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

Development of a mind body program for obese knee osteoarthritis patients with comorbid depression

Knee osteoarthritis (OA) is the most common joint disorder in the U.S. and a leading cause of disability. Depression and obesity are highly comorbid among knee OA patients, and the combination of obesity and depression is associated with decreased physical activity, higher pain and disability, and more rapid cartilage degradation. Depression, obesity and OA exacerbate one another and share a common pathophysiology involving systemic inflammation and pro-inflammatory cytokines, reflecting a complex mind-body interaction. Current treatments for knee OA offer little to no benefit over placebo, and do not emphasize mind-body practices or physical activity to target the underlying pathophysiology. Mind-body interventions to lessen depressive symptoms and increase physical activity offer the ability to target biological, mechanical and psychological mechanisms of OA progression. Our long-term goals are to evaluate the mechanisms by which the Relaxation Response Resiliency Program (3RP) delivered via secure telehealth, and adapted for patients with depression, obesity and knee OA (GetActive-OA) promotes increases in physical activity and improved knee health. We hypothesize that the synergistic interaction between mindfulness, adaptive thinking, positive psychology and healthy living skills of the GetActive-OA will slow the progression of symptomatic knee OA by reducing pro-inflammatory cytokine expression and promoting optimal mechanical loading of the cartilage. Here we present the protocol for a mixed methods study that will adapt the 3RP for the needs of knee OA patients with depression and obesity with a focus on increasing physical activity (GetActive-OA), and iteratively maximize the feasibility, credibility and acceptability of the programs and research procedures.

Numerical Investigation of the Effects of Bucket Handle Tears and Subtotal Medial Meniscectomies on the Biomechanical Response of Human Knee Joints

Understanding the complex biomechanical behaviour of the injured and meniscectomised knee joints is of utmost significance in various clinical circumstances. The objective of this study is to investigate the effects of bucket handle tears in the medial meniscus and subtotal medial meniscectomies on the biomechanical response of the knee joints belonging to multiple subjects. The three-dimensional (3D) finite element models of human knee joints including bones, cartilages, menisci, ligaments and tendons are developed from magnetic resonance images (MRI) of multiple healthy subjects. The knee joints are subjected to an axial compressive force, which corresponds to the force of the gait cycle for the full extension position of the knee joint. Three different conditions are compared: intact knee joints, knee joints with bucket handle tears in the medial meniscus and knee joints after subtotal meniscectomies. The bucket handle tear causes a considerable rise in the maximum principal stress at its tip compared to that at the same location in the intact meniscus. This would cause the total rupture of the meniscus resulting in cartilage damage. Subtotal meniscectomy causes a considerable reduction in the contact area along with a substantial increase in the contact pressure and maximum compressive stress in the cartilages in comparison with that in the intact knee. This could give rise to severe degenerative changes in the cartilage. The results of this study could help surgeons in making clinical decisions when managing patients with meniscal injuries.

Knee Injury and Osteoarthritis Outcome Score (KOOS) Responder Criteria and Minimal Detectable Change 3-12 Years Following a Youth Sport-Related Knee Injury

The applicability of thresholds that constitute an acceptable score or meaningful change on the Knee injury and Osteoarthritis Outcome Score (KOOS) in cohorts ≥ 5 years following knee injury is not well understood. The primary objective of this study was to evaluate the association between intra-articular knee injury type and two different KOOS pain thresholds (patient acceptable symptom state (PASS) and Englund symptomatic knee criteria) in the Alberta Youth Prevention of Osteoarthritis (PrE-OA) cohort, which includes participants 3–12 years following a youth sport-related knee injury and uninjured controls with similar age, sex and sport characteristics. Analyses accounted for sex, time since injury and the interaction between time since injury and injury type. Secondary objectives were to report proportions meeting thresholds for KOOS outcomes and minimal detectable change (MDC) from published test–retest reliability data, over a 1–4-year follow-up. Two hundred and fifty-three (253) participants (124 injured, 129 controls) were included in analyses, of which 153 (77 injured, 76 controls) had follow-up data. Similar odds were observed for presence of pain (below PASS threshold) in participants with anterior cruciate ligament (ACL)/meniscus injury (odds ratio (OR) 4.2 (97.5% confidence interval (CI): 1.8, 9.9)) and other knee injuries (OR 4.9 (97.5% CI: 1.2, 21.0)), while there were higher odds for presence of Englund “symptomatic knee” criteria in participants with ACL/meniscus injury (OR 13.6 (97.5% CI: 2.9, 63.4)) than other knee injuries (OR 7.3 (97.5% CI: 0.8, 63.7)) compared to controls. After a median 23.4 (8 to 42) month follow-up, 35% of previously injured participants had at least one KOOS sub-scale score that worsened by more than the MDC published threshold. Despite limited research, this study shows that individuals with youth sport knee injuries other than ACL or meniscus injury may also experience significant pain and symptoms 3–12 years following injury. Replication and further follow-up are needed to identify a possible clinical trajectory towards osteoarthritis.

NF-κB-mediated effects on behavior and cartilage pathology in a non-invasive loading model of post-traumatic osteoarthritis

OBJECTIVE

This study aimed to examine the temporal activation of NF-κB and its relationship to the development of pain-related sensitivity and behavioral changes in a non-invasive murine knee loading model of PTOA.

METHOD

Following knee injury NF-κB activity was assessed longitudinally via in vivo imaging in FVB. Cg-Tg (HIV-EGFP,luc)8Tsb/J mice. Measures of pain-related sensitivity and behavior were also assessed longitudinally for 16 weeks. Additionally, we antagonized NF-κB signaling via intra-articular delivery of an IκB kinase two antagonist to understand how local NF-κB inhibition might alter disease progression.

RESULTS

Following joint injury NF-κB signaling within the knee joint was transiently increased and peaked on day 3 with an estimated 1.35 p/s/cm2/sr (95% CI 0.913.1.792 p/s/cm2/sr) fold increase in signaling when compared to control joints. Furthermore, injury resulted in the long-term development of hindpaw allodynia. Hyperalgesia withdrawal thresholds were reduced at injured knee joints, with the largest reduction occurring 2 days following injury (estimate of between group difference 129.1 g with 95% CI 60.9,197.4 g), static weight bearing on injured limbs was also reduced. Local delivery of an NF-κB inhibitor following joint injury reduced chondrocyte death and influenced the development of pain-related sensitivity but did not reduce long-term cartilage degeneration.

CONCLUSION

These findings underscore the development of behavioral changes in this non-invasive loading model of PTOA and their relationships to NF-κB activation and pathology. They also highlight the potential chondroprotective effects of NF-κB inhibition shortly following joint injury despite limitations in preventing the long-term development of joint degeneration in this model of PTOA.

An algorithmic approach to reducing unexplained pain disparities in underserved populations

Underserved populations experience higher levels of pain. These disparities persist even after controlling for the objective severity of diseases like osteoarthritis, as graded by human physicians using medical images, raising the possibility that underserved patients' pain stems from factors external to the knee, such as stress. Here we use a deep learning approach to measure the severity of osteoarthritis, by using knee X-rays to predict patients' experienced pain. We show that this approach dramatically reduces unexplained racial disparities in pain. Relative to standard measures of severity graded by radiologists, which accounted for only 9% (95% confidence interval (CI), 3-16%) of racial disparities in pain, algorithmic predictions accounted for 43% of disparities, or 4.7× more (95% CI, 3.2-11.8×), with similar results for lower-income and less-educated patients. This suggests that much of underserved patients' pain stems from factors within the knee not reflected in standard radiographic measures of severity. We show that the algorithm's ability to reduce unexplained disparities is rooted in the racial and socioeconomic diversity of the training set. Because algorithmic severity measures better capture underserved patients' pain, and severity measures influence treatment decisions, algorithmic predictions could potentially redress disparities in access to treatments like arthroplasty.

Exercise-therapy and education for individuals one year after anterior cruciate ligament reconstruction: a pilot randomised controlled trial

BACKGROUND

Guided rehabilitation beyond 6-months is rare following anterior cruciate ligament reconstruction (ACLR), despite high prevalence of unacceptable symptoms and quality of life (QoL). Our primary aim was to determine the feasibility of a randomised controlled trial (RCT) evaluating a physiotherapist-guided intervention for individuals 1-year post-ACLR with persistent symptoms. Our secondary aim was to determine if a worthwhile treatment effect could be observed for the lower-limb focussed intervention (compared to the trunk-focussed intervention), for improvement in knee-related QoL, symptoms, and function.

DESIGN

Participant- and assessor-blinded, pilot feasibility RCT.

METHODS

Participant eligibility criteria: i) 12-15 months post-ACLR; ii) < 87.5/100 on the Knee injury and Osteoarthritis Outcome Score (KOOS) QoL subscale; and either a one-leg rise test < 22 repetitions, single-hop < 90% limb symmetry; or Anterior Knee Pain Scale < 87/100. Participants were randomised to lower-limb or trunk-focussed focussed exercise and education. Both interventions involved 8 face-to-face physiotherapy sessions over 16-weeks. Feasibility was assessed by eligibility rate (> 1 in 3 screened), recruitment rate (> 4 participants/month), retention (< 20% drop-out), physiotherapy attendance and unsupervised exercise adherence (> 80%). Between-group differences for knee-related QoL (KOOS-QoL, ACL-QoL), symptoms (KOOS-Pain, KOOS-Symptoms), and function (KOOS-Sport, functional performance tests) were used to verify that the worthwhile effect (greater than the minimal detectable change for each measure) was contained within the 95% confidence interval.

RESULTS

47% of those screened were eligible, and 27 participants (3 participants/month; 48% men, 34±12 years) were randomised. Two did not commence treatment, and two were lost to follow-up (16% drop-out). Physiotherapy attendance was > 80% for both groups but reported adherence to unsupervised exercise was low (< 55%). Both interventions had potentially worthwhile effects for KOOS-QoL and ACL-QoL, while the lower-limb focussed intervention had potentially greater effects for KOOS-Sport, KOOS-Pain, and functional performance.

CONCLUSIONS

A larger-scale RCT is warranted. All feasibility criteria were met, or reasonable recommendations could be made to achieve the criteria in future trials. Strategies to increase recruitment rate and exercise adherence are required. The potential worthwhile effects for knee-related QoL, symptoms, and function indicates a fully-powered RCT may detect a clinically meaningful effect.

