Is magnetic resonance imaging reliable in predicting clinical outcome after articular cartilage repair of the knee? A systematic review and meta-analysis

Cell-free biomimetic osteochondral scaffold for the treatment of knee articular surface lesions: Clinical outcomes differ based on patient and lesion characteristics

PURPOSE

A cell-free biomimetic osteochondral scaffold was developed to treat cartilage knee lesions, with positive clinical results documented in small case series. However, clear evidence on patient and lesion characteristics that might affect the outcome is still lacking. The aim of this study is to analyse a large cohort of patients treated with this scaffold to investigate factors that could influence the clinical outcome.

METHODS

Two hundred and three patients (mean age 30.7 ± 10.9 years) treated with this scaffold were prospectively evaluated at baseline, 6-, 12- and 24-month follow-up. The clinical outcome was analysed using the International Knee Documentation Committee (IKDC) score, and the activity level was assessed with the Tegner score. The influence of patient and lesion characteristics on clinical outcomes was analysed.

RESULTS

Mild and severe adverse reactions were found in 39.0% and 1.5% of patients, respectively. The failure rate was 2.0%, increasing to 12.3% when including also clinical failures. The IKDC subjective score increased from 43.3 ± 15.9 to 61.0 ± 16.2 at 6 months, 68.3 ± 18.5 at 12 months and 73.8 ± 18.3 at 24 months (p < 0.0005). The Tegner improved from 2.5 ± 1.7 to 4.2 ± 1.7 at 24 months (p < 0.0005), without reaching the pre-injury level (6.0 ± 2.2) (p < 0.0005). The IKDC objective score changed from 68.5% normal and nearly normal knees before the treatment to 90.1% at 24 months. At 24 months, age showed a correlation with the IKDC subjective score (ρ = -0.247; p < 0.0005), women had a lower score (p < 0.0005), as well as patients with patellar lesions (p = 0.002). Previous surgery correlated with lower results (p = 0.003), while better results were found in osteochondritis dissecans (OCD) compared to degenerative lesions (p = 0.001).

CONCLUSION

This cell-free biomimetic scaffold is a safe and effective treatment for cartilage knee lesions, offering positive clinical results at 2 years with a low failure rate. Better outcomes were observed in younger patients, in lesions of the femoral condyles and in OCD, while joints affected by patellar lesions, patients who underwent previous knee surgery, and women may expect lower results.

LEVEL OF EVIDENCE

III, Cohort study.

Effect of Cellular Dosage of Bone Marrow Aspiration Concentrate on the Radiological Outcomes in Knee Osteoarthritis: A Phase I Dose-Escalation Study

Introduction

Knee osteoarthritis(KOA), a chronic degenerative disease, significantly impairs quality of life due to pain and mobility limitations. Traditional treatments focus on symptom management without addressing the underlying disease progression, leading to a growing interest in regenerative medicine approaches. Bone marrow aspirate concentrate (BMAC), rich in mesenchymal stem cells and growth factors, has shown potential for cartilage repair and symptom relief in KOA. Despite promising outcomes, the optimal BMAC dosage for knee OA treatment remains undetermined. This study aims to evaluate the radiological outcomes of varying BMAC dosages in knee OA treatment.

Methods

This prospective controlled dose-escalation study involved 75 patients with early-stage knee OA, categorized into three groups based on BMAC dosage administered 10x106 cells (low-dose group), 50 × 106 cells (medium-dose group), or 100x106 cells (high-dose group). All the patients underwent a single intra-articular injection of BMAC and were monitored over a year. The primary outcomes include magnetic resonance observation of cartilage repair tissue (MOCART 2.0) score to assess the cartilage.

Results

We noted significant improvement in the overall MOCART score (p = 0.027) and subchondral change sub-score (p = 0.048) and defect filling sub-score (p = 0.025) in the medium- and high-dose cohorts compared to the low-dose cohort at 1 year follow-up. Although we noted positive correlation between the clinical and radiological outcome (r = 0.43), we did not find any significant different in the clinical outcome between the treatment groups.

Conclusion

BMAC for OA knee resulted in significant improvement in the radiological scores compared to the baseline. Medium and high doses of BMAC result in significantly higher radiological scores compared to low-dose BMAC at 1 year. However, the radiological improvement did not translate into functional improvement, irrespective of the dosage administered at 1 year. Further research is necessary on the long-term outcomes to understand and optimize the dosing strategy based on clinico-radiological results.

A Biomimetic Osteochondral Scaffold Augmented With Filtered Bone Marrow Aspirate for the Treatment of Joint Surface Lesions in the Knee

BACKGROUND

Multilayered osteochondral scaffolds are becoming increasingly utilized for the repair of knee joint surface lesions (KJSLs). However, the literature on predictive factors is rather limited.

PURPOSE

To (1) evaluate the clinical outcomes and safety of a combined single-step approach using a biomimetic collagen-hydroxyapatite scaffold (CHAS) and filtered bone marrow aspirate (fBMA) for the treatment of KJSLs and (2) identify significant predictors of the treatment outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All patients who underwent surgery because of a KJSL (size ≥1.5 cm2; International Cartilage Regeneration & Joint Preservation Society grades 3-4) using the combination above were selected from a hospital registry database (100 patients; minimum 2-year follow-up). Patient characteristics, medical history, knee joint and lesion status, intraoperative details, and cellular parameters of the injected fBMA were collected. The arthroscopic evaluation of chondral and meniscal tissue quality in all knee compartments was performed using the Chondropenia Severity Score. Treatment outcomes were determined clinically using patient-reported outcome measures (Knee Injury and Osteoarthritis Outcome Score, EuroQol-5 Dimensions-3 Levels, EuroQol-Visual Analog Scale, and Tegner Activity Scale) and by assessing the occurrence of serious adverse events and graft failure. Multivariable regression analysis was performed to identify significant predictors of the treatment outcomes.

RESULTS

At a mean follow-up of 54.2 ± 19.4 months, 78 (87%) patients completed the questionnaires with significant improvements toward the baseline (P < .00625): KOOS Pain subscale from 62 ± 17 to 79 ± 18, KOOS Total score from 57 ± 16 to 70 ± 20, EuroQol-Visual Analog Scale from 61 ± 21 to 76 ± 16, EuroQol-5 Dimensions-3 Levels from 0.57 ± 0.20 to 0.80 ± 0.21, and Tegner Activity Scale from 2.8 ± 1.5 to 3.9 ± 1.9. The graft failure rate was 4%. A longer duration of preoperative symptoms, previous surgery, larger lesions, older age, and female sex were the main negative predictors for the treatment outcomes. The Chondropenia Severity Score and the number of fibroblast colony-forming units in fBMA positively influenced some of the clinical results and safety.

CONCLUSION

A CHAS augmented with fBMA proved to be an adequate and safe approach for the treatment of KJSLs up to midterm follow-up. Based on the subanalysis of predictive factors, the surgical intervention should be performed in a timely and precise manner to prevent lesion enlargement, deterioration of the general knee cartilage status, and recurrent surgical procedures, especially in older and female patients. When a CHAS is used, the quantity of MSCs seems to play a role in augmentation.

REGISTRATION

NCT06078072 (ClinicalTrials.gov identifier).

Outcomes of Particulated Juvenile Articular Cartilage and Association With Defect Fill in Patients With Full-Thickness Patellar Chondral Lesions

Background

Cartilage restoration procedures for patellar cartilage defects have produced inconsistent results, and optimal management remains controversial. Particulated juvenile articular cartilage (PJAC) allograft tissue is an increasingly utilized treatment option for chondral defects, with previous studies demonstrating favorable short-term outcomes for patellar chondral defects.

Purpose

To identify whether there is an association between defect fill on magnetic resonance imaging (MRI) with functional outcomes in patients with full-thickness patellar cartilage lesions treated with PJAC.

Study Design

Case series; Level of evidence, 4.

Methods

A retrospective review of prospectively collected data was conducted on patients treated with PJAC for a full-thickness symptomatic patellar cartilage lesion between March 2014 and August 2019. MRI was performed for all patients at 6, 12, and 24 months postoperatively. Patient-reported outcome measures (PROMs) were obtained preoperatively and at 1, 2, and >2 years postoperatively. Clinical outcome scores-including the International Knee Documentation Committee (IKDC) score, the Kujala, the Knee injury and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS), the Knee Injury and Osteoarthritis Outcome Score-Quality of Life (KOOS-QoL), and the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS)-were analyzed and evaluated for a relationship with tissue fill on MRI.

Results

A total of 70 knees in 65 patients (mean age, 26.6 ± 8.1 years) were identified, of which 68 knees (97%) underwent a concomitant patellar stabilization or offloading procedure. Significant improvements were observed on all postoperative PROM scores at the 1-, 2-, and >2-year follow-up except for the Pedi-FABS, which showed no significant difference from baseline. From baseline to the 2-year follow-up, the KOOS-QoL improved from 24.7 to 62.1, the IKDC improved from 41.1 to 73.5, the KOOS-PS improved from 35.6 to 15, and the Kujala improved from 52 to 86.3. Imaging demonstrated no difference in the rate of cartilage defect fill between the 3-month (66%), 6-month (72%), 1-year (74%), and ≥2-year (69%) follow-ups. No association was observed between PROM scores and the percent fill of cartilage defect on MRI at the 1- and 2-year follow-up.

Conclusion

PROM scores were significantly improved at the 2-year follow-up in patients who underwent PJAC for full-thickness patellar cartilage defects. On MRI, a cartilage defect fill of >66% was achieved by 3 months in most patients. In our sample, PROM scores were not significantly associated with the defect fill percentage at the short-term follow-up.

Biphasic Scaffold Loaded With Autologous Cartilage Yields Better Clinical Outcome and Magnetic Resonance Imaging Filling Compared With Marrow Stimulation for Focal Osteochondral Lesions in the Knee

PURPOSE

To evaluate the effectiveness of marrow stimulation (MS) versus biphasic scaffold loaded with autologous cartilage (scaffold) in treating focal osteochondral lesions of the knee.

METHODS

In total, 54 patients with symptomatic focal chondral or osteochondral lesion in the knee were randomized to either the scaffold group or the MS group. International Knee Documentation Committee subjective score, the Knee Injury Osteoarthritis Outcome Score, and magnetic resonance imaging (MRI) were assessed preoperatively and at 1 and 2 years after operation to compare treatment outcomes. Biopsy and second-look arthroscopy were performed at 1 year postoperatively for consenting patients.

RESULTS

There were 27 patients (mean age 31.33 ± 10.95 years) in the scaffold group, and 27 patients (31.74 ± 11.44) in the MS group. The scaffold group and the MS group both included 23 patients with lesions ≤12.5 × 12.5 mm2 mm in size. In addition, each group had 4 patients with lesions between than 12.5 × 12.5 mm2 and ≤12.5 × 25 mm2. Both interventions achieved significant improvement in clinical outcome scores at 2 years. The scaffold group had greater International Knee Documentation Committee score than the MS group at 2 years (93.85 ± 9.55 vs 92.11 ± 9.84) and in the Symptoms/Stiffness and Sport/Recreation subscales of Knee Injury Osteoarthritis Outcome Score at 2 years (96.57 ± 5.97 vs 93.57 ± 6.52, P < .05) and (90.2 ± 17.76 vs 82.8 ± 16.08, P < .05).

CONCLUSIONS

The use of biphasic scaffold loaded with autologous cartilage in treating focal osteochondral lesions demonstrates superior clinical outcomes and better cartilage refill on magnetic resonance imaging at the 2-year follow-up compared to marrow stimulation.

