Postoperative Posterior Tibial Slope Research Articles

Factors Causing Unintended Sagittal and Axial Alignment Changes in High Tibial Osteotomy: Comparative 3-Dimensional Analysis of Simulation and Actual Surgery

Background: Unintended secondary changes in the posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open-wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSIs), it is essential to reproduce the PTS and TTA that were planned in simulations. Purpose: To analyze the factors causing unintended sagittal and axial alignment changes after MOWHTO. Study Design: Case series; Level of evidence, 4. Methods: Overall, 63 patients (70 knees) who underwent MOWHTO using a PSI between June 2020 and June 2023 were retrospectively reviewed. Preoperative and postoperative computed tomography scans were 3-dimensionally reconstructed. Simulated osteotomy was performed so that the weightbearing line could pass through the target point. A PSI gapper was 3-dimensionally printed to fit the posteromedial corner of the osteotomy gap in the simulated HTO model. After MOWHTO using the PSI gapper, the actual postoperative model was compared with the preoperative or simulation model. This assessment included PTS, TTA, hinge axis, and osteotomy-related parameters. Cortical breakage around the lateral hinge was evaluated to assess stability. Results: The mean PTS and TTA did not change in the simulation. However, significant changes were observed in the actual postoperative PTS and TTA (change, –2.4°± 2.2° and −3.9°± 4.7°, respectively). The PTS was reduced, while the TTA decreased with internal rotation of the distal fragment. The difference in the axial hinge axis angle (AHA) between the simulation and actual surgery was the factor most correlated with the difference in the PTS (r = 0.625; P < .001). In regression analysis, the difference in the AHA was the only factor associated with the difference in the PTS (β = 0.558; P = .001), and there were no factors that showed any significant associations with the difference in the TTA. In subgroup analyses for the change in the TTA, the correction angle and anterior osteotomy angle were significantly higher in the more internal rotation group (P = .023 and P = .010, respectively). The TTA change was significantly higher in the unstable group with lateral cortical breakage (P = .018). The unstable group was more likely to show an internal rotation of ≥5° (odds ratio, 5.0; P = .007). Conclusion: The AHA was associated with a difference in the PTS between the simulation and actual surgery. The change in the TTA was caused by a combination of multiple factors, such as a large correction angle and anterior osteotomy angle, but mainly by instability of the lateral cortical hinge.

Comparison of Alignment Accuracy and Clinical Outcomes between a CT-Based, Saw Cutting Robotic System and a CT-Free, Jig-guided Robotic System for Total Knee Arthroplasty.

The different cutting mode of robot-assisted TKAs may influence the accuracy of alignment. The purpose of this study was to compare alignment accuracy and early clinical outcomes between a CT-based, saw cutting robotic system (MAKO) and a CT-free, jig-guided robotic system (ROSA) for total knee arthroplasty (TKA). A total of 20 MAKO TKAs and 20 ROSA TKAs from June 2021 to June 2022 were retrospectively analyzed. Differences in the postoperative hip-knee-ankle (HKA) angle, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior tibial slope (PTS) and 3° outlier frequency of the HKA, LDFA, MPTA and PTS were studied at 3 months and 1 year of follow-up. The operative time and total blood loss (TBL) were compared between these two groups. Clinical outcomes at 1 year after surgery, including range of motion (ROM), Western Ontario McMaster University Osteoarthritis Index (WOMAC) score, and Knee Society Score-2011 (KSS-2011), were also compared between these two groups. The baseline characteristics of the two groups were comparable. There were no significant differences in the mean deviations of postoperative HKA, LDFA, MPTA or PTS between the two groups at 3 months or 1 year (all ps > 0.05). Moreover, there was no significant difference in the percentage of 3° outliers for HKA, LDFA, MPTA, or PTS between the two groups at 3-month or 1-year follow-up (all ps > 0.05). The mean operation time of MAKO was longer than that of ROSA (112.7 ± 12.8 min vs 94.8 ± 23.0 min, p = 0.001), but the mean TBL (1356.7 ± 648.5 mL vs 1384.5 ± 676.3 mL) and transfusion rate (15.0% vs 5.0%) were not significantly different between the two groups (all ps > 0.05). No significant differences were found in postoperative ROM, WOMAC score or KSS score at 1 year (all ps > 0.05). The MAKO and ROSA had similar accuracy and precision in TKA alignment. The clinical outcomes at 1 year after surgery were also comparable.

Accurate surgical posterior tibial slope alteration can be achieved in total knee arthroplasty regardless of surgeon skill level or local soft tissue thickness-A retrospective radiograph-based study.

