Increase In Posterior Tibial Slope Research Articles

Effect of plate position on tibial displacement and posterior tibial slope after cyclic loading in medial open wedge high tibial osteotomy: A biomechanical study using porcine tibia

BackgroundMedial open wedge high tibial osteotomy is currently the most common osteotomy, but its complication is an increased posterior tibial slope over time. However, no study has clarified whether the plate position of medial open wedge high tibial osteotomy could reduce the increase in posterior tibial slope after cyclic loading. MethodsFourteen porcine bones were biomechanically evaluated by performing medial open wedge high tibial osteotomy and placing TOMOFIX medially and anteromedially. Cyclic testing was performed to investigate the posterior tibial slope over time for medial open wedge high tibial osteotomy with medial or anteromedial plate. The displacement along the mechanical axis during cyclic testing from 10 to 100th, 100–500th, 500–1000th, 1000–1500th, and 1500–2000th cycles, and changes in anterior and posterior gaps after 2000 cycles were compared between plate position. FindingsThere were no significant differences in displacement. A significant difference was found in posterior gap changes (−0.20 ± 0.84 mm in group of using medial plate, 1.07 ± 0.82 mm in group of using anteromedial plate) (P = 0.014), but none was found in anterior gap changes. InterpretationMedial plate placement in medial open wedge high tibial osteotomy resulted in significantly less increased posterior tibial slope than anteromedial plate placement after cyclic loading.

The Blackburne–Peel Index for Determining Patellar Height Is Affected by Tibial Slope

PurposeTo establish a quantitative relationship between the Blackburne–Peel index and posterior tibial slope in both skeletally mature and skeletally immature individuals and to evaluate the rate at which variation in tibial slope influences changes in patellar height categorization as normal, patella alta, and patella baja.MethodsA consecutive series of lateral knee radiographs were retrospectively reviewed. Radiographs were excluded for rotation, inadequate visible proximal tibia length, and obstructive hardware/pathology. Modified tibial slopes of 0°, 5°, 10°, and 15° were projected anteriorly from the medial tibial plateau as described by Blackburne–Peel. The Blackburne–Peel index was determined at each modified tibial slope interval. Caton–Deschamps and Insall–Salvati indices also were measured for comparison. The rate of Blackburne–Peel index change with increase in posterior tibial slope was quantitatively analyzed.ResultsFifty skeletally mature and 50 skeletally immature radiographs were included. In the skeletally mature, Blackburne–Peel indices decreased on average by 0.037, 0.044, and 0.049 as posterior tibial slope increased from 0-5°, 5-10°, and 10-15°, respectively. In the skeletally immature, Blackburne–Peel indices decreased on average by 0.045, 0.053, and 0.059 as posterior tibial slope increased from 0-5°, 5-10°, and 10-15°, respectively. Overall, 29 individuals with 0° of tibial slope were categorized as patella alta by the Blackburne–Peel index, and only 16 (55%) remained categorized as patella alta after increasing their posterior tibial slope to 15°.ConclusionsThis study quantitatively demonstrates the relationship between posterior tibial slope and the Blackburne–Peel index. As expected, as posterior tibial slope increases, the Blackburne–Peel index decreases. While the change in the Blackburne–Peel index per 5° change in tibial slope appears to be small, nearly half (45%) of individuals categorized as patella alta with 0° of tibial slope were categorized as normal when their posterior tibial slope was systematically increased from 0° to 15°. When evaluating patellar height, it is important to understand how tibial slope affects the Blackburne-Peel Index measurement.Clinical RelevanceAs posterior tibial slope increases, the numerator of the Blackburne-Peel ratio decreases, and vice versa. This relationship can lead to incorrect assessment of patellar height. Objectively placing individuals into patella alta and baja categories may influence patient care and decision making.

The increase in posterior tibial slope provides a positive biomechanical effect in posterior-stabilized total knee arthroplasty.

