Matrix-induced autologous chondrocyte implantation of the knee: mid-term and long-term follow-up by MR arthrography

Clinical and Radiological Outcomes at ≥10-Year Follow-up After Matrix-induced Autologous Chondrocyte Implantation in the Patellofemoral Joint

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of knee cartilage defects, although limited research is available on its longer term (≥10 years) sustainability in the patellofemoral joint.

PURPOSE

To report the clinical and radiological outcomes at ≥10 years in a prospectively recruited cohort of patients undergoing MACI in the patellofemoral joint and compare outcomes in patients undergoing MACI on the patella versus the trochlea.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The current study prospectively enrolled 95 patients who underwent patellofemoral MACI, of whom 29 (13 patella, 16 trochlea) underwent concomitant tibial tubercle osteotomy. Patients were assessed preoperatively and at 2, 5, and ≥10 years using a range of patient-reported outcome measures (PROMs) including the Knee injury and Osteoarthritis Outcome Score, the 36-item Short Form Health Survey, and the frequency and severity of knee pain as well as patient satisfaction, full active knee flexion and extension, and peak isokinetic knee extensor and flexor torques. High-resolution magnetic resonance imaging (MRI) was performed to assess pertinent graft parameters, as well as determine an overall MRI composite score, per the Magnetic Resonance Observation of Cartilage Repair Tissue scoring system. Results were analyzed according to the graft location (patella or trochlea).

RESULTS

Of the 95 patients recruited, 82 patients (41 patella, 41 trochlea) were available for a clinical review at ≥10 years after surgery (mean follow-up, 11.9 years [range, 10-15 years]). For the whole patellofemoral MACI cohort, all PROMs significantly improved over time (P < .05), with no significant changes (P > .05) observed in any MRI-based score from 2 to ≥10 years after surgery. At ≥10 years, 90.2% (n = 74) were satisfied with MACI in relieving their knee pain, and 85.4% (n = 70) were satisfied with the improvement in their ability to participate in sports. No differences (P > .05) were observed in PROMs between those undergoing patellar MACI and those undergoing trochlear MACI, although a significant group effect was observed for limb symmetry indices of knee extensor (P = .009) and flexor (P = .041) strength, which were greater in those undergoing patellar (vs trochlear) MACI. No statistically significant differences (P > .05) were observed between patellar and trochlear grafts on any MRI-based measure. In the cohort assessed at ≥10 years after surgery, 4 patients (2 patella, 2 trochlea) demonstrated graft failure on MRI scans, although a further 3 patients (all trochlea) were omitted from the ≥10-year review for having already progressed to total knee arthroplasty.

CONCLUSION

Good clinical scores, high levels of patient satisfaction, and adequate graft survivorship were observed at ≥10 years after MACI on the patella and trochlea.

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.

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

Treatment of Cartilage Defects of the Knee in Military Tactical Athletes: An Overview of Management and Clinical Outcomes

Cartilage defects of the knee are a common problem that can be caused by trauma or chronic repetitive overload and result in debilitating functional limitations. These consequences are of particular significance to military service members, who, by in large, are a group of young, active individuals with professional duties requiring full, unrestricted activity and function. The burden of knee chondral-related disease among military tactical athletes is well established, and systematic approach to the evaluation of a military member with suspected knee chondral pathology facilitates the execution of a surgical procedure that maximizes the likelihood of a return to duty. Despite advances in cartilage restoration surgery, chondral pathology of the knee remains a vexing problem and an omnipresent threat to military medical readiness and warfighter lethality.

Efficacy and safety of CARTIGROW® in patients with articular cartilage defects of the knee joint: a four year prospective studys

Introduction

Research shows autologous chondrocyte implantation (ACI) is a promising treatment for articular cartilage lesions. In this study, we assessed mid-term efficacy and safety of gel-based ACI or autologous adult live cultured chondrocytes (CARTIGROW®) implantation in patients with cartilage defects of the knee joint.

Methods

In this prospective, open-label study, patients (19–38 years) with focal, international cartilage repair society grade III or IV articular cartilage defects of the knee joint were enroled at four centres across India from April 2015 to September 2015. Punch biopsy was conducted to harvest cartilage, from which chondrocytes were isolated and cultured, and the characterised chondrocytes were implanted into the cartilage defect. Key efficacy outcomes were assessed by quantitative changes in international knee documentation committee (IKDC), visual analogue scale (VAS) scores, and qualitative changes in magnetic resonance imaging at six months and four years from baseline.

Results

Of the14 patients enroled in the study, all patients completed the six month follow-up and 11 completed the four year follow-up. The IKDC score improved significantly from 32.84 ± 9.25 at baseline to 67.49 ± 13.03 at six months (mean difference [MD] 34.66 ± 13.00, p < 0.0001) and to 60.18 ± 10.33 at four years (MD 28.21 ± 15.14, p = 0.0001). The VAS score reduced from 72.00 ± 14.40 at baseline to 16.64 ± 17.03 at six months (MD 55.36 ± 24.50, p < 0.0001) and further to 12.72 ± 9.05 at four years (MD 62.09 ± 10.66, p < 0.0001). All patients showed improvement on MRI of the knee joint. No adverse events were reported.

Conclusion

Autologous adult live cultured chondrocytes (CARTIGROW®) implantation showed good mid-term efficacy in patients with cartilage defects of the knee joint with no side-effects.

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.

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.

Decellularized sturgeon cartilage extracellular matrix scaffold inhibits chondrocyte hypertrophy in vitro and in vivo

Since chondrocyte hypertrophy greatly limits the efficiency of cartilage defects repairing via cartilage tissue engineering (CTE), it is critical to develop a functional CTE scaffold able to inhibit chondrocyte hypertrophy during this period of cartilage regeneration. In this study, we tested the applicability of using decellularized sturgeon cartilage ECM (dSCECM) scaffold to cease chondrocyte hypertrophy during cartilage damage repair. The dSCECM scaffolds with interconnected porous structure and pore size of 114.1 ± 20.9 μm were successfully prepared with freeze-dry method. Chondrocytes displayed a round shape and aggregated to form cellular spheroids within dSCECM scaffolds, which is similar to their chondrocytic phenotype within cartilage in vivo. Higher transcriptional level of chondrogenic related genes and integrin related genes was observed in chondrocytes incubated with dSCECM scaffolds instead of type I collagen (COL I) scaffolds, which were used as the control due to their widely usage in CTE and clinic applications. Furthermore, it confirmed that, compared with COL I scaffolds, dSCECM scaffolds significantly reduced the transcription of chondrocyte hypertrophy related genes in chondrocytes following the hypertrophic induction treatment. To test the ability of dSCECM scaffold to inhibit chondrocytes hypertrophy in vivo, chondrocytes with dSCECM scaffolds and COL I scaffolds were cultured with hypertrophic media and were implanted into nude mice respectively. Following 4 weeks implantation, interestingly, only the specimens derived from COL I scaffolds displayed consequences of chondrocyte hypertrophy like calcification deposition, demonstrating that chondrocyte hypertrophy is ceased by the dSCECM scaffold following hypertrophic induction. It suggests that the dSCECM scaffold can be potentially applied in clinical treating cartilage defects via the CTE approach to avoid the risk of chondrocyte hypertrophy.

Long-term Prospective Clinical and Magnetic Resonance Imaging-Based Evaluation of Matrix-Induced Autologous Chondrocyte Implantation

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging midterm clinical outcomes, although published studies presenting longer-term clinical and radiological outcomes, across varied tibiofemoral and patellofemoral graft locations, are scarce.

PURPOSE

To present the clinical and radiological outcomes a minimum of 10 years after surgery in a consecutive series of patients who underwent MACI in the tibiofemoral or patellofemoral knee joint. Secondly, to investigate any association between outcomes and patient characteristics, graft parameters, and injury and surgery history.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Overall, 87 patients (99 grafts: 57 medial femoral condyle, 24 lateral femoral condyle, 11 trochlea, 7 patella) were prospectively evaluated clinically and with magnetic resonance imaging (MRI) before surgery and at 2, 5, and minimum 10 years after MACI (mean, 13.1 years; range, 10.5-16 years). Patients were evaluated with a range of patient-reported outcome measures (PROMs), including the Knee injury and Osteoarthritis Outcome Score (KOOS) and patient satisfaction. The 6-minute walk test, active knee range of motion, and peak isokinetic knee extensor and flexor strength were assessed. Limb symmetry indices (LSIs) were calculated for strength measures. MRI was undertaken to evaluate the repair tissue, and an MRI composite score was calculated.

RESULTS

All PROMs significantly improved (P < .05) over the pre- to postoperative period. Apart from KOOS Sport (P = .018) and the LSI for peak isokinetic knee extensor strength (P = .005), which significantly improved, no significant change (P > .05) was observed from 2 years after surgery to final follow-up (range, 10.5-16 years) in all other PROMs, 6-minute walk distance, active knee range of motion, and the LSI for peak isokinetic knee flexor strength. At final follow-up, while the mean LSIs for peak isokinetic knee flexor and extensor strength were 96.9% and 95.7%, respectively, 74.7% of patients were satisfied with their ability to participate in sports, and 88.5% were satisfied overall. A nonsignificant decline was observed for tissue infill (P = .211) and the MRI composite score (P = .099) from 2 years to final review. At final MRI review, 9 grafts (9.1%) had failed. While no significant association (P > .05) was observed between clinical or MRI-based outcomes and patient demographics (age, body weight, body mass index), defect size, or the duration of preoperative symptoms, the number of previous surgical procedures was significantly and negatively associated with KOOS Symptoms (P = .015), KOOS Sport (P = .011), and the degree of tissue infill (P = .045).

CONCLUSION

MACI provided high levels of satisfaction and adequate graft survivorship as visualized on MRI at 10.5 to 16 years after surgery.

Quantitative 3-T Magnetic Resonance Imaging After Matrix-Associated Autologous Chondrocyte Implantation With Autologous Bone Grafting of the Knee: The Importance of Subchondral Bone Parameters

BACKGROUND

Matrix-associated autologous chondrocyte implantation (MACI) with autologous bone grafting (ABG) is an effective surgical treatment for osteochondral defects. Quantitative magnetic resonance imaging (MRI) techniques are increasingly applied as noninvasive biomarkers to assess the biochemical composition of cartilage repair tissue.