To retrospectively report on the impact of local soft tissue thickness and surgeon skill level on the accuracy of surgical posterior tibial slope (PTS) alteration achieved in patients undergoing total knee arthroplasty (TKA) utilising lateral knee radiographs. Pre- and postoperative radiographs of 82 patients undergoing primary TKA using conventional mechanical alignment technique were measured by two observers and subjected to quality criteria for accurate measurement of the PTS. All patients underwent a standardised surgical approach for PTS alteration: cruciate-retaining (CR) cases with preoperative PTS ≤ 10° were set for reconstruction of the preoperative PTS. Cases indicated for posterior-stabilised (PS) design and/or with a preoperative PTS > 10° were set for 3° of postoperative PTS. Pretibial subcutaneous fat (PSF) and surgeon skill level were analysed for their predictive quality regarding the accuracy of surgical PTS alteration achieved. The overall mean postoperative PTS was significantly lower than the preoperative values (6.2°, SD 2.7 vs. 7.7°, SD 3.2; p = 0.002103). Neither local soft tissue thickness, namely PSF, nor surgeon skill level was found to be a predictor of the accuracy of surgical PTS alteration achieved. Among cases set for PTS reconstruction, 25.9% and 42.6% achieved a postoperative PTS within ±1° and ±2° of preoperative values, respectively. In patients with a PTS > 10° or those indicated for PS design, slope reduction was achieved with a mean postoperative PTS of 6.5°. Furthermore, 14.3% and 32.1% of cases were within ±1° and ±2° of 3, respectively. This study demonstrates that accurate surgical alteration of the PTS is possible in TKA regardless of local knee soft tissue thickness or surgeon skill level. This proves the clinical feasibility of both targeted reduction as well as reconstruction of the PTS in TKA. Level III, retrospective cohort study.

Clinical and radiological results of high tibial of osteotomy over the age of 65 are comparable to that of under 55 at minimum 2-year follow-up: a propensity score matched analysis

PurposeThe results of medial open-wedge high tibial osteotomy (MOWHTO) according to age is inconclusive. This study aimed to compare the clinical outcomes and failure of MOWHTO in patients < 55 years and > 65 years.MethodsConsecutive patients who underwent MOWHTO from July 2009 to August 2020 were retrospectively analyzed. 205 patients were considered for analysis. A 1-to-1 propensity score matched analysis to assess clinical outcomes scores including International Knee Documentation Committee (IKDC) subjective score and Lysholm score, radiologic outcomes, complication, and Total Knee Arthroplasty (TKA) conversion between patients > 65 years and patients < 55 years was performed. Radiologic outcomes included Hip-Knee-Ankle (HKA) angle, Weight Bearing Line ratio (WBLR), posterior tibial slope (PTS), and Insall-Salvati (IS) ratio before and after surgery.ResultsThe follow-up period was 50.4 months in patients > 65 years and 55.3 months in patients < 55 years. There was no significant difference in the preoperative and postoperative HKA angle, WBLR, PTS, IS ratio, IKDC score and Lysholm score between the two groups. The arthroscopic evaluation of cartilage did not show any statistically significant differences between the two groups. Regarding Minimal clinically important differences (MCID), in the 26% of the older group exceeded MCID of IKDC score; 45% of the older group exceeded MCID of Lysholm score. In the younger group, 24% exceeded MCID of IKDC score and 35% exceeded MCID of Lysholm score. In older group, there were 7 (11.3%) cases of TKA conversion while no TKA conversion was recorded in the younger group. (P = 0.007) The average time to TKA conversion was 67 months. (42 months to 90 months) Kaplan–Meier analysis revealed that the survival rate was 95.2% at 4 years in the older group.ConclusionSimilar clinical results were obtained in patients over 65 years of age that were eligible for MOWHTO at minimum 2-year follow-up as in patients under 55 years of age. MOWHTO may be a viable option in older patients if proper indications are met. However, the risk of TKA conversion must be considered preoperatively and discussed with patients.Study Design: Cohort study; Level of evidence, 3.

Patient-specific cutting guides increase accuracy of medial opening wedge high tibial osteotomy procedure: A retrospective case-control study.

