Definition of pertinent parameters for the evaluation of articular cartilage repair tissue with high-resolution magnetic resonance imaging

Seven-Year Longitudinal Study: Clinical Evaluation of Knee Osteoarthritic Patients Treated with Mesenchymal Stem Cells

Background/Objectives: Numerous studies have demonstrated the safety and efficacy of intraarticular stem cell injections for treating osteoarthritic knee joints, reporting symptom reduction and pain relief within a few months of treatment. Here, we report the results of a 7-year follow-up after a single intraarticular injection of 0.5-1 × 107 autologous adipose tissue-derived mesenchymal stem cells in patients with OA (Kellgren-Lawrence grade 2 to 4). Methods: Nine patients were treated, and two patients had bilateral disease. Patients were evaluated clinically and radiologically using X-ray and MRI. A comprehensive statistical analysis was undertaken to evaluate the obtained results. Results: All clinical scores and range of motion significantly improved within the first six months after injection. At the 18-month time point, a significant improvement in cartilage structure was observed on MRI while X-ray showed no changes in subchondral bone of distal femur and proximal tibia. At the 60-month time point, the clinical scores were still improved compared to baseline, except for the range of motion, which decreased almost back to the baseline level. At 84 months, the clinical scores decreased significantly toward the baseline level, but the MRI structural characteristics of cartilage still remained significantly better than those measured at baseline. Conclusions: Adipose tissue-derived stem cell therapy has substantial long-term clinical effects on patients with knee osteoarthritis.

Preoperative and Postoperative Imaging and Outcome Scores for Osteochondral Lesion Repair of the Ankle

Cartilage lesions to the ankle joint are common and can result in pain and functional limitations. Surgical treatment aims to restore the damaged cartilage's integrity and quality. However, the current evidence for establishing best practices in ankle cartilage repair is characterized by limited quality and a low level of evidence. One of the contributing factors is the lack of standardized preoperative and postoperative assessment methods to evaluate treatment effectiveness and visualize repaired cartilage. This review article seeks to examine the importance of preoperative imaging, classification systems, patient-reported outcome measures, and radiological evaluation techniques for cartilage repair surgeries.

Mid-term results of autologous matrix-induced chondrogenesis for large chondral defects in hips with femoroacetabular impingement syndrome

Aims

The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI).

Methods

This single-centre study focused on a cohort of 24 patients with cam- or pincer-type FAI, full-thickness femoral or acetabular chondral lesions, or osteochondral lesions ≥ 2 cm2, who underwent surgical hip dislocation for FAI correction in combination with AMIC between March 2009 and February 2016. Baseline data were retrospectively obtained from patient files. Mid-term outcomes were prospectively collected at a follow-up in 2020: cartilage repair tissue quality was evaluated by MRI using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Patient-reported outcome measures (PROMs) included the Oxford Hip Score (OHS) and Core Outcome Measure Index (COMI). Clinical examination included range of motion, impingement tests, and pain.

Results

A total of 12 hips from 11 patients were included (ten males, one female, mean age 26.8 years (SD 5.0), mean follow-up 6.2 years (SD 5.2 months)). The mean postoperative MOCART score was 66.3 (SD 16.3). None of the patients required conversion to total hip arthroplasty. Two patients had anterior impingement. External hip rotation was moderately limited in four patients. There was a correlation between MOCART and follow-up time (rs = -0.61; p = 0.035), but not with initial cartilage damage, age, BMI, or imaging time delay before surgery. PROMs improved significantly: OHS from 37.4 to 42.7 (p = 0.014) and COMI from 4.1 to 1.6 (p = 0.025). There was no correlation between MOCART and PROMs.

Conclusion

Based on the reported mid-term results, we consider AMIC as an encouraging treatment option for large cartilage lesions of the hip. Nonetheless, the clinical evidence of AMIC in FAI patients remains to be determined, ideally in the context of randomized controlled trials.

Return to Sports Activity After Microfracture for Osteochondral Lesion of the Talus in Skeletally Immature Children

BACKGROUND

Osteochondral lesions of the talus (OLTs) are among the common sports-related injuries. However, there are few reports on the return to sports after OLT surgery in skeletally immature children. This study was performed to evaluate the return to sports after microfracture for OLTs in skeletally immature children.

METHODS

This study involved 17 ankles of 16 patients (mean age, 13.2 years; range, 10-16 years) with open tibial epiphyses on magnetic resonance imaging (MRI) who underwent microfracture for OLTs <10 mm in diameter and confirmation of lesion instability under arthroscopy. Nine of 17 ankles had additional lateral ankle ligament stabilization. All patients were participating in some form of sports. The Japanese Society for Surgery of the Foot (JSSF) score, Ankle Activity Score (AAS), return to sports rate, lesion size, grade of subchondral bone marrow edema, and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score on MRI were evaluated after microfracture. The mean postoperative follow-up period was 53.5 months.

RESULTS

The mean JSSF score significantly improved from 76.1 points preoperatively to 94.9 points at the final follow-up (P < .01). The mean AAS showed no change from preoperative state to final follow-up. The return to sports rate was 100%. The lesion size significantly decreased from 76.3 to 56.7 mm2 in area (P = .02) and from 283.2 to 185.6 mm3 in volume (P = .05). The bone marrow edema grade decreased in 8 of 17 ankles. The total MOCART score showed a significant improvement from 6 months to 1 year postoperatively (P = .05).

CONCLUSION

All skeletally immature children who underwent microfracture for OLTs in this study were able to return to sports activity and showed improvements in clinical scores and MRI parameters. Microfracture may be considered an effective first-line treatment for OLTs <10 mm in diameter in skeletally immature athletes.

LEVEL OF EVIDENCE

Level IV, retrospective case-control study.

The role of imaging in the diagnosis, staging, and management of the osteochondral lesions of the talus

Osteochondral lesions of the talus (OLT) represent an abnormality of the articular cartilage and sub-chondral bone. The abnormality is typically associated with trauma though the exact aetiology remains unknown. Multiple staging systems have been developed to classify the abnormality and management can vary from conservative treatment to different surgical options. Early diagnosis is essential for optimal outcome and all imaging modalities have a role to play in patient management. The aim of this article is to review the pathology, classification, multimodality imaging appearances of OLT, and how the imaging affects patient management.

10-Year Prospective Clinical and Radiological Evaluation After Matrix-Induced Autologous Chondrocyte Implantation and Comparison of Tibiofemoral and Patellofemoral Graft Outcomes

BACKGROUND

Long-term outcomes in larger cohorts after matrix-induced autologous chondrocyte implantation (MACI) are required. Furthermore, little is known about the longer-term clinical and radiological outcomes of MACI performed in the tibiofemoral versus patellofemoral knee joint.

PURPOSE

To present the 10-year clinical and radiological outcomes in patients after MACI and compare outcomes in patients undergoing tibiofemoral versus patellofemoral MACI.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between September 2002 and December 2012, 204 patients who underwent MACI were prospectively registered into a research program and assessed preoperatively and at 2, 5, and 10 years postoperatively. Of these patients, 168 were available for clinical review at 10 years, with 151 (of a total of 182) grafts also assessed via magnetic resonance imaging (MRI). Patients were evaluated using the Knee injury and Osteoarthritis Outcome Score, a visual analog scale for pain frequency and severity, satisfaction, and peak isokinetic knee extensor and flexor strength. Limb symmetry indices (LSIs) were calculated for strength measures. Grafts were scored on MRI scans via the MOCART (magnetic resonance observation of cartilage repair tissue) system, with a focus on tissue infill and an overall MRI graft composite score.

