Preoperative Lateral Radiographs Research Articles

Association of Radiographic Soft Tissue Thickness with Revision Total Ankle Arthroplasty Following Primary Total Ankle Arthroplasty: A Minimum of 5-year Follow-up

Category: Ankle; Ankle Arthritis Introduction/Purpose: The incidence of primary total ankle arthroplasty (TAA) is rising, with a corresponding increase in revision surgeries. Despite this, research on risk factors for revision TAA following primary TAA remains limited. Radiographic soft-tissue thickness has been explored as a potential predictor for outcomes in hip, knee, and shoulder arthroplasty, but its role in TAA has not been assessed. This study aimed to assess the predictive value of radiographic soft tissue thickness for identifying patients at risk of requiring revision surgery following primary TAA. Methods: A retrospective study was conducted on 323 patients who underwent primary TAA between 2003 and 2019. Radiographic measurements of soft tissue thickness were obtained from preoperative lateral weightbearing radiographs. Clinical variables including age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, diabetes, smoking status, primary diagnosis, and implant type were recorded. Logistic regression analysis was used to assess the predictive value of soft tissue thickness and BMI for revision TAA. Results: The rate of revision surgery was 4.3% (14 out of 323 patients). Patients requiring revision had significantly greater tibial-tissue (3.54 vs. 2.48 cm; p=0.02) and talus-tissue (2.79 vs. 2.42 cm; p=0.02) thickness compared to those who did not require revision. Both the Tibial-Tissue thickness (Odds Ratio: 1.16 [1.12-1.20]; p < 0.01) and the Talus-Tissue thickness (Odds Ratio: 1.10 [1.05-1.15]; p < 0.01) measurements were significant predictors of revision TAA in multivariable logistic regression models. In contrast, BMI was not a significant predictor of revision TAA. The two metrics demonstrated excellent interrater reliability. Conclusion: Greater soft tissue thickness, as measured radiographically, was a better predictor of revision TAA compared to BMI. These findings suggest that radiographic soft tissue thickness may be a valuable tool for assessing the risk of the need for revision TAA following primary TAA. Further research is needed to validate these findings and explore the potential impact on clinical practice. Figure 1. Radiographical Assessment of Tissue Thickness The figure illustrates the method for obtaining the radiographic measurements on weightbearing lateral radiographs. (A) A line was drawn from the posterior distal tibia to the anterior distal tibia (Red Line), and the distance of the parallel segment extending from the anterior cortex of the tibia to the end of the soft tissue shadow was measured to determine the Tibial-Tissue thickness. A line was drawn from the lateral process of the talus to the head/neck junction of the talus (Yellow Line), and the distance of the parallel segment, extending from the head/neck junction of the talus to the end of the soft tissue shadow, was measured to determine the Talus-Tissue thickness.

Radiological measurement of posterior tibial subluxation as a preoperative factor in choosing the type of implant in primary total knee arthroplasty.

Total knee arthroplasty (TKA) is the most effective treatment of late osteoarthritis (OA) and is considered among the most successful surgical procedures in general. However, about 20% of patients remain dissatisfied. An important aspect of TKA is the proper choice of implant type - posterior stabilized (PS) or cruciate retaining (CR). Both have their indications for use based on intraoperative functional examination, but no objective radiological criteria have yet been developed. The aim of this study was to investigate the relationship between the posterior subluxation of the tibia on preoperative radiograms and implant type used. A series of 52 patients undergoing TKA were included in the study. All patients were over 50 years old, had clinically and radiologically confirmed primary OA of grade IV on the Kellgren-Lawrence scale and were undergoing a primary total knee replacement (TKR) with a PS or CR design. Preoperative lateral radiographs were analysed retrospectively. The tibial translation ratio was calculated as a percentage of subluxation in the length of the tibial plateau. There were no significant differences between implant types in regard to investigated parameters. However, there was a significant difference between the groups CR and PS in regard to age (68.5 [60.0-72.0] vs. 72.5 [68.0-75.0], p = 0.006). This study revealed that preoperative tibial translation does not significantly correlate with the choice of implant type and so probably not with posterior cruciate ligament (PCL) function and efficiency either. Additionally, this study showed that PCL insufficiency is related to the age of the patients, because of the more frequent choice of the PS implant type for the surgery in older patients than in the case of the CR implant type.

