Focal chondral defects are thought to contribute to the onset of degenerative changes in cartilage and therefore effective treatments of these lesions are aggressively pursued. A number of options such as bone marrow stimulation, osteochondral autograft transplantation, osteochondral allograft transplantation, and autologous chondrocyte implantation exist. Long-term data regarding efficacy and outcome for some of these approaches seem to suggest that there is still a need for a low-cost, effective treatment that leads to a sustained improvement in symptoms and the formation of hyaline cartilage.

artilage autologous implantation system (CAIS) is a surgical method in which hyaline cartilage fragments from a non-weight bearing area in the knee joint are collected and then precipitated onto an absorbable filter that is subsequently placed in the focal chondral defect. The clinical outcome of CAIS was compared with microfracture (MFX) in a pilot study. In an IRB approved protocol patients (n=29) were screened with the intention to treat, randomised (2:1, CAIS:MFX) and followed over a 24 month period. To be included in the study the patient may have up to 2 contained focal, unipolar lesions (≤ ICRS grade 3d and ≤ ICRS Grade IVa OCD lesions of femoral condyles and trochlea with a size between 1 and 10 cm². There were no differences in the demographics between the two treatment groups. We report 24 month patient-reported outcome (PRO) data using the KOOS-scale. The values (mean±SD) for the Sport&Recreation (S&R) and Quality of Life scales are shown in the figures below. We noted that at 12 months after the intervention CAIS differentiated itself from MFX in that the changes in S&R were different (p<0.05, t-test) at 12, 18, and 24 months. QoL data were different at 18 and 24 months. The other KOOS-subscales in CAIS and MFX were not significantly different at any time point. The data suggest that CAIS led to an improvement in clinical outcomes in the second year post-intervention. It is possible that the improvement of symptoms that we measured may be associated with the formation of hyaline cartilage. Study funded by ATRM and DePuyMITEK.

We assessed 224 patients treated with Autologous Chondrocyte Implantation performed 10–20 years ago (average 12.8 years). Average age at the time of the implantation was 33.3 years. Average size of lesion was 5.3 cm2 (range 0.6–16), while 55 patients sustained multiple lesions. The participants filled out five questionnaires. Lysholm score, Tegner-Walgren, modified Cincinnati (Noyes), Brittberg score, and KOOS were assessed. In addition, the patients were asked to grade their current situation compared to their previous follow up as better, worse of unchanged. Finally, they were asked if they would do the operation again, answering with yes or no.

The patients were divided into groups according to the location and characteristics of the cartilage lesions, or concomitant surgeries during the ACI. Assessment of the outcomes reveals a significant improvement in all groups, compared with the preoperative values.

There is no other study assessing a cartilage treatment with such a long follow up. According to the results of that study, autologous chondrocyte implantation seems to be an effective and durable solution for the treatment of large full thickness cartilage and osteochondral lesions of the knee joint

The Cartilage Autograft Implantation System (CAIS) is being investigated as a potential alternative surgical treatment to provide chondrocyte-based repair in a single procedure for articular cartilage lesion(s) of the knee. CAIS involves preparation and delivery of mechanically morselized, autologous cartilage fragments uniformly dispersed on a 3-dimensional, bio-absorbable scaffold and fixated in the lesion with bio-absorbable staples. CAIS maintains chondrocyte viability and creates increased surface area, which facilitates the outgrowth of embedded chondrocytes onto the scaffold. A proprietary disposable arthroscopic device for harvesting precisely morselized cartilage tissue is used.

In an EU pilot clinical study involving 5 countries 25 patients were randomized and treated using a 2:1 schema of CAIS:microfracture (MFX). Subjects returned for follow-up visits at 1 and 3 weeks and then 2, 3, 6, 9, 12, 18 and 24 months and were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Outcomes at each time point were analyzed with Students t-test.

This study showed that CAIS is safe to use. During the first year, the clinical outcome data in both groups were similar. However, at 18 and 24 months we noted that selected outcome measures were different. At 18 months the Sports & Recreation values were 50.6 ± 22.70 and 21.3 ± 33.25 (p=0.016) for CAIS and MFX respectively and at 24 months 52.1 ± 27.9 and 26.7 ± 26.2 (p=0.061) for CAIS and MFX respectively. At these same time points the Quality of Life data were 43.0 ± 27.14 and 27.2 ± 29.11 (p=0.2) for CAIS and MFX respectively (18 months) and 45.1 ± 28.07 and 20.5 ± 21.47 (p=0.062) for CAIS and MFX respectively (24 months).

While some of the data are not significantly different in this pilot study, taken together they do provide evidence to support the initiation of a more robust clinical trial to investigate efficacy.

Since 1987, autologous chondrocyte implantation (ACI) has been performed in Gothenburg, Sweden in more than 1600 patients. Out of the first 442 patients operated with ACI, 153 (35%) had patella lesions and 91 (21%) had trochlea lesions. Forty two patients (9.5%) had kissing lesions of the patellofemoral joint.

The aim of the study was to evaluate the current clinical status of operated patients. Lysholm and Tegner-Wallgren self-assessment questionnaires were used. The patients were requested to compare their current status to previous states and to report whether they would do the operation again. Concomitant realignment procedures of the patellofemoral joint were also recorded and preoperative scores were also assessed from the medical files.

Patients were divided into groups according to the location of lesion. All the groups showed a significant improvement compared with the preoperative assessment. Over 90% of the treated patients were satisfied with the ACI and would have undergone the procedure again.

It seems that correcting the coexisting background factors with realignment, stabilizing or unloading procedures is improving the results over time. Despite the initial controversy about the results and indication for ACI in patellofemoral lesions, it is clear that ACI provides a satisfactory result even for the difficult cases with concomitant patellar instability. Our study reveals preservation of the good results and of high level of patients’ activities, even 10 to 20 years after the implantation.

The Cartilage Autograft Implantation System (CAIS) is being developed as a potential alternative surgical treatment providing chondrocyte-based repair in a single procedure for articular cartilage lesion(s) of the knee. Two pilot clinical studies were conducted to assess safety and initial performance of the CAIS system.

CAIS involves preparation and delivery of mechanically morselized, autologous cartilage uniformly dispersed on a 3-dimensional, bio-absorbable scaffold, and fixated in the defect with bio-absorbable staples. The mechanical fragmentation of cartilage tissue both maintains viability of the chondrocytes and creates increased surface area, which facilitates the outgrowth of embedded chondrocytes onto the scaffold. A proprietary disposable, arthroscopic device for precisely harvesting viable, morselized cartilage tissue was used. Two pilot clinical studies conducted in the EU and US were designed to assess safety and initial performance of the CAIS. The studies treated 53 patients at 10 enrolling sites, with microfracture as a control. Subjects returned for follow-up visits up to 3 years. Subjects were clinically evaluated and interviewed for the occurrence of adverse events and asked to complete clinical outcome questionnaires, Knee Injury and Osteoarthritis Outcome Score (KOOS), regarding disability, function, pain and quality of life. In addition, MRIs were completed at baseline, 3 weeks, and 6, 12, 24, and 36 months.

The instrumentation enabled the successful preparation and fixation of morselized autologous cartilage tissue loaded implant in a single intraoperative setting. The CAIS device has demonstrated short-term safety in subjects treated to date. Preliminary data from the US pilot study at 12 months and EU pilot study at 6 months indicate that CAIS is safe and its performance based on KOOS clinical outcomes show improvement over baseline and comparability to microfracture. Additional data must be analyzed regarding long-term safety and performance.