RESULTS

All patient-reported outcome measures improved (P < .0001) up to 2 years after surgery. Apart from the significant increase (P = .004) in the peak isokinetic knee extensor LSI, no other patient-reported outcome measure or clinical score had changed significantly from 2 to 10 years. At the final follow-up, 92% of patients were satisfied with MACI to provide knee pain relief, with 76% satisfied with their ability to participate in sports. From 2 to 10 years, no significant change was seen for any MRI-based MOCART variable nor the overall MRI composite score. Of the 151 grafts reviewed via MRI at 10 years, 14 (9.3%) had failed, defined by graft delamination or no graft tissue on MRI scan. Furthermore, of the 36 patients (of the prospectively recruited 204) who were not available for longer-term review, 7 had already proceeded to total knee arthroplasty, and 1 patient had undergone secondary MACI at the same medial femoral condylar site because of an earlier graft failure. Therefore, 22 patients (10.8%) essentially had graft failure over the period. At the final follow-up, patients who underwent MACI in the tibiofemoral (vs patellofemoral) joint reported significantly better Knee injury and Osteoarthritis Outcome Score subscale scores for Quality of Life (P = .010) and Sport and Recreation (P < .001), as well as a greater knee extensor strength LSI (P = .002). Even though the tibiofemoral group demonstrated better 10-year MOCART scores for tissue infill (P = .027), there were no other MRI-based differences (P > .05).

CONCLUSION

This study reports the long-term review of a prospective series of patients undergoing MACI, demonstrating good clinical scores, high levels of patient satisfaction, and acceptable graft survivorship at 10 years. Patients undergoing tibiofemoral (vs patellofemoral) MACI reported better long-term clinical outcomes, despite largely similar MRI-based outcomes.

Second-Look Arthroscopy Shows Inferior Cartilage after Bone Marrow Stimulation Compared with Other Operative Techniques for Osteochondral Lesions of the Talus: A Systematic Review and Meta-Analysis

OBJECTIVE

To compare cartilage quality after different surgical interventions for osteochondral lesions of the talus (OLT), evaluated by second-look arthroscopy. Secondary aims were to report concomitant diagnoses, and to correlate cartilage quality with clinical and radiological outcomes. This review hypothesizes that the cartilage repair after bone marrow stimulation (BMS) is inferior to the other available treatment options.

METHODS

PROSPERO ID: CRD42022311489. Studies were retrieved through PubMed, EMBASE (Ovid), and Cochrane Library. Studies were included if they reported cartilage quality after second-look investigation after surgical treatment of OLT. The primary outcome measure was the cartilage quality success and failure rates (%) per surgical intervention group. Correlations between the cartilage quality and clinical or radiological outcomes were calculated.

RESULTS

Twenty-nine studies were included, comprising 586 ankles that had undergone second-look arthroscopy on average 16 months after initial surgery. The success rate for BMS was 57% (95% confidence interval [CI] = 48%-65%), for fixation (FIX) 86% (95% CI = 70%-94%), for osteo(chondral) transplantation (OCT) 91% (95% CI = 80%-96%), for cartilage implementation techniques (CITs) 80% (95% CI = 69%-88%), and for retrograde drilling 100% (95% CI = 66%-100%). The success rate of BMS was significantly lower than FIX, OCT, and CIT (P < 0.01). There were no significant differences between other treatment groups. A moderate positive significant correlation between the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score and the International Cartilage Repair Society score (ICRS) was found (ρ = 0.51, P < 0.001).

CONCLUSIONS

Successful restoration of cartilage quality was found in the majority of surgically treated OLTs. However, BMS yields inferior cartilage quality compared with FIX, OCT, and CIT. Study Design. Systematic review and meta-analysis. Level of evidence. Level IV, systematic review and meta-analysis.

Top 50 Most-Cited Studies about Osteochondritis Dissecans

Purpose

To determine the 50 most frequently cited studies on osteochondritis dissecans (OCD) and to conduct a bibliometric analysis of these studies.

Methods

We performed a search within the Clarivate Web of Science database, identifying articles published before December 2022 that encompass topics related to OCD. The search was conducted using the keywords "Osteochondritis Dissecans OR Osteochondritis OR Dissecans."Search results were then filtered using predetermined guidelines and criteria, and the 50 most-cited articles were selected for analysis. Extracted data included title, journal, design, main topic, joint, citations, year, country of origin, and level of evidence.

Results

The search yielded 3,865 articles. The 50 most-cited articles were published between 1957 and 2018, with the greatest proportion published from 2000 to 2009 (60%). The most frequently studied topic was treatment (68%), followed by etiology (14%) and imaging (8%). The majority of articles had Level IV evidence (36%) and the largest proportion focused on the knee joint (36%), followed by the ankle (32%), and elbow (6%). The mean citation count per article was 287 (range: 157-1,050), with the most-cited articles primarily published from 2000 to 2003. The leading country of origin was the United States, accounting for 19 publications.

Conclusions

Most of the top 50 most-cited articles regarding OCD are about treatment, and the knee is the most-studied joint. The majority of the articles were Level IV evidence and were published in the United States between 2000 and 2009.

Clinical Relevance

The top 50 most-cited studies list will provide researchers, medical students, residents, and fellows with a foundational list of the most important and influential academic contributions regarding osteochondritis dissecans (OCD).

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.

Effectiveness and safety of arthroscopy combined with radial extracorporeal shockwave therapy for osteochondritis of the talus: a prospective, single-centre, randomized, double-blind study

Aims

Arthroscopic microfracture is a conventional form of treatment for patients with osteochondritis of the talus, involving an area of < 1.5 cm2. However, some patients have persistent pain and limitation of movement in the early postoperative period. No studies have investigated the combined treatment of microfracture and shortwave treatment in these patients. The aim of this prospective single-centre, randomized, double-blind, placebo-controlled trial was to compare the outcome in patients treated with arthroscopic microfracture combined with radial extracorporeal shockwave therapy (rESWT) and arthroscopic microfracture alone, in patients with ostechondritis of the talus.

Methods

Patients were randomly enrolled into two groups. At three weeks postoperatively, the rESWT group was given shockwave treatment, once every other day, for five treatments. In the control group the head of the device which delivered the treatment had no energy output. The two groups were evaluated before surgery and at six weeks and three, six and 12 months postoperatively. The primary outcome measure was the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. Secondary outcome measures included a visual analogue scale (VAS) score for pain and the area of bone marrow oedema of the talus as identified on sagittal fat suppression sequence MRI scans.

Results

A total of 40 patients were enrolled and randomly divided into the two groups, with 20 in each. There was no statistically significant difference in the baseline characteristics of the groups. No complications, such as wound infection or neurovascular injury, were found during follow-up of 12 months. The mean AOFAS scores in the rESWT group were significantly higher than those in the control group at three, six, and 12 months postoperatively (p < 0.05). The mean VAS pain scores in the rESWT group were also significantly lower than those in the control group at these times (p < 0.05). The mean area of bone marrow oedema in the rESWT group was significantly smaller at six and 12 months than in the control group at these times (p < 0.05).

Conclusion

Local shockwave therapy was safe and effective in patients with osteochondiritis of the talus who were treated with a combination of arthroscopic surgery and rESWT. Preliminary results showed that, compared with arthroscopic microfracture alone, those treated with arthroscopic microfracture combined with rESWT had better relief of pain at three months postoperatively and improved weightbearing and motor function of the ankle.

Presurgical and Postsurgical MRI Evaluation of Osteochondral Lesions of the Foot and Ankle: A Primer

The gold standard diagnostic imaging tool for ankle OCLs is magnetic resonance imaging, which allows precise evaluation of the articular cartilage and assessment of the surrounding soft tissue structures. Post-operative morphologic MRI assessment via MOCART scores provide semi-quantitative analysis of the repair tissue, but mixed evidence exists regarding its association with post-operative outcomes. Post-operative biochemical MRIs allow assessment of the collagen network of the articular cartilage via T2-mapping and T2∗ mapping, and assessment of the articular glycosaminoglycan content via delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T1rho mapping and sodium imaging.

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.

Dual-tissue transplantation versus osteochondral autograft transplantation in the treatment of osteochondral defects: a porcine model study

BACKGROUND

Osteochondral injury is a common sports injury, and hyaline cartilage does not regenerate spontaneously when injured. However, there is currently no gold standard for treating osteochondral defects. Osteochondral autograft transplantation (OAT) is widely used in clinical practice and is best used to treat small osteochondral lesions in the knee that are < 2 cm² in size. Autologous dual-tissue transplantation (ADTT) is a promising method with wider indications for osteochondral injuries; however, ADTT has not been evaluated in many studies. This study aimed to compare the radiographic and histological results of ADTT and OAT for treating osteochondral defects in a porcine model.

