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)

Younger age, longer delay to surgery and meniscal tears are associated with a smaller ACL remnant: An analysis from the registry of the Francophone Arthroscopic Society

PURPOSE

This study aimed to evaluate which preoperative patient, injury or clinical factors were associated with the anterior cruciate ligament (ACL) remnant volume in patients undergoing ACL surgery. It was hypothesized that the main factors determining an insufficient ACL remnant volume at the time of surgery were younger age and longer time to surgery.

METHODS

A retrospective analysis from the Francophone Arthroscopic Society's registry was conducted, including 1565 patients with an ACL lesion underdoing a primary ACL surgery (reconstruction or repair) between June 2020 and June 2023. Patients were excluded in case of revision surgery and incomplete data. Preoperative factors-including patient demographics, delay to surgery, preoperative laxity and the presence of meniscal tears or cartilage lesions-were analysed to determine their influence on ACL remnant volume (estimated by the surgeon as the percentage of residual volume). Univariate, multivariate and receiver operating characteristic curve analyses were performed to explore these relationships.

RESULTS

Multivariate analyses demonstrated that younger age (<20 years and 20-30 years compared to ≥40, p = 0.02), higher time from injury to surgery (≥12 months compared to <3 months, p = 0.01) and the presence of a medial (p = 0.01) or a lateral meniscal tear (p = 0.02) were significant predictors of an ACL remnant volume ≤ 50%.

CONCLUSIONS

Younger age (under 30 years of age), a time from injury to surgery above 12 months and the presence of medial and lateral meniscal tears are associated with higher odds of observing a smaller ACL remnant volume at the time of the ACL surgery. These factors should be considered when planning ACL remnant preservation techniques.

LEVEL OF EVIDENCE

Level III.

Medial meniscus injury changed plantar pressure distributions and decreased posture stability especially in those with varus alignment: a cross-sectional study based on a wearable smart plantar pressure system

BACKGROUND

Medial meniscus (MM) injuries are common and often contribute to knee osteoarthritis (KOA). While studies focus on joint degeneration, the role of extrinsic factors such as postural control remains underexplored. This study investigated how MM injuries affected postural control, particularly plantar pressure distribution, with an emphasis on lower limb alignment.

METHODS

83 participants were recruited: 29 healthy subjects, 29 MM patients with neutral alignment (-3°< hip-knee-ankle angle (HKA) ≤ 3°), and 25 MM patients with varus alignment (HKA > 3°). Plantar pressure was measured using a shoe-integrated detection system. Normalized peak force, center-of-pressure (COP), and time-to-boundary (TTB) were measured during walking and single-leg stance (SLS).

RESULTS

During walking, compared to the healthy group, the varus alignment group showed lower peak force for the posterior heel (P = 0.012), lateral midfoot (P = 0.024) and hallux (P = 0.009). When the two sides were compared, the varus group exhibited a lower peak force in the anterior heel (P = 0.004) and hallux (P = 0.017) of the affected sides, the neutral (P = 0.043) and varus (P = 0.045) groups all showed higher medio-lateral COP of the unaffected sides, indicating the COP shifting laterally. In SLS test, the two MM groups demonstrated increased peak force of the third (P = 0.037) and fifth (P = 0.040) metatarsals compared to the healthy group, the peak force of the posterior heel were lower in the varus alignment group compared to the healthy group (P = 0.007) and the neutral alignment group (P = 0.008). And the TTB absolute value of medial-lateral direction of the two MM groups were lower than healthy controls (P = 0.029). The area under the receiver operating characteristic curve (AUC = 0.698, P = 0.016) suggested that peak force of posterior heel had good performance to discriminate varus alignment group from neutral alignment group.

CONCLUSION

MM injuries, especially with varus alignment, lead to significant changes in plantar pressure distribution and postural stability. These insights are clinically significant for designing early, biomechanically-informed rehabilitative strategies to optimize recovery and prevent further joint degeneration following MM injuries.

Halving of the meniscectomy rate and their costs in Italy: A 15-years period analysis

PURPOSE

The purpose of this study was to determine the incidence and hospitalization trends of meniscectomy in Italy from 2001 to 2016. A secondary aim was to investigate the economic burden of the disease on the national healthcare system.

METHODS

Data were extracted from the Italian Ministry of Health's National Hospital Discharge Reports. Diagnoses are coded according to the ICD-9-CM. Meniscectomy was defined by the following main procedure codes: 806, 8026 and 8145. By dividing the number of annual cases by the size of the adult population reported annually by ISTAT, incidence rates were computed.

