Femorotibial Angle Research Articles

Anterior Cruciate Ligament Allograft Reconstruction in Females Can Produce Outcomes Comparable to Those of Autografts in Male Counterparts.

There are unique anatomic and geometric risk factors that contribute to higher injury rates of the anterior cruciate ligament (ACL) in women. Allografts are an important alternative option for female patients. Patients who underwent primary ACL reconstruction were retrospectively evaluated. The case group comprised female patients with ACL allograft reconstruction, and the control group comprised male patients with ACL reconstruction. Functional and clinical evaluations were based on the pre- and postoperative Cybex test, Lysholm score, International Knee Documentation Committee subjective and objective measurement criteria, and Tegner Activity Scale questionnaires. Radiological comparisons were performed using the femorotibial angle (FTA), posterior tibial slope (PTS), and intercondylar notch width (INW). The roof inclination angle (RIA) was assessed using magnetic resonance imaging. The two groups [female (44) and male (88)] had an average follow-up period of 57.9±19.3 months and average ages of 36.5±10.9 and 35.2±11.7 years, respectively. Functional and clinical outcomes showed no differences between the groups, except that the return to the pre-injury activity level was higher in the female group (95% vs. 77%, P<0.001). The female group showed larger FTA and PTS and smaller INW and RIA than those of the male group (P<0.001, 0.008, <0.001 and 0.035, respectively). Female ACL allograft reconstruction showed comparable outcomes to those of their male counterparts, and the return to pre-injury activity levels was significantly higher in women. However, women showed lower activity levels and were more vulnerable to geometric risk factors than their male counterparts.

Preservation of the MMPH and Status of the Notch Configurations Are Important Factors for Successful Revision ACL Reconstruction.

The aim of this study was to identify the differences in anatomical factors between the patients who underwent revision and primary anterior cruciate ligament reconstructions (ACLR) and compare the outcomes between the 2 surgeries. Retrospective cohort study. Single institution tertiary academic center between 2014 and 2020. A total of 84 matched patients who underwent revision (group I) or primary ACLR (group II). Radiological evaluations were performed using side-to-side differences (SS-D), femorotibial angle, and posterior tibial slope. The medial meniscus posterior horn status as width (MMPHW), medial tibial plateau width (MTPW), notch configurations, tunnel positions, and sagittal graft angle were measured using 3D-CT and magnetic resonance imaging (MRI). Graft signals were assessed using MRI. The clinical outcomes were assessed. Group I showed larger SS-D and higher mean Howell grade of anterior cruciate ligament (ACL) graft than group II (P = 0.002 and P = 0.004, respectively). Multivariate regression analyses showed that the decreased MMPHW/MTPW ratio (P = 0.010) and notch width index (P < 0.007) were significantly independent factors associated with the higher Howell grade of ACL grafts. The decreased MMPHW/MTPW ratio (P < 0.001) was a significantly independent factor associated with larger SS-D. In the subgroup analysis, all patients in the notchplasty group showed wider notches postoperatively (P < 0.001). Revision ACLRs resulted in worse ACL signal intensity and stability outcome. The results of this study suggest that it may be important to preserve the MMPHW as much as possible and check notch configurations, especially during a revision ACLR.

Primary Total Knee Arthroplasty for Treating Osteoarthritic Knees with Neglected Patellar Dislocation.

Background and Objectives: Neglected patellar dislocation in the presence of end-stage osteoarthritis (OA) is a rare condition characterized by the patella remaining laterally dislocated without reduction. Due to the scarcity of reported cases, the optimal management approach is still uncertain. However, primary total knee arthroplasty (TKA) can serve as an effective treatment option. This study aimed to present the clinical and radiological outcomes achieved using our surgical technique. Materials and Methods: A retrospective review of 12 knees in 8 patients with neglected patellar dislocation and end-stage OA who underwent primary TKA was conducted. The surgical procedure involved conventional TKA techniques (e.g., medial parapatellar arthrotomy) and additional procedures specific to the individual pathologies of neglected patellar dislocation (e.g., lateral release, medial plication, and quadriceps lengthening). Clinical outcomes, including patient-reported outcome measures (PROMs) (Knee Society Scores and the Western Ontario and McMaster Universities Osteoarthritis Index) and knee range of motion (ROM), were assessed preoperatively and two years postoperatively. Radiological measures including mechanical femorotibial angle and patellar tilt angle were assessed preoperatively and until the last follow-up examinations. Any complications were also reviewed. Results: There were significant improvements in all PROMs, knee ROM, and radiological outcomes, including mechanical femorotibial angle and patellar tilt angle (all p < 0.05). At a mean follow-up of 68 months, no major complications requiring revision surgery, including patellar dislocation, were reported. Conclusions: Primary TKA is an effective procedure for correcting various pathologies associated with neglected patellar dislocation in end-stage OA without necessitating additional bony procedures. Satisfactory clinical and radiological outcomes can be expected using pathology-specific procedures.

