Meniscus pathology, osteoarthritis and the treatment controversy

Patient-reported symptoms and changes up to 1 year after meniscal surgery

Background and purpose - Detailed information on the symptoms and limitations that patients with meniscal tears experience is lacking. This study was undertaken to map the most prevalent self-reported symptoms and functional limitations among patients undergoing arthroscopic meniscal surgery and investigate which symptoms and limitations had improved most at 1 year after surgery. Patients and methods - Patients aged 18-76 years from the Knee Arthroscopy Cohort Southern Denmark (KACS) undergoing arthroscopic meniscal surgery were included in this analysis of individual subscale items from the Knee Injury and Osteoarthritis Outcome Score and 1 question on knee stability. Severity of each item was scored as none, mild, moderate, severe, or extreme. Improvements were evaluated using Wilcoxon's signed-rank test and effect size (ES). Results - The most common symptoms were knee grinding and clicking, knee pain in general, pain when twisting and bending the knee and climbing stairs (88-98%), while the most common functional limitations were difficulty bending to the floor, squatting, twisting, kneeling, and knee awareness (97-99%). Knee pain in general and knee awareness improved most 1 year after meniscal surgery (ES -0.47 and -0.45; p < 0.001), while knee instability and general knee difficulties improved least (ES 0.10 and -0.08; p < 0.006). Interpretation - Adults undergoing surgery for a meniscal tear commonly report clinical symptoms and functional limitations related to their daily activities. Moderate improvements were observed in some symptoms and functional limitations and small to no improvement in others at 1 year after surgery. These findings can assist the clinical discussion of symptoms, treatments, and patients' expectations.

Knee menisci segmentation using convolutional neural networks: data from the Osteoarthritis Initiative

OBJECTIVE

To present a novel method for automated segmentation of knee menisci from MRIs. To evaluate quantitative meniscal biomarkers for osteoarthritis (OA) estimated thereof.

METHOD

A segmentation method employing convolutional neural networks in combination with statistical shape models was developed. Accuracy was evaluated on 88 manual segmentations. Meniscal volume, tibial coverage, and meniscal extrusion were computed and tested for differences between groups of OA, joint space narrowing (JSN), and WOMAC pain. Correlation between computed meniscal extrusion and MRI Osteoarthritis Knee Score (MOAKS) experts' readings was evaluated for 600 subjects. Suitability of biomarkers for predicting incident radiographic OA from baseline to 24 months was tested on a group of 552 patients (184 incident OA, 386 controls) by performing conditional logistic regression.

RESULTS

Segmentation accuracy measured as dice similarity coefficient was 83.8% for medial menisci (MM) and 88.9% for lateral menisci (LM) at baseline, and 83.1% and 88.3% at 12-month follow-up. Medial tibial coverage was significantly lower for arthritic cases compared to non-arthritic ones. Medial meniscal extrusion was significantly higher for arthritic knees. A moderate correlation between automatically computed medial meniscal extrusion and experts' readings was found (ρ = 0.44). Mean medial meniscal extrusion was significantly greater for incident OA cases compared to controls (1.16 ± 0.93 mm vs 0.83 ± 0.92 mm; P < 0.05).

CONCLUSION

Especially for medial menisci an excellent segmentation accuracy was achieved. Our meniscal biomarkers were validated by comparison to experts' readings as well as analysis of differences w.r.t groups of OA, JSN, and WOMAC pain. It was confirmed that medial meniscal extrusion is a predictor for incident OA.

Willingness of older adults to participate in a randomized trial of conservative therapies for knee pain: A prospective preference assessment

Background

In preparation for a trial of physical therapy (PT) for patients with degenerative meniscal tear and knee osteoarthritis, we conducted a prospective preference assessment -- a methodology for estimating the proportion of eligible subjects who would participate in a hypothetical randomized trial.

Methods

We identified patients seeking care from the practices of five orthopedic surgeons. Patients completed a survey asking about their willingness to participate in a hypothetical trial, their treatment preferences, their knee pain, and demographic variables.

Results

We approached 201 eligible patients, of whom 67% (95% confidence interval [CI] 60%, 73%) completed questionnaires. Of these, 24% (95% CI 17%, 31%) were definitely and 39% (95% CI 31%, 47%) were probably willing to participate in the trial. Thirty-three percent (95% CI 23%, 43%) of subjects with no treatment preference were definitely willing to participate as compared to 9% (95% CI 1%, 17%) with treatment preference (p = .001). Patients with higher educational attainment also stated a greater willingness to participate than those with less education (p = .06). In multivariable logistic regression analysis, those with no treatment preferences had greater adjusted odds of stating they would definitely participate than those with a defined treatment preference (OR 5.2, 95% CI 1.7, 16.2), while subjects with an associate's degree or greater were more likely to state they would definitely participate than those with less education (OR 3.9, 95% CI 1.1, 14.1).

Conclusion

In this prospective preference assessment, 63% (95% CI 55%, 71%) of subjects with degenerative meniscal tear expressed willingness to participate in a trial of PT modalities. Individuals with no treatment preferences were more likely to state they would participate than were those with higher education. This methodology can help investigators estimate recruitment rates, anticipate generalizability of the trial sample and create strategies to facilitate enrollment.

Annual trends in arthroscopic meniscus surgery: Analysis of a national database in Japan

Background

The importance of meniscus preservation is widely recognized. There have been a few studies describing trends in meniscectomy and meniscus repair in the United States; however, they presented differing results. We reported annual trends in meniscus surgery, using a national database in Japan.

Methods

We interrogated the Diagnosis Procedure Combination database, which represents approximately half of all hospital admissions in Japan. We included the patients who underwent meniscectomy and meniscus repair between July 2007 and March 2015. The diagnosis, age and sex of each patient were recorded.

Results

We identified 83,105 patients: 69,310 underwent meniscectomy; 13,416 underwent meniscus repair and 379 underwent both in a single admission. The proportion of patients undergoing meniscus repair rose from 7.0% in 2007 to 25.9% in 2014 (p < 0.001), while the proportion undergoing meniscectomy fell from 92.8% in 2007 to 73.3% in 2014 (p < 0.001). Among patients under 30 years old, the proportions undergoing meniscus repair or meniscectomy in 2014 were 50.3% versus 48.3%, respectively. A bimodal age distribution was observed for meniscectomy, with peaks at 10–19 years of age and 60–69 years of age, whereas most patients undergoing meniscus repair were 10–19 years of age.

Conclusions

We found characteristic trends where the popularity of meniscus repair increased rapidly at the expense of meniscectomy in Japan during the study period. In the last survey year, the proportion of meniscus repair exceeded that of meniscectomy in those younger than 30 years. Meniscectomy was undertaken most often in adolescents and early old age, while meniscus repair was undertaken most often in adolescents.

Large meniscus extrusion ratio is a poor prognostic factor of conservative treatment for medial meniscus posterior root tear

PURPOSE

The purpose of this study was to find a prognostic factor of medial meniscus posterior root tear (MMPRT) for surgical decision making.

METHODS

Eighty-eight patients who were diagnosed as acute or subacute MMPRT without severe degeneration of the meniscus were treated conservatively for 3 months. Fifty-seven patients with MMPRT showed good response to conservative treatment (group 1), while the remaining 31 patients who failed to conservative treatment (group 2) received arthroscopic meniscus repair. Their demographic characteristics and radiographic features including hip-knee-ankle angle, joint line convergence angle, Kellgren-Lawrence grade in plain radiographs, meniscus extrusion (ME) ratio (ME-medial femoral condyle ratio, ME-medial tibial plateau ratio, ME-meniscus width ratio), the location of bony edema, and cartilage lesions in MRI were compared. Receiver operating characteristic (ROC) curve analysis was also performed to determine the cut-off values of risk factors.

RESULTS

The degree of ME-medial femoral condyle and medial tibia plateau ratio of group 2 was significantly higher than group 1 (0.08 and 0.07 vs. 0.1 and 0.09, respectively, both p < 0.001). No significant (n.s.) difference in other variables was found between the two groups. On ROC curve analysis, ME-medial femoral condyle ratio was confirmed as the most reliable prognostic factor of conservative treatment for MMPRT (area under ROC = 0.8).

CONCLUSION

The large meniscus extrusion ratio was the most reliable poor prognostic factor of conservative treatment for MMPRT. Therefore, for MMPRT patients with large meniscus extrusion, early surgical repair could be considered as the primary treatment option.

LEVEL OF EVIDENCE

III.

Transcriptome comparison of meniscus from patients with and without osteoarthritis

OBJECTIVE

To assess the impact of osteoarthritis (OA) on the meniscus by comparing transcripts and biological processes in the meniscus between patients with and without OA.

DESIGN

RNA microarrays were used to identify transcripts differentially expressed (DE) in meniscus obtained from 12 OA and 12 non-OA patients. The non-OA specimens were obtained at the time of arthroscopic partial meniscectomy. Real-time PCR was performed on selected transcripts. Biological processes and gene-networking was examined computationally. Transcriptome signatures were mapped with 37 OA-related transcripts to evaluate how meniscus gene expression relates to that of OA cartilage.