PURPOSE

To evaluate the association of quantitative MRI parameters of cartilage repair tissue and subchondral bone marrow with magnetic resonance morphologic and clinical outcomes after MACI with ABG of the knee.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Qualitative and quantitative 3 T MRI of the knee was performed in 21 patients (16 male) at 2.5 years after MACI with ABG at the medial (18/21) or lateral (3/21) femoral condyle for the treatment of osteochondral defects. Morphologic MRI sequences were assessed using MOCART (magnetic resonance observation of cartilage repair tissue) 2.0 scores. T2 relaxation time measurements for the assessment of cartilage repair tissue (CRT2) were obtained. Single-voxel magnetic resonance spectroscopy was performed in underlying subchondral bone marrow (BM) and at both central femoral condyles. The presence of pain and Tegner scores were noted. Statistical analyses included Student t tests, correlation analyses, and multivariate regression models.

RESULTS

The mean defect size was 4.9 ± 1.9 cm². At a follow-up of 2.5 ± 0.3 years, 9 of 21 patients were asymptomatic. Perfect defect filling was achieved in 66.7% (14/21) of patients. MOCART 2.0 scores (74.1 ± 18.4) did not indicate pain (68.3 ± 19.0 [pain] vs 81.7 ± 15.4 [no pain]; P = .102). However, knee pain was present in 85.7% (6/7) of patients with deep bony defects (odds ratio, 8.0; P = .078). Relative CRT2 was higher in hypertrophic cartilage repair tissue than in repair tissue with normal filling (1.54 ± 0.42 vs 1.13 ± 0.21, respectively; P = .022). The underlying BM edema-like lesion (BMEL) volume was larger in patients with underfilling compared with patients with perfect defect filling (1.87 ± 1.32 vs 0.31 ± 0.51 cm³, respectively; P = .002). Patients with severe pain showed a higher BMEL volume (1.2 ± 1.3 vs 0.2 ± 0.4 cm³, respectively; P = .046) and had a higher BM water fraction (26.0% ± 12.3% vs 8.6% ± 8.1%, respectively; P = .026) than did patients without pain.

CONCLUSION

Qualitative and quantitative MRI parameters including the presence of subchondral defects, CRT2, BMEL volume, and BM water fraction were correlated with cartilage repair tissue quality and clinical symptoms. Therefore, the integrity of subchondral bone was associated with outcomes after osteochondral transplantation.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Cartilage T2 Relaxation Times and Subchondral Trabecular Bone Parameters Predict Morphological Outcome After Matrix-Associated Autologous Chondrocyte Implantation With Autologous Bone Grafting

BACKGROUND

Quantitative magnetic resonance (MR) imaging techniques are established for evaluation of cartilage composition and trabecular bone microstructure at the knee. It remains unclear whether quantitative MR parameters predict the midterm morphological outcome after matrix-associated chondrocyte implantation (MACI) with autologous bone grafting (ABG).

PURPOSE

To assess longitudinal changes and associations of the biochemical composition of cartilage repair tissue, the subchondral bone architecture, and morphological knee joint abnormalities on 3-T MR imaging after MACI with ABG at the knee.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Knees of 18 patients (28.7 ± 8.4 years [mean ± SD]; 5 women) were examined preoperatively and 3, 6, 12, and 24 months after MACI and ABG using 3-T MR imaging. Cartilage composition was assessed using T₂ relaxation time measurements. Subchondral bone microstructure was quantified using a 3-dimensional phase-cycled balanced steady-state free precision sequence. Trabecular bone parameters were calculated using a dual threshold algorithm (apparent bone fraction, apparent trabecular number, and apparent trabecular separation). Morphological abnormalities were assessed using the MOCART (magnetic resonace observation of cartilage repair tissue) score, the WORMS (Whole-Organ Magnetic Resonance Imaging Score), and the CROAKS (Cartilage Repair Osteoarthritis Knee Score). Clinical symptoms were assessed using the Tegner activity and Lysholm knee scores. Statistical analyses were performed by using multiple linear regression analysis.

RESULTS

Total WORMS (P = .02) and MOCART (P = .001) scores significantly improved over 24 months after MACI. Clinical symptoms were significantly associated with the presence of bone marrow edema pattern abnormalities 24 months after surgery (P = .035). Overall there was a good to excellent radiological outcome found after 24 months (MOCART score, 88.8 ± 10.1). Cartilage repair T₂ values significantly decreased between 12 and 24 months after MACI (P = .009). Lower global T₂ values after 3 months were significantly associated with better MOCART scores after 24 months (P = .04). Moreover, trabecular bone parameters after 3 months were significantly associated with the total WORMS after 24 months (apparent bone fraction, P = .048; apparent trabecular number, P = .013; apparent trabecular separation, P = .013).

CONCLUSION

After MACI with ABG, early postoperative quantitative assessment of biochemical composition of cartilage and microstructure of subchondral bone may predict the outcome after 24 months. The perioperative global joint cartilage matrix quality is essential for proper proliferation of the repair tissue, reflected by MOCART scores. The subchondral bone quality of the ABG site is essential for proper maturation of the cartilage repair tissue, reflected by cartilage T₂ values.

Minimum 10-Year Clinical and Radiological Outcomes of a Randomized Controlled Trial Evaluating 2 Different Approaches to Full Weightbearing After Matrix-Induced Autologous Chondrocyte Implantation

BACKGROUND

Longer term outcomes after matrix-induced autologous chondrocyte implantation (MACI) are lacking, while early postoperative weightbearing (WB) management has traditionally been conservative.

PURPOSE

To investigate the longer term clinical and radiological outcomes after an 8-week (vs 12-week) WB protocol after MACI.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A randomized study design allocated 70 patients to an 8- (n = 34) or 12-week (n = 36) approach to full WB after MACI of the medial or lateral femoral condyle. Patients were evaluated preoperatively; at 3, 12, and 24 months after surgery; and at 5 and 10 years after surgery. At 10 years (range, 10.5-11.5 years), 60 patients (85.7%; 8 weeks: n = 29; 12 weeks: n = 31) were available for review. Clinical outcomes included patient-reported outcomes, maximal isokinetic knee extensor and flexor strength, and functional hop capacity. High-resolution magnetic resonance imaging (MRI) was undertaken to assess the quality and quantity of repair tissue per the MOCART (magnetic resonance observation of cartilage repair tissue) system. A combined MRI composite score was also evaluated.

RESULTS

Clinical and MRI-based scores for the full cohort significantly improved (P < .05) over the 10-year period. Apart from the Tegner activity score, which improved (P = .041), as well as tissue structure (P = .030), which deteriorated, there were no further statistically significant changes (P > .05) from 5 to 10 years. There were no 10-year differences between the 2 WB rehabilitation groups. At 10 years, 81.5% and 82.8% of patients in the 8- and 12-week groups, respectively, demonstrated good-excellent tissue infill. Graft failure was observed on MRI at 10 years in 7 patients overall, which included 4 located on 10-year MRI (8 weeks: n = 1; 12 weeks: n = 3) and a further 3 patients (8 weeks: n = 1; 12 weeks: n = 2) not included in the current analysis who proceeded to total knee arthroplasty. At 10 years, 93.3% of patients were satisfied with MACI for relieving their pain, with 83.3% satisfied with their ability to participate in sport.

CONCLUSION

MACI provided high satisfaction levels and tissue durability beyond 10 years. The outcomes of this randomized trial demonstrate a safe 8-week WB rehabilitation protocol without jeopardizing longer term outcomes.

T2-relaxation time of cartilage repair tissue is associated with bone remodeling after spongiosa-augmented matrix-associated autologous chondrocyte implantation

OBJECTIVE

To investigate whether T2 relaxation time measurements of cartilage repair tissue and structural changes of the knee joint are associated with subchondral bone architecture after spongiosa-augmented matrix-associated autologous chondrocyte implantation (MACI).

DESIGN

Both knees of 25 patients (25.5 ± 7.8y; 10 women) were examined preoperatively and 2.7 years after unilateral spongiosa-augmented MACI with 3T magnetic resonance (MR) imaging. Cartilage composition was assessed using T2 relaxation time measurements, subchondral trabecular bone microstructure was quantified using a 3D phase-cycled balanced steady state free-precision sequence. Structural knee joint changes were assessed using the modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was used for the postoperative description of the area that underwent MACI. Correlations were assessed using Spearman's rank correlation coefficients.

RESULTS

Hypertrophy of the cartilage repair tissue was found in 2 of 25 patients, both after a MACI procedure at the patella, 21 patients showed congruent filling. In subchondral bone of the cartilage repair compartment, apparent trabecular thickness was significantly higher in compartments with elevated cartilage T2 (n = 17; 0.37 ± 0.05 mm) compared to those showing no difference in cartilage T2 compared to the same compartment in the contralateral knee (n = 8; 0.27 ± 0.05 mm; P = 0.042). Significant correlations were found between the overall progression of WORMS and the ipsilateral vs contralateral ratio of average trabecular thickness (r = 0.48, P = 0.031) and bone fraction (r = 0.57, P = 0.007).

CONCLUSIONS

After spongiosa-augmented MACI, T2 values of cartilage repair tissue and structural knee joint changes correlated with the quality of the underlying trabecular bone.

Osteochondral autograft transplantation for isolated patellofemoral osteoarthritis

BACKGROUND

The purpose of this retrospective study was to evaluate clinical outcomes of osteochondral autograft transplantation (OAT) for isolated patellofemoral (PF) osteoarthritis (OA).

METHODS

OAT was performed in seven patients (six men, one woman; mean age, 61.1years) with isolated PF OA. The mean duration of follow up was 46.9months (range, 24-84months). Clinical outcomes were evaluated preoperatively and postoperatively according to the International Knee Documentation Committee (IKDC) objective score and the knee scoring system of the Japanese Orthopaedic Association (JOA) score. The International Cartilage Repair Society (ICRS) score was recorded in three cases that underwent second-look arthroscopies postoperatively. For morphological evaluation, the Kellgren and Lawrence (KL) classification and the modified magnetic resonance observation of cartilage repair tissue (MOCART) score were used.

