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.

The study results illustrate that treatment of articular cartilage defects of the knee joint leads to satisfactory results concerning everyday activities. With the exception of physical labor, no essential adaptations needed to be made at work. Regarding sports activity, return to low- and moderate-intensity levels appears realistic in the majority of cases, whereas the likelihood of returning to activities with high stress applied on the knee joint is low. Neither defect location nor size appears to significantly influence postoperative sports activity or return-to-work rates.

The MRI outcome is imperfect in this collective of patients. There is only weak correlation of quantitative imaging data and clinical function. Qualitative imaging data are much better correlated to functional outcomes.

The use of a collagen membrane in combination with autologous chondrocytes (second generation ACI) leads to superior clinical long-term outcome compared to first generation ACI. Based on these results, second generation ACI should be preferred over first generation ACI.

Objective:Although autologous chondrocyte implantation (ACI) has become an established surgical treatment for cartilage defects of the knee, little is known about what patients expect about this surgery.Design:A total of 150 patients who underwent ACI for cartilage defects at the knee were assigned to the present study and asked about their expectations and estimation concerning the ACI procedure. Patients were asked to answer 4 questions of a web-based questionnaire concerning their expectations on clinical outcome and on factors they considered relevant for clinical outcome.Results:A total of 118 (79%) returned questionnaires. Mean patient age was 32.6 years and mean defects size was 4.1 cm2. A proportion of 70% (n = 83) of patients expected pain-free sports participation as a result of the ACI surgery, including 24 patients who expected to return to high-impact sports without any restrictions. Only 12.7% expected a reduction but persistence of pain during everyday activities. Concerning factors that influence outcome, the majority of the patients (55.1%) considered defect characteristics (i.e., size and location) most important for clinical outcome, whereas only a small proportion of patients considered rehabilitation (7.6%), cell quality (10.2%), or prior surgeries (4.2%) more relevant for final outcome.Conclusion:The present study illustrates that expectations of ACI patients are demanding and quite high. The ACI technique seems generally considered to be able to restore pain-free sports participation. Patients do not seem to be aware of all factors of possible importance concerning clinical outcome.