Femoral fixation in primary total hip arthroplasty.

We have presented the major advantages of using femoral components that have porous coating over the entire stemmed portion and have a cylindrical distal shape. The advantages of a stem with these design features also are reflected in the changing pattern of hip implant usage. A decade ago, the most frequently used porous-coated implants were those designed predominantly for metaphyseal fixation. At that time, the only commercially available, extensively porous-coated stem with a cylindrical distal stem shape was the anatomic medullary locking (AML) prosthesis. Currently, the most commonly used porous-coated prosthesis is the extensively porous-coated AML. Virtually all implant manufacturers now make a stem with design features similar to the AML. While concerns about stress shielding and prosthesis removal remain, they have not proven to be a clinical problem in our experience. We have used these stems in all of our primary total hip arthroplasties for 20 years and continue to do so.

Artroplastia total do quadril com prótese näo cimentada / Total cementless hip arthroplasty

Os autores fizeram uma avaliaçÒo retrospectiva em 53 próteses näo cimentadas, com seguimento de 10 a 10,5 amos, realizadas no período de abril a setembro de 1986. A idade esteve compreendida entre 18 e 64 anos, com média de 39 anos. A avaliaçäo objetiva foi feita pelo mÚtodo de Merle D'Aubigné e Postel e a subjetiva, pelo grau de satisfaçÒo de cada paciente, de acordo com um questionário modificado e adaptado a nossas condiçöes socieconômicas. Os bons resultados nas próteses de Galante após esse período representaram apenas 39,62 por cento; os regulares, 26,41 por cento; e os maus, 33,96 por cento. Nas de Roy-Camille encontramos 71,3 por cento de bons, 15,2 por cento de regulares e 13,5 por cento de maus. Em nenhuma delas encontramos resultados excelentes ou muito bons. Foram realizadas três revisöes com substituiçäo dos dois componentes (Galante) duas com substituiçäo apenas do componente femoral (Galante) e cinco do acetabular (Roy-Camille, duas e Galante, três). Em um paciente, com prótese de Roy-Camille, foram retirados os dois componentes, por infecçäo profunda. Das substituiçöes, cinco foram por desprendimento asséptico, três por infecçäo e duas por fratura do fêmur ou do componente. Em nossas observaçöes, durante dez anos, comprovamos que as próteses sÒo cimentadas, utilizadas em nosso serviço, apresentaram resultados bisonhos, que nÒo justificaram seu emprego. Mesmo nos casos considerados bons e regulares, encontramos 59,7 por cento de sinais radiológicos de comprometimento dos componentes, conseqüência da açäo dos débris. Com os materiais atualmente disponíveis, comprovadamente nocivos à organizaçäo estrutural do organismo humano, caminhamos sem direçäo e sem futuro. Ao indicarmos uma prótese total do quadril atualmente, estamos assumindo näo somente uma responsabilidade, mas, acima de tudo, uma responsabilidade jurídica, pelos danos que poderäo ocorrer no futuro ao paciente.

Artroplastia total do quadril com prótese cimentada de Charnley: avaliaçäo clínico-radiológica com seguimento mínimo de dez anos no HTO / Total hip arthroplasty with Charnley's cemented prosthesis: evaluation clinical-radiological with follow-up of 10 years in HTO

Foi realizada reavaliaçäo clínica e radiológica de 92 pacientes somando um total de 111 casos de artroplastia total do quadril com utilizaçäo da prótese cimentada de Charnley, entre 1975 e 1985, no Serviço de Quadril do Hospital de Tráumato-Ortopedia Dr. Mßrio Jorge, com seguimento mínimo de dez anos. Um total de 60 por cento das próteses cimentadas estäo estáveis, sem sinais clínicos ou radiológicos de soltura. Foram encontradas evidências de afrouxamento nos outros 40 por cento, das quais 64 por cento foram do componente acetabular, 23 por cento do femural e 23 por cento em ambos os componentes. Esse percentual está de acordo com a estatística presente nos artigos de toda a literatura mundial, permanecendo a prótese cimentada de Charnley como uma grande alternativa para as artroplastias totais do quadril.

