The influence of UKA Installation Error of Joint Line on Contact Mechanics and Kinematics of Knee Joint / 医用生物力学

Objective Aiming at the medial prosthetic loosening failure and lateral cartilage degeneration after unicompartmental knee arthroplasty ( UKA), the effects of prosthetic installation errors of joint line in UKA on knee contact mechanics and kinematics during different physiologic activities were studied using musculoskeletal multi-body dynamic method. Methods Taking the medial natural joint line as 0 mm error, six installation errors ofjoint line including ±2 mm, ±4 mm and ±6 mm were considered respectively, and seven musculoskeletal multi body dynamic models of medial UKA were established, to comparatively study the variations in knee contact mechanics and kinematics during walking and squatting. Results At 70% of walking gait cycle, compared with 0 mm error, the medial prosthetic contact force was increased by 127. 3% and the contact force of the lateral cartilage was decreased by 12. 0% under 2 mm elevation in joint line, the medial prosthetic contact force was close to 0 N, but the lateral cartilage contact forces were increased by 10. 1% under 4 mm reduction in joint line. The tibiofemoral total contact forces were increased by 19. 7% and decreased by 14. 2% under 2 mm elevation and 2 mm reduction in joint line, respectively. At the 100°knee flexion during squatting, compared with 0 mm error, the medial prosthetic contact force and the tibiofemoral total contact force increased by 31. 6% and 11. 1% under 2 mm elevation in joint line, and decreased by 24. 5% and 8. 5% under 2 mm reduction in joint line, respectively. The change in the lateral cartilage contact force was not marked. Moreover, at 70% of walking gait cycle, the varus angle decreased, the internal rotation and the anterior translation increased along with the elevation of joint line in UKA, while it was just the opposite along with the reduction of joint line in UKA. The trends of the varus valgus movement and anterior-posterior translation during squatting were consistent with those during swing phase of walking, but the trend of the internal-external rotation was opposite. Conclusions In order to reduce the risk of medial prosthetic loosening failure and lateral cartilage degeneration, it is recommended that the installation error of joint line in UKA should be controlled in the range of -2 mm to +2 mm. This study provides theoretical basis for UKA clinical failure caused by changes in joint line

Effect of prosthetic joint line installation height errors on insert wear in unicompartmental knee arthroplasty / 生物医学工程学杂志

The clinical performance and failure issues are significantly influenced by prosthetic malposition in unicompartmental knee arthroplasty (UKA). Uncertainty exists about the impact of the prosthetic joint line height in UKA on tibial insert wear. In this study, we combined the UKA musculoskeletal multibody dynamics model, finite element model and wear model to investigate the effects of seven joint line height cases of fixed UKA implant on postoperative insert contact mechanics, cumulative sliding distance, linear wear depth and volumetric wear. As the elevation of the joint line height in UKA, the medial contact force and the joint anterior-posterior translation during swing phase were increased, and further the maximum von Mises stress, contact stress, linear wear depth, cumulative sliding distance, and the volumetric wear also were increased. Furthermore, the wear area of the insert gradually shifted from the middle region to the rear. Compared to 0 mm joint line height, the maximum linear wear depth and volumetric wear were decreased by 7.9% and 6.8% at -2 mm joint line height, and by 23.7% and 20.6% at -6 mm joint line height, the maximum linear wear depth and volumetric wear increased by 10.7% and 5.9% at +2 mm joint line height, and by 24.1% and 35.7% at +6 mm joint line height, respectively. UKA prosthetic joint line installation errors can significantly affect the wear life of the polyethylene inserted articular surfaces. Therefore, it is conservatively recommended that clinicians limit intraoperative UKA joint line height errors to -2-+2 mm.

Conceptos actuales en osteotomías en doble nivel alrededor de la rodilla / Current concepts in double-level osteotomies around the knee

Con la osteotomía en un solo nivel, se puede lograr la corrección del eje de la extremidad en pacientes con deformidades combinadas femoral y tibial, pero de forma simultánea generará una alteración patológica de oblicuidad de la interlínea articular, lo que conducirá a elongación ligamentaria, inestabilidad, degeneración condral y, en última instancia, comprometerá su sobrevida y los resultados funcionales. En virtud del análisis de la literatura más reciente, podemos concluir que existe un número significativo de pacientes que requieren de un procedimiento combinado para lograr un objetivo biomecánico óptimo. La finalidad de una osteotomía en doble nivel alrededor de la rodilla consiste en restablecer la anatomía normal, descargar el compartimiento afectado, normalizar los ángulos mecánicos y la orientación de la interlínea articular. Los ejes fisiológicos pueden restablecerse a través de un análisis preoperatorio exhaustivo, respetando principios biomecánicos y fijación estable con placas bloqueadas. Es un procedimiento demandante y con indicaciones en evolución, que progresivamente se ha instaurado como una alternativa de tratamiento justificada en estudios clínicos y biomecánicos para el manejo de deformidades severas alrededor de la rodilla.

