Frailty, Bone Health, and Radiographic Predictors of Complications After Long-Segment Fusion for Adult Spinal Deformity.

Retrospective cohort. This study aims to assess the effects of CT-based subsidence on lumbar sagittal alignment and patient-reported outcome measures (PROMs) after transforaminal lumbar interbody fusion (TLIF), and to determine if subsidence and cage properties are independent predictors of postoperative changes in regional lordosis. Subsidence is a well-known complication following interbody fusion and has previously been associated with recurrence of preoperative symptoms and higher reoperation rates. There is incomplete evidence to characterize the effects of subsidence on lumbar alignment and PROMs following TLIF. All adult patients who underwent 1- or 2-level TLIF at a multi-institutional academic center between 2017 and 2019 were retrospectively identified. Interbody subsidence at the superior and inferior endplate of each TLIF level was directly measured on both coronal and sagittal CT scans obtained between 6 months and 1 year postoperatively. Patients were grouped based on the maximum subsidence at each operative level: mild-moderate (<4mm) or severe (≥4mm). Preoperative, immediate (<3mo), and intermediate (>6mo) postoperative radiographic outcomes (local and global lumbar alignment) and PROMs (VAS Back, Oswestry Disability Index, PROMIS Physical Function and Mood) were collected. Univariate and multivariate analysis compared patient demographics, surgical factors, and changes in radiographic measures and PROMs across subsidence groups. Multiple linear regression analyzed independent effects of subsidence and cage characteristics on alignment. Sixty-seven patients with 85 unique fusion levels were included (55 with mild-moderate subsidence, 30 with severe subsidence). Levels with severe subsidence demonstrated significantly less regional lordosis at final follow-up than nonseverely subsided levels (6.4 vs. 9.1 degrees, P =0.032). No PROM significantly differed between severe and nonsevere subsidence subgroups. Linear regression analysis revealed that severe subsidence was a strong independent predictor of regional lordosis ( P =0.029) at final follow-up. Severe subsidence negates perioperative improvements in regional lordosis following TLIF, while changes in regional alignment are maintained in the absence of severe subsidence. Level III.

Proximal junctional kyphosis (PJK) remains a major complication after surgery for adult spinal deformity (ASD). While postoperative alignment is a recognized modifiable risk factor, objective methods for selecting the upper instrumented vertebra (UIV), a key modifiable factor, are lacking. We aimed to determine whether preoperative sagittal alignment, specifically cervicothoracic alignment, predicts the risk of PJK, and whether this risk can be mitigated by UIV selection, focusing on factors available at the time of surgical planning. From a multicentre, prospective ASD registry, we identified patients who had undergone fusion to the sacrum or pelvis and had an upper (T1-T5) or lower thoracic (T9-L1) UIV, with a two-year or more radiological follow-up, excluding those with a previous fusion over more than four levels. The primary outcome was PJK within two years. Multivariable logistic regression modelled the risk of PJK by UIV region, preoperative C2-T9 pelvic angle (PA), age, sex, and pelvic incidence, testing for interaction between UIV region and C2-T9 PA. Adjusted absolute risk reduction (ARR) and number needed to be exposed (NNEB) were calculated. Multivariable linear regression estimated two-year patient-reported outcome measures, adjusting for baseline scores, age, UIV, and PJK. A total of 627 patients across 20 centres were included (median age 66 years (IQR 59 to 70); 483 (77%) female). The UIV was lower thoracic in 380 (61%) and upper thoracic in 247 (39%) patients. PJK occurred in 149 (39%) lower thoracic and 38 (15%) upper thoracic UIV patients. There was a significant interaction (p = 0.028) between preoperative C2-T9 PA and UIV region. At a preoperative C2-T9 PA of 14° (cohort median), an upper thoracic UIV had an adjusted ARR of 36% and NNEB was 2.8. Females had an adjusted odds ratio of 1.62 (95% CI 1.03 to 2.59; p = 0.042) for PJK. Worse preoperative sagittal malalignment, measured by C2-T9 PA, was associated with a higher risk of PJK and depended on UIV region. An upper thoracic UIV in patients with high preoperative C2-T9 PA may reduce PJK.

