Preoperative Posterior Tibial Slope Research Articles

Paper 01: Clinical Outcomes Following ACL Reconstruction with Slope Reducing High-Tibial Osteotomy: A Matched Case-Control Study

Objectives: Despite recent efforts, the reinjury rate following anterior cruciate ligament (ACL) reconstruction remains high, with documented reports of up to 30%. According to retrospective evidence, high posterior tibial slope (≥12°) has been identified as an anatomic risk factor contributing increased graft reinjury rates. Surgeons are therefore exploring the effectiveness of slope reducing high tibial osteotomy (SRO) as a means of modifying this potential risk factor. While cadaveric models suggest that this surgical procedure decreases the forces across the ACL graft, there are few clinical trials examining its’ safety and clinical effectiveness in patient samples. Therefore, the purpose of this study is to compare functional performance and graft reinjury rates between patients undergoing ACL reconstruction surgery with SRO versus matched controls undergoing isolated ACL reconstruction. We hypothesized that patients undergoing ACL reconstruction with SRO would exhibit similar performance outcomes with a low failure rate when compared to their matched counterparts. Methods: A retrospective matched-case control study was conducted in accordance with the ‘Strengthening the Reporting of Observational Studies in Epidemiology’ guidelines for patients undergoing ACL reconstruction (Figure 1), utilizing a single surgeon database (n=1978). The experimental group (ACL+SRO) consisted of patients ages 18-50 years old that were at least 24-months out of ACL reconstruction with a concomitant SRO. Patients were age, sex, and revision-matched to a cohort of individuals undergoing isolated ACL reconstruction. Exclusion criteria consisted of contralateral knee injury (<24 months prior to surgery), isolated coronal-plane high tibial osteotomy, and multiligamentous knee injury. Patient demographics and surgical data were obtained, including pre/postoperative posterior tibial slope (o) for the ACL+SRO group and presurgery activity levels. Data were gathered at return to sports and included knee range of motion, single-leg balance, single-leg hop testing, and self-reported International Knee Documentation Committee and ACL-Return to Sports After Injury (ACL-RSI) scores. Complications and injury surveillance was conducted throughout the postoperative follow-up period. Primary outcome measures included the Single Assessment Numeric Scale (SANE), and graft failure rates at two-years. Secondary outcomes included return to sport rate and level of participation, and postoperative complications (infection, loss of motion, deep vein thrombosis, etc). Generalized Linear Models and chi-square analyses were conducted using SPSS (IBM, Chicago IL) to compare groups with an a-priori alpha level of .05. Results: Of the 1978 patients in the ACL registry, 48 met the study criteria and were included in the analyses (ACL+SRO group, n=24; Isolated ACL group, n=24). Baseline comparisons revealed that the ACL+SRO group had a higher bodyweight (200.9 ±35.1 vs 179.7 ±33.9, P <.001) and subsequent higher body mass index (29.7 ±4.6 vs 26.7 ±5.0, P = .044), Table 1. Additional baseline differences included ACL graft type, and staged procedures ( P < .05, Table 2). The mean preoperative posterior tibial slope was 17.0° ±2.7° and 7.0° ±2.2° following SRO (mean diff: -10.0°, P <.001). Table 3 depicts the comparisons at return to sport, with the ACL+SRO group demonstrating longer time to return ( P < .001) and lower ACL-RSI scores ( P = .027). At 2 years, there were no statistical differences in SANE score (85.3 ±7.3 vs 88.2 ±9.7, P = .349), graft reinjury rate (0.0% vs 0.0%, P = 1.000), rate of return to sports (85.7% vs 91.7%, P = .844), or level of return to sports between groups with 45.8% (n=11) of the ACL+SRO group returning to a level I or II cutting and pivoting sport versus 54.2% (n=13) in the Isolated ACL group ( P = .656). There were no reported postoperative infections or deep vein thromboses in either group (P > .05). Conclusions: The current study suggests that SRO in the setting of ACL reconstruction for large posterior tibial slope deformities is effective at correcting malalignment, restoring objective and self-reported function, and avoiding graft failure out to 2 years. This procedure also holds promise to allow a majority of patients to return to various levels of sporting activities. To our knowledge, this is the first comparative study examining the return to sports and 2-year outcomes of this population to a matched isolated ACL cohort. While these data do provide evidence for ongoing investigation, we recommend the performance of larger clinical trials to confirm these results. [Figure: see text][Figure: see text][Figure: see text][Figure: see text]

Comparison of Side-to-Side Difference in Posterior Tibial Slope in Knees With Acute Versus Chronic Anterior Cruciate Ligament Deficiency.