Occurrence of Patellofemoral Joint Osteoarthritis in Long-Term Postoperative Cases of Open-Wedge High Tibial Osteotomy: Differences in Symptoms Based on Patient-Standing Type Evaluation with and Without Patellofemoral Joint Osteoarthritis

PurposeTo examine the frequency of patellofemoral joint (PFJ) osteoarthritis (OA) and its symptoms in the long-term course of open-wedge high tibial osteotomy (OWHTO).MethodsWe analyzed 113 joints of 91 patients. OA and osteonecrosis (ON) developed in 91 and 22 joints, after an average postoperative period of 127.5 ± 19.5 months. For X-ray evaluation, the standing femorotibial angle (FTA), % mechanical axis (%MA), Caton–Deschamps index (CDI), patellar tilt angle (TA), lateral patellar shift (LPS), and PFJ space width (medial [MJS] and lateral [LJS]) were analyzed. PFJ-associated symptoms were evaluated using the hospital for special surgery patellar score (HSS-PS) and knee injury and osteoarthritis outcome score patellofemoral subscale (KOOS-PF). Statistical analysis was performed with paired and unpaired t tests, and a risk rate of less than 1% was significantly judged.ResultsPreoperative FTA and CDI decreased from 180.8° to 170.0° and 0.88 to 0.70 at the final follow-up. Preoperative %MA lateralized from 20.8 to 66.0 at the final follow-up. TA and LPS values decreased significantly compared with before surgery until plate removal. The MJS and LJS significantly decreased, and OA with a joint space < 3 mm occurred in 14 cases. However, HSS-PS and KOOS-PF scores were not significantly different between the groups with and without OA.ConclusionPFJ OA occurred in 12.4% cases in the long-term postoperative course of OWHTO; however, no symptomatic difference was found in the group with or without OA.

Preoperative Abnormal Posture Improves After Total Knee Arthroplasty: Knee–Hip–Spine Syndrome

BackgroundSpinal, pelvic, and lower extremity alignment is crucial for maintaining a healthy body posture. However, with aging, this posture becomes challenging to maintain due to muscle weakness and skeletal degeneration. Osteoarthritis (OA) of the hip and knee can also lead to abnormal posture, known as hip–spine and knee–spine syndrome. Total knee arthroplasty (TKA) can help relieve pain and improve lower extremity alignment. This may also improve abnormal posture, such as in knee–hip–spine syndrome. However, the condition of the contralateral knee may affect this improvement. This study evaluated the effects of TKA on clinical outcomes and radiographic body posture. MethodsPatients scheduled for primary one-sided TKA were divided into two groups: the unilateral group comprised patients who had contralateral knee OA conditions. The bilateral group included patients who had prior contralateral TKA. Knee range of motion (ROM), the Knee Injury and Osteoarthritis Outcome Score (KOOS), radiographic lateral femorotibial angle (FTA), hip and knee flexion angles, and sagittal vertical axis (SVA) while standing were measured 24 months after TKA. ResultsBoth groups showed improved knee extension, KOOS, and radiographical FTA and hip and knee flexion angles 24 months after TKA. The SVA also improved 6 months after TKA in both groups and was maintained in the bilateral group, while it deteriorated again in the unilateral group 24 months after TKA. ConclusionA TKA can improve abnormal body posture due to knee OA as in knee–hip–spine syndrome. However, the condition of a contralateral knee can affect TKA outcomes.