RESULTS

Overall, 1,454,891 meniscectomies were performed in the study period between 2001 and 2016. The incidence was 178 procedures for every 100,000 Italian inhabitants. The incidence declined from 202 in 2001 to 106 in 2016. Males were the largest portion of patients undergoing surgery (68.2%). The average age of patients was 46.59 ± 15.07. A decreasing trend in length of hospital stay was observed over the study period. The annual average cost per 100,000 inhabitants was EUR 491.219 ± 122.148 with a range from EUR 291,500 ± 79.500 in 2016 to EUR 610,500 ± 166.500 in 2004.

CONCLUSION

In Italy, the number of meniscectomies performed in the adult population has almost halved over the study period. Results of the present study in the Italian population seem to reflect how the clinical evidence basis affects surgical technique selection. The economic burden of meniscectomy is relevant in Italy with an estimated expenditure from EUR 181.861.375 to 318.257.406 between 2001 and 2016.

LEVEL OF EVIDENCE

Level III.

The applied study to improve the treatment of knee sports injuries in ultimate frisbee players based on personalized exercise prescription: a randomized controlled trial

Objective

Ultimate frisbee can lead to severe sports injuries, especially joint injuries in the lower limbs, such as knee meniscus injuries. This study examines the impact of personalized exercise therapy on knee meniscus injuries in ultimate frisbee players in the Lingnan region of China.

Methods

Seventy-six patients with confirmed meniscal injuries participated in the study, divided into an intervention group (n = 38) and a control group (n = 38). The control group received standard treatment, including drug therapy and physical therapy. The intervention group received standard treatment plus a personalized exercise regimen based on FITT-VP (frequency, intensity, time, type, volume, and progression) principles, incorporating strength training, aerobic exercise, flexibility training, neuromuscular training, and aquatic exercise. This program was monitored and adjusted over a six-month period through both online and offline methods. The primary outcomes were joint range of motion (ROM), thigh circumference atrophy index (TCAI), Lysholm Rating Scale (LRS) scores, and visual analog scores (VAS). The secondary outcome was the International Knee Documentation Committee (IKDC) score. Data were collected before the intervention, and at 1 month and 6 months after the intervention. Statistical analysis was conducted using SPSS 24.0 and GraphPad 10.0, with a significance level set at α = 0.05.

Results

After 1 month, the intervention group showed significantly better results in ROM (116.67 ± 9.063), LRS score (86.316 ± 3.750), and IKDC score (80.473 ± 5.421) compared to the control group (111.784 ± 4.778, 82.579 ± 3.818, and 77.684 ± 4.430, respectively) (p < 0.05). The TCAI (3.219 ± 1.889) and VAS score (1.921 ± 0.673) in the intervention group were significantly lower than those in the control group (5.228 ± 2.131 and 2.710 ± 1.112, respectively) (p < 0.01). After 6 months, the differences in LRS and VAS scores between the groups were not significant. However, the intervention group continued to show significant improvements in ROM (134.934 ± 3.011), TCAI (1.107 ± 1.158), and IKDC score (93.315 ± 1.847) compared to the control group (125.395 ± 18.554, 4.574 ± 1.109, and 87.789 ± 4.437, respectively) (p < 0.05).

Conclusion

Personalized exercise prescriptions offer significant therapeutic and rehabilitative benefits for ultimate frisbee players with knee meniscus injuries. This approach helps to reduce symptoms, alleviate pain, and improve joint function, muscle strength, and athletic performance after sports-related injuries.

Prediction model for tibial plateau fracture combined with meniscus injury

PURPOSE

To investigate a prediction model of meniscus injury in patients with tibial plateau fracture.

METHODS

This retrospective study enrolled patients with tibial plateau fractures who were treated in the Third Hospital of Hebei Medical University from January 1, 2015, to June 30, 2022. Patients were divided into a development cohort and a validation cohort based on the time-lapse validation method. Patients in each cohort were divided into a group with meniscus injury and a group without meniscus injury. Statistical analysis with Student's t-test for continuous variables and chi square test for categorical variables was performed for patients with and without meniscus injury in the development cohort. Multivariate logistic regression analysis was used to screen the risk factors of tibial plateau combined with meniscal injury, and a clinical prediction model was constructed. Model performance was measured by examining discrimination (Harrell's C-index), calibration (calibration plots), and utility [decision analysis curves (DCA)]. The model was validated internally using bootstrapping and externally by calculating their performance in a validation cohort.

