Change In Tibial Slope Research Articles

Radiological outcomes in a randomized trial comparing opening wedge and closing wedge techniques of high tibial osteotomy.

The aim of the present study was to examine changes in radiological variables in a prospective randomized study comparing opening wedge (OW) and closing wedge (CW) techniques of high tibial osteotomy (HTO). Our hypothesis was that there would be no differences in joint line angles or correction accuracy between the two groups, that patellar height would increase after CW HTO and decrease after OW HTO, and that leg length and posterior tibial slope would decrease after CW HTO and increase after OW HTO. Radiological data were collected from 70 patients participating in an ongoing prospective randomized clinical trial comparing OW and CW HTOs. Digital standing hip-knee-ankle (HKA) radiographs as well as lateral radiographs in 30° of flexion were obtained preoperatively and at 6months for each patient. Joint line angles, HKA angle, leg length, Insall-Salvati index, Miura-Kawamura index and posterior tibial slope were measured using medical planning software. The complete preoperative radiological examinations of the first 50 patients were used in a study of intra- and inter-rater reliability of the measurements. The mean posterior slope was reduced by 2.5° in CW HTO, whereas it remained unchanged in OW HTO (p<0.001). Mean leg length decreased 5.7mm in CW HTO and increased 3.1mm in OW HTO (p<0.001). Changes in joint line angles, patellar height indexes and the correction accuracy showed no significant differences comparing the two techniques. Frontal plane reliability measurement intra- and inter-rater intraclass correlation coefficient (ICC) varied from 0.81 to 0.99. Sagittal plane intra- and inter-rater ICC varied from 0.60 to 0.87. Posterior tibial slope intra- and inter-rater ICC showed the lowest values (0.70 and 0.60, respectively) corresponding to a smallest real difference of 4.5° and 5.5°, respectively. Posterior tibial slope and leg length changes were significantly different in CW compared to OW HTOs. We recommend that possible alterations in tibial slope and leg length are considered when the technique of HTO is to be chosen. Landmark-based medical planning software shows good reliability and can be used in preoperative planning and postoperative evaluations of HTOs. I.

Age-related Changes of Posterior Tibial Slope and Its Roles in Anterior Cruciate Ligament Injury.

Nearly all previous studies in posterior tibial slope (PTS) and anterior cruciate ligament (ACL) injuries ignored age-related changes, and the published data are inconsistent. The objective of this study was to reveal age-related changes of PTS and its roles in ACL injury. Data for 2618 lower limbs were included initially based on the availability of lateral radiographs and a suitable femoro-tibial angle. The final 1431 subjects were analyzed according to age, gender, side, and injury status. Student's t-tests, one-way analysis of variance, and curve fitting were used to analyze data. The PTS in males was greater than that in females in the 0-9 and 30-39-year-old groups, but this pattern reversed in the 40-49, 60-69, 70-79, and 80-89-year-old groups. The PTS was greater on the left side than on the right side in the 0-9, 10-19, 50-59, 60-69, and 80-89-year-old groups. The curve fitting for PTS demonstrated a trend of first decreasing and then increasing with aging. The PTS values differed significantly between knees with an ACL injury and those without in the 20-29, 30-39, and 40-49-year-old groups but not in the 50-59-year-old group. The PTS follows a trend of first decreasing and then increasing, and its role in ACL injury changes with advancing age. The higher PTS is only unrelated to the risk of ACL injury in age groups with a lower mean PTS value.

