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Tibial component failure mechanisms in total knee replacement
262 The Journal of Arthroplasty Vol. 19 No. 2 February 2004 Methods: This study reports the midterm clinical and radiographic result of 50 patients with FAI who were treated with surgical dislocation of the hip between 1996 and 2000 at our institution. There were 39 males and 11 females with a mean age of 36 years (range, 21 to 52 years). The follow-up averaged 4.7 years (4 to 5.2 years).
recommended. The senior author had always espoused placing the acetabular component as inferior and medial as possible, and was willing to leave cementless acetabular components up to 30% uncovered. The purpose of this study was to evaluate cementless acetabular fixation in cases of CDH, at a minimum ten-year follow-up.
Results: The Merle d’Aubigne´ hip score improved from 14.1 points preoperatively to 16.5 points, with 38 hips rated as excellent to good at the latest follow-up. There was no avascular necrosis of the femoral head. At the latest follow-up, 5 out of the 50 hips, all with evidence of severe initial chondral lesions, have undergone subsequent total hip arthroplasty.
Methods: Between 1986 and 1992, the senior author performed 22 non-selective consecutive THRs in 18 patients with CDH. All patients received a cementless acetabular component and a cemented femoral component. No acetabular components were utilized. Crowe types were I in 50%, II in 15%, II in 10%, and IV in 25%. Data was prospectively collected. Hips were evaluated for percent of acetabular uncoverage, need for revision, revision, radiolucent lines, component position change, wear and osteolysis.
Discussion and Conclusions: This study concludes that surgical dislocation of the hip, with recognition and protection of the critical blood supply to the femoral head, can be carried out with relative safety, and is expected to have a favorable result for patients with early FAI. The outcome of surgical intervention is suboptimal for patients with extensive and full thickness chondral lesions.
Results: At minimum 10 year follow-up, 13 patients were living and 5 patients were deceased. The average radiographic follow-up was 13 years (range 7 to 16 years). Acetabular component uncoverage averaged 15%, range 0 to 33%. One acetabular component was revised for osteolysis and another liner was exchanged for excessive wear. No hip demonstrated circumferential acetabular radiolucencies or migration. Two femoral components had subsided, but were not revised. Conclusion: The technique of inferior medial cementless acetabular component placement without the use of bone grafting provided durable results at a minimum 10-year follow-up, with no shells revised for loosening.
POSTER #9 PATELLAR RESURFACING DURING TOTAL KNEE ARTHROPLASTY: A METAANALYSIS Venkat Rapuri, MD, Javad Parvizi, MD, Khaled Saleh, MD, Peter Sharkey, MD, William Hozack, MD, Michael Mont, MD Introduction: The need for patellar resurfacing during total knee arthroplasty remains a controversial issue. A vast number of conflicting reports have been published in the literature. The objective of this meta-analysis was to evaluate the role of patellar resurfacing. Methods: A computerized literature search was conducted to identify all citations, between 1966 to 2003, concerning patellar resurfacing or retention during total knee arthroplasty. All the Englishlanguage abstracts were obtained. A multistage assessment was then used to identify articles fulfilling the inclusion criteria for the study. All randomized, prospective studies reporting the result of total knee arthroplasty using modern condylar design prosthesis with and without patellar resurfacing were included. Details of any reported data were extracted and extensive analysis of relevant variables carried out.
POSTER #12 NUANCES OF NAVIGATION: THE LEARNING CURVE IN TOTAL KNEE REPLACEMENT David R. Lionberger, MD, Philip Noble, PhD, Michael Conditt, PhD, Matthew Thompson, MS, Bryan Ding, BS
Results: 158 published articles pertaining to patellar resurfacing were identified of which 22 studies were potentially eligible. 15 articles met all inclusion and exclusion criteria. This comprised 1,496 knees of which the patella was resurfaced in 48.6%. 8 of the 15 studies comprising of 1,096 knees favored patellar resurfacing. The remaining studies (400 knees) did not detect a significant benefit for resurfacing of the patella. Knees with patellar resurfacing had lower incidence of anterior knee pain (p⬍0.001) and higher cumulative functional scores (p⬍0.005). The incidence of reoperation and revision for patellofemoral problems was the same in both groups.
