No abstract

We reviewed 134 primary noncemented porous-coated total hip replacements in 125 patients: 64 were DePuy AML prostheses, 20 were Howmedica PCA and 50 were Implant Technology LSF. The prostheses had been in situ for an average of 36 months, 40 months and 24 months respectively. The average pre-operative Harris hip scores were 38.2 for AML, 33.2 for PCA, and 41.0 for the LSF prostheses. The average postoperative scores were 80.7 for AML, 83.8 for the PCA, and 91.5 for LSF. Thigh or groin pain associated with the prosthesis was present in 30% of AML, 30% PCA and 8% of the LSF cases. The clinical and radiographic review showed better early results with the LSF prostheses than the others; this seemed to be related to the implant design, which provided improved initial stability and more physiological transfer of load.

No abstract

This study evaluated the interaction of osteosynthetic plates to adjacent tissue. Eleven patients had 13 plates removed with simultaneous biopsies of the adjacent soft tissue. Four patients had pain localized to the area of the plate and 11 patients had routine removal or removal for fracture nonunion. Each plate was graded on a 0-5 point scale for the amount and severity of corrosion present at the screw-plate interface. The adjacent tissue was fixed in formalin and stained with hematoxylin and eosin. The tissue reaction was graded on a 0-5 point scale based on the inflammatory response. A positive correlation of corrosion and tissue reaction was found that was significant at p less than 0.005 in the asymptomatic group. The other good correlation showed that tissue reaction tends to decrease with time at p less than 0.005. There was no correlation of corrosion with tissue reaction in the symptomatic removal group. All patients with pain adjacent to the plates were relieved by implant removal. The findings suggest that stainless steel is minimally toxic to human tissue in most circumstances and that the toxic products are well tolerated. There was a significant group (4/11) that showed a different pattern of tissue response which did not appear to be toxic response. We do not recommend routine implant removal to prevent metal toxicity; however, there is a group of patients who have pain in the area of the implant that may be caused by an allergic reaction and is relieved by implant removal.