The posterior tibial slope (PTS) is an important feature in knee joint biomechanics and indicates anterior-posterior knee stability. Increased PTS is a known risk factor for both primary anterior cruciate ligament (ACL) rupture and postreconstruction rerupture. To investigate the effect of long-term exposure to ACL deficiency on the PTS and the sagittal anatomy of the proximal tibia. Cross-sectional study; Level of evidence, 3. A total of 44 patients (38 men, 6 women) with a history of knee injury and ACL rupture confirmed by magnetic resonance imaging and physical examination were included in this study. Patients were divided into those with chronic ACL deficiency (group 1: injured ≥5 years prior; n = 22) and acute ACL deficiency (group 2: injured <1 year prior; n = 22). The medial and lateral tibial plateau PTS and anterior tibial translation were measured on monopodal weightbearing knee radiographs at 20° of flexion. The mechanical tibiofemoral angle (MTFA) and the medial proximal tibial angle (MPTA) were measured using an orthoroentgenogram. The side-to-side difference between the affected and unaffected knees was also calculated for all measurements. The mean duration of exposure to ACL deficiency was 7.6 years (range, 5-15 years) in group 1 and 4.4 months (range, 1-11 months) in group 2. Regarding the side-to-side differences in angular measurements, a higher medial PTS (affected vs unaffected: 12.4° vs 10.1°; P = .007), higher lateral PTS (11° vs 8.9°; P = .011), and increased varus alignment on both the MTFA (4.3° vs 2.4°; P = .036) and the MPTA (84.9° vs 86.3°; P = .033) were found in group 1, while no significant differences in angular measurements were found in group 2. Compared with group 2, patients in group 1 had a significantly higher side-to-side difference in the medial PTS (2.3° vs 0.1°; P = .0001), lateral PTS (2.1° vs 0.4°; P = .0001), and MPTA (1.4° vs 0.1°; P = .002). This study showed that the affected knees of patients with chronic ACL deficiency (≥5 years) had higher medial and lateral PTS compared with the unaffected contralateral knees. Therefore, when planning ACL reconstruction for patients with a history of long-term ACL deficiency, it is crucial to measure the preoperative PTS accurately.

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.

Outcomes of Slope-Reducing Proximal Tibial Osteotomy Combined With a Third Anterior Cruciate Ligament Reconstruction Procedure With a Focus on Return to Impact Sports