To compare the accuracy of patient-specific guides (PSCG) to the standard technique in medial open-wedge high tibial osteotomy (OWHTO). Secondary objectives were to evaluate factors that could influence accuracy and to compare the complication rate and operating time for both procedures. A retrospective analysis of prospective collected data was performed. Between March 2011 and May 2018, 49 patients with isolated medial knee osteoarthritis who were operated for OWHTO using PSCG and 38 patients using the standard technique were included. Preoperative and postoperative deformities were evaluated on long leg radiographs by measuring the mechanical medial proximal tibial angle, mechanical lateral distal femoral angle, hip knee ankle angle (HKA), and joint line convergence angle. Pre- and postoperative posterior tibial slope was also evaluated. Accuracy was evaluated by analysing the difference between the preoperative planned and the actual postoperative HKA. Operating time and complication rate were also recorded in both groups. The mean preoperative HKA was 173.4° (±3.1°) in the PSCG group and 173.3° (±2.4°) in the standard group (p = 0.8416). Mean planned HKA were 182.8° (±1.1°) and 184.0° (±0°) respectively for the PSCG and the standard group. Mean postoperative HKA were 181.9° (±1.9°) and 182.6° (±3.1°) respectively for the PSCG and the standard group. An accuracy of ±2° in the HKA was achieved in 44 (90%) in the PSCG group and 24 (65%) in the standard group (p = 0.006). The probability of achieving a HKA accuracy was four times higher for patients in the PSCG group (odds ratio [OR] = 4.06, [1.1; 15.3], p = 0.038). Also, higher preoperative Ahlback grade was associated with precision, all other parameters being equal (OR = 4.2, [0.13; 0.97], p = 0.04). In this study, the PSCG technique was significantly more accurate for achieving the planned HKA in OWHTO. Complication rates and operating times were comparable between groups. Level IV, case-control study.

Systematic Review of Clinical Outcomes After Proximal Tibia Anterior Closing-Wedge Osteotomy With ACL Reconstruction.

While increased posterior tibial slope (PTS) is an important risk factor for failure after anterior cruciate ligament (ACL) reconstruction, controversy exists regarding indications and outcomes of proximal tibia anterior closing-wedge osteotomy (ACWO) with concomitant ACL reconstruction in patients with ACL tears. To assess clinical outcomes after combined ACL reconstruction and proximal tibia ACWO. Systematic review; Level of evidence, 4. In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, we performed a systematic review of the existing literature on ACWO and ACL reconstruction using PubMed (MEDLINE), Cochrane Library, Scopus, and Embase. The search phrases included "anterior closing wedge osteotomy,""anterior closing wedge tibial osteotomy,""anterior closing wedge proximal tibial osteotomy,""anterior cruciate ligament," and "revision anterior cruciate ligament." Non-English publications and single-patient case reports were excluded. Extracted data included study details, patient demographics, patient-reported outcomes (PROs), clinical outcomes, radiographic outcomes, complications, and return-to-sport (RTS) rates. A total of 6 studies with 110 patients (110 knees) were included. Two-stage ACWO and ACL reconstruction was reported in 2 studies of 78 patients (71%), while a single-stage technique was reported in 4 studies of 32 patients (29%). ACWO was performed in the setting of primary ACL tear in 23 patients (21%) and in recurrent ACL tear in 87 patients (79%). Patients demonstrated postoperative improvements in Lysholm, pivot-shift test, and side-to-side difference in anterior tibial translation. After ACWO, all studies reported mean postoperative PTS of <10° (range, 4.4°-9.2°). Of patients with available RTS data (n = 43), the same-level RTS rate ranged from 65% to 100%. A two-stage procedure reported in 1 study had a lower RTS rate (n = 13 of 20 [65%]) than that of 2 studies with single-stage procedure (n = 4 of 5 [80%] and n = 18 of 18 [100%]). The overall complication rate was 0.9% to 1.3%, and there were no reported ACL retears. The current evidence, which is constrained by the quantity and quality of studies, showed that ACWO with single- or two-stage ACL reconstruction in patients with ACL insufficiency and increased PTS was associated with significant improvements in PROs and high RTS rates.

Artificial intelligence-based detection of posterior tibial slope on X-ray images of unicompartmental knee arthroplasty patients