With single-level osteotomy, correction of the limb axis in patients with combined femoral and tibial deformities can be achieved. This correction, however, will generate a pathological alteration in the joint line oblicuity, leading to ligament elongation, instability, joint degeneration and, ultimately, it will compromise the longevity and functional results of the correction. By analyzing the most recent literature, we can conclude that there is a significant number of patients who require a combined procedure to achieve an optimal biomechanical goal. The purpose of a double-level osteotomy around the knee is to restore normal anatomy, unload the affected compartment, normalize the mechanical angles and the orientation of the joint line. Physiological axes can be reestablished by means of a thorough preoperative analysis, observing the biomechanical principles and stable fixation with locked plates. It is a demanding procedure with increasing indications, which has progressively been established in clinical and biomechanical studies as a justified treatment alternative for the management of severe deformities around the knee.

La importancia de la restauración de la línea articular en la revisión de la artroplastía total de rodilla. Índices funcionales, calidad de vida y supervivencia / The importance of the restoration of the joint line in revision total knee arthroplasty. Clinical indexes, quality of life and survival

Resumen: Introducción: La reproducción de la correcta línea articular podría ser un buen índice para la obtención de resultados satisfactorios en la cirugía protésica de rodilla, aunque en la cirugía de revisión no se ha estudiado ampliamente. Es necesaria la búsqueda de un método sencillo y reproducible para evaluar esos resultados. Material y métodos: Se realizó un estudio retrospectivo entre Enero del 2000 y Diciembre del 2013. Se implantaron 97 artroplastías totales de revisión de rodilla. El grupo de estudio lo conformaron 67 pacientes. Para la realización de nuestro trabajo se evaluó la línea articular según el método descrito por Hofmann A. La evaluación de los resultados clínicos incluyó las siguientes variables primarias: flexión, extensión, rango de movimiento, WOMAC, SF-36, KSS (Knee Society Score) y KSS funcional. Se estudió la supervivencia de las artroplastías. Resultados: Las variables de flexión, extensión y rango de movimiento postoperatorio se correlacionaron estadísticamente con esta medición. El KSS se relacionó estadísticamente en su vertiente articular con la restauración de la línea articular. Para el resto de escalas, SF-36 y WOMAC, las puntuaciones fueron más altas pero no se correlacionó con la significación aceptada. Conclusión: Ante estos resultados podemos afirmar que la restauración de la correcta línea articular mejora los resultados clínicos de la cirugía de revisión de rodilla.

Abstract: Introduction: The reproduction of the anatomical joint line could be a good index to obtain good results in knee prosthesis surgery, although in revision surgery has not been enough studied. A search for a simple and reproducible method is needed to review these results. Material and methods: A retrospective study was conducted between January 2000 and December 2013. A total of 97 total revision knee arthroplasties were implanted. Finally, the study group consisted of 67 patients. To perform our study, the joint line was evaluated according to the method described by Hofmann A. The evaluation of the clinical results included the following main variables: Flexion, extension, range of motion, WOMAC, SF-36, KSS (Knee Society Score) and functional KSS. The survival of the arthroplasties was studied. (p = 0.05). Results: The variables of flexion, extension and range of postoperative movement are statistically correlated with this measure. The KSS was statistically related in its joint aspect with the restoration of the joint line. For the other scales, SF-36 and WOMAC, the figures were higher but did not correlate with the accepted p. Conclusion: In view of these results, we can say that the restoration of the anatomical joint line improves the clinical results of revision total knee arthroplasty.

Changes in Femoral Posterior Condylar Offset, Tibial Posterior Slope Angle, and Joint Line Height after Cruciate-Retaining Total Knee Arthroplasty

PURPOSE: Changes in the femoral posterior condylar offset (PCO), tibial posterior slope angle (PSA), and joint line height (JLH) after cruciate-retaining total knee arthroplasty (CR-TKA) were evaluated to determine their influence on the flexion angle. MATERIALS AND METHODS: A total of 125 CR-TKAs performed on 110 patients were retrospectively reviewed. Pre- and postoperative PCO, PSA, and JLH were compared using correlation analysis. Independent factors affecting the postoperative flexion angle of the knee were analyzed. RESULTS: The PCO was 28.2+/-2.0 mm (range, 24.5 to 33.1 mm) preoperatively and 26.7+/-1.8 mm (range, 22.2 to 31.2 mm) postoperatively (r=0.807, p0.291). CONCLUSIONS: Although the PCO and JLH did not change significantly after CR-TKA, the PSA decreased by 5.5degrees with a small range of variation. Restoration of the PCO and JLH could promote optimization of knee flexion in spite of the decreased PSA after CR-TKA.