RESULTS

We identified 168 transcripts significantly DE between OA (75 elevated, 93 repressed) and non-OA samples (≥1.5-fold). Among these, CSN1S1, COL10A1, WIF1, and SPARCL1 were the most prominent transcripts elevated in OA meniscus, POSTN and VEGFA were most highly repressed in OA meniscus. Transcripts elevated in OA meniscus represented response to external stimuli, cell migration and cell localization while those repressed in OA meniscus represented histone deacetylase activity (related to epigenetics) and skeletal development. Numerous long non-coding RNAs (lncRNAs) were DE between the two groups. When segregated by OA-related transcripts, two distinct clustering patterns appeared: OA meniscus appeared to be more inflammatory while non-OA meniscus exhibited a "repair" phenotype.

CONCLUSIONS

Numerous transcripts with potential relevance to the pathogenesis of OA are DE in OA and non-OA meniscus. These data suggest an involvement of epigenetically regulated histone deacetylation in meniscus tears as well as expression of lncRNAs. Patient clustering based on transcripts related to OA in articular cartilage confirmed distinct phenotypes between injured (non-OA) and OA meniscus.

Native tissue-based strategies for meniscus repair and regeneration

Meniscus injuries appear to be becoming increasingly common and pose a challenge for orthopedic surgeons. However, there is no curative approach for dealing with defects in the inner meniscus region due to its avascular nature. Numerous strategies have been applied to regenerate and repair meniscus defects and native tissue-based strategies have received much attention. Native tissue usually has good biocompatibility, excellent mechanical properties and a suitable microenvironment for cellular growth, adhesion, redifferentiation, extracellular matrix deposition and remodeling. Classically, native tissue-based strategies for meniscus repair and regeneration are divided into autogenous and heterogeneous tissue transplantation. Autogenous tissue transplantation is performed more widely than heterogeneous tissue transplantation because there is no immunological rejection and the success rates are higher. This review first discusses the native meniscus structure and function and then focuses on the use of the autogenous tissue for meniscus repair and regeneration. Finally, it summarizes the advantages and disadvantages of heterogeneous tissue transplantation. We hope that this review provides some suggestions for the future design of meniscus repair and regeneration strategies.

Risk factors, diagnosis and non-surgical treatment for meniscal tears: evidence and recommendations: a statement paper commissioned by the Danish Society of Sports Physical Therapy (DSSF)

This statement aimed at summarising and appraising the available evidence for risk factors, diagnostic tools and non-surgical treatments for patients with meniscal tears. We systematically searched electronic databases using a pragmatic search strategy approach. Included studies were synthesised quantitatively or qualitatively, as appropriate. Strength of evidence was determined according to the Grading of Recommendations Assessment Development and Evaluation framework. Low-quality evidence suggested that overweight (degenerative tears, k=3), male sex (k=4), contact and pivoting sports (k=2), and frequent occupational kneeling/squatting (k=3) were risk factors for meniscal tears. There was low to moderate quality evidence for low to high positive and negative predictive values, depending on the underlying prevalence of meniscal tears for four common diagnostic tests (k=15, n=2474). Seven trials investigated exercise versus surgery (k=2) or the effect of surgery in addition to exercise (k=5) for degenerative meniscal tears. There was moderate level of evidence for exercise improving self-reported pain (Effect Size (ES)-0.51, 95% CI -1.16 to 0.13) and function (ES -0.06, 95% CI -0.23 to 0.11) to the same extent as surgery, and improving muscle strength to a greater extent than surgery (ES -0.45, 95% CI -0.62 to -0.29). High-quality evidence showed no clinically relevant effect of surgery in addition to exercise on pain (ES 0.18, 95% 0.05 to 0.32) and function (ES, 0.13 95% CI -0.03 to 0.28) for patients with degenerative meniscal tears. No randomised trials comparing non-surgical treatments with surgery in patients younger than 40 years of age or patients with traumatic meniscal tears were identified. Diagnosis of meniscal tears is challenging as all clinical diagnostic tests have high risk of misclassification. Exercise therapy should be recommended as the treatment of choice for middle-aged and older patients with degenerative meniscal lesions. Evidence on the best treatment for young patients and patients with traumatic meniscal tears is lacking.

Arthroscopic meniscectomy for degenerative meniscal tears reduces knee pain but is not cost-effective in a routine health care setting: a multi-center longitudinal observational study using data from the osteoarthritis initiative

OBJECTIVES

It is disputed whether arthroscopic meniscectomy is an (cost-) effective treatment for degenerative meniscus tears in day-to-day clinical practice. The objective of this study was to assess the cost-effectiveness of arthroscopic meniscectomy in subjects with knee osteoarthritis, in routine clinical practice, while taking into account the increased risk for future knee replacement surgery. We compared cost-effectiveness of arthroscopic meniscectomy compared to no surgery.

DESIGN

We used a state transition (Markov) simulation model to evaluate the cost-effectiveness of arthroscopic meniscectomy compared to no surgery in subjects with knee osteoarthritis (age range 45-79 years). Data used in the preparation of the current study were obtained from the Osteoarthritis Initiative (AOI) database. We applied a 9 years' time horizon (which is equal to the current OAI study follow up period), and evaluated cost-effectiveness from a societal perspective. The main outcome measure was the incremental cost-effectiveness ratio (Euros per quality adjusted life-year (QALY) gained).

RESULTS

Arthroscopic meniscectomy was associated with 8.09 (SD ± 0.07) QALYs at a cost of € 21,345 (SD ± 841), whereas the no surgery was associated with 8.05 (SD ± 0.07) QALYs at a cost of € 16,284 (SD ± 855). For arthroscopic meniscectomy, the incremental cost per QALY gained was € 150,754.

CONCLUSIONS

In day-to-day clinical practice, arthroscopic meniscectomy in subjects with knee osteoarthritis is associated with € 150,754 per QALY gained, which exceeds the generally accepted willingness to pay (WTP) (range € 20,000-€ 80,000).

Meniscus surgery is still widely performed in the treatment of degenerative meniscus tears in The Netherlands

PURPOSE

Studies have demonstrated rising incidences of meniscus procedures for degenerative meniscus tears in several countries, despite accumulating evidence that questions the efficacy of the treatment. It is not clear if this rise in incidences also applies to the practice of arthroscopic surgery in the Netherlands. The objective of this study was, therefore, to evaluate the number of meniscal surgeries performed in the Netherlands between 2005 and 2014.

METHODS

We used registry-based data on meniscal surgeries that originated from Dutch national hospital basic care registrations from 2005 to 2014. Poisson regression models were used to test differences in incidences of meniscus surgeries performed in the Netherlands between 2005 and 2014, and to find out if changes in incidences over this period differed for younger and older patients.

RESULTS

The number of meniscus surgeries was highest in patients aged 40-65 years, who accounted for half of the total number of meniscal surgeries. The incidences of meniscus surgeries decreased from 2005 to 2014 (p < 0.001); this decrease was observed in all age groups, although the decrease in incidences was more pronounced for younger patients (aged less than 40 years) compared to middle-aged and older patients (aged 40 years and older) (p < 0.001).

CONCLUSIONS

The implementation of a nationwide guideline for arthroscopic procedures for meniscus tears may have contributed to a decrease in incidences of meniscus procedures. Despite accumulating evidence that questions the rationalisation and effectiveness of the treatment, meniscus surgery is still widely performed in the treatment of degenerative meniscus tears in the Netherlands, demonstrating a delay in the dissemination, acceptance, and implementation of clinical evidence in the practice of arthroscopic surgery in the Netherlands.

LEVEL OF EVIDENCE

II.

Where does meniscal damage progress most rapidly? An analysis using three-dimensional shape models on data from the Osteoarthritis Initiative

OBJECTIVES

Meniscal pathology is integral to knee osteoarthritis (OA) and its progression; it provides a progression biomarker and a potential treatment target. Magnetic resonance imaging (MRI) demonstrates large heterogeneity in meniscal damage; this structural complexity means measurement is difficult. The aim of this study was to apply novel 3D image analysis to determine which meniscal pathologies demonstrated most change during OA progression.

METHODS

Knee images were selected from the progression cohort of the Osteoarthritis Initiative choosing participants with risk factors for medial OA progression. Medial and lateral menisci were manually segmented then analysed using a statistical shape model of the tibia as a reference surface. Responsiveness was assessed at 1 year using standardised response means (SRMs) for four constructs: meniscal volume, extrusion volume, thickness and tibial coverage; anatomical sub-regions of these constructs were also explored.

RESULTS

Paired images from 86 participants (median age 61.5, 49% female, 56% obese) were included. Reliability of the novel meniscal measurements was very good intraclass correlation coefficients (ICCs all > 0.98). Meniscal volume and extrusion demonstrated no significant change. Moderate responsiveness was observed for medial meniscus thickness (SRM -0.35) and medial tibial coverage (SRM -0.36). No substantial change was seen for the lateral meniscus measures. Sub-region analysis did not improve responsiveness; while greater change was seen in the posterior medial compartment, it was associated with increased variance of the change.

CONCLUSIONS

The location of meniscal damage was consistently in the posterior medial region, and two measurements (thickness and tibial coverage) were most responsive. Meniscal measures should add to discriminatory power in OA progression assessment.