ObjectiveThis paper aims to improve the assessment of the outcomes of unicompartmental knee arthroplasty (UKA) from the angle of posterior tibial slope (PTS) on X-Ray images, using the artificial intelligence (AI) tool of RetinaNet. MethodsFirstly, RetinaNet was trained and tested on patients who underwent unilateral knee replacement surgery in our hospital due to osteoarthritis in the medial compartment of either their left or right knee between July 2018 and July 2022. The trained network was applied to detect the region of interest (ROI) on the pre- and postoperative X-ray images of each subject. Next, the subjects were divided into three groups according to the PTS changes measured by the trained RetinaNet. Furthermore, the surgical effect of UKA was evaluated from multiple angles, including pre- and postoperative PTSs, knee joint mobility (KJM) values, the Hospital for Special Surgery (HSS) scores, as well as the Joint Replacement Forgetting Index (JRFI). ResultsAfter training, the RetinaNet achieved an astounding accuracy level, with the Cronbach's alpha value 0.864 (95%CI 0.762–0.915). There significant differences were found between Group II and Group I (P = 0.017) and Group III and Group I (P = 0.032); in terms of JRFI, Group II had a significantly better than Group I (P = 0.011) and Group III (P = 0.037). ConclusionsThe trained RetinaNet is suitable for assisting with PTS measurements in X-ray images; the PTS variation through UKA should be controlled within 2° to ensure the best possible surgical effect.

Posterior slope of the tibial plateau in cohort of Omani patients undergoing total knee arthroplasty

Objectives: Posterior tibial slope (PTS) is an important factor in restoring joint biomechanics after total knee arthroplasty (TKA). Given ethnic variation and the lack of recorded values for PTS, this study aimed to report PTS in a cohort of Omani patients (Arab ethnicity). Methods: This retrospective study included all Omani patients who underwent TKA in a specialized center between May 2017 and March 2020. Patients with revision TKA, extra-articular deformity, and tibial defects necessitating bony build-up and traumatic indications were excluded. Data collected include age, gender, and pre-and post-operative PTS. Results: A total of 128 patients were included in the study, 94 (73.4%) were female and 34 (26.6%) were male. The mean age of the patients was 65.16 years, standard deviation (SD) 8.47 (Maximum 87–Minimum 43). The mean pre-operative PTS was 10.6° (SD 3.65), whereas most current TKA designs aim for a 5–6° posterior slope. We found no correlation between PTS value and age or gender (P &gt; 0.05). Conclusion: Given the higher PTS angle found in this study, which is consistent with those reported in the literature for Asian and Arab populations. This study indicates the importance of examining PTS variation within the population served. The proximal tibia shape and cutting angle can be varied to avoid any discrepancy in PTS after implantation.

The effect of posterior tibial slope on anteroposterior stability in posterior cruciate retaining total knee arthroplasty

BackgroundIt has been suggested that the posterior tibial slope (PTS) plays an important role in increasing the anteroposterior stability following total knee arthroplasty. Although the relationship between the PTS and the flexion range has been investigated many times, studies on the relationship between PTS and anterior-posterior stability are limited. The primary aim of this study was to investigate the relationship and effects of PTS on anteroposterior stability in posterior cruciate retainer total knee arthroplasty.Methods154 primary TKAs were identified retrospectively to analyze the any association between PTS and anteroposterior laxity following posterior cruciate-retaining total knee arthroplasty in the overall study populations. Anteroposterior displacement was measured at the final follow-up based on the following two procedures: KT-1000 arthrometer and sagittal drawer radiographic images. In addition, the relationship between PTS and functional scores-ROM was examined.ResultsThere was no correlation between patients’ posterior tibial slope and postoperative VAS (r: -0.060, p:0.544), WOMAC (r:0.037, p:0.709), KSS (r: -0.073, p:0.455). In addition, there was no significant correlation between postoperative knee ROM and postoperative PTS (r:0.159, p:0.106). Moreover, no correlation was found between KT-1000 arthrometer and 20 degrees AP translation with PTS. There was a negative correlation between PTS and 70 degrees AP translation (r: -0.281, p:0.008).ConclusionsThis study aimed to clarify the association between instability and AP laxity in flexion of implanted knees, and to determine what degree of AP laxity results of instability. A fundamental finding of this study was that; the optimum TS angle to increase anterior-posterior stability after total knee arthroplasty is between ≥ 4 to < 6 degrees, we also proved that there is no relationship between stability and patient satisfaction.

In slope-changing osteotomy one millimeter is not one degree: results of an artificial intelligence-automated software analysis.

