Repair of radial tears and posterior horn detachments of the lateral meniscus: minimum 2-year follow-up

Meniscal Radial Tears Repaired With All-Inside and Inside-Out Techniques Result in Improved Clinical Outcome Scores, but Inside-Out Repairs May Be Associated With Higher Failure Rates Clinically and on Second-Look Arthroscopy: A Systematic Review

PURPOSE

To compare patient-reported outcomes (PROs), failure, and healing rates after all-inside (AI) repair versus inside-out (IO) repair for the treatment of meniscal radial tears.

METHODS

A literature search was performed according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using the Scopus, PubMed, and Embase computerized databases. Level of Evidence I through IV human clinical studies evaluating PROs and/or the incidence of failure and healing after AI versus IO repairs for meniscal radial tears were included. Clinical failure was defined by the presence of joint-line tenderness; a positive McMurray test; and mechanical symptoms, such as locking, catching, or giving way. Study quality was assessed using the Methodological Index for Non-Randomized Studies criteria and the Modified Coleman Methodology Score.

RESULTS

Ten studies published from 2008 to 2023 comprising 205 patients were identified, including 142 patients who underwent AI repair and 63 patients who underwent IO repair for radial meniscus tears. Postoperative Lysholm and Tegner scores ranged from 90.8 to 95.6 and 5.7 to 8.2, respectively, in the AI repair group, compared with 86.9 to 94.2 and 6 to 7.5, respectively, in the IO repair group. All patients exceeded published values for minimal clinically important difference for the Lysholm score. Clinical failure ranged from 0% to 40% in the AI group and 0% to 62.5% in the IO group. Healing assessments on second-look arthroscopy revealed failure rates ranging from 0% to 13.3% in the AI group and 0% to 39% in the IO group. Complete and partial healing ranged from 28.6% to 92.3% in the AI group and from 25% to 70% in the IO group. Chondral damage on second-look arthroscopy ranged from 0% to 95% in the IO group and 0% to 57.7% in the AI group. Postoperative complications ranged from 0% to 2% within the AI group, whereas no complications were reported in the IO group. No implant-related complications were reported in any study group.

CONCLUSIONS

Both all-inside and inside-out repairs for meniscal radial tears demonstrated improved PROs; however, current literature suggests that the IO technique may have higher failure rates both clinically and on second-look arthroscopy.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.

Stener-like lesion of the lateral meniscus in the setting of a multiligamentous knee injury: A case report

Traumatic dislocations of the knee can result in significant soft tissue damage including multiligamentous and meniscal knee injury. When a meniscal tear involves the posterior horn, the meniscus loses one of its attachments to the tibia and can become extruded from the joint. Stener-like lesions of the knee have been reported throughout the literature; however, they have been exclusively described as a distal tear of the medial collateral ligament (MCL) lying superficial to the pes anserine tendon which prevents anatomic healing. The purpose of this report is to present a previously unreported unique variant of a lateral meniscus tear in the setting of a MLKI. In this case presentation, the lateral meniscus became extruded superficial to the intact lateral collateral ligament (LCL) resulting in a Stener-like lesion. Corrective recognition of lesions like these and timely surgical intervention is recommended to restore native anatomy and prevent chronic pain, instability, and premature degenerative disease. Level IV, Case report.

Steep Posterior Tibial Slope and Excessive Anterior Tibial Translation Are Associated With Increased Sagittal Meniscal Extrusion After Posterior Lateral Meniscus Root Repair Combined With Anterior Cruciate Ligament Reconstruction

Purpose

To (1) evaluate the clinical and radiographic outcomes of patients with primary anterior cruciate ligament reconstruction (ACLR) with type II posterior lateral meniscus root tear (PLMRT) repair and (2) identify whether increased anterior tibial subluxation of the lateral compartment (ATSLC) and steeper posterior tibial slope (PTS) are associated with sagittal lateral meniscal extrusion (LME).

Methods

Patients who underwent primary anatomic ACLR with concomitant type II PLMRTs using the all-inside side-to-side repair technique between November 2014 and September 2020 were identified. To be included, patients must have had a minimum of 2 years follow-up. All patients, including those with ATSLC and PTS and sagittal and coronal LME, were retrospectively reviewed clinically and radiologically. The patients were divided into 2 subgroups according to the occurrence of sagittal LME.

Results

Forty patients were included in this study with a mean follow-up of 44 months (range, 24-94 months). In general, the postoperative parameters, including grade of pivot shift, side-to-side difference, ATSLC, Lysholm score, and International Knee Documentation Committee (IKDC) score, were significantly improved compared with the preoperative ones. However, postoperative sagittal LME was detected to be significantly larger than the preoperative one. Minimal clinically important difference (MCID) analysis for postoperative outcomes showed that the rate of patients who achieved MCID thresholds was 100% for Lysholm, 95% for IKDC, 42.50% for coronal LME, 62.50% for sagittal LME, 40% for ATSLC, and 100% for side-to-side difference. Further comparisons, where patients were divided into 2 subgroups according to the occurrence of sagittal LME, showed significant differences in PTS, ATSLC, and coronal LME.

Conclusions

Clinical outcomes after type II PLMRT repair with primary ACLR were significantly improved, except for LME, at the 2-year postoperative follow-up. After repair of type II PLMRT injuries, the presence of sagittal LME was associated with increased PTS and ATSLC.

Level of Evidence

Level III, retrospective cohort study.

Outcomes of Lateral Meniscal Oblique Radial Tear Repair Compared With Intact Meniscus After ACL Reconstruction: A Cohort Study

Background

Recently, the posterior horn lateral meniscal oblique radial tear (LMORT) was identified in 12% of acute anterior cruciate ligament (ACL) injuries. However, patient-reported outcomes for repair of this relatively common tear have not been reported.

Purpose

To determine the minimum 2-year functional outcomes after LMORT repair at the time of ACL reconstruction (ACLR) compared to a matched cohort of patients who underwent isolated ACLR (iACLR).

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 100 patients (mean age at surgery, 21 years; range, 13-45 years) who underwent primary ACLR between 2010 and 2018. The mean follow-up period was 4.1 ± 2.0 years (range, 2.0-9.2 years). A total of 50 patients with surgically repaired LMORT type 3 or type 4 lesions, defined as partial or complete tears >10 mm from the root (LMORT group) were matched 1:1 based on age, date of surgery, and graft choice with 50 patients who underwent iACLR (iACLR group). The postoperative outcomes were compared between groups using the International Knee Documentation Committee subjective score (sIKDC) and the Tegner activity scale. An updated medical history was obtained via the electronic medical record to determine any subsequent complications and reoperations.

Results

There was 1 ACL graft failure in each group as well as 5 (10%) reoperations per group. None of the patients in the LMORT group necessitated a lateral meniscal revision repair or partial meniscectomy. The LMORT and iACLR groups reported comparable sIKDC scores (92.5 ± 6.8 vs 91.9 ± 8.2, respectively; P = .712) as well as Tegner scores (6.7 ± 1.8 vs 6.6 ± 1.8, respectively; P = .910) at final follow-up. No failures of the LMORT repairs were reported.

Conclusion

The study findings demonstrated that reoperations, graft failure rates, patient-reported outcomes, and patient activity levels at ≥2 years after type 3 and 4 LMORT repairs at the time of ACLR compared favorably with those of a matched cohort of patients who underwent iACLR with intact meniscus.

Concurrent Repair of Medial Meniscal Ramp Lesions and Lateral Meniscus Root Tears in Patients Undergoing Anterior Cruciate Ligament Reconstruction: The "New Terrible Triad"

Recent studies have suggested that up to 8% of patients with anterior cruciate ligament (ACL) tears can present with a combined medial meniscal ramp lesion (MMRL) and lateral meniscus root tear (LMRT). MMRLs and LMRTs often are missed preoperatively and can increase the risk of ACL graft failure if left untreated. Given the potential synergistic biomechanical consequences and challenging repair techniques used for treatment, our group commonly refers to this presentation (MMRL-LMRT-ACL) as the "new terrible triad" of ACL pathology. This Technical Note aims to describe a systematic approach for arthroscopic assessment and our preferred inside-out and transtibial pull-out repair techniques to efficiently diagnose and treat a combined MMRL and LMRT at the time of ACL reconstruction surgery.

Repair of meniscus root tear - Is there a difference between medial meniscus root repair and lateral meniscus root repair? A systematic review and meta-analysis

PURPOSE

Complete meniscus root tear is associated with meniscus extrusion; this causes a loss of meniscus function and accelerated osteoarthritis of the knee. Existing small-scale retrospective case-control studies suggested that the outcomes were different between medial and lateral meniscus root repair. This meta-analysis aims to study whether such discrepancies exist via a systematic review of the available evidence in the literature.

METHODS

Studies evaluating the outcomes of surgical repair of posterior meniscus root tears, with reassessment MRI or second-look arthroscopy, were identified through a systematic search of PubMed, Embase, and Cochrane Library. The degree of meniscus extrusion, healing status of the repaired meniscus root, and functional outcome scores after repair were the outcomes of interest.

RESULTS

Among the 732 studies identified, 20 studies were included in this systematic review. 624 knees and 122 knees underwent MMPRT and LMPRT repair, respectively. The amount of meniscus extrusion following MMPRT repair was 3.8 ± 1.7 mm, which was significantly larger than the 0.9 ± 1.2 mm observed after LMPRT repair (p < 0.001). Significantly better healing outcomes were observed on reassessment MRI after LMPRT repair (p < 0.001). The postoperative Lysholm score and IKDC score was also significantly better after LMPRT than MMPRT repair (p < 0.001).

CONCLUSIONS

LMPRT repairs resulted in significantly less meniscus extrusion, substantially better healing outcomes on MRI, and superior Lysholm/IKDC scores, when compared to MMPRT repair. This is the first meta-analysis we are aware of that systematically reviews the differences in the clinical, radiographic, and arthroscopic results of MMPRT and LMPRT repair.

