The mediation effects of malalignment on the relation of sex to the risk of incidence tibiofemoral osteoarthritis.

OBJECTIVE: To investigate to what extent the higher risk of tibiofemoral radiographic osteoarthritis (TFROA) in females vs. males can be explained by knee malalignment. DESIGN: Using data from Multicenter Osteoarthritis Study (MOST) and Osteoarthritis Initiative (OAI), we examined the relation of sex to the incident medial and lateral TFROA and performed mediation analyses to assess to what extent varus and valgus malalignments account for sex differences in the incident medial or lateral TFROA. RESULTS: Of the 3462 knees without medial and lateral TFROA in MOST, the 7-year risks of medial and lateral TFROA were 16.9% and 10.0% in females, and 15.8% and 4.2% in males, respectively. Females had 2.31-fold (95% confidence interval [95% CI]: 1.73 to 3.08) higher incident lateral TFROA than males, and the relative risk (RR) of the indirect effect of sex on lateral TFROA through valgus malalignment was 1.15 (95% CI: 1.09 to 1.20), accounting for 23% of its total effect on lateral TFROA. In OAI (n = 3095 knees), females had 1.54-fold (95% CI: 1.15 to 2.04) higher incident lateral TFROA than males, and RR of the indirect effect of sex on lateral TFROA through valgus malalignment was 1.10 (95% CI: 1.04 to 1.21), accounting for 26% of its total effect on lateral TFROA. No apparent sex difference in the incident medial TFROA was found in MOST (RR = 1.05, 95% CI: 0.89 to 1.25) or OAI (RR = 1.02, 95% CI: 0.84 to 1.19). CONCLUSION: Females had a higher risk of developing lateral TFROA than males; however, valgus malalignment only modestly explained such a difference.

Osteoporotic vertebral fractures localized in the lumbar area significantly impact sagittal alignment.

Lumbar fractures and/or multiple fractures at the lumbar or thoracolumbar regions are risk factors for sagittal malalignment in patients older than 70 years old. Although patients with OVF show a huge capacity to compensate after the fractures, lumbar and TL lumbar fractures require closer monitoring. PURPOSE: To assess the impact of osteoporotic vertebral fractures on the sagittal alignment of the elderly and identify risk factors for sagittal malalignment. METHODS: We performed a retrospective study on a cohort of 249 patients older than 70 years old and diagnosed with osteoporosis who suffered chronic vertebral fractures. Demographic and radiological data were collected. Full-spine lateral X-rays were obtained to analyze the sagittal plane. Patients were classified according to the number and location of the fractures. Pearson's correlation coefficient was used to assess the relationships between the type of fractures and sagittal alignment. RESULTS: A total of 673 chronic fractures were detected in 249 patients with a mean number of vertebral fractures per patient of 2.7 ± 1.9. Patients were divided into 9 subgroups according to the location and the number of fractures. Surprisingly, any of the aggregated parameters used to assess sagittal alignment exceeded the threshold defined for malalignment. In the second part of the analysis, 41 patients with sagittal malalignment were identified. In this subpopulation, an overrepresentation of patients with lumbar fractures (34% vs. 11%) and an under-representation of thoracic fractures (9% vs. 34%) were reported. We also observed that patients with 3 or more lumbar or thoracolumbar fractures had an increased risk of sagittal malalignment. CONCLUSIONS: Lumbar fractures and/or multiple fractures at the lumbar or thoracolumbar regions are risk factors for sagittal malalignment in patients older than 70 years old. Although patients show a remarkable capacity to compensate, fractures at the lumbar and thoracolumbar regions need closer monitoring.

The role of radiography in diagnosing, monitoring and prognosing juvenile idiopathic arthritis.

The current role of conventional radiography in the diagnosis, monitoring and prognosis of juvenile idiopathic arthritis (JIA) is reviewed, as its role has changed with the increasing use of ultrasound and magnetic resonance imaging, as well as with the introduction of biological drugs. Conventional radiography does not play an important role in the diagnosis of JIA, as this is based on history, clinical examination and laboratory findings. The main role of conventional radiography is in the detection and monitoring of growth disorders and chronic structural and morphological changes of the affected joints and bones, in addition to helping with the differential diagnosis of conditions that mimic JIA. Radiographic changes of the joints depend on the age of the child, the type and duration of arthritis and the specific joints affected. There are no standard protocols for arthritis monitoring and most indications for imaging are based on individual case-by-case decisions. The development of degenerative joint changes is considered a poor predictive factor, but there are no clear studies that more precisely define the predictive value of radiographic changes. Conventional radiography remains an important imaging modality in narrowing the differential diagnosis and in evaluating growth disorders and the developing destructive joint changes.

