ICRS 2019 - Conference Calendar

Displaying One Session

Plaza B&C Free Papers
Session Type
Free Papers
Date
06.10.2019
Time
13:30 - 15:00
Location
Plaza B&C
Podium Presentation Subchondral Bone

10.2.1 - Subchondral Insufficiency Fractures of the Knee: High Rates of Surgical Management and Conversion to Arthroplasty

Presentation Number
10.2.1
Presentation Topic
Subchondral Bone
Lecture Time
13:30 - 13:39
Session Type
Free Papers
Corresponding Author
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The purpose of this study was to assess clinical outcomes of SIFK based on progression to surgical treatment and arthroplasty, and to evaluate risk factors which increase the progression to arthroplasty in a large retrospective cohort.

Methods and Materials

A retrospective review was performed on patients with an MRI confirmed diagnosis of SIFK. Baseline and final radiographs were reviewed and graded according to Kellgren-Lawrence scores. Baseline MRIs were reviewed for evaluation of meniscus or ligament injuries. Failure was defined as progression to operative management or conversion to arthroplasty.

Results

223 patients (71% female) with mean age of 65.1 years were included. SIFK affected 69% of femurs and 55% of tibias, with medial compartment involvement in 89% of the knees. 74% of medial menisci had root or radial tears with mean extrusion of 3.6mm. Varus malalignment was identified in 60% of knees. 34% progressed to surgical intervention and 29% underwent arthroplasty. The rate of surgery and arthroplasty increased to 47% (p=0.04) and 37% (p=0.09) respectively in patients with greater than 5 years of follow- Up. Ten-year arthroplasty-free survival rate for patients with SIFK on the MFC, SIFK on MT, medial meniscus extrusion, varus alignment, and older was significantly higher than the survival rates compared to their counterparts (p<0.01, p<0.01, p=0.01, p=0.02, p=0.003, respectively).

Figure 1. Survival curves by A. Kellgren-Lawrence (K-L) Grades and subchondral insufficiency fracture of the knee (SIFK) on B. Medial Femoral Condyle (MFC) and C. Medial Tibial Plateau (MT).

sponk clinical.jpg

Conclusion

Subchondral insufficiency fractures predominantly involve the medial compartment of the knee and commonly present with medial meniscus root and radial tears. Approximately one third of the patients progress to total knee arthroplasty. Baseline arthritis, older age, location of insufficiency fracture on the medial femoral condyle and metal tibial plateau, meniscal extrusion, and varus malalignment are all associated with progression to arthroplasty.

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Podium Presentation Rehabilitation and Sport

10.2.2 - The Effect of Affect: Does a Patient's Outlook Influence Their Recovery?

Presentation Number
10.2.2
Presentation Topic
Rehabilitation and Sport
Lecture Time
13:39 - 13:48
Session Type
Free Papers
Corresponding Author

Abstract

Purpose

Several studies suggest a positive relationship between patient-reported functional outcome and activity levels after knee surgery. However, our patients told us that sometimes a low reported outcome is due to high activity levels earlier, suggesting the relationship varies between patients. 'Affect’, the feeling of emotion, is described in terms of positive and negative and known to influence perceived disease symptoms. This study tested two hypotheses: (1) The relationship between activity level and reported functional outcome varies between patients, and (2) A more positive, or less negative, affect correlates with a more positive relationship between activity and functional outcome.

Methods and Materials

Lysholm score, human activity profile (HAP) and Positive and Negative Affect Schedule (PANAS) were collected from cartilage defect patients at 4 timepoints (baseline and 2, 12 and 15 months post-op). From the HAP, the Average Activity Score (AAS) was calculated. A Positive Affect (PA) and Negative Affect (NA) score were calculated from the PANAS. Linear models were used to determine if the slope between AAS and Lysholm varied significantly between patients. Spearman’s correlation was used to determine if the PA or NA score might explain the variation in slopes.

Results

Data was collected from 64 patients (40♂, 24♀; mean age 39±10SD). The mean slope of the relationship between AAS and Lysholm was 0.06 (SD: 0.37, range: -1.3 to 0.7). The variation in slope between patients was significant (p=0.005). Baseline PA score correlated positively with individual patient slope (r=0.26, 95%CI 0.01-0.47; p=0.04) and baseline NA score correlated negatively with individual patient slope (r=-0.29, 95%CI -0.04 to -0.50, p=0.02).

icrs 2019 figure 1.jpgicrs 2019 figure 2.jpg

Conclusion

Our results support both hypotheses, suggesting that patients with a high positive affect score and low negative affect score are more likely to report improved functional outcome with increased activity levels, and vice versa. This could have implications for the prescription of rehabilitation programmes following surgery.

