Complications in medial meniscus suture: a cadaveric study

Knot location in arthroscopic inside-out meniscal repair: Cadaveric evaluation

BACKGROUND

The inside-out repair technique is the gold standard for treatment of meniscal tears, while some soft tissues can be hung as the sutures are tied outside the capsule. The purpose was to clarify the association between the suture site and knot location in the arthroscopic inside-out technique.

METHODS

Inside-out meniscal suture was arthroscopically performed on medial and lateral menisci in twenty-three cadaveric knees, on the assumption that longitudinal tear existed. A retractor was inserted above the semi-membranous tendon and anterior to the gastrocnemius for the medial side, while the retractor was placed in the anterior space of the gastrocnemius for the lateral side. After identifying three segments (anterior, middle and posterior segments), eight sutures were inserted into the following eight areas in each knee: anterior (M1, L1) and posterior (M2, L2) areas of the middle segment, and anterior (M3, L3) and posterior (M4, L4) areas of the posterior segment. Twelve knees underwent meniscal repair on femoral side and eleven passed sutures on the tibial side, while knots were tied outside of the joint. Attentive dissection was performed to assess the relation between knot locations and the principal structures around the knee joint.

RESULTS

In medial meniscal suture, most sutures for the middle portion (M1, 2) bound medial collateral ligament (MCL), while a few cases included the semi-membranous tendon for the M4 area. In lateral meniscal suture, sutures for the L1 area tied some fibers of lateral collateral ligament (LCL) in high frequency, while popliteal muscles/tendons were tied over at the L3 area.

CONCLUSIONS

Most suture knots were located on MCL or capsule in medial meniscus suture, while more than half sutures passed through LCL or popliteal tendon/muscle in lateral meniscus suture. An assistant should retract LCL under direct observation and the surgeon must confirm the direction of needle for lateral meniscal repair.

Ultrasound assessment of medial crural cutaneous nerve and infrapatellar branch and of the saphenous nerve: establishing a safety zone for preventing nerve injury in knee surgery and injections

PURPOSE

Our study aimed to illustrate the positional relationship of the two branches of the saphenous nerve: the infrapatellar branch of the saphenous nerve (IPBSN) and medial crural cutaneous nerve (MCCN), as well as the anatomical landmarks using high-resolution ultrasound (HRUS) to help prevent iatrogenic nerve injury.

METHODS

We used HRUS to explore the positional relationships among the anatomical landmarks, IPBSN, and MCCN in 40 knees of 20 participants. The distances from these branches to key reference points were recorded. Using the ultrasound caliper mode, we measured the depth from the skin surface to the nerves at four distinct points.

RESULTS

The average distances between IPBSN and medial border of patella (MBP) and IPBSN and medial border of patellar ligament (MBPL) were 47 ± 7 mm and 42 ± 9 mm, respectively. MCCN showed mean distances of 94 ± 9 mm and 96 ± 9 mm to MBP and MBPL, respectively. The mean distance from the upper edge of pes anserine to IPBSN at the patellar apex (PA) level was 24 ± 10 mm and to MCCN was 34 ± 9 mm.

CONCLUSION

We used high-resolution ultrasound to evaluate IPBSN and MCCN and their positions relative to anatomical landmarks. The study results offer valuable insights into the course of these nerves, which can help establish a safety zone to prevent accidental nerve injuries during knee surgeries and injections.

Using a Combined All-Inside, Inside-Out, and Outside-In Technique to Repair Bucket-Handle Medial Meniscal Tears Without a Safety Incision

We describe a combined all-inside, inside-out, and outside-in technique for the repair of unstable bucket-handle medial meniscal tears. Notably, a greater incidence of neurovascular complications has been associated with meniscal repair techniques that employ an accessory skin incision, especially when damage involves the body of the medial meniscus. However, with the operative knee in relative extension, passing inside-out needles anteromedial to the posterior horn and posterior to the semitendinosus tendon and saphenous nerve allows for the needles to exit the posteromedial knee through a "safe zone." Therefore, we reduce iatrogenic damage by avoiding the necessity of a large safety incision while still maintaining suture placement versatility and meniscal fragment stabilization. Thus, the objective of this Technical Note is to outline an efficient technique for treating bucket-handle medial meniscal tears that yields a strong, durable repair while avoiding damage to adjacent neurovascular structures and eliminating the need for a posteromedial safety incision.

