Impact of type of meniscal tear on radiographic and symptomatic knee osteoarthritis: a sixteen-year followup of meniscectomy with matched controls

Association between thigh muscle strength four years after partial meniscectomy and radiographic features of osteoarthritis 11 years later

Background

Meniscus injury and meniscectomy both entail increased risk of knee osteoarthritis (OA). Thigh muscle weakness is a suggested mediator of OA but there is little evidence of its importance for knee OA development after meniscectomy. This study aimed to examine the association between thigh muscle strength after partial meniscectomy in middle-aged subjects with a non-traumatic meniscal tear and later radiographic knee OA changes.

Methods

Thirty-four out of 45 participants in an exercise-trial underwent testing for isokinetic thigh muscle strength 4 years after arthroscopic partial meniscectomy and had radiographic examination 11 years later (15 years post-surgery, mean age at follow-up of 57 years (range 50–61)). Outcomes were grade of joint space narrowing and osteophyte score in the medial tibiofemoral compartment of the operated knee and the contralateral knee. We tested the association between muscle strength at baseline and the radiographic outcomes at follow-up using logistic regression analyses adjusted for sex and overweight.

Results

At follow-up, 33/34 subjects had joint space narrowing and 27/34 subjects had osteophytes in the operated knee, in the contralateral knee joint space narrowing was found in 23 subjects. In the operated knee baseline knee extensor and flexor strength were negatively associated with grade of joint space narrowing at follow-up (OR 0.972 and 0.956, p = 0.028 and 0.026, respectively) and also with osteophyte score (OR 0.968 and 0.931, p = 0.017 and 0.011, respectively). In the contralateral knee longitudinal associations between strength and radiographic OA features were similar, OR 0.949–0.972, p < 0.05.

Conclusion

The finding that stronger thigh muscles 4 years after meniscectomy were associated with less severe osteoarthritic changes in the medial tibiofemoral compartment of both the operated and contralateral knee 11 years later, may suggest that strong thigh muscles can help to preserve joint integrity in middle-aged subjects at risk of knee OA.

Osteoarthritis development related to cartilage quality-the prognostic value of dGEMRIC after anterior cruciate ligament injury

OBJECTIVE

Rupture of the anterior cruciate ligament (ACL) increases the risk of developing osteoarthritis (OA). Delayed Gadolinium enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) investigates cartilage integrity through T1-analysis after intravenous contrast injection. A high dGEMRIC index represents good cartilage quality. The main purpose of this prospective cohort study was to investigate the prognostic value of the dGEMRIC index regarding future knee OA.

METHOD

31 patients with ACL injury (mean age 27 ± 6.7 (±SD) years, 19 males) were examined after 2 years with 1.5T dGEMRIC of femoral cartilage. Re-examination 14 years post-injury included weight-bearing knee radiographs, Lysholm and Knee Osteoarthritis Outcome Score (KOOS).

RESULTS

At the 14-year follow up radiographic OA (ROA) was present in 68% and OA symptoms (SOA) in 42% of the injured knees. The dGEMRIC index of the medial compartment was lower in knees that developed medial ROA, 325 ± 68 (ms±SD) vs 376 ± 47 (51 (7-94)) (difference of means (95% confidence interval (CI))), in patients that developed symptomatic OA (SOA), 327 ± 61 vs 399 ± 42 (52 (11-93)), and poor knee function 337 ± 54 vs 381 ± 52 (48 (7-89)) compared to those that did not develop ROA, SOA or poor function. The dGEMRIC index correlated negatively with the OARSI osteophyte score in medial (r = -0.44, P = 0.01) and lateral (r = -0.38, P = 0.03) compartments.

CONCLUSION

The associations between a low dGEMRIC index and future ROA, as well as SOA, are in agreement with previous studies and indicate that dGEMRIC has a prognostic value for future knee OA.

Quantifying the likelihood and costs of hip replacement surgery after sports injury: A population-level analysis

OBJECTIVES

To quantify the likelihood of hip replacement (HR) surgery at a population level up to 15 years after sports injury.

DESIGN

Cohort study.

SETTINGS

Public and private hospitals in the state of Victoria, Australia.

PARTICIPANTS

The cohort was established by linking administrative datasets capturing all hospital admissions and emergency department (ED) presentations. All sports injury presentations from 2000 to 2005 and HR admissions from 2000 to 2015 were identified using ICD-10-AM codes.

MAIN OUTCOME MEASURES

Time to HR (number of days from sports injury admission to HR admission).

RESULTS

Over the study period there were 64,750 sports injuries (including 815 hip or thigh musculoskeletal injuries) that resulted in ED presentation or hospitalisation, and 368 HR procedures. Compared to all other sports injuries, having a hip or thigh injury tripled the hazard of subsequent HR in multivariate analysis (hazard ratio 3.07, 95%CI 2.00-4.72). Of the main hip or thigh injury types, femoral fractures (hazard ratio 3.08, 95%CI 1.77-5.36) and hip dislocations (hazard ratio 5.64, 95%CI 2.34-13.58) were significantly associated with HR.

CONCLUSION

Sports-related hip or thigh musculoskeletal injury is associated with a significantly higher likelihood of HR within 15 years. Effective injury prevention and appropriate post-injury management are needed to curtail this population burden.

Relative difference among 27 functional measures in patients with knee osteoarthritis: an exploratory cross-sectional case-control study

Background

To raise the effectiveness of interventions, clinicians should evaluate important biopsychosocial aspects of the patient’s situation. There is limited knowledge of which factors according to the International Classification of Function, Disability, and Health (ICF) are most deviant between patients with knee osteoarthritis (KOA) and healthy individuals. To assist in measures’ selection, we aimed to quantify the differences between patients with KOA and healthy controls on various measures across the ICF dimensions of body function, activity, and participation.

Methods

We performed an exploratory cross-sectional case-control study. In total, 28 patients with mild-to-moderate KOA (mean age 61 years, 64% women) referred by general physicians to a hospital’s osteoarthritis-school, and 31 healthy participants (mean age 55 years, 52% women), volunteered. We compared between-group differences on 27 physical and self-reported measures derived from treatment guidelines, trial recommendations, and trial/outcome reviews. Independent t-test, Chi-square, and Mann-Whitney U test evaluated the significance for continuous parametric, dichotomous, and ordinal data, respectively. For parametric data, effect sizes were calculated as Cohen’s d. For non-parametric data, ds were estimated by p-values and sample sizes according to statistical formulas. Finally, all ds were ranked and interpreted after Hopkins’ scale. An age-adjusted sensitivity-analysis on parametric data validated those conclusions.

Results

Very large differences between patients and controls were found on the Pain numeric rating scale¹, the Knee Injury and Osteoarthritis Scale (KOOS, all subscales)², as well as the Örebro Musculoskeletal psychosocial scale³ (P < 0.0001). Large differences were found on the Timed 10-steps-up-and-down stair climb test⁴ and Accelerometer registered vigorous-intensity physical activity in daily life⁵ (P < 0.001). Respectively, these measures clustered on ICF as follows: ¹body function, ²all three ICF-dimensions, ³body function and participation, ⁴activity, and ⁵participation.

Limitations

The limited sample excluded elderly patients with severe obesity.

Conclusions

Very large differences across all ICF dimensions were indicated for the KOOS and Örebro questionnaires together for patients aged 45–70 with KOA. Clinicians are suggested to use them as means of selecting supplementary measures with appropriate discriminative characteristics and clear links to effective therapy. Confirmative studies are needed to further validate these explorative and partly age-unadjusted conclusions.

A three-dimensional printed silk-based biomimetic tri-layered meniscus for potential patient-specific implantation

Employing tissue engineering principles aided by three-dimensional (3D) printing strategies to fabricate meniscus tissue constructs could help patients with meniscus injury regain mobility, improve pain management and reduce the risk of development of knee osteoarthritis. Here we report a 3D printed meniscus scaffold that biomimics the internal and bulk architecture of the menisci. A shear-thinning novel silk fibroin-gelatin-based bioink with high print fidelity was optimized for the fabrication of scaffolds to serve as potential meniscus implants. Physicochemical characterization of the fabricated scaffolds shows optimum swelling, degradation and mechanical properties. Further, the scaffolds were seeded with meniscus fibrochondrocytes to validate their bioactivity. Fibrochondrocytes seeded on the scaffolds maintained their phenotype and proliferation, and enhanced glycosaminoglycan and total collagen synthesis was observed. Gene expression profile, biochemical quantification and histological studies confirmed the ability of the scaffolds to form meniscus-like tissue constructs. The scaffolds were found to possess amenable immunocompatibility in vitro as well as in vivo. Due to their excellent biological and physicochemical characteristics, these 3D printed scaffolds may be fine-tuned into viable alternatives to the present clinical treatment approaches to meniscus repair.

Evidence that Swimming May Be Protective of Knee Osteoarthritis: Data from the Osteoarthritis Initiative

BACKGROUND

To date, there have not been any epidemiologic studies that have evaluated the association between swimming over a lifetime and knee health.

OBJECTIVE

The study aimed to evaluate the relationship of a history of swimming with knee pain, radiographic knee OA (ROA), and symptomatic knee OA (SOA).

DESIGN

Cross-sectional retrospective study.

SETTING

Four academic centers in the United States.

PARTICIPANTS

Respondents to the historical physical activity survey within the Osteoarthritis Initiative with knee radiographs and symptom assessments.

METHODS

In this retrospective study nested within the Osteoarthritis Initiative, researchers performed logistic regression with the predictor being swimming over a lifetime and over particular age ranges.

MAIN OUTCOME MEASUREMENTS

Person-based definitions of frequent knee pain, ROA, and SOA.

RESULTS

A total of 2637 participants were included, with a mean age of 64.3 years (SD 8.9), body mass index of 28.4 kg/m² (SD 4.9), and 44.2% male. Over a lifetime, the adjusted prevalence measures for frequent knee pain, ROA, and SOA for any versus no history of swimming were 36.4% (33.4% - 39.5%) v. 39.9% (37.4% - 42.5%), 54.3% (51.0% - 57.6%) v. 61.1% (58.4% - 63.7%), and 21.9% (19.4% - 24.7%) v. 27.0% (24.7% - 29.4%) respectively.

CONCLUSIONS

This is the first epidemiologic study to indicate that swimming is potentially beneficial toward knee health, particularly when performed earlier in life (before age 35). Future prospective studies are needed to confirm these findings and to better scrutinize the associations in older age groups.

