Safe bearing region for avoiding meniscal bearing impingement and overhang in mobile-bearing unicompartmental knee arthroplasty

The purposes of this study were to propose a quantitative method of bearing overhang to minimize the effect of bearing spinning on mobile-bearing unicompartmental knee arthroplasty (MB UKA), suggest and apply safe bearing regions in daily activities. The overhang distance and area were calculated for neutral and spinning positions. The safe bearing regions were based on the relationship between bearing overhang and linear wear rate. Eleven patients were included in an in-vivo experiment under dual fluoroscopic imaging following medial MB UKA. The bearing position was tracked by minimal joint space width, and the bearing overhang was calculated accordingly. Due to an equal contribution of 1 mm increase in medial overhang and 30 mm2 overhang areato wear rate, the maximum effect of potential bearing spinning on medial overhang distance was approximately three times as large as the overhang area. The safe bearing distance and area regions were rectangles and arches with different scales for different size combinations of bearing, femoral and tibial components. The maximum bearing overhang area during lunge (R = 0.76, p = 0.006) and open-chain exercise (R = 0.68, p = 0.02) significantly correlated with the overhang area in standing. The overhang area can be an appropriate parameter for evaluating dislocation degree less affected by potential bearing spinning than the overhang distance in clinical practice. The corresponding safe overhang area regions were proposed for surgical planning and postoperative dislocation degree evaluation. The bearing overhang area in static standing posture can be a valuable reference to estimate the dynamic overhang area and dislocation degree during motion.

Radial and longitudinal meniscus tears show different gapping patterns under stance phase conditions

Meniscal tearing can increase the contact pressure between the tibia and femur by causing gapping of torn meniscus tissue. The aim of this study was to quantify gapping behavior of radial and longitudinal tears and their impact on peak contact pressure and mean contact area. Twelve porcine knee joints underwent unicondylar, convertible osteotomy for exact tear application and consecutive suturing. Six tantalum marker beads were positioned along meniscus tears. The joints were preloaded with sinusoidal loading cycles ranging between 0 N and 350 N. Peak load was held constant and two synchronized Roentgen stereophotogrammetric analysis x-ray images were obtained to evaluate gapping, peak contact pressure and mean contact area in the native, torn and repaired states. There was no change in gapping or peak contact pressure in longitudinal tear. By contrast, the radial tear led to a significant gapping when compared to the native state, while the inside-out suture was able to restore gapping in parts of the meniscus. An increase in contact pressure after radial tear was detected, which was again normalized after suturing. The most important finding of the study is that longitudinal tears did not gap under pure axial loading, whereas radial tears tended to separate the tear interfaces.

Anterior Cruciate Ligament Rupture Combined with Complete Radial Tear of the Posterior Horn of the Lateral Meniscus: Suture or Resection?

Anterior cruciate ligament (ACL) rupture often presents with a tear of the posterior horn of the lateral meniscus. There is no clear preference between ACL reconstruction with suture and resection of the meniscus. We aimed to compare the clinical efficacy of ACL reconstruction with suture versus resection in patients presenting with arthroscopic ACL rupture and radial complete tear of the posterior corner of the lateral meniscus. We retrospectively analyzed 157 patients with ACL rupture and complete radial tear of the posterior horn of the lateral meniscus. Between May 2010 and April 2015, 86 of 157 patients underwent ACL reconstruction and meniscus suture (study group, 54.78%) and 71 of 157 patients underwent ACL reconstruction and meniscus resection (control group, 45.22%) in our department. All patients were monitored over the 12 to 72-month follow-up period. The primary evaluation indices were the Lysholm scores, the International Knee Documentation Committee (IKDC) scores, pivot shift test, the Barret criteria, and magnetic resonance imaging (MRI) findings of meniscal healing. The majority of 157 patients were relatively young men (29.64 ± 7.79 years) with low body mass index (BMI) (23.79 ± 2.74). The postoperative Lysholm and IKDC scores of the two groups were significantly improved over the corresponding preoperative scores (p < 0.05). The clinical results and excellent and good rates were significantly better for the study group than for the control group (both, p < 0.05). MRI showed that the meniscal healed rate of the study group was 96.51%. There was no significant difference in BMI between subgroups for any functional outcome. For patients with ACL rupture and complete radial tear of the posterior horn of the lateral meniscus, ACL reconstruction and both simultaneous suture and resection of the posterior horn of the lateral meniscus were found to be safe and effective. There was no association between outcomes and BMI. However, the former was associated with a superior long-term clinical effect and may restore the integrity of the meniscus and is particularly recommended for young patients.

Medial meniscus extrusion during gait is associated with decrease in knee rotation in early-stage knee osteoarthritis

BACKGROUND

In patients with medial knee osteoarthritis (OA), medial meniscus extrusion during gait is aggravated by mechanical stress, such as knee adduction moment (KAM). Conversely, the decrease in the range of knee rotation during stance phase is also one of the important issues in early knee OA, whereas the correlation between medial meniscus extrusion and knee rotation during gait are unclear.

RESEARCH QUESTION

To investigate the correlation between increase in medial meniscus extrusion and range of knee rotation during gait in patients with early- and late-stage of knee OA.

METHODS

Forty patients with medial knee OA were enrolled and divided into early- and late-OA group by Kellgren-Lawrence grading scale. During gait tasks, the extent of medial meniscus extrusion was measured using ultrasonography and kinetic/kinematic data were measured using three-dimensional motion analysis system. The correlation between medial meniscus extrusion and the range of knee rotation or KAM were evaluated in the overall, early-, and late- OA groups.

RESULTS

A significant negative correlation was observed between an increase in medial meniscus extrusion and range of knee rotation angle in early-OA group only. However, an increase in medial meniscus extrusion significantly correlated with the second KAM peak in the overall and early-OA groups.

SIGNIFICANCE

The decrease in range of knee rotation during stance phase may be associated with the increase in medial meniscus extrusion during gait in patients with early knee OA.

Arthroscopic inferior leaf meniscectomy of the involved anterior horn in the lateral meniscus horizontal tear via an accessary extreme far anteromedial portal

BACKGROUND

An accessory extreme far anteromedial portal can improve visualisation and ease inferior leaf meniscectomy in patients with lateral meniscal anterior horn horizontal tears. However, the therapeutic outcomes of adding an accessory extreme far anteromedial portal remain unclear. This study aimed to evaluate the clinical efficacy of adding an accessory extreme far anteromedial portal for treating lateral meniscal horizontal tears involving the anterior horns.

METHODS

This retrospective study included 101 patients with anterior horn involvement in lateral meniscal horizontal tears who underwent arthroscopic unstable inferior leaf meniscectomy between January 2016 and December 2020. The pathologies were diagnosed using physical examinations and magnetic resonance imaging. The anterior horn involved in the lateral meniscal horizontal tears was treated using inferior leaf meniscectomy. The primary endpoints were changes in the visual analogue scale, Lysholm, International Knee Documentation Committee, and Tegner scores at the final follow-up. The secondary endpoint was meniscal cure rate at 3 months postoperatively. The preoperative and postoperative functional scores were compared. The occurrence of complications was recorded.

RESULTS

All patients were followed up for an average of 4.9 ± 1.2 years (range 2.3-7.5 years). After 4 months, none of the patients experienced pain, weakness, instability, or tenderness in the lateral joint line, achieving an imaging cure rate of 98%. At the final follow-up, significant postoperative improvements were observed in the average values of the visual analogue scale score (3.5 ± 0.7 vs. 0.7 ± 0.6), Lysholm score (62.7 ± 4.4 vs. 91.8 ± 3.1), International Knee Documentation Committee score (61.9 ± 3.7 vs. 91.7 ± 9.5), and Tegner score (2.0 ± 0.7 vs. 6.1 ± 0.7). Excellent Lysholm scores were obtained in 81 patients, and good outcomes were obtained in 18 patients, with an excellent-to-good rate of 98.0%.

CONCLUSIONS

Inferior leaf resection via the accessory far anteromedial portal is a safe treatment option for the involved anterior horn in lateral meniscal horizontal tears. This approach enhances visibility and facilitates surgical procedures, with minimal complications.

Reconstruction of medial meniscus posterior portion deficiency in pigs with an autologous patellar tendon graft: an experimental study

OBJECTIVE

This study was performed to investigate the effectiveness of two surgical procedures, autologous patellar tendon graft reconstruction and trans-tibial plateau pull-out repair, using a pig model. The primary focus was to assess the repair capability of medial meniscus posterior portion (MMPP) deficiency, the overall structural integrity of the meniscus, and protection of the femoral and tibial cartilage between the two surgical groups. The overall aim was to provide experimental guidelines for clinical research using these findings.

METHODS

Twelve pigs were selected to establish a model of injury to the MMPP 10 mm from the insertion point of the tibial plateau. They were randomly divided into three groups of four animals each: reconstruction (autologous tendon graft reconstruction of the MMPP), pull-out repair (suture repair of the MMPP via a trans-tibial plateau bone tunnel), and control (use of a normal medial meniscus as the negative control). The animals were euthanized 12 weeks postoperatively for evaluation of the meniscus, assessment of tendon bone healing, and gross observation of knee joint cartilage. The tibial and femoral cartilage injuries were evaluated using the International Society for Cartilage Repair (ICRS) grade and Mankin score. Histological and immunohistochemical staining was conducted on the meniscus-tendon junction area, primary meniscus, and tendons. The Ishida score was used to evaluate the regenerated meniscus in the reconstruction group. Magnetic resonance imaging (MRI) was used to evaluate meniscal healing.

RESULTS

All 12 pigs recovered well after surgery; all incisions healed without infection, and no obvious complications occurred. Gross observation revealed superior results in the reconstruction and pull-out repair groups compared with the control group. In the tibial cartilage, the reconstruction group had ICRS grade I injury whereas the pull-out repair and control groups had ICRS grade II and III injury, respectively. The Mankin score was significantly different between the reconstruction and control groups; histological staining showed that the structure of the regenerated meniscus in the reconstruction group was similar to that of the original meniscus. Immunohistochemical staining showed that the degree of type I and II collagen staining was similar between the regenerated meniscus and the original meniscus in the reconstruction group. The Ishida score was not significantly different between the regenerated meniscus and the normal primary meniscus in the reconstruction group. MRI showed that the MMPP in the reconstruction and pull-out repair groups had fully healed, whereas that in the control group had not healed.

