Introduction: The results of treating chondral lesions with microfracture have been well documented. The lesion heals by fibrocartilage and the functional results tend to deteriorate through time.

Hypothesis: The use of steroids an platelet rich plasma (PRP) as coadjuvants to microfracture for the treatment of full thickness chondral lesions improve the results of this marrow stimulating technique.

Purpose: To macroscopically, histologically and molecularly evaluate the repair tissue generated after treating full thickness chondral lesions with microfracture and local steroids or PRP in an animal model.

Materials: Experimental in-vivo study in 40 femoral condyles (FC) from New Zealand rabbits. Chondral lesions were induced in all the samples and divided into 4 groups:

Group 1: control, lesion left untreated.

Animals were sacrificed after 3 months and the samples were evaluated macroscopically, histologically (H and E, Toluidine Blue) and molecularly (RT-PCR for Col1 and Col2). The results were analyzed with ANOVA and Bonferroni tests (p< 0.05).

Results: Macroscopy: the control group had no healing tissue. In all the other groups there was a variable presence of a fibrocartilaginous tissue without significant differences among groups.

Histology: all the groups had the presence of fibrocartilage.

Molecular analysis: all the groups had a significantly poorer Col2/Col1 relation when compared to normal hyaline cartilage, without significant difference among groups.

Conclusions: The local use of betamethasone and PRP as coadjuvants to microfracture does not improve the macroscopical, histological and molecular results of the treatment of full thickness chondral lesions.

Introduction: Bunnell suture technique is effective for tendon repair. A modification of the classic suture technique could increase ultimate failure point (UFP) on the suture-tendon site. The purpose of this study is to evaluate UFP of regular and modified Bunnell suture techniques on in vitro porcine patellar tendons.

Methods: Porcine patellar tendon samples (N=24) were used for this study, separating them in 2 groups: Group A: classic Bunnell suture on the tendon (N=12). Group B: two perpendicular Bunnell sutures at 90° between them on the tendon (N=12). After suturing the samples, axial traction until failure on the tendon-suture site was applied on samples of both groups documenting UFP with a tension sensor device. UFP was measured and described in Newtons for all samples. Statistics: Non parametric Mann-Whitney test for independent variables was used to analyze outcomes.

Results: The UFP for group A was 224 ± 38,9 N. The UFP for group B was 307 ± 19,9 N. We found statistical differences among groups (p=0,00006).

Discussion: In this study we analyzed the UFP of classic Bunnell suture technique vs. a modification adding a second Bunnell suture perpendicular to the classic technique. The purpose of this modification is to increase the contact area between the suture and the tendon, reaching a stronger disposition at suture-tendon site. This has been documented in the UFP values obtained.

Conclusion: Adding a perpendicular Bunnell suture run in porcine ex vivo patellar tendons increases UFP in tendon repair at tendon – suture site.