Total hip arthroplasty after failed transtrochanteric rotational osteotomy for osteonecrosis of the femoral head: analysis of three-dimensional morphological features.

BACKGROUND: In total hip arthroplasty (THA) after failed transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head (ONFH), deformity of the proximal femur has been reported to affect stem placement. The aims of this study were to evaluate the morphological changes in the proximal femur, muscle atrophy, and soft tissue thickening in THA after TRO and the clinical outcomes. METHODS: The TRO group included 17 patients (18 hips) who underwent THA after failed TRO. The control group included 21 patients (28 hips) who underwent primary THA for ONFH. To evaluate the deformity of the proximal femur before THA, we measured the anteroposterior and mediolateral diameters of the femur on computed tomographic slices 5 mm proximal to the lesser trochanter. To evaluate muscle atrophy and soft tissue thickening, we measured the thicknesses of the psoas major, iliac, and gluteus medius muscles and the anterior capsule of the hip joint. RESULTS: The ratio of the anteroposterior to mediolateral diameters of the proximal femur was significantly greater in the TRO group (p < 0.01). The thicknesses of the muscles did not differ between the two groups, whereas the anterior capsule was significantly thicker in the TRO group (p < 0.05). Varus or valgus stem alignment (> 3°) was frequent in the TRO group (p < 0.01). CONCLUSIONS: The round shape of the proximal femur was deformed after TRO compared with primary THA for ONFH, which may have caused malposition of the stem. In addition, we should pay attention to anterior protrusion of the proximal femur and thickening of the anterior capsule.

Surgical treatment for recurrent patellar dislocation with severe torsional deformities: Double-level derotational osteotomy may not have a clear advantage over single-level derotational osteotomy in improving clinical and radiological outcomes.

PURPOSE: The purpose of this study was to investigate whether double-level (femur + tibia) derotational osteotomy is superior to single-level femoral derotational osteotomy for recurrent patellar dislocation with severe femoral and tibial rotational deformities (femoral anteversion >30° and external tibial torsion >30°). METHODS: Between January 2015 and June 2020, a total of 115 knees with recurrent patellar dislocation treated with combined medial patellofemoral ligament reconstruction (MPFL-R) and derotational osteotomies were evaluated after a minimum follow-up of 2 years. Among these cases, 15 knees that underwent double-level derotational osteotomy were included in the double-level group, which was propensity-matched in a 1:2 ratio to a single-level group of patients who underwent single-level femoral derotational osteotomy (30 knees). The clinical and radiological outcomes were evaluated and compared between the groups. Furthermore, the foot progression angle was measured preoperatively and 2 years after surgery. RESULTS: The patient-specific variables did not differ significantly between the double- and the single-level groups after propensity score matching. The postoperative mean foot progression angle was significantly lower in the double-level group than in the single-level group (9° ± 8° vs. 15° ± 11°; p = 0.014); however, there were no statistically significant differences between the groups in terms of any other clinical and radiological assessments. CONCLUSION: For patients with severe femoral and tibial torsional deformities (femoral anteversion >30° and external tibial torsion >30°), the double-level derotational osteotomy is superior to single-level osteotomy in maintaining normal foot progression angle, but it does not show an advantage in terms of patient-reported outcomes, radiological results and redislocation rate at minimum 2 years of follow-up. Furthermore, concomitant excessive external tibial torsion (>30°) did not have an adverse effect on clinical outcomes in patients who underwent derotational distal femoral osteotomy with MPFL-R due to excessive femoral anteversion. LEVEL OF EVIDENCE: Level III.

Valgus malalignment causes increased forces on a medial collateral ligament reconstruction under dynamic valgus loading: A biomechanical study.