CONCLUSION

Autologous patellar tendon graft reconstruction of the MMPP can generate a fibrocartilage-like regenerative meniscus. Both reconstruction and pull-out repair can preserve the structural integrity of the meniscus, promote healing of the MMPP, delay meniscal degeneration, and protect the knee cartilage.

Collagen Meniscal Scaffold Implantation Can Provide Meniscal Regeneration in Asian Patients with Partial Meniscal Defects: A Prospective Randomized Controlled Study with Three-Dimensional Volume Analysis of the Meniscus

Background

To date, the efficiency of collagen meniscal scaffold implantation in Asian patients with partial meniscal defects has not been evaluated. In addition, no study has quantitatively analyzed meniscal regeneration using three-dimensional (3D) volume analysis after collagen scaffold implantation. We aimed to compare meniscal regeneration using 3D volume analysis between Asian patients undergoing collagen-based meniscal scaffold implantation after partial meniscectomy and those undergoing only partial meniscectomy.

Methods

Nineteen patients who underwent collagen-based meniscal scaffold implantation and 14 who underwent partial meniscectomy were analyzed with a prospective randomized control design for 12 months postoperatively. The demographic characteristics, Kellgren-Lawrence grade, and location of the injury lesion (medial or lateral meniscus) were not significantly different between the groups. Using 3D volume analysis with magnetic resonance imaging (MRI), the meniscus-removing ratio during the operative procedure and the meniscus defect-filling ratio were measured during the 12-month postoperative period. Clinically, the visual analog scale, International Knee Documentation Committee score, and Knee Injury and Osteoarthritis Outcome Score were evaluated. The Whole-Organ Magnetic Resonance Imaging Score (WORMS) and Genovese grade were also evaluated using MRI.

Results

In the 3D volume analysis, the average meniscus-removing ratio during surgery was not significantly different between the groups (-9.3% vs. -9.2%, p = 0.984). The average meniscus defect-filling ratio during the postoperative 12-month period was 7.5% in the scaffold group and -0.4% in the meniscectomy group (p < 0.001). None of the clinical results were significantly different between the scaffold and meniscectomy groups at 12 months postoperatively. The average change in the total WORMS score was not significantly different between the groups (0 vs. 1.9, p = 0.399). The Genovese grade of the implanted collagen scaffold did not significantly change during the follow-up period in terms of morphology and size (p = 0.063); however, the grade significantly improved in terms of signal intensity (p = 0.001).

Conclusions

Definite meniscal regeneration and stable scaffold incorporation were observed after collagen-based meniscal scaffold implantation in Asian patients during 12 months of follow-up. A long-term follow-up study with a larger cohort is required to determine the advantages of collagenous meniscal scaffold implantation in Asian patients.

Surgical Management of a Torn ACL and Bucket-Handle Meniscal Tear in the Pregnant Patient: A Case Report

CASE

A 36-year-old, 7-month pregnant woman presented to the office with a locked knee and a displaced bucket-handle medial meniscus tear, in the setting of chronic anterior cruciate ligament (ACL) insufficiency. After thorough discussion with the patient and her husband, the obstetrician, and the anesthesiologist, the patient was treated with left knee ACL reconstruction and medial meniscus repair.

CONCLUSION

With sufficient preoperative planning and coordinated multidisciplinary care among orthopaedic, anesthesiologist, and obstetric specialists, elective knee surgery can be performed safely in time-sensitive situations during pregnancy.

"Ring-shaped" meniscus and accompanying intermeniscal bridge meniscus: a rare combined variant resembling a bucket-handle tear

Many anatomical variations have been described in the menisci, especially in the lateral meniscus. Among these, discoid meniscus is the most common variation. Others are described in the literature as double-layered meniscus, accessory meniscus, ring-shaped meniscus, and hypoplastic meniscus. Also, combined variations associated with ring-shaped meniscus have been described, and they can be confused with fragmented complex tears and cause unnecessary surgery. Increasing awareness of the imaging features of these accompanying combined variations may aid in the recognition and differentiation of this entity from meniscus tears. We report the case of a ring-shaped meniscus and accompanying intermeniscal bridge meniscus, which has not been described before in the literature, highlighting the MRI and arthroscopic imaging findings of it.

Meniscus root tears: state of the art

BACKGROUND

Meniscus root tears represent significant pathology that, historically, has been underdiagnosed and undertreated. However, the recognition of their clinical and functional significance has recently surged, mainly due to their frequent association with anterior cruciate ligament injuries.

AIM

This comprehensive review discusses various aspects of meniscal root tears, including their epidemiology, biomechanics, etiology, clinical and radiological findings, classification, management and surgical techniques.

Clinical and radiologic outcomes in patients with meniscal root tears

BACKGROUND

Meniscal root tears can lead to early knee osteoarthritis and pain. This study aimed (1) to compare clinical and radiological outcomes between patients who underwent arthroscopic meniscal root repair after meniscal root tears and those who received non-surgical treatment, and (2) to identify whether baseline MRI findings could be potential predictors for future treatment strategies.

METHODS

Patients with meniscal root tears were identified from our picture archiving and communication system from 2016 to 2020. Two radiologists reviewed radiographs and MRI studies using Kellgren-Lawrence (KL) grading and a modified Whole Organ MRI Scoring (WORMS) at baseline and follow-up. The median (interquartile range [IQR]) of follow-up radiographs and MRI studies were 134 (44-443) days and 502 (260-1176) days, respectively. MR images were assessed for root tear-related findings. Pain scores using visual analogue scale (VAS) and management strategies (non-surgical vs. arthroscopic root repair) were also collected. Chi-squared tests and independent t-tests were used to assess differences regarding clinical and imaging variables between treatment groups. Logistic regression analyses were performed to evaluate the associations between baseline MRI findings and each future treatment.

RESULTS

Ninety patients were included. VAS pain scores were significantly (p < 0.01) lower after arthroscopic repair compared to conservative treatment (1.27±0.38vs.4±0.52) at the last follow-up visit with median (IQR) of 325 (180-1391) days. Increased meniscal extrusion (mm) was associated with higher odds of receiving non-surgical treatment (OR = 1.65, 95%CI 1.02-2.69, p = 0.04). The odds of having arthroscopic repair increased by 19% for every 1 mm increase in the distance of the tear from the root attachment (OR = 1.19, 95% CI: 1.05-1.36, p < 0.01). The odds of undergoing arthroscopic repair were reduced by 49% for every 1 mm increase in the extent of meniscal extrusion (OR = 0.51, 95% CI: 0.29-0.91, p = 0.02) as observed in the baseline MRI.

CONCLUSIONS

Patients who underwent arthroscopic repair had lower pain scores than patients with conservative treatment in the follow-up. Distance of the torn meniscus to the root attachment and the extent of meniscal extrusion were significant predictors for arthroscopic repair in the next three weeks (time from the baseline MRI to the surgery date).

Retrospective evaluation of MRI findings in arthroscopically confirmed cases of hypermobile lateral meniscus

OBJECTIVE

To identify preoperative MRI findings in patients with arthroscopically confirmed hypermobile lateral meniscus utilizing a standard MRI knee protocol, with comparison to normal control and lateral meniscal tear groups.

SUBJECTS AND METHODS

All patients with arthroscopically confirmed hypermobile lateral meniscus diagnosed at our institution were retrospectively identified. The following structures were evaluated on preoperative knee MRIs: superior and inferior popliteomeniscal fascicles, lateral meniscus and meniscocapsular junction, popliteal hiatus, and soft tissue edema around the popliteal hiatus. The same MRI features were evaluated in the normal control and lateral meniscal tear groups.

RESULTS

Study, normal control, and lateral meniscal tear patients (18 each) were included. In the study group, 94.4% had superior popliteomeniscal fascicle abnormality, 89.0% had inferior popliteomeniscal fascicle abnormality, and 72.2% had lateral meniscal abnormality. Incidence of these abnormalities was significantly higher than in the normal control group. Meniscal abnormalities in the study group all involved the posterior horn meniscocapsular junction, 12/13 of which had vertical signal abnormality at the junction and 1/13 with anterior subluxation of the entire posterior horn. Popliteus hiatus measurements were largest in the lateral meniscal tear group.

CONCLUSION

In patients with hypermobile lateral meniscus, the combination of popliteomeniscal fascicle abnormality and vertical signal abnormality at the meniscocapsular junction was seen in the majority of patients. Popliteomeniscal fascicle signal abnormality without identifiable lateral meniscal injury was the next most common imaging appearance. Radiologists may provide valuable information by suggesting the diagnosis of hypermobile lateral meniscus in such cases.

Arthroscopic Linear Chain Fixation for the Treatment of Medial Meniscus Posterior Root Tear: A Case Study

BACKGROUND

The repair and reconstruction of medial meniscus posterior root tears (MMPRTs) is an important issue in the field of orthopedic sports medicine. This study reports the first application of arthroscopic linear chain fixation for the treatment of MMPRTs.

CASE PRESENTATION

A 78-year-old female patient presented with a 1.5-month history of right knee pain accompanied by a locked facet joint. The patient underwent surgery with the new linear chain fixation method. In this method, the suture and the loop part of the buckle-strap titanium plate were combined into a linear chain mechanical complex, and the tension of the posterior root stump was gradually increased by pulling on the two attachment lines at the external mouth of the tibial tunnel. The postoperative Lysholm score was 89, and the visual analogue scale score was 0.9, indicating a significant improvement in knee joint function. At the 7-month and 1-year post-surgery follow-up, physical and MRI examinations confirmed satisfactory healing of the MMPRTs.

CONCLUSION

This surgical approach offers several benefits, including a simplified instrumentation setup, preservation of natural anatomical structures, and reliable residual stump fixation. It has the potential for clinical implementation.

Identical clinical outcomes between neutral and classic targeted alignments after high tibial osteotomy in medial meniscus posterior root tear: a prospective randomized study

PURPOSE

This study aimed to compare the clinical and radiographic outcomes and arthroscopic findings after high tibial osteotomy (HTO) between neutral and classic targeted coronal alignments in patients with medial meniscus posterior root tears (MMPRTs).

METHODS

Ninety-eight patients with MMPRT were prospectively enrolled in the final cohort and randomized into two groups. Fifty-two patients with the targeted alignment through the Fujisawa point (60-62.5% of the entire tibial plateau width measured from the medial side) during HTO were included in group A, whereas 46 patients with the targeted alignment through the point at 50-55% of the tibial plateau width were included in group B. The clinical and radiographic outcomes and second-look arthroscopic findings were statistically compared for comprehensive assessments.