RESULTS

The mean IKDC and JOA scores were both significantly improved. The percentage of normal and nearly normal on the IKDC score was increased from 28.6% (2/7) to 85.7% (6/7) (P=0.05). The mean JOA score was improved from 80.0 (range, 65.0-85.0) to 95.0 (range, 90.0-100) (P=0.0008). The mean ICRS scores were 10.3 (nearly normal) in the three cases that underwent second-look arthroscopies postoperatively. Regarding KL classification, the grade was unchanged in five cases (two cases in grade 1, three cases in grade 2) and improved in two cases (from grade 3 to 2, from grade 4 to 3). The mean modified MOCART score was 67.9 (range, 60.0-75) at 12-month follow up. There were no complications, and satisfaction was obtained in all cases. The study design was case series: level IV.

CONCLUSIONS

All clinical scores improved significantly postoperatively. Osteochondral plugs were transplanted perpendicular to the articular surface to obtain good congruity of the repaired articular surface. In this way, OAT is an effective procedure to prevent progression of isolated PF OA.

A Comparison of 2-Year Outcomes in Patients Undergoing Tibiofemoral or Patellofemoral Matrix-Induced Autologous Chondrocyte Implantation

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging clinical results in the treatment of knee chondral defects. However, earlier studies suggested that chondrocyte implantation in the patellofemoral (PF) joint was less effective than in the tibiofemoral (TF) joint.

PURPOSE

To compare the radiological and clinical outcomes of those undergoing MACI to either the femoral condyles or PF joint.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 194 patients were included in this analysis, including 127 undergoing MACI to the medial (n = 94) and lateral (n = 33) femoral condyle, as well as 67 to the patella (n = 35) or trochlea (n = 32). All patients were evaluated clinically (Knee injury and Osteoarthritis Outcome Score [KOOS], visual analog scale, Short Form-36) before surgery and at 3, 12, and 24 months after surgery, while magnetic resonance imaging (MRI) was undertaken at 3, 12, and 24 months, with the MOCART (magnetic resonance observation of cartilage repair tissue) scoring system employed to evaluate the quality and quantity of repair tissue, as well as an MRI composite score. Patient satisfaction was evaluated.

RESULTS

No significant group differences ( P > .05) were seen in demographics, defect size, prior injury, or surgical history, while the majority of clinical scores were similar preoperatively. All clinical scores significantly improved over time ( P < .05), with a significant group effect observed for KOOS activities of daily living ( P = .008), quality of life ( P = .008), and sport ( P = .017), reflecting better postoperative scores in the TF group. While the PF group had significantly lower values at baseline for the KOOS activities of daily living and quality of life subscales, it actually displayed a similar net improvement over time compared with the TF group. At 24 months, 93.7% (n = 119) and 91.0% (n = 61) of patients were satisfied with the ability of MACI to relieve their knee pain, 74.0% (n = 94) and 65.7% (n = 44) with their ability to participate in sport, and 90.5% (n = 115) and 83.6% (n = 56) satisfied overall, in the TF and PF groups, respectively. MRI evaluation via the MOCART score revealed a significant time effect ( P < .05) for the MRI composite score and graft infill over the 24-month period. While subchondral lamina scored significantly better ( P = .002) in the TF group, subchondral bone scored significantly worse ( P < .001). At 24 months, the overall MRI composite score was classified as good/excellent in 98 TF patients (77%) and 54 PF patients (81%).

CONCLUSION

MACI in the PF joint with concurrent correction of PF maltracking if required leads to similar clinical and radiological outcomes compared with MACI on the femoral condyles.

Two-Year Outcomes of a Randomized Trial Investigating a 6-Week Return to Full Weightbearing After Matrix-Induced Autologous Chondrocyte Implantation

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in treating patients with knee cartilage defects. Postoperatively, the time required to attain full weightbearing (WB) remains conservative.

HYPOTHESIS

We hypothesized that patients would have no significant clinical or radiological differences or graft complications after an 8-week or 6-week return to full WB after MACI.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 37 knees (n = 35 patients) were randomly allocated to either an 8-week return to full WB that we considered current best practice based on the existing literature (CR group; n = 19 knees) or an accelerated 6-week WB approach (AR group; n = 18 knees). Patients were evaluated preoperatively and at 1, 2, 3, 6, 12, and 24 months after surgery, using the Knee Injury and Osteoarthritis Outcome Score, 36-Item Short Form Health Survey, visual analog pain scale, 6-minute walk test, and active knee range of motion. Isokinetic dynamometry was used to assess peak knee extension and flexion strength and limb symmetry indices (LSIs) between the operated and nonoperated limbs. Magnetic resonance imaging (MRI) was undertaken to evaluate the quality and quantity of repair tissue as well as to calculate an MRI composite score.

RESULTS

Significant improvements ( P < .05) were observed in all subjective scores, active knee flexion and extension, 6-minute capacity, peak knee extensor torque in the operated limb, and knee extensor LSI, although no group differences existed. Although knee flexor LSIs were above 100% for both groups at 12 and 24 months after surgery, LSIs for knee extensor torque at 24 months were 93.7% and 87.5% for the AR and CR groups, respectively. The MRI composite score and pertinent graft parameters significantly improved over time ( P < .05), with some superior in the AR group at 24 months. All patients in the AR group (100%) demonstrated good to excellent infill at 24 months, compared with 83% of patients in the CR group. Two cases of graft failure were observed, both in the CR group. At 24 months, 83% of patients in the CR group and 88% in the AR group were satisfied with the results of their MACI surgery.

CONCLUSION

Patients in the AR group who reduced the length of time spent ambulating on crutches produced comparable outcomes up to 24 months, without compromising graft integrity.

A Prospective Clinical and Radiological Evaluation at 5 Years After Arthroscopic Matrix-Induced Autologous Chondrocyte Implantation

BACKGROUND

While midterm outcomes after matrix-induced autologous chondrocyte implantation (MACI) are encouraging, the procedure permits an arthroscopic approach that may reduce the morbidity of arthrotomy and permit accelerated rehabilitation.

HYPOTHESIS

A significant improvement in clinical and radiological outcomes after arthroscopic MACI will exist through to 5 years after surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We prospectively evaluated the first 31 patients (15 male, 16 female) who underwent MACI via arthroscopic surgery to address symptomatic tibiofemoral chondral lesions. MACI was followed by a structured rehabilitation program in all patients. Clinical scores were administered preoperatively and at 3 and 6 months as well as 1, 2, and 5 years after surgery. These included the Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm knee scale (LKS), Tegner activity scale (TAS), visual analog scale for pain, Short Form-36 Health Survey (SF-36), active knee motion, and 6-minute walk test. Isokinetic dynamometry was used to assess peak knee extension and flexion strength and limb symmetry indices (LSIs) between the operated and nonoperated limbs. High-resolution magnetic resonance imaging (MRI) was performed at 3 months and at 1, 2, and 5 years postoperatively to evaluate graft repair as well as calculate the MRI composite score.

RESULTS

There was a significant improvement ( P < .05) in all KOOS subscale scores, LKS and TAS scores, the SF-36 physical component score, pain frequency and severity, active knee flexion and extension, and 6-minute walk distance. Isokinetic knee extension strength significantly improved, and all knee extension and flexion LSIs were above 90% (apart from peak knee extension strength at 1 year). At 5 years, 93% of patients were satisfied with MACI to relieve their pain, 90% were satisfied with improving their ability to undertake daily activities, and 80% were satisfied with the improvement in participating in sport. Graft infill ( P = .033) and the MRI composite score ( P = .028) significantly improved over time, with 90% of patients demonstrating good to excellent tissue infill at 5 years. There were 2 graft failures at 5 years after surgery.

CONCLUSION

The arthroscopically performed MACI technique demonstrated good clinical and radiological outcomes up to 5 years, with high levels of patient satisfaction.

Articular cartilage generation applying PEG-LA-DM/PEGDM copolymer hydrogels

Background

Injuries to the human native cartilage tissue are particularly problematic because cartilage has little to no ability to heal or regenerate itself. Employing a tissue engineering strategy that combines suitable cell sources and biomimetic hydrogels could be a promising alternative to achieve cartilage regeneration. However, the weak mechanical properties may be the major drawback to use fully degradable hydrogels. Besides, most of the fully degradable hydrogels degrade too fast to permit enough extracellular matrix (ECM) production for neocartilage formation. In this study, we demonstrated the feasibility of neocartilage regeneration using swine articular chondrocytes photoencapsualted into poly (ethylene glycol) dimethacrylate (PEGDM) copolymer hydrogels composed of different degradation profiles: degradable (PEG-LA-DM) and nondegradable (PEGDM) macromers in molar ratios of 50/50, 60/40, 70/30, 80/20, and 90/10.

Methods

Articular chondrocytes were isolated enzymatically from juvenile Yorkshire swine cartilage. 6 × 10⁷ cells cells were added to each milliliter of macromer/photoinitiator (I2959) solution. Nonpolymerized gel containing the cells (100 μL) was placed in cylindrical molds (4.5 mm diameter × 6.5 mm in height). The macromer/photoinitiator/chondrocyte solutions were polymerized using ultraviolet (365 nm) light at 10 mW/cm² for 10 mins. Also, an articular cartilaginous ring model was used to examine the capacity of the engineered cartilage to integrate with native cartilage. Samples in the pilot study were collected at 6 weeks. Samples in the long-term experimental groups (60/40 and 70/30) were implanted into nude mice subcutaneously and harvested at 6, 12 and 18 weeks. Additionally, cylindrical constructs that were not implanted used as time zero controls. All of the harvested specimens were examined grossly and analyzed histologically and biochemically.

Results

Histologically, the neocartilage formed in the photochemically crosslinked gels resembled native articular cartilage with chondrocytes in lacunae and surrounded by new ECM. Increases in total DNA, glycosaminoglycan, and hydroxyproline were observed over the time periods studied. The neocartilage integrated with existing native cartilage.

Conclusions

Articular cartilage generation was achieved using swine articular chondrocytes photoencapsulated in copolymer PEGDM hydrogels, and the neocartilage tissue had the ability to integrate with existing adjacent native cartilage.