This study aims to clarify the influence of the posterior tibial slope (PTS) on knee joint biomechanics after posterior-stabilized (PS) total knee arthroplasty (TKA) using a computer simulation. A validated TKA computational model was used to evaluate and quantify the effects of an increased PTS. In order to conduct a squat simulation, models with a - 3° to 15° PTS using increments of 3° were developed. Forces on the quadriceps and collateral ligament, a tibial posterior translation, contact point on a polyethylene (PE) insert, and contact stress on the patellofemoral (PF) joint and post in a PE insert were compared. The maximum force on the quadriceps and the PF contact stress decreased with increases in the PTS. The kinematics on the tibiofemoral (TF) joint translated in an increasingly posterior manner, and the medial and lateral contact points on a PE insert were located in posterior regions with increases in the PTS. Additionally, increases in the PTS decreased the force on the collateral ligament and increased the contact stress on the post in a PE insert. A higher force on the quadriceps is required when the PTS decreases with an equivalent flexion angle. A surgeon should be prudent in terms of determining the PTS because an excessive increase in the PTS may lead to the progressive loosening of the TF joint due to a reduction in collateral ligament tension and failure of the post in a PE insert. Thus, we support a more individualized approach of optimal PTS determination given the findings of the study.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction.

The number of primary anterior cruciate ligament (ACL) tears is rapidly increasing. In patients who wish to return to their preoperative level of function, specifically as it pertains to participation in sports, the gold standard of treatment following an ACL tear remains an anterior cruciate ligament (ACL) reconstruction. Despite a majority of good/excellent results following primary ACL reconstruction, there is a growing subset of patients with persistent or recurrent functional instability who require revision ACL reconstruction. Preoperative planning for revision ACL reconstruction requires a careful understanding of the root cause of ACL failure, including possible technical causes of primary ACL failure and the presence of combined knee pathology that was not addressed at the index ACL reconstruction. The decision to perform 2-stage revision ACL reconstruction is multifactorial and is reached by technical considerations that may make a 1-stage revision less optimal, including tunnel widening, arthrofibrosis, active infection, and others. Concomitant knee pathology such as meniscal deficiency, malalignment (including an increase in posterior tibial slope), chondral lesions, and other ligamentous laxity may also require a staged approach to treatment. This evidence-based review covers the indications for 2-stage revision ACL reconstruction, surgical techniques, evidence for and technique of bone grafting prior ACL tunnels, and outcomes of 2-stage revision stratified by initial cause of ACL reconstruction failure. With proper preoperative planning and an understanding of the cause of failure following the primary ACL reconstruction, revision ACL reconstruction can offer excellent outcomes in the motivated patient. [Orthopedics. 2016; 39(3):e456-e464.].

Effect of Wedge Insertion Angle on Posterior Tibial Slope in Medial Opening Wedge High Tibial Osteotomy.

Background:Medial opening wedge high tibial osteotomy (HTO) is a well-established surgery for medial compartment knee osteoarthritis (OA) wherein the lower extremity is realigned to shift the load distribution from the medial compartment of the knee to the lateral compartment. However, this surgery is known to affect the posterior tibial slope angle (PTSA), which could lead to abnormal knee kinematics and instability, and eventually to knee OA. Although PTSA control is as important as coronal realignment, few appropriate measurements for this parameter have been reported. The placement of a wedge spacer might have an effect on PTSA.Purpose:To elucidate the relationship between the PTSA and the direction of insertion of a wedge spacer.Study Design:Case series; Level of evidence, 4.Methods:This study assessed 43 knees from 34 patients who underwent medial opening wedge HTO for knee OA. Pre- and postoperative lateral radiographs of the knee as well as postoperative computed tomography scans were performed to evaluate the relationship among PTSA, wedge insertion angle (WIA), and opening gap ratio (distance of the anterior opening gap/distance of the posterior opening gap at the osteotomy site).Results:The PTSA significantly increased from 9.0° ± 2.8° preoperatively to 13.2° ± 4.1° postoperatively (P < .001), resulting in a mean ΔPTSA of 4.7° ± 4.5°. The mean opening gap ratio was 0.86 ± 0.11, and the mean WIA was 25.9° ± 8.4°. The WIA and opening gap ratio were both highly correlated with ΔPTSA (r = 0.71 and 0.72, respectively), implying that a smaller WIA or smaller gap ratio leads to less increase in posterior slope.Conclusion:The direction of wedge insertion is highly correlated with PTSA increase, which suggests that the PTSA can be controlled for by adjusting the direction of wedge insertion during surgery.Clinical Relevance:Study results suggest that it is possible to adjust the PTSA by controlling the WIA during surgery. Proper attention to WIA can avoid an iatrogenic increase in posterior tibial slope.