RESULTS

After a mean follow-up of 37.1 months, we found no significant differences between the two groups regarding the final Lysholm (p = 0.205) and Hospital for Special Surgery scores (p = 0.084). However, we only observed significant differences between the two groups in terms of the final hip-knee-ankle angle, weight-bearing line ratio, and medial proximal tibial angle (p < 0.001). Second-look arthroscopy did not reveal a significant difference in meniscal healing rate (p = 0.786).

CONCLUSIONS

Performing HTO with the aim to achieve neutral alignment leads to similar clinical outcomes in patients with MMPRT compared to classic alignment. Although subsequent research is required, the current study provides clinical evidence for the safety and efficacy of the new targeted alignment during HTO, which may avoid long-term complications associated with overcorrection when using the traditional technique.

Age-based comparison of meniscal dimensions between an asymptomatic complete discoid lateral meniscus and normal meniscus: MRI evaluation

INTRODUCTION

This study aimed to evaluate the meniscal size of asymptomatic discoid lateral meniscus (DLM) and compare it with that of normal lateral meniscus (LM) and to compare changes in meniscal dimensions with age among patients with asymptomatic DLM and those with normal LM using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We retrospectively reviewed the medical records, including MRI data, of patients with asymptomatic DLM (DLM group) or normal LM (control group). Width and extrusion of both DLM and normal LM and tibial length were measured and compared using mid-coronal and mid-sagittal MR images. Meniscal size and sagittal and coronal meniscal ratio according to age, as well as differences between DLM and normal menisci, were also evaluated.

RESULTS

Thirty-four knees were included in the DLM group, whereas the control group comprised of 50 patients. The DLM group showed significantly less meniscal extrusion, greater coronal width, posterior capsule distance, sagittal meniscal length, and sagittal meniscal ratio than the control group (DLM: 0.1 ± 0.3 mm, 23.3 ± 2.2 mm, 5.4 ± 2.4 mm, 25.1 ± 2.8 mm, 61 ± 6%, and control: 0.4 ± 0.4 mm, 9.5 ± 2.3 mm, 2.5 ± 1.2 mm, 30.2 ± 2.6 mm, 71 ± 4%, respectively). The coronal meniscal ratio decreased with age in both the control (p = 0.001) and DLM (p = 0.037) groups. The sagittal meniscal ratio (p = 0.001) and minimum height (p = 0.04) decreased and the anterior capsule distance (p = 0.035), posterior capsule distance (p = 0.026), and entire sagittal length (p = 0.005) increased with age in the DLM group, while the distance between the meniscal inner margins (p = 0.019) increased with age in the control group.

CONCLUSIONS

The meniscal ratio in the sagittal plane of the DLM group was significantly lower than that of the control group. The sagittal meniscal ratio of asymptomatic DLM decreased with age, indicating that the size of asymptomatic DLM does not change with age.

LEVEL OF EVIDENCE

III: Retrospective comparative study.

Two years follow-up of patients with knee varus deformity and medial meniscus extrusion after medial opening wedge high tibial osteotomy and arthroscopic meniscus centralization

PURPOSE

This is a retrospective study and aims to investigate the clinical outcomes of patients with knee varus deformity and extruded medial meniscus who underwent arthroscopic meniscus centralization and medial opening wedge high tibial osteotomy.

METHODS

A total of 24 patients were included in the trial, and arthroscopy intraoperative photographs and standing preoperative and postoperative radiographs were taken to analyze the mechanical tibiofemoral angle and tibial plateau inclination. Postoperative complications and knee motion were recorded, and the surgical results were evaluated using the knee society score.

RESULTS

The study observed four cases of surgery-related complications among all patients, but no major complications were reported. The surgery significantly improved knee flexion degrees and total knee range of motion. Satisfactory outcomes were shown in postoperative radiographs and secondary intraoperative photographs. The knee score increased from 39.6 ± 10.0 to 80.1 ± 9.0, and the functional score improved from 48.1 ± 6.9 to 89.4 ± 5.5. The preoperative tibial plateau inclination was 5.3 ± 0.7, while the postoperative data showed a decrease to 4.2 ± 0.7. The preoperative mechanical tibiofemoral angle was - 7.7 ± 1.0, and it improved in all patients postoperatively to 2.8 ± 0.9.

CONCLUSION

By alternating the knee biomechanics and significantly improving symptoms and quality of life, arthroscopic medial meniscus centralization and medial open wedge high tibial osteotomy units are confirmed to be an effective alternative treatment for knee varus deformity.

Effect of residual volume after surgery of the discoid lateral meniscus on tibiofemoral joint biomechanics: a finite element analysis

BACKGROUND

The purpose of this study was to investigate the influence of different residual meniscus volume on the biomechanics of tibiofemoral joint after discoid lateral meniscus (DLM) surgery by finite element analysis.

METHODS

A knee joint model was established based on CT and MRI imaging data. The DLM model was divided into five regions according to conventional meniscectomy, with volumes of 15%, 15%, 15%, 15%, 15%, and 40% for each region. Additionally, the DLM model was divided into anterior and posterior parts to obtain ten regions. The DLM was resected according to the design scheme, and together with the intact discoid meniscus, a total of 15 models were obtained. Finite element analysis was conducted to assess shear and pressure trends on the knee joint.

RESULTS

The study observed significant changes in peak shear stress and compressive stress in the lateral meniscus and lateral femur cartilage. As the meniscus volume decreased, there was an increase in these stresses. Specifically, when the meniscus volume reduced to 40%, there was a sharp increase in shear stress (302%) and compressive stress (152%) on the meniscus, as well as shear stress (195%) and compressive stress (157%) on the lateral femur cartilage. Furthermore, the model grouping results showed that preserving a higher frontal volume in the meniscus model provided better biomechanical advantages.

CONCLUSION

The use of finite element analysis has demonstrated that preserving more than 55% of the meniscus volume is necessary to prevent a significant increase in joint stress, which can potentially lead to joint degeneration. Additionally, it is crucial to preserve the front volume of the DLM in order to achieve improved knee biomechanical outcomes.

Evaluation of Remodeling and Extrusion of Polyurethane Meniscal Implants after Meniscus Reconstruction using Ultrasonography

INTRODUCTION

Meniscal tears are among the most common indications for knee arthroscopy. Artificial polyurethane scaffolds have demonstrated efficacy in reducing pain and promoting the growth of normal meniscal tissue, with high absorption rates facilitating full tissue regeneration.

AIMS

This study aimed to evaluate the remodeling of polyurethane meniscal implants post-reconstruction using ultrasonography. This imaging technique not only assesses changes in implant properties, such as echogenicity, but also the shape changes during functional examination.

METHODS

The assessment of meniscal extrusion, comparing size at rest and under weight-bearing, is an indirect parameter that provides insight into the physical properties of the remodeling implant, with greater extrusion indicating reduced stiffness and inferior physical properties of the meniscus. Ultrasonography has the valuable advantage of allowing for assessment of the blood supply to the meniscus through Power Doppler imaging.

RESULTS

The presence of vessels within the meniscal implants serves as evidence of ongoing remodeling. The study included 35 patients (13 female, 22 male; mean age 41.6 years, range 18-66) who underwent arthroscopic meniscal reconstruction with polyurethane implants, with an average time from surgery of 2.8 years (range 0.3-4.5 years). Results showed complete (29.7%), significant (45.9%), or moderate (16.2%) remodeling into natural meniscal tissue in 91.8% of the implants.

CONCLUSION

The mean values of extrusion in the supine position and during 90-degree flexion were significantly greater in the operated limb (2.603) compared to the contralateral limb (1.978; t(35) = 2.442; P < 0.05). No significant differences in extrusion were found between the limbs in a standing position, indicating favorable physical properties of the polyurethane meniscal implants. Further ultrasonography studies of meniscal scaffolds are deemed relevant.

Mid-Term Clinical and Radiological Outcomes of Lateral Meniscal Allograft Transplantation with Suture-Only Fixation Plus Capsulodesis

Meniscal allograft transplantation (MAT) is an effective reconstructive procedure for treating a symptomatic postmeniscectomy syndrome. It consists of replacing the lost meniscal tissue aiming to improve the clinical outcomes and prevent progressive deterioration of the joint. The aim of this study was to evaluate meniscal graft survivorship and report on the radiographic (in terms of graft extrusion and joint space width and alignment) and the functional results through a midterm follow-up of lateral MAT performed with a soft tissue fixation technique after capsulodesis. In total, 23 patients who underwent lateral MAT as a single procedure were included. The Knee injury and Osteoarthritis Outcome Score, Lysholm, Tegner, and visual analog scale scales were used for patient assessment. Magnetic resonance imaging and a complete radiographic protocol were conducted to determine the degree of meniscal extrusion and the changes in the degree of osteoarthritis and coronal alignment. Assessments were performed after 2 and 7 years of follow-up. A significant improvement in all the scores, relative to preoperative values, was found after 7 years of follow-up. This improvement remained consistent throughout the first and second follow-up periods. A mean absolute extrusion of 2.2 mm ± 1.6 and an extrusion percentage of 28.0% ± 11.43 were found, with no significant differences throughout the follow-up periods. There was no statistically significant difference in terms of the frontal mechanical axis and joint space narrowing between the preoperative value and at the first and second follow-up periods. A survival rate of 85.7% was found after 7 years of follow-up. Capsulodesis results in a low degree of meniscal extrusion in isolated lateral MAT fixed with a suture-only technique, which is maintained after 7 years of follow-up, with a high graft survival index (>85%) and satisfactory results on the functional scales.

[Medial discoid meniscus in a pediatric patient. Case report and review of the literature]

Discoid meniscus is a congenital morphological variant of the meniscus, which tends to occur more frequently in its lateral form than in the medial form. This anomaly is characterized by central hypertrophy of the meniscus and a larger diameter than the normal meniscus, resulting in an abnormal shape and greater coverage of the tibial plateau. The clinical presentation of this condition varies depending on the stability of the meniscus. In pediatric patients, in particular, it is common to experience progressive and atraumatic symptoms, such as pain and limited mobility. Diagnosis is based on imaging studies, with magnetic resonance imaging being the preferred tool, where the "bowtie sign" is a classic finding. Surgery is recommended for symptomatic patients, with a focus on preserving the peripheral portion of the meniscus. Saucerization is the most commonly used technique, followed by stability assessment to determine if additional procedures are required. In this case, a 9-year-old patient with a medial discoid meniscus presented symptoms following trauma. Despite this atypical presentation, a successful outcome was achieved through arthroscopic surgery, underscoring the importance of accurate diagnosis and proper management of this condition in pediatric patients. Understanding the anatomical and pathophysiological characteristics of the discoid meniscus is essential for an effective therapeutic approach.