Discoid lateral meniscus: a simple horizontal tear was associated with less articular cartilage degeneration compared to other types of tear

PURPOSE

The relationship between the tear type of discoid lateral meniscus (DLM) and articular cartilage degeneration has not been well studied.

METHODS

Data from patients with DLM tears who underwent arthroscopic surgery, between 2008 and 2016, were reviewed retrospectively. Demographic variables were obtained from medical records. The types of DLM and meniscal tear and status of cartilage were assessed using operation records and arthroscopic images. Patients were assigned to horizontal or non-horizontal tear groups according to the types of the tear. Factors affecting cartilage degeneration of the lateral femoral condyle (LFC) and lateral tibial plateau (LTP) were identified using logistic regression analysis. The horizontal tear group was divided into two subgroups on the basis of the median value of duration of symptoms and difference in cartilage degeneration between the two subgroups was evaluated.

RESULTS

Overall, 355 knees were enrolled and assigned to the horizontal (n = 53) or the non-horizontal (n = 302) tear groups. The incidence of International Cartilage Repair Society grades 2-4 cartilage lesions of the LFC (0%, P < 0.001) and LTP (24.5%, P < 0.001) was significantly lower in the horizontal tear group than in the non-horizontal tear group. Horizontal tear [LFC, odds ratio (OR) = 0.02, P < 0.001; LTP, OR = 0.27, P < 0.001] and age (LFC, OR = 1.04, P < 0.001; LTP, OR = 1.03, P < 0.001) were significantly related to cartilage status. There was no difference in cartilage degeneration between the two subgroups in the horizontal tear group.

CONCLUSIONS

A simple horizontal tear was associated with less articular cartilage degeneration compared to other types of tear in the DLM. In the case of simple horizontal tear, there was no difference in the degree of cartilage degeneration according to the duration of symptoms. Therefore, it is not necessary to perform surgical treatment promptly in cases of simple horizontal tears unless the patient's symptoms are severe.

LEVEL OF EVIDENCE

III, Case-Control Study.

Extracorporeal Shockwave Therapy Accelerates the Healing of a Meniscal Tear in the Avascular Region in a Rat Model

BACKGROUND

The treatment of meniscal tears in the avascular region remains a clinical challenge. Extracorporeal shockwave therapy (ESWT) is a minimally invasive, safe, and effective therapy for various orthopaedic disorders. However, the therapeutic effect of ESWT on meniscal tears has not been reported.

PURPOSE

To evaluate the therapeutic effect of ESWT in the treatment of meniscal tears.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve-week-old male Wistar rats were divided into 3 groups (normal, ESWT-, and ESWT+). The authors made a full-thickness 2-mm longitudinal tear in the avascular region of the anterior horn in the latter 2 groups. At 1 week after surgery, the ESWT+ group received 800 impulses of shockwave at 0.22-mJ/mm² energy flux density in a single session. The authors performed a histological examination to evaluate meniscal healing (n = 10 for each group) and immunohistochemistry to analyze the expression of bromodeoxyuridine (BrdU; n = 5 for each group) and CCN family member 2/connective tissue growth factor (CCN2/CTGF; n = 5 for each group) at 2, 4, and 8 weeks after ESWT. The mRNA levels of CCN2, SOX 9, VEGF-a, aggrecan, Col1a2, and Col2a1 at the site of the meniscal tear at 4 weeks after ESWT were quantitatively evaluated by a real-time polymerase chain reaction (n = 5 for each group).

RESULTS

The meniscus healing scores in the ESWT+ group were significantly higher than those in the ESWT- group at 4 weeks and 8 weeks. The ratio of BrdU-positive cells was the highest in the ESWT+ group at all observation periods. The ratio of CCN2-positive cells was highest in the ESWT+ group at 4 and 8 weeks. In the ESWT+ group, real-time polymerase chain reaction revealed that the levels of CCN2, SOX9, aggrecan, and Col2a1 were upregulated (All significant data were P < .05).

CONCLUSION

ESWT promoted the healing of meniscal tears in the avascular area. ESWT stimulated proliferation of meniscal cells and the upregulation of cartilage-repairing factors such as CCN2, with the upregulation of cartilage-specific extracellular matrix expression.

CLINICAL RELEVANCE

ESWT may be an effective therapeutic option that promotes meniscal healing in the avascular region.

Trends in Concomitant Meniscal Surgery Among Pediatric Patients Undergoing ACL Reconstruction: An Analysis of ABOS Part II Candidates From 2000 to 2016

Background

Rates of anterior cruciate ligament (ACL) reconstruction among pediatric and adolescent patients are increasing. Limited knowledge exists about population-level rates of concomitant meniscal surgery in this age group.

Purpose/Hypothesis

This study sought to examine trends in concomitant meniscal procedures and describe short-term complications in pediatric and adolescent patients undergoing ACL reconstruction. We hypothesized that overall meniscal surgery rates are increasing and that the likelihood of performing meniscal repair or meniscectomy is associated with patient- and surgeon-specific factors.

Study Design

Cross-sectional study.

Methods

We queried ACL procedures in patients younger than 19 years reported by American Board of Orthopaedic Surgery (ABOS) part II examination candidates from 2000 to 2016. Regression models examined associations between patient and surgeon characteristics, year of surgery, follow-up time, meniscal procedure type, and number and type of complications.

Results

A total of 9766 cases were identified. Females represented 46% (n = 4468) of included cases. Mean patient age was 16.1 years (SD, 1.62 years; range, 0-18 years). The rate of concomitant ACL-meniscal procedures increased from the years 2000 to 2016 (49%-60%; P = .005). Surgeons with sports medicine (+7.0%) or pediatric orthopaedic fellowship (+6.6%) training had a higher likelihood of reporting a concomitant ACL-meniscal procedure (P = .003 and .006, respectively). Sports medicine-trained surgeons were more likely to perform meniscal repair compared with meniscectomy (+3.0%; P = .016). Younger patient age was associated with increased likelihood of undergoing meniscal repair compared with meniscectomy. Overall reported complication rate was 12.8%. Notable reported complications included infection (1.61%), arthrofibrosis (1.14%), and deep venous thrombosis or pulmonary embolism (0.11%). Sports medicine and pediatric orthopaedic fellowship training was associated with higher rates of reporting postoperative stiffness and/or arthrofibrosis.

Conclusion

Among ABOS part II candidates, concomitant ACL-meniscal surgery has become more common than isolated ACL procedures. Procedures involving sports medicine fellowship-trained surgeons and younger patients were associated with increased rates of meniscal repair compared with meniscectomy. Pediatric orthopaedic and sports medicine training was associated with a greater likelihood of being involved in a concomitant ACL-meniscal procedure of any kind, and surgeons with such training also reported a higher incidence of postoperative stiffness and/or arthrofibrosis in patients.

Ultrasound Assessment of Weight-Bearing and Non-Weight-Bearing Meniscal Extrusion: A Reliability Study

BACKGROUND

Ultrasound has become a useful instrument in evaluating musculoskeletal pathology. Recent studies suggest that ultrasound imaging of weight-bearing menisci may enhance the assessment of knee pathology, such as osteoarthritis (OA) and meniscal injuries.

OBJECTIVE

The primary aim of this study was to determine the intrarater and interrater reliability of ultrasound measurements of medial meniscal extrusion (MME) after a brief training session.

DESIGN

Prospective reliability study.

SETTING

Physical medicine and rehabilitation (PM&R) department within a tertiary care institution.

PARTICIPANTS

Forty-five participants (29 female, 16 male) were recruited to serve as models, 24 of whom had healthy knees and 21 of whom had radiographically confirmed medial compartment knee OA. Three physician sonographers (1 = experienced, 1 = sports medicine fellow, 1 = post-graduate year [PGY]-4 PM&R resident) were recruited to serve as operators.

METHODS OR INTERVENTIONS

Operators received a brief training session on identifying and measuring MME. All operators measured bilateral MME in each model in the standing and supine positions on two separate days. Operators were blinded to all measurements.

MAIN OUTCOME MEASUREMENTS

Primary outcomes were inter- and intrarater intraclass correlation coefficients (ICCs) of MME measurements among operators with different levels of ultrasound experience.

RESULTS

Supine MME intrarater reliability ICCs were 0.927, 0.885, and 0.780 for the experienced physician, sports medicine fellow, and PGY-4 operators, respectively. Standing MME intrarater reliability ICCs were 0.941, 0.902, and 0.824 for the experienced physician, sports medicine fellow, and PGY-4 operators, respectively. Interrater reliability ICCs were 0.896 and 0.842 for supine and standing measurements, respectively. There was a statistically significant increase in intrarater reliability with experience between the PGY-4 resident and experienced physician operators.

CONCLUSIONS

Operators with different levels of ultrasound experience demonstrated good MME measurement intra- and interrater reliabilities in both supine and standing positions.

The 6-m timed hop test is a prognostic factor for outcomes in patients with meniscal tears treated with exercise therapy or arthroscopic partial meniscectomy: a secondary, exploratory analysis of the Odense-Oslo meniscectomy versus exercise (OMEX) trial

PURPOSE

To identify the prognostic factors for 2-year patient-reported outcomes in middle-aged patients with degenerative meniscal tears treated with exercise therapy (ET) or arthroscopic partial meniscectomy (APM).

METHODS

One hundred and seven patients, with mean age 49.6 (SD 6.2) years and BMI 25.7 (SD 3.7), were included in this analysis of data from the OMEX trial ( http://www.clinicaltrials.gov NCT01002794). Linear and Poisson regression models were built to explore the associations between potential prognostic factors (patient characteristics, knee function-related and disease-related factors) and 2-year patient-reported outcomes: the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales Pain, Symptoms, ADL, Sport/Rec, QoL and 5-point Global Rating of Change scales for knee pain (GRC Pain) and function (GRC Function). Analyses were performed for the whole cohort and for the two treatment groups (n = 55 and 52) with adjustments for age, sex, BMI and baseline KOOS.

RESULTS

For the whole cohort, a 1-s better baseline 6-m timed hop test result was associated with 3.1-7.1 points better 2-year scores for all KOOS subscales (95% CIs 1.1-5.2 to 4.1-10.1 points). A 1.61-2.80 s better test was associated with scores equivalent to previously calculated clinical relevant differences for each KOOS subscale. For the groups of patients treated with ET and APM, respectively, 2.09-3.60 s and 0.63-1.99 s better tests were associated with clinical relevant differences. For the whole cohort, a 1-s better test was associated with 26% (95% CI 15-38%) and 22% (95% CI 11-34%) higher possibility for better or much better GRC Pain and Function scores. Patients treated with ET had 17% (95% CI 2-33%) increased possibility for better or much better GRC Pain score, and patients treated with APM had 65% (95% CI 32-108%) and 70% (95% CI 38-109%) increased possibility for better or much better GRC Pain and Function scores.

