Patient-Reported and Magnetic Resonance Imaging Outcomes of Third-Generation Autologous Chondrocyte Implantation After 10 Years

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

IV-case series.

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.

Minimum 10-Year Outcomes of Matrix-Induced Autologous Chondrocyte Implantation in the Knee: A Systematic Review

BACKGROUND

Matrix-induced autologous chondrocyte implantation (MACI) is an established cell-based therapy for the treatment of chondral defects of the knee. As long-term outcomes are now being reported in the literature, it is important to systematically review available evidence to better inform clinical practice.

PURPOSE

To report (1) subjective patient-reported outcomes (PROs) and (2) the rate of graft failure, reoperation, and progression to total knee arthroplasty (TKA) after undergoing MACI of the knee at a minimum 10-year follow-up.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive search of Ovid MEDLINE and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily; Ovid Embase; Ovid Cochrane Central Register of Controlled Trials; Ovid Cochrane Database of Systematic Reviews; and Scopus from 2008 to September 15, 2022, was conducted in the English language. Study eligibility criteria included (1) full-text articles in the English language, (2) patients undergoing a MACI within the knee, (3) clinical outcomes reported, and (4) a minimum 10-year follow-up.

RESULTS

In total, 168 patients (99 male, 69 female; mean age, 37 years [range, 15-63 years]; mean body mass index, 26.2 [range, 18.6-39.4]) representing 188 treated chondral defects at a minimum 10-year follow-up after MACI were included in this review. Significant and durable long-term improvements were observed across multiple PRO measures. Follow-up magnetic resonance imaging (MRI), when performed, also demonstrated satisfactory defect fill and an intact graft in the majority of patients. The all-cause reoperation rate was 9.0%, with an overall 7.4% rate of progression to TKA at 10 to 17 years of follow-up.

CONCLUSION

At a minimum 10-year follow-up, patients undergoing MACI for knee chondral defects demonstrated significant and durable improvements in PROs, satisfactory defect fill on MRI-based assessment, and low rates of reoperation and TKA. These data support the use of MACI as a long-term treatment of focal cartilage defects of the knee.

Positive outcomes following Autologous Matrix-Induced Chondrogenesis (AMIC) in the treatment of retropatellar chondral lesions: a retrospective analysis of a patient registry

BACKGROUND

The patellofemoral joint is a challenging environment for treating chondral defects. Among the surgical options for the treatment of chondral defects, the single-stage Autologous Matrix-Induced Chondrogenesis (AMIC) procedure uses a porcine collagen I/III membrane to enhance bone-marrow stimulation. However, longer term outcomes data are rare for this specific indication. In order to provide real-world information, an ongoing registry has been established to record patient data and outcomes when AMIC is used to treat chondral and osteochondral lesions.

METHODS

Patient data were retrieved from an ongoing, prospective, multisite registry of patients who had undergone AMIC treatment of chondral defects. We identified 64 patients who had undergone AMIC for patellofemoral chondral defects and for whom pre-operative and at least 1 post-operative score were available were included in this retrospective data analysis. Outcomes were assessed via the KOOS, VAS pain, and the Lysholm scores. Outcomes at the post-operative time-points were analysed using a factorial ANOVA with post-hoc testing while linear regression was used to assess associations between the change in the Lysholm score and lesion size.

RESULTS

There was a significant improvement in Lysholm, VAS pain, and KOOS scores from pre-operative to the 1st year post-operative (p < 0.001), and this was maintained during the follow-up.

CONCLUSIONS

The forces exerted on the patellofemoral joint make this a challenging scenario for chondral repair. Our data demonstrates that the AMIC procedure with a collagen I/III membrane is an effective treatment for retropatellar cartilage lesions, and provides reliable results, with decreased pain and improved function. Importantly, these improvements were maintained through the follow-up period.

Dynamic Postural Stability after Cartilage Repair in the Knee

Background:

Articular cartilage has an exceptionally poor capacity for healing, but Autologous Matrix Induced Chondrogenesis is a procedure with a substantial body of literature that demonstrates its performance in chondral and osteochondral repair. However, data concerning dynamic postural stability after cartilage repair procedures is lacking.