The Posterior Tibial Slope Is Not Associated With Graft Failure and Functional Outcomes After Anatomic Primary Isolated Anterior Cruciate Ligament Reconstruction

Background: Biomechanical studies have shown that an increased medial posterior tibial slope (MPTS) may affect anteroposterior knee laxity and tibial shear forces, ultimately increasing the risk for graft failure after anterior cruciate ligament (ACL) reconstruction. Previous clinical studies have, however, reported inconclusive results. Purpose: The purpose of this study was to evaluate the relationship between the MPTS and graft failure as well as functional outcomes after anatomic primary isolated ACL reconstruction using a hamstring tendon autograft. It was hypothesized that an increased MPTS would be associated with a higher ACL graft failure rate. Furthermore, a higher MPTS would negatively correlate with functional outcomes in patients without ACL graft failure. Study Design: Case-control study; Level of evidence, 3. Methods: Consecutive patients who underwent isolated primary ACL reconstruction with an anteromedial portal drilling technique between January 2011 and December 2019 were retrospectively reviewed. The MPTS was measured on preoperative lateral knee radiographs. At a minimum of 24 months postoperatively, the ACL graft failure rate and patient-reported outcome measures (PROM; International Knee Documentation Committee subjective knee form, Lysholm score, Tegner Activity Scale, visual analog scale for pain and subjective instability) were evaluated. Differences in the MPTS between patients with and without ACL graft failure as well as the frequency of graft failure between those with an MPTS <12° and those with an MPTS ≥12° were assessed for statistical significance. Binary logistic regression analysis was performed to stratify the risk of graft failure with the following variables: MPTS, age at surgery, and sex. Correlation analysis was performed to evaluate the relationship between the MPTS and PROM in patients without ACL graft failure. Results: In total, 326 patients were included (median follow-up, 71.0 months [IQR, 49.0-104.0 months]). There was no significant difference in the MPTS between patients with and without graft failure (10.6°± 3.2° vs 11.2°± 2.8°, respectively; P = .264). Additionally, there was no significant difference in the frequency of graft failure between patients with an MPTS <12° and those with an MPTS ≥12° (15.6% vs 16.5%, respectively; P = .835). Binary logistic regression showed that younger age at the time of surgery (odds ratio, 1.069 [95% CI, 1.031-1.109]) was associated with graft failure; sex and MPTS were not associated with graft failure. In patients without ACL graft failure, there was no significant correlation between the MPTS and PROM. Conclusion: In patients who underwent anatomic primary isolated ACL reconstruction, an increased MPTS was not associated with a higher rate of graft failure or inferior functional outcomes. Younger age was a significant nonmodifiable risk factor for ACL graft failure.

Radiological study of foramen arcuale: implications for screw insertion via posterior arch for fixation of C1 vertebrae in atlantoaxial instability using plain radiograph

Abstract Introduction: Foramen arcuale is an osseous structure forming a bridge from the superior articular process of the atlas that completely or partially encircles the vertebral artery. We retrospectively reviewed plain cervical radiographs as suggested by neurosurgeons, neurologists and orthopaedic surgeons for evaluation of cervical spine problems. When foramen arcuale is present, it creates a false impression of a broad posterior arch and can pose a risk during neurosurgery. The aim of this study is to investigate the prevalence of foramen arcuale in the Jalgaon &amp; Baramati population. Materials and Methods: 1255 lateral cervical spine radiographs were obtained from the radiology department, GMC, Jalgaon &amp; GMC Baramati. The patient of which 655 (59.04%) were males and 600(31.42%) were females. Cases were classified as an incomplete and complete bony ridge. Results: Overall prevalence of Foramen arcuale was 8.36%, with complete lesions in 3.50% and incomplete lesions in 4.86%. We noted an increasing percentage of patients with Foramen arcuale from the younger to the adolescent age group, with significantly greater prevalence in patients aged 15-30 years compared with the younger groups. Lesions were more common in males (59.04%) compared with females (31.42%), but no statistically significant difference between genders was detected for complete as well as incomplete foramen arcuale (p=0.95). Conclusion: The foramen arcuale is a relatively common osseous structural variant therefore; surgeons should consider the risk of the presence of an FA prior to procedures on the atlas in each patient. So we suggest the identification of this variant by preoperative lateral radiograph as a starting point for C1 lateral mass for screw fixation via the posterior arch for atlantoaxial instability. If foramen arcuale is suspected or confirmed on a radiograph, 3D CT scanning should be considered for variations in size and shape of foramen arcuale and the possibility of injury to the vertebral artery.

Artificial Intelligence to Preoperatively Predict Proximal Junction Kyphosis Following Adult Spinal Deformity Surgery: Soft Tissue Imaging May Be Necessary for Accurate Models.