Evaluation of the usefulness of non-weight-bearing tunnel view using X-ray in the short term after medial meniscus posterior root tear onset: a retrospective study

BackgroundThis study aimed to examine whether the non-weight-bearing tunnel view X-ray is effective for short-term evaluation of medial meniscus posterior root tear (MMPRT) by assessing the X-ray characteristics at the initial and follow-up visits.MethodsThis was a retrospective longitudinal study of 26 enrolled knees diagnosed with MMPRT on magnetic resonance imaging. The distance between the medial tibial eminence and medial femoral condyle (MTE–MFC distance) and medial tibiofemoral joint (MTFJ) width were measured by obtaining non-weight-bearing tunnel view and frontal view X-ray radiographs. The initial and follow-up values at a median interval of 17 days were compared. Additionally, the correlations between the MTE–MFC distance increase rate and body mass index (BMI), age, femorotibial angle (FTA), and posterior tibial slope (PTS) were evaluated using linear regression analysis.ResultsThe tunnel view images of the initial and follow-up X-rays showed a significant increase in the MTE–MFC distance and a significant decrease in the MTFJ width. Furthermore, a moderate correlation was observed between the change in the MTE–MFC distance and the time interval between X-rays. However, no substantial correlation was observed for the change in the MTFJ width over time. Moreover, no significant correlation was observed between the change in the MTE–MFC distance in the non-weight-bearing tunnel view and BMI, age, FTA, and PTS.ConclusionsThe non-weight-bearing tunnel view is highly beneficial for evaluating MMPRT progression in the short term.

Factors Influencing the Postoperative Flexion Angle in Cruciate-Sacrificing Rotating Platform of Total Knee Arthroplasty.

Various factors affect the improvement of range of motion (ROM) after total knee arthroplasty (TKA). However, there are few reports specific to cruciate-sacrificing rotating platform (CSRP) TKA. In this study, factors affecting postoperative ROM improvement of CSRP TKA were investigated. The study included 79 patients with knee osteoarthritis who underwent unilateral CSRP TKA at our institution. The group with an improvement of 5° or more (Δflexion angle) than the preoperative was defined as the good Δflexion group (38 knees), and that with less than 5° was defined as the poor Δflexion group (41 knees). The assessments were performed one day before and one year after surgery. Factors including rest and walking pain, knee flexion and extension angle, isometric knee extension strength, the five subscales of Knee injury and Osteoarthritis Outcome Score (KOOS), α, β, γ and δ angles, femoro-tibial angle (FTA), and condylar twist angle were assessed. Unpaired t-test, Mann-Whitney U test, and Chi-square test were used to test differences between the good and poor Δflexion groups. Multiple logistic regression examined the association between each factor and the dependent variables (good Δflexion or poor Δflexion). Significant differences in the preoperative knee flexion, postoperative knee flexion, preoperative knee extension, and postoperative knee extension angles, postoperative KOOS pain and activity of daily living, β, ɤ angles were observed between the good and poor Δflexion groups. The model Chi-squared test revealed that the ɤ angle was significantly affected by the Δflexion angle. With the CSRP TKA, flexion insertion of the femoral component was associated with postoperative flexion ROM improvement.

Double-bundle ACL combined with ALL reconstruction for patients at high risk of ACL failure: clinical and radiological results

BackgroundWe investigated whether double-bundle (DB) anterior cruciate ligament (ACL) reconstruction (ACLR) combined with anterolateral ligament reconstruction (ALLR) improved clinical and radiological outcomes in patients at high risk of ACL failure. The primary outcome was graft failure, and secondary outcomes included knee stability and patient-reported outcome measures (PROMs).Patients and methodsFifty-two patients who underwent DB ACLR combined with ALLR were included in this retrospective cohort study. Preoperative risk factors, including femorotibial angle (FTA), lateral tibial slope (LTS), medial tibial slope (MTS), and meniscal tears, were assessed using X-ray and magnetic resonance imaging (MRI). The grade of post-operative pivot shift, Lysholm score, and Tegner activity score were used to assess clinical outcomes. The minimum follow up duration was 2 years.ResultsThe cohort (mean age, 26.1 ± 9.4 years; 51.9% male) had a mean follow-up duration of 28.9 ± 3.4 months. Preoperatively, 57.8% had lateral meniscus (LM) tears, and 61.0% had a grade 2–3 pivot shift. Postoperatively, no graft failures or revision cases occurred during follow-up. Approximately 90.4% of the patients exhibited a negative pivot shift (p < 0.001), with Lysholm and Tegner activity scores of 92.5 ± 6.1 and 5.1 ± 2.0. The medial meniscus (MM) tear group had a significantly smaller FTA than the intact group (p = 0.043). No significant differences in PROMs were found between the LM tear and intact LM groups or between the high and low MTS or LTS groups (p = n.s.).ConclusionDB ACLR combined with ALLR had satisfactory clinical outcomes in patients at high risk of ACL failure, with no graft failures observed during a mean follow-up duration of 2.4 years. The technique effectively reduced the postoperative pivot shift, regardless of preoperative risk factors.Study designLevel IV, retrospective therapeutic case-series.Trail registrationethical approval number, 202300134B0; ethical committee, the Institutional Review Board of Chang Gung Medical Foundation.

