Yukihide Minoda1, Mitsuhiko Ikebuchi2, Akio Kobayashi2,3, Hiroyoshi Iwaki2, Hiroaki Nakamura2. 1. Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi Abeno-ku, Osaka, 545-8585, Japan. yminoda@msic.med.osaka-cu.ac.jp. 2. Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi Abeno-ku, Osaka, 545-8585, Japan. 3. Department of Orthopaedic Surgery, Shiraniwa Hospital, 6-10-1 Shiraniwadai Ikoma, Nara, 630-0136, Japan.
Abstract
PURPOSE: Research has shown that a cemented mobile-bearing component has a favorable effect on the bone mineral density (BMD) of the distal femur at 2 years after total knee arthroplasty (TKA). This study was performed to determine whether the advantage on BMD of a cemented mobile-bearing TKA over a conventional cemented fixed-bearing TKA changes with time. This report is an update of a matched cohort study initiated in 2004 and for which the 2-year results have been published. METHODS: Twenty-eight knees that were treated with a fixed-bearing posterior stabilized (PS) prosthesis and 28 matched knees from a database of 76 knees that were treated with a mobile-bearing PS prosthesis in the same period were investigated. All knees underwent dual-energy X-ray absorptiometry (DEXA) scans around the femoral component preoperatively, 2 weeks postoperatively, 5 years postoperatively, and annually thereafter. Eighteen knees with a cemented mobile-bearing PS prosthesis and 20 knees with a cemented fixed-bearing PS prosthesis were investigated for more than 6 years. The mean follow-up period was 11 years. RESULTS: The range of motion, Knee Society Score, BMD of the lumbar spine, and follow-up period were not significantly different preoperatively and postoperatively in the two groups. In the fixed-bearing group, the BMD of the anterior part of the femoral condyle decreased postoperatively. In the mobile-bearing group, the BMD of the posterior part of the femoral condyle increased postoperatively. The postoperative change in the BMD at 5 years and the latest follow-up period was statistically significant in the two groups. CONCLUSIONS: This DEXA study revealed that a cemented mobile-bearing component had a favorable effect on the BMD of the distal femur after TKA even at a mean of 11 years postoperatively. LEVEL OF EVIDENCE: Therapeutic study, level II, prospective comparative study.
PURPOSE: Research has shown that a cemented mobile-bearing component has a favorable effect on the bone mineral density (BMD) of the distal femur at 2 years after total knee arthroplasty (TKA). This study was performed to determine whether the advantage on BMD of a cemented mobile-bearing TKA over a conventional cemented fixed-bearing TKA changes with time. This report is an update of a matched cohort study initiated in 2004 and for which the 2-year results have been published. METHODS: Twenty-eight knees that were treated with a fixed-bearing posterior stabilized (PS) prosthesis and 28 matched knees from a database of 76 knees that were treated with a mobile-bearing PS prosthesis in the same period were investigated. All knees underwent dual-energy X-ray absorptiometry (DEXA) scans around the femoral component preoperatively, 2 weeks postoperatively, 5 years postoperatively, and annually thereafter. Eighteen knees with a cemented mobile-bearing PS prosthesis and 20 knees with a cemented fixed-bearing PS prosthesis were investigated for more than 6 years. The mean follow-up period was 11 years. RESULTS: The range of motion, Knee Society Score, BMD of the lumbar spine, and follow-up period were not significantly different preoperatively and postoperatively in the two groups. In the fixed-bearing group, the BMD of the anterior part of the femoral condyle decreased postoperatively. In the mobile-bearing group, the BMD of the posterior part of the femoral condyle increased postoperatively. The postoperative change in the BMD at 5 years and the latest follow-up period was statistically significant in the two groups. CONCLUSIONS: This DEXA study revealed that a cemented mobile-bearing component had a favorable effect on the BMD of the distal femur after TKA even at a mean of 11 years postoperatively. LEVEL OF EVIDENCE: Therapeutic study, level II, prospective comparative study.
Keywords:
Bone mineral density; Fixed-bearing total knee prosthesis; Mobile-bearing total knee prosthesis; Posterior stabilized total knee prosthesis; Total knee arthroplasty
Authors: Michael T Hirschmann; Farhad Iranpour; Praveen Konala; Anna Kerner; Helmut Rasch; Justin P Cobb; Niklaus F Friederich Journal: Knee Surg Sports Traumatol Arthrosc Date: 2010-02-11 Impact factor: 4.342
Authors: Andreas M Murer; Michael T Hirschmann; Felix Amsler; Helmut Rasch; Rolf W Huegli Journal: Knee Surg Sports Traumatol Arthrosc Date: 2019-07-01 Impact factor: 4.342