Retrospective cohort. In a cohort of patients undergoing adult spinal deformity (ASD) surgery, we used artificial intelligence to compare three models of preoperatively predicting radiographic proximal junction kyphosis (PJK) using: (1) traditional demographics and radiographic measurements, (2) raw preoperative scoliosis radiographs, and (3) raw preoperative thoracic magnetic resonance imaging (MRI). Despite many proposed risk factors, PJK following ASD surgery remains difficult to predict. A single-institution, retrospective cohort study was undertaken for patients undergoing ASD surgery from 2009 to 2021. PJK was defined as a sagittal Cobb angle of upper-instrumented vertebra (UIV) and UIV+2>10° and a postoperative change in UIV/UIV+2>10°. For model 1, a support vector machine was used to predict PJK within 2 years postoperatively using clinical and traditional sagittal/coronal radiographic variables and intended levels of instrumentation. Next, for model 2, a convolutional neural network (CNN) was trained on raw preoperative lateral and posterior-anterior scoliosis radiographs. Finally, for model 3, a CNN was trained on raw preoperative thoracic T1 MRIs. A total of 191 patients underwent ASD surgery with at least 2-year follow-up and 89 (46.6%) developed radiographic PJK within 2 years. Model 1: Using clinical variables and traditional radiographic measurements, the model achieved a sensitivity: 57.2% and a specificity: 56.3%. Model 2: a CNN with raw scoliosis x-rays predicted PJK with a sensitivity: 68.2% and specificity: 58.3%. Model 3: a CNN with raw thoracic MRIs predicted PJK with average sensitivity: 73.1% and specificity: 79.5%. Finally, an attention map outlined the imaging features used by model 3 elucidated that soft tissue features predominated all true positive PJK predictions. The use of raw MRIs in an artificial intelligence model improved the accuracy of PJK prediction compared with raw scoliosis radiographs and traditional clinical/radiographic measurements. The improved predictive accuracy using MRI may indicate that PJK is best predicted by soft tissue degeneration and muscle atrophy.

Influence of Patellofemoral Anatomy on Outcomes of Isolated Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability.

Background:Patella alta and elevated tibial tubercle–trochlear groove (TT-TG) distance can predispose patients to lateral patellar dislocations and recurrent instability. Their influence on patient-reported outcomes (PROs) after medial patellofemoral ligament (MPFL) reconstruction is less clear.Hypothesis:We hypothesized that neither moderately increased TT-TG distance nor patella alta would negatively affect PROs after isolated MPFL reconstruction in patients with relatively normal patellar tracking (no large J-sign).Study Design:Cohort study; Level of evidence, 3.Methods:We identified patients who underwent isolated MPFL reconstruction at a single institution between 2008 and 2016. The decision to perform an isolated MPFL reconstruction was at the discretion of the operating surgeon but was not performed in the setting of a large J-sign. Patient characteristics and surgical details were collected, and patients completed the Norwich Patellar Instability Score, Knee injury and Osteoarthritis Outcome Score, and Marx activity score. Patellar height (Caton-Deschamps Index [CDI]) was assessed on preoperative lateral radiographs, and TT-TG distance was measured on preoperative axial magnetic resonance imaging (MRI) scans. Patients were grouped based on CDI and TT-TG distance, and outcomes were compared. Linear regression modeling was performed to determine whether patella alta or elevated TT-TG distance was associated with poorer PRO scores.Results:Of 165 knees in 152 patients who underwent isolated MPFL reconstruction, 115 patients (125 knees; 76%) with minimum 1-year follow-up were contacted at a mean of 5.2 years after surgery. Recurrent dislocation occurred in 5 of 125 knees (4%). Preoperative radiographs were available in 111 knees (89%), and preoperative MRI scans were available in 89 knees (71%). Mean CDI was 1.13, and 35% had a CDI ≥1.20. Mean TT-TG distance was 17.5 mm, and 26% had a TT-TG distance >20 mm. After adjusting for patient age, sex, body mass index, and graft choice, we observed that neither patella alta nor elevated TT-TG distance were associated with poorer PROs.Conclusion:Isolated MPFL reconstruction in the setting of moderately elevated TT-TG distance or patella alta was not associated with worse PROs in this cohort with relatively normal patellar tracking (no large J-sign).

Less soft tissue release in total knee arthroplasty for anteromedial compared to posteromedial knee osteoarthritis