RESULTS

Five hundred patients (313 [62.6%] males, 187 [37.4%] females) with a mean age of 47.7 ± 13.8 years were eligible and were divided into development (n = 262) and validation (n = 238) cohorts. A total of 284 patients had meniscus injury, including 136 in the development cohort and 148 in the validation cohort We identified high-energy injuries as a risk factor (OR = 1.969, 95%CI 1.131-3.427). Compared with blood type A, patients with blood type B were more likely to experience tibial plateau fracture with meniscus injury (OR = 2.967, 95%CI 1.531-5.748), and office work was a protective factor (OR = 0.279, 95%CI 0.126-0.618). The C-index of the overall survival model was 0.687 (95% CI, 0.623-0.751). Similar C-indices were obtained for external validation [0.700(0.631-0.768)] and internal validation [0.639 (0.638-0.643)]. The model was adequately calibrated and its predictions correlated with the observed outcomes. The DCA curve showed that the model had the best clinical validity when the threshold probability was 0.40 and 0.82.

CONCLUSIONS

Patients with blood type B and high-energy injuries are more likely to have meniscal injury. This may help in clinical trial design and individual clinical decision-making.

Diagnosis, prevention and treatment of common shoulder injuries in sport: grading the evidence - a statement paper commissioned by the Danish Society of Sports Physical Therapy (DSSF)

This statement paper summarises and appraises the evidence on diagnosis, prevention, and treatment of common shoulder injuries in sports. We systematically searched Medline and Embase. The Grading of Recommendations Assessment, Development and Evaluation tool was applied to evaluate the overall quality of evidence.For diagnosis, we included 19 clinical tests from mixed populations. Tests for anterior instability, biceps-labrum complex injuries and full subscapularis rupture had high diagnostic accuracy (low to moderate quality of evidence).For prevention, the Oslo Sports Trauma Research Center, the Shoulder Control, the FIFA 11+ shoulder injury prevention programmes, and a baseball-specific programme (range of motion, stretching, dynamic stability and strengthening exercises) showed moderate to large effect size in reducing the risk of shoulder injury compared with no intervention (very low to moderate quality of evidence).For treatment, a rehabilitation programme including stretching, ice packs, electrotherapy and compression, and strengthening exercises showed a large effect size in reducing pain and disability compared with no intervention in athletes with subacromial impingement syndrome (very low to moderate quality of evidence). For the treatment of supraspinatus tendinopathy, hyperthermia treatment (heating the skin to 38°C-40°C) resulted in large effect size in reducing pain and disability compared with ultrasound or pendular swinging and stretching exercises (moderate quality of evidence). Strengthening exercise alone or in combination with stretching exercises promoted a large effect in reducing shoulder pain (cohort studies, no comparators) (very low quality of evidence). The quality of evidence for most estimates was low to moderate, indicating that future high-quality research may alter our recommendations for clinical practice.

Variation in Patient-Reported Outcomes in Young and Old Patients Up to 4 to 6 Years After Arthroscopic Partial Meniscectomy

OBJECTIVE

To assess the variation in changes in patient-reported outcomes 4 to 6 years after arthroscopic partial meniscectomy (APM).

DESIGN

Prospective cohort study.

SETTING

Orthopedic departments at public hospitals.

PATIENTS

Patients (n = 447) from the Knee Arthroscopy Cohort Southern Denmark undergoing APM.

INTERVENTIONS

All patients underwent APM.

MAIN OUTCOME MEASURES

Change in KOOS4 scores from baseline before surgery to ∼5 years (range 4-6 years) after surgery. KOOS4 is the average aggregated score of 4 of 5 of the Knee injury and Osteoarthritis Outcome Score (KOOS) excluding the activities of daily living subscale (minimal clinical important improvement ∼10 points). A mixed linear model adjusted for sex and body mass index was used to assess change from baseline to ∼5-year follow-up. Change in KOOS4 was divided into 5 categories based on change from baseline to ∼5-year follow-up: <0 points, 0 to 9 points, 10 to 19 points, 20 to 29 points, and ≥30 points.