Background: An increased posterior tibial slope (PTS) is a proven risk factor for both native anterior cruciate ligament (ACL) and ACL graft insufficiency. Anterior closing wedge high tibial osteotomy (ACW-HTO) for PTS correction is a validated procedure in revision ACL reconstruction (ACLR). Purpose/Hypothesis: The aim of this study was to evaluate the effect of combined ACW-HTO and at least a second revision ACLR procedure on knee stability, function, and sports performance in a large series of patients. The hypothesis was that patients would return to impact sports after ACW-HTO combined with a second or third revision ACLR procedure. Study Design: Case series; Level of evidence, 4. Methods: A total of 64 patients who underwent a second (or more) revision ACLR procedure and ACW-HTO between June 1, 2015, and June 1, 2019, and had a PTS >12° were included. The mean age was 29.60 ± 6.31 years, and the mean preoperative PTS was 13.79°± 1.50°. The cases were analyzed at a mean follow-up of 2.96 ± 0.83 years (range, 2-5 years). At the last follow-up, the rate of patients returning to impact sports (based on the University of California, Los Angeles [UCLA], activity scale), ACL graft status (per magnetic resonance imaging), International Knee Documentation Committee (IKDC) scores, Lysholm scores, and laxity measurements using a knee arthrometer were recorded. Results: The total number of patients participating in impact sports and high-impact sports was as follows: 43 and 30, respectively, before the injury; 0 and 0, respectively, preoperatively; and 31 and 12, respectively, postoperatively. At the last follow-up, the UCLA score was ≥8 in 48.44% of the patients, and only 16 patients returned to their preinjury level of activity. At a minimum of 2 years of follow-up, there was clinical improvement in the IKDC score from 37.98 ± 12.48 preoperatively to 69.06 ± 12.30 postoperatively (P < .0001), in the Lysholm score from 51.94 ± 14.03 preoperatively to 74.45 ± 11.44 postoperatively (P < .001), and in the UCLA score. However, this clinical improvement did not equate to preinjury values for all outcome scores (P < .001). The preinjury IKDC and Lysholm scores were 76.98 ± 11.71 and 89.26 ± 8.91, respectively. The mean change in anterior knee laxity using a knee arthrometer at 134 and 250 N was −4.03 ± 0.18 mm and −3.63 ± 0.16, respectively. There were 3 cases of a rerupture with a severe pivot shift on the clinical examination. None of these patients underwent revision per the patient's preference. Increased knee recurvatum was observed in one-third of the patients, but all were asymptomatic. Conclusion: In the setting of chronic ACL-deficient knees, PTS reduction (ACW-HTO) with revision ACLR restored knee stability and improved function with an acceptable rate of specific complications. Increased knee recurvatum was observed in one-third of the patients, but all were asymptomatic. Also, approximately half of the patients were able to return to impact sports.

Poster 350: Outcomes of Anterior Closing Wedge High Tibial Osteotomy in Patients Undergoing Revision ACL Reconstruction

Objectives: Graft failure rates following anterior cruciate ligament (ACL) reconstruction have been reported up to 30%. According to the literature, one anatomic variant linked to graft reinjury is a high posterior tibial slope. As a result, surgeons are exploring the effectiveness of slope reducing high tibial osteotomy (HTO) to reduce the subsequent reinjury risk. While cadaveric models indicate that this procedure decreases the forces across the ACL graft, there is limited evidence demonstrating its efficacy in clinical trials. Therefore, the purpose of this study was to compare self-reported patient outcomes between patients undergoing ACL revision surgery with a slope reducing high tibial osteotomy and matched controls undergoing revision ACL reconstruction without slope reducing HTO. We hypothesized that patients undergoing ACL+HTO would exhibit similar outcomes with a low failure rate when compared to their matched counterparts. Methods: A retrospective matched-case control study was conducted for patients undergoing ACL revision reconstruction from 2018 to 2021, utilizing a single surgeon database (n = 1,781). Patients in the HTO group were included if they were at least one year out from surgical ACL reconstruction and slope reducing osteotomy. Patients were excluded if they were undergoing primary ACL reconstruction or no concomitant ACL reconstruction. Patients in the ACL+HTO group were age, gender, and setting-matched to a control group of patients undergoing revision ACL reconstruction. Descriptive patient demographic and surgical data were obtained, including pre/postoperative posterior tibial slope(o) for the HTO group. Complications and injury surveillance was conducted throughout the postoperative follow-up period. Primary outcome measures included the Single Assessment Numeric Scale (SANE), and graft failure rates at 24 months. Secondary outcomes included return to sport rate/level and postoperative complications (infection, loss of motion, deep vein thrombosis, etc). Generalized linear models were conducted using parametric and nonparametric equivalents to compare baseline and outcome measures between groups with an a-priori alpha level of .05. Results: From a group of 364 revision ACL reconstructions, 9 patients met the inclusion criteria for the ACL+HTO group (Table 1). This group was age, gender and revision matched to 30 patients in the control group. Baseline comparisons revealed that the ACL control group weighed more than the experimental group (198.2 ±26.4 vs 183.7 ±21.7, P &lt;.001), however all other comparisons were not statistically different. The mean pre operative posterior tibial slope was 19.2o ±4.1o and 7.7o ±2.3o following HTO (mean diff: -11.5o, P &lt;.001). Mean time to follow-up was 1.82 ±0.3 years. At follow-up, there were no statistical differences in self-reported knee function (SANE score), graft reinjury rate, rate of return-to- sport, or level of return to sport between groups (Table 3). There were no graft reinjuries reported in the ACL+HTO group and approximately 85.8% returned to some level of sporting activity with 42% returning to a level I or II cutting and pivoting sport. Conclusions: Preliminary evidence provided in the current study suggests that slope reducing HTO in the setting of revision ACL reconstruction for large posterior tibial slope deformities is effective at correcting malalignment and avoiding graft failure out to 2 years. This procedure also holds promise to allow a majority of patients to return to various levels of sporting activities. To our knowledge, this is the first comparative study comparing the intermediate outcomes of this subpopulation to a matched revision ACL cohort. While these data do provide evidence for ongoing investigation, it is important to note that this pilot study is underpowered and we strongly recommend the performance of larger clinical trials to confirm these results. [Table: see text][Table: see text]