METHODS

Osteochondral defects were made in the bilateral medial condyles of the knees of 12 Dian-nan small-ear pigs. The 24 knees were divided into the ADTT group (n = 8), OAT group (n = 8), and empty control group (n = 8). At 2 and 4 months postoperatively, the knees underwent gross evaluation based on the International Cartilage Repair Society (ICRS) score, radiographic assessment based on CT findings and the magnetic resonance observation of cartilage repair tissue (MOCART) score, and histological evaluation based on the O'Driscoll histological score of the repair tissue.

RESULTS

At 2 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score were significantly better in the OAT group than the ADTT group (all P < 0.05). At 4 months postoperatively, the ICRS score, CT evaluation, MOCART score, and O'Driscoll histological score tended to be better in the OAT group than the ADTT group, but these differences did not reach statistical significance (all P > 0.05).

CONCLUSIONS

In a porcine model, ADTT and OAT are both effective treatments for osteochondral defects in weight bearing areas. ADTT may be useful as an alternative procedure to OAT for treating osteochondral defects.

Osteochondral Lesions of the Ankle and Foot

Osteochondral lesions (OCLs) in the ankle are more common than OCLs of the foot, but both share a similar imaging appearance. Knowledge of the various imaging modalities, as well as available surgical techniques, is important for radiologists. We discuss radiographs, ultrasonography, computed tomography, single-photon emission computed tomography/computed tomography, and magnetic resonance imaging to evaluate OCLs. In addition, various surgical techniques used to treat OCLs-debridement, retrograde drilling, microfracture, micronized cartilage-augmented microfracture, autografts, and allografts-are described with an emphasis on postoperative appearance following these techniques.

The role of imaging in osteoarthritis

Osteoarthritis is a complex whole-organ disorder that involves molecular, anatomic, and physiologic derangement. Advances in imaging techniques have expanded the role of imaging in evaluating osteoarthritis and functional changes. Radiography, magnetic resonance imaging, computed tomography (CT), and ultrasonography are commonly used imaging modalities, each with advantages and limitations in evaluating osteoarthritis. Radiography comprehensively analyses alignment and osseous features, while MRI provides detailed information about cartilage damage, bone marrow edema, synovitis, and soft tissue abnormalities. Compositional imaging derives quantitative data for detecting cartilage and tendon degeneration before structural damage occurs. Ultrasonography permits real-time scanning and dynamic joint evaluation, whereas CT is useful for assessing final osseous detail. Imaging plays an essential role in the diagnosis, management, and research of osteoarthritis. The use of imaging can help differentiate osteoarthritis from other diseases with similar symptoms, and recent advances in deep learning have made the acquisition, management, and interpretation of imaging data more efficient and accurate. Imaging is useful in monitoring and predicting the prognosis of osteoarthritis, expanding our understanding of its pathophysiology. Ultimately, this enables early detection and personalized medicine for patients with osteoarthritis. This article reviews the current state of imaging in osteoarthritis, focusing on the strengths and limitations of various imaging modalities, and introduces advanced techniques, including deep learning, applied in clinical practice.

Retrograde Drilling, Ossoscopy, and Autologous Bone Grafting: An Alternative Technique for Treatment of Osteochondral Lesion of the Talus Stage 2 and 3 in Adults

BACKGROUND

Symptomatic osteochondral lesions of the talus (OLTs) often require surgical intervention. There are various surgical methods. A generally valid, stage-dependent therapeutic algorithm does not exist. The aim of our study is to show long- term results of an alternative technique that combines retrograde drilling, debridement performed under arthroscopic visualization, and autologous bone grafting.

METHODS

The surgical technique was performed in 24 patients with medial or lateral OLTs, and the data were analyzed retrospectively. In our technique, the affected subchondral bone was overdrilled retrogradely and resected under arthroscopic visualization (ossoscopy) without violating the cartilage. The resulting defect was filled with autologous bone from the medial tibia metaphysis. Outcome parameters were the numeric rating scale (NRS), the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, and range of motion (ROM). The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was assessed and a possible correlation with the clinical outcome scores was calculated. Data concerning complication rates were also collected.

RESULTS

The mean surface size of the OLTs was 0.9 ± 0.3 cm2. The mean follow-up was 89 months. The AOFAS score improved significantly from 57.7 points preoperatively to 88.8 points at the final follow-up (P < .0001). The pain value measured by the NRS decreased significantly from 8 to a pain level of 2. ROM improved in 37.5% of the patients for dorsiflexion and 29.2% for plantarflexion. There were no significant correlations between the MOCART score and the AOFAS score or the pain value on NRS.

CONCLUSION

Retrograde drilling, ossoscopy, and autologous bone grafting for OLTs is a promising technique with good long-term results. The patients' satisfaction rate, especially in OLT stages 2 and 3, was excellent.

LEVEL OF EVIDENCE

Level IV, case series.

Injectable autologous chondrocyte implantation in acetabular cartilage defects: 2-year minimum clinical and MRI results

INTRODUCTION

Early results using injectable autologous chondrocyte implantation (ACI) for the treatment of full thickness acetabular cartilage defects have been promising. However, so far there is no information on radiological results after injectable ACI using spheroids. The purpose of this sturdy was to (1) investigate the quality of tissue repair on MRI and (2) investigate the correlation between the MRI results and clinical results at a minimum follow-up of 24 months after third generation ACI in full thickness acetabular cartilage defects. It was hypothesized that ACI shows good MRI results in patients with large full thickness acetabular cartilage defects 24 months after surgery. It was also hypothesized that there is a correlation between postoperative clinical and MRI morphological results at a minimum follow-up of 24 months.

STUDY DESIGN

Retrospective case series.

MATERIALS AND METHODS

Patients with ACI for full thickness acetabular cartilage defects > 2 cm² were evaluated by preoperative and postoperative clinical scoring tools including the modified Harris Hip Score (mHHS), the International Hip Outcome Tool (iHOT-33), and the Subjective Hip Value (SHV) as well as a high resolution indirect arthro-MRI 24 months after surgery utilizing an identical imaging protocol for all patients. The magnetic resonance observation of cartilage repair tissue (MOCART) scoring system was used to classify the repair tissue on MRI. Demographic patient data was evaluated for influencing factors for pre- and postoperative clinical as well as radiological results.

RESULTS

Thirty six consecutive patients (5 women/31 men, average age 32.9 years) had undergone two stage ACI procedure. The average size of the cartilage defect was 5.0 (2-6) cm². The average follow-up was 29.9 (24-42) months. Four patients were not available for the final follow-up (follow-up rate 89%). The postoperative average MOCART score was 82.2 (± 14.2). MOCART score showed medium correlation of the item defect fill and the postoperative mHHS (r = 0.384, p = 0.043). There was no correlation of the other items or the total score with postoperative results. The patients showed significant improvement in the outcome measurements between preoperative and postoperative in the mHHS, the iHOT-33, and the SHV.

CONCLUSIONS

Despite the large acetabular cartilage defects included in this study, ACI showed good MRI results with complete defect fill in 87.5% after a minimum 24-month follow-up. Statistically significant correlation of MRI and clinical results could only be seen with the item defect fill. Further research with longer follow-up is needed to evaluate the long-term results of ACI in acetabular cartilage defects.

A Randomized Trial of Autologous Chondrocyte Implantation Versus Alternative Forms of Surgical Cartilage Management in Patients With a Failed Primary Treatment for Chondral or Osteochondral Defects in the Knee

BACKGROUND

There are limited randomized controlled trials with long-term outcomes comparing autologous chondrocyte implantation (ACI) versus alternative forms of surgical cartilage management within the knee.

