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Background: The postoperative posterior condylar offset ratio (PCOR) and the anterior femoral cut (AFC) after total knee arthroplasty in the anterior referencing system (ARS) and posterior referencing system (PRS) are controversial. Objective: To compare PCOR and AFC in both referencing systems. Materials and Methods: The present study was a retrospective study that included 331 patients with 443 knees that underwent primary PSTKA. The patients were divided into two groups according to the referencing system. One hundred four knees were selected for the ARS and 104 knees were selected for the PRS by using the systematic sampling method. Preoperative PCOR, postoperative PCOR, and AFC were measured and compared in each group and between groups. Results: Preoperative PCOR and postoperative PCOR in the ARS and PRS were 0.47 (SD 0.04). Postoperative PCOR in the ARS and PRS were not significantly different (p=0.43). The gaps between the tip of the anterior flange of the femoral component and anterior femoral cortex were 24.04% in the ARS and 28.85% in the PRS, with no statistically significant difference (p=0.43). Anterior femoral notching was not found in either group. Conclusion: Both ARS and PRS could preserve the PCOR and showed no statistically significant difference in the AFC after total knee arthroplasty. [ABSTRACT FROM AUTHOR]

Abstract Background We sought to determine whether there was a difference in the posterior condylar offset (PCO), posterior condylar offset ratio (PCOR) and clinical outcomes following total knee arthroplasty (TKA) with anterior referencing (AR) or posterior referencing (PR) systems. We also assessed whether the PCO and PCOR changes, as well as patient factors were related to range of motion (ROM) in each referencing system. Methods This retrospective study included 130 consecutive patients (184 knees) with osteoarthritis who underwent primary posterior cruciate ligament (PCL)-substituting fixed-bearing TKA. The difference between preoperative and postoperative PCO and PCOR values were calculated. Clinical outcomes including ROM and Western Ontario and McMaster University (WOMAC) scores were evaluated. Furthermore, multiple linear regression analysis was performed to determine the factors related to postoperative ROM in each referencing system. Results The postoperative PCO was greater in the AR group (28.4 mm) than in the PR group (27.4 mm), whereas the PCO was more consistently preserved in the PR group. The mean postoperative ROM after TKA was greater in the AR group (129°) than in the PR group (122°), whereas improvement in WOMAC score did not differ between the two groups. Preoperative ROM was the only factor related to postoperative ROM in both groups. Conclusions There was no difference in postoperative PCO in AR and PR group and the PCO was not associated with postoperative ROM. PCO was more consistently preserved after surgery in the PR group. The postoperative PCO and PCOR changes did not affect the postoperative ROM. Furthermore, similar clinical outcomes were achieved in the AR and PR groups. Trial registration Retrospectively registered (Trial registration number: 06-2010-110).

Background: We sought to determine whether there was a difference in the posterior condylar offset (PCO), posterior condylar offset ratio (PCOR) and clinical outcomes following total knee arthroplasty (TKA) with anterior referencing (AR) or posterior referencing (PR) systems. We also assessed whether the PCO and PCOR changes, as well as patient factors were related to range of motion (ROM) in each referencing system. Methods: This retrospective study included 130 consecutive patients (184 knees) with osteoarthritis who underwent primary posterior cruciate ligament (PCL)-substituting fixed-bearing TKA. The difference between preoperative and postoperative PCO and PCOR values were calculated. Clinical outcomes including ROM and Western Ontario and McMaster University (WOMAC) scores were evaluated. Furthermore, multiple linear regression analysis was performed to determine the factors related to postoperative ROM in each referencing system. Results: The postoperative PCO was greater in the AR group (28.4 mm) than in the PR group (27.4 mm), whereas the PCO was more consistently preserved in the PR group. The mean postoperative ROM after TKA was greater in the AR group (129°) than in the PR group (122°), whereas improvement in WOMAC score did not differ between the two groups. Preoperative ROM was the only factor related to postoperative ROM in both groups. Conclusions: There was no difference in postoperative PCO in AR and PR group and the PCO was not associated with postoperative ROM. PCO was more consistently preserved after surgery in the PR group. The postoperative PCO and PCOR changes did not affect the postoperative ROM. Furthermore, similar clinical outcomes were achieved in the AR and PR groups. Trial registration: Retrospectively registered (Trial registration number: 06-2010-110). [ABSTRACT FROM AUTHOR]