Increased Lateral Tibial Slope is a Risk Factor for Pediatric ACL Injury

Objectives:Recent research has asserted that increased posterior tibial slope measured on plain radiographs is associated with elevated risk of ACL rupture in adults. It is unclear, however, if tibial slope is also of significance in children and adolescents. The purpose of this case-control study was to 1) determine if alterations in posterior tibial slope are associated with ACL rupture in pediatric and adolescent athletes, and 2) to quantify changes in tibial slope by age.Methods:T2-weighted sagittal MRI scans of the knee were reviewed by three raters in a 1:1 sample of cases and controls, totaling 152 patients. Seventy-six skeletally immature patients with a complete non-contact ACL rupture were compared to an age- and gender-matched control group of 76 knees without ACL injury. The mean age of both groups was 14.8 +/- 1.3 years old and 46% of both groups were male. The medial and lateral compartments were each measured separately. All measurements were made using PACS software, employing a method similar to that which has been standardized in the adult literature. Our technique differed from previous studies in adults, though, in that the slope was measured on the cartilage surface, not the subchondral bone.Results:The mean posterior slope of the medial tibial plateau (MTS) was 5.4° ± 2.2° and 5.1° ± 2.3° (t-test; P=0.42) in the ACL-injured and control knees, respectively. The mean posterior slope of the lateral plateau (LTS) was 5.7° ± 2.4° in the ACL-injured knees and 3.4° ± 1.7° in the control knees (t-test; P<0.001) (Table 1). There was no difference in LTS between males and females (4.46° and 4.58°, P = 0.75). An interaction variable created by combining gender with LTS in a logistic regression model was not significant (P=0.12). Receiver operating characteristic (ROC) analysis of lateral tibial slope was used to determine a threshold value that might predict elevated risk of ACL injury. A cutoff of lateral posterior tibial slope >4° resulted in a sensitivity of 76% and a specificity of 75% for predicting ACL rupture in this cohort. Interrater reliability of tibial slope measurements was excellent (ICC=0.62 and 0.77 for the medial and lateral tibial plateaus, respectively). Spearman correlation analysis revealed that tibial slope decreased, or flattened, by 0.18° (P=0.028) and 0.21° (P=0.009) degrees per year as adolescents age.Conclusion:The biomechanical basis for an association between posterior tibial slope and ACL injury is well established in adults. To our knowledge, this is the first study that evaluates the association between tibial slope (as measured along the cartilage surface on MRI rather than subchondral bone on plain radiographs) and the risk of ACL rupture in a large adolescent cohort using a case-control design. Employing standard measurement techniques, the lateral tibial slope averaged 5.7° in ACL-injured knees and 3.4° in ACL-intact knees. A cutoff of >4° for the lateral posterior slope is 76% sensitive and 75% specific for predicting ACL rupture in this cohort of skeletally immature athletes. LTS did not influence the incidence of ACL injury differently between genders.

Increased Lateral Tibial Slope Is a Risk Factor for Pediatric Anterior Cruciate Ligament Injury

Background: Increased posterior tibial slope is associated with increased risk of anterior cruciate ligament (ACL) injury in adults. A similar association has not been rigorously examined in children and adolescents. Purpose: To determine whether alterations in posterior tibial slope are associated with ACL tears in pediatric and adolescent patients and to quantify changes in tibial slope by age. Study Design: Case-control study; Level of evidence, 3. Methods: Magnetic resonance imaging (MRI) studies of the knee were reviewed by 3 raters blinded to each other in a 1:1 sample of cases and age- and sex-matched controls. A total of 76 skeletally immature ACL-injured knees were compared with 76 knees without ACL injury; the mean age of the study population was 14.8 ± 1.3 years. The posterior slope of the articular surface of the medial tibial plateau and lateral tibial plateau was measured by use of a method similar to that used in previous studies in adult populations. The current study technique differed in that the slope was measured on the cartilage surface, not the subchondral bone. Comparisons between knees were made with t tests, and Spearman correlation analysis was used to assess changes in tibial slope with advancing age. Results: Increased slope of the lateral tibial plateau (LTS) was significantly increased in ACL-injured patients compared with controls (5.7° ± 2.4° vs 3.4° ± 1.7°; P < .001). There was no statistically significant difference in the slope of the medial tibial plateau (MTS) in the ACL-injured and control knees (5.4° ± 2.2° vs 5.1° ± 2.3°; P = .42). There was no difference in LTS between male and female patients (4.46° vs 4.58°; P = .75). Receiver operating characteristic (ROC) analysis of the LTS revealed that a posterior tibial slope cutoff of >4° resulted in a sensitivity of 76% and a specificity of 75% for predicting ACL tears in this cohort. Spearman correlation analysis revealed that MTS and LTS decreased, or flattened, by 0.31° (P = .028, correlation coefficient r = −0.18) and 0.37° (P = .009, correlation coefficient r = −0.21) per year, respectively, as adolescents age. Conclusion: The LTS was significantly associated with an increased risk of ACL injury in pediatric and adolescent patients. The MTS was not associated with risk of injury. Posterior slope was found to decrease, or flatten, with age. A cutoff of >4° for the posterior slope of the lateral compartment is 76% sensitive and 75% specific for predicting ACL injury in this cohort. The LTS did not influence the incidence of ACL injury differently between sexes.