Concomitant injuries may not reduce the likelihood of achieving symmetrical muscle function one year after anterior cruciate ligament reconstruction: a prospective observational study based on 263 patients

PURPOSE

A better understanding of patient characteristics and the way common concomitant injuries affect the recovery of muscle function after surgery should help providers to treat patients with anterior cruciate ligament (ACL) injuries. The aim of this study was to determine whether patient characteristics, concomitant injuries and graft choice at ACL reconstruction were associated with symmetrical knee muscle function at one year. The hypothesis was that the presence of concomitant injuries would negatively influence the opportunity to achieve symmetrical knee function at the one-year follow-up.

METHODS

Data was extracted from the Swedish National Knee Ligament Register and a rehabilitation outcome register between August 2012 and December 2016. The patients had been evaluated with a battery of tests comprising knee extension and flexion strength, vertical jump, hop for distance and the side-hop test one year after ACL reconstruction. Univariable and multivariable logistic regression analyses were performed with achieving a limb symmetry index (LSI) of ≥ 90% in all tests of muscle function as primary outcome.

RESULTS

A total of 263 patients with a mean age of 26.7 ± 10.3 years were included in the study (47% females). No patient demographic or intra-operative predictors were found to be significant when attempting to predict the achievement of a symmetrical muscle function. Lateral meniscus injury and a patellar tendon autograft reduced the odds of achieving an LSI of ≥ 90% in knee extension strength, OR = 0.49 [(95% CI 0.25-0.97), p = 0.039] and OR = 0.30 [(95% CI 0.14-0.67), p = 0.0033] respectively. In addition, reduced odds of recovering knee extension strength were found in older patients, OR = 0.76 [(95% CI 0.60-0.98), p = 0.034]. A higher pre-injury level of physical activity increased the odds of recovering knee flexion strength, OR = 1.14 [(95% CI 1.01-1.29), p = 0.037].

CONCLUSION

Intra-operatively identified concomitant injuries or graft choice did not affect the likelihood of recovering symmetrical performance in five different tests of muscle function one year after ACL reconstruction. However, fewer than one in four patients achieved an LSI of ≥ 90% in all tests.

LEVEL OF EVIDENCE

Prospective observational study: Level 2.

Conservative Management of Possible Meniscal Derangement Using the Mulligan Concept: A Case Report

Objective

The purpose of this case study was to report on the immediate effects of the combined use of mobilizations with movement and the "squeeze" technique on a patient with knee stiffness, popping, and swelling.

Clinical Features

The patient presented with right knee stiffness, swelling, and a popping sensation of insidious onset. Clinical examination revealed pain with terminal knee extension and flexion, joint line tenderness, a positive Apley's compression test, and a positive Thessaly's test at 20° of knee flexion. A working diagnosis was established of a meniscal pathology with the differential diagnoses of meniscal derangement and synovial plica.

Intervention and Outcome

The patient received 3 total treatments using the Mulligan concept over the course of 11 days. The treatments included the application of a tibia internal rotation mobilization with movement and the "squeeze" technique to the affected knee. Patient outcomes, including the Disablement in the Physically Active Scale, the Patient-Specific Functional Scale, and the Numeric Rating Scale for pain, were collected throughout the course of treatment. The patient reported a minimal clinically important difference on the Numeric Rating Scale for pain after each treatment and on all outcomes after the third treatment. The patient reported improvement on her follow-up visit 4 days after the third treatment; the results of a clinical exam and patient outcomes supported a complete discharge after 3 treatments.

Conclusion

This patient responded favorably to use of the Mulligan concept as a manual therapy technique for the treatment of symptoms related to possible meniscal derangement.

Middle-aged patients with an MRI-verified medial meniscal tear report symptoms commonly associated with knee osteoarthritis

Background and purpose - No consensus exists on when to perform arthroscopic partial meniscectomy in patients with a degenerative meniscal tear. Since MRI and clinical tests are not accurate in detecting a symptomatic meniscal lesion, the patient's symptoms often play a large role when deciding when to perform surgery. We determined the prevalence and severity of self-reported knee symptoms in patients eligible for arthroscopic partial meniscectomy due to a degenerative meniscal tear. We investigated whether symptoms commonly considered to be related to meniscus injury were associated with early radiographic signs of knee osteoarthritis. Patients and methods - We included individual baseline items from the Knee injury and Osteoarthritis Outcome Score collected in 2 randomized controlled trials evaluating treatment for an MRI-verified degenerative medial meniscal tears in 199 patients aged 35-65 years. Each item was scored as no, mild, moderate, severe, extreme, and at least "mild" considering the symptoms present. Early radiographic signs of osteoarthritis, defined as a Kellgren and Lawrence grade of at least 1, were seen in 70 patients. Results - At least monthly knee pain, pain during stair walking and when twisting on the knee, and lack of confidence in knee was present in at least 80% of the patients. Median severity was at least moderate for knee pain, pain when twisting on the knee, pain walking on stairs, lack of confidence in knee, and clicking. Mechanical symptoms such as catching were rare. Early radiographic signs of osteoarthritis were associated with an increased risk of self-reported swelling, catching, and stiffness later in the day; the odds ratio was 2.4 (95% CI 1.2-4.9), 2.3 (1.2-4.3), and 2.3 (1.1-5.0), respectively. Interpretation - Middle-aged patients with a degenerative medial meniscus tear reported symptoms commonly associated with knee osteoarthritis. Frequent knee pain, presence of lack of confidence in the knee, and clicking did not distinguish those with a meniscal tear alone from those with early radiographic knee OA. Our findings support the notion that symptoms reported by those with a degenerative meniscal tear represent early signs of knee osteoarthritis.

Can we predict the clinical outcome of arthroscopic partial meniscectomy? A systematic review

NHS-Prospero registration number

42016048592

Objective

In order to make a more evidence-based selection of patients who would benefit the most from arthroscopic partial meniscectomy (APM), knowledge of prognostic factors is essential. We conducted a systematic review of predictors for the clinical outcome following APM.

Design

Systematic review

Data sources

Medline, Embase, Cochrane Central Register, Web of Science, SPORTDiscus, PubMed Publisher, Google Scholar

Inclusion criteria

Report an association between factor(s) and clinical outcome; validated questionnaire; follow-up >1 year.

Exclusion criteria

<20 subjects; anterior cruciate ligament-deficient patients; discoid menisci; meniscus repair, transplantation or implants; total or open meniscectomy.

Methods

One reviewer extracted the data, two reviewers assessed the risk of bias and performed a best-evidence synthesis.

Results

Finally, 32 studies met the inclusion criteria. Moderate evidence was found, that the presence of radiological knee osteoarthritis at baseline and longer duration of symptoms (>1 year) are associated with worse clinical outcome following APM. In addition, resecting >50% of meniscal tissue and leaving a non-intact meniscal rim after meniscectomy are intra-articular predictive factors for worse clinical outcome. Moderate evidence was found that sex, onset of symptoms (acute or chronic), tear type or preoperative sport level are not predictors for clinical outcome. Conflicting evidence was found for the prognostic value of age, perioperative chondral damage, body mass index and leg alignment.

Summary/conclusion

Long duration of symptoms (>1 year), radiological knee osteoarthritis and resecting >50% of meniscus are associated with a worse clinical outcome following APM. These prognostic factors should be considered in clinical decision making for patients with meniscal tears.

Association of medial meniscal extrusion with medial tibial osteophyte distance detected by T2 mapping MRI in patients with early-stage knee osteoarthritis

Background

Medial meniscal extrusion (MME) is associated with progression of medial knee osteoarthritis (OA), but no or little information is available for relationships between MME and osteophytes, which are found in cartilage and bone parts. Because of the limitation in detectability of the cartilage part of osteophytes by radiography or conventional magnetic resonance imaging (MRI), the rate of development and size of osteophytes appear to have been underestimated. Because T2 mapping MRI may enable us to evaluate the cartilage part of osteophytes, we aimed to examine the association between MME and OA-related changes, including osteophytes, by using conventional and T2 mapping MRI.

Methods

Patients with early-stage knee OA (n = 50) were examined. MRI-detected OA-related changes, in addition to MME, were evaluated according to the Whole-Organ Magnetic Resonance Imaging Score. T2 values of the medial meniscus and osteophytes were measured on T2 mapping images. Osteophytes surgically removed from patients with end-stage knee OA were histologically analyzed and compared with findings derived by radiography and MRI.

Results

Medial side osteophytes were detected by T2 mapping MRI in 98% of patients with early-stage knee OA, although the detection rate was 48% by conventional MRI and 40% by radiography. Among the OA-related changes, medial tibial osteophyte distance was most closely associated with MME, as determined by multiple logistic regression analysis, in the patients with early-stage knee OA (β = 0.711, p < 0.001). T2 values of the medial meniscus were directly correlated with MME in patients with early-stage knee OA, who showed ≥ 3 mm of MME (r = 0.58, p = 0.003). The accuracy of osteophyte evaluation by T2 mapping MRI was confirmed by histological analysis of the osteophytes removed from patients with end-stage knee OA.

Conclusions

Our study demonstrates that medial tibial osteophyte evaluated by T2 mapping MRI is frequently observed in the patients with early-stage knee OA, showing close association with MME, and that MME is positively correlated with the meniscal degeneration.