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Podium Presentation Cartilage /Cell Transplantation

10.2.3 - Prospective Evaluation of a Fresh Amniotic Membrane for the Treatment of Cartilage Defects

Presentation Number
10.2.3
Presentation Topic
Cartilage /Cell Transplantation
Lecture Time
13:48 - 13:57
Session Type
Free Papers
Corresponding Author
Disclosure
K. Kimmerling, Organogenesis, Employee K. Mowry, Organogenesis, Employee N. Munson, No significant relationships S. Tabet, Organogenesis, Consultancy

Abstract

Purpose

Cartilage has a limited healing potential due to its lack of vascularization and the innate nature of chondrocytes. Amniotic membranes contain extracellular matrix, proteoglycans, growth factors, and progenitor cell populations1 expected to be beneficial for supporting cartilage repair and protecting the repair site. Previous ovine studies using amniotic membrane for chondral repair have demonstrated improved cartilage quality2,3. In the current clinical study, we evaluated the effectiveness of a fresh, hypothermically-stored amniotic membrane (HSAM) in supporting chondral repair.

Methods and Materials

In 10 patients with ICRS grade III lesions or above, sharp dissection of the defect to normal healthy cartilage was performed. HSAM was laid in the defect bed and secured in place with fibrin glue. Effectiveness of repair was evaluated using MRI, VAS, and KOOS measurements at baseline, 6, 12, 18, and 24 months. Optional biopsies of the chondral repair at 24 months were taken with patient consent and stained using standard histological and immunohistochemical stains for cartilage specific targets.

Results

Currently, the study is fully enrolled, and 2 subjects have reached the end of study (24 months). MOCART scoring demonstrated defect fill in 100% of patients and all repaired defects showed good integration with adjacent cartilage. KOOS scoring showed improvements in all subscales for up to 18 months (Figure 1A). VAS average joint pain scores had an average change from baseline of -27.50±26.52 at 6 months, -27.61±24.42 at 12 months, and -32.32±28.45 at 18 months. At the time of this abstract, one patient biopsy has been stained and showed Collagen II staining within the repair (Figure 1B).

tabet icrs abstract figure 1.jpg

Conclusion

In this 10-patient pilot study, HSAM resulted in improved pain and function scores, defect fill, and high-quality cartilage repair. This evidence supports the use of HSAM in the treatment of chondral defects.

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Podium Presentation Subchondral Bone

10.2.4 - The SIFK Score: A Validated Predictive Model for Arthroplasty Progression after Subchondral Insufficiency Fractures of the Knee

Presentation Number
10.2.4
Presentation Topic
Subchondral Bone
Lecture Time
13:57 - 14:06
Session Type
Free Papers
Corresponding Author
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To create a predictive model utilizing baseline demographic and radiographic characteristics for the likelihood that a patient with SIFK will progress to knee arthroplasty with emphasis on clinical interpretability and ease of use.

Methods and Materials

A retrospective review was performed on patients with MRI-confirmed diagnosis of SIFK. Baseline and final radiographs in addition to MRIs were reviewed for evaluation. Patient and radiographic factors were used in building predictive models for progression to arthroplasty with 50:25:25 splits in Train:Validation:Test data subsets. Six types of models were evaluated for their accuracy/misclassification rate.

Results

figure 1 sonk ml.png

Figure 1. Receiver operator curves (ROC) by model type.

Table 1. SIFK Score: Final clinical model with associated risk of arthroplasty. P-values <0.05 considered significant.

table 1 sonk ml.png

A total of 249 patients (68% female) with a mean age of 64.6 years (SD 10.5) were included. Sixty-six patients (27%) underwent knee arthroplasty at a mean of 4 years of follow-up. All models had an area under the curve (AUC) > 80%. Lasso Regression model was non-inferior to other models and was chosen for easy interpretability. In order of importance, predictors for progression to arthroplasty included (1) lateral meniscus extrusion, (2) Kellgren-Lawrence (K-L) Grade 4, (3) SIFK on MFC, (4) lateral meniscus root tear, and (5) medial meniscus extrusion. The resulting final SIFK Score stratified patients into low-, medium-, and high-risk categories with associated arthroplasty rates of 8.8%, 40.4%, and 78.9% (p<0.001) and an area under the curve (AUC) of 82.5%.

Conclusion

Subchondral insufficiency fractures of the knee can be a source of functional limitation and progress to arthroplasty. This validated clinic-ready model identifies the most important factors in predicting progression to arthroplasty and assists in providing accurate prognostic information based on patient-specific risk factors.