Semimembranosus Tendon Entrapment by an All-Inside Meniscal Suture

Meniscal suturing has become the gold standard when it comes to meniscal tears in vascularized areas, especially in the younger population. The all-inside meniscal suturing technique has gained popularity in the past year due to decreased operative time as well as decreased risk of adverse events, as compared to other modalities. However, several complications have been reported with the all-inside technique, including soft tissue and neurovascular injury. This is the first case reporting a semimembranosus tendon entrapment following an all-inside medial meniscal suture. Being aware of such complications is crucial in order to avoid them and treat them promptly should they arise.

Inside-out Repair of Extensive Meniscal Tears Using Posteromedial and Posterolateral Neurovascular Protective Windows

Three popular repair techniques for preserving the torn meniscus are the all-inside, outside-in, and inside-out techniques. Among these, the inside-out technique has shown low failure rates, and it therefore remains the gold-standard technique for repairing the torn meniscus. For extensive and chronic meniscal tears, proper use of this technique has become fundamental for knee surgeons. Nevertheless, challenges in using this technique include a higher risk of catching the neurovascular bundles on the posteromedial and posterolateral sides of the knee and difficulties in reducing and stabilizing chronically displaced meniscal fragments. In this article, the inside-out technique is revisited with an emphasis on anatomic details of how to avoid the neurovascular bundles while addressing extensive and chronic meniscal lesions.

Prevalence, development, and factors associated with cyst formation after meniscal repair with the all-inside suture device

PURPOSE

To investigate the prevalence of cyst formation after using all-inside meniscal repair device and analysed the risk factors associated with it.

METHODS

Between August 2008 and September 2013, 51 menisci of 46 patients were included in the study, 46 menisci of which had concomitant anterior cruciate ligament (ACL) ruptures and had an ACL reconstruction. Magnetic resonance imaging (MRI) of the knee was performed at 3, 6, 12 and 24 months after meniscal surgery. The MRIs were assessed to detect the development of cysts encasing the suture anchors and to evaluate meniscal healing. Statistical analysis was performed using multiple regression analysis.

RESULTS

Out of the 51 menisci examined, MRI revealed cysts in 15 menisci. Cysts were detected in 3 menisci at 6 months, in 9 menisci at 12 months, and in 3 menisci at 24 months after surgery. Only 3 patients (6.5%) were symptomatic, and cystectomy was performed in 2 of these patients and arthroscopic debridement in the other. Compared with using both the suture device and an inside-out suture repair, using the suture device alone was more likely to be associated with cyst development [odds ratio (OR), 12.04]. The medial meniscus was also significantly more likely to develop a cyst compared with the lateral meniscus (OR, 12.48). There was an increased outcome for the number of device use (P = 0.033). Though it was not statistically significant, the patients with anterior knee laxity (side-to-side difference > 3 mm using a knee arthrometer) were more likely to develop cysts than those without anterior knee laxity (P = 0.06). There were no significant differences between the remaining variables.

CONCLUSIONS

The prevalence of cyst formation around the suture implant was 29%, but most cases were not symptomatic. Significant risk factors for cyst formation included the use of a suture device alone, and a location in the medial meniscus.

LEVEL OF EVIDENCE

III.

No safe zone: The anatomy of the saphenous nerve and its posteromedial branches

BACKGROUND

Following a case of medial meniscal repair via an inside-out repair, a patient developed acute postoperative electric shock-like paresthesias of the proximal medial calf with any knee flexion beyond 80°. Open saphenous nerve exploration revealed entrapment by suture material of an unnamed branch off the sartorial branch of the saphenous nerve. Symptoms resolved immediately with release. The objective of the study was to perform a cadaveric study to examine the existence and frequency of these previously under-reported branches of the sartorial branch of the saphenous nerve.

METHODS

In 16 knees from eight fresh, matched whole cadavers, the medial structures of the knee were exposed, reproducible anatomical structures were identified, and previously under-described posteromedial branches of the sartorial nerve were identified and measured in relation to surrounding structures and the joint line.

RESULTS

The saphenous nerve, its sartorial and infrapatellar branches, and its posteromedial branches were identified in all specimens. The sartorial nerve divided from the saphenous nerve an average of 4.8 cm proximal to the medial femoral epicondyle. Between one and four further posteromedial branches off the sartorial nerve were identified. These branches formed at a range of 5.3 cm proximal to 3.0 cm distal to the joint line.