Intercondylar notch width and osteophyte width impact meniscal healing and clinical outcomes following transtibial pullout repair of medial meniscus posterior root tears

PURPOSE

This retrospective study aimed to investigate the relationship between intercondylar notch width (ICNW), osteophyte width (OW), and the healing of medial meniscus posterior root tears (MMPRTs) following arthroscopic pullout repair.

METHODS

The study included 155 patients diagnosed with MMPRTs who underwent transtibial pullout repair. Meniscal healing status was evaluated on second-look arthroscopy using a previously reported meniscus healing score. Patients were divided into two groups based on this score: the high healing score (group HH, healing score ≥ 8 points) and suboptimal healing score (group SO, healing score ≤ 6 points) groups. Computed tomography scans were performed on patients 1 week postsurgery. ICNW and OW widths were measured and relatively evaluated based on their ratio to the intercondylar distance (ICD), represented as the ICNW/ICD ratio (%) and OW/ICD ratio (%), respectively. Patient-reported outcomes were assessed preoperatively and on second-look arthroscopy using the Knee injury and Osteoarthritis Outcome Score (KOOS) and visual analogue scale (VAS).

RESULTS

There were no significant demographic differences between the SO and HH group (n = 35 and 120 patients, respectively). Regarding radiographic measurements, significant differences were observed in the ICNW/ICD ratio (group SO, 24.2%; group HH, 25.2%; p = 0.024), OW (group SO, 2.6 mm; group HH, 2.0 mm; p < 0.001), and OW/ICD ratio (group SO, 3.5%; group HH, 2.7%; p < 0.001). Both groups had similar preoperative clinical scores, but postoperative clinical scores, including KOOS-activities of daily living (group SO, 83.4; group HH, 88.7; p = 0.035) and VAS (group SO, 19.1; group HH, 11.3; p = 0.005), were significantly better in group HH.

CONCLUSION

The study suggests that ICNW and OW may play a crucial role in MMPRT healing following arthroscopic pullout repair, as evidenced by the worse clinical outcomes associated with a narrower ICNW and wider OW. These findings highlight the potential significance of ICNW and OW assessments when evaluating meniscal repair indications.

LEVEL OF EVIDENCE

Level III.

Ultrasonographic diagnosis of medial meniscus posterior root tear in early knee osteoarthritis: a comparative study

INTRODUCTION

This study aimed to detect medial meniscal posterior root tear (MMPRT) diagnostic methods with high sensitivity and specificity using dynamic ultrasonographic evaluation in patients with early knee osteoarthritis (OA) and demonstrate the usefulness of dynamic ultrasonographic medial meniscal extrusion (MME) evaluation in MMPRT diagnosis using a cutoff value.

MATERIALS AND METHODS

Between 2018 and 2020, a total of 120 patients were diagnosed with early knee OA using clinical and radiographic findings. Dynamic ultrasonographic evaluations and magnetic resonance imaging were performed in all patients, and 47 patients who had and 73 patients who did not have MMPRT were classified into the MMPRT and non-MMPRT groups, respectively. Age, sex, femorotibial angle, MME of knee extension and flexion, and MME at weight-bearing were compared between the two groups. Additionally, the sensitivity and specificity of significant ultrasonographic findings were calculated using a receiver operating characteristic (ROC) curve.

RESULTS

The MMEs under knee extension-flexion and weight-loading in the MMPRT group were significantly larger than those in the non-MMPRT group. ROC curve analysis for each ultrasonographic evaluation condition to diagnose MMPRT indicated that the sensitivity was 72-88% and the specificity was 66-85% when the cutoff values of MME under knee flexion at 0°, 90°, and weight-loading were set at 2.55 mm, 2.00 mm, and 3.55 mm, respectively. The highest sensitivity (88%) and specificity (85%) were exhibited upon > 2 mm MME at a knee flexion of 90° and were the most useful indicators for MME diagnosis.

CONCLUSIONS

Ultrasonographic MME evaluations for MMPRT diagnosis showed relatively high sensitivity and specificity in patients with early knee OA. Dynamic ultrasonographic MME evaluation may lead to appropriate additional examinations, early diagnosis, and intervention for MMPRT in patients with early knee OA.

Medial meniscus extrusion is invariably observed and consistent with tibial osteophyte width in elderly populations: The Bunkyo Health Study

We reported that the full-length width of medial tibial osteophytes comprising cartilage and bone parts correlates with medial meniscus extrusion (MME) in early-stage knee osteoarthritis (OA). However, no data exist on the prevalence of MME and its relationship with osteophytes in the elderly population. 1191 elderly individuals (females 57%; 72.9 years old on average) in the Bunkyo Health Study underwent standing plain radiograph and proton density-weighted MRI on knee joints. MRI-detected OA changes were evaluated according to the Whole-Organ Magnetic Resonance Imaging Score. A new method of assessing the cartilage and bone parts of osteophytes was developed using pseudo-coloring images of proton density-weighted fat-suppressed MRI. Most subjects showed Kellgren-Lawrence grade 1 or 2 radiographic medial knee OA (88.1%), MME (98.7%, 3.90 ± 2.01 mm), and medial tibial osteophytes (99.3%, 3.27 ± 1.50 mm). Regarding OA changes, MME was closely associated with the full-length width of medial tibial osteophytes (β = 1.114; 95% CI 1.069-1.159; p < 0.001) in line with osteophyte width (intraclass correlation coefficient, 0.804; 95% CI 0.783-0.823). Our data revealed that MME and medial tibial osteophytes are observed in the elderly and demonstrate that the degree of MME is consistent with the full-length width of medial tibial osteophytes, suggesting that osteophytes might be implicated in MME.

High tibial osteotomy is equally effective for varus malaligned knees with either virgin or wrecked medial meniscus: An age and gender-matched secondary analysis of a Francophone Arthroscopy Society Symposium

INTRODUCTION

Despite the growing concept of meniscal preservation, partial meniscectomy could be the definitive procedure in specific scenarios. And total meniscectomy was once before a frequent procedure, with current sequelae of degenerate knees. High tibial osteotomy (HTO) is an effective treatment for patients suffering from unicompartmental degenerative changes, and substantial deformities. However, it is yet to be answered, whether HTO is similarly effective in both post-meniscectomy knees and knees with not previously operated meniscus.

HYPOTHESIS

Outcomes of HTO is similar with or without previous history of total or subtotal meniscectomy.

METHODS

This study compared the clinical and radiological outcomes of 41 patients who received HTO and had no previous history of surgery in the ipsilateral knee (group I), and 41 age, and gender-matched patients who had meniscectomy surgery in the ipsilateral knee (group II). Preoperatively and postoperatively, all patients were clinically evaluated; the visual analogue scale scores, Tegner activity score, and the Western Ontario and Macmaster University scores were reported. Radiographically, osteoarthritis grade and pre- and postoperative parameters were reported, including hip-knee-ankle angle, femoral mechanical angle, medial proximal tibial angle, joint line convergence angle, proximal posterior tibial angle, and limb length discrepancy. Perioperative details and complications were reported.

RESULTS

A total of 82 patients were included; group I (n=41) and group II (n=41). The mean age was 51.18±8.64 (27-68) and 90.24% were male. The duration since the onset of symptoms was longer in group II vs. group I, 43.34±41.03 versus 38.07±36.11months respectively. No significant differences in the clinical evaluation between the two groups with a greater proportion of patients demonstrating moderate degenerative changes. Similar preoperative and postoperative radiographic parameters were reported, in group I, Δ HKA was 7.19±4.14 versus 7.65±3.16 in group II. Preoperative pain VAS scores were slightly higher in group II vs. group I, 79.23±26.35 vs. 76.31±24.45, respectively. However, postoperatively, the pain scores significantly improved in group I vs. group II, 22.84±3.65 vs. 41.69±17.33, respectively. Tegner activity scores and WOMAC scores were comparable between both groups preoperatively and postoperatively. Only the WOMAC function scores were better in group I when compared to group II, 26.13±25.84 versus 20.01±17.98. All patients returned to work at an average of 0.82±0.38months.

CONCLUSION

Knee preservation with high tibial osteotomy is equally effective in managing unicompartmental degenerative changes in varus malaligned knees with either no previous history of meniscal surgeries or where a meniscal sacrifice was inevitable, either with subtotal or total meniscectomy.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Factors associated with meniscus volume in knees free of degenerative features

OBJECTIVES

To explore factors that were associated with meniscus volume in knees free of radiographic osteoarthritis (OA) features and symptoms of OA.

METHODS

In the third Rotterdam Study cohort, clinical, radiographic, and magnetic resonance data were obtained at baseline (BL) and after 5 years of follow-up. Meniscus volumes and their change over time were calculated after semi-automatic segmentation on Magnetic Resonance Imaging. Knees with radiographic OA features (Kellgren and Lawrence>0) or clinical diagnosis of OA (American College of Rheumatology) at BL were excluded. Ten OA risk factors were adjusted in the multivariable analysis (generalized estimating equations), treating two knees within subjects as repeated measurements.

RESULTS

From 1065 knees (570 subjects), the average (standard deviation) age and Body mass index (BMI) of included subjects were 54.3 (3.7) years and 26.5 (4.4) kg/m2. At BL, nine factors (varus alignment, higher BMI, meniscus pathologies, meniscus extrusion, cartilage lesions, injury, greater physical activity level, quadriceps muscle strength, and higher age) were significantly associated with greater meniscus volume. Five factors (injury, meniscus pathologies, meniscus extrusion, higher age, and change of BMI) were significantly associated with meniscus volume loss.

CONCLUSIONS

Modifiable factors (varus alignment, BMI, physical activity level, and quadriceps muscle strength) and non-modifiable factors (higher age, injury, meniscus pathologies, meniscus extrusion, and cartilage lesions) were all associated with meniscus volume or meniscus volume loss over time.