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Podium Presentation Histology

10.2.5 - Histological Assessment and Grading of Cartilage Damage at the Time of Patient Undergoing a Total Knee Replacement

Presentation Number
10.2.5
Presentation Topic
Histology
Lecture Time
14:06 - 14:15
Session Type
Free Papers
Corresponding Author

Abstract

Purpose

Beginning of degenerative cartilage damage heralds the onset of primary osteoarthritis of the knee joint. When the cartilage damage exceeds a certain level, pain and other symptoms start and patient seeks active treatment. Later, a stage is reached when patient is not able to tolerate the pain and agrees for a total knee arthroplasty (TKA). There are presently no research studies highlighting the extent of histological damage of cartilage at this stage. The purpose of this study was to find out the histological stage, when surgeon and patient reaches a clinical end point and both agree for a total knee replacement surgery.

Methods and Materials

A total of consecutive 50 patients undergoing TKA in the orthopedic operation theatre with the diagnosis of primary osteoarthritis were enrolled from June 2013 to June 2015 in the present study. Samples were obtained during the total knee replacement surgery from various compartments of the knee. After the routine processing of the samples, the biopsies samples were stained with H & E stain and Alcian blue stain for light & polarised microscopy. The histologic grading of these lesions was done using the OARSI system and the worst grading from all the samples was taken into consideration

Results

The most common age group undergoing TKR was above the age of 60 and comprised of 39 cases, while 11 patients were below the age of 60. BMI of all the patients was above 25, with 27 patients having BMI < 30. Eight patients were excluded from the study as they were found to be suffering from other pathologies like inflammatory pathologies on histopathology. Of the final 42 patients undergoing TKA for primary osteoarthritis, 18 patients had OARSI grade 3 (42.85%), 23 patients had OARSI grade 4 (54.76%) and only one patient (2.38%) had OARSI grade 5 score.

Conclusion

it was concluded that 42.85% patient reach to a pain threshold of accepting TKR, even when there OARSI grade is 3, while 54.76% reach that threshold at OARSI grade 4. Only an insignificant number of patients had a high tolerance to accept TKR when there OARSI grade was 5. It raises a question if either surgeon or patients are biased towards total knee arthroplasty even when the cartilage degeneration OARSI grade is only 3. This also might put a question on the clinical need for OARSI grade 5 stage.
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Podium Presentation Subchondral Bone

10.2.6 - Post-Arthroscopy Spontaneous Osteonecrosis/Subchondral Insufficiency Fractures of the Knee: Etiology and Clinical Outcomes

Presentation Number
10.2.6
Presentation Topic
Subchondral Bone
Lecture Time
14:15 - 14:24
Session Type
Free Papers
Corresponding Author
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The purpose of this study was to evaluate the potential etiology and resultant outcomes of patients who develop SONK following arthroscopy.

Methods and Materials

A retrospective review was performed of all patients with a MRI diagnosis of SONK following knee arthroscopy over a 10-year period. After excluding open surgeries, 28 patients were included. The mean age was 61 years (29-85), with 50% females and 75% obese patients. Clinical data, outcomes, and conversion-to-arthroplasty were analyzed. The mean follow-up after the SONK diagnosis was 4.1 years (0-10.7).

Results

SONK had a predilection for the medial compartment (n=25, 89%), including the medial femoral condyle (n=21) and/or the medial tibial plateau (n=10). Furthermore, 9 patients had subchondral edema without SONK in another location in the knee. Prior arthroscopic interventions included meniscectomy alone (n=13), meniscectomy with chondroplasty (n=10), and chondroplasty alone (n=4). At final follow-up, 13 patients (43%) went on to conversion-to-arthroplasty (2 UKAs, 11 TKAs). Twelve of the 13 patients converted to arthroplasty had a prior meniscectomy. The survival-free of conversion-to-arthroplasty was 63%, 50%, and 44% at 1 year, 2 years, and 5 years, respectively (Figure 1). Mean time to arthroplasty was 0.76 years (0.1-2.1). There was a significantly increased risk of conversion-to-arthroplasty if SONK was present in both the femur and tibia in the same compartment (p = 0.01). No other variable had a significant impact on conversion-to-arthroplasty.

Figure 1. Kaplan-Meier Survival Curve for the survival-free of conversion-to-arthroplasty with 95% confidence intervals.

sonk post-arthroscopy.png

Conclusion

In patients who develop SONK after knee arthroscopy, it most commonly occurs in the medial compartment in patients who underwent a prior meniscectomy. There is a high rate of conversion-to-arthroplasty in these patients, particularly if present in the same compartment or with a prior meniscectomy.

