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Maciąg BM, Stolarczyk A, Maciąg GJ, Dorocińska M, Stępiński P, Szymczak J, Świercz M, Żarnovsky K, Łapiński M, Stolarczyk M. Does the anatomic design of total knee prosthesis allow for a better component fit than its nonanatomic predecessor? A matched cohort Study. Arthroplast Today 2021; 12:62-67. [PMID: 34765714 PMCID: PMC8571411 DOI: 10.1016/j.artd.2021.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/29/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
Background Total knee arthroplasty (TKA) is considered the most efficient treatment of end-stage osteoarthritis. There is an ongoing debate about proper implant designs and articulation types. One of the considered causes of unsatisfactory outcome and patients’ dissatisfaction is femoral or tibial component overhanging, which can lead to chronic knee pain and restricted motion. The aim of this study is to compare radiological outcomes of TKA using an anatomic PERSONA Posterior-Stabilized (PS) knee design with its nonanatomic predecessor, the NexGen LPS. Methods A group of 39 patients who received the PERSONA PS system and 33 patients who received the NexGen LPS was included. PERSONA patients were matched to NexGen patients using a 0.1 propensity score threshold with priority given to exact matches. Anteroposterior, lateral, and long-leg radiographs were taken preoperatively and at 6 weeks postoperatively to perform radiological and statistical analysis. Results The PERSONA subgroup had statistically higher posterior condylar offset. There is no statistically significant difference in posterior condylar offset ratio. There were less cases of femoral notching, femoral overhang, and placing tibial baseplate in the medial overhang in the PERSONA PS subgroup than in the NexGen subgroup (each statistically significant). Occurrence of tibial underhang was not statistically significant. Conclusion Radiological assessment in short-term follow-up showed excellent results for PERSONA knee design with better fit to native femur and tibia. In comparison to its predecessor, it also spares more bone tissue. As the aforementioned parameters are risk factors of lesser clinical outcomes, the PERSONA design gives high hopes for improvement of TKA satisfaction rate.
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Affiliation(s)
- Bartosz M Maciąg
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Artur Stolarczyk
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Grzegorz J Maciąg
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Monika Dorocińska
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Piotr Stępiński
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Jakub Szymczak
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Maciej Świercz
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Krystian Żarnovsky
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Marcin Łapiński
- Department of Orthopedics and Rehabilitation, Medical University of Warsaw, Warsaw, Poland
| | - Magda Stolarczyk
- 3rd Clinic of Internal Medicine and Cardiology, Medical University of Warsaw, Warsaw, Poland
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Kang KT, Koh YG, Park KM, Lee JS, Kwon SK. Biomechanical analysis of a changed posterior condylar offset under deep knee bend loading in cruciate-retaining total knee arthroplasty. Biomed Mater Eng 2019; 30:157-169. [PMID: 30741664 DOI: 10.3233/bme-191041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The conservation of the joint anatomy is an important factor in total knee arthroplasty (TKA). The restoration of the femoral posterior condylar offset (PCO) has been well known to influence the clinical outcome after TKA. OBJECTIVE The purpose of this study was to determine the mechanism of PCO in finite element models with conservation of subject anatomy and different PCO of ±1, ±2, ±3 mm in posterior direction using posterior cruciate ligament-retaining TKA. METHODS Using a computational simulation, we investigated the influence of the changes in PCO on the contact stress in the polyethylene (PE) insert and patellar button, on the forces on the collateral and posterior cruciate ligament, and on the quadriceps muscle and patellar tendon forces. The computational simulation loading condition was deep knee bend. RESULTS The contact stresses on the PE insert increased, whereas those on the patellar button decreased as posterior condylar offset translated to the posterior direction. The forces exerted on the posterior cruciate ligament and collateral ligaments increased as PCO translated to the posterior direction. The translation of PCO in the anterior direction, in an equivalent flexion angle, required a greater quadriceps muscle force. CONCLUSIONS Translations of the PCO in the posterior and anterior directions resulted in negative effects in the PE insert and ligament, and the quadriceps muscle force, respectively. Our findings suggest that orthopaedic surgeons should be careful with regard to the intraoperative conservation of PCO, because an excessive change in PCO may lead to quadriceps weakness and an increase in posterior cruciate ligament tension.