Clinical outcomes of total knee arthroplasty for valgus knees caused by hip diseases: Coxitis knees and long leg arthropathies

PurposeCoxitis knees and long leg arthropathies are similar pathological conditions; however, their clinical outcomes after total knee arthroplasty (TKA) have rarely been reported. The present study aimed to investigate clinical outcomes after TKA for these knee conditions, namely valgus knees caused by hip disease. MethodsThis retrospective cohort study included 19 TKAs performed on valgus knees caused by hip osteoarthritis (OA). Two years post-operatively, clinical outcomes, including range of motion and 2011 Knee Society Score (2011KSS), were assessed and were compared with pre-operative values. Pre-operative knee phenotypes, including lateral distal femoral angle and medial proximal tibial angle, were assessed, and their associations with clinical outcomes were investigated. ResultsAll subscales of the 2011KSS improved significantly post-operatively (P ​< ​0.05). There was also a significant improvement in extension post-operatively (P ​< ​0.05). The mean femorotibial angle improved post-operatively from 157.7° to 175.2°(P ​< ​0.05). There were five coxitis knee patients who had knee OA on the ipsilateral side of the hip, and five long leg arthropathy patients who had knee OA on the contralateral side of the hip. ConclusionsSatisfactory clinical outcomes were observed after TKA for valgus knees caused by hip OA, such as coxitis knees and long leg arthropathies.

Assessment of preoperative planning and intraoperative accuracy of the AIKNEE system for total knee arthroplasty

BackgroundThe aim of this retrospective study was to evaluate the effectiveness and accuracy of the AIKNEE system in preoperative planning and intraoperative alignment for total knee arthroplasty (TKA).MethodsA total of 64 patients were planned preoperatively by the AIKNEE system, including the measurement of mechanical femorotibial angle (mFTA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA) using three-dimensional reconstructed images. Intraoperatively, the actual prosthesis size and alignment were compared to the planned parameters. Postoperative outcomes, including pain levels, range of motion (ROM), and Knee Scoring System (KSS) scores, were assessed after surgery. Statistical analyses were performed to evaluate the correlation between alignment deviations and postoperative function.ResultsThe AIKNEE system accurately predicted the prosthesis size in thirty-one of femoral cases (48%) and forty-seven of tibial cases (73%). Deviations of mFTA, LDFA, and MPTA from the target value were within 3° in 88%, 92%, and 95% of cases, respectively. A significant improvement was observed in postoperative pain, ROM, and KSS scores (p < 0.001). Correlation analysis revealed that greater deviations in mFTA and LDFA were associated with increased pain (p = 0.004, 0.047) and lower KSS scores (p = 0.027).ConclusionThe AIKNEE system demonstrated promising results in predicting prosthesis size and achieved alignment within the desired range in a majority of cases. Postoperative outcomes, including pain levels and functional improvement, were favorable.

Relevance of instrumented gait analysis in the prediction of the rebound phenomenon after guided growth intervention

Predictors of rebound after correction of coronal plane deformities using temporary hemiepiphysiodesis (TH) are not well defined. The following research questions were tested: (1) Is the dynamic knee joint load useful to improve rebound prediction accuracy? (2) Does a large initial deformity play a critical role in rebound development? (3) Are BMI and a young age risk factors for rebound? Fifty children and adolescents with idiopathic knee valgus malalignment were included. A deviation of the mechanical femorotibial angle (MFA) of ≥ 3° into valgus between explantation and the one-year follow-up period was chosen to classify a rebound. A rebound was detected in 22 of the 50 patients (44%). Two predictors of rebound were identified: 1. reduced peak lateral knee joint contact force in the first half of the stance phase at the time of explantation (72.7% prediction); 2. minor initial deformity according to the MFA (70.5% prediction). The best prediction (75%) was obtained by including both parameters in the binary logistic regression method. A TH should not be advised in patients with a minor initial deformity of the leg axis. Dynamic knee joint loading using gait analysis and musculoskeletal modeling can be used to determine the optimum time to remove the plates.