Patients with meniscus posterolateral root tears repair during ACL reconstruction achieve comparable post-operative outcome than patients with isolated ACL reconstruction

PURPOSE

Lateral posterior meniscal root tear (LPMRT) repair, at the time of anterior cruciate ligament (ACL) reconstruction are increasingly being performed. The aim of this study was to compare the clinical and functional outcomes, as well as the complication rates at a minimum of 2 years follow-up, between an isolated ACL reconstruction group with intact menisci and a combined ACL reconstruction and LPMRT repair group.

METHODS

All patients who underwent combined ACL reconstruction and LPMRT repair between 2016 and 2020 were included in the study. They were matched with an isolated ACL reconstruction group with intact menisci based on age, gender and the pre-injury IKDC score. The KOOS, ACLRSI Tegner-Lysholm score and the TELOS-test were collected pre- and postoperatively; complications (re-rupture, recurrence or persistence of a high grade pivot shift, new meniscal injury) were recorded. All LPMRTs were repaired using transtibial pull-out technique.

RESULTS

After matching, 100 patients were included in this study (mean age 29.6 ± 1.0 years and mean follow-up 42.9 ± 7.3 months): 50 patients in the isolated ACL reconstruction group with intact menisci (group A) and 50 in the combined ACL reconstruction and LPMRT repair group (group B). Preoperatively, patients in group B had significant lower KOOS scores (Global 55.9 ± 2.9 vs. 64.6 ± 2.3, p = 0.02), but similar ACLRSI, TEGNER and TELOS scores. At the last follow-up, all functional scores had improved, and no significant difference between the two groups on any score was observed. There was also no difference in terms of complications rates.

CONCLUSION

At a minimum of 2 years follow-up (mean follow-up 42.9 months), LPMRT repair during ACL reconstruction has no significant difference in terms of post-operative functional outcomes compared to the isolated ACL reconstruction group.

LEVEL OF EVIDENCE

Level III.

Low reoperation rate following lateral meniscus root repair: clinical outcomes at 2 years follow-up

PURPOSE

The aim of this study was to review the outcomes of lateral meniscus posterior root tears repair at the time of ACL reconstruction at a minimum 2-year follow-up.

METHODS

Between March 2015 and August 2018, 2017 patients underwent primary ACL reconstruction and were considered for study eligibility. Lateral meniscus posterior root tears were identified arthroscopically, and repair was performed with a transtibial pull-out suture technique or a side-to-side suture technique. Clinical outcomes were recorded at the time of physical examination. At the end of the study period, patients were contacted to determine whether they had required reoperation.

RESULTS

Lateral meniscus posterior root tears were identified in 153 out of the 2,017 primary ACL reconstructions (7.6%). Ninety-nine patients were included for analysis: 23 transtibial pull-out sutures and 76 side-to-side repairs. At a mean follow-up of 42 ± 10 months, one patient (1%) had undergone reoperation for failure of the side-to-side repair. There were 11 reoperations in 10 patients (10.1%), including 6 cyclops syndrome, 1 graft rupture, 1 tibial bone cyst, 1 medial and 1 lateral meniscus repair failure, and 1 arthrolysis. Postoperatively, ninety (90.9%) patients were graded A for the IKDC objective score and 9 (9.1%) patients were graded B, with an IKDC subjective score of 86.9 ± 7.6, a Lysholm score of 90.7 ± 6.7 and a median Tegner Activity Scale of 6 (3-9). All of their objective and subjective evaluations improved after surgery (p < 0.001) except for the Tegner Activity Scale. Ten patients underwent second look arthroscopy (10.1%), lateral meniscus healing was observed in 9 out of 10 patients (90%).

CONCLUSION

This study demonstrated that lateral meniscus posterior root tear repair is a safe procedure with a very low reoperation rate at a minimum follow-up of 2 years.

LEVEL OF EVIDENCE

IV.

In situ repair of segmental loss posterior lateral meniscal root tears outperforms meniscofemoral ligament imbrication in the ACL reconstructed knee

PURPOSE

The purpose of this study was to compare the biomechanical effect of in-situ repair of posterior lateral meniscal root (PLMR) tear with segmental meniscal loss, with and without meniscofemoral ligament (MFL) imbrication, on anterior cruciate ligament (ACL) graft force and knee joint kinematics.

METHODS

Ten fresh-frozen cadaveric knee specimens underwent kinematic evaluation in five states: 1) Native, 2) ACLR, 3) Segmental PLMR loss, 4) In-situ PLMR repair, and 5) MFL augmentation. Kinematic evaluation consisted of five tests, each performed at full extension and at 30° of flexion: 1) Anterior drawer, 2) Internal Rotation, 3) External Rotation, 4) Varus, and 5) Valgus. Additionally, a simulated pivot shift test was performed. Knee kinematics and ACL graft force were measured.

RESULTS

PLMR tear did not significantly increase ACL graft force in any test. However, PLMR repair significantly reduced ACL graft force compared to the ACLR alone (over constraint -26.6 N, p = 0.001). PLMR tear significantly increased ATT during the pivot shift test (+ 2.7 mm, p = 0.0001), and PLMR repair restored native laxity. MFL augmentation did not improve the mechanics.

CONCLUSIONS

In-situ PLMR repair eliminated pivot shift laxity through ATT and reduced force on the ACL graft, indicating that this procedure may be ACL graft-protective. MFL augmentation was not shown to have any effect on graft force or knee kinematics and untreated PLMR tears may place an ACL graft at higher risk. This study suggests concomitant repair to minimize additional forces on the ACL graft.

Combined Repair of Medial Meniscal Ramp Lesions and Posterior Root Tears of the Lateral Meniscus During Anterior Cruciate Ligament Reconstruction: A Case Report

CASE

This case report describes the clinical outcomes for 2 patients who underwent a primary or revision anterior cruciate ligament (ACL) reconstruction with a combined inside-out and transtibial pullout repair for a medial meniscal ramp lesion (MMRL) and a lateral meniscus root tear (LMRT), respectively. Promising short-term outcomes were seen at the one-year follow-up for both patients.

CONCLUSIONS

Utilization of these repair techniques can successfully treat a combined MMRL and LMRT injury at the time of primary or revision ACL reconstruction.

Transtibial Pullout Repair of Lateral Meniscus Posterior Root Tear with Tissue Loss: A Case with Anterior Cruciate Ligament Injury and Medial Meniscus Tear

Lateral meniscus (LM) posterior root tear (LMPRT) is mainly caused by trauma, especially trauma associated with anterior cruciate ligament (ACL) injuries. Although a transtibial pullout repair or a side-to-side repair is commonly performed for LMPRT, to the best of our knowledge, there is no clinical report of LMPRT with tissue loss using the pullout technique. Thus, the purpose of this report was to describe a clinical, radiographic, and arthroscopic outcome after pullout repair for a case of LMPRT with a large defect with a chronic ACL tear and complex medial meniscus (MM) tears. A 31-year-old man complained of knee pain and restricted range of motion after twisting his knee when he stepped on an iron pipe. The patient had a football-related injury to his right knee 14 years before presentation, and since then, the patient's knee has given out more than 10 times but was left unassessed. Magnetic resonance imaging showed LMPRT with tissue loss, ACL tears, and complex MM tears. Transtibial pullout repair of the LMPRT with ACL reconstruction and MM repairs were performed. Following the pullout repair of the LMPRT, an approximately 6 mm gap remained between the LM posterior root and root insertion. However, magnetic resonance imaging and second-look arthroscopy at 1 year postoperatively revealed meniscal healing, gap filling with some regeneration tissue, of the LM posterior root. Furthermore, the lateral meniscus extrusion in the coronal plane improved from 3.1 mm (preoperative) to 1.6 mm (1 year postoperatively). Transtibial pullout repair with the remaining gap could be a viable treatment option for LMPRT with tissue loss, combined with ACL reconstruction.

Shared ACL Bone Tunnel Technique for Repair of Lateral Meniscus Posterior Root Tears Combined With ACL Reconstruction

Background

Independent transtibial pullout repair is a common surgical technique for repairing lateral meniscus posterior root tears (LMPRTs). The shared anterior cruciate ligament (ACL) bone tunnel technique is an alternative technique for LMPRT repair combined with ACL reconstruction (ACLR) to avoid the establishment of additional bone tunnels.

Purpose

To compare the clinical outcomes of the shared ACL bone tunnel versus the independent transtibial pullout techniques for LMPRT repair combined with ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

Between March 2014 and February 2018, a total of 48 patients were diagnosed with ACL injury with concomitant LMPRT; 22 patients underwent independent transtibial pullout repair (group T), and 26 patients underwent the shared ACL bone tunnel technique (group S). At a follow-up of >2 years, we compared knee functional recovery using the Lysholm, Tegner, and International Knee Documentation Committee scores and the pivot-shift test. Lateral meniscal extrusion, and cartilage degeneration on magnetic resonance imaging (MRI) scans were also compared. The healing status of the lateral meniscus posterior root was compared using second-look arthroscopy and MRI.

Results

The duration of surgery was significantly shorter in group S compared with group T (98.3 ± 11.1 vs 127.9 ± 17.5 min; P = .001). At final follow-up, there were no significant differences between the 2 groups in knee functional scores, pivot shift, or grade of cartilage degeneration. Lateral meniscal extrusion was decreased in group S compared with group T (2.41 ± 0.61 vs 1.59 ± 1.35 mm; P = .014). Second-look arthroscopy revealed stable healing in 16 of 18 patients (88.9%) in group S and 10 of 15 patients (66.7%) in group T (P = .38).

Conclusion

Both the shared ACL bone tunnel and the independent transtibial pullout techniques led to satisfactory clinical outcomes. The shared ACL bone tunnel technique is the simpler of the 2 procedures for combined LMPRT repair with ACLR.