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Affiliation(s)
- Kyoung-Tak Kang
- Department of Mechanical Engineering, Yonsei University, Seoul, Republic of Korea
| | - Yong-Gon Koh
- Department of Orthopaedic Surgery, Joint Reconstruction Center, Yonsei Sarang Hospital, Seoul, Republic of Korea
| | - Kyoung-Mi Park
- Department of Mechanical Engineering, Yonsei University, Seoul, Republic of Korea
| | - Jun-Sang Lee
- Department of Orthopaedic Surgery, Joint Reconstruction Center, Yonsei Sarang Hospital, Seoul, Republic of Korea
| | - Sae Kwang Kwon
- Department of Orthopaedic Surgery, Joint Reconstruction Center, Yonsei Sarang Hospital, Seoul, Republic of Korea
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Effect of the Referencing System on the Posterior Condylar Offset and Anterior Flange-Bone Contact in Posterior Cruciate-Substituting Total Knee Arthroplasty. J Arthroplasty 2018; 33:1069-1075. [PMID: 29195851 DOI: 10.1016/j.arth.2017.11.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/01/2017] [Accepted: 11/12/2017] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND The effect of referencing system on posterior condylar offset (PCO) after total knee arthroplasty (TKA) is still controversial. Moreover, there is a lack of concern about the anterior flange-bone contact according to the referencing system. METHODS One hundred four TKAs using the anterior referencing (AR) system and 107 TKAs using the posterior referencing (PR) system were analyzed with 2-year follow-up. The PCO, PCO ratio (PCOR), and contact at the anterior flange-bone interface were compared between the 2 groups. The flexion and extension gaps and the degree of medial release were measured, and clinical outcomes were evaluated. Finally, the correlation between changes in PCO and knee flexion angle was analyzed. RESULTS The mean postoperative PCO and PCOR were significantly larger in the PR group than in the AR group. Incomplete contact between the anterior flange and anterior femur occurred more frequently in the AR group than in the PR group (48.1% vs 13.1%, P < .001). The medial and lateral flexion gaps were significantly larger in the AR group than in the PR group. The groups showed no differences in soft tissue release, degree of flexion, and clinical scores. In both groups, there was no correlation between postoperative change of PCO and improvement in flexion. CONCLUSION The PR system produced larger PCO and PCOR, and smaller flexion gap compared to the AR system. Additionally, the PR group showed more favorable contact between the anterior flange and anterior femur. However, these differences were not related to the degree of soft tissue release and clinical outcomes.
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The intercondylar notch ceiling: an accurate reference for distal femoral resection in total knee arthroplasty for severely degenerated varus knees. Knee Surg Sports Traumatol Arthrosc 2017; 25:2818-2824. [PMID: 26387124 DOI: 10.1007/s00167-015-3792-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 09/10/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE To measure the distance from the intercondylar ceiling to the lowest point of the medial and lateral femoral condyles in a healthy population so to obtain a clearly discernible and accurate landmark for proper distal femoral resection during total knee arthroplasty (TKA). METHODS Three-dimensional models of the lower extremities of 100 healthy Chinese subjects were constructed using computed tomography scans. The distance between the distal surface of the medial femoral condyle and the intercondylar notch ceiling, in the direction of the femoral mechanical axis, was measured. RESULTS The mean distance from the distal surface of the medial femoral condyle to the intercondylar notch ceiling was 9.1 ± 1.4 and 8.2 ± 1.4 mm in male and female subjects, respectively. Interestingly, this distance did not differ significantly with varying sizes of the distal femur. CONCLUSIONS The intercondylar notch ceiling could be used as an accurate landmark to determine the proper distal femoral resection level during TKA. For the clinical relevance, the distal femoral bone cut should be at the level of the intercondylar notch ceiling when using the most of the current TKA prosthesis systems.