Tibial slope and patellar height changes following high tibial osteotomy (a comparative study)

Improving the accuracy of high tibial osteotomy not only in the coronal plane but with considering it as a three dimension procedure can give better long term results in cases of medial compartment osteoarthritis associated with varus deformity and minimize the obstacles faced in future total knee replacement (TKR). Two different techniques of high tibial osteotomy: the opening wedge (OWO) and the hemicallotasis osteotomy (HCO) were compared clinically in a prospective randomized clinical trial that was held in Ain Shams University hospitals in the period from December 2010 to April 2013 on thirty knees of twenty-four patients suffering from medial compartment osteoarthritis associated with varus deformity. The patients were allocated randomly (single-blinded) in two groups; where fifteen knees of group (I) underwent high tibial osteotomy using the OWO technique, while those of group (II) underwent the procedure using the HCO technique. Two important parameters were compared; the posterior tibial slope in lateral radiographs using the anatomical proximal tibial axis and the patellar height using the CatonD to assess the accuracy of the procedure in the sagittal plane. OWO had proven lower accuracy than HCO as regard the change in tibial slope (P = 0.001 and 0.3 respectively), while both techniques preserved patellar height almost unchanged with optimizing the procedures’ techniques (P = 0.4 and 0.6 respectively). HCO technique for osteoarthritic knees associated with varus deformity can give more accurate results for the sagittal limb alignment and this may improve the long term results of the procedure and facilitate future TKR.

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.

Does proximal tibial osteotomy with a novel osteotomy system obtain coronal plane correction without affecting tibial slope and patellar height?

To determine changes in tibial slope, patellar height, and coronal plane alignment after medial opening wedge proximal tibial osteotomy (PTO) using a modern osteotomy system. Patients undergoing medial opening wedge PTO for any indication with follow-up until radiographic union were identified. Pre- and post-operative tibial slope (referenced off the anterior tibial cortex, proximal tibial anatomic axis, and posterior tibial cortex), patellar height (Caton-Deschamps, Blackburne-Peel, and Insall-Salvati indices), and coronal plane [mechanical axis and weight-bearing line (WBL) ratio] measurements were taken by two observers and compared. Review of 27 patients demonstrated unchanged tibial slope and slightly decreased patellar height post-operatively (Caton-Deschamps: -0.10 ± 0.09; Blackburne-Peel: -0.11 ± 0.10). Coronal plane measurements showed 6.4° ± 1.8° mean change in mechanical axis. Mean post-operative WBL ratio was significantly lower (51.6 ± 11.5 %) than mean goal WBL ratio (62.2 ± 2.5 %). Preoperative mechanical axis >6° varus and osteoarthritis alone as the surgical indication were risk factors for undercorrection >10 %. Medial opening wedge PTO using a recently developed instrumentation system was found to have no effect on tibial slope. Patellar height was decreased after osteotomy using this system, although clinical significance of these findings is unknown. Coronal plane undercorrection of 10.6 % of the target WBL ratio was seen in the group as a whole, although secondary analysis of these results indicated that patients with medial compartment osteoarthritis and/or preoperative mechanical axis of >6° varus accounted for the majority of the cases of undercorrection. Retrospective case series, Level IV.