CONCLUSIONS

The 6-m timed hop test result was a significant prognostic factor for 2-year patient-reported outcomes in middle-aged patients with degenerative meniscal tears, especially in those treated with APM.

LEVEL OF EVIDENCE

II.

Torn discoid lateral meniscus is associated with increased medial meniscal extrusion and worse articular cartilage status in older patients

PURPOSE

To compare the clinical, imaging, and arthroscopic characteristics of the torn discoid lateral meniscus (TDLM) in patients greater than 40 years of age with matched controls.

METHODS

One hundred and ninety-four older patients (211 knees) who underwent arthroscopic surgery for a TDLM were consecutively recruited (Group 1). Another 211 age- and sex-matched controls with a torn semilunar lateral meniscus were included in this study (Group 2). Statistical analyses were used to determine the differences in the clinical, imaging, and arthroscopic characteristics between the two groups.

RESULTS

In our series, more severe medial meniscal extrusion on magnetic resonance imaging was present in Group 1 than in Group 2 and more serious osteoarthritic changes were observed in both the medial and lateral compartments in Group 1. Under the same conditions, chondral lesions in the knee were more serious in Group 1 than in Group 2 when patients were subgrouped according to the presence of a horizontal tear or complex tear.

CONCLUSIONS

In the present study, older patients with a torn discoid lateral meniscus exhibited greater and more severe medial meniscal extrusion and more serious osteoarthritis. Therefore, knees with a discoid lateral meniscus displaying medial meniscal extrusion should be monitored carefully with long-term follow-up, because a medial meniscal extrusion may increase the risk of progression to degenerative osteoarthritis of the medial compartment. Regarding the clinical relevance, these findings will be helpful in further revealing that a torn discoid lateral meniscus may affect not only the cartilage in the lateral compartment but also the cartilage in the medial compartment and medial meniscal extrusion.

LEVEL OF EVIDENCE

III.

Predictors of Patient-Reported Outcomes at 2 Years After Revision Anterior Cruciate Ligament Reconstruction

BACKGROUND

Patient-reported outcomes (PROs) are a valid measure of results after revision anterior cruciate ligament (ACL) reconstruction. Revision ACL reconstruction has been documented to have worse outcomes when compared with primary ACL reconstruction. Understanding positive and negative predictors of PROs will allow surgeons to modify and potentially improve outcome for patients.

PURPOSE/HYPOTHESIS

The purpose was to describe PROs after revision ACL reconstruction and test the hypothesis that patient- and technique-specific variables are associated with these outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Patients undergoing revision ACL reconstruction were identified and prospectively enrolled by 83 surgeons over 52 sites. Data included baseline demographics, surgical technique and pathology, and a series of validated PRO instruments: International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index, and Marx Activity Rating Scale. Patients were followed up at 2 years and asked to complete the identical set of outcome instruments. Multivariate regression models were used to control for a variety of demographic and surgical factors to determine the positive and negative predictors of PRO scores at 2 years after revision surgery.

RESULTS

A total of 1205 patients met the inclusion criteria and were successfully enrolled: 697 (58%) were male, with a median cohort age of 26 years. The median time since their most recent previous ACL reconstruction was 3.4 years. Two-year questionnaire follow-up was obtained from 989 patients (82%). The most significant positive predictors of 2-year IKDC scores were a high baseline IKDC score, high baseline Marx activity level, male sex, and having a longer time since the most recent previous ACL reconstruction, while negative predictors included having a lateral meniscectomy before the revision ACL reconstruction or having grade 3/4 chondrosis in either the trochlear groove or the medial tibial plateau at the time of the revision surgery. For KOOS, having a high baseline score and having a longer time between the most recent previous ACL reconstruction and revision surgery were significant positive predictors for having a better (ie, higher) 2-year KOOS, while having a lateral meniscectomy before the revision ACL reconstruction was a consistent predictor for having a significantly worse (ie, lower) 2-year KOOS. Statistically significant positive predictors for 2-year Marx activity levels included higher baseline Marx activity levels, younger age, male sex, and being a nonsmoker. Negative 2-year activity level predictors included having an allograft or a biologic enhancement at the time of revision surgery.

CONCLUSION

PROs after revision ACL reconstruction are associated with a variety of patient- and surgeon-related variables. Understanding positive and negative predictors of PROs will allow surgeons to guide patient expectations as well as potentially improve outcomes.

Acoustic Emissions as a Non-invasive Biomarker of the Structural Health of the Knee

The longitudinal assessment of joint health is a long-standing issue in the management of musculoskeletal injuries. The acoustic emissions (AEs) produced by joint articulation could serve as a biomarker for joint health assessment, but their use has been limited by a lack of mechanistic understanding of their creation. In this paper, we investigate that mechanism using an injury model in human lower-limb cadavers, and relate AEs to joint kinematics. Using our custom joint sound recording system, we recorded the AEs from nine cadaver legs in four stages: at baseline, after a sham surgery, after a meniscus tear, and post-meniscectomy. We compare the resulting AEs using their b-values. We then compare joint anatomy/kinematics to the AEs using the X-ray reconstruction of moving morphology (XROMM) technique. After the meniscus tear the number and amplitude of the AE peaks greatly increased from baseline and sham (b-value = 1.33 ± 0.15; p < 0.05). The XROMM analysis showed a close correlation between the minimal inter-joint distances (0.251 ± 0.082 cm during extension, 0.265 ± .003 during flexion, at 145°) and a large increase in the AEs. This work provides key insight into the nature of joint AEs, and details a novel technique and analysis for recording and interpreting these biosignals.

The biomechanical changes of load distribution with longitudinal tears of meniscal horns on knee joint: a finite element analysis

Background

Meniscal horns are important structures of meniscus, and longitudinal tears of these places could significantly change the load distribution among the knee joint. Few studies concerned the stress concentrated on bones, which may induce the osteonecrosis of subchondral bone. The goal of this study was to construct a finite element (FE) model with high fidelity of the knee joint and evaluate the biomechanical changes of load distribution of components after longitudinal tears of the horns of meniscus.

Methods

Computed tomography and magnetic resonance images were used to develop the FE model, and two different kinds of simulations, the vertical and the anterior load, mimicking the static stance and slight flexion simulations, were applied after longitudinal tears of the horns of meniscus.

Results

Significantly elevated peak compressive and shear stress was observed on the menisci, cartilages, and subchondral bones, and enlarged meniscus extrusion was noticed. Between all the four types of longitudinal tears investigated in this study, longitudinal tears at the posterior horn of the medial meniscus were found to be the most significant.

Conclusions

These findings showed that longitudinal tears of the meniscal horns lead to increased magnitude and changed distribution of stress and indicated the important role of posterior horn of medial meniscus. This may contribute to the mechanism between meniscal tears and spontaneous subchondral bone osteonecrosis.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1255-1) contains supplementary material, which is available to authorized users.

Evaluation of Meniscal Regeneration in a Mini Pig Model Treated With a Novel Polyglycolic Acid Meniscal Scaffold

BACKGROUND

Meniscal injury is a severe impediment to movement and results in accelerated deterioration of the knee joint.

PURPOSE

To evaluate the effect of a novel meniscal scaffold prepared from polyglycolic acid coated with polylactic acid/caprolactone on the treatment of meniscal injury in a mini pig model.

STUDY DESIGN

Controlled laboratory study.

METHODS

The model was established with a 10-mm resection at the anterior medial meniscus on both knee joints. A scaffold was implanted in the right knee joint. The meniscal scaffold was inserted and sutured next to the native meniscus. The histological analysis was performed to determine meniscal regeneration with safranin O staining, cell proliferation with PCNA, inflammation with TNF, and collagen structure and production with picrosirius red and immunofluorescence. Cartilage degeneration was evaluated with Safranin O. Meniscal regeneration and joint fluid were evaluated with magnetic resonance imaging.

RESULTS

Although compressive stress and elastic modulus were significantly lower in the scaffold than in the native porcine menisci, ultimate tensile stress was similar. Implanted scaffolds were covered with tissue beginning at 4 weeks, with increased migration of proliferating cells to the implant area at 4 and 8 weeks. Scaffolds were absorbed with freshly produced collagen at 24 weeks. Cartilage degeneration was significantly lower in the meniscus-implanted group than in the meniscectomy group. Magnetic resonance imaging results did not show severe accumulation of joint fluids, suggesting negligible inflammation. Density of the implanted menisci was comparable with that of the native menisci.

CONCLUSION

Meniscal scaffold prepared from polyglycolic acid has therapeutic potential for meniscal regeneration.

CLINICAL RELEVANCE

This meniscal scaffold can improve biological knee reconstruction and prevent the increase of total knee arthroplasty.

Influence of an unloader brace on lower limb electromyographic activity in individuals with predominant lateral osteoarthritis after anterior cruciate ligament reconstruction

OBJECTIVE

To determine the immediate effects of a varus unloader knee brace on lower-limb electromyographic activity in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction.

METHODS

Electromyographic data were recorded in 19 individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction during walking under three conditions: (i) no brace, (ii) unadjusted brace (no varus adjustment), and adjusted brace (varus adjustment). Variables of interest were statistically analyzed using repeated measures analysis of variance.

RESULTS

There were no significant differences in muscle co-contraction between the three test conditions. The adjusted brace resulted in delayed offset of gluteus maximus (mean difference [95% CI]: 72ms [24, 119]), and earlier onset of gluteus medius (59ms [21, 97]) compared to no brace. The adjusted brace delayed onset of lateral gastrocnemius compared to no brace (53ms [28, 78]) and the unadjusted brace (39ms [7, 71]) and reduced average activation amplitude of gluteus maximus (-4mV [-6, -1]) and lateral gastrocnemius (-9mV [-16, -2]) compared to no brace.

CONCLUSIONS

The unloader brace did not produce significant changes in muscle co-contraction in individuals with lateral knee osteoarthritis and valgus malalignment after anterior cruciate ligament reconstruction. Significant changes in gluteal and gastrocnemius muscle activation timing and amplitude were observed, however, it is not clear whether these changes are of clinical importance.