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Wang JT, Zhang Y, Liu Q, He Q, Zhang DL, Zhang Y, Xiao JX, Mu X, Hu M. Effect of posterior condylar offset on clinical results after posterior-stabilized total knee arthroplasty. Chin J Traumatol 2017; 18:259-66. [PMID: 26777708 DOI: 10.1016/j.cjtee.2015.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To determine the effect of the posterior condylar offset (PCO) on clinical results after total knee arthroplasty (TKA) using a high-flex posterior-stabilized (PS) fixed-bearing prosthesis. METHODS We prospectively studied the clinical and radiographic materials of 89 consecutive female patients (89 knees), who had undergone primary TKAs for end-stage osteoarthritis. All operations were performed by a single senior surgeon or under his supervision using the same operative technique. Based on the corrected PCO change, we divided all cases into two groups: group A (corrected PCO change ≥0 mm, 58 knees) and group B (corrected PCO change<0 mm, 31 knees). One-year postoperatively, clinical and radiographic variables from the two groups were compared by independent t-test. The associations between the corrected PCO changes and the improvements of clinical variables in all patients were analyzed by Pearson linear correlation. RESULTS One-year postoperatively, the Knee Society Scores, the Western Ontario and McMaster Universities Osteoarthritis Index, non-weight-bearing active and passive range of knee flexion, flexion contracture, extensor lag, and their improvements had no statistical differences between the two groups (all p>0.05). The corrected PCO change was not significantly correlated with the improvement of any clinical variable (all p>0.05). Group A demonstrated greater flexion than group B during active weight bearing (p<0.05). CONCLUSIONS Restoration of PCO plays an important role in the optimization of active knee flexion during weight-bearing conditions after posterior-stabilized TKA, while it has no benefit to non-weight-bearing knee flexion or any other clinical result.
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Affiliation(s)
- Jian-Tao Wang
- Department of Orthopedics, Nankai University Tianjin Union Medical Center, Tianjin 300121, China
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Minoda Y, Nakagawa S, Sugama R, Ikawa T, Noguchi T, Hirakawa M, Matsui Y, Nakamura H. Decreased extension gap and valgus alignment after implantation of total knee prosthesis in primary varus knees. Knee Surg Sports Traumatol Arthrosc 2016; 24:3642-3647. [PMID: 25311053 DOI: 10.1007/s00167-014-3381-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 10/09/2014] [Indexed: 11/29/2022]
Abstract
PURPOSE It was hypothesised that implantation of a total knee prosthesis may change the size and shape of the joint gap. To test this hypothesis, a tensor device was used which was specifically designed to reproduce the conditions before and after implantation, including attachment of the polyethylene insert trial. This study aimed to compare the joint gaps before and after implantation of a total knee prosthesis using this new tensor device. METHODS A total of 259 primary varus knees were included in this study. Knees were exposed using a medial parapatellar approach, and the anterior and posterior cruciate ligaments were resected. After the trial reduction, the intraoperative joint gap kinematics was measured using the tensor device. RESULTS Implantation of a total knee prosthesis decreased the size of the extension joint gap and made it valgus, but did not influence the size or shape of the flexion joint gap. CONCLUSIONS The present findings suggest that the classical gap technique, which creates equal and rectangular extension and flexion joint gaps in the bone cutting surface, results in an imbalance between the extension and flexion joint gaps after implantation. To achieve equal and rectangular extension and flexion joint gaps after implantation, the prepared extension joint gap should be about 2 mm larger than the flexion joint gap and slightly varus before implantation in primary varus knees. LEVEL OF EVIDENCE Therapeutic study, Level II.
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Affiliation(s)
- Yukihide Minoda
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi Abeno-ku, Osaka, 545-8585, Japan.