Objective:

Therefore, the present study was designed to assess postural stability following cartilage repair in the knee.

Methods:

20 adults had undergone Autologous Matrix Induced Chondrogenesis for the treatment of full-thickness cartilage defects, with minimum 36 months of follow-up. Clinical outcomes were evaluated by patient reported outcome measures while dynamic postural stability was assessed using the star excursion balance test. The untreated, contralateral limbs served as controls.

Results:

At a mean follow-up of 43 months, patients reported a Visual Analog Score for pain of 1.6±2.2, a mean Lysholm score of 78.5±17.9 and a mean Knee Osteoarthritis Outcome Score of 143.3±16.1. The star excursion balance test showed no significant difference between limbs.

Conclusion:

With no difference in dynamic postural stability, our results indicate that this treatment provides a positive clinical outcome, with no deficits in postural stability when compared to the contralateral, untreated leg.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Autologous chondrocyte implantation combined with anterior cruciate ligament reconstruction: similar short-term results in comparison with isolated cartilage repair in ligament intact joints

PURPOSE

Both acute ruptures of the anterior cruciate ligament (ACL) as well as chronic ACL insufficiency show a high association with focal cartilage defects of the knee. However, the results after combined ACL reconstruction and cartilage repair are not well investigated. The aim of the present study was to investigate the short-term outcomes after autologous chondrocyte implantation (ACI) in combination with ACL reconstruction and to compare the results with patients who underwent isolated ACI in ligament intact knees.

METHODS

All patients who were registered in the German Cartilage Registry with ACI for focal cartilage defects in the knee joint in combination with ACL reconstruction and who completed the 24 month follow-up were included in the study group. A matched-pair procedure according to gender, defect location, defect size, and age was used to create a control group of patients with isolated ACI in ACL intact joints. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the numeric analog scale for pain (NAS) were used to assess the preoperative state as well as the clinical outcomes 12 and 24 months after surgery.

RESULTS

A total of 34 patients were included in both the study group (age mean 33.3 ± SD 8.8 years) and the control group (33.6 ± 8.4 years) with a median defect size of 466 (25%-75% IQR 375-600) mm² and 425 (IQR 375-600) mm², respectively. In comparison with the preoperative state (median 67, IQR 52-75), the study group showed a significant increase of the total KOOS after 12 months (78, IQR 70-86; p = 0.014) and after 24 months (81, IQR 70-84; p = 0.001). The NAS for pain did not change significantly in the postoperative course. In comparison with the control group there was no significant difference for the total KOOS neither preoperative (control group median 67, IQR 52-73) nor at any postoperative time point (12 months: 82, IQR 67-93; 24 months: 81, IQR 71-91).

CONCLUSION

The clinical short-term outcomes after ACI at the knee joint in combination with ACL reconstruction are good and similar to the results after isolated ACI in ligament intact knees.

LEVEL OF EVIDENCE

III.

Hydrogel-based autologous chondrocyte implantation leads to subjective improvement levels comparable to scaffold based autologous chondrocyte implantation

PURPOSE

Scaffold-based autologous chondrocyte implantation is a well-established treatment for cartilage defects in the knee joint. Hydrogel-based autologous chondrocyte implantation using an in situ polymerizable biomaterial is a relatively new treatment option for arthroscopic cartilage defects. It is therefore important to determine if there are significant differences in the outcomes. The aim of this study is to compare the outcomes (using subjective parameters) of hydrogel-based autologous chondrocyte implantation (NOVOCART^® Inject) with the outcomes of scaffold based autologous chondrocyte Implantation (NOVOCART^® 3D) using biphasic collagen scaffold.

METHODS

The data of 50 patients, which were paired with 25 patients in each treatment group, was analyzed. The main parameters used for matching were gender, number of defects and localization. Both groups were compared based on Visual Analogue Scale (VAS) and subjective IKDC scores, both of which were examined pre-operatively and after 6, 12 and 24 months.

RESULTS

Significant benefits in both VAS and IKDC scores after 2 years of follow-up in both groups were found. Comparing the groups, the results showed that in the hydrogel-based autologous chondrocyte implantation group, significant changes in IKDC scores are measurable after 6 months, while it takes 12 months until they are seen in the scaffold based autologous chondrocyte group.

