Postoperative change in medial meniscal length in concurrent all-inside meniscus repair with anterior cruciate ligament reconstruction

Effect of inside-out meniscal repair on meniscal dimension in meniscal tear patients

Background

It remains controversial whether meniscal repair causes meniscal extrusion. This study aimed to investigate the effect of inside-out meniscal repair on meniscal dimensions in patients with meniscal tear of the mid-body-posterior horn.

Methods

This retrospective study included 75 patients who underwent meniscal repair followed by MRI within 2 weeks after surgery between 2020 and 2022. Patients with a discoid lateral meniscus, pull-out repair, concomitant osteotomy, all-inside repair only, and revision surgery were excluded. Thirty-three meniscal tear treated using an inside-out arthroscopic repair technique were included in the lateral meniscus (LM, n = 19) and medial meniscus (MM, n = 14) tear groups. Thirty-six participants with intact meniscus were included as controls. Meniscal extrusion and posterior shift were measured on coronal and sagittal MRI pre-operatively and within 2 weeks postoperatively.

Results

Preoperative coronal extrusion was significantly greater in the LM tear group than in the control group (P = 0.001). Coronal extrusion and posterior shift were significantly smaller postoperatively than preoperatively in the LM tear group (P < 0.001 and, P = 0.008, respectively). Pre- and postoperative coronal extrusion in the MM tear group were not significantly different (P = 0.291). Postoperative coronal extrusion in both LM and MM tear groups were not significantly correlated with the number of sutures required for repair (LM: P = 0.765, R = -0.076, MM: P = 0.1, R = 0.497).

Conclusions

The torn meniscus of the mid-body - posterior horn before surgery was extruded and shifted posteriorly in both LM and MM tears, and repair using an inside-out arthroscopic technique was effective in reducing meniscal extrusion and posteriors shift in the LM tear immediately after surgery.

Searching for the Best Treatment for Ramp Lesions: A Systematic Review and Network Meta-Analysis

Ramp lesions are a common occurrence in patients with anterior cruciate ligament (ACL) tears. These lesions can be difficult to diagnose due to their concealed nature, and their treatment is crucial due to the stabilizing function of the medial meniscocapsular region. The optimal treatment option for ramp lesions varies depending on the size and stability of the lesion. The purpose of this study was to evaluate the best treatment option for ramp lesions based on the stability of the lesion, including no treatment, biological treatment, and arthroscopic repair. We hypothesize that stable lesions have a favorable prognosis with techniques that do not require the use of meniscal sutures. In contrast, unstable lesions require appropriate fixation, either through an anterior or posteromedial portal. This study is a systematic review and meta-analysis with a level of evidence IV. The study used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for a systematic review of clinical studies reporting outcomes of ramp lesion treatment. The PubMed/MEDLINE database was searched using Mesh and non-Mesh terms related to ramp lesions, medial meniscus ramp lesions, and meniscocapsular injuries. The inclusion criteria encompassed clinical studies in English or Spanish that reported the treatment of ramp meniscal lesions, with a follow-up of at least six months and inclusion of functional results, clinical stability tests, radiological evaluation, or arthroscopic second look. The analysis included 13 studies with 1614 patients. Five studies distinguished between stable and unstable ramp lesions using different criteria (displacement or size) for assessment. Of the stable lesions, 90 cases received no treatment, 64 cases were treated biologically (debridement, edge-curettage, or trephination), and 728 lesions were repaired. There were 221 repaired unstable lesions. All different methods of repair were registered. In stable lesions, three studies were included in a network meta-analysis. The best-estimated treatment for stable lesions was biological (SUCRA 0.9), followed by repair (SUCRA 0.6), and no treatment (SUCRA 0). In unstable lesions, seven studies using International Knee Documentation Committee Subjective Knee Form (IKDC) and 10 studies using Lysholm for functional outcomes showed significant improvement from preoperative to postoperative scores after repair, with no differences between repairing methods. We recommend simplifying the classification of ramp lesions as stable or unstable to determine treatment. Biological treatment is preferred for stable lesions rather than leaving them in situ. Unstable lesions, on the other hand, require repair, which has been associated with excellent functional outcomes and healing rates.

Surgical Repair of Symptomatic Wrisberg Variant Discoid Lateral Mensicus with Pull-Out Repair and Capsulodesis

Wrisberg variant discoid lateral meniscus (DLM) is a congenital anatomic variation of the meniscus in the knee joint, which is an uncommon type of the DLM. We present a surgical technique in a case of symptomatic Wrisberg variant DLM. To improve the instability due to the lack of the posterior attachment of meniscotibial ligament, the posterior portion of DLM was attached to the insertion site of normal LM posterior root using pull-out repair technique. In addition, a longitudinal tear from the anterior to the middle portion of DLM was repaired with outside-in and inside-out techniques. Finally, a capsulodesis using knotless anchors was performed from outside of the joint to prevent the meniscus extrusion after the surgery. Knee symptoms such as pain, catching, and ROM restriction disappeared at 3 months after the surgery. Postoperative magnetic resonance imaging showed a slightly sharpened shape of the DLM, and the attachment of the posterior portion of the DLM was observed. Longitudinal tear of the DLM was healed without cleavage. This procedure is useful to improve the symptoms of the knee joint with Wrisberg variant DLM and to preserve the function of the meniscus.