| | - Shigeru Nakagawa
- Department of Orthopaedic Surgery, Osaka Rosai Hospital, 1179-3 Nagasone-cho Kita-ku Sakai, Osaka, 591-8025, Japan
| | - Ryo Sugama
- Department of Orthopaedic Surgery, Osaka General Hospital, 3-1-56 Mandaihigashi Sumiyoshi-ku, Osaka, 558-8558, Japan
| | - Tessyu Ikawa
- Hanwa Joint Reconstruction Center, 3176 Fukaikitamachi Naka-ku Sakai, Osaka, 599-8271, Japan
| | - Takahiro Noguchi
- Department of Orthopaedic Surgery, Shinbeppu Hospital, 3898 Tsurumi Beppu, Oita, 874-0833, Japan
| | - Masashi Hirakawa
- Department of Orthopaedic Surgery, Oita University Faculty of Medicine Graduate School of Medicine, 1-1 Idaigaoka Hazama-cho Yufu, Oita, 879-5593, Japan
| | - Yoshio Matsui
- Department of Orthopaedic Surgery, Osaka Rosai Hospital, 1179-3 Nagasone-cho Kita-ku Sakai, Osaka, 591-8025, Japan
| | - Hiroaki Nakamura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi Abeno-ku, Osaka, 545-8585, Japan
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Itokazu M, Minoda Y, Ikebuchi M, Mizokawa S, Ohta Y, Nakamura H. Anatomical landmarks of the distal femoral condyles are not always parallel to the tibial bone cut surface in flexion during total knee arthroplasty. Knee 2016; 23:725-9. [PMID: 27117168 DOI: 10.1016/j.knee.2015.11.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/10/2015] [Accepted: 11/03/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND Soft tissue balancing is crucial to the success of total knee arthroplasty (TKA). To create a rectangular flexion joint gap, the rotation of the femoral component is important. The purpose of this study is to determine whether or not anatomical landmarks of the distal femoral condyles are parallel to the tibial bone cut surface in flexion. METHODS Forty-eight patients (three male and 45 female) with a mean age of 74years were examined. During the operation, we estimated the flexion joint gap with the following three techniques. 1) a three degree external cut to the posterior condylar line (MR1), 2) a parallel cut to the surgical transepicondylar axis (MR2), and 3) a parallel cut to the anatomical transepicondylar axis (MR3). RESULTS The flexion joint gap was 1.1±3.0° (mean±standard deviation (SD)) in internal rotation in the case of MR1, 0.9±3.4° in internal rotation in the case of MR2, and 2.1±3.4° in external rotation in the case of MR3. An outlier (flexion joint gap >3.0°) was observed in 12 cases (25%) in MR1, 13 cases (27%) in MR2, and 15 cases (31%) in MR3. CONCLUSIONS The anatomical landmarks of the distal femoral condyles are not always parallel to the tibial bone cut surface in flexion. To create a rectangular flexion joint gap, the rotation of the femoral component rotation is based not only on the anatomical landmarks but also on the ligament balance.
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Affiliation(s)
- Maki Itokazu
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Yukihide Minoda
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan.
| | - Mitsuhiko Ikebuchi
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Shigekazu Mizokawa
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Yoichi Ohta
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Hiroaki Nakamura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
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Han H, Oh S, Chang CB, Kang SB. Changes in femoral posterior condylar offset and knee flexion after PCL-substituting total knee arthroplasty: comparison of anterior and posterior referencing systems. Knee Surg Sports Traumatol Arthrosc 2016; 24:2483-8. [PMID: 26578306 DOI: 10.1007/s00167-015-3867-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 11/06/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE Anterior referencing and posterior referencing are two major techniques for positioning femoral components and balancing the sagittal plane during total knee arthroplasty (TKA). The purpose of this study was to evaluate the changes in medial and lateral posterior condylar offset (PCO) after bilateral TKA using anterior referencing (AR) or posterior referencing (PR) systems and compare the effect of the PCO changes on knee flexion. METHODS Twenty female patients (mean age, 68.6 years) underwent bilateral TKA using the AR technique in one knee and the PR technique in the contralateral knee. Three-dimensional reconstructed computed tomographic images from the sagittal plane were used to evaluate PCO before and after arthroplasty. Knee Society scores and range of motion were evaluated postoperatively at a mean of 2.9 years. RESULTS Postoperative medial and lateral PCOs were significantly greater (p < 0.001 and p = 0.048, respectively) in the AR group (30.9 ± 2.2 and 29.1 ± 1.5 mm, respectively) than those in the PR group (29.1 ± 2.7 and 27.3 ± 2.3 mm, respectively). In addition, the degree of change in the PCO after TKA was greater in the AR group than in the PR group. On the final follow-up, no differences in the degree of knee flexion were observed between the two groups (124.7° for AR and 124.5° for PR). Knee Society scores were similar in the two groups both preoperatively and postoperatively. On the final follow-up, individual changes in the medial and lateral PCO were not associated with changes in the knee flexion angle. CONCLUSIONS Restoration of PCO after TKA was more accurate with the PR technique than with the AR technique. However, the postoperative differences in PCO showed no correlation with changes in knee flexion 2 years after PCL-substituting TKA. LEVEL OF EVIDENCE Therapeutic study, Level I.