Epidemiology of Combined Injuries of the Secondary Stabilizers in ACL-Deficient Knees: Medial Meniscal Ramp Lesion, Lateral Meniscus Root Tear, and ALL Tear: A Prospective Case Series of 602 Patients With ACL Tears From the SANTI Study Group

BACKGROUND

Medial meniscal ramp lesion (MMRL), lateral meniscus root tear (LMRT), and anterolateral ligament (ALL) tear are individual injuries that have been described in patients who have an anterior cruciate ligament (ACL) tear. However, the prevalence of these lesions and their combination has not been defined.

PURPOSES

To define the individual and combined prevalence of MMRL, LMRT, and ALL tears in a case series of patients undergoing ACL reconstruction and to identify the risk factors for combined injuries.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Patients aged >15 years undergoing primary ACL reconstruction between January 2019 and June 2021 were enrolled in the study. A preoperative ultrasound scan was performed to look for an ALL tear. The presence of MMRL and LMRT was determined during a standardized arthroscopy exploration. A multivariate logistic regression model was used to determine the individual effect of patient variables on the risk of associated single, dual, triad, or tetrad injuries (MMRL, LMRT, ALL, ACL), represented by an adjusted odds ratio.

RESULTS

The case series consisted of 602 patients who underwent primary ACL reconstruction. An isolated ACL injury was present in 147 patients (24%). A dual injury was detected in 34 patients (6%) who had ACL-MMRL, 16 (2.65%) who had ACL-LMRT, and 265 (44%) who had ACL-ALL. A triad injury was detected in 80 patients (13.28%) who had ACL-ALL-MMRL, 36 (6%) who had ACL-ALL-LMRT, and 3 (0.5%) who had ACL-MMRL-LMRT. A tetrad injury pattern was detected in 21 patients (3.5%). Multivariate analysis showed that the occurrence of tetrad injury was significantly lower in older patients (adjusted odds ratio by year, 0.93 [95% CI, 0.88-0.99]; P = .028). Identifying LMRT increased the likelihood of finding MMRL-ALL injuries by 2.11 times (95% CI, 1.09-3.12; P = .031).

CONCLUSION

Isolated ACL tear is less common than combined injuries, which are quite frequent. Younger age is a risk factor for combined injuries. The search for damaged secondary stabilizers of the knee must be meticulous and systematic, especially when 1 injured structure has already been diagnosed.

Repairing Complete Radial Tears of the Lateral Meniscus: Arthroscopic All-Inside Double Vertical Cross-Suture Technique Is Effective and Safe With 2-Year Minimum Follow-Up

PURPOSE

To assess the failure rate and clinical outcomes of the all-inside, double-vertical, cross-suture technique in repairing complete radial tears of the lateral meniscus.

METHOD

We retrospectively reviewed records of patients with this injury on whom the present technique was employed at our institution between 2011 and 2018, with at least 24 months of follow-up. Six months postoperatively, the meniscus healing and extrusion status were evaluated through magnetic resonance imaging. Preoperative and postoperative knee function, measured through IKDC, Lysholm knee, and Tegner activity scale scores, were compared.

RESULTS

In total, 27 patients underwent the procedure. The preoperative mean (standard deviation) IKDC score, Lysholm knee score, and Tegner activity scale scores were 53.4 ± 5.3, 63.2 ± 9.3, and 4 ± .7, respectively. At the last follow-up (≥24 months postoperatively), these scores increased to 92.1 ± 2.6, 90.8 ± 4.2, and 6.1 ± 1.3, respectively (all P < .05). Complete healing of the meniscus was observed in 23 patients, and 4 patients had meniscus retear or nonhealing. The overall retear or nonhealing rate was 14.8%. Healing rates between those with isolated radial tears (87.5%) and those with combined anterior cruciate ligament rupture (84.2%; P = .826) were comparable. No difference was observed in the progression of coronal and sagittal meniscus extrusion (P = .133 and .797, respectively).

CONCLUSION

In patients with complete radial tears of the lateral meniscus, the arthroscopic all-inside double vertical cross-suture repair technique resulted in an 85.2% healing rate, improvements in functional outcomes and activity levels, and no identifiable progression of meniscus extrusion. The all-inside double vertical cross-suture technique is effective and safe for the repair of radial tears of the meniscus.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Transtibial pull-out repair of lateral meniscus posterior root is beneficial for graft maturation after anterior cruciate ligament reconstruction: a retrospective study

PURPOSE

To determine the repair of LMPR lesions would improve the ACL graft maturation.

METHOD

A total of 49 patients underwent ACL reconstruction were included in this study. Patients were furtherly sub-grouped according to the status of LMPR: intact (17), repair (16) and resected (16). Assessments performed pre- and 2 years post-operatively included patients-reported scores and arthrometer side-to-side difference. Magnetic resonance imaging was used 2 years after the surgery to compare the lateral meniscal extrusion (LME), anterior tibial subluxation of the medial compartment (ATSMC), anterior tibial subluxation of the lateral compartment (ATSLC), the difference of ATSMC and ATSLC, and signal/noise quotient (SNQ) of ACL graft.

RESULTS

In LMPR resected group, it showed greater post-operative ATSMC-ATSLC difference when compared with pre-operatively (P = 0.006) and with the other 2 groups (intact: P = 0.031; repair: P = 0.048). SNQ of ACL graft was higher in LMPR resected group than those in LMPR intact (P = 0.004) and repair group (P = 0.002). The LMPR repair group showed significant reduction in LME post-operatively (P = 0.001). Post-operative measures on ATSLC-ATSMC difference (β = 0.304, P = 0.049) and LME (β = 0.492, P = 0.003) showed significant association with graft SNQ.

CONCLUSIONS

Transtibial repair of LMPR concomitant with ACL reconstruction restored translational stability, reduced meniscus extrusion, making it beneficial for ACL graft maturation.

Association of Postoperative Lateral Meniscal Extrusion With Cartilage Degeneration on Magnetic Resonance Imaging After Discoid Lateral Meniscus Reshaping Surgery

Background:

Although arthroscopic reshaping surgery for a discoid lateral meniscus (DLM) has good clinical results, it cannot completely prevent degeneration. The degree of DLM extrusion associated with degenerative changes is unclear.

Purpose/Hypothesis:

To measure meniscal extrusion preoperatively and postoperatively in patients who underwent DLM-reshaping surgery and examine factors associated with knee articular cartilage degeneration. It was hypothesized that meniscal extrusion existed preoperatively, progressed postoperatively, and was related to knee joint degeneration.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We retrospectively reviewed the medical records of patients who underwent DLM-reshaping surgery and attended ≥2 years of follow-up. Magnetic resonance imaging (MRI) was performed preoperatively and at 24 months postoperatively, and residual midbody meniscal extrusion was measured. Cartilage degeneration was detected when the Whole-Organ Magnetic Resonance Imaging Score (WORMS) of the lateral compartment was grade ≥3 at 2 years postoperatively. Factors associated with MRI cartilage degeneration were evaluated.

Results:

Included in this study were 48 knees in 39 patients; the mean patient age at the time of surgery was 12.0 years. The mean midbody meniscal extrusion significantly increased from 0.8 mm preoperatively to 1.6 mm at 24 months postoperatively ( P < .001). According to the WORMS cartilage score, 16 patients were categorized as having MRI cartilage degeneration. Multivariate logistic analysis showed that an inferior preoperative Lysholm score (odds ratio, 0.89; P = .024) and postoperative extrusion (odds ratio, 6.18; P = .010) significantly increased the risk of cartilage degeneration. The receiver operating characteristic curve showed that a residual meniscal extrusion of 2.0 mm was the cutoff value indicating cartilage degeneration (sensitivity, 87.5%; specificity, 78.1%).

Conclusion:

DLM extrusion significantly increased from 0.8 mm preoperatively to 1.6 mm at 2 years postoperatively. Postoperative extrusion and a lower preoperative Lysholm score were factors related to MRI cartilage degeneration postoperatively. A postoperative extrusion of 2.0 mm was the cutoff value for MRI cartilage degeneration.

Arthroscopic Repair of Posterior Root Tears of the Lateral Meniscus with All-Suture Anchor

Meniscus root tears are increasingly being recognized and treated because of improved awareness and diagnostics. These injuries commonly occur in combination with knee ligament injuries. Untreated posterior meniscus root teats have been demonstrated to increase contact pressure and decrease contact area, ultimately leading to unfavorable joint loading and development of early osteoarthritis. Posterior lateral meniscus root tears (PLMRTs) also have been reported to increase anterior tibial translation and pivot shift in anterior cruciate ligament-deficient knees. Therefore, it is crucial to repair meniscal root tears when possible to restore knee joint loading and kinematics. Several techniques for repair of the PLMRT have been described. In this Technical Note, we describe our preferred technique for repair of PLMRT using an all-suture anchor. This technique is reproducible, does not need a tunnel, mitigates bungee effect of transtibial technique, and the anchor can easily be inserted on the footprint without a need for a guide.

Large lateral tibial slope and lateral-to-medial slope difference are risk factors for poorer clinical outcomes after posterolateral meniscus root tear repair in anterior cruciate ligament reconstruction

BACKGROUND

Meniscus root tear is an uncommon but detrimental injury of the knee. Hoop stress is lost during meniscus root tear, which can lead to excessive tibiofemoral contact pressure and early development of osteoarthritis. Posterolateral meniscus root tears (PLRT) are more commonly associated with anterior cruciate ligament (ACL) tears. As the lateral compartment is less congruent than the medial compartment, it is more susceptible to a shearing force, which is increased in the ACL-deficient knee. In accordance with the compressive axial load, the increase in the tibial slope would generate a greater shearing force. The additional lateral compartment mobility caused by ACL tear should be reduced after ACL reconstruction (ACLR). However, there is a lack of evidence to conclude that ACLR can sufficiently limit the effect of large tibial slope (LTS) on the healing after PLRT repair. This study aimed to evaluate whether a steep LTS would be a risk factor for poorer clinical outcomes after PLRT repair concomitant with ACLR.