Comparaçäo das abordagens ântero-lateral e posterior em artroplastia total primária de quadril / Comparison between the anterolateral and posterior approaches in total primary hip arthroplasty

Neste estudo retrospectivo foram selecionados 184 pacientes submetidos Ó artroplastia total primßria de quadril, 95 pela abordagem Ôntero-lateral e 89 pela posterior, de junho de 1993 e junho de 1997. Os eventos avaliados foram parÔmetros perioperatórios (tempo cirúrgico, de internaçÒo hospitalar e intervalo entre cirurgia e alta, sangramento e necessidade de transfusÒo sanguÝnea) e complicações (trombose venosa profuda, embolia pulmonar, lesÒo de nervo perifÚrico, instabilidade da prótese e outros). Os dois grupos nÒo diferiram quanto aos indicadores prÚ-operatórios. Os pacientes de abordagem posterior tiveram tempo cirúrgico reduzido )p<0,001), alÚm de apresentarem menores sangramentos no transoperatório (p<0,05) e necessidade de transfusÒo transoperatória (p<0,001). Os grupos nÒo diferiram quanto aos demais parÔmetros e complicações, que tiveram baixa freqüÛncia. A abordagem posterior tem sido empregada com sucesso pelo Grupo de Cirurgia do Quadril do Hospital de ClÝnicas de Porto Alegre, sendo uma excelente opçÒo de acesso cirúrgico para artroplastia total do quadril.

Bone-graft augmentation for acetabular deficiencies in total hip arthroplasty. Results of long-term follow-up evaluation.

The results of 102 consecutive primary and revision total hip arthroplasties performed with bone-grafting for acetabular bone deficiencies were reviewed at an average of 10.2 years (range, 4-18.6) after surgery. Ninety-one percent had structural bone defects and 57% had underlying developmental dysplasia of the hip. Overall acetabular revision rates for aseptic loosening were 8% at 5 years and 26% at 10 years. In addition, in the patients with developmental dysplasia who had primary hip arthroplasties, acetabular revision rates for aseptic loosening were 3 and 18% at 5 and 10 years, respectively. Ninety-six percent of all uninfected grafts incorporated. Bulk grafts fared better than particulate grafts. No difference in failure rate was noted between primary and revision hip arthroplasty, type of deficiency, or amount of graft coverage. Although early results are encouraging, acetabular failure increased significantly with longer follow-up evaluation; however, graft incorporation was successful and facilitated subsequent revision surgery.

Vastus-Psoas release for acetabular exposure in revision hip surgery.

A technique is presented for wide exposure of the acetabulum for revision total hip arthroplasty surgery in the presence of a solidly fixed, modular, or monoblock femoral component without the need for trochanteric osteotomy. The technique involves release of the proximal portion of the vastus lateralis, vastus intermedius, and vastus medialis muscles and the iliopsoas tendon form the femur and placement of the femoral head/neck posterior to the acetabulum. The exposure afforded by this release usually precludes the need for trochanteric osteotomy and/or removal of a well-fixed femoral component in revision surgery that is being done for isolated loosening of acetabular components, thereby decreasing operative time, morbidity, and the risks of complication of trochanteric osteotomy.

Charnley low friction arthroplasty in young patients with osteoarthritis. A 12- to 24-year clinical and radiographic followup study of 84 cases.

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.

Rationale of a flexible press fit cup in total hip replacement. 5-year followup in 280 procedures.

A consecutive series of 280 total hip replacements in 261 patients using the Press Fit Cup with a minimum followup of 5 years is presented. The Press Fit Cup is a nonmodular acetabular component with a porous coating made of titanium fibers. It has one peg and is 1.5 mm oversized with biradial eccentricity. It has a flattened pole area, requires no screw fixation, and partially preserves elasticity. The mean age was 71 years for women, 70 years for men. Forty-seven patients (49 hips) died before the 5-year review, and five patients were unable to return for the followup because of physical infirmity. Two hundred eighteen patients (226 hips) were available for the clinical 5-year followup, and 208 patients (213 hips) were available for the radiographic followup. No intraoperative fracture of the acetabulum occurred; four hips dislocated; 94% clinically were rated as excellent or good. One hip in a patient with rheumatoid arthritis had to be revised for aseptic loosening of the cup and nine femoral stems had to be revised. No migration of the cup could be measured. There was no osteolysis seen around the cup. In six cases a radiolucent line was seen in Zone 1, and in eight hips in Zone 3. There was one hip with a continuous radiolucent line which was considered radiographically loose.

Total hip arthroplasty in neglected congenital dislocation of the hip.

Between 1984 and 1995, 74 total hip replacements were performed in 64 adult patients who had painful untreated congenital dislocation of the hip. The arthroplasty was performed in the position of the true acetabulum in all patients who had either high or low congenital dislocations of the hip. The femoral head was positioned in the true acetabulum after either osteotomy of the greater trochanter or shortening of the femur, or progressively using external fixation. Information was available on all patients with a followup of 1 to 11 years (mean, 7.2 years). Of the 74 replaced hips, 70 showed marked improvement concerning pain, gait, and mobility, according to the Merle D'Aubigne and Postel scale. Four hips were revised with satisfactory results. The reason for revision was infection in one case and loosening of the plastic cup in three cases. Shortening of the femur by removing a segment of bone below the level of the lesser trochanter followed by osteosynthesis without osteotomy of the greater trochanter was found to be the best method for treating bilateral and several unilateral high congenital dislocation of the hip.