Knee Arthroscopic Surgery in Middle-Aged Patients With Meniscal Symptoms: A 3-Year Follow-up of a Prospective, Randomized Study

BACKGROUND

The optimal treatment for middle-aged patients with knee pain and meniscal lesions has been extensively debated. Most previous studies have revealed only short-term beneficial results of knee arthroscopic surgery. The authors have previously shown a positive benefit of knee arthroscopic surgery and an exercise program after 1 year when compared with an exercise program alone.

PURPOSE

To evaluate if knee arthroscopic surgery combined with an exercise program provided an additional long-term benefit after 3 years compared with an exercise program alone in middle-aged patients with meniscal symptoms.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Of 179 eligible patients, aged 45 to 64 years, 150 were randomized to (1) a 3-month exercise program (nonsurgery group) or (2) the same as group 1 plus knee arthroscopic surgery within 4 weeks (surgery group). The primary outcome was the change in the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscore of pain between baseline and the 3-year follow-up. Results from the 1-year follow-up have been published previously.

RESULTS

Both treatment groups improved significantly in the KOOS pain subscore at 3 years' follow-up in the intention-to-treat and as-treated analyses ( P < .001). The between-group difference for the change in the KOOS pain subscore between baseline and the 3-year follow-up was no longer statistically significant, neither in the intention-to-treat analysis (7.6 points; 95% CI, -0.6 to 15.9; P = .068) nor in the as-treated analysis (5.3 points; 95% CI, -3.1 to 13.8; P = .216). The factorial analysis of the effect of the intervention and age, onset of pain, and mechanical symptoms indicated that older patients improved more, regardless of treatment, and surgery may be more beneficial for patients without mechanical symptoms (as-treated analysis). The effect of the predictive factors on the KOOS pain subscore was uncertain because of the small sample size in the subgroup analyses.

CONCLUSION

The benefit of knee arthroscopic surgery, seen at 1 year in middle-aged patients with meniscal symptoms, was diminished at 3 years and was no longer statistically significant.

CLINICAL RELEVANCE

Knee arthroscopic surgery may be beneficial for middle-aged patients with meniscal symptoms in addition to an exercise program. Older age and absence of mechanical symptoms should not be contraindications to surgery. Registration: NCT01288768 ( ClinicalTrials.gov identifier).

Post-Traumatic Osteoarthritis in Mice Following Mechanical Injury to the Synovial Joint

We investigated the spectrum of lesions characteristic of post-traumatic osteoarthritis (PTOA) across the knee joint in response to mechanical injury. We hypothesized that alteration in knee joint stability in mice reproduces molecular and structural features of PTOA that would suggest potential therapeutic targets in humans. The right knees of eight-week old male mice from two recombinant inbred lines (LGXSM-6 and LGXSM-33) were subjected to axial tibial compression. Three separate loading magnitudes were applied: 6N, 9N, and 12N. Left knees served as non-loaded controls. Mice were sacrificed at 5, 9, 14, 28, and 56 days post-loading and whole knee joint changes were assessed by histology, immunostaining, micro-CT, and magnetic resonance imaging. We observed that tibial compression disrupted joint stability by rupturing the anterior cruciate ligament (except for 6N) and instigated a cascade of temporal and topographical features of PTOA. These features included cartilage extracellular matrix loss without proteoglycan replacement, chondrocyte apoptosis at day 5, synovitis present at day 14, osteophytes, ectopic calcification, and meniscus pathology. These findings provide a plausible model and a whole-joint approach for how joint injury in humans leads to PTOA. Chondrocyte apoptosis, synovitis, and ectopic calcification appear to be targets for potential therapeutic intervention.

Cell-Based Meniscus Repair and Regeneration: At the Brink of Clinical Translation?: A Systematic Review of Preclinical Studies

Background:

Meniscus damage can be caused by trauma or degeneration and is therefore common among patients of all ages. Repair or regeneration of the menisci could be of great importance not only for pain relief or regaining function but also to prevent degenerative disease and osteoarthritis. Current treatment does not offer consistent long-term improvement. Although preclinical research focusing on augmentation of meniscal tear repair and regeneration after meniscectomy is encouraging, clinical translation remains difficult.

Purpose:

To systematically evaluate the literature on in vivo meniscus regeneration and explore the optimal cell sources and conditions for clinical translation. We aimed at thorough evaluation of current evidence as well as clarifying the challenges for future preclinical and clinical studies.

Study Design:

Systematic review.

Methods:

A search was conducted using the electronic databases of MEDLINE, Embase, and the Cochrane Collaboration. Search terms included meniscus, regeneration, and cell-based.

Results:

After screening 81 articles based on title and abstract, 51 articles on in vivo meniscus regeneration could be included; 2 additional articles were identified from the references. Repair and regeneration of the meniscus has been described by intra-articular injection of multipotent mesenchymal stromal (stem) cells from adipose tissue, bone marrow, synovium, or meniscus or the use of these cell types in combination with implantable or injectable scaffolds. The use of fibrochondrocytes, chondrocytes, and transfected myoblasts for meniscus repair and regeneration is limited to the combination with different scaffolds. The comparative in vitro and in vivo studies mentioned in this review indicate that the use of allogeneic cells is as successful as the use of autologous cells. In addition, the implantation or injection of cell-seeded scaffolds increased tissue regeneration and led to better structural organization compared with scaffold implantation or injection of a scaffold alone. None of the studies mentioned in this review compare the effectiveness of different (cell-seeded) scaffolds.

Conclusion:

There is heterogeneity in animal models, cell types, and scaffolds used, and limited comparative studies are available. The comparative in vivo research that is currently available is insufficient to draw strong conclusions as to which cell type is the most promising. However, there is a vast amount of in vivo research on the use of different types of multipotent mesenchymal stromal (stem) cells in different experimental settings, and good results are reported in terms of tissue formation. None of these studies compare the effectiveness of different cell-scaffold combinations, making it hard to conclude which scaffold has the greatest potential.

Cartilage morphology at 2-3 years following anterior cruciate ligament reconstruction with or without concomitant meniscal pathology

PURPOSE

To examine differences in cartilage morphology between young adults 2-3 years post-anterior cruciate ligament reconstruction (ACLR), with or without meniscal pathology, and control participants.

METHODS

Knee MRI was performed on 130 participants aged 18-40 years (62 with isolated ACLR, 38 with combined ACLR and meniscal pathology, and 30 healthy controls). Cartilage defects, cartilage volume and bone marrow lesions (BMLs) were assessed from MRI using validated methods.

RESULTS

Cartilage defects were more prevalent in the isolated ACLR (69 %) and combined group (84 %) than in controls (10 %, P < 0.001). Furthermore, the combined group showed higher prevalence of cartilage defects on medial femoral condyle (OR 4.7, 95 % CI 1.3-16.6) and patella (OR 7.8, 95 % CI 1.5-40.7) than the isolated ACLR group. Cartilage volume was lower in both ACLR groups compared with controls (medial tibia, lateral tibia and patella, P < 0.05), whilst prevalence of BMLs was higher on lateral tibia (P < 0.001), with no significant differences between the two ACLR groups for either measure.

CONCLUSIONS

Cartilage morphology was worse in ACLR patients compared with healthy controls. ACLR patients with associated meniscal pathology have a higher prevalence of cartilage defects than ACLR patients without meniscal pathology. The findings suggest that concomitant meniscal pathology may lead to a greater risk of future OA than isolated ACLR.

LEVEL OF EVIDENCE

III.

Recovery of lower extremity muscle strength and functional performance in middle-aged patients undergoing arthroscopic partial meniscectomy

PURPOSE

To investigate lower extremity muscle strength and functional performance before and after arthroscopic partial meniscectomy in middle-aged patients with degenerative meniscal tears. We hypothesized that patients would experience deficiencies in the affected leg at 3 months post-surgery, and that this deficiency would be normalized at 12 months following surgery.

METHODS

Twenty-three patients (46 ± 6.5 years) meniscectomized in 2012 and 2013 were examined for knee extension, knee flexion, and hip abduction maximal isometric muscle strength (iMVC), rate of force development (RFD₂₀₀), and knee function (single-leg hop for distance and single-leg knee bends in 30 s.) before surgery, 3 and 12 months after surgery.

RESULTS

Functional performance, knee extension iMVC and RFD₂₀₀ were impaired in the affected leg compared to the contralateral leg (p < 0.05) prior to surgery. A significant (Knee extension RFD₂₀₀, p = 0.033) or borderline significant improvement was observed in the affected leg compared to the contralateral leg from before to 12 months after surgery in most variables (leg × time interaction, n.s.).

CONCLUSION

Middle-aged patients undergoing surgery for degenerative medial meniscal tears show significant reductions in muscle strength, rapid force production, and functional performance in the leg undergoing surgery compared to the contralateral leg prior to surgery. These deficits in muscle strength and knee function were still present at 3 months post-surgery but were no longer observed at 12 months following surgery.

LEVEL OF EVIDENCE

III.

