In situ modification of metal rods can be difficult. High-speed cutting discs are effective in cutting metal prominences which cause soft tissue irritation and bony erosion. Water-soluble jelly can effectively trap the metal debris generated during this cutting process.

Equipment Design↗

PubMedDate not supplied

Experiences with three distinct types of total knee joint arthroplasty.

Experience with three different designs of total knee systems indicates that generally excellent knee function can be afforded the majority of patients for many years. The identification of patients who presently cannot expect satisfactory long-term function (the young, muscular, or obese, yet otherwise normal, individual, for instance) and their exclusion as candidates is important for long-term success. The importance of postoperative limb alignment and component position is emphasized. Gross instability and great metaphyseal bone loss are identified as the indications for linked, primary, or revision total knee arthroplasty. The role of the dynamic behavior of trabecular bone is hypothesized to be of major importance in long-term prosthetic knee joint function.

Adult↗

PubMedDate not supplied

Spherocentric knee arthroplasty.

The spherocentric knee, designed to allow triaxial rotation and provide intrinsic stability, includes desirable design features of metal on high density polyethelene bearing surfaces, metal support for all plastic components, metal-cement-bone interfacing for all fixation surfaces, sufficient strength to eliminate fatigue fracture of metallic components as a potential source of failure, cam deceleration for hyperextension control, and an inverted central plastic socket which minimizes wear. The system assures a low coefficient of friction and thereby minimizes loosening. This prosthesis has been used for surgical arthroplasty in 134 knees with gross instability or severe fixed deformity or both, in which optimal results would not have been anticipated with non-articulated resurfacing prostheses. The patients have been followed for an average of nearly 3 years (range one to 5 years). Results in terms of correction of deformity, improvement of stability, range of motion, pain relief and improved function, have been outstanding. Problems of infection, loosening and fracture of adjacent bone have been less than with other intrinsically stable prostheses (hinge prostheses) and are less than most reports of non-articulated resurfacing prostheses followed for a comparable time. There have been no failures within the prosthesis. Our loose prostheses represent failures that occurred between the prostheses and the bone. The spherocentric prosthesis is the prosthesis of choice for arthroplasty of a knee with severe preoperative deformity or severe instability or both in which optimal results would not be anticipated following insertion of a resurfacing type of prosthesis.

Adult↗