Objective： To study whether the range of knee flexion （ROF） is affected by geometrical mismatch of the femoral component and the resultant change in the pos- terior condylar offset （PCO） after high-flexion poster...Objective： To study whether the range of knee flexion （ROF） is affected by geometrical mismatch of the femoral component and the resultant change in the pos- terior condylar offset （PCO） after high-flexion posterior-sta- bilized total knee arthroplasty （TKA）. Methods： One hundred osteoarthritic patients （50 males and 50 females） underwent femoral osteotomy by the ante- rior referencing technique. The PCO for each patient was measured from lateral radiographs before, during and 2 years after TKA. The thickness of the joint cartilage was mea- sured by magnetic resonance imaging before TKA and added onto the radiographic measurement. The relationship between changes in the PCO and improvements in the ROF before, during and 2 years after TKA were statistically analyzed. Results： Compared with the preoperative value, the PCO was reduced by （3.45±3.28） mm after TKA, with a significantly larger reduction observed in female patients than male patients （P〈0.05）. When examining the subject popu- lation as a whole, there was a significant positive correla- tion between PCO and ROF improvement during TKA （P〈 0.05）, but this improvement was not maintained 2 years after TKA （P〉0.05）. However, when male and female patients were analyzed separately, there was a significant positive correlation between PCO change and ROF improvement for both sexes at both time points （all P〈0.05）. Conclusions： Restoration of PCO plays an important role in the optimization of knee flexion even after posteriorstabilized TKA. Femoral components based on Caucasian anatomic characteristics could not match the native anatomy of distal femurs in Chinese population especially female Chinese. Rotated resection of distal femur with anterior referencing technique usually leads to a decreased PCO and therefore reduces maximal obtainable flexion.展开更多
Objective： To detail our early experi- ence and technique of a modified two-stage reimplantation protocol using antibiotic-loaded articulating cement spac- ers （ALACSs） for treatment of late periprosthetic infectio...Objective： To detail our early experi- ence and technique of a modified two-stage reimplantation protocol using antibiotic-loaded articulating cement spac- ers （ALACSs） for treatment of late periprosthetic infection after total knee arthroplasty （TKA）. Methods： From January 2006 to February 2009, a series of 21 patients （21 knees） with late infected TKAs were treated by radical debridement and removal of all components and cement, and then articulating spacers were implanted using antibiotic-impregnated bone cement. For this purpose, 4 g vancomycin powder was mixed with per 40 g cement. Gradu- ated knee motion and partial weight bearing activity were encouraged in the interval period. Each patient received an individual systemic organism-sensitive antimicrobial therapy for 4.9 （range, 2-8） weeks followed by a second-stage TKA revision. All the patients were regularly followed up using the American Knee Society Scoring System. Results： Each case underwent a successful two-stage exchange and had infection eradicated, none had recurrent infection after an average of 32.2 （range, 17-54） months of follow-up. Preoperatively, the mean knee score was 53.5 points, function score was 27.3 points, pain score was 25.7 points, range of motion （ROM） was 82.0°, extensor lag was 2°. Between stages, the mean knee score was increased to 61.3 points, function score to 45 points, pain score to 35 points, ROM to 88.2°, and extensor lag to 3.4°. At final fol- low-up, the mean knee score was further increased to 82.1 points, function score to 74.5 points, pain score to 42.1 points, ROM to 94.3°, and knee extension lag to 1.9°. The interval period was 11.5 （range, 6-32） weeks. The amount of bone loss was unchanged between stages. No patient de- veloped noticeable dysfunction of the liver or kidney or other complications such as impaired wound healing, deep venous thrombosis, pulmonary embolism, cerebrovascular accidents, etc. Conclusions： Treating infected TKA with ALACS avoids spacer-related bone loss, preserves knee function between stages, and eradicates infection effectively with- out significant complications. The early clinical results are inspiring. The authors believe that radical and repeated （if needed） debridement, individual application of systemic antibiotics, and reasonable timing judgement upon the sec- ondary revision are all key factors related to a successful outcome with two-stage reimplantation procedure for in- fected TKA.展开更多