TRIAL REGISTRATION

Prospectively registered ( ACTRN12616000564459 ).

Polyurethane scaffold implants for partial meniscus lesions: delayed intervention leads to an inferior outcome

PURPOSE

The purpose of this study was to assess the clinical outcomes of the implantation of an aliphatic polyurethane scaffold for the treatment of partial loss of meniscal tissue at a mean follow-up of 36 months.

METHODS

A retrospective review on prospectively collected data was performed on patients who underwent implantation of an aliphatic polyurethane-based synthetic meniscal scaffold. Patients were evaluated for demographics data, lesion and implant characteristics (sizing, type and number of meniscal sutures), previous and combined surgeries and complications. Clinical parameters were rated using NRS, IKDC subjective, Lysholm, KOOS, and Tegner activity score, both preoperatively and at final follow-up.

RESULTS

Sixty-seven patients were evaluated at a mean follow-up of 36 months (48 M and 19 F; mean age 40.8 ± 10.6 years; mean BMI 25.4 ± 4.3). The scaffold was implanted on the medial side in 54 cases, and on the lateral one in 13. Forty-seven patients had undergone previous surgical treatment at the same knee and 45 required combined surgical procedures. All evaluated scores improved significantly from the baseline. Among possible prognostic factors, a delayed scaffold implantation had lower post-operative clinical scores: IKDC subjective (P = 0.049), KOOS Sport (P = 0.044), KOOS total (p = 0.011), and Tegner (P = 0.03) scores at follow-up.

CONCLUSIONS

The polyurethane meniscal scaffold implantation led to a significant clinical benefit in a large number of patients. A delayed intervention correlated with worse results.

LEVEL OF EVIDENCE

IV.

Synovial mesenchymal stem cells promote the meniscus repair in a novel pig meniscus injury model

Stem cell therapy has potential for the treatment of degenerative meniscus injuries; however, an optimal animal model has not been established. Basic and clinical research show that synovial mesenchymal stem cells (MSCs) promote meniscus repair. The purposes of this study were to create a novel meniscus injury model in microminipigs and to investigate the effectiveness of synovial MSCs on meniscus healing in this model. The posterior portion of the medial meniscus in microminipigs was punctuated 200 times with a 23G needle. Allogenic synovial MSC suspension was placed on the injury site for 10 min for transplantation. The meniscus was evaluated histologically and via sagittal magnetic resonance imaging (MRI), radial MRI reconstructed in three dimensional, and T2 mapping at 1 and 8 weeks. Proteoglycan content stained with safranin-o disappeared 1 week after treatment in both the MSC and control groups but increased at 8 weeks only in the MSC group. Histological scores at 8 weeks were significantly higher in the MSC group than in the control group (n = 6). At 8 weeks, the T2 values of the MSC group were significantly closer to those of a normal meniscus than were those of the control group. High signal intensity areas of the MRIs and positive areas stained with picrosirius red coincided with meniscal lesions. In conclusion, we created a novel meniscus injury model in microminipigs. Evaluation via histology, MRIs, and polarized microscopy showed that transplantation of synovial MSCs improved meniscus healing.

Comparison of meniscal allograft transplantation techniques using a preclinical canine model

Meniscal allograft transplantation (MAT) can be a safe, effective treatment for meniscal deficiency resulting in knee dysfunction, leading to osteoarthritis (OA) without proper treatment with 5-year functional success rates (75%-90%). While different grafts and techniques have generally proven safe and effective, complications include shrinkage, extrusion, progression of joint pathology, and failure. The objective of this study was to assess the functional outcomes after MAT using three different clinically-relevant methods in a preclinical canine model. The study was designed to test the hypothesis that fresh meniscal-osteochondral allograft transplantation would be associated with significantly better function and joint health compared with fresh-viable or fresh-frozen meniscus-only allograft transplantations. Three months after meniscal release to induce meniscus-deficient medial compartment disease, research hounds (n = 12) underwent MAT using meniscus allografts harvested from matched dogs. Three MAT conditions (n = 4 each) were compared: frozen meniscus-fresh-frozen meniscal allograft with menisco-capsular suture repair; fresh meniscus-fresh viable meniscal allograft (Missouri Osteochondral Preservation System (MOPS)-preservation for 30 days) with menisco-tibial ligament repair; fresh menisco-tibial-fresh, viable meniscal-tibial-osteochondral allografts (MOPS-preservation for 30 days) with menisco-tibial ligament preservation and autogenous bone marrow aspirate concentrate on OCA bone. Assessment was performed up to 6 months after MAT. Pain, comfortable range of motion, imaging, and arthroscopic scores as well histological and cell viability findings were superior (P < .05) for the fresh menisco-tibial group compared with the two other groups. Novel meniscal preservation and implantation techniques with fresh, MOPS-preserved, viable meniscal-osteochondral allografts with menisco-tibial ligament preservation appears to be safe and effective for restoring knee function and joint health in this preclinical model. This has the potential to significantly improve outcomes after MAT.

Low knee-related quality of life and persistent physical asymmetries in participants up to 10 years post-ACL reconstruction - A cross-sectional study

OBJECTIVE

To compare self-report and functional outcomes between participants with anterior cruciate ligament reconstruction (ACLR) with age and activity matched controls.

DESIGN

Cross-sectional study.

SETTING

University laboratory-based study.

PARTICIPANTS

Twenty-five participants (30.8 ± 9.7 years; 13 women), two to ten years post anterior cruciate ligament reconstruction; 24 controls (31.0 ± 10 years, 13 women).

MAIN OUTCOME MEASURES

Knee Osteoarthritis and Injury Outcome Score (KOOS), Tegner, Marx Activity and Fear of Re-injury scales, and SF-12; isokinetic quadriceps and hamstring peak torque and single-leg hop distance.

RESULTS

There were no between-groups differences for the Tegner and the Marx Activity Scales. The ACLR group had lower KOOS dimensions (p < 0.001), SF-12 Physical Component Scores (p = 0.008), and higher Fear of Reinjury Scores (<0.001) than the controls. No significant differences were found for physical performance measures between the ACLR and the control groups. Significant between-side differences for the ACLR group were evident for concentric quadriceps (p < 0.001) and concentric hamstring peak torque (p = 0.002), and hop distance (p < 0.001).

CONCLUSION

Knee-specific symptoms and function, activity and quality of life were lower, and fear of re-injury was higher for participants with ACLR than controls. Side-to-side thigh muscle strength and hop distance deficits were evident for the ACLR group.

Initial clinical outcomes comparing frozen versus fresh meniscus allograft transplants

BACKGROUND

To evaluate initial clinical outcomes using fresh meniscal allografts with high cell viability at transplantation time and meniscotibial ligament (MTL) reconstruction (Fresh) in comparison to standard fresh-frozen (Frozen) meniscus allograft transplantation (MAT).

METHODS

Patients treated for medial and/or lateral meniscal deficiency using either Fresh or Frozen MAT with minimum of 1-year follow-up were identified from a prospective registry. Patient demographics, prior surgeries, MAT surgery data, complications, revisions, and failures were documented. Functional outcome scores were collected preoperatively, and 6 months and yearly after surgery and radiographic joint space measurements were performed. Treatment cohorts were compared for statistically significant (P < 0.005) differences using t-Tests and Fisher's exact tests.

RESULTS

Twenty-seven patients (14 Fresh, 13 Frozen) met inclusion criteria and showed comparable characteristics. For Fresh MAT + MTL, 10 medial, two lateral, and two medial + lateral MAT were performed. For Frozen MAT, nine medial, and four lateral MAT were performed. There was significantly more improvement in the Fresh cohort compared to the Frozen cohort for VAS pain (P = 0.014), PROMIS Physical Function (P = 0.036) and Single Assessment Numeric Evaluation (P = 0.033) from preoperatively to 2 years postoperatively. Tegner Activity Scale and PROMIS Mobility score showed no significant differences. The International Knee Documentation Committee score revealed a clinically meaningful change for the Fresh group. Radiographic measurements showed no significant differences between groups. There were two Fresh MAT + MTL revisions and one conversion to TKA in each cohort.

CONCLUSIONS

Fresh MAT + MTL is safe and associated with potential advantages with respect to initial pain relief and function compared to standard frozen MAT.

Natural history of new horizontal meniscal tears in individuals at risk for and with mild to moderate osteoarthritis: data from osteoarthritis initiative

OBJECTIVES

To study the natural history of new horizontal meniscal tears and their association with progression of cartilage degeneration in individuals at risk for or with mild to moderate knee osteoarthritis over 4 years.

METHODS

Individuals who developed a new meniscal tear in the right knee over 2 years were selected from the Osteoarthritis Initiative 3T MRI studies. Knee structural changes were analyzed at the time of tear appearance (baseline), and after 4 years using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). Meniscal tears were classified as either horizontal tears or non-horizontal tears. Individuals without a meniscal tear were 1:3 frequency matched according to BMI, gender, race, and age and served as the control group. Linear regression analysis was used to compare cross-sectional and longitudinal changes in cartilage WORMS scores.

RESULTS

Forty-one subjects developed horizontal tears, including one indiviudal who developed a tear in both menisci, and 34 developed non-horizonal tears. We found that (29/41 (70.7%)) of horizontal and (20/34 (58.8%)) of non-horizonatal tears were stable during follow-up (p = 0.281). Although knees with an incident tear had higher than controls WORMS MAX total knee scores at baseline (coef. = 0.47, p = 0.044, 95% CI = 0.01 to 0.93), there were no significant differences between the horizontal subgroup and knees without tears in overall cartilage scores at baseline and in progression over 4 years of follow-up.

CONCLUSIONS

New horizontal meniscal tears tended to be stable over 4 years and presented no significant differences in progression of cartilage degeneration when compared with knees without tears.

KEY POINTS

• Most of horizonal meniscal tears were stable over 4 years. • There were no statistically significant differences in overall progression of cartilage degenerative changes between knees with horizonal meniscal tears and control knees without tears • Horizontal tears most often occurred at the posterior horn of the medial meniscus and at the body of the lateral meniscus.