PURPOSE

To determine at 5 years after surgery whether ACI was superior to alternative forms of cartilage management in patients after a failed previous treatment for chondral or osteochondral defects in the knee.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

In total, 390 participants were randomly assigned to receive either ACI or alternative management. Patients aged 18 to 55 years with one or two symptomatic cartilage defects who had failed 1 previous therapeutic surgical procedure in excess of 6 months prior were included. Dual primary outcome measures were used: (1) patient-completed Lysholm knee score and (2) time from surgery to cessation of treatment benefit. Secondary outcome measures included International Knee Documentation Committee and Cincinnati Knee Rating System scores, as well as number of serious adverse events. Analysis was performed on an intention-to-treat basis.

RESULTS

Lysholm scores were improved by 1 year in both groups (15.4 points [95% CI, 11.9 to 18.8] and 15.2 points [95% CI, 11.6 to 18.9]) for ACI and alternative, with this improvement sustained over the duration of the trial. However, no evidence of a difference was found between the groups at 5 years (2.9 points; 95% CI, -1.8 to 7.5; P = .46). Approximately half of the participants (55%; 95% CI, 47% to 64% with ACI) were still experiencing benefit at 5 years, with time to cessation of treatment benefit similar in both groups (hazard ratio, 0.97; 95% CI, 0.72 to 1.32; P > .99). There was a differential effect on Lysholm scores in patients without previous marrow stimulation compared with those with marrow stimulation (P = .03; 6.4 points in favor of ACI; 95% CI, -0.4 to 13.1). More participants experienced a serious adverse event with ACI (P = .02).

CONCLUSION

Over 5 years, there was no evidence of a difference in Lysholm scores between ACI and alternative management in patients who had previously failed treatment. Previous marrow stimulation had a detrimental effect on the outcome of ACI.

REGISTRATION

International Standard Randomised Controlled Trial Number: 48911177.

Mosaicplasty With High Tibial Osteotomy for Knee Subchondral Insufficiency Fracture Had Better Magnetic Resonance Observation of Cartilage Repair Tissue Scores With Less Bone Marrow Edema and Better Plug Union and Less Plug Necrosis Compared With Mosaicplasty Alone

PURPOSE

To determine the magnetic resonance imaging (MRI) findings after mosaicplasty (MOS) for knee subchondral insufficiency fracture (SIFK), and to analyze the relationship between MRI findings and clinical outcomes.

METHODS

We retrospectively reviewed the cases of consecutive patients who underwent MOS for SIFK with/without high tibial osteotomy (HTO) between January 1998 and December 2015. The MRI findings at 12 months after the surgery were assessed by the modified magnetic resonance observation of cartilage repair tissue (MOCART) score to determine the degree of bone marrow edema (BME), plug union, and plug necrosis. The clinical outcomes were assessed by Lysholm score to clarify the minimal clinically important difference (MCID) and patient acceptable symptom state analysis.

RESULTS

In total, 58 patients (17 men and 41 women) were enrolled in this study. Among them, 30 knees were treated by MOS alone and 28 knees were treated by MOS with HTO. The MOCART scores of patients who received MOS alone were significantly lower in BME score (P = .0060), plug union score (P = .0216), and in plug necrosis score (P = .0326) than patients who received MOS with HTO. BME lesion was less likely to persist among elderly (odds ratio 1.20, P = .0248) and female (OR 41.8, P = .0118) patients. The MCID of Lysholm score was 6.6 in MOS alone and 8.4 in MOS with HTO cases, but there were no significant association between MRI findings and the postoperative Lysholm score.

CONCLUSIONS

The MOS with HTO cases had better MOCART scores with less BME, better plug union, and less plug necrosis compared with MOS alone cases. Female and older patients had better resolution of BME, but there was no significant correlation between MRI findings and the postoperative Lysholm score. All cases in both groups showed improvement of Lysholm score exceeding MCID; thus, MOS may be effective as a joint preserving surgery for SIFK.

LEVEL OF EVIDENCE

Level IV, clinical case series.

Multilayered biomimetic scaffolds for cartilage repair of the talus. A systematic review of the literature

OBJECTIVE

The aim of the present review was to analyze the available evidence in the literature on the clinical and radiological outcomes of multilayered biomimetic scaffolds in the treatment of osteochondral lesions of the talus (OLTs).

DESIGN

A systematic search was performed in three databases to identify clinical trials, where the multilayered biomimetic scaffolds were used for the treatment of OLTs. The PRISMA guidelines were followed. Qualitative analysis of the relevant data of the included studies was executed. The methodological quality of the analyzed studies was assessed with a modified Coleman Methodology Score (CMS).

RESULTS

A total of 10 studies with 87 patients were included in the analysis. Only three multilayered biomimetic scaffolds have been investigated in clinical trials for the treatment of OLTs. The worst clinical and radiological outcomes, as well as safety profile were observed for the TruFit scaffold (Smith & Nephew, Andover, MA, USA), which had already been withdrawn from the market. The other two scaffolds (MaioRegen, Finceramica, Italy; Agili-C, Cartiheal, Israel) performed significantly better in the majority of the reviewed studies, especially in the clinical aspect. The radiological findings, the improvements of MOCART scores, the completeness of lesions' fill, and the structure of regenerated tissue were much more inconsistent.

CONCLUSIONS

Two of the multilayered biomimetic scaffolds demonstrated an adequate potential in the treatment of complex OLTs. However, limited studies availability and their low level of medical evidence request further high-level investigations before the clinical decision making for such scaffolds in the treatment of OLTs can be defined.

Fixation of Unstable Femoral Juvenile Osteochondritis Dissecans Lesions with Bioabsorbable Pins-Clinical and Radiographic Outcomes

Juvenile Osteochondritis Dissecans (JOCD) is a common reason for knee pain among children. The aim of this case study was to report on clinical and radiographic outcomes after fixation of an osteochondral fragment with bioabsorbable pins in children with open growth plates. We hypothesized that surgical treatment with this technique will result in good function, high rates of radiographic healing and high return to sport rates. A total of 13 knees in 12 patients (6 male, 6 female) with a median of 13 years (11, 17) were evaluated retrospectively at a minimum clinical follow-up of 24 months. Inclusion criteria were defined as open growth plates and an unstable osteochondral lesion grade III or IV. The clinical outcome was evaluated utilizing three standardized patient-reported outcome scores (Tegner Activity Scale [TAS], Knee Injury and Osteoarthritis Outcome Score [KOOS], Lysholm Score). All patients underwent magnetic resonance imaging 15 months (3, 34) after surgical treatment and defect healing was evaluated utilizing a modified version of the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Due to the small sample size, the data was reported descriptively. The interobserver variability was calculated with the Spearman rank correlation coefficient. Comparisons were made with Wilcoxon sign rank test (or sign test). At final follow-up the median KOOS Score was 98% (79.2%, 100%) and the median Lysholm Score was 94 (69, 100) points. The Tegner Activity Scale was 7 (4, 10) points preoperatively and 7 (4,10) points postoperatively (p = 0.5). Complete bony ingrowth occurred in 9 knees (69%), complete cartilage defect repair in 10 knees (77%) and integration to the border zone was found in 11 knees (85%) 15 (3, 34) months following surgical treatment. Fixation of osteochondral fragments with bioabsorbable pins resulted in good functional and radiographic outcomes, a high return to sport- and a low complication rate among children with open growth plates.

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.

Can the MRI based AMADEUS score accurately assess pre-surgery chondral defect severity according to the ICRS arthroscopic classification system?

Purpose

The AMADEUS (Area Measurement And DEpth and Underlying Structures) scoring and grading system has been proposed for the MRI based evaluation of untreated focal chondral defects around the knee. The clinical practicability, its correlation with arthroscopically assessed grading systems (ICRS – International Cartilage Repair Society) and thereby its clinical value in terms of decision making and guiding prognosis was yet to determine.

Methods

From 2008 to 2019 a total of 89 individuals were indicated for high tibial valgus osteotomy (HTO) due to tibial varus deformity and concomitant chondral defects of the medial compartment of the knee. All patients received a preoperative MRI (1.5 Tesla or 3.0 Tesla) and pre-osteotomy diagnostic arthroscopy. Chondral defects of the medial compartment were scored and graded with the MRI based AMADEUS by three independent raters and compared to arthroscopic defect grading by the ICRS system. Interrater and intrarater reliability as well as correlation analysis with the ICRS classification system were assessed.

