Image-guided techniques improve accuracy of mosaic arthroplasty

Stephen Sebastyan, Manuela Kunz, A. James Stewart, Davide D. Bardana

Mosaic arthroplasty is a surgical technique in which a set of cylindrical osteochondral grafts is transplanted from non-load-bearing areas of the joint to repair damaged articular cartilage. Incongruity between the graft surface and the adjacent cartilage at the repair site results in inferior clinical outcomes. This paper compares technical outcome using three mosaic arthroplasty techniques (conventional, optoelectronic, and patient-specific template) on femur models. Three distinct sets of femur models with defects were created. Preoperatively, the harvest and delivery sites were planned using custom software. Five orthopedic surgeons were recruited; each surgeon performed each of the three surgical techniques on each of the three bone models with defect. During the optoelectronic trials, the instrument position and orientation were tracked and superimposed onto the surgical plan. For the patient-specific template trials, plastic templates were manufactured to fit over the defects with cylindrical holes to guide the surgical tools according to the plan. Postoperatively, the femur models were computer tomography and laser scanned. Several measures were made to compare surgical techniques: operative time; surface congruency; defect coverage; graft surface area that is proud or recessed; air volume below the grafts; and distance and angle of the grafts from the surgical plan. The patient-specific template and optoelectronic techniques resulted in improved surface congruency, defect surface coverage, and below-graft air gap volume in comparison with the conventional technique. However, the conventional technique had a shorter operative time. Image-guided techniques can improve the accuracy of mosaic arthroplasty, which could result in better clinical outcomes.