High Tibial Valgus Osteotomy: Closing, Opening or Combined? Patellar Height as a Determining Factor

BackgroundAccording to the literature, closing and opening wedge high tibial valgus osteotomies can raise or lower the patella, and diffèrent methods of patella height measurement show similarly conflicting results. Clarification of this was thought to be important because there is much literature describing morbidity secondary to patella alta or patella infera (baja). Effects on tibial slope and patellar tendon length are not well delineated and the influence of sex and age is unknown.Questions/purposeA group of patients who underwent high tibial valgus osteotomy was investigated to determine how surgical technique influenced postoperative (1) patellar height and (2) tibial slope and patellar tendon length, and (3) whether age or gender independently influenced postoperative patellar height. To eliminate the often conflicting results seen when several ratio methods are used, patellar height was measured by one method, before and after surgery, shown previously to be reliable.MethodsPatellar height was measured on radiographs using the plateau-patella angle in a retrospective case series consisting of three cohorts: 18 patients with closing wedge osteotomies, 26 with opening wedge osteotomies, and 32 with combined osteotomies. The indication for surgery in all three cohorts was medial osteoarthritis with secondary varus. Before surgery there were no significant differences in patellar height, femorotibial angle, age, or gender among the three groups, and no patients were lost to followup during the 8-week study period after surgery. Seven of the 76 patients (9.2%), all in the opening wedge cohort, had concomitant ACL reconstruction at the time of the tibial osteotomy. No other surgery, except arthroscopy, was performed at the time of osteotomy. Patellar tendon length was assessed by the Insall-Salvati index and tibial slope by the angle between the posterior tibial cortex and the medial tibial joint line. Postoperative measurements were made between 6 and 8 weeks. The influence of sex and age was calculated using patellar height measurements made before any surgery.ResultsAll closing wedge osteotomies produced patellar ascent by an average of 13% (p < 0.001), all opening wedges produced descent by an average of 21% (p < 0.001), and the combined osteotomy mean showed minimal change (p = 0.0034). The absolute consistency of the changes and their direction allow suggested guidelines for selection of osteotomy type. There were only slight changes in tibial slope. A significant change in patellar tendon length was seen in seven knees of the opening wedge cohort that had concomitant ACL reconstruction. All had a mean reduction of the Insall-Salvati index of 0.05 (approximately 5%), p = 0.0002. New findings showed higher patellae in female and older patients, unrelated to the surgery.ConclusionsIf it is accepted that patella baja and patella alta should be avoided, then closing wedge osteotomies should be performed only when the patella is low riding, and opening wedge osteotomies should be done only for patients with preexisting patella alta. The combined osteotomy minimizes changes in patellar height. Patellar tendon contractures and tibial slope changes can be avoided. The plateau-patella angle should be measured preoperatively to help decide the type of osteotomy.Level of EvidenceLevel III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Closing Wedge and Opening Wedge High Tibial Osteotomy in the ACL Deficient Knee: A Comparison of Stability and Alignment