Wrisberg variant of the lateral discoid meniscus in children: review of the literature and presentation of case series

INTRODUCTION

The Wrisberg variant of the discoid lateral meniscus is a very rare disorder and is characterized by the hypermobility and instability of the meniscus caused by the absence of its posterior tibial attachment, with only its meniscofemoral junction (Wrisberg's ligament) maintained, and inserted in the posterior horn of the meniscus. As a result, the posterior horn of the lateral meniscus is mobile; often subluxing into the joint.

MATERIALS AND METHODS

A total of eight skeletally immature patients with symptomatic Wrisberg variant of the discoid lateral meniscus were included in this study. Each knee was evaluated with MRI and arthroscopy. We graded unstable discoid menisci according to their discoid morphology (complete vs. incomplete), meniscal intra-substance degeneration, and the presence or absence of meniscal tears. All eight menisci were evaluated as degenerated with no meniscal tears. Five of them were evaluated as complete. Due to the severely degenerated meniscus, we considered it unnecessary to repair the detached posterior tibial ligament, so we performed a reshaping of the discoid meniscus, restoring a C-shape, excising the hypertrophied central part of the meniscus, and creating a posterior horn with a remaining rim of 6-8 mm. For evaluation of the knee function preoperatively and postoperatively we used the online International Knee Documentation Committee (IKDC) system. The purpose of this study is to emphasize the importance of MRI in identifying and revealing the unstable (Wrisberg variant) type of discoid meniscus in children.

RESULTS

The mean patient age at the time of surgery was 8.25 ± 2.91 years (range 5-13 years). The average follow-up was 3.75 ± 0.46 years (range 3-4) years. The mean preoperative IKDC score was 22.37 ± 1.50 (range 21-25) points. The mean postoperative IKDC score was 80.50 ± 1.77 (range 79-84) points.

CONCLUSIONS

MRI is a valuable tool in the evaluation of the shape, stability, and consistency of symptomatic discoid menisci. It is helpful for the detection of the unstable Wrisberg variant.

Assessment of Knee Menisci in Healthy Adults Using Shear Wave Elastography

OBJECTIVES

The aim of this study was to explore the application value of shear wave elastography in healthy adults with knee meniscus.

METHODS

One hundred adult subjects who underwent health checkups at our hospital from December 2022 to February 2023 were selected as research participants. Shear wave elastography was used to evaluate the periphery of the lateral and medial meniscus in both knees. To assess the mean differences in Young's modulus values between male and female groups, a one-way analysis of variance (ANOVA) and independent samples t-test were conducted. In addition, a Pearson correlation coefficient test was used to analyze the correlation between the elastic values of the meniscus and age, height, weight, and body mass index (BMI).

RESULTS

There were no significant differences in elastic values between the lateral meniscus of the left and right sides or between the medial meniscus of the left and right sides within the same gender group (P > .05). Stiffness values of the medial meniscus were higher in each gender group than those of the lateral meniscus (P < .01). Additionally, males demonstrated higher stiffness values than females (P < .01). As age increased, the Young's modulus of the meniscus increased significantly (r > .75, P < .01).

CONCLUSION

Shear wave elastography can serve as an adjunctive tool to aid in the assessment of knee meniscal elasticity.

Saucerization of complete discoid lateral meniscus is associated with change of morphology of the lateral femoral condyle and tibial plateau

PURPOSE

To determine the effect of saucerization surgery on knee joint morphology associated with a complete discoid lateral meniscus (DLM) using magnetic resonance (MR) imaging.

METHODS

This retrospective study included cases had undergone saucerization surgery for symptomatic DLM between 2007 and 2022. All cases were divided into two by age group: < 12 (U13) and > 13 (O13). The cases in the match group were randomly selected from preoperative cases in the O13 group matched with the age at the final follow-up (F/U) of cases in the U13 group. The following morphological parameters were evaluated using MR images preoperatively and at the final postoperative F/U in each group: anterior obliquity of the lateral tibial plateau (AOLTP), posterior obliquity of the lateral tibial plateau (POLTP), and the lowest point of the lateral femoral condyle (LPLFC). Each parameter was compared between the U13 preoperative (pre-OP) group and the O13 pre-OP group, the preoperative and final follow-up in the U13, and the U13 group at the final F/U and the match group preoperatively.

RESULTS

A total of 77 cases were evaluated. 31 cases were in the U13 pre-OP group and 46 were in the O13 pre-OP group. With a minimal F/U of 2 years, 27 cases in the U13 group and 36 in the O13 group were included. The mean F/U period was 4.6 years in the U13 group and 3.2 years in the O13 group. 32 cases were included in the match group. In the match group, the inclination of the POLTP was significantly larger (P = 0.042) and the LPLFC was more lateral (P = 0.0034) than at the final F/U in the U13 group.

CONCLUSIONS

Saucerization surgery for DLM in juvenile patients can prevent progression to the characteristic bone morphology DLM. These results could help the surgeon making the decision when the surgery would be performed for symptomatic DLM patients.

LEVEL OF EVIDENCE

Retrospective comparative study; level of evidence, 3.

Meniscal extrusion in knees with and without osteoarticular pathology: A systematic review of normative values and cut-offs for diagnostic criteria

BACKGROUND

Meniscus extrusion is crucial for the diagnosis and treatment of meniscal injury, but the literature on this topic has not yet been systematized. The purpose of this systematic review was to compare diagnostic methods and summarize the data of medial and lateral meniscal extrusion in knees with and without osteoarticular pathology.

METHODS

This systematic review was conducted according to the PRISMA 2020 statement. Searches were conducted on PubMed, EMBASE and Cochrane databases to identify studies that measured meniscal extrusion using magnetic resonance imaging (MRI) or ultrasound (US). Meniscal extrusion data was summarized as weighted mean for medial and lateral meniscus, and stratified according to the method of measurement (MRI or US) and presence of knee osteoarticular pathology.

RESULTS

A total of 26 studies were included in this review. Weighted mean values of meniscal extrusion were always higher for the medial than the lateral meniscus, regardless of the method of measurement. The medial meniscus extrusion was always higher in knees with osteoarticular pathology than those without. For the lateral meniscus extrusion, the mean values were higher in those knees without osteoarticular pathology. When classifying pathological meniscal extrusion with pre-defined cut-off values, the higher the cut-off used, the lower the percentage of knees classified as pathological meniscal extrusion.

CONCLUSIONS

The medial meniscus presents on mean higher extrusion and extrusion is higher in knees with osteoarticular pathology. Based on summary data, the most suitable cut-offs for pathological meniscal extrusion for both MRI and US seem to fall within >2 and >3 mm.

Arthroscopic pullout repair versus suture anchor repair for medial meniscus posterior root tear combined with high tibial osteotomy

BACKGROUND

The aim of this study was to compare the outcomes of pullout repair with a metal button and suture anchor repair for medial meniscus posterior root tears in patients undergoing high tibial osteotomy with varus alignment.

METHODS

Patients who underwent arthroscopic pullout repair (P group) and suture anchor repair (SA group) in combination with open-wedge high tibial osteotomy between 2018 and 2021 were retrospectively examined. Patients who received second-look arthroscopy at 1 year and at least 2 years of follow up were included. Structural healing (complete/partial or failed healing) and chondral lesions at the initial surgery and the second-look arthroscopy, radiographic parameters around the knee, Lysholm score, and Tegner activity scale (before and 2 years after surgery) were compared.

RESULTS

A total of 88 patients (68 women/20 men, mean age 61.1 ± 7.9 years old) were included in the analysis. Of these, 51 patients underwent pullout repair, while the other 37 underwent suture anchor repair. The SA group showed a significantly higher rate of complete healing (64.9%) than the P group (21.6%, P < 0.001). The Lysholm score significantly improved after surgery in both treatment groups. At the final follow up, the SA group had a significantly higher Lysholm score (89.6 ± 10.7) than the P group (80.9 ± 17.4, P = 0.011).

CONCLUSION

Arthroscopic suture anchor repair had superior healing status and Lysholm Score in comparison with pullout repair with a metal button, as it achieved better tension adjustment. This result is meaningful particularly when medial meniscus root repair and high tibial osteotomy are performed simultaneously.

Meniscectomy is associated with a higher rate of osteoarthritis compared to meniscal repair following acute tears: a meta-analysis

PURPOSE

Meniscal tears are common and may impair knee function and biomechanics. This meta-analysis compared meniscal repair versus resection in patients with symptomatic meniscal tears in terms of patient-reported outcomes measures (PROMs), joint width, surgical failure, and rate of progression to osteoarthritis (OA) at conventional radiography.

METHODS

This study was conducted according to the 2020 PRISMA statement. In August 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. Two reviewers independently performed the analysis and a methodological quality assessment of the included studies. All the clinical investigations which compared repair versus resection of meniscal tears were accessed.

RESULTS

Data from 20 studies (31,783 patients) were collected. The mean BMI was 28.28 ± 3.2 kg/m2, and the mean age was 37.6 ± 14.0 years. The mean time elapsed from injury to surgery was 12.1 ± 10.2 months and the mean medial joint width was 4.9 ± 0.8 mm. Between studies comparability at baseline was found in age, women, BMI, time from injury to surgery and length of the follow-up, PROMs, medial joint width, and stage of OA. The resection group demonstrated a greater Lysholm score (P = 0.02). No difference was found in the International Knee Documentation Committee (P = 0.2). Nine studies reported data on the rate of failures at a mean of 63.00 ± 24.7 months. No difference was found between the two groups in terms of persistent meniscal symptoms (P = 0.8). Six studies reported data on the rate of progression to total knee arthroplasty at a mean of 48.0 ± 14.7 months follow-up. The repair group evidenced a lower rate of progression to knee arthroplasty (P = 0.0001). Six studies reported data on the rate of advanced knee OA at a mean of 48.0 ± 14.7 months of follow-up. The repair group evidenced a lower rate of advanced knee OA (P = 0.0001). No difference was found in the mean joint space width (P = 0.09).

CONCLUSION

Meniscal repair is associated with a lower progression to knee osteoarthritis at approximately six years of follow-up compared to partial meniscectomy. No difference in PROMs, medial joint width, and failures were evidenced.

LEVEL OF EVIDENCE

Level III, meta-analysis.

Comparison of Size of Posterior Tibial Slope and Medial Tibial Depth in Patients With an Isolated Meniscal Tear Requiring Surgery and Matched Uninjured Controls

BACKGROUND

Meniscal injuries are extremely common. Several anatomic features of the knee, including the tibial plateau morphology, have been shown to influence knee biomechanics and the risk of ligamentous injuries. Little is known, however, how these morphological features influence the risk of isolated meniscal injuries in the anterior cruciate ligament (ACL)-intact knee.