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.

Risk factors for contralateral anterior cruciate ligament injury after primary anterior cruciate ligament reconstruction

To investigate the risk factors of contralateral anterior cruciate ligament (ACL) injury after primary ACL reconstruction. A retrospective review was conducted on the 716 patients with ACL injury who received primary ACL reconstruction surgery and met the selection criteria between January 2012 and September 2018. After a mean follow-up period of 7.6 years (range, 4-10 years), 65 patients (9.1%) experienced contralateral ACL injury (injured group) and 651 patients (90.9%) did not (uninjured group). There was no significant difference in age, body mass index, and preoperative Lachman test degree between groups ( P>0.05). However, the proportion of female in the injured group was significantly higher than that of male ( P<0.05), and the preoperative posterior tibial slope (PTS) was significantly higher than that of the uninjured group ( P<0.05). Using the outcome of contralateral ACL injury as the dependent variable, the clinical data of the patient was first used as the independent variable, and univariate COX regression was used to analyze the prognostic influencing factors. Then, the indicators with differences in univariate COX regression were used as the independent variable, and multivariate COX regression was used to analyze the independent risk factors affecting prognosis. Log-Rank (Mantel-Cox) test was used to test and analyze the occurrence time of contralateral ACL injury in patients of different genders; X-tile software was used to analyze the occurrence time of contralateral ACL injury in patients with different PTS using Log-Rank (Mantel-Cox) test and PTS cut-off values. Univariate COX regression analysis showed that gender and PTS were influence factors for contralateral ACL injury ( P<0.05); further multivariate COX regression analysis showed that female and increased PTS were independent risk factors for contralateral ACL injury ( P<0.05). The Log-Rank (Mantel-Cox) test results showed that the contralateral ACL injury occurred in female at 8.853 (8.600, 9.106) years, which was significantly shorter than that in male [9.661 (9.503, 9.819) years] ( χ 2=20.323, P<0.001). Using X-tile software to analyze the cut-off value of PTS, it was found that the cut-off value of PTS for contralateral ACL injury was 10.92°. According to the Log-Rank (Mantel-Cox) test, it was found that the contralateral ACL injury occurred in 5.762 (4.981, 6.543) years in patients with PTS≥10.92°, which was significantly shorter than patients with PTS<10.92° [9.751 (9.650, 9.853) years]( χ 2 =302.479, P<0.001). Female and PTS≥10.92° after primary ACL reconstruction are independent risk factors for contralateral ACL injury.

Closing-Wedge Posterior Tibial Slope-Reducing Osteotomy in Complex Revision ACL Reconstruction.