Treatment of unstable osteochondritis dissecans in adults with autogenous osteochondral grafts (Mosaicplasty): long-term results

PURPOSE

the unstable osteochondritis dissecans (OCD-type II and III according to the ICRS classification) of the knee largher than > 2.5 cm(2) in adults are uncommon lesions and there is no consensus on how to treat them. Medium-term studies have reported good results using autogenous osteochondral plugs (mosaicplasty). The aim of this study is to analyze the long-term results of this technique for the treatment of unstable OCD in a selected group of adult patients.

METHODS

four patients with OCD at either one of the femoral condyles were included in this prospective study. The average age was 21.2 years (range, 18-24 years). The OCD lesions were classified as type II in three patients and type III in one patient and the average size was 3.8 cm(2) (range, 2.55-5.1 cm(2)). The lesions were treated in situ with a variable number of autogenous osteochondral plugs (Ø 4.5 mm(2)). The Modified Cincinnati, Lysholm II and Tegner scores were used for clinical and functional evaluation. Magnetic resonance arthrography (MRA) was performed before surgery and at 2, 5 and 10 years after surgery. A modified MOCART score was used to evaluate MRA findings.

RESULTS

the average follow-up duration was ten years and 6 months (range, 10-11 years). No complications occurred. At the final follow-up, all scores (clinical, functional and MOCART) improved. In all but one of the patients MRA showed complete osteochondral repair.

CONCLUSIONS

the fixation of large and unstable OCD lesions with mosaicplasty may be a good option for treating type II or III OCD lesions in adults. The advantages of this technique include stable fixation, promotion of blood supply to the base of the OCD fragment, and grafting of autologous cancellous bone that stimulates healing with preservation of the articular surface.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Prospective clinical and radiologic evaluation of patellofemoral matrix-induced autologous chondrocyte implantation

BACKGROUND

While matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of knee chondral defects, there remains little available research specifically investigating its use in the patellofemoral joint.

PURPOSE

To prospectively evaluate the clinical and radiologic outcome of MACI in the patellofemoral joint.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

In 47 consecutive patients undergoing patellofemoral MACI, clinical (Knee injury and Osteoarthritis Outcome Score, 36-Item Short Form Health Survey, visual analog scale for pain, 6-minute walk test, knee range of motion, and strength assessment) and magnetic resonance imaging (MRI) assessments were undertaken before and 3, 12, and 24 months after surgery. The MRI was performed to assess graft infill and determine an overall MRI composite score. Results were analyzed according to (1) the patient sample overall and (2) after stratification into 4 subgroups per implant location (patella or trochlea) as well as whether or not adjunct tibial tubercle transfer for patellofemoral malalignment was required.

RESULTS

The overall patient sample, as well as each of the 4 procedural subgroups, demonstrated clinically and statistically significant (P < .05) improvements over time for all clinical scores. Graft infill and the MRI composite score also demonstrated statistically significant (P < .05) improvements over time, with no evidence of a main effect for procedure group or interaction between procedure group and time. At 24 months after surgery, 40.4% (n = 19) of patients exhibited complete graft infill comparable with the adjacent native cartilage, with a further 6.4% (n = 3) demonstrating a hypertrophic graft. A further 31.9% (n = 15) of patients exhibited 50% to 100% tissue infill, and 17% (n = 8) demonstrated <50% tissue infill. Two patients (4.3%) demonstrated graft failure. At 24 months after surgery, 85% (n = 40) of patients were satisfied with the results of their MACI surgery.

CONCLUSION

These results demonstrate that MACI provides improved clinical and radiologic outcomes to 24 months in patients undergoing treatment specifically for articular cartilage defects on the patella or trochlea, with and without concurrent realignment of the extensor mechanism if required.

Cartilage tissue engineering: recent advances and perspectives from gene regulation/therapy

Diseases in articular cartilages affect millions of people. Despite the relatively simple biochemical and cellular composition of articular cartilages, the self-repair ability of cartilage is limited. Successful cartilage tissue engineering requires intricately coordinated interactions between matrerials, cells, biological factors, and phycial/mechanical factors, and still faces a multitude of challenges. This article presents an overview of the cartilage biology, current treatments, recent advances in the materials, biological factors, and cells used in cartilage tissue engineering/regeneration, with strong emphasis on the perspectives of gene regulation (e.g., microRNA) and gene therapy.

Matrix-induced autologous mesenchymal stem cell implantation versus matrix-induced autologous chondrocyte implantation in the treatment of chondral defects of the knee: a 2-year randomized study

BACKGROUND

Cell-based strategies that combine in vitro- expanded autologous chondrocytes with matrix scaffolds are currently preferred for full-thickness cartilage lesions of the knee ≥2 cm(2). Although this approach is reasonable, continuing advances in the field of cartilage repair will further expand the options available to improve outcomes.

HYPOTHESIS/PURPOSE

In the present clinical study, we compared the outcomes of matrix-induced autologous mesenchymal stem cell implantation (m-AMI) with matrix-induced autologous chondrocyte implantation (m-ACI) for the treatment of isolated chondral defects of the knee.

STUDY DESIGN

Prospective, single-site, randomized, single-blind pilot study.

METHODS

Fourteen patients with isolated full-thickness chondral lesions of the knee >2 cm(2) were randomized into two treatment groups: m-AMI and m-ACI. Outcomes were assessed pre-operatively and 3, 6, 12 and 24 months post-operatively.

RESULTS

Clinical evaluations revealed that improvement from pre-operation to 24 months post-operation occurred in both groups (p < 0.05). At all follow-up intervals, m-AMI demonstrated significantly better functional outcomes (motion deficit and straight leg raise strength) than did m-ACI (p < 0.05). At all follow-up intervals, m-AMI demonstrated significantly better subjective sub-scale scores for pain, symptoms, activities of daily living and sport and recreation of the knee injury and osteoarthritis outcome score (KOOS) than did m-ACI (p < 0.05). Additionally, m-AMI demonstrated significantly better (p < 0.05) scores than m-ACI for the quality of life sub-scale of the KOOS and visual analog scale (VAS) severity at the 6-month follow-up. The Tegner activity score and VAS frequency were not significantly different between the two groups. Graft failure was not observed on magnetic resonance imaging at the 24-month follow-up. m-AMI and m-ACI demonstrated very good-to-excellent and good-to-very good infill, respectively, with no adverse effects from the implant, regardless of the treatment.

CONCLUSION

For the treatment of isolated full-thickness chondral lesion of the knee, m-AMI can be used effectively and may potentially accelerate recovery. A larger patient cohort and follow-up supported by histological analyses are necessary to determine long-term outcomes.

Matrix-induced autologous chondrocyte implantation for the treatment of chondral defects of the knees in Chinese patients

Articular cartilage injury is the most common type of damage seen in clinical orthopedic practice. The matrix-induced autologous chondrocyte implant (MACI) was developed to repair articular cartilage with an advance on the autologous chondrocyte implant procedure. This study aimed to evaluate whether MACI is a safe and efficacious cartilage repair treatment for patients with knee cartilage lesions. The primary outcomes were the Knee Injury and Osteoarthritis Outcome Score (KOOS) domains and magnetic resonance imaging (MRI) results, compared between baseline and postoperative months 3, 6, 12, and 24. A total of 15 patients (20 knees), with an average age of 33.9 years, had a mean defect size of 4.01 cm(2). By 6-month follow-up, KOOS results demonstrated significant improvements in symptoms and knee-related quality of life. MRI showed significant improvements in four individual graft scoring parameters at 24 months postoperatively. At 24 months, 90% of MACI grafts had filled completely and 10% had good-to-excellent filling of the chondral defect. Most (95%) of the MACI grafts were isointense and 5% were slightly hyperintense. Histologic evaluation at 15 and 24 months showed predominantly hyaline cartilage in newly generated tissue. There were no postoperative complications in any patients and no adverse events related to the MACI operation. This 2-year study has confirmed that MACI is safe and effective with the advantages of a simple technique and significant clinical improvements. Further functional and mechanistic studies with longer follow-up are needed to validate the efficacy and safety of MACI in patients with articular cartilage injuries.

Degree of preoperative subchondral bone edema is not associated with pain and graft outcomes after matrix-induced autologous chondrocyte implantation

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) is an established technique for the repair of knee chondral defects. While a number of factors may affect the clinical outcome, little is known about the influence of subchondral bone abnormalities at the time of surgery on pain and graft outcomes after MACI.

PURPOSE

To investigate the association between subchondral bone marrow edema within 3 months before MACI surgery on preoperative and postoperative reported pain and symptoms as well as postoperative graft outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective study was undertaken in 56 patients undergoing MACI with clinical and radiological assessments before surgery and at 3, 12, 24, and 60 months after surgery. Patients were assessed using the Pain and Symptoms subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS). High-resolution magnetic resonance imaging (MRI) was used to evaluate the severity of preoperative subchondral bone marrow edema, while graft infill and an MRI composite graft score were evaluated after surgery via the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system. Linear regression utilizing generalized estimating equations was used to investigate the association between preoperative subchondral bone marrow edema scores and preoperative and postoperative KOOS subscores as well as postoperative MRI-based scores of graft repair.

RESULTS

The degree of preoperative subchondral bone marrow edema was not significantly associated with postoperative outcomes, whereby there was no evidence of a difference between edema subgroups over all time points for the KOOS-Pain subscore (P = .644), KOOS-Symptoms subscore (P = .475), or MRI composite score (P = .685) after adjustment for potential confounders of age, body mass index, defect size, and defect location.

CONCLUSION

No association was demonstrated between the severity of preoperative subchondral bone marrow edema with postoperative patient-reported knee pain or symptoms or postoperative graft repair assessed via MRI.

Clinical and radiological long-term outcomes after matrix-induced autologous chondrocyte transplantation: a prospective follow-up at a minimum of 10 years

BACKGROUND

It is unclear whether matrix-associated autologous chondrocyte transplantation (MACT) results in objective and subjective clinical improvements at 10 years after surgery.

HYPOTHESIS

Matrix-associated autologous chondrocyte transplantation will result in clinical and radiological improvements in patients with symptomatic, traumatic chondral defects of the knee joint.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 16 patients with chondral defects of the knee were treated with MACT between November 2000 and April 2002 and evaluated for up to 10 years after the intervention. The International Knee Documentation Committee (IKDC) form, Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner activity score, Brittberg score, Noyes sports activity rating scale, and visual analog scale (VAS) for pain as well as 3-T magnetic resonance imaging (MRI) using the magnetic resonance observation of cartilage repair tissue (MOCART) score and functional evaluation by the limb symmetry index (LSI) formed the basis of this study. The Friedman test and the Wilcoxon signed-rank test were performed for a comparison between all time points and 2 separate time points, respectively. If significant differences were revealed, a Bonferroni adjustment to the α level was applied so that P values <.007 (<.05/7) were regarded as significant in the paired comparisons.

