frequent congenital malformation of the menisci, and primarily affects the lateral meniscus; it is highly prevalent in the Asian population.The anatomic, vascular, and ultrastructural features of the discoid meniscus make it susceptible to complex tears.Discoid meniscus anomalies are described according to their shape; however, there is consensus that peripheral stability of the meniscus should also be defined.Initial workup includes plain X-rays and magnetic resonance imaging, while arthroscopic evaluation confirms shape and stability of the meniscus.Clinical presentation is highly variable, depending on shape, associated hypermobility, and concomitant meniscal tears.Treatment seeks to re-establish typical anatomy using saucerization, tear reparation, and stable fixation of the meniscus. Cite this article: EFORT Open Rev 2020;5:371-379. DOI: 10.1302/2058-5241.5.190023.

Evaluating the risk of popliteal artery injury in the all-inside meniscus repair based on the location of posterior meniscal lesions

The 'all-inside' meniscus repair is extremely useful technique in addressing tears at the far posterior horn of meniscus. However, this procedure may place the popliteal neurovascular bundle at risk of injury. The purpose of this study was to evaluate the risk of popliteal artery injury by the trajectory of anchor delivery instruments inserted through standard knee arthroscopic portals for the repair of the far posterior horn of meniscus tears. Standard arthroscopic portals were marked on five human cadaveric knees which were subsequently disarticulated. Axial photographs were taken after marking the 5 10, and 15 mm points from the meniscal root on the posterior horns of the menisci. The unsafe zones for meniscus repair at each of these points were identified on the photographs of knees by first drawing two lines from the edges of the popliteal artery and crossing at the respective points at the posterior horns. The points at which these lines meet a circular protractor applied to the center of each meniscus in the knee photograph were recorded as a range. The range signifies the unsafe zone for each respective point on the posterior horn of meniscus. The anterolateral arthroscopic portal fell within the unsafe zone of the 5 mm point on the posterior horn of lateral meniscus in three of the five knees and within the unsafe zone of the 10 mm point on the posterior horn of lateral meniscus in another two knees. A cautious approach should be practiced during the repair of tears located at these two points. None of the other points' unsafe zones (lateral 15 mm, medial 5 mm, 10 mm and 15 mm points) coincided with the ipsilateral portal sites. Level of evidence 5 (Human cadaveric study).

Novel flat and wide meniscal repair material improves the ultimate load of knot breakage in a porcine trans-capsular meniscal repair model

Background

In the meniscal repair procedures, a high ultimate load capacity and low cyclic creep at the repair site are favorable and lead to good biological incorporation of the tear site after surgery. Previous biomechanical tensile tests of the meniscal sutures have identified the suture knot as the weakest point. We hypothesized that the strength of a suture knot depends on the suture shape, and therefore, we compared three differently shaped suture materials composed of the same material and quantity per length. The purpose of this study was to determine whether a novel flat and wide repair material (FWRM), which consists of braided multi-threads that are cross-sectionally flat and wide, improves the ultimate load of knot breakage in a biomechanical experiment using a porcine trans-capsular meniscal repair model.

Methods

Eighteen fresh-frozen porcine knees (n = 6 in each group) were used. A longitudinal tear in the middle segment of the medial meniscus was created and repaired with a trans-capsular inside-out method using the following suture materials: No. 2–0 braided polyester conventional suture, hollow suture, and FWRM. After the separation of the inner segment of the meniscus with leaving, the suture stability of the repaired menisci was biomechanically analyzed with a video camera system for widening after a cyclic load between 5 and 20 N was applied 300 times. Ultimate failure load and stiffness at 5 mm/ min were also analyzed.

Results

We found no significant difference in suture widening after cyclic load tests [conventional suture, mean 0.51 mm (S.D. 0.39 mm); hollow suture, mean 0.23 mm (S.D. 0.11 mm); and FWRM, mean 0.54 mm (S.D. 0.08 mm)]. The failure mode in all specimens was knot breakage. Compared with those of the other groups, the ultimate failure load of FWRM was statistically significantly higher in the load-to-failure tests (conventional suture, mean 58.8 N [S.D. 8.25 N]; hollow suture, mean 79.4 N [S.D. 10.2 N]; and FWRM, mean 97.4 N [S.D. 3.65 N]; p < 0.05).

Conclusion

FWRM improves the ultimate load of knot breakage without altering stability. This material may contribute to safe and stable meniscus repair.

What Is the Optimal Minimum Penetration Depth for "All-Inside" Meniscal Repairs?

PURPOSE

To identify desired minimum depth setting for safe, effective placement of the all-inside meniscal suture anchors.