In total knee arthroplasty (TKA), the aim of achieving a mechanically straight leg axis as well as symmetrical and equally wide gaps has become established as the gold standard in terms of surgical technique. In contrast to TKA unicompartmental knee arthroplasty (UKA) is performed in anteromedial osteoarthritis (AMOA) and does not normally require releases. This raises the hypothesis whether the type of osteoarthritis (AMOA vs. posteromedial osteoarthritis (PMOA)) determines the requirement for soft tissue releases in TKA.In this retrospective study, 114 patients with medial osteoarthritis of the knee who had been treated with a navigated total knee replacement were consecutively included. On the basis of the preoperative lateral radiographs, the patients were divided into two groups: AMOA and PMOA. The incidence and the extent of releases performed were recorded using the navigation records.Patient-specific data (gender, age) did not differ between the groups (NS). Knees with AMOA presented an overall varus alignment of 5.3 ± 3.5°, knees with PMOA 8.0 ± 4.0° (p < 0.001). 30 cases (44%) had to be released in the AMOA group, compared with 33 cases (72%) in the PMOA group (p = 0.004). In the case of medial release, the extension gap increased 3.3 ± 2.4 mm in the AMOA compared to 5.3 ± 3.7 mm in the PMOA group (p = 0.006). The medial flexion gap was released 2.2 ± 2.6 mm in the AMOA and 2.9 ± 3.0 mm in the PMOA group (p = 0.008).To achieve a neutral mechanical alignment, a release has to be performed due to asymmetry of the extension gap more often if PMOA is present than in AMOA. Surgeons should be prepared to perform more frequent and extensive medial releases in PMOA. Higher constrained implants should be available in case of unintended over release in PMOA.

Predictability of the preoperative lateral fulcrum radiograph of success in one-level vertebroplasty to treat painful osteoporotic vertebral fracture.

Restoration of height or angle has been reported following vertebroplasty (VP). The purpose of the study was to investigate the predictive value of the preoperative lateral fulcrum radiograph (LFR) of success in one-level VP for painful osteoporotic vertebral fracture. From January 2017 to January 2018, 71 patients (mean age, 76 years) receiving VP were retrospectively analyzed. Painful vertebra was defined as pseudarthrosis or edematous change in magnetic resonance imaging (MRI) scan. Fulcrum flexibility (FF) and fulcrum restoration index (FRI) of the vertebral wedge angle (VWA), regional kyphotic angle (RKA), and anterior vertebral body height (AVBH) were investigated. Back pain was evaluated using a visual analogue scale. The 30 males and 41 females were followed for an average of 21 months. The sensitivity of LFR and MRI to detect pseudarthrosis was 92% and 97%, respectively. Preoperative FF of VWA, RKA, and AVBH was 52.4%, 58.3%, and 60%, respectively, indicating similar potential restoration ability. Postoperative average FRI for VWA, RKA, and AVBH was 1.29 ± 2.98, 0.46 ± 1.16, and 1.04 ± 1.68, respectively. Final average FRI was 0.94 ± 2.96, -0.03 ± 2.25, and 0.6 ± 2.04, respectively. VWA and AVBH had better immediate restoration, and VWA had better final maintenance. All parameters progressive lost significant levels of restoration to similar degrees but without increase in back pain. LFR can help with evaluation for pseudarthrosis and the restoration effect of VP. VP had better immediate restoration of VWA and AVBH and better final VWA maintenance.

Musculoskeletal biomechanics of patients with or without adjacent segment degeneration after spinal fusion

Study designA retrospective, single center, case-control study was performed.ObjectiveThe present study employed patient-specific biomechanical modeling to find potential biomechanical differences after spinal fusion at L4/5 in patients with and without subsequent development of adjacent segment disease (ASD).MethodsThe study population comprised patients who underwent primary spinal fusion at L4/5 and were either asymptomatic during > 4 years of follow-up (CTRL; n = 18) or underwent revision surgery for ASD at L3/4 (n = 20). Landmarks were annotated on preoperative and follow-up lateral radiographs, and specific musculoskeletal models were created using a custom-built modeling pipeline. Simulated spinal muscle activation and lumbar intervertebral shear loads in unfused segments were analyzed in upright standing and forward flexion. Differences between the pre- and postoperative conditions were computed for each patient.ResultsThe average postoperative muscle activity in the upright standing posture was 88.4% of the preoperative activity in the CTRL group (p < 0.0001), but did not significantly change from pre- to postoperatively in the ASD group (98.0%). The average shear load magnitude at the epifusional joint L3/4 during upright standing increased from pre- to postoperatively in the ASD group (+ 3.9 N, +/− 17.4 (n = 18)), but decreased in the CTRL group (− 4.6 N, +/− 23.3 (n = 20); p < 0.001).ConclusionPatient-specific biomechanical simulation revealed that spinal fusion surgery resulted in greater shear load magnitude and muscle activation and therefore greater forces at the epifusional segment in those with ASD compared with those without ASD. This is a first report of patient-specific disc load and muscle force calculation with predictive merits for ASD.

Accuracy of 3 Soft Tissue Prediction Methods After Double-Jaw Orthognathic Surgery in Class III Patients.