A posterior tibial slope (PTS) >12° has been shown to correlate with failure of anterior cruciate ligament (ACL) reconstruction (ACLR). PTS-reducing osteotomy has been described to correct the PTS in patients with a deficient ACL, mostly after failure of primary ACLR. To report radiologic indices, clinical outcomes, and postoperative complications after PTS-reducing osteotomy performed concurrently with revision ACLR (R-ACLR). Case series; Level of evidence, 4. A review of medical records at 3 institutions was performed of patients who had undergone PTS-reducing osteotomy concurrently with R-ACLR between August 2010 and October 2020. Radiologic parameters recorded included the PTS, patellar height according to the Caton-Deschamps Index (CDI), and anterior tibial translation (ATT). Patient-reported outcomes (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]), reoperations, and complications were evaluated. Included were 23 patients with a mean follow-up of 26.7 months (range, 6-84 months; median, 22.5 months). Statistically significant differences from preoperative to postoperative values were found in PTS (median [range], 14.0° [12°-18°] vs 4.0° [0°-15°], respectively; P < .001), CDI (median, 1.00 vs 1.10, respectively; P = .04) and ATT (median, 8.5 vs 3.6 mm, respectively; P = .001). At the final follow-up, the IKDC score was 52.4 ± 19.2 and the KOOS subscale scores were 81.5 ± 9.5 (Pain), 74 ± 21.6 (Symptoms), 88.5 ± 8 (Activities of Daily Living); 52.5 ± 21.6 (Sport and Recreation), and 48.8 ± 15.8 (Quality of Life). A traumatic ACL graft failure occurred in 2 patients (8.7%). Reoperations were necessary for 6 patients (26.1%) because of symptomatic hardware, and atraumatic recurrent knee instability was diagnosed in 1 patient (4.3%). Tibial slope-reducing osteotomy resulted in a significant decrease of ATT and can be considered in patients with a preoperative PTS ≥12° and ≥1 ACLR failure. In highly complex patients with multiple prior surgeries, the authors found a reasonably low graft failure rate (8.7%) when utilizing PTS-reducing osteotomy. Surgeons must be aware of potential complications in patients with multiple previous failed ACLRs.

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.

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.

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.

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.

Analysis of the influence of tibial component posterior slope angle on short- and mid-term effectiveness of unicompartmental knee arthroplasty

To investigate the influence of tibial component posterior slope angle (TCPSA) on the short- and mid-term effectiveness of unicompartmental knee arthroplasty (UKA). The clinical data of the patients with anterior medial knee osteoarthritis (KOA) treated by UKA between May 2014 and May 2019 were retrospectively analysed. There were 10 males and 45 females with a median age of 68 years (range, 49-83 years). The body mass index (BMI) was 27.63-52.26 kg/m 2, with an average of 40.04 kg/m 2. There were 28 cases of left knee, 21 cases of right knee, and 6 cases of double knees. The disease duration was from 7 months to 12 years, with an average of 4.33 years. Measurements of posterior tibial slope (PTS) and TCPSA were performed on the knee joint X-ray films of patients before operation and at last follow-up, respectively. According to the postoperative TCPSA, patients were divided into TCPSA<4° group (group A), 4°≤TCPSA<9° group (group B), and TCPSA>9° group (group C) with the quartile method. Baseline data such as age, gender, BMI, and affected side were compared among the 3 groups, as well as the Hospital for Special Surgery (HSS) score, visual analogue scale (VAS) score, and range of motion (ROM) before and after operation. All 55 patients were followed up 17-72 months, with an average of 36 months. No complication such as prosthesis loosening, infection, tibial plateau collapse, and dislocation of the meniscus pad occurred. The preoperative PTS was (7.38±3.37)°, and the postoperative TCPSA was (6.25±3.22)°, showing no significant difference ( t=1.815, P=0.074). According to postoperative TCPSA, there were 12 knees in group A, 32 in group B, and 17 in group C. There was no significant difference in age, gender, BMI, affected side, and preoperative HSS scores, ROM, and VAS scores among the 3 groups ( P>0.05). At last follow-up, the HSS scores, ROM, and VAS scores of the 3 groups significantly improved when compared with preoperative ones ( P<0.05). There was no significant difference in the difference of the above indicators before and after operation among 3 groups ( P>0.05). The patients with anterior medial KOA may have good short- and mid-term effectiveness after UKA. Among the recommended range of TCPSA, there is no significant influence on the postoperative short- and mid-term effectiveness. Long-term effectiveness need to extend the follow-up time and expand the sample size for research verification.