The biology of meniscal pathology in osteoarthritis and its contribution to joint disease: beyond simple mechanics

The meniscal cartilages in the knee function to improve congruity of the medial and lateral femoro-tibial joints and play critical roles in load distribution and joint stability. Meniscal tears of various configurations are one of the most common conditions of the knee and are associated with an increased risk of developing osteoarthritis (OA). While this risk has been largely attributed to loss of the biomechanical functions of the menisci, there is accumulating evidence suggesting that other aspects of meniscal biology may play a role in determining the long-term consequences of meniscal damage for joint health. In this narrative review, we examine the existing literature and present some new data implicating synthesis and secretion of enzymes and other pro-catabolic mediators by injured and degenerate menisci, contributing to the pathological change in other knee joint tissues in OA.

Increased risk for knee replacement surgery after arthroscopic surgery for degenerative meniscal tears: a multi-center longitudinal observational study using data from the osteoarthritis initiative

OBJECTIVE

The primary objective was to assess whether patients with knee osteoarthritis and whom undergo arthroscopic meniscectomy have an increased risk for future knee replacement surgery.

DESIGN

Data used were obtained from the Osteoarthritis Initiative (OAI) study.

SETTING

Participants were enrolled, in four clinical centers, between February 2004 and May 2006 and were followed up on an annual basis up to and including 108-months from enrollment.

PARTICIPANTS

4674 participants (58.4% female), aged 45-79, of all ethnic groups, who had, and those who were at high risk for developing, symptomatic knee osteoarthritis were included, of which 3337 (71.4%) were included in the final follow up visit.

MAIN OUTCOME MEASURES

Hazard ratio of knee replacement surgery for participants who underwent arthroscopic meniscectomy during follow up compared to propensity score matched participants who did not undergo arthroscopic meniscectomy during follow up.

RESULTS

335 participants underwent arthroscopic meniscectomy during follow up, of which 63 (18.8%) underwent knee replacement surgery in the same knee. Of the 335 propensity score matched participants 38 (11.1%) underwent knee replacement surgery during follow up. Results from the Cox-proportional hazards model demonstrated that the hazard ratio of knee replacement surgery was 3.03 (95% CI (1.67-5.26)) for participants who underwent arthroscopic meniscectomy relative to the propensity score matched participants who did not undergo arthroscopic meniscectomy.

CONCLUSIONS

In patients with knee osteoarthritis arthroscopic knee surgery with meniscectomy is associated with a three fold increase in the risk for future knee replacement surgery.

Traumatic and Degenerative Meniscus Tears Have Different Gene Expression Signatures

BACKGROUND

Meniscus tears are classified as traumatic or degenerative based on the tear pattern. There is little evidence demonstrating biological differences between the 2 tear types.

HYPOTHESIS

Gene expression signatures in the injured meniscus are different between traumatic (vertical) and degenerative (complex, horizontal, or flap) tears.

STUDY DESIGN

Controlled laboratory study.

METHODS

Samples of the torn meniscus from the white-white zone were removed at the time of clinically indicated partial meniscectomy from 48 patients (37 with degenerative tears and 11 with traumatic tears). mRNA expression in the injured menisci was measured by quantitative real-time polymerase chain reaction for selected molecular markers of osteoarthritis, inflammation, and cartilage homeostasis (eg, cytokines/chemokines, aggrecanases/metalloproteinases, transcription factors, cartilage matrix genes, and adipokines). The tear pattern (traumatic or degenerative) and location (medial or lateral) were recorded for each patient. Gene expression differences between degenerative and traumatic tears were computed after adjusting for patients' age, sex, and body mass index and for location of the resected meniscus (medial/lateral).

RESULTS

Gene expression in meniscus tears varied by pattern. Chemokines ( IL8 [ P < .001] and CXCL6 [ P < .001]) and matrix metalloproteinases ( MMP1 [ P = .011] and MMP3 [ P = .016]) were expressed at a significantly higher level in traumatic tears compared with degenerative tears. In contrast, COL1A1 was expressed at a lower level in traumatic tears compared with degenerative tears ( P = .058). None of the genes tested demonstrated significant differences between medial and lateral meniscus tears.

CONCLUSION

Traumatic meniscus tears overall exhibited a higher inflammatory/catabolic response as evidenced by higher levels of chemokine and matrix metalloproteinase expression than degenerative tears. These findings suggest that there is a (molecular) biological distinction between traumatic and degenerative tears.

CLINICAL RELEVANCE

The catabolic/inflammatory differences between traumatic and degenerative tears may be relevant to treatment decisions regarding the meniscus as well as advance our understanding of how meniscus tears relate to the development of knee osteoarthritis.

Meniscal biology in health and disease

The knee is a fascinating yet complex joint. Researchers and clinicians agree that the joint is an organ comprised of highly specialized intrinsic and extrinsic tissues contributing to both health and disease. Key to the function and movement of the knee are the menisci, exquisite fibrocartilage structures that are critical structures for maintaining biological and biomechanical integrity of the joint. The biological/physiological functions of the menisci must be understood at the tissue, cellular and even molecular levels in order to determine clinically relevant methods for assessing it and influencing it. By investigating normal and pathological functions at the basic science level, we can begin to translate data to patients. The objective of this article is to provide an overview of this translational pathway so that progression toward improved diagnostic, preventative, and therapeutic strategies can be effectively pursued. We have thoroughly examined the pathobiological, biomarker, and imaging aspects of meniscus research. This translational approach can be effective toward optimal diagnosis, prevention, and treatment for the millions of patients who suffer from meniscal disorders each year.

Advanced Imaging in Osteoarthritis

Context:

Radiography is widely accepted as the gold standard for diagnosing osteoarthritis (OA), but it has limitations when assessing early stage OA and monitoring progression. While there are improvements in the treatment of OA, the challenge is early recognition.

Evidence Acquisition:

MEDLINE and PubMed as well as professional orthopaedic and imaging websites were reviewed from 2006 to 2016.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Magnetic resonance imaging (MRI) can provide the most comprehensive assessment of joint injury and OA with the advantages of being noninvasive and multiplanar with excellent soft tissue contrast. However, MRI is expensive, time consuming, and not widely used for monitoring OA clinically. Computed tomography (CT) and CT arthrography (CTA) can also be used to evaluate OA, but these are also invasive and require radiation exposure. Ultrasound is particularly useful for evaluation of synovitis but not for progression of OA.

Conclusion:

MRI, CT, and CTA are available for the diagnosis and monitoring of OA. Improvement in techniques and decrease in cost can allow some of these modalities to be effective methods of detecting early OA.

Context-specific protection of TGFα null mice from osteoarthritis

Transforming growth factor alpha (TGFα) is a growth factor involved in osteoarthritis (OA). TGFα induces an OA-like phenotype in articular chondrocytes, by inhibiting matrix synthesis and promoting catabolic factor expression. To better understand TGFα’s potential as a therapeutic target, we employed two in vivo OA models: (1) post-traumatic and (2) aging related OA. Ten-week old and six-month old male Tgfa null mice and their heterozygous (control) littermates underwent destabilization of the medial meniscus (DMM) surgery. Disease progression was assessed histologically using the Osteoarthritis Research Society International (OARSI) scoring system. As well, spontaneous disease progression was analyzed in eighteen-month-old Tgfa null and heterozygous mice. Ten-week old Tgfa null mice were protected from OA progression at both seven and fourteen weeks post-surgery. No protection was seen however in six-month old null mice after DMM surgery, and no differences were observed between genotypes in the aging model. Thus, young Tgfa null mice are protected from OA progression in the DMM model, while older mice are not. In addition, Tgfa null mice are equally susceptible to spontaneous OA development during aging. Thus, TGFα might be a valuable therapeutic target in some post-traumatic forms of OA, however its role in idiopathic disease is less clear.

Changes in knee joint load indices from before to 12 months after arthroscopic partial meniscectomy: a prospective cohort study

OBJECTIVE

Patients undergoing arthroscopic partial meniscectomy (APM) are at increased risk of knee osteoarthritis (OA). Meniscal damage and/or surgery may alter knee joint loading to increase OA risk. We investigated changes in knee joint loading following medial APM surgery, compared with the contra-lateral leg.

METHODS

We estimated indices of knee joint loading (external peak knee adduction moment (KAM), KAM impulse and peak knee flexion moment (KFM)) normalized to body size (i.e., body mass (BM) and height (HT)) using 3D gait analysis in 23 patients (17 men, mean (SD) 46.2 (6.4) years, BMI 25.8 (3.4) kg/m(2)) without radiographic knee OA before and 12 months after medial APM. Static alignment was assessed by radiography and self-reported outcomes by Knee injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

Peak KAM and KAM impulse increased in the APM leg compared to the contra-lateral leg from before to 12 months after surgery (change difference: 0.38 Nm/BM*HT% 95% CI 0.01 to 0.76 (P = 0.049) and 0.20 Nm*s/BM*HT% 95% CI 0.10 to 0.30 (P < 0.001)). Patients self-reported improvements on all KOOS subscales (KOOS pain improvement: 22.8 95% CI 14.5 to 31.0 (P < 0.01)).

CONCLUSIONS

A relative increase in indices of medial compartment loading was observed in the leg undergoing APM compared with the contra-lateral leg from before to 12 months after surgery. This increase may contribute to the elevated risk of knee OA in these patients. Randomized trials including a non-surgical control group are needed to determine if changes in joint loading following APM are caused by surgery or by changes in symptoms.