Autologous Adipose-Derived Stem Cell Sheet Has Meniscus Regeneration-Promoting Effects in a Rabbit Model

PURPOSE

This study investigated meniscal regeneration-promoting effects of adipose-derived stem cell (ADSC) sheets in a rabbit meniscal defect models.

METHODS

ADSCs were extracted from the interscapular fat pad adipose tissue of 42 mature female Japanese white rabbits. Once cells reached confluence at the third passage, the culture medium was supplemented with ascorbic acid. Within a week, the cells in culture formed removable sheets, which were used as ADSC sheets. Cell death (CD) sheets were created by killing ADSCs by freezing to investigate the need for viable ADSCs in ADSC sheets. The anterior half of the medial meniscus from the anterior root to the posterior edge of the medial collateral ligament was removed from both limbs. An autologous ADSC or CD sheet was transplanted to one knee (ADSC sheet or CD sheet group). The contralateral limb was closed without transplantation following meniscal removal (control group). Rabbits were euthanized 4 and 12 weeks after transplantation to harvest the entire medial menisci. The meniscal tissue area, transverse diameter on the inside of the medial collateral ligament, and histologic score were compared between the 3 groups.

RESULTS

The area and transverse diameter of regenerated tissues were larger in the ADSC sheet group than in the control group at 4 and 12 weeks. Further, the histologic score in the ADSC sheet group (8) was significantly greater than that in the control group (4.5) at 4 weeks (P = .02) and greater than that in the CD sheet group (9) (ADSC = 12.5, P = .009) and control group (6) (ADSC = 12.5, P = .0003) at 12 weeks.

CONCLUSIONS

Transplantation of the ADSC sheet into the meniscal defect increased the volume and improved the histologic score of the regenerated meniscal tissue. ADSC sheets may have meniscal regeneration-promoting effects in a rabbit model with meniscal defects.

CLINICAL RELEVANCE

ADSC sheets do not require a scaffold for implantation in the rabbit model, and this evidence suggests that some tissue regeneration occurs at the site of a surgically created meniscal defect.

Surgical treatment of complex meniscus tear and disease: state of the art

The meniscus is important for load distribution, shock absorption and stability of the knee joint. Meniscus injury or meniscectomy results in decreased function of the meniscus and increased risk of knee osteoarthritis. To preserve the meniscal functions, meniscal repair should be considered as the first option for meniscus injury. Although reoperation rates are higher after meniscal repair compared with arthroscopic partial meniscectomy, long-term follow-up of meniscal repair demonstrated better clinical outcomes and less severe degenerative changes of osteoarthritis compared with partial meniscectomy. In the past, the indication of a meniscal repair was limited both because of technical reasons and due to the localised vascularity of the meniscus. Meanwhile, it spreads today as the development of the concept to preserve the meniscus and the improvement of meniscal repair techniques. Longitudinal vertical tears in the peripheral third are considered the 'gold standard' indication in terms of meniscus healing. Techniques for meniscal repair include 'inside-out', 'outside-in' and 'all-inside' strategies. Surgical decision-making depends on the type, size and location of the meniscus injury. Meniscal root tears substantially affect meniscal hoop function and accelerate cartilage degeneration; therefore, meniscus root repair is necessary to prevent the progression of osteoarthritis change. For symptomatic meniscus defects after meniscectomy, transplantation of allograft or collagen meniscus implant may be indicated, and acceptable clinical results have been obtained. Recently, meniscus extrusion has attracted attention due to increased interest in early osteoarthritis. The centralisation techniques have been proposed to reduce the meniscus extrusion by suturing the meniscus-capsule complex to the edge of the tibial plateau. Long-term clinical outcomes of this procedure may change the strategy of treating meniscus extrusion. When malalignment of the lower leg is accompanied with meniscus pathologies, knee osteotomies are a reasonable option to protect the repaired meniscus by unloading the pathological compartment. Advancements in biological augmentation such as bone marrow stimulation, fibrin clot, platelet-rich plasma, stem cell therapy and scaffolds have also expanded the indications for meniscus surgery. In summary, improved repair techniques and biological augmentation have made meniscus repair more appealing to treat that had previously been considered irreparable. However, further research would be necessary to validate the efficacy of these specialised technique.

Is Self-Reported Knee Stability Associated With Symptoms, Function, and Quality of Life in People With Knee Osteoarthritis After Anterior Cruciate Ligament Reconstruction?

OBJECTIVE

This study aimed to investigate the association of self-reported knee stability with symptoms, function, and quality of life in individuals with knee osteoarthritis after anterior cruciate ligament reconstruction (ACLR).

SETTING

Cross-sectional.

PARTICIPANTS

Twenty-eight individuals with knee osteoarthritis, 5 to 12 years after ACLR.

MAIN OUTCOME MEASURES

Self-reported knee stability was assessed using visual analogue scales (VAS) during hop for distance (HD), side-to-side hop (SSH), and one-leg rise (OLR). Symptoms [Knee Injury and Osteoarthritis Outcome Score (KOOS) pain, Anterior Knee Pain Scale (AKPS), and International Knee Documentation Committee form], self-reported function (KOOS-sport/rec), performance-based function (hopping and OLR), and quality of life (KOOS-QOL) were assessed. K-means clustering categorized individuals into low (n = 8) and high self-reported knee stability (n = 20) groups based on participants' VAS scores during functional tasks.

RESULTS

The low self-reported knee stability group had worse knee symptoms than the high self-reported knee stability group [KOOS-pain: mean difference -17 (95% confidence interval, -28 to -5); AKPS: -10 (-20 to -1)], and worse self-reported function [KOOS-sport/rec: -33 (-48 to -18)] and performance-based function [HD: -28 (-53 to -3); SSH: -10 (-20 to -1), OLR: -18 (-32 to -50)].

CONCLUSION

Low self-reported stability is associated with worse symptoms, and worse self-reported and performance-based function. Further research is required to determine the causation relation of self-reported knee stability to knee symptoms and function in individuals with knee osteoarthritis after ACLR.

Molecular biology of meniscus pathology: Lessons learned from translational studies and mouse models

Injury to any individual structure in the knee interrupts the overall function of the joint and initiates a cascade of biological and biomechanical changes whose endpoint is often osteoarthritis (OA). The knee meniscus is an integral component of knee biomechanics and may also contribute to the biological homeostasis of the joint. Meniscus injury altering knee function is associated with a high risk of OA progression, and may also be involved in the initiation of OA. As the relationship between meniscus injury and OA is very complex; despite the availability of transcript level data on human meniscus injury and meniscus mediated OA, mechanistic studies are lacking, and available human data are difficult to validate in the absence of patient-matched noninjured control tissues. As similarities exist between human and mouse knee joint structure and function, investigators have begun to use cutting-edge genetic and genomic tools to examine the usefulness of the mouse as a model to study the intricate relationship between meniscus injury and OA. In this review, we use evidence from human meniscus research to identify critical barriers hampering our understanding of meniscus injury induced OA and discuss strategies to overcome these barriers, including those that can be examined in a mouse model of injury-mediated OA.

Arthroscopic partial meniscectomy for a degenerative meniscus tear: a 5 year follow-up of the placebo-surgery controlled FIDELITY (Finnish Degenerative Meniscus Lesion Study) trial

Objectives

To assess the long-term effects of arthroscopic partial meniscectomy (APM) on the development of radiographic knee osteoarthritis, and on knee symptoms and function, at 5 years follow-up.

Design

Multicentre, randomised, participant- and outcome assessor-blinded, placebo-surgery controlled trial.

Setting

Orthopaedic departments in five public hospitals in Finland.

Participants

146 adults, mean age 52 years (range 35–65 years), with knee symptoms consistent with degenerative medial meniscus tear verified by MRI scan and arthroscopically, and no clinical signs of knee osteoarthritis were randomised.

Interventions

APM or placebo surgery (diagnostic knee arthroscopy).

Main outcome measures

We used two indices of radiographic knee osteoarthritis (increase in Kellgren and Lawrence grade ≥1, and increase in Osteoarthritis Research Society International (OARSI) atlas radiographic joint space narrowing and osteophyte sum score, respectively), and three validated patient-relevant measures of knee symptoms and function (Western Ontario Meniscal Evaluation Tool (WOMET), Lysholm, and knee pain after exercise using a numerical rating scale).

Results

There was a consistent, slightly greater risk for progression of radiographic knee osteoarthritis in the APM group as compared with the placebo surgery group (adjusted absolute risk difference in increase in Kellgren-Lawrence grade ≥1 of 13%, 95% CI −2% to 28%; adjusted absolute mean difference in OARSI sum score 0.7, 95% CI 0.1 to 1.3). There were no relevant between-group differences in the three patient-reported outcomes: adjusted absolute mean differences (APM vs placebo surgery), −1.7 (95% CI −7.7 to 4.3) in WOMET, −2.1 (95% CI −6.8 to 2.6) in Lysholm knee score, and −0.04 (95% CI −0.81 to 0.72) in knee pain after exercise, respectively. The corresponding adjusted absolute risk difference in the presence of mechanical symptoms was 18% (95% CI 5% to 31%); there were more symptoms reported in the APM group. All other secondary outcomes comparisons were similar.

Conclusions

APM was associated with a slightly increased risk of developing radiographic knee osteoarthritis and no concomitant benefit in patient-relevant outcomes, at 5 years after surgery.

Trial registration

ClinicalTrials.gov (NCT01052233 and NCT00549172).

Gene Expression in Meniscal Tears at the Time of Arthroscopic Partial Meniscectomy Predicts the Progression of Osteoarthritis Within 6 Years of Surgery

Background:

While knees with meniscal tears are associated with a heightened risk of developing osteoarthritis (OA), it is difficult to predict which patients are at the greatest risk for OA. Gene signatures in menisci that are resected during arthroscopic partial meniscectomy (APM) may provide insight into the risk of OA progression.

Hypothesis:

Meniscal gene signatures at the time of APM will predict radiographic OA progression.

Study Design:

Case series; Level of evidence, 4.