METHODS

In this retrospective study, a chart review was conducted to identify patients with concomitant unilateral primary ACLR and PLRT repair. Patients with a partial tear or healed tear were excluded. Postoperative MRI and clinical assessments were performed at a mean follow up of 35 months. MRI data was used to measure the LTS, medial tibial slope (MTS), coronal tibial slope (CTS), the lateral-to-medial slope difference (LTS-MTS) and meniscus healing and extrusion. Functional outcomes were evaluated by patient-reported outcomes (International Knee Documentation Committee [IKDC], Lysholm and Tegner scores) and KT-1000 arthrometer assessment. Interobserver reproducibility was assessed by two reviewers.

RESULTS

Twenty-five patients were identified for the analysis. Patients with larger LTS and larger LTS-MTS differences were shown to be correlated with poorer IKDC scores after surgery (R = -0.472, p = 0.017 and R = -0.429, p = 0.032, respectively). Herein, patients with LTS ≥ 6° or LTS-MTS ≥ 3° demonstrated poorer IKDC scores.

CONCLUSION

A large LTS (≥ 6°) and a large difference of LTS-MTS (≥ 3°) were shown to be risk factors for poorer functional and radiological outcomes for PLRT repair in patients after ACLR. Clinically, closer monitoring and a more stringent rehabilitation plan for patients with LTS ≥ 6° or LTS-MTS ≥ 3° would be recommended.

Outcomes of Combined Lateral Meniscus Posterior Root Repair and Anterior Cruciate Ligament Reconstruction

Background:

Lateral meniscus posterior root tears (LMPRTs) almost always occur in association with anterior cruciate ligament (ACL) tears. Their repair is advocated to restore the stabilizing and load-sharing functions of the meniscus.

Purpose:

To study the functional outcomes of combined arthroscopic repair of LMPRTs and ACL reconstruction (ACLR).

Study Design:

Case series; Level of evidence, 4.

Methods:

The authors evaluated patients who underwent simultaneous arthroscopic ACLR and LMPRT repair. All patients had chronic injuries, with a mean time since ACL rupture of 7.9 months. Patient characteristics, Lachman and pivot-shift test results, type of LMPRT, associated injuries, and surgery details were documented. Pre- and postoperative functional status was assessed using the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Lysholm score. An independent single-tunnel transtibial repair using 2 SutureTapes was performed for Forkel type 1 and 3 tear root avulsions, while side-to-side suture repair was performed for type 2 radial/oblique tears. The Wilcoxon signed rank test and minimal clinically important difference (MCID) of the IKDC score were used for statistical analysis.

Results:

Included were 25 patients with a mean age of 29.6 ± 6.5 years. Of these, 22 patients (88%; 95% CI, 73.1%-100%) had a high-grade (grade 2 or 3) preoperative pivot shift. Diagnosis of the LMPRT on magnetic resonance imaging (MRI) scans was possible only in 5 patients (20%). At final evaluation, performed at 37.4 ± 7.1 months postoperatively, all functional scores had improved significantly from preoperatively: IKDC score, from 47.6 ± 9.5 to 81.8 ± 11.5; KOOS, from 45.5 ± 10.9 to 86.5 ± 10.3, and Lysholm score, from 49.0 ± 11.5 to 88.8 ± 7.6 (P < .001 for all). Twenty-four patients (96%) achieved the MCID for the IKDC score. All knees had a negative pivot shift at final analysis, and no patient underwent revision ACLR or LMPRT repair.

Conclusion:

LMPRT repair combined with ACLR led to good short-term clinical outcomes in this study. An LMPRT may frequently go undetected on preoperative MRI scans, but a high-grade pivot shift is present in a large majority of these patients.

Medial meniscal extrusion greater than 4 mm reduces medial tibiofemoral compartment contact area: a biomechanical analysis of tibiofemoral contact area and pressures with varying amounts of meniscal extrusion

PURPOSE

The primary objective of this study is to evaluate the contact areas, contact pressures, and peak pressures in the medial compartment of the knee in six sequential testing conditions. The secondary objective is to establish how much the medial meniscus is able to extrude, secondary to soft tissue injury while keeping its roots intact.

METHODS

Ten cadaveric knees were dissected and tested in six conditions: (1) intact meniscus, (2) 2 mm extrusion, (3) 3 mm extrusion, (4) 4 mm extrusion, (5) maximum extrusion, (6) capsular based meniscal repair. Knees were loaded with a 1000-N axial compressive force at 0°, 30°, 60°, and 90° for each condition. Medial compartment contact area, average contact pressure, and peak contact pressure data were recorded.

RESULTS

When compared to the intact state, there was no statistically significant difference in medial compartment contact area at 2 mm of extrusion or 3 mm of extrusion (n.s.). There was a statistically significant decrease in contact area compared to the intact state at 4 mm (p = 0.015) and maximum extrusion (p < 0.001). The repair state was able to improve medial compartment contact area, and there was no statistically significant difference between the repair and the intact states (n.s.). No significant differences were found in the average contact pressure between the repair, intact, or maximum extrusion conditions at any flexion angle (n.s.). No significant differences were found in the peak contact pressure between the repair, intact, or maximum extrusion conditions at any flexion angle (n.s.).

CONCLUSION

In this in vitro model, medial meniscus extrusion greater than 4 mm reduced medial compartment contact area, but meniscal extrusion did not significantly increase pressure in the medial compartment. Additionally, meniscal centralization was effective in restoring the medial tibiofemoral contact area to intact state when the meniscal extrusion was secondary to meniscotibial ligament injury. The diagnosis of meniscal extrusion may not necessarily involve meniscal root injury. Since it is known that meniscal extrusion greater than 3 or 4 mm has a biomechanical impact on tibiofemoral compartment contact area and pressures, specific treatments can be established. Centralization restored medial compartment contact area to the intact state.

Good Surgical Outcomes After Concomitant Repair of Double Radial Tears of the Lateral Meniscus and Anterior Cruciate Ligament Reconstruction

Purpose

To describe double radial tears of the lateral meniscus (LM), report early clinical treatment outcomes, and determine reoperation and failure rates.

Methods

Twenty-one (N = 21) consecutive cases of arthroscopic-treated lateral meniscus double radial tears treated between 2012 and 2018 were reviewed, including 15 males (71.4%) and 6 females (28.6%). Meniscus repairs were all performed at the time of anterior cruciate ligament (ACL) reconstruction. Patients with associated fractures or prior surgeries were excluded. Concomitant injuries were reported, as were preinjury and postoperative Tegner scores, preoperative and postoperative visual analogue pain scale (VAS) scores, and postoperative International Knee Documentation Committee (IKDC) subjective scores. Reoperation and failure rates were documented.

Results

Twenty-one (N = 21) tears were located in the posterior horn of the meniscus near the root attachment; 15 (71.4%) underwent all-inside repair, 4 (19.0%) underwent transtibial pull-through repair, 1 (4.8%) was partially debrided, and 1 (4.8%) was left untreated. Twenty-one tears (N = 21) were in the body of the meniscus; 7 (33.3%) were repaired, 7 (33.3%) were partially debrided, and 7 (33.3%) were left untreated. Thirteen patients (62%) had associated medial collateral ligament (MCL) injuries. Mean follow-up was 2.6 years. VAS at rest and with activity improved by 2.1 points (P < .001) and 3.1 points (P = .017) after surgery. The mean postoperative Tegner activity score was 6.4, and the mean IKDC score was 83.2 at final follow-up. Reoperation was required in 5 patients (23.8%), and the surgical treatment failed in 1 patient (4.7%).

Conclusions

Double radial tears of the LM are uncommon injuries that occur in the setting of ACL tears, usually combined with MCL injury. The variety of surgical treatment techniques have a low failure rate at short-term follow-up. Patients tend to have good clinical outcomes with improvement in pain and overall function after surgically treating these injuries with simultaneous ACL reconstruction.

Level of Evidence

Level IV, therapeutic study, case series

Arthroscopic incidence of lateral meniscal root avulsion in patients with anterior cruciate ligament injury

Background

To arthroscopically evaluate the incidence of lateral meniscal root avulsion (LMRA) and associated intra-articular injuries in patients undergoing anterior cruciate ligament (ACL) reconstruction.

Materials and Methods

From April 2014 to March 2017, 532 consecutive patients were diagnosed as having an ACL injury and underwent arthroscopic ACL reconstruction. The diagnosis of LMRA was made arthroscopically. The effects of gender, activity, grade of laxity, time from injury, and concomitant meniscal lesions were analyzed.

Results

Among 532 patients, 497 (93.4%) underwent primary ACL reconstruction and 35 (6.5%) underwent revision procedures. 383 were acute or subacute injuries (less than 6 months from injury to surgery) and 149 chronic (more than 6 months). Average age was 30.4 years (DS: ± 11.04); there were 422 (79.3%) males and 110 (20.6%) females. A LMRA associated with the ACL injury was detected in 72 cases (13.5%), with a significant prevalence observed in males (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\chi ^2}$$\end{document}χ2 = 4.65; P = 0.031, statistically significant). In the 149 patients with a chronic injury, 27 patients had LMRA (18.1%), while 45 of the 383 patients with an acute or subacute injury had LMRA (11.7%). There was a tendency, albeit not significant (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\chi ^2}$$\end{document}χ2 = 3.721; P = 0.054), for the prevalence to increase with time since the initial ACL injury. LMRA was significantly associated (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\chi ^2}$$\end{document}χ2 = 7.81; P = 0.006) with a meniscocapsular tear of the posterior horn of the medial meniscus (ramp lesion). No other significant associations, such as with severity of A-P translation (as measured by KT-2000) or activity level, were detected.

Conclusion

LMRA is a relatively common injury associated with both acute and chronic ACL tears. A relatively high incidence in cases of chronic ACL insufficiency suggests that LMRAs do not heal spontaneously or that they may appear with time, even when absent at the time of the initial injury.

Level of evidence

Level III, cross-sectional study.

H-Plasty Repair Technique Improved Tibiofemoral Contact Mechanics After Repair for Adjacent Radial Tears of Posterior Lateral Meniscus Root: A Biomechanical Study

PURPOSE

To compare the time-zero tibiofemoral contact mechanics among the 4 different suturing repairs: transtibial pullout suture repair, suture anchor repair, side-to-side repair, and H-plasty repair.