METHODS

Using 16 cadaveric knees and standard arthroscopic techniques, 3-dimensional surfaces of the meniscocapsular junction and posterior capsule were digitized. Using standard anteromedial and anterolateral portals, the distance from the meniscocapsular junction to the posterior capsule outer wall was measured for 3 locations along the posterior half of medial and lateral menisci. Multiple all-inside meniscal repairs were performed on 7 knees to determine an alternate measure of capsular thickness (X2) and compared with the digitized results.

RESULTS

In the digitized group, the distance (X1) from the capsular junction to the posterior capsular wall was averaged in both menisci for 3 regions using anteromedial and anterolateral portals. Mean distances of 6.4 to 8.8 mm were found for the lateral meniscus and 6.5 to 9.1 mm for the medial meniscus. The actual penetration depth was determined in the repair group and labeled X2. It showed a similar pattern to the variation seen in X1 by region, although it exceeded predicted distances an average 1.7 mm in the medial and 1.5 mm in the lateral meniscus owing to visible deformation of the capsule as it pierced.

CONCLUSIONS

Capsular thickness during arthroscopic repair measures approximately 6 to 9 mm (X1), with 1.5 to 2 mm additional depth needed to ensure penetration rather than bulging of the posterior capsule (X2), resulting in 8 to 10 mm minimum penetration depth range. Surgeons can add desired distance away from the meniscocapsular junction (L) at device implantation, finding optimal minimal setting for penetration depth (X2 + L), which for most repairable tears may be as short as 8 mm and not likely to be greater than 16 mm.

CLINICAL RELEVANCE

Minimum depth setting for optimal placement of all-inside meniscal suture anchors when performing all-inside repair of the medial or lateral meniscus reduces risk of harming adjacent structures secondary to overpenetration and underpenetration of the posterior capsule.

Long-term outcome after all-inside meniscal repair using the RapidLoc system

PURPOSE

The purpose of the present study was to evaluate the outcome at a minimum of 7 years following meniscal repair using the RapidLoc (suture anchor) system. It was hypothesized that most patients would have an intact meniscus, as has been reported in several short- and medium-term studies.

METHODS

In the time period from 2002 to 2007, all patients with a vertical longitudinal tear of the meniscus that was judged to be repairable were treated with rasping of the tear area and nearby parameniscal synovium and fixation of the torn part with the use of RapidLoc implants. Using a surgeon-administered form, baseline information about the arthroscopic findings and procedures performed was recorded (at the time of surgery). A median 10-year (range 7-12 years) follow-up was conducted in 2014-2015, and surgical procedures to the knee following the (index) meniscal repair were registered. Treatment failure was defined as a new surgical procedure to the same meniscus.

RESULTS

At the time of follow-up, 39 out of 82 patients (48 %) had undergone further surgery to the repaired meniscus (failures). Nine of these occurred within the first 6 months after surgery, 21 within the first 12 months and 26 within the first 24 months. Thus, the failure rate was 11 % at 6 months, 23 % at 12 months and 28 % at 2 years. One-third (N = 13) of the failures occurred 2 years or later after the (index) meniscal repair.

CONCLUSIONS

Long-term results of meniscal repair using the RapidLoc implants were found to be poor with a high failure rate. In a large proportion of the cases, re-rupture appeared several years after the index surgery, and a commonly used follow-up period of 2 years would therefore fail to detect them. In the day-by-day clinical work, of interest to orthopaedic surgeons is that meniscal repair using an all-inside technique similar to the one used by the authors may not solve the problem in the long run.

LEVEL OF EVIDENCE

IV.

Biomechanical Comparison of Parallel and Crossed Suture Repair for Longitudinal Meniscus Tears

Background:

Longitudinal meniscus tears are commonly encountered in clinical practice. Meniscus repair devices have been previously tested and presented; however, prior studies have not evaluated repair construct designs head to head. This study compared a new-generation meniscus repair device, SpeedCinch, with a similar established device, Fast-Fix 360, and a parallel repair construct to a crossed construct. Both devices utilize self-adjusting No. 2-0 ultra–high molecular weight polyethylene (UHMWPE) and 2 polyether ether ketone (PEEK) anchors.

Hypothesis:

Crossed suture repair constructs have higher failure loads and stiffness compared with simple parallel constructs. The newer repair device would exhibit similar performance to an established device.

Study Design:

Controlled laboratory study.