Knee-related quality of life, functional results and osteoarthritis at a minimum of 20 years' follow-up after anterior cruciate ligament reconstruction

BACKGROUND

Few studies in the literature show results with more than 20 years of follow-up after anterior cruciate ligament reconstruction (ACLR). The main purpose of this retrospective study was to describe knee-specific quality of life, functional results and prevalence of osteoarthritis (OA) of the knee in patients with ACLR using bone-patellar tendon-bone (BPTB) autograft with ultra-long-term follow-up.

METHODS

Prospective analyzed data included demographics, meniscus status, radiographic OA, KT-1000 arthrometer measurements and physical examinations. KOOS, Lysholm and IKDC subjective surveys were conducted. Multivariate and univariate logistic models were used to determine the effect of potential predictors of OA and symptomatic knees.

RESULTS

Seventy-two knees were included at a median follow-up of 22 (IQR 21-25) years postoperatively. Radiographic scores were normal in 15%, nearly normal in 57%, abnormal in 18% and severely abnormal in 10%. Multivariate analysis showed that the predictive factor for the presence of OA in the long-term was an associated meniscal lesion; patients with meniscal lesions were 3.9 times as likely to develop OA in comparison with those without meniscal injury. The subjective scores were progressively and significantly lower as the level of OA was greater.

CONCLUSION

At a median of 22 years of follow-up, this study shows that patellar tendon autograft ACL reconstruction provides good clinical outcomes, with clinically objective knee stability and a 28% prevalence of OA. Additionally, we identified that meniscal injury at time of surgery was an independent predictor of OA.

LEVEL OF EVIDENCE

Level IV; case series.

Changes in total lower limb support moment in middle-aged patients undergoing arthroscopic partial meniscectomy - A longitudinal observational cohort study

BACKGROUND

Patients with a meniscal tear are frequently treated with arthroscopic partial meniscectomy (APM) which may alter the net extension moment across the entire lower limb - known as the total support moment (TSM).

PURPOSE

To investigate changes in TSM during walking in patients undergoing APM.

METHODS

Three-dimensional motion analysis of walking was performed in individuals with meniscal tear prior to APM and 12 months after. Peak TSM, positive ankle (ASM), knee (KSM), and hip (HSM) moments at the time of peak TSM were calculated together with corresponding angular impulses.

RESULTS

Patients (n = 20) were middle aged (45.9 ± 6.3 years) and the majority male (70%). At baseline a lower KSM (mean [95%CI]; 0.59 Nm/BM · HT% [-1.93; 3.11], P = 0.048) and a trend towards lower peak TSM (0.46 Nm/BM · HT% [-1.82; 2.78], P = 0.099) were observed for the APM leg compared with the contralateral. Pre- versus post-APM change scores indicated a relative decrease in loading of the contralateral leg for peak TSM (-0.49 Nm/BM · HT% [-0.96; -0.01], P = 0.047) and a trend towards a relative increase in loading of the APM leg for peak KSM (-0.41 Nm/BM · HT% [-0.92; 0.09], P = 0.105). No differences were observed in angular impulse variables.

CONCLUSIONS

Prior to APM a strategy to unload the injured knee was manifested by reduced KSM and a tendency to a reduced peak TSM. A more equal distribution of joint moments between injured and contralateral legs was observed 12 months following APM.

Walking Ground Reaction Force Post-ACL Reconstruction: Analysis of Time and Symptoms

PURPOSE

The association between lower-extremity loading and clinically relevant knee symptoms at different time points after anterior cruciate ligament reconstruction (ACLR) is unclear. Vertical ground reaction force (vGRF) from walking was compared between individuals with and without clinically relevant knee symptoms in three cohorts: <12 months post-ACLR, 12-24 months post-ACLR, and >24 months post-ACLR.

METHODS

One hundred twenty-eight individuals with unilateral ACLR were classified as symptomatic or asymptomatic, based on previously defined cutoff values for the Knee Osteoarthritis and Injury Outcome Score (<12 months post-ACLR [symptomatic n = 28, asymptomatic n = 24]; 12-24 months post-ACLR [symptomatic n = 15, asymptomatic n = 15], and >24 months post-ACLR [symptomatic, n = 13; asymptomatic, n = 33]). Vertical ground reaction force exerted on the ACLR limb was collected during walking gait, and functional analyses of variance were used to evaluate the effects of symptoms and time post-ACLR on vGRF throughout stance phase (α = 0.05).

RESULTS

Symptomatic individuals, <12 months post-ACLR, demonstrated less vGRF during both vGRF peaks (i.e., weight acceptance and propulsion) and greater vGRF during midstance, compared to asymptomatic individuals. Vertical ground reaction force characteristics were not different between symptomatic and asymptomatic individuals for most of stance in individuals between 12 and 24 months post-ACLR. Symptomatic individuals who were >24 months post-ACLR, exhibited greater vGRF during both peaks, but lesser vGRF during midstance, compared to asymptomatic individuals.

CONCLUSION

Relative to asymptomatic individuals, symptomatic individuals are more likely to underload the ACLR limb early after ACLR (i.e., <12 months) during both vGRF peaks, but overload the ACLR limb, during both vGRF peaks, at later time points (i.e., >24 months). We propose these differences in lower-extremity loading during walking might have implications for long-term knee health, and should be considered when designing therapeutic interventions for individuals with an ACLR.

Knee osteoarthritis risk is increased 4-6 fold after knee injury - a systematic review and meta-analysis

OBJECTIVE

To estimate knee osteoarthritis (OA) risk following anterior cruciate ligament (ACL), meniscus or combined ACL and meniscus injury.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, SPORTDiscus, CINAHL and Web of Science until November 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Prospective or retrospective studies with at least 2-year follow-up including adults with ACL injury, meniscal injury or combined injuries. Knee OA was defined by radiographs or clinical diagnosis and compared with the contralateral knee or non-injured controls.

STUDY APPRAISAL AND SYNTHESIS

Risk of bias was assessed using the SIGN50 checklist. ORs for developing knee OA were estimated using random effects meta-analysis.

RESULTS

53 studies totalling ∼1 million participants were included: 185 219 participants with ACL injury, mean age 28 years, 35% females, 98% surgically reconstructed; 83 267 participants with meniscal injury, mean age 38 years, 36% females, 22% confirmed meniscectomy and 73% unknown; 725 362 participants with combined injury, mean age 31 years, 26% females, 80% treated surgically. The OR of developing knee OA were 4.2 (95% CI 2.2 to 8.0; I²=92%), 6.3 (95% CI 3.8 to 10.5; I²=95%) and 6.4 (95% CI 4.9 to 8.3; I²=62%) for patients with ACL injury, meniscal injury and combined injuries, respectively.

CONCLUSION

The odds of developing knee OA following ACL injury are approximately four times higher compared with a non-injured knee. A meniscal injury and a combined injury affecting both the ACL and meniscus are associated with six times higher odds compared with a non-injured knee. Large inconsistency (eg, study design, follow-up period and comparator) and few high-quality studies suggest that future studies may change these estimates.

CLINICAL RELEVANCE

Patients sustaining a major knee injury have a substantially increased risk of developing knee OA, highlighting the importance of knee injury prevention programmes and secondary prevention strategies to prevent or delay knee OA development.PROSPERO registration number CRD42015016900.

[Treatment of degenerative meniscal lesions : From eminence to evidence-based medicine]

BACKGROUND

The treatment of degenerative meniscal lesions has received increased attention since the publication of several Level 1 studies over the last few years. The following review of literature including the consensus statement given by ESSKA reports on the management of patients with degenerative meniscal lesions.

MATERIAL AND METHODS

The analysis includes the literature of Level 1 to 4 studies and the statement of the consensus group of ESSKA concerning the surgical or conservative management of these patients.

RESULTS

Meniscal lesions cause progression in osteoarthritis. Patients presenting a combination of degenerative meniscal lesion and osteoarthritis show inferior clinical outcome. The average clinical outcome after surgical treatment was 70 points based on the Lysholm score. Level 1 studies show no difference in clinical outcome. However, over 30% of these patients require arthroscopy at the second stage after an interval of 3 to 6 months. Patients presenting a flap tear or complaining about mechanical symptoms show poor outcome after conservative treatment.

DISCUSSION

Level 1 studies have focused on very selected patients. These patients do not represent the daily practice of orthopaedic surgeons. The findings of the level 1 studies should, therefore, not be generalized. According to the consensus statement of ESSKA, the treatment of degenerative meniscal lesions should start with conservative management. In the case of persistent symptoms, surgery should be considered after 3 months. In the case of mechanical symptoms, arthroscopy might be indicated earlier. Arthroscopy in advanced osteoarthritic knees is not indicated due to inferior clinical outcome.

Scrutinizing the cut-off for "pathological" meniscal body extrusion on knee MRI

OBJECTIVES

Medial meniscal body extrusion ≥ 3 mm on MRI is often considered "pathologic." The aims of this study were to (1) assess the adequacy of 3 mm as cut-off for "pathological" extrusion and (2) find an optimal cut-off for meniscal extrusion cross-sectionally associated with radiographic knee osteoarthritis, bone marrow lesions (BMLs), and cartilage damage.

METHODS

Nine hundred fifty-eight persons, aged 50-90 years from Framingham, MA, USA, had readable 1.5 T MRI scans of the right knee for meniscal body extrusion (measured in mm). BMLs and cartilage damage were read using the whole organ magnetic resonance imaging score (WORMS). Knee X-rays were read according to the Kellgren and Lawrence (KL) scale. We evaluated the performance of the 3-mm cut-off with respect to the three outcomes and estimated a new cut-off maximizing the sum of sensitivity and specificity.

RESULTS

The study persons had mean age of 62.2 years, 57.0% were women and the mean body mass index was 28.5 kg/m2. Knees with radiographic osteoarthritis, BMLs, and cartilage damage had overall more meniscal extrusion than knees without. The 3-mm cut-off had moderate sensitivity and low specificity for all three outcomes (sensitivity between 0.68 [95% CI 0.63-0.73] and 0.81 [0.73-0.87], specificity between 0.49 [0.45-0.52] and 0.54 [0.49-0.58]). Using 4 mm maximized the sum of sensitivity and specificity and improved the percentage of correctly classified subjects (from between 54 and 61% to between 64 and 79%).

CONCLUSIONS

The 4-mm cut-off may be used as an alternative cut-off for denoting pathological meniscal extrusion.

