William Anderst

Background: Biomechanical cadaver studies consistently find that cervical arthrodesis leads to increased motion adjacent to the arthrodesis. However, in vivo evidence indicates adjacent segment end range motion does not reliably increase at 1 year after one‐level or two‐level cervical arthrodesis. Because changes beyond 1 year remain unknown, this study assessed the effects of one‐ and two‐level cervical arthrodesis on adjacent segment motion 3 years after arthrodesis. Methods: Sixty‐two patients were tested preoperatively (PRE), 1 year postoperatively (1YR‐POST), and 3 years postoperatively (3YR‐POST) along with 22 asymptomatic controls, who were tested once. A validated CT model‐based tracking technique was used to measure three‐dimensional (3D) vertebral motion from biplane radiographs acquired during dynamic flexion‐extension and axial rotation of the cervical spine. Adjacent segment intervertebral end range of motion (ROM) and midrange ROM (i.e. , head within 20° of neutral) were compared between one‐level and two‐level arthrodesis patients and controls after accounting for head ROM. Results: End range adjacent segment motion tended to increase over time after arthrodesis; however, significant increases were found only after two‐level arthrodesis. In contrast, midrange adjacent segment motion increased significantly after one‐ and two‐level arthrodesis and was greater than in corresponding motion segments in controls. Conclusions: Midrange adjacent segment motion may be better than end range motion for detecting early mechanical changes after cervical arthrodesis that could contribute to adjacent segment degeneration. In vivo changes in adjacent segment motion are inconsistent across patients up to 3 years after anterior cervical arthrodesis.

Background: Manual segmentation is the gold standard for segmenting bone tissue in computed tomography (CT) scans. Recently developed auto-segmentation algorithms have the potential for substantial time saving. However, most segmentation algorithms lack external validation and have not been evaluated for their robustness to pathology and age-associated bony changes. This study aimed to evaluate the accuracy of a commercially available auto-segmentation algorithm across different joints in various patient cohorts. We hypothesized that (I) auto-segmentation accuracy would not differ significantly among the individual bones composing a given joint, and (II) auto-segmentation would perform more accurately in younger, healthy subjects without known musculoskeletal pathology than in older subjects or those with known musculoskeletal pathology. Methods: This study evaluated the accuracy of a commercially available auto-segmentation software for CT scans of the knee and shoulder using manual segmentation as the reference standard for 136 knees and 59 shoulders. Scans from healthy individuals and those with musculoskeletal pathologies were included. Accuracy was evaluated through Dice similarity coefficient (DSC), 1-pixel outer edge DSC, and average surface deviation (ASD) of 3D models created from the segmented bones. Results: Auto-segmentation yielded predominantly high DSC scores for whole-bone masks (average DSC ranging from 0.905 to 0.983), although a few cases showed relatively low performance. Edge accuracy was less accurate, with average 1-pixel edge ranging from 0.376 to 0.654. Mean ASD values were within approximately 1 mm for knees and shoulders, although knee ASD differed among groups (Pvs. 0.933±0.129; Pvs. 0.957±0.022; PConclusions: The evaluated commercial auto-segmentation algorithm was rapid and demonstrated high whole-bone volumetric accuracy for CT-based knee and shoulder bone segmentation. However, boundary-level accuracy was comparatively poor. It’s possible these limitations may be overcome by developing auto-segmentation algorithms trained specifically for patients based on their age and pathology.

Background: The purpose of this study was to assess how well manual and visual assessment of foot type agree with radiographic assessment. We hypothesized that quantitative measures would have better interrater reliability than qualitative measures, and that visual assessment of foot type would be strongly correlated with radiographic assessment. Methods: Bilateral foot photographs, radiographs, and physical examination were acquired on 92 participants to assess Radiographic Arch Type, calcaneal pitch, Meary angle, Arch Index, Photo Arch Type, Radiographic Foot Posture, Foot Posture Index, and Photo Foot Posture by 5 reviewers. Correlations between measures, interrater reliability, and sensitivity/specificity were assessed using calcaneal pitch as the reference standard. Results: Interrater reliability of the photographic and radiographic measures were moderate to good (intraclass correlation coefficient 0.52-0.83). However, agreement between methods was poor, with significant variability in classification (kappa < 0.40). Overall, Radiographic Arch Type had the greatest sensitivity and specificity for identifying planus, normal, and cavus feet. Among nonradiographic parameters, photographs had the greatest sensitivity and specificity for identifying normal feet, the greatest sensitivity for identifying planus feet, and the greatest specificity for identifying cavus feet. Conclusion: Agreement between methods varied widely, suggesting that classification is dependent on methodology and cutoff values selected to discriminate among foot types. Specifically, nonradiographic methods failed to consistently classify foot type compared with calcaneal pitch and Meary angle. Level of Evidence: Level II, prospective cohort study.