A characteristic MRI finding to diagnose a partial tear of the medial meniscus posterior root: an ocarina sign

BACKGROUND

Diagnosing partial tears of the medial meniscus (MM) posterior root is difficult. The aim of this study was to evaluate diagnostic values involved in conventional magnetic resonance imaging (MRI) features of MM posterior root tears (MMPRTs) and find other MRI-based findings in patients with partial MMPRTs.

METHODS

Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. As a control, 18 patients who underwent partial meniscectomy for other types of MM tears were evaluated. Isolated partial MMPRTs were classified into the following three types: type A, accurate partial stable tear (cleavage < 1/2 of root width); type B, bridged unstable root tear (cleavage ≥ 1/2 of root width); type C, complex horn tear expanded to the root. Conventional MRI-based findings of MMPRTs were evaluated between two groups (n = 23). Posterior root irregularity, bone marrow spot, and ocarina-like appearance showing several condensed circles in triangular meniscal horn (ocarina sign) were also evaluated.

RESULTS

Posterior root irregularity and bone marrow spot were frequently observed in the partial MMPRTs (47.8%), compared with the other MM tears (P = 0.007 and 0.023, respectively). The ocarina sign was detected in 69.6% of patients with partial MMPRTs. A significant difference between two groups was observed in a positive ratio of ocarina sign (P < 0.001). Types A, B, and C of the partial tear/damage were observed in three, eight, and seven patients, respectively. The ocarina sign was the most common MRI finding in each type of partial MMPRT.

CONCLUSIONS

This study demonstrated that a characteristic MRI finding, "ocarina sign," was frequently observed in patients with partial tear/damage of the MM posterior root. The ocarina sign was the most common MRI finding in several types of partial MMPRTs. Our results suggest that the ocarina sign may be useful to diagnose unnoticed partial MMPRTs.

LEVEL OF EVIDENCE

IV, retrospective comparative study.

Steep posterior slope of the medial tibial plateau is associated with ramp lesions of the medial meniscus and a concomitant anterior cruciate ligament injury

Background

Medial meniscus (MM) tears are associated with both acute and chronic anterior cruciate ligament (ACL) insufficiency and can lead to degenerative changes in the knee. ACL reconstruction (ACLR) combined with the meniscal repair was reported to result in decreased anterior knee joint laxity with evidence of improved patient-reported outcomes in the long term. However, a subtle tear of the MM posterior segment, also known as a ramp lesion, is difficult to detect on conventional magnetic resonance imaging (MRI) and is frequently missed in ACL-deficient knees. However, there are few studies about the associations between bone geometry and ramp lesion of the MM. This study aimed to compare sagittal medial tibial slope (MTS), medial tibial plateau depth (MTPD), and coronal tibial slope (CTS) between ACL-injured knees with and without ramp lesion of the MM. We hypothesised that patients with ramp lesion of the MM and a concomitant ACL injury have a steeper MTS and shallower MTPD than those without ramp lesion of the MM.

Methods

Twenty-seven patients who underwent ACLR (group A), and 15 patients with combined MM repair (group AM) were included in the study. Anterior tibial translation (ATT) was measured under general anaesthesia just before surgery using a knee arthrometer. MRI was performed in the 10°-knee-flexed position. The MTS and MTPD were measured on sagittal view, and the CTS was measured on coronal view. These parameters were compared between the groups. Differences in MRI measurements or patient demographics between the groups were evaluated using the Mann-Whitney U test.

Results

No significant difference was observed in demographic data and post-operative side-to-side difference in ATT between both groups. Pre-operative ATT was significantly higher in group AM than in group A (P < 0.05), whereas post-operative ATT was similar in both groups. Further, Pre-operative ATT was significantly higher in patients with MTS ≥5.0° than in those with MTS <5.0° (P < 0.05). In groups A and AM, the MTS were 3.6° ± 1.8° and 6.2° ± 2.9°, the MTPD were 2.0 ± 0.5 mm and 2.1 ± 0.6 mm, and the CTS were 2.5° ± 1.8° and 2.4° ± 1.6°, respectively. Patients in group AM had a significantly steeper MTS compared to those in group A (P < 0.01), whereas MTPD and CTS were nearly the same in both groups. When the MTS cut-off value was set at 5.0°, the sensitivity and specificity for ACL injury with concomitant ramp lesion of the MM were 0.73 and 0.76, respectively.

Conclusion

A steep posterior slope of the medial tibial plateau is a risk factor for ramp lesion of the MM associated with an ACL injury. Especially in patients with MTS ≥5.0°, an occult MM ramp lesion should be strongly suspected, and surgeons should prepare for MM repair in combination with ACLR.

Return to Play After Isolated Meniscal Repairs in Athletes: A Systematic Review

Background:

Meniscal tears are a common knee injury. Isolated meniscal tears are less common; however, unaddressed tears can be troublesome, particularly for athletes. There is currently a lack of data in the literature on athletes returning to play after isolated meniscal repair.