文摘Objective： To study whether the range of knee flexion （ROF） is affected by geometrical mismatch of the femoral component and the resultant change in the pos- terior condylar offset （PCO） after high-flexion posterior-sta- bilized total knee arthroplasty （TKA）. Methods： One hundred osteoarthritic patients （50 males and 50 females） underwent femoral osteotomy by the ante- rior referencing technique. The PCO for each patient was measured from lateral radiographs before, during and 2 years after TKA. The thickness of the joint cartilage was mea- sured by magnetic resonance imaging before TKA and added onto the radiographic measurement. The relationship between changes in the PCO and improvements in the ROF before, during and 2 years after TKA were statistically analyzed. Results： Compared with the preoperative value, the PCO was reduced by （3.45±3.28） mm after TKA, with a significantly larger reduction observed in female patients than male patients （P〈0.05）. When examining the subject popu- lation as a whole, there was a significant positive correla- tion between PCO and ROF improvement during TKA （P〈 0.05）, but this improvement was not maintained 2 years after TKA （P〉0.05）. However, when male and female patients were analyzed separately, there was a significant positive correlation between PCO change and ROF improvement for both sexes at both time points （all P〈0.05）. Conclusions： Restoration of PCO plays an important role in the optimization of knee flexion even after posteriorstabilized TKA. Femoral components based on Caucasian anatomic characteristics could not match the native anatomy of distal femurs in Chinese population especially female Chinese. Rotated resection of distal femur with anterior referencing technique usually leads to a decreased PCO and therefore reduces maximal obtainable flexion.
文摘Objective： To detail our early experi- ence and technique of a modified two-stage reimplantation protocol using antibiotic-loaded articulating cement spac- ers （ALACSs） for treatment of late periprosthetic infection after total knee arthroplasty （TKA）. Methods： From January 2006 to February 2009, a series of 21 patients （21 knees） with late infected TKAs were treated by radical debridement and removal of all components and cement, and then articulating spacers were implanted using antibiotic-impregnated bone cement. For this purpose, 4 g vancomycin powder was mixed with per 40 g cement. Gradu- ated knee motion and partial weight bearing activity were encouraged in the interval period. Each patient received an individual systemic organism-sensitive antimicrobial therapy for 4.9 （range, 2-8） weeks followed by a second-stage TKA revision. All the patients were regularly followed up using the American Knee Society Scoring System. Results： Each case underwent a successful two-stage exchange and had infection eradicated, none had recurrent infection after an average of 32.2 （range, 17-54） months of follow-up. Preoperatively, the mean knee score was 53.5 points, function score was 27.3 points, pain score was 25.7 points, range of motion （ROM） was 82.0°, extensor lag was 2°. Between stages, the mean knee score was increased to 61.3 points, function score to 45 points, pain score to 35 points, ROM to 88.2°, and extensor lag to 3.4°. At final fol- low-up, the mean knee score was further increased to 82.1 points, function score to 74.5 points, pain score to 42.1 points, ROM to 94.3°, and knee extension lag to 1.9°. The interval period was 11.5 （range, 6-32） weeks. The amount of bone loss was unchanged between stages. No patient de- veloped noticeable dysfunction of the liver or kidney or other complications such as impaired wound healing, deep venous thrombosis, pulmonary embolism, cerebrovascular accidents, etc. Conclusions： Treating infected TKA with ALACS avoids spacer-related bone loss, preserves knee function between stages, and eradicates infection effectively with- out significant complications. The early clinical results are inspiring. The authors believe that radical and repeated （if needed） debridement, individual application of systemic antibiotics, and reasonable timing judgement upon the sec- ondary revision are all key factors related to a successful outcome with two-stage reimplantation procedure for in- fected TKA.