Relevance of the Tibial Slope on Functional Outcomes in ACL-Deficient and ACL Intact Fixed-Bearing Medial Unicompartmental Knee Arthroplasty

BackgroundExcessive posterior tibial slope in medial unicompartmental knee arthroplasty (UKA) has been implicated in early failure. The purpose of this study was to evaluate the relationship between preoperative posterior tibial slope and postoperative slope of the implant (PSI) on outcomes in patients with anterior cruciate ligament (ACL) intact and ACL-deficient knees after fixed-bearing medial UKA. MethodsPatients who underwent a medial UKA between 2002 and 2017 with a minimum 3-year follow-up were included. Preoperative posterior tibial slope and postoperative PSI were measured. Outcomes measures included Knee Injury and Osteoarthritis Outcomes Score (KOOS) subscales, Lysholm, and VR-12. Failure was defined as conversion to total knee arthroplasty. ResultsOf 241 knees undergoing UKA, 131 patients (70 women, 61 men; average age of 65 ± 10 years (average BMI of 27.9 ± 4) were included. For all patients, survivorship was 98% at 5 years and 96% at 10 years with a mean survival time for UKA was 15.2 years [95% CI: 14.6-15.7]. No failure had a PSI >7°. There were no superficial or deep infections. There were no significant differences in outcome scores between the ACL intact and the ACL-deficient group; therefore, the data were combined for analysis. At mean 8-year follow-up, KOOS pain scores were better in patients with PSI ≤7° (87 ± 16) than those with PSI >7° (81 ± 15). 76% of patients with PSI ≤7° reached the Patient Acceptable Symptom State for KOOS pain; whereas, 59% of patients with PSI >7° reached PASS for KOOS pain (P = .015). ConclusionPatients with postoperative posterior slope of the tibial implant >7° had significantly worse postoperative pain, without conversion to TKA, and with maintenance of high function. In ACL deficient and intact knees, nonrobotically-assisted, fixed-bearing medial UKA had a 96% survivorship at 10 years.

Effects of different prosthetic instrumentations on tibial bone resection in total knee arthroplasty

Our aim was to assess the accuracy of the obtained posterior tibial slope (PTS) with a fixed angle cutting block. 247 TKAs in 213 patients were reviewed. We included 104 Legion Prosthesis, 76 U2 Knee Prosthesis, 46 NexGen LPS-Flex Prosthesis, and 21 Vanguard Knee System products. Preoperative and postoperative PTS were measured via expanded lateral tibia radiographs. For postoperative PTS, the Legion group had significantly smaller slopes than the U2 Knee group and Vanguard group. However, there was no significant difference between the Legion and NexGen groups, and no significant difference among the NexGen, U2 Knee, and Vanguard groups. Multiple linear regression showed that the different tibial lengths and preoperative PTS had statistically significant effects on postoperative PTS. However, there were weak correlations between the tibial length and PTS, and between preoperative and postoperative PTS. For TKA, although the PTS is not completely consistent with the angle of the cutting block, using conventional tibial bone resection technology with different tibial cutting instrumentations provided by various manufacturers in TKA can obtain safe PTS.

The Ideal Hinge Axis Position to Reduce Tibial Slope in Opening-Wedge High Tibial Osteotomy Includes Proximalization-Extension and Internal Rotation