PURPOSE: To investigate the forces on a medial collateral ligament (MCL) reconstruction (MCLR) relative to the valgus alignment of the knee. METHODS: Eight fresh-frozen human cadaveric knees were subjected to dynamic valgus loading at 400 N using a custom-made kinematics rig. After resection of the superficial medial collateral ligament, a single-bundle MCLR with a hamstring tendon autograft was performed. A medial opening wedge distal femoral osteotomy was performed and fixed with an external fixator to gradually adjust the alignment in 5° increments from 0° to 10° valgus. For each degree of valgus deformity, the resulting forces acting on the MCLR were measured through a force sensor and captured in 15° increments from 0° to 60° of knee flexion. RESULTS: Irrespective of the degree of knee flexion, increasing valgus malalignment resulted in significantly increased forces acting on the MCLR compared to neutral alignment (p < 0.05). Dynamic loading at 5° valgus resulted in increased forces on the MCLR at all flexion angles ranging between 16.2 N and 18.5 N (p < 0.05 from 0° to 30°; p < 0.01 from 45° to 60°). A 10° valgus malalignment further increased the forces on the MCLR at all flexion angles ranging between 29.4 N and 40.0 N (p < 0.01 from 0° to 45°, p < 0.05 at 60°). CONCLUSION: Valgus malalignment of the knee caused increased forces acting on the reconstructed MCL. In cases of chronic medial instabilities accompanied by a valgus deformity ≥ 5°, a realigning osteotomy should be considered concomitantly to the MCLR to protect the graft and potentially reduce graft failures. LEVEL OF EVIDENCE: Level III.

Deformity in valgus knee malalignment is not only in the femur but also in tibia or both, based on demographic and morphological analysis before and after knee osteotomies.

PURPOSE: This study aims to identify the demographic and morphological features of valgus knee deformity with unilateral osteoarthritic knee in the coronal plane. A secondary aim was to identify the distinct phenotypes of valgus knees in Hirschmann's phenotype and the coronal plane alignment of the knee (CPAK) classifications before and after a knee osteotomy (KO). METHODS: A total of 107 patients (57 female and 50 male) with a mean age of 42.4 ± 17.2 years, who underwent varisation osteotomy for symptomatic unilateral knee osteoarthritis (OA) and constitutional valgus deformity, were enrolled in the study, and the mean follow-up period was 29.1 ± 7.3 months. The included cases comprised 60 cases of distal femoral osteotomy, 10 cases of double-level osteotomy and 33 cases of high tibial osteotomy. All patients underwent preoperative and postoperative clinical, functional and radiological evaluations, analysed by analysis of variance tests. RESULTS: An analysis of the location of the valgus deformities demonstrated that 56 cases (52.3%) were femoral based, 18 cases (16.8%) were both femoral and tibial based and 33 cases (30.9%) were tibial based. Twelve preosteotomy cases (11.2%) and 38 postosteotomy cases (35.5%) matched the most common eight Hirschmann's phenotypes, phenotyping the coronal lower limb alignment based on the native alignment in young patients without OA. Four (3.7%) preosteotomy cases and 89 postosteotomy cases (83.1%) matched the most common three CPAK phenotypes (Ⅰ, Ⅱ, Ⅴ) based on constitutional alignment and joint line obliquity in healthy and osteoarthritic knees. CONCLUSION: In valgus knee malalignment, the location of the deformity is not only solely femoral-based but also solely tibial-based or combined femoral and tibial-based. An individualised osteotomy approach would be recommended to achieve careful preoperative planning that considers the location of the deformity and the resultant joint line. Hirschmann's and CPAK classification would not be relevant when KO is considered. LEVEL OF EVIDENCE: Level Ⅳ, retrospective case-control study.

Fixed-Bearing Unicompartmental Knee Arthroplasty in Tibia Vara Knees Results in Joint Surface Malalignment and Varus Joint Line Obliquity, but Does Not Affect Functional Outcomes at Greater Than 5 Years Follow-Up.

BACKGROUND: This study aimed to investigate the clinical outcomes of fixed-bearing medial unicompartmental knee arthroplasty (UKA) for tibia vara knees and the associated changes in joint space malalignment (JSM) and joint line obliquity (JLO). METHODS: We retrospectively analyzed a consecutive group of 100 patients who underwent fixed-bearing medial UKA with a preoperative medial proximal tibia angle (MPTA) ≥86° (n = 50) and MPTA <86° (n = 50) and who had a minimum 5-year follow-up. Radiological parameters, including the hip-knee-ankle angle, MPTA, and the postoperative JSM and JLO, were measured. Functional evaluation was performed using the range of motion, visual analog scale, Knee Society Knee Score, Knee Society Function Score, and Western Ontario and McMaster Universities Osteoarthritis Index score. RESULTS: The MPTA <86° group showed significantly higher postoperative JLO (91.8 versus 90.4°, respectively; P = .002) and JSM (6.1 versus 4.2°, respectively; P = .026) compared to the MPTA ≥86° group. Functional outcomes, including range of motion, visual analog scale, Knee Society Knee Score, Knee Society Function Score, and Western Ontario and McMaster Universities Osteoarthritis Index scores, were not significantly different between the 2 groups. CONCLUSIONS: Fixed-bearing medial UKA is a safe and effective surgical option for patients who have tibia vara knees, as an increase in JLO and JSM postoperatively does not have a clinically relevant impact, even after a minimum 5-year follow-up.

