Return to Sports Activity and Work After Autologous Chondrocyte Implantation of the Knee: Which Factors Influence Outcomes?

Background: Autologous chondrocyte implantation (ACI) has been associated with satisfying results in everyday activities. Clinical results after ACI treatment of femorotibial lesions are superior in comparison with patellofemoral lesions. There is limited information regarding at which level recreational, amateur, and professional athletes can resume sports and physical activities as well as work after ACI and what parameters influence return to work and sports. Hypothesis: Return to sports activity and work is dependent on defect characteristics such as location and size. Study Design: Case series; Level of evidence, 4. Methods: A total of 130 patients with isolated full-thickness cartilage defects of the knee joint treated with ACI between June 2000 and October 2007 were retrospectively studied by an established questionnaire that assessed sports-specific questions such as frequency, duration, and intensity. Engagement in 32 different sports disciplines was evaluated. In addition, work-specific data were evaluated according to classifications established by the REFA Association. Results were evaluated depending on patient- and defect-specific parameters. Results: The mean SD patient age at ACI was 36.2 +/- 9.2 years, with a mean defect size of 4.4 +/- 1.7 cm(2). Defects were located at the femorotibial compartment in 55.7% of cases, whereas lesions of the patellofemoral compartment were found in 44.3%. Mean duration of inability to work after ACI was 13.6 +/- 11.0 weeks and did not appear to be influenced by patient age. Defect location and defect size did not appear to significantly influence return-to-work rates, but work intensity before surgery significantly influenced return-to-work rates and duration of absence from work. Workplace adaptations were necessary in only 9.2% of cases postoperatively. With regard to postoperative sports activity, 73.1% of patients were able to return to sports. Neither defect location nor size significantly influenced return to physical activity. Patients participated in a mean of 2.3 different sports during their lifetime. Both duration of exercise and number of sessions per week significantly decreased from before to after surgery. Detailed analysis of 32 different sporting activities revealed that high-impact as well as start-stop sports were generally abandoned in favor of endurance and low-intensity exercises. A lifetime level of competitiveness was maintained in 31.3% of cases, while return to elite sports at the time of the survey became highly unlikely (0.8%). Conclusion: 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.