Methods:

Sutures were placed in an open fashion into the body and posterior horn regions of the medial and lateral menisci in 16 cadaveric knees. Evaluation of 2 repair devices and 2 repair constructs created 4 groups: 2 parallel vertical sutures created with the Fast-Fix 360 (2PFF), 2 crossed vertical sutures created with the Fast-Fix 360 (2XFF), 2 parallel vertical sutures created with the SpeedCinch (2PSC), and 2 crossed vertical sutures created with the SpeedCinch (2XSC). After open placement of the repair construct, each meniscus was explanted and tested to failure on a uniaxial material testing machine. All data were checked for normality of distribution, and 1-way analysis of variance by ranks was chosen to evaluate for statistical significance of maximum failure load and stiffness between groups. Statistical significance was defined as P < .05.

Results:

The mean maximum failure loads ± 95% CI (range) were 89.6 ± 16.3 N (125.7-47.8 N) (2PFF), 72.1 ± 11.7 N (103.4-47.6 N) (2XFF), 71.9 ± 15.5 N (109.4-41.3 N) (2PSC), and 79.5 ± 25.4 N (119.1-30.9 N) (2XSC). Interconstruct comparison revealed no statistical difference between all 4 constructs regarding maximum failure loads (P = .49). Stiffness values were also similar, with no statistical difference on comparison (P = .28).

Conclusion:

Both devices in the current study had similar failure load and stiffness when 2 vertical or 2 crossed sutures were tested in cadaveric human menisci.

Clinical Relevance:

Simple parallel vertical sutures perform similarly to crossed suture patterns at the time of implantation.

The Effect of Knee Flexion Angle on the Neurovascular Safety of All-Inside Lateral Meniscus Repair: A Cadaveric Study

PURPOSE

To evaluate if different knee flexion angles can modify the neurovascular injury risk during lateral meniscus repair.

METHODS

Twenty cadaveric knees were studied. An all-inside suture device (FasT-Fix; Smith & Nephew, Andover, MA) was placed at the posterior horn and at the medial and lateral limits of the popliteal hiatus. The minimal distances between the device and the popliteal artery and peroneal nerve were measured with the knee at 90°, 45°, and 0° of flexion through a limited posterolateral arthrotomy.

RESULTS

The distance between the device when inserted at the lateral edge of the popliteal hiatus and the peroneal nerve decreased from a median of 26 mm (interquartile range [IQR], 3.5 mm; range, 19 to 29 mm) at 90° to 21.5 mm (IQR, 4.5 mm; range, 14 to 25 mm) at 45° and 15.5 mm (IQR, 6.5 mm; range, 4 to 20 mm) at 0° (significant differences, P < .001). The distance between the device when inserted at the medial edge of the popliteal hiatus and the peroneal nerve decreased from 16 mm (IQR, 3.3 mm; range, 9 to 21 mm) at 90° to 12 mm (IQR, 4.3 mm; range, 9 to 16 mm) at 45° and 7 mm (IQR, 4.0; range, 4 to 15 mm) at 0° (significant differences, P < .001). The distance between the device when inserted at the medial edge of the popliteal hiatus and the popliteal artery decreased from 21 mm (IQR, 5.0 mm; range, 11 to 27 mm) at 90° to 19 mm (IQR, 5.0 mm; range, 10 to 23 mm) at 45° and 16 mm (IQR, 7.5 mm; range, 10 to 23 mm) at 0° (significant differences, P < .001). The distance between the device when inserted 5 mm lateral to the posterior root of the lateral meniscus and the popliteal artery decreased from 13 mm (IQR, 4.3 mm; range, 7 to 27 mm) at 90° to 10.5 mm (IQR, 4.3 mm; range, 4 to 19 mm) at 45° and 5.5 mm (IQR, 4.0 mm; range, 0 to 14 mm) at 0° (significant differences, P < .001).

CONCLUSIONS

The risk of injury to the popliteal artery or to the peroneal nerve during all-inside repair of the posterior half of the lateral meniscus is lower at 90° of flexion and increases with knee extension to 45° and 0°.

CLINICAL RELEVANCE

All-inside meniscal repair of the lateral meniscus is safer with the knee at 90° of flexion.

The Results of All-Inside Meniscus Repair Using the Viper Repair System Simultaneously with Anterior Cruciate Ligament Reconstruction

Background

Meniscus tears are commonly associated with anterior cruciate ligament (ACL) ruptures. It is essential to repair meniscal tears as much as possible to prevent early osteoarthritis and to gain additional stability in the knee joint. We evaluated the results of arthroscopic all-inside repair using the Meniscal Viper Repair System (Arthrex) on meniscus tears simultaneously with ACL reconstruction.