Objectives:Opening and closing wedge high tibial osteotomies for the treatment of medial compartment arthritis can lead to secondary intended and unintended changes in posterior tibial slope. The effect of slope neutralization using high tibial osteotomies in ACL deficient knees has not been fully defined. The purpose of this study was to quantify the changes in anterior tibial translation and rotational stability in the ACL deficient knee following mulitplanar high tibial osteotomies comparing opening wedge to closing wedge techniques.Methods:Anterior drawer, Lachman, and Pivot-shift tests were performed on hip-to-toe cadaveric specimens (n=16) and translation of the lateral and medial compartments was measured using Praxim navigation system. The ACL was then sectioned and stability testing repeated and compartment translation recorded. Half of the knees then underwent a closing wedge (LCW) high tibial osteotomy using a lateral titanium Tomofix plate and screws (n=8). The contralateral knees underwent an opening wedge (MOW) high tibial osteotomy using a medial titanium Tomofix plate and screws (n=8). The goal of both procedures was for an 8-10mm correction with maximal sagittal slope neutralization. Following this procedure, stability testing and translation measurements were once again performed. Pre and post-operative CT scans were performed to assess initial posterior tibial slope and slope correction, as well as coronal plane correction.Results:Sectioning the ACL resulted in a significant increase in anterior tibial translation (ATT) during Anterior drawer, Lachman, and Pivot shift testing (P < 0.05). In the ACL deficient knee the tibia translated on average an additional 2.1mm (±1.2) during Anterior drawer and 4.1mm (±2.1) during Lachman testing. Performing a LCW osteotomy demonstrated a significant decrease in ATT during Lachman testing that approached the native knee kinematics (P< 0.05), however, this decrease was not found during Anterior Drawer testing. ATT did not significantly improve following MOW osteotomy in the ACL deficient knee during any of the three tests. In fact, absolute translation values were unchanged following this procedure. The pivot shift was not significantly changed following either MOW or LCW. The mean Tibial Coronal alignment correction in the MOW group was 7.2º(±0.95) compared to 5.9º(±1.8) in the LCW group. Although the coronal correction was improved in the MOW, this difference did not reach significance (P = 0.08). The mean tibial slope neutralization achieved with a LCW was 7.1º(±1.8), which was significantly higher than 5.1 º(±0.9) found using MOW (P< 0.05).Conclusion:LCW HTO shows more reproducible slope neutralization than MOW and this benefits anterior translation during Lachman stability testing. When considering the use of an HTO in the setting of ACL deficiency, LCW should be considered given its favorable post-operative knee kinematics.

Factors influencing posterior tibial slope and tibial rotation in opening wedge high tibial osteotomy.

Opening wedge high tibial osteotomy (HTO) is an accepted treatment option for medial compartment knee osteoarthritis with associated varus lower limb axis in younger, more active patients. A concern with the use of this technique is that posterior tibial slope (PTS) and tibial rotation can be altered. We hypothesized that there is a tendency to increase the PTS and internal rotation of the distal tibia during the procedure and that certain intra-operative parameters may influence the amount of change that can be expected. A cadaveric model and surgical navigation system were used to evaluate the influence of certain intra-operative factors of the degree of PTS and tibial rotation change observed during medial opening HTO. Parameters evaluated included: degree of osteotomy opening, knee flexion angle, location of limb support (thigh versus foot), performance of a posteromedial release, the status of the lateral cortical hinge, and the degree of osteoarthritis present in the knee. Combining measurements of all specimens and parameters, a mean PTS increase of 2.7° ± 3.9° and a mean tibial internal rotation of 1.5° ± 2.9° were observed. Clinically, significant changes in tibial slope (>2°) occurred in 50.4 % of corrections, while significant changes in tibial rotation (>5°) occurred in only 11.9 % of corrections. Patients with significant osteoarthritis and concomitant flexion contracture, cases where large corrections were required, and procedures in which the lateral cortical hinge was disrupted were associated with increased PTS change. The other factors evaluated did not exert a significant influence of the degree of PTS change observed. Surgeons should be vigilant for possible PTS change, particularly in high-risk situations as outlined above. Routine use of an intra-operative measure of PTS is recommended to avoid inadvertent slope change.

Corrective tibial osteotomy in young adults using an intramedullary nail.