Anterior closing wedge osteotomies (ACWO) are performed in revision anterior cruciate ligament (ACL) surgery to correct an excessive posterior tibial slope (PTS). With the help of automated planning software, this study investigates the assumption that 1mm of wedge height gives 1° of slope correction (1:1). Fifty patients underwent ACWO, with the wedge height calculated using the 1:1 formula. Pre- and postosteotomy PTS were measured manually, and the achieved post-operative PTS was compared with the target PTS of 5.3° ± 1.9. The X-ray analysis was repeated virtually with the automated software, which also recommended a resection height. These parameters were then compared with the manually obtained parameters. Using a 1:1 formula, wedge heights of 8.5mm ± 2.3 was resected to achieve a PTS of 4.2° ± 0.32. This showed an overcorrection of 1.6° ± 0.8 from the target slope. This was consistent with the data from the automated software, which recommended a lower wedge height of 7.7mm ± 2.9. In trans-tubercle ACW, using a wedge height (mm) to slope correction (°) ratio of 1:1 can lead to slight over-correction. Automated software planning is useful for planning correction osteotomies in the sagittal plane.

Influence of posterior tibial slope on postoperative outcomes after postero-stabilized and condylar-stabilized total knee arthroplasty.

To compare clinical outcomes and surgical times of two different types of total knee arthroplasty(TKA), postero-stabilized(PS) and condylar-stabilized(CS), in relation to posterior tibial slope(PTS) values and the deviation of these values from the surgical technique. 168 patients undergoing TKA surgery between 2016 and 2020 met our inclusion criteria. For each case, gender, age at surgery, operating time, type of implant and preoperative PTS(preop-PTS) and postoperative PTS(postop-PTS) measurements were collected; difference(∆PTS) between preop-PTS and postop-PTS was also calculated. Short Form 12 Mental and Physical scores(SF-12M and P) and functional Knee Society Score(fKSS) were collected preoperatively and at a minimum of 12months postoperatively. Four subgroups were thus created in relation to PS or CS system and postop-PTS value(≤ 5°and > 5°). Of the 168 patients, 96 had a PS system and 72 CS system. Performing a CS-TKA took less time than a PS-TKA(p < 0.05). SF-12P showed better results(p < 0.05) in CS-TKA group than PS-TKA, probably because of the younger age of CS-TKA patients(p < 0.05). In the PS > 5° all examined postoperative scores were better(p < 0.05) than PS ≤ 5°, while only fKSS was better(p < 0.05) in CS > 5° than CS ≤ 5°. No significant difference(p > 0.05) in terms of postoperative outcomes between the PS > 5° and CS > 5° was noted, whereas only SF-12P was better in the CS ≤ 5° compared with PS ≤ 5°. Highest values of SF-12M and fKSS were obtained in the PS ≤ 5°, in which postop-PTS was closer to technique. When performing a PS-TKA, the best result was obtained with a postop-PTS > 5°, but comparable outcomes between the two systems were evident with postop-PTS > 5°. It is crucial to come as close as possible to the indications reported in surgical technique regardless ∆PTS.

Slope-decreasing anterior closing wedge proximal tibial osteotomies using the freehand technique are accurate to within 2̊

IntroductionAnterior cruciate ligament (ACL) reconstruction requires a detailed analysis of the posterior tibial slope (PTS) as excessive values may cause the reconstruction to fail and require a slope-decreasing anterior closing wedge tibial osteotomy combined with revision of the failed ACL reconstruction. The main purpose of this study was to assess the accuracy of correction after slope-decreasing anterior closing wedge tibial osteotomy in cases of chronic anterior instability caused by ACL rerupture. Materials and methodsThis single-center retrospective study included 19 patients (20 knees) operated on by slope-decreasing anterior closing wedge tibial osteotomy combined with a second revision ACL reconstruction. The mean age was 22.4±3.3 years and the mean follow-up was 12.7±4.4 months. The preoperative planning was based on lateral calibrated X-rays of the entire tibia. The height of the closing wedge, which corresponded to the base of the osteotomy, was measured in millimeters. The procedure was performed using the freehand technique. The accuracy of the correction was defined as the difference between the desired preoperative PTS and the postoperative PTS achieved. An inter- and intraobserver analysis was performed. ResultsThe mean preoperative PTS was 13.9±2̊ and the mean postoperative PTS was 4.0±1.7̊. The mean PTS correction was 10.1±2.1̊ with a planned target of 5.4±1.8̊. The accuracy obtained between the planned target and the postoperative corrections was 1.7±1.1̊. The regression analysis showed that the accuracy of the PTS correction was not influenced by the patient's age, BMI, excessive preoperative PTS, or degree of correction achieved (p>0.05). ConclusionSlope-decreasing anterior closing wedge tibial osteotomies performed using the freehand technique for ACL graft rerupture can correct an excessive PTS within 2̊ of the planned slope correction. This accuracy is not determined by demographic factors, excessive preoperative PTS or degree of correction achieved. Level of evidenceIV; retrospective cohort study.