Methods:

Meniscal fragments were collected from 38 patients without OA during clinically indicated APM of the medial meniscus. The expression of 28 candidate genes with known roles in cartilage homeostasis, OA, extracellular matrix degradation, and obesity was assessed by quantitative real-time polymerase chain reaction. Weightbearing radiographs obtained before surgery and at final follow-up were graded by a musculoskeletal radiologist using the Kellgren-Lawrence classification of OA. The association of meniscal gene expression at baseline with the progression of radiographic OA was determined.

Results:

Gene expression and baseline and follow-up radiographic data were available from 31 patients (81.6%) at a mean follow-up of 6.2 ± 1.3 years. Patients without OA progression had significantly higher expression of 7 genes: MMP9 (5.1-fold; P = .002), IL8 (2.9-fold; P = .016), CCL3 (3.7-fold; P = .032), CCL3L1 (4.5-fold; P = .008), CXCL6 (6.2-fold; P = .010), LEP (5.2-fold; P = .004), and RETN (46-fold; P = .008).

Conclusion:

Gene expression in the meniscus at the time of APM may be associated with the risk for progression of OA after surgery. Elevated expression of the aforementioned genes may reflect a chondroprotective response. Stratifying the risk for OA progression after APM could facilitate targeted interventions to delay or prevent the development of OA. Further studies in a larger cohort with an extended follow-up, and inclusion of additional genes, are warranted to better characterize this association.

Traumatic Meniscal Tears Are Associated With Meniscal Degeneration

BACKGROUND

Meniscal tears are traditionally classified into traumatic versus degenerative tears. Although this classification plays a major role in clinical decision making, no consensus exists on the exact definition of a traumatic or degenerative tear, and the histopathological basis for this classification is unclear.

PURPOSE

To assess the histological degree of meniscal degeneration in patients with a traumatic meniscal tear, as compared with intact meniscal tissue and osteoarthritic meniscal tissue.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Traumatically torn meniscal tissue was collected during arthroscopic partial meniscectomy. As a control group, intact meniscal tissue was used from transfemoral amputations or direct postmortem dissections. Meniscal tissue from osteoarthritic knees was obtained during total knee replacement surgery. Meniscal tissue was processed, stained, and histologically analyzed with the Pauli scoring system (range, 0-18), comprising the subdomains surface integrity, cellularity, collagen organization, and matrix staining. Scoring was performed by 2 independent observers, blinded to condition, region, and patient data of the meniscus.

RESULTS

The traumatic meniscal tear group contained 43 patients (34 men; median age, 29 years; median body mass index [BMI], 24 kg/m²); the intact meniscal tissue group, 8 patients (3 men; median age, 58 years; median BMI, 30 kg/m²); and the osteoarthritic group, 14 patients (4 men; median age, 66 years; median BMI, 28 kg/m²). After adjustment for sex, age, and BMI, patients with a traumatic meniscal tear had a significantly higher histological score than patients with intact meniscal tissue (2.7-point difference; P = .035). Histological score between the traumatic and osteoarthritic groups was not different.

CONCLUSION

Traumatically torn menisci possess a higher degree of degeneration than intact menisci. Our results suggest that patients with a traumatic meniscal tear may already have had a certain degree of meniscal degeneration. These findings potentially challenge the classic view of traumatic versus degenerative meniscal tears.

CLINICAL RELEVANCE

Our findings provide a better understanding of the tissue condition of a torn meniscus. This knowledge may help clinicians decide on choice of treatment and may lead to new perspectives to prevent knee osteoarthritis in patients with a torn meniscus.

Radiographic and Symptomatic Knee Osteoarthritis 32 to 37 Years After Acute Anterior Cruciate Ligament Rupture

BACKGROUND

The long-term prevalence of knee osteoarthritis (OA) after anterior cruciate ligament (ACL) injury is unknown, especially in patients without a history of ACL surgery.

PURPOSE

To (1) describe the prevalence of radiographic OA, symptomatic OA, and knee replacement surgery 32 to 37 years after acute ACL injury and to (2) compare the prevalence of radiographic OA, symptomatic OA, and knee symptoms between patients allocated to early ACL surgery or no ACL surgery and patients who crossed over to ACL surgery.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Participants aged 15 to 40 years at the time of ACL injury were allocated to surgical (augmented or nonaugmented ACL repair) or nonsurgical ACL treatment within 14 days of injury. At 32 to 37 years after the initial injury, 153 participants were followed up with plain weightbearing radiographs and completed 4 subscales from the Knee injury and Osteoarthritis Outcome Score (KOOS). Radiographic OA was defined as Kellgren and Lawrence grade 2 or higher. Symptomatic OA was defined as radiographic OA plus knee symptoms measured with the KOOS.

RESULTS

Participants allocated to ACL surgery (n = 64) underwent surgery at a mean ± SD of 5 ± 4 days (range, 0-11 days) after injury. Of the 89 participants allocated to no ACL surgery, 53 remained nonsurgically treated, 27 had ACL surgery within 2 years, and 9 had ACL surgery between 3 and 21 years after injury. In the total sample, 95 participants (62%) had radiographic tibiofemoral OA, including 11 (7%) who had knee replacement. The prevalence of radiographic tibiofemoral OA was lower in the group allocated to ACL surgery compared with the group who never had ACL surgery (50% vs 75%; P = .005). The prevalence of symptomatic OA (50% in the total sample) and patellofemoral radiographic OA (35% in the total sample) was similar between groups.

CONCLUSION

Patients allocated to early ACL surgery, performed a mean 5 days after injury, had a lower prevalence of tibiofemoral radiographic OA at 32 to 37 years after injury compared with patients who never had ACL surgery. The prevalences of symptomatic OA, radiographic patellofemoral OA, and knee symptoms were similar irrespective of ACL treatment. Overall, the prevalence of OA after ACL injury was high.

REGISTRATION

NCT03182647 (ClinicalTrials.gov identifier).

Surgical Treatment of Meniscal Extrusion: A Biomechanical Study on the Role of the Medial Meniscotibial Ligaments With Early Clinical Validation

Background

Meniscal extrusion refers to meniscal displacement out of the joint space and over the tibial margin, altering knee mechanics and increasing the risk of osteoarthritis. The meniscotibial ligaments have been shown to have an important role in meniscal stability. However, it remains unclear whether an isolated lesion of the medial meniscotibial ligaments will result in meniscal extrusion and whether repairing the detached ligament will reduce extrusion.

Hypothesis

A lesion of the medial meniscotibial ligament will result in meniscal extrusion, and repairing the joint capsule will eliminate the extrusion by returning the meniscus back to its original position.

Study Design

Controlled laboratory study.

Methods

Fresh-frozen human cadaveric knees (N = 6) were used for biomechanical testing. The test protocol involved 100 flexion-extension cycles. In full extension, meniscal extrusion was measured using ultrasound, in both an otherwise unloaded state and while subjected to a 10-N·m varus load. Each knee was tested in its native condition (baseline), after creating a detachment of the medial meniscotibial ligament, and finally with the joint capsule repaired using 3 knotless SutureTak anchors. We also performed a retrospective review of 15 patients who underwent meniscotibial ligament repair with a minimal follow-up of 5 weeks (mean, 14 weeks; range, 5-35 weeks).

Results

During biomechanical testing, the mean absolute meniscal extrusion at baseline was 1.5 ± 0.6 mm. After creation of the meniscotibial ligament lesion, the mean absolute meniscal extrusion was significantly increased (3.4 ± 0.7 mm) (P < .001). After repair, the extrusion was reduced to 2.1 ± 0.4 mm (P < .001). Clinically, a reduction in absolute meniscal extrusion of approximately 48% was reached (1.2 ± 0.6 vs 2.4 ± 0.5 mm preoperatively; P < .001).

Conclusion

This study indicates that the medial meniscotibial ligaments contribute to meniscal stability as lesions cause the meniscus to extrude and that repair of those ligaments can significantly reduce extrusion. Early clinical results using this meniscotibial ligament repair technique support our biomechanical findings, as a significant reduction in meniscal extrusion was achieved.

Clinical Relevance

Our biomechanical findings suggest that repair of medial meniscotibial ligaments reduces meniscal extrusion and clinically may improve meniscal function, with the possible long-term benefit of reducing the risk for osteoarthritis.

Early Magnetic Resonance Imaging-Based Changes in Patients With Meniscal Tear and Osteoarthritis: Eighteen-Month Data From a Randomized Controlled Trial of Arthroscopic Partial Meniscectomy Versus Physical Therapy

OBJECTIVE

The present study was undertaken to evaluate changes in knee magnetic resonance imaging (MRI) findings over the course of 18 months in subjects with osteoarthritic change and meniscal tear treated with arthroscopic partial meniscectomy (APM) or nonoperatively with physical therapy (PT).

METHODS

We used 18-month follow-up data from the Meniscal Tear in Osteoarthritis Research Trial. MRI results were read with reference to the MRI Osteoarthritis Knee Score. We focused on 18-month change in bone marrow lesions (BMLs), cartilage thickness, cartilage surface area, osteophyte size, effusion-synovitis, and Hoffa-synovitis. We used multinomial logistic regression to assess associations between MRI-based changes in each feature and treatment type.

RESULTS

A total of 351 subjects were randomized, and 225 had both baseline and 18-month MRI results. In both treatment groups, patients experienced substantial changes in several MRI-based markers. In 60% of the APM group, versus 33% of the PT group, cartilage surface area damage advanced in ≥2 subregions (adjusted odds ratio 4.2 [95% confidence interval 2.0-9.0). Patients who underwent APM also had greater advancement in scores for osteophytes and effusion-synovitis. We did not find significant associations between treatment type and change in cartilage thickness, BMLs, or Hoffa-synovitis.

CONCLUSION

This cohort of patients with meniscal tear and osteoarthritis showed marked advancement in MRI-based features over 18 months. Patients treated with APM showed more advancement in some features compared to those treated nonoperatively. The clinical relevance of these early findings is unknown and requires further study.

The Difference in Medial Meniscal Extrusion between Non-Weight-Bearing and Weight-Bearing Positions in People with and without Medial Compartment Knee Osteoarthritis

BACKGROUND

Medial meniscal extrusion (MME) has been correlated with medial meniscal injury and progression of medial knee osteoarthritis (OA).