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Affiliation(s)
- Hyuksoo Han
- Department of Orthopedic Surgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea
| | - Sohee Oh
- Department of Biostatistics, Seoul National University Boramae Medical Center, 20 Boramae 5th Road, Dongjak-gu, Seoul, 156-707, South Korea
| | - Chong Bum Chang
- Department of Orthopedic Surgery, Seoul National University Boramae Medical Center, 20 Boramae 5th Road, Dongjak-gu, Seoul, 156-707, South Korea
| | - Seung-Baik Kang
- Department of Orthopedic Surgery, Seoul National University Boramae Medical Center, 20 Boramae 5th Road, Dongjak-gu, Seoul, 156-707, South Korea.
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Almeida PH, Vilaça A. The posterior condylar offset ratio and femoral anatomy in anterior versus posterior referencing total knee arthroplasty. Orthop Traumatol Surg Res 2015. [PMID: 26205566 DOI: 10.1016/j.otsr.2015.05.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
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.
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Affiliation(s)
- P H Almeida
- Centro Hospitalar do Porto, Largo Prof. Abel Salazar, 4099-001 Porto, Portugal.
| | - A Vilaça
- Centro Hospitalar do Porto, Largo Prof. Abel Salazar, 4099-001 Porto, Portugal
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Weinberg DS, Streit JJ, Gebhart JJ, Williamson DFK, Goldberg VM. Important Differences Exist in Posterior Condylar Offsets in an Osteological Collection of 1,058 Femurs. J Arthroplasty 2015; 30:1434-8. [PMID: 25783444 DOI: 10.1016/j.arth.2015.02.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/18/2015] [Accepted: 02/23/2015] [Indexed: 02/01/2023] Open
Abstract
Posterior condylar offset (PCO) has important implications in total knee arthroplasty (TKA) function and design. In an osteological study of 1,058 femurs, we measured PCO using two separate techniques with a 3D digitizer. Measurements were standardized for the size of the femur. The medial PCO was greater than lateral PCO (32.6mm vs. 31.2mm, P<0.0001). In 53% of individuals, the medial PCO differed between sides by more than 2mm. Age did not affect standardized medial or lateral PCO. Compared with African-Americans, Caucasians had a larger standardized medial (1.3mm vs. 1.2mm, P=0.006) and lateral (1.1mm vs. 1.0mm, P=0.004) PCOs. The standardized medial (1.2mm vs. 1.3mm, P=0.073), and lateral (1.1mm vs. 1.1mm, P=0.098), PCO did not differ between men and women, respectively.
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Affiliation(s)
- Douglas S Weinberg
- Department of Orthopaedic Surgery, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Jonathan J Streit
- Department of Orthopaedic Surgery, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Jeremy J Gebhart
- Department of Orthopaedic Surgery, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Drew F K Williamson
- Department of Orthopaedic Surgery, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Victor M Goldberg
- Department of Orthopaedic Surgery, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH, USA
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Intraoperative assessment of midflexion laxity in total knee prosthesis. Knee 2014; 21:810-4. [PMID: 24827697 DOI: 10.1016/j.knee.2014.04.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 04/07/2014] [Accepted: 04/10/2014] [Indexed: 02/02/2023]
Abstract
BACKGROUND Soft-tissue balancing of the knee is fundamental to the success of a total knee arthroplasty (TKA). In posterior-stabilized TKA, there is no stabilizer of the anterior-posterior translation in the midflexion range in which the cam-post mechanism does not engage yet. Therefore, instability in the midflexion range is suspected to occur in posterior-stabilized TKA. The purpose of this study was to measure the joint gap throughout a full range of motion and to analyze the joint gap laxity in the midflexion range after implantation of a mobile-bearing posterior-stabilized total knee prosthesis. METHODS Joint gap kinematics in 259 knees with varus osteoarthritis were measured during TKAs using a tensor device with the same shape of a total knee prosthesis of the same design was used. After the implantation of a mobile-bearing posterior-stabilized prosthesis and the reduction of the patellofemoral joint, the joint gap was measured at 0°, 30°, 60°, 90°, 120°, and 145° of flexion. RESULTS The center size of the joint gap was tight in extension and deep flexion and loose at midflexion ranges, especially at 30° of flexion (p<0.001). The symmetry of the joint gap was varus at 0° and 145° of flexion (p<0.001). CONCLUSIONS Our results showed the joint gap laxity in the midflexion range after the implantation of a mobile-bearing posterior-stabilized prosthesis. Our new tensor device, which can attach the polyethylene insert trial, will provide the important information about the joint gap kinematics after implantation of total knee prostheses. LEVEL OF EVIDENCE IV.