CONCLUSION

Hydrogel-based autologous chondrocyte and scaffold based autologous chondrocyte show comparable improvements and significant benefits to the patients' subjective well-being after a 2-year-follow-up.

LEVEL OF EVIDENCE

III.

Minced Cartilage Procedure for One-Stage Arthroscopic Repair of Chondral Defects at the Glenohumeral Joint

Chondral defects of the glenohumeral joint are common but still remain a diagnostic and management challenge. Whereas arthroplasty is a reasonable treatment option in the elderly and low-demand population, joint preservation should be aimed for the remaining patients. For larger defects the current gold standard of treatment is autologous chondrocyte implantation. However, disadvantages such as high cost, the restriction in availability of specialized laboratories, and the 2-stage surgical design need to be accounted for if choosing this option. Showing first good clinical results for the knee joint, minced cartilage implantation is moreover a cost-effective procedure bringing autologous cartilage chips harvested from the defect walls and bringing them into the area of damage in a single-step open or arthroscopic approach. We describe an arthroscopic strategy of this technique to treat chondral defects at the glenohumeral joint.

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.

Third-Generation Autologous Chondrocyte Implantation at the Knee Joint Using the Igor Scaffold: A Case Series With 2-Year Follow-up

Background:

For large, locally restricted cartilage defects in young patients, third-generation matrix-supported autologous chondrocyte implantation (ACI) with a variety of scaffolds has shown good mid- to long-term results.

Purpose/Hypothesis:

This study aimed to monitor the clinical and radiological outcomes of patients who received ACI at the knee joint using the Igor scaffold (IGOR–Institute for Tissue and Organ Reconstruction) at 2-year follow-up. Our hypothesis was that there would be improvements in postoperative subjective scores and cartilage repair tissue quality.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 21 patients (12 male and 9 female) were available for 2-year follow-up after third-generation ACI using the Igor scaffold. All were clinically assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Scale, Brittberg score, International Knee Documentation Committee (IKDC) Subjective Knee Form, Noyes Sports Activity Rating Scale, and visual analog scale for pain. For morphological evaluation, the magnetic resonance observation of cartilage repair tissue (MOCART) and MOCART 2.0 scores were calculated using 3-T magnetic resonance imaging performed at 3, 6, 12, and 24 months postoperatively. Results were compared between baseline and 24 months postoperatively.

Results:

After 2 years, the clinical and radiological scores showed good to excellent results in the majority of patients. On the IKDC, 10 patients were graded as excellent, 4 as good, 5 as fair, and 2 as severe; on the KOOS, 7 patients were graded as excellent, 8 as good, 4 as fair, and 2 as severe. From baseline to latest follow-up, visual analog scale pain scores decreased from 5.6 ± 3.2 (mean ± SD) to 1.5 ± 2; KOOS results increased from 51 ± 20.7 to 75.2 ± 15.4; and the Tegner score improved from 2.2 ± 1.8 to 4.3 ± 1.3. The MOCART and MOCART 2.0 scores were comparable at 2-year follow-up, with mean values of 74 ± 10 and 78 ± 13, respectively. Satisfactory filling and integration were found in 90.5%. Overall, 16 of 21 patients (76.1%) were satisfied with the surgery and would undergo the procedure again.

Conclusion:

Third-generation ACI using the Igor scaffold showed improvements in clinical and radiological results that were comparable with other scaffolds for patients with large traumatic or degenerative cartilage defects. Patients reported a decrease in pain and an increase in activity, with the majority reporting good results.

Third generation autologous chondrocyte implantation is a good treatment option for athletic persons

PURPOSE

Autologous chondrocyte implantation is an established method for the treatment of joint cartilage damage. However, to date it has not been established that autologous chondrocyte implantation is an appropriate procedure for cartilage defects therapy in athletic persons. The aim of this study is to analyze if third-generation autologous chondrocyte implantation is an appropriate treatment for athletic persons with full cartilage defect of the knee joints.