We aimed to evaluate the accuracy and validity of conventional manual prediction method (CM) and 2-dimensional and 3-dimensional (3D) soft tissue prediction methods for Class III bimaxillary orthognathic surgery patients. Twenty skeletal Class III patients were included in this study. Soft tissue prediction was achieved with a traditional manual technique, 2-dimensional software (Dolphin Imaging, version 11.5), and 3-dimensional software (SimPlant Master, version 16.0) on preoperative lateral cephalometric radiographs and cone beam computurized tomography (CBCT) images and then compared with postoperative lateral cephalometric radiographs obtained at least 6 months after surgery (mean, 11.5 ± 6.77 months). Forty-eight measurements were done to determine the reliability of the methods. All prediction methods have limited postsurgery prediction accuracy for the subnasal upper lip area. Most of the differences were not more than 3 mm for all study groups, except the 3D software, which predicted the upper lip area to be, on average, 3.08 ± 1.38 mm further back (P < 0.001). Although the conventional method predicted 20 of 48 measurements similar to the final results, the poorest predictions were found at the nasal and labiomental areas (P < 0.001). Two-dimensional software predicted 23 of 48 measurements very close to the final results but made significantly different predictions for the nasolabial and labiomental angles, labrale superius point, and the chin area. The 3D method predicted, especially the upper lip area, to be significantly and clinically incorrect, and its soft tissue prediction was insufficient compared with the other 2 methods. The 3D software needs to be updated, especially in evaluating soft tissue A point and upper lip changes after surgery.

Skin-to-spine distance as a risk factor for surgical site infection in pediatric scoliosis surgery

Introduction: Surgical Site Infection (SSI) is a rare but serious complication following Posterior Spinal Fusion (PSF) for pediatric scoliosis. Several studies have identified patient risk factors for SSI following PSF, including high Body Mass Index (BMI). The purpose of this study was to determine whether Radiographic Skin-to-spine Distance (RSD) can be used as a surrogate for BMI when evaluating the pediatric patient’s risk of developing a SSI after PSF. Methods: This study was performed retrospectively and included patients ages 0-18 who underwent PSF for scoliosis over a four-year period. RSD, defined as the distance from the L5 spinous process to the skin, was measured using preoperative lateral radiographs. Results: Of the 176 included patients, we identified eight (4.5%) who suffered from surgical site infection following PSF. Logistic regression analysis revealed no statistically significant predictors for SSI. However, there was a strong, statistically significant linear regression prediction between RSD and BMI (r = 0.71, p=0.001). Discussion: RSD was not shown to be predictive of SSI in this patient cohort. However, the strong correlation found between RSD and BMI suggests that when assessing risk of SSI, RSD may be useful as a substitute for BMI when BMI cannot be easily ascertained.

Patient-specific statistical shape modeling for optimal spinal sagittal alignment in lumbar spinal fusion

PurposeThe present study compared patients developing ASD after L4/5 spinal fusion with a control group using a patient-specific statistical shape model (SSM) to find alignment-differences between the groups.MethodsThis study included patients who had undergone spinal fusion at L4/5 and either remained asymptomatic (control group; n = 25, follow-up of > 4 years) or required revision surgery for epifusional ASD (n = 22). Landmarks on preoperative and postoperative lateral radiographs were annotated, and the optimal spinal sagittal alignment was calculated for each patient. The two-dimensional distance from the SSM-calculated optimum to the actual positions before and after fusion surgery was compared.ResultsPostoperatively, the additive mean distance from the SSM-calculated optimum was 86.8 mm in the ASD group and 67.7 mm in the control group (p = 0.119). Greater differences were observed between the groups with a larger distance to the ideal in patients with ASD at more cranial levels. Significant difference between the groups was seen postoperatively in the vertical distance of the operated segment L4. The patients with ASD (5.69 ± 3.0 mm) had a significant greater distance from the SSM as the control group (3.58 ± 3.5 mm, p = 0.034).ConclusionPatients with ASD requiring revision after lumbar spinal fusion have greater differences from the optimal spinal sagittal alignment as an asymptomatic control group calculated by patient-specific statistical shape modeling. Further research might help to understand the value of SSM, in conjunction with already established indexes, for preoperative planning with the aim of reducing the risk of ASD.Level of evidence IDiagnostic: individual cross-sectional studies with consistently applied reference standard and blinding

Artificial intelligence clustering of adult spinal deformity sagittal plane morphology predicts surgical characteristics, alignment, and outcomes.