METHODS

Twenty-four human cadaveric knees were included. Each lateral meniscus condition (intact, radial tear, and repair) was tested under a 1000-N axial compressive load at 0°, 30°, 60°, and 90° of flexion. Four different repair techniques, transtibial pullout, suture anchor, side-to-side, and H-plasty repair technique, were tested. Tibiofemoral mean and peak contact pressure and contact area in the lateral and medial compartments were measured by Tekscan sensors.

RESULTS

Radial tears adjacent to the posterior lateral meniscus root produced significantly decreased contact area and increased mean and peak contact pressures in the lateral compartment across all angles (P < .05). All repair groups could improve the contact mechanics relative to the torn condition (P < .05), but only H-plasty repair showed no significant difference in the mean and peak contact pressure and contact area compared with that of the intact state at all flexion angles (P > .05).

CONCLUSIONS

The results showed that the tibiofemoral contact mechanics after adjacent radial tears of the posterior lateral meniscal root were improved to the intact level by H-plasty repair at time-zero. The additional vertical mattress sutures act as "stabilizers" to provide a more stable environment in distributing vertical tibiofemoral pressure. The other 3 repair techniques also significantly improved lateral tibiofemoral contact mechanics relative to the corresponding tear conditions.

CLINICAL RELEVANCE

The results of this study suggest that H-plasty repair can restore the biomechanical properties to the intact state. Since it was a time-zero cadaveric study, the results should be carefully used in clinical practices.

Cavendish P, P. Quinn J, DiBartola AC, Flanigan DC. Repair of Radial Meniscus Tears Results in Improved Patient-Reported Outcome Scores: A Systematic Review

PURPOSE

To quantify healing rates and patient-reported outcome scores following repair of radial meniscus tears.

METHODS

PubMed, Scopus, and Embase databases were searched according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria included: human subjects with meniscal tears, full-text English language, average follow-up of at 1 year, and publication after the 2000. Exclusion criteria included technical, biomechanical, and cadaveric studies. Study quality was assessed using Coleman Methodology Scores and Methodological Index for Non-Randomized Studies (MINORS) criteria.

RESULTS

Twelve studies reported on the repair of 243 radial tears in 241 patients. The mean Modified Coleman Methodology Score was 46.8, range 26-60, with a mean level of evidence of 3.5. Arthroscopic techniques were used in all studies, with 1 study using an arthroscopic-assisted 2-tunnel trans-tibial pullout technique. The mean patient age was 32 years (11-71). The mean follow-up was 35 months (12 to 75.6). The average time to surgery was 10.9 months (0.5-22.4). Eight of the 12 studies reported concomitant anterior cruciate ligament (ACL) reconstruction, with 64% having concomitant ACL injury. The most common outcome measure was the Lysholm score, which improved from 47-68.9 preoperatively to 86.4-95.6 postoperatively. Tegner Activity Scale improved from 2.5-3.1 preoperatively to 4.7-6.7 postoperatively. Healing rates were reported via magnetic resonance imaging and second-look arthroscopy. Second-look arthroscopy was performed for a variety of indications, including removal of screw, washers or plates, dissatisfaction with original procedure, partial healing found on magnetic resonance imaging, or desire of the patient to know the true healing status before return to sport. Of those assessed, 62.0% had complete healing, 30.0% partial healing, and 8.0% failure to heal.

CONCLUSIONS

Patient-reported outcomes of radial meniscus repair with and without ACL reconstruction are encouraging, with high patient-reported outcomes reported at final follow-up when compared with preoperative scores. Among all meniscus repairs assessed for healing, the majority demonstrated at least some healing with an overall low rate of failure.

LEVEL OF EVIDENCE

IV; systematic review of level III-IV studies.

High prevalence of a deep lateral femoral notch sign in patients with anterior cruciate ligament (ACL) and concomitant posterior root tears of the lateral meniscus

PURPOSE

To determine the prevalence of a deep lateral femoral notch sign (LFNS) in magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) and concomitant posterior root tears of the lateral meniscus (PLRT).

METHODS

A retrospective chart review was conducted to identify all patients undergoing ACL reconstruction between 2016 and 2018. Based on the arthroscopic appearance of the lateral meniscus, patients were assorted to one of three groups: isolated ACL tear (ACL-Group), ACL tear with concomitant lateral meniscus tear not involving the posterolateral root (Meniscus-Group), and ACL tear with concomitant PLRT (PLRT-Group). Incidence and depth of a LFNS on preoperative MRI was compared between the three cohorts.

RESULTS

115 patients (mean age: 29.5 ± 11.3 years) were included in the study, with 58 patients (50.4%) assorted to the ACL-Group, 24 patients (20.9%) to the Meniscus-Group, and 33 patients (28.7%) to the PLRT-Group. The prevalence of a LFNS was significantly higher in the PLRT-Group (39.4%), when compared to the ACL- (5.2%) or Meniscus-Groups (25.0%; p < 0.001, respectively). Additionally, logistic regression analysis demonstrated that patients with PLRT were 5.3 times more likely to have a LFNS as compared to those without a lateral root tear (p < 0.001).

CONCLUSION

In patients with ACL tears, the presence of a LFNS on preoperative MRI may be predictive for a PLRT. As the LFNS occurs in almost 40% of the patients with combined ACL tears and PLRT, the LFNS may be a useful secondary diagnostic finding in early MRI diagnostic. Identifying PLRT on MRI is clinically relevant, as it prevents misdiagnosis and facilitates surgical decision-making, thus avoiding subsequent delayed treatment.

LEVEL OF EVIDENCE

Level IV.

Clinical, Radiographic, and Arthroscopic Outcomes of Surgical Repair for Radial and Avulsed Lesions on the Lateral Meniscus Posterior Root During ACL Reconstruction: A Systematic Review

Background

Clinical outcomes of surgical repairs for tears of the lateral meniscus posterior root (LMPR) in patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) have not been comprehensively investigated.

Purpose

To systematically review the clinical, radiographic, and arthroscopic results of surgical repairs for tears of the LMPR in patients undergoing ACLR.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic electronic search of the PubMed and Embase databases was performed to identify studies reporting clinical, radiographic, or arthroscopic results of surgical repairs for tears of the LMPR in patients undergoing ACLR. Each included study was abstracted regarding study characteristics, patient characteristics, surgical technique, and outcome measures. The methodological quality of the included studies was analyzed according to the Methodological Index for Non-Randomized Studies (MINORS) criteria.

Results

Nine studies were included in this systematic review, representing a total of 215 knees in 215 patients. Overall, 123 side-to-side repairs and 89 pullout repairs were performed for tears of the LMPR during ACLR. After a mean follow-up of 33.9 months, significant improvements (P < .05) were found in the mean Lysholm score (from 58.3 to 91.4) as well as the mean International Knee Documentation Committee subjective score (from 61.1 to 87.2). Weightbearing anteroposterior radiographs of 41 patients showed no significant narrowing of lateral joint space width. On magnetic resonance imaging scans, 31 patients demonstrated no significant progression of chondral lesions, and no significant decreases in meniscal extrusion on coronal planes were reported in another 76 patients. The complete/partial healing was 93.6% on second-look arthroscopy after side-to-side repairs for radial tears of the LMPR. The MINORS value showed a high risk of bias for all 9 studies.

Conclusion

Patients with tears of the LMPR associated with ACL injuries achieved favorable functional scores after ACLR and LMPR repairs, and the side-to-side repair for radial tears of the LMPR succeeded in a high meniscal healing rate of >90%. However, the authors of this review were unable to definitively conclude whether LMPR repairs fully restore the hoop stress of the lateral meniscus.

Role of the Meniscofemoral Ligaments in the Stability of the Posterior Lateral Meniscus Root After Injury in the ACL-Deficient Knee

» Injuries to the posterior root of the lateral meniscus occur frequently in acute knee injuries with concomitant tearing of the anterior cruciate ligament (ACL). » The meniscofemoral ligaments (MFLs), consisting of the anterior MFL (ligament of Humphrey) and the posterior MFL (ligament of Wrisberg), as well as the osseous attachment of the meniscal root, stabilize the lateral meniscus, enabling appropriate load transmission and maintenance of contact forces within the lateral compartment of the knee during loading and range of motion. » In the setting of an ACL injury to the knee with osseous root injury of the posterior root of the lateral meniscus, the MFLs (when present) may stabilize the lateral meniscus against meniscal extrusion, thereby maintaining appropriate contact mechanics within the knee, decreasing the risk of subsequent chondral and meniscal injury and the development of premature osteoarthritis. » Additional study on the indications for posterior meniscal root repair during ACL reconstruction is warranted since the ideal management of lateral root injury in the MFL-intact knee remains unknown.

Tibiofemoral Contact Mechanics After Horizontal or Ripstop Suture in Inside-Out and Transtibial Repair for Meniscus Radial Tears in a Porcine Model

PURPOSE

To compare tibiofemoral contact mechanics after horizontal or ripstop (horizontal plus vertical) sutures in inside-out and transtibial repair for meniscal radial tears with 10 porcine knees in each group.

METHODS

Ten matched pairs of porcine knees were tested under a 1500-N axial compressive load at 0°, 30°, 60°, and 90° of knee flexion. Each knee underwent 4 testing conditions consecutively: (1) intact, (2) medial meniscal radial tear, (3) horizontal suture repair configuration, and (4) ripstop suture repair configuration. Tekscan sensors measured tibiofemoral contact pressure and contact area in the medial and lateral compartments.

RESULTS

All repair groups improved their contact mechanics when compared with the tear state among all flexion angles analyzed (all P < .05). Furthermore, ripstop sutures with both inside-out and transtibial repairs restored intact knee contact area and pressures (peak and mean) in the medial compartment at all flexion angles, whereas the horizontal sutures alone failed to do so for contact pressures at 60° and 90° and for contact surface areas at all flexion angles. However, the aforementioned parameters were not significantly different between inside-out sutures and transtibial sutures, regardless of horizontal or ripstop configuration (P > .05).

