Varus alignment of the proximal tibia is associated with structural progression in early to moderate varus osteoarthritis of the knee

Preoperative Medial Meniscus Extrusion on Magnetic Resonance Imaging Is Associated With a Tendency Toward Varus Shifting of Open-Wedge High Tibial Osteotomy: A Minimum 5-Year Follow-Up Study

PURPOSE

To investigate serial changes in postoperative alignment over 5 years after open-wedge high tibial osteotomy (OWHTO) and to identify risk factors associated with alterations in the postoperative weightbearing line (WBL) ratio.

METHODS

Patients who underwent OWHTO during 2011-2017 were retrospectively reviewed. The inclusion criteria were (1) follow-up duration ≥5 years and (2) serial postoperative longstanding hip-to-ankle radiographs to evaluate alignment alterations. The WBL ratio was measured preoperatively and at 3 months, 6 months, 1 year, and 5 years postoperatively to evaluate serial changes. Alterations in the WBL ratio were analyzed using a linear mixed model, considering potential risk factors including International Cartilage Repair Society grades of each compartment and medial meniscus extrusion (≥3 mm). Clinical outcomes were assessed using the Knee Society objective and functional scores, and the correlations between clinical outcomes and alignment alteration were examined.

RESULTS

A total of 78 knees were investigated. During the study period, the overall WBL ratio decreased by 5.5% ± 7.2%, signifying varus shifting, from 58.6% ± 11.5% at 3 months postsurgery to 51.5% ± 12.7% at 5 years postsurgery. Based on univariate regression analyses, International Cartilage Repair Society grades of the medial compartment and medial meniscus extrusion were included in a linear mixed model regarding alignment alteration. The model identified medial meniscus extrusion as a significant risk factor after adjusting for time (P < .001). Medial meniscus extrusion also had a significant interaction with time (P < .001), indicating greater alignment alteration in cases of medial meniscus extrusion. The extrusion was noted in 68 of 78 knees.

CONCLUSIONS

In the midterm following OWHTO, the overall alignment had a tendency toward varus shifting. A linear mixed model found that preoperative medial meniscus extrusion on magnetic resonance imaging is associated with the tendency.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The Effect of Lower Limb Alignment on Tibiofemoral Joint Contact Biomechanics after Medial Meniscus Posterior Root Repair: A Finite-Element Analysis

INTRODUCTION

The purpose of this study was to determine how variations in lower limb alignment affect tibiofemoral joint contact biomechanics in the setting of medial meniscus posterior root tear (MMPRT) and associated root repair.

METHODS

A finite-element model of an intact knee joint was developed. Limb alignments ranging from 4° valgus to 8° varus were simulated under a 1,000 N compression load applied to the femoral head. For the intact, MMPRT, and root repair conditions, the peak contact pressure (PCP), total contact area, mean and maximum local contact pressure (LCP) elevation, and total area of LCP elevation of the medial tibiofemoral compartment were quantified.

RESULTS

The PCP and total contact area of the medial compartment in the intact knee increased from 2.43 MPa and 361 mm 2 at 4° valgus to 9.09 MPa and 508 mm 2 at 8° of varus. Compared with the intact state, in the MMPRT condition, medial compartment PCP was greater and the total contact area smaller for all alignment conditions. Root repair roughly restored PCPs in the medial compartment; however, this ability was compromised in knees with increasing varus alignment. Specifically, elevations in PCP relative to the intact state increased with increasing varus, as did the total contact area with LCP elevation. After root repair, medial compartment PCP remained elevated above the intact state at all degrees tested, ranging from 0.05 MPa at 4° valgus to 0.27 MPa at 8° of varus, with overall PCP values increasing from 2.48 to 9.09 MPa. For varus alignment greater than 4°, root repair failed to reduce the total contact area with LCP elevation relative to the MMPRT state.

DISCUSSION

Greater PCPs and areas of LCP elevation in varus knees may reduce the clinical effectiveness of root repair in delaying or preventing the development of tibiofemoral osteoarthritis.

Medial opening wedge high tibial osteotomy for the treatment of medial unicompartmental knee osteoarthritis: A state-of-the-art review

Medial unicompartmental knee osteoarthritis is a common condition that is frequently associated with significant pain and dysfunction. Medial opening wedge high tibial osteotomy (MOWHTO) offers a unique opportunity to preserve the knee joint and potentially alter the course of the degenerative process. Recent advances in this field of surgery have enabled surgeons to perform a MOWHTO in a safe, reliable and reproducible manner. This state-of-the-art review highlights the most important advances in the field of MOWHTO. Key concepts related to patient selection, pre-operative planning, surgical accuracy and patient outcome are considered. The importance of an individualized approach is emphasized and its influence on the future direction of the procedure is discussed.

