Item-Specific Knee Injury and Osteoarthritis Outcome Score Characterization of Patients With Medial Meniscus Root Tear

Background

Most studies regarding medial meniscus posterior root tear (MMPRT) report total Knee injury and Osteoarthritis Outcome Score (KOOS) subscale values as important patient-reported outcomes, but there are few symptom-specific characterizations of patients with MMPRT.

Purpose/Hypothesis

The purpose of this study was to characterize the prevalence and severity of symptoms and functional limitations among patients with MMPRT based on item-level KOOS responses. It was hypothesized that patients with MMPRT would show similar symptoms to those of other meniscal tear types, with items from the KOOS pain subscale forming a majority of the most severe and prevalent symptoms.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

The records of 1466 patients with medial meniscus root tear between January 2017 and December 2021 at a single institution were reviewed. KOOS subscale scores and item-specific responses from initial evaluation were collected for each patient. Each KOOS item was scored on a scale from 1 (none/least severe) to 5 (extreme/most severe). Median and mean item-level responses were calculated and ranked in order of most to least severe. For statistical analysis, item-level prevalence rates were calculated as the proportion of patients reporting at least mild symptoms and ranked from most to least prevalent.

Results

Included were 61 patients with MMPRT verified on magnetic resonance imaging (MRI). The most severe items according to item-level KOOS response were as follows: awareness of knee problem (mean, 4.62 [95% CI, 4.47-4.78]), difficulty jumping (mean, 4.06 [95% CI, 3.73-4.39]), difficulty twisting or pivoting (mean, 4.04 [95% CI, 3.76-4.32]), difficulty kneeling (mean, 3.98 [95% CI, 3.65-4.31]), and modification of lifestyle (mean, 3.94 [95% CI, 3.69-4.20]). The most prevalent items were knee stiffness later in the day, pain going up- or downstairs, difficulty ascending stairs, difficulty getting in and out of the car, difficulty twisting or pivoting, awareness of knee problem, and modification of lifestyle, with all patients reporting at least mild symptoms for each. Of the 11 most severe and prevalent symptoms, 8 came from the KOOS-Pain item-specific responses.

Conclusion

Pain-related items made up a majority of the most severe and most prevalent symptoms as identified by the item-specific KOOS responses. However, meniscal symptoms commonly seen in other tear types, such as clicking and knee stiffness, were still quite prevalent in patients with MMPRT.

Comparison of the Predicting Performance for Fate of Medial Meniscus Posterior Root Tear Based on Treatment Strategies: A Comparison between Logistic Regression, Gradient Boosting, and CNN Algorithms

This study aimed to validate the accuracy and prediction performance of machine learning (ML), deep learning (DL), and logistic regression methods in the treatment of medial meniscus posterior root tears (MMPRT). From July 2003 to May 2018, 640 patients diagnosed with MMPRT were included. First, the affecting factors for the surgery were evaluated using statistical analysis. Second, AI technology was introduced using X-ray and MRI. Finally, the accuracy and prediction performance were compared between ML&DL and logistic regression methods. Affecting factors of the logistic regression method corresponded well with the feature importance of the six top-ranked factors in the ML&DL method. There was no significant difference when comparing the accuracy, F1-score, and error rate between ML&DL and logistic regression methods (accuracy = 0.89 and 0.91, F1 score = 0.89 and 0.90, error rate = 0.11 and 0.09; p = 0.114, 0.422, and 0.119, respectively). The area under the curve (AUC) values showed excellent test quality for both ML&DL and logistic regression methods (AUC = 0.97 and 0.94, respectively) in the evaluation of prediction performance (p = 0.289). The affecting factors of the logistic regression method and the influence of the ML&DL method were not significantly different. The accuracy and performance of the ML&DL method in predicting the fate of MMPRT were comparable to those of the logistic regression method. Therefore, this ML&DL algorithm could potentially predict the outcome of the MMRPT in various fields and situations. Furthermore, our method could be efficiently implemented in current clinical practice.

