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Acetabular reconstruction with porous components in dysplastic hips using a modified Hess protrusio socket technique
Abstracts from the AAHKS Seventh Annual Meeting Our study suggested that despite concerns regarding weaker bone quality and the existence of comorbidities such as osteoporosis or other metabolic disorders, uncemented acetabular components functioned well in an elderly population, producing results that were comparable to those seen in a younger comparison group. In fact, there was a lower incidence of both radiolucent lines and polyethylene wear in the elderly group when compared to the younger population, which could have been attributed to decreased mechanic demands on the components. We conclude that advanced age at the time of index surgery does not appear to be a contraindication for the use of uncemented aeetabular components.
PAPER # 10 *ACETABULAR RECONSTRUCTION WITH POROUS COMPONENTS IN DYSPLASTIC HIPS U S I N G A MODIFIED HESS PROTRUSIO SOCKET TECHNIQUE Samer N. Tawakkol, MD, Los Angeles, CA, William Long, MD, Lawrence Dorr, MD Introduction: Total hip replacement in patients with DDH is a challenging and complex operation. The purpose of this study is that cementless acetabular fixation with a modified Hess protrusio technique provides predictable and durable fixation. Materials and Methods: Twenty-nine patients with 36 dysplastic hips were operated with THR by one surgeon. Hemispherical porous coated noncemented acetabular components were used in 32 hips. Patients were followed for an average 6.3 years (five years - 12.5 years). The first eight of these hips were operated with a technique which preserved the medial wall and used a bone graft as necessary to cover superior and lateral defects. In 22 hips protrusio technique was performed to permit creation of a hemispheric acetabular cavity which provided a stable press fit of the acetabular component without the necessity of bone graft. The mean age at the time of the index operation was 45 years (range 22 to 69 years). The Ranawat triangle, femoral head subluxation by the Crowe classification and the medial wall thickness from Kohler's line were measured preoperatively. The acetabular component in relationship to Ranawat's triangle and protrusio beyond Kohler's line, theta angle, and coverage of the bone graft was measured postop. Results: The acetabular revision rate for the study was 6.2 percent at average 6.3 years. Twelve hips were classified as Crowe Grade I, eight as Grade II, eight as Grade III, and eight as Grade IV. With this technique the average mediallzation of the cup beyond Kohler's line was 1 m m for Crowe I and II, 2.6 m m for Crowe HI and 1 m m for Crowe IV. Crowe IV deformities are always reconstructed at the true acetabulum. The bony coverage of the cup laterally was more than 90% in all 24 hips. The femoral head autograft covered less than 30% of the cup in all eight hips. Twenty-two hips were implanted with the protrusio technique and none of these hips have been revised or were loose or had migrated. Discussion: This study demonstrates that acetabular reconstruction in patients with hip dysplasia can be accomplished using cementless fixation. None of the non-cemented cups implanted with the protrusio technique have been revised. The absence of revision is not a superior revision rate when compared to cemented Charnley components at the same time postoperatively. However, cemented Charnley components at the same time do have a higher radiographic loosening rate. Predictable fixation can be obtained with the protmsio technique which does provide the principles of implantation for a hemispherical porous coated acetabular component. This study confirms that bone graft coverage of 30% or less provide a stable construct.
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PAPER # 11 *CEMENTLESS ACETABULAR REVISION ARTHROPLASTY WITH A POROUS, TITANIUM, MODULAR HEMISPHERICAL COMPONENT Christopher W. Olcott, MD, Rochester, NY, David A. Mattingly, ME), Benjamin E. Bierbanm, ME) Although a fixed, porous-coated, hemispherical acetabular component has become the standard in most revision situations, intermediate and longterm results of such components are limite& The purpose of this study was to assess the efficacy of a cementless acetabular component in revision hip arthroplasty at a range of four-to-ten years. Between December 1987 and March 1992,150 consecutive acetabular revisions were performed by two surgeons. In each case, a hemispherical titanium acetabular shell coated with titanium beads was implanted with or without supplemental dome screw fixation. At a mean follow-up of 6.3 years (range 4 - 10 years), 119 acetabular revisions were available for clinical and radiographic review. Fifty-six of the 119 hips had simultaneous femoral revisions. Each patient was either interviewed or answered a questionnaire for determination of a Harris hip score. Immediate postoperative radiographs were compared to most recent follow-up films for bony fixation, migration, wear and osteolysis. The average postoperative Harris hip score improved to eighty-one from forty-two preoperatively. Twenty-six hips (21.8%) h a v e u n d e r g o n e reoperations: eight (6.7%) for instability, seven (5.9%) for femoral revision, four (3.4%) for reexploration (debridement heterotopic ossification / removal of hardware), two (1.7%) for infection, one (0.8%) for early postoperative migration at three weeks and four (3.4%) for aseptic loosening. Although a variety of femoral components were used in conjunction with this acetabular shell, those with osteolysis and those requiring revision were noted. Seven femoral stems (5.9%) were re'~'ised and another twenty-five demonstrated some degree of osteolysis confined primarily to the proximal zones. Acetabular osteolysis evident in eleven hips was not extensive enough to warrant re-revision. Acetabular liner exchange was performed in the seven hips requiring femoral revision and three hips with instability. Radiographic evidence of acetabular migration was noted in seven hips (6.5%); six of which were associated with a bulk, structural allograft. The results of this cementless, titanium, hemispherical acetabular component outperform those of cemented cups at similar follow-up and compare favorably with other cementless designs. A good clinical and radiographic outcome support its continued use in acetabular revision surgery.
