Combined Unicompartmental Knee Arthroplasty and Trochlear Porous Calcium Carbonate Scaffold Implantation: Surgical Technique.

Unicompartmental knee arthroplasty (UKA) has emerged as a relatively joint-preserving option for younger, active patients with advanced osteoarthritis (OA) isolated to the medial or lateral compartment. The indication for UKA is more controversial in patients with mixed multi-compartment disease, that is, advanced knee OA in a single compartment coexisting with more focal disease in a separate location, most frequently the trochlea. Whereas some surgeons advocate ignoring patellofemoral compartment disease and proceeding with UKA, others are more cautious and indicate total knee arthroplasty (TKA) because of concerns that untreated defects in another compartment may lead to suboptimal outcomes. Because surgeons often have different age and activity thresholds for indicating UKA versus TKA, some patients are limited to-often ineffective-conservative care because the extent of disease is deemed too great for UKA yet they are considered too young for TKA. CartiHeal Agili-C (Smith & Nephew, Andover, MA), a porous calcium carbonate scaffold made from coral, promotes cartilage regeneration and offers an off-the-shelf biologic solution for osteochondral repair. It has received Food and Drug Administration approval for the treatment of degenerative defects in early OA. Combining UKA with CartiHeal Agili-C implantation offers the potential to preserve more of the native joint in patients with mixed multi-compartment disease.