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

Incidence of Osteoarthritis Diagnosis Within 5 Years of Surgery Was Greater Following Partial Meniscectomy Than Meniscus Repair and/or Anterior Cruciate Ligament Reconstruction

Purpose

To compare knee osteoarthritis (OA) incidence within 5 years of surgery between 5 common sports medicine procedures: isolated anterior cruciate ligament (ACL) reconstruction, isolated meniscus repair (MR), isolated arthroscopic partial meniscectomy (APM), ACL reconstruction with MR (ACL + MR), and ACL reconstruction with APM (ACL + APM).

Methods

The PearlDiver Mariner M157Ortho database was searched. Five cohorts were identified using Current Procedural Terminology (CPT) codes and included those 16 to 60 years old who underwent isolated ACL reconstruction, isolated MR, ACL + MR, isolated APM, or ACL + APM repair. Groups were matched by age, sex, and presence of diagnosis codes for obesity. The incidence of knee OA diagnosis within 5 years of the index procedure was determined for each group, and odds ratios (ORs) were calculated and compared against isolated ACL reconstruction.

Results

Each group consisted of 7,672 patients (3,450 females, 4,222 males). A significantly greater proportion of the APM group was diagnosed with knee OA within 5 years of surgery compared to isolated ACL reconstruction (APM = 1,032/7,672 [13.5%] vs ACL = 745/7,672 [9.7%]; P ≤ .001; OR, 1.45; 95% confidence interval [CI], 1.31-1.60). Similarly, a greater proportion of the MR group was diagnosed with OA compared to isolated ACL reconstruction (MR = 826/7,672 [10.7%]; P = .030; OR, 1.12; 95% CI, 1.01-1.25). No differences in OA incidence were noted between the ACL + APM group when compared to isolated ACL reconstruction (P = .81). Patients undergoing ACL + MR demonstrated the lowest OA incidence with reduced odds when compared to isolated ACL reconstruction (ACL + MR = 575/7,672 [7.5%]; P < .001; OR, 0.75; 95% CI, 0.67-0.84).

Conclusions

In this analysis using CPT codes, APM was associated with the highest knee OA incidence, and ACL + MR was associated with the lowest OA incidence within 5 years of surgery.

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.

Lateral meniscus posterior root repair in the setting of anterior cruciate ligament reconstruction restores joint mechanics to the intact state and improves clinical function: a systematic review of biomechanical and clinical outcomes

PURPOSE

To perform a systematic review of biomechanical and clinical outcomes following lateral meniscus posterior root (LMPR) repair with concomitant anterior cruciate ligament reconstruction (ACLR).

METHODS

A literature search was performed systematically using PubMed, Embase, and Medline databases in April 2022. The search included the following terms combined with Boolean operators: 'Meniscus repairs', 'Meniscal Repair', 'Posterior Horn', 'Root', 'Radial'. Inclusion criteria consisted of level I-IV human clinical and biomechanical studies reporting biomechanical data and/or outcomes following LMPR repair in the setting of ACLR.

RESULTS

Three biomechanical studies, all utilizing a transtibial pullout technique, were identified, all of which reported significant improvement in joint contact pressures and mechanics and 3/4 of which reported significant improvement in anterior or rotational stability with LMPR repair. Five clinical studies, consisting of 146 patients (mean age 28.5 ± 1.1 years) undergoing LMPR repair, were identified with an average follow-up of 19.1 months (range 6.2-46 months). Across all clinical studies, Lysholm and International Knee Documentation Committee (IKDC) scores were found to improve postoperatively, with 3/4 reporting significant improvement in Lysholm (all, p ≤ 0.001) scores and 3/5 reporting significant improvement in IKDC scores when compared to preoperative values (all, p ≥ 0.004). Meniscal extrusion decreased significantly following repair in 2/4 studies (all, p ≤ 0.001).

CONCLUSIONS

Biomechanically, transtibial pullout repair of the LMPR restored joint contact pressures and joint mechanics to intact levels when performed with concomitant ACLR. Clinically, LMPR repair with concurrent ACLR resulted in improved Lysholm and IKDC scores. These findings enable surgeons to determine optimal treatment plans and discuss realistic outcomes with patients when encountering LMPR injuries.

LEVEL OF EVIDENCE

IV.

Evaluation of the All-Inside Technique for the Repair of Lateral Meniscus Root Tears at 1 Year After ACL Reconstruction

Background

The presence of a lateral meniscus root tear (LMRT) in patients with an anterior cruciate ligament (ACL) tear makes the knee more unstable and increases the risk of osteoarthritis and osteonecrosis. An all-inside suture repair technique without bone tunnels has been proposed to treat LMRT.

Purpose

To compare the 1-year postoperative findings between patients who underwent ACL reconstruction combined with LMRT repair (LMRT group) and patients who underwent isolated ACL reconstruction (control group).