KEY POINTS

• Medial meniscal body extrusion is strongly associated with osteoarthritis. • The 3-mm cut-off for medial meniscal body extrusion has high sensitivity but low specificity with respect to bone marrow lesions, cartilage damage, and radiographic osteoarthritis. • The 4-mm cut-off maximizes the sensitivity and specificity with respect to all three osteoarthritis features.

Meniscal body extrusion and cartilage coverage in middle-aged and elderly without radiographic knee osteoarthritis

OBJECTIVES

To determine meniscal extrusion and cartilage coverage on magnetic resonance (MR) images and factors associated with these parameters in knees of middle-aged and elderly persons free from radiographic tibiofemoral osteoarthritis (OA).

METHODS

Seven hundred eighteen persons, free of radiographic tibiofemoral OA, aged 50-90 years from Framingham, MA, USA, were included. We measured meniscal extrusion on 1.5 T MRI of both knees to evaluate both medial and lateral meniscal body extrusion and cartilage coverage. We also determined meniscal morphology and structural integrity. The multivariable association with age, body mass index (BMI), and ipsilateral meniscal damage was also evaluated.

RESULTS

The mean meniscal body extrusion medially was 2.7 mm and laterally 1.8 mm. The tibial cartilage coverage was about 30% of ipsilateral cartilage surface (both compartments). The presence of ipsilateral meniscal damage was associated with more extrusion in only the medial compartment, 1.0 mm in men and 0.6 mm in women, and less cartilage coverage proportion, -5.5% in men and -4.6% in women.

CONCLUSIONS

Mean medial meniscal body extrusion in middle-aged or older persons without radiographic tibiofemoral OA approximates the commonly used cutoff (3 mm) to denote pathological extrusion. Medial meniscal damage is a factor associated with medial meniscal body extrusion and less cartilage coverage.

KEY POINTS

• Medial meniscal extrusion in middle-aged/older persons without OA is around 3 mm. • Lateral meniscal extrusion in middle-aged/older persons without OA is around 2 mm. • Meniscal damage is associated with medial meniscal extrusion and less cartilage coverage.

Morphological and ultrastructural analysis of normal, injured and osteoarthritic human knee menisci

The human meniscus plays a crucial role for transmission and distribution of load across the knee, as well as shock absorption, joint stability, lubrication, and congruity. The aim of this study was to compare the complex geometry, and unique ultrastructure and tissue composition of the meniscus in healthy (control) and pathological conditions to provide understanding of structural changes that could be helpful in the future design of targetted therapies and improvement of treatment indications. We analyzed meniscus samples collected from 3 healthy multi-organ donors (median age, 66 years), 5 patients with traumatic meniscal tear (median age, 41 years) and 3 patients undergoing total knee replacement (TKR) for end-stage osteoarthritis (OA) (median age, 72 years). We evaluated the extracellular matrix (ECM) organization, the appearance and distribution of areas of calcification, and modifications of cellular organization and structure by electron microscopy and histology. The ECM structure was similar in specimens from traumatic meniscus tears compared to those from patients with late-stage OA, showing disorganization of collagen fibers and increased proteoglycan content. Cells of healthy menisci showed mainly diffuse chromatin and well preserved organelles. Both in traumatic and in OA menisci, we observed increased chromatin condensation, organelle degeneration, and cytoplasmic vacuolization, a portion of which contained markers of autophagic vacuoles. Areas of calcification were also observed in both traumatic and OA menisci, as well as apoptotic- like features that were particularly prominent in traumatic meniscal tear samples. We conclude that meniscal tissue from patients with traumatic meniscal injury demonstrate pathological alterations characteristic of tissue from older patients undergoing TKR, suggesting that they have high susceptibility to develop OA.

Effect of Lower Limb Alignment in Medial Meniscus-Deficient Knees on Tibiofemoral Contact Pressure

Background:

Degenerative medial meniscal tears and subsequent partial meniscal resection compromise meniscal function and lead to an overload of the medial compartment. In addition, lower limb alignment plays a key role in load distribution between the medial and lateral knee compartments, and varus alignment is a potential risk factor for medial osteoarthritis.

Purpose/Hypothesis:

The purpose of this biomechanical study was to investigate the effect of valgus and varus alignment on peak pressure and contact area in knees with concomitant horizontal medial meniscal tears and subsequent leaflet resection. It was hypothesized that varus alignment in combination with meniscal loss leads to the highest peak pressure within the medial compartment.

Study Design:

Controlled laboratory study.

Methods:

Six fresh-frozen human cadaveric knees were axially loaded using a 1000-N compressive load in full extension with the mechanical axis rotated to intersect the tibial plateau at 40%, 45%, 50%, 55%, and 60% of its width (TPW) to simulate varus and valgus alignment. Tibiofemoral peak contact pressure and contact area of the medial and lateral compartments were determined using pressure-sensitive foils in each of 4 different meniscal conditions: intact, 15-mm horizontal tear of the posterior horn, inferior leaflet resection, and resection of both leaflets.

Results:

The effect of alignment on peak pressure (normalized to the neutral axis) within the medial compartment in cases of an intact meniscus was measured as follows: varus shift resulted in a mean increase in peak pressure of 18.5% at 45% of the TPW and 37.4% at 40% of the TPW, whereas valgus shift led to a mean decrease in peak pressure of 8.7% at 55% of the TPW and 23.1% at 60% of the TPW. Peak pressure changes between the intact meniscus and resection within the medial compartment was less in valgus-aligned knees (0.21 MPa at 60% TPW, 0.59 MPa at 50% TPW, and 0.76 MPa at 40% TPW). Contact area was significantly reduced after partial meniscal resection in the neutral axis (intact, 553.5 ± 87.6 mm²; resection of both leaflets, 323.3 ± 84.2 mm²; P < .001). This finding was consistent in any alignment.

Conclusion:

Both partial medial meniscal resection and varus alignment led to an increase in medial compartment peak pressure. Valgus alignment prevented medial overloading by decreasing contact pressure even after partial meniscal resection. A horizontal meniscal tear did not influence peak pressure and contact area even in varus alignment.

Clinical Relevance:

As a clinical consequence, partial meniscal resection should be avoided to maintain the original biomechanical behavior, and the mechanical axis should be taken into account if partial meniscectomy is necessary.

Outcomes of Arthroscopic Posterior Medial Meniscus Root Repair: Association With Body Mass Index

INTRODUCTION

The purpose of this study was to assess the association of outcomes from posterior medial meniscus root repairs with patient age, sex, and body mass index (BMI).

METHODS

Patients who underwent arthroscopic posterior medial meniscus root repair completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) and reported subsequent surgeries. The association of patient factors with subsequent surgery and clinical osteoarthritis (OA) based on the KOOS score was evaluated.

RESULTS

Minimum 2-year follow-up was available on 22/25 patients (88%). Two patients (9.1%) had subsequent surgeries, and 10 (45.5%) met the KOOS criteria for OA. A BMI over 35 kg/m was associated with repeat surgery (25% versus 0%; P = 0.049) and clinical OA (75% versus 28.6%; P = 0.035).

CONCLUSION

Although arthroscopic repair of posterior medial root tears has good clinical outcomes and a low rate of subsequent surgery, an elevated BMI level is associated with worse clinical outcomes and a higher rate of subsequent surgery.

Introduction of an MR-based semi-quantitative score for assessing partial meniscectomy and relation to knee joint degenerative disease: data from the Osteoarthritis Initiative

OBJECTIVES

To develop an MR-based semi-quantitative meniscus scoring technique for postoperative assessment of the degree of meniscal resection, to test its reproducibility, and to study the relationship between the amount of resection and degenerative disease burden.

METHODS

We studied the right knee of 135 participants from the Osteoarthritis Initiative that underwent meniscal surgery an average of 14 years previously. The amount of meniscal resection was assessed on baseline 3.0-T MRIs and calculated as meniscus resection score (MenRS) with a range of 0 to 18. Knee abnormalities at baseline and 48 months were graded using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). Subjects were also stratified according to meniscal resection performed after injury versus without preceding injury. Statistical analysis included intra-class correlation coefficient (ICC) to determine reproducibility as well as regression models and partial correlations to correlate MenRS with WORMS outcomes.

RESULTS

ICC values for intra- and inter-observer reproducibility of MenRS were 0.980 and 0.977, respectively. Overall, the amount of meniscal resection showed a significant correlation with baseline WORMS grades: higher MenRS was associated with higher total WORMS grades (p = 0.004) and cartilage (p = 0.004) and ligament (p < 0.001) subscores. However, no significant association between MenRS and change in WORMS grades over 48 months was found. The relationship between MenRS and baseline WORMS grades did not change after adjusting for a reported history of knee injury.

CONCLUSIONS

Postoperative assessment of the knee following partial meniscectomy using the newly developed MenRS showed excellent reproducibility and significant cross-sectional correlation with WORMS gradings.

KEY POINTS

• The newly developed semi-quantitative MR-based meniscal resection score demonstrated excellent reproducibility. • A significant correlation between the amount of meniscal resection measured using the newly developed score and the degree of overall knee joint degenerative disease and cartilage defects was found.

A collagen-coated sponge silk scaffold for functional meniscus regeneration

Tissue engineering is a promising solution for meniscal regeneration after meniscectomy. However, in situ reconstruction still poses a formidable challenge due to multifunctional roles of the meniscus in the knee. In this study, we fabricate a silk sponge from 9% (w/v) silk fibroin solution through freeze drying and then coat its internal space and external surface with collagen sponge. Subsequently, various characteristics of the silk-collagen scaffold are evaluated, and cytocompatibility of the construct is assessed in vitro and subcutaneously. The efficacy of this composite scaffold for meniscal regeneration is evaluated through meniscus reconstruction in a rabbit meniscectomy model. It is found that the internally coated collagen sponge enhances the cytocompatibility of the silk sponge, and the external layer of collagen sponge significantly improves the initial frictional property. Additionally, the silk-collagen composite group shows more tissue ingrowth and less cartilage wear than the pure silk sponge group at 3 months postimplantation in situ. These findings thus demonstrate that the composite scaffold had less damage to the joint surface than the silk alone through promoting functional meniscal regeneration after meniscectomy, which indicates its clinical potential in meniscus reconstruction.

