Eric L. Masterson

The cement mantle in the exeter impaction allografting technique

The postoperative radiographs of 35 patients who underwent impaction allografting of the proximal femur were reviewed. Of Gruen zones that could be clearly visualized, 39.9% contained areas where cement was absent. Even when an adequate mantle was present, cement voids were commonly seen. These cement mantle deficiencies were confirmed in a series of cadaveric impaction allografting procedures. They appear to be a consequence, at least in part, of an inadequate differential between trial and actual component sizes. Additionally, 4 patients were identified with significant component migration secondary to radiographically visible cement mantle fractures within the first 6 months of surgery. It is concluded that the surgical technique requires modification to ensure a more consistent cement mantle and clinical result.

Impaction allografting with cement for the management of femoral bone loss.

Impaction allografting with cement is the only technique currently available which reverses the diminution of bone stock that occurs in a revision hip arthroplasty, and as such, has great potential. It is particularly appropriate in the younger patient, though older patients may also benefit from the technique. Although the short term results are encouraging, there is a need for further basic science research to determine the optimal graft material and prosthesis design. Refinements in surgical instrumentation and technique will continue to improve the predictability of the clinical result and expand the indications for this important addition to the available options in revision hip arthroplasty.

The cement mantle in femoral impaction allografting: A comparison of 3 systems from 4 centres

An analysis of the cement mantle obtained with the Exeter impaction allografting system at one centre showed that it was either deficient or absent in almost 47% of Gruen zones. We therefore examined the mantle obtained using this system at another hospital and compared the results with those from the CPT and Harris Precoat Systems at other centres. The surgical indications for the procedure and the patient details were broadly similar in all four hospitals. There was some variation in the frequency of use of cortical strut allografts, cerclage wires and wire mesh to supplement the impaction allograft. Analysis of the cement mantles showed that when uncertain Gruen zones were excluded, the incidence of zones with areas of absence or deficiency of the cement was 47% and 50%, respectively, for the two centres using the Exeter system, 21% for the CPT system and 18% for the Harris Precoat system. We measured the difference in size between the proximal allograft impactors and the definitive prosthesis for each system. The Exeter system impactors are shorter than the definitive prosthesis and taper sharply so that the cavity created is inadequate, especially distally. The CPT proximal impactors are considerably longer than the definitive prosthesis and are designed to give a mantle of approximately 2 mm medially and laterally and 1.5 mm anteriorly and posteriorly. The Harris Precoat proximal impactors allow for a mantle with a circumference of 0.75 mm in the smaller sizes and 1 mm in the larger. Many reports link the longevity of a cemented implant to the adequacy of the cement mantle. For this reason, femoral impaction systems require careful design to achieve a cement mantle which is uninterrupted in its length and adequate in its thickness. Our results suggest that some current systems require modification.

THE CLASSIFICATION AND RADIOGRAPHIC EVALUATION OF BONE LOSS IN REVISION HIP ARTHROPLASTY

Many classification systems have been described over the past 10 years for bone loss that is found in association with the failed hip arthroplasty. Most are based on assessments of bone stock that are made intraoperatively. Good-quality plain radiography is the most useful preoperative investigation and provides important information regarding the residual bone stock. There is a need for critical appraisal of the validity of classification systems currently in use and the development of a consensus system that will permit comparison between the published results of different techniques.

Impaction allografting of the proximal femur using a Charnley-type stem: A cement mantle analysis

The preoperative and early postoperative radiographs of 50 patients undergoing femoral impaction grafting with a modified Charnley stem and dedicated impaction grafting instrumentation were assessed to determine the predictability of the cement mantle being produced. The minimal cement mantle thickness was >2 mm in 76.7%, <2 mm in 12.7%, and absent in 10.7% of Gruen zones analyzed. There was no obvious zonal distribution to the areas of adequate or inadequate cement thickness. These values compare favorably with the results of other systems, and this may be due, in part, to a greater differential between the size of the graft impactors and the definitive prostheses.

Surgical approaches in revision hip replacement.