HYPOTHESIS

There are differences in the slopes and concavity of the tibial plateau between patients with isolated meniscal tears and matched uninjured controls.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In total, 89 patients with first-instance isolated medial (n = 37) or lateral (n = 52) meniscal injuries requiring surgical treatment (mean age, 16 ± 1 years; 35% female) were matched to 89 controls with uninjured knees and no previous injuries (mean age, 16 ± 2 years; 35% female) based on age and sex. Magnetic resonance imaging scans (preoperative for injured group) were used to measure the coronal slope of the tibial plateau, posterior slope of the medial and lateral tibial plateaus, and maximum depth of the medial tibial plateau. General linear models were used to evaluate the differences in tibial plateau morphology between the knees with and without meniscal injuries, with and without adjustment for age and sex.

RESULTS

Compared with matched controls, patients with surgically treated isolated meniscal tears had a smaller lateral tibial slope (by 2.2° [medial meniscal injury] and 1.6° [lateral meniscal injury]; P < .02), a smaller medial tibial slope (by 2.3° [medial meniscal injury] and 2.4° [lateral meniscal injury]; P < .001) and a larger medial tibial depth (by 0.8 mm [medial meniscal injury] and 0.9 mm [lateral meniscal injury]; P < .001). There were no differences in coronal tibial slope between the injured and uninjured groups. There were no differences in quantified anatomic features between the isolated medial and lateral meniscal injury groups. The same trends were observed after adjusting for age and sex.

CONCLUSION

This study suggests that patients with an isolated meniscal tear requiring surgery have a smaller posterior tibial slope and a larger medial tibial depth (more concave medial tibial plateau) than matched uninjured controls. This is contrary to what is known for ACL tears, in which a steeper posterior tibial slope and a shallower medial tibial depth have been associated with an increased risk of ACL tear.

Prevalence and a correlation analysis of discoid meniscus and femoral trochlear dysplasia

BACKGROUND

Discoid meniscus (DM) and femoral trochlear dysplasia (FTD) are common knee disorders. Both as congenital malformation, whether there is a connection between them is unclear and the research on their prevalence in the general population is inadequate. This study aimed to investigate the prevalence of FTD and DM in the general population through a large sample size, and to explore the relationship between them.

STUDY DESIGN

Retrospective study.

METHODS

Patients undergoing knee magnetic resonance imaging (MRI) examinations at our outpatient clinic were screened and 1003 patients were enrolled in DM group with 989 patients in non-DM (NDM) group. The type of DM and FTD was classified with Watanabe classification and Dejour's classification, respectively. The prevalence of FTD and DM in the general population and the relationship between them were evaluated.

RESULTS

The prevalence of DM and FTD was 10.0% and 14.5%, respectively. The overall percentage of FTD was higher in DM group (P < 0.001). The DM group has a higher percentage of all types of FTD except type D (P < 0.05), and a higher percentage of both low- and high-grade FTD (P < 0.001). There were 633 cases of type I DM and 370 cases of type II DM. The overall percentage of FTD was not significantly different between the two types (P = 0.106). No significant difference was detected for all types of FTD except type B (P < 0.05). The Type I DM group has a significant higher percentage of high-grade FTD than Type II group (P < 0.05).

CONCLUSION

Patients with a DM are more likely to have FTD regardless of the type of DM, while those with a type I DM are more prone to have a high grade FTD.

Association of AI-determined Kellgren-Lawrence grade with medial meniscus extrusion and cartilage thickness by AI-based 3D MRI analysis in early knee osteoarthritis

The associations among Kellgren-Lawrence (KL) grade, medial meniscus extrusion (MME), and cartilage thickness in knee osteoarthritis (OA) remain insufficiently understood. Our aim was to determine these associations in early to moderate medial tibiofemoral knee OA. We included 469 subjects with no lateral OA from the Kanagawa Knee Study. KL grade was assessed using artificial intelligence (AI) software. The MME was measured by MRI, and the cartilage thickness was evaluated in 18 subregions of the medial femorotibial joint by another AI system. The median MME width was 1.4 mm in KL0, 1.5 mm in KL1, 2.4 mm in KL2, and 6.0 mm in KL3. Cartilage thinning in the medial femur occurred in the anterior central subregion in KL1, expanded inwardly in KL2, and further expanded in KL3. Cartilage thinning in the medial tibia occurred in the anterior and middle external subregions in KL1, expanded into the anterior and middle central subregions in KL2, and further expanded in KL3. The absolute correlation coefficient between MME width and cartilage thickness increased as the KL grade increased in some subregions. This study provides novel insights into the early stages of knee OA and potentially has implications for the development of early intervention strategies.

The meniscal extrusion index is a reliable indirect sign of different meniscal lesion patterns: a classification based on percentage of meniscal extrusion

PURPOSE

This study's goal is to propose a straightforward classification system based on the MEI (Meniscal Extrusion Index), a measure of meniscal extrusion, that relates to various meniscal lesion patterns and has clinical and biomechanical significance. The study's secondary goal is to determine whether the standard 3 mm meniscal extrusion parameter still has value by correlating the MEI with it.

METHODS

1350 knee MRIs that were performed over the course of 2 years made up the study cohort. Following the application of inclusion and exclusion criteria, 200 of those patients were qualified to participate in the study. All the measurements examined for this study underwent an interobserver reliability test.

RESULTS

In the 1350 MRIs that were examined for this study, meniscal extrusion of any grade was present 18.9% of the time. The use of the MEI revealed three groups of patients: those with a MEI < 20%, who are likely para-physiological; those with a MEY between 20% and 40%, who are in a grey area; and those with a MEY > 40%, who have lesions that are impairing the proper meniscal function. According to the authors' findings, the percentage of meniscal extrusion did not correlate with the finite number (3 mm), making the 3 mm parameter an unreliable evaluation method.

CONCLUSIONS

This study is clinically relevant, because it proposes a simple and reproducible classification of meniscal extrusion that may aid in evaluating the severity of an extrusion and help in the diagnosis of lesions that might be difficult to identify on MRI.

LEVEL OF EVIDENCE

Level IV.

The influence of meniscal pathology in the incidence of knee osteoarthritis: a review

IMPORTANCE

Knee osteoarthritis (OA) is a common cause of pain and disability in older persons, affecting approximately 14 million individuals in the USA. Meniscal damage is also common in this age group with a prevalence of 35% in a middle-aged and older community sample and 82% in persons with evidence of radiographic knee osteoarthritis. This paper systematically reviews evidence on the association of meniscal pathology and incident radiographic knee OA.

OBSERVATIONS

We included 15 articles, published between 2013 and 2021, assessing the relationship between meniscal pathology and OA incidence (Fig. 1). The menisci are crucial load-bearing structures, and the resulting increase in biomechanical stress due to meniscal damage increases the risk for OA development. While some discrepancies are present in the literature, a clinically meaningful association has been generally established between the presence of a meniscal tear or meniscal extrusion and subsequent development of incident OA. Of note, larger radial tears as well as complex and more severe tears exhibit the strongest association with the development of incident OA. The relationship between other features of meniscal morphology-such as meniscal volume and meniscal coverage-and incident OA is less clearly documented.

CONCLUSIONS AND RELEVANCE

The early detection of meniscal pathology can be used to trigger preventative and therapeutic strategies designed to avert or delay knee OA in this at-risk population.

Evaluation of Anatomical Variations with Morphological Measurements and Their Relationship to Meniscal Injury and Ligament Damage

The purpose of this study was to reveal the anatomical risk factors for anterior and posterior cruciate ligament (ACL and PCL) injuries and menisci injury. We aim to investigate whether there are significant relationships between tibial tubercle-trochlear groove (TT-TG) distance, patella angle, trochlear sulcus angle (TSA), trochlear groove depth (TGD), medial and lateral trochlea length (MT and LT), MT/LT ratio, lateral patellar tilt angle (LPTA), patella-patellar tendon angle (P-PTA), quadriceps-patellar tendon angle (QPA), Insall-Salvati index (ISI), medial and lateral trochlear inclination (MTI and LTI) measurements and important common pathologies such as ACL, PCL, medial and lateral meniscal injuries (MM and LM), peripatellar fat pad edema, chondromalacia, and effusion. Thus, the mechanisms of injury will be better understood by revealing important anatomical variations for meniscus and ligament damage. Three hundred eighty patients with knee magnetic resonance imaging examination were included in this study. Our patients who underwent knee magnetic resonance imaging were divided into groups according to the presence of MM tear, LM tear, ACL tear, PCL tear, peripatellar fat pad edema, chondromalacia and effusion. TT-TG distance, patella angle, TSA, TGD, MT, LT, MT/LT ratio, LPTA, P-PTA, QPA, ISI, MTI, and LTI were measured. In patients with ACL tear, age, LT, ML/LT ratio, and QPA measurements were found to be significantly higher. There was no significant difference between the participants' LPTA value and the presence of ACL tear, MM and LM injury. MT and ML/LT ratio were found to be significantly lower in the group with MM tear (p <0.001). The TT-TG distance was found to be significantly lower in the group with LM tear. Increased age, LT, ML/LT ratio, and QPA are predisposed risk for ACL tear. Decreased MT and ML/LT ratio are among the risk factors for MM tear. The anatomical variations are associated with ligament and meniscal injury.

Large-Scale Analysis of Meniscus Morphology as Risk Factor for Knee Osteoarthritis

OBJECTIVE

Although it is established that structural damage of the meniscus is linked to knee osteoarthritis (OA) progression, the predisposition to future development of OA because of geometric meniscal shapes is plausible and unexplored. This study aims to identify common variations in meniscal shape and determine their relationships to tissue morphology, OA onset, and longitudinal changes in cartilage thickness.

METHODS

A total of 4,790 participants from the Osteoarthritis Initiative data set were studied. A statistical shape model was developed for the meniscus, and shape scores were evaluated between a control group and an OA incidence group. Shape features were then associated with cartilage thickness changes over 8 years to localize the relationship between meniscus shape and cartilage degeneration.

RESULTS

Seven shape features between the medial and lateral menisci were identified to be different between knees that remain normal and those that develop OA. These include length-width ratios, horn lengths, root attachment angles, and concavity. These "at-risk" shapes were linked to unique cartilage thickness changes that suggest a relationship between meniscus geometry and decreased tibial coverage and rotational imbalances. Additionally, strong associations were found between meniscal shape and demographic subpopulations, future tibial extrusion, and meniscal and ligamentous tears.