OBJECTIVE

To examine the difference in MME between non-weight-bearing (supine) and weight-bearing (standing) positions in patients with and without medial knee OA. Determine the correlation between body mass index (BMI), Kellgren-Lawrence (KL) grade, Knee Osteoarthritis Outcome Score (KOOS), and MME.

DESIGN

Prospective.

SETTING

Tertiary institution PM&R Department.

PARTICIPANTS

Forty five participants (29 female, 16 male), 24 with healthy knees and 21 with OA.

METHODS OR INTERVENTIONS

A single physician sonographer measured supine and standing MME with ultrasound (US) on each participant. The physician was blinded to all measurements. BMI was recorded on all participants. KL grades and KOOS questionnaires were obtained for the OA group.

MAIN OUTCOME MEASURES

MME in supine and standing positions, change in MME from supine to standing, BMI, KL grade, and KOOS subscale scores.

RESULTS

MME increased .52 mm from supine to standing (P < .001). MME was greater in the OA group in both the supine (P = .002) and standing (P < .001) positions. Increasing BMI was moderately correlated with increasing MME (supine P = .001, standing <.001). Increasing age was correlated with increasing MME (supine P = .012, standing P = .002). Increasing KL grade (from 1 to 4) was correlated with increasing MME (supine P = .015, standing = .006). There was a small-to-moderate correlation between KOOS activities of daily living (ADL) subscale score and change in MME from supine to standing (P = .035). The change in MME from supine to standing positions had a small-to-moderate correlation (P = .035) with KOOS ADL subscale score alone but did not correlate with any of the other KOOS subscale scores or KOOS total scores. Receiver operating characteristic curve analysis suggested a standing MME value of 4.2 mm provides a positive likelihood ratio of 6.02 for knee OA.

CONCLUSIONS

MME is greater in those with OA and with weight-bearing. MME correlates with BMI, age, KL grade, and the KOOS ADL subscale score. Finally, standing MME of 4.2 mm yielded a higher positive likelihood ratio to differentiate between healthy knees and those with medial compartment OA than the previously reported value of 3.0 mm.

Biomechanical effects of manipulating peak vertical ground reaction force throughout gait in individuals 6-12 months after anterior cruciate ligament reconstruction

BACKGROUND

We aimed to determine the effect of cueing an increase or decrease in the vertical ground reaction force impact peak (peak in the first 50% of stance) on vertical ground reaction force, knee flexion angle, internal knee extension moment, and internal knee abduction moment waveforms throughout stance in individuals 6-12 months after an anterior cruciate ligament reconstruction.

METHODS

Twelve individuals completed 3 conditions (High, Low, and Control) where High and Low Conditions cue a 5% body weight increase or decrease, respectively, in the vertical ground reaction force impact peak compared to usual walking. Biomechanics during High and Low Conditions were compared to the Control Condition throughout stance.

FINDINGS

The High Condition resulted in: (a) increased vertical ground reaction forces at each peak and decreased during mid-stance, (b) greater knee excursion (i.e., greater knee flexion angle in early stance and a more extended knee in late stance), (c) greater internal extension moment for the majority of stance, and (d) lesser second internal knee abduction moment peak. The Low Condition resulted in: (a) vertical ground reaction forces decreased during early stance and increased during mid-stance, (b) decreased knee excursion, (c) increased internal extension moment throughout stance, and (d) decreased internal knee abduction moment peaks.

INTERPRETATION

Cueing a 5% body weight increase in vertical ground reaction force impact peak resulted in a more dynamic vertical ground reaction force loading pattern, increased knee excursion, and a greater internal extension moment during stance which may be useful in restoring gait patterns following anterior cruciate ligament reconstruction.

Notch Regulates Fibrocartilage Stem Cell Fate and Is Upregulated in Inflammatory TMJ Arthritis

The Notch pathway is critical for the development of the extracellular matrix in cartilage by regulating both anabolic and catabolic cellular activities. Similarly, Notch signaling plays a biphasic role in adult cartilage health and osteoarthritis by maintaining homeostasis and contributing to degeneration, respectively. The temporomandibular joint (TMJ) is the synovial joint of the craniofacial complex and is subject to injury and osteoarthritis. While Notch has been studied in axial skeletal joints, little is known about the role of Notch in TMJ development and disease. We identified fibrocartilage stem cells (FCSCs) localized within the TMJ condyle superficial zone niche that regenerate cartilage and repair joint injury. Here we investigate the role of Notch in regulating TMJ development and FCSC fate. Using a Notch reporter mouse, we discovered FCSCs localized within the TMJ superficial niche exhibit Notch activity during TMJ morphogenesis. We further showed that constitutively activating Notch promotes FCSC differentiation toward both cartilage and bone lineages, but inhibits adipogenesis. Using a TNF-α-induced TMJ inflammatory arthritis mouse model, we found that the expression of Notch receptors and ligands are upregulated and coupled with cells undergoing cartilage to bone transdifferentiation, which may contribute to TMJ pathogenesis. We also discovered that global Notch inhibition reduces osteogenic and chondrogenic differentiation of FCSCs. Together, these findings suggest that Notch is critical for FCSC fate specification and TMJ homeostasis, and reveal that inhibition of the Notch pathway may be a new therapeutic target for treating TMJ osteoarthritis.

Comparison of Clinical and Semiquantitative Cartilage Grading Systems in Predicting Outcomes After Arthroscopic Partial Meniscectomy

OBJECTIVE. Cartilage loss on preoperative knee MRI is a predictor of poor outcomes after arthroscopic partial meniscectomy. The purpose of this study was to compare the ability to predict outcomes after arthroscopic partial meniscectomy with a clinically used modified Outerbridge system versus a semiquantitative MRI Osteoarthritis Knee Score system for grading cartilage loss. MATERIALS AND METHODS. Patients who underwent preoperative knee MRI within 6 months of arthroscopic partial meniscectomy and who had outcomes available from the time of surgery and 1 year later were eligible for inclusion. Cases were evaluated by two radiologists and one radiology fellow with the use of both grading systems. The accuracy of each system in discriminating between surgical success and failure was estimated using the ROC curve (AUC) with 95% CIs. A Wald test was used to assess noninferiority of the clinical grading system. Interreader agreement regarding the accuracy of the grading systems in predicting outcomes was also compared. RESULTS. A total of 78 patients (38 women and 40 men; mean age, 56.6 years) were included in the study. A prediction model using clinical grading (AUC = 0.695; 95% CI, 0.566-0.824) was noninferior (p = 0.047) to a model using MRI Osteoarthritis Knee Score grading (AUC = 0.683; 95% CI, 0.539-0.827). Both MRI prediction models performed better than a model using demographic characteristics only (AUC = 0.667; 95% CI, 0.522-0.812). Inter-reader agreement with clinical grading (80.8%) was higher than that with MRI Osteoarthritis Knee Score grading (65.0%; p = 0.012). CONCLUSION. A clinically used system to grade cartilage loss on MRI is as effective as a semiquantitative system for predicting outcomes after arthroscopic partial meniscectomy, while also offering improved interreader agreement.

Using Cumulative Load to Explain How Body Mass Index and Daily Walking Relate to Worsening Knee Cartilage Damage Over Two Years: The MOST Study

OBJECTIVE

Knee cartilage damage is often linked to mechanical overloading. However, cartilage requires mechanical load to remain healthy, suggesting that underloading may be detrimental. This study was undertaken to examine knee overloading and underloading by defining cumulative load as the joint effects of body mass index (BMI) and daily walking, and examine the relationship between cumulative load and worsening cartilage damage over 2 years.

METHODS

We used data from the Multicenter Osteoarthritis Study. Steps/day, measured by accelerometry, and BMI were calculated at the 60-month visit. Cartilage damage on magnetic resonance imaging was semiquantitatively scored using the Whole-Organ Magnetic Resonance Imaging Score (WORMS) at the 60-month and 84-month visits; worsening damage was defined as increased WORMS between visits. Risk ratios (RRs) and 95% confidence intervals (95% CIs) were calculated using binomial regression, with adjustment for potential confounders.

RESULTS

Our study included 964 participants, 62% of whom were female, with a mean ± SD age of 66.9 ± 7.5 years. Participants had a mean ± SD BMI of 29.7 ± 4.8 kg/m² and walked a mean ± SD of 7,153 ± 2,591 steps/day. Participants who walked a moderate number of steps/day (6,000-7,900) or a high number of steps/day (>7,900) and had a high BMI (>31 kg/m² ) had a greater risk of worsening medial tibiofemoral (TF) damage (RR 2.83 [95% CI 1.46-5.48] and RR 2.61 [95% CI 1.50-4.54], respectively) compared with those who walked similar steps/day and had a low BMI (18-27 kg/m² ). Participants with a low number of steps/day (<6,000) and a low BMI had a greater risk of worsening medial TF and lateral patellofemoral (PF) damage (RR 2.03 [95% CI 1.06-3.92] and RR 2.28 [95% CI 1.06-4.85], respectively) compared with those who walked a high number of steps/day and had a low BMI. Effect estimates for other compartments of the knee did not reach statistical significance.

CONCLUSION

This study provides preliminary evidence that both overloading and underloading may be detrimental to medial TF cartilage, and underloading may be detrimental to lateral PF cartilage.

Polyurethane Meniscal Scaffold for the Treatment of Partial Meniscal Deficiency: 5-Year Follow-up Outcomes: A European Multicentric Study

BACKGROUND

A biodegradable polyurethane scaffold was developed to treat patients with the challenging clinical condition of painful partial meniscal defects.

HYPOTHESIS

The use of an acellular polyurethane scaffold in patients with symptomatic partial meniscal defects would result in both midterm pain relief and improved function.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 155 patients with symptomatic partial meniscal defects (101 medial and 54 lateral) were implanted with a polyurethane scaffold in a prospective, single-arm, multicentric study with a minimum 5-year follow-up. Clinical outcomes were measured with the visual analog scale for pain, International Knee Documentation Committee subjective knee evaluation form, Lysholm knee scale, and Knee injury and Osteoarthritis Outcome Score at baseline and at 2- and 5-year follow-ups. Magnetic resonance imaging (MRI) was used to evaluate the knee joint, meniscal implant, and meniscal extrusion. Kaplan-Meier survival analysis was also performed. Removal of the scaffold, conversion to a meniscal transplant, and unicompartmental/total knee arthroplasty were used as endpoints.