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Podium Presentation Rehabilitation and Sport

10.2.7 - Three dimensional knee kinematics and kinetics in ACL-deficient patients with and without MMPHT during level walking

Presentation Number
10.2.7
Presentation Topic
Rehabilitation and Sport
Lecture Time
14:24 - 14:33
Session Type
Free Papers
Corresponding Author

Abstract

Purpose

The location of the meniscus tear has been reported to influence kinematics in anterior cruciate ligament deficient (ACLD) knees. Medial meniscus posterior horn tear (MMPHT) often occurred after ACL rupture. The purpose of this study was to investigate three-dimensional (3D) kinematics and kinetics in ACLD knees with and without MMPHT (ACLD+MMPHT, ACLDs) during level walking.

Methods and Materials

Fifteen patients with isolated unilateral ACLD, ten unilateral ACLD+MMPHT, and twenty-two healthy controls underwent gait testing between January 2014 and December 2016. Participant characteristics, as well as gait parameters, were compared among control, ACLDs and ACLD+MMPHT knees.

Results

Compared to the healthy controls, the ACLD knees with and without MMPHT showed significant extension deficiency at maximum extension (flexion: ACLDs: 7.83 ± 4.3°, ACLD+MMPHT: 11.09 ± 7.8°, control: 3.12 ± 4.6°, p = 0.005) and lower extension moments during terminal stance phase of gait. Compared to the healthy controls, significantly increased external tibial rotation during pre-swing phase and lower rotation moments at terminal stance phase were observed in the ACLD+MMPHT knees, but not in the ACLDs knees. No significant differences in gait parameters were observed between ACLDs and ACLD+MMPHT knees during stance phase of walking.

icrsfig1.jpg

Conclusion

The ACLD knees with medial meniscus posterior horn tear exhibited extension deficiency, increased external tibial rotation, lower extension and internal rotation moments during the terminal stance phase compared to healthy control knees, presenting a combination of “stiffening gait” and “pivot shift gait” pattern. The ACLDs knees only presented extension deficiency and lower extension moments compared to healthy control knees, presenting a “stiffening gait”. Medial meniscus posterior horn tear did not significantly affect gait patterns during stance of walking in ACLD knees.

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Podium Presentation Cartilage and Meniscus

10.2.8 - Magnetic Resonance Quantification of Meniscus Vascularity in Pediatric Versus Adult Knees

Presentation Number
10.2.8
Presentation Topic
Cartilage and Meniscus
Lecture Time
14:33 - 14:42
Session Type
Free Papers
Corresponding Author
Disclosure
D. Green: AAOS, POSNA-Board/committee member, Arthrex, Inc-IP royalties, paid consultant, Current Opinion in Pediatrics: Editorial/governing board, Pega Medical: IP royalties D. Helfet: Fx Devices-Stock, Healthpoint Capital, TriMedics-Unpaid consultant, O

Abstract

Purpose

Despite advances in surgical techniques, implant technology, and biological augmentation, one innate limitation to meniscus healing is lack of vascularity. Ability to quantify meniscal vascularity has been limited with previous techniques, and minimal data exists describing differential vascular zones in the skeletally immature meniscus. The objective of this study is to use quantitative contrast-enhanced magnetic resonance imaging (MRI) to compare meniscal vascularity in pediatric specimens to adults. We hypothesize that the developing meniscus has greater and more uniform vascularity throughout all zones.

Methods and Materials

We utilized 10 fresh-frozen human cadaveric knees (5 immature knees, age 0-6 months; 5 mature knees, age 34-67 years). Gadolinium-enhanced MRI was performed using a previously established vascularity quantification protocol. Regions of interest corresponding to peripheral and central zones of the meniscus were identified on pre-contrast coronal images, and signal enhancement (normalized against background tissue) was compared between pre-and post-contrast images (Figure 1).

figure1.png

Results

Quantitative MRI demonstrated increased perfusion in the peripheral zones compared to the central zones (2.3:1 in immature knees and 3:1 in mature knees) in the medial and lateral menisci separately, and both menisci aggregated (Figure 2). Overall, the medial and lateral menisci had similar levels of perfusion in all specimens (45.9% ± 8.3% medial vs. 54.1% ± 8.3% lateral in immature knees; 50.5% ± 11.3% medial vs. 49.5% ± 11.3% lateral in mature knees). Immature specimens demonstrated greater overall normalized meniscal signal uptake, with the 0-month specimen demonstrating the greatest proportional signal enhancement.

figure2.png

Conclusion

While blood flow to peripheral zones is greater than to central zones in both immature and adult menisci, younger menisci receive proportionally greater overall blood flow compared to adults, including greater blood flow to the inner zone, challenging the conventional wisdom of the central zone being avascular.