RESULTS

On average, patient-reported outcomes continued to improve from baseline to ∼5-year follow-up (mean KOOS4 change: 26, 95% CI, 24-28). Proportions in the different response groups were <0 points (12%), 0 to 9 points (13%), 10 to 19 points (16%), 20 to 29 points (19%), and ≥30 points (40%), with no difference between younger (≤40 years, n = 75) and older (>40 years, n = 337) patients (P = 0.898).

CONCLUSIONS

Patient-reported outcomes on average improved up to ∼5 years after APM; however, large variability was observed. The similar variability in younger and older patients questions the assumption that younger patients with traumatic injuries experience larger benefits from APM.

Effectiveness of exercise versus arthroscopic partial meniscectomy plus exercise in the management of degenerative meniscal tears at 5-year follow-up: a systematic review and meta-analysis

INTRODUCTION

There are no meta-analytical data in the long term for comparing surgery and exercise for meniscal tear. The aim of this study is to compare the effectiveness of exercise versus arthroscopic partial meniscectomy (APM) plus exercise for degenerative meniscal tears (DMT) in knee function at 5-year follow-up.

MATERIALS AND METHODS

A systematic search of Medline, EMBASE, Web of Science, SciELO, SPORTDiscus, Scopus, and Cochrane Library was performed. The studies were included if they were randomized controlled trials performed in patients aged ≥ 18 years with DMT, that compared physical therapy to APM at 5-year follow-up, and reported at least one outcome measure of knee function/disability. Risk of bias was analyzed with the Cochrane RoB-2 tool and certainty of evidence with GRADE recommendations. A random effects model meta-analysis was performed.

RESULTS

3743 articles were identified and 4 met the criteria. Three had low risk of bias and one had some concerns. There were no significant between-group differences, in within-group changes from baseline to 5-year, on the Knee Injury and Osteoarthritis Outcome Score pain (- 2.28; 95% CI - 5.41 to 0.84), symptoms (- 0.24; 95% CI - 4.13 to 3.64), activities of daily living (- 2.16; 95% CI - 6.16 to 1.83) and quality of life (- 3.98; 95% CI - 9.05 to 1.10). There was a significant difference in support of APM plus exercise for sport/recreation (- 9.28; 95% CI - 18.28 to - 0.29). Leave-one-out sensitivity analysis revealed a non-significant difference in sport/recreation (- 5.05; 95% CI - 12.04 to 1.94). There were no differences in other patient-reported outcome measures.

CONCLUSION

Moderate certainty of evidence suggests that the addition of APM to an exercise program adds no benefits in knee function at 5-year follow-up.

Post-traumatic knee osteoarthritis; the role of inflammation and hemarthrosis on disease progression

Knee injuries such as anterior cruciate ligament ruptures and meniscal injury are common and are most frequently sustained by young and active individuals. Knee injuries will lead to post-traumatic osteoarthritis (PTOA) in 25–50% of patients. Mechanical processes where historically believed to cause cartilage breakdown in PTOA patients. But there is increasing evidence suggesting a key role for inflammation in PTOA development. Inflammation in PTOA might be aggravated by hemarthrosis which frequently occurs in injured knees. Whereas mechanical symptoms (joint instability and locking of the knee) can be successfully treated by surgery, there still is an unmet need for anti-inflammatory therapies that prevent PTOA progression. In order to develop anti-inflammatory therapies for PTOA, more knowledge about the exact pathophysiological mechanisms and exact course of post-traumatic inflammation is needed to determine possible targets and timing of future therapies.

Increased Posterior Tibial Slope and Meniscal Slope Could Be Risk Factors for Meniscal Injuries: A Systematic Review

PURPOSE

The purpose of this systematic review was to summarize the available evidence and examine the relation between the posterior tibial slope (PTS) and meniscal slope (MS) and the incidence of meniscal injury.

METHODS

PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science were searched from inception to February 23, 2021. Cohort studies investigating the association between PTS or MS and the risk of meniscal injury were included. Two authors independently conducted the literature search, data extraction, and quality assessment.

RESULTS

Sixteen studies with a total of 2,670 patients were included. For meniscal injury with an anterior cruciate ligament tear, the lateral PTS in the lateral meniscal root tear group (range, 8.0°-12.6°) was significantly higher than that in the control group (range, 4.0°-10.7°). Furthermore, there appeared to be a relation between a greater medial MS and the presence of a ramp lesion (range, 2.6°-6.7° for ramp lesion vs 2.0°-5.1° for control). For degenerative meniscal injury, the medial PTS in the medial meniscal posterior root tear group (range, 6.15°-10.4°) was significantly greater than that in the control group (range, 4.0°-9.8°).

