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Kevin Cheng

Publications and source records attributed to Kevin Cheng.

4 recordsLinked to original sources

Osteolysis caused by tibial component debonding in total knee arthroplasty.

Late failure of total knee arthroplasties usually results from ultrahigh molecular weight polyethylene wear or implant loosening. Early failure from osteolysis is uncommon. However, we treated a patient with a failed total knee arthroplasty from osteolysis that developed 2 years postoperatively. The failure was associated with tibial component debonding from the cement mantle with abundant cement and metal debris. Although there was some third-body debris in the ultrahigh molecular weight polyethylene insert surface, the insert wear was not extensive. Although abundant cement and metal debris were found in the periarticular soft tissues, no ultrahigh molecular weight polyethylene was seen in histologic specimens under polarized light. The osteolysis seems to have been caused primarily by debris generated from debonding and torsional motion at the tibial baseplate-cement interface rather than the bearing surface. Although this failure mechanism has been well recognized in cemented total hip arthroplasties, it has not been reported to be a substantial cause of failure in total knee arthroplasties.

Aged↗

The effect on anterior column loading due to different vertebral augmentation techniques.

BACKGROUND: Vertebral compression fractures are a significant cause of morbidity amongst the elderly, resulting in pain, kyphosis, decreased mobility, and often depression. The two most popular operative treatments of compression wedge fractures are vertebroplasty and kyphoplasty, however, which method leads to restoration of normal spinal loading is unknown. METHODS: A cadaveric thoracolumbar spine model was fractured and then treated using one of two techniques: vertebroplasty or kyphoplasty. Three non-destructive loading regimes were applied to the intact, fractured and treated cases. Sub-adjacent nuclear pressure, used as a measure of anterior column loading, was determined for each experimental variant and loading case. FINDINGS: The data indicate that nuclear pressure was substantially reduced after the spine was fractured. These pressures were minimally increased after treatment, however, not to the level of the pre-fractured condition. In all loading cases, there were no significant differences between the two treatment types. INTERPRETATION: While our data show that both vertebroplasty and kyphoplasty allow the disc to generate higher nuclear pressures, neither treatment increased nucleus pulposus pressure above the level of the intact state. This directly relates to the clinical condition in that adjacent segment fractures sustained subsequent to either treatment is likely the result of overall disease progression, and not a direct result of the intervention.

Adult↗