Total hip arthroplasty for avascular necrosis and degenerative osteoarthritis of the hip.

Although several studies of various treatment modalities have been reported during the past decade, osteonecrosis of the femoral head remains a difficult therapeutic problem. Total hip replacement which is reserved for patients showing collapse of the femoral head, usually shows poorer results in patients with osteonecrosis compared with those with osteoarthritis. Uncemented total hip arthroplasty was performed on 29 patients with avascular necrosis of the femoral head and 29 patients with degenerative osteoarthritis. After a mean followup of 7.6 years and 7.1 years for the two groups of patients, only one failure was observed in one patient with osteonecrosis. Clinical evaluation after cementless total hip arthroplasty in both groups of patients revealed improvement in all parameters. Postoperatively, pain improved from 1.4 to 5.1, walking ability from 3.4 to 5.3, and range of motion from 4.5 to 5.5 in patients with osteonecrosis, and pain improved from 1.2 to 5.3, walking ability from 3.2 to 5.4, and range of motion from 3.1 to 4.7 in patients with osteoarthritis. Thigh pain was observed postoperatively in only two and three patients treated for osteonecrosis and osteoarthritis, respectively. The present results using cementless arthroplasty seem to be somewhat better than those reported for cemented arthroplasty in patients suffering from osteonecrosis. The clinical and radiographic findings after noncemented arthroplasty in patients with osteonecrosis of the femoral head and in patients with degenerative arthritis of the hip were similar in the two groups.

Stability of proximal femoral grafts in canine hip arthroplasty.

In a canine model, the fixation stability of a prosthesis and proximal bone graft composite were measured relative to the distal femur. One group had the prosthesis graft composite cemented into the distal femur. The second group had the prosthesis graft composite press fit into the distal femur for biologic ingrowth. Displacements of the proximal femoral grafts relative to the host bone in each group were measured after ex vivo (acute with graft) implantation and 4 months after implantation. A third group with no osteotomy (acute intact) simulated perfect graft to host bone union. Relative displacements representing 6 degrees freedom (translation and rotation) were calculated from the displacement values measured by 9 eddy current transducers. Measurements of displacement were used to test the hypothesis that distal press fit fixation equals distal cement fixation at 4 months after implantation. In all cases the measured translations and rotations of the graft to implant construct were small and of a magnitude that should encourage bone ingrowth (< 0.05 mm and < 0.1 degree, respectively). The stability of the press fit group at 4 months was not significantly different from the cemented group in axial and transverse displacement during axial and transverse loading, respectively. There was no difference in stabilities at 4 months between distal press fit and cemented fixation in hip replacements requiring a proximal femoral graft.

Uncemented total arthroplasty in old quiescent infection of the hip.

We reviewed the outcomes of 24 cases (24 patients) of uncemented total hip arthroplasty done to treat secondary osteoarthritis due to quiescent previous infection. There were 16 men and eight women aged from 24 to 78 years (mean, 50 yr). Eight patients had proven or probable tuberculous infection and the other 16 patients had a past history of septic hip. The patients were followed for between 2.5 and 7 years (mean, 4.5 yr). According to the Harris hip rating system, 18 of the patients had excellent or good results. Three patients had a preoperative erythrocyte sedimentation rate of 40 mm/h or higher and had a positive bacterial culture. Two of these patients developed reinfection. The other 21 patients had a preoperative erythrocyte sedimentation rate less than 40 mm/h and no reinfection postoperatively. There were five complications other than infection: dislocation with ipsilateral femoral shaft fracture, intraoperative femoral fracture, cup loosening, periprosthetic osteolysis, and nonunion of the greater trochanter. Uncemented total arthroplasty for old quiescent infection of the hip should be considered if the preoperative erythrocyte sedimentation rate is normal and a course of prophylactic antituberculous therapy is given in patients with an old tuberculous hip.

The influence of patient-related factors and the position of the acetabular component on the rate of dislocation after total hip replacement.