CONCLUSIONS

On the basis of the available evidence, for meniscal injury with an anterior cruciate ligament tear, an increased lateral PTS was associated with a higher risk of lateral meniscal tears and lateral meniscal posterior root tears. Furthermore, there appeared to be a relation between an increased medial MS and a higher risk of ramp lesions. For degenerative meniscal injury, most of the included studies showed that a larger medial PTS could increase the risk of medial meniscal tears and medial meniscal posterior root tears.

LEVEL OF EVIDENCE

Level III, systematic review of Level III studies.

Early Surgery or Exercise and Education for Meniscal Tears in Young Adults

BACKGROUND: Surgery is commonly used to treat meniscal tears; however, to our knowledge, no randomized controlled trials (RCTs) have compared surgery with nonsurgical alternatives in young adults. We hypothesized that early meniscal surgery would be superior to a strategy of exercise and education with the option of surgery later if needed. METHODS: In this pragmatic parallel-group RCT, we enrolled young adults (18-40 years of age) with magnetic resonance imaging–verified meniscal tears eligible for surgery from seven Danish hospitals. Patients were randomly assigned (1:1) to surgery (partial meniscectomy or meniscal repair) or 12-week supervised exercise therapy and education with the option of surgery later if needed. The primary outcome was the difference in change from baseline to 12 months in the mean score of four Knee Injury and Osteoarthritis Outcome Score (KOOS4) subscales covering pain, symptoms, function in sport and recreation, and quality of life, ranging from 0 (worst) to 100 (best). RESULTS: We enrolled 121 young adults (mean age, 29.7 years; 28% were female). In total, 107 participants (88%) completed the 12-month follow-up; 16 participants (26%) from the exercise group crossed over to surgery, while 8 (13%) from the surgery group did not undergo surgery. Intention-to-treat analysis showed no statistically significant difference in change between groups from baseline to 12 months in KOOS4 scores (19.2 vs. 16.4 in the surgery vs. exercise groups; adjusted mean difference, 5.4 [95% confidence interval, −0.7 to 11.4]). No difference in serious adverse events was observed (four vs. seven in the surgery and exercise groups, respectively; P=0.40). Per-protocol and as-treated analyses yielded similar results. CONCLUSIONS: Our results suggest that among young, active adults with meniscal tears, a strategy of early meniscal surgery is not superior to a strategy of exercise and education with the option of later surgery. Both groups experienced clinically relevant improvements in pain, function, and quality of life at 12 months, and one of four from the exercise group eventually had surgery. (Funded by the Danish Council for Independent Research, IMK Almene Fond, Lundbeck Foundation, Spar Nord Foundation, Danish Rheumatism Association, Association of Danish Physiotherapists Research Fund, Research Council at Næstved-Slagelse-Ringsted Hospitals, and Region Zealand; ClinicalTrials.gov number, NCT02995551.)

Occupational risk factors for meniscal lesions: a systematic review and meta-analysis

BACKGROUND

Meniscal lesions are common and are associated with the development of knee osteoarthritis. Knee-straining activities at work such as kneeling or squatting cause high biomechanical stresses on the knee joints that can lead to acute or chronic injuries. The objective of this systematic review is to update the evidence on the potential relationship between occupational risk factors and meniscal lesions.

METHODS

We searched the Medline, Embase and Web of Science databases until August 2021 to identify epidemiological observational studies on the association between occupational risk factors and meniscal lesions. Study selection, data extraction and risk of bias assessment were performed independently by two reviewers. Effect measures were extracted from individual studies and pooled with random effects meta-analysis. Heterogeneity analyses were conducted. We used GRADE (Grades of Recommendations, Assessment, Development and Evaluation) to assess the overall quality of evidence.

RESULTS

The database search resulted in 11,006 references, and 46 additional studies were identified through hand search. Twenty-two studies (represented in 25 publications) met the predefined eligibility criteria and nine records were included in the meta-analysis. There was only one study with an overall low risk of bias. Significant associations between occupational risk factors and the development of meniscal lesions were found for kneeling (effect size (ES) 2.15, 95% CI 1.67-2.76), squatting (ES 2.01, 95% CI 1.34-3.03), climbing stairs (ES 2.28, 95% CI 1.58-3.30), lifting and carrying weights ≥ 10 kg (ES 1.63, 95% CI 1.35-1.96), lifting and carrying weights ≥ 25 kg (ES 1.56, 95% CI 1.08-2.24), playing football on a professional level (ES 5.22, 95% CI 3.24-8.41), working as a hard coal miner (ES 5.23, 95% CI 2.16-12.69) and floor layers (ES 1.99, 95% CI 1.43-2.78). The overall quality of evidence according GRADE was moderate to low.