Background: Chronic low back pain (cLBP) is often accompanied by changes in lumbar spine bony morphology, including osteophyte growth. Knowledge of the volume and location of osteophytes could provide insight into habitual loading that may induce symptomatic disc degeneration and serve to guide treatment. The aim of this study was to develop an automated method to calculate osteophyte volume in lumbar vertebral bodies and to evaluate the relationships between osteophyte volume and vertebral level, age, and sex. Methods: Patients with cLBP received computed tomography (CT) scans of their entire lumbar spine. Lumbar bone models were created from the segmented CT scans. A Procrustes‐based registration algorithm transformed vertebral bodies from a reference library of bones with no osteophytes to match the patient's vertebral bodies. The best‐matched reference bone was then subtracted from the original bone to create a model of the osteophytes. Osteophyte volume and location were calculated from the model, and associations were explored between osteophyte volume, vertebral level, sex, and age. Regional differences in osteophyte volume were also evaluated. Results: The osteophyte identification algorithm was validated to have a bias of −4.7 mm ³ and accuracy of 109.7 mm ³ . Osteophyte volume increased an average of 147.8 mm ³ with each caudal vertebral level. Osteophyte volume was greater in men than in women and increased between 34.3 and 47.7 mm ³ with each year of age. The superior half of L1 and L2 had 20%–35% greater osteophyte volume than the inferior half. Conclusions: Osteophyte volume increased with more caudal vertebrae, was greater in men than in women, and increased by approximately 40 mm ³ with each year of age in 264 individuals with cLBP.

Study Design.: Prospective cohort study. Objective.: To identify patient factors that predict changes in adjacent segment kinematics three years after ACDF. Summary of Background Data.: Approximately 25% of patients who undergo anterior cervical discectomy and fusion (ACDF) develop symptomatic adjacent segment disease (ASD) requiring reoperation within 10 years. Studies have found associations between ASD and patient genetics, age, BMI, psychiatric history, and preoperative disc degeneration. Few studies have linked these factors to mechanical changes to explain ASD. Methods.: Patients performed flexion/extension and axial rotation captured by biplane radiography before, one year after, and three years after ACDF (3YR-POST). Digitally reconstructed cervical radiographs were matched to the biplane radiographs to calculate intervertebral kinematics and preoperative disc height. Patient age, sex, BMI, smoking, diabetes, psychiatric history, inciting event, length of symptoms, preoperative disc bulge, and NDI were collected. Multivariate linear regression identified patient factors associated with changes in adjacent segment kinematics and NDI 3YR-POST. Results.: Sixty-two patients completed testing. Younger age (1.1° per 10 yr, 95% CI: 0.04–1.8, P =0.011), female sex (1.8°, 95% CI: 0.5–3.1, P =0.016), lower BMI (1.4° per 10 kg/m², 95% CI: 0.4–2.5, P =0.019), and no superior adjacent disc bulge (1.4°, 95% CI: 0.0–2.7, P =0.035) predicted a larger increase in superior adjacent segment flexion/extension range of motion (ROM) 3YR-POST. Lack of superior adjacent disc bulge (1.2°, 95% CI: 0.2–2.2, P =0.025) predicted a larger increase in superior adjacent segment axial rotation ROM. No patient factors were associated with changes in inferior adjacent segment ROM. Conclusion.: A greater increase in superior adjacent segment motion 3YR-POST is predicted in younger, lower BMI, female patients with healthier preoperative discs. These results support the theory that disc degeneration progresses from early instability in younger, healthier discs to stabilization in older, less healthy discs.