PurposeThe purpose of this study was to document results of a less invasive technique of open wedge proximal tibial osteotomy (PTO) for the varus knee in young adults using an intramedullary tibial nail.Materials and MethodsWe prospectively studied 24 knees in 16 young patients with varus knee deformity. The mean follow-up was 54 months (range, 36 to 107 months) and the mean age of patients at the time of operation was 25.8 years (range, 18 to 40 years). The open wedge PTO was performed below tibial tuberosity using a percutaneous multiple drill-hole technique. Conventional intramedullary tibial nail was used for fixation without bone graft. Radiographic evaluations were made using mechanical alignment (MA), posterior tibial slope angle, and Insall-Salvati ratio. Union time, loss of correction, implant failure, and associated complications were also investigated.ResultsThe mean MA was significantly changed from -9.7° preoperatively to 1.1° at the final follow-up (p<0.001). There was no significant change in the proximal tibial anatomy and patellar height. All patients achieved radiographic bony union at an average of 3.1 months without loss of correction. The only complication was knee pain due to nail prominence in 3 patients.ConclusionsRadiographic evaluation indicated that PTO using an intramedullary tibial nail leads to significant improvement in radiographic parameters without changes in posterior tibial slope or patellar height. We found that this technique could be a less invasive and effective alternative for correction of the varus knee in young adults.

Comparison of Stability and Slope Neutralization Between Closing Wedge and Opening Wedge High Tibial Osteotomy in the ACL Deficient Knee

Opening and closing wedge high tibial osteotomies for the treatment of medial compartment arthritis can lead to secondary intended and unintended changes in posterior tibial slope. The effect of slope neutralization using high tibial osteotomies in ACL deficient knees has not been fully defined. The purpose of this study was to quantify the changes in anterior tibial translation and rotational stability in the ACL deficient knee following mulitplanar high tibial osteotomies comparing opening wedge to closing wedge techniques.

Tibial slope and patellar height changes following high tibial osteotomy

Tibial slope and patellar height changes following high tibial osteotomy

Influence of the posterior tibial slope on the flexion gap in total knee arthroplasty

BackgroundAdjusting the joint gap length to be equal in both extension and flexion is an important issue in total knee arthroplasty (TKA). It is generally acknowledged that posterior tibial slope affects the flexion gap; however, the extent to which changes in the tibial slope angle directly affect the flexion gap remains unclear. This study aimed to clarify the influence of tibial slope changes on the flexion gap in cruciate-retaining (CR) or posterior-stabilizing (PS) TKA. MethodsThe flexion gap was measured using a tensor device with the femoral trial component in 20 cases each of CR- and PS-TKA. A wedge plate with a 5° inclination was placed on the tibial cut surface by switching its front–back direction to increase or decrease the tibial slope by 5°. The flexion gap after changing the tibial slope was compared to that of the neutral slope measured with a flat plate that had the same thickness as that of the wedge plate center. ResultsWhen the tibial slope decreased or increased by 5°, the flexion gap decreased or increased by 1.9±0.6mm or 1.8±0.4mm, respectively, with CR-TKA and 1.2±0.4mm or 1.1±0.3mm, respectively, with PS-TKA. ConclusionsThe influence of changing the tibial slope by 5° on the flexion gap was approximately 2mm with CR-TKA and 1mm with PS-TKA. Clinical relevanceThis information is useful when considering the effect of manipulating the tibial slope on the flexion gap when performing CR- or PS-TKA.

Restoring the anatomical tibial slope and limb axis may maximise post-operative flexion in posterior-stabilised total knee replacements

The optimal management of the tibial slope in achieving a high flexion angle in posterior-stabilised (PS) total knee replacement (TKR) is not well understood, and most studies evaluating the posterior tibial slope have been conducted on cruciate-retaining TKRs. We analysed pre- and post-operative tibial slope differences, pre- and post-operative coronal knee alignment and post-operative maximum flexion angle in 167 patients undergoing 209 TKRs. The mean pre-operative posterior tibial slope was 8.6° (1.3° to 17°) and post-operatively it was 8.0° (0.1° to 16.7°). Multiple linear regression analysis showed that the absolute difference between pre- and post-operative tibial slope (p < 0.001), post-operative coronal alignment (p = 0.02) and pre-operative range of movement (p < 0.001) predicted post-operative flexion. The variance of change in tibial slope became larger as the post-operative maximum flexion angle decreased. The odds ratio of having a post-operative flexion angle < 100° was 17.6 if the slope change was > 2°. Our data suggest that recreation of the anatomical tibial slope appears to improve maximum flexion after posterior-stabilised TKR, provided coronal alignment has been restored.

