Normalized and Proportionalized Cemented Femoral Stem Designs - A 10-Year Clinical Study

By William L. Jaffe, MD, and Kenneth L. Jarolem, MD

The Journal of Arthroplasty Vol. 10 Supplement 1995

Abstract: Two hundred fifteen cemented total hip arthroplasties were performed in 184 patients using normalized and proportionalized femoral stems. Normalization or stepped tapering of the stem minimizes development of tensile hoop stresses by altering force transmission from the femoral stem to the cement mantle. The proportionality of the stem was based on an anatomic study that resulted in the development of a series of prostheses achieving a more complete femoral canal fill. Patients were followed clinically and radiographically from 8 to 12 years or until revision. Average hip scores (d'Aubigne and Postel) improved for pain (3.0-5.9), function (2.9-5.5), and motion (3.3-5.5). Radiographic results demonstrated 4% incidence of loosening, a 16% incidence of cortical hypertrophy, and no femoral stem fractures. Revision rate was 3%. These results support use of this device.

Enhanced Cemented Stem Interfaces: Improved Resistance to Stem Subsidence but Increased Resistance to Stem Extraction?

By Michael T. Manley, Ph.D. and Robert G. Averill, M.S.

The Harrington Arthritis Research Center Meeting, November 1987

Abstract: Modern surface enhancements of femoral components are effective in preventing subsidence of the implant into the surrounding cement mantle. Such enhancements will reduce the non-physiologic hoop stresses in the surrounding cortical shell.

When enhanced stems need to be removed from the mantle, the force required to extract an adhesively bonded implant can be almost as much as eighty percent of the force required to induce subsidence of the stem. Revision may require that the surgeon free the implant at the bone/cement interface or break the cement away from the bonded stem. Both are difficult tasks. By comparison, the uni-directional mechanical enhancement of the interface provided by Omnifit normalization requires only some 27% of the force needed to induce subsidence, or less than half that require to remove the Precoat stem.

As revision of an implant is always a clinical consideration, a surface enhancement design which resists subsidence, without making possible future extraction of the stem from the mantle more difficult, is to be recommended. The Omnifit normalized stem provides excellent subsidence resistance, but does not make stem removal impractical.

The Femoral Component in Low-Friction Arthroplasty After Ten Years

By Luis Munuera, M.D., and Eduardo Garcia-Cimbrelo, M.D.

Clinical Orthopaedics and Related Research, Vol. No. 27-A, June 1992

In 623 low-friction arthroplasties ten years after implantation, 70 hips (18.04% after 16 years) showed loosening of the femoral component. Eighty-four percent appeared within ten years. Fracture of the stem occurred in 4.3% of cases after 16 years, and resorption over 5 mm of the femoral neck occurred in 9.3%. Calcar cysts appeared in 2.9% and endosteal cavitations in 18.04% after 16 years; both findings were related to acetabular wear greater than 2 mm. Gruen’s Type III (calcar pivot) was the least common loosening (6.8%) during the first ten years. After this time its incidence increased to 17.1%. Loosening of the femoral component was not related to age, weight, or activity. It was, however, associated with poor surgical technique, i.e., varus position (46%), cementation defects (34%), and/or femoral neck osteotomy on the lesser trochanter (36%).

Charnley Low Friction Arthroplasty in Young Patients With Osteoarthritis: A 12- to 24-Year Clinical and Radiographic Followup Study of 84 Cases

By George Hartofilakidis, MD; Theofilos Karachalios, MD; and Nikolaos Zacharakis, MD

Clinical Orthopaedics and Related Research, Number 341, pp 51-54, August 1997

The long term outcome of 84 Charnley low friction arthroplasties performed between January 1973 and December 1984 on 69 patients (84 hips) with osteoarthritis was assessed. The patients were 55 years old or younger (mean, 46 years) at the time of surgery. The probability of survival was 89.8% (range, 85.9%-93.7%) after 10 years with 69 hips at risk and 73.3% (range, 65.5%-81.1%) after 18 years with 33.5 hips at risk. Of the 84 hips in the study, 24 (28.6%) failed. Of the hips that survived, clinical results were good and excellent with Charnley scores of four or more for pain and function in all hips. Of the hips that survived, 93.3% achieved good or excellent results for movement.

Prosthesis Surface Design to Resist Loosening: Stress Normalization

By J. Pugh, Ph.D.; R. Averill; N. Pachtman; D. Bartel; W. Jaffe, M.D.

Howmedica Osteonics Technical Information Bulletin, 1980

Abstract: The design reported produces a significant increase in resistance to subsidence relative to conventional designs. Due to the nature of the imbrications, there is no increase in extraction force should this prosthesis require removal. Since the finite element modelling shows that deleterious hoop stresses are not generated until slipping occurs, this new design offers the potential for extended useful life of the cement, which we and others consider to be the weak link in the force transmission system.