CONCLUSIONS

This cadaveric study establishes the consistent presence of a posteromedial branch off the sartorial nerve. It was consistently located near the posteromedial joint line. These branches are at risk for injury during medial meniscus repairs due to entrapment by suture materials, or during other surgical procedures near the posteromedial aspect of the knee.

Popliteal neurovascular bundle is safe during inside-out repair of medial meniscus without a safety incision

PURPOSE

There is a theoretical risk of injury to neurovascular structures during inside-out meniscal repair without a safety incision, although there are limited studies assessing this risk. This simulation study on archival MRI films was performed to assess the risk for the popliteal neurovascular bundle and the peroneal nerve during passage of needles for inside-out meniscus repair without a "safety incision", thereby defining a "safe zone" of the menisci that can be safely repaired using this technique.

METHODS

Archival MRI scans (n = 50) were retrieved and axial sections through the menisci were used for simulation. The needle passage was simulated for different points on the posterior horn and body of lateral and medial menisci at "half-hour" intervals using clock method (15° intervals) with three different portals and two different needle cannulas, resulting in six different scenarios of needle passage for each point on the meniscus. The distance of the needle in each scenario was measured from popliteal vessels (n = 50) and peroneal nerve (n = 10). The value "mean-3SD" was calculated for positive means and "Mean + 3SD" was calculated if the mean was negative. An additional 2 mm was defined as "safe distance". Thus, simulation models in which the mean - 3SD was less than 2 mm (or mean + 3SD was greater than - 2 mm for negative means) were labelled as "unsafe".

RESULTS

Needle passage through medial meniscus at and medial to 1 o'clock position for a right knee (or 11 o'clock position for a left knee) was safe, irrespective of the portal and needle type. For the lateral meniscus, only the equatorial region was found to be safe with this method.

CONCLUSIONS

The popliteal neurovascular bundle is safe during the inside-out medial meniscal repair without a safety incision. For the terminal-most part of the posterior horn, the AM portal and the straight cannula should be avoided. However, this method without safety incision cannot be recommended for lateral meniscus because of the risk to the popliteal vessels and the peroneal nerve. Instead, the inside-out method with a safety incision, or an all-inside method should be used for lateral meniscus.

LEVEL OF EVIDENCE

III.

A review of main anatomical and sonographic features of subcutaneous nerve injuries related to orthopedic surgery

Lesion to subcutaneous nerves is a well-known risk of orthopedic surgery and a significant cause of postoperative pain and dissatisfaction in patients. High-resolution ultrasound can be used to visualize the vast majority of small subcutaneous nerves of the upper and lower limbs. Ultrasound detects nerve abnormalities such as focal hypoechoic thickening, stump neuroma, and scar encasement, and provides information not only about the peripheral nerve itself but also about its relationship to adjacent anatomical structures. The purpose of this review is to provide an overview of the anatomy of the main subcutaneous nerves damaged during orthopedic surgery, recall at-risk procedures, and offer useful anatomic landmarks to help the sonographer identify and follow the nerves when an iatrogenic lesion is suspected.

Tibiofemoral contact pressures in radial tears of the meniscus treated with all-inside repair, inside-out repair and partial meniscectomy

BACKGROUND

To test contact pressures in the knee after treatment of a radial meniscus tear with an all-inside meniscal repair technique and compare the results with inside-out repair and partial meniscectomy.

METHODS

Six non-paired cadaveric knees were analyzed with intra-compartment pressures measured at loads of 250 N, 500 N and 1000 N at 0°, eight degrees, 15°, and 30° of knee flexion. Compartmental contact pressures were measured for the intact medial meniscus, radial tear in the posterior horn, all-inside repair using the NovoStitch suture passer device (Ceterix Orthopaedics Inc., Menlo Park, CA), inside-out repair method, and partial meniscectomy. One-way ANOVA was used for statistical analysis.

RESULTS

The greatest differences in peak pressures between treatments were observed under 1000 N load at 30° flexion (0.8± (SD) 0.1 MPa (intact meniscus), 0.8± (SD) 0.1 MPa (all-inside), 0.9± (SD) 0.1 MPa (inside-out) and 1.6± (SD) 0.2 MPa (partial meniscectomy)). Treatment with partial meniscectomy resulted in the highest peak pressures compared to all other states (p<0.0001 at each angle). Repair of the radial tear using the all-inside technique as well as the inside-out technique resulted in significantly decreased compartment pressures compared to partial meniscectomies (p<0.0001 at each angle). There were no significant differences between peak pressures in the intact state and after repair with the all-inside or inside-out techniques.