Femorotibial angle scan-rescan reproducibility: A high-precision calculation on a large cohort.

Femorotibial angle (FTA) is a convenient measure of coronal knee alignment that can be extracted from a short knee radiograph, avoiding the additional radiation exposure and specialist equipment required for full-leg radiographs. While intra- and inter-reader reproducibility from the same image has been reported, the full scan-rescan reproducibility across images, as calculated in this study, has not. In this study, 4589 FTA measurement pairs from 2586 subjects acquired a year apart were used to estimate FTA scan-rescan reproducibility using data from the Osteoarthritis Initiative. Subjects with radiographic progression of osteoarthritis or other conditions that may cause a change in coronal knee alignment were excluded. Measurement pairs were analysed using paired-samples tests to detect differences and compared to symptomatic changes in Western Ontario and McMaster Universities Arthritis Index scores for joint pain, stiffnessand physical function to detect correlations. The 95% limit of agreement and the paired-samplescorrelation were calculated with high precision to be [-1.76°, +1.78°] and 0.938, considerably worse than the corresponding figures for intra- and inter-reader reproducibility, without relation to symptomatic or radiographic changes in knee condition. This error will weakly attenuate and values from their true values in correlative studies involving FTA. The realistic maximum value for is 87%and for Pearson's is 93%. The scan-rescan reproducibility in FTAis almost double the intra- and inter-reader reliability from a single scan. At almost ±2° accuracy, FTA is inappropriate for surgical use, but it is sufficiently reproducible to produce good correlations in studies predicting disease incidence and progression. Level II, retrospective study.

Influence of different standing positions on anatomical parameters of coronal whole-leg weight-bearing radiographs in preoperative planning for high tibial osteotomy.

The purpose of this study was to assess the differences in lower limb global alignment and anatomical parameters of coronal whole-leg radiographs, which were generally used in preoperative planning for high tibial osteotomy (HTO), according to different weight-bearing standing positions. Between April 2021 and December 2022, 176 patients (60 males and 116 females) were investigated. Full-weight-bearing coronal whole-leg radiographs were obtained with the patella centred on the femoral condyle. Patients were divided by Kellgren-Lawrence grade (KL-0, KL-I, KL-II and KL-III) and assessed in two standing positions: legs closed and legs spread. Patients with flexion contractures or those unable to stand with full weight bearing were excluded. The mechanical distal femoral angle, medial proximal tibial angle (MPTA), femorotibial angle, joint line convergence angle, percentage weight-bearing line (%WBL) and hip-knee-ankle angle (HKAA) were measured. The Student's t test was used to compare the two standing positions. A p value < 0.05 indicated a statistically significant difference. The MPTAs of legs closed standing and legs spread standing were 84.9 ± 2.6° and 85.1 ± 2.4° in KL-0, 84.7 ± 2.0° and 84.9 ± 2.1° in KL-I and 85.0 ± 2.43° and 85.4 ± 2.4° in KL-II, respectively. There were statistically significant differences in the MPTA between the two standing positions in KL-0, KL-I and KL-II. In contrast, the %WBL and HKAA did not change regardless of the standing position. In the KL-III group, no statistical significance was observed for any of the anatomical parameters. Several anatomical parameters were changed between the legs closed standing and the legs spread standing positions. It was suggested that the standing position should be taken into consideration in the planning for HTO. Level IV, Case series with no comparison group.

Superior accuracy in knee double level osteotomy using a novel hybrid fixation technique compared to conventional double plating.