RESULTS

Eighteen patients were lost to follow-up (11.6%). The patients who were included in this study showed significant clinical improvement after surgery as indicated by the different outcome measures (P = .01). However, the clinical improvement tended to stabilize between 2 and 5 years of follow-up. MRI scans of the scaffolds in 56 patients showed a smaller-sized implant in the majority of the cases when compared with the native meniscus with an irregular surface at the 5-year follow-up. During the follow-up period, 87.6% of the implants survived in this study. At 5 years of follow-up, 87.9% of the medial scaffolds were still functioning versus 86.9% of the lateral scaffolds. In total, 23 treatments had failed: 10 removed scaffolds because of breakage, 7 conversions to meniscal allograft transplantation, 4 conversions to unicompartmental knee arthroplasty, and 2 conversions to total knee arthroplasty.

CONCLUSION

The polyurethane meniscal implant was able to improve knee joint function and reduce pain in patients with segmental meniscal deficiency over 5 years after implantation. The MRI appearance of this scaffold was different from the original meniscal tissue at the midterm follow-up. The treatment survival rates of 87.9% of the medial scaffolds and 86.9% of the lateral scaffolds in the present study compared favorably with those published concerning meniscal allograft transplantation after total meniscectomy.

Biological and Mechanical Predictors of Meniscus Function: Basic Science to Clinical Translation

Progressive knee joint degeneration occurs following removal of a torn meniscus. However, there is significant variability in the rate of development of post-meniscectomy osteoarthritis (OA). While there is no current consensus on the risk factors for development of knee OA in patients with meniscus tears, it is likely that both biological and biomechanical factors play critical roles. In this perspective paper, we review the mechanical and the biological predictors of the response of the knee to partial meniscectomy. We review the role of patient-based studies, in vivo animal models, cadaveric models, bioreactor systems, and statistically augmented computational models for the study of meniscus function and post-meniscectomy OA, providing insight into the important interplay between biomechanical and biologic factors. We then discuss the clinical translation of these concepts for "biologic augmentation" of meniscus healing and meniscus replacement. Ultimately, collaborative studies between engineers, biologists, and clinicians is the optimal way to improve our understanding of meniscus pathology and response to injury and/or disease, and to facilitate effective translation of laboratory findings to improved treatments for our patients. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:937-945, 2020.

Explant models for meniscus metabolism, injury, repair, and healing

Purpose/Aim: Knee meniscus is a wedge-shaped fibrocartilaginous tissue, playing important roles in maintaining joint stability and function. Injuries to the meniscus, particularly with the avascular inner third zone, hardly heal and frequently progress into structural breakdown, followed by the initiation of osteoarthritis. As the importance of meniscus in joint function and diseases is being recognized, the field of meniscus research is growing. Not only development, biology, and metabolism but also injury, repair, and healing of meniscus are being actively investigated. As meniscus functions as an integrated unit of a knee joint, in vivo models with various species have been the predominant method for studying meniscus pathophysiology and for testing healing/regeneration strategies. However, in vivo models for meniscus studies suffer from low reproducibility and high cost. To complement the limitations of in vivo animal models, several types of meniscus explants have been applied as highly controlled, standardized in vitro models to investigate meniscus metabolism, pathophysiology, and repair or regeneration process. This review summarizes and compares the existing meniscus explant models. We also discuss the advantages and disadvantages of each explant model.Conclusion: Despite few outstanding challenges, meniscus explant models have potential to serve as an effective tool for investigations of meniscus metabolism, injury, repair and healing.

Early degeneration of the meniscus revealed by microbiomechanical alteration in a rabbit anterior cruciate ligament transection model

Background

The microbiomechanical properties of the meniscus influence the cell response to the surrounding biomechanical environment ​and are beneficial to understand meniscus repairing and healing. To date, however, this information remains ambiguous. This study aims to characterise the microbiomechanical properties of the meniscus after degeneration in a rabbit anterior cruciate ligament transection (ACLT) model and to analyse the corresponding histology at the macroscale and chemical composition.

Methods

Twenty New Zealand white rabbits were used. Menisci were collected from the knee joints 4 and 8 weeks after the ACLT and from those of the corresponding control groups. The central portions of both medial and lateral menisci were investigated using atomic force microscopy, histological study, and an energy-dispersive spectrometer. The evaluation was conducted regionally within the inner, middle, and outer sites from the top layer (facing the femoral surface) to the bottom layer (facing the tibial surface) in both the lateral and medial menisci to obtain the site-dependent properties.

Results

At 4 weeks after surgery, the dynamic elastic modulus at the microlevel increased significantly at both the top and bottom layers compared with the intact meniscus (P ​= ​0.021). At 8 weeks after surgery, the stiffening occurred in all regions (P ​= ​0.030). The medial meniscus showed greater change than the lateral meniscus. All these microbiomechanical alterations occurred before the histological findings at the macroscale.

Conclusion

The microbiomechanical properties in the meniscus changed significantly after ACLT and were site dependent. Their alterations occurred before the histological changes of degeneration were observed.

The Translational Potential of this Article

The results of our study indicated that degeneration promoted meniscus stiffening. Thus, they provide a better understanding of the disease process affecting the meniscus. Our results might be beneficial to understand how mechanical forces distribute throughout the healthy and pathologic joint. They indicate the possibility of early diagnosis using a minimally invasive arthroscopic tool, as well as they might guide treatment to the healthy and pathologic meniscus and joint.

Varus alignment aggravates tibiofemoral contact pressure rise after sequential medial meniscus resection

PURPOSE

Arthroscopic partial meniscectomy of medial meniscus tears and varus alignment are considered independent risk factors for increased medial compartment load, thus contributing to the development of medial osteoarthritis. The purpose of this biomechanical study was to investigate the effect of lower limb alignment on contact pressure and contact area in the knee joint following sequential medial meniscus resection. It was hypothesized that a meniscal resection of 50% would lead to a significant overload of the medial compartment in varus alignment.

METHODS

Eight fresh-frozen human cadaveric knees were axially loaded with a 750 N compressive force in full extension with the mechanical axis rotated to intersect the tibia plateau at 30%, 40%, 50%, 60% and 70% of its width. Tibiofemoral mean contact pressure (MCP), peak contact pressure (PCP), and contact area (CA) of the medial and lateral compartment were measured separately using pressure-sensitive films (K-Scan 4000, Tekscan) in four different meniscal conditions, respectively, intact, 50% resection, 75% resection, and total meniscectomy.

RESULTS

Medial MCP was significantly increased when comparing the intact meniscus to each meniscal resection in all tested alignments (p < 0.05). Following meniscal resection of 50%, MCP was significantly higher with greater varus alignment compared to valgus alignment (p < 0.05). Similarly, medial PCP was higher at varus alignment compared to valgus alignment (p < 0.05). Further resection to 75% and 100% of the meniscus resulted in a significantly higher medial PCP at 30% of tibia plateau width compared to all other alignments (p < 0.05). Medial CA of the intact meniscus decreased significantly after 50%, 75% and 100% meniscal resection in all alignments (p < 0.05). Lateral joint pressure was not significantly increased by greater valgus alignment.

CONCLUSION

Lower limb alignment and the extent of medial meniscal resection significantly affect tibiofemoral contact pressure. Combined varus alignment and medial meniscal resection increased MCP and PCP within the medial compartment, whereas valgus alignment prevented medial overload. As a clinical consequence, lower limb alignment should be considered in the treatment of patients undergoing arthroscopic partial meniscectomy with concomitant varus alignment. In patients presenting with ongoing medial joint tenderness and effusion, realignment osteotomy can be a surgical technique to unload the medial compartment.

FOXO1 and FOXO3 transcription factors have unique functions in meniscus development and homeostasis during aging and osteoarthritis

The objective of this study was to examine FoxO expression and FoxO function in meniscus. In menisci from human knee joints with osteoarthritis (OA), FoxO1 and 3 expression were significantly reduced compared with normal menisci from young and old normal donors. The expression of FoxO1 and 3 was also significantly reduced in mouse menisci during aging and OA induced by surgical meniscus destabilization or mechanical overuse. Deletion of FoxO1 and combined FoxO1, 3, and 4 deletions induced abnormal postnatal meniscus development in mice and these mutant mice spontaneously displayed meniscus pathology at 6 mo. Mice with Col2Cre-mediated deletion of FoxO3 or FoxO4 had normal meniscus development but had more severe aging-related damage. In mature AcanCreERT2 mice, the deletion of FoxO1, 3, and 4 aggravated meniscus lesions in all experimental OA models. FoxO deletion suppressed autophagy and antioxidant defense genes and altered several meniscus-specific genes. Expression of these genes was modulated by adenoviral FoxO1 in cultured human meniscus cells. These results suggest that FoxO1 plays a key role in meniscus development and maturation, and both FoxO1 and 3 support homeostasis and protect against meniscus damage in response to mechanical overuse and during aging and OA.

FOXO1 and FOXO3 transcription factors have unique functions in meniscus development and homeostasis during aging and osteoarthritis

The objective of this study was to examine FoxO expression and FoxO function in meniscus. In menisci from human knee joints with osteoarthritis (OA), FoxO1 and 3 expression were significantly reduced compared with normal menisci from young and old normal donors. The expression of FoxO1 and 3 was also significantly reduced in mouse menisci during aging and OA induced by surgical meniscus destabilization or mechanical overuse. Deletion of FoxO1 and combined FoxO1, 3, and 4 deletions induced abnormal postnatal meniscus development in mice and these mutant mice spontaneously displayed meniscus pathology at 6 mo. Mice with Col2Cre-mediated deletion of FoxO3 or FoxO4 had normal meniscus development but had more severe aging-related damage. In mature AcanCreERT2 mice, the deletion of FoxO1, 3, and 4 aggravated meniscus lesions in all experimental OA models. FoxO deletion suppressed autophagy and antioxidant defense genes and altered several meniscus-specific genes. Expression of these genes was modulated by adenoviral FoxO1 in cultured human meniscus cells. These results suggest that FoxO1 plays a key role in meniscus development and maturation, and both FoxO1 and 3 support homeostasis and protect against meniscus damage in response to mechanical overuse and during aging and OA.