PAPER # 12 PELVIC DISCONTINUITY IN ACETABULAR REVISION SURGERY Daniel J. Berry, MD, Rochester,MN, Arlen D. Hanssen, MD, David G. Lewallen, MD, Miguel E. Cabanela, MD Introduction: Pelvic discontinuity (AAOS Type W bone deficiency, defined as discontinuity between the ihum superiorly and the pubis and ischeum inferiorly) is an uncommon but extremely difficult problem encountered during acetabular revision surgery. No series of more than a few patients has been reported to date. The purpose of this study was to characterize patients at risk for pelvic discontinuity and report the results of treatment of this problem. Materials and Methods: All cases of pelvic discontinuity identified during revision THA at one institution were reviewed. Pelvic discontinuity was classified as Type IVa (3 hips) if it occurred in the absence of severe segmental or combined pelvic bone loss, Type IVb (21 hips) if it occurred in the presence of segmental or combined pelvic bone loss and Type Wc (5 hips) if after previous pelvic irradiation.
* Denotes that something of value was received Presenters are boldface
Treatment for the discontinuity was plating of both columns in 5, plating of one column in 7, stabilization with a Burch-Schneider anti-pmtrusio cage in 13, stabilization with the implant alone in 2 and girdlestone procedure in 2. Nine had bulk structural grafts. All revised patients had particulate allograft and 11 also had autograft at discontinuity site.
PAPER # 10 *ACETABULAR RECONSTRUCTION WITH POROUS COMPONENTS IN DYSPLASTIC HIPS U S I N G A MODIFIED HESS PROTRUSIO SOCKET TECHNIQUE Samer N. Tawakkol, MD, Los Angeles, CA, William Long, MD, Lawrence Dorr, MD Introduction: Total hip replacement in patients with DDH is a challenging and complex operation. The purpose of this study is that cementless acetabular fixation with a modified Hess protrusio technique provides predictable and durable fixation. Materials and Methods: Twenty-nine patients with 36 dysplastic hips were operated with THR by one surgeon. Hemispherical porous coated noncemented acetabular components were used in 32 hips. Patients were followed for an average 6.3 years (five years - 12.5 years). The first eight of these hips were operated with a technique which preserved the medial wall and used a bone graft as necessary to cover superior and lateral defects. In 22 hips protrusio technique was performed to permit creation of a hemispheric acetabular cavity which provided a stable press fit of the acetabular component without the necessity of bone graft. The mean age at the time of the index operation was 45 years (range 22 to 69 years). The Ranawat triangle, femoral head subluxation by the Crowe classification and the medial wall thickness from Kohler's line were measured preoperatively. The acetabular component in relationship to Ranawat's triangle and protrusio beyond Kohler's line, theta angle, and coverage of the bone graft was measured postop. Results: The acetabular revision rate for the study was 6.2 percent at average 6.3 years. Twelve hips were classified as Crowe Grade I, eight as Grade II, eight as Grade III, and eight as Grade IV. With this technique the average mediallzation of the cup beyond Kohler's line was 1 m m for Crowe I and II, 2.6 m m for Crowe HI and 1 m m for Crowe IV. Crowe IV deformities are always reconstructed at the true acetabulum. The bony coverage of the cup laterally was more than 90% in all 24 hips. The femoral head autograft covered less than 30% of the cup in all eight hips. Twenty-two hips were implanted with the protrusio technique and none of these hips have been revised or were loose or had migrated. Discussion: This study demonstrates that acetabular reconstruction in patients with hip dysplasia can be accomplished using cementless fixation. None of the non-cemented cups implanted with the protrusio technique have been revised. The absence of revision is not a superior revision rate when compared to cemented Charnley components at the same time postoperatively. However, cemented Charnley components at the same time do have a higher radiographic loosening rate. Predictable fixation can be obtained with the protmsio technique which does provide the principles of implantation for a hemispherical porous coated acetabular component. This study confirms that bone graft coverage of 30% or less provide a stable construct.