This study aimed to compare two different double-level knee osteotomy (DLO) fixation techniques. The primary outcome reported the radiological coronal plane correction and its accuracy. The secondary outcomes reported the correction outliers, the clinical outcomes, the 5-year postoperative satisfaction and the complications. A retrospective review of a single surgeon osteotomy database identified 52 cases of DLO between 2011 and 2019, of which 24 cases met the inclusion criteria. Patients were categorised into two groups: the nail-plate (NP) group fixed with a magnetic extendable intramedullary tibial nail and femoral conventional plate, and the double-plate (DP) group fixed with conventional plates (tibia and femur). Radiographic parameters were recorded, including the mechanical femorotibial angle (mFTA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle (mLDFA), joint line convergence angle (JLCA) and weight-bearing line ratio (Mikulicz %). Surgical accuracy was calculated as the difference between the achieved and the planned correction. Outliers were defined as those with a greater than 10% difference from the planned correction. Simple knee value scores and visual analogue scale for pain were recorded preoperatively and postoperatively at 2 and 5 years. Five-year patient satisfaction was recorded. A total of 24 patients were included: the NP group (n = 12) and the DP group (n = 12). Significant coronal plane corrections were achieved in the NP group for the mean mFTA (preoperative 167.9° ± 3.4° to postoperative 182.1° ± 1.4°), the mean MPTA (preoperative 83.5° ± 2.9° to postoperative 91.3° ± 2.8°) and the mean mLDFA (preoperative 89.8° ± 3.4° to postoperative 85.9° ± 4.4°). Similarly, significant coronal plane corrections were achieved in the DP group for the mean mFTA (preoperative 168.6° ± 4.4° to postoperative 182.2° ± 2°), the mean MPTA (preoperative 84.2° ± 2° to postoperative 88.3° ± 4.1°) and the mean mLDFA (preoperative 90.7° ± 2.9° to postoperative 83.9° ± 1.7°) (all p < 0.05). The mean correction accuracy was higher for the NP versus DP group at 3.4 ± 3.4% versus 7.1 ± 3.9% (intergroup p < 0.05). There were no outliers in the NP group versus two outliers (overcorrected) (16.7%) in the DP group. Significant clinical improvement was reported in both groups at 2 and 5 years postoperatively (all p < 0.05). Superior correction accuracy and no outliers were achieved in hybrid fixation double-level knee osteotomy compared to the conventional double-plating technique. The magnetic extendable nail offers the advantage of fine-tuning the correction postoperatively and could be a potential research template for future designs of postoperative correction implants. Level III, retrospective cohort study.

Femorotibial angle on short knee radiographs fails to accurately predict the lower limb mechanical alignment. A systematic review and meta-analysis on different femorotibial angle definitions and short knee radiograph types.

Hip-knee-ankle angle (HKA) on Full Limb Radiographs (FLRs) is the gold standard for coronal knee alignment assessment. Despite the widespread utilization of the more convenient femorotibial angle (FTA) on either antero-posterior (AP) or postero-anterior (PA) short knee radiographs (SKRs), its definition and correlation with HKA remains controversial. This review is the first to systematically investigate FTA-HKA correlation and the effect of different FTA methods and SKRs. Systematic literature search (Pubmed, Scopus, Cochrane Library) followed PRISMA guidelines, to evaluate studies examining the FTA-HKA correlation. Meta-analyses compared the 3 most common FTA methods, knee center determination method and SKR types. 17 studies (2597 patients, 3234 knees) were included. The strongest correlation with HKA (r = 0.78) was found for FTA Method 1 (angle formed by lines drawn from the midpoint of tibial spines to points 10 cm above and below the joint line). No significant differences were observed when grouping the FTA methods by knee center assessment (Group I, r = 0.78; Group II, r = 0.77). AP SKRs showed a trend towards stronger FTA-HKA correlation compared to PA SKRs, in both Method 1 (r = 0.79 vs 0.75) and Method 3 (r = 0.80 vs 0.66). Irrespective of its definition or type of SKR used, FTA lacks reliable accuracy in predicting the HKA in most knees. FLRs should be used whenever precise estimation of the patient's alignment is necessary. Caution is warranted in interpreting studies investigating knee alignment or knee arthroplasty outcomes based on FTA.

Medial cortical bone thickness of the tibial diaphysis in osteoarthritis is related to lower extremity alignment and tibial morphology