This study explores the relationship between thoracic sagittal kyphotic alignment, quantified by the Cobb angle, and postoperative shoulder function, specifically assessing whether the presence and severity of thoracic kyphosis influence clinical outcomes and range of motion (ROM) in patients undergoing reverse shoulder arthroplasty (rTSA). A retrospective review was conducted on 110 patients who underwent rTSA from 2020 to 2022 at a single institution. Sagittal kyphosis was quantified on preoperative chest radiographs. Clinical outcomes were measured using the visual analog scale (VAS), constant score (CS), simple shoulder test, Single Assessment Numeric Evaluation (SANE) score, and pre- and postoperative ROM. Patients were separated into three groups based on Cobb angle severity (0-36°, 37-46°, ≥47°) and followed for a minimum follow-up of 2 years. A p-value <0.05 was considered statistically significant. Patients with a Cobb angle ≥47° exhibited a significant reduction in flexion (132.7° vs 149.4° for Cobb ≤36°; p = 0.031) and abduction (122.9° vs 142.1°; p = 0.035). This group also showed lower mean CSs (75.1 vs 83.3; p = 0.048). No significant differences were observed among groups in SANE or VAS pain scores. Greater thoracic kyphosis is associated with reduced functional outcomes and diminished flexion and abduction following rTSA. These findings suggest that sagittal spinal alignment may influence postoperative shoulder performance. Retrospective Cohort Comparison III.

The C3-dome, C7 reverse dome open-door laminoplasty technique preserves posterior cervical musculature and has been reported to improve postoperative cervical alignment while reducing axial neck pain and C5 palsy. This study investigates differences in postoperative dorsal cervical cord migration with this new technique compared to published data on traditional laminoplasty. A retrospective review was performed on consecutive patients who underwent C3 dome-C7 reverse dome open-door laminoplasty for cervical myelopathy. Clinical, surgical, and radiological outcomes were analyzed, with emphasis on postoperative MRI cord migration and C5 palsy. Eighty-one patients (50 males, 31 females) with at least two years' follow-up were included. Mean intraoperative blood loss was 233 ± 216 ml. The mean mJOA score improved from 12.9 ± 2.8 to 15.1 ± 1.4, with an average gain of 2.2 ± 2.0. Two patients developed superficial wound infections, managed successfully with oral antibiotics. No C5 palsy, implant failure, or revision surgery occurred. C2-7 sagittal alignment (p=0.911) and cervical range of motion (p=0.869) were unchanged postoperatively. Mean dorsal cord migration by level was: C3: 0.60 ± 0.8 mm, C3/4: 0.86 ± 1.0 mm, C4: 1.38 ± 0.9 mm, C4/5: 1.7 ± 1.0 mm, C5: 1.81 ± 1.0 mm, C5/6: 1.8 ± 1.1 mm, C6: 1.9 ± 0.9 mm, C6/7: 1.32 ± 1.0 mm, C7: 0.1 ± 1.4 mm. Compared with traditional laminoplasty, two key differences were noted: (1) the maximal cord migration apex shifted caudally to C6 (versus C5), and (2) overall dorsal migration was more controlled and reduced. This study is the first to define cord migration patterns after C3 dome-C7 reverse dome open-door laminoplasty. The caudal shift of maximal migration to C6 and reduced overall dorsal displacement likely reduces C5 root traction, potentially lowering the risk of postoperative C5 palsy. IV.

While robotic-assisted total knee arthroplasty (RA-TKA) demonstrates high precision in coronal plane alignment, its accuracy in the sagittal plane-particularly in restoring the planned posterior tibial slope (PTS)-remains suboptimal, and the influence of coronal plane alignment phenotypes on sagittal alignment accuracy is poorly understood. This dual-center, retrospective study analyzed 194 patients undergoing RA-TKA with a constrained kinematic alignment strategy. Sagittal accuracy was assessed using ΔPTS, defined as the deviation between the planned and postoperative PTS measurements, and patients were stratified into high-accuracy (ΔPTS ≤ ± 2°) and low-accuracy (ΔPTS > ± 2°) cohorts. Factors associated with inaccurate PTS reconstruction were evaluated in univariate and multivariate logistic regression. Only 40.7% of cases achieved PTS reconstruction within ± 2° of the planned target, and 72.2% of cases exhibited a postoperative PTS lower than planned. Univariate analysis identified older age, use of Chunli prosthesis, and Coronal Plane Alignment of the Knee (CPAK) Type III phenotype as significant factors. Multivariate analysis confirmed CPAK Type III as an independent risk factor for inaccurate PTS reconstruction (OR = 2.7, 95% CI: 1.056-6.901, P = 0.038). The accuracy of PTS reconstruction in RA-TKA was suboptimal in this cohort, with a prevalent tendency toward under-correction. The CPAK Type III phenotype was identified as an independent risk factor for sagittal inaccuracy, warranting phenotype-specific consideration in preoperative planning and heightened intraoperative vigilance. Based on our clinical experience, compensatory strategies such as adjusting the planned PTS according to individual patient anatomy are warranted.

