Biomechanical Evaluation of a Novel Suture Augment in Patella Fixation

Patella fractures, although uncommon in the context of corresponding long bone fractures, carry a disproportionately high degree of morbidity, and are often challenging to treat. As such, this study sought to evaluate the efficacy of a Krackow suture augment when compared to standard tension band fixation and cerclage suture augment in patella fracture repair. Cadaveric patella extensor mechanisms were used for biomechanical testing. Specimens were divided among 3 groups, each with a different repair technique: modified anterior tension band (MATB), MATB plus cerclage suture, and MATB plus Krackow suture. Specimens were biomechanically tested in both cyclic and maximum load settings. Mean displacement and load-to-failure forces were measured for cyclic and maximum load testing, respectively. Data was then analyzed with both one-way analysis of variance and independent t-testing. Both augmentation techniques showed improved strength in both cyclic and maximum load testing, with the Krackow suture augment showing the greatest strength. In cyclic testing, cerclage augment showed a 30% decrease in mean displacement while Krackow suture augment showed a 40% decrease when compared to the MATB repair group. Likewise, in maximum load testing, cerclage repair showed a 5% increase and Krackow a 14% increase in load-to-failure force when compared to MATB. Likely due to small sample size, the increases in repair strength did not reach statistical significance. This study provides support for the use of a Krackow suture augment in patella fracture repair, and we suggest this technique may be most useful in the setting of poor bone quality where conventional repair techniques are limited. Although failing to reach statistical significance, these results are encouraging and warrant further investigation in both biomechanical and clinical settings.