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Podium Presentation Rehabilitation and Sport

10.2.9 - The Public Perception of Microfracture Surgery: A Cohort Study Comparing the General Public and Elite Athletes

Presentation Number
10.2.9
Presentation Topic
Rehabilitation and Sport
Lecture Time
14:42 - 14:51
Session Type
Free Papers
Corresponding Author
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Microfracture remains the most common repair strategy for treatment of symptomatic cartilage defects of the knee, and the gold standard to which all other cartilage repair procedures are compared. Despite the widespread utilization of microfracture amongst orthopaedic surgeons, there is a paucity of information regarding the public’s perception of the surgery. This study tested the hypothesis that public understanding of the procedure may be unsatisfactory and identified specific misperceptions to be addressed during patient education.

Methods and Materials

A 32 question survey designed to assess an individual’s knowledge of articular cartilage function and the surgical indications, technique, recovery time and general benefits of microfracture surgery was designed and administered to eligible patients. All participants were between 18 and 78 years of age, and were directly recruited from an academic orthopaedic sports medicine clinic and a collegiate athletic training room.

Results

A total of 253 participants (203 patients, 50 collegiate athletes, 132 men, 121 women, mean age 38.7 years) completed the questionnaire. Articular cartilage knowledge was scarce, with only 24% of both cohorts identifying that articular cartilage was found in the knee. In both cohorts, there were no statistically significant differences in survey performance among those who reported moderate, little, or no perceived knowledge of microfracture surgery. Overall, 75.9% of patients and 88% of athletes underestimated postoperative recovery time. 93.1% of patients and 98% of athletes underestimated rates of repeat interventions within five years, and 61% of patients and 90% of athletes overestimated rates of pain reduction with surgical intervention.

Conclusion

The general public and elite athletes demonstrate comparable deficits in knowledge regarding cartilage injury and microfracture surgery. Both cohorts overestimated rates of successful surgical outcomes and underestimated rehabilitation times prior to return to sport. In the age of informed consent, these knowledge deficits should be addressed to improve patient expectations and satisfaction.

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Podium Presentation Cartilage /Cell Transplantation

10.2.10 - Modelling and predicting the long-term clinical outcome of Autologous Chondrocyte Implantation

Presentation Number
10.2.10
Presentation Topic
Cartilage /Cell Transplantation
Lecture Time
14:51 - 15:00
Session Type
Free Papers
Corresponding Author

Abstract

Purpose

Autologous Chondrocyte Implantation (ACI) has been used clinically for over 20 years to treat symptomatic articular cartilage defects. However, not every patient enjoys long-term benefit from ACI. Predicting long-term outcome will help decide if ACI is worthwhile. This study aims to (1) Formulate a statistical model describing long-term clinical outcome of ACI (2) Derive baseline predictors of the model parameters.

Methods and Materials

All ACI patients at our Centre provide Lysholm knee scores before ACI and annually thereafter. Consenting patients treated between 1996 and 2010 were asked if and when they had a knee replacement and had their baseline data (age, gender, number of defects, location, size and grade of defect, previous operations and need for concomitant operations) obtained from records. A multilevel model was fit, describing Lysholm score over time until final followup or knee replacement. Models were compared using likelihood ratio tests, Akaike Information Criteria and R2-values. Baseline variables were added to the overall best fit model as fixed interaction terms with the random parameters to predict variations in Lysholm pattern.

Results

One hundred seventy patients consented (mean followup 7.9 year, range 0.3-17.4). The overall best-fit function describing Lysholm scores over time had a linear first phase lasting 12 months with random slope, and a quadratic second phase with random linear and quadratic parameters (Figure; conditional R2=0.76). Three baseline variables significantly affected score pattern: baseline Lysholm, a patellar or tibial defect, and two or more defects. These three explained 34% of the variation in outcome (marginal R2=0.34).

individualfitspluspredictionsinckudingpreoplysholm.png

Conclusion

Following ACI, Lysholm knee scores follow a biphasic pattern with a 12 month rehabilitation phase when the score changes linearly followed by a longer phase when the score follows a quadratic curve. Three variables explained 31% of the variation in outcome. We implemented the model in a web-based app (https://ork.app) predicting long-term knee function.

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