Anterior cervical discectomy and fusion (ACDF) is an established procedure for treating degenerative cervical spine disease. While plate systems have been employed to optimize stability, the use of stand-alone cages was subsequently promoted to reduce plate-associated complications. The optimal stabilization strategy remains debated. This study compared clinical and radiological outcomes between both techniques. This retrospective two-center analysis examined 238 patients who underwent single-level ACDF for degenerative indications between 2012 and 2023. Stand-alone cages were used in 176 patients (73.9%) and cage-plate constructs in 62 patients (26.1%). Primary endpoints included cage subsidence (CS), pseudarthrosis, reoperations and clinical outcomes at 3 and 12 months postoperatively. Secondary endpoints comprised radiological parameters encompassing segmental (SL) and cervical lordosis (CL), as well as intervertebral height measurements. Multivariable logistic regression was adjusted for baseline differences. Cage-plate patients were older (mean difference 7 years, p < 0.001), had higher ASA grades (p = 0.017), and more frequently presented with central stenosis (p = 0.001) and myelopathy (p = 0.006). Operative time was 26min longer in the plate group (p < 0.001) while blood loss and perioperative complications were comparable. At 3 months, the stand-alone group showed significantly higher CS rates (31.8% vs. 16.1%; adjusted odds ratio [aOR] 2.54, 95% CI 1.13-5.71, p = 0.024), and had lower odds of favorable clinical outcome (aOR 0.23, 95% CI 0.08-0.72, p = 0.011). At 12 months, pseudarthrosis was markedly higher in the stand-alone group (26.7% vs. 3.2%; aOR 9.23, 95% CI 2.13-39.9, p = 0.003). The cage-plate group demonstrated superior preservation of SL (mean difference (MD) 1.7°; p = 0.036), CL (MD 5.9°; p < 0.001), and intervertebral height (all p < 0.01). Excellent/good outcomes were more frequent in the plate group (54.8% vs. 40.3%; p = 0.046), though this was short of significance after multivariable adjustment (aOR 0.48, 95% CI 0.20-1.14, p = 0.097). Additional plating in single-level ACDF was associated with reduced risk of both cage subsidence and pseudarthrosis and improved sagittal alignment at the cost of moderately increased operative time. These findings support preferential use of cage-plate constructs, particularly in elderly patients with central stenosis, myelopathy, or risk factors for pseudarthrosis.

ABSTRACTIntroductionHallux valgus (HV) can shift plantar loading, impair hallux function, and affect athletic performance in adolescent athletes. Although previous studies have focused mainly on dance‐related sports, limited data exist regarding the prevalence and radiographic morphology of HV across broader athletic populations. In particular, the role of hallux interphalangeal alignment and proximal phalanx morphology in deformity severity remains unclear. We aimed to determine HV prevalence among adolescent athletes across various sports and to identify radiographic morphological factors associated with deformity severity.MethodsThis cross‐sectional study included 280 adolescent athletes (188 males and 92 females; mean age, 13.7 ± 1.6 years) across 18 sports. Weight‐bearing foot radiographs were obtained. Radiographic parameters included the HV angle (HVA), intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), hallux interphalangeal angle (HIA), proximal–distal phalanx articular angle (PDPAA), Meary angle, calcaneal pitch angle, and medial cuneiform–fifth metatarsal height. Multivariable linear regression analyses were performed separately for dominant and nondominant feet to identify factors associated with combined deformity severity (sum of HVA and HIA).ResultsHV was identified in 42.9% of athletes when defined as HVA ≥ 15° in either foot and was more prevalent in female than male athletes (59.8% vs. 34.6%, p < 0.001). In contrast, 93.6% of athletes had an HIA ≥ 10° in either foot, based on the conventional adult‐derived threshold, with no significant sex difference. In this multi‐sport adolescent athlete population, distal first metatarsal morphology (DMAA) and proximal phalanx articular morphology (PDPAA) showed the strongest independent associations with combined deformity severity. IMA and female sex were also significant factors, whereas sagittal plane alignment, body mass index, and ankle activity score were not.ConclusionThis multi‐sport study extends previous findings on adolescent hallux deformity by demonstrating that deformity severity is associated not only with metatarsal structural factors but also with proximal phalanx articular morphology. These findings support a broader radiographic characterization of adolescent HV, although their clinical significance requires further study.

