Aim

It has been suggested that the use of a pilot-hole may reduce the risk of fracture to the lateral cortex. Therefore the purpose of this study was to determine the effect of a pilot hole on the strains and occurrence of fractures at the lateral cortex during the opening of a high tibial osteotomy (HTO) and post-surgery loading.

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.

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.

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.