The Effect of Hinge Position on Posterior Tibial Slope in Medial Open-Wedge High Tibial Osteotomy

To evaluate whether hinge position affects the change in posterior tibial slope in medial open-wedge high tibial osteotomy (HTO). We retrospectively evaluated 19 knees from 17 patients who underwent medial open-wedge HTO by 3-dimensional computed tomography scan before and after surgery. A 3-dimensional image model was constructed by applying reverse-engineering software to the computed tomography DICOM (Digital Imaging and Communications in Medicine) files. The hinge axis (i.e., the position of the hinge compared with the anteroposterior axis on an axial view), posterior tibial slope, medial-proximal tibial angle, and gap ratio (i.e., the ratio of anterior gap to posterior gap in the opened wedge) were measured. The mean hinge axis was 4.92° ± 3.86°. Posterior tibial slope increased from 7.29° ± 2.56° preoperatively to 10.48° ± 3.01° postoperatively (P= .001). The mean medial-proximal tibial angle was 85.96° ± 1.97° preoperatively and 93.13° ± 3.17° postoperatively (P= .001). The mean gap ratio was 62.48% ± 7.26%. Linear regression analysis determined that the hinge axis (P= .0001) was a significant factor changing posterior tibial slope. Hinge position affected the change in posterior tibial slope in medial open-wedge HTO; in particular, a posterolateral hinge position led to an increase in posterior tibial slope. Level IV, therapeutic study.

Increase in posterior tibial slope would result in correction loss in frontal plane after medial open-wedge high tibial osteotomy

The purpose of this study was to clarify the causes of the increase in the posterior tibial slope during open-wedge high tibial osteotomy (HTO) and to investigate whether its changes influenced the correction angle in frontal plane. We retrospectively reviewed 20 patients (26 knees) treated with open-wedge HTO. They were divided into the following two groups. Group A consisted of the knees whose opening gaps were fixed using a spacer plate having the trapezoidal block with a 2° posterior slope. In Group B, anterior and posterior opening gaps were fixed separately. The posterior tibial slope and the hip-knee-ankle angle were measured based on CT data. The relationship between the correction rate in frontal plane and the changes of posterior tibial slope was investigated. Increase in the posterior tibial slope was 2.1 ± 2.5° in Group A and 0.2 ± 1.2° in Group B, which showed a statistical difference (P = 0.02). The difference between the hip-knee-ankle angles before and after operation was 5.2 ± 2.3° in Group A and 5.5 ± 2.5° in Group B. The correction rate was statistically correlated with the changes of posterior tibial slope (R = -0.55, P = 0.003). To avoid increase in the posterior tibial slope, the trapezoidal block with a only 2° posterior slope in a spacer plate was not sufficient, and it was necessary to fix anterior and posterior gaps separately. The correction angle in frontal plane had a trade-off relationship with the changes in posterior tibial slope. Thus, we thought that increase in the posterior tibial slope might result in correction loss. Therapeutic study, Retrospective comparative study, Level III.

