Deformation and Loosening of the Tibial Component in Knee Arthroplasty with Unicompartmental Endoprostheses

Micromotion in knee arthroplasty

“…In the total material of 96 cases, there were seven cases assessed as failures and eight as acceptable according to the Lund system, while only four were not excellent or good according to the HSS-score; the HSS score being more permissive than the Lund system (Jbnson 1981). No patient in this material has been reoperated thus far.…”

“…A number of reports have been published on the deformation of plastic components (Ducheyne et al 1978, Marmor 1979, Jdnson 1981, Knutsson et al 1981, Bartel et al 1982, Scott 1982, Wright et al 1982. Such deformation allows high peak forces to be transmitted to the underlying bone, possibly increasing the risk of loosening.…”

“…It has previously been found (Marmor 1979, Knutsson et al 1981) that the 6 mm prostheses, originally on the market, were too thin and easily deformable. The cold flow in this study was larger for 9 mm than for 12 mm prostheses, which may indicate that 9 mm prostheses may also be susceptible to plastic deformation and loosening in the very long term.…”

Unicompartmental arthroplasty of the knee: Cadaver study of tibial component placement

“…Replacement of the articular surface by the comparatively small component of a unicompartmental prosthesis therefore makes optimal positioning of the load transmission important to diminish the risk of mechanical loosening (OConnor et al 1982). The correlation between the frequency of loosening and obliquely placed components in the horizontal plane has become well established (Cameron et al 1981, Knutson et al 1981, Cartier et al 1982, Shurley et al 1982. However, no reports have been published on unicornpartmental prosthesis articulation and its dependence on the positioning of the tibial component in the sagittal plane.…”

Fracture of the knee endoprosthesis: Report of three cases of tibial component failure

“…Failure of high density polyethylene prosthetic components has been described in both the hip and the knee joint (Charnley 1979, Knutson et al 1981. Fatigue fractures of the metallic femoral stem are well-known complications, especially earlier when stainless steel was used (Wroblewsky 1982).…”