CONCLUSIONS

Radial tears of the meniscus in a porcine model significantly decreased medial contact area and increased mean and peak contact pressure. Both inside-out and transtibial ripstop repairs for radial tears aid in restoring intact tibiofemoral contact mechanics at all assessed knee flexion angles.

CLINICAL RELEVANCE

Our results suggest that both inside-out and transtibial ripstop repairs for radial tears can restore tibiofemoral contact mechanics to the intact state. Since the study were performed in an open fashion porcine model, the results should be carefully used in clinical practices, and the efficacy of the techniques through arthroscopic method should be further explored.

Repair of the Posterior Lateral Meniscal Root Tear: Suture Anchor Fixation Through the Outside-In Anterior Cruciate Ligament Reconstruction Femoral Tunnel

Posterior lateral meniscus root tears are defined as tears that occur within 9 mm of the posterior lateral meniscus insertion or as avulsions of the insertion. If root tears are left unrepaired, functional alterations and early degenerative changes occur in the affected compartment. Several surgical techniques have been described to reattach the posterior horn of the lateral meniscus, including transtibial pull-out technique and side-to-side repair technique. This surgical technique reports an alternative way to repair posterior lateral meniscus root tears that are associated with or without an anterior cruciate ligament graft tear. The technique involves the placement of a suture anchor on the lateral meniscus root footprint through the outside-in anterior cruciate ligament femoral tunnel, which minimizes the possibility of iatrogenic lesions and facilitates repair.

Three-dimensional computed tomography confirmed that the meniscal root attachments and meniscofemoral ligaments are morphologically consistent

PURPOSE

To clarify the characteristic features of the meniscal root attachments, meniscofemoral ligaments (MFLs), and related osseous landmarks on three-dimensional images using computed tomography.

METHODS

Twenty-eight non-paired, formalin-fixed human cadaveric knees were evaluated in this study. The meniscal root attachments were identified and marked. Three-dimensional images were obtained after applying a contrast agent to the entire meniscal surfaces and MFLs, then the morphology of the meniscal root attachments and MFLs, and their positional relationships with osseous landmarks, were analyzed.

RESULTS

Parsons' knob divided the medial meniscal anterior root attachment and lateral meniscal anterior root attachment on the anterior portion of the tibial plateau. The medial meniscal posterior root attachment was near the medial intercondylar tubercle. The lateral meniscal posterior root attachment (LMPRA) was closer to the lateral intercondylar tubercle. Both root attachments were near the posterior intercondylar fossa. The positional relationships between the meniscal root attachments and related osseous landmarks were consistent in all specimens. The MFLs originated from the lateral meniscus posterior horn, and the anterior MFL was closer to the LMPRA than the posterior MFL. The posterior MFL originated at approximately the midpoint between the LMPRA and the most posterior margin of the lateral meniscus.

CONCLUSION

This study showed that the relationships between the characteristic features of the meniscal root attachments, MFLs, and related osseous landmarks were consistent. The clinical relevance of this study is that it improved understanding of the anatomy of the meniscal root attachments and MFLs.

All-inside Techniques for Meniscal Radial Root Tear Repair

Meniscal radial root tears can disrupt the load-bearing function of the meniscus and worsen instability in anterior cruciate ligament-deficient knees. Paracentral radial tears adjacent to the root (types 1, 2, and 4) repaired with a transtibial pullout suture technique can lead to over-medialization of the meniscal root and a high-tension nonanatomic repair. We propose 2 all-inside techniques for anatomic repair of medial and lateral meniscal radial root tears with (1) an all-inside meniscal repair device and (2) an antegrade suture passer. We present the technical requirements and tips for these techniques. For lateral meniscal radial root repair with an all-inside meniscal repair device, ideal viewing is from an anterolateral portal with device entry from an anteromedial portal to reduce the risk of vascular injury. We recommend at least 2 stitches across the tear, with the depth setting limited to 18 to 20 mm for a central stitch and 16 mm or less for a peripherally placed stitch. For root repair with an antegrade suture passer, viewing should be from an anteromedial portal with the passer entering from an anterolateral portal. At least 2 stitches should be placed across the tear, with 1 central and 1 peripheral or 1 superior and 1 inferior.

Lateral meniscus posterior root tear in anterior cruciate ligament injury can be detected using MRI-specific signs in combination but not individually

PURPOSE

The purpose of this study was to evaluate (1) the diagnostic value of using single and multiple magnetic resonance imaging (MRI) findings for lateral meniscus posterior root tear (LMPRT) detection in anterior cruciate ligament (ACL) injury and (2) the influence of time from ACL injury to MRI assessment on LMPRT detection. Finally, we investigated the relationship between LMPRT and bone bruising.

METHODS

In all, 231 knees with ACL injury, 32 with LMPRT, were retrospectively assessed. Cases were evaluated for LMPRT based on the cleft, ghost, and truncated triangle signs, used individually or in combination. To assess the influence of the timing of the MRI assessment on LMPRT detection, we also evaluated the overall sensitivity, specificity, and accuracy in cases in which MRI was performed within 2 weeks of injury. The number of condyles with bone bruising was assessed and then compared between patients with and without LMPRT.

RESULTS

Although the sensitivity and specificity of the three signs individually were 34.4-65.6% and 94.0-97.0%, when at least one of these signs was positive, the sensitivity and specificity were 84.4% and 90.5%, respectively. However, the diagnostic value of each sign when MRI was performed within 2 weeks of injury was lower than the overall value. There was a significant difference in the number of condyles with bone bruising between the LMPRT (3 ± 1) and non-LMPRT (2 ± 2) groups.

CONCLUSIONS

Although the sensitivity of each sign for LMPRT was low, LMPRT could be detected adequately if these signs were used in combination. Therefore, surgeons should detect LMPRT using these three signs in combination, not individually.

LEVEL OF EVIDENCE

IV.

A novel surgical technique for arthroscopic repair of type II posterior lateral meniscal root tear

BACKGROUND

Several suture repair techniques have been reported for radial tear close to the posterior lateral meniscal root (type II PLMRT). However, no study has evaluated the clinical results after repair using the FasT-Fix system. This paper describes a novel H-plasty surgical repair technique and reports its clinical results.

METHODS

From January 2015 to January 2017, 47 patients underwent repair of type II PLMRT with concomitant anterior cruciate ligament reconstruction and were included in this study. Assessments performed preoperatively and at final follow-up included the Lysholm score, subjective International Knee Documentation Committee (IKDC) score, and knee stability assessments (pivot-shift test, Lachman test, KNEELAX arthrometer side-to-side difference). Magnetic resonance imaging was used to compare the lateral meniscal extrusion pre- versus postoperatively. Second-look arthroscopy was performed to evaluate the meniscal healing in 38 cases.

RESULTS

Forty-seven patients were followed up for an average of 30.7 months (range 18-46 months). No patients experienced meniscal mechanical symptoms. At final follow-up, there were significant improvements in the Lysholm score, IKDC score, knee stability assessments, and lateral meniscal extrusion compared with the preoperative values. In the 38 of 47 patients that underwent second-look arthroscopy after an average of 17.5 months (range 14-19 months), all repairs (100%) were completely healed.

CONCLUSIONS

The novel H-plasty repair using the FasT-Fix system was an effective surgical treatment for type II PLMRT. Considering the satisfactory clinical results and the convenience of the surgery, H-plasty repair is recommended to be used preferentially.

Hyperflexion Knee Injury with Anterior Cruciate Ligament Rupture and Avulsion Fractures of Both Posterior Meniscal Attachments: A Case Report

CASE

A 54-year-old patient presented with low-velocity hyperflexion knee trauma while falling at a ski lift with anterior cruciate ligament (ACL) rupture and avulsion fractures of both posterior meniscal attachments. Meniscal avulsions were treated arthroscopically using transtibial sutures; a partial medial collateral ligament tear was treated conservatively. Six weeks later, reconstruction of the ACL was performed, and both meniscal attachments were stable.

CONCLUSION

Hyperflexion of the knee puts direct shear and compressive force on the posterior tibia. This can result in ligament injuries combined with avulsion fractures of both posterior meniscal attachments. Arthroscopic treatment is a practicable technique for this type of injury.

Rebar Repair of Radial Meniscus Tears: A Reinforced Suture Technique

The purpose of this paper is to describe the rebar repair as a technique for repair of radial meniscus tears and compare the rebar technique with current techniques used for meniscus repairs. This technique consists of 4 sutures placed with the inside-out technique. First, the vertical mattress reinforcement sutures are placed anteriorly and posteriorly to the tear. Then, 2 parallel horizontal sutures are placed directly in juxtaposition to the vertical sutures, ensuring the needles pass on the side of the reinforcing stitch away from the tear. This technique is less technically challenging than other meniscus repair techniques that require drilling of a transtibial tunnel. Overall, the rebar technique offers a more optimal way for stabilizing the meniscus by using 2 reinforcement sutures that run with the circumferential fibers to help restore the natural hoop stress of the meniscus. Also, the placement of the vertical mattress sutures in the rebar technique offers more direct reinforcement to the horizontal mattress sutures as compared with other techniques, which reduces the risk of pull-out tears.

Quantitative Evaluation of Dynamic Lateral Meniscal Extrusion After Radial Tear Repair

Background:

Radial tears of the lateral meniscus frequently accompany acute anterior cruciate ligament (ACL) injuries and lead to increased joint stress and pathological meniscal extrusion (ME). The dynamic behavior of the lateral meniscus after radial tear repair with respect to ME has not been described.

Purpose:

To quantitatively assess dynamic lateral ME after all-inside radial tear repair.

Study Design:

Case series; Level of evidence, 4.