The Cement Mantle in Total Hip Arthroplasty: Analysis of Long-Term Radiographic Results

By Edward Ebramzadeh, M.S., Augusto Sarmiento, M.D., Harry A. McKellop, Ph.D., Adolfo Llinas, M.D., and William Gogan, M.D., Los Angeles, California

The Journal of Bone and Joint Surgery, Incorporated, Vol. 76-A, No. 1, January 1994

Investigation performed at the Orthopaedic Biomechanics Laboratory of the J. Vernon Luck, Sr., Orthopaedic Research Center, Los Angeles Orthopaedic Hospital, Los Angeles; the Biomaterials Group, Department of Handicap Research, University of Göteborg, Göteborg; and the Department of Orthopaedics, University of Southern California, Los Angeles

Abstract: The correlation between the thickness of the cement mantle, the medullary canal fill, and the orientation of the stem and the long-term radiographic outcome of 836 cemented femoral components in patients who had a primary total hip replacement was assessed with use of survival analysis over a twenty-one-year follow-up period. The femoral stems of hips that had a two to five-millimeter-thick cement mantle in the proximal medial region had a better outcome than stems implanted with a thicker or thinner cement mantle. Stems in femora with less than two millimeters of proximal medial cancellous bone had a better outcome than stems in femora with thicker cancellous bone. Stems that filled more than half of the medullary canal had better radiographic results than those that filled half or less. Progressive loosening, fracture of the cement, and radiolucent lines at the stem-cement or bone-cement interfaces were more likely to develop in stems that were oriented in more than 5 degrees of varus than in those in neutral or valgus. The noted correlations were true whether the stem was made of titanium alloy or of stainless steel. The results of this study emphasize the importance of careful preoperative planning in total hip arthroplasty done with cement and provide guidelines for the selection of the shape, size, and position of the stem.

Early Loosening Reported With Precoated Stem

By Richard F. Santore, MD, Coronado, Calif.

Orthopaedics Today, Nov. 1997, Vol 17, No. 11

Short-term loosening associated with a precoated matte-finished femoral prosthesis has led a surgeon, Richard F. Santore, MD, to call for the abandonment of use of implant in total hip arthroplasty.Richard F. Santore, MD reported his experience with the Centralign Precoat Femoral Component, manufactured by Zimmer, at the 10th annual meeting of the International Society for Technology in Arthroplasty.

Total Hip Arthroplasty in Patients Under 50 Using Contemporary Cement Techniques

By W. Timothy Ballard, MD, Iowa City, IA, John J. Callaghan, MD, Iowa City, IA, Patrick M. Sullivan, MD, Des Moines, IA

Presented at the 61st Annual Meeting of the AAOS, New Orleans, LA, February 24-March 1, 1994.

Forty-three primary total hip arthroplasties were performed using second-generation cement techniques in patients under 50 years of age. At minimum ten year follow-up, the combined incidence of definite or probably radiographic loosening and revision for aseptic loosening was 35.7% for the acetabular component and 14.3% for the femoral component. All of the loose femoral components either occurred in patients with aseptic necrosis secondary to renal failure or were graded definitely loose based solely on zone 1 femoral debonding of a polished stem. These results show significant improvement using contemporary cement techniques in this age group.

Charnley Total Hip Arthroplasty with Use of Improved Techniques of Cementing
The Results After a Minimum of Fifteen Years of Follow-up

By Steven M. Madey, MD, John J. Callaghan, MD, Jason P. Olejniczak, BA, Iowa City, Iowa; Devon D. Goetz, MD, and Richard C. Johnston, MD, Des Moines, Iowa

The Journal of Bone and Joint Surgery, Vol. 79-A, No. 1, January 1997

Investigation performed at the Iowa Methodist Medical Center, Des Moines, and the University of Iowa College of Medicine, Iowa City

Abstract: Three hundred and fifty-seven consecutive Charnley total hip arthroplasties were performed in 320 patients with use of a so-called second-generation technique of cementing between July 1976 and June 1978. This technique includes use of a distal femoral intramedullary cement plug, hand-mixing of the cement, and use of a cement gun to deliver the cement into the femoral canal in a retrograde fashion. At the time of the latest follow-up evaluation, a minimum of fifteen years after the arthroplasty, 130 patients (142 hips) were still alive, 189 patients (214 hips) had died, and one patient (one hip) had been lost to follow-up. A radiograph was made for 116 (82 per cent) of the 142 hips in the 130 surviving patients.