Control of Posterior Tibial Slope and Patellar Height in Open-Wedge Valgus High Tibial Osteotomy

Background: Valgus-producing open-wedge high tibial osteotomy is an established treatment for varus malalignment and medial osteoarthritis, with reproducible results in the frontal plane. However, an undesirable but often accepted increase in posterior tibial slope and decrease in patellar height are still routinely seen. Purpose: To evaluate the influence of valgus open-wedge high tibial osteotomy on posterior tibial slope and patellar height when special techniques are used to minimize unwanted changes. Study Design: Case series; Level of evidence, 4. Methods: Twenty-five patients, 3 women and 22 men (mean age, 40.2 years), underwent valgus open-wedge high tibial osteotomy. Several technical steps were taken to prevent an increase in posterior tibial slope during the osteotomy. To minimize patellar height changes, the tibial tuberosity was left on either the proximal or distal fragment, depending on the desired patellofemoral effect. The medial and lateral posterior slope was measured using the proximal posterior cortex as a reference; the patellar height was assessed with the Caton-Deschamps Index and compared on preoperative and postoperative radiographs. Results: No significant posterior tibial slope changes were observed. Patellar height increased with both types of tibial tuberosity osteotomy. With the proximal osteotomy, the Caton-Deschamps Index increased from 0.95 to 0.97; with the distal osteotomy, it increased from 0.89 to 0.95. The change was not significant with either osteotomy. The posterior tibial slope did not change on the medial side, measuring 4.2 preoperatively and postoperatively. The lateral slope decreased from 5.4 to 5.1. There was no correlation between the correction in the coronal plane and the changes in the sagittal plane. Conclusion: Open-wedge high tibial osteotomy can be performed without significant changes in patellar height or posterior tibial slope if specific intraoperative methods are used to prevent their occurrence. Analysis and control of sagittal changes in valgus open-wedge high tibial osteotomy should reduce the incidence of unwanted changes in patellar height and posterior tibial slope.

A new fixation material for open-wedge tibial osteotomy for genu varum

Varus deformity of the knee is a determining factor in the development of osteoarthrosis of the medial compartment. Open wedge osteotomy corrects the deformity and has quickly become popular due to the fact that the surgical technique can be easily reproduced, it spares loss of bone tissue in the metaphysiary region, and it does not require muscle dissection, reducing the risk of lesion of the fibular nerve. The objective of this study was to evaluate the characteristics of a new fixation implant (Anthony-K plate - France Bloc S.A, CE n0499, ISO 9001, EN 46001), in terms of its clinical improvement, correction of the deformity, and slope alteration. Twenty adult patients with varus deformity were evaluated, and submitted to open wedge high tibial osteotomy using the Anthony plate, between October 2004 and November 2006. The varus deformity was corrected in all cases, and there was a significant increase in the Lysholm score. Correlation analysis has shown that the greater the preoperative varus deformity, the larger the opening wedge used. Also, the greater the initial posterior tibial slope, the larger the final posterior tibial slope (p=0.0168). There were no complications. The Anthony plate can be considered an alternative in the treatment of medial osteoarthrosis of the varus knee, enabling the correction of the deformity and improvement of the clinical picture. It occurs an increase in posterior tibial slope, similar to that observed with other fixation materials. More studies with the Anthony plate are necessary, after these encouraging results.

Closing or Opening Wedge High Tibial Osteotomy: Watch Out for the Slope

In recent years, there has been a renewed interest in high tibial osteotomies. The development of new instruments and better fixation devices has significantly simplified the surgical procedure. This technique frequently is used to correct alignment in the frontal plane. However, changes in the sagittal plane after high tibial osteotomy have not been appropriately investigated. Changes in posterior tibial slope may have a profound influence on biomechanics, kinetics, and kinematics of the knee joint. Laboratory and clinical studies suggest that an increase in posterior tibial slope decreases tibial sag and forces on the posterior cruciate ligament whereas decreases protect the anterior cruciate ligament. In addition, contact forces on the articular cartilage may be altered. These findings may be helpful for the treatment of knee instabilities and articular cartilage defects either as single treatment or in combination. Open wedge osteotomies increase the posterior tibial slope and are recommended for posterior cruciate ligament or posterolateral corner injuries. Closed wedge osteotomies can decrease posterior tibial slope and may be indicated in combination with anterior cruciate ligament reconstruction in a varus malalignment with existing medial compartment changes. This article provides an overview of posterior tibial slope changes introduced by high tibial osteotomy and its resultant changes on kinematics and kinetics of the knee joint.