Blocking screw (pin) technique to achieve an acceptable reduction in intramedullary of subtrochanteric femoral fractures: indications, techniques, and clinical outcomes.

INTRODUCTION: Subtrochanteric femur fractures treated with intramedullary nails present biomechanical benefits, early weight-bearing, and reduced soft tissue damage, promoting bone union. However, improper reduction due to muscular forces and fragmented proximal bone increases nonunion risk. This study evaluates the efficacy of the blocking screw technique in preventing malalignment during intramedullary nailing. MATERIAL AND METHODS: In cases of subtrochanteric femoral fractures where malalignment, such as varus and anterior angulation, was anticipated during intramedullary nailing, proper reduction was ensured using blocking screw technique on the proximal bone fragment from the coronal or sagittal plane. A retrospective analysis was conducted on 25 patients (14 males, 11 females; average age 55.12 years) who were followed up for more than 1 year. The postoperative neck-shaft angle, anterior angulation angle, and limb length discrepancy were compared radiologically with those on the healthy side, and the presence and duration of bone union were measured. The Harris hip score was used for functional evaluation, and complications, including infection, were analyzed. RESULTS: At the final follow-up, primary bone union was achieved in 21/25 patients (84%), with an average bone union time of 21.81 weeks (range, 14-42 weeks). Of the four nonunions, bone union was achieved in three cases through bone grafting and supplemental plating and in the other case through intramedullary exchange, supplemental plating, and bone grafting. The femoral neck-shaft angle and anterior angulation showed no statistically significant differences compared with the healthy side, with averages of - 1.15° and - 1.4°, respectively. The limb length discrepancy was an average of - 2.4 mm. Regarding functional outcomes, the Harris hip score averaged 89.52 points (range 82-94 points). CONCLUSIONS: In subtrochanteric femoral fractures, the blocking screw technique effectively prevents malalignment during intramedullary nailing, ensuring not only appropriate reduction but also high bone union rates.

Effect of ascending and descending medial open wedge high tibial osteotomy on patella height and functional outcomes-a retrospective study.

BACKGROUND: High tibial osteotomy (HTO) is a popular joint-preserving option for medial compartmental osteoarthritis. However, this is associated with alterations in the patellar height (PH) and tibial slope (TS). This study aims to compare the effect of ascending (AMHTO) and descending medial opening wedge HTO (DMHTO) on patella height, posterior tibial slope and functional outcomes. MATERIAL AND METHODS: A retrospective study was conducted between February 2018 and July 2021. Patients with medial compartment osteoarthritis, varus alignment, and complete pre- and postoperative lateral and full-length anteroposterior radiographs were included. Pre- and postoperative radiological measurements include the Caton-Deschamps index (CDI), the mechanical axis deviation (MAD), and the posterior tibial slope. The functional outcomes were measured using the Oxford Knee Score (OKS), Lysholm Knee Score (LKS), and Tegner Activity Scale (TAS). The osteotomy union was checked with serial X-rays every 6 weeks till a satisfactory union was achieved. RESULTS: Fifty-eight patients were included in the study. Thirty-four (58%) patients received AMHTO, and 24 (42%) received DMHTO. There was no baseline difference in the demographic variables or functional scores between the two groups. The preoperative mean MAD of - 9.65° ± 3.67° was corrected significantly to + 0.08 ± 2.80° (varus -, valgus + , P = 0.034). A significant difference in preoperative and postoperative CDI of 0.93 ± 0.45 and 0.83 ± 0.27, respectively, was noted (P = 0.023). In the AMHTO group, a statistically significant decrease in PH from preoperative 1.03 ± 0.77 to 0.84 ± 0.12 was noted (P = 0.003). There was a significant improvement in functional outcomes between baseline and 9-month follow-up in both groups. There was no significant difference between the functional outcomes of the two groups at 9-month follow-up. CONCLUSION: The study confirmed our hypothesis that descending HTO caused less alteration in the patella height compared to ascending HTO. There is no significant difference in the functional outcomes between the groups. However, in patients with PFOA, and when attempting higher degree of correction through AMHTO, the possibility of worsening of symptoms due to change in PH must be considered.