LEVEL OF EVIDENCE

Level I, Randomized controlled trial.

Treatment of cartilage defects in the patellofemoral joint with matrix-associated autologous chondrocyte implantation effectively improves pain, function, and radiological outcomes after 5-7 years

INTRODUCTION

The aim of the present study was to evaluate midterm outcomes 5-7 years after matrix-associated autologous chondrocyte implantation (MACI) in the patellofemoral joint.

MATERIALS AND METHODS

Twenty-six patients who had undergone MACI using the Novocart® 3D scaffold were prospectively evaluated. Clinical outcomes were determined by measuring the 36-Item Short-Form Health Survey (SF-36) and International Knee Documentation Committee (IKDC) scores and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) values preoperatively and 3, 6, and 12 months, and a mean of 6 years postoperatively. At the final follow-up, the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was evaluated.

RESULTS

Twenty-two patients with 23 focal cartilage defects (19 patella and four trochlea) were available for the final follow-up. The mean defect size was 4.0 ± 1.9 cm2 (range 2.4-9.4 cm2). All clinical outcome scores improved significantly until 5-7 years after MACI (SF-36 score, 61.2 ± 19.6 to 83.2 ± 11.6; P = 0.001; IKDC score, 47.5 ± 20.6 to 74.7 ± 15.5; P < 0.001; and WOMAC, 29.8 ± 15.7 to 8.2 ± 10.3; P < 0.001). The mean MOCART score was 76.0 ± 11.0 at the final follow-up. Nineteen of the 22 patients (86.4%) were satisfied with the outcomes after 5-7 years and responded that they would undergo the procedure again.

CONCLUSION

MACI in the patellofemoral joint demonstrated good midterm clinical results with a significant reduction in pain, improvement in function, and high patient satisfaction. These clinical findings are supported by radiological evidence from MOCART scores.

LEVEL OF EVIDENCE

IV-case series.

Prognostic Factors for Clinical Outcome and Cartilage Regeneration after Implantation of Allogeneic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Large-Sized Cartilage Defects with Osteoarthritis

OBJECTIVE

To analyze the prognostic factors for clinical outcomes and cartilage regeneration after the implantation of allogeneic human umbilical cord blood mesenchymal stem cell (hUCB-MSC) for treating large-sized cartilage defects with osteoarthritis.

DESIGN

This study is a case-series with multiple subgroup analyses that divides the included patients into multiple subgroups based on various factors. Overall, 47 patients who underwent hUCB-MSC implantation were included. The patient-reported outcomes, magnetic resonance imaging (MRI), and second-look arthroscopy were used to assess the outcomes.

RESULTS

Combined realignment surgery significantly correlated with clinical outcomes, particularly pain. No other factors significantly influenced the clinical outcomes in short-term period. Subgroups with large defect sizes or meniscal insufficiency showed significantly poor MRI and arthroscopy outcomes (MRI, P = 0.001, P = 0.001; arthroscopy, P = 0.032, P = 0.042). The logistic regression showed that patients with a 1 cm2 larger defect size were 1.91 times less likely to achieve favorable MRI outcomes (P = 0.017; odds ratio [OR], 1.91). Cut-off value to predict the poor outcome was >5.7 cm2 (area under the curve, 0.756). A cartilage defect size >5.7 cm2 was the major poor prognostic factor for cartilage regeneration on MRI (P = 0.010; OR, 17.46). If the postoperative alignment shifted by 1° opposite to the cartilage defect, it was 1.4 times more likely to achieve favorable MRI outcomes (P = 0.028; OR, 1.4).

CONCLUSION

Combining realignment surgery showed a better prognosis for pain improvement. Cartilage defect size, meniscal function, and postoperative alignment are significant prognostic factors for cartilage regeneration. A cartilage defect size >5.7 cm2 was significantly related to poor cartilage regeneration.

Allogeneic umbilical cord blood-derived mesenchymal stem cell implantation versus microdrilling combined with high tibial osteotomy for cartilage regeneration

This study compared cartilage regeneration outcomes in knee osteoarthritis (OA) using allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation and microdrilling with high tibial osteotomy (HTO). Fifty-four patients (60 knees) were included: 24 (27 knees) in the hUCB-MSC group and 30 (33 knees) in the microdrilling group. Both groups showed significant improvements in pain and functional scores at 6, 12, and 24 months compared to baseline. At 24 months, the hUCB-MSC group had significantly improved scores. Arthroscopic assessment at 12 months revealed better cartilage healing in the hUCB-MSC group. In subgroup analysis according to the defect site, hUCB-MSC implantation showed superior cartilage healing for anterior lesions. In conclusion, both treatments demonstrated effectiveness for medial OA. However, hUCB-MSC implantation had better patient-reported outcomes and cartilage regeneration than microdrilling. The study suggests promising approaches for cartilage restoration in large knee defects due to OA.

Atelocollagen-associated autologous chondrocyte implantation for the repair of large cartilage defects of the knee: Results at three to seven years

BACKGROUND

Recently, various types of engineered autologous chondrocyte implantation (ACI) have been developed. Atelocollagen-associated ACI (A-ACI) is the only ACI procedure covered by Japanese Health Insurance since 2013. The indications of the A-ACI are traumatic cartilage defects and osteochondral dissecans (OCD) for knee joints.

PURPOSE

To evaluate midterm clinical results after A-ACI for the treatment for full-thickness cartilage defects of the knee.

METHODS

Thirteen consecutive patients who underwent A-ACI between 2014 and 2018 had been prospectively enrolled in this study. There were 11 men and 2 women with a mean age of 34 years at the time of surgery. The causes of the cartilage defect were trauma in 10 knees and OCD in 3 knees. The total number of lesions was 15, which were comprised of the medial femoral condyle in 5 knees, the lateral femoral condyle in 5 knees, and the femoral trochlea in 5 knees. The mean size of the lesion was 5.3 cm2. Each knee was clinically and radiologically evaluated preoperatively and postoperatively.

RESULTS

The mean Lysholm score improved significantly from 74.0 points to 94.0 points (p = 0.008) and each subscale in Knee injury and Osteoarthritis Outcome Score improved significantly (p < 0.001) at the mean final follow-up period of 51 months (range, 36-84 months). The magnetic resonance observation of cartilage repair tissue 2.0 score at the mean follow-up of 38 months was significantly higher than that at 2 months postoperatively (p = 0.014). According to the International Cartilage Repair Society (ICRS) grading scale, 3 knees were graded as normal, 3 knees as nearly normal, and 1 knee as severely abnormal in second-look arthroscopic evaluation at a mean of 22 months (range, 8-41 months) after A-ACI.

CONCLUSION

The present study showed a significant subjective and objective clinical improvement in the A-ACI for large cartilage defects of the knee at a mean follow-up of 51 months (range, 36-84 months).

Satisfactory patient-reported outcomes in patients treated with impaction bone grafting and autologous matrix-induced chondrogenesis for osteochondral knee defects

PURPOSE

Osteochondral knee defects usually affect young, active patients and may alter knee biomechanics and progressively lead to joint degeneration. Various treatment options exist with autologous, impaction bone grafting in combination with autologous matrix-induced chondrogenesis (BG-AMIC) being a less-expensive, one-step, promising option. The purpose of this study is to evaluate the clinical and radiological mid-term outcomes of large osteochondral lesions treated with BG-AMIC, identify a possible correlation between the two and report postoperative complications and reoperation rate.

METHODS

A retrospective analysis of 25 patients treated with the BG-AMIC technique for knee osteochondral lesions was performed. Patients were assessed using the following PROMs: the IKDC, the KOOS and the Lysholm score, the Tegner activity scale and a patient acceptable symptom state (PASS). The EQ-5D-5L score was used to assess health-related quality of life. Radiological assessment was performed using the MOCART 2.0 score on a 3 T MRI.

RESULTS

At a mean of 3.8 (± 0.8)-year follow-up, all functional scores increased significantly (p < 0.005) when compared to the preoperative baseline. IKDC increased from 44.5 (± 15.9) to 81.4 (± 14.7), KOOS from 41.5 (± 16.1) to 91.6 (± 11.6) and Lysholm from 54.4 (± 23) to 95.2 (± 5.5) (p < 0.005). The EQ-5D-5L score also revealed a significant improvement [59.9 (± 25) to 93.4 (± 10.2), p < 0.005]. Mean Tegner score reached pre-injury levels. The PASS was positive in 100% of patients. The minimum clinically important difference was reached in all PROMs except for the KOOS Sports subscale. There were no re-operations. Morphological evaluation of the repair tissue using the MOCART 2.0 score revealed a mean total score of 52.8 (± 30.5). A statistically significant, positive correlation was found between the MOCART 2.0 score and the IKDC score, the KOOS ADL subscale and the EQ-5D-5L (p < 0.05).

CONCLUSION

BG-AMIC is a safe and reliable option for treating deep, knee osteochondral lesions, providing a statistically significant and clinically important improvement in patient-reported outcomes. No complications were noticed, and no re-operations were performed after the procedure. A moderate positive correlation between the MOCART 2.0 score and the IKDC, KOOS ADL and EQ-5D-5L was noticed. However, this correlation is not necessarily clinically relevant, and excellent clinical results can be expected even in patients with low MOCART scores.

LEVEL OF EVIDENCE

III.

Microfracture- and Xeno-Matrix-Induced Chondrogenesis for Treatment of Focal Traumatic Cartilage Defects of the Knee: Age-Based Mid-Term Results

The aim of this study was to investigate clinical and instrumental outcomes of the autologous matrix-induced chondrogenesis (AMIC) technique for the treatment of isolated traumatic condyle and femoropatellar cartilage lesions. A total of 25 patients (12 males, 13 females, mean age 47.3 years) treated between 2018 and 2021 were retrospectively reviewed and subdivided into two groups based on age (Group A, age < 45 years; Group B, age > 45 years). A clinical evaluation was performed using the International Knee Documentation Committee (IKDC), Lysholm score and Visual Analogue Score (VAS). Cartilage regeneration was evaluated via magnetic resonance (1.5 Tesla) and classified according to a Magnetic resonance Observation of CArtilage Repair Tissue (MOCART) scoring system. At a minimum follow-up of 2 years, Group A patients obtained greater instrumental results in comparison to group B: in fact, the MOCART score was statistically significantly correlated with IKDC (r = 0.223) (p < 0.001) exclusively in group A. Nevertheless, a significant improvement in clinical functionality was shown in Group B (p < 0.001), demonstrating that this technique is safe, reproducible and capable of offering satisfactory clinical results regardless of age.

In situ observation of cartilage matrix based on two-photon fluorescence microscopy

Articular cartilage lesions remain a major challenge for clinicians and researchers. Several techniques, such as histological scoring, magnetic resonance imaging, and tissue section staining, are available for detecting cartilage degeneration and lesions and evaluating cartilage repairs. Nevertheless, these methods are complex and have numerous influencing factors, which may present obstacles to efficient communication between studies. In this study, we developed a fluorescence observation system that integrated a two-photon laser scanning confocal microscope (TPLSCM) with the second-harmonic generation (SHG) of a cartilage matrix. The observation system enabled the detection of autofluorescence emitted by the cartilage matrix without species specificity, facilitating both qualitative and quantitative analyses of the cartilage matrix. Notably, this observation could be applied three-dimensionally to a fresh specimen in situ up to a depth of 300 μm, obviating the need for traditional histological fixation, slicing, or staining. Furthermore, using this observation system, we reconstructed a three-dimensional (3D) image and a 3D model of the cartilage matrix. The utilization of the 3D fluorescence model may serve as a dependable option for the fabrication of cartilage matrix biomimetic scaffolds in future studies.