AimsTo determine the prevalence of MRI-confirmed ischiofemoral impingement (IFI) in young patients with nonarthritic hip pain, and to evaluate the associations of femoral, acetabular, pelvic, and spinopelvic parameters with IFI.MethodsWe included 250 patients with nonarthritic hip pain who underwent standardized imaging (MRI and CT, lateral standing and deep-seated spinopelvic radiographs). IFI was diagnosed by quadratus femoris oedema/atrophy. IFI-positive/negative hips were compared for morphological and spinopelvic parameters. Underlying pathologies (e.g. femoroacetabular impingement, dysplasia) were documented. Multivariate regression identified independent predictors of IFI and determinants of quadratus femoris space (QFS).ResultsIFI was identified in 14/250 patients (5.6%), all female. IFI cases had significantly reduced ischiofemoral space (24.8 mm (SD 6.7) vs 34.9 mm (SD 10.2); p < 0.001) and QFS (9.2 mm (SD 3.4) vs 20.7 mm (SD 7.0); p < 0.001). IFI cases demonstrated larger ischial angle (135.7° (SD 3.0°) vs 132.2° (SD 4.0°); p = 0.002), higher femoral version (16.5° (SD 10.3°) vs 10.4° (SD 12.3°); p = 0.031), and reduced femoral (34.2 mm (SD 5.6) vs 37.7 mm (SD 5.9); p = 0.016) and acetabular offset (29.4 mm (SD 3.5) vs 32.0 mm (SD 4.8); p = 0.036). In standing, IFI cases tended to have lower lumbar lordosis (LL) (55.31° (SD 7.95°) vs 59.91° (SD 10.50°); p = 0.077), higher pelvic tilt (15.68° (SD 4.73°) vs 12.39° (SD 6.20°); p = 0.047), and smaller mismatch between pelvic incidence and LL (–2.39° (SD 7.18°) vs –7.82° (SD 10.00°); p = 0.034). The change in LL across standing to deep-flexed sitting transition (ΔLL) was lower in IFI cases (50.31° (SD 10.89°) vs 56.89° (SD 10.64°); p = 0.020). Multivariate regression identified reduced QFS (odds ratio (OR) 1.92, 95% CI 1.30 to 2.89; p < 0.001) and greater LL (OR 1.16, 95% CI 1.00 to 1.33; p = 0.047) as independent predictors of IFI. Size of QFS was associated positively with femoral offset (β = 0.35; p < 0.001) and mismatch between pelvic incidence and LL (β = 0.18; p = 0.028), and negatively with ischial angle (β = –0.34; p < 0.001), femoral version (β = –0.14; p = 0.016), and standing pelvic tilt (β = –0.16; p = 0.026).ConclusionIFI occurred in 5.6% of patients and was characterized by a distinct morphometric and sagittal alignment profile, including increased femoral version, reduced offset, greater ischial angle, reduced LL, increased pelvic tilt, and diminished spinal motion. These findings support a multifactorial model in which hip morphology and spinopelvic alignment jointly influence posterior hip clearance in IFI.Cite this article: Bone Jt Open 2026;7(6):792–801.

The impact of postoperative cervical sagittal alignment on patient-reported outcomes following posterior decompression and fusion for degenerative cervical myelopathy: A prospective cohort study with 18 month follow-up.

Proximal junctional failure combined with symptomatic thoracic disc herniation: a rare case report.

Evidence linking backpack load to pediatric back pain is inconsistent, and imaging data under load are scarce. We quantified acute backpack-related changes in sagittal alignment using standing whole-spine radiographs in school children. Sixty-five healthy schoolchildren underwent standing lateral whole-spine radiography under three within-participant conditions: unloaded, low-load (target 10-15% body weight), and high-load (approximately 50% greater than low load). Habitual exposure (usual backpack weight and commute time) was related to unloaded alignment using multivariable linear regression, focusing on sagittal vertical axis (SVA), pelvic incidence minus lumbar lordosis (PI-LL), and pelvic tilt (PT). Load-alignment associations were examined using linear mixed-effects models with measured applied load (% body weight) as a predictor. Abnormal SVA (≥ 40mm) under loading was examined using a generalized linear mixed-effects model. Receiver operating characteristic (ROC) analysis and the area under the curve (AUC) evaluated applied load for discriminating abnormal SVA. Habitual backpack weight and commute time were not independently associated with unloaded SVA, PI-LL, or PT. Increasing applied load was associated with higher SVA and thoracic kyphosis and with lower PT, while lumbar lordosis changed minimally. Applied load increased the odds of abnormal SVA (odds ratio 1.526 per 1% increase in applied load; p < 0.001), whereas greater grip strength was protective (odds ratio 0.752; p = 0.037). ROC analysis showed an AUC of 0.725 with an optimal cut-off of 16.0% body weight. Backpack loading acutely shifts sagittal alignment forward in schoolchildren on whole-spine radiographs. Clinically meaningful pediatric thresholds under load warrant further study.