Purpose:

To evaluate the return to play rate and time to return to play for athletes with isolated meniscal injuries.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A search of the PubMed, EMBASE, and Cochrane electronic databases was conducted to identify studies that reported the time and the rate of return to play in athletes after repair of isolated meniscal tears. Studies were excluded if there was a concomitant anterior cruciate ligament reconstruction, if there was a meniscectomy instead of a meniscal repair, or if the study was a systematic review. Quality assessment and data extraction were performed by 2 examiners.

Results:

Overall, 21 studies were included in this review. There were 355 athletes (358 knees) with a mean age of 22.5 years (range, 9-68 years). A sex breakdown was noted in 16 of the 21 (76.2%) studies with 224 men and 71 women. The specific repair technique was described in 259 (72.3%) knees. Of the total knees, 109 (30.4%) had an open repair, 128 (35.8%) had an inside-out arthroscopic technique repair, and 22 (6.1%) had an all-inside arthroscopic technique repair. Complications were addressed in 11 studies, with 13 out of 155 (8.4%) patients across the 11 articles having a postoperative complication. Of the total 355 patients, 295 (83.1%) returned to play, and 17 of these 21 (81.0%) articles reported the time it took for athletes to return to play, with a mean return of 8.7 months.

Conclusion:

The study results indicate that return to play rates after isolated meniscal repair are high, with an overall return to play rate of 83.1% and a mean return to play time of 8.7 months. However, the limited number of studies, particularly ones with larger patient numbers, highlights the need for further investigation regarding isolated meniscal repair in athletes.

Medial meniscus posterior root tear causes swelling of the medial meniscus and expansion of the extruded meniscus: a comparative analysis between 2D and 3D MRI

PURPOSE

This study aimed to clarify the advantages of three-dimensional (3D) magnetic resonance imaging (MRI) over two-dimensional (2D) MRI in measuring the size of the medial meniscus (MM) and to analyse the volumes of MM and the extruded meniscus in patients with MM posterior root tear (MMPRT), at 10° and 90° knee flexion.

METHODS

This study included 17 patients with MMPRTs and 15 volunteers with uninjured knees. The MMs were manually segmented for 3D reconstruction; thereafter, the extruded part separated from the tibial edge was determined. The length, width, height, and extrusion of MM were measured by the 2D and 3D methods, and compared. The MM volume, extruded meniscus volume, and their ratio were also calculated using 3D analysis software in the two groups.

RESULTS

The estimated length and posterior height of MM were larger with 3D MRI than with 2D MRI measurements. The MM volume was significantly greater in MMPRT knees than in normal knees, with increasing MM height. In MMPRT knees, the mean volume of the extruded meniscus and its ratio significantly increased by 304 mm³ (p = 0.02) and 9.1% (p < 0.01), respectively, during knee flexion.

CONCLUSIONS

This study demonstrated that 3D MRI could estimate the precise MM size and that MMPRT caused swelling of the meniscus due to the increased thickness in the posteromedial part. The clinical significance of this study lies in its 3D evaluation of MM volume, which should help the surgeon understand the biomechanical failure of MM function and improve MMPRT repair technique.

LEVEL OF EVIDENCE

III.

Ramp lesions: a systematic review of MRI diagnostic accuracy and treatment efficacy

Purpose

We conducted a systematic review of the published literature to assess the accuracy of Magnetic Resonance Imaging (MRI) in establishing the presence of ramp lesions (RLs) in Anterior Cruciate Ligament (ACL) deficient knees and the clinical efficacy of the surgical repair of RLs.

Methods

A comprehensive search of the MEDLINE, Web of Science and Scopus databases was performed according to PRISMA guidelines. Studies assessing MRI diagnostic accuracy for RLs or the clinical effect of RL repair in participants with ACL injuries were included. Diagnostic accuracy measures were pooled and plotted in forest plots. Preoperative and at last follow-up treatment efficacy outcome measures were extracted and plotted in forest plots, for graphical comprehension.

Results

Sixteen studies met the criteria and were included. The diagnostic analysis showed a pooled sensitivity, specificity, positive and negative likelihood ratios of 65.1% (95% CI, 59.73 to 70.42), 91.6% (95% CI, 89.14 to 94.05), 2.91 (95% CI, 2.38–3.55) and 0.53 (95% CI, 0.44–0.64), respectively, with high heterogeneity (I² above 80%) for all measures. Treatment analysis showed improved Lysholm Knee Score, IKDC score and laxity difference between the knees in all studies after meniscal suture repair. A separate analysis showed no differences between repair of smaller, stable, RLs with meniscal sutures and repair with abrasion and trephination only.

Conclusion

Although the results present considerable heterogeneity, MRI seems to demonstrate moderate accuracy in the diagnosis of RLs in patients with ACL tear and the surgical repair of RLs can be associated with improved overall outcomes.

Ramp lesions are frequently missed in ACL-deficient knees and should be repaired in case of instability

PURPOSE

The aim of the current study was (1) to provide an overview of common definitions and classification systems of ramp lesions (RL) and (2) to systematically review the available literature with regard to the diagnosis and treatment of RLs in anterior cruciate ligament (ACL)-deficient knees.