A systematic review demonstrating correlation of MRI compositional parameters with clinical outcomes following articular cartilage repair interventions in the knee

OBJECTIVE

Compositional-MRI parameters enable the assessment of cartilage ultrastructure. Correlation of these parameters with clinical outcomes is unclear. This systematic review investigated the correlation of various compositional- MRI parameters with clinical outcome measures following cartilage repair or regeneration interventions in the knee.

DESIGN

This study was registered with PROSPERO and reported in accordance with PRISMA. PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials, and Embase databases were searched. All studies, regardless of type, that presented correlation of compositional- MRI parameters with clinical outcome measures were included. Two researchers independently performed data extraction and QUADAS-2 analysis. Compositional-MRI parameter change following intervention and correlation with clinical outcome measures were evaluated.

RESULTS

19 studies were included. Risk of bias was generally low. 5 different compositional parameters were observed from the included studies. However, due to the significant variability in the reporting of compositional-MRI parameters across studies, meta-analyses were possible only for T2 values and T2 index values (T2 value of repair cartilage relative to normal cartilage). Correlation of T2 values of repair cartilage with clinical outcome score was r ​= ​0.33 [0.15, 0.52]. Correlation of T2 index with clinical outcome score was r ​= ​0.52 [0.32, 0.77].

CONCLUSIONS

Correlation between T2 values and clinical outcome scores following knee cartilage repair were found. The heterogeneity of the correlations extracted from the included studies limited the scope for the meta-analysis. Thus, standardised, high-quality studies are required for better assessment of correlation between compositional MRI parameters and clinical outcome measures after cartilage repair.

REGISTRATION NUMBER

PROSPERO CRD42021287364.Study protocol available on PROSPERO website.

Two-Year Results of Injectable Matrix-Associated Autologous Chondrocyte Transplantation in the Hip Joint: Significant Improvement in Clinical and Radiological Assessment

PURPOSE

Articular cartilage defects are a prevalent consequence of femoroacetabular impingement (FAI) in young active patients. In accordance with current guidelines, large chondral lesions of the hip joint over 2 cm2 are recommended to be treated with matrix-associated, autologous chondrocyte transplantation (MACT); however, the conditions in the hip joint are challenging for membrane-based MACT options. Injectable MACT products can solve this problem. The purpose of the trial was to assess clinical and radiological outcomes 24 months after injectable MACT of focal chondral lesions caused by FAI.

METHODS

We present data of 21 patients with focal cartilage defects of the hip [3.0 ± 1.4 cm2 (mean ± SD)], ICRS Grade III and IV caused by CAM-type impingement, who underwent arthroscopic MACT (NOVOCART® Inject) and FAI correction. The outcome was evaluated with the patient-reported outcome instruments iHOT33 and EQ-5D-5L (index value and VAS), whilst graft morphology was assessed based on the MOCART score over a follow-up period of 24 months.

RESULTS

The iHOT33 score increased significantly from 52.9 ± 21.1 (mean ± SD) preoperatively to 85.8 ± 14.8 (mean ± SD; p < 0.0001) 24 months postoperatively. The EQ-5D-5L index value (p = 0.0004) and EQ-5D VAS (p = 0.0006) showed a statistically significant improvement as well. MRI evaluation after 24 months showed successful integration of the implant in all patients with a complete defect filling in 11 of 14 patients.

CONCLUSIONS

Injectable MACT for the treatment of full-thickness chondral lesions of the hip joint due to FAI in combination with FAI correction improved symptoms, function, and quality of life in the treated cohort. Alongside the treatment of the underlying pathology by the FAI correction, the developed cartilage defect can be successfully repaired by MACT, which is of considerable clinical relevance.

Typical Complications After Cartilage Repair of the Ankle Using Autologous Matrix-Induced Chondrogenesis (AMIC)

Background:

Autologous matrix-induced chondrogenesis (AMIC) for the treatment of osteochondral lesions of the talus (OLT) results in favorable clinical outcomes, yet high reoperation rates. The aim of this study was to report and analyze typical complications and their risk factors after AMIC for OLT.

Methods:

A total of 127 consecutive patients with 130 AMIC procedures for OLT were retrospectively assessed. All AMIC procedures were performed in an open fashion with 106 (81.5%) cases requiring a malleolar osteotomy (OT) to access the OLT. Seventy-one patients (54.6%) underwent subsequent surgery. These cases were evaluated at a mean follow-up of 3.1 years (±2.5) for complications reviewing postoperative imaging and intraoperative findings during revision surgery. Six patients (8.5%) were lost to follow-up. Regression model analysis was conducted to identify factors that were associated with AMIC-related complications.

Results:

Among the 65 (50%) patients who required revision surgery, 18 patients (28%) demonstrated AMIC-related complications with deep fissuring (83%) and thinning (17%) of the AMIC graft. Conversely, 47 patients (72%) underwent subsequent surgery due to AMIC-unrelated reasons including isolated removal of symptomatic hardware (n = 17) and surgery addressing concomitant pathologies with (n = 25) and without hardware removal (n = 5). Previous prior cartilage repair surgery was significantly associated with AMIC graft-associated complications in patients undergoing revision surgery ( P = .0023). Among age, body mass index, defect size, smoking, and bone grafting, smoking was the only factor showing statistical significance with an odds ratio of 3.7 (95% CI 1.24, 10.9; P = .019) to undergo revision surgery due to graft-related complications, when adjusted for previous cartilage repair surgery.

Conclusion:

The majority of revision surgeries after AMIC for OLT are unrelated to the performed AMIC graft but frequently address symptomatic hardware and concomitant pathologies. Both smoking and previous cartilage repair surgery seem to significantly increase the risk of undergoing revision surgery due to AMIC-related complications.

Level of evidence:

Level IV, case series.

Cartilage Regeneration Using Human Umbilical Cord Blood Derived Mesenchymal Stem Cells: A Systematic Review and Meta-Analysis

Background and Objectives: Human umbilical-cord-blood-derived mesenchymal stem cells (hUCB-MSCs) have recently been used in clinical cartilage regeneration procedures with the expectation of improved regeneration capacity. However, the number of studies using hUCB-MSCs is still insufficient, and long-term follow-up results after use are insufficient, indicating the need for additional data and research. We have attempted to prove the efficacy and safety of hUCB-MSC treatment in a comprehensive analysis by including all subjects with knee articular cartilage defect or osteoarthritis who have undergone cartilage repair surgery using hUCB-MSCs. We conducted a meta-analysis and demonstrated efficacy and safety based on a systematic review. Materials and Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. For this study, we searched the PubMed, Embase, Web of Science, Scopus, and Cochrane Library literature databases up to June 2022. A total of seven studies were included, and quality assessment was performed for each included study using the Newcastle−Ottawa Quality Assessment Scale. Statistical analysis was performed on the extracted pooled clinical outcome data, and subgroup analyses were completed. Results: A total of 570 patients were included in the analysis. In pooled analysis, the final follow-up International Knee Documentation Committee (IKDC) score showed a significant increase (mean difference (MD), −32.82; 95% confidence interval (CI), −38.32 to −27.32; p < 0.00001) with significant heterogeneity (I2 = 93%, p < 0.00001) compared to the preoperative score. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at final follow-up were significantly decreased (MD, 30.73; 95% CI, 24.10−37.36; p < 0.00001) compared to the preoperative scores, with significant heterogeneity (I2 = 95%, p < 0.00001). The visual analog scale (VAS) score at final follow-up was significantly decreased (MD, 4.81; 95% CI, 3.17−6.46; p < 0.00001) compared to the preoperative score, with significant heterogeneity (I2 = 98%, p < 0.00001). Two studies evaluated the modified Magnetic Resonance Observation of Cartilage Repair Tissue (M-MOCART) score and confirmed sufficient improvement. In a study analyzing a group treated with bone marrow aspiration concentrate (BMAC), there was no significant difference in clinical outcome or M-MOCART score, and the post-treatment International Cartilage Repair Society (ICRS) grade increased. Conclusion: This analysis demonstrated the safety, efficacy, and quality of repaired cartilage following hUCB-MSC therapy. However, there was no clear difference in the comparison with BMAC. In the future, comparative studies with other stem cell therapies or cartilage repair procedures should be published to support the superior effect of hUCB-MSC therapy to improve treatment of cartilage defect or osteoarthritis.

Early Postoperative CT Scan Provides Prognostic Data on Clinical Outcomes of Fresh Osteochondral Transplantation of the Knee

BACKGROUND

There is a lack of information regarding the ability of imaging studies to predict clinical outcomes after fresh osteochondral allograft (FOCA) transplantation of the knee.

PURPOSE

To determine the value of computed tomography (CT) scans to predict the clinical outcome of FOCA transplantation using the assessment computed tomography osteochondral allograft (ACTOCA) score.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We prospectively collected data from all consecutive patients who underwent FOCA transplantation for osteochondral knee lesions at one institution between August 2017 and August 2019. All patients were followed up for a minimum of 2 years. CT scans performed 6 months after surgery were evaluated by a musculoskeletal radiologist using the ACTOCA scoring system. The radiologist was blinded to the patient's medical history. Clinical outcomes were assessed preoperatively and at 12 and 30 months postoperatively using the International Knee Documentation Committee (IKDC) score, the Kujala score, the Tegner activity scale, and the Western Ontario Meniscal Evaluation Tool (WOMET) score.

RESULTS

A total of 38 cases were included. The ACTOCA score at 6 months after surgery showed a statistically significant correlation with clinical results at 12 and 30 months. The correlation was better at 30 months, showing a high negative correlation with the IKDC score (-0.663) and a moderate negative correlation with the Kujala, WOMET, and Tegner scores (-0.593; -0.547, and -0.593, respectively) (P < .001).

CONCLUSION

A statistically significant correlation between the mean ACTOCA score on CT scans at 6 months and the clinical results measured by the IKDC, Kujala, WOMET, and Tegner scores at 30 months confirmed the predictive value of the ACTOCA score for use in clinical practice.

Minced Autologous Chondral Fragments with Fibrin Glue as a Simple Promising One-Step Cartilage Repair Procedure: A Clinical and MRI Study at 12-Month Follow-Up

OBJECTIVE

The aim of this study was to investigate early radiological and clinical outcome of autologous minced cartilage treatment as a single-step treatment option in patients with a chondral or osteochondral lesion (OCL) in the knee.

DESIGN

Eighteen patients with an OCL in the knee were included. Cartilage from healthy-appearing loose bodies and/or the periphery of the defect were minced into small chips and sealed in the defect using fibrin glue. Preoperatively, and at 3 (n = 14) and 12 (n = 18) months follow-up, magnetic resonance imaging (MRI) was performed. The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 score was used to assess the cartilage repair tissue on MRI at 12 months. The International Knee Documentation Score, Knee Injury and Osteoarthritis Outcome Score, EuroQoL-5D, and Visual Analogue Scale pain were collected preoperatively and 12 months after surgery.

RESULTS

Three months postoperative, MRI showed complete defect filling in 11 out of 14 patients. Mean MOCART 2.0 score at 12 months was 65.0 ± 18.9 with higher scores for lateral femoral chondral lesions compared to medial femoral chondral lesions (75.8 ± 14.3, 52.5 ± 15.8 respectively, P = 0.02). Clinical and statistical significant improvements were observed in the patient-reported outcome measures at 12 months postoperatively compared to preoperatively.