Automated Radiographic Measurements of Knee Osteoarthritis

OBJECTIVE

Herewith, we report the development of Orthopedic Digital Image Analysis (ODIA) software that is developed to obtain quantitative measurements of knee osteoarthritis (OA) radiographs automatically. Manual segmentation and measurement of OA parameters currently hamper large-cohort analyses, and therefore, automated and reproducible methods are a valuable addition in OA research. This study aims to test the automated ODIA measurements and compare them with available manual Knee Imaging Digital Analysis (KIDA) measurements as comparison.

DESIGN

This study included data from the CHECK (Cohort Hip and Cohort Knee) initiative, a prospective multicentre cohort study in the Netherlands with 1,002 participants. Knee radiographs obtained at baseline of the CHECK cohort were included and mean medial/lateral joint space width (JSW), minimal JSW, joint line convergence angle (JLCA), eminence heights, and subchondral bone intensities were compared between ODIA and KIDA.

RESULTS

Of the potential 2,004 radiographs, 1,743 were included for analyses. Poor intraclass correlation coefficients (ICCs) were reported for the JLCA (0.422) and minimal JSW (0.299). The mean medial and lateral JSW, eminence height, and subchondral bone intensities reported a moderate to good ICC (0.7 or higher). Discrepancies in JLCA and minimal JSW between the 2 methods were mostly a problem in the lateral tibia plateau.

CONCLUSIONS

The current ODIA tool provides important measurements of OA parameters in an automated manner from standard radiographs of the knee. Given the automated and computerized methodology that has very high reproducibility, ODIA is suitable for large epidemiological cohorts with various follow-up time points to investigate structural progression, such as CHECK or the Osteoarthritis Initiative (OAI).

Comparison of both lower leg bone mineral density in single limb knee osteoarthritis patients

PURPOSE

The relationship between knee osteoarthritis (OA), bone mineral density (BMD), and alignment has not yet been clarified. This study aimed to investigate the relationship between the two limbs in patients with single-limb knee OA.

METHODS

Patients who underwent single-limb total knee arthroplasty between March 2019 and February 2021 were retrospectively analyzed. Only patients with Kellgren-Lawrence (KL) grades III and IV on the operated side and KL I and II on the opposite side were included. Patients with traumatic OA, a surgery that could change the alignment of both lower extremities and previous fractures were excluded. The proximal femur BMD on the OA and non-OA sides were compared. In addition, the difference in BMD was compared between a group with a difference in alignment of both lower extremities (> 5°) and a group without a difference (< 5°).

RESULTS

In total, 149 patients were included. The BMD T-score of the femoral neck on the OA side was lower than that of the non-OA side (p < 0.001). There was no correlation between BMD and alignment, and there was no difference in BMD according to the difference in alignment.

CONCLUSION

The femoral neck BMD of the leg on the side with knee OA was lower than that on the side without OA. However, the alignment difference between the legs did not affect BMD. BMD was lowered because of OA and not because of alignment.

Greater medial proximal tibial slope is associated with bone marrow lesions in middle-aged women with early knee osteoarthritis

BACKGROUND

Bone marrow lesion (BML) is an important magnetic resonance finding (MRI) finding that predicts knee osteoarthritis. The purpose of this study was to investigate the influence of proximal tibial morphology on BML, including the spreading root sign (SRS), in women without radiographic knee osteoarthritis (OA). It was hypothesized that varus alignment and a greater posterior tibial slopes (PTS) are associated with BML.

MATERIALS AND METHODS

A total of 359 female volunteers without knee OA who were participants in the Iwaki Health Promotion Project in 2017 or 2019 were enrolled. Participants were divided into the non-OA and early knee OA (EKOA) groups based on the Luyten's classification criteria. The presence of pathological cartilage lesions, BMLs, attritions, meniscal lesions and effusions was scored on T2-weighted fat-suppressed magnetic resonance imaging (MRI) according to the Whole-Organ MRI Scoring system. The medial proximal tibial angle (MPTA) and medial and lateral PTS (MPTS and LPTS, respectively) were measured. Regression and receiver operating characteristic (ROC) analyses were performed to reveal the relationship between BMLs and proximal tibial morphological parameters.

