Marc R Angerame1, Catie L Eschen2, Roseann M Johnson2, Jason M Jennings3, Douglas A Dennis4. 1. Illinois Bone & Joint Research and Education Institute, Des Plaines, IL. 2. Colorado Joint Replacement, Porter Adventist Hospital, Denver, CO. 3. Colorado Joint Replacement, Porter Adventist Hospital, Denver, CO; Department of Mechanical and Materials Engineering, University of Denver, Denver, CO. 4. Colorado Joint Replacement, Porter Adventist Hospital, Denver, CO; Department of Mechanical and Materials Engineering, University of Denver, Denver, CO; Department of Orthopaedics, University of Colorado School of Medicine, Denver, CO; Department of Biomedical Engineering, University of Tennessee, Knoxville, TN.
Abstract
BACKGROUND: High-flexion total knee arthroplasty (HF-TKA) prostheses were designed with hopes of improving knee function. Studies have suggested increased failure with HF-TKAs. The purpose is to compare clinical results of HF-TKA versus conventional TKA (C-TKA) from the same implant system with long-term follow-up. METHODS: This review of prostheses implanted between 2004 and 2007 matched 145 of 179 possible HF-TKAs with 145 of 1347 possible C-TKAs. Mean follow-up was 121.5 ± 20.3 months. We were unable to match 12 HF-TKAs. HF-TKAs with less than 8-year follow-up were excluded. The primary outcome was failure requiring revision. Secondary outcomes included range of motion (ROM), Knee Society Scores (KSS), and radiolucent lines. RESULTS: In the matched cohort, there were 15 HF-TKA reoperations, 8 of which involved component revisions. There were 12 reoperations in the C-TKA cohort but no component revisions (P = .001). The analysis of the unmatched cohorts revealed a higher revision rate for HF-TKAs (P = .039) (HF-TKA: 10/179 vs C-TKA: 27/1347). At final follow-up, HF-TKAs exhibited more prosthesis radiolucent lines without evidence of loosening. Particularly, HF-TKAs demonstrated more femoral zone IV radiolucencies (38.7%) at final follow-up compared with C-TKAs (13.8%) (P < .001). There were no differences found between cohorts in ROM or KSS. CONCLUSION: This study found an increased incidence of failure requiring revision with the HF-TKA in the matched and unmatched analyses. Higher incidences of radiolucent lines were found with HF-TKA. With no observed differences in ROM or KSS and a higher rate of failure with HF-TKA, there appears to be no advantage for use of the HF-TKA.
BACKGROUND: High-flexion total knee arthroplasty (HF-TKA) prostheses were designed with hopes of improving knee function. Studies have suggested increased failure with HF-TKAs. The purpose is to compare clinical results of HF-TKA versus conventional TKA (C-TKA) from the same implant system with long-term follow-up. METHODS: This review of prostheses implanted between 2004 and 2007 matched 145 of 179 possible HF-TKAs with 145 of 1347 possible C-TKAs. Mean follow-up was 121.5 ± 20.3 months. We were unable to match 12 HF-TKAs. HF-TKAs with less than 8-year follow-up were excluded. The primary outcome was failure requiring revision. Secondary outcomes included range of motion (ROM), Knee Society Scores (KSS), and radiolucent lines. RESULTS: In the matched cohort, there were 15 HF-TKA reoperations, 8 of which involved component revisions. There were 12 reoperations in the C-TKA cohort but no component revisions (P = .001). The analysis of the unmatched cohorts revealed a higher revision rate for HF-TKAs (P = .039) (HF-TKA: 10/179 vs C-TKA: 27/1347). At final follow-up, HF-TKAs exhibited more prosthesis radiolucent lines without evidence of loosening. Particularly, HF-TKAs demonstrated more femoral zone IV radiolucencies (38.7%) at final follow-up compared with C-TKAs (13.8%) (P < .001). There were no differences found between cohorts in ROM or KSS. CONCLUSION: This study found an increased incidence of failure requiring revision with the HF-TKA in the matched and unmatched analyses. Higher incidences of radiolucent lines were found with HF-TKA. With no observed differences in ROM or KSS and a higher rate of failure with HF-TKA, there appears to be no advantage for use of the HF-TKA.