CONCLUSION

This automatic method expanded upon known meniscus characteristics that are associated with the onset of OA and discovered novel shape features that have yet to be investigated in the context of OA risk.

Meniscal degeneration is prognostic of destabilzing meniscal tear and accelerated knee osteoarthritis: Data from the Osteoarthritis Initiative

The objective of this study was to assess the prognostic potential of magnetic resonance (MR)-detected meniscal degeneration in relation to incident destabilizing meniscal tears (radial, complex, root, or macerated) or accelerated knee osteoarthritis (AKOA). We used existing MR data from a case-control study of three groups from the Osteoarthritis Initiative without radiographic KOA at baseline: AKOA, typical KOA, and no KOA. From these groups, we included people without medial and lateral meniscal tear at baseline (n = 226) and 48-month meniscal data (n = 221). Intermediate-weighted fat-suppressed MR images annually from baseline to the 48-month visit were graded using a semiquantitative meniscal tear classification criterion. Incident destabilizing meniscal tear was defined as progressing from an intact meniscus to a destabilizing tear by the 48-month visit. We used two logistic regression models to assess whether: (1) presence of medial meniscal degeneration was associated with an incident medial destabilizing meniscal tear, and (2) presence of meniscal degeneration in either meniscus was associated with incident AKOA over the next 4 years. People with the presence of a medial meniscal degeneration had three times the odds of developing an incident destabilizing medial meniscal tear within 4 years compared with a person without medial meniscus degeneration (odds ratio [OR]: 3.03; 95% confidence interval [CI]: 1.40-6.59). People with meniscal degeneration had five times the odds of developing incident AKOA within 4 years compared with a person without meniscal degeneration in either meniscus (OR: 5.04; 95% CI: 2.57-9.89). Meniscal degeneration on MR is clinically meaningful as it relates to future poor outcomes.

[Analysis of the correlation between media meniscus displacement index and medial tibiofemoral articular cartilage damage]

OBJECTIVE

To investigate the correlation between the medial meniscal indentation index (MDI) and medial tibiofemoral articular cartilage damage more than 3 degrees in patients aged 40 to 60 years old with suspected or complicated knee osteoarthritis at non-weight-bearing position, and to determine the predictive threshold.

METHODS

From June 2016 to June 2020, a total of 308 patients who underwent initial knee arthroscopic exploration for chronic knee pain were collected. The age ranged from 36 to 71 years old with an average of(56.40±1.82) years old, including 105 males and 203 females. And patients with extra-articular malformations (abnormal force lines), a history of trauma, inflammatory arthritis and other specific arthritis were excluded. Finally, 89 eligible cases were obtained, aged from 42 to 60 years old with an average of (59.50±0.71) years old, including 45 males and 44 females. The degree of cartilage damage in the medial compartment of the knee joint was recorded, which was divided into two groups(≥degree 3 and

RESULTS

A total of 89 eligible patients were obtained. Univariate analysis showed age, BMI, MDI and meniscus injury may be the independent risk factors for cartilage damage of more than 3 degrees, further binary Logistic regression analysis confirmed that MDI[OR=1.66, 95%CI(1.64, 1.69), P=0.01]and BMI [OR=1.58, 95%CI(1.17, 2.15), P=0.03] were independent risk factors for cartilage injury of more than degree 3 in enrolled patients. ROC analysis showed that MDI had more diagnostic value than BMI, and the critical value was 0.355 with a sensitivity of 89.1% and a specificity of 88.2%.

CONCLUSION

In doubt or accompanied by 40 to 60 years old patients with knee osteoarthritis, the MDI measured by non-weight-bearing knee MRI has predictive value for cartilage injury of more than degree 3 in medial tibiofemoral joint, and the critical value for diagnosis of cartilage injury of more than degree 3 is 0.355.

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Key Words

• Joint arthroscopy
• Meniscus
• Osteoarthritis

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MESH Headings

• Male
• Female
• Humans
• Adult
• Middle Aged
• Aged
• Osteoarthritis, Knee/surgery
• Cartilage, Articular/diagnostic imaging
• Cartilage, Articular/surgery
• Knee Joint/surgery
• Meniscus
• Menisci, Tibial/diagnostic imaging
• Menisci, Tibial/surgery
• Cartilage Diseases
• Magnetic Resonance Imaging/adverse effects

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Affiliation(s)

Bin Yuan Department of Orthopedics, Xinyi People's Hospital, Xuzhou 221400, Jiangsu, China
Wei Zhang Department of Orthopedics, Xinyi People's Hospital, Xuzhou 221400, Jiangsu, China

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Correlation of preoperative CT imaging shift parameters of the lateral plateau with lateral meniscal injury in Schatzker IV-C tibial plateau fractures

BACKGROUND

Schatzker IV-C is a high-energy tibial plateau fracture often accompanied by lateral meniscus injuries. While imaging examinations are routine preoperative measurements, the correlation between CT imaging shift parameters of the lateral plateau and lateral meniscal injury in Schatzker IV-C fractures remains uncovered.

METHODS

This retrospective study enrolled a total of 60 patients with Schatzker IV-C tibial plateau fractures at the First People's Hospital of Hefei. Prior to surgery, CT imaging was used to measure the numerical values of lateral plateau depression (LPD) and lateral plateau widening (LPW). The degree of lateral meniscus injury was confirmed based on intraoperative direct vision, with patients being classified into meniscus injury and non-meniscus injury groups. Dichotomous logistic regression was employed to evaluate the correlation between LPD, LPW, and lateral meniscus injury, while the optimal cut-off points for predicting lateral meniscal injury with LPD and LPW were determined using receiver operator characteristic (ROC) curves.

RESULTS

The meniscus injury group exhibited a mean LPD of 15.3 ± 3.5 mm, which was significantly higher than the non-meniscus injury group's mean LPD of 8.4 ± 3.4 mm (P < 0.05). Similarly, the meniscus injury group had a larger mean LPW of 9.4 ± 1.8 mm compared to the non-meniscus injury group's mean LPW of 6.9 ± 0.9 mm (P < 0.05). The optimal cut-off points for predicting lateral meniscal injury were determined to be 8.40 mm for LPD (with a sensitivity of 95%, specificity of 85%, and AUC of 0.898) and 7.90 mm for LPW (with a sensitivity of 75%, specificity of 90%, and AUC of 0.897).

CONCLUSIONS

Patients with Schatzker IV-C tibial plateau fractures are at a significantly higher risk of lateral meniscal injury when the LPD exceeds 8.40 mm and/or the LPW exceeds 7.90 mm. Our results may provide novel reference metrics for the early diagnosis of lateral meniscal injury in Schatzker IV-C tibial plateau fracture patients when the MRI examination is not available.

Evaluation of meniscus extrusion during stair ambulation in healthy volunteers using dynamic ultrasonography: a feasibility study

PURPOSE

This study aimed to investigate the feasibility of evaluating medial meniscus extrusion (MME) during stair ambulation.

METHODS

Twenty healthy young participants (mean age, 22.4 ± 0.9 years) were recruited for this cross-sectional study. Synchronization between the three-dimensional motion system and ultrasonography was used to quantify the extent of meniscal extrusion and knee angles during different tasks, including gait, stair ascent, and stair descent. In particular, ultrasonography was used to record the movements of both the middle and posterior segments of the meniscus to obtain detailed information about these movements in relation to the knee angle. The difference between the maximum MME and the MME at the initial contact (ΔMME) was evaluated during each task in the stance phase.

RESULTS

Visualization of the meniscus in the middle segment was limited with increasing knee flexion angle, whereas the posterior segments were visible during all tasks. ΔMME of the posterior segment during stair ascent and descent was higher than that during gait (gait: 0.68 ± 0.20 mm, ascent: 1.00 ± 0.39 mm, descent: 0.90 ± 0.27 mm, gait-ascent: p = 0.009, gait-descent: p = 0.004).

CONCLUSIONS

Evaluation that includes the posterior segment enables visualization of the medial meniscus and detection of its specific behavior during stair ambulation. These findings demonstrate the feasibility of evaluating meniscus dynamics during stair ambulation, and could contribute to a better understanding of these dynamics.

Tear patterns and locations are different between lateral and medial compartments in patients with early anatomical failure after meniscal allograft transplantation

PURPOSE

To investigate the characteristics of anatomically failed grafts within 1 year after meniscal allograft transplantation (MAT) and compare the differences between lateral and medial MATs.

METHODS

The records of consecutive patients with anatomically failed grafts within 1 year after primary MAT between 2005 and 2018 were reviewed. Anatomical failure was defined as a tear covering > 50% of the allograft or an unstable peripheral rim. The pattern and location of the graft tears were analyzed using magnetic resonance imaging or arthroscopy.

RESULTS

A total of 21 patients were included. All 21 patients had anatomical failure with tears involving > 50% of the allograft, whereas 15 had an unstable peripheral rim of the allograft. The mean failure time was 6.6 ± 3.6 months in all patients (lateral MAT, n = 15; medial MAT, n = 6). In the lateral MAT group, meniscocapsular separation was the most common pattern (n = 10, 66.7%), followed by complex (n = 3, 20.0%), radial (n = 1, 6.7%), and longitudinal (n = 1, 6.7%) tear. In the medial MAT group, a root tear was the most common pattern (n = 5, 83.3%), followed by a complex tear (n = 1, 16.7%). Meanwhile, in the lateral MAT, the midbody was the most frequently affected location (n = 9, 60.0%), followed by the posterior (n = 5, 33.3%) and anterior (n = 1, 6.7%) areas; in the medial MAT group, the posterior (n = 5, 83.3%) was the most frequently affected location, followed by the anterior area (n = 1, 16.7%). Significant differences in the pattern (P = 0.002) and location (P = 0.043) of the graft tears were found between lateral and medial MATs.

CONCLUSION

In patients with early failure after MAT, meniscocapsular separation in the midbody of the lateral compartment and root tears in the posterior area of the medial compartment were the most common. Thus, surgeons are encouraged to pay extra attention to these vulnerable areas during the early period after MAT.

LEVEL OF EVIDENCE

IV.