RESULTS

Of the 359 participants, 54 (15%) were classified as having EKOA. The prevalence of cartilage lesions, BMLs, attritions, meniscal lesions and effusions was higher in the EKOA group than in the non-OA group. The two groups had no significant difference in the proximal tibial parameters. Regression analysis revealed that age and a smaller MPTA were associated with BML in both groups. Attrition (p = 0.029) and the MPTS (p = 0.025) were positively associated with BML in the EKOA group.

CONCLUSION

The prevalence of BMLs was higher in women with EKOA and correlated with the varus and greater posterior slopes in those without radiographic knee OA.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Joint line obliquity after lateral closing-wedge high tibial osteotomy does not adversely affect clinical and radiological outcome: a 5-year follow-up study

PURPOSE

To analyze the association between change in knee joint line obliquity (KJLO) and patient-reported outcome, radiological progression of osteoarthritis, and surgical survival after lateral closing-wedge high tibial osteotomy (HTO).

METHODS

A cohort of 180 patients treated in one single hospital with lateral closing-wedge HTO was examined. KJLO was defined by the medial proximal tibial angle (MPTA). To assess the association between KJLO and patient-reported outcome, radiological progression of osteoarthritis, and surgical survival, patient groups were defined: I, postoperative MPTA < 95.0°; II, postoperative MPTA ≥ 95.0°; A, MPTA change < 8.0°; B, MPTA change ≥ 8.0°. Propensity score matching was used for between-groups (I and II, A and B) covariates matching, including age, gender, preoperative lower limb alignment, preoperative medial joint space width (mJSW), preoperative Western Ontario and McMaster Universities osteoarthritis Index (WOMAC) score, wedge size, and postoperative follow-up time. Patient-reported outcome was assessed by the WOMAC questionnaire, radiological progression of osteoarthritis by mJSW and Kellgren-Lawrence (KL) grade progression (≥ 1) preoperatively and at follow-ups (> 2 years). Failure was defined as revision HTO or conversion to knee arthroplasty.

RESULTS

After propensity score matching, groups I and II contained 58 pairs of patients and groups A and B contained 50 pairs. There were no significant differences in postoperative WOMAC score or surgical failure rate between groups I and II or between groups A and B (p > 0.05). However, the postoperative mJSW was significantly lower in group I than group II (3.2 ± 1.6 mm vs 3.9 ± 1.8 mm; p = 0.018) and in group A than group B (3.0 ± 1.7 mm vs 3.7 ± 1.5 mm; p = 0.040). KL grade progression rate was significantly higher in group I than group II (53.4% vs 29.3%; p = 0.008) and in group A than group B (56.0% vs 28.0%; p = 0.005).

CONCLUSION

Increased KJLO (postoperative MPTA ≥ 95.0°) or MPTA change ≥ 8.0° after lateral closing-wedge HTO does not adversely affect patient-reported outcome, radiological progression of osteoarthritis, or surgical survival at an average 5-year follow-up.

LEVEL OF EVIDENCE

III, retrospective cohort study.

DeepKOA: a deep-learning model for predicting progression in knee osteoarthritis using multimodal magnetic resonance images from the osteoarthritis initiative

Background

No investigations have thoroughly explored the feasibility of combining magnetic resonance (MR) images and deep-learning methods for predicting the progression of knee osteoarthritis (KOA). We thus aimed to develop a potential deep-learning model for predicting OA progression based on MR images for the clinical setting.

Methods

A longitudinal case-control study was performed using data from the Foundation for the National Institutes of Health (FNIH), composed of progressive cases [182 osteoarthritis (OA) knees with both radiographic and pain progression for 24-48 months] and matched controls (182 OA knees not meeting the case definition). DeepKOA was developed through 3-dimensional (3D) DenseNet169 to predict KOA progression over 24-48 months based on sagittal intermediate-weighted turbo-spin echo sequences with fat-suppression (SAG-IW-TSE-FS), sagittal 3D dual-echo steady-state water excitation (SAG-3D-DESS-WE) and its axial and coronal multiplanar reformation, and their combined MR images with patient-level labels at baseline, 12, and 24 months to eventually determine the probability of progression. The classification performance of the DeepKOA was evaluated using 5-fold cross-validation. An X-ray-based model and traditional models that used clinical variables via multilayer perceptron were built. Combined models were also constructed, which integrated clinical variables with DeepKOA. The area under the curve (AUC) was used as the evaluation metric.