The senior one of us performed 438 primary and 181 revision total hip arthroplasties with use of so-called modern prostheses between July 1983 and January 1994. Fifty-three patients, who had had forty-seven primary procedures and twelve revisions, either died or were lost to follow-up less than two years after the operation and were excluded from the study. The results for the remaining 446 patients (391 primary procedures and 169 revisions) were analyzed to determine the influence of patient-related and operative factors and the position of the acetabular component on the rate of dislocation. Dislocation occurred after thirty-two (6 per cent) of the 560 total hip arthroplasties: seventeen (4 per cent) of the 391 primary procedures and fifteen (9 per cent) of the 169 revisions (p = 0.046). There was no relationship between the variables of age, gender, obesity, or preoperative diagnosis and dislocation after either primary or revision arthroplasty. Seven (23 per cent) of the thirty arthroplasties in the patients who had a history of excessive intake of alcoholic beverages (more than 2.1 liters [seventy-two ounces] of beer or more than 0.2 liter [six ounces] of other alcoholic beverages a day) were followed by a dislocation compared with twenty-five (5 per cent) of the 530 arthroplasties in the patients who did not have such a history. This difference was significant for the patients who had had a revision arthroplasty (p = 0.00005), but with the numbers available we could not detect a difference for those who had had a primary arthroplasty (p = 0.264). Radiographic analysis was performed for thirty-two hips that had dislocated and thirty-two that had not (seventeen primary procedures and fifteen revisions in each group), matched exactly according to the type of prosthesis and the operative approach (but not age). We detected no association between either the version or the abduction angle of the acetabular component (within the range of 39 to 56 degrees for the primary prostheses and 38 to 57 degrees for the revision prostheses) and the risk of dislocation. Thirty of the thirty-two hips in each group had an abduction angle of the acetabular component that was in the so-called safe range of 30 to 50 degrees.

Early radiological observations may predict the long-term survival of femoral hip prostheses.

We reviewed a consecutive series of 527 uninfected hip replacements in patients resident in the UK which had been implanted from 1981 to 1993. All had the same basic design of femoral prosthesis, but four fixation techniques had been used: two press-fit, one HA-coated and one cemented. Review and radiography were planned prospectively. For assessment the components were retrospectively placed into two groups: those which had failed from two years onwards by aseptic femoral loosening and those in which the femoral component had survived without revision or recommendation for revision. All available radiographs in both groups were measured to determine vertical migration and examined by two observers to agree the presence of radiolucent lines (RLLs), lytic lesions, resorption of the neck, proximal osteopenia and distal intramedullary and distal subperiosteal formation of new bone. We then related the presence or absence of these features and the rate of migration at two years to the outcome with regard to aseptic loosening and determined the predictive value of each of these variables. Migration of > or = 2 mm at two years, the presence of an RLL of 2 mm occupying one-third of any one zone, and subperiosteal formation of new bone at the tip of the stem were predictors of aseptic loosening after two years. There were too few lytic lesions to assess at two years, but at five years a lytic lesion > or = 2 mm also predicted failure. We discuss the use of these variables as predictors of femoral aseptic loosening for groups of hips and for individual hips. We conclude that if a group of about 50 total hip replacements, perhaps with a new design of femoral stem, were studied in this way at two years, a mean migration of < 0.4 mm and an incidence of < 10% of RLLs of 2 mm in any one zone would predict 95% survival at ten years. For an individual prosthesis, migration of < 2 mm and the absence of an RLL of < or = 2 mm at two years predict a 6% chance of revision over approximately ten years. If either 2 mm of migration or an RLL of 2 mm is present, the chances of revision rise to 27%, and if both radiological signs are present they are 50%. If at five years a lytic lesion has developed, whatever the situation at two years, there is approximately a 50% chance of failure in the following five years. Our findings suggest that replacements using a limited number of any new design of femoral prosthesis should be screened radiologically at two years before they are generally introduced. We also suggest that radiographs of individual patients at two years and perhaps at five years should be studied to help to decide whether or not the patient should remain under close review or be discharged from specialist follow-up.

Periprosthetic bone remodelling after cementless total hip replacement. A prospective comparison of two different implant designs.

In a prospective study of 14 patients undergoing total hip replacement we have used dual-energy X-ray absorptiometry (DEXA) to investigate remodelling of the bone around two different designs of cementless femoral prosthesis. The bone mineral density (BMD) was measured at 12-weekly intervals for a year. Eight patients (group A) had a stiff, collarless implant and six (group B) a flexible isoelastic implant. Patients in group A showed a decrease in BMD from 14 weeks after operation. By 12 months, the mean loss in BMD was 27%, both medially and laterally to the proximal part of the implant. Those in group B showed an overall increase in BMD which reached a mean of 12.6% on the lateral side of the distal portion of the implant. Our results support the current concepts of the effects of stem stiffness and flexibility on periprosthetic remodelling.