USE OF GROMMETS FOR FLEXIBLE IMPLANT RESECTION ARTHROPLASTY OF THE METACARPOPHALANGEAL JOINT

In 1987, after 11 years of research, press fit titanium circumferentia l grommets were introduced for arthroplasty of the metacarpophalangeal joint to protect the flexible hinge implant midsection from sharp bon y edges and shearing forces that can initiate implant abrasions and te ars leading to implant fracture and formation of silicone wear particl es. The effectiveness of the titanium circumferential grommets was ass essed by comparing the results of 170 metacarpophalangeal joint implan t (high performance) arthroplasties performed with (139 joints) and wi thout (31 joints) grommets in 38 patients presenting an average 5.8 ye ars followup. Both groups obtained pain relief, functional motion, sta bility, and correction of deformity. There was no evidence of particul ate synovitis or infection. There were four implant fractures (12.9%) in the nongrommet group, and one (0.7%), because of implant rotation, in the grommet group. Although favorable bone remodeling was observed in both groups, the grommet group showed greater bone preservation at the metaphyseal and midshaft levels and increased intramedullary bone production around the implant stems. The results depend on appropriate surgical staging, meticulous operative and postoperative techniques, severity and progression of disease, and implant durability. The circu mferential grommets safely and effectively protect the implant to bone interface to further the durability of implant arthroplasty of the me tacarpophalangeal joint.