Association between modic changes, disc degeneration, and pelvic incidence-lumbar lordosis mismatch in a large population based cohort: the Wakayama spine study.

PURPOSE: Sagittal plane alignment is crucial for treating spinal malalignment and low back pain. Pelvic incidence-lumbar lordosis (PI-LL) mismatch is commonly used to evaluate clinical outcomes in patients with sagittal malalignment. The association between PI-LL mismatch and changes surrounding the intervertebral disc is very important to understand the compensatory mechanisms involved. This study aimed to examine the association between PI-LL mismatch and magnetic resonance imaging (MRI) changes surrounding the intervertebral disc in a large population-based cohort. METHODS: We evaluated participants from the second Wakayama Spine Study, recruiting the general population aged 20 years or older, irrespective of sex, who were registered residents in one region in 2014. In total, 857 individuals underwent an MRI of the whole spine; however, 43 MRI results were not included due to incomplete or inadequate quality images. PI-LL mismatch was defined as > 11°. We compared the MRI changes, such as Modic change (MC), disc degeneration (DD), and high-intensity zones (HIZ), between PI-LL mismatch and non-PI-LL mismatch groups. Multivariate logistic regression analysis was conducted to determine the association between the MRI changes and PI-LL mismatch with adjustment for age, sex, and body mass index in the lumbar region and at each level. RESULTS: A total of 795 participants (243 men, 552 women, mean age 63.5 ± 13.1 years old) were evaluated; 181 were included in the PI-LL mismatch group. MC and DD in the lumbar region were significantly higher in the PI-LL mismatch group. MC in the lumbar region was significantly associated with PI-LL mismatch (odds ratio (OR); 1.81, 95% confidence interval (CI) 1.2-2.7). MC at each level was significantly associated with PI-LL mismatch (OR; 1.7-1.9, 95%CI 1.1-3.2), and DD at L1/2, L3/4, and L4/5 was associated with PI-LL mismatch (OR; 2.0- 2.4. 95%CI 1.2-3.9). CONCLUSION: MC and DD were significantly associated with PI-LL mismatch. Therefore, profiling MC may be helpful in improving the targeted treatment of LBP associated with the adult spinal deformity.

Adherence to the Obeid coronal malalignment classification and a residual malalignment below 20 mm can improve surgical outcomes in adult spine deformity surgery.

PURPOSE: Coronal balance is a major factor impacting the surgical outcomes in adult spinal deformity (ASD). The Obeid coronal malalignment (O-CM) classification has been proposed to improve the coronal alignment in ASD surgery. Aim of this study was to investigate whether a postoperative CM < 20 mm and adherence to the O-CM classification could improve surgical outcomes and decrease the rate of mechanical failure in a cohort of ASD patients. METHODS: Multicenter retrospective analysis of prospectively collected data on all ASD patients who underwent surgical management and had a preoperative CM > 20 mm and a 2-year follow-up. Patients were divided in two groups according to whether or not surgery had been performed in adherence to the guidelines of the O-CM classification and according to whether or not the residual CM was < 20 mm. The outcomes of interest were radiographic data, rate of mechanical complications and Patient-Reported Outcome Measures. RESULTS: At 2 years, adherence to the O-CM classification led to a lower rate of mechanical complications (40 vs. 60%). A coronal correction of the CM < 20 mm allowed for a significant improvement in SRS-22 and SF-36 scores and was associated with a 3.5 times greater odd of achieving the minimal clinical important difference for the SRS-22. CONCLUSION: Adherence to the O-CM classification could reduce the risk of mechanic complications 2 years after ASD surgery. Patients with a residual CM < 20 mm showed better functional outcomes and a 3.5 times greater odd of achieving the MCID for the SRS-22 score.

The Obeid-coronal malalignment classification is reliable and helps guiding decision-making and surgical management of adult spinal deformities: letter to the editor of BMC Musculoskeletal Disorders.

A recently published article by Zhang et al. in BMC Musculoskeletal Disorders reported that the classification of coronal deformity based on preoperative global coronal malalignment for adult spinal deformity is questionable. The aim of the paper was to specifically discredit the Obeid-Coronal Malalignment (O-CM) classification. In this correspondence, we thought it judicious to clarify misunderstood concepts by the authors. We highlight several limitations of their study, and explain the deep interest of the classification from our perspective in order to avoid misleading the readers. Overarching, we aim to help the colleagues through a constructive rather than destructive approach to better understand the foundations of a coronal malalignment classification.

The gap height in open wedge high tibial osteotomy is not affected by the starting point of the osteotomy.

