Background: Sagittal plane placement of the tibial component in total knee replacement (TKR) has important implications for maximizing the range of flexion motion, allowing collateral ligaments to function more normal...Background: Sagittal plane placement of the tibial component in total knee replacement (TKR) has important implications for maximizing the range of flexion motion, allowing collateral ligaments to function more normally, as well as providing ideal compressive loading on the tibial bone-prosthesis interface. This study attempts to quantify the normal posterior tibial slope (PTS) angle pre-operatively and post-operatively in osteoarthritic patients after using a conventional extramedullary tibial resection guide to assess its effectiveness. Methods: Forty-nine primary cementless total knee replacements in 34 osteoarthritic patients were measured radiographically pre-operatively and one year post-operatively to determine the PTS and its effect on range of motion. Lateral X-rays, using the anterior cortical line of the tibia, were employed for all measurements. Results: Pre-operative PTS measured 11.83˚ (range 5˚ - 18˚), while post-operative PTS of implanted tibial components measured 11.30o (range 4˚ - 18˚). The pre-operative range of motion of 112˚ (range 30˚ to 135˚) was improved to 119˚ (range 90˚ to 135˚) post-operatively after 1 year. Conclusions: Anterior tibial shaft referencing using a conventional extramedullary tibial resection guide provides an easy and convenient method for reproducing the anatomical PTS during TKR. This methodology provided improvement in average range of motion from 112˚ pre-operatively to 119˚ post-operatively at one year.展开更多
Background: Resurfacing-type total hip replacement (THR) has been successfully developed over the past 50 years through collaborative efforts between engineers and surgeons. Much of the development was pursued by indi...Background: Resurfacing-type total hip replacement (THR) has been successfully developed over the past 50 years through collaborative efforts between engineers and surgeons. Much of the development was pursued by individuals or groups, each of which participated in adding further refinements to the implants, instruments and surgical procedures, thus minimizing the serious problems of wear, osteolysis, loosening and femoral neck fractures. The purpose of this study is to explore the development process to optimize the resurfacing total hip replacement into its current application. Methods: In the early 1980s, cementless resurfacing implants were developed using “thin shell” technology to minimize bony resection of the acetabulum and femoral head. Femoral components utilized short, non-porous coated, tapered straight stems to reduce shear stresses in the femoral neck to prevent fractures and stress shielding, while mechanically stabilizing and aligning the components. Acetabular components were anatomically designed to be recessed inside bony borders to avoid neck-cup impingement and loosening. Initially, ultrahigh molecular weight polyethylene (UHMWPE) was used as a bearing, but due to high levels of wear and osteolysis, it was replaced by wear-resistant highly crossed-linked polyethylene (HXLPE) in 2008. Results: Use of HXLPE as a bearing material in both Co-Cr-Mo and titanium nitride (TiN) ceramic-coated resurfacing implants has led to excellent patient outcomes for more than 10 years. In clinical studies, 87% of patients with bilateral total hip replacements prefer their resurfacing-type total hip over their stem-type total hip. The author’s own personal resurfacing total hips, now at 8 and 5 years, respectively, provide “normal” function and no radiographic osteolysis. Conclusions: After 45 years of active evaluation, including mechanical design considerations, prosthetic design development, clinical and radiographic analysis of results, as well as availability of components cleared by the FDA 510 K process, the author has stated a personal preference for the BP Resurfacing Hip System. His excellent mid-term results in both of his resurfaced hips are similar to the long-term results presented in published studies.展开更多
文摘Background: Sagittal plane placement of the tibial component in total knee replacement (TKR) has important implications for maximizing the range of flexion motion, allowing collateral ligaments to function more normally, as well as providing ideal compressive loading on the tibial bone-prosthesis interface. This study attempts to quantify the normal posterior tibial slope (PTS) angle pre-operatively and post-operatively in osteoarthritic patients after using a conventional extramedullary tibial resection guide to assess its effectiveness. Methods: Forty-nine primary cementless total knee replacements in 34 osteoarthritic patients were measured radiographically pre-operatively and one year post-operatively to determine the PTS and its effect on range of motion. Lateral X-rays, using the anterior cortical line of the tibia, were employed for all measurements. Results: Pre-operative PTS measured 11.83˚ (range 5˚ - 18˚), while post-operative PTS of implanted tibial components measured 11.30o (range 4˚ - 18˚). The pre-operative range of motion of 112˚ (range 30˚ to 135˚) was improved to 119˚ (range 90˚ to 135˚) post-operatively after 1 year. Conclusions: Anterior tibial shaft referencing using a conventional extramedullary tibial resection guide provides an easy and convenient method for reproducing the anatomical PTS during TKR. This methodology provided improvement in average range of motion from 112˚ pre-operatively to 119˚ post-operatively at one year.
文摘Background: Resurfacing-type total hip replacement (THR) has been successfully developed over the past 50 years through collaborative efforts between engineers and surgeons. Much of the development was pursued by individuals or groups, each of which participated in adding further refinements to the implants, instruments and surgical procedures, thus minimizing the serious problems of wear, osteolysis, loosening and femoral neck fractures. The purpose of this study is to explore the development process to optimize the resurfacing total hip replacement into its current application. Methods: In the early 1980s, cementless resurfacing implants were developed using “thin shell” technology to minimize bony resection of the acetabulum and femoral head. Femoral components utilized short, non-porous coated, tapered straight stems to reduce shear stresses in the femoral neck to prevent fractures and stress shielding, while mechanically stabilizing and aligning the components. Acetabular components were anatomically designed to be recessed inside bony borders to avoid neck-cup impingement and loosening. Initially, ultrahigh molecular weight polyethylene (UHMWPE) was used as a bearing, but due to high levels of wear and osteolysis, it was replaced by wear-resistant highly crossed-linked polyethylene (HXLPE) in 2008. Results: Use of HXLPE as a bearing material in both Co-Cr-Mo and titanium nitride (TiN) ceramic-coated resurfacing implants has led to excellent patient outcomes for more than 10 years. In clinical studies, 87% of patients with bilateral total hip replacements prefer their resurfacing-type total hip over their stem-type total hip. The author’s own personal resurfacing total hips, now at 8 and 5 years, respectively, provide “normal” function and no radiographic osteolysis. Conclusions: After 45 years of active evaluation, including mechanical design considerations, prosthetic design development, clinical and radiographic analysis of results, as well as availability of components cleared by the FDA 510 K process, the author has stated a personal preference for the BP Resurfacing Hip System. His excellent mid-term results in both of his resurfaced hips are similar to the long-term results presented in published studies.