The effects of patellar tendon advancement on the immature proximal tibia

The aim of this study is to examine the short-term effects of patellar tendon advancement on the proximal tibial slope in the skeletally immature patient. A retrospective, non-randomized, comparative cohort design was used. Koshino indices and tibial slopes were assessed pre-operatively and post-operatively and compared with age- and sex-matched controls. Nine children with 17 patellar tendon advancements were analyzed for changes in Koshino indices. Of these 17 tibiae, radiographs on changes in tibial slope were available for 16 tibiae which were also compared with controls. Children aged <11years had a greater initial posterior tibial slope (69.8°±3.5°) than age-matched controls (80.3°±2.7°). A decrease in posterior slope was seen in these younger patients (average change 10.3°±4.8°) at an average of 1.6years of follow-up. Of the nine apophyses in children aged <11years of age, seven had undergone premature closure. Patellar tendon advancement appears to have an unreported effect on the proximal tibial growth in the young patient (<11years old). These patients appear to be susceptible to apophyseal closure, resulting in subsequent loss of posterior tibial slope. Surgeons should be aware of this effect and monitor younger patients with radiographs if performing this procedure.

Clinical Results Associated with Changes of Posterior Tibial Slope in Total Knee Arthroplasty

PurposeThe purpose of this retrospective study is to investigate the effect of posterior tibial slope (PTS) on clinical results in total knee replacement arthroplasty (TKA).Materials and MethodsWe analyzed 801 knees in 768 patients who underwent TKA using a cruciate-retaining prosthesis for osteoarthritis from July 2003 to July 2009. PTS was measured on simple X-ray films and patients were divided into 5 groups, according to the change in PTS that was calculated by subtracting the preoperative from the postoperative PTS: group 1, >3°; group 2, 3° to 1°; group 3, 1° to -1°; group 4, -1° to -3°; and group 5, <-3°. We analyzed the correlations between the change in PTS and clinical results, such as Knee Society knee score, Knee Society functional score, Feller patella score, Kujala score, visual analog scale score, range of motion, and complications.ResultsThere was no statistically significant intergroup difference; however, Feller patella score and Kujala score were significantly different in groups 2 and 3. There were no complications, such as progressive loosening of implants, fractures of polyethylene inserts and wears.ConclusionsClinically meaningful improvement was observed in all patients after TKA. Groups 2 and 3 (3° to -1°) showed significant improvement compared to the other groups.

Comparable Maintenance of Tibial Slope in Two High Tibial Osteotomy Techniques

Objectives:High tibial osteotomies (HTO) are commonly performed to correct coronal malalignment in young, active patients who have concomitant cartilage lesions and/or cruciate ligament insufficiency. An unintended change of native tibial slope can negatively affect both the strain on reconstructed cruciate ligaments and the contact forces on cartilage. Therefore, one of the goals when performing an HTO is to minimize any change in posterior tibial slope. This study was designed to determine if there is a time zero difference in the maintenance of native tibial slope when performing valgus producing opening wedge HTOs using two distinct surgical techniques and fixation devices.Methods:Controlled Laboratory Study. Experienced surgeons performed valgus producing opening wedge HTOs in 24 matched paired cadaveric specimens using free hand (FH, n=12) and biplanar cutting jig (Jig, n=12) techniques. Digital fluoroscopy was used to capture anteroposterior and lateral images in all specimens, and the angle of posterior tibial slope (TS) was measured using digital software (NIH image; Bethesda, MD) in a manner blinded for technique and fixation.Results:There was good to excellent intra- and inter-observer reliability with the measurement technique using a Model 3, k, intra-class correlation coefficient (ICC). Both observers’ measurements passed tests for homogeneity (p=0.07, and p=0.12). There was no significant change in the maintenance of tibial slope between JIG and FH groups for observer 1 [JIG = 2.40° (SD = 1.3°) FH= 2.95° (SD=2.89°), p = 0.55] or observer 2 [JIG = 2.32° (SD = 2.5°) FH = 3.14° (SD=3.3°), p = 0.49].Conclusion:When performing a valgus producing opening wedge HTO, neither the cutting jig nor the free hand technique maintained native posterior tibial slope. Both techniques increased posterior tibial slope by an average of 2-3° with no significant difference between the groups. This change in posterior tibial slope is consistent with previously reported values in the literature.