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Surgical technique: Computer-assisted sliding medial condylar osteotomy to achieve gap balance in varus knees during TKA. Clin Orthop Relat Res 2013; 471:1484-91. [PMID: 23283680 PMCID: PMC3613564 DOI: 10.1007/s11999-012-2773-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Extensive posteromedial release to correct severe varus deformity during TKA may result in mediolateral or flexion instability and may require a constrained implant. We describe a technique combining computer navigation and medial condylar osteotomy in severe varus deformity to achieve a primary goal of ligament balance during TKA. DESCRIPTION OF TECHNIQUE The goal of this procedure was to achieve mediolateral gap balance in varus knees with rigid, recalcitrant medial contracture, with or without excessive lateral laxity, not amenable to extensive medial soft tissue releases. A sliding medial condylar osteotomy (SMCO) was performed under navigation guidance and the condylar block internally fixed using cancellous screws. METHODS We prospectively evaluated mediolateral laxity, Knee Society scores, and knee ROM after SMCO in 12 varus arthritic knees in 11 patients (five men, six women) undergoing TKA with a minimum followup of 2 years (mean, 2 years; range, 2-2.5 years). RESULTS The degree of mediolateral knee laxity improved from Grade 2 (in four knees) and Grade 3 (in eight knees) preoperatively to Grade 1 (< 5 mm) in all knees at last followup. Mean Knee Society score improved from 30 (range, 10-54) to 92 (range, 86-100). Mean knee flexion improved from 106° (range, 90°-120°) to 112° (range, 100°-124°), and no knee had any extensor lag or residual flexion deformity (> 5°). Three knees had asymptomatic fibrous union at the osteotomy site. CONCLUSIONS Computer-assisted SMCO in varus knees with recalcitrant medial contracture achieves improved mediolateral stability and knee function after TKA. Our technique uses navigation to accurately reposition the medial condylar block to equalize medial and lateral gaps, thereby ensuring a stable well-aligned knee without deploying constrained implants.
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Minoda Y, Iwaki H, Ikebuchi M, Yoshida T, Nakamura H. The flexion gap preparation does not disturb the modified gap technique in posterior stabilized total knee arthroplasty. Knee 2012; 19:832-5. [PMID: 22516610 DOI: 10.1016/j.knee.2012.03.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 03/02/2012] [Accepted: 03/14/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE Preparation of the flexion gap (resection of the posterior femoral condyle and removal of the osteophytes on the posterior aspect of the femur to re-establish the posterior capsular recess) during modified gap technique might change the soft-tissue balancing and disturb the preparation of equal and rectangular extension and flexion joint gaps. The purpose of this study was to measure the change in the extension and flexion gaps using tension device during posterior stabilized TKA with modified gap technique. METHODS We examined changes in the extension gap and flexion gap during posterior stabilized TKA using modified gap technique in 100 consecutive varus osteoarthritis knees. The extension gap was first prepared and then the distance and angle of both extension and flexion gaps were measured before and after preparation of the flexion gap using a tension device. RESULTS Although both the extension and flexion gaps significantly increased during the operation, the amount of the increase was very small, and the difference between the increase in the extension gap (0.9 ± 0.1mm [mean ± SE]) and that in the flexion gap (0.7 ± 0.1mm) was not statistically significant. Mean angular changes in extension and flexion gaps during the operation were less than 1°. CONCLUSIONS The preparation of the flexion gap in posterior stabilized TKA did not disturb the modified gap technique in terms of equal and rectangular extension and flexion gaps.
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Affiliation(s)
- Yukihide Minoda
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
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