Avaliação radiológica da osteoartrose de joelhos: vista póstero-anterior do túnel ou ântero-posterior com carga em extensão? / Radiological evaluation of osteoarthrosis of the knee: weight bearing posteroanterior tunnel view or weight bearing anteroposterior view in extension?

Objetivo: Verificar se há diferença entre as medidas da fenda articular do joelho nas incidências radiográficas em ântero-posterior (AP), com carga e o joelho totalmente estendido, e a vista póstero-anterior do túnel (VPAT), com carga e joelho flexionado cerca de 30 graus. Materiais e métodos: Foram avaliados radiologicamente 50 pacientes do sexo feminino, acima de 40 anos, com sintomas clínicos e sinais radiológicos de osteoartrose (OA) nos joelhos, enquadradas nos graus II e III, de acordo com a classificação de Kellgren e Lawrence. As medidas foram feitas por dois ortopedistas cegos entre si que utilizaram um paquímetro digital. Os pontos da fenda articular determinados para medida foram a 10 mm da borda e no ponto médio dos compartimentos medial e lateral. As medidas em ambas as técnicas foram comparadas segundo teste t Student. Resultados: O método AP com carga apresentou médias maiores para as medidas realizadas nos pontos médios do compartimento lateral em ambos os lados. Para todos os demais pontos de medidas, as médias foram inferiores às observadas na incidência vista póstero-anterior do túnel. Conclusões: Não houve diferença estatística nas medições do espaço articular do joelho nas duas incidências, AP e VPAT.

The accuracy of joint line tenderness in the diagnosis of meniscal tears / Precisión del dolor en la línea de la articulación en el diagnóstico del desgarro meniscal

The accuracy of joint line tenderness in the diagnosis of meniscal tears was assessed in 129 knees. Arthroscopy was performed in each case to establish the diagnosis. The diagnosis was correct in 100 knees (77.5%) and incorrect in 29 (22.5%). A preoperative diagnosis of a medial meniscal tear was made in 63 knees and confirmed in 46 (73%) at arthroscopy. There were 46 true-positive, 17 false-positive, four false-negative and 62 true-negative results for the medial side. A lateral meniscal tear was suspected in 45 knees and confirmed in 39 (86.7%). Thus, 39 true-positive, six false-positive, two false-negative, and 82 true-negative interpretations were found. In this study, joint line tenderness as a test for lateral meniscal tears was accurate (93%), sensitive (95%), and specific (93%), but for medial tears the rates were lower.

La precisión del dolor en la línea de la articulación a la hora de hacer el diagnóstico del desgarro meniscal fue evaluada en 129 rodillas. En cada uno de los casos se realizó una artroscopia a fin de determinar el diagnóstico. El diagnóstico fue correcto en 100 rodillas (77.5%) e incorrecto en 29 (22.5%). Se llevó a cabo un diagnóstico preoperatorio del desgarramiento meniscal medial en 63 rodillas, confirmado en 46 (73%) por artroscopia. Hubo 46 resultados verdadero-positivos, 17 falsopositivos, 4 falso-negativos y 62 verdadero-negativos para el lado medial. Se sospechó un desgarro meniscal lateral en 45 rodillas, y se confirmó en 39 (86.7%). Por consiguiente, se hallaron 39 interpretaciones verdadero-positivas, 6 falso-positivas, 2 falso-negativas, y 82 verdadero-negativas. En este estudio, el dolor en la línea de la articulación como prueba para el desgarro meniscal lateral fue preciso (93%), sensible (95%), y específico (93%), pero para el desgarro medial los índices fueron más bajos.

Clinical Findings of the CompleteRadial Rupture of the Meniscal Root Ligament of the Medial Meniscus Posterior Horn: Preliminary Report / 대한정형외과학회잡지

PURPOSE: To evaluate the clinical findings of a complete radial rupture of the meniscal root ligament of the medial meniscus posterior horn. MATERIALS AND METHODS: From April, 2004 to December, 2004, nineteen patients (mean age, 56.5 years old) who were diagnosed with a medial root ligament rupture of the medial meniscus posterior horn during an arthroscopic treatment were enrolled in this study. The clinical findings, physical examinations, and the radiological and arthroscopic findings were analyzed retrospectively. RESULTS: Thirteen out of the nineteen cases had tenderness of the knee without specific trauma. The preoperative physical examination revealed posteromedial joint line tenderness in fifteen cases. A medial joint line protrusion with direct tenderness was observed in six cases (31.5%) and a positive McMurray test was observed in seventeen cases (89.5%). MRI was carried out in sixteen patients. All sixteen patients were diagnosed with a rupture of the meniscal root ligament using the author's diagnostic MRI criteria. CONCLUSION: Non-traumatic pain and posteromedial joint line tenderness in patients in their sixth decade are indications of a rupture of the meniscal root ligament of the medial meniscus posterior horn. Confirmation using MRI and arthroscopy is important for making a diagnosis.