CONCLUSION

Treatment of OCLs using the autologous minced cartilage procedure resulted in good cartilage repair measured by MOCART 2.0. Clinically relevant improvements were observed in the clinical scores. This study suggests autologous minced cartilage as a promising, single-step treatment for OCLs.

Four cases report: Treatment of knee joint cartilage defects using autologous chondrocyte patch implantation

INTRODUCTION

Autologous chondrocyte implantation (ACI) is a crucial method for the treatment of defects in articular cartilage. However, the extant methods for the preparation of autologous chondrocyte patch are relatively complicated and money-consuming. Therefore, an efficient, reliable, easy-to-follow, and cost-effective technique is needed to overcome constraints. This case report aims to introduce an autologous chondrocyte patch fabrication technique to repair knee joint cartilage defects and report our typical cases with a 2-year follow-up.

CASE PRESENTATION

We described four cases in which patients complained of knee joint pain. According to radiological examination, the patients were diagnosed as knee joint cartilage defect. Arthroscopy and autologous chondrocyte patch implantation were performed as well as a 2-year follow up of patients. The autologous chondrocyte patch for knee joint cartilage repair was fabricated using a "sandwich" technique. The preoperative and postoperative knee function was evaluated by four subjective evaluation systems. MRI was performed for all patients to achieve more intuitionistic observation of the postoperative radiological changes of defect sites. The quality of repaired tissue was evaluated by Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART). Postoperative follow-up showed improvement in clinical and MOCART scores for all patients. However, one patient complained of knee joint pain after walking for a long time or recreational activities from 12- to 18-month postoperatively. The location of pain for this patient was not in accordance with the location of cartilage defect.

CONCLUSION

The patients undergoing autologous chondrocyte patch implantation demonstrated clinical improvement and good quality of repaired tissue postoperatively. The procedure is an efficient and cost-effective treatment for knee joint cartilage defect in this report. In addition, patients with osteoarthritis carry the risk of a poor outcome after the procedure, and whether to have a procedure should be considered carefully.

Sustained superiority in KOOS subscores after matrix-associated chondrocyte implantation using spheroids compared to microfracture

PURPOSE

To evaluate the safety and efficacy of matrix-associated autologous chondrocyte implantation (ACI) using spheroids in comparison to arthroscopic microfracture for the treatment of symptomatic cartilage defects of the knee.

METHODS

In a prospective multicenter-controlled trial, patients aged between 18 and 50 years, with single symptomatic focal cartilage defects between 1 and 4 cm² (mean 2.6 ± 0.8, median 2.75, range 1.44-5.00) in the knee were randomized to treatment with ACI with spheroids (n = 52) or microfracture (n = 50). Primary clinical outcome was assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS). Analyses were performed in a defined hierarchical manner where outcomes of ACI were first compared to baseline values followed by a comparison to the microfracture group with repeated-measures ANCOVA with a non-inferiority approach. Subgroup analyses were performed to investigate the influence of age and defect size on the overall KOOS. Secondary clinical outcomes were the magnetic resonance observation of cartilage repair tissue (MOCART), modified Lysholm score and International Knee Documentation Committee (IKDC) examination form. Safety data focused on adverse events. Here the 5 years results are presented at which there were 33 observed cases in the ACI group and 30 in the microfracture group.

RESULTS

The overall KOOS and its five subscores were significantly improved compared to baseline for both the ACI and microfracture group. Non-inferiority of ACI to microfracture was confirmed for the overall KOOS and the subscores, while for the subscores activities of daily living, quality of life and sports and recreation of the threshold for superiority was passed. In the ACI group, a notably more rapid initial improvement of the KOOS was found at three months for the older age group compared to the younger age group and the microfracture group. No other differences were found based on age or defect size. In addition, clinical improvement was found for the MOCART, modified Lysholm and IKDC examination form both the ACI and microfracture group. No safety concern related to either treatment was observed.

CONCLUSION

This study confirms the safety and efficacy of matrix-associated ACI with spheroids at a mid to long-term follow-up. Non-inferiority of ACI to microfracture was confirmed for the overall KOOS and all subscores, while superiority was reached for the subscores activities of daily living, quality of life and sports and recreation in the ACI group. This underlines the importance of ACI for the young and active patients.

LEVEL OF EVIDENCE

I.

Return to Play Criteria Following Surgical Management of Osteochondral Defects of the Knee: A Systematic Review

OBJECTIVE

The objective of this study was to identify and describe the existing literature on criteria used for return to play (RTP) following surgical management of osteochondral defects of the knee.

DESIGN

A systematic review was performed to evaluate the surgical management of osteochondral defects of the knee in skeletally mature patients with a minimum of 2-year follow-up using Level I to IV studies in PubMed EMBASE from January 1998 to January 2016.

RESULTS

Twelve studies with at least one explicitly stated criterion for RTP were identified from a review of 253 published articles. The majority of included studies were Levels II and IV (33%, respectively). Autologous chondrocyte implantation (ACI) was exclusively evaluated in 33.3% of papers and 16.7% evaluated osteochondral allograft transplantation (OCA). Eight different RTP criteria were used alone or in combination across the reviewed studies and time was the most often utilized criterion (83.3%). Minimum time to RTP ranged from 3 to 18 months.

CONCLUSIONS

This systematic review identifies current criteria used in the available literature to dictate RTP. Time from surgery was the most commonly employed criterion across the reviewed studies. Given the complex biological processes inherent to the healing of cartilaginous defects, further research is needed to design more comprehensive guidelines for RTP that are patient-centered and utilize multiple functional and psychological domains relevant to the process of returning to sport.

Clinical and Magnetic Resonance Imaging Outcomes After Microfracture Treatment With and Without Augmentation for Focal Chondral Lesions in the Knee: A Systematic Review and Meta-analysis

BACKGROUND

Focal cartilage lesions represent a common source of knee pain and disability, with the potential for the development and progression of osteoarthritis. Currently, microfracture (MFx) represents the most utilized first-line surgical treatment for small, focal chondral lesions. Recent investigations have examined methods of overcoming the limitations of MFx utilizing various augmentation techniques.

PURPOSE

To perform a systematic review and meta-analysis evaluating clinical and radiographic outcomes in patients undergoing isolated MFx versus MFx augmented with orthobiologics or scaffolds for focal chondral defects of the knee.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed to identify studies evaluating outcomes and adverse events in patients undergoing isolated MFx versus augmented MFx for focal chondral defects in the knee from 1945 to June 1, 2021. Data were extracted from each article that met the inclusion/exclusion criteria. Meta-analyses were performed for all outcomes reported in a minimum of 3 studies.

RESULTS

A total of 14 studies were identified, utilizing 7 different types of injectable augmentation regimens and 5 different scaffolding regimens. Across the 14 studies, a total of 744 patients were included. The mean patient age was 46.8 years (range, 34-58 years), and 58.3% (n = 434/744) of patients were women. The mean final follow-up time was 26.7 months (range, 12-60 months). The mean chondral defect size ranged from 1.3 to 4.8 cm². A post hoc analysis comparing mean improvement in postoperative outcomes scores compared with preoperative values found no significant differences in the improvement in the visual analog scale (VAS), International Knee Documentation Committee (IKDC), or Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores between patients undergoing isolated MFx and those undergoing MFx + augmentation. Patients undergoing MFx + augmentation reported significantly greater improvements in the Lysholm score and postoperative MOCART (magnetic resonance observation of cartilage repair tissue) scores compared with the isolated MFx group.

CONCLUSION

Patients undergoing combined MFx + augmentation reported significant improvements in mean Lysholm and MOCART scores, without significant improvements in VAS, IKDC, or WOMAC scores when compared with patients undergoing isolated MFx.

Patellofemoral joint cartilage restoration with particulated juvenile allograft in patients under 21 years old

BACKGROUND

Patellofemoral joint cartilage defects are difficult to treat due to their unique thickness and topography.

PURPOSE

To report the postoperative outcomes of patients age 21 and younger treated with particulated juvenile allograft cartilage (PJAC) for full-thickness cartilaginous defects of the patellofemoral joint. The primary aim was to report surgical outcomes and complication rates, as well as return to sport activity. A secondary aim was to provide objective scores of defect restoration by magnetic resonance imaging (MRI) assessment.

METHODS

A retrospective review of all PJAC cases conducted between 2012 and 2019 at a single tertiary care urban musculoskeletal institution was conducted. Patients 21 years old or younger with minimum clinical follow up of 1 year and postoperative MRI at a minimum of 6 months were included. Cartilage restoration by MRI was independently assessed using the International Cartilage Repair Society's (ICRS) standardized system.

RESULTS

Thirty four patients, 36 knees, were included, with mean age 16.1 ± 3.1 years old. Return to sport rate among patients who participated in a sport preoperatively was 100%. On independent MRI assessment, two thirds of defects achieved an overall grade of normal or nearly normal, while 28 patients (78%) had majority defect fill. Primary graft failure occurred in two cases and one patient experienced a surgical complication.

CONCLUSION

Restoration of patellofemoral chondral defects in young patients with particulated juvenile allograft results in satisfactory short-term outcomes and postoperative MRI appearance, along with high rates of return to sport and low rate of complications and graft failure. What is known about the subject: Patellofemoral joint cartilage defects are difficult to treat due to their unique thickness and topography. Several cartilage restoration techniques are available, but these rarely achieve the same mechanical properties as native hyaline cartilage. PJAC is a cell-based technique that has demonstrated promise since its introduction in 2007.

WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE

This series of patients adds the largest single cohort of pediatric and adolescent patients who receive PJAC for defects of the patellofemoral joint. Surgeons treating patients in this age group should be aware of every technique, and their respective outcomes.

Correlation of the Histological ICRS II Score and the 3D MOCART Score for the Analysis of Aged Osteochondral Regenerates in a Large Animal Model

OBJECTIVE

Reliable outcome measures are essential to predict the success of cartilage repair techniques. Histology is probably the gold standard, but magnetic resonance imaging (MRI) has the potential to decrease the need for invasive histological biopsies. The 3D magnetic resonance observation of cartilage repair tissue (MOCART) score is a reliable yet elaborate tool. Moreover, literature is controversial concerning the correlation of histology and MRI.

DESIGN

To test the applicability of the International Cartilage Regeneration and Joint Preservation Society (ICRS) II and MOCART 3D score for the evaluation of aged osteochondral regenerates in a large animal model, and to identify correlating histological and MRI parameters. Osteochondral defects in medial femoral condyles of n = 12 adult sheep were reconstructed with biodegradable bilayer implants. About 19.5 months postoperation, n = 10 joints were analyzed with MRI (3D MOCART score). Histological samples were analyzed using the ICRS II score; both pre- and post-training. The intraclass correlation coefficient, the inter-rater reliability, and the 95% confidence interval were calculated. Matching histological and MRI parameters were tested for correlation.

RESULTS

We found a statistically significant correlation of all histological parameters. MRI parameters reflecting "overall" assessments had very strong inter-rater correlations. Statistically significant strong correlations were found for the MRI parameters defect filling, cartilage interface, bone interface, and surface. For defect overall (MRI) and overall assessment (ICRS II), we found a significant yet mild correlation.

CONCLUSIONS

The ICRS II and the 3D MOCART score are applicable to aged osteochondral regenerates. Prior training on the scoring systems is essential. Select MRI and histological parameters correlate; however, the only statistically significant correlation was found for overall assessment.