To evaluate the effect of the hinge axis position on the posterior tibial slope (PTS) in medial opening-wedge high tibial osteotomy. This study included adults with medial-compartment osteoarthritis who had computed tomography (CT) scans available that were amenable to Bodycad Osteotomy software analysis. Virtual osteotomies modeling a 10-mm medial opening-wedge gap were performed. The hinge axis was rotated internally and externally and was proximalized-extended and distalized-flexed with respect to the anterior tibial cortex for 5°, 10°, 15°, and 20°. Each resultant PTS was recorded and compared with the results obtained from the true lateral hinge position and with the preoperative PTS. Computed tomography scans from 10 patients were used. Strong linear correlations were found with each hinge axis position change and the resultant PTS. The trend-line differences were statistically significant by single-factor analysis of variance (P < .001). The PTS decreased for an anterolateral hinge, whereas it increased for a posterolateral hinge. Linear regression analysis showed that rotating the hinge axis by 9.0° externally or angulating the hinge axis by 21.8° of distalization-flexion would result in increasing the tibial slope by 1° whereas rotating the hinge axis by 8.7° internally or angulating the hinge axis by 21.6° of proximalization-extension would decrease the tibial slope by 1°. Distalization-flexion and external rotation of the hinge axis position led to stepwise increases in the PTS, whereas proximalization-extension and internal rotation led to decreases in the PTS. Our findings suggest that when performing medial opening-wedge high tibial osteotomy and aiming to decrease the PTS, the surgeon should aim to achieve maximal internal rotation (producing an anterolateral hinge), as well as proximalization-extension, of the hinge axis. This study quantifies and provides a model for the effect of the hinge axis position for a predetermined angular correction on the PTS.

A Current Prosthesis With a 1-mm Thickness Increment for Polyethylene Insert Could Result in Fewer Adjustments of Posterior Tibial Slope in Cruciate-Retaining Total Knee Arthroplasty

BackgroundTo compare posterior tibial slope (PTS) and incidence of excessive PTS between cruciate-retaining (CR) total knee arthroplasties (TKAs) with the current prosthesis, providing a 1-mm increment of polyethylene insert thickness, and its predecessor, providing a 2-mm increment. MethodsEach of 154 CR TKAs with Persona (current group) and NexGen (predecessor group) prostheses with a minimum follow-up period of 2 years were retrospectively reviewed. Preoperative demographics, including age, sex, and body mass index, were similar. Factors affecting the flexion gap were matched in terms of preoperative range of motion, mechanical axis, PTS, preoperative and postoperative posterior femoral offset (PFO), and PFO ratio. The PTS was evaluated radiographically. The incidence of excessive PTS (PTS > 10°) and the frequency of intraoperative PTS-increasing procedures were investigated. ResultsThere were no significant differences in preoperative and postoperative range of motion, mechanical axis, PFO, and PFO ratios between the 2 groups. The preoperative PTS was not significantly different, but the postoperative PTS was significantly lower in the current group (4.6° vs 6.2°, P < .001). There was no case of excessive PTS in the current group, but there were 9 cases (5.8%) in the predecessor group (P = .030). The intraoperative PTS-increasing procedure was performed more frequently in the predecessor group (12.3% vs 21.4%, P = .047). ConclusionThe current prosthesis providing a 1-mm increment of polyethylene insert thickness could decrease the PTS and the occurrence of excessive PTS in CR TKA. The target angle for PTS can be decreased in TKA using the current prosthesis in comparison with its predecessor. Level of EvidenceIII.

Reproducing the Native Posterior Tibial Slope in Cruciate-Retaining Total Knee Arthroplasty: Technique and Clinical Implications.

Total knee arthroplasty (TKA) profoundly influences knee biomechanics. Using an arbitrary (often 3° to 5°) posterior tibial slope (PTS) in all cases seldom will restore native slope. This study examined whether the native PTS could be reproduced in cruciate-retaining TKA and how this would influence clinical outcome. Radiographic and clinical outcomes of 215 consecutive TKAs using the PFC sigma cruciate-retaining implant were evaluated. The tibial bone cut was planned to be made parallel to the native anatomical slope in the sagittal plane. The PTS was measured with reference to the proximal tibial medullary canal (PTS-M) and the proximal tibial anterior cortex (PTS-C) on true lateral radiographs using a picture achieving and communication system. Knee range of motion (ROM), Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Short Form Health Survey (SF-12) were evaluated. Mean preoperative PTS-M was 6.9°±3.3°, and mean postoperative PTS-M was 7.0°±2.4°. Mean preoperative PTS-C was 12.2°±4.2°, and mean postoperative PTS-C was 12.6°±3.4°. Preoperative and postoperative PTS were not significantly different for both techniques (P>.05). An arbitrary 3° as an acceptable range for PTS-M was achieved in 144 knees (67%) (group 1), and 71 knees (33%) had a difference of more than 3° (group 2). Group 1 had a significantly larger gain in ROM (P=.04) as well as improved Knee Society, WOMAC, and SF-12 physical scores compared with group 2 (P<.01). The modified surgical technique reproduced the native tibial slope in cruciate-retaining TKA. Reproduction of the native PTS within 3° resulted in better clinical outcomes manifested by gain in ROM and knee functional outcome scores. [Orthopedics. 2020; 43(1):e21-e26.].