RESULTS

Significant improvements (P < .05) from baseline to 120 months postoperatively were observed for the IKDC score (mean, 44.1 ± 26.9 to 59.0 ± 27.4), Noyes sports activity rating score (mean, 37.7 ± 30.1 to 62.1 ± 31.3), and KOOS Quality of Life and Pain subscores, whereas no statistically significant improvement was detected for the Brittberg score, Tegner activity score, or VAS score. After 5 years, a slight downward tendency of all clinical scores was evident. After 10 years, the mean MOCART score was 70.4 ± 16.1. Complete filling of the defect was observed in 73.9% of cases, and osteophytes were present in 78.3%. In 65.2% of the cases, a subchondral bone edema <1 cm was visible, whereas in 21.7% of the cases, a subchondral bone edema >1 cm was seen. The mean LSI for the single-legged hop test was 95.6% ± 16.2% and for the triple hop test for distance was 91.3% ± 12.2%. The mean VAS score for self-perceived stability was 60.2 ± 3.5 (range, 0-9.5) for the injured and 60.7 ± 3.8 (range, 0-10) for the uninjured leg. No adhesions or effusions were seen regarding the clinical and radiological outcomes.

CONCLUSION

The significantly improved results on 3 outcome measures after 10 years suggest that MACT represents a suitable option in the treatment of local cartilage defects in the knee.

Matrix-induced autologous chondrocyte implantation (MACI) for chondral defects in the patellofemoral joint

PURPOSE

Both autologous chondrocyte implantation (ACI) and tibial tubercle transfer (TTT) have been used to treat chondral defects in the patellofemoral joint resulting in clinical improvement. Our study investigates the magnetic resonance imaging (MRI) appearance of the matrix-induced autologous chondrocyte implantation (MACI) graft at 5-year follow-up to determine if it provides a durable treatment option in patients with an average age of 42 (standard deviation 11.6).

METHODS

Twenty-three patients were available for follow-up. Nine patients required realignment of the extensor mechanism with lateral release and TTT. The MRI magnetic resonance observation of cartilage repair tissue (MOCART) scoring system was used to assess the graft status. Clinical outcomes were assessed at these time periods.

RESULTS

The mean weighted MOCART composite score improved from 2.87 at 3 months to 3.39 at 5 years, indicating an intact appearance in most grafts. Graft height measured >50% of the adjacent native cartilage in 82% of patients. Clinical improvement assessed by the Knee Injury and Osteoarthritis Outcome Score, SF-36 (PCS) and the 6-minute walk test was demonstrated between pre-operative scores and final 5-year follow-up. 91% of patients would undergo MACI again. Correlation between MOCART and clinical scores were low in MACI to the patellofemoral joint. No significant difference was found in outcome between those that required realignment surgery compared with those that did not.

CONCLUSION

Patellofemoral MACI provides a durable graft on MRI assessment at 5 years with resultant clinical improvement. Further work is needed to determine which defect locations may benefit most from this procedure.

LEVEL OF EVIDENCE

IV.

Correlation Between Clinical and Radiological Outcomes After Matrix-Induced Autologous Chondrocyte Implantation in the Femoral Condyles

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) is an established technique for the repair of knee chondral defects, although the correlation between clinical and radiological outcomes after surgery is poorly understood.

PURPOSE

To determine the correlation between clinical and radiological outcomes throughout the postoperative timeline to 5 years after MACI.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

This retrospective study was undertaken in 83 patients (53 male, 30 female) with complete clinical and radiological follow-up at 1, 2, and 5 years after MACI. The mean age of patients was 38.9 years (range, 13-62 years), with a mean body mass index (BMI) of 26.6 kg/m(2) (range, 16.8-34.8 kg/m(2)), mean defect size of 3.3 cm(2) (range, 1-9 cm(2)), and mean preoperative duration of symptoms of 9.2 years (range, 1-46 years). Patients indicated for MACI in this follow-up were 13 to 65 years of age, although they were excluded if they had a BMI >35 kg/m(2), had undergone prior extensive meniscectomy, or had ongoing progressive inflammatory arthritis. Patients were assessed clinically using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Magnetic resonance imaging (MRI) was used to evaluate the graft using a 1.5-T or 3-T clinical scanner; the MRI assessment included 8 parameters of graft repair (infill, signal intensity, border integration, surface contour, structure, subchondral lamina, subchondral bone, and effusion) based on the magnetic resonance observation of cartilage repair tissue (MOCART) score as well as an MRI composite score. The degree of an association between the MRI parameters and the KOOS subscales at each postoperative time point was assessed with the Spearman correlation coefficient (SCC), and significance was determined at P < .05. Ethics approval was obtained from the appropriate hospital and university Human Research Ethics Committees, and informed consent was gathered from all patients.

RESULTS

The only MRI parameter displaying consistent evidence of an association with the KOOS subscales was effusion, with a pattern of increasing strength of correlations over time and statistically significant associations at 5 years with KOOS-Pain (SCC, 0.25; P = .020), KOOS-Activities of Daily Living (SCC, 0.26; P = .018), and KOOS-Sport (SCC, 0.32; P = .003). Apart from a significant correlation between subchondral lamina and KOOS-Sport at 1 year (SCC, 0.27; P = .016), no further significant findings were observed.

CONCLUSION

Apart from some consistent evidence of an association between the KOOS and effusion, this analysis demonstrated a limited correlative capacity between clinical and radiological outcomes up to 5 years after surgery.

Imaging of articular cartilage: current concepts

Magnetic resonance imaging (MRI) is the gold standard method for non-invasive assessment of joint cartilage, providing information on the structure, morphology and molecular composition of this tissue. There are certain minimum requirements for a MRI study of cartilage tissue: machines with a high magnetic field (> 1.5 Tesla); the use of surface coils; and the use of T2-weighted, proton density-weighted fast-spin echo (T2 FSE-DP) and 3D fat-suppressed T1-weighted gradient echo (3D-FS T1W GRE) sequences. For better contrast between the different joint structures, MR arthography is a method that can highlight minimal fibrillation or fractures of the articular surface and allow evaluation of the integrity of the native cartilage-repair tissue interface. To assess the biochemical composition of cartilage and cartilage repair tissue, various techniques have been proposed for studying proteoglycans [dGEMRIC, T1rho mapping, sodium (23Na) imaging MRI, etc.], collagen, and water distribution [T2 mapping, "magnetisation transfer contrast", diffusion-weighted imaging (DWI), and so on]. Several MRI classifications have been proposed for evaluating the processes of joint degeneration (WORMS, BLOKS, ICRS) and post-surgical maturation of repair tissue (MOCART, 3D MOCART). In the future, isotropic 3D sequences set to improve image quality and facilitate the diagnosis of disorders of articular structures adjacent to cartilage.

Is the clinical outcome after cartilage treatment affected by subchondral bone edema?

PURPOSE

Subchondral bone edema is a common finding after cartilage treatment, but its interpretation is still debated. The aim of this study is to analyse the presence of edema after matrix-assisted autologous chondrocyte transplantation (MACT) for knee cartilage lesions at different follow-up times and its correlation with the clinical outcome.

METHODS

Two hundred and forty-eight magnetic resonance imagings (MRIs) of patients treated with a hyaluronic acid-based MACT for lesions of the knee articular surface were considered. The MRIs belonged to 116 patients (mean age at surgery 28.6 ± 10.3 years, average defect size 2.4 ± 1.0 cm(2)), 57 affected by degenerative cartilage lesions, 27 traumatic and 32 were osteochondritis dissecans (OCD). MRI follow-up was performed from 6 to 108 months after treatment. Other than its presence or absence, the subchondral bone edema was evaluated using a 3-level grading considering extension and hyperintensity, and with the WORMS score edema classification. The IKDC subjective score was collected at the time of every MRI.

RESULTS

An analysis of the entire MRI group showed that edema is not constantly present through the follow-up, but presents a particular and well-defined trend. Edema was present within the first 2 years and was then markedly reduced or disappeared at 2 and 3 years (p = 0.044). Afterwards the level of edema increased again (p < 0.0005) and remained steadily present at medium/long-term follow-up. Patellar lesions presented significantly lower edema (p = 0.012), whereas OCD lesions presented more edema at all follow-up (p = 0.002) and a different trend, with an increasing level of edema over time. No correlation was found between edema and clinical outcome.

CONCLUSIONS

Edema after MACT is present during the first phases of cartilage maturation up to 2 years of follow-up, and then tends to disappear. However, after a few years, it tends to reappear. Less edema was found in the patella, whereas more edema was found in the OCD, where subchondral bone is primarily involved. Interestingly, the presence of edema was not correlated with a poorer clinical outcome. Whether this might be a prognostic factor at longer follow-up remains to be determined, but our results give some indication on what to expect on both MRI edema and clinical outcome after MACT.

LEVEL OF EVIDENCE

Case series, Level IV.

Effects of hesperidin loaded poly(lactic-co-glycolic acid) scaffolds on growth behavior of costal cartilage cells in vitro and in vivo

It has been widely accepted that costal cartilage cells (CCs) have more excellent initial proliferation capacity than articular cartilage cells. Biodegradable synthetic polymer poly(lactic-co-glycolic acid) (PLGA) was approved by Food and Drug Administration. Hesperidin has antifungal, antiviral, antioxidant, anti-inflammatory, and anticarcinogenic properties. Hesperidin loaded (0, 3, 5, and 10 wt.%) PLGA scaffolds were prepared and in vitro and in vivo properties were characterized. Scaffolds were seeded with CCs isolated from rabbit, which were kept in culture to harvest for histological analysis. Hesperidin/PLGA scaffolds were also implanted in nude mice for 7 and 28 days. Assays of 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfo-phenyl)-2H-tetrazolium, monosodium salt (WST), and scanning electron microscope were carried out to evaluate attachment and proliferation of CCs in hesperidin/PLGA scaffolds. Glycosaminoglycan assay was performed to confirm the effects of hesperidin on extracellular matrix formation. Reverse-transcriptase polymerase chain reaction was carried out to confirm the expression of the specific genes for CCs. In these results, we demonstrated that cell attachment and proliferation on hesperidin/PLGA scaffolds were more excellent compared with on PLGA scaffold. Specially, 5 wt.% hesperidin/PLGA scaffold represented the best results among other scaffolds. Thus, 5 wt.% hesperidin/PLGA scaffold will be applicable to tissue engineering cartilage.