BackgroundThe purpose of this study was to clarify (1) the differences in cortical bone thickness (CBT) of the tibial diaphysis between healthy and osteoarthritic knees and (2) the influences of the femorotibial angle (FTA) and inclination of the medial compartment of the proximal tibia (MCT) on tibial CBT.MethodsThe study assessed 60 subjects with varus knee osteoarthritis (OA) (22 males and 38 females; mean age, 74 ± 7 years) and 53 healthy elderly subjects (28 males and 25 females; mean age, 70 ± 6 years). Three-dimensional estimated CBT of the tibial diaphysis was automatically calculated for 2752–11,296 points using high-resolution measurements from CT. The standardized CBT was assessed in 24 regions by combining six heights and four areas. Additionally, the association between the CBT, each FTA, and MCT inclination was investigated.ResultsThe OA group showed a thicker CBT in the medial areas than in the lateral areas of the proximal tibia, while the healthy group had a thicker lateral CBT. The medial-to-lateral ratio of the proximal tibia was significantly higher in the OA group than in the healthy group. The proximal-medial CBT correlated with FTA and MCT inclinations in the OA group.ConclusionsThis study demonstrated that varus osteoarthritic knees showed a different trend of proximal-medial CBT with associations in FTA and MCT inclination from healthy knees, possibly due to medial load concentration.

Limitations of the knee society score in kinematically aligned total knee arthroplasty.

The Knee Society Scoring System (KSS) is a frequently used outcome score which quantifies functional patients' outcomes before and after total knee arthroplasty (TKA). Several problems arise when trying to implement KSS for obtaining postoperative outcomes after more personalised aligned TKAs. Scoring for valgus femorotibial angle (FTA) intervals outside moderate ranges is often poorly explained, the specific version of KSS used for outcome collection is frequently unclear and the exact measuring methods are typically not described in the literature. The aims of this systematic review were to investigate the latest user practice, the application of KSS and its limitations after kinematically aligned (KA) TKA. A systematic literature search following PRISMA guidelines was conducted on PubMed, Embase, Medline and Scopus to identify potentially relevant articles for this review, published from the beginning of January 2013 until the end of January 2023. Broad Mesh terms such as 'kinematic alignment', 'total knee arthroplasty' and 'knee society score' were used for building search strategy in each database accordingly. Articles reporting postoperative values of the objective surgeon-assessed KSS after KA TKA or KA and mechanically aligned TKA were included. For assessing included randomised control trials (RCTs), an Agency for Healthcare Research and Quality's design-specific scale for assessing RCTs was used. The non-RCTs were assessed by using the Joanna Briggs Institute Critical Appraisal Tool. The Ottawa-Newcastle Score system was also used. Studies were additionally evaluated for their radiological methodology by using a five-question checklist (Radiological Assessment Qualit criteria). The initial search identified 167 studies, of which 129 were considered for screening. Ten studies reporting outcomes after KA TKA did not use the objective surgeon-assessed part of KSS for clinical outcome measurement, and 30 studies reporting outcomes after KA TKA did not use KSS at all for clinical and/or functional outcomes. From the 10 included studies, only six have used the latest KSS score (2011), the rest using its 1989 variant; and out of these six studies, only two presented values of the FTA, which is needed for calculating the KSS's 'alignment' subcomponent, the rest presenting hip-knee-ankle angle (HKA) values. Additionally, when converting these HKA values to FTA intervals, the authors of this systematic review found that KA TKA FTA intervals display limits, which tend to be outside the 'well-scored' KSS anatomical alignment interval. The inconsistent and nonstandardised use of the surgeon-assessed KSS across studies reviewed compromises assessment reliability and patient outcome scores. To enhance precision and comparability, it is crucial to standardise the KSS application, incorporating personalised alignment strategies for more accurate patient evaluations. Level III.

Total knee arthroplasty following lateral closing-wedge high tibial osteotomy versus primary total knee arthroplasty: a propensity score matching study