Medial Opening Wedge Tibial Osteotomy and the Sagittal Plane

Background Altering the tibial slope in an anterior cruciate ligament–deficient knee has been shown to affect anterior-posterior tibial translation. The effects on articular contact pressure of altering tibial slope during a high tibial osteotomy are unknown. Hypotheses Performing an opening wedge osteotomy anterior to the midaxial line will increase tibial slope. Increasing tibial slope with a high tibial osteotomy in an anterior cruciate ligament–deficient knee redistributes tibiofemoral joint contact pressures onto the posterior tibial plateau. Study Design Controlled laboratory study. Methods Medial opening wedge high tibial osteotomies were performed, and a plate fixation with a known diameter inset was placed along the medial tibia in an anterior position and a posterior position on 9 cadaveric knees. Medial and lateral tibiofemoral contact pressures were measured at the resulting 2 different tibial slopes in both ligament-intact and ligament-deficient states using thin electronic sensors. Results Anterior plate application resulted in an increase in posterior tibial slope by an average of 6.6°(P <.001) compared with posterior plate placement. After medial opening wedge high tibial osteotomy, the mean peak lateral tibiofemoral contact pressure (3.4 MPa) was significantly greater (P=.002) than was the mean peak medial pressure (2.6 MPa). In ligament-intact specimens, altering the tibial slope did not significantly shift peak contact pressures. However, in ligament-deficient knees, increasing tibial slope by an average of 5.5° significantly redistributed the location of peak intra-articular pressure, shifting it posteriorly by 24% (P=.003). Conclusion Increasing tibial slope in anterior cruciate ligament–deficient knees with a high tibial osteotomy redistributes pressure into the posterior tibial plateau. Clinical Relevance In knees with chronic anterior cruciate ligament deficiency, posteromedial compartment degeneration is observed. Inadvertent redistribution of contact pressure into this area may be a cause of pain and premature clinical failure after medial opening wedge tibial osteotomy.

Anterior opening wedge osteotomy of the proximal tibia for anterior knee pain in idiopathic hyperextension knees

We analysed 20 patients with 24 knees affected by idiopathic genu recurvatum who were treated with an anterior opening wedge osteotomy of the proximal tibia because of anterior knee pain. We managed to attain full satisfaction in 83% of the patients with a mean follow-up of 7.4 years. The mean Hospital for Special Surgery score was 90.3 (range 70.5-99.5), and the mean Knee Society score score was 94.6 (70-100) for function and 87.7 (47-100) for pain. The mean Western Ontario and McMaster University Osteoarthritis Index score for knee function was 87.5 (42-100), for stiffness 82.8 (25-100) and for pain 87.3 (55-100). Radiographs showed a significant increase in posterior tibial slope of 9.4 deg and a significant decrease of patellar height according to the Blackburne-Peel method of 0.16 postoperatively. No cases of non-union, deep infection or compartment syndrome were seen. No osteoarthritic changes in the lateral or medial knee compartment were found with more than 5 years' follow-up in 16 patients with 19 affected knees. Three out of the four dissatisfied patients had a patella infera which led to patellofemoral complaints. One patient in the study underwent a secondary superior displacement of the patella with excellent results. We conclude that in a selected group of patients with idiopathic genu recurvatum and anterior knee pain an opening wedge osteotomy of the proximal tibia can be beneficial.