Treatment of chondral defects by hydro jet. Results of a preliminary scanning electron microscopic evaluation

Introduction: Arthroscopic methods in treatment of chondral defects aim to get smooth cartilage surfaces. Mechanical and thermal methods are used. Often the clinical results are poor or moderate. The treatment of chondral defects by using a hydro jet is an innovative measure. This study was aimed to evaluate the quality of the chondral surfaces after mechanical, thermal and hydro jet treatments in an in vitro scanning electron microscopy (SEM) study. Materials and methods: Femoral osteochondral pieces of the lateral condyle were obtained intraoperatively from patients undergoing total knee arthroplasty for primary knee OA. Partial-thickness cartilage degree II defects were smoothed by a mechanical shaver, bipolar radio frequency energy (RF) and hydro jet (84.1 KPa). SEM was carried out to evaluate the effects of the treatment. Results: Mechanical shaving produces a rough surface with groves and open lying collagen fibers. The surface, after bipolar cool ablation (coablation) was also uneven. The matrix was destroyed by massive vacuolization. Hydro jet treatment produces a relatively smooth surface without open lying collagen fibers. Conclusion: It is not possible to produce even surfaces by mechanical shaving or bipolar treatment. Hydro jet treatment allows a precise cutting which causes a relatively smooth chondral surface.