ACTIfit™: 38% full resorption at 8 years in a cohort of 18 cases

BACKGROUND

Preserving meniscal tissue is a major priority in young, physically active patients. Extensive meniscal defects may result in exercise pain and premature osteoarthritis. ACTIfit™ is a synthetic meniscal substitute that may improve short-term functional scores via biological integration with meniscal tissue regeneration. However, long-term data on the lifespan and chondroprotective effect of this newly formed tissue are lacking. The primary objective of this study was to assess the biological integration of ACTIfit™ based on magnetic resonance imaging (MRI) findings. The secondary objective was to evaluate long-term clinical outcomes.

HYPOTHESIS

The ACTIfit™ meniscal substitute undergoes biological integration over time, suggesting chondroprotective potential.

MATERIALS AND METHODS

A 2014 report by Baynat et al. described the 2-year clinical and radiological outcomes of 18 patients after ACTIfit™ implantation at the Clermont-Tonnerre military teaching hospital (Brest, France). The patients had chronic knee pain of at least 6 months' duration after failure of primary meniscal surgery with segmental meniscal defects. Mean age was 34.0±7.9 years. A concomitant procedure was performed in 13 (60%) patients, including osteotomy in 8 and ligament reconstruction in 5. For the current study, the clinical and radiological follow-up was at least 8 years. Assessments were with the Genovese grading scale for substitute morphology on MRI scans, International Cartilage Research Society (ICRS) score for osteoarthritis progression, and Lysholm score for clinical outcome. Failure was defined as total substitute resorption (Genovese morphology grade 1) or revision surgery with implant removal, conversion to meniscus allografting, or arthroplasty.

RESULTS

MRI scans were available for 12 (66%) patients. The reason for not having long-term MRI scans was surgery for substitute removal or arthroplasty in 3 of the remaining 6 patients. Complete implant resorption (Genovese grade 1) was noted in 7/12 (58%) patients and osteoarthritis progression to ICRS grade 3 in 4/12 (33%) patients. At last follow-up, the mean Lysholm score was significantly improved vs. baseline (79±15 vs. 55±13, P=0.005).

CONCLUSION

The frequency of complete ACTIfit™ resorption 8 years after implantation was high. This finding argues against ability of this substitute to induce the regeneration of durable meniscal tissue with a chondroprotective effect. The clinical outcome score was significantly improved at last follow-up. However, no conclusions can be drawn regarding the effectiveness of ACTIfit™ given the high frequency of concomitant surgical procedures.

LEVEL OF EVIDENCE

IV, retrospective observational cohort.

Visualization of lateral meniscus extrusion during gait using dynamic ultrasonographic evaluation

PURPOSE

Medial meniscus extrusion is one of the risk factors for knee osteoarthritis (OA). However, lateral meniscus extrusion has not been discussed, and detailed information remains unknown. In particular, the lateral meniscus has high mobility and is expected to be difficult to evaluate in terms of its behavior under static conditions. Dynamic ultrasonographic evaluation was introduced to detect the dynamic behavior of the meniscus during walking. In this study, we aimed to investigate the behavior of the lateral meniscus during walking using dynamic ultrasonographic evaluation.

METHODS

Sixteen participants with knee OA were recruited in this study. The change of lateral meniscus extrusion during walking was recorded using ultrasonography. Medial and lateral meniscal extrusion during the stance phase was measured, and meniscal mobility was defined as the difference in meniscal extrusion between minimum and maximum values (mm), medial meniscal extrusion (∆MME), and lateral meniscal extrusion (∆LME), respectively. The walking cycle and gait forms of lateral thrust were also evaluated using three-dimensional motion analysis systems and analyzed in terms of the correlation with ∆MME and ∆LME.

RESULTS

The lateral meniscus was depicted in the articular plane, and extrusion decreased during the stance phase of the gait cycle. The ∆LME was significantly higher than the ∆MME (p < 0.01). There was a significant positive correlation between ∆LME and lateral thrust (r = 0.62, p < 0.05).

CONCLUSIONS

We found that dynamic ultrasonographic evaluation can be used to visualize lateral meniscus extrusion during walking, and that its behavior is correlated to the degree of lateral thrust.

Lateral meniscus with tears or with histologic calcification does not increase the risk of lateral osteoarthritis after medial unicompartmental arthroplasty

PURPOSE

Meniscal tears or histological meniscal calcifications (in the absence of radiological chondrocalcinosis) are frequent in osteoarthritis. Whether lateral meniscal lesions influence clinical outcomes after medial unicompartmental knee arthroplasty (UKA) is unknown.

METHODS

We analyzed 130 patients (130 knees) with medial unicompartmental knee arthroplasties between 2005 and 2015. These 130 knees had full articular cartilage thickness in the lateral compartment and no radiological chondrocalcinosis on preoperative radiographs. The lateral meniscus was analyzed with preoperative MRI and a biopsy of the anterior horn at the time of surgery. Synovial fluid was collected and analyzed for calcium pyrophosphate dihydrate crystal deposition (CPPD crystals). Lateral meniscal tears were untreated when detected on MRI or during surgery, with the hypothesis that these tears on the opposite compartment would remain asymptomatic in medial UKA. At average 10-year follow-up, patients were evaluated with clinical and radiographic outcome, with a focus on the risk of joint space narrowing of the lateral femorotibial compartment.

RESULTS

CPPD crystals were present in the synovial fluid of 70 knees. Lateral meniscal tears were seen on MRI in 34 (49%) normal meniscuses of the 60 knees without CPPD crystals and in six other knees without histological meniscal calcification despite CPPD crystals. Histological calcification was present on 61 lateral meniscuses with 53 meniscal tears. The results showed no significant differences in the clinical outcomes between knees with lateral meniscal tears or lateral meniscal histological chondrocalcinosis or both lesions and those without these conditions. Additionally, radiographic progression of osteoarthritis in the opposite femorotibial compartment of the knee was not more frequent in patients with these meniscal issues. The ten year cumulative survival rates, measured by the need for total knee arthroplasty, were 91% for knees without meniscal lesions and 92% for knees with these lesions.

CONCLUSION

On this basis, treatment of meniscal tears of the lateral compartment and routine aspiration of the knee to assess for birefringent crystals in the planning of medial UKA do not appear necessary.

Subchondral insufficiency fracture is a predictive factor of osteoarthritis progression and conversion to arthroplasty in non-surgically treated medial meniscus root tear

PURPOSE

To investigate the radiographic and clinical outcomes of non-surgical treatment for medial meniscus posterior root tear (MMPRT), and prognostic factors for osteoarthritis (OA) progression and clinical failure.

METHODS

A prospectively collected database was retrospectively reviewed for patients who were diagnosed with acute medial meniscus posterior root tear (MMPRT) between 2013 and 2021 and treated non-surgically for more than 2 years. Patient demographic characteristics and clinical outcomes including pain numeric rating scale (NRS), International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and Tegner activity scale were evaluated. For radiographic evaluation, knee radiographs were obtained to assess the angle of knee alignment and Kellgren-Lawrence (K-L) grade during the first and annually follow-up visits. Baseline magnetic resonance (MR) images were reviewed for the presence of medial meniscus extrusion, bone marrow edema, subchondral insufficiency fracture of medial femoral condyle, and cartilage lesion. The OA progression group was defined as patients who experienced a worsening of one or more grades in the K-L classification system. Prognostic factors were evaluated for OA progression and conversion to total knee arthroplasty (TKA).

RESULTS

Ninety-four patients (90 female and 4 male) with a mean age of 67.0 ± 7.3 years (range, 53-83 years) were followed for a mean of 46.1 ± 22.1 months (range, 24.1-170.5). During the follow-up period, no significant differences in clinical scores were observed, and there were also no significant differences between the groups with and without OA progression. Overall, 12 patients (13%) underwent TKA at a mean of 20.7 ± 16.5 months (range, 8-69 months) and 34 patients (36%) demonstrated OA progression at a mean time of 24 ± 15 months (range, 12-62). The subchondral insufficiency fracture was a prognostic factor for OA progression (p = 0.045 for knee radiograph and p = 0.019 for MR) and conversion to TKA (RR, 4.08 [95% CI 1.23-13.57]; p = 0.022).

CONCLUSIONS

Non-surgical treatment for acute medial meniscus posterior root tear did not result in any significant change in clinical outcomes from the initial to the final follow-up. The rate of conversion to arthroplasty was 13%, and the rate of osteoarthritis progression was 36%. Furthermore, subchondral insufficiency fracture was found to be a concomitant prognostic factor correlated with OA progression and conversion to arthroplasty. This information can provide insights for physicians when discussing treatment options with patients, particularly regarding the use of non-surgical treatment and may contribute as a source for future studies of medial meniscus posterior root tear.

LEVEL OF EVIDENCE

IV.

Association of quantitative measures of medial meniscal extrusion with structural and symptomatic knee osteoarthritis progression - Data from the OAI FNIH biomarker study

OBJECTIVE

To study the association of quantitative medial meniscal position measures with radiographic and symptomatic knee osteoarthritis (OA) progression over 2-4 years.

METHODS

The FNIH OAI Biomarkers study comprised 600 participants in four subgroups: 194 case knees with combined structural (medial minimum joint space width (minJSW) loss ≥0.7 mm) and symptomatic (persistent Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale increase ≥9 [0-100 scale]) progression; 200 knees with neither structural nor symptomatic progression; 103 knees with isolated structural and 103 with isolated symptomatic progression. Coronal double echo at steady state (DESS) MRIs were used for segmenting five central slices of the medial meniscus. Associations with progression were examined using logistic regression (adjusted for demographic and clinical data).

RESULTS

Greater baseline medial meniscal extrusion was associated with combined structural/symptomatic progression (OR 1.59; 95%CI: [1.25,2.04]). No relationship was observed for tibial plateau coverage or meniscal overlap distance. The two-year increase in meniscal extrusion (OR 1.48 [1.21, 1.83]), and reduction in tibial plateau coverage (OR 0.70 [0.58,0.86]) and overlap distance (OR 0.73 [0.60,0.89]) were associated with combined progression. Greater baseline extrusion was associated with isolated structural and less extrusion with isolated symptomatic progression. The longitudinal increase in meniscal extrusion, and reduction in tibial plateau coverage and overlap distance were associated with structural, but not with symptomatic progression.

CONCLUSION

Baseline measures of medial meniscal extrusion were consistently positively associated with combined radiographic/symptomatic progression and with isolated structural, but not with isolated symptomatic progression. These measures may therefore allow one to assess the risk of structural knee OA progression and to monitor interventions restoring meniscal position and function.