Decreased Posterior Tibial Slope Does Not Impact Postoperative Posterior Knee Laxity after Double-Bundle Posterior Cruciate Ligament Reconstruction

Objectives: Recent clinical studies have identified sagittal plane posterior tibial slope as a risk factor for increased postoperative laxity after single-bundle (SB) posterior cruciate ligament reconstruction (PCLR). However, the effect of tibial slope and its role in graft laxity following double-bundle (DB) PCLR has not been investigated clinically. Therefore, the purpose of this study was to retrospectively compare the degree of posterior tibial slope and its impact on posterior tibial translation (PTT) after DB PCLR. It was hypothesized that preoperative tibial slope would not be associated with graft laxity following DB PCLR. Methods: Patients who underwent primary DB PCLR without ACL injury between 2010 and 2017 by a single surgeon were retrospectively analyzed. Measurements of posterior tibial slope were performed using the lateral radiograph and PTT was measured using kneeling PCL stress radiographs, preoperatively and at a minimum of 1-year postoperatively. Linear regression was used to assess the relationship between native posterior tibial slope and postoperative graft laxity, determined by PCL stress radiographs. Results: One hundred three patients with PCL tears and subsequent DB PCL reconstructions were included. Ninety (87.4%) patients reported a contact mechanism at time of injury, while 13 (12.6%) patients reported a noncontact injury mechanism. Sixty-four (62.1%) patients had combined extra-articular ligament injuries that were concurrently reconstructed with the PCL tear, while isolated PCL tears were identified in 39 (37.9%) patients. Forty-nine (47.6%) patients had an acute (less than 6 weeks) injury, 54 (52.4%) patients had a chronic (greater than 6 weeks) injury at time of imaging and evaluation. Four (4%) patients demonstrated failed PCLRs, as defined by SSD in PTT greater than 8 mm on PCL stress radiographs. The mean posterior tibial slope for all PCL injured patients was 5.9 degrees &amp;#177; 2.2 degrees. There was a significant reduction in the amount of mean SSD in PTT between preoperative (10.6 &amp;#177; .7 mm) and postoperative (1.5 &amp;#177; 2.6 mm) PCL stress radiographs following DB PCLR (95% CI [8.4, 9.8], p &lt; 0.001). Linear regression analysis revealed no significant correlation between preoperative posterior tibial slope and the amount of SSD in PTT on postoperative stress radiographs obtained at a mean 18.5 months postoperatively (R = -0.115, p = 0.249). Similarly, when adjusting for combined ligamentous injury, injury chronicity, mechanism of injury, BMI, and age at surgery via multiple linear regression, preoperative tibial slope was not a significant independent predictor of postoperative SSD in PTT (beta = -0.079, 95% CI [-0.308, 0.150], p = 0.496). Combined injury (beta = -1.01, 95% CI [-2.00, -0.01], p = 0.047) was a significant independent predictor of decreased postoperative SSD in PTT on posterior stress radiographs. Conclusion: Graft laxity, determined by PTT in posterior kneeling stress radiographs, was not influenced by decreased posterior tibial slope in patients following DB PCLRs. Combined PCL injury was a significant independent predictor of decreased postoperative SSD in PTT on posterior stress radiographs. Additionally, the majority of patients (96%) demonstrated improved objective posterior knee stability following DB PCLR. Thus, DB PCLR can be recommended as a surgical treatment option for patients with grade III isolated and combined PCL injuries, irrespective of native posterior tibial slope. [Table: see text]