There Is No Difference in Radiographic Outcomes After Average 9 Years After Arthroscopic Partial Medial Meniscectomy for Both Posterior Horn Tears and Posterior Horn Root Tears

PURPOSE

To compare the serial changes in radiographic outcomes in terms of the mechanical axis (MA) angle and medial joint space width (JSW) between medial meniscus posterior root tear (MM PRT) and non-root tear (MM NRT) after arthroscopic partial meniscectomy (APM).

METHODS

Patients who underwent APM for degenerative MM PRT or MM NRT from January 1999 to July 2012 were retrospectively reviewed. One hundred ten patients each in the MM PRT group and the MM NRT group, who were matched through propensity score matching (adjusting for confounding factors such as age, sex, body mass index, anatomic axis, cartilage state of the medial compartment, and follow-up period), were included in the study. The MA angle on weightbearing whole-leg radiographs and the medial JSW on weightbearing 45° flexion posteroanterior radiographs were measured to evaluate the radiographic outcomes. The serial changes were compared between radiographs taken before surgery, at postoperative 3 to 5 years, and at postoperative 5 years to the last follow-up. The linear mixed model was used to compare the changes in radiographic outcomes during the follow-up period between groups.

RESULTS

The 2 groups were balanced with standardized mean differences of <0.2 after propensity score matching. Both the MM PRT and NRT groups showed increased varus alignment after surgery. However, there was no significant difference in the change in the MA angle during the follow-up period between groups (P = .182). The medial JSW also showed progression of joint space narrowing after surgery in both groups; however, there was no significant difference in the change in medial JSW during the follow-up period between groups (P = .270).

CONCLUSION

The radiographic outcomes after partial meniscectomy in terms of the MA angle and medial JSW show comparable results between degenerative MM PRT and NRT after proper matching of confounding factors.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Every second retired elite female football player has MRI evidence of knee osteoarthritis before age 50 years: a cross-sectional study of clinical and MRI outcomes

PURPOSE

To assess knee health in retired female football players, using magnetic resonance imaging (MRI) and self-report. The focus of analysis were degenerative changes of the tibiofemoral joint, and their relationship to osteoarthritis symptoms and previous knee injury.

METHODS

Forty-nine retired elite, female football players (98 knees) aged 37 years on average participated. Tibiofemoral cartilage and meniscus status of both knees were evaluated using MRI and graded according to modified Outerbridge and Stoller classifications, respectively. Symptoms were assessed through a standardised questionnaire (Knee Osteoarthritis Outcome Score: KOOS). Knee injury history was recorded via a semi-structured interview. To investigate how injury variables relate to outcomes, binary logistic regression models were used and reported with odds ratios (OR).

RESULTS

Fifty-one per cent of players (n = 25) fulfilled the MRI criterion for knee osteoarthritis, 69.4% (n = 34) had substantial meniscal loss and 59.6% (n = 28) reported substantial clinical symptoms. Chondral- and meniscal loss were associated with significantly lower scores on three of five KOOS subscales (p < .05). Both chondral and meniscal loss were significantly predicted by previous traumatic knee injury (OR = 4.6, OR = 2.6), the injury affecting the non-striking leg (OR = 8.6, OR = 10.6) and type of injury; participants with combined ACL/meniscus injuries had the highest risk for substantial chondral and meniscal loss (OR = 14.8, OR = 9.5). Chondral loss was significantly predicted by isolated meniscus injury treated with partial meniscectomy (OR = 5.4), but not by isolated reconstructed ACL injury. Clinical symptoms were only significantly predicted by previous traumatic knee injury (OR = 5.1).

CONCLUSIONS

Serious degenerative changes were found in a high number of retired female football players' knees 10 years after their career. Meniscal integrity is key for knee osteoarthritis outcomes in young adults, and thus, its preservation should be a priority.

Reducing the Volume of Low-Value Outpatient MRI Joint Examinations in Patients ≥55 Years of Age

Purpose:

Magnetic resonance imaging (MRI) is not beneficial in patients with joint pain and concomitant osteoarthritis (OA). We attempt to determine whether evaluation of OA via X-rays can reduce inappropriate MRI and computed tomography (CT) arthrogram use. In our jurisdiction, CT arthrograms are used as surrogate tests because of MRI wait times.

Materials and Methods:

Our intervention required patients ≥55 years of age scheduled for outpatient MRI of the knee/hip/shoulder at an urban hospital to have X-rays (weight bearing when appropriate) from within 1 year. Red flags (ie, neoplasm, infection) were identified for which MRI would be indicated regardless. Through review of radiographs on picture archiving and communication system/digital media and use of the validated Kellgren-Lawrence (KL) OA scale, radiologists assessed the presence and degree of OA. A finding of significant OA (KL > 2) without red flags would preclude MRI. Monthly averages of MRI and CT arthrogram examinations were measured 33 months before and 23 months following introduction of the intervention.

Results:

The proportion of protocoled MRI requisitions that were avoided was 21%. If extrapolated to the province of British Columbia, 2419 of 11 700 examinations could have been prevented in the past year. The average monthly number of knee/hip/shoulder MRI examinations as a percentage of total MRI examinations decreased from 4.9% to 4.3% ( P < .02) following the intervention. The average monthly number of knee/hip/shoulder CT arthrogram examinations decreased from 20.6 to 12.1 ( P < .0001).

Conclusion:

We were able to decrease the number of MRI and CT arthrogram examinations in patients ≥55 years of age with joint pain by implementing an evaluation for OA via recent X-ray imaging.

Medial Meniscus Posterior Root Tear Treatment: A Matched Cohort Comparison of Nonoperative Management, Partial Meniscectomy, and Repair

BACKGROUND

There are limited data comparing the outcomes of similarly matched patients with a medial meniscus posterior root tear (MMPRT) treated with nonoperative management, partial meniscectomy, or repair.

PURPOSE/HYPOTHESIS

The purpose was to compare treatment failure, clinical outcome scores, and radiographic findings for a matched cohort of patients who underwent either nonoperative management, partial meniscectomy, or transtibial pull-through repair for an MMPRT. We hypothesized that patients who underwent meniscus root repair will have lower rates of progression to arthroplasty than patients who were treated with nonoperative management or partial meniscectomy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent transtibial medial meniscus posterior horn root repair were matched by meniscal laterality, age, sex, and Kellgren-Lawrence (K-L) grades to patients treated nonoperatively or with a partial meniscectomy. Progression to arthroplasty rates, International Knee Documentation Committee and Tegner scores, and radiographic outcomes were analyzed between groups.

RESULTS

Forty-five patients were included in this study (15 nonoperative, 15 partial meniscectomy, 15 root repair). Progression to arthroplasty demonstrated significant differences among treatment groups at a mean of 74 months (nonoperative, 4/15; partial meniscectomy, 9/15; meniscal repair, 0/15; P = .0003). The meniscus root repair group had significantly less arthritic progression, as measured by change in K-L grade from pre- to postoperatively (nonoperative, 1.0; partial meniscectomy, 1.1; meniscal repair, 0.1; P = .001).

CONCLUSION

Meniscus root repair leads to significantly less arthritis progression and subsequent knee arthroplasty compared with nonoperative management and partial meniscectomy in a matched cohort based on patient characteristics.

Five Questions to Identify Patients With Osteoarthritis of the Knee

BACKGROUND

To treat the increasing number of patients with osteoarthritis (OA) of the knee, high-volume institutions rely on central referral services as first contact point. Depending on the grading of arthritis, patients will be referred to a nonoperative or operative care provider. The present study reports on a simple 5-step questionnaire to identify patients with OA (Kellgren/Lawrence [KL] grade ≥2) of the knee to improve efficiency of referrals.

METHODS

We included 998 patients who contacted the physician referral service at the author's institution complaining of knee pain and divided them into 2 groups. The study group included patients with an appointment and consisted of 646 patients (345 women [53.4%] and 301 men [46.6%]). X-rays of the knee were graded according to the KL classification system. The control group of patients who did not make an appointment consisted of 352 patients (187 women [53.1%] and 165 men [46.9%]). These patients were contacted to evaluate whether they had been diagnosed with OA of the knee since their initial call, to assure that the study group was not exposed to a selection bias.

RESULTS

Logistic regression revealed 5 questions as significant predictors for OA of the knee (KL grade ≥2). When combining both groups, an 86.9% sensitivity, a 73.3% specificity, and an 84.3% overall accuracy were reached, when patients answered 3 or more questions positively.

CONCLUSION

The present study revealed a simple 5-step questionnaire to identify patients with OA of the knee. Implementation of the questionnaire has the potential to improve the accuracy of referral processes and streamline organization before the first appointment.

How Should We Define Clinically Significant Improvement on Patient-Reported Outcomes Measurement Information System Test for Patients Undergoing Knee Meniscal Surgery?

PURPOSE

The purpose of the study was to define the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) thresholds for the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) computerized adaptive test (CAT) instrument in patients undergoing arthroscopic meniscal surgery.

METHODS

The PROMIS PF CAT was administered preoperatively and postoperatively to patients undergoing arthroscopic meniscal surgery. At 6 months postoperatively, patients graded their knee function based on a domain-specific anchor question. A satisfaction anchor question was used to indicate achievement of the PASS. Receiver operating characteristic analysis determined the relevant psychometric values. Cutoff analysis was performed to find preoperative patient-reported outcome scores predicting achievement of clinically significant outcomes (CSOs).

RESULTS

A total of 73 patients (41.1% female patients) were included, with a mean age of 44.9 ± 12.8.0 years and average follow-up period of 24.0 ± 1.2 weeks. The MCID on the PROMIS PF CAT was calculated to be 2.09 (area under the curve [AUC], 0.75; 95% CI, 0.57-0.94). Net score improvement equivalent to achievement of SCB was found to be 6.50 (AUC, 0.77; 95% CI, 0.55-0.99). The PASS was found to be 46.1 (AUC, 0.86; 95% CI, 0.76-0.96). A preoperative score below 37.6 on the PROMIS PF CAT predicted achievement of the MCID (AUC, 0.76; 95% CI, 0.62-0.87), whereas scores above 41.9 predicted achievement of the PASS (AUC, 0.77; 95% CI, 0.65-0.90). Higher baseline functional status and the absence of pre-existing arthritis were also found to be statistically significant predictors of achieving CSOs.