CONCLUSION

We found consistent evidence of an increased risk of meniscal lesions by occupational knee-straining exposures. Our findings are important for the development of preventive strategies to reduce work-related knee disorders and work absence.

TRIAL REGISTRATION

PROSPERO (registration no. CRD42020196279 ).

The influence of the steep medial posterior tibial slope on medial meniscus tears in adolescent patients: a retrospective case-control study

Background

Several studies have demonstrated a relationship between the posterior tibial slope (PTS) and meniscal tears in adults. However, little is known about the association between the PTS of the adolescents and medial meniscal tears (MMT). The purpose of this study was to evaluate the association between the PTS and MMT in adolescents, and to determine the optimal cut-off values of PTS for discriminating between the MMT and the control groups.

Methods

Between January 2018 and January 2020, a retrospective case-control study was performed. In this study, isolated MMT adolescent patients with no ligamentous injuries were matched by age and sex to a control group of radiologically normal images. The PTS was defined as the angle between the perpendicular line to proximal tibial cortex (PTC) and the tangent line along the tibial plateau. Then, both the medial posterior tibial slope (MPTS) and lateral posterior tibial slope (LPTS) were measured by plain radiographs on the lateral views. In addition, the optimal cut-off values of PTS were determined by the receiver operating characteristic (ROC) curve analysis.

Results

A total of seventy-two patients who met the inclusion criteria were enrolled in the final analysis (36 patients with isolated MMT, 36 controls). The MPTS was greater in the knees with isolated MMT (10.7° ± 2.1°) than that of the control group (8.8° ± 1.7°), showing significant difference (P<0.001). However, there was no significant difference regarding the LPTS between the isolated MMT and controls (11.5 ± 3.4 vs 10.9 ± 2.6, p>0.05). In the ROC curve analysis, the calculated cutoff value of the MPTS discriminating between the groups was 10.3°, with a sensitivity of 73.3% and specificity of 78.9%.

Conclusions

This study demonstrated that steep MPTS is associated with MMT, and MPTS≥10.3° was identified to be a risk factor for MMT in adolescents.

The Epidemiology of Meniscus Injury

Meniscus surgery is one of the most commonly performed orthopedic procedures worldwide. Modifiable risk factors for meniscus injury include body mass index, participation in athletics and occupation. Nonmodifiable risk factors include age, sex, lower extremity alignment, discoid meniscus, ligamentous laxity, and biconcave tibial plateau. Conditions commonly associated with meniscal injury are osteoarthritis, anterior cruciate ligament injury, and tibial plateau fractures. Tear type and location vary by patient age and functional status. Surgical management of meniscus injury is typically cost-effective in terms of quality-adjusted life years. The purpose of this review is to provide an overview of meniscal injury epidemiology by summarizing tear types and locations, associated conditions, and factors that increase the risk for meniscal injury. The economic burden of meniscus injury and strategies to prevent injury to the meniscus are also reviewed.

Small medial femoral condyle morphotype is associated with medial compartment degeneration and distinct morphological characteristics: a comparative pilot study

PURPOSE

Early-onset degeneration of the knee is linked to genetics, overload, injury, and potentially, knee morphology. The purpose of this study is to explore the characteristics of the small medial femoral condyle, as a distinct knee morphotype, by means of a landmark-based three-dimensional (3D) analysis and statistical parametric mapping.

METHODS

Sixteen knees with a small medial femoral condyle (SMC) were selected from a database of patients with distinct knee joint anatomy and 16 gender-matched knees were selected from a control group database. 3D models were generated from the medical imaging. After normalization for size, a set of pre-defined landmark-based parameters was analysed for the femur and tibia. Local shape differences were evaluated by matching all bone surfaces onto each other and comparing the distances to the mean control group bone shape.

RESULTS

The small medial condyle group showed a significant association with medial compartment degeneration and had a 4% and 13% smaller medial condyle anteroposteriorly and mediolaterally, whereas the distal femur was 3% wider mediolaterally. The lateral condyle was 2% smaller anteroposteriorly and 8% wider mediolaterally. The complete tibial plateau was 3% smaller mediolaterally and the medial tibial plateau was 6% smaller.