High short-term return to sports rate despite an ongoing healing process after acute meniscus repair in young athletes

PURPOSE

Acute meniscus repair in young athletes is always a challenge due to the long rehabilitation process and time to return to sport (RTS). The purpose was to investigate signal alterations in short-term follow-up after acute meniscus repair on specific magnetic resonance imaging (MRI) scan sequences. It was hypothesized that (1) MRI signal changes over the first postoperative healing phase and represent a continuous healing process and (2) meniscus healing properties correlates with clinical outcomes and RTS.

METHODS

Young athletes with traumatic meniscus lesion and arthroscopic meniscus repair within 6 weeks and available preoperative MRI were enrolled. Clinical examination, outcome scores (IKDC, KOOS, Lysholm Score, Tegner activity score) and RTS were surveyed preoperatively and 6 and 12 weeks and 6 months after surgery. Radiological follow-up examinations were performed 2, 4, 6, 12 weeks and 6 months after operation using a 3T-MRI. Evaluation was based on ISAKOS meniscus classification system, meniscus healing were classified according to Henning's criteria.

RESULTS

At final follow-up (FU) 30 patients (28 month, 2 week) with a total of 35 meniscus tears (19 medial, 16 lateral) were included. Clinical scores improved significantly after surgery: IKDC Score (preOP: 39.4 ± 18.5, final FU: 78.8 ± 15.3) KOOS (preOP: 45.7 ± 22.1, final FU: 82.7 ± 12.5) and Lysholm Score (preOP: 42.8 ± 23.7, final FU: 84.4 ± 13.8) (p < 0.01). Tegner activity score showed a steadily increase to 4 (range 3-9) at 6 months but did not reached the pre-injury level of 6 (range 3-9). RTS rate was 100% whereof 44.8% reached their pre-injury level. MRI examination revealed a continuous healing process and menisci were classified as 55.9% healed, 35.3% partially healed and 8.8% non-healed at final FU.

CONCLUSION

This study showed that MRI signal alterations of the meniscus steadily occur within the first 6 months postoperatively. MRI reveals an ongoing healing process at final FU that have to be carefully considered when RTS is discussed with high demanding patients. However, young athletes provide good clinical results and RTS rate even though MRI alterations are still present.

LEVEL OF EVIDENCE

Therapeutic study, prospective case series, Level IV.

Meniscal allograft transplantation after meniscectomy: clinical effectiveness and cost-effectiveness

PURPOSE

To assess the clinical effectiveness and cost-effectiveness of meniscal allograft transplantation (MAT) after meniscal injury and subsequent meniscectomy.

METHODS

Systematic review of clinical effectiveness and cost-effectiveness analysis.

RESULTS

There is considerable evidence from observational studies, of improvement in symptoms after meniscal allograft transplantation, but we found only one small pilot trial with a randomised comparison with a control group that received non-surgical care. MAT has not yet been proven to be chondroprotective. Cost-effectiveness analysis is not possible due to a lack of data on the effectiveness of MAT compared to non-surgical care.

CONCLUSION

The benefits of MAT include symptomatic relief and restoration of at least some previous activities, which will be reflected in utility values and hence in quality-adjusted life years, and in the longer term, prevention or delay of osteoarthritis, and avoidance or postponement of some knee replacements, with resulting savings. It is likely to be cost-effective, but this cannot be proven on the basis of present evidence.

LEVEL OF EVIDENCE

IV.

Likelihood of knee replacement surgery up to 15 years after sports injury: A population-level data linkage study

OBJECTIVES

Knee injury is strongly associated with the development of knee osteoarthritis. While there is preliminary evidence for an increased risk of knee replacement (KR) surgery after sports injury, no studies have investigated this at a population level. This population-level study aimed to quantify the likelihood of KR surgery and direct healthcare costs 10-15 years after sports injury.

DESIGN

Statewide population-based cohort study.

METHODS

The cohort was established by linking two key administrative datasets capturing all hospital admissions and emergency department (ED) presentations in Victoria, Australia. Sports injury presentations from 2000-2005 and KR admissions from 2000-2015 were identified using ICD-10-AM codes. A Cox proportional hazards model estimated likelihood of KR using time to surgery admission data, adjusting for potential confounders. KR costs for the sports-injured cohort were estimated from the health system perspective using diagnosis codes and national hospital cost weights.

RESULTS

Over the study period there were 64,038 sports injuries (including 7205 knee injuries) resulting in ED presentation or hospitalisation, and 326 KR procedures. Multivariate analysis showed that having a knee injury more than doubled the hazard of subsequent KR (hazard ratio 2.41, 95%CI 1.73-3.37), compared to all other sports injuries. Direct healthcare costs for KR totaled $AUD7.93 million for the cohort, with 21% of costs attributable to the knee injury group.

CONCLUSIONS

Sports-related knee injury manifests in a significantly greater likelihood of KR, at considerable cost to society. Targeted health policy and effective interventions are needed to prevent sports-related knee injuries and contain this substantial burden.

Evaluating meniscus allograft transplant using a cost-effectiveness threshold analysis

BACKGROUND

It is unknown if meniscal allograft transplant (MAT) delays progression of osteoarthritis (OA). Cost-effectiveness threshold analysis can demonstrate the necessary delay in OA progression required by MAT to be considered cost-effective compared to non-operative management. The purpose of this study is to identify the efficacy MAT requires in delaying progression to OA in previously meniscectomized knees in order to be considered cost-effective compared to non-operative treatment. A secondary goal is to demonstrate the influence of age and BMI on the required efficacy of MAT for cost-effectiveness.

METHODS

A Markov model was developed to evaluate the cost-effectiveness of MAT compared to non-operative management for patients with prior meniscectomy. Input parameters were identified in existing literature. Cost was derived from literature and The PearlDiver Patient Records Database. The required rate of OA progression was compared across treatment modalities to determine how effective MAT is required to be cost-effective.

RESULTS

MAT needs to be 31% more effective in delaying OA compared to non-operative interventions in order to be cost-effective. MAT is most cost-effective in 20-29 year-old patients, requiring a 25% greater efficacy in delaying OA. Obesity (BMI 30-35) makes MAT less cost-effective when compared to non-obese patients; however, the difference in required efficacy in delaying OA among obese patient when compared to non-operative management is approximately 10%.

CONCLUSIONS

MAT needs to be approximately one-third more effective in delaying OA in previously meniscectomized knees to be considered cost-effective. Younger, non-obese patients have the lowest required efficacy of MAT to be cost-effective.

Innovative treatment of clinically diagnosed meniscal tears: a randomized sham-controlled trial of the Mulligan concept 'squeeze' technique

Objective: The purpose of this study was to assess the effects of the Mulligan Concept (MC) 'squeeze' technique compared to a sham technique in participants with a clinically diagnosed meniscal tear.

Methods: A multi-site randomized sham-controlled trial of participants (n = 23), aged 24.91 ± 12.09 years, with a clinically diagnosed meniscal tear were equally and randomly divided into two groups. Groups received a maximum of six treatments over 14 days. Patient outcomes included the numeric pain rating scale (NRS), patient-specific functional scale (PSFS), the disablement in the physically active (DPA) scale and the knee injury osteoarthritis outcome score. Data were analysed using univariate ANOVA, univariate ANCOVA, and descriptive statistics.

Results: All participants in the MC 'squeeze' group met the discharge criteria of ≤2 points on the NRS, ≥9 points on the PSFS, and ≤34 points or ≤23 on the DPA Scale for chronic or acute injuries, respectively within the treatment intervention timeframe. A significant difference was found in favor of the MC 'squeeze' technique in PSFS scores (F(1, 21) = 4.40, p = .048, partial eta squared = .17, observed power = .52) and in DPA Scale scores (F(1, 21) = 7.46, p = .013, partial eta squared = .27, observed power = .74).

Discussion: The results indicate the MC 'squeeze' technique had positive effects on patient function and health-related quality of life over a period of 14 days and was clinically and statistically superior to the sham treatment. Further investigation of the MC 'squeeze' technique is warranted.

Walking gait asymmetries 6 months following anterior cruciate ligament reconstruction predict 12-month patient-reported outcomes

The study sought to determine the association between gait biomechanics (vertical ground reaction force [vGRF], vGRF loading rate [vGRF-LR]) collected 6 months following anterior cruciate ligament reconstruction (ACLR) with patient-reported outcomes at 12 months following ACLR. Walking gait biomechanics and all subsections of the Knee Injury and Osteoarthritis Outcomes Score (KOOS) were collected at 6 and 12 months following ACLR, respectively, in 25 individuals with a unilateral ACLR. Peak vGRF and peak instantaneous vGRF-LR were extracted from the first 50% of the stance phase. Limb symmetry indices (LSI) were used to normalize outcomes in the ACLR limb to that of the uninjured limb (ACLR/uninjured). Linear regression analyses were used to determine associations between biomechanical outcomes and KOOS while accounting for walking speed. Receiver operator characteristic curves were used to determine the accuracy of 6-month biomechanical outcomes for identifying individuals with acceptable patient-reported outcomes, using previously defined KOOS cut-off scores, 12 months post-ACLR. Individuals with lower peak vGRF LSI 6 months post-ACLR demonstrated worse patient-reported outcomes (KOOS Pain, Activities of Daily life, Sport and Recreation, Quality of Life) at the 12-month exam. A peak vGRF LSI ≥0.99 6 months following ACLR associated with 13.33× higher odds of reporting acceptable patient-reported outcomes 12 months post-ACLR. Lesser peak vGRF LSI during walking at 6-months post-ACLR may be a critical indicator of worse future patient-reported outcomes. Clinical significance achieving early symmetrical lower extremity loading and minimizing under-loading of the ACLR limb during walking may be a potential therapeutic target for improving patient-reported outcomes post-ACLR. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2932-2940, 2018.

A quantitative metric for knee osteoarthritis: reference values of joint space loss

OBJECTIVES

Knee osteoarthritis (OA) onset and progression has been defined with transitions in Kellgren-Lawrence (KL) grade or Osteoarthritis Research Society International (OARSI) Joint Space Narrowing (JSN) grade. We quantitatively describe one-year transitions in KL grade and JSN, using fixed joint space width (fJSW), among knees with or at risk of OA.

METHODS

Radiographic assessments from the Osteoarthritis Initiative (OAI) were used to identify transitions in KLG and JSN grade between consecutive annual visits. The fJSW was measured in the medial and lateral compartments. The distribution of change in fJSW for KLG and JSN transitions were described, and mean change in fJSW was estimated using mixed models.