METHODS

Following the PRISMA guidelines, MEDLINE and Scopus were searched for articles (1) reporting on acute or chronic ACL injuries, (2) with concomitant medial meniscus injury, (3) located at the posterior meniscocapsular attachment site (and red-red zone). Ex vivo studies, reviews and technical notes were excluded.

RESULTS

Twenty-seven studies were included based on the criteria mentioned above. RLs are common in ACL-deficient knees with a prevalence ranging from 9 to 24%. RLs should especially be suspected in younger patients, patients with an increased meniscal slope and in patients with prolonged time from injury to surgery. The sensitivity of MRI for the detection of RLs ranges from 48 to 86% at a specificity of 79-99%. For arthroscopy, RLs are easily missed through standard anterior portals (sensitivity 0-38%). RL repair leads to a significant improvement of subjective knee scores, regardless of the specific fixation technique. For stable RLs, the literature suggests equivalent postoperative stability for trephination and abrasion compared to surgical RL repair.

CONCLUSION

Ramp lesions are frequently missed in ACL-deficient knees on standard arthroscopy with anterior portals only. If a RL is suspected, exploration via an additional posteromedial portal is indicated. In case of instability, RL repair should be performed.

LEVEL OF EVIDENCE

IV.

The effect of a longitudinal tear of the medial meniscus on medial meniscal extrusion in anterior cruciate ligament injury patients

PURPOSE

The purpose of this study was to investigate the effect of a longitudinal tear of the medial meniscus (MM) and its meniscal repair on MM extrusion in anterior cruciate ligament (ACL)-injured patients. The hypothesis underlying this study was that a longitudinal tear of the MM is correlated with MM extrusion, and that the extrusion would persist after ACL reconstruction with concomitant MM repair.

METHODS

Forty-three ACL-injured patients with a concomitant MM longitudinal tear were included in the MM tear group. Thirty-four solely ACL-injured patients without any meniscal injuries were included in the Control group. Medial meniscus extrusion width (MEW) was measured pre-operatively and three months after surgery on magnetic resonance imaging.

RESULTS

Pre-operative MEW in the MM tear group was significantly larger than that in the Control group (MM tear group: 1.5 mm, Control: 0.3 mm, P < 0.001). The MEW change in the MM tear group was significantly greater than that in the Control group three months after operation (MM tear group: 0.8 mm, Control: -0.2 mm, P < 0.001). The number of sutures required for repair was correlated with MEW both pre-operatively and postoperatively in the MM tear group (pre-operative: P = 0.005, R = 0.42, postoperative: P < 0.001, R = 0.54).

CONCLUSION

Longitudinal tear of the MM was correlated with MM extrusion and the MM extrusion persisted after ACL reconstruction with concomitant MM repair in the MM tear group. The initial meniscal tear size was directly correlated with the pre-operative MEW. Therefore, meniscal extrusion after longitudinal tears of the medial meniscus should be taken into careful consideration.

Posttraumatic cartilage degradation progresses following anterior cruciate ligament reconstruction: A second-look arthroscopic evaluation

BACKGROUND

Several studies have demonstrated that posttraumatic knee osteoarthritis progresses even after anterior cruciate ligament reconstruction. Few reports described zone-specific cartilaginous damages after anterior cruciate ligament reconstruction. This study aimed to compare the status of articular cartilage at anterior cruciate ligament reconstruction with that at second-look arthroscopy.

METHODS

This study included 20 patients (20 knees, 10 males and 10 females, mean age 22.4 years, Body mass index 24.4 kg/m²) that underwent arthroscopic anatomic double-bundle anterior cruciate ligament reconstruction and second-look arthroscopy. Mean periods from injury to reconstruction and from reconstruction to second-look arthroscopy were 3.4 and 15.3 months, respectively. Cartilage lesions were evaluated arthroscopically in the 6 articular surfaces and 40 articular subcompartments independently, and these features were graded with the International Cartilage Repair Society articular cartilage injury classification; comparisons were made between the grades at reconstruction and at second-look arthroscopy. Furthermore, clinical outcomes were assessed at reconstruction and at second-look arthroscopy, using the Lysholm knee score, Tegner activity scale, International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, side-to-side difference of the KT-2000 arthrometer, and pivot shift test.

RESULTS

Each compartment showed a deteriorated condition at second-look arthroscopy compared with the pre-reconstruction period. A significant worsening of the articular cartilage was noted in all compartments except the lateral tibial plateau and was also observed in the central region of the medial femoral condyle and trochlea after reconstruction. However, each clinical outcome was significantly improved postoperatively.

CONCLUSIONS

Good cartilage conditions were restored in most subcompartments at second-look arthroscopy. Furthermore, posttraumatic osteoarthritic changes in the patellofemoral and medial compartments progressed even in the early postoperative period, although good knee stability and clinical outcomes were obtained. Care is necessary regarding the progression of osteoarthritis and the appearance of knee symptoms in patients undergoing anterior cruciate ligament reconstruction.