Methods

Nineteen out of 22 patients who were treated with arthroscopic all-inside repair using the Meniscal Viper Repair System for meniscus tear associated with ACL rupture were evaluated. ACL reconstructions were performed at the same period. The mean follow-up period was 16.5 months (range, 12 to 24 months). The clinical results of the meniscus repair were evaluated by symptoms (such as catching or locking), tenderness, effusion, range of motion limitation, and the McMurray test. Clinical success was defined by negative results in all five categories. The Hospital for Special Surgery (HSS) score was evaluated. Objective results were evaluated with secondary look arthroscopy or magnetic resonance imaging (MRI). The MRI results were categorized as completely repaired, incompletely repaired, and failure by Henning's classification. The results of second-look arthroscopy were evaluated with the criteria of meniscal healing.

Results

The clinical success rate was 95.4% and the HSS scores were 93.9 ± 5.4 at the final follow-up. According to Henning's classification, 15 out of 18 cases showed complete healing (83.3%) and two cases (11.1%) showed incomplete healing. Seventeen out of 18 cases that underwent second-look arthroscopy showed complete healing (94.4%) according to the criteria of meniscal healing. Only one case showed failure and the failure was due to a re-rupture at the sutured area. Complications of ACL reconstruction or meniscus repair were not present.

Conclusions

The results demonstrate that arthroscopic all-inside repair using the Meniscal Viper Repair System is an effective treatment method when it is performed simultaneously with ACL reconstruction.

What is the best way to fix a polyurethane meniscal scaffold? A biomechanical evaluation of different fixation modes

PURPOSE

Ingrowth of meniscal tissue into a meniscal scaffold can be optimized by securely fixing the scaffold into the meniscal remnants. The purpose of this research was to test and compare commonly used suture types and suture materials to fix a meniscal scaffold.

METHODS

Forty fresh porcine menisci were used. All tests used the same polyurethane-based scaffold. The load to failure of horizontal, vertical and diagonal sutures with PDS 0 and with Ethibond 0, and diagonal sutures with Ultra Fast-Fix(®) and Sequent(®) to fix a meniscal scaffold were tested. Five tests were conducted for each configuration.

RESULTS

All constructs failed in the scaffold at a mean pullout force of 50.6 N (SD 12.7). Inferior results were noted for vertical sutures (40.1 N, SD 6.3) compared to horizontal (49.8 N, SD 5.5, p = 0.0007) and diagonal (51.7 N, SD 15.6, p = 0.024) sutures and for Ethibond 0 (41.4 N, SD 6.2) compared to PDS 0 (51.3 N, SD 12.9, p = 0.001). When comparing the diagonal suture placements, only Ethibond 0 (42.9 N, SD 5.4) showed significantly inferior results compared to PDS 0 (60.1 N, SD 16.9, p = 0.03), Ultra Fast-Fix(®) (60.1 N, SD 9.3, p = 0.004) and Sequent(®) (65.8 N, SD 4.4, p < 0.0001).

CONCLUSIONS

The most common failure mode when fixing a polyurethane-based meniscal scaffold is suture pull-through of the scaffold in the distraction mode. This happens at a rather low pullout force and might preclude the use of this scaffold clinically. Vertical sutures and Ethibond 0 multifilament braided sutures fail at lower forces, and the tested commercial devices show promising results.

The concept of three-dimensional hold of both circumferential and radial collagen fibres of the meniscus

Collagen fibres of the meniscus arrange into two main orientations: circumferential fibres parallel to the long axis of the meniscus and radial fibres perpendicular to the long axis of the meniscus. Meniscal sutures are placed either in vertical or in horizontal orientations. Vertical sutures better hold circumferential fibres because it encircles them like a rope holding a bunch of tree branches. In the same manner, horizontal sutures better hold radial fibres. The "Simplified Cruciate Suture" consists of two vertical oblique sutures. Placing two vertical sutures in an oblique orientation captures greater meniscal tissue volume, holds and grasps both circumferential and radial collagen fibres of the meniscus into a three-dimensional plane with eventual high fixation strength of the repaired meniscal tear. Simplified cruciate suture is indicated for the repair of long bucket handle tears where it is placed in the middle of the tear like an anchor, and additional vertical and horizontal sutures are placed anterior and posterior to it as needed. Level of evidence V.

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.

Meniscal repair

Historically, treatment of meniscus tears consisted of complete meniscectomy. Over the past few decades, however, the long-term morbidities of meniscal removal, namely the early development of knee osteoarthritis, have become apparent. Thus, management of meniscal tears has trended toward meniscal preservation. Recent technological advances have made repairs of the meniscus easier and stronger. In addition, adjunctive therapies used to enhance the healing process have advanced greatly in the past few years. Today, with increased understanding of the impact of meniscal loss and the principles of meniscal repair and healing, meniscal preservation is viewed as an increasingly realistic and important goal in the management of meniscus tears.

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.

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.