Results

The performance of SAG-IW-TSE-FS in predicting OA progression was similar or higher to that of other single and combined sequences. The DeepKOA based on SAG-IW-TSE-FS achieved an AUC of 0.664 (95% CI: 0.585-0.743) at baseline, 0.739 (95% CI: 0.703-0.775) at 12 months, and 0.775 (95% CI: 0.686-0.865) at 24 months. The X-ray-based model achieved an AUC ranging from 0.573 to 0.613 at 3 time points. However, adding clinical variables to DeepKOA did not improve performance (P>0.05). Initial visualizations from gradient-weighted class activation mapping (Grad-CAM) indicated that the frequency with which the patellofemoral joint was highlighted increased as time progressed, which contrasted the trend observed in the tibiofemoral joint. The meniscus, the infrapatellar fat pad, and muscles posterior to the knee were highlighted to varying degrees.

Conclusions

This study initially demonstrated the feasibility of DeepKOA in the prediction of KOA progression and identified the potential responsible structures which may enlighten the future development of more clinically practical methods.

Simulating Knee-Stress Distribution Using a Computed Tomography-Based Finite Element Model: A Case Study

This study aimed to evaluate the mechanism of progression involved in knee osteoarthritis (OA). We used the computed tomography-based finite element method (CT-FEM) of quantitative X-ray CT imaging to calculate and create a model of the load response phase, wherein the greatest burden is placed on the knee joint while walking. Weight gain was simulated by asking a male individual with a normal gait to carry sandbags on both shoulders. We developed a CT-FEM model that incorporated walking characteristics of individuals. Upon simulating changes owing to a weight gain of approximately 20%, the equivalent stress increased extensively in both medial and lower leg aspects of the femur and increased medio-posteriorly by approximately 230%. As the varus angle increased, stress on the surface of the femoral cartilage did not change significantly. However, the equivalent stress on the surface of the subchondral femur was distributed over a wider area, increasing by approximately 170% in the medio-posterior direction. The range of equivalent stress affecting the lower-leg end of the knee joint widened, and stress on the posterior medial side also increased significantly. It was reconfirmed that weight gain and varus enhancement increase knee-joint stress and cause the progression of OA.

[Developments in Research on the Relationship Between Matrix Metalloproteinases and Osteoarthritis]

Matrix metalloproteinases (MMPs) acquired their names because they depend on metal ions such as Ca 2+ and Zn 2+ as their cofactors. Members of this family of proteins share a similar structure consisting of five functionally distinct structural domains. MMPs, including MMP-1, MMP-3, MMP-9, and MMP-13, are key substances that promote cartilage matrix degradation and play an important role in the occurrence and progression of osteoarthritis (OA). MMPs boost the development of OA through the degradation of extracellular matrix proteins of chondrocytes, the promotion of inflammation, and other mechanisms, and are hence attracting extensive and increasing attention from the medical community. OA is a common degenerative disease that occurs in the joints and is associated with aging, metabolism, infections, genetics, exercise, and other predisposing factors. The pathological changes it causes can lead to a series of clinical symptoms such as joint pain, morning stiffness, and restricted joint movement, severely affecting patients' quality of life. The pathogenic mechanism of this highly prevalent disease is still unclear. At present, there is no effective treatment available for disease improvement. In the future, selective inhibition of MMPs, the key enzymes, may become an effective therapeutic approach. Focusing on the pathogenic effects of MMPs in OA, we herein reviewed the latest findings on the role of MMPs in the occurrence and progression of OA.

Anatomical Imaging Study on Uneven Settlement of the Proximal Tibia

OBJECTIVE

Uneven settlement of the proximal tibia significantly contributes to the onset and progression of medial compartment knee OA; however, the specific location and variations of proximal tibial deformity remain unclear. Therefore, this study aimed to explore the effects of the anatomic morphology of different tibial regions on proximal tibial vara and proximal tibial microstructural changes with age in both sexes to reveal the pattern of uneven settlement of the proximal tibia.