RESULTS

KL grade and JSN scores were available for about 20,000 annual transitions from 6047 knees contributed by 3389 participants. Knees that remained stable in KL or OARSI-JSN over 1 year had mean medial fJSW loss between -0.06 and -0.19 mm/year. Transition from KL grade 0 to 1, 0 to 2, and KL 1 to 2 were similar with respect to mean medial fJSW loss (0.18-0.28 mm). Greatest annual changes in medial fJSW corresponded to KL 0 to 3 (1.62 mm), KL 2 to 4 (1.23 mm) and JSN 0 to 2 (1.85 mm).

CONCLUSIONS

Anchoring quantitatively measured loss of joint space width to transitions in KL grade and JSN provides reference values based on traditional definitions of knee OA onset and progression.

Towards secondary prevention of early knee osteoarthritis

Osteoarthritis (OA) of the knee is the most common arthritic disease, yet a convincing drug treatment is not available. The current narrative review focuses on integration of scientific evidence and professional experience to illustrate which management approaches can be taken for prototypical individual patient profiles with early knee OA. Animal models suggest that: (1) OA can progress even in the presence of fully recovered movement kinetics, kinematics and muscle activation patterns; (2) muscle weakness is an independent risk factor for the onset and possibly the rate of progression of knee OA; (3) onset and progression of OA are not related to body weight but appear to depend on the percentage of body fat. From studies in the human model, one could postulate that risk factors associated with progression of knee OA include genetic traits, preceding traumatic events, obesity, intensity of pain at baseline, static and dynamic joint malalignment and reduced muscle strength. Taken this into account, an individual can be identified as early knee OA at high risk for disease progression. A holistic patient-tailored management including education, supportive medication, weight loss, exercise therapy (aerobic, strengthening and neuromuscular) and behavioural approaches to improve self-management of early knee OA is discussed in individual prototypic patients. Secondary prevention of early knee OA provides a window of opportunity to slow down or even reverse the disease process. Yet, as the sheer number of patients early in the OA disease process is probably large, a more structured approach is needed to provide appropriate care depending on the patient's individual risk profile.

Poor outcome after a surgically treated chondral injury on the medial femoral condyle: early evaluation with dGEMRIC and 17-year radiographic and clinical follow-up in 16 knees

Background and purpose - The optimal treatment for traumatic cartilage injuries remains unknown. Contrast-enhanced MRI of cartilage (dGEMRIC) evaluates cartilage quality and a low dGEMRIC index may predict radiographic osteoarthritis (OA). The purpose of this study was (a) to explore the results 17 years after surgical treatment of an isolated cartilage knee injury and (b) to evaluate the predictive value of dGEMRIC. Patients and methods - 16 knees with an isolated traumatic cartilage injury of the medial femoral condyle had cartilage repair surgery either by microfracture or autologous cartilage implantation. dGEMRIC of the injured knee was performed 2 years after surgery and radiographic examinations were performed 17 years after the operation. Results - Radiographic OA was present in 12 of 16 knees. Irrespective of surgical method, the dGEMRIC index was lower in repair tissue compared with adjacent cartilage in the medial compartment, 237 ms vs. 312 ms (p < 0.001), which in turn had lower value than in the non-injured lateral cartilage, 312 ms vs. 354 ms (p < 0.008). The dGEMRIC index in the cartilage adjacent to the repair tissue correlated negatively with radiographic osteophyte score, r = -0.75 (p = 0.03). Interpretation - A traumatic cartilage injury is associated with a high prevalence of OA after 17 years. The low dGEMRIC index in the repair tissue 2 years postoperatively indicates fibrocartilage of low quality. The negative correlation between the dGEMRIC index in the adjacent cartilage and future OA suggests that the quality of the surrounding cartilage influences outcome after cartilage repair surgery.

Select Biomarkers on the Day of Anterior Cruciate Ligament Reconstruction Predict Poor Patient-Reported Outcomes at 2-Year Follow-Up: A Pilot Study

Background

The majority of patients develop posttraumatic osteoarthritis within 15 years of anterior cruciate ligament (ACL) injury. Inflammatory and chondrodegenerative biomarkers have been associated with both pain and the progression of osteoarthritis; however, it remains unclear if preoperative biomarkers differ for patients with inferior postoperative outcomes.

Hypothesis/Purpose

The purpose of this pilot study was to compare biomarkers collected on the day of ACL reconstruction between patients with “good” or “poor” 2-year postoperative outcomes. We hypothesized that inflammatory cytokines and chondrodegenerative biomarker concentrations would be significantly greater in patients with poorer outcomes.

Study Design

Prospective cohort design.

Methods

22 patients (9 females, 13 males; age = 19.5 ± 4.1 years; BMI = 24.1 ± 3.6 kg/m²) previously enrolled in a randomized trial evaluating early anti-inflammatory treatment after ACL injury. Biomarkers of chondrodegeneration and inflammation were assessed from synovial fluid (sf) samples collected on the day of ACL reconstruction. Participants completed Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) questionnaires two years following surgery. Patients were then categorized based on whether their KOOS Quality of Life (QOL) score surpassed the Patient Acceptable Symptom State (PASS) threshold of 62.5 points or the IKDC PASS threshold of 75.9 points.

Results

Patients that failed to reach the QOL PASS threshold after surgery (n = 6, 27%) had significantly greater sf interleukin-1 alpha (IL-1α; p = 0.004), IL-1 receptor antagonist (IL-1ra; p = 0.03), and matrix metalloproteinase-9 (MMP-9; p = 0.01) concentrations on the day of surgery. Patients that failed to reach the IKDC PASS threshold (n = 9, 41%) had significantly greater sf IL-1α (p = 0.02).

Conclusion

These pilot data suggest that initial biochemical changes after injury may be an indicator of poor outcomes that are not mitigated by surgical stabilization alone. Biological adjuvant treatment in addition to ACL reconstruction may be beneficial; however, these data should be used for hypothesis generation and more definitive randomized clinical trials are necessary.

Relation of meniscus pathology to prevalence and worsening of patellofemoral joint osteoarthritis: the Multicenter Osteoarthritis Study

OBJECTIVE

To determine the relationship of meniscal damage to magnetic resonance imaging (MRI) features of compartment-specific patellofemoral joint (PFJ) osteoarthritis (OA) at baseline and 2 years later.

METHOD

Individuals from a prospective cohort of individuals aged 50-79 with or at risk of knee OA were included. At the 60-month and 84-month study visit, Whole-Organ MRI Score (WORMS) was used to assess meniscal tears and extrusions as well as cartilage damage and bone marrow lesions (BMLs) in the medial and lateral patella and trochlea. Worsening of structural features was defined as any increase in WORMS score from 60 to 84 months. Logistic regression was used to determine the cross-sectional and longitudinal relation of meniscus damage to features of compartment-specific PFJ OA.

RESULTS

Relative to knees without lateral meniscal pathology at baseline, those with grades 3-4 lateral meniscal tear and extrusion had greater risk of worsening of cartilage damage in the lateral PFJ 2 years later (Risk ratio: 1.7 [95% CI: 1.1-2.7) and (1.7 [1.2-2.5]), respectively. Relative to those without medial meniscal pathology at baseline, those with grades 1-2 (0.6 [0.4-0.9]) and 3-4 (0.7 [0.5-1.0]) medial meniscal tears had lower risk of worsening of BMLs in the medial PFJ 2 years later.

CONCLUSION

Meniscal tear and extrusion are associated with increased risk of medial and lateral PFJ OA and more severe meniscal pathology is associated with worsening of PFJ OA 2 years later. Lateral meniscal pathology appears to be more detrimental to the lateral PFJ.

Decision to Return to Sport Participation After Anterior Cruciate Ligament Reconstruction, Part II: Self-Reported and Functional Performance Outcomes

CONTEXT

  Anterior cruciate ligament (ACL) reconstruction (ACLR) is the most commonly used method for helping athletes regain function and return to preinjury activity levels after ACL injury. Outcomes after ACLR have suggested that athletes return to a level of function that would support a return to sport participation; however, in a recent meta-analysis, pooled return rates were only 55%. It is unclear whether this discrepancy is a result of functional impairments.

OBJECTIVE

  To compare patient-reported outcomes (PROs), dynamic balance, dynamic functional performance, strength, and muscular endurance in athletes who returned to sport (RTS) and athletes who did not return to sport (NRTS) after ACLR.

DESIGN

  Case-control study.

SETTING

  University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Two groups of participants with primary unilateral ACLR: 18 RTS individuals (7 males, 11 females; age = 23 ± 11 years, height = 163.58 ± 40.41 cm, mass = 70.00 ± 21.75 kg, time since surgery = 4.02 ± 3.20 years) and 12 NRTS individuals (5 males, 7 females; age = 26 ± 13 years, height = 171.33 ± 48.24 cm, mass = 72.00 ± 21.81 kg, time since surgery = 3.68 ± 2.71 years).

INTERVENTION(S)

  The PROs consisted of the International Knee Documentation Committee Subjective Knee Evaluation Form, Knee Injury and Osteoarthritis Outcome Score, Tegner Activity Scale, and Marx Activity Scale. Functional performance outcome measures were the anterior and posteromedial reach on the Star Excursion Balance Test, a battery of single-legged-hop tests, isokinetic quadriceps and hamstrings strength at 60°/s and 180°/s, and a novel step-down-to-fatigue test. All measures were taken during a single laboratory session.

MAIN OUTCOME MEASURE(S)

  The Limb Symmetry Index was calculated for all functional performance measures. Mann-Whitney U tests were used to compare measures between groups ( P < .10).

RESULTS

  Compared with the RTS group, the NRTS group had lower scores on the International Knee Documentation Committee Subjective Knee Evaluation Form (RTS median = 92.52, range = 66.67-97.70; NRTS median = 82.76, range = 63.22-96.55; P = .03) and Knee Injury and Osteoarthritis Outcome Score Symptoms subscale (RTS median = 88, range = 54-100; NRTS median = 71, range = 54-100; P = .08). No differences were observed for any functional performance measures.

CONCLUSIONS

  The NRTS athletes displayed lower PROs despite demonstrating similar function on a variety of physical performance measures. These results further support existing evidence that physical performance alone may not be the ideal postoperative outcome measure. Measures of patients' symptoms and self-perceived physical function may also greatly influence postoperative activity choices.

Magnetic Resonance Imaging and Functional Outcomes After a Polyurethane Meniscal Scaffold Implantation: Minimum 5-Year Follow-up

PURPOSE

To report the magnetic resonance imaging (MRI) and clinical outcomes at a minimum 5-year follow-up in a series of patients with postmeniscectomy syndrome and treated with a polyurethane scaffold.