The Change of the Coronal Joint Line Level after PCL preserving and substituting Total Knee Arthroplasty

PURPOSE: The change of the joint line is associated not only with bone cutting levels but also balance of soft tissue. The main objective of this study analyze to compare the changes of the coronal joint line levels between PCL retaining total knee arthroplasty and PCL-substituting total knee arthroplasty, using the new method designed by authors. MATERIAL AND METHODS: A total 44 knees of 22 patients who received both TKA, of whom the one side was CR TKA and the other side was PS TKA, were analysed on pre- and post-operative weight-bearing anteroposterior radiopraphy of the knee. The joint line levels were measured two times by one author and one time by different author. RESULTS: The proximal shift of the joint line showed differently in both groups. The average of shifting values were 2.4+/-4.1 mm in CR TKAs, and 5.4+/-5.8 mm in PS TKAs. PS TKAs had significantly larger shifting value than CR TKAs for all times(p<0.05). CONCLUSION: The results of this study showed that the joint line level proximally shifted after TKA, using measured resection technique and gap technique. The shifting level in PS TKA was larger than CR TKA. But it is difficult to predict the change of joint line level after TKA, because of deviation between case by case and the standard deviation of the measured value was 4~6 mm.

Comparison of Joint Line Change in Posterior Cruciate Retained versus Cruciate Sacrificed Total Knee Aarthroplasty / 대한정형외과학회잡지

PURPOSE: The purpose of this study is to compare the change of joint line and patellar position between posterior crucate ligament-retained and posterior cruciate ligament-sacrificed total knee arthroplasty. MATERIALS AND METHODS: Fifty posterior crucate ligament-retained and fifty posterior cruciate-sacrificed total knee arthroplasties were evaluated to compare the joint line height from tibial tuberosity, patella bone height from joint line, patella articular height from joint line, patella bone height from tibial tuberoisty and patella articular height from tibial tuberosity. The measurements were assessed preoperatively and postoperatively. RESULTS: No difference in joint line height from tibial tuberosity, patellar bone height from joint line, patellar articualr height from joint line, patellar bone height from tibial tuberosity and patellar articular height from tibial tuberosity were found with either design (p>0.05). CONCLUSION: This study demonstrates that the resection of the posterior cruciate ligament can be one of the preferable method to increase the flexion gap without influencing the joint line in Total knee arthroplasty.

The acceptable range of the changes of tibiofemoral and patellofemoral joint position in PCL retaining TKA for improved clinical results / 대한정형외과학회잡지

PURPOSE: to find out the change and limit of the changes of tibiofemoral joint line, patellar position and other related variables for improved postoperative knee function after PCL retaining TKRA. MATERIALS AND METHODS: The variables mentioned above were measured from the plain radiographs of 101 knees with PCL retaining TKRAs, correlated with clinical outcomes such as HSS score, range of motion and anterior knee pain. Then they were analyzed statistically. RESULTS: Tibiofemoral joint line, patellar height and femoral condylar size affected clinical outcomes. Excellent postoperative knee function resulted when the shift of tibiofemoral joint line position was between 5mm inferiorly to 5mm superiorly, postoperative patellar height between 15mm to 30mm, and the change of the femoral condylar size between 10mm decrease and 5mm increase. CONCLUSION: Excellent clinical results would be expected if the changes of the joint line position are kept within the range suggested in this paper.

Joint Line Change in Total Knee Replacement Arthroplasty / 대한정형외과학회잡지

It has been reported that the maintenance of proper ligament balance around the knee joint and the proper location of tibio-femoral joint line position are very important factors for obtaining good knee joint function after the total knee replacement arthroplasty. but, yet the exact effect of the change of joint line on the result of total knee replacement arthroplasty has not been elucidated. The purpose of this study is to evaluate the effect of the change of joint line on the patellar position and the postoperative knee joint function as well as the effect of antero-posterior offset of tibial component on the clinical result. The authors performed the clinical and radiological analysis of 85 knees, in which total knee replacement arthroplasty was performed and followed over 1 year. Tibio-femoral joint line changed from -7mm to +6.8mm (average -0.07) and in this range, the change of joint line did not influence the clinical result and the patellar position. As tibio-femoral joint line migrated proximally, the patella migrated distally and as tibio-femoral joint line migrated distally, the patella migrated proximally. Postoperative pain decreased as the patella and patellar articular surface moved proximally. As the patellar bone height from tibial tuberosity decreased postoperatively. The range of motion decreased. Antero-ppsterior offset of tibial component distributed from -4.2mm to +4.5mm (average 0.62mm) and no effect on cllinical result in this range. In conclusion, it may be suggested that the change of joint line in total knee replacement arthroplasty must be changed as little as possible for the good postoperative range of motion and relief of pain.