Of the 356 hips that had not been lost to follow-up, thirty-three (9 per cent) had had a revision and two (1 per cent), a Girdlestone resection arthroplasty during the follow-up period. Nineteen hips (5 per cent) were revised because of aseptic loosening of the femoral or acetabular component, or both (two hips); seven (2 per cent), because of loosening with infection; and seven (2 per cent), because of dislocation. The two resection arthroplasties were performed because of loosening with infection; both were done in patients who died before the time of the latest follow-up evaluation. Of the 142 hips in the 130 patients who were alive at a minimum of fifteen years, twenty-two (15 per cent) had been revised; fifteen (11 per cent), because of aseptic loosening; three (2 per cent), because of loosening with infection; and four (3 per cent), because of dislocation.

Revision of the femoral component because of aseptic loosening (excluding components that were revised because of dislocation or infection) was performed in four (1 per cent) of the entire series of 356 hips and in three (2 per cent) of the 142 hips in the 130 patients who survived for at least fifteen years. Two of the 356 hips and two of the 142 hips had aseptic loosening of the acetabular as well as the femoral component at the time of the revision. Loosening of the femoral component, defined as aseptic loosening leading to revision or as definite or probable radiographic loosening, occurred in ten (3 per cent) of the 356 hips and in six (5 per cent) of the 116 hips for which radiographs were made at a minimum of fifteen years.

The acetabular component was revised because of aseptic loosening in seventeen (5 per cent) of the entire series of 356 hips and in fourteen (10 per cent) of the 142 hips in the 130 patients who survived for at least fifteen years. The acetabular component loosened without infection in forty-one (12 per cent) of the 356 hips and in twenty-six (22 per cent) of the 116 hips for which radiographs were made at a minimum of fifteen years. In two of these patients, the femoral component was also revised. Thus, of the entire series of 356 hips, two had a revision of the femoral component alone because of aseptic loosening; fifteen, a revision of the acetabular component alone; and two, a revision of both components. Of the 142 hips in the 130 patients who survived for at least fifteen years, one was revised for loosening of the femoral component alone; twelve, for loosening of the acetabular component alone; and two, for loosening of both components.

These findings demonstrate long-term durability of fixation of the femoral component but less reliable fixation of the acetabular component, even when the surgeon is experienced and improved techniques of cementing are used.

Cemented Total Hip Replacement in Patients Who Are Less than Fifty Years Old

By Dennis K. Collis, M.D., Eugene, Oregon

The Journal of Bone and Joint Surgery, Vol. 66-A, No. 3., March 1984

Abstract: Forty-five cemented total hip replacements in thirty-eight patients who were less than fifty years old were followed with physical examinations and radiographs for five to eleven years (average, 7.3 years) after surgery. The average age of the patients at the time of surgery was 40.7 years. The average Iowa hip rating at follow-up was 91.9 points (range, 58 to 100 points). No surgical deaths, infections, or dislocations were encountered. All of the patients had been repeatedly advised to avoid running, jumping, heavy labor, and lifting more than forty pounds (eighteen kilograms). Revision of a prosthetic component was necessary in four hips (8.9 per cent); all of the revisions were successful. Radiolucent lines were seen about the acetabular components of thirty-one hips but in only three (6.6 per cent) were these judged to be progressive bone-cement demarcation lines. Only one of those three hips was symptomatic. three hips (6.6 per cent) also had subsidence of the femoral component into the femoral canal, but only one hip was symptomatic. Resorption of the medial aspect of the proximal end of the femur was seen in five hips, the maximum resorption being three to five millimeters. I have concluded that cemented total hip arthroplasty can give acceptable results in patients who are thirty to fifty years old, and that the result can be reasonably long-lasting if the patients are willing to avoid strenuous activity.

Improved Cementing Techniques and Femoral Component Loosening in Young Patients with Hip Arthroplasty: A 12-Year Radiographic Review

By Robert L. Barrack, Richard D. Mulroy, Jr., William H. Harris, From the Massachusetts General Hospital and Harvard Medical School, Boston

The Journal of Bone and Joint Surgery, Vol. 74-B, No. 3, May 1992

To assess the effect of improved methods of femoral cementing on the loosening rates in young patients, we reviewed 50 ‘second-generation’ cemented hip arthroplasties in 44 patients aged 50 years or less. The femoral stems were all collared and rectangular in cross-section with rounded corners. The cement was delivered by a gun into a medullary canal occluded distally with a cement plug. A clinical and radiographic review was undertaken at an average of 12 years (10 to 14.8) and no patient was lost to follow-up.

No femoral component was revised for aseptic loosening, and only one stem was definitely loose by radiographic criteria. By contrast, 11 patients had undergone revision for symptomatic aseptic loosening of the acetabular component and 11 more had radiographic signs of acetabular loosening.