Clinical rehabilitation guidelines for matrix-induced autologous chondrocyte implantation on the tibiofemoral joint

Autologous chondrocyte implantation (ACI) has become an established technique for the repair of full-thickness chondral defects in the knee. Matrix-induced ACI (MACI) is the third and current generation of this surgical technique, and, while postoperative rehabilitation following MACI aims to restore normal function in each patient as quickly as possible by facilitating a healing response without overloading the repair site, current published guidelines appear conservative, varied, potentially outdated, and often based on earlier ACI surgical techniques. This article reviews the existing evidence-based literature pertaining to cell loading and postoperative rehabilitation following generations of ACI. Based on this information, in combination with the technical benefits provided by third-generation MACI in comparison to its surgical predecessors, we present a rehabilitation protocol for patients undergoing MACI in the tibiofemoral joint that has now been implemented for several years by our institution in patients with MACI, with good clinical outcomes.

Implantation of matrix-induced autologous chondrocyte (MACI ®) grafts using carbon dioxide insufflation arthroscopy

PURPOSE

The purpose of this study was to determine the safety of a new arthroscopic Matrix-induced autologous chondrocyte implant (MACI) technique with carbon dioxide insufflation utilized to improve visualization during the dry phase of the scaffold implant.

METHODS

Between 2004 and 2007, thirty patients were treated for symptomatic focal chondral lesions of the medial femoral condyle. All patients were monitored during surgery for gas embolism signs and symptoms and were evaluated preoperatively and at a median follow-up of 70.5 months (range 48-93 months) using the KOOS subjective evaluation score, the Lysholm function score, the Tegner activity scale for the knee, and the IKDC objective score.

RESULTS

No cases of intraoperative or postoperative symptoms or signs related to gas embolism or persistent subcutaneous emphysema were registered. Each subscale of the KOOS subjective score improved from preoperative to follow-up. The median Lysholm score was 50 (range 15-66) at baseline and 87.5 (range 54-100) at follow-up (p < 0.05). The median Tegner score was 2 (range 1-4) at baseline to 5 (range 2-7) at follow-up (p < 0.05).

CONCLUSIONS

No complications registered, and the satisfactory clinical results achieved in this series suggest that carbon dioxide insufflation during arthroscopic MACI is a safe and accessible option to improve visualization during the dry phase of the scaffold implant on medial femoral condyles.

Influence of cell differentiation and IL-1β expression on clinical outcomes after matrix-associated chondrocyte transplantation

BACKGROUND

Several patient- and defect-specific factors influencing clinical outcomes after matrix-associated chondrocyte transplantation (MACT) have been identified, including the patient's age, location of the defect, or duration of symptoms before surgery. Little is known, however, about the influence of cell-specific characteristics on clinical results after transplantation.

PURPOSE

The aim of the present study was to investigate the influence of cell differentiation and interleukin-1 β (IL-1β) expression on clinical outcomes up to 5 years after MACT.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-seven patients who underwent MACT of the tibiofemoral joint area of the knee were included in this study. Clinical assessments were performed preoperatively as well as 6, 12, 24, and 60 months after transplantation by using the following scores: the Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Documentation Committee (IKDC) Subjective Knee Form, the Noyes sports activity rating scale, the Brittberg clinical score, and a visual analog scale (VAS) for pain. The quality of repair tissue was assessed by magnetic resonance imaging using the magnetic resonance observation of cartilage repair tissue (MOCART) score at 1 and 5 years. Cell differentiation (defined as collagen type II:type I expression ratio), aggrecan, and IL-1β expression were determined by real-time polymerase chain reaction in transplant residuals and were correlated with clinical outcomes.

RESULTS

The largest improvements in clinical scores were found during the first year. Two years postoperatively, a stable improvement was reached until 5 years after transplantation, with a mean IKDC score of 34.4 ± 8.6 preoperatively to 77.9 ± 16 after 24 months (P < .001). Cell differentiation showed a significant positive correlation with nearly all clinical scores at different time points, especially after 12 months (P < .05). IL-1β expression negatively influenced clinical outcomes at 24 months (Brittberg score) and 60 months (Brittberg and VAS scores) after surgery (P < .05). No correlation was found between the MOCART score and clinical outcomes or gene expression.

CONCLUSION

Our data demonstrate that cell differentiation and IL-1β expression influence clinical outcomes up to 5 years after MACT.

Long-term outcomes after first-generation autologous chondrocyte implantation for cartilage defects of the knee

BACKGROUND

Autologous chondrocyte implantation (ACI) represents an established surgical therapy for large cartilage defects of the knee joint. Although various studies report satisfying midterm results, little is known about long-term outcomes.

PURPOSE

To evaluate long-term clinical and magnetic resonance imaging (MRI) outcomes after ACI.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between January 1997 and June 2001, a total of 86 patients were treated with ACI for isolated cartilage defects of the knee. The mean patient age at the time of surgery was 33.3 ± 10.2 years, and the mean defect size was 6.5 ± 4.0 cm(2). Thirty-four defects were located on the medial femoral condyle and 13 on the lateral femoral condyle, while 6 patients were treated for cartilage defects of the trochlear groove and 17 for patellar lesions. At a mean follow-up of 10.9 ± 1.1 years, 70 patients (follow-up rate, 82%) treated for 82 full-thickness cartilage defects of the knee were available for an evaluation of knee function using standard instruments, while 59 of these patients were additionally evaluated by 1.5-T MRI to quantify the magnetic resonance observation of cartilage repair tissue (MOCART) score. Clinical function at follow-up was assessed by means of the Lysholm score, the International Knee Documentation Committee (IKDC) score, and the Knee injury and Osteoarthritis Outcome Score (KOOS). Patient activity was assessed by the Tegner score. In addition, pain on a visual analog scale (VAS) and patient satisfaction were evaluated separately.

RESULTS

At follow-up, 77% reported being "satisfied" or "very satisfied." The mean IKDC score at follow-up was 74.0 ± 17.3. The mean Lysholm score improved from 42.0 ± 22.5 before surgery to 71.0 ± 17.4 at follow-up (P < .01). The mean pain score on the VAS decreased from 7.2 ± 1.9 preoperatively to 2.1 ± 2.1 postoperatively. The mean MOCART score was 44.9 ± 23.6. Defect-associated bone marrow edema was found in 78% of the cases. Nevertheless, no correlation between the MOCART score and clinical outcome (IKDC score) could be found (Pearson coefficient, r = 0.173).

CONCLUSION

First-generation ACI leads to satisfying clinical results in terms of patient satisfaction, reduction of pain, and improvement in knee function. Nevertheless, full restoration of knee function cannot be achieved. Although MRI reveals lesions in the majority of the cases and the overall MOCART score seems moderate, this could not be correlated with long-term clinical outcomes.

Preliminary results of a novel single-stage cartilage restoration technique: particulated juvenile articular cartilage allograft for chondral defects of the patella

PURPOSE

To evaluate outcomes and magnetic resonance imaging (MRI) findings after use of particulated juvenile cartilage for the treatment of focal Outerbridge grade 4 articular cartilage defects of the patella.

METHODS

From 2007 to 2011, 16 patients (2 bilateral) underwent a novel single-stage articular cartilage restoration procedure using particulated juvenile articular cartilage allograft. We enrolled 15 knees (13 patients) in this study. The mean age at surgery was 26.4 ± 9.1 years, and the mean postoperative follow-up was 28.8 ± 10.2 months. A musculoskeletal radiologist evaluated each knee with postoperative MRI for the International Cartilage Repair Society cartilage repair assessment score, graft hypertrophy, bony changes around the graft, and percent fill of the defect. All patients also completed the Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee Subjective Knee Evaluation, and Kujala clinical outcome survey (scale, 0 to 100), as well as the Tegner activity scale and visual analog pain scale (scale, 0 to 10).

RESULTS

The mean International Cartilage Repair Society cartilage repair assessment score on MRI was 8.0 ± 2.8, a nearly normal assessment. Of 15 knees, 11 (73%) were found to have normal or nearly normal cartilage repair. Three patients had mild graft hypertrophy whereas 2 had gross graft hypertrophy, 2 of whom required arthroscopic debridement because of symptoms. The mean fill of the defect at follow-up was 89% ± 19.6%, with 12 of 15 knees (80%) showing at least 90% defect coverage. The mean clinical outcome score at follow-up was 73.3 ± 17.6 for the International Knee Documentation Committee evaluation, and the mean scores for each subdomain of the Knee Injury and Osteoarthritis Outcome Score were as follows: 84.2 ± 14.2 for pain, 85.0 ± 12.3 for symptoms and stiffness, 88.9 ± 12.9 for activities of daily living, 62.0 ± 25.1 for sports and recreation, and 60.8 ± 28.6 for quality of life. The median score for the Kujala survey was 79 (range, 55 to 99). The median score on the Tegner activity scale was 5 (range, 3 to 9), and the mean score on the visual analog scale was 1.9 ± 1.4, indicating minimal pain.

CONCLUSIONS

Preliminary results suggest that cartilage restoration using particulated juvenile articular cartilage allograft offers a viable option for patients with focal grade 4 articular cartilage defects of the patella.

Accelerated weightbearing rehabilitation after matrix-induced autologous chondrocyte implantation in the tibiofemoral joint: early clinical and radiological outcomes

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has become an established technique for the repair of full-thickness chondral defects in the knee, although best patient outcomes appear limited by a lack of evidence-based knowledge on how to progressively increase postoperative weightbearing (WB) and rehabilitation exercises.