225
PAPER # 11 *CEMENTLESS ACETABULAR REVISION ARTHROPLASTY WITH A POROUS, TITANIUM, MODULAR HEMISPHERICAL COMPONENT Christopher W. Olcott, MD, Rochester, NY, David A. Mattingly, ME), Benjamin E. Bierbanm, ME) Although a fixed, porous-coated, hemispherical acetabular component has become the standard in most revision situations, intermediate and longterm results of such components are limite& The purpose of this study was to assess the efficacy of a cementless acetabular component in revision hip arthroplasty at a range of four-to-ten years. Between December 1987 and March 1992,150 consecutive acetabular revisions were performed by two surgeons. In each case, a hemispherical titanium acetabular shell coated with titanium beads was implanted with or without supplemental dome screw fixation. At a mean follow-up of 6.3 years (range 4 - 10 years), 119 acetabular revisions were available for clinical and radiographic review. Fifty-six of the 119 hips had simultaneous femoral revisions. Each patient was either interviewed or answered a questionnaire for determination of a Harris hip score. Immediate postoperative radiographs were compared to most recent follow-up films for bony fixation, migration, wear and osteolysis. The average postoperative Harris hip score improved to eighty-one from forty-two preoperatively. Twenty-six hips (21.8%) h a v e u n d e r g o n e reoperations: eight (6.7%) for instability, seven (5.9%) for femoral revision, four (3.4%) for reexploration (debridement heterotopic ossification / removal of hardware), two (1.7%) for infection, one (0.8%) for early postoperative migration at three weeks and four (3.4%) for aseptic loosening. Although a variety of femoral components were used in conjunction with this acetabular shell, those with osteolysis and those requiring revision were noted. Seven femoral stems (5.9%) were re'~'ised and another twenty-five demonstrated some degree of osteolysis confined primarily to the proximal zones. Acetabular osteolysis evident in eleven hips was not extensive enough to warrant re-revision. Acetabular liner exchange was performed in the seven hips requiring femoral revision and three hips with instability. Radiographic evidence of acetabular migration was noted in seven hips (6.5%); six of which were associated with a bulk, structural allograft. The results of this cementless, titanium, hemispherical acetabular component outperform those of cemented cups at similar follow-up and compare favorably with other cementless designs. A good clinical and radiographic outcome support its continued use in acetabular revision surgery.
PAPER # 12 PELVIC DISCONTINUITY IN ACETABULAR REVISION SURGERY Daniel J. Berry, MD, Rochester,MN, Arlen D. Hanssen, MD, David G. Lewallen, MD, Miguel E. Cabanela, MD Introduction: Pelvic discontinuity (AAOS Type W bone deficiency, defined as discontinuity between the ihum superiorly and the pubis and ischeum inferiorly) is an uncommon but extremely difficult problem encountered during acetabular revision surgery. No series of more than a few patients has been reported to date. The purpose of this study was to characterize patients at risk for pelvic discontinuity and report the results of treatment of this problem. Materials and Methods: All cases of pelvic discontinuity identified during revision THA at one institution were reviewed. Pelvic discontinuity was classified as Type IVa (3 hips) if it occurred in the absence of severe segmental or combined pelvic bone loss, Type IVb (21 hips) if it occurred in the presence of segmental or combined pelvic bone loss and Type Wc (5 hips) if after previous pelvic irradiation.
* Denotes that something of value was received Presenters are boldface
Treatment for the discontinuity was plating of both columns in 5, plating of one column in 7, stabilization with a Burch-Schneider anti-pmtrusio cage in 13, stabilization with the implant alone in 2 and girdlestone procedure in 2. Nine had bulk structural grafts. All revised patients had particulate allograft and 11 also had autograft at discontinuity site.