Computerized tomography scan evaluation after fresh osteochondral allograft transplantation of the knee correlates with clinical outcomes

Purpose

To determine the correlation between the assessment computed tomography osteochondral allograft (ACTOCA) scoring system and clinical outcomes scores. The hypothesis was that the ACTOCA score would show sufficient correlation to support its use in clinical practice.

Methods

We prospectively collected data from all consecutive patients who underwent cartilage restitution with fresh osteochondral allograft (FOCA) transplantation for osteochondral lesions of the knee and had a minimum follow-up of two years. CT scans were performed at three, six and 24 months post-operatively. A musculoskeletal radiologist blinded to the patients’ medical history evaluated the scans using the ACTOCA scoring system. Clinical outcomes collected preoperatively and at three, six and 24 months postoperatively were evaluated using the International Knee Documentation Committee (IKDC), Kujala, the Western Ontario Meniscal Evaluation Tool (WOMET), and the Tegner Activity Scale.

Results

The mean total ACTOCA score showed a statistically significant correlation with the clinical outcome. The correlation was optimal at 24 months. We found a high negative correlation with the IKDC, Kujala and Tegner (− 0.737; − 0.757, and − 0.781 respectively), and a moderate negative correlation with WOMET (− 0.566) (p < 0.001). IKDC, Kujala, WOMET, and Tegner scores showed a significant continuous improvement in all scores (p < 0.001).

Conclusion

The mean total ACTOCA score showed a linear correlation with clinical results in IKDC, Kujala, WOMET, and Tegner scores, being the highest at 24 months post-surgery. This finding supports the use of ACTOCA to standardize CT scan reports following fresh osteochondral allograft transplantation in the knee.

Correlation of Postoperative Imaging With MRI and Clinical Outcome After Cartilage Repair of the Ankle: A Systematic Review and Meta-analysis

Background

Magnetic resonance imaging (MRI) is commonly used for evaluation of ankle cartilage repair, yet its association with clinical outcome is controversial. This study analyzes the correlation between MRI and clinical outcome after cartilage repair of the talus including bone marrow stimulation, cell-based techniques, as well as restoration with allo- or autografting.

Methods

A systematic search was performed in MEDLINE, Embase, and Cochrane Collaboration. Articles were screened for correlation of MRI and clinical outcome. Guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) were used. Chi-square test and regression analysis were performed to identify variables that determine correlation between clinical and radiologic outcome.

Results

Of 2687 articles, a total of 43 studies (total 1212 cases) were included with a mean Coleman score of 57 (range, 33-70). Overall, 93% were case series, and 5% were retrospective and 2% prospective cohort studies. Associations between clinical outcome and ≥1 imaging variable were found in 21 studies (49%). Of 24 studies (56%) using the composite magnetic resonance observation of cartilage repair tissue (MOCART) score, 7 (29%) reported a correlation of the composite score with clinical outcome. Defect fill was associated with clinical outcome in 5 studies (12%), and 5 studies (50%) reported a correlation of T2 mapping and clinical outcome. Advanced age, shorter follow-up, and larger study size were associated with established correlation between clinical and radiographic outcome (P = .021, P = .028, and P = .033).

Conclusion

Interpreting MRI in prediction of clinical outcome in ankle cartilage repair remains challenging; however, it seems to hold some value in reflecting clinical outcome in patients with advanced age and/or at a shorter follow-up. Yet, further research is warranted to optimize postoperative MRI protocols and assessments allowing for a more comprehensive repair tissue evaluation, which eventually reflect clinical outcome in patients after cartilage repair of the ankle.Level of Evidence: Level III, systematic review and meta-analysis.

Treatment of Large Cartilage Defects in the Knee by Hydrogel-Based Autologous Chondrocyte Implantation: Two-Year Results of a Prospective, Multicenter, Single-Arm Phase III Trial

OBJECTIVE

To evaluate the clinical outcome of a hydrogel-based autologous chondrocyte implantation (ACI) for large articular cartilage defects in the knee joint.

DESIGN

Prospective, multicenter, single-arm, phase III clinical trial. ACI was performed in 100 patients with focal full-thickness cartilage defects ranging from 4 to 12 cm² in size. The primary outcome measure was the responder rate at 2 years using the Knee Injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

Two years after ACI treatment, 93% of patients were KOOS responders having improved by ≥10 points compared with their pre-operative level. The primary endpoint of the study was met and demonstrated that the KOOS response rate is markedly greater than 40% with a lower 95% CI (confidence interval) of 86.1, more than twice the pre-specified no-effect level. KOOS improvement (least squares mean) was 42.0 ± 1.8 points (95% CI between 38.4 and 45.7). Mean changes from baseline were significant in the overall KOOS and in all 5 KOOS subscores from Month 3 (first measurement) to Month 24 (inclusive) (P < 0.0001). The mean MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score after 24 months reached 80.0 points (95% CI: 70.0-90.0 points) and 92.1 points in lesions ≤ 5 cm².

CONCLUSIONS

Overall, hydrogel-based ACI proved to be a valuable treatment option for patients with large cartilage defects in the knee as demonstrated by early, statistically significant, and clinically meaningful improvement up to 2 years follow-up. Parallel to the clinical improvements, MRI analyses suggested increasing maturation, re-organization, and integration of the repair tissue.

TRIAL REGISTRATION

NCT03319797; EudraCT No.: 2016-002817-22.

Magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 for the evaluation of retropatellar autologous chondrocyte transplantation and correlation to clinical outcome

BACKGROUND

Matrix-associated chondrocyte transplantation (MACT) has become an established treatment option for cartilage defects.

OBJECTIVE

Three objectives were defined: first, to evaluate retropatellar cartilage grafts using Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 score; second, to determine whether clinical outcome correlates with specific parameters or overall results; third, to screen those parameters for their ability to predict a clinical outcome of Delta IKDC ≥ 20 as a threshold for good clinical response at 12 months.

METHODS

38 patients were included of whom all underwent retropatellar MACT. MRI was performed 3, 6 and 12 months postoperatively. The clinical status was determined using International Knee Documentation Committee Subjective Form (IKDC). Correlations of MOCART 2.0 parameters and Delta IKDC scores were quantified by nonparametric Spearman's R. Those parameters with significant correlations (p < 0.05) were screened for their ability to predict a clinical outcome of Delta IKDC ≥ 20 at 12 months.

RESULTS

Significant correlations were identified for the parameters MOCART total _{6 months} (p < 0.05), Surface _{6 months} (p < 0.05), Surface _{12 months} (p < 0.05), Structure _{6 months} (p < 0.01), Structure _{12 months} (p < 0.05), Subchondral changes _{3 months} (p < 0.0001), Subchondral changes _{6 months} (p < 0.05) and Subchondral changes _{12 months} (p < 0.05). Among all MRI score parameters, Subchondral changes _{3 months} achieved the highest accuracy of 0.76 (0.62-0.86) in predicting Delta IKDC ≥ 20 after 12 months.

CONCLUSION

Some of the MOCART 2.0 parameters show significant correlation with Delta IKDC scores in the postoperative course after retropatellar MACT, which seems to depend on the time interval between surgery and MRI acquisition.

The Role of Magnetic Resonance Imaging in Autologous Matrix-Induced Chondrogenesis for Osteochondral Lesions of the Talus: Analyzing MOCART 1 and 2.0

OBJECTIVE

To determine the role of magnetic resonance imaging (MRI) MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) 1 and 2.0 scores in the assessment of postoperative outcome after autologous matrix-induced chondrogenesis (AMIC) for the treatment of osteochondral lesions of the talus (OLTs). It was hypothesized that preoperative patient factors or OLT morphology are associated with postoperative MOCART scores; yet postoperative clinical outcome is not.

STUDY DESIGN

Cohort study; Level of evidence, 4. This study evaluated isolated AMIC that were implanted on the talus of 35 patients for the treatment of symptomatic OLT. Tegner and AOFAS (American Orthopaedic Foot and Ankle Society) scores were obtained at an average follow-up of 4.5 ± 1.8 years and postoperative MRI scored according to the MOCART 1 and 2.0.

RESULTS

OLT size showed significant correlation with postoperative MRI scores (MOCART 1: P = 0.006; MOCART 2.0: P = 0.004). Bone grafting was significantly associated with a MOCART 1 subscale (signal intensity of repair tissue; P = 0.038). Age and defect size showed significant correlations with MOCART 2.0 subscales (P < 0.05). Patients with shorter follow-up had a significantly higher MOCART 1 score and a trend toward better MOCART 2.0 scores than patients with longer follow-up (64.7 vs. 52.9 months, P = 0.02; 69.4 vs. 60.6 months, P = 0.058). No MOCART score was associated with postoperative patient-reported outcomes (n.s.).

CONCLUSION

Osteochondral lesion size is associated with postoperative MOCART scores in patients treated with AMIC for OLTs, with decreasing MOCART scores over time. Yet clinical outcome does not correlate with any MOCART score. Thus, MOCART assessment seems to have no significant role in the postoperative treatment of asymptomatic patients that underwent AMIC for OLTs.

Combined Bone Marrow Aspirate and Platelet-Rich Plasma for Cartilage Repair: Two-Year Clinical Results

PURPOSE

To evaluate the clinical and biological outcome of combined bone marrow aspirate concentrate (BMAC) and platelet-rich plasma (PRP) on a collagen scaffold for treating cartilage lesions in the knee.

METHODS AND MATERIALS

Ten patients (mean age 29.4 years, range 18-36) suffering from large full-thickness cartilage in the knee were treated with BMAC and PRP from January 2015 to December 2016. In a 1-step procedure autologous BMAC and PRP was seeded onto a collagen scaffold and sutured into the debrided defect. Patients were evaluated by clinical outcome scores (IKDC [International Knee Documentation Committee Subjective Knee Form], KOOS [Knee Injury and Osteoarthritis Outcome Score], and pain score using the Numeric Rating Scale [NRS]) preoperatively, after 3 months, and after 1 and 2 years. Second-look arthroscopies were performed (n = 7) with biopsies of the repair tissue for histology. All patients had magnetic resonance imaging (MRI) preoperatively, after 1 year, and after 2 to 3.5 years with MOCART (magnetic resonance observation of cartilage repair tissue) scores evaluating cartilage repair.

RESULTS

After 1 year significant improvements were found in IKDC, KOOS symptoms, KOOS ADL (Activities of Daily Living), KOOS QOL (Quality of Life), and pain at activity. At the latest follow-up significant improvements were seen in IKDC, KOOS symptoms, KOOS QOL, pain at rest, and pain at activity. MRI MOCART score for cartilage repair improved significantly from baseline to 1-year follow-up. Histomorphometry of repair tissue demonstrated a mixture of fibrous tissue (58%) and fibrocartilage (40%).

CONCLUSION

Treatment of cartilage injuries using combined BMAC and PRP improved subjective clinical outcome scores and pain scores at 1 and 2 years postoperatively. MRI and histology indicated repair tissue inferior to the native hyaline cartilage.

Joint Surface Lesions in the Knee Treated with an Acellular Aragonite-Based Scaffold: A 3-Year Follow-Up Case Series

OBJECTIVE

The study aimed to evaluate the clinical outcome and repair capacity of a cell-free aragonite-based scaffold in patients with an isolated symptomatic joint surface lesion (JSL) of the knee.