HYPOTHESIS

To determine the safety and efficacy of an accelerated WB regimen after MACI in the tibiofemoral joint.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Clinical and radiological assessments were performed in 28 knees at 12 months after MACI to the medial or lateral femoral condyle. Both rehabilitation interventions sought to protect the implant for an initial period and then incrementally increase load bearing. Under the "accelerated" (AR) protocol, patients reached full WB at 6 weeks after surgery compared with 8 weeks for what was considered to be the current "best practice" (CR) WB regimen based on previous research. Assessments included the Knee Injury and Osteoarthritis Outcome Score (KOOS), 36-Item Short Form Health Survey (SF-36), visual analog scale, 6-minute walk test, and active knee range of motion (ROM). High-resolution magnetic resonance imaging (MRI) was used to describe the quality and quantity of repair tissue via the assessment of pertinent parameters of graft repair as well as an MRI composite score.

RESULTS

Patients in both groups demonstrated significant improvement (P < .05) in all clinical measures over the preoperative and postoperative timeline from before surgery to 12 months after surgery. The AR group reported significantly better (P < .05) SF-36 physical component scores at 8 weeks and significantly greater (P < .05) KOOS quality of life scores at 6 and 12 months postoperatively. Although no differences (P > .05) were observed between the 2 groups for active knee ROM, the AR group did achieve full active knee extension as early as 4 weeks compared with the CR group at 12 weeks. There was no difference (P > .05) in graft quality as assessed by MRI (MOCART composite score: AR, 3.34; CR, 3.04), with no patients suffering any adverse effects from the implant up to 12 months, regardless of the rehabilitation protocol employed.

CONCLUSION

The AR approach that reduced the length of time spent ambulating on crutches resulted in improved general physical function and quality of life and an earlier attainment of full active knee extension when compared with the CR approach. There were no graft complications ascertained through MRI. This regimen appears safe and may potentially speed up the recovery of normal gait function. A larger patient cohort and follow-up are required to observe long-term graft outcomes.

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

BACKGROUND

While MRI can provide a detailed morphological evaluation after articular cartilage repair, its additional value in determining clinical outcome has yet to be determined.

PURPOSE

To evaluate the correlation between MRI and clinical outcome after cartilage repair and to identify parameters that are most important in determining clinical outcome.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A systematic search was performed in Embase, MEDLINE, and the Cochrane Collaboration. Articles were screened for relevance and appraised for quality. Guidelines in the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) Statement were used. Chi-square tests were performed to find variables that could determine correlation between clinical and radiological parameters.

RESULTS

A total of 32 articles (total number of patients, 1019) were included. A majority (81%) were case series or cohort studies that used similar standardized MRI techniques. The mean Coleman score was 63 (range, 42-96). For the majority of MRI parameters, limited or no correlation was found. Nine studies (28%) found a correlation between clinical outcome and the composite magnetic resonance observation of cartilage repair tissue (MOCART) or Henderson score and 7 (22%) with defect fill. In 5 studies, a weak to moderate correlation was found between clinical outcome and the T2 index (mean Pearson coefficient r = .53).

CONCLUSION

Strong evidence to determine whether morphological MRI is reliable in predicting clinical outcome after cartilage repair is lacking. Future research aiming specifically at clinical sensitivity of advanced morphological and biochemical MRI techniques after articular cartilage repair could be of great importance to the field.

Factors predictive of outcome 5 years after matrix-induced autologous chondrocyte implantation in the tibiofemoral joint

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) has become an established technique for the repair of full-thickness chondral defects in the knee. However, little is known about what variables most contribute to postoperative clinical and graft outcomes as well as overall patient satisfaction with the surgery.

PURPOSE

To estimate the improvement in clinical and radiological outcomes and investigate the independent contribution of pertinent preoperative and postoperative patient, chondral defect, injury/surgery history, and rehabilitation factors to clinical and radiological outcomes, as well as patient satisfaction, 5 years after MACI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study was undertaken in 104 patients of an eligible 115 patients who were recruited with complete clinical and radiological follow-up at 5 years after MACI to the femoral or tibial condyles. After a review of the literature, a range of preoperative and postoperative variables that had demonstrated an association with postoperative clinical and graft outcomes was selected for investigation. These included age, sex, and body mass index; preoperative 36-item Short Form Health Survey (SF-36) mental component score (MCS) and physical component score (PCS); chondral defect size and location; duration of symptoms and prior surgeries; and postoperative time to full weightbearing gait. The sport and recreation (sport/rec) and knee-related quality of life (QOL) subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS) were used as the patient-reported clinical evaluation tools at 5 years, while high-resolution magnetic resonance imaging (MRI) was used to evaluate graft assessment. An MRI composite score was calculated based on the magnetic resonance observation of cartilage repair tissue score. A patient satisfaction questionnaire was completed by all patients at 5 years. Regression analysis was used to investigate the contribution of these pertinent variables to 5-year postoperative clinical, radiological, and patient satisfaction outcomes.

RESULTS

Preoperative MCS and PCS and duration of symptoms contributed significantly to the KOOS sport/rec score at 5 years, while no variables, apart from the baseline KOOS QOL score, contributed significantly to the KOOS QOL score at 5 years. Preoperative MCS, duration of symptoms, and graft size were statistically significant predictors of the MRI score at 5 years after surgery. An 8-week postoperative return to full weightbearing (vs 12 weeks) was the only variable significantly associated with an improved level of patient satisfaction at 5 years.

CONCLUSION

This study outlined factors such as preoperative SF-36 scores, duration of knee symptoms, graft size, and postoperative course of weightbearing rehabilitation as pertinent variables involved in 5-year clinical and radiological outcomes and overall satisfaction. This information may allow orthopaedic surgeons to better screen their patients as good candidates for MACI, while allowing treating therapists to better individualize their preoperative preparatory and postoperative rehabilitation regimens for a best possible outcome.

Clinical and radiological outcomes 5 years after matrix-induced autologous chondrocyte implantation in patients with symptomatic, traumatic chondral defects

BACKGROUND

To date, few studies have been published reporting the 5-year follow-up of clinical and radiological outcomes for chondral defects treated with matrix-induced autologous chondrocyte implantation (MACI).

HYPOTHESIS

A significant improvement in clinical and radiological outcomes after treatment of symptomatic, traumatic chondral defects of the knee with the MACI implant will be maintained up to 5 years after surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A prospective evaluation of the MACI procedure was performed in 21 patients with chondral defects of the knee. After the MACI procedure, patients were clinically assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS), the Tegner-Lysholm score, the International Knee Documentation Committee (IKDC) Subjective Knee Form, and the modified Cincinnati score at years 1, 2, and 5. The quality of repair tissue was assessed by magnetic resonance imaging using the magnetic resonance observation of cartilage repair tissue (MOCART) score at months 3 and 6 and years 1, 2, and 5.

RESULTS

Significant improvements (P < .05) were observed for all 5 KOOS subcategories at year 1 and were maintained through year 5 in 90.5% of patients (19/21). Treatment failure occurred in only 9.5% of patients (2/21). Significant improvements (P < .05) from baseline to year 5 were also observed for the IKDC score (30.1 to 74.3), the modified Cincinnati score (38.1 to 79.6), and the Tegner-Lysholm activity score (1.8 to 4.3). Similarly, the MOCART score significantly improved (P < .001) from baseline to year 5 (52.9 to 75.8). After 5 years, complete filling (83%) and integration (82%) of the graft were seen in the majority of patients. Signs of subchondral bone edema were still present in 47% of patients at 5 years. No product-specific adverse events were reported over the 5-year follow-up period.

CONCLUSION

Patients treated with a MACI implant demonstrated significant clinical improvement and good quality repair tissue 5 years after surgery. The MACI procedure was shown to be a safe and effective treatment for symptomatic, traumatic chondral knee defects in this study.

Knee joint preservation with combined neutralising high tibial osteotomy (HTO) and Matrix-induced Autologous Chondrocyte Implantation (MACI) in younger patients with medial knee osteoarthritis: a case series with prospective clinical and MRI follow-up over 5 years

PURPOSE

There is no ideal treatment for younger patients with medial knee osteoarthritis (OA) and varus malalignment. We have investigated the first case series of combined neutralising high tibial osteotomy (HTO) and Matrix-induced Autologous Chondrocyte Implantation (MACI) with MRI. Treatment goals were clinical improvement and delay of arthroplasty.

METHODS

Between 2002 and 2005 18 patients (Mean age 47 years) underwent surgery. Exclusion criteria were lateral compartment and advanced patellofemoral OA. The Knee Injury and Osteoarthritis Outcome Score (KOOS), six minute walk test (6MWT) and a validated MRI score were outcome measures.

RESULTS

There were significant improvements (p<0.05) in all five KOOS domains. Four were significantly maintained to 5 years. The domain "symptoms" and results in the 6MWT dropped off at 5 years. MRI results were first significantly improved (24/12) but declined at 60 months. Good quality infill was found in 33% patients at the study endpoint (n=5/15). Histological investigation of one knee demonstrated full-thickness hyaline-like cartilage (20/12). After 2 early failures and one graft detachment graft fixation was changed (Smart nails instead of sutures in 14 cases). Graft hypertrophy requiring a chondroplasty occurred once. There were no other major complications. Specific minor complications included patellar tendinitis (n=8).

CONCLUSIONS

This combined procedure provides a safe treatment option for younger patients with medial knee OA and varus alignment with significant clinical improvement at 5 years. However, overall graft survival and cartilage infill were poor. Larger studies are needed to statistically verify predictors for longer term cartilage repair in these patients.

Isokinetic knee extensor strength deficit following matrix-induced autologous chondrocyte implantation

BACKGROUND

Autologous chondrocyte implantation has become an established technique for addressing knee cartilage defects. Despite reported improvement in pain and regeneration of hyaline-like repair tissue, little has been reported on the recovery of knee strength.

METHODS

Knee strength assessment was undertaken in 60 patients at 5 years following autologous chondrocyte implantation. Using an isokinetic dynamometer, and during isokinetic knee extension and flexion angular velocities of 60°, 90° and 120°/s, the peak torque, torque at 45° of knee flexion and hamstrings/quadriceps ratio was obtained, in both the operated and non-operated limbs. Pain at the time of assessment was obtained. Independent sample t-tests were used to assess differences in the operated and non-operated sides.