Referencing the Tibial Plateau With a Probe Improves the Accuracy of the Posterior Slope in Medial Unicompartmental Knee Arthroplasty.

BackgroundThere is currently no consensus on intraoperative references for determining the posterior tibial slope (PTS) in medial unicompartmental knee arthroplasty (UKA). The medial tibial plateau could serve as a direct reference for determining the native PTS through the placement of a hook probe in the anteroposterior direction of the medial tibial plateau. This study aimed to examine the accuracy of this new referencing method.MethodsWe consecutively performed 55 medial UKAs using our new method (study group), and the preoperative and postoperative PTS on lateral knee radiographs were examined. These outcomes were then compared with those of consecutive 50 medial UKAs performed using the conventional method (control group), which immediately preceded the start of the use of the new method.ResultsThe correlation coefficient between the preoperative and postoperative PTS of the study group was larger than that of the control group (0.887 and 0.482, respectively). The mean implantation error of the PTS in the study group was smaller than that of the control group (−1.1° ± 1.3° and −3.0° ± 3.2°, respectively; P < .0001). The percentages of knees within 2° of implantation error were 73% and 34% in the study and control groups, respectively (P < .0001). The root mean square errors in the study and control groups were 1.7° and 4.3°, respectively.ConclusionsThe direct referencing method with a probe can significantly improve the accuracy of tibial sagittal alignment.

No influence of posterior tibial slope change on outcomes after cruciate-retaining total knee arthroplasty: a prospective cohort study

ObjectiveTo investigate whether the functional outcomes were affected by the change in posterior tibial slope (PTS) after using a predetermined PTS for primary cruciate-retaining total knee arthroplasty (CR-TKA).MethodsProspective cohort study of 152 patients who underwent primary CR-TKA with a standardized PTS of 5º regardless of the native PTS. Patients were classified postoperatively in two ways. Firstly, according to the PTS change from preoperative to postoperative (increased or decreased PTS group). Secondly, according to the PTS difference between preoperative and postoperative ≤ 4º (group A) and > 4º (group B). The functional outcomes were assessed with the Knee Society Scores (KSS), McMaster Universities Osteoarthritis Index questionnaire (WOMAC), and range of motion (ROM). Preoperative and postoperative PTS were measured on lateral knee radiographs.ResultsThe minimum follow-up was 5 year. There were no significant differences at the final follow-up in functional outcomes between increased (88 patients) and decreased (64 patients) PTS groups. Likewise, there were no significant differences in functional outcomes between group A (79 patients) and group B (73 patients). In multivariate analysis, the PTS change was not significant predictor for improvement in functional outcome (OR 1.08; 95% CI 0.70–1.40; p = 0.061).ConclusionThe PTS change between preoperative and postoperative has no influence on the functional outcomes using a CR-TKA. A standardized PTS regardless of the native is a reliable procedure for primary CR-TKA.

Comparative outcomes of patient-specific instrumentation, the conventional method and navigation assistance in open-wedge high tibial osteotomy: A prospective comparative study with a two-year follow up

BackgroundTo compare and analyze the correction precision, clinical outcomes and complications among the three methods of performing open-wedge high tibial osteotomy (HTO), including patient-specific instrumentation (PSI), conventional method and navigation assistance. MethodsIn this prospective, single-center study, we randomly assigned patients with knee osteoarthritis in a 1:1:1 ratio to undergo Open-wedge high tibial osteotomy (OWHTO) with conventional method, navigation assistance or PSI. The primary outcome was the target/observed hip–knee–ankle (HKA) angle difference at 1 month postoperatively. Secondary outcomes were changes in the postoperative posterior tibial slope (PTS) at 1 month and clinical outcomes including knee pain on a visual analogue scale (ranging from 0 to 100, with higher scores indicating more severe pain), Lysholm and Western Ontario and McMaster Universities Osteoarthritis Index (ranging from 0 to 240) scores at 1 month, 6 months, 12 months, and 24 months. ResultsFrom 2017 through 2019, a total of 608 patients were screened; of those patients, 144 were enrolled, with 48 in each group. The primary outcome of the HKA difference was 2.6 ± 2.0° in the conventional group, 2.3 ± 1.5° in the navigation group and 0.6 ± 1.0° in the PSI group (P < 0.001). Secondary outcomes including changes in the postoperative PTS and clinical outcomes at 1 month, 6 months, and 12 months were in the same direction as the primary outcome. There were no significant differences in the complications among the three groups. ConclusionsIn the present study, none of the three methods showed superiority in objective correction precision and clinical outcomes at 2 years.