Study Design

Cohort study; Level of evidence, 3.

Methods

The LMRT group consisted of 19 patients, and the control group consisted of 56 patients. In this study, the authors compared the postoperative magnetic resonance imaging (MRI) findings (meniscal extrusion, ghost sign, and hyperintensity in the tibial plateau beneath the LMRT), functional outcomes (International Knee Documentation Committee [IKDC], Lysholm, and Tegner scores), and reoperation rate between groups. The primary endpoint was analyzed by comparing, in the LMRT group, the 1-sided 97.5% confidence interval (CI) of the mean lateral meniscal extrusion at 1 year to the limit of noninferiority (fixed at 0.51). To take into account imbalanced baseline characteristics between groups, adjusted mean meniscal extrusion (with 1-sided 97.5% CI) was assessed using a linear regression model.

Results

The mean follow-up was 12.2 months (range, 7.7-14.7 months) in the control group and 11.5 months (range, 7.1-13.0 months) in the LMRT group (P = .06). For meniscal extrusion, the LMRT group was noninferior to the control group. The mean meniscal extrusion was 2.19 mm (97.5% CI, -infinity to 2.68 mm) in the LMRT group and 2.03 mm (97.5% CI,-infinity to 2.27 mm) in the control group, indicating that the upper boundary of the 1-sided 97.5% CI in the LMRT group was less than the noninferiority threshold of 2.78 (ie, 2.27 mm + 0.51 mm = 2.78 mm). There was a statistically significant difference in the IKDC score between the LMRT and control groups (77.2 ± 8.1 vs 80.3 ± 7.3, respectively; P = .04). There was no between-group difference in the other MRI parameters, the Lysholm and Tegner scores, or the reoperation rate.

Conclusion

There was no significant difference in extrusion on MRI or clinical outcomes at 1-year follow-up in patients who underwent ACL reconstruction with all-inside LMRT repair compared with patients who did not have an LMRT.

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.

Meniscus tears treatment: The good, the bad and the ugly-patterns classification and practical guide

Over the years, several studies demonstrated the crucial role of knee menisci in joint biomechanics. As a result, save the meniscus has become the new imperative nowadays, and more and more studies addressed this topic. The huge amount of data on this topic may create confusion in those who want to approach this surgery. The aim of this review is to provide a practical guide for treatment of meniscus tears, including an overview of technical aspects, outcomes in the literature and personal tips. Taking inspiration from a famous movie directed by Sergio Leone in 1966, the authors classified meniscus tears in three categories: The good, the bad and the ugly lesions. The inclusion in each group was determined by the lesion pattern, its biomechanical effects on knee joint, the technical challenge, and prognosis. This classification is not intended to substitute the currently proposed classifications on meniscus tears but aims at offering a reader-friendly narrative review of an otherwise difficult topic. Furthermore, the authors provide a concise premise to deal with some aspects of menisci phylogeny, anatomy and biomechanics.

Posterior Horn Lateral Meniscal Oblique Radial Tear in Acute Anterior Cruciate Ligament Reconstruction Incidence and Outcomes After All-Inside Repair: Clinical and Second-Look Arthroscopic Evaluation

BACKGROUND

The term posterior horn lateral meniscal oblique radial tear (LMORT) has emerged to characterize the tear patterns of the lateral meniscus in many patients with acute anterior cruciate ligament (ACL) injury. There is a lack of data regarding the exact incidence according to the types of LMORT and clinical outcomes.

PURPOSES

(1) To investigate the incidence of LMORT according to type in patients with acute ACL reconstruction (ACLR) and (2) to identify healing status after repair of LMORT via second-look arthroscopy and clinical outcomes.

STUDY DESIGN

Case series; Level of evidence: 4.

METHODS

Patients who underwent primary ACLR within 6 months of injury were retrospectively reviewed. The LMORT was classified into 4 types based on the severity and distance from the root: type 1 (partial tear <10 mm from the root), type 2 (complete tear <10 mm from the root), type 3 (partial tear >10 mm from the root), type 4a (complete tear >10 mm from the root), and type 4b (type 4a with longitudinal tear at the meniscocapsular junction). Only patients with LMORT were isolated, and the clinical outcomes were compared according to the healing status of LMORT in second-look arthroscopy.

RESULTS

Of 635 patients with ACLR, LMORT was identified in 97 patients (15.3%), and type 4 LMORT accounted for the largest proportion (n = 62; 32.6%) of 190 lateral meniscal tears. In 79 patients with LMORT who satisfied the 2-year follow-up period, all patient-reported outcomes (PROs), including the Lysholm (preoperative, 64.1; postoperative, 88.2) and International Knee Documentation Committee subjective (preoperative, 50.5; postoperative, 82.9) scores, were significantly improved (P < .001) 31.8 months postoperatively. Of the 61 patients who underwent second-look arthroscopy, 49 (80.3%) were classified into the complete healing group. There was no significant difference in postoperative PROs between the complete and partial healing groups.