METHODS

All consecutive patients operated on from September 2008 to February 2011 for either persistent medial or lateral joint line compartmental pain receiving a polyurethane scaffold due to a previous partial meniscus resection with a minimum 5-year follow-up were included. Functional scores (Knee Injury and Osteoarthritis Outcomes Score, International Knee Documentation Committee, Lysholm, and Tegner) were assessed preoperatively and at the last follow-up. The state of the scaffold as well as postoperative scaffold extrusion and the total remaining meniscal volume was also evaluated in MRI.

RESULTS

Thirty-two patients were included. The mean follow-up was 70.8 ± 7.5 months. The functionality of the knees improved in all the scores used (P < .001) except for the Tegner score that stayed steady. Most of meniscal implants showed extrusion of 2.4 mm (95% confidence interval [CI], 1.1-3.7) were smaller and a hyperintensity signal was seen in the MRI. Three scaffolds were resorbed at the last follow-up. The meniscal volume, determined by MRI, was 1.14 cm³ (95% CI, 0.96-1.31) preoperatively and 1.61 cm³ (95% CI, 1.43-1.7) at the last follow-up. No differences were presented.

CONCLUSIONS

The use of a polyurethane meniscal scaffold in patients with a symptomatic meniscus deficit had a good functional outcome at 5 years after surgery. However, the implanted scaffolds did not present normal meniscal tissue with MRI, and the implant volume was considerably less than expected. The fact that most of patients included received different concomitant procedures during scaffold implantation introduces a degree of performance bias into the results.

LEVEL OF EVIDENCE

Level IV, case series.

The role of meniscal repair for prevention of early onset of osteoarthritis

BACKGROUND

The meniscus plays an important role in the integrity of the knee joint. Therefore, meniscus tissue preserving techniques for the therapy of meniscus injuries seem to be reasonable. One of the important questions is whether meniscal repair can prevent the knee joint from early onset of osteoarthritis.

METHODS

According to the review of the current literature, the principles of a successful meniscal repair are explained and the functional outcome and its impact on the prevention of osteoarthritis are analyzed in this article.

RESULTS

Current data show a positive impact of a successful meniscus repair on the functional outcome in long-term. By this a protective effect on the development of osteoarthritis via the repair of meniscus lesions to restore the meniscus integrity can be confirmed. However, higher rates of re-operations in context to meniscus suturing have to be considered.

CONCLUSION

Due to the improved functional outcomes as well as preventive effect on the development of osteoarthritis within the knee joint in long-term, it is of importance to preserve as much meniscus tissue as possible in meniscus therapy. Patients previously have to be informed about the higher revision rate in context to meniscus suturing.

Assessment of meniscus with adiabatic T1ρ and T2ρ relaxation time in asymptomatic subjects and patients with mild osteoarthritis: a feasibility study

OBJECTIVE

To investigate the ability of magnetic resonance imaging (MRI) adiabatic relaxation times in the rotating frame (adiabatic T_1ρ and T_2ρ) to detect structural alterations in meniscus tissue of mild OA patients and asymptomatic volunteers.

METHOD

MR images of 24 subjects (age range: 50-67 years, 12 male), including 12 patients with mild osteoarthritis (OA) (Kellgren-Lawrence (KL) = 1, 2) and 12 asymptomatic volunteers, were acquired using a 3 T clinical MRI system. Morphological assessment was performed using semiquantitative MRI OA Knee Score (MOAKS). Adiabatic T_1ρ and T_2ρ (AdT_1ρ, AdT_2ρ) relaxation time maps were calculated in regions of interest (ROIs) containing medial and lateral horns of menisci. The median relaxation time values of the ROIs were compared between subjects classified based on radiographic findings and MOAKS evaluations.

RESULTS

MOAKS assessment of patients and volunteers indicated the presence of meniscal and cartilage lesions in both groups. For the combined cohort group, prolonged AdT_1ρ was observed in the posterior horn of the medial meniscus (PHMED) in subjects with MOAKS meniscal tear (P < 0.05). AdT_2ρ was statistically significantly longer in PHMED of subjects with MOAKS full-thickness cartilage loss (P < 0.05). After adjusting for multiple comparisons, differences in medians of observed AdT_1ρ and AdT_2ρ values between mild OA patients and asymptomatic volunteers did not reach statistical significance.

CONCLUSION

AdT_1ρ and AdT_2ρ measurements have the potential to identify changes in structural composition of meniscus tissue associated with meniscal tear and cartilage loss in a cohort group of mild OA patients and asymptomatic volunteers.

Anterior Cruciate Ligament Transection-Induced Cellular and Extracellular Events in Menisci: Implications for Osteoarthritis

BACKGROUND

The meniscus plays an important role in knee joint diseases such as osteoarthritis (OA). Meniscal injuries can be accompanied by joint catabolic events initiated by inflammation, leading to articular cartilage destruction, but the cellular events responsible for intrinsic meniscal injury and the extracellular matrix changes necessary for meniscal degradation are not well known.

PURPOSE

To explore the cellular and matrix-related changes of menisci based on a mouse OA model of anterior cruciate ligament transection (ACLT).

STUDY DESIGN

Controlled laboratory study.

METHODS

A mouse ACLT OA model was established by transection of anterior cruciate ligaments on the right knee joints of 8-week-old male (n = 34) and female (n = 34) C57 mice. The knee joints were collected at 1, 2, 4, and 8 weeks after ACLT surgery, and the meniscal changes were analyzed by radiography, histology, immunohistochemistry, immunoblot, and quantitative real-time polymerase chain reaction.

RESULTS

The deterioration of menisci was more extensive than that of articular cartilage and subchondral bone at 4 weeks after ACLT surgery. The rapid loss of collagen II and Sox9 in chondrocyte-like cells in the white-white zone of menisci was confirmed, and the activation of potential meniscus progenitor cells and chondroblasts was identified based on the increase of CD90, CD105, and Runx2. Further, the intrinsic inflammation in the bone marrow-like zone of menisci was activated by enhancement of dendritic cells (CD11c⁺), T cells (CD3⁺), and macrophages (F4/80⁺) with the increase of the inflammatory factors interleukin 1β and tumor necrosis factor α. Finally, the extracellular matrix events involving changes in chemokines, increases of matrix proteases (matrix metalloproteinases and ADAMTS5), and decreases of lysyl oxidase family were elucidated.

CONCLUSION

ACLT-induced meniscal changes not only could explain the contribution of the meniscus to the progress of OA but also could provide a cue for initiation of preventive treatments in the early stages of OA.

CLINICAL RELEVANCE

This study provides support for better protection of menisci in ACL injury-induced conditions such as OA and indicates that menisci should be considered in the development of clinical pharmacological interventions.

Arthroscopic direct meniscal extrusion reduction: surgical tips to reduce persistent meniscal extrusion in meniscal root repair

Meniscal extrusion (ME) is defined as extension of the meniscal margin by at least 3 mm beyond the tibial margin. The main purpose of meniscal root repair is to restore the anatomy and function of the meniscus. Therefore, the reduction in the ME is one of the important objective outcomes. Nevertheless, the reduced meniscal extrusion was obtained in limited patients after meniscal root repair. This technical note described the arthroscopic direct meniscal extrusion reduction as surgical tips to reduce persistent meniscal extrusion in posterior meniscal root repair.

The risk of symptomatic knee osteoarthritis after arthroscopic meniscus repair vs partial meniscectomy vs the general population

OBJECTIVE

To compare consultation rate for knee osteoarthritis (OA) after meniscus repair, arthroscopic partial meniscectomy (APM), and in general population, respectively.

METHOD

We identified patients aged 16-45 years having had meniscus surgery due to traumatic meniscus tear in 1998-2010 in southern Sweden by a healthcare register. Patients were followed from surgery until a diagnosis of knee OA, relocation, death, or December 31st, 2015. We studied the consultation rate for knee OA compared to the general population.

RESULTS

We identified 2,487 patients diagnosed with traumatic meniscus tear (mean [SD] age 30.5 [8.6] years); 229 (9.2%) of them had had meniscus repair. The absolute risk of having consulted for knee OA during the study was 17% after APM, 10.0% after meniscus repair, and 2.3% in the general population. Hazard ratio (HR) (95% confidence interval (CI)) for knee OA after repair vs APM was: 0.74 (0.48, 1.15). Excluding cases with OA within 2 years post-surgery, yielded the HR of 0.51 (0.27, 0.96). The consultation rate for knee OA standardized to the general population was then 42 per 10,000 person-years (95% CI 12, 71) in the meniscus repair group, 118 per 10,000 person-years (95% CI 101, 135) after APM, and 20 per 10,000 person-years (95% CI 19.9, 20.1) in the general population.

CONCLUSION

The point estimates suggests about 25-50% lower risk of consultation for knee OA after meniscus repair as compared to APM. However, the consultation rate for knee OA after repair was still at least two times higher as compared to the general population.

Knee internal contact force in a varus malaligned phenotype in knee osteoarthritis (KOA)

PURPOSE

Multiple phenotypes characterized by different disease mechanisms have been hypothesized to explain the large variability in the knee osteoarthritis (KOA) population. The purpose of this study was: to estimate and compare the medial and lateral knee compression forces (CF) during gait of three subgroups of KOA subjects characterized by different alignment and cartilage disruption patterns.

METHODS

A secondary data analysis was conducted on a sample of 39 KOA subjects and 18 controls (C). The patients were classified in the different groups according to the following criteria: Varus medial disease (VMD) (12): varus alignment and predominant medial cartilage degeneration Varus generalized disease (VGD) (17): varus alignment and cartilage degeneration that extends to the lateral compartment. Neutral alignment (NA) (10): neutral alignment. The total, medial and lateral CF corrected for body weight were estimated using an inverse dynamics model (AnyBody Modeling System, AnyBody Technology) during stance.

RESULTS

The impulse of the medial compressive force (MCF) (overall effect of the CF over the stance) was significantly higher (P < 0.01) in the VMD compared to all the other groups. Peak MCF was higher in the VMD compared to all the other groups, but the difference reached significance only when compared to the VGD group (P < 0.05). The results of the regression analysis showed a significant relationship in the VMD group between alignment and impulse of the MCF (R² = 0.62; P < 0.01). This relationship disappears in the other groups.

CONCLUSIONS

These findings suggest the existence of a phenotype characterized by increased MCF.