DESIGN

Thirteen patients (age 33.5 ± 8.9; female 23%; body mass index 25.3 ± 3.4, K/L [Kellgren-Lawrence] 1.8) with a JSL (2.6 ± 1.7 cm² [1.0-7.5 cm²]) of the distal femur were enrolled in a single-center prospective case series. Safety and clinical outcome was assessed by the KOOS (Knee Injury and Osteoarthritis Outcome Score), IKDC (International Knee Documentation Committee), Lysholm, and Tegner activity scale at baseline and 6, 12, 18, 24, and 36 months follow-up. The MOCART 2.0 and scaffold integration were evaluated on magnetic resonance imaging at 12, 24, and 36 months postoperatively.

RESULTS

Primary outcome (KOOS pain) improved with 36.5 ± 14.7 points at 12 months (P = 0.002) and 41.2 ± 14.7 points at 36 months (P = 0.002) follow-up. Similar increasing trends were observed for the other KOOS subscales, IKDC, and Lysholm score, which were significantly better at each follow-up time point relative to baseline (P < 0.05). Activity level increased from 2.75 ± 1.6 to 4.6 ± 2.2 points at final follow-up (P = 0.07). The MOCART was 61.7 ± 12.6 at 12 months and 72.9 ± 13.0 at 36 months postoperatively. Sixty-six to 100% implant integration and remodeling was observed in 73.3% cases at 36 months. No serious adverse events were reported.

CONCLUSION

The study demonstrated that the biphasic aragonite-based scaffold is a safe and clinically effective implant for treating small-medium sized JSLs of the distal femur in a young and active patient cohort. The implant showed satisfying osteointegration and restoration of the osteochondral unit up to 3 years postimplantation.

Autologous Matrix-Induced Chondrogenesis (AMIC) for Isolated Retropatellar Cartilage Lesions: Outcome after a Follow-Up of Minimum 2 Years

PURPOSE

To evaluate autologous matrix-induced chondrogenesis (AMIC) for isolated focal retropatellar cartilage lesions and the influence of patellofemoral (PF) anatomy on clinical outcomes at a minimum of 2-year follow-up.

METHODS

Twenty-nine consecutive patients (31 knees) who underwent retropatellar AMIC with a mean age of 27.9 ± 11.0 years were evaluated at a follow-up averaging 4.1 ± 1.9 years (range, 2-8 years). Patient factors, lesion morphology, and patient-reported outcome measures, including Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner, Kujula score, and visual analogue scale (VAS) score were collected. PF anatomy was assessed on pre- and postoperative imaging, and subsequently correlated to outcome scores and failure to determine risk factors for poor outcome.

RESULTS

At final follow-up, the AMIC graft failed in 4 cases (12.9%) at a mean follow-up of 21 ± 14.1 months. Patients with failed grafts had a significantly smaller patellar and Laurins's PF angle than patients whose graft did not fail (P = 0.008 and P = 0.004, respectively). Concomitant corrective surgery for patellar instability was performed in 29 knees (93.5%). Grafts that did not fail presented with an average Kujala score of 71.3 ± 16.9, KOOS Pain of 76.2 ± 16.6 and Tegner scores of 4.2 ± 1.8. The patellar angle was significantly associated with the patient's satisfaction level (r = 0.615; P < 0.001).

CONCLUSION

AMIC for retropatellar cartilage lesions in combination with concomitant corrective surgery for patellar instability results in low failure rate with satisfactory clinical outcome and patient satisfaction of almost 80% at mid-term follow-up. As most failures occurred in patients without concurrent tibial tubercle osteotomy and both a smaller patellar and Laurins's PF angle were associated with less favorable outcome, this study supports the growing evidence for the need of unloading retropatellar cartilage repair, when indicated.

LEVEL OF EVIDENCE

Case series; level of evidence, 4.

The MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) 2.0 Knee Score and Atlas

OBJECTIVE

Since the first introduction of the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) score, significant progress has been made with regard to surgical treatment options for cartilage defects, as well as magnetic resonance imaging (MRI) of such defects. Thus, the aim of this study was to introduce the MOCART 2.0 knee score - an incremental update on the original MOCART score - that incorporates this progression.

MATERIALS AND METHODS

The volume of cartilage defect filling is now assessed in 25% increments, with hypertrophic filling of up to 150% receiving the same scoring as complete repair. Integration now assesses only the integration to neighboring native cartilage, and the severity of surface irregularities is assessed in reference to cartilage repair length rather than depth. The signal intensity of the repair tissue differentiates normal signal, minor abnormal, or severely abnormal signal alterations. The assessment of the variables "subchondral lamina," "adhesions," and "synovitis" was removed and the points were reallocated to the new variable "bony defect or bony overgrowth." The variable "subchondral bone" was renamed to "subchondral changes" and assesses minor and severe edema-like marrow signal, as well as subchondral cysts or osteonecrosis-like signal. Overall, a MOCART 2.0 knee score ranging from 0 to 100 points may be reached. Four independent readers (two expert readers and two radiology residents with limited experience) assessed the 3 T MRI examinations of 24 patients, who had undergone cartilage repair of a femoral cartilage defect using the new MOCART 2.0 knee score. One of the expert readers and both inexperienced readers performed two readings, separated by a four-week interval. For the inexperienced readers, the first reading was based on the evaluation sheet only. For the second reading, a newly introduced atlas was used as an additional reference. Intrarater and interrater reliability was assessed using intraclass correlation coefficients (ICCs) and weighted kappa statistics. ICCs were interpreted according to Koo and Li; weighted kappa statistics were interpreted according to the criteria of Landis and Koch.

RESULTS

The overall intrarater (ICC = 0.88, P < 0.001) as well as the interrater (ICC = 0.84, P < 0.001) reliability of the expert readers was almost perfect. Based on the evaluation sheet of the MOCART 2.0 knee score, the overall interrater reliability of the inexperienced readers was poor (ICC = 0.34, P < 0.019) and improved to moderate (ICC = 0.59, P = 0.001) with the use of the atlas.

CONCLUSIONS

The MOCART 2.0 knee score was updated to account for changes in the past decade and demonstrates almost perfect interrater and intrarater reliability in expert readers. In inexperienced readers, use of the atlas may improve interrater reliability and, thus, increase the comparability of results across studies.

Initial Validation of a Modified MRI Scoring System for Assessing Outcomes after Single-Surface Osteochondral Shell Allograft Transplantation in the Knee

The Osteochondral Allograft Magnetic Resonance Imaging Scoring System (OCAMRISS) provides a reproducible method for imaging-based grading for osteochondral allograft (OCA) transplants. However, the OCAMRISS does not account for larger whole-surface OCA shell grafts, and has not been validated for assessing outcomes after shell OCA transplantation. Therefore, the objective of this study was to evaluate a modified OCAMRISS for assessing single-surface shell OCAs in the knee based on strength of correlations for a modified OCAMRISS score with graft success and patient-reported outcomes for pain and function. With institutional review board approval and informed patient consent, patients who underwent large single-surface shell OCA transplantation and magnetic resonance imaging (MRI) exams at 1-year postsurgery were identified from a prospectively enrolled registry. All patients with a minimum of 2 years of clinical follow-up were included in the present study. A modified OCAMRISS, as well as assessment of the percentage of OCA bone incorporation, was used to score each knee. Two radiologists, blinded to patient demographics and outcomes, reviewed all MRIs together to determine a consensus score for each category and %-incorporation for each OCA. Thirteen patients (7 F, 6 M; mean age = 29.8 ± 9.4; mean body mass index = 27.1 ± 5.8); 8 medial femoral condyle, 4 patella, and 1 medial tibial plateau shell OCAs were evaluated. Mean modified OCAMRISS score was 5.2 ± 2.8, range (2-12) and %-integration was 72.7 ± 33.8, range (0-100). Moderate to strong correlations were noted for 1-year modified OCAMRISS total score with final follow-up (FFU) visual analog scale (VAS) pain (r = +0.58) and Single Assessment Numeric Evaluation (SANE) function (r = -0.7) scores, and for 1-year %-incorporation with FFU VAS pain (r = -0.76) and SANE function (r = +0.83) scores. The modified OCAMRISS total score and %-incorporation assessments determined at 1 year following single-surface shell OCA transplantation correlate well with initial patient outcomes and have clinical applicability for monitoring patients after large-shell OCA transplants in the knee.

Typical MRI-pattern suggests peak maturation of the ACI graft 2 years after third-generation ACI: a systematic review

PURPOSE

The purpose of the present article was (1) to systematically review the current literature and (2) to collect data regarding the postoperative magnetic resonance imaging (MRI) appearance of third-generation autologous chondrocyte implantation (ACI) grafts and (3) to provide an overview of imaging findings at various postoperative time points.

METHODS

A systematic review of the literature in Medline (Pubmed) and Embase was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles which reported the post-operative MRI morphological outcomes following the use of third-generation ACI for treatment of knee cartilage lesions were included. All MRI results were allocated to six different time intervals: ≤ 3 months, > 3-6 months, > 6 months-1 year, > 1 year-2 years, > 2-5 years and > 5 years after surgery.

RESULTS

A total of 22 studies were included and the study populations ranged from 13 to 180 patients adding up to a total of 951 patients. Parameters such as defect fill, border integration, surface contour, graft morphology and integrity of the subchondral lamina all improve gradually with a peak two years following surgery suggesting complete graft maturation at this time point. After this peak, a statistically insignificant decline is noted for most of the parameters. Signal intensity was found to gradually shift from hyperintense to isointense in the first 36 months and to hypointense later on. Contrarily, subchondral bone edema is not only a postoperative feature of the procedure but also can reappear or persist up to ten years after surgery. As graft failures can appear after two years, consequently, the MRI composite score is also affected.

CONCLUSION

Recurring patterns in postoperative MRI appearance were observed in certain parameters including defect filling, graft signal intensity and structure, border integration of the graft while parameters like subchondral bone tend to be unpredictable. Given the heterogenous findings in terms of clinical correlation, and relating that aspect to the patterns found in this review, an MRI is justified at three months, one year, two years and five years after surgery, unless the clinical symptomatology and individual patient needs dictate otherwise.

LEVEL OF EVIDENCE

IV.

Reliability of the MOCART score: a systematic review

BACKGROUND

The present systematic review analysed the available literature to assess reliability of the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score in the evaluation of knee and ankle osteochondral lesions.

METHODS

All the studies using the MOCART score for knee and/or talus chondral defects were accessed in March 2021. A multivariate analysis was performed to assess associations between the MOCART score at last follow-up and data of patients at baseline, clinical scores and complications. A multiple linear model regression analysis was used.

RESULTS

The MOCART score evidenced no association with patient age (P = 0.6), sex (P = 0.1), body mass index (P = 0.06), defect size (P = 0.9), prior length of symptoms (P = 0.9) or visual analogue scale (P = 0.07). For chondral defects of the knee, no statistically significant association was found between the MOCART score and the International Knee Documentation Committee (P = 0.9) and with the Lysholm Knee Scoring Scales (P = 0.2), Tegner Activity Scale (P = 0.2), visual analogue scale P = 0.07), rate of failure (P = 0.2) and revision (P = 0.9). For chondral defect of the talus, no statistically significant associations were found between the MOCART score and the American Orthopedic Foot and Ankle Score (P = 0.3), Tegner Activity Scale (P = 0.4), visual analogue scale (P = 0.1), rate of failure (P = 0.1) and revision (P = 0.7).

CONCLUSION

The MOCART score demonstrated no association with patient characteristics and with the surgical outcome in patients who underwent surgical management for knee and talus chondral defects.

LEVEL OF EVIDENCE

Level IV.