Results

Intraclass correlation coefficients for the various subscores of the AMADEUS showed an overall good to excellent interrater agreement (min: 0.26, max: 0.80). Intrarater agreement turned out to be substantially inferior (min: 0.08, max: 0.53). Spearman correlation revealed an overall moderate correlative association of the AMADEUS subscores with the ICRS classification system, apart from the defect area subscore. Sensitivity of the AMADEUS to accurately identify defect severity according to the ICRS was 0.7 (0.69 for 3.0 Tesla MRI, 0.67 for 1.5 Tesla MRI). The mean AMADEUS grade was 2.60 ± 0.81 and the mean ICRS score 2.90 ± 0.63.

Conclusions

Overall, the AMADEUS with all its subscores shows moderate correlation with the arthroscopic chondral grading system according to ICRS. This suggests that chondral defect grading by means of the MRI based AMADEUS is well capable of influencing and guiding treatment decisions. Interrater reliability shows overall good agreement.

Osteochondral Fractures in Acute Patellar Dislocations in Adolescents: Midterm Results of Surgical Treatment

Background:

Osteochondral fractures (OCFs) are common injuries during acute patellar dislocation (APD), carrying a high risk of early joint deterioration if left untreated. The recommended approach is reduction and stable fixation; however, data on the results of such treatment are limited.

Purpose:

To evaluate midterm results of fixation of APD-related OCFs in adolescents and to identify predictive factors for poor outcomes.

Study Design:

Case series; Level of evidence, 4.

Methods:

This was a retrospective analysis of adolescent patients who underwent internal fixation of APD-related OCFs between 2004 and 2015 at a single tertiary pediatric trauma center. The primary outcome variables included Knee injury and Osteoarthritis Outcome Score (KOOS), patient satisfaction (0-10 scale), and sports participation compared with preoperative level. Secondary outcome variables included relationship between final results and OCF location (patellofemoral vs tibiofemoral), surgical delay (>6 weeks), and patellar instability after OCF fixation. OCF healing was evaluated using magnetic resonance imaging (MRI).

Results:

Included were 40 patients (19 female, 21 male) with 42 OCFs (29 patellar OCFs, 13 lateral femoral condyle OCFs). The median patient age at surgery was 14.5 years (interquartile range [IQR], 13-15.5 years), and median follow-up was 76 months (IQR, 52.5-95 months). Recurrence of patellar instability occurred in 27.5% of patients. Median overall KOOS was 93.8 (IQR, 90.8-97.6); KOOS–Symptoms, 92.9 (IQR, 85.7-96.4); KOOS–Pain, 97.2 (IQR, 91.7-100); KOOS–Activities of Daily Living, 100 (IQR, 97.1-100); KOOS–Sports, 90 (IQR, 80-100); and KOOS–Quality of Life, 78.1 (IQR, 56.2-87.5). Median satisfaction score was 8 (IQR, 8-9), and 16 patients (40%) returned to sports participation at their preinjury level. MRI scans revealed a 100% rate of bone healing. Abnormalities exceeding the fracture area were evident on MRI scans in 86.5% of patients. Recurrence of patellar instability (even after surgical fixation) and unstable patella at final follow-up were independent predictors of worse results after OCF fixation.

Conclusion:

In the current study, reduction and internal fixation for APD-related OCF in adolescents yielded favorable midterm outcomes. Recurrence of dislocation and persistent patellar instability jeopardized clinical results.

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.

Postoperative Ankle Imaging, 2022

Postoperative ankle imaging requires knowledge of the underlying surgical techniques, the usefulness of various imaging modalities, as well as an appreciation for the desired clinical outcomes. Surgical procedures discussed in this article are tibiotalar fracture fixation, tibiotalar, subtalar, and tibiotalocalcaneal arthrodesis, total ankle arthroplasty, talar osteochondral lesion repair and grafting, lateral ligamentous repair and reconstruction, and peroneal and Achilles tendon repair and reconstruction. Imaging can play a vital role in determining if the expected outcome has been achieved and identifying complications, with particular emphasis placed on the use of radiographs, computed tomography (including weight-bearing), magnetic resonance imaging, and ultrasonography.

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.

Mesenchymal Stem Cell Exosomes Promote Functional Osteochondral Repair in a Clinically Relevant Porcine Model

BACKGROUND

Previous studies have reported the efficacy of human mesenchymal stem cell (MSC) exosomes for the repair of osteochondral defects in rats and rabbits. However, the safety and efficacy of MSC exosomes remain to be validated in a clinically relevant large animal model.

PURPOSE

To validate the safety and efficacy of human MSC exosomes for osteochondral repair in a clinically relevant micropig model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Bilateral osteochondral defects (6-mm diameter and 1-mm depth) were surgically created in the medial femoral condyles in knees of 12 micropigs. The pigs then received 2-mL intra-articular injections of MSC exosomes and hyaluronic acid (HA) (Exosome+HA) or HA alone after surgery and thereafter at 8 and 15 days. Osteochondral repair was assessed by magnetic resonance imaging (MRI) at 15 days and at 2 and 4 months after surgery as well as by macroscopic, histological, biomechanical, and micro-computed tomography (micro-CT) analyses at 4 months after surgery.

RESULTS

Exosome+HA-treated defects demonstrated significantly better MRI scores than HA-treated defects at 15 days and at 2 and 4 months. Additionally, Exosome+HA-treated defects demonstrated functional cartilage and subchondral bone repair, with significantly better macroscopic and histological scores and biomechanical properties (Young modulus and stiffness) than HA-treated defects at 4 months. Micro-CT further showed significantly higher bone volume and trabecular thickness in the subchondral bone of Exosome+HA-treated defects than that of HA-treated defects. Importantly, no adverse response or major systemic alteration was observed in any of the animals.

CONCLUSION

This study shows that the combination of MSC exosomes and HA administered at a clinically acceptable frequency of 3 weekly intra-articular injections can promote functional cartilage and subchondral bone repair, with significantly improved morphological, histological, and biomechanical outcomes in a clinically relevant porcine model.

CLINICAL RELEVANCE

Our findings provide a robust scientific rationale to support a phase 1/2 clinical trial to test MSC exosomes in patients with osteochondral lesions.

The Role of Mesenchymal Stromal Cells in the Management of Knee Chondral Defects

➤

Mesenchymal stromal cells (MSCs) are a subset of progenitor cells that help to promote tissue healing and regeneration through the secretion of various cytokines and growth factors. Although technically pluripotent, MSCs in vivo rarely repair damaged tissue through direct differentiation and engraftment.

➤

Augmentation of traditional marrow stimulation techniques with MSCs has been theorized to improve repair tissue quality and defect fill. Clinical trials evaluating this technique are limited but have shown modest improvements compared with isolated marrow stimulation.

➤

Various scaffolds also have been utilized in combination with MSCs to treat focal chondral defects. Although the techniques described are heterogeneous, many have shown promising early clinical outcomes.

➤

Newer techniques involving 3-dimensional bioprinted scaffolds seeded with MSCs allow for the recreation of complex architecture, more closely resembling articular cartilage. These techniques are evolving and have not yet been studied in human clinical trials.

The Effect of Autologous Adipose-Derived Stromal Vascular Fractions on Cartilage Regeneration Was Quantitatively Evaluated Based on the 3D-FS-SPGR Sequence: A Clinical Trial Study

Background

Numerous reports confirmed the safety and clinical efficacy of autologous adipose-derived stromal vascular fractions (SVF), which have recently been used to treat osteoarthritis (OA). However, there is still no consensus as to whether SVF can promote cartilage regeneration. Herein, the purpose of our study was to evaluate the effectiveness of SVF versus hyaluronic acid (HA) in cartilage regeneration by establishing a cartilage model based on the three-dimensional fat-suppressed spoiled gradient recalled echo (3D-FS-SPGR) sequence.

Methods

Patients with symptomatic OA were recruited in our research, who were randomized into two groups. Meanwhile, patients in Kellgren-Lawrence (K-L) grades 2 and 3 were distinguished in each group. In the test group, patients received SVF injections of the knee, while patients in the control group received the same dose of HA. Each patient underwent the 3D-FS-SPGR sequence to establish a cartilage model at baseline, 6 months, and 12 months, respectively. The cartilage was characterized into six regions, and relevant parameters of the cartilage model were counted. Clinical and radiographic scores were recorded in one-year follow-up.

