Summary

MRI and CT evaluation of the bony integration and cartilage morphology of TruFit Plugs placed to fill chondral defects in the knee.

Abstract

Objective

To evaluate the bony integration and cartilage morphology of TruFit Plugs (Smith & Nephew) placed to fill chondral defects in the knee.

Methods

17 patients underwent osteobiologic plug implantation for chondral defects of the knee. 13 plugs in 7 patients (mean age 38 years, range 21-49) were available for radiographic review. The mean follow up was 36.4 months (range 20-57 months). Each patient underwent CT for evaluation of bony integration as judged by a percentage of integration. The Hounsfield units (HU) of the plug and the native bone were recorded. A percentage of HU implant and HU native cancellous bone (HU implant/HU native bone) was calculated. MRI was used to evaluate the amount and quality of articular cartilage.

Results

CT results showed percentage of bony integration to be mean 37.7% (range 0-100, SD ±30.1). HU implant/HU native bone was mean 32.2%, range 11.8-64.9. MRI showed articular cartilage fill to be: 38.5% filled 0-25% of the defect, 15.3% filled 25-50%, 23.1% filled 50-75%, and 23.1% filled 75-100%. T2 fat saturated signals were isointense in 26.9%, hyperintense in 34.6%, intermediate in 23.1%, hypointense in 23.1%, and cancellous bone in 7.7%.

Conclusion

In this study bony integration of the TruFit Plug was poor. Amount of articular cartilage fill was significantly incomplete. The quality of resulting cartilage was inconsistent.