Retrospective cohort study. To compare sagittal alignment, reoperation rates, and patient-reported outcomes between anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) in patients ≤50 years. ALIF and TLIF are commonly used lumbar fusion techniques with known differences in alignment restoration and complication profiles. However, comparative outcomes in younger patients, who have greater long-term biomechanical demands, remain poorly defined. A single-institution retrospective analysis was performed on patients ≤50 years undergoing 1-2 level ALIF (stand-alone or with posterior instrumentation) or TLIF at L4-S1. Radiographic parameters (lumbar lordosis [LL], PI-LL mismatch, pelvic tilt [PT]) were assessed preoperatively and up to 2 years postoperatively. Reoperation rates and indications were recorded, with Kaplan-Meier and Cox regression analyses evaluating reoperation-free survival. Patient-reported outcomes included PROMIS Global Mental Health (GMH) and Physical Health (GPH). Multivariable regression adjusted for age, BMI, CCI, and multilevel fusion. A total of 218 patients were included (ALIF stand-alone: n=60; ALIF+posterior (ALIF +P): n=47; TLIF: n=111). At 2 years, ALIF+P demonstrated greater LL and lower PI-LL mismatch compared to TLIF (P≤0.02). Reoperation rates were highest in TLIF (20.7%) versus ALIF stand-alone (10.0%) and ALIF+P (8.5%) (P=0.03). TLIF was associated with increased reoperation risk compared to ALIF+P (HR 2.13, 95% CI 1.62-2.71). Adjacent segment disease was more common in TLIF (P=0.040). Early (6-week) GMH and GPH favored TLIF (P<0.001), whereas final GPH was highest in ALIF+P (P=0.001). Subsidence rates were similar across groups (P=0.627). In patients ≤50 years, ALIF with posterior instrumentation provides superior and durable sagittal alignment, lower reoperation rates, and improved long-term physical health compared to TLIF. Although TLIF demonstrates favorable early recovery, circumferential ALIF may offer greater long-term biomechanical and clinical benefit in younger patients.

C5 palsy is a common and disabling complication of posterior cervical decompression, impairing shoulder function, prolonging rehabilitation, and reducing patient satisfaction. Prophylactic C4/5 foraminotomy has been proposed as a preventive strategy, but its effectiveness and safety remain uncertain. To systematically assess the impact of prophylactic C4/5 foraminotomy on the incidence of C5 palsy and postoperative outcomes. We conducted a systematic review and meta-analysis of 12 comparative cohort studies (n = 2,023) following PRISMA guidelines. The primary outcome was incidence of postoperative C5 palsy. Secondary outcomes included functional scores, sagittal alignment, and perioperative parameters. Prophylactic foraminotomy significantly reduced C5 palsy risk by 67% (RR = 0.33, 95% CI: 0.21-0.52; p < 0.0001) with consistent effects across surgical techniques (I2 = 0%). Modest improvements in JOA (SMD = + 0.14, p = 0.028) and NDI (SMD = -0.15, p = 0.032) were observed, without adverse effects on sagittal alignment or blood loss. Operative time increased moderately (SMD = + 0.47, p = 0.0003). Prophylactic C4/5 foraminotomy is associated with a substantial reduction in the risk of postoperative C5 palsy, with moderate-certainty evidence supporting its clinical effectiveness. Future randomized studies may be valuable to refine patient selection and confirm generalizability across broader populations.