AI algorithms have shown promise in medical image analysis. Previous studies of ASD clusters have analyzed alignment metrics-this study sought to complement these efforts by analyzing images of sagittal anatomical spinopelvic landmarks. We hypothesized that an AI algorithm would cluster preoperative lateral radiographs into groups with distinct morphology. This was a retrospective review of a multicenter, prospectively collected database of adult spinal deformity. A total of 915 patients with adult spinal deformity and preoperative lateral radiographs were included. A 2 × 3, self-organizing map-a form of artificial neural network frequently employed in unsupervised classification tasks-was developed. The mean spine shape was plotted for each of the six clusters. Alignment, surgical characteristics, and outcomes were compared. Qualitatively, clusters C and D exhibited only mild sagittal plane deformity. Clusters B, E, and F, however, exhibited marked positive sagittal balance and loss of lumbar lordosis. Cluster A had mixed characteristics, likely representing compensated deformity. Patients in clusters B, E, and F disproportionately underwent 3-CO. PJK and PJF were particularly prevalent among clusters A and E. Among clusters B and F, patients who experienced PJK had significantly greater positive sagittal balance than those who did not. This study clustered preoperative lateral radiographs of ASD patients into groups with highly distinct overall spinal morphology and association with sagittal alignment parameters, baseline HRQOL, and surgical characteristics. The relationship between SVA and PJK differed by cluster. This study represents significant progress toward incorporation of computer vision into clinically relevant classification systems in adult spinal deformity. Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Augmented compression in exchange nailing for femoral and tibial non-unions accelerates time to radiographic union.

Exchange nailing is widely used for the management of aseptic femoral and tibial non-union. Compressive forces markedly reduce strain, increasing rate and incidence of union. Additional compressive forces can be applied to the non-union site by using the design features of some modern nailing systems. This study hypothesises that the use of additional compression in exchange nailing results in faster time to union. All femoral and tibial shaft non-unions were identified over a 4-year period between 2014-2018. Intraoperative compression during exchange nailing was either applied or not applied with a dedicated active compression device through the intramedullary nail. An initial 'radiographic union score for tibia' (RUST) score was calculated from preoperative lateral and AP radiographs and compared with the postoperative radiographs at 6-8weeks. Healing was defined as bridging callus on at least three cortices (RUST > 10). A total of 119 patients were identified. Following application of exclusion criteria, we analysed data for 19 patients, 10 undergoing exchange nailing with intraoperative compression and 9 without. The pre-exchange RUST score was comparable between the compressed group and standard exchange group with mean of 7.11 versus 7.5 (p = 0.636). At 6-8weeks post-op, there was a significant difference between the median RUST score in the compressed group vs standard exchange group, 11 compared to 8.39 (p = 0.001). Our study shows that time to union was accelerated when additional compression was applied to exchange nailing, resulting in reduced follow-up visits and number of radiographs required.

P37. Artificial intelligence clustering of adult spinal deformity morphology predicts surgical characteristics, alignment, and outcomes

BACKGROUND CONTEXT AI algorithms have shown substantial promise in medical image analysis. Previous studies of ASD clusters have analyzed alignment metrics – this study sought to complement these efforts by analyzing images of anatomical landmarks. PURPOSE We hypothesized that a neural-network-based artificial intelligence (AI) algorithm would cluster preoperative lateral radiographs of into groups with distinct morphology. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE A total of 915 patients with adult spinal deformity and preoperative lateral radiographs. OUTCOME MEASURES Schwab modifiers for SVA and PI-LL, three-column osteotomy, upper instrumented vertebrae, baseline Oswestry Disability Index, and 2-year likelihood of reaching MCID in ODI (set at -12.8). Proximal junctional kyphosis and proximal junctional failure were defined using previously published radiographic criteria. METHODS Vertebral locations for C3-L5, sacral endplate, and femoral heads were measured on lateral radiographs. Pixel locations were used to create a black-and-white overlay to the image, which was subsequently standardized for size and position using the femoral heads and sacral endplate. These images were used to train a self-organizing map (SOM). SOMs are a form of artificial neural network frequently employed in unsupervised classification tasks. RESULTS In total, 915 preoperative lateral radiographs were analyzed. A 2 × 3, toroidal SOM was trained. The mean spine shape was plotted for each cluster. Alignment, surgical characteristics, and outcomes were compared between clusters. Clusters C and D exhibited a particularly high proportion of patients with optimal (ie, modifier 0) values of PI-LL (65.0% and 68.5%) and SVA (72.8% and 53.1%). Conversely, clusters B, E, and F tended to have poor (ie, modifier ++) PI-LL (74.8%, 66.9%, and 74.6%) and SVA (75.5%, 48.6%, and 58.7%). 3-CO was most common among cluster A (26.8%), cluster B (32.6%), and cluster F (32.7%). UIV at T7-T12 was most common among cluster B (51.1%) and cluster F (60.3%). ODI CONCLUSIONS This study developed a self-organizing map that clustered preoperative lateral radiographs of ASD patients into groups with highly distinct overall spinal morphology. These clusters predicted alignment, surgical characteristics, and HRQOL. Further studies of this classification approach will expand to compare pre- and postoperative radiographs. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Standardization of lateral pelvic radiograph is necessary to predict spinopelvic mobility accurately.