Introduction: Surgically navigated patients were studied to assess accuracy, opiate consumption, range of motion, and hospital stay.
Discussions and Conclusion: Patellar resurfacing using a modern condylar design of knee prosthesis is likely to reduce the incidence of anterior knee pain without increasing complications related to patellofemoral joint.
Results: Use of the navigation system increased operative times by an average of 40%. Morphine administration during hospitalization was significantly less in the navigated patients compared to non-navigated controls. At two months post-op, there was no significant difference in knee extension or range of motion of the two groups.
Methods: Thirty knees were evaluated over the first six months of use of a surgical navigation system (Leibinger). Radiographs were used to assess accuracy of AP and lateral alignment and position in addition to evaluation of range of motion, joint laxity, time until weight bearing, and return to full function.
Conclusion: Navigation may potentially improve accuracy in terms of alignment and component position. However, for surgical navigation to be a more useful tool, the cost and the operative time of CAOS must be reduced.
POSTER #10 TIBIAL COMPONENT FAILURE MECHANISMS IN TOTAL KNEE REPLACEMENT Michael E. Berend, MD, Merrill A. Ritter, MD, E. Michael Keating, MD, Philip M. Faris, MD, John B. Meding, MD Introduction: The purpose of this study was to evaluate the mechanisms of AGC tibial failure. Methods: 3152 TKR performed for OA with 2-year follow-up were analyzed.
POSTER #13
Results: 41 tibial components were revised (1.3%) for the following mechanisms: medial tibial collapse (n⫽20), ligamentous imbalance (n⫽13), radiolucencies (n⫽6), pain (n⫽2). Regression tree analysis determined medial collapse was associated with tibial component alignment ⬎ 3.9° of varus, BMI ⬎ 33.7, and varus limb alignment. Posterolateral ligamentous imbalance was more prevalent in knees with preoperative valgus deformity.
IN VIVO COMPARISON OF TRADITIONAL VS. HIGHLY CROSSLINKED POLYETHYLENE WEAR David Manning, MD, Peter Chiang, John Martell, MD, William H. Harris, MD, DSc
Conclusion: Varus limb and component alignment and increased BMI were associated with medial tibial collapse. Valgus knees may be at risk for posterolateral imbalance. The dominant failure mechanisms of this knee design are related to component alignment and ligamentous balance and not polyethylene wear.
Introduction: Highly crosslinked polyethylene is an alternate bearing material designed to improve wear performance and reduce particle disease. Hip simulator data demonstrates that warm irradiated annealed (WIAM) polyethylene has improved wear compared to traditional polyethylene. The aim of this study was to compare the in vivo wear performance of WIAM highly crosslinked polyethylene and traditional UHMWPE. We hypothesize that in vivo wear rate of WIAM highly crosslinked polyethylene is greatly reduced compared to traditional polyethylene.
POSTER #11 CEMENTLESS ACETABULAR FIXATION IN THR PERFORMED FOR CDH: IS BONE GRAFTING NECESSARY? John J. Callaghan, MD, Brian Schroeder, Jose A. Morcuende, MD, Devon D. Goetz, MD, Patrick M. Sullivan, MD, Douglas R. Pedersen, PhD, Richard C. Johnston, MD Background: Initially, in the cases of CDH requiring total hip arthroplasty, cement with superolateral bone grafting was advocated and later, cementless acetabular components with bone grafting were
Methods: 109 hips with WIAM polyethylene and follow up duration of up to 44 months had 243 acceptable radiograph pairs for wear analysis. An age matched population of patients with traditional polyethylene and 4 year follow up served as a control group. Two dimensional vector wear analysis was performed on each series using the Martell system, which has been shown to determine 90 percent of 3 dimensional femoral head penetration. Steady state and overall wear rates for WIAM highly crosslinked and traditional polyethylene were compared. ANOVA was performed to assess the effect of traditional wear variables (head size, gender, activity level, and BMI). Results: WIAM polyethylene steady state wear rate was 11 micra/year vs. 143 micra/year with traditional polyethylene. WIAM polyethylene penetration rate was not effected by traditional wear factors (head size, gender, age, activity level, or BMI). Conclusions: In this in vivo comparative wear rate study, WIAM highly crosslinked polyethylene steady state wear was 92 percent less than similarly determined steady state wear in traditional polyethylene. Traditional wear factors appeared to make no difference.
recommended. The senior author had always espoused placing the acetabular component as inferior and medial as possible, and was willing to leave cementless acetabular components up to 30% uncovered. The purpose of this study was to evaluate cementless acetabular fixation in cases of CDH, at a minimum ten-year follow-up.