INTRODUCTION: In open-wedge high-tibial-osteotomy (OWHTO), most surgeons use a preoperative planning software and realise that they should match the intraoperative alignment correction with the preoperative plan. We aimed to determine whether there is a difference in osteotomy gap height when starting the OWHTO either 3 or 4 cm distal to the joint line. This should help to clarify whether the osteotomy starting point must exactly match the preoperative planning. METHODS: 25 patients with constitutional varus alignment were planned for OWHTO. Long-leg-standing-radiographs and mediCAD-software were used. Osteotomy was planned to a neutral Hip-Knee-Ankle angle (HKA) of 0°. The osteotomy-starting-point was either 3 or 4 cm distal to the medial joint line. The following angles were compared: mechanical medial proximal tibial angle (mMPTA), mechanical lateral distal femoral angle (mLDFA), joint line conversion angle (JCA), mechanical Tibio-Femoral angle (mTFA) or Hip Knee Ankle (HKA) angle. RESULTS: 25 Patients (18 males, 7 females) had a mean age of 62 ± 16.6 years and showed a varus-aligned leg-axis. The HKA was - 5.96 ± 3.02° with a mMPTA of 82.22 ± 1.14°. After osteotomy-planning to a HKA of 0°, the mMPTA was 88.94 ± 3.01°. With a mean wedge height of 8.08 mm when locating the osteotomy 3 cm and a mean wedge height of 8.05 mm when locating the osteotomy 4 cm distal to the joint-line, there was no statistically significant difference (p = 0.7). CONCLUSION: When performing an OWHTO aiming towards the tip of the fibula, the osteotomy starting point does not need to exactly match the planned starting-location of the osteotomy. A starting-point 1 cm more distal or proximal than previously determined through the digital planning does not alter the size of the osteotomy gap needed to produce the desired amount of correction.

In closed wedge distal femur osteotomies for correction of valgus malalignment overcorrection of mLDFA should be avoided.

PURPOSE: The purpose of the study was to investigate the influence of the mLDFA (mechanical lateral distal femur angle) as a parameter in varus realignment osteotomies for valgus deformities of the knee. We hypothesized that joint line obliquity with mLDFA > 90° after distal femur osteotomy (DFO) is associated with inferior clinical outcome. METHODS: In a retrospective study, a total of 52 patients with isolated femoral valgus deformities were included in the study. The mean postoperative follow-up was 70.5 (SD 33.3) months (standard deviation SD±33.3). In all patients, a distal femur osteotomy was performed. A clinical examination and survey of questionnaires was conducted with the HSS (Hospital for Special Surgery), LG (Lysholm-Gilquist), and KOOS (Knee Injury and Osteoarthritis Outcome Score) scores. Several radiological parameters were assessed on long-standing x-rays: mechanical tibio-femoral angle (mTFA), mLDFA, mechanical medial proximal tibia angle (mMPTA), joint-line convergence angle (JLCA). The t test was used for normally distributed data. The Mann-Whitney U test was performed in non-normally distributed data. RESULTS: The mLDFA was 84.9° (SD±2.3) preop and changed to 91.9° (SD±3, 22.9) postop. The mTFA (mechanical tibio-femoral angle) was 5.2° (SD±2.9°) preop and - 1.8° (SD±2.9) postop demonstrating a difference of 6.7°. For analysis, the data was divided into two groups based on postop mLDFA. Group 1: mLDFA ≤ 90°; Group 2: > 90°. Postoperatively, a mean mLDFA of 88.6° (SD±1.4°) was measured in group 1 and 93.9° (SD±2.1) in group 2. The change in mLDFA was 4.7° (SD±1.6) in group 1 and 8.4° (SD±2.8) in group 2. Preoperatively, the mTFA was 4.8° (SD±1.9) in group 1 and 5.5° (SD±3.3) in group 2. Postoperatively, the mTFA decreased in group 1 by 4.8° (SD±2.3) to - 0.1° (SD±2.1). In group 2, the mTFA decreased by 8.2° (SD±3.8) to - 2.8° (SD±2.9). Regarding the HSS, group 1 showed a 10.4 points better score than group 2 (p<0.01). Also, regarding the Lysholm, a significant difference of 16.9 points was found (p<0.01). CONCLUSION: Correction of valgus knees using closed wedge DFO leads to good clinical results. A postoperative mLDFA of 85-90° results in superior clinical outcome compared to mLDFA > 90°. Joint-line obliquity should be avoided using double level osteotomy, if needed. LEVEL OF EVIDENCE: III.