CONCLUSION

An all-inside repair technique using the NovoStitch suture passer can decrease contact pressures for a radial meniscus tear similarly to the inside-out repair technique when compared to partial meniscectomy.

CLINICAL RELEVANCE

This novel arthroscopic suture passer warrants further analysis in the clinical setting as it may be a reliable method for repair of radial meniscal tears through an arthroscopic all-inside technique.

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.

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.

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.

Sartorial branch of the saphenous nerve in relation to a medial knee ligament repair or reconstruction

Surgical approaches to repair or reconstruct the medial knee structures note caution to avoid the sartorial branch of saphenous nerve. However, the approximate area of potential iatrogenic nerve injury has not been previously described in relation to landmarks for a medial knee reconstruction. The purpose of this study was to define the course of the sartorial branch of the saphenous nerve in relation to the superficial medial collateral ligament. A total of ten non-paired, fresh-frozen cadaveric knees, with no evidence of prior injury or disease were utilized. Dissection to identify the medial knee structures was performed. The sartorial branch of the saphenous nerve was identified in all specimens. The perpendicular distance from the anterior border of the superficial medial collateral ligament 2 cm distal from the joint line to the sartorial branch of the saphenous nerve was 4.8 +/- 0.9 cm. The distance from the anterior border of the superficial medial collateral ligament to the sartorial branch of the saphenous nerve decreased as the distance was increased distally with a mean distance of 4 cm (4.1 +/- 0.8 cm) distal from the joint line and 6 cm (3.8 +/- 0.8 cm) distal from the joint line. We have characterized the surgically relevant landmark anatomy of the sartorial branch of the saphenous nerve in regards to performing a repair or reconstruction of the medial knee structures. Familiarity with these anatomic landmarks and associated distances from the sartorial branch of the saphenous nerve, we can assess the potential area of vulnerability to this nerve branch intraoperatively.

Meniscal repair

The meniscus plays an important role in preventing osteoarthritis of the knee. Repair of a meniscal lesion should be strongly considered if the tear is peripheral and longitudinal, with concurrent anterior cruciate ligament reconstruction, and in younger patients. The probability of healing is decreased in complex or degenerative tears, central tears, and tears in unstable knees. Age or extension of the tear into the avascular area are not exclusion criteria. Numerous repair techniques are available, and suture repair seems to provide superior biomechanical stability. However, the clinical success rate does not correlate well with the mechanical strength of the repair technique. Biologic factors might be of greater importance to the success of meniscal repair than the surgical technique. Therefore, the decision on the most appropriate repair technique should not rely on biomechanical parameters alone. Contemporary all-inside repair systems have decreased the operating time and the level of surgical skill required. Despite the ease of use, there is a potential for complications because of the close proximity of vessels, nerves, and tendons, of which the surgeon should be aware. There is no clear consensus on postoperative rehabilitation. Weight bearing in extension would most likely not be crucial in typical longitudinal lesions. However, higher degrees of flexion, particularly with weight bearing, give rise to large excursions of the menisci and to shear motions, and should therefore be advised carefully. Long-term studies show a decline in success rates with time. Further studies are needed to clarify the factors relevant to the healing of the menisci. Tissue engineering techniques to enhance the healing in situ are promising but have not yet evolved to a practicable level.

All-inside suture technique using anterior portals in posterior horn tears of lateral meniscus

Methods for the repair of meniscal tears include inside-out, outside-in, and all-inside techniques. In this article an all-inside technique is proposed for the posterior horn of the lateral meniscus that takes advantage of the capacious posterolateral recess when the knee is flexed. A device consisting of a large needle with a buttonhole in the tip (previously used for inside-out suture of the medial meniscus) is used. This technique uses only anterior portals (anteromedial and anterolateral portals and an accessory lateral or transpatellar tendon portal). The arthroscope is inserted through the accessory portal. Once the tear has been located and its edges refreshed, the suture device is placed anterolaterally. The tip of the needle is loaded with suture and passed through both sides of the tear and into the posterolateral recess of the knee (without exiting the capsule). The suture tail is recovered with the use of a suture retriever through the anteromedial portal. Next, the suture retriever is inserted through the anterolateral portal to once again retrieve and shuttle the tail before completion of an arthroscopic knot. In addition to the ease of the technique, use of this simple, reusable device adds the benefit of low cost when compared with other techniques.