Device for Assessing Knee Joint Dynamics During Magnetic Resonance Imaging

BACKGROUND

Knee assessment with and without load using magnetic resonance imaging (MRI) can provide information on knee joint dynamics and improve the diagnosis of knee joint diseases. Performing such studies on a routine MRI-scanner require a load-exerting device during scanning. There is a need for more studies on developing loading devices and evaluating their clinical potential.

PURPOSE

Design and develop a portable and easy-to-use axial loading device to evaluate the knee joint dynamics during the MRI study.

STUDY TYPE

Prospective study.

SUBJECTS

Nine healthy subjects.

FIELD STRENGTH/SEQUENCE

A 0.25 T standing-open MRI and 3.0 T MRI. PD-T₂ -weighted FSE, 3D-fast-spoiled-gradient-echo, FS-PD, and CartiGram sequences.

ASSESSMENT

Design and development of loading device, calibration of loads, MR safety assessment (using projectile angular displacement, torque, and temperature tests). Scoring system for ease of doing. Qualitative (by radiologist) and quantitative (using structural similarity index measure [SSIM]) image-artifact assessment. Evaluation of repeatability, comparison with various standing stances load, and loading effect on knee MR parameters (tibiofemoral bone gap [TFBG], femoral cartilage thickness [FCT], tibial cartilage thickness [TCT], femoral cartilage T₂ -value [FCT2], and tibia cartilage T₂ -value [TCT2]). The relative percentage change (RPC) in parameters due to the device load was computed.

STATISTICAL TEST

Pearson's correlation coefficient (r).

RESULTS

The developed device is conditional-MR safe (details in the manuscript and supplementary materials), 15 × 15 × 45 cm³ dimension, and <3 kg. The ease of using the device was 4.9/5. The device introduced no visible image artifacts, and SSIM of 0.9889 ± 0.0153 was observed. The TFBG intraobserver variability (absolute difference) was <0.1 mm. Interobserver variability of all regions of interest was <0.1 mm. The load exerted by the device was close to the load during standing on both legs in 0.25 T scanner with r > 0.9. Loading resulted in RPC of 1.5%-11.0%, 7.9%-8.5%, and -1.5% to 13.0% in the TFBG, FCT, and TCT, respectively. FCT2 and TCT2 were reduced in range of 1.5-2.7 msec and 0.5-2.3 msec due to load.

DATA CONCLUSION

The proposed device is conditionally MR safe, low cost (material cost < INR 6000), portable, and effective in loading the knee joint with up to 50% of body weight.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 1.

Cell-Free Biomimetic Osteochondral Scaffold for the Treatment of Knee Lesions: Clinical and Imaging Results at 10-Year Follow-up

BACKGROUND

Cell-free devices have been introduced to restore osteochondral defects, avoiding the limitations of cell-based procedures. Among these, an osteochondral scaffold made of type I collagen and hydroxyapatite has been investigated with promising results up to medium-term follow-up. However, the clinical and imaging results over time still need to be documented.

PURPOSE

To evaluate the clinical outcome and tissue maturation at long-term follow-up after the implantation of the osteochondral scaffold.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 24 patients (7 women, 17 men; age, 36 ± 9.5 years) underwent surgical implantation of the osteochondral scaffold and were prospectively evaluated before surgery, at 2-, 5-, and 10-year follow-up. The mean defect size was 2.9 ± 1.4 cm². Patients were evaluated using the International Knee Documentation Committee (IKDC) subjective and objective scores, and the activity level was documented with the Tegner score. Magnetic resonance imaging (MRI) evaluation involved the use of the magnetic resonance observation of cartilage repair tissue score combined with 5 more variables focused on the bone layer.

RESULTS

A statistically significant improvement of all clinical scores was documented from the baseline to the final evaluation. The IKDC subjective score improved from the preoperative level to 2 years (41 ± 13.2 and 77.1 ± 14.6, respectively) (P < .0005), with stable results up to 10 years (77.4 ± 19.4). The IKDC objective score changed from 52% of normal and nearly normal knees before the treatment to 84% at 10 years (P < .0005). Tegner sports activity at the final evaluation (3.8 ± 1.7) was higher compared with the preoperative level (1.6 ± 1.1; P < .05), but it remained significantly lower compared with the preinjury level (5.5 ± 2.6; P < .05). Treatment failed in 1 patient. Persisting graft alterations were observed on MRI scans, although without correlating with the clinical outcome.

CONCLUSION

The regenerative potential of this scaffold is limited, as demonstrated by the signal alterations persisting over time on MRI scans. On the other hand, the clinical improvement was significant and stable over time both in terms of subjective and objective outcomes, including activity level, with overall good results.

Comparison of Bone Marrow Aspirate Concentrate and Allogenic Human Umbilical Cord Blood Derived Mesenchymal Stem Cell Implantation on Chondral Defect of Knee: Assessment of Clinical and Magnetic Resonance Imaging Outcomes at 2-Year Follow-Up

Biological repair of cartilage lesions remains a significant clinical challenge. A wide variety of methods involving mesenchymal stem cells (MSCs) have been introduced. Because of the limitation of the results, most of the treatment methods have not yet been approved by the Food and Drug Administration (FDA). However, bone marrow aspirate concentrate (BMAC) and human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) implantation were approved by Korea FDA. The aim of this study was to evaluate clinical and magnetic resonance imaging (MRI) outcomes after two different types of MSCs implantation in knee osteoarthritis. Fifty-two patients (52 knees) who underwent cartilage repair surgery using the BMAC (25 knees) and hUCB-MSCs (27 knees) were retrospectively evaluated for 2 years after surgery. Clinical outcomes were evaluated according to the score of visual analogue scale (VAS), the International Knee Documentation Committee (IKDC) subjective, and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Cartilage repair was assessed according to the modified Magnetic Resonance Observation of Cartilage Repair Tissue (M-MOCART) score and the International Cartilage Repair Society (ICRS) cartilage repair scoring system. At 2-year follow-up, clinical outcomes including VAS, IKDC, and KOOS significantly improved (P < 0.05) in both groups; however, there were no differences between two groups. There was no significant difference in M-MOCART [1-year (P = 0.261), 2-year (P = 0.351)] and ICRS repair score (P = 0.655) between two groups. Both groups showed satisfactory clinical and MRI outcomes. Implantation of MSCs from BMAC or hUCB-MSCs is safe and effective for repairing cartilage lesion. However, large cases and a well-controlled prospective design with long-term follow-up studies are needed.

Is T2 mapping reliable in evaluation of native and repair cartilage tissue of the knee?

PURPOSE

To evaluate the effect of imaging plane and experience of observers on the reliability of T2 mapping of native and repair cartilage tissue of the knee.

METHODS

Fifteen consecutive patients from two randomised controlled trials (RCTs) were included in this cross-sectional study. Patients with an isolated knee cartilage lesion were randomised to receive either debridement or microfracture (RCT 1) or debridement or autologous chondrocyte implantation (RCT 2). T2 mapping was performed in coronal and sagittal planes two years postoperatively. A musculoskeletal radiologist, a resident of radiology and two orthopaedic surgeons measured the T2 values independently. Intraclass Correlation Coefficient (ICC) with 95% Confidence Intervals was used to calculate the inter- and intraobserver agreement.

RESULTS

Mean age for the patients was 36.8 ± 11 years, 8 (53%) were men. The overall interobserver agreement varied from poor to good with ICCs in the range of 0.27- 0.76 for native cartilage and 0.00 - 0.90 for repair tissue. The lowest agreement was achieved for evaluations of repair cartilage tissue. The estimated ICCs suggested higher inter- and intraobserver agreement for radiologists. On medial femoral condyles, T2 values were higher for native cartilage on coronal images (p < 0.001) and for repair tissue on sagittal images (p < 0.001).

CONCLUSIONS

The reliability of T2 mapping of articular cartilage is influenced by the imaging plane and the experience of the observers. This influence may be more profound for repair cartilage tissue. This is important to consider when using T2 mapping to measure outcomes after cartilage repair surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02637505 and NCT02636881 , registered December 2015.

LEVEL OF EVIDENCE

II, based on prospective data from two RCTs.

Bifunctional Labeling of Rabbit Mesenchymal Stem Cells for MR Imaging and Fluorescence Microscopy

PURPOSE

Longitudinal imaging studies are important in the translational process of stem cell-based therapies. Small animal imaging models are widely available and practical but insufficiently depict important morphologic detail. In contrary, large animal models are logistically challenging and costly but offer greater imaging quality. In order to combine the advantages of both, we developed an intermediate-sized rabbit animal model for cartilage imaging studies.

PROCEDURES

Rabbit mesenchymal stem cells (rMSC) were isolated as primary cultures from the bone marrow of New Zealand white rabbits. rMSC were subsequentially transduced lentivirally with eGFP and magnetically labeled with the iron oxide ferucarbotran. eGFP expression was evaluated by flow cytometry and iron uptake was analyzed by isotope dilution mass spectrometry and Prussian blue staining. Fluorescence microscopy of eGFP-transduced rMSC was performed. Viability and induction of apoptosis were assessed by XTT and caspase-3/-7 measurements. The chondrogenic potential of labeled cells was quantified by glycosaminoglycan contents in TGF-β3 induced pellet cultures. Labeled and unlabeled cells underwent magnetic resonance imaging (MRI) at 1.5 T before and after differentiation using T1-, T2-, and T2*-weighted pulse sequences. Relaxation rates were calculated. rMSCs were implanted in fibrin clots in osteochondral defects of cadaveric rabbit knees and imaged by 7 T MRI. T2* maps were calculated. Statistical analyses were performed using multiple regression models.

RESULTS

Efficiency of lentiviral transduction was greater than 90 %. Fluorescence signal was dose dependent. Cellular iron uptake was significant for all concentrations (p < 0.05) and dose dependent (3.3-56.5 pg Fe/cell). Labeled rMSC showed a strong, dose-dependent contrast on all MR pulse sequences and a significant decrease in T2 and T2* relaxation rates. Compared with non-transduced or unlabeled controls, there were no adverse effects on cell viability, rate of apoptosis, or chondrogenic differentiation. MRI of labeled rMSCs in osteochondral defects showed a significant signal of the transplant with additional high-resolution anatomical information.

CONCLUSIONS

This intermediate-sized rabbit model and its bifunctional labeling technique allow for improved depiction of anatomic detail for noninvasive in vivo rMSC tracking with MRI and for immunohistological correlation by fluorescence microscopy.

Reliability of the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) 2.0 knee score for different cartilage repair techniques-a retrospective observational study

OBJECTIVES

To evaluate the reliability of the MOCART 2.0 knee score in the radiological assessment of repair tissue after different cartilage repair procedures.

METHODS

A total of 114 patients (34 females) who underwent cartilage repair of a femoral cartilage lesion with at least one postoperative MRI examination were selected, and one random postoperative MRI examination was retrospectively included. Mean age was 32.5 ± 9.6 years at time of surgery. Overall, 66 chondral and 48 osteochondral lesions were included in the study. Forty-eight patients were treated with autologous chondrocyte implantation (ACI), 27 via osteochondral autologous transplantation, five using an osteochondral scaffold, and 34 underwent microfracture (MFX). The original MOCART and MOCART 2.0 knee scores were assessed by two independent readers. After a minimum 4-week interval, both readers performed a second reading of both scores. Inter- and intrarater reliabilities were assessed using intraclass correlation coefficients (ICCs).

