Cement penetration in the proximal femur does not depend on broach surface finish.

In a cadaver study, we prepared 29 paired human cadaver femora using 3 different broaches of identical geometry but different surface characteristics. In one group of 20 pairs, preparation with chipped-toothed broaches was compared to diamond-shaped broaches; in the other group of 9 pairs, polished tamps for compaction of cancellous bone were compared with chipped-tooth broaches. Cancellous bone was irrigated with 1 liter pulsed lavage. The specimens were embedded in specially-designed pots. Palacos R and Simplex bone cements were used. After vacuum mixing, the cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3,000 N. Radiographs were taken and horizontal sections were obtained at predefined levels using a diamond saw. Microradiographs were taken, digitized and analyzed to assess cement penetration into cancellous bone. In 6 of 9 femora prepared using smooth tamps, femoral fractures occurred despite careful preparation technique. The microradiographic evaluation showed no significant morphometric differences between diamond and chipped-tooth or between polished and chipped-tooth broaches with regard to cement penetration into cancellous bone. Therefore, in the presence of pulsed lavage, one finds no significant effect of broach surface characteristics on cement penetration into cancellous bone of the proximal end of the femur.

[Effect of a rasp surface on cement penetration in paired cadaver femurs]. / Einfluss der Raspeloberfläche auf die Zementpenetration an gepaarten Leichenfemora.

AIM: The purpose of this investigation was to study two different broach surface designs with regard to cement penetration into human cancellous bone. METHODS: In a cadaver study 15 paired human cadaver femora were prepared using broaches of identical geometry but different surface characteristics. All left femora were prepared using chipped toothed broaches, all right femora using diamond shaped broaches. Cancellous bone was irrigated with 1 liter pulsed lavage. The specimens were imbedded in specially designed pots. Bone cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3000 N. Radiographs were taken and horizontal sections were obtained at predefined levels using a diamond saw. Microradiographs were taken and analyzed using image analysis to assess cement penetration into cancellous bone. RESULTS: Pressure curves recorded during cement pressurisation were comparable. The microradiographic evaluation revealed no significant morphometric differences in the different groups with regard to cement penetration into cancellous bone. These findings were similar in all sections obtained. CONCLUSIONS: A standardized model was developed allowing comparison of cement penetration into cancellous bone depending on bone preparation. In the presence of pulsed lavage there is no significant influence of broach surface characteristics on cement penetration into cancellous bone of the upper end of the femur.

Ultrasonic technology in revision joint arthroplasty.

The development of ultrasonically driven tools for revision joint arthroplasty is presented. The data represent seven-years' experience and include information from laboratory investigation and clinical experience from 20 surgical cases. Whole bone torsional strength studies reveal no decrease in strength parameters after the removal of cement ultrasonically. Comparison studies demonstrate that ultrasonic tools allow more rapid completion of cement and prosthesis removal than traditional manual tools. Histologic studies using an in vivo canine model demonstrate no deleterious effects to endosteal bone where cement had been removed by ultrasound. Clinical studies indicate that the use of ultrasound facilitates the surgery and causes no cortical perforations; the creation of cortical windows was not necessary in all cases. Ultrasound is safe and efficacious in cement and prosthesis removal during revision surgery.

Revision arthroplasty facilitated by ultrasonic tool cement removal. Part II: Histologic analysis of endosteal bone after cement removal.

This conclusion of a two-part series examines the effects of ultrasonic cement removal from canine femurs on the underlying endosteal bone. The purpose of the investigation was twofold: to qualitatively assess the immediate in vivo effects on bone of direct coupling as a method of ultrasonic prosthesis removal, and to determine the immediate and delayed histologic responses of cortical bone to ultrasonic cement removal as well as compare the response after cement removal by high-speed burr instrumentation. This histologic study of an in vivo model demonstrated no significant cortical bone damage with the use of ultrasonically driven tools. The authors conclude that this method for the removal of bone cement and securely fixed prostheses is safe and efficacious.

Revision arthroplasty facilitated by ultrasonic tool cement removal. Part I: In vitro evaluation.

Ultrasonically driven tools (UDTs) have been developed to facilitate removal of bone cement and securely fixed cemented components during revision arthroplasty. A two-part study was performed to evaluate the efficacy and safety to these tools. Heat generation at the endosteal surface during prosthesis and cement removal with a UDT was examined in an in vitro human femoral revision model. The histologic changes produced by the UDT at the endosteal surface were evaluated with an in vivo canine model. The heat generation studies demonstrated one-degree (C) temperature elevations at the endosteal surface during cement removal. We conclude that UDT use is safe and effective in the removal of cement and secure prostheses during revision total hip arthroplasty.

Fat embolism syndrome following the intramedullary alignment guide in total knee arthroplasty.

Fat embolism syndrome (FES) is a well-known complication of total hip arthroplasty (THA). FES occurs less frequently in total knee arthroplasty (TKA) than in THA. A 67-year-old woman developed FES after placement of the intramedullary femoral alignment guide during TKA. The diagnosis is based upon a subtle, but significant change in the oxygen saturation after placement of the guide. This potentially fatal complication may be avoided with a simple precautionary step of intramedullary canal marrow aspiration prior to placement of the alignment guide pin.

The use of ultrasonic tools in revision arthroplasty procedures.

Cemented and uncemented prostheses removed from bone using ultrasonic tools were evaluated grossly, microscopically, and microradiographically. The findings in this study indicate that application of an ultrasonic tool to the intramedullary canal is a safe method for removal of a variety of components. In addition, when the energy is coupled directly to the metallic component, it can be separated from the cement-bone or prosthesis-bone interface instantly.

Chiari osteotomy in cerebral palsy.

Twelve cerebrospastic patients underwent 13 Chiari osteotomies for the treatment of subluxed or dislocated hips. Twelve of these 13 hips were reexamined 24-80 months later. Ten patients had painless located hips. The two failures had pelvic obliquity that resulted in redislocation.