Injury patterns of medial meniscus posterior root tears

INTRODUCTION

Medial meniscus posterior root tear (MMPRT) can occur in middle-aged patients who have a posteromedial painful popping during light activities. MMPRTs are more common in patients with increased age, female gender, sedentary lifestyle, obesity, and varus knee alignment. However, injury mechanisms of minor traumatic MMPRTs are still unclear. We hypothesized that high flexion activities are the major cause of MMPRTs. The aim of this study was to clarify injury patterns of MMPRTs.

MATERIALS AND METHODS

One hundred patients were diagnosed having MMPRTs after posteromedial painful popping episodes. Details of posteromedial painful popping episode, situation of injury, and position of injured leg were obtained from the patients by careful interviews. Injury patterns were divided into 8 groups: descending knee motion, walking, squatting, standing up action, falling down, twisting, light exercise, and minor automobile accident.

RESULTS

A descending knee motion was the most common cause of MMPRTs (38%) followed by a walking injury pattern (18%) and a squatting action related to high flexion activities of the knee (13%). The other injury patterns were less than 10%.

DISCUSSION

Descending knee motions associated with descending stairs, step, and downhill slope are the most common injury pattern of MMPRTs. High flexion activities of the knee are not the greatest cause of MMPRTs. Our results suggest that the descending action with a low knee flexion angle may trigger minor traumatic MMPRTs.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

Meniscal repair concurrent with anterior cruciate ligament reconstruction restores posterior shift of the medial meniscus in the knee-flexed position

PURPOSE

The purpose of this study was to evaluate the shape and shift of the medial meniscus before and after meniscal repair concurrent with anterior cruciate ligament (ACL) reconstruction using magnetic resonance imaging (MRI) at 90° of knee flexion.

METHODS

This study included 18 patients with ACL-deficient knees without meniscus tears (group A), 11 patients with medial meniscus tears alone (group M), and 15 patients with ACL-deficient knees complicated with medial meniscus tears (group AM). The posterior segment shape was evaluated using open MRI at 90° of knee flexion preoperatively and at 3 months postoperatively. The length, height, width, and posterior extrusion of the medial meniscus and posterior tibiofemoral distance were measured. These measurements were compared between the three groups.

RESULTS

On preoperative MRI, a significant difference was observed in the posterior extrusion of the medial meniscus (group A, 1.2 ± 0.5 mm; group M, 1.7 ± 0.3 mm; group AM, 4.1 ± 1.5 mm, p < 0.001). All parameters did not differ between the three groups on postoperative MRI. In addition, the posterior width and extrusion of the medial meniscus were decreased significantly after meniscal repair concurrent with ACL reconstruction.

CONCLUSIONS

This study demonstrated that the medial meniscus shifted posteriorly at 90° of knee flexion in ACL-deficient knees complicated with medial meniscus tears. Medial meniscal repair concurrent with ACL reconstruction improved the deformed morphology and posterior extrusion. MRI measurements of the posterior extrusion at the knee-flexed position may be clinically useful to assess the functional improvement of the medial meniscus following meniscal repair combined with ACL reconstruction.

LEVEL OF EVIDENCE

III.

Complete tear of the lateral meniscus posterior root is associated with meniscal extrusion in anterior cruciate ligament deficient knees

This study aimed to evaluate the relationship between preoperative lateral meniscal extrusion (LME) and arthroscopic findings of lateral meniscus posterior root tear (LMPRT) in knees with anterior cruciate ligament (ACL) tear. Thirty-five knees that had LMPRTs with concomitant ACL tears on arthroscopy were evaluated. Patients were divided into two groups, partial and complete root tears, via arthroscopic findings at the time of ACL reconstruction. For comparison, we added two groups, using the same database; 20 normal knees (normal group) and 20 ACL-injured knees without LM injury (intact LM group). We retrospectively measured preoperative LMEs using magnetic resonance imaging (MRI). Twenty-three knees had partial LMPRTs. Complete LMPRTs were observed in 12 knees. The average LME was -0.1 ± 0.4 mm in the normal group, 0.2 ± 0.5 mm in the intact LM group, 0.4 ± 0.8 mm in the partial LMPRT group, and 2.0 ± 0.6 mm in the complete LMPRT group. A significant difference in preoperative LMEs was observed between the complete LMPRT group and the other groups (p < 0.001). The receiver operating curve analysis, which distinguishes a partial tear from a complete tear, identified an optimal cut-off point of 1.1 mm for preoperative LME. This LME cut-off had a sensitivity of 100% and specificity of 83% for complete LMPRT. We found that preoperative LMEs were larger in complete LMPRTs associated with ACL injuries than in partial LMPRTs. Our results suggest that preoperative MRI-detected LME may be a useful indicator for estimating LMPRT severity in ACL-injured knees.

LEVEL OF EVIDENCE

Retrospective comparative study level IV. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1894-1900, 2018.

Improvement in the medial meniscus posterior shift following anterior cruciate ligament reconstruction

PURPOSE

Anterior cruciate ligament (ACL) reconstruction can reduce the risk of developing osteoarthritic knees. The goals of ACL reconstruction are to restore knee stability and reduce post-traumatic meniscal tears and cartilage degradation. A chronic ACL insufficiency frequently results in medial meniscus (MM) injury at the posterior segment. How ACL reconstruction can reduce the deformation of the MM posterior segment remains unclear. In this study, we evaluated the form of the MM posterior segment and anterior tibial translation before and after ACL reconstruction using open magnetic resonance imaging (MRI).