A Cohort Study on Meniscal Lesions among Airport Baggage Handlers

Meniscal lesions are common and may contribute to the development of knee arthrosis. A few case-control and cross-sectional studies have identified knee-straining work as risk factors for meniscal lesions, but exposure-response relations and the role of specific exposures are uncertain, and previous results may be sensitive to reporting and selection bias. We examined the relation between meniscal lesions and cumulative exposure to heavy lifting in a prospective register-based study with complete follow-up and independent information on exposure and outcome. We established a cohort of unskilled men employed at Copenhagen Airport or in other companies in the metropolitan Copenhagen area from 1990 to 2012 (the Copenhagen Airport Cohort). The cohort at risk included 3,307 airport baggage handlers with heavy lifting and kneeling or squatting work tasks and 63,934 referents with a similar socioeconomic background and less knee-straining work. Baggage handlers lifted suitcases with an average weight of approximately 15 kg, in total approximately five tonnes during a 9-hour workday. The cohort was followed in the National Patient Register and Civil Registration System. The outcome was a first time hospital diagnosis or surgery of a meniscal lesion. Baggage handlers had a higher incidence of meniscal lesions than the referents. Within baggage handlers spline regression showed that the incidence rate ratio was 1.91 (95% confidence interval: 1.29-2.84) after five years as a baggage handler and then decreased slowly to reach unity after approximately 30 years, adjusted for effects of potential confounders. This relation between baggage handling and meniscal lesions was present for work on the apron which involves lifting in a kneeling or squatting position, but not in the baggage hall, which only involves lifting in standing positions. The results support that long-term heavy lifting in a kneeling or squatting position is a risk factor for the development of symptomatic meniscal lesions.

Accuracy of MRI evaluation of meniscus tears in the setting of ACL injuries

BACKGROUND

Our purpose was to evaluate the diagnostic performance of magnetic resonance imaging (MRI) for the pre-operative detection of meniscus tears requiring operative intervention, and identify factors that determined accuracy of diagnosing meniscus tears, in the setting of anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients who underwent primary ACL reconstruction were retrospectively reviewed. A meniscus tear was classified as requiring treatment if it was debrided or repaired at the time of ACL reconstruction. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of pre-operative MRIs were determined for medial and lateral meniscus tears.

RESULTS

Sensitivity, specificity, PPV, and NPV of MRI were 0.90, 0.75, 0.58, and 0.95 for medial meniscus tears, respectively, and 0.67, 0.81, 0.65, and 0.82 for lateral meniscus tears. MRI-diagnosed medial meniscus tears were associated with a longer time interval between initial injury and imaging compared to ACL tears without concomitant meniscus injury on MRI (p=0.038). Vertical medial meniscus tears were less likely than other tear patterns to require treatment at the time of ACL reconstruction (p=0.03). MRI showed a higher diagnostic performance for lateral meniscus tears when surgery was performed within 30days of imaging.

CONCLUSIONS

This study demonstrates only moderate sensitivity and specificity of pre-operative MRI in the detection of meniscus tears requiring operative treatment in the setting of ACL injury. High rates of false diagnoses were observed, suggesting MRI may not be as accurate in predicting positive or negative meniscus findings at the time of ACL reconstruction as previously reported.

LEVEL OF EVIDENCE

Level III.

Imaging of Osteoarthritis in Geriatric Patients

Imaging of osteoarthritis (OA) in the elderly is gaining importance because of the aging population. It requires knowledge about findings relevant for patient management and others which are abnormal findings, but part of normal aging without relevance for patient management due to lack of clinical symptoms. This review will provide information on what imaging techniques are best used for knee OA and how to systematically assess knee joint structures in order to cover the most common asymptomatic and symptomatic MR findings in OA. We will discuss which findings are typically found in older patients and which are likely to progress to severe pain and disability, finally leading to total joint replacement. The review may aid radiologists and referring clinicians to better understand the evolution of symptomatic OA and the current or future clinical significance of the most common symptomatic and asymptomatic findings.

Osteoarthritis prevention and meniscus regeneration induced by transplantation of mesenchymal stem cell sheet in a rat meniscal defect model

Transplantation of mesenchymal stem cells (MSCs) is a potential therapy for meniscus regeneration. However, when using single cell suspension injection, there is frequently a significant loss of cells, with only a small percentage of cells remaining at the target site. This issue may be solved with the use of MSC sheets. In the present study, we investigated whether the use of MSC sheets were able to regenerate the meniscus effectively in a rat meniscectomized model. The anterior half of the medial meniscus in 10 rats was excised and an MSC sheet was transplanted in the MSC sheet treatment group, while untreated rats served as the control. After 4 and 8 weeks, the knee joints were examined by gross and histological observation. Histological observation revealed that the anterior portion of meniscus was similar to the native tissue, showing typical fibrochondrocytes surrounded by richer extracellular matrix in the MSC sheet group. In addition, predominant collagen-rich matrix bridging the interface was observed and the neo-meniscus integrated well with its host meniscus. Furthermore, degenerative changes of tibial plateau and femoral condyle occurred in the two groups. MSC sheet transplantation alleviated the degenerative changes efficiently. In conclusion, transplantation of MSC sheets may efficiently promote meniscus regeneration, as well as inhibit the progression of osteoarthritis in knee joints.

Tissue adhesives for meniscus tear repair: an overview of current advances and prospects for future clinical solutions

Menisci are crucial structures in the knee joint as they play important functions in load transfer, maintaining joint stability and in homeostasis of articular cartilage. Unfortunately, ones of the most frequently occurring knee injuries are meniscal tears. Particularly tears in the avascular zone of the meniscus usually do not heal spontaneously and lead to pain, swelling and locking of the knee joint. Eventually, after a (partial) meniscectomy, they will lead to osteoarthritis. Current treatment modalities to repair tears and by that restore the integrity of the native meniscus still carry their drawbacks and a new robust solution is desired. A strong tissue adhesive could provide such a solution and could potentially improve on sutures, which are the current gold standard. Moreover, a glue could serve as a carrier for biological compounds known to enhance tissue healing. Only few tissue adhesives, e.g., Dermabond(®) and fibrin glue, are already successfully used in clinical practice for other applications, but are not considered suitable for gluing meniscus tissue due to their sub-optimal mechanical properties or toxicity. There is a growing interest and research field focusing on the development of novel polymer-based tissue adhesives, but up to now, there is no material specially designed for the repair of meniscal tears. In this review, we discuss the current clinical gold standard treatment of meniscal tears and present an overview of new developments in this field. Moreover, we discuss the properties of different tissue adhesives for their potential use in meniscal tear repair. Finally, we formulate recommendations regarding the design criteria of material properties and adhesive strength for clinically applicable glues for meniscal tears.

Partial meniscectomy is associated with increased risk of incident radiographic osteoarthritis and worsening cartilage damage in the following year

OBJECTIVES

To assess whether partial meniscectomy is associated with increased risk of radiographic osteoarthritis (ROA) and worsening cartilage damage in the following year.

METHODS

We studied 355 knees from the Osteoarthritis Initiative that developed ROA (Kellgren-Lawrence grade ≥ 2), which were matched with control knees. The MR images were assessed using the semi-quantitative MOAKS system. Conditional logistic regression was applied to estimate risk of incident ROA. Logistic regression was used to assess the risk of worsening cartilage damage in knees with partial meniscectomy that developed ROA.

RESULTS

In the group with incident ROA, 4.4 % underwent partial meniscectomy during the year prior to the case-defining visit, compared with none of the knees that did not develop ROA. All (n = 31) knees that had partial meniscectomy and 58.9 % (n = 165) of the knees with prevalent meniscal damage developed ROA (OR = 2.51, 95 % CI [1.73, 3.64]). In knees that developed ROA, partial meniscectomy was associated with an increased risk of worsening cartilage damage (OR = 4.51, 95 % CI [1.53, 13.33]).

CONCLUSIONS

The probability of having had partial meniscectomy was higher in knees that developed ROA. When looking only at knees that developed ROA, partial meniscectomy was associated with greater risk of worsening cartilage damage.

KEY POINTS

• Partial meniscectomy is a controversial treatment option for degenerative meniscal tears. • Partial meniscectomy is strongly associated with incident osteoarthritis within 1 year. • Partial meniscectomy is associated with increased risk of worsening cartilage damage.

Association of MRI findings and expert diagnosis of symptomatic meniscal tear among middle-aged and older adults with knee pain

Background

Our aim was to examine the association between an expert clinician’s impression of symptomatic meniscal tears and subsequent MRI in the context of middle-aged and older adults with knee pain.

Methods

Patients older than 45 were eligible for this IRB-approved substudy if they had knee pain, had not undergone MRI and saw one of two orthopaedic surgeons experienced in the diagnosis of meniscal tear. The surgeon rated their confidence that the patient’s symptoms were due to meniscal tear. The patient subsequently had a 1.5 or 3.0 T MRI within 6 months. We examined the association between presence of meniscal tear on MRI and the surgeon’s confidence that the knee pain was due to meniscal tear using a χ² test for trend.