CONCLUSION

A new knee morphotype demonstrated an increased risk for medial compartment degeneration and was differentiated from a healthy control group based on the following morphological characteristics: a smaller medial femoral condyle and medial tibial plateau, a wider lateral femoral condyle and a wider distal femur on a smaller tibial plateau. This pilot study suggests a role for the SMC knee morphotype in the multifactorial process of medial compartment degeneration.

LEVEL OF EVIDENCE

III.

Characterization and Comparison of Postnatal Rat Meniscus Stem Cells at Different Developmental Stages

Meniscus‐derived stem cells (MeSCs) are a potential cell source for meniscus tissue engineering. The stark morphological and structural changes of meniscus tissue during development indicate the complexity of MeSCs at different tissue regions and stages of development. In this study, we characterized and compared postnatal rat meniscus tissue and MeSCs at different tissue regions and stages of development. We observed that the rat meniscus tissue exhibited marked changes in tissue morphology during development, with day 7 being the most representative time point of different developmental stages. All rat MeSCs displayed typical stem cell characteristics. Rat MeSCs derived from day 7 inner meniscus tissue exhibited the highest self‐renewal capacity, cell proliferation, differentiation potential toward various mesenchymal lineage and the highest expression levels of chondrogenic genes and proteins. Transplantation of rat MeSCs derived from day 7 inner meniscus tissue promoted neo‐tissue formation and effectively protected joint surface cartilage in vivo. Our results demonstrated for the first time that rat MeSCs are not necessarily better at earlier developmental stages, and that rat MeSCs derived from day 7 inner meniscus tissue may be a superior cell source for effective meniscus regeneration and articular cartilage protection. This information could make a significant contribution to human meniscus tissue engineering in the future. stem cells translational medicine2019;8:1318&1329

(A): Meniscus tissue at different tissue regions and stages of development. (B): MeSCs at different tissue regions and stages of development. (C): Intra‐articular injection of MeSCs for meniscus regeneration and OA suppression. *Significant difference between two groups at p < .05. **Significant difference between two groups at p < .01. ***Significant difference between two groups at p < .001. ****Significant difference between two groups at p < .0001. N.S., No significant difference between two groups at p ≥ .05.

Can even experienced orthopaedic surgeons predict who will benefit from surgery when patients present with degenerative meniscal tears? A survey of 194 orthopaedic surgeons who made 3880 predictions

Objectives

To examine the ability of surgeons to predict the outcome of treatment for meniscal tears by arthroscopic partial meniscectomy (APM) and exercise therapy in middle-aged patients.

Design and setting

Electronic survey. Orthopaedic surgeon survey participants were presented 20 patient profiles. These profiles were derived from a randomised clinical trial comparing APM with exercise therapy in middle-aged patients with symptomatic non-obstructive meniscal tears. From each treatment group (APM and exercise therapy), we selected five patients with the best (responders) and five patients with the worst (non-responders) knee function after treatment. 1111 orthopaedic surgeons and residents in the Netherlands and Australia were invited to participate in the survey.

Interventions

For each of the 20 patient profiles, surgeons (unaware of treatment allocation) had to choose between APM and exercise therapy as preferred treatment and subsequently had to estimate the expected change in knee function for both treatments on a 5-point Likert Scale. Finally, surgeons were asked which patient characteristics affected their treatment choice.

Main outcomes

The primary outcome was the surgeons’ percentage correct predictions. We also compared this percentage between experienced knee surgeons and other orthopaedic surgeons, and between treatment responders and non-responders.

Results

We received 194 (17%) complete responses for all 20 patient profiles, resulting in 3880 predictions. Overall, 50.0% (95% CI 39.6% to 60.4%) of the predictions were correct, which equals the proportion expected by chance. Experienced knee surgeons were not better in predicting outcome than other orthopaedic surgeons (50.4% vs 49.5%, respectively; p=0.29). The percentage correct predictions was lower for patient profiles of non-responders (34%; 95% CI 21.3% to 46.6%) compared with responders (66.0%; 95% CI 57.0% to 75.0%; p=0.01).

In general, bucket handle tears, knee locking and failed non-operative treatment directed the surgeons’ choice towards APM, while higher level of osteoarthritis, degenerative aetiology and the absence of locking complaints directed the surgeons’ choice towards exercise therapy.