FINDINGS

There were no significant differences (p>0.05) between the operated and non-operated legs in the peak knee flexor torque or knee flexor torque at a knee flexion angle of 45°, at all angular velocities (60°, 90° and 120°/s). While the peak knee extensor torque was less in the operated leg at all angular velocities, these differences were not significant (p>0.05). However, a significantly reduced (p<0.05) knee extensor torque at a knee flexion angle of 45°, was observed at all speeds.

INTERPRETATION

While patients had recovered their knee flexor strength, they still demonstrated a reduced knee extensor strength profile at 5 years. This demonstrates that the early supervised rehabilitation phase following autologous chondrocyte implantation is not sufficient to restore long-term knee strength, and ongoing patient advice and rehabilitation is required extending beyond this early period. It is unknown how this prolonged reduction in strength may affect long-term graft outcome.

Arthroscopic matrix-induced autologous chondrocyte implantation: 2-year outcomes

PURPOSE

To determine the safety and efficacy of a new arthroscopic technique for matrix-induced autologous chondrocyte implantation (MACI) for articular cartilage defects in the knee.

METHODS

We undertook a prospective evaluation of the first 20 patients treated with the MACI technique (including 14 defects on the femoral condyle and 6 on the tibial plateau), followed up for 24 months after surgery. A 12-week structured rehabilitation program was undertaken by all patients. Patients underwent clinical assessment (Knee Injury and Osteoarthritis Outcome Score, Short Form 36 Health Survey, visual analog pain scale, 6-minute walk test, knee range of motion) before surgery and at 3, 6, 12, and 24 months after surgery and underwent magnetic resonance imaging (MRI) assessment at 3, 12, and 24 months after surgery. MRI evaluation assessed 8 previously defined pertinent parameters of graft repair, as well as a combined MRI composite score.

RESULTS

A significant improvement (P < .05) was shown throughout the postoperative time line for all Knee Injury and Osteoarthritis Outcome Score subscales, the physical component score of the Short Form 36 Health Survey, the frequency and severity of knee pain, and the 6-minute walk test. An improvement in pertinent morphologic parameters of graft repair was observed to 24 months, whereas a good to excellent graft infill score and MRI composite score were observed at 24 months after surgery in 90% and 70% of patients, respectively.

CONCLUSIONS

We report a comprehensive 24-month follow-up in the first 20 patients who underwent the arthroscopic MACI technique. This technique is a safe and efficacious procedure with improved clinical and radiologic outcomes over the 2-year period.

A randomized trial comparing accelerated and traditional approaches to postoperative weightbearing rehabilitation after matrix-induced autologous chondrocyte implantation: findings at 5 years

BACKGROUND

While structured postoperative rehabilitation after matrix-induced autologous chondrocyte implantation (MACI) is considered critical, very little has been made available on how best to progressively increase weightbearing and exercise after surgery.

HYPOTHESIS

A significant improvement will exist in clinical and magnetic resonance imaging (MRI)-based scoring measures to 5 years after surgery. Furthermore, there will be no significant differences in outcomes in MACI patients at 5 years when comparing a traditional and an accelerated postoperative weightbearing regimen. Finally, patient demographics, cartilage defect parameters, and injury/surgery history will be associated with graft outcome.

STUDY DESIGN

Randomized controlled trial; level of evidence, 1.

METHODS

Clinical and radiological outcomes were studied in 70 patients who underwent MACI to the medial or lateral femoral condyle, in conjunction with either an "accelerated" or a "traditional" approach to postoperative weightbearing rehabilitation. Under the accelerated protocol, patients reached full weightbearing at 8 weeks after surgery, compared with 11 weeks for the traditional group. Clinical measures (knee injury and osteoarthritis outcome score [KOOS], short-form health survey [SF-36], visual analog scale [VAS], 6-minute walk test, and knee range of motion) were assessed before surgery and at 3, 6, 12, and 24 months and 5 years after surgery. High-resolution MRI was undertaken at 3, 12, and 24 months and 5 years after surgery and assessed 8 previously defined pertinent parameters of graft repair as well as a combined MRI composite score. The association between clinical and MRI-based outcomes, patient demographics, chondral defect parameters, and injury/surgery history was investigated.

RESULTS

Of the 70 patients recruited, 63 (31 accelerated, 32 traditional) underwent clinical follow-up at 5 years; 58 (29 accelerated, 29 traditional) also underwent radiological assessment. A significant time effect (P < .05) was demonstrated for all clinical and MRI-based scores over the 5-year period. While the VAS demonstrated significantly less frequent pain at 5 years in the accelerated group, there were no other significant differences between the 2 groups. Between 24 months and 5 years, a significant improvement (P < .05) in both groups was observed for the sport and recreation subscale of the KOOS as well as a significant decrease (P < .05) in active knee extension for the traditional group. There were no significant differences (P > .05) in the MRI-based scores between 24 months and 5 years after surgery. Patient age and defect size exhibited significant negative correlations (P < .05) with several MRI-based outcomes at 5 years, while there were no significant correlations (P > .05) between clinical and MRI-based outcomes. At 5 years after surgery, 94% and 95% were satisfied with the ability of MACI to relieve their knee pain and improve their ability to undertake daily activities, respectively.

CONCLUSION

The outcomes of this randomized trial demonstrate a safe and effective accelerated rehabilitation protocol as well as a regimen that provides comparable, if not superior, clinical outcomes to patients throughout the postoperative timeline.

Advanced Therapy Medicinal Products and Exemptions to the Regulation 1394/2007: How Confident Can We be? An Exploratory Analysis

The market authorization procedure for medicinal products for human use is relying on their demonstrated efficacy, safety, and pharmaceutical quality. This applies to all medicinal products whether of chemical or biological origin. Since October 2009, the first advanced therapy medicinal product (ATMP) has been authorized through the centralized procedure. ATMPs are gene therapy medicinal products, somatic cell therapy medicinal products or tissue-engineered products. An appropriate ATMP – Regulation is dealing with ATMP requirements. Two exemptions are foreseen to the ATMP Regulation: (a) Products, which were legally on the Community market when the Regulation became applicable, should comply to the Regulation by December 30, 2012. (b) The hospital exemption rule for non-routine products for an individual patient. In this work we explored whether the actual application of the Regulation on ATMPs is in line with the aim of the Regulation in terms of guaranteeing the highest level of health protection for patients. Based on the analysis of the relative efficacy of the only EC authorized ATMP and its exempted alternatives, there is evidence against this Regulation 1394/2007 assumption.

Repair of osteochondral lesions in the knee by chondrocyte implantation using the MACI® technique

PURPOSE

Matrix-associated autologous chondrocyte implantation (MACI(®)) is an innovative therapeutic option for the treatment of chondral and osteochondral lesions of the knee.

METHODS

Fifty-three patients (54 knees) with MRI-documented osteochondral lesions were treated with MACI(®). A clinical assessment was performed using VAS score, Lysholm score, and Tegner activity level after an average follow-up of 27 months (SD: 2.3). MRI scans were performed 12 and 24 months after surgery. Seventeen patients were reevaluated after an average time of 59 months (SD: 6.7) after surgery.

RESULTS

Two years after transplantation, Lysholm score increased from a preoperative mean value of 70 (SD: 13.4) to 95 (SD: 6.4); the average VAS score decreased from a preoperative value of 5.2 (SD: 2.9) to 1.9 (SD: 2.1). The difference with respect to Tegner activity level did not prove to be significant. At 1 year, MRI scans documented a completely repaired defect with slight subchondral bone abnormality in 38 cases (70%). Satisfying outcomes were confirmed on 17 patients who were reevaluated 5 years after surgery. At 60 months, MRI scans showed complete integration with the surrounding native cartilage without any sign of detachment or bone marrow edema in 15 cases (88%).

CONCLUSION

The MACI(®) technique is a safe and clinically effective procedure, which has been proven to be valuable in treating osteochondral defects even over the long term.

LEVEL OF EVIDENCE

Therapeutic study, Level III-2 (retrospective cohort study).

Clinical and magnetic resonance imaging-based outcomes to 5 years after matrix-induced autologous chondrocyte implantation to address articular cartilage defects in the knee

BACKGROUND

The availability remains limited of midterm clinical and radiologic results into matrix-induced autologous chondrocyte implantation (MACI). Outcomes are required to validate the efficacy of MACI as a suitable surgical treatment option for articular cartilage defects in the knee.

HYPOTHESIS

A significant improvement in clinical and magnetic resonance imaging-based (MRI-based) outcomes after MACI will exist throughout the postoperative timeline to 5 years after surgery. Furthermore, patient demographics, cartilage defect parameters, and injury/surgery history will be associated with patient and graft outcome, whereas a significant correlation will exist between clinical and MRI-based outcomes at 5 years after surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A prospective evaluation was undertaken to assess clinical and MRI-based outcomes to 5 years in 41 patients (53 grafts) after MACI to the knee. After MACI surgery and a 12-week structured rehabilitation program, patients underwent clinical assessments (Knee injury and Osteoarthritis Outcome Score, SF-36, 6-minute walk test, knee range of motion) and MRI assessments at 3, 12, and 24 months, as well as 5 years after surgery. The MRI evaluation assessed 8 previously defined pertinent parameters of graft repair, as well as a combined MRI composite score.

RESULTS

A significant improvement (P < .05) was demonstrated for all Knee injury and Osteoarthritis Outcome Score and SF-36 subscales over the postoperative timeline, as well as the 6-minute walk test and active knee extension. A significant improvement (P < .0001) was observed for the MRI composite score, as well as several individual graft scoring parameters. At 5 years after surgery, 67% of MACI grafts demonstrated complete infill, whereas 89% demonstrated good to excellent filling of the chondral defect. Patient demographics, cartilage defect parameters, and injury/surgery history demonstrated no significant pertinent correlations with clinical or MRI-based outcomes at 5 years, and no significant correlations existed between clinical and MRI-based outcome measures. At 5 years after surgery, 98% of patients were satisfied with the ability of MACI surgery to relieve knee pain; 86%, with improvement in their ability to perform normal daily tasks; and 73%, with their ability to participate in sport 5 years after MACI.

CONCLUSION

These results suggest that MACI provides a suitable midterm treatment option for articular cartilage defects in the knee. Long-term follow-up is essential to confirm whether the repair tissue has the durability required to maintain long-term patient quality of life.