Patients with abnormal spinopelvic mobility are at increased risk for instability. Measuring the change in sacral slope (ΔSS) can help determine spinopelvic mobility preoperatively. Sacral slope (SS) should decrease at least 10° to demonstrate adequate posterior pelvic tilt. There is potential for different ΔSS measurements in the same patient based on sitting posture. The purpose of this study was to determine the effect of sitting posture on the ΔSS in patients undergoing total hip arthroplasty (THA). In total, 51 patients undergoing THA were reviewed to quantify the variability in preoperative spinopelvic mobility when measuring two different sitting positions using SS for planning. A total of 32 patients had standardized relaxed sitting radiographs, while 35 patients had standardized flexed sitting images. Of the 32 patients with relaxed sitting views, the mean ΔSS was 20.7° (SD 8.9°). No patients exhibited an increase in SS during relaxed sitting (i.e. anterior pelvic tilt or so-called reverse accommodation). Of the 35 patients with flexed sitting radiographs, the mean ΔSS was only 2.1° (SD 9.7°) with 16/35 (45.71%) showing anterior pelvic tilt, or so-called reverse accommodation, unexpectedly increasing the sitting SS compared to the standing SS. Overall, 18 patients had both relaxed sitting and flexed sitting radiographs. In patients with both types of sitting radiographs, the mean relaxed sit to stand ΔSS was 18.06° (SD 6.07°), while only a 3.00° (SD 10.53°) ΔSS was noted when flexed sitting. There was a mean ΔSS difference of 15.06° (SD 7.67°) noted in the same patient cohort depending on sitting posture (p < 0.001). A 15° mean difference was noted depending on the sitting posture of the patient. Since decisions on component position can be made on preoperative lateral sit-stand radiographs, postural standardization is crucial. If using ΔSS for preoperative planning, the relaxed sitting radiograph is preferred. Cite this article: Bone Joint J 2020;102-B(7 Supple B):41-46.

Patterns of cartilage loss and anterior cruciate ligament status in end-stage osteoarthritis of the knee.

This study aims to determine the proportion of patients with end-stage knee osteoarthritis (OA) possibly suitable for partial (PKA) or combined partial knee arthroplasty (CPKA) according to patterns of full-thickness cartilage loss and anterior cruciate ligament (ACL) status. A cross-sectional analysis of 300 consecutive patients (mean age 69 years (SD 9.5, 44 to 91), mean body mass index (BMI) 30.6 (SD 5.5, 20 to 53), 178 female (59.3%)) undergoing total knee arthroplasty (TKA) for Kellgren-Lawrence grade ≥ 3 knee OA was conducted. The point of maximal tibial bone loss on preoperative lateral radiographs was determined as a percentage of the tibial diameter. At surgery, Lachman's test and ACL status were recorded. The presence of full-thickness cartilage loss within 16 articular surface regions (two patella, eight femoral, six tibial) was recorded. According to articular cartilage loss and ACL status, 195/293 (67%) were suitable for PKA or CPKA: medial unicompartmental knee arthroplasty (UKA) 97/293 (33%); lateral UKA 25 (9%); medial bicompartmental arthroplasty 31 (11%); lateral bicompartmental arthroplasty 12 (4%); bicondylar-UKA 23 (8%); and patellofemoral arthroplasty (PFA) seven (2%). The ACL was intact in 166 (55%), frayed in 82 (27%), disrupted in 12 (4%), and absent in 33 (11%). Lachman testing was specific (97%) but poorly sensitive (38%) for disrupted/absent ACLs. The point of maximal tibial bone loss showed good interclass correlation (ICC 0.797, 0.73 to 0.85 95% confidence interval (CI); p < 0.001) and was more posterior when the ACL was absent. Maximum tibial bone loss occurring at > 55% of the anterior to posterior distance predicted ACL absence with 93% sensitivity and 91% specificity (area under the curve 0.97 (0.94 to 0.99 95% CI; p < 0.001). ACL status can be reliably determined from a lateral radiograph using the location of maximal tibial bone loss. According to regions of cartilage loss and ACL status, two-thirds of patients with end-stage knee OA could potentially be treated with PKA or CPKA. Cite this article: Bone Joint J 2020;102-B(6):716-726.

A sagittal reference line using the preoperative radiograph in total knee arthroplasty.