Results

Of 84 eligible patients, 63 % were female, with a mean age of 64 years and a mean BMI of 27. The surgeon was confident that symptoms emanated from a tear among 39 %. The prevalence of meniscal tear on MRI overall was 74 %. Among subjects whose surgeon indicated high confidence that symptoms were due to meniscal tear, the prevalence was 80 % (95 % CI 63–90 %). Similarly, the prevalence was 87 % (95 % CI 62–96 %) among those whose surgeon had medium confidence and 64 % (95 % CI 48–77 %) among those whose surgeon had low confidence (p = 0.12).

Conclusion

Meniscal tears were frequently found on MRI even when an expert clinician was confident that a patient’s knee symptoms were not due to a meniscal tear, indicating that providers should use MRI sparingly and cautiously to confirm or rule out the attribution of knee pain to meniscal tear.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1010-2) contains supplementary material, which is available to authorized users.

Microstructural heterogeneity directs micromechanics and mechanobiology in native and engineered fibrocartilage

Treatment strategies to address pathologies of fibrocartilaginous tissue are in part limited by an incomplete understanding of structure-function relationships in these load-bearing tissues. There is therefore a pressing need to develop micro-engineered tissue platforms that can recreate the highly inhomogeneous tissue microstructures that are known to influence mechanotransductive processes in normal and diseased tissue. Here, we report the quantification of proteoglycan-rich microdomains in developing, ageing and diseased fibrocartilaginous tissues, and the impact of these microdomains on endogenous cell responses to physiologic deformation within a native-tissue context. We also developed a method to generate heterogeneous tissue-engineered constructs (hetTECs) with non-fibrous proteoglycan-rich microdomains engineered into the fibrous structure, and show that these hetTECs match the microstructural, micromechanical and mechanobiological benchmarks of native tissue. Our tissue-engineered platform should facilitate the study of the mechanobiology of developing, homeostatic, degenerating and regenerating fibrous tissues.

Synovial mesenchymal stem cells promote meniscus regeneration augmented by an autologous Achilles tendon graft in a rat partial meniscus defect model

Although meniscus defects and degeneration are strongly correlated with the later development of osteoarthritis, the promise of regenerative medicine strategies is to prevent and/or delay the disease's progression. Meniscal reconstruction has been shown in animal models with tendon grafting and transplantation of mesenchymal stem cells (MSCs); however, these procedures have not shown the same efficacy in clinical studies. Here, our aim was to investigate the ability of tendon grafts pretreated with exogenous synovial-derived MSCs to prevent cartilage degeneration in a rat partial meniscus defect model. We removed the anterior half of the medial meniscus and grafted autologous Achilles tendons with or without a 10-minute pretreatment of the tendon with synovial MSCs. The meniscus and surrounding cartilage were evaluated at 2, 4, and 8 weeks (n = 5). Tendon grafts increased meniscus size irrespective of synovial MSCs. Histological scores for regenerated menisci were better in the tendon + MSC group than in the other two groups at 4 and 8 weeks. Both macroscopic and histological scores for articular cartilage were significantly better in the tendon + MSC group at 8 weeks. Implanted synovial MSCs survived around the grafted tendon and native meniscus integration site by cell tracking assays with luciferase+, LacZ+, DiI+, and/or GFP+ synovial MSCs and/or GFP+ tendons. Flow cytometric analysis showed that transplanted synovial MSCs retained their MSC properties at 7 days and host synovial tissue also contained cells with MSC characteristics. Synovial MSCs promoted meniscus regeneration augmented by autologous Achilles tendon grafts and prevented cartilage degeneration in rats. Stem Cells2015;33:1927–1938

Cost-effectiveness analysis of arthroscopic surgery compared with non-operative management for osteoarthritis of the knee

OBJECTIVE

To determine the cost-effectiveness of arthroscopic surgery in addition to non-operative treatments compared with non-operative treatments alone in patients with knee osteoarthritis (OA).

DESIGN, SETTING AND PARTICIPANTS

We conducted an economic evaluation alongside a single-centre, randomised trial among patients with symptomatic, radiographic knee OA (KL grade ≥ 2).

INTERVENTIONS

Patients received arthroscopic debridement and partial resection of degenerative knee tissues in addition to optimised non-operative therapy, or optimised non-operative therapy only.

MAIN OUTCOME MEASURES

Direct and indirect costs were collected prospectively over the 2-year study period. The effectiveness outcomes were the Western Ontario McMaster Osteoarthritis Index (WOMAC) and quality-adjusted life years (QALYs). Cost-effectiveness was estimated using the net benefit regression framework considering a range of willingness-to-pay values from the Canadian public payer and societal perspectives. We calculated incremental cost-effectiveness ratios and conducted sensitivity analyses using the extremes of the 95% CIs surrounding mean differences in effect between groups.

RESULTS

168 patients were included. Patients allocated to arthroscopy received partial resection and debridement of degenerative meniscal tears (81%) and/or articular cartilage (97%). There were no significant differences between groups in use of non-operative treatments. The incremental net benefit was negative for all willingness-to-pay values. Uncertainty estimates suggest that even if willing to pay $400,000 to achieve a clinically important improvement in WOMAC score, or ≥$50,000 for an additional QALY, there is <20% probability that the addition of arthroscopy is cost-effective compared with non-operative therapies only. Our sensitivity analysis suggests that even when assuming the largest treatment effect, the addition of arthroscopic surgery is not economically attractive compared with non-operative treatments only.

CONCLUSIONS

Arthroscopic debridement of degenerative articular cartilage and resection of degenerative meniscal tears in addition to non-operative treatments for knee OA is not an economically attractive treatment option compared with non-operative treatment only, regardless of willingness-to-pay value.

TRIAL REGISTRATION NUMBER

NCT00158431.

Transport of Iodine Is Different in Cartilage and Meniscus

Contrast enhanced computed tomography (CECT) has been proposed for diagnostics of cartilage and meniscus injuries and degeneration. As both tissues may be imaged simultaneously, CECT could provide a method for comprehensive evaluation of knee joint health. Since the composition and structure of cartilage and meniscus are different, we hypothesize that transport characteristics of anionic contrast agents also differ between the tissues. This would affect interpretation of CECT images and warrants investigation. To clarify this, we aimed to determine the transport kinematics of anionic iodine (q = -1, M = 126.9 g/mol), assumed to not be significantly affected by the steric hindrance, thus providing faster transport than large molecule contrast agents (e.g., ioxaglate). Cylindrical samples (d = 6 mm, h = 2 mm) were prepared from healthy bovine (n = 10) patella and meniscus, immersed in isotonic phosphate-buffered NaI solution (20 mgI/mL), and subsequently imaged with a micro-CT at 20 time points up to 23 h. Subsequently, normalized attenuation and contrast agent flux, as well as water, collagen, and proteoglycan (PG) contents in the tissues were determined. Normalized attenuation at equilibrium was higher (p = 0.005) in meniscus. Contrast agent flux was lower (p = 0.005) in the meniscus at 10 min, but higher (p < 0.05) between 30 and 120 min. In both tissues, contrast agent distribution at equilibrium suggested an inverse agreement with the depth-wise PG distribution. In conclusion, iodine transport into cartilage and meniscus was different, especially between the first 2 hours after the immersion. This is an important finding which should be considered during simultaneous CECT of cartilage and meniscus.

A comparison of stress in cracked fibrous tissue specimens with varied crack location, loading, and orientation using finite element analysis

Cracks in fibrous soft tissue, such as intervertebral disc annulus fibrosus and knee meniscus, cause pain and compromise joint mechanics. A crack concentrates stress at its tip, making further failure and crack extension (fracture) more likely. Ex vivo mechanical testing is an important tool for studying the loading conditions required for crack extension, but prior work has shown that it is difficult to reproduce crack extension. Most prior work used edge crack specimens in uniaxial tension, with the crack 90° to the edge of the specimen. This configuration does not necessarily represent the loading conditions that cause in vivo crack extension. To find a potentially better choice for experiments aiming to reproduce crack extension, we used finite element analysis to compare, in factorial combination, (1) center crack vs. edge crack location, (2) biaxial vs. uniaxial loading, and (3) crack-fiber angles ranging from 0° to 90°. The simulated material was annulus fibrosus fibrocartilage with a single fiber family. We hypothesized that one of the simulated test cases would produce a stronger stress concentration than the commonly used uniaxially loaded 90° crack-fiber angle edge crack case. Stress concentrations were compared between cases in terms of fiber-parallel stress (representing risk of fiber rupture), fiber-perpendicular stress (representing risk of matrix rupture), and fiber shear stress (representing risk of fiber sliding). Fiber-perpendicular stress and fiber shear stress concentrations were greatest in edge crack specimens (of any crack-fiber angle) and center crack specimens with a 90° crack-fiber angle. However, unless the crack is parallel to the fiber direction, these stress components alone are insufficient to cause crack opening and extension. Fiber-parallel stress concentrations were greatest in center crack specimens with a 45° crack-fiber angle, either biaxially or uniaxially loaded. We therefore recommend that the 45° center crack case be tried in future experiments intended to study crack extension by fiber rupture.