Results: The Merle d’Aubigne´ hip score improved from 14.1 points preoperatively to 16.5 points, with 38 hips rated as excellent to good at the latest follow-up. There was no avascular necrosis of the femoral head. At the latest follow-up, 5 out of the 50 hips, all with evidence of severe initial chondral lesions, have undergone subsequent total hip arthroplasty.
Methods: Between 1986 and 1992, the senior author performed 22 non-selective consecutive THRs in 18 patients with CDH. All patients received a cementless acetabular component and a cemented femoral component. No acetabular components were utilized. Crowe types were I in 50%, II in 15%, II in 10%, and IV in 25%. Data was prospectively collected. Hips were evaluated for percent of acetabular uncoverage, need for revision, revision, radiolucent lines, component position change, wear and osteolysis.
Discussion and Conclusions: This study concludes that surgical dislocation of the hip, with recognition and protection of the critical blood supply to the femoral head, can be carried out with relative safety, and is expected to have a favorable result for patients with early FAI. The outcome of surgical intervention is suboptimal for patients with extensive and full thickness chondral lesions.
Results: At minimum 10 year follow-up, 13 patients were living and 5 patients were deceased. The average radiographic follow-up was 13 years (range 7 to 16 years). Acetabular component uncoverage averaged 15%, range 0 to 33%. One acetabular component was revised for osteolysis and another liner was exchanged for excessive wear. No hip demonstrated circumferential acetabular radiolucencies or migration. Two femoral components had subsided, but were not revised. Conclusion: The technique of inferior medial cementless acetabular component placement without the use of bone grafting provided durable results at a minimum 10-year follow-up, with no shells revised for loosening.
POSTER #9 PATELLAR RESURFACING DURING TOTAL KNEE ARTHROPLASTY: A METAANALYSIS Venkat Rapuri, MD, Javad Parvizi, MD, Khaled Saleh, MD, Peter Sharkey, MD, William Hozack, MD, Michael Mont, MD Introduction: The need for patellar resurfacing during total knee arthroplasty remains a controversial issue. A vast number of conflicting reports have been published in the literature. The objective of this meta-analysis was to evaluate the role of patellar resurfacing. Methods: A computerized literature search was conducted to identify all citations, between 1966 to 2003, concerning patellar resurfacing or retention during total knee arthroplasty. All the Englishlanguage abstracts were obtained. A multistage assessment was then used to identify articles fulfilling the inclusion criteria for the study. All randomized, prospective studies reporting the result of total knee arthroplasty using modern condylar design prosthesis with and without patellar resurfacing were included. Details of any reported data were extracted and extensive analysis of relevant variables carried out.
POSTER #12 NUANCES OF NAVIGATION: THE LEARNING CURVE IN TOTAL KNEE REPLACEMENT David R. Lionberger, MD, Philip Noble, PhD, Michael Conditt, PhD, Matthew Thompson, MS, Bryan Ding, BS
Results: 158 published articles pertaining to patellar resurfacing were identified of which 22 studies were potentially eligible. 15 articles met all inclusion and exclusion criteria. This comprised 1,496 knees of which the patella was resurfaced in 48.6%. 8 of the 15 studies comprising of 1,096 knees favored patellar resurfacing. The remaining studies (400 knees) did not detect a significant benefit for resurfacing of the patella. Knees with patellar resurfacing had lower incidence of anterior knee pain (p⬍0.001) and higher cumulative functional scores (p⬍0.005). The incidence of reoperation and revision for patellofemoral problems was the same in both groups.
Introduction: Surgically navigated patients were studied to assess accuracy, opiate consumption, range of motion, and hospital stay.