METHODS

In this retrospective study, we reviewed the radiographs of 414 patients (789 legs) between May and September 2021. The medial proximal tibial angle (MPTA) and four anatomic angles of the tibia (i.e., the tibial plateau-epiphyseal line [PT-EL] angle, epiphyseal line-tibial platform [EL-PF] angle, epiphyseal axis inclination angle [EAIA], and subepiphyseal axis inclination angle [SAIA]) were measured. The effect of each angle on MPTA and their changes with age in both sexes were investigated using Pearson's correlation coefficient and multiple linear regression.

RESULTS

In females, PT-EL angle, EL-PF angle, and SAIA negatively correlated with MPTA (r = -0.325, -0.246, and -0.502; p < 0.05), and EAIA positively correlated with MPTA (r = 0.099, p < 0.05). Regression analysis showed that the correlations between MPTA and PT-EL angle, EL-PF angle, and SAIA were significant (β = -1.003, -0.013, and -0.971; adjusted R2  = 0.979). Furthermore, MPTA negatively correlated with age (r = -0.202, p < 0.05); PT-EL angle and EAIA positively correlated with age (r = 0.237 and 0.142, p < 0.05). Regression analysis showed that only the correlation between PT-EL angle and age was significant (β = 5.635, p < 0.05). In males, PT-EL angle, EL-PF angle, and SAIA negatively correlated with MPTA (r = -0.270, -0.267, and -0.533; p < 0.05), and EAIA positively correlated with MPTA (r = 0.135, p < 0.05). Regression analysis showed that the correlations between MPTA and PT-EL angle, EL-PF angle, and SAIA were significant (β = -0.992, -0.017, and -0.958; adjusted R2  = 0.970). However, there was no significant correlation between age and any of the measured angles (p > 0.05).

CONCLUSIONS

Proximal tibial vara is affected by the anatomic morphology of the epiphyseal and subepiphyseal regions. In females, the uneven settlement of the epiphysis progresses with age and may be responsible for dynamic varus deformity of the proximal tibia.

Visual Inspection for Lower Limb Malalignment Diagnosis Is Unreliable

OBJECTIVE

Visual inspection of the lower limb is often part of standard clinical practice during a physical examination at the outpatient clinic. This study aims to investigate how reliable visual inspections are in terms of detecting lower limb malalignments without additional tools and physical examinations.

DESIGN

This study enrolled 50 patients. Each patient underwent a whole leg radiograph (WLR); in addition, a standardized digital photograph was taken of the lower limbs. Four persons (different experience levels) visually rated the digital photograph twice (unaware of the hip knee angle [HKA] on the WLR) and placed them in the category: severe valgus (>5°); moderate valgus (2°-5°); neutral, moderate varus (2°-5°); and severe varus (>5°). Visual ratings were compared with the measured HKA on WLRs for correlation using Spearman's rho. Linear ordinal regression models with significance when P < 0.05 were used to test whether body mass index (BMI), age, gender, and HKA were possible risk factors for incorrect visual HKA assessment.

RESULTS

Spearman's rho between the visual assessment and measured HKA on the WLR was moderate with 0.478 (P < 0.01). Women had an increased odds ratio of 3.7 (P = 0.001) for incorrect visual assessment. Higher HKA also increased the odds ratio for erroneous visual assessment with 1.4 (P = 0.003). BMI and age did not significantly increase the odds of erroneous visual leg axis assessments in this study.

CONCLUSIONS

Visual assessment of the lower limb alignment does not provide clinically relevant information. Lower limb malalignment diagnoses cannot be performed using only a visual inspection. Physical examination tests and radiographical assessments are advised.

LEVEL OF EVIDENCE

Diagnostic level II.

Defining and predicting radiographic knee osteoarthritis progression: a systematic review of findings from the osteoarthritis initiative

PURPOSE

The purposes of this systematic review were to (1) identify the commonly used definitions of radiographic KOA progression, (2) summarize the important associative risk factors for disease progression based on findings from the OAI study and (3) summarize findings from radiographic KOA progression prediction modeling studies regarding the characterization of progression and outcomes.

METHODS

A systematic review was performed by conducting a literature search of definitions, risk factors and predictive models for radiographic KOA progression that utilized data from the OAI database. Radiographic progression was further characterized into "accelerated KOA" and "typical progression," as defined by included studies.