Results

In all regions, the thickness and volume of cartilage defect and the volume of healthy cartilage were improved to some extent in the test group, especially the medial femoral condyle (MF) and medial tibial condyle (MT). In grades 2 and 3, the thickness and volume of cartilage defect decreased by 0.92 ± 0.18 mm and 1.03 ± 0.23 mm and 84.00 ± 32.30 mm³ and 130.30 ± 49.56 mm³ in MF and by 0.96 ± 0.22 mm and 0.99 ± 0.14 mm and 64.18 ± 21.40 mm³ and 95.11 ± 19.93 mm³ in MT, respectively. No such phenomenon was observed in the control group. Meanwhile, the SVF-treated knees showed significant improvement in clinical and radiographic scores at 12 months. Nevertheless, these scores of the control group became worse at 12-month follow-up visit.

Conclusion

Taken together, this study shows that intra-articular injection of SVF markedly improved the clinical symptoms without adverse events, thereby repairing the damaged articular cartilage through cartilage regeneration.

Magnetic Resonance Imaging Assessment of Cartilage Appearance Following Marrow Stimulation of Osteochondritis Dissecans of the Humeral Capitellum

PURPOSE

Osteochondritis dissecans (OCD) of the capitellum is often treated by marrow stimulation techniques with good long-term outcomes. Magnetic resonance imaging (MRI) can be used to characterize the healing of cartilage repair tissue. However, no formal system exists for assessment of cartilage healing after marrow stimulation in capitellar OCD. The aims of this study were to describe the postoperative MRI appearance of capitellar repair cartilage after debridement and marrow stimulation for capitellar OCD and assess differences between symptomatic and asymptomatic patients.

METHODS

This was a retrospective study of patients with capitellar OCD who underwent arthroscopic debridement and marrow stimulation and had a postoperative MRI to assess healing. The classification system developed by Marlovits and colleagues (Magnetic Resonance Observation of Cartilage Repair Tissue) was used to quantitatively profile the cartilage repair tissue in comparison to adjacent "normal" cartilage. Study participants completed an online survey to correlate outcomes with cartilage appearance.

RESULTS

Eleven patients who underwent MRI for routine evaluation (asymptomatic), and 18 who underwent MRI for symptoms were identified. Overall, 59% of defects were completely filled, and in 83%, the cartilage surface had ulcerations or fibrillations. The cartilage variables were similar between symptomatic and asymptomatic patients. Capitellar subchondral bone edema was observed on the MRI of every patient who underwent a reoperation and was present in only 62% of those who did not. Clinical scores did not correlate with MRI cartilage findings, but the small sample size limited conclusions regarding clinical outcomes related to postoperative cartilage features seen on MRI.

CONCLUSIONS

This detailed assessment of cartilage appearance by MRI after marrow stimulation for capitellar OCD demonstrated that incomplete cartilage fill was common in both symptomatic and asymptomatic patients. Those requiring a second surgery were more likely to demonstrate subchondral bone edema.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

Outcomes of Autologous Osteochondral Transplantation With and Without Extracellular Matrix Cartilage Allograft Augmentation for Osteochondral Lesions of the Talus

BACKGROUND

Autologous osteochondral transplantation (AOT) using a cylindrical graft in the treatment of osteochondral lesions of the talus (OLTs) is typically indicated for patients with larger lesions. However, with lesions that are irregular in shape, the AOT graft may not completely replace the lesion. For these lesions, we utilize extracellular matrix cartilage allograft (EMCA) augmentation in AOT to act as a physiologic grout at the host-graft interface.

PURPOSE

To determine if the combination of EMCA with concentrated bone marrow aspirate (CBMA) would improve integration of the host-graft interface and subsequently reduce postoperative cyst formation after AOT. It was also hypothesized that EMCA in conjunction with CBMA would demonstrate improved MOCART (magnetic resonance observation of cartilage repair tissue) scores and functional outcome scores at a minimum 2 years after surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was performed comparing patients treated with AOT/CBMA alone and AOT with CBMA/EMCA. Clinical outcomes were evaluated with the Foot and Ankle Outcome Score. Magnetic resonance imaging appearance was evaluated with the use of the MOCART (magnetic resonance observation of cartilage repair tissue) score. Cyst formation was also evaluated on postoperative magnetic resonance imaging.

RESULTS

A total of 26 patients were included in the AOT + CBMA/EMCA group (10 male, 16 female), and 34 patients were included in the AOT/CBMA group (17 male, 17 female). The mean Foot and Ankle Outcome Score significantly improved in both groups (P < .001) across all subscales (symptoms, pain, activities of daily living, sports activities, and quality of life), but there was no significant difference between groups at final follow-up. There was no significant difference in mean MOCART scores between the groups (P = .118). In the AOT/CBMA group, 3 patients (8.8%) complained of knee pain, and 1 (2.9%) required additional surgery (hardware removal). In the AOT + CBMA/EMCA group, 2 patients (7.7%) complained of knee pain, and 6 patients (23%) required additional surgery (3 hardware removals and 3 arthroscopic debridements of scar tissue in the ankle).

CONCLUSION

We found that while EMCA with CBMA has benefit in regeneration and repair of OLT treated with bone marrow stimulation, there appears to be little benefit of EMCA over CBMA alone as a physiologic grout at the graft-host interface in OLT treated with AOT.

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.

Adipose Tissue-Derived Mesenchymal Stem Cells as a Potential Restorative Treatment for Cartilage Defects: A PRISMA Review and Meta-Analysis

Cartilage defects are a predisposing factor for osteoarthritis. Conventional therapies are mostly palliative and there is an interest in developing newer therapies that target the disease’s progression. Mesenchymal stem cells (MSCs) have been suggested as a promising therapy to restore hyaline cartilage to cartilage defects, though the optimal cell source has remained under investigation. A PRISMA systematic review was conducted utilising five databases (MEDLINE, EMBASE, Cochrane Library, Scopus, Web of Science) which identified nineteen human studies that used adipose tissue-derived MSC (AMSC)-based therapies, including culture-expanded AMSCs and stromal vascular fraction, to treat cartilage defects. Clinical, imaging and histological outcomes, as well as other relevant details pertaining to cartilage regeneration, were extracted from each study. Pooled analysis revealed a significant improvement in WOMAC scores (mean difference: −25.52; 95%CI (−30.93, −20.10); p < 0.001), VAS scores (mean difference: −3.30; 95%CI (−3.72, −2.89); p < 0.001), KOOS scores and end point MOCART score (mean: 68.12; 95%CI (62.18, 74.05)), thus showing improvement. The studies in this review demonstrate the safety and efficacy of AMSC-based therapies for cartilage defects. Establishing standardised methods for MSC extraction and delivery, and performing studies with long follow-up should enable future high-quality research to provide the evidence needed to bring AMSC-based therapies into the market.

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.

Effect of Graft-Host Interference Fit on Graft Integration after Osteochondral Allograft Transplantation: A Comparative MRI Analysis of Two Instrumentation Sets

OBJECTIVE

Precise graft-host interference fit is a potentially import factor for the successful incorporation of osteochondral allograft (OCA) transplants for the treatment of symptomatic focal cartilage defects. It was hypothesized that selection of OCA plug instrumentation set has a significant effect on graft integration and morphology after OCA transplantation.

METHODS

Thirty-one patients who underwent OCA transplantation between July 2013 and July 2016 were identified for this comparative magnetic resonance imaging (MRI) analysis. Patients were stratified into two groups based on the treatment with the Arthrex Allograft OATS Instrument Set or the JRF Ortho Osteochondral Allograft Plug Instrumentation. MRI was obtained at 12 months postoperatively. All grafts were assessed for integration using the Osteochondral Allograft MRI Scoring System (OCAMRISS), host marrow edema size, graft-host interface distance, graft cartilage integrity, cyst size, graft contour and presence of effusion.