CONCLUSIONS

Our study defined the MCID, SCB, and PASS for the PROMIS PF CAT. We found that a preoperative score below 37.6 was predictive of achieving a meaningful clinical change with surgery whereas a preoperative score above 41.9 was predictive of patients who would attain an acceptable postoperative health state. In addition, exercising more days per week and the absence of arthritis increased the likelihood of achieving postoperative CSOs.

LEVEL OF EVIDENCE

Level III, retrospective cohort.

Rapid Progression of Knee Pain and Osteoarthritis Biomarkers Greatest for Patients with Combined Obesity and Depression: Data from the Osteoarthritis Initiative

OBJECTIVE

To compare the progression of biochemical biomarkers of osteoarthritis (OA), knee pain, and function between nonobese patients (NON), obese patients without depression (OBESE), and obese patients with comorbid depression (O + D).

DESIGN

Utilizing the FNIH OA Biomarkers Consortium dataset, we categorized knee OA patients into NON, OBESE, and O + D groups based on body mass index and Center for Epidemiological Studies-Depression (CES-D) scores. Subjective symptoms (Knee injury and Osteoarthritis Outcome Score Quality of Life subscale (KOOS QOL), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Physical Function scores, and the Short Form-12 (SF-12) Physical Component Score [PCS]) and objective measures of cartilage degradation and bone remodeling (urinary CTXII and CTXIα) were compared among groups at baseline and 2-year follow-up.

RESULTS

Of the 600 patients, 282 (47%) were NON, 285 (47.5%) OBESE, and 33 (5.5%) O + D. The O + D group had significantly worse pain and function both at baseline and 2-year follow-up (P < 0.001 for all comparisons) as evidenced by self-reported measures on KOOS QOL, WOMAC Pain, WOMAC Physical Function, and SF-12 PCS. The O + D group also demonstrated significant increases in CTXII (P = 0.01) and CTXIα (P = 0.005), whereas the NON and OBESE groups did not.

CONCLUSIONS

The combination of inferior knee pain, physical function, and significantly greater increases in biomarkers of cartilage degradation and bony remodelling suggest a more rapid progression for obese OA patients with comorbid depression. The link between systemic disease, inflammatory burden, and progressive cartilage degradation is in line with increasing concerns about a degenerative synovial environment in early osteoarthritic knees that progress to treatment failure with biologic restoration procedures.

The Association Between History of an Ankle Sprain and Traumatic Meniscal Injury Among Infantry Combat Soldiers in the Israeli Defense Forces: A Historical Cohort Study

Introduction

The high frequency and number of ankle inversion injuries and meniscal injuries in military populations is an area of concern due to the debilitating effects and cumulative consequences of these particular injuries on the soldiers sustaining injury and the consequences on the operational effectiveness of the Israeli Defense Force (IDF). This study examines the possible relationship between ankle inversion injury and potential for subsequent meniscal injury in infantry soldiers in the IDF.

Material and Methods

All 89,069 infantry combat soldiers (including special units), recruited to the IDF between 2007 and 2017 were included in this study. A historical cohort study was conducted. The cohort was divided into two groups: The exposure group included all participants that had suffered at least one ankle sprain in the past and the unexposed group that included all participants who did not suffer an ankle sprain in the past. A Cox proportional-hazards model (COX) model was used in order to obtain the adjusted to confounders association between exposure and outcome expressed in hazard ratio (HR).

Results

The crude association between ankle sprain in the past and the development of meniscal injury in this study was 0.87 (Relative risk = 0.87, P = 0.007). After adjusting for unit type, Body Mass Index (BMI), previous fracture of the lower limb, and the use of eyeglasses, using a COX model, the adjusted association between ankle sprain in the past and the development of meniscal injury was 0.8 (HR = 0.8, P = 0.001, confidence interval (95%) 0.74, 0.88).

Conclusion

The results of this study indicate ankle sprains to be a protective factor for meniscal injury. Our main conclusion from the results of this study is that the assumption that those with previous leg injuries are at a greater risk for further leg injuries is questionable and cannot be generalized. Hence, the association between different types of injuries should be investigated separately.

Accelerated post traumatic osteoarthritis in a dual injury murine model

OBJECTIVE

Joint injury involving destabilisation of the joint and damage to the articular cartilage (e.g., sports-related injury) can result in accelerated post-traumatic osteoarthritis (PTOA). Destabilised medial meniscotibial ligament (DMM) surgery is one of the most commonly used murine models and whilst it recapitulates Osteoarthritis (OA) pathology, it does not necessarily result in multi-tissue injury, as occurs in PTOA. We hypothesised that simultaneous cartilage damage and joint destabilisation would accelerate the onset of OA pathology.

METHODS

OA was induced in C57BL/6 mice via (a) DMM, (b) microblade scratches of articular cartilage (CS) or (c) combined DMM and cartilage scratch (DCS). Mice were culled 7, 14 and 28 days post-surgery. Microcomputed tomography (μCT) and histology were used to monitor bone changes and inflammation. Dynamic weight bearing, an indirect measure of pain, was assessed on day 14.

RESULTS

Osteophytogenesis analysis via μCT revealed that osteophytes were present in all groups at days 7 and 14 post-surgery. However, in DCS, osteophytes were visually larger and more numerous when compared with DMM and cartilage scratch (CS). Histological assessment of cartilage at day 14 and 28, revealed significantly greater damage in DCS compared with DMM and CS. Furthermore, a significant increase in synovitis was observed in DCS. Finally, at day 14 osteophyte numbers correlated with changes in dynamic weight bearing.

CONCLUSION

Joint destabilisation when combined with simultaneous cartilage injury accelerates joint deterioration, as seen in PTOA. Thus, DCS provides a novel and robust model for investigating multiple pathological hallmarks, including osteophytogenesis, cartilage damage, synovitis and OA-related pain.

Three-dimensional microstructure of human meniscus posterior horn in health and osteoarthritis

OBJECTIVE

To develop and perform ex vivo 3D imaging of meniscus posterior horn microstructure using micro-computed tomography (μCT), and to compare specimens from healthy references against end-stage osteoarthritis (OA) using conventional section-based histology and qualitative μCT.

DESIGN

We retrieved human medial and lateral menisci from 10 deceased donors without knee OA (healthy references) and medial and lateral menisci from 10 patients having total knee replacement for medial compartment OA. Meniscal posterior horns were dissected and fixed in formalin. One subsection underwent hexamethyldisilazane (HMDS) treatment and μCT imaging. Pauli's histopathological scoring was performed for 3 other subsections. The differences in histopathological scores were estimated using mixed linear regression, resulting in fixed effects estimates for within-knee comparisons and adjusted for age and body mass index for between-subjects comparisons.

RESULTS

3D visualization with μCT qualitatively revealed similar microstructural changes in the posterior horns as conventional histology. The mean histopathological score was higher for medial menisci from OA knees vs both medial reference menisci (mean difference [95% CI], 3.9 [2.6,5.3]), and lateral menisci from OA knees (3.9 [2.9,5.0]). The scores were similar between lateral menisci from OA knees and lateral reference menisci (0.8 [-0.6,2.2]), and between medial and lateral reference menisci (0.8 [-0.3,1.9]).

CONCLUSIONS

HMDS-based μCT protocol allows unique 3D visualization of meniscus microstructures. Posterior horns of medial menisci from medial compartment OA knees had higher histopathological scores than both the lateral posterior horns from the same OA knees and medial reference menisci, suggesting a strong association between meniscus degradation and unicompartmental knee OA.

Association of meniscal injury to joint space width on standard tibial plateau leveling osteotomy lateral radiographic projections of the canine stifle

Up to 70% of dogs with cranial cruciate ligament tears have concurrent meniscal injury, and these injuries can increase the risk of developing osteoarthritis and persistent lameness. Studies assessing joint space width on knee radiographs in people have indicated associations between joint space width and meniscal injuries. The aim of this prospective analytical study was to determine if there was an association between stifle joint space width on three different radiographic projections (the standard tibial plateau leveling osteotomy projections and a standing lateral projection) and meniscal injuries identified at surgery in dogs. There was a significant association between dogs with a meniscal tear and the corresponding joint space width on standard tibial plateau leveling osteotomy lateral radiographic projections (P-value = .0028). Based on receiver operator characteristic curve analysis, joint space widths measuring less than 3.43 mm may indicate a meniscal tear, with a corresponding 89.5% specificity and 40.5% sensitivity in dogs weighing 31 kg. Joint space narrowing is seen with meniscal tears in dogs, and radiography may be a noninvasive way to identify meniscal tears prior to surgery.

Identification of Pivotal Genes and Pathways in Osteoarthritic Degenerative Meniscal Lesions via Bioinformatics Analysis of the GSE52042 Dataset

Background

To better understand the process of osteoarthritic degenerative meniscal lesions (DMLs) formation, this study analyzed the dataset GSE52042 using bioinformatics methods to identify the pivotal genes and pathways related to osteoarthritic DMLs.

Material/Methods

The GSE52042 dataset, comprising diseased meniscus samples and healthier meniscus samples, was downloaded and the differentially-expressed genes (DEGs) were extracted. The reactome pathways assessment and functional analysis were performed using the “ClusterProfiler” package and “ReactomePA” package of Bioconductor. The protein–protein interaction network was constructed, followed by the extraction of hub genes and modules.

Results

A set of 154 common DEGs, including 64 upregulated DEGs and 90 downregulated DEGs, were obtained. GO analysis suggested that the DEGs primarily participated in positive regulation of the mitotic cell cycle and extracellular matrix organization. Reactome pathway analysis showed that the DEGs were predominantly enriched in TP53, which regulates transcription of genes involved in G2 cell cycle arrest and extracellular matrix organization. The top 10 hub genes were TYMS, AURKA, CENPN, NUSAP1, CENPM, TPX2, CDK1, UBE2C, BIRC5, and CCNB1. The genes in the 2 modules were primarily associated with M Phase and keratan sulfate degradation.

Conclusions

A series of pivotal genes and reactome pathways were identified elucidate the molecular mechanisms involved in the formation of osteoarthritic DMLs and to discover potential therapeutic targets.