RESULTS

Of 314 studies identified, 41 studies were included in the present review. Twenty-eight (28) studies analyzed risk factors associated with KOA progression, and 13 studies created or validated prediction models or risk calculators for progression. Kellgren-Lawrence (KL) grade based on radiographs was most commonly used to characterize KOA progression (50%), followed by joint space width (JSW) narrowing (32%) generally over 48 months. Risk factors with the highest odds ratios (OR) for progression included periarticular bone mineral density (OR 10.40), any knee injury within 1 year (OR 9.22) and baseline bone mineral lesions (OR 7.92). Nine prediction modeling studies utilized both clinical and structural risk factors to inform their models, and combined models outperformed purely clinical or structural models.

CONCLUSION

The cumulative evidence suggests that combinations of structural and clinical risk factors may be able to predict radiographic KOA progression, particularly in patients with accelerated progression. Clinically relevant and feasible prediction models and risk calculators may provide valuable decision-making support when caring for patients at risk of KOA progression, although standardization in modeling and variable identification does not yet exist.

β2-Adrenergic receptor expression in subchondral bone of patients with varus knee osteoarthritis

An important causative factor in osteoarthritis (OA) is the abnormal mechanical stress-induced bone remodeling of the subchondral bone. β2-adrenergic receptor (Adrb2) plays a major role in mechanical stresses that induce bone remodeling. The medial tibial plateau (MTP) and lateral tibial plateau (LTP) of patients with varus Knee osteoarthritis (KO) bear different mechanical stresses. The present study aimed to investigate the expression of Adrb2 in medial tibial plateau subchondral bone (MTPSB) and lateral tibial plateau subchondral bone (LTPSB) in patients with varus KO. A total of 30 tibial plateau samples from patients undergoing total knee arthroplasty for varus KO and MTPSB and LTPSB were studied. Statistical analysis was performed using paired sample t-tests. Safranin O-Fast Green staining and Micro-computed tomography showed significant differences in the bone structure between MTPSB and LTPSB. Tartrate-resistant acid phosphatase (TRAP)-positive cell density in MTPSB was higher than that in LTPSB. Immunohistochemistry, reverse transcription-quantitative polymerase chain reaction, and Western blot analysis revealed that compared to LTPSB, the levels of Adrb2, tyrosine hydroxylase (TH), and osteocalcin increased significantly in MTPSB. Double-labeling immunofluorescence showed Adrb2 was present in the majority of TRAP-positive multinuclear cells of the MTPSB. The expression of Adrb2 and TH was significantly higher in MTPSB than in LTPSB, confirming the involvement of these molecules in the development of OA.

Prevalence of proximal tibia vara in Indonesian population with knee osteoarthritis

BACKGROUND

Proximal tibia vara has drawn interest since the concept of constitutional varus was introduced. Proximal tibia vara is a condition where the knee varus tilt the tibia condyle medially and shift the tibial articular surface medially. This condition affects medial proximal tibial angle measurements and the placement of the tibial implant in knee replacement surgery. Thus, it challenged the neutral knee arthroplasty alignment target because some people may present a proximal tibia vara. This study assesses the prevalence of the proximal tibia vara and the correlation to knee osteoarthritis grade.

METHODS

This retrospective study was carried out from January 2021 to June 2021. Eighty-five limbs were included with the following inclusion criteria: knee osteoarthritis patients who received a long view lower extremity radiograph. The exclusions criteria were (1) patients who had undergone arthroplasty and lower extremity surgery before and (2) valgus knee deformity. The outcomes in this study were HKAA, MAD, TAD, MPTA, PTRP, LDFA, and PTS. Intraclass correlation (ICC) using two-way mixed was used to assess the reproducibility of the radiographic parameters. Multiple logistic regression was used to evaluate the correlation between knee osteoarthritis grade and radiographs parameters (MAD and TAD).

RESULT

A total 85 limbs from 52 patients were assessed in this study. Proximal tibia vara was found in 18 knees (21%.). The logistic regression was performed to assess the correlation between the severity of the knee osteoarthritis and radiographic parameters (MAD, TAD, LDFA, and PTS) with an overall p-value < 0.001 and pseudo-R² = 0.29.

CONCLUSION

A significant portion of patients with knee osteoarthritis have proximal tibia vara, and it is a pre-existing condition. Since the pre-existing proximal tibia vara affects preoperative measurements, a long-standing lower extremity x-ray is recommended to be obtained as part of knee replacement preparation.

Serial Improvement of Medial Meniscus Extrusion Following Medial Open-Wedge High Tibial Osteotomy Does Not Correlate With Clinical Outcomes and Arthroscopic Articular Cartilage Improvement

PURPOSE

To assess serial change up to 2 years in medial meniscus extrusion (MME) following medial open-wedge high tibial osteotomy (MOWHTO) and to determine whether postoperative changes in MME correlated with clinical outcomes and arthroscopic articular cartilage status.