CONCLUSION

The incidence of LMORT was 15.3% in patients with acute ACL injury, and type 4 LMORT was the most common type. Complete healing of LMORT was achieved in 80.3% of patients who underwent second-look arthroscopy, and the PROs were significantly improved postoperatively. Good clinical results can be achieved if the LMORT is repaired as much as possible during ACLR.

An Arthroscopic Pull-Out Suture Technique to Repair Incomplete Radial Tears of the Lateral Meniscus Posterior Horn Adjacent to the Root Attachment Combined With Anterior Cruciate Ligament Reconstruction

Radial tears of the lateral meniscus posterior horn are one of the most common lateral meniscal injuries accompanied by acute anterior cruciate ligament disruption. Meniscus-preserving therapy is recommended in the case of a radial lateral meniscal tear to preserve its dynamic behavior. We introduce an arthroscopic pull-out technique for repairing incomplete radial tears of the lateral meniscus posterior horn combined with anterior cruciate ligament reconstruction. In this technique, a ring hoop is made through which the tear ends of lateral meniscus on both sides are tightened by adjusting tension of stitches, providing annular and downward tension for lateral meniscus, both of which are critical to the stability of the lateral meniscus. The resident part of lateral meniscus adjacent to the posterior root is not subject to much tension in this technique because of the pull-out fixation of lateral meniscus posterior horn, thus providing support for healing and restoring the hoop action of the lateral meniscus.

Anterior Tibial Subluxation of Lateral Compartment Is Associated With High-Grade Rotatory Instability for Acute But Not Chronic Anterior Cruciate Ligament Injuries: An Magnetic Resonance Imaging Case-Control Study

PURPOSE

To investigate whether anterior tibial subluxation obtained from magnetic resonance imaging (MRI) could be a predictor of high-grade rotatory instability for anterior cruciate ligament (ACL) injuries, including acute and chronic cases.

METHODS

From September 2016 to August 2018, we retrospectively investigated 163 patients with ACL injuries who subsequently underwent primary ACL reconstruction. Among them, 30 patients with high-grade rotatory instability (grade II/III pivot shift) were included in the high-grade group, and their age and sex were matched 1:2 to low-grade cases (<grade II pivot shift). On preoperative MRI, we measured anterior tibial subluxation, posterior tibial slope, as well as the time from injury to surgery. Meniscal lesions were documented from arthroscopy. Multivariable logistic regression was used to determine predictors of high-grade rotatory instability. Furthermore, subgroup comparisons between 2 groups were divided into acute (≤3 months) and chronic (>3 months) phases.

RESULTS

The high-grade group had a larger anterior tibial subluxation of lateral compartment (8.1 mm vs 5.9 mm; P =.004) than the low-grade group, whereas no significant difference was found in anterior tibial subluxation of medial compartment (P > .05). Moreover, high-grade anterior tibial subluxation of lateral compartment (≥6 mm) was found to be an independent predictor (odds ratio, 12.992; P = .011) associated with concomitant meniscal tears after ACL injuries. Anterior tibial subluxation of lateral compartment demonstrated statistical significance between the two groups when comparing subgroups within 3 months but not beyond 3 months.

CONCLUSION

In ACL-injured patients, high-grade anterior tibial subluxation of lateral compartment (≥6 mm) could be a unique predictor of high-grade knee rotatory instability for acute but not chronic injuries. Prolonged time from injury to surgery and lateral meniscus tears were risk factors for high-grade rotatory laxity in chronic patients.

LEVEL OF EVIDENCE

Level III, retrospective prognostic trial.

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.

Clinical significance and management of meniscal extrusion in different knee pathologies: a comprehensive review of the literature and treatment algorithm

The menisci are crescent-shaped, fibrocartilaginous structures that play a crucial role in the load transition and distribution of the contact forces along the tibiofemoral articulation. Meniscal extrusion (ME) is a radiological finding, especially in magnetic resonance imaging (MRI) scans, for which there has been growing interest in recent years. ME, in the coronary plane, is defined as the maximum distance of the most distal end of the meniscus from the border of the tibial plateau, where the tibial eminences are the most prominent, without taking into account the osteophytes. Although there is still controversy in the literature in respect of the optimal cutoff value, a threshold of 3 mm is considered significant. ME has no specific clinical finding or sign and it is encountered in many knee pathologies. It is associated with either rapidly progressive knee osteoarthritis or early onset of knee osteoarthritis and increased morbidity. In this review, we delineate the clinical significance of ME in various knee pathologies, as well as when, why and how it should be managed. To the best of our knowledge, this is the first study to elaborate on these topics.