MRI-based torsion measurement of the lower limb is a reliable and valid alternative for CT measurement: a prospective study.

PURPOSE: The aim of this study was to compare MRI-based torsion measurements of the lower limb to a well-established CT-based assessment in a prospective inter- and intraindividual approach. METHODS: A total of 26 patients (age 28.8 years ± 11.0) were enrolled beginning in January 2021 until August 2022. Inclusion criteria were the clinical indication for torsion measurement of the lower limb. CT and MRI imaging were performed with a standard operating procedure, to ensure that all patients were examined in a standardized position. The examinations were planned on a coronal scout view based on prominent anatomical landmarks. Femoral and tibial torsion were measured individually. Torsion measurements were analysed twice: immediately after examination and after 3 weeks. Subsequently, intra-rater and parallel test reliability was calculated accordingly. RESULTS: High significant results for CT and MRI measurements for both tibia (MRI: r = 0.961; p ≤ 0.001; CT: r = 0.963; p ≤ 0.001) and femur (MRI: r = 0.980; p ≤ 0.001; CT: r = 0.979; p ≤ 0.001) were obtained by calculated intra-rater reliability, showing that measurements were highly consistent for MRI and CT, respectively. Parallel test reliability for time point 1 as well as time point 2 was also highly significant and ranged from r = 0.947 to r = 0.972 (all with p ≤ 0.001, respectively) for both tibia and femur, showing a high concordance between the two measurements. CONCLUSION: Measurement of tibial as well as femoral torsion was comparable for CT and MRI measurement. Therefore, this study supports MRI measurement as an equivalent alternative for CT measurement concerning torsional malalignment to reduce exposure to radiation. LEVEL OF EVIDENCE: Level II.

Quadriceps tendon malalignment is an independent anatomical deformity which is the primary abnormality associated with lateral facet patellofemoral joint osteoarthritis.

PURPOSE: The purposes of this study are to, firstly, develop techniques to accurately identify extensor mechanism malalignment by measuring the alignment of the quadriceps tendon (QTA) with computerized tomography (CT) scans. Secondly, to investigate correlations between QTA and lower limb bony anatomical variations within a representative normal population. Lastly, to evaluate the clinical significance of QTA by establishing its potential connection with lateral facet patellofemoral joint osteoarthritis (LFPFJOA). METHOD: CT scans were orientated to a mechanical axis reference frame and three techniques developed to measure the alignment of the quadriceps tendon. Multiple measurement of bony alignment from the hip to the ankle were performed on each scan. A series of 110 cadaveric CT scans were measured to determine normal values, reproducibility, and correlations with bony anatomy. Secondly, a comparison between 2 groups of 25 patients, 1 group with LFPFJOA and 1 group with isolated medial OA and no LFPFJOA. RESULTS: From the cadaveric study, it was determined that the alignment of the quadriceps tendon is on average 4.3° (SD 3.9) varus and the apex of the tendon is 9.1 mm (SD 7.7 mm) lateral to the trochlear groove and externally rotated 1.9° (SD 12.4°) from the centre of the femoral shaft. There was no association between the quadriceps tendon alignment and any other bony measurements including tibial tubercle trochlear groove distance (TTTG), coronal alignment, trochlear groove alignment and femoral neck anteversion. A lateralized QTA was significantly associated with LFPFJOA. QTA in the LFPFJOA group was 9.6° varus (SD 2.8°), 21.3 mm (SD 6.6) lateralised and 17.3° ER (SD 11°) compared to 5.5° (SD 2.3°), 10.7 mm (SD 4.9) and 3.3° (SD 7.2°), respectively, in the control group (p < 0.001). A significant association with LFPFJOA was also found for TTTG (17.2 mm (SD 5.7) vs 12.1 mm (SD 4.3), p < 0.01). Logistic regression analysis confirmed the QTA as having the stronger association with LFPFJOA than TTTG (AUC 0.87 to 0.92 for QTA vs 0.79 for TTTG). CONCLUSION: These studies have confirmed the ability to accurately determine QTA on CT scans. The normal values indicate that the QTA is highly variable and unrelated to bony anatomy. The comparative study has determined that QTA is clinically relevant and a lateralised QTA is the dominant predictor of severe LFPFJOA. This deformity should be considered when assessing patella maltracking associated with patella osteoarthritis, patella instability and arthroplasty. LEVEL OF EVIDENCE: III (retrospective cohort study).

Assessment of return to sport and functional outcomes following distal femoral, double level and high tibial osteotomies for active patients with symptomatic varus malalignment.