METHODS

This study included 26 patients from December 2016 to March 2018 who underwent MOWHTO for primary medial osteoarthritis with varus malalignment. Second-look arthroscopy with plate removal was performed at postoperative 2 years. MME was consecutively measured using coronal magnetic resonance imaging at preoperative and postoperative 3 months, 6 months, 1.5 years, and 2 years. We also assessed which preoperative parameters could reflect the postoperative changes in MME and evaluated whether postoperative clinical outcomes and arthroscopic articular cartilage improvement would be influenced by the MME changes.

RESULTS

Regarding the postoperative serial changes in MME values, significant improvement in MME was noted from postoperative 6 months (P = .003), and thereafter, mean MME was further improved with time until postoperative 2 years (P < .001). Regarding the correlation between preoperative parameters and MME changes, preoperative medial proximal tibial angle (MPTA) showed significant correlations in univariate and multivariate analysis (P = .004 and P = .004, respectively). Meanwhile, changes in MME were not correlated with postoperative clinical outcomes or arthroscopic articular cartilage improvement.

CONCLUSION

After MOWHTO, MME improved with time and was significantly correlated with preoperative MPTA. However, the changes in MME after MOWHTO did not reflect postoperative clinical and arthroscopic articular cartilage improvement.

LEVEL OF EVIDENCE

IV, case series.

Medialization of the mechanical axis of the tibia is related to lateralization of the tibial tuberosity in knee osteoarthritis

PURPOSE

To determine whether medialization of the proximal tibia due to a varus deformity is related to lateralization of the tibial tuberosity in varus knee osteoarthritis (OA).

METHODS

A total of 120 knees that underwent osteotomies around the knee for varus knee OA were enrolled. Mechanical medial proximal tibial angle (mMPTA) was measured on radiographs. The angle between the mechanical and anatomical axes of the tibia (angle MA) and the distance between the centre of the tibial plateau and the anatomical axis (distance MA) were measured in the coronal plane on computed tomography images. The tibial tuberosity-posterior cruciate ligament (TT-PCL) distance, the distance between the midpoint of the tibial tuberosity and the centre of the tibial plateau (TT-centre distance), and the angle between the line through the midpoint of the tibial tuberosity and the centre of the tibial plateau and the anteroposterior axis (TT-centre angle) were measured in the axial plane. The correlations of these parameters were evaluated.

RESULTS

mMPTA correlated negatively with angle MA (r = -0.37, P < 0.01) and distance MA (r = -0.55, P < 0.01). Angle MA and distance MA correlated with TT-PCL distance (r = 0.39, P < 0.01, r = 0.42, P < 0.01), TT-centre distance (r = 0.35, P < 0.01, r = 0.38, P < 0.01) and TT-centre angle (r = 0.36, P < 0.01, r = 0.36, P < 0.01).

CONCLUSIONS

Medialization of the proximal tibia due to a varus deformity may induce lateralization of the tibial tuberosity.

Dome-shaped high tibial osteotomy with semi-circular Ilizarov pin fixator: Mid- to long-term results of a novel technique

BACKGROUND

The aim of this study was to assess the clinical and radiological results of the dome-shaped high tibial osteotomy (HTO) which was fixed with a novel construct comprised of semi-circular Ilizarov frames and pins.

METHODS

The patients with at least five years of follow-up were evaluated. One-hundred and thirty-two knees of 114 patients were included in the final analysis. The clinical evaluation included range of motion and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Anatomical femorotibial angle (aFTA), anatomical medial proximal tibial angle (aMPTA), tibial slope and Insall-Salvati ratio were calculated on standard weight-bearing radiographs.

RESULTS

The average aFTA was improved from 1.6° varus to 8.7° valgus (P < 0.001). The average WOMAC score (P < 0.001) and flexion value (P = 0.014) were improved at the latest follow-up (WOMAC: 17.2, flexion: 142.5) compared with the preoperative period (WOMAC: 59.6, flexion: 129.2). The sagittal radiological parameters were not significantly affected. The five-year survival was 96.2%, and 10-year survival was 83.3%.

CONCLUSIONS

The semi-circular Ilizarov pin construct provided satisfactory outcomes both clinically and radiologically at mid- to long-term follow-up.