METHODS

Seventeen patients who underwent ACL reconstructions without MM injuries were included in this study. MM deformation was evaluated using open MRI before surgery and 3 months after surgery. We measured medial meniscal length (MML), medial meniscal height (MMH), medial meniscal posterior body width (MPBW), MM-femoral condyle contact width (M-FCW) and posterior tibiofemoral distance (PTFD) at knee flexion angles of 10° and 90°.

RESULTS

There were no significant pre- and postoperative differences during a flexion angle of 10°. At a flexion angle of 90°, MML decreased from 43.7 ± 4.5 to 41.4 ± 4.5 mm (P < 0.001), MMH from 7.5 ± 1.4 to 6.9 ± 1.4 mm (P = 0.006), MPBW from 13.1 ± 2.0 to 12.2 ± 1.9 mm (P < 0.001) and M-FCW from 10.0 ± 1.5 to 8.5 ± 1.5 mm (P < 0.001) after ACL reconstruction. The PTFD increased from 2.1 ± 2.8 to 2.7 ± 2.4 mm after ACL reconstruction (P = 0.015).

CONCLUSIONS

ACL reconstruction affects the contact pattern between the MM posterior segment and medial femoral condyle and can reduce the deformation of the MM posterior segment in the knee-flexed position by reducing abnormal anterior tibial translation. It possibly prevents secondary injury to the MM posterior segment and cartilage that progresses to knee osteoarthritis.

LEVEL OF EVIDENCE

IV.

Medial meniscus extrusion correlates with disease duration of the sudden symptomatic medial meniscus posterior root tear

INTRODUCTION

Medial meniscus posterior root tear (MMPRT) leads to abnormal biomechanics of the knee by inducing the medial meniscus extrusion (MME). However, a time-dependent increase of the MME is not fully elucidated in patients suffering from the acute MMPRT. The aim of this study was to investigate the relationships among disease duration of the MMPRT and severity of the MME. We hypothesized that MME measurement correlates with disease duration after a sudden onset of the minor traumatic MMPRT during the short-term follow-up period.

MATERIALS AND METHODS

Forty-six patients who had an accurate episode of the posteromedial painful popping were investigated. All the patients were diagnosed having a symptomatic MMPRT with magnetic resonance imaging (MRI) examinations. Absolute MME was measured using MRI scans within 12 months after painful popping events. A correlation coefficient between duration from injury to MRI examination and absolute MME was evaluated.

RESULTS

Mean absolute MME was 4.5±1.6mm (range, 1.1-8.8mm) on MRI measurements. A good correlation was observed between MME measurement and duration from injury to MRI examination (R²=0.612). The best-fit equation for predicting each value was: MME=0.014×disease duration+3.288mm.

DISCUSSION

This study demonstrated that absolute MME increases progressively within the short duration after the onset of symptomatic MMPRT. Our results suggest that preoperative MME assessment may be important in determining disease duration and treatment strategy of the MMPRT.

LEVEL OF EVIDENCE

Retrospective cohort study level IV.

Meniscal Extrusion Progresses Shortly after the Medial Meniscus Posterior Root Tear

Purpose

Medial meniscus posterior root tears (MMPRT) induce medial meniscus extrusion (MME). However, the time-dependent extent of MME in patients suffering from the MMPRT remains unclear. This study evaluated the extent of MME after painful popping events that occurred at the onset of the MMPRT.

Materials and Methods

Thirty-five patients who had an episode of posteromedial painful popping were investigated. All the patients were diagnosed as having an MMPRT by magnetic resonance imaging (MRI) within 12 months after painful popping. Medial meniscus body width (MMBW), absolute MME, and relative MME (100×absolute MME/MMBW) were assessed among three groups divided according to the time after painful popping events: early period (<1 month), subacute period (1–3 months), and chronic period (4–12 months).

Results

In the early period, absolute and relative MMEs were 3.0 mm and 32.7%, respectively. Absolute MME increased up to 4.2 mm and 5.8 mm during the subacute and chronic periods, respectively. Relative MME also progressed to 49.2% and 60.3% in the subacute and chronic periods, respectively.

Conclusions

This study demonstrated that absolute and relative MMEs increased progressively within the short period after the onset of symptomatic MMPRT. Our results suggest that early diagnosis of an MMPRT may be important to prevent progression of MME following the MMPRT.