Background: The effect of posterior condylar offset (PCO) on maximal flexion of the knee after TKA is controversial. Another parameter, the posterior condylar offset ratio (PCOR), has been recently introduced to describe the posterior condylar geometry. This study measured the posterior femoral condyle geometry of a Chinese population and compared with those of a Western population published in the literature. Methods: We measured the PCO and PCOR of 100 Chinese knees (50 males, 50 females). The distances from the anterior and posterior femoral shaft cortex line to the most posterior femoral condyle tangent line were defined as the anterior-posterior dimension (ACP) and posterior condylar offset (PCO). The PCOR was calculated as PCO/ ACP. The measured PCO and PCOR were compared to those of a Western population reported in the literature. Results: The PCOs were 25.80 ± 2.71 and 27.32 ± 2.34 mm for the Chinese females and males, respectively, where the PCO of the females was significantly smaller than that of the males (p b 0.05). The PCORs were 0.47 ± 0.04 and 0.46 ± 0.03 for the Chinese females and males, respectively, where the PCORs were similar among the Chinese males and females (p > 0.05). Conclusions: While the PCO of the Chinese females was smaller than that of the males, their PCORs were similar. Compared to the data of a Western population reported in literature, the PCO of the Chinese population is significantly smaller, but the PCOR is significantly larger. [ABSTRACT FROM AUTHOR]

Background: The preservation of joint anatomy is one of the key issues in total knee arthroplasty. The effect of the prosthesis' referencing system, relative to femoral anatomy, remains unknown. It was sought to determine if femoral anatomy, following total knee arthroplasty is better maintained using either anterior referencing or posterior referencing prosthesis. The posterior condylar offset ratio (PCOR) was employed for preoperative and postoperative radiographic comparison of femoral condyles. It was hypothesized that posterior referencing prosthesis would better restore condylar morphology., Methods: Sixty-six patients undergoing a total knee arthroplasty with anterior referenced Zimmer(®) NexGen(®) LPS prosthesis and ninety-one with posterior referenced Tornier(®) HLS Noetos(®) were divided into two groups according to the prosthetic model used and retrospectively compared. PCOR was calculated as the quotient of the distance between the posterior condylar border and the tangent to the posterior cortex of the femoral diaphysis, and the distance between the posterior condylar border and the tangent to the anterior cortex of the femoral diaphysis. PCOR was determined preoperatively and postoperatively and compared within each group and between both groups., Results: An increase in the PCOR (P<0.0001) following surgery was observed in both anterior referencing and posterior referencing models. No difference was noted when the postoperative PCOR was compared between both groups (P=0.61)., Conclusion: Both anterior and posterior referencing prosthesis lead to a similar increase of the PCOR following total knee arthroplasty., Level of Evidence: Level IV., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Background: The effect of posterior condylar offset (PCO) on maximal flexion of the knee after TKA is controversial. Another parameter, the posterior condylar offset ratio (PCOR), has been recently introduced to describe the posterior condylar geometry. This study measured the posterior femoral condyle geometry of a Chinese population and compared with those of a Western population published in the literature., Methods: We measured the PCO and PCOR of 100 Chinese knees (50 males, 50 females). The distances from the anterior and posterior femoral shaft cortex line to the most posterior femoral condyle tangent line were defined as the anterior-posterior dimension (ACP) and posterior condylar offset (PCO). The PCOR was calculated as PCO/ACP. The measured PCO and PCOR were compared to those of a Western population reported in the literature., Results: The PCOs were 25.80±2.71 and 27.32±2.34 mm for the Chinese females and males, respectively, where the PCO of the females was significantly smaller than that of the males (p<0.05). The PCORs were 0.47±0.04 and 0.46±0.03 for the Chinese females and males, respectively, where the PCORs were similar among the Chinese males and females (p>0.05)., Conclusions: While the PCO of the Chinese females was smaller than that of the males, their PCORs were similar. Compared to the data of a Western population reported in literature, the PCO of the Chinese population is significantly smaller, but the PCOR is significantly larger., (Copyright © 2013 Elsevier B.V. All rights reserved.)