Mild to Moderate Varus Alignment in Relation to Surgical Repair of a Medial Meniscus Root Tear: A Matched-Cohort Controlled Study With 2 Years of Follow-up

BACKGROUND

Increased varus alignment of the lower extremity is known to be a poor prognostic factor for the surgical repair for a medial meniscus root tear (MMRT). However, given the concept of constitutional varus, which is present in a substantial portion of the normal population, the generally accepted surgical indication for MMRT concerning a varus alignment of 5° may be unnecessarily narrow.

PURPOSE

To compare the surgical outcomes of arthroscopic transtibial pullout repair of MMRT according to the degree of varus alignment of the lower extremity.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent isolated arthroscopic transtibial pullout repair of MMRT between January 2010 and July 2017 at one institution and had a minimum follow-up of 2 years were included in this study. Patients were classified into 1 of 2 groups: the experimental group (n = 22) included patients with a preoperative hip-knee-ankle angle between 5° and 10° varus (mild to moderate varus alignment) and the control group (n = 51) included those with a preoperative hip-knee-ankle angle <5° varus (neutral alignment). Clinical scores and radiographic parameters were compared between the groups to assess surgical outcomes, which were statistically matched for potential confounders (age, body mass index, the severity of cartilage lesion) by use of the inverse probability of treatment weighting. A noninferiority trial was performed comparing the experimental and control groups in terms of subjective outcomes (International Knee Documentation Committee subjective and Lysholm scores) and objective outcomes (postoperative medial meniscal extrusion and the rate of osteoarthritis progression).

RESULTS

There were no statistically significant differences in surgical outcomes between the groups in subjective and objective aspects, which were consistent before and after inverse probability of treatment weighting. Apart from the clinical improvement observed in both groups, overall degenerative changes in the knee were found, although progression rates did not differ between the groups. In terms of the noninferiority trial, the overall surgical outcomes in the experimental group were not inferior to those in the control group.

CONCLUSION

The short-term surgical outcomes of arthroscopic transtibial pullout repair for MMRT of patients with mild to moderate varus alignment were not inferior to but rather comparable with those with neutral alignment in terms of subjective and objective aspects. Therefore, it would be inappropriate to exclude patients with a diagnosis of MMRT from being indicated for the surgery simply because of mild to moderate varus alignment.

Effect of Posterior Horn Medial Meniscus Root Tear on In Vivo Knee Kinematics

Background:

Medial meniscus root tear (MMRT) is a recently recognized yet frequently missed meniscal tear pattern that biomechanically creates an environment approaching meniscal deficiency.

Hypothesis/Purpose:

The purpose of this study was to assess the effect of MMRT on tibiofemoral kinematics and arthrokinematics during daily activities by comparing the injured knees of subjects with isolated MMRT to their uninjured contralateral knees. The hypothesis was that the injured knee will demonstrate significantly more lateral tibial translation and adduction than the uninjured knee, and that the medial compartment will exhibit significantly different arthrokinematics than the lateral compartment in the affected limb.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Seven subjects with isolated MMRT were recruited and volumetric, density-based 3-dimensional models of their distal femurs and proximal tibia were created from computed tomography scans. High-speed, biplane radiographs were obtained of both their affected and unaffected knees. Moving 3-dimensional models of tibiofemoral kinematics were calculated using model-based tracking to assess overall kinematic variables and specific measures of tibiofemoral joint contact. The affected knees of the subjects were then compared to their unaffected contralateral knees.

Results:

Affected knees demonstrated significantly more lateral tibial translation than the uninjured contralateral limb in all dynamic activities. Additionally, the medial compartment displayed greater amounts of mobility than the lateral compartment in the injured limbs.

Conclusion:

This study suggests that MMRT causes significant changes in in vivo knee kinematics and arthrokinematics and that the magnitude of these changes is influenced by dynamic task difficulty.

Clinical Relevance:

Medial meniscus root tears lead to significant changes in joint arthrokinematics, with increased lateral tibial translation and greater medial compartment excursion. With complete root tears, essentially 100% of circumferential fibers are lost. This study will further our knowledge of meniscal deficiency and osteoarthritis and provide a baseline for more common forms of medial meniscal injuries (vertical, horizontal, radial), with various degrees of circumferential fiber function remaining.