An All-Inside Repair Technique for Unstable Type-IV Lateral Meniscal Posterior Root Tear

Lateral meniscal posterior root tears are defined as tears of meniscus within 9 mm from the bony root attachment. Unrepaired root tears significantly compromise the biomechanical functions of the meniscus, resulting in early and accelerated osteoarthritis. Several authors have described various techniques to reattach the posterior root of the lateral meniscus, and decent short-term results have been observed. Although most previous techniques are capable of repairing radial root tears, difficulties are encountered when repairing oblique type IV tears. In this technique note, the author describes an efficient side-to-side repair technique using the FAST-FIX system, which is practical in repairing the type IV tears of the lateral meniscus. This technique includes certain sequence of the stitches and skills of controlling the root remnant, which makes it easy to penetrate the meniscus and to achieve anatomic repair.

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.

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.

Meniscal Root Repair Alone or Combined with Different Procedures After at Least 6 Months of Follow-Up: A Series of Cases

Purpose

To analyze clinical and functional outcomes of patients submitted to posterior meniscal root repair of the medial or lateral meniscus in different settings, with at least 6 months of follow-up.

Patients and Methods

Retrospective multicentric study assessing epidemiological characteristics and clinical-functional results of 22 patients who underwent meniscal root reinsertion (MRR) by transtibial technique. This study addressed different settings: isolated medial root repair, medial root repair associated with high tibial osteotomy (HTO) and lateral root repair associated with anterior cruciate ligament (ACL) reconstruction.

Results

Twelve patients had an isolated tear of the posterior root of the medial meniscus and underwent MRR alone. Six patients had a varus axis >5°, undergoing MRR in addition to HTO in the same surgical procedure. Four patients underwent repair of the posterior root of the lateral meniscus associated with simultaneous reconstruction of the ACL. The main results of the study were observed in the improvement of the IKDC score from 27.7% preoperatively to 69.8% in the postoperative period (p < 0.0001) and the Lysholm score of 44.4 points preoperatively to 88.4 points in the postoperative period (p < 0.0001). Significant clinical and subjective improvements were also reported.

Conclusion

Medial meniscal root repair, associated or not with valgus tibial osteotomy (when indicated) and lateral meniscal root repair associated with ACL reconstruction, improved clinical, functional, and subjective results of the patients presented in this case series in the short term.

Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use:

https://youtu.be/8gGBDD95OIg

[Posterior meniscus root tears]

Meniscus root tears are radial tears in the region of the posterior insertion zones. Medial root injuries usually occur in individuals > 50 years of age without adequate trauma and are associated with obesity and varus deformities. The root lesion leads to a loss of ring tension, which results in extrusion of the meniscus and a strong increase in joint pressure that is biomechanically equivalent to a complete meniscectomy. When indicating arthroscopic transosseous refixation of the medial root lesion, factors such as accompanying cartilage damage, osteoarthritis, obesity and varus deformity must be taken into account. Injuries to the root of the lateral meniscus are mostly observed in younger patients in combination with a rupture of the anterior cruciate ligament. Arthroscopic transosseous refixation in combination with cruciate ligament surgery is therefore also recommended for type I and type II lesions. In summary, both the medial and the lateral root lesions of the menisci are injuries with high biomechanical relevance.

Quantifying the differential functional behavior between the medial and lateral meniscus after posterior meniscus root tears

Meniscus tears of the knee are among the most common orthopedic knee injury. Specifically, tears of the posterior root can result in abnormal meniscal extrusion leading to decreased function and progressive osteoarthritis. Despite contemporary surgical treatments of posterior meniscus root tears, there is a low rate of healing and an incidence of residual meniscus extrusion approaching 30%, illustrating an inability to recapitulate native meniscus function. Here, we characterized the differential functional behavior of the medial and lateral meniscus during axial compression load and dynamic knee motion using a cadaveric model. We hypothesized essential differences in extrusion between the medial and lateral meniscus in response to axial compression and knee range of motion. We found no differences in the amount of meniscus extrusion between the medial and lateral meniscus with a competent posterior root (0.338mm vs. 0.235mm; p-value = 0.181). However, posterior root detachment resulted in a consistently increased meniscus extrusion for the medial meniscus compared to the lateral meniscus (2.233mm vs. 0.4705mm; p-value < 0.0001). Moreover, detachment of the posterior root of the medial meniscus resulted in an increase in extrusion at all angles of knee flexion and was most pronounced (4.00mm ± 1.26mm) at 30-degrees of knee flexion. In contrast, the maximum mean extrusion of the lateral meniscus was 1.65mm ± 0.97mm, occurring in full extension. Furthermore, only the medial meniscus extruded during dynamic knee flexion after posterior root detachment. Given the differential functional behaviors between the medial and lateral meniscus, these findings suggest that posterior root repair requires reducing overall meniscus extrusion and recapitulating the native functional responses specific to each meniscus.