Patellar height modification after high tibial osteotomy by either medial opening-wedge or lateral closing-wedge osteotomies

High valgus tibial osteotomy is used to treat medial femoro-tibial osteoarthritis. Changes in patellar height due to high valgus tibial osteotomy can cause technical difficulties during subsequent knee arthroplasty. The primary objective of this study was to assess the hypothesis that patellar height decreases after opening-wedge osteotomy and increases after closing-wedge osteotomy. The secondary objective was to assess whether frontal axis correction and tibial slope modification correlated with patellar height changes. A multicentre, prospective, comparative, observational, non-randomised study was conducted in consecutive patients undergoing isolated high valgus tibial osteotomy according to standard practice in each of the ten study centres. Patellar height was assessed based on the Caton-Deschamps index. Of 321 included patients, 224 underwent opening-wedge and 97 closing-wedge osteotomy. Patellar height did not change significantly after closing-wedge osteotomy (1.07 ± 0.2 pre-operatively and 1.0 ± 0.19 postoperatively). Patellar height decreased significantly after opening-wedge osteotomy (from 0.98 ± 0.19 to 0.88 ± 0.21, p < 0.0001, mean decrease 9 ± 22%). Patellar height decreased by more than 20% in 49 (28%) patients after opening-wedge osteotomy. The patellar height decrease after opening-wedge osteotomy correlated significantly with axis correction magnitude and tibial slope change. Our results support routine baseline measurement of patellar height before high valgus tibial osteotomy and posterior positioning of the opening wedge to limit the tibial slope change in patients requiring major axis correction by opening-wedge osteotomy. Prospective cohort study, Level II.

Different changes in slope between the medial and lateral tibial plateau after open-wedge high tibial osteotomy

In contrast to radiographic measurements, MRI provides multiple slices of the knee joint in the sagittal plane, making it possible to assess the medial and lateral tibial slope separately. The purpose of this study is to investigate the effect of medial open-wedge high tibial osteotomy (MOWHTO) on bony and meniscal slope in the medial and lateral tibiofemoral compartments. It was hypothesised that greater changes on the medial tibial plateau would be observed compared with the lateral one. A retrospective analysis of prospectively collected data was performed on pre- and post-operative MRIs from 21 patients (17 men and 4 women; age 52±9years). Inclusion criteria were varus alignment, medial compartment osteoarthritis and election for a primary MOWHTO. Each patient had a preoperative and a post-operative high-resolution MRI (3Tesla, Magnetom Trio, Siemens AG) at an average follow-up of 2.1years. A previously published method was used to measure bony and meniscal slope for each compartment. The difference between pre- and post-operative tibial slope for both compartments was calculated and associated with the amount of frontal correction. There was a significant increase in bony tibial slope in both compartments following MOWHTO. When a change in bony tibial slope was detected in an individual patient, the change was larger in the medial compartment, with the average change also significantly greater (p<0.01) in the medial compartment (2.4°±1.3°) compared with the lateral compartment (0.9°±1.1°). There was also a significant increase (p<0.01) in the lateral tibial meniscal slope of 0.9°±1.4°, which was equivalent to the change in the bony lateral slope. The amount of frontal correction was not significantly associated with the amount of change in slope. The results suggest that the modification of the bony slope is larger in the medial compartment after MOWHTO, which is likely related to the location of the hinge on the lateral tibial cortex. These findings suggest that consideration of the medial and lateral tibial slope intra-operatively could be important to identify the optimal location of the hinge. However, further studies are required before recommending any modification to the surgical technique, as the potential clinical consequences of tibial slope alterations remain unknown. IV.