RESULTS

At a mean follow-up of 11.39 ± 1.98 months, 95.5% of all grafts showed osseous integration into the recipient bone with 68.2% presenting without cystic changes of the graft or host-graft junction. No differences were seen in any OCAMRISS subscale besides cartilage signal, which demonstrated minimal differences (P = 0.046).

CONCLUSION

OCAs show excellent osseous integration at the graft-host junction at 12 months postoperatively. The comparative MRI analysis of two instrumentation sets yielded no significant differences in terms of graft integration, bone marrow edema, or cystic formation. Hence, this study cannot recommend one instrumentation set over the other. Consequently, the individual preference should guide the surgeon's selection of instrumentation for OCA transplantation.

Chondral and Osteochondral Femoral Cartilage Lesions Treated with GelrinC: Significant Improvement of Radiological Outcome Over Time and Zonal Variation of the Repair Tissue Based on T2 Mapping at 24 Months

OBJECTIVE

To prospectively assess the efficacy of GelrinC in the treatment of chondral and osteochondral femoral cartilage lesions using morphological (Magnetic Resonance Observation of Cartilage Repair Tissue [MOCART]) and quantitative (T₂-mapping) magnetic resonance imaging (MRI).

DESIGN

This study was designed as a prospective single-arm, open label, multicenter study. Morphological magnetic resonance imaging (MRI) for MOCART assessment and T₂ mapping was performed 1 week and 6, 12, 18, and 24 months after GelrinC implantation. Evaluation of T₂ mapping was based on the assessment of global T₂ indices (T₂ of the repair tissue [RT] divided by T₂ of healthy reference cartilage) and zonal variation.

RESULTS

Fifty-six (20 female) patients were prospectively enrolled. The mean MOCART score significantly increased from baseline to the 24-month follow-up with 88.8 (95% CI, 85.8-91.9; P < 0.001) for all lesions combined as well as 86.8 (95% CI, 83.0-90.6) for chondral lesions and 94.1 (95% CI, 68.55-100) for osteochondral lesions. Furthermore, based on T₂ mapping, significant zonal variation of the RT was observed at 24 months (P = 0.039), which did not differ significantly from healthy reference cartilage (P = 0.6).

CONCLUSION

Increasing MOCART scores were observed throughout the follow-up period, indicative of maturation of the cartilage repair. Significant zonal variation of the RT at 24 months might indicate the transformation into hyaline cartilage-like RT. Slightly differing morphological outcome between chondral and osteochondral lesions, but similar global and zonal T₂ indices at 24 months, support the potential of GelrinC as a treatment option for both lesion types.

Biomechanical Changes of Repair Tissue after Autologous Chondrocyte Implantation at Long-Term Follow-Up

Objective. This study aims to describe biomechanical maturation process of repair tissue after cartilage repair with autologous chondrocyte implantation (ACI) at long-term follow-up. Design. After ACI, 40 patients underwent altogether 60 arthroscopic biomechanical measurements of the repair tissue at various time points during an up to 11-year follow-up period. Of these patients, 30 patients had full-thickness cartilage lesions and 10 had an osteochondritis dissecans (OCD) defect. The mean lesion area was 6.5 cm² (SD 3.2). A relative indentation stiffness value for each individually measured lesion was calculated as a ratio of repair tissue and surrounding cartilage indentation value to enable interindividual comparison. Results. Repair tissue stiffness improved during approximately 5 years after surgery. Most of the increase in stiffness occurred during the first 2 years. The curvilinear correlation between relative stiffness values and the follow-up time was 0.31 (95% CI 0.07-0.52), P = 0.017. The interindividual variation of the stiffness was high. Lesion properties or demographic factors showed no significant correlation to biomechanical outcome. The overall postoperative average relative stiffness was 0.75 (SD 0.47). Conclusions. Our clinical study describes a biomechanical maturation process of cartilage repair that may continue even longer than expected. A substantial increase in tissue stiffness proceeds for the first two years postoperatively. Minor progression proceeds for even longer. In some repairs, the biomechanical result was equal to native cartilage, suggesting hyaline-type repair. The variation in biomechanical results suggests substantial inconsistency in the structural outcome following ACI.

Costal Chondrocyte-Derived Pellet-Type Autologous Chondrocyte Implantation versus Microfracture for Repair of Articular Cartilage Defects: A Prospective Randomized Trial

OBJECTIVE

To compare the efficacy and safety of costal chondrocyte-derived pellet-type autologous chondrocyte implantation (CCP-ACI) with microfracture (MFx) for repair of articular cartilage defects of the knee.

DESIGN

Thirty subjects with an International Cartilage Repair Society (ICRS) grade 3 to 4 chondral defect (2-10 cm² in area; ≤4 cm³ in volume) were randomized at a ratio of 2:1 (CCP-ACI:MFx). Twenty patients were allocated in the CCP-ACI group and 10 patients in the MFx group. CCP-ACI was performed by harvesting costal cartilage at least 4 weeks before surgery. Implantation was performed without any marrow stimulation. Efficacy and safety were assessed at weeks 8, 24, and 48 after surgery according to the magnetic resonance observation of cartilage repair tissue (MOCART) score and clinical outcomes.

RESULTS

MOCART scores improved from baseline to 24 and 48 weeks postoperatively in both treatment groups. The improvement in MOCART scores in the CCP-ACI group was significantly greater than that in the MFx group at 24 and 48 weeks (39.1 vs 21.8 and 43.0 vs 24.8, respectively). The proportions of complete defect repair and complete integration were significantly higher in the CCP-ACI group than the MFx group at 48 weeks. Improvement in Lysholm score and KOOS subscores, including Function (Sports and Recreational Activity) and knee-related quality of life was significantly greater in the CCP-ACI group than the MFx group at 48 weeks (35.4 vs 31.5, 35.7 vs 28.5, and 27.9 vs 11.6, respectively).

CONCLUSION

Treatment of cartilage defects with CCP-ACI yielded satisfactory cartilage tissue repair outcomes, with good structural integration with native cartilage tissue shown by magnetic resonance imaging at 24 and 48 weeks after surgery.

LEVEL OF EVIDENCE

Level 1: Randomized controlled study.

The Role of Hypertension in Cartilage Restoration: Increased Failure Rate After Autologous Chondrocyte Implantation but Not After Osteochondral Allograft Transplantation

Objectives. The purpose of this study was to examine whether patients with diagnosed hypertension have an increased risk of graft failure following cartilage repair with either autologous chondrocyte implantation (ACI) or osteochondral allograft transplantation (OCA). We hypothesized that hypertension is related to higher ACI and OCA graft failure. Design. Patients who underwent ACI or OCA transplantation between February 2009 and December 2016 were included in this study. Inclusion criteria were (1) at least 2 years' follow-up, (2) available information related to the living habits (smoking and medication status), and (3) available information related to the presence of hypertension, diabetes mellitus, or hyperlipidemia. To identify potential independent risk factors of graft failure, univariate screening was performed and factors with significance at a level of P < 0.1 were entered in multivariate logistic regression models. Results. A total of 368 patients (209 ACI and 159 OCA) were included into our study. In the ACI group, 61 patients' (29.1%) graft failed. Univariate screening identified older age, female gender, defect size, higher prevalence of hypertension, and smoking as a predictor of graft failure. Following, multivariate logistic regression revealed female gender (odds ratio [OR] 1.02, P = 0.048), defect size (OR 1.07, P = 0.035), and hypertension (OR 3.73, P = 0.023) as significant independent risk factors predicting graft failure after ACI. In the OCA group, 29 patients' (18.2%) graft failed and none of the included factors demonstrated to be a potential risk factor for graft failure. Conclusion. Hypertension, defect size, and female gender seem to predict ACI graft failure but not OCA failure.

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.

An accelerated 6-week return to full weight bearing after matrix-induced autologous chondrocyte implantation results in good clinical outcomes to 5 years post-surgery

PURPOSE

To investigate the mid-term outcomes of an accelerated return to full weight bearing (WB) after matrix-induced autologous chondrocyte implantation (MACI).