&NA; Revision hip arthroplasty will be performed with frequency in the future. A successful outcome depends on careful preoperative planning, and a key component of that plan is the surgical approach. The choice of the approach should be based on the indication for revision, the particular implant to be removed, the presence of acetabular or femoral bone loss, previous surgical approaches used, and the preferences and training of the surgeon. For simple revision procedures, one of the standard approaches used in primary hip arthroplasty may be adequate. More complex cases may necessitate an extended exposure or one of the techniques developed specifically for revision arthroplasty. No single approach is suitable for all revision procedures, and the surgeon must be familiar with a range of exposures if the clinical result is to be optimized.

Treatment of Infection at the Site of Total Hip Replacement*(dagger)

The modern era of total hip arthroplasty is little more than thirty years old, and during that time the procedure has proved to be highly effective in improving the physical function, social interaction, and over-all health of millions of patients47. Initially, the procedure was associated with notable rates of infection16, but these have since been reduced considerably with measures such as prophylactic antibiotics, ultraclean-air operating rooms, and careful selection of patients36. However, this reduction in the prevalence of postoperative deep infection has been accompanied by a steady increase in the frequency with which the operation is performed. It has been estimated that the prevalence of infection after all total hip replacements performed on Medicare patients in the United States, between 1986 and 1989, was approximately 2.3 per cent (5370 of 236,140)66. Extrapolation of these figures to the estimated 200,000 such procedures that are performed annually in the United States suggests that more than 4000 new cases of periprosthetic hip infection need treatment annually. These figures do not distinguish between infections that originated in the operating room and those of hematogenous origin. The total represents a sizable number of dissatisfied patients for whom the success or failure of treatment to eradicate the infection will have major implications for their quality of life. In addition to the obvious human cost of an infection at the site of a total hip prosthesis are the considerable financial implications for the individual or the institution that must pay for the treatment. Revision hip operations necessitate a longer stay in the hospital than do primary procedures25. In addition, the operating time is longer, the blood loss is greater, and the rate of complications as well as the cost of implants are higher7. A number …

THE CEMENT MANTLE IN FEMORAL IMPACTION ALLOGRAFTING

An analysis of the cement mantle obtained with the Exeter impaction allografting system at one centre showed that it was either deficient or absent in almost 47% of Gruen zones. We therefore examined the mantle obtained using this system at another hospital and compared the results with those from the CPT and Harris Precoat Systems at other centres. The surgical indications for the procedure and the patient details were broadly similar in all four hospitals. There was some variation in the frequency of use of cortical strut allografts, cerclage wires and wire mesh to supplement the impaction allograft. Analysis of the cement mantles showed that when uncertain Gruen zones were excluded, the incidence of zones with areas of absence or deficiency of the cement was 47% and 50%, respectively, for the two centres using the Exeter system, 21% for the CPT system and 18% for the Harris Precoat system. We measured the difference in size between the proximal allograft impactors and the definitive prosthesis for each system. The Exeter system impactors are shorter than the definitive prosthesis and taper sharply so that the cavity created is inadequate, especially distally. The CPT proximal impactors are considerably longer than the definitive prosthesis and are designed to give a mantle of approximately 2 mm medially and laterally and 1.5 mm anteriorly and posteriorly. The Harris Precoat proximal impactors allow for a mantle with a circumference of 0.75 mm in the smaller sizes and 1 mm in the larger. Many reports link the longevity of a cemented implant to the adequacy of the cement mantle. For this reason, femoral impaction systems require careful design to achieve a cement mantle which is uninterrupted in its length and adequate in its thickness. Our results suggest that some current systems require modification.

Conversion of Girdlestone Arthroplasty to Total Hip Replacement

Girdlestone arthroplasty is currently used as a generic term to describe any surgical procedure about the hip joint, either primary or secondary, that involves excision of the femoral head and neck and results in a pseudarthrosis of the joint. The most common indication for the procedure in contemporary Western practice is as a definitive or interval operation for the management of an infected hip prosthesis.1–6 Less common indications include septic arthritis,7 aseptic loosening of a hip prosthesis where further reconstruction is not considered,8 cerebral palsy or other chronic neurologic conditions with chronic hip dislocation and, rarely, certain tumor resections in the region of the hip joint. Prior to the emergence of total hip replacement as the treatment of choice for advanced degenerative arthritis of the hip joint, satisfactory results were reported following management by joint resection, especially in cases with markedly reduced joint mobility and fixed contractures.9 In countries with limited medical facilities and funding, resection arthroplasty remains a treatment option, albeit not ideal, for femoral neck fractures and degenerative hip joint disease.10