Discussions and Conclusion: Patellar resurfacing using a modern condylar design of knee prosthesis is likely to reduce the incidence of anterior knee pain without increasing complications related to patellofemoral joint.
Results: Use of the navigation system increased operative times by an average of 40%. Morphine administration during hospitalization was significantly less in the navigated patients compared to non-navigated controls. At two months post-op, there was no significant difference in knee extension or range of motion of the two groups.
Methods: Thirty knees were evaluated over the first six months of use of a surgical navigation system (Leibinger). Radiographs were used to assess accuracy of AP and lateral alignment and position in addition to evaluation of range of motion, joint laxity, time until weight bearing, and return to full function.
Conclusion: Navigation may potentially improve accuracy in terms of alignment and component position. However, for surgical navigation to be a more useful tool, the cost and the operative time of CAOS must be reduced.
POSTER #10 TIBIAL COMPONENT FAILURE MECHANISMS IN TOTAL KNEE REPLACEMENT Michael E. Berend, MD, Merrill A. Ritter, MD, E. Michael Keating, MD, Philip M. Faris, MD, John B. Meding, MD Introduction: The purpose of this study was to evaluate the mechanisms of AGC tibial failure. Methods: 3152 TKR performed for OA with 2-year follow-up were analyzed.
POSTER #13
Results: 41 tibial components were revised (1.3%) for the following mechanisms: medial tibial collapse (n⫽20), ligamentous imbalance (n⫽13), radiolucencies (n⫽6), pain (n⫽2). Regression tree analysis determined medial collapse was associated with tibial component alignment ⬎ 3.9° of varus, BMI ⬎ 33.7, and varus limb alignment. Posterolateral ligamentous imbalance was more prevalent in knees with preoperative valgus deformity.
IN VIVO COMPARISON OF TRADITIONAL VS. HIGHLY CROSSLINKED POLYETHYLENE WEAR David Manning, MD, Peter Chiang, John Martell, MD, William H. Harris, MD, DSc
Conclusion: Varus limb and component alignment and increased BMI were associated with medial tibial collapse. Valgus knees may be at risk for posterolateral imbalance. The dominant failure mechanisms of this knee design are related to component alignment and ligamentous balance and not polyethylene wear.
Introduction: Highly crosslinked polyethylene is an alternate bearing material designed to improve wear performance and reduce particle disease. Hip simulator data demonstrates that warm irradiated annealed (WIAM) polyethylene has improved wear compared to traditional polyethylene. The aim of this study was to compare the in vivo wear performance of WIAM highly crosslinked polyethylene and traditional UHMWPE. We hypothesize that in vivo wear rate of WIAM highly crosslinked polyethylene is greatly reduced compared to traditional polyethylene.
POSTER #11 CEMENTLESS ACETABULAR FIXATION IN THR PERFORMED FOR CDH: IS BONE GRAFTING NECESSARY? John J. Callaghan, MD, Brian Schroeder, Jose A. Morcuende, MD, Devon D. Goetz, MD, Patrick M. Sullivan, MD, Douglas R. Pedersen, PhD, Richard C. Johnston, MD Background: Initially, in the cases of CDH requiring total hip arthroplasty, cement with superolateral bone grafting was advocated and later, cementless acetabular components with bone grafting were
Methods: 109 hips with WIAM polyethylene and follow up duration of up to 44 months had 243 acceptable radiograph pairs for wear analysis. An age matched population of patients with traditional polyethylene and 4 year follow up served as a control group. Two dimensional vector wear analysis was performed on each series using the Martell system, which has been shown to determine 90 percent of 3 dimensional femoral head penetration. Steady state and overall wear rates for WIAM highly crosslinked and traditional polyethylene were compared. ANOVA was performed to assess the effect of traditional wear variables (head size, gender, activity level, and BMI). Results: WIAM polyethylene steady state wear rate was 11 micra/year vs. 143 micra/year with traditional polyethylene. WIAM polyethylene penetration rate was not effected by traditional wear factors (head size, gender, age, activity level, or BMI). Conclusions: In this in vivo comparative wear rate study, WIAM highly crosslinked polyethylene steady state wear was 92 percent less than similarly determined steady state wear in traditional polyethylene. Traditional wear factors appeared to make no difference.