Most endplate lesions are asymptomatic and incidentally detected. Prevalence in adults ranges from 28% to 46%, but their clinical relevance remains unclear. A knowledge gap persists regarding how spinal alignment parameters affect the type and distribution of lesions across lumbar levels. This study aims to bridge the gap by examining associations between alignment variables and lesion indices. A retrospective study was conducted on 584 adults who underwent spine magnetic resonance imaging (MRI) and standing radiographs within 6 months, with at least one spinal level exhibiting an endplate lesion between T12-L1 and L5-S1. Lesions were graded using a validated MRI-based classification system (normal, wavy/irregular, notched, Schmorl nodes). Modic changes, sagittal alignment parameters, and lumbopelvic profile (Roussouly classification) were also evaluated. Associations between demographic and alignment variables with lesion indices were analyzed through correlation and regression models. Endplate lesions were found in 60% of spinal levels (30% wavy/irregular, 20% notched, 10% Schmorl nodes). Modic changes were absent in 84% of levels, yet 53% of these displayed lesions. Lesion severity increased with age and was slightly higher in males. Reduced lumbar lordosis correlated inversely with lesion indices, indicating a higher prevalence in flatter alignments. Severe lesions were somewhat more common in upper lumbar levels. Lumbopelvic profiles 1 and 2 showed higher lesion prevalence and severity, though profile type was not an independent predictor. Endplate lesions increase with age and reduced lumbar lordosis. While sagittal parameters and lumbopelvic profiles modulate lesion distribution, their predictive power is limited, supporting a multifactorial etiology of endplate degeneration. Endplate lesions increase with age and reduced lumbar lordosis. Although sagittal alignment and lumbopelvic profiles influence their distribution, these parameters show limited predictive value, highlighting the multifactorial nature of endplate degeneration and the need for integrated morphological and biomechanical assessment in spinal evaluation. Endplate lesions prevalence and severity increase with age, occur slightly more in upper lumbar levels, and show a weak-to-moderate Modic changes association. Reduced lumbar lordosis could predispose to endplate lesions, suggesting unfavorable load transfer across spinal segments. Lumbopelvic profile influences lesion distribution but is not an independent predictor of lesion presence or type.

To investigate whether posterior tibial slope (PTS) is associated with failure after posterior cruciate ligament reconstruction (PCLR) in a cohort of patients undergoing isolated PCLR and PCL-based multiligament knee injuries (MLKI) reconstruction. The hypothesis was that (1) a reduced PTS is a factor affecting PCLR failures in isolated PCLR, but (2) it is not in the context of PCL-based MLKI. A multicentric retrospective study was conducted across four high-volume knee surgery centres. Patients were contacted to assess the occurrence of additional surgical procedures, knee stability and satisfaction using the simple knee value (SKV). PTS of medial compartment was measured on lateral radiographs. Survival analysis was performed using the Kaplan-Meier method with failure as the endpoint (revision PCL reconstruction, persistent posterior instability documented by a positive posterior drawer test), and Cox regression was used to evaluate the association between PTS and failure. Patients were stratified according to tertiles of PTS distribution (low ≤7°, intermediate 7°-10°, high >10°). Additionally, PTS was compared between failure and non-failure groups using the Mann-Whitney U test (p < 0.05). A total of 173 patients met the inclusion criteria; 24 (13.9%) were considered failures. The overall survival rate was 86.1%, 96% at 2 years, and 70% at 15 years. PTS was slightly higher in patients who failed compared to those who did not (9.1 ± 2.3° vs. 8.0 ± 3.2°; p < 0.05). However, no significant differences in survivorship were observed across PTS tertiles. Kaplan-Meier and Cox regression analyses did not demonstrate a significant association between PTS and failure. PTS was not associated with failure after PCLR. These findings indicate that sagittal tibial alignment alone may have a limited role in determining reconstruction survivorship and do not support routine correction of PTS in primary PCLR. Level IV, retrospective cohort study.

Background: Lumbar facet joints are a significant source of chronic low back pain (CLBP), and medial branch blocks (MBBs) are the widely accepted reference diagnostic approach for diagnosis. However, clinical response varies. This study aims to investigate whether sagittal spinopelvic alignment parameters can predict the clinical efficacy of MBB in patients with facet-mediated CLBP. Methods: In this prospective observational study, 110 patients (aged 40–80) with facet-related CLBP underwent diagnostic MBBs using a double-block protocol. Spinopelvic parameters, including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and lumbar lordosis (LL), were measured on standing lateral radiographs. Clinical response was defined as a ≥80% reduction in Visual Analog Scale (VAS) scores. Data were analyzed using multivariate logistic regression and Receiver Operating Characteristic (ROC) curves. Results: Responders (n = 68) were significantly younger and had a lower BMI than non-responders (n = 42) (p < 0.05). Non-responders exhibited significantly higher PI–LL mismatch (18.6° ± 7.4 vs. 3.9° ± 4.2, p < 0.001), higher PT (23.