Location of the tibial tunnel aperture affects extrusion of the lateral meniscus following reconstruction of the anterior cruciate ligament

The anterior root of the lateral meniscus provides functional stability to the meniscus. In this study, we evaluated the relationship between the position of the tibial tunnel and extrusion of the lateral meniscus after anterior cruciate ligament reconstruction, where extrusion provides a proxy measure of injury to the anterior root. The relationship between extrusion and tibial tunnel location was retrospectively evaluated from computed tomography and magnetic resonance images of 26 reconstructed knees, contributed by 25 patients aged 17-31 years. A measurement grid was used to localize the position of the tibial tunnel based on anatomical landmarks identified from the three-dimensional reconstruction of axial computed tomography images of the tibial plateaus. The reference point-to-tibial tunnel distance (mm) was defined as the distance from the midpoint of the lateral edge of the grid to the posterolateral aspect of the tunnel aperture. The optimal cutoff of this distance to minimize post-operative extrusion was identified using receiver operating curve analysis. Extrusion of the lateral meniscus was positively correlated to the reference point-to-tibial tunnel distance (r ²  = 0.64; p < 0.001), with a cutoff distance of 5 mm having a sensitivity to extrusion of 83% and specificity of 93%. The mean extrusion for a distance >5 mm was 0.40 ± 0.43 mm, compared to 1.40 ± 0.51 mm for a distance ≤5 mm (p < 0.001). Therefore, a posterolateral location of the tibial tunnel aperture within the footprint of the anterior cruciate ligament decreases the reference point-to-tibial tunnel distance and increases extrusion of the lateral meniscus post-reconstruction. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1625-1633, 2017.

A giraffe neck sign of the medial meniscus: A characteristic finding of the medial meniscus posterior root tear on magnetic resonance imaging

BACKGROUND

The posterior root ligament of the medial meniscus (MM) has a critical role in regulating the MM movement. An accurate diagnosis of the MM posterior root tear (MMPRT) using magnetic resonance imaging (MRI) is important for preventing sequential osteoarthritis following the MMPRT. However, diagnosis of the MMPRT is relatively difficult even after using several characteristic MRI findings. The aim of this study was to identify a useful meniscal body sign of the MMPRT for improving diagnostic MRI reading.

METHODS

Eighty-five patients who underwent surgical treatments for the MMPRT (39 knees) and other types of MM tears (49 knees) were included. The presence of characteristic MRI findings such as cleft sign, ghost sign, radial tear sign, medial extrusion sign, and new meniscal body shape-oriented "giraffe neck sign" was evaluated in 120 MRI examinations.

RESULTS

Giraffe neck signs were observed in 81.7% of the MMPRTs and in 3.3% of other MM tears. Cleft, ghost, and radial tear signs were highly positive in the MMPRTs compared with other MM tears. Medial extrusion signs were frequently observed in both groups. Coexistence rates of any 2 MRI signs, except for medial extrusion sign, were 91.7% in the MMPRT group and 5% in other MM tears.

CONCLUSIONS

This study demonstrated that a new characteristic MRI finding "giraffe neck sign" was observed in 81.7% of the MMPRT. Our results suggest that the combination of giraffe neck, cleft, ghost, and radial tear signs may be important for an accurate diagnostic MRI reading of the MMPRT.

Long-term assessment of meniscal extrusion after meniscal repair

BACKGROUND

Arthroscopic meniscal repair limits the medium-term risk of radiological osteoarthritis. Magnetic resonance imaging (MRI) cannot provide an accurate assessment of meniscal healing but may show harbingers of osteoarthritis such as meniscal extrusion. The objective of this study was to assess long-term meniscal extrusion after meniscal repair.

HYPOTHESIS

Arthroscopic meniscal suture is not followed by meniscal extrusion and can, therefore, provide good knee function in the long-term.

METHODS

Consecutive patients who underwent arthroscopic meniscal suture on a stable or stabilised knee were included retrospectively. MRI was performed to measure absolute meniscal extrusion (AME), relative meniscal extrusion (RME), anterior sagittal extrusion (ASE), posterior sagittal extrusion (PSE), coronal cartilage coverage index (cCCI), and sagittal cartilage coverage index (sCCI).

RESULTS

After a mean follow-up of 8.8±0.87 years, there was no evidence of meniscal extrusion in these patients with stable or stabilised knees: AME, 1.7±1.03 and 2.3±0.93mm, RME, 17±0.10% and 28±0.12%, ASE, 2.52±1.43 and 1.71±2.42mm, PSE, 0.29±3.49 and 0.22±2.35mm, cCCI, 23±0.08% and 20±0.09%, and sCCI, 49±0,10% and 53±0.09%.

CONCLUSION

In the long-term after meniscal repair, osteoarthritis is limited and meniscal function seems preserved.

LEVEL OF EVIDENCE

IV, retrospective study.

Functional knee assessment with advanced imaging

The purpose of anterior cruciate ligament (ACL) reconstruction is to restore the native stability of the knee joint and to prevent further injury to meniscus and cartilage, yet studies have suggested that joint laxity remains prevalent in varying degrees after ACL reconstruction. Imaging can provide measurements of translational and rotational motions of the tibiofemoral joint that may be too small to detect in routine physical examinations. Various imaging modalities, including fluoroscopy, computed tomography (CT), and magnetic resonance imaging (MRI), have emerged as powerful methods in measuring the minute details involved in joint biomechanics. While each technique has its own strengths and limitations, they have all enhanced our understanding of the knee joint under various stresses and movements. Acquiring the knowledge of the complex and dynamic motions of the knee after surgery would help lead to improved surgical techniques and better patient outcomes.