METHODS

This randomized study allocated 35 patients (37 knees) to a 6 week (n = 18) or 8 week (n = 19) return to full WB after MACI. Patients were evaluated pre-operatively and at 1, 2 and minimum 5 years (range 5.5-7 years), using the KOOS, SF-36, visual analogue pain scale, 6-min walk test and active knee range of motion (ROM). Peak isokinetic knee extensor and flexor strength was assessed, with limb symmetry indices (LSIs) calculated. Magnetic resonance imaging (MRI) was undertaken to evaluate the repair tissue, and an MRI composite score was calculated.

RESULTS

While no group differences (n.s.) were observed, significant improvement was observed for all patient-reported outcome measures (p < 0.05), 6-min walk distance (p = 0.040), active knee flexion (p = 0.002) and extension (p < 0.0001) ROM, and the LSI for peak knee extensor strength (p < 0.0001). At final review, 87.5% (6 weeks) and 82.4% (8 weeks) of patients were satisfied overall. A non-significant decline (n.s.) was observed for the MRI composite score from 1-year post-surgery to final review, with no significant MRI-based differences (n.s.) between groups. At final review, two grafts (6-week n = 1, 8-week n = 1) demonstrated MRI-based graft failure, while an additional patient had progressed toward knee arthroplasty (8.1% failure rate at minimum 5 years).

CONCLUSIONS

The 6-week return to full WB after MACI provided comparable clinical and MRI-based outcomes beyond 5 years post-surgery, without jeopardizing the graft. This 6-week WB protocol is faster than those previously proposed and studied.

LEVEL OF EVIDENCE

II.

Mesenchymal Stem Cells in the Treatment of Cartilage Defects of the Knee: A Systematic Review of the Clinical Outcomes

BACKGROUND

Osteochondral lesions are a common clinical problem and their management has been historically challenging. Mesenchymal stem cells have the potential to differentiate into chondrocytes and thus restore hyaline cartilage to the defect, theoretically improving clincal outcomes in these patients. They can also be harvested with minimal donor site morbidity.

PURPOSE

To assess the clinical and functional outcomes of mesenchymal stem cell implantation to treat isolated osteochondral defects of the knee. A secondary purpose is to assess the quality of the current available evidence as well as the radiological and histological outcomes. We also reviewed the cellular preparation and operative techniques for implantation.

STUDY DESIGN

Systematic review.

METHODS

A comprehensive literature search of 4 databases was carried out: CINAHL, Embase, MEDLINE, and PubMed. We searched for clinical studies reporting the outcomes on a minimum of 5 patients with at least 12 months of follow-up. Clinical, radiological, and histological outcomes were recorded. We also recorded demographics, stem cell source, culture technique, and operative technique. Methodological quality of each study was assessed using the modified Coleman methodology score, and risk of bias for the randomized controlled studies was assessed using the Cochrane Collaboration tool.

RESULTS

Seventeen studies were found, encompassing 367 patients. The mean patient age was 35.1 years. Bone marrow was the most common source of stem cells utilized. Mesenchymal stem cell therapy consistently demonstrated good short- to medium-term outcomes in the studies reviewed with no serious adverse events being recorded. There was significant heterogeneity in cell harvesting and preparation as well as in the reporting of outcomes.

CONCLUSION

Mesenchymal stem cells demonstrated a clinically relevant improvement in outcomes in patients with osteochondral defects of the knee. More research is needed to establish an optimal treatment protocol, long-term outcomes, and superiority over other therapies.

REGISTRATION

CRD42020179391 (PROSPERO).

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.

Intra-articular injection of orthobiologics in patients undergoing high tibial osteotomy for knee osteoarthritis is safe and effective - a systematic review

Purpose

To qualitatively evaluate the current evidence reporting outcomes of intra-articular injection of orthobiologics in patients undergoing high tibial osteotomy (HTO) for osteoarthritis of the knee.

Methods

A systematic search methodology of the PUBMED, EMBASE, and CINAHL databases was conducted in July 2021. The search workflow was in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The following inclusion criteria were adopted: clinical trials of any level of evidence, reporting outcomes following intra-articular injection of orthobiologics during high tibial osteotomy for knee osteoarthritis, with a minimum number of 10 patients treated. Duplicate data, studies on implanted orthobiologics and articles not written in English were excluded from this review.

Results

Eight studies were included in this review, with a total of 585 patients. Outcomes were discussed based on the types of orthobiologics used: (i) Platelet-Rich Plasma (PRP), (ii) Bone Marrow Aspirate Concentrate (BMAC), and (iii) Injected Mesenchymal Stem Cells (MSCs). Two studies utilised PRP, 4 studies utilised BMAC and 4 studies utilised injected MSCs.. Three studies provided Level II evidence and five studies provided Level III evidence. Statistically significant improvements in outcomes were documented in multiple trials, with few patients experiencing adverse events.

Conclusion

Intra-articular injection of orthobiologics in patients undergoing HTO is safe and effective with good outcomes reported. Due to the lack of high-level evidence, further research is required before this can be considered standard of care.

Level of evidence

III

Short-term radiological results after spheroid-based autologous chondrocyte implantation in the knee are independent of defect localisation

BACKGROUND

Lesions of articular cartilage represent a crucial risk factor for the early development of osteoarthritis. Autologous chondrocyte implantation (ACI) is a well-established procedure in therapy of those lesions in the knee. The aim of the presented study is to detect differences in short-term radiological outcome depending on defect localization (femoral condyle vs. retropatellar) after spheroid-based ACI.

OBJECTIVE

This study aimed to demonstrate that radiological outcome after spheroid-based ACI in the knee is independent of defect localization.

METHODS

MRI-scans after retropatellar ACI and ACI of the medial/lateral femoral condyle, with a preoperative Outerbridge grade of III or IV were evaluated regarding MOCART 2.0.

RESULTS

The mean defect-size was 5.0 ± 1.8 cm2, with a minimum size of 2 cm2 and a maximum size of 9 cm2. Scans were performed 7.7 months (± 3.1 months) postoperatively. The mean MOCART 2.0 score was 78.5 ± 15.6. No statistically significant influence neither of the localization (p= 0.159), the gender (p= 0.124) nor defect size (< 5 cm2 vs. ⩾ 5 cm2; p= 0.201) could be observed.

CONCLUSIONS

The presented data demonstrate good to excellent radiological short-term results after spheroid-based ACI. Data indicates, that at least radiological results are independent of gender, defect-size and defect-localization.

Correlation between the subchondral bone marrow lesions and cartilage repair tissue after matrix-associated autologous chondrocyte implantation in the knee: a cross-sectional study

BACKGROUND

The contribution of the subchondral bone in the development and progression of osteoarthritis (OA) has long been recognized, but its role in cartilage repair procedures has only recently attracted more attention.

PURPOSE

To explore the correlation between the cartilage repair tissue (RT) and the subchondral bone marrow lesions (BMLs) after matrix-associated autologous chondrocyte implantation (MACI) in the knee joint.

MATERIAL AND METHODS

A total of 30 patients who underwent MACI in the knee from January 2015 to June 2018 and follow-up magnetic resonance imaging (MRI) scan were recruited in this study. The MRI results of cartilage RT were evaluated using T2* relaxation time. Subchondral BMLs were also qualitatively evaluated by use of the two-dimensional proton density-weighted fat-suppressed (2D-PD-FS) and three-dimensional dual-echo steady-state (3D-DESS) sequences.

RESULTS

The univariate analysis displayed a significant negative correlation between subchondral BMLs and cartilage RT (P < 0.01). In the minimally adjusted model (only age, sex, and body mass index [BMI] adjusted), the results did not show obvious changes (β = -6.54, 95% confidence interval [CI] = -10.99 to -2.09; P = 0.008). After adjustment for the full models (age, sex, BMI, defect size, combined injury, and preoperative duration of symptoms adjusted), the connection was also detected (β = -6.66, 95% CI -11.82 to -1.50; P = 0.019).

CONCLUSION

After MACI, the subchondral BMLs are significantly correlated with cartilage RT-T₂* relaxation time. The role of subchondral bone in cartilage repair procedures should not be underestimated.