Methods:

Patients who underwent ACL reconstruction and all-inside radial tear repair of the lateral meniscus and had no history of contralateral knee injuries were included. Magnetic resonance imaging scans were acquired in loaded (50% of body weight) and unloaded conditions of both the injured and noninjured knees. A custom-made pneumatically driven knee brace was used for standardized knee positioning in 10° of flexion and with axial load application. Quantitative measures included the absolute lateral ME, meniscal body extrusion ratio, and Δ extrusion. Preoperative and postoperative unloaded extrusion data were compared by paired t tests. For postoperative data, the concomitant influence of the factors “leg” and “condition” were assessed through factorial analyses of variance.

Results:

A total of 10 patients with a mean follow-up of 47.9 months were enrolled. The intraclass correlation coefficient (ICC) confirmed good interrater reliability (ICC, 0.898) and excellent intrarater reliability (ICC, 0.976). In the unloaded injured leg, all-inside repair reduced ME from 3.15 ± 1.07 mm to 2.13 ± 0.61 mm (–32.4%; P = .033). Overall, load application led to a significant increase in ME (+0.34 mm [+21.8%]; P = .029). Significantly greater ME was observed in the injured knee (+1.10 mm [+93.2%]; P = .001) than in the noninjured knee. The condition × leg interaction was not significant (P = .795), suggesting that the compression-associated increase in ME did not differ significantly between the injured and noninjured knees.

Conclusion:

Lateral ME depends on the knee status and loading condition. All-inside repair of radial meniscal tears led to a reduction of extrusion with no alteration in dynamic lateral ME. Meniscus-preserving therapy is recommended in the case of a radial lateral meniscal tear to preserve its dynamic behavior.

Arthroscopic side-to-side repair for complete radial posterior lateral meniscus root tears

BACKGROUND

The aim of this study was to determine the radiographic, second-look, and functional outcomes after arthroscopic side-to-side repair for complete radial posterior lateral meniscus root tears (PLMRTs).

METHODS

Patients who underwent arthroscopic side-to-side repair for complete radial PLMRTs were identified. Clinical assessment consisted of symptoms (locking, catching, giving way and effusion), examinations of joint-line tenderness and McMurray test, and subjective scores of International Knee Documentation Committee (IKDC), Lysholm, and Tegner. In addition, postoperative MRI scan and second-look arthroscopy were performed to assess the healing status of the repaired meniscus.

RESULTS

Twenty-nine patients met the inclusion criteria. The mean age was 25.41 years. The mean follow-up period was 26.68 months. During the follow-up, none of the patients had symptoms of meniscal retear, lateral joint-line tenderness or a positive McMurray test. The postoperative subjective scores of IKDC, Lysholm, and Tegner improved significantly compared to the preoperative values (P = 0.01). Postoperative MRI scan showed that 28/29 (96.6%) patients achieved meniscus healing. Twenty-two patients underwent second-look arthroscopy, among whom 19 (86.4%) patients showed complete meniscus healing and 3 (13.6%) patients showed partial healing.

CONCLUSION

Arthroscopic side-to-side repair was a valuable surgical repair technique for complete radial PLMRTs, which leaded to significant improvements in both objective and subjective functional outcomes with a high rate of meniscus healing.

LEVEL OF EVIDENCE

Level IV, case series.

Lateral Meniscus Repair Using Posterolateral Portal: Suture Hook Technique

Lateral meniscus lesions result in loss of meniscus hoop stresses and can lead to lateral compartment overload and early degenerative changes. Arthroscopic suture repair provides good long-term results. However, posterior vertical tears in the peripheral area of the meniscus can be technically challenging to resolve. This Technical Note describes the suture hook technique using an accessory posterolateral portal. We believe it is a safe, effective method for repairing full vertical tears of the lateral meniscus.

Arthroscopic Repair of Double Radial Tears of the Lateral Meniscus

Double radial tears of the lateral meniscus are rare injuries that typically occur in the setting of an acute anterior cruciate ligament rupture. Full-thickness radial tears of the meniscus body and root render the meniscus nonfunctional from a loss of hoop stress resistance. Repair of these tears can normalize contact pressures in the lateral compartment and delay arthritic changes. We describe our technique for repairing a lateral meniscus body radial tear and concomitant posterior root tear, via inside-out suture repair and transtibial suture repair, respectively. This investigation was performed at Mayo Clinic.

Risk Factors for Lateral Meniscus Posterior Root Tears in the Anterior Cruciate Ligament-Injured Knee: An Epidemiological Analysis of 3956 Patients From the SANTI Study Group

BACKGROUND

Lateral meniscus posterior root tears (LMPRTs) result in loss of hoop forces and significant increases in tibiofemoral contact pressures. Preoperative imaging lacks reliability; therefore, holding an appropriate index of suspicion, based on the epidemiology of and risk factors for LMPRT, may reduce the rate of missed diagnoses.

PURPOSE

The primary objectives of this study were to evaluate the incidence of and risk factors for lateral meniscus root lesions in a large series of patients undergoing anterior cruciate ligament (ACL) reconstruction.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

All patients who underwent primary or revision ACL reconstruction by a single surgeon between January 2011 and April 2018 were considered for study eligibility. From this overall population, all patients who underwent repair of an LMPRT were identified. The epidemiology of LMPRT was defined by the incidence within the study population, stratified by key demographic parameters. Potentially important risk factors for the presence of LMPRT were evaluated in multivariate logistic regression analysis.

RESULTS

A total of 3956 patients undergoing ACL reconstruction were included in the study. An LMPRT was identified and repaired in 262 patients (6.6%). Multivariate analyses demonstrated that significant risk factors for LMPRT included a contact sports injury mechanism (7.8% incidence with contact sport mechanism vs 4.5% with noncontact mechanism; odds ratio, 1.69; 95% CI, 1.266-2.285; P < .001) and the presence of a medial meniscal tear (7.9% incidence with medial meniscal tear vs 5.8% without; odds ratio, 1.532; 95% CI, 1.185-1.979; P < .001). Although the incidence of LMPRT in male patients (7.3%) was higher than in females (4.8%), this was not significant in multivariate analysis ( P = .270). Patient age, revision ACL reconstruction, and a preoperative side-to-side laxity difference ≥6 mm were not significant risk factors for LMPRT.

CONCLUSION

The incidence of LMPRT was 6.6% in a large series of patients undergoing ACL reconstruction. Participation in contact sports and the presence of a concomitant medial meniscal tear were demonstrated to be important independent risk factors. Their presence should raise the index of suspicion for this injury pattern.

Lateral Meniscal Posterior Root Repair With Anterior Cruciate Ligament Reconstruction Better Restores Knee Stability

BACKGROUND

The effect of lateral meniscal posterior root tear and repair-commonly seen in clinical practice in the setting of anterior cruciate ligament (ACL) reconstruction-is not known.

PURPOSE/HYPOTHESIS

This study evaluated the effect of tear and repair of the lateral meniscal posterior root on the biomechanics of the ACL-reconstructed knee. It was hypothesized that anterior tibial translation would increase under anterior loading and simulated pivot-shift loading with the root tear of the posterior lateral meniscus, while repair of the root tear would reduce it close to the noninjured state.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirteen fresh-frozen adult human knees were tested with a robotic testing system under 2 loading conditions: (1) an 89.0-N anterior tibial load applied at full extension and 15°, 30°, 60°, and 90° of knee flexion and (2) a combined 7.0-N·m valgus and 5.0-N·m internal tibial torque (simulated pivot-shift test) applied at full extension and 15° and 30° of knee flexion. The following knee states were tested: intact knee, ACL reconstruction and intact lateral meniscus, ACL reconstruction and lateral meniscal posterior root tear, and ACL reconstruction and lateral meniscal posterior root repair.

RESULTS

In the ACL-reconstructed knee, a tear of the lateral meniscal posterior root significantly increased knee laxity under anterior loading by as much as 1 mm. The transosseous pullout suture root repair improved knee stability under anterior tibial and simulated pivot-shift loading. Root repair improved the ACL graft force closer to that of the native ACL under anterior tibial loading.

CONCLUSION

Lateral meniscal posterior root injury further destabilizes the ACL-reconstructed knee, and root repair improves knee stability.

CLINICAL RELEVANCE

This study suggests a rationale for surgical repair of the lateral meniscus, which can restore stability close to that of the premeniscal injury state.

Comparative Outcomes of Radial and Bucket-Handle Meniscal Tear Repair: A Propensity-Matched Analysis

BACKGROUND

Full-thickness radial meniscal tears render the meniscus nonfunctional and have historically been treated with partial meniscectomy. As preservative techniques evolve for radial repair, comparisons with other tear patterns are necessary to evaluate repair efficacy and prognosis.

PURPOSE

To assess clinical outcomes and reoperation rates of radial meniscal repair and to compare them to bucket-handle meniscal repair.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Radial and bucket-handle meniscal tears without concurrent root injuries undergoing surgical repair at a single institution between 2007 and 2015 were analyzed, including both all-inside and inside-out suturing techniques. Propensity matching was performed on the basis of age at surgery, sex, meniscus laterality, body mass index (BMI), and concomitant anterior cruciate ligament reconstruction (ACLR) using a comparison pool of 70 bucket-handle repairs. Reoperation-free survival rates and Tegner, visual analog scale (VAS) for pain, and International Knee Documentation Committee (IKDC) scores were analyzed.

RESULTS

Twenty-four patients (18 male, 6 female; mean age, 22.8 ± 11.9 years) who underwent repair of a radial meniscal tear were followed for a mean of 3.5 years (range, 2.0-6.3 years). Significant postoperative improvements in VAS scores at rest and with use and IKDC scores were noted postoperatively ( P < .001). Five patients (20.8%) required a reoperation. Subsequently, 18 patients with radial tears (mean age, 19.1 ± 9.1 years; 12 male; mean BMI, 27.0 ± 6.2 kg/m²; 3 medial; 11 ACLR) were propensity matched to 18 patients with bucket-handle tears (mean age, 20.8 ± 5.1 years; 13 male; mean BMI, 25.0 ± 3.5 kg/m²; 3 medial; 11 ACLR). The matched radial and bucket-handle groups demonstrated similar ( P = .17) reoperation-free survival rates at 2 years (88.9% and 94.4%, respectively) and 5 years (77.8% and 87.7%, respectively). VAS and IKDC scores improved significantly after surgery ( P < .001), with no difference noted between the groups ( P ≥ .17). Patients with radial and bucket-handle meniscal repairs achieved mean postoperative Tegner scores (6.6 and 6.6, respectively) not significantly different from their preinjury levels (6.9 and 6.7, respectively) ( P ≥ .32).