Analysis of short and long-term results of horizontal meniscal tears in young adults

INTRODUCTION

Symptomatic horizontal meniscal tears are rare but worrisome lesions in young adults. These are overuse injuries not amenable to the classic arthroscopic sutures. An open meniscal repair allows the meniscal lesion to be suture vertically, perpendicular to its in the vascularized zone. The purpose of this study was to evaluate the short and long-term clinical and radiological outcomes of the aforementioned surgical technique.

MATERIAL AND METHOD

The first cohort consisted of 24 patients operated between 2009 and 2011 (6 women, 18 men; mean age 26years) having 11 lateral and 13 medial meniscal tears. The second cohort was of 10 patients operated between 2001 and 2002 (3 women, 7 men; mean age 24years) having 8 lateral and 2 medial meniscal tears. Patients were reviewed at the last follow-up using the IKDC, Lysholm and KOOS scores. Patients in the first cohort had an MRI, while those in the second cohort had X-rays.

RESULTS

Eighteen patients in the first cohort were reviewed with a mean follow-up of 2 years (12-45 months) and 9 patients from the second cohort were reviewed after 10years (97-142 months). In the first cohort, one patient required secondary menisectomy. The mean Lysholm score was 90 and the subjective IKDC was 85. Every MRI examination found reduced extent and intensity of the hyperintense signal. In the second cohort, no patients required secondary meniscectomy. Two patients had joint space narrowing (less than 50%) on radiographs. The mean Lysholm score was 99 and the subjective IKDC was 91.

CONCLUSION

Open repair of horizontal meniscal tears in young adults leads to good subjective and objective results in the short term, which are maintained in the long-term.

LEVEL OF EVIDENCE

Level IV - retrospective study.

What comes first? Multitissue involvement leading to radiographic osteoarthritis: magnetic resonance imaging-based trajectory analysis over four years in the osteoarthritis initiative

OBJECTIVE

To assess whether the presence of structural osteoarthritis (OA) features over as many as 4 years prior to incident radiographic OA increases the risk of radiographic OA in a nested, case-control design.

METHODS

We studied 355 knees from the Osteoarthritis Initiative cohort that developed radiographic OA before the 48-month visit. They were matched one-to-one by sex, age, and contralateral knee radiographic status with a control knee. Magnetic resonance images (MRIs) were read for bone marrow lesions (BMLs), cartilage damage, meniscal damage (including tears and extrusion), Hoffa synovitis, and effusion synovitis. Conditional logistic regression was applied to assess the risk of radiographic OA with regard to the presence of BMLs (score ≥2), cartilage lesions (score ≥1.1), meniscal damage (any) and extrusion of ≥3 mm ± (score ≥2), and Hoffa and effusion synovitis (any). Time points were defined as incident radiographic OA visit (P0), 1 year prior to the detection of radiographic OA (P -1), 2 years prior to the detection of radiographic OA (P -2), etc.

RESULTS

The presence of Hoffa synovitis (hazard ratio [HR] 1.76 [95% confidence interval (95% CI) 1.18-2.64]), effusion synovitis (HR 1.81 [95% CI 1.18-2.78]), and medial meniscal damage (HR 1.83 [95% CI 1.17-2.89]) at P -2 predicted radiographic OA incidence. At P -1, all features but meniscal extrusion predicted radiographic OA, with highest odds for medial BMLs (HR 6.50 [95% CI 2.27-18.62]) and effusion synovitis (HR 2.50 [95% CI 1.76-3.54]). The findings at P -3 and P -4 did not reach statistical significance.

CONCLUSION

Our findings indicate that the presence of specific structural features of MRI-detected joint damage 2 years prior to incident radiographic OA increases the risk of incident radiographic OA. However, 1 year prior to radiographic OA, the presence of almost any abnormal morphologic feature increases the risk of radiographic OA in the subsequent year.

Meniscus suture repair: minimum 10-year outcomes in patients younger than 40 years compared with patients 40 and older

BACKGROUND

Few studies have compared outcomes after meniscus suture repair in patients younger than 40 years versus patients 40 years and older.

PURPOSE

To document failure rates and long-term outcomes after meniscus suture repair by a single surgeon, using the inside-out technique, at a minimum 10-year follow-up in patients younger than 40 years versus those 40 years and older.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study included all patients 18 years or older who underwent meniscus suture repair with the inside-out technique by a single surgeon between January 1992 and December 2003. Patients were divided into 2 cohorts according to age: <40 years (cohort 1) and ≥40 years (cohort 2). If patients underwent subsequent knee surgery, all subsequent reports, whether performed by the original treating surgeon or by a different surgeon elsewhere, were reviewed by 2 independent reviewers not involved in the primary care of the patients. Reviewers classified surgeries as failures if the subsequent surgery treated the same area of the meniscus as repaired in the index surgery. Patients completed a subjective questionnaire at minimum of 10 years after arthroscopy. Outcomes measures included Lysholm, Tegner, and patient satisfaction with outcome. All data were collected prospectively.

RESULTS

The surgeon performed 339 meniscus repairs between 1992 and 2003. The study included 181 knees in 178 patients, who had a mean age of 33 years (range, 18-70 years). Cohort 1 contained 136 knees; 16 patients (12%) were lost to follow-up and 47 (35%) underwent a subsequent knee arthroscopy. Cohort 2 contained 45 knees; 2 patients (4.4%) were lost to follow-up, 3 patients had a total knee arthroplasty, and 12 patients (28%) underwent a subsequent knee arthroscopy. In cohort 1, the meniscus repair failure rate was 5.5% (6/110), and in cohort 2 it was 5.3% (2/38) (P = .927). There was no significant difference in failure rate based on which meniscus was repaired (P = .257), concomitant anterior cruciate ligament (ACL) reconstruction (P = .092), or microfracture (P = .674). Average follow-up time for cohort 1 was 16.1 years (range, 10.0-21.9 years), with 82% follow-up (n = 73/89); average follow-up time for cohort 2 was 16.2 years (range, 10.1-21.0 years), with 93% follow-up (n = 28/30). There were no significant differences in outcomes scores after meniscus suture repair based on age cohort or meniscus side, presence of an ACL tear, or concomitant microfracture procedure.

CONCLUSION

Meniscus repair failure rate was not different in patients who were younger than 40 years versus those who were 40 years or older at time of meniscus index surgery. Patients who underwent meniscus suture repair had high function and high patient satisfaction at an average of 16 years after meniscus suture repair, and no differences were seen based on age.

Detecting Meniscal Tears in Primary Care: Reproducibility and Accuracy of 2 Weight-Bearing Tests and 1 Non-Weight-Bearing Test

STUDY DESIGN

Diagnostic accuracy study using a cross-sectional design.

OBJECTIVES

To determine the interexaminer reliability and the diagnostic accuracy in primary care of 1 existing weight-bearing meniscal test, the Thessaly test, 1 new weight-bearing test, the deep squat test, and 1 non-weight-bearing test, the joint-line tenderness test.

BACKGROUND

Meniscal tears are difficult to detect in primary care. Although valuable in secondary care, weight-bearing physical examination tests require validation in primary care in unselected patients.

METHODS

Between October 2009 and December 2013, 121 patients (age range, 18-65 years) seen in primary care and suspected of having internal derangement of the knee of less than 6 months in duration were included in the study. Diagnostic accuracy of the 3 meniscal tests was determined based on assessment with magnetic resonance imaging. The meniscal tests were performed by 3 trained physical therapists, who were not informed about the patient history and magnetic resonance imaging results. Each test was performed independently by 2 of the 3 trained physical therapists in alternating pairs.

RESULTS

The Thessaly test and the deep squat test had a moderate level of interexaminer reliability, with kappas of 0.54 and 0.46, respectively. The joint-line tenderness test had poor interexaminer reliability and was therefore not assessed for diagnostic accuracy. The following results are reported separately for both examiners. The Thessaly test had a sensitivity of 66.7% (95% confidence interval [CI]: 53.0%, 78.0%) and 51.2% (95% CI: 36.8%, 65.4%), a specificity of 37.9% (95% CI: 27.2%, 50.0%) and 43.5% (95% CI: 30.2%, 57.8%), a positive likelihood ratio of 1.07 (95% CI: 0.82, 1.41) and 0.91 (95% CI: 0.62, 1.33), and a negative likelihood ratio of 0.88 (95% CI: 0.54, 1.45) and 1.12 (95% CI: 0.72, 1.76). Similarly, the deep squat test had a sensitivity of 74.5% (95% CI: 61.1%, 84.5%) and 76.7% (95% CI: 62.3%, 86.9%), a specificity of 42.4% (95% CI: 31.2%, 54.4%) and 36.2% (95% CI: 24.0%, 50.5%), a positive likelihood ratio of 1.29 (95% CI: 0.97, 1.68) and 1.20 (95% CI: 0.92, 1.58), and a negative likelihood ratio of 0.60 (95% CI: 0.35, 1.04) and 0.64 (95% CI: 0.33, 1.25).

CONCLUSION

Although the Thessaly and deep squat tests have a moderate level of reliability, neither test is sufficiently accurate to help in the diagnosis of meniscal tears in primary care. Future research should focus on other relevant patient variables instead of on physical examination tests in the detection of meniscal tears.

LEVEL OF EVIDENCE

Diagnosis, level 3b.