Risk Factors Affecting Return to Sports and Patient-Reported Outcomes After Opening-Wedge High Tibial Osteotomy in Active Patients.

Background:Although opening-wedge high tibial osteotomy (OWHTO) is favored for active patients who expect to return to sports, there is still a lack of robust evidence for factors affecting their recovery.Purpose:To identify (1) risk factors leading to a decreased level of return to preoperative sports after OWHTO and (2) patient characteristics and intraoperative factors influencing patient-reported outcomes after return to sports.Study Design:Case-control study; Level of evidence, 3.Methods:Included were 69 patients who underwent OWHTO and who expected to return to their preoperative level of sports, measured as a Tegner activity level ≥2. All included patients had a minimum of 1 year of follow-up data. Logistic regression analyses were performed to assess the effect of independent variables on the level of return to preoperative sports after surgery; the independent variables were age, sex, body mass index, preoperative Tegner score, preoperative Kellgren-Lawrence grade, preoperative percentage of mechanical axis (%MA), opening gap width, concomitant meniscal treatment, postoperative %MA, postoperative medial proximal tibial angle (MPTA), and postoperative posterior tibial slope. Univariate and multiple regression analyses were performed to assess for influencing factors on postoperative International Knee Documentation Committee (IKDC) subjective scores in patients who were able to return to sports.Results:Of the 69 patients, 51 (73.9%) returned to sports after OWHTO. High preoperative Tegner scores were statistically associated with a decrease in return to sports (odds ratio, 1.494; P = .033). Multiple regression analysis (n = 46 patients) identified that a higher postoperative MPTA was associated with a decreased IKDC subjective score after return to sports (r = –0.345; P = .019).Conclusion:Higher postoperative MPTA was associated with the worsening of patient-reported outcomes among those patients who did return to their preoperative sports after OWHTO. Also, participation in high-activity sports was confirmed to be a significant risk factor for a decreased rate of return to preoperative sports. These findings can support preoperative planning and intraoperative decision making, particularly for active patients.

Large Reduction in Postoperative Posterior Tibial Slope Risks Anterior Collapse of the Tibial Component in Fixed-Bearing Unicompartmental Knee Arthroplasty

BackgroundAlthough the posterior tibial slope (PTS) of the tibial component in unicompartmental knee arthroplasty is recommended to be between 3° and 7°, variations in preoperative PTS are wide. The purpose of this study was to evaluate the influence of the changes in preoperative and postoperative PTS on clinical outcomes. MethodsOne-hundred and eighty-two knees that underwent medial fixed-bearing unicompartmental knee arthroplasty were evaluated retrospectively. The mean follow-up period was 36.4 ± 13.2 months (range, 24 to 63 months). Preoperative and postoperative PTS were measured on lateral radiographs. Knees were classified in the large reduction group if the postoperative PTS was reduced by more than 5° compared with the preoperative value and in the small reduction group if not. Knee flexion angle and 2011 Knee Society Knee Scoring System were evaluated at the last follow-up of at least 2 years. ResultsThirty-three knees were classified in the large reduction group, and 149 knees were classified in the small reduction group. The preoperative and postoperative PTS of large and small reduction groups were 10.9 ± 2.2, 3.6 ± 2.4 degrees and 7.7 ± 2.7, 7.1 ± 2.4 degrees, respectively. Flexion angle and 2011 Knee Society Knee Scoring System were not significantly different between the groups. However, the incidence of anterior collapse of the tibial component in the large group was significantly higher than that in the other group (P < .001). ConclusionsLarge reduction in the postoperative PTS may be associated with anterior tibial collapse, and therefore this study shows one potential benefit for matching native slope.

Distal tibial tubercle osteotomy can lessen change in patellar height post medial opening wedge high tibial osteotomy? A systematic review and meta-analysis