BackgroundThe disparity in patient-reported outcomes between total knee arthroplasty (TKA) following high tibial osteotomy (HTO) and primary TKA has yet to be fully comprehended. This study aims to compare the patient-reported outcomes, radiological parameters and complication rates between TKA following HTO and primary TKA.MethodsSixty-five patients who underwent TKA following lateral closing-wedge HTO were compared to a matched group of primary TKA at postoperative 6-months and 1-year. Between-group confounders of age, gender, smoking status, Body Mass index, preoperative Numeric Rating Scale (NRS) pain in rest, Knee injury and Osteoarthritis Outcome Score-Physical function Shortform (KOOS-PS), EuroQol five-dimensional (EQ-5D) overall health score, and Oxford Knee Score (OKS) were balanced by propensity score matching. Patient-reported outcome measures were NRS pain in rest, KOOS-PS, EQ-5D overall health score, and OKS. Radiological parameters were femorotibial angle, medial proximal tibial angle, anatomical lateral distal femoral angle, posterior tibial slope, and patellar height assessed by Insall-Salvati ratio. The complication rates of TKA were compared between the two groups. The HTO survival time, the choice of staple removal before or during TKA in patients who underwent TKA following HTO patients, and the rate of patellar resurfacing were assessed. The p value < 0.0125 indicates statistical significance after Bonferroni correction.ResultsAfter propensity score matching, no significant between-group differences in the patient-reported outcome measures, radiographical parameters and complication rates were found (p > 0.0125). In the TKA following HTO group, with an average HTO survival time of 8.7 years, staples were removed before TKA in 46 patients (71%) and during TKA in 19 patients, and 11 cases (17%) had patella resurfacing. In the primary TKA group, 15 cases (23%) had patella resurfacing.ConclusionThe short-term assessment of TKA following HTO indicates outcomes similar to primary TKA. A previous HTO does not impact the early results of subsequent TKA, suggesting that the previous HTO has minimal influence on TKA outcomes.Level of evidenceIII, cohort study.

Impact of postoperative femorotibial axis on functional outcomes in unicompartmental knee arthroplasty.

This study aimed to compare the functional outcomes of patients undergoing fixed-bearing medial unicompartmental knee arthroplasty (UKA) classified as either varus or neutral based on their postoperative femorotibial angle (FTA), with the goal of evaluating the impact of FTA on functional results. A total of 38 knees of 35 patients (27 females, 8 males; mean age: 63.6±7.1 years; range, 52 to 75 years) were included in this retrospective study. The data was collected between December 15, 2020, and January 15, 2021. Patients were categorized into two groups based on their postoperative FTA. The neutral group consisted of patients with an FTA range of 5.1° to 7.4°, while the varus group included patients with an FTA range of 0.1° to 4.8°. Knee Outcome Osteoarthritis Score (KOOS), Visual Analog Scale (VAS) scores, sit to stand test results, and six minute walk test data were analyzed. The mean follow-up was 42.0±19.3 months. The postoperative VAS score for the varus group was 0.95±0.99, whereas the neutral group had a VAS score of 2.19±1.83 (p=0.021). The mean KOOS for the varus group was 88.01±7.88, whereas the neutral group had a mean KOOS score of 78.46±13.69 (p=0.006). In patients undergoing UKA, mild varus alignment could yield superior early and midterm functional outcomes compared to a neutral femorotibial angle.

Bone substitute fracture in open wedge high tibial osteotomy: Comparison of two different bone substitutes

PurposeThe aim of this study was to retrospectively compare bone substitute fracture patterns and outcomes in patients who underwent open wedge high tibial osteotomy (OWHTO) with OSferion60 or OSferion60 Marvelous bone substitutes. Patients with and without bone substitute fractures were compared and risk factors for bone substitute fracture were identified. MethodsIncluded patients were physically active non-smokers with knee osteoarthritis and deformity in the proximal tibia, persistent pain, and <5° of flexion contracture. OWHTO was performed with a TriS plate and a target femorotibial angle (FTA) of 170°. Full weight-bearing began the day after surgery. Pre-, intra-, and post-operative evaluations of demographic, clinical, and radiological factors were performed. Regression analysis was performed to identify risk factors for bone substitute fracture. ResultsData for 63 patients were analyzed (OSferion60, n ​= ​28 and Marvelous, n ​= ​35; bone substitute fracture, n ​= ​32 and non-bone substitute fracture, n ​= ​31). No significant differences were found between the bone substitute groups in patient characteristics and pre-operative and 2-year FTA, Japanese Orthopaedic Association (JOA) score, and flexion range. FTA and JOA scores improved significantly 2 years post-operatively (both p ​< ​0.001). There were 32 bone substitute fractures (OSferion60, n ​= ​20; Marvelous, n ​= ​12); all occurred by the 1-month follow-up. Gap filling occurred significantly earlier in the Marvelous group versus the OSferion60 group (p ​< ​0.001). Risk factors for bone substitute fracture were weaker bone substitute [odds ratio (OR) ​= ​8.34; p ​< ​0.001] and lateral hinge fracture (OR ​= ​11.7; p ​= ​0.045). ConclusionsAlthough bone substitute fracture was common in both bone substitute groups, this did not affect outcomes. However, lateral hinge fractures are a particular concern.