METHODS

A total of 84 patients were treated with third-generation autologous chondrocyte implantation (NOVOCART^® 3D). The mean follow-up time was 8 years (5-14). Sports activity was measured via UCLA Activity Score and Tegner Activity Scale before the onset of knee pain and postoperatively in an annual clinical evaluation. 41 athletic persons and 43 non-athletic persons (UCLA-Cut-off: 7; Tegner Activity Scale-Cut-off: 4) were analyzed. Patient reported outcomes were captured using IKDC subjective, KOOS, Lysholm score and VAS score on movement.

RESULTS

Patient reported outcomes (IKDC, VAS at rest, VAS on movement) showed significant improvement (p < 0.001) postoperatively. Athletic persons demonstrated significantly better results than non-athletic persons in the analyzed outcome scores (IKDC: p < 0.01, KOOS: p < 0.01, Lysholm score: p < 0.01). 96.4% of the patients were able to return to sport and over 50% returned or surpassed their preinjury sports level. The remaining patients were downgraded by a median of two points on the UCLA- and 2.5 on the Tegner Activity Scale. A shift from high-impact sports to active events and moderate or mild activities was found. Furthermore, it was shown that preoperative UCLA score and Tegner Activity Scale correlated significantly with the patient reported outcome postoperatively.

CONCLUSION

Autologous chondrocyte implantation is a suitable treatment option for athletic persons with full-thickness cartilage defects in the knee. The return to sports activity is possible, but includes a shift from high-impact sports to less strenuous activities.

Third generation autologous chondrocyte implantation is a good treatment option for athletic persons

PURPOSE

Autologous chondrocyte implantation is an established method for the treatment of joint cartilage damage. However, to date it has not been established that autologous chondrocyte implantation is an appropriate procedure for cartilage defects therapy in athletic persons. The aim of this study is to analyze if third-generation autologous chondrocyte implantation is an appropriate treatment for athletic persons with full cartilage defect of the knee joints.

METHODS

A total of 84 patients were treated with third-generation autologous chondrocyte implantation (NOVOCART^® 3D). The mean follow-up time was 8 years (5-14). Sports activity was measured via UCLA Activity Score and Tegner Activity Scale before the onset of knee pain and postoperatively in an annual clinical evaluation. 41 athletic persons and 43 non-athletic persons (UCLA-Cut-off: 7; Tegner Activity Scale-Cut-off: 4) were analyzed. Patient reported outcomes were captured using IKDC subjective, KOOS, Lysholm score and VAS score on movement.

RESULTS

Patient reported outcomes (IKDC, VAS at rest, VAS on movement) showed significant improvement (p < 0.001) postoperatively. Athletic persons demonstrated significantly better results than non-athletic persons in the analyzed outcome scores (IKDC: p < 0.01, KOOS: p < 0.01, Lysholm score: p < 0.01). 96.4% of the patients were able to return to sport and over 50% returned or surpassed their preinjury sports level. The remaining patients were downgraded by a median of two points on the UCLA- and 2.5 on the Tegner Activity Scale. A shift from high-impact sports to active events and moderate or mild activities was found. Furthermore, it was shown that preoperative UCLA score and Tegner Activity Scale correlated significantly with the patient reported outcome postoperatively.

CONCLUSION

Autologous chondrocyte implantation is a suitable treatment option for athletic persons with full-thickness cartilage defects in the knee. The return to sports activity is possible, but includes a shift from high-impact sports to less strenuous activities.

Editorial Commentary: Third-Generation Autologous Chondrocyte Implantation-Are Cells Seeded Onto the Scaffold Itself in It for the Long Run?

Autologous chondrocyte implantation (ACI) is an increasingly performed procedure, with rapidly evolving technology. First-generation ACI used a periosteal patch, leading to the second generation, in which a type I-type III collagen membrane is used to cover the autologous chondrocytes, and ultimately the third generation, in which autologous chondrocytes are seeded onto the scaffold itself. As third-generation, scaffold-based ACI techniques are becoming more widely available, interest in the long-term clinical and radiographic outcomes continues to grow, especially given the high costs associated with these procedures. Several studies have now shown persistently improved clinical outcomes at long-term follow-up, which support the increasing utilization of third-generation ACI techniques. However, it is important to continue to develop our understanding of the limitations of and expectations with third-generation ACI, particularly regarding reoperation, as well as to continue to design high-quality long-term studies that can evaluate differences in technology.