ObjectiveMedial opening wedge high tibial osteotomy (MOWHTO) is a mainstream surgical method for treating early medial compartment knee osteoarthritis. Undesirable sequelae such as patella infera may happen following tuberosity osteotomy. We conducted this systematic review and meta-analysis to compare the change in patellar position after proximal tibial tubercle osteotomy (PTO) versus distal tibial tubercle osteotomy (DTO) intervention.MethodsThe 11 studies were acquired from PubMed, Medline, Embase and Cochrane Library. The data were extracted by two of the coauthors independently and were analyzed by RevMan5.3. Mean differences, odds ratios and 95% confidence intervals were calculated. Cochrane Collaboration’s Risk of Bias Tool and Newcastle–Ottawa Scale were used to assess risk of bias.ResultsEleven observational studies were assessed. The methodological quality of the trials ranged from moderate to high. The pooled results of postoperative patellar height (Caton-Deschamps index and Blackburne-Peel index) and postoperative complications showed that the differences were statistically significant between PTO and DTO interventions. Patellar index ratios decreased significantly in the PTO groups, and 12 (9.2%) complications under DTO surgery and 2 (1.6%) complications under PTO surgery were reported. The differences of postoperative posterior tibial slope (angle) was not statistically significant, but postoperative posterior tibial slope of both groups increased. Sensitivity analysis proved the stability of the pooled results and the publication bias was not apparent.ConclusionsDTO in MOWHTO maintained the postoperative patellar height, and clinically, for patients with serious patellofemoral osteoarthritis, DTO can be preferred. Postoperative complications are easily preventable with caution. In view of the heterogeneity and small sample size, whether these conclusions are applicable should be further determined in future studies.

The association of posterior tibial slope changes between joint gap contact force and the range of motion in Oxford mobile bearing unicompartmental knee arthroplasty

Objective: To investigate the correlation between the change of posterior tibial slope (PTS) after unicompartmental knee arthroplasty (UKA) and the contact force at the end stage of knee flexion and extension, as well as the postoperative range of motion. Methods: The data of 38 cases (46 knees) of UKAs undertaken in China-Japan Friendship Hospital from June 2020 to June 2021 were analyzed in this study. A custom-designed force sensor was used to measure gap contact force in the medial gap of UKA. The correlations between each two of the three factors-the change of PTS (∆PTS), the gap contact force of full extension and deep flexion and the range of knee motion were analyzed. Results: Totally of 38 patients (46 knees) were enrolled, including 14 males and 24 females, aged (69.1±7.4) years, with an average follow-up of (11.2±3.7) months. The average gap contact force was (88.3±40.6)N, the adjusted contact force of the full extension gap was 81.7%±33.8%, while that of the deep flexion gap was 55.6%±31.0%. At the last follow-up, the fixed flexion degree[M(Q1, Q3)] was 0°(0°, 3°), which was significantly lower than the preoperative value of 0°(0°, 5°) (P<0.05); the postoperative max flexion degree was 115.9°±16.4°, it was increased when compared with the preoperative value of 112.0°±16.8° (P<0.05); and the postoperative PTS was 8.3°±2.7°, and there was no significant difference with the preoperative value (8.6°±2.1°,P>0.05). There was a positive correlation between ∆PTS and both the contact force of full extension gap and the fixed flexion degree (r=0.334 and 0.317, P<0.05). Besides, there was a negative correlation between ∆PTS and the contact force of the deep flexion gap (r=-0.397, P<0.05). However, the correlations between these two factors and the max flexion degree were not significant (P>0.05). Conclusions: The reduction of PTS in UKA would reduce the contact force of the full extension gap, as well as the postoperative fixed flexion deformity. Besides, it could increase the contact force of the deep flexion gap, but would not influence the max flexion degree of the knee postoperatively.

CHANGES OF TIBIAL SLOPE AFTER CRUCIATE RETAINING–TOTAL KNEE REPLACEMENT AND THEIR FUNCTIONAL EFFECT OUTCOME

Background &#x0D; Total knee arthroplasty has been regarded as the primary surgical procedure for relieving severe pain in the last stage of degenerative arthritis and experiencing better functional outcomes. many previous studies have been described the effect of posterior tibial slope on functional outcome, but many debates exist.&#x0D; Objectives &#x0D; To find changes of posterior tibial slope in total knee arthroplasty.&#x0D; Patients and Methods&#x0D; Our study includes 50 patients (50 knees) who underwent Cruciate Retaining-Total knee Replacement (CR-TKR) from 10 January 2018 to Nov2019. Posterior tibial slope (PTS) was measured on lateral x-ray. According to the oxford knee score, the functional outcome and the posterior tibial slope were measured preoperatively and postoperatively for each patient.&#x0D; Results&#x0D; Fifty patients underwent CR-TKR. Preoperative PTS and oxford knee scores were 11.7 and 11.72, respectively. Postoperative PTS and oxford knee scores were 9.3 and 39.64, respectively. We divided into Group A: PTS up to 9(24 cases) and Group B PTS more than 9 (26). We analyzed the relationship between PTS and functional outcome according to the oxford knee score. &#x0D; Conclusion&#x0D; Clinical improvements were noticed in both patient groups after CR-TKR.