Conclusions

Surgeons’ criteria for deciding that surgery was indicated did not pass statistical examination. This was true regardless of a surgeon’s experience. These results suggest that non-surgical management is appropriate as first-line therapy in middle-aged patients with symptomatic non-obstructive meniscal tears.

Clinical trial registration

ClinicalTrials.gov Identifier: NCT03462134.

Wild goose chase - no predictable patient subgroups benefit from meniscal surgery: patient-reported outcomes of 641 patients 1 year after surgery

BACKGROUND

Despite absence of evidence of a clinical benefit of arthroscopic partial meniscectomy (APM), many surgeons claim that subgroups of patients benefit from APM.

OBJECTIVE

We developed a prognostic model predicting change in patient-reported outcome 1 year following arthroscopic meniscal surgery to identify such subgroups.

METHODS

We included 641 patients (age 48.7 years (SD 13), 56% men) undergoing arthroscopic meniscal surgery from the Knee Arthroscopy Cohort Southern Denmark. 18 preoperative factors identified from literature and/or orthopaedic surgeons (patient demographics, medical history, symptom onset and duration, knee-related symptoms, etc) were combined in a multivariable linear regression model. The outcome was change in Knee injury and Osteoarthritis Outcome Score (KOOS₄) (average score of 4 of 5 KOOS subscales excluding the activities of daily living subscale) from presurgery to 52 weeks after surgery. A positive KOOS₄ change score constitutes improvement. Prognostic performance was assessed using R² statistics and calibration plots and was internally validated by adjusting for optimism using 1000 bootstrap samples.

RESULTS

Patients improved on average 18.6 (SD 19.7, range -38.0 to 87.8) in KOOS₄. The strongest prognostic factors for improvement were (1) no previous meniscal surgery on index knee and (2) more severe preoperative knee-related symptoms. The model's overall predictive performance was low (apparent R²=0.162, optimism adjusted R²=0.080) and it showed poor calibration (calibration-in-the-large=0.205, calibration slope=0.772).

CONCLUSION

Despite combining a large number of preoperative factors presumed clinically relevant, change in patient-reported outcome 1 year following meniscal surgery was not predictable. This essentially quashes the existence of 'subgroups' with certain characteristics having a particularly favourable outcome after meniscal surgery.

TRIAL REGISTRATION NUMBER

NCT01871272.

Editorial Commentary: Fresh Evidence That There Is Still No Reliable Evidence on How to Best Treat Knee Degenerative Meniscus Tears

Treatment of the degenerative meniscus has been discussed for the past several decades, and proponents of both surgical and conservative treatment have made their points in this ongoing discussion. Unfortunately, there still is no evidence to suggest either treatment algorithm.

Conundrum of mechanical knee symptoms: signifying feature of a meniscal tear?

Background

Mechanical knee symptoms are often considered important in the decision to perform knee arthroscopy on the suspicion of a meniscal tear. We investigated if presence of a meniscal tear at knee arthroscopy in adults is associated with presence of preoperative self-reported mechanical knee symptoms.

Methods

We used data from Knee Arthroscopy Cohort Southern Denmark (KACS). KACS consists of patients aged 18 years or older referred to knee arthroscopy on the suspicion of a meniscal tear at four recruiting hospitals between 1 February 2013 and 31 January 2015. Of 1259 invited patients, 908 (72%) replied to the baseline questionnaire. With 91 patients excluded, the study sample consisted of 641 and 176 patientswithandwithouta meniscal tear confirmed at surgery, respectively. Exposure was meniscal tear as determined by the knee surgeon during arthroscopy. Main outcomes were preoperative mechanical knee symptoms defined as self-reported catching/locking or self-reported inability to straighten knee fully.

Results

55% of all patients reported symptoms of catching/locking and 47% were unable to straighten their knee fully. Preoperative mechanical symptoms were equally prevalent in patientswithandwithouta meniscal tear (prevalence ratio catching/locking 0.89, 95% CI 0.77 to 1.03, and inability to straighten knee fully, prevalence ratio 1.02, 95% CI 0.84 to 1.23).

Interpretation

Patient-reported mechanical symptoms were equally common irrespective of presence or absence of a meniscal tear in patients undergoing arthroscopy for suspicion of a meniscal tear. Our findings suggest that mechanical knee symptoms have a limited value when considering indication for meniscal surgery.

Trial registration number

NCT01871272; Results.