PURPOSE: This study indicated the outcomes of three surgical techniques for the treatment of symptomatic unicompartmental knee osteoarthritis (UKOA) with varus malalignment in younger, active patients: distal femoral osteotomy (DFO), double-level osteotomy (DLO) and high tibial osteotomy (HTO). The outcomes measured included the return to sport, sport activity and functional scores. METHODS: A total of 103 patients (19 DFO, 43 DLO, 41 HTO) were enrolled in the study and were divided into three groups based on their oriented deformity, each undergoing one of the three surgical techniques. All patients underwent pre- and post-operative evaluations including X-rays, physical exams and functional assessments. RESULTS: All three surgical techniques were effective in treating UKOA with constitutional malalignment. The average time to return to sport was similar among the three groups (DFO: 6.4 ± 0.3 [5.8-7] months, DLO: 4.9 ± 0.2 [4.5-5.3] months, HTO: 5.6 ± 0.2 [5.2-6] months). The sport activity and functional scores improved significantly for all three groups, with no significant differences observed among the groups. CONCLUSION: Various knee osteotomy procedures, DFO, DLO, and HTO, result in high RTS rates and quick RTS times with satisfactory functional scores. Despite pre- to post-operative improvements in sport activities following DFO and DLO, pre-symptom levels were not reached following all evaluated procedures. LEVEL OF EVIDENCE: Retrospective case-control study, Level III.

Automating Angle Measurements on Foot Radiographs in Young Children: Feasibility and Performance of a Convolutional Neural Network Model.

Measurement of angles on foot radiographs is an important step in the evaluation of malalignment. The objective is to develop a CNN model to measure angles on radiographs, using radiologists' measurements as the reference standard. This IRB-approved retrospective study included 450 radiographs from 216 patients (< 3 years of age). Angles were automatically measured by means of image segmentation followed by angle calculation, according to Simon's approach for measuring pediatric foot angles. A multiclass U-Net model with a ResNet-34 backbone was used for segmentation. Two pediatric radiologists independently measured anteroposterior and lateral talocalcaneal and talo-1st metatarsal angles using the test dataset and recorded the time used for each study. Intraclass correlation coefficients (ICC) were used to compare angle and paired Wilcoxon signed-rank test to compare time between radiologists and the CNN model. There was high spatial overlap between manual and CNN-based automatic segmentations with dice coefficients ranging between 0.81 (lateral 1st metatarsal) and 0.94 (lateral calcaneus). Agreement was higher for angles on the lateral view when compared to the AP view, between radiologists (ICC: 0.93-0.95, 0.85-0.92, respectively) and between radiologists' mean and CNN calculated (ICC: 0.71-0.73, 0.41-0.52, respectively). Automated angle calculation was significantly faster when compared to radiologists' manual measurements (3 ± 2 vs 114 ± 24 s, respectively; P < 0.001). A CNN model can selectively segment immature ossification centers and automatically calculate angles with a high spatial overlap and moderate to substantial agreement when compared to manual methods, and 39 times faster.

A smaller femoral stem is needed for asian females.

BACKGROUND: Current femoral implants are manufactured based on Western anatomical structures and may be too large for smaller physiques, such as those of Asian females. This study reviewed the femoral stem size distribution used in a high-volume total hip arthroplasty (THA) practice and evaluated malalignment in patients receiving a size one implant. MATERIALS AND METHODS: A consecutive cohort of female patients self-reported as Asian (257 patients, 331 hips) or Caucasian (158 patients and 190 hips) were retrospectively evaluated. A single femoral stem type was used in all cases, performed by a single surgeon. Global hip offset (GHO) and leg length difference (LLD) were measured before and 6 weeks following THA. Differences between races were evaluated through Mann-Whitney U tests and chi-squared tests for continuous and categorical variables, respectively. RESULTS: The proportion of size one implants was higher amongst Asian patients (20.5%) than Caucasian patients (2.6%) (p < 0.001). A LLD greater than 6 mm was noted in 24.6% of size one patients and 11.4% of all other sizes (p = 0.010). Varus malalignment occurred in 47.9% of size one patients and 22.1% of all other sizes (p < 0.001). No fractures occurred in size one patients, and nine fractures (one intraoperative and eight post-operative) occurred in all other sizes (p = 0.258). CONCLUSION: The high proportion of size one stems required in Asian females and the higher incidence of LLD > 6 mm and varus malalignment suggest a distinct need for smaller femoral implants, especially for Asian females.