CONCLUSION

Satisfactory clinical outcomes are achievable for radial meniscal tear repair at short-term follow-up. In a robustly matched comparison, radial and bucket-handle meniscal tears demonstrate similar improvements in VAS and IKDC scores, restoration of preoperative Tegner scores, and acceptable reoperation rates. Full-thickness radial meniscal tears should be considered for repair.

High Rate of Missed Lateral Meniscus Posterior Root Tears on Preoperative Magnetic Resonance Imaging

Background:

Lateral meniscus posterior root tears (LMPRTs), if left untreated, can cause devastating effects to the knee, with rapid articular cartilage degeneration and loss of the meniscus as a secondary stabilizer. Detection and surgical repair of these defects have been linked to favorable outcomes, but preoperative identification of LMPRTs continues to be challenging.

Purpose:

To determine the rate of LMPRTs diagnosed preoperatively on magnetic resonance imaging (MRI) in a consecutive series of arthroscopically confirmed LMPRTs.

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective cohort of 45 consecutive patients with arthroscopically confirmed LMPRTs between 2010 and 2017 were included in this study. The preoperative MRI report for each patient was evaluated and compared with intraoperative findings. Each preoperative MRI study was then reviewed by 2 fellowship-trained musculoskeletal radiologists who worked in consensus.

Results:

A total of 45 patients (32 males, 13 females) with arthroscopically confirmed LMPRTs and a mean age of 27 years (range, 14-54 years) were included in the study. Only 15 of 45 LMPRTs (33%) were initially diagnosed on preoperative MRI. Past or concurrent anterior cruciate ligament (ACL) reconstruction was present in 37 of 45 cases (82%). Upon retrospective review, 15 of the 30 missed LMPRTs were “clearly evident,” 12 “subtly evident,” and 3 “occult” (unavoidably missed). There were no significant differences in the rate of LMPRT diagnosis based on history of prior knee surgery, meniscus extrusion, or tearing of the meniscofemoral ligament.

Conclusion:

Despite improved identification of other meniscus tear patterns on MRI, a high percentage of LMPRTs were still missed. In the setting of previous ACL reconstruction, if the root cannot be confidently identified, the MRI interpretation should indicate that “the root is poorly visualized” to alert the surgeon to thoroughly evaluate this structure. The surgeon should maintain a high index of suspicion and carefully probe the posterior root of the lateral meniscus at the time of arthroscopy, especially in cases of ACL injury.

Lateral meniscus posterior root tear contributes to anterolateral rotational instability and meniscus extrusion in anterior cruciate ligament-injured patients

PURPOSE

The purposes of this study were to investigate (1) meniscus status and clinical findings in anterior cruciate ligament (ACL)-injured patients to clarify associations between the meniscus posterior root tear (PRT) and knee instability, and (2) magnetic resonance imaging (MRI) findings of the PRT to clarify sensitivity and specificity of MRI and prevalence of meniscus extrusion.

METHODS

Three hundred and seventeen patients with primary ACL reconstruction were included. PRTs for both medial and lateral sides were confirmed by reviewing surgical records. Preoperative MRI was reviewed to evaluate sensitivity and specificity of the PRT and meniscus extrusion width (MEW). Clinical information regarding the number of giving-way episodes, preoperative KT-1000 measurements and preoperative pivot shift was also assessed.

RESULTS

Thirty-nine patients had a lateral meniscus (LM) PRT, whereas only four patients had a medial meniscus PRT. One hundred and seventeen patients had no meniscus tear (control). Twenty-eight patients (71.8%) showed positive signs of the LMPRT based on at least one view of MR images, with the coronal view showing the highest sensitivity. MEW in the LMPRT group was significantly larger than that in the control group. The preoperative pivot shift test grade in the LMPRT group was significantly greater than that in the control group. There were no significant differences in other parameters.

CONCLUSIONS

In ACL-injured patients, the LMPRT was associated with ALRI as well as with meniscus extrusion. The coronal view of MRI was useful in identifying the LMPRT, although its sensitivity was not high. Therefore, surgeons should prepare to repair PRTs at the time of ACL reconstruction regardless of MRI findings, and they should make every effort to repair the LMPRT.

LEVEL OF EVIDENCE

III.

Second look arthroscopic evaluation of repaired radial/oblique tears of the midbody of the lateral meniscus in stable knees

BACKGROUND

Radial/oblique tears of the midbody of the lateral meniscus significantly impair the ability of the meniscus to withstand the tibiofemoral load, requiring meniscal repair. However, healing status after meniscal repair has not been fully elucidated. This study aimed to evaluate arthroscopic findings after inside-out suture repair for isolated radial/oblique tears of the midbody of the lateral meniscus.

METHODS

From 2011 to 2015, 18 consecutive patients with isolated radial/oblique tears of the midbody of the lateral meniscus underwent arthroscopic inside-out repair with the tie-grip suture technique. All knees were stable with no previous surgery. All patients were evaluated by second-look arthroscopy at six months postoperatively. Activities including jogging were not allowed until meniscal status was evaluated arthroscopically. To analyze factors associated with healing rates, age, time from injury to initial surgery, and tear zone were compared.

RESULTS

Second-look arthroscopy revealed complete healing in four (22%) patients, partial healing in seven (39%), and failure to heal in seven (39%). Significant differences were observed for tear zone (p < 0.0001), but not for age and timing of repair.

CONCLUSIONS

Arthroscopic evaluation revealed that inside-out repair with the tie-grip suture technique for isolated radial/oblique tears of the midbody of the lateral meniscus achieved complete or partial healing only in 61% of patients. Satisfactory results were observed particularly in patients with tears extending to the vascular zone, whereas those with tears in the avascular zone failed to achieve healing. Therefore, the operative indication of inside-out repair for radial/oblique tears of the midbody of the lateral meniscus might be limited to tears extending into the vascular zone. Given that 39% of cases were arthroscopically considered a failure even if patients complained of no symptoms in daily life, decisions should be made carefully to allow patients to return to sports activities.

Posterior Lateral Meniscus Root Reattachment With Suture Anchors: An Arthroscopic Technique

The posterior lateral meniscus root (PLMR) provides the circumferential tension required to stabilize the lateral meniscus. Thus, preservation of the PLMR is important to prevent an increase in tibiofemoral contact pressure, which could result in osteoarthritis. We describe an all-arthroscopic approach to the fixation of PLMR using suture anchors through associated posterolateral arthroscopic portals that result in a more favorable inclination of the anchors. Initially, the anatomical insertion site of the root on the tibial plateau is debrided, 1 to 2 anchors are placed through the posterolateral portals into the root's footprint area, and the meniscus is finally sutured from the posterolateral portals. Compression of the meniscus is achieved with bone contact. This technique achieves lateral meniscus root fixation, reducing the risk of subluxation of the meniscus and subsequent osteoarthritis.

Suture Repair of Full Radial Posterior Lateral Meniscus Tears Using a Central Midline Portal

Full radial posterior lateral meniscus root tears are frequently associated with injuries to the anterior cruciate ligament. Left unrepaired, they result in loss of the meniscus hoop stress function and can lead to overload of the lateral compartment and early degenerative changes. Arthroscopic suture repairs show successful results with long-term follow-up. However, previously described suture repair techniques have often required special instrumentation and can be technically demanding. This Technical Note describes the use of an accessory portal through the patellar tendon as a safe and easy method for repairing full posterior radial tears of the lateral meniscus.

Two-Tunnel Transtibial Repair of Radial Meniscus Tears Produces Comparable Results to Inside-Out Repair of Vertical Meniscus Tears

BACKGROUND

Radial meniscus tears disrupt the circumferential fibers and thereby compromise meniscus integrity. Historically, radial tears were often treated with meniscectomy because of an incomplete understanding of the biomechanical consequences of these tears, limited information regarding the biomechanical performance of repair, and the technical difficulty associated with repair. There is a paucity of studies on the outcomes of the repair of radial meniscus tears. Purpose/Hypothesis: The purpose was to determine the outcomes of 2-tunnel transtibial repair of radial meniscus tears and compare these results to the outcomes of patients who underwent the repair of vertical meniscus tears with a minimum of 2-year follow-up. The hypothesis was that radial and vertical meniscus tear repair outcomes were comparable.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent 2-tunnel transtibial pullout repair for a radial meniscus tear were included in this study and compared with patients who underwent inside-out repair for a vertical meniscus tear. Subjective questionnaires were administered preoperatively and at a minimum of 2-year follow-up, including the Lysholm score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Short Form-12 (SF-12) physical component summary (PCS), the Tegner activity scale, and patient satisfaction. Analysis of covariance was used to compare postoperative outcome scores between the meniscus repair groups while accounting for baseline scores. Adjusted mean effects relative to the radial repair group were reported with 95% CIs.

RESULTS

Twenty-seven patients who underwent 2-tunnel transtibial pullout repair for radial meniscus tears and 33 patients who underwent inside-out repair for vertical meniscus tears were available for follow-up at a mean of 3.5 years (range, 2.0-5.4 years). No preoperative outcome score significantly differed between the groups. There were no significant group differences for any of the 2-year postoperative outcome scores. Relative to the vertical repair group, the radial repair group exhibited an adjusted mean of -0.2 (95% CI, -5.4 to 4.9), -0.6 (95% CI, -6.6 to 5.5), and 5.1 (95% CI, -3.9 to 14.0) points on the SF-12 PCS, WOMAC, and Lysholm scores, respectively.

CONCLUSION

The 2-tunnel transtibial pullout technique for the repair of radial meniscus tears produces similar clinical outcomes when compared with the repair of vertical meniscus tears at a mean 3.5 years' follow-up.