Background: Chronic low back pain (cLBP) is a prevalent and debilitating condition. Gaining insight into the daily experiences of those with cLBP is crucial for developing effective management. Pain and activity are typically assessed at a single time point and often rely on retrospective self‐reports, which can be prone to recall bias and may not reflect the day‐to‐day variability of these experiences. As a part of the University of Pittsburgh LB ³ P Mechanistic Research Center, this study used ecological momentary assessment (EMA) and wearable devices to collect real‐time data in a large cohort of adults with cLBP. The primary aims were to collect and characterize pain and activity profiles of individuals with cLBP. Methods: This study enrolled 1007 adults with cLBP who met the National Institutes of Health defined criteria. Over 7 days, participants were assessed in their own environment. EMA was gathered in real‐time via a custom mobile app, prompting participants three times daily to provide their perceptions of current pain intensity (0–10), pain interference (0–10), and activity level (very light to vigorous). Time of falling asleep and waking was also reported. Participants wore ActiGraph GT9X devices on their wrist and waist. A custom back sensor was also adhered to the skin over the lumbar (L5) segment. Activity counts, wear time, and step counts were calculated, utilizing algorithms provided by ActiGraph. Sensor data were filtered to include at least 4 days of 10 or more hours each. Activity counts were categorized into sedentary, light, and moderate‐to‐very‐vigorous based on Freedson Adult cutpoints. Results: Out of 1007 participants, 989 submitted EMA data (58.8 ± 16.5 years old; 40% male and 60% female; mean pain intensity at enrollment of 5.4 (SD 2.1) and a median of 5 (interquartile range [IQR] 3) on a 0–10 scale; mean PROMIS Pain Interference T ‐score at enrollment of 60.5 (SD 7.5) and a median of 61.2 (IQR 9.6)). The median reported pain intensity level from the EMA was 1 (IQR = 3), while pain interference was 3 (IQR = 3). More than half of the participants reported a median pain intensity of either 0 or 1 (54.0%) and a median pain interference between 0 and 3 (57.4%). Most participants self‐reported their activity levels as moderate (36%) or light (33%). Based on pain ratings during each day, most participants had their pain intensity (30%) and pain interference (40%) peaking in the evening. ActiGraph data from 884 wrist‐worn and 785 waist‐worn devices were analyzed. Wrist data showed a median of 1 765 325 (IQR 796 995) activity counts/day and 9575 (IQR 4228) steps/day. Waist data showed 358 390 (IQR 223 758) activity counts/day and 4114 (IQR 3146) steps/day. The percentage of daily sedentary activity was 47.3% for wrist and 72.8% for waist. The back sensor data from 586 participants showed a median of 340 345 (IQR = 223 399) activity counts/day and a median of 3695 (IQR = 2743) steps/day. The percentage of time spent in daily sedentary activity was 82.6%. Both ActiGraph devices and the back sensor indicated that the majority of the time was spent in sedentary activity level, which is lower than the activity level reported in the EMA. Conclusions: Despite having cLBP with self‐reported moderate pain levels, participants generally reported periods of relatively low levels of pain intensity and interference in their EMA. In addition, their EMA‐reported activity levels differed from the sensor data. Participants self‐reported higher levels of activity compared to the activity levels calculated by the wearable sensors. This suggests that participants overestimated their activity levels on EMA, or that the activity level cut‐points may need to be re‐evaluated for the cLBP population. Additionally, sensors placed on different body locations showed varying activity and step counts. The activity counts calculated from the waist ActiGraph and the back sensor from this cohort were lower than the average activity counts in the US adult population. Further research is needed to better quantify these differences for people with cLBP to develop a more comprehensive understanding of the pain experience.

Background: Understanding the anterior cruciate ligament (ACL) anteromedial bundle (AMB) and posterolateral bundle (PLB) elongation patterns during physiologic loading may inform graft-tensioning strategies in double-bundle ACL reconstructions. However, limited evidence exists regarding their in vivo elongation during high-impact activities. Purpose: To quantify the relative elongation of AMB and PLB during fast running and single-leg drop landing and to identify the knee flexion angle at peak elongation. Study Design: Descriptive laboratory study. Methods: Nineteen healthy athletes performed fast running and single-leg drop landing within a biplane radiography system. Tibiofemoral motion was tracked using a validated model-based tracking process that matched computed tomography–based subject-specific 3-dimensional bone models to synchronized biplane radiographs. ACL femoral and tibial attachment points were identified on magnetic resonance imaging and registered to the bone models. AMB and PLB lengths were calculated and normalized to lengths during supine computed tomography to determine relative elongation. Fast running kinematics were analyzed over the first 60% of stance (0% = initial contact, 100% = toe-off). Single-leg drop landing kinematics were analyzed from initial contact (0%) to maximum knee flexion (100%). Results: During fast running, AMB peak relative elongation was significantly greater than PLB (mean difference, 2.6%; 95% CI, 1.5-3.6; P < .001). During single-leg drop landing, PLB peak relative elongation was comparable with AMB (mean difference, –0.9%; 95% CI, –2.2% to 0.4%; P = .17). Peak relative elongation occurred at 29° (AMB) and 27° (PLB) of knee flexion during fast running (mean difference, 1.6°; 95% CI, 0.2°-3.0°; P = .029) and at 14° (AMB) and 8° (PLB) of knee flexion during single-leg drop landing (mean difference, 5.9°; 95% CI, 2.5°-9.4°; P < .001). Conclusion: AMB elongates more than PLB during fast running, whereas PLB elongates to a similar extent as AMB during single-leg drop landing. Peak elongations occur simultaneously during fast running, while PLB elongates earlier than AMB during single-leg drop landing. Clinical Relevance: These findings suggest that fixing AMB at 14° of knee flexion and PLB at a slightly lower angle may better reproduce native bundle function during high-impact activities.