Revision Surgery After Cartilage Repair: Data From the German Cartilage Registry (KnorpelRegister DGOU).

Background: Various operative strategies have been introduced to restore the integrity of articular cartilage when injured. The frequency of revision surgery after cartilage regenerative surgery remains incompletely understood.

Purpose/Hypothesis: The purpose of this study was to identify the reasons for revision surgery after cartilage regenerative surgery of the knee. We hypothesized that in a large patient cohort, revision rates would differ from those in the current literature.

Study Design: Case-control study; Level of evidence, 3.

Methods: A total of 2659 complete data sets from the German Cartilage Registry were available for analyses. In brief, baseline data were provided by the attending physician at the time of index surgery. Follow-up data were collected using a web-based questionnaire inquiring whether patients had needed revision surgery during follow-up, which was defined as the endpoint of the present analysis.

Results: A total of 88 patients (3.3%) reported the need for revision surgery as early as 12 months postoperatively. Among the most common causes were arthrofibrosis (n = 27) and infection (n = 10). Female patients showed a significantly greater complication rate (4.5%) when compared with male patients (2.6%; P = .0071). The majority of cartilage lesions were located at the medial femoral condyle (40.2%), with a mean defect size of 3.5 ± 2.1 cm2 . Neither the location nor defect size appeared to lead to an increased revision rate, which was greatest after osteochondral autografts (5.2%) and autologous chondrocyte implantation (4.6%). Revision rates did not differ significantly among surgical techniques. Chi-square analysis revealed significant correlations between the number of previous joint surgeries and the need for revision surgery ( P = .0203). Multivariate regression analysis further confirmed sex and the number of previous surgeries as variables predicting the need for early revision surgery.

Conclusion: The low early revision rates found in this study underline that today's cartilage repair surgeries are mostly safe. Although invasiveness and techniques differ greatly among the procedures, no differences in revision rates were observed. Specific factors such as sex and the number of previous surgeries seem to influence overall revision rates and were identified as relevant risk factors with regard to patient safety.