The anterior cruciate ligament-lateral meniscus complex: A histological study

The anterior root of the lateral meniscus (LM) dives underneath the tibial attachment of the anterior cruciate ligament (ACL). Although the distinct role of meniscal attachments has been investigated, the relationship between the LM anterior insertion (LMAI) and ACL tibial insertion (ACLTI) remains unclear. This study histologically analyzed the LMAI and ACLTI. Samples were divided into four regions in an anterior-to-posterior direction. Histological measurements of these insertion sites were performed using safranin O-stained coronal sections. Distribution and signal densities of type I and II collagen were quantified. The ACLTI and LMAI formed the ACL-LM complex via fiber connections. The anterior part of the ACLTI had a widespread attachment composed of dense fibers. Attachment fibers of the LMAI became dense and wide gradually at the middle-to-posterior region. The ACL-LM transition zone (ALTZ) was observed between the LMAI and the lateral border of the ACLTI at the middle part of the ACL tibial footprint. Type II collagen density of the LMAI was higher than that of the ACLTI and ALTZ. Our results can help create an accurate tibial bone tunnel within the dense ACL attachment during ACL reconstruction surgery.

The figure-of-nine leg position for anatomic anterior cruciate ligament reconstruction

Anatomic double-bundle anterior cruciate ligament (ACL) reconstruction can restore the function and kinematics of the knee in ACL-deficient patients. Several outside-in drilling systems for accurate femoral tunnel creations have been developed. However, the femoral tunnel creation at the lower position of the intercondylar notch can be difficult in a usual leg position with the knee flexed at 90° without varus stress. This technical note describes that the figure-of-nine leg position provides a better arthroscopic view to safely clean up the ACL femoral footprint located at the lower area of the lateral intercondylar wall. This position is useful to create the optimal femoral tunnels using the outside-in drilling technique, without damaging the lateral meniscus posterior root, lateral tibial eminence, and supplemental fibers that bridge the gap between the lateral meniscus and the ACL tibial insertion.

Postoperative change in the length and extrusion of the medial meniscus after anterior cruciate ligament reconstruction

PURPOSE

The medial meniscus is a secondary stabilizer of anterior tibial translation in anterior cruciate ligament (ACL)-deficient knees. ACL reconstruction effectively restores an increased anterior tibial translation in the ACL-deficient knee. However, knee osteoarthritis sometimes develops in ACL-reconstructed patients during a long-term follow-up period. We hypothesized that the medial meniscal position would be different between the ACL-deficient and reconstructed knees. The aim of this study was to investigate pre-operative and postoperative location of the medial meniscus in patients who underwent ACL reconstruction.

METHODS

ACL-reconstructed knees (28 knees) and normal knees (27 knees) were investigated. Medial tibial plateau length (MTPL) and medial tibial plateau width (MTPW) were determined using radiographic images. Magnetic resonance imaging (MRI)-based medial meniscal length (MML), medial meniscal width (MMW), and medial meniscal extrusion (MME) were measured. Postoperative change in the MML, MMW, and MME were evaluated and compared with those in normal knees.

RESULTS

No significant differences between the ACL-deficient (pre-operative) and normal groups were noted. The ACL-reconstructed (postoperative) group showed an increase in the MML, in the percentage of the MML (%MML = 100 MML/MTPL), and in the MME. Significant differences between postoperative and normal groups were observed in the MML, %MML, and MME. MMW and MMW percentage (100 MMW/MTPW) were similar in all groups.

CONCLUSIONS

The anteroposterior length and radial extrusion of the medial meniscus increased after ACL reconstruction. Transposition of the medial meniscus may be a possible cause of developing further degenerative knee joint disorders after ACL reconstruction.

Acute and chronic menisco-capsular separation in the young athlete: diagnosis, treatment and results in thirty seven consecutive patients

PURPOSE

Menisco-capsular separation (MCS) is an avulsion type of injury of the medial and/or lateral meniscus and is defined as detachment of the meniscus from its capsular attachment. The aims of this study were to show the results of arthroscopic all-inside menisco-capsular repair in a large number of consecutive patients with acute or chronic MCS, emphasise the advantages of this safe treatment option and stress the superiority of the treatment on the basis of thorough physical examination of the knee joint over magnetic resonance imaging (MRI) diagnosis in MCS.

METHODS

We evaluated data of patients treated between October 2011 and July 2012. Inclusion and exclusion criteria were defined and demographic variables evaluated. All patients were examined physically and with MRI. Knee arthroscopy was performed and the MCS repaired through all-inside menisco-capsular repair. Postoperative treatment was standardised. Patients were followed up for at least 24 weeks.

RESULTS

Thirty-seven athletes (12 women, 25 men) were evaluated. Only in six patients was MCS detected on MRI. In all patients, MCS was diagnosed via physical examination. Arthroscopic treatment led to significant (p < 0.01) improvement. There were no complications reported postoperatively.

CONCLUSION

Isolated MCS is not as rare a meniscus pathology after trauma in young athletes as could be expected after reviewing current literature. It is occult on MRI scans in most of the cases and should therefor be taken into consideration in patients with acute or chronic tenderness at the level of the joint line and negative MRI scans. Thorough physical examination has higher diagnostic value than MRI alone, as shown in this study. Treatment of MCS using all-inside nonabsorbable sutures, as described in this study using Ultra FasT Fix®, is effective if performed by an experienced surgeon.