RESULTS

The MOCART 2.0 knee score showed higher interrater reliability than the original MOCART score with an ICC of 0.875 versus 0.759, ranging from 0.863 in the MFX group to 0.878 in the ACI group. Intrarater reliability was good with an overall ICC of 0.860 and 0.866, respectively. Overall, interrater reliability was higher for osteochondral lesions than for chondral lesions, with ICCs of 0.906 versus 0.786.

CONCLUSIONS

The MOCART 2.0 knee score enables the assessment of cartilage repair tissue after different cartilage repair techniques (ACI, osteochondral repair techniques, MFX), as well as for different lesion types with good intra- and interrater reliability.

KEY POINTS

• The MOCART 2.0 knee score provides improved intra- and interrater reliability when compared to the original MOCART score. • The MOCART 2.0 knee score enables the assessment of cartilage repair tissue after different cartilage repair techniques (ACI, osteochondral repair techniques, MFX) with similarly good intra- and interrater reliability. • The assessment of osteochondral lesions demonstrated better intra- and interrater reliability than the assessment of chondral lesions in this study.

A new computed tomography scoring system to assess osteochondral allograft transplantation for the knee: inter-observer and intra-observer agreement

AIM OF THE STUDY

To describe a new semiquantitative computed tomography (CT) scoring system for multi-feature analysis of cartilage defect repair by osteochondral allografts for the knee and to assess its intra-observer and inter-observer variability.

METHOD

A semiquantitative assessment CT osteochondral allograft (ACTOCA) scoring system was designed based on fresh osteochondral allograft transplantations for the knee. The system includes five CT features: density relative to host bone, integration at the host-graft junction, surface percentage with a discernible cleft at the host-graft junction, cystic changes, and intra-articular fragments. Inter-observer variability was calculated by three observers blinded to the patient's medical history and treatment. Intra-observer variability was also determined.

RESULTS

Inter-observer agreement was moderate to substantial for all CT score components and intra-observer agreement was moderate to almost perfect for all CT score components (κ > 0.5, p < 0.05).

CONCLUSION

The ACTOCA score is a reliable tool to evaluate integration of osteochondral allograft transplantations. It provides an accurate evaluation of bone changes and may help to standardize CT scan reports following osteochondral allograft transplantation for the knee.

Knee articular cartilage injury treatment with matrix-induced autologous chondrocyte implantation (MACI): correlation at 24 and 120 months between clinical and radiological findings using MR arthrography

OBJECTIVE

To evaluate the long-term evolution of matrix-induced autologous chondrocyte implantation (MACI) with magnetic resonance (MR) arthrography and verify the correlation between radiological and clinical findings.

MATERIALS AND METHODS

Twenty-six patients (20 m/6f) were diagnosed with knee chondral injuries and treated with MACI implantation. Each patient received MR arthrography and clinical examination at mid-term (range 22-36 months) and long term (range 96-194 months) after surgery. MR arthrography was performed with dedicated coil and a 1.5-Tesla MR unit. The modified MOCART scale was used to evaluate the status of chondral implants. Implant coating, integration to the border zone, and the surface and structure of the repaired tissue were evaluated. Presence of bone marrow oedema was evaluated. The Cincinnati Knee Rating System (CKRS) was used for clinical assessment.

RESULTS

At long term, 4/26 patients had complete alignment; 5/26 had a complete integration of the margins; in 4/26 cases, the implant surface was undamaged; in 14/26 cases, the reparative tissue was homogeneous. In 9/26 cases, the implant showed isointense signal compared to articular cartilage, while the presence of subchondral bone oedema was documented in 19/26 cases. The average radiological score decreased from 59.2 (mid-term) to 38.6 (long term). The average clinical score decreased from 8.9 to 8.3.

CONCLUSIONS

Decrease in clinical results was not significant (0.6 points p = .06), but mMOCART scores decreased significantly (p = .00003). Although imaging studies showed deterioration of the grafts, the patients did not have significant clinical deterioration (231/250).

Clinical and Radiological Outcomes After Autologous Matrix-Induced Chondrogenesis Versus Microfracture of the Knee: A Systematic Review and Meta-analysis With a Minimum 2-Year Follow-up

Background:

Microfracture (MFx) is the most common procedure for treating chondral lesions in the knee; however, initial improvements decline after 2 years. Autologous matrix-induced chondrogenesis (AMIC) may overcome this shortcoming by combining MFx with collagen scaffolds. However, the outcomes of AMIC and MFx in the knee have not been compared.

Purpose:

To compare the clinical and radiological outcomes of AMIC and MFx over a minimum 2-year follow-up.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search of the MEDLINE, Embase, and Cochrane Library databases identified studies of patients who underwent AMIC or MFx and that reported validated clinical outcome measure and/or radiological evaluation findings at a follow-up of ≥2 years. There were 2 reviewers who performed study selection, a risk of bias assessment, and data extraction.

Results:

Overall, 29 studies were included in this systematic review. The mean improvement on the Lysholm score, Tegner activity scale, and visual analog scale for pain did not differ significantly between the 2 procedures. The mean improvement on the International Knee Documentation Committee (IKDC) subjective score was significantly greater in the AMIC (45.9 [95% CI, 36.2-55.5]) than in the MFx (27.2 [95% CI, 23.3-31.1]) group (P < .001). In addition, the mean magnetic resonance observation of cartilage repair tissue score was significantly higher in the AMIC (69.3 [95% CI, 55.1-83.5]) versus MFx (41.0 [95% CI, 27.3-54.7]) group (P = .005), and the mean adequate defect filling rate on magnetic resonance imaging scans was significantly better in the AMIC (77.3% [95% CI, 66.7%-87.9%]) versus MFx (47.9% [95% CI, 29.2%-66.6%]) group (P = .008) (odds ratio, 1.58 [95% CI, 1.07-2.33]).

Conclusion:

No significant differences in clinical outcomes, except for the IKDC subjective score, were found between the AMIC and MFx groups. Greater improvement in IKDC subjective scores and magnetic resonance imaging findings were seen in patients treated with AMIC compared with MFx at a minimum 2-year follow-up.

Three-dimensional, Scaffold-Free, Autologous Chondrocyte Transplantation: A Systematic Review

Background:

A 3-dimensional, scaffold-free, and completely autologous form of chondrocyte transplantation (ACT3D) has been developed and applied in clinical practice in the past decade to overcome disadvantages of previous-generation procedures.

Purpose:

To document and analyze the available literature on the results of ACT3D in the treatment of articular chondral lesions in the knee and hip joints.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

All studies published in English addressing ACT3D were identified and included those that fulfilled the following criteria: (1) level 1 through 4 evidence, (2) measures of radiological or functional/clinical outcome, and (3) outcome related to cartilage lesions of the knee and hip joints.

Results:

A total of 10 studies were selected: 2 randomized controlled trials, 1 cohort study, and 7 case series. The studies revealed significant increases in patients’ subjective quality of life, satisfaction, pain reduction, and improvement in joint function at short- to medium-term follow-up. Magnetic resonance imaging-assisted examination and second-look arthroscopy showed a hyaline-like repair tissue with a high degree of defect filling and integration.

Conclusion:

ACT3D shows promising results in the therapy of articular cartilage defects in the knee as well as in the hip, but well-designed, long-term studies are lacking. ACT3D might have relevant advantages over common matrix-associated autologous chondrocyte transplantation products, but systematic evaluation and randomized controlled studies are crucial to verify the potential of this tissue-engineered approach.

Donor Site Evaluation After Osteochondral Autograft Transplantation for Capitellar Osteochondritis Dissecans

BACKGROUND

Osteochondral autograft transplantation (OAT) for capitellar osteochondritis dissecans (OCD) requires harvesting of tissue from the asymptomatic knee joint. However, donor site morbidity (DSM) in such cases remains unclear.

PURPOSE

To evaluate DSM and postoperative radiographic findings in patients undergoing OAT for advanced capitellar OCD.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Eighty-six juvenile athletes underwent OAT for advanced capitellar OCD. The 2000 International Knee Documentation Committee subjective score, rate of return to sports, and symptoms in the donor knee were assessed at a mean follow-up of 86 months (range, 28-185 months). Additionally, 49 of the 86 patients were assessed by radiographic and magnetic resonance imaging (MRI) findings of the knee donor site. DSM was defined according to the usual criterion (persistent symptoms for >1 year or the need for subsequent intervention) and a stricter criterion (the presence of any symptoms, such as effusion, patellofemoral complaints, crepitation, unspecified disturbance, stiffness, pain/instability during activities, and osteoarthritic change). The stricter criterion was also used to allocate patients into a DSM group and a no-DSM group.

RESULTS

Two and 11 patients were determined to have DSM according to the usual and stricter criteria, respectively. All patients returned to the competitive level of their sports. The mean International Knee Documentation Committee score was 99.0. MRI findings showed abnormal signal intensity in 17 patients (35%) and hypertrophic changes in 11 patients (22%) at the donor harvest sites. The MOCART (magnetic resonance observation of cartilage repair tissue) score was higher in the no-DSM group (mean, 68.2) than in the DSM group (mean, 52.9) (P = .027).

CONCLUSION

OAT for juvenile athletes with advanced capitellar OCD provided good clinical outcomes. The DSM rate was relatively low (2.3%) with the usual criterion but high (12.8%) with the stricter criterion. MRI showed an abnormal signal intensity and hypertrophy in some cases.

Cartilage repair surgery prevents progression of knee degeneration

PURPOSE

To investigate, whether cartilage repair surgery for focal osteochondral defects at the knee results in less degenerative changes over 6 years in a MR imaging follow-up than morphologically initially identical defects in non-operated control subjects from the osteoarthritis initiative (OAI).

METHODS

A total of 32 individuals received baseline and follow-up MRI. In n = 16 patients with cartilage repair [osteochondral autograft transfer system (OATS), n = 12; spongiosa-augmented matrix-associated autologous chondrocyte implantation (MACI), n = 4] MRI was performed preoperatively and after 5.7 ± 2.3 year follow-up. Baseline MRIs of non-operated subjects from the OAI were screened for initially identical cartilage defects (n = 16). Morphological knee abnormalities were assessed using WORMS, AMADEUS and MOCART scores. A sagittal 2D MSME sequence was implemented for quantitative cartilage T2 relaxation time measurements in all (0, 2, 4, 6 and 8-years) follow-ups from the OAI and in the postoperative MRI protocol.

RESULTS

For both groups, focal osteochondral defects were located at the femoral condyle in 8/16 cases (5 medial, 3 lateral) and at the patella in 8/16 cases. At baseline, the mean cartilage defect size ± SD was 1.4 ± 1.3 cm² for the control group and 1.3 ± 1.2 cm² for the cartilage repair group (n.s.). WORMS scores were not significantly different between the cartilage repair group and the control group at baseline [mean difference ± SEM (95%CI); 0.5 ± 2.5 (- 4.7, 5.7), n.s.]. During identical follow-up times, the progression of total WORMS scores [19.9 ± 2.3 (15.0, 24.9), P < 0.001] and of cartilage defects scores in the affected (P < 0.001) and in the opposing (P = 0.029) compartment was significantly more severe in non-operated individuals (P < 0.05). In non-operated subjects, T2 values increased continuously from baseline to the 8-year follow-up (P = 0.001).

CONCLUSIONS

Patients with cartilage repair showed less progression of degenerative MRI changes at 6-year follow-up than a control cohort from the OAI with initially identical osteochondral defects. Patients with focal cartilage defects may profit from cartilage repair surgery since it may prevent progression of early osteoarthritis at the knee joint.

LEVEL OF EVIDENCE

Prognostic study, Level II.