We evaluated the accuracy of a sagittal alignment of tibial component in total knee arthroplasty (TKA) with the sagittal reference line using the preoperative radiograph. We evaluated 151 patients who underwent primary TKA with posterior cruciate substituting type implant. For 75 patients, the sagittal reference line using preoperative radiograph (group A) was used, while for 76 patients the sagittal reference using intraoperative fibular shaft line (group B) was used. The parallel line (line S) to the anatomical axis of the tibia in the lateral plain radiograph was used as the sagittal reference. The distance from line S to proximal tibia cutting area and to skin surface 20 cm distal to the cutting area was measured in preoperative radiographs. Next, the distance to the extramedullary guide rod was applied intraoperatively, reflecting the results. The intraoperative fibular shaft line was determined using the connecting line between the tip of fibular head and the lateral malleolus. The postoperative tibial component slope angle and the difference to the target slope angle were compared. The difference to the target angle was 1.8 ± 1.3° in group A, whereas the difference was 2.5 ± 1.4° in group B (p = 0.04). The patients with difference within 3° to the target angle were 78.7% in group A and 61.8% in group B (p = 0.024). The sagittal reference line using the preoperative lateral radiograph was helpful as a reference guide for the tibial slope in TKA.

Does Atherosclerosis Have Negative Impacts on Early Adjacent Segment Degeneration After Posterior Lumbar Interbody Fusion?

Study Design:Retrospective study.Objective:To examine whether atherosclerosis has negative impacts on early adjacent segment degeneration (ASD) after posterior lumbar interbody fusion using traditional trajectory pedicle screw fixation (TT-PLIF).Methods:The subjects were 77 patients who underwent single-level TT-PLIF for degenerative lumbar spondylolisthesis. Using dynamic lateral radiographs of the lumbar spine before surgery and at 3 years postoperatively, early radiological ASD (R-ASD) was examined. Early symptomatic ASD (S-ASD) was diagnosed when neurologic symptoms deteriorated during postoperative 3-year follow-up and the responsible lesions adjacent to the fused segment were also confirmed on magnetic resonance imaging. According to the scoring system by Kauppila et al, the abdominal aortic calcification score (AAC score: a surrogate marker of systemic atherosclerosis) was assessed using preoperative lateral radiographs of the lumbar spine.Results:The incidence of early R-ASD was 41.6% at the suprajacent segment and 8.3% at the subjacent segment, respectively. Patients with R-ASD had significantly higher AAC score than those without R-ASD. The incidence of early S-ASD was 3.9% at the suprajacent segment and 1.4% at the subjacent segment, respectively. Patients with S-ASD had higher AAC score than those without S-ASD, although there was no significant difference.Conclusions:At 3 years after surgery, the advanced AAC had significantly negative impacts on early R-ASD after TT-PLIF. This result indicates that impaired blood flow due to atherosclerosis can aggravate degenerative changes at the adjacent segments of the lumbar spine after PLIF.

Lateral Neck Radiography in Preoperative Evaluation of Adenoid Hypertrophy

To assess the value of lateral neck radiographs in quantifying adenoid hypertrophy to help guide treatment decisions in patients with symptoms of nasal obstruction. Retrospective review. Quantitative radiologic grading of adenoids was correlated with the intraoperative grading to select cases in agreement between the two methods. The percent airway obstruction was calculated as a ratio of adenoid size to the size of the nasopharyngeal airway near the level of the choanae on the lateral neck radiographs for adenoidectomy cases in which radiographic and intraoperative grading of adenoid size were in agreement. A total of 426 adenoidectomy cases with preoperative lateral neck radiographs were reviewed (M:F = 254:172 for age range 9 months to 16 years), and only cases in agreement between radiographic and intraoperative adenoid grading were included in radiographic analysis (N = 234). The percent airway obstruction values were significantly different between "severely obstructive" (N = 137, mean = 94.71, SD = 6.55, range [72.00; 100.00]) and "moderately obstructive" adenoid categories (N = 97, mean = 78.53, SD = 6.91, range [63.67; 98.08]), not only within clinically relevant age groups (1-3 years, 4-7 years, 8-15 years), but also for the entire data set (95% CI [14.41; 17.95], P < .0001). "Mildly obstructive" category was omitted due to small sample size (N = 4). Lateral neck radiographs can provide useful supplemental information on the degree of nasopharyngeal airway obstruction when other clinical findings do not clearly point toward adenoid hypertrophy as a primary cause of nasal obstruction. In our data set, a 65% nasopharyngeal airway obstruction represents a value two standard deviations below the mean for "moderately" obstructive adenoid category, and can be viewed as a simplified cut-off to indicate that the degree of adenoid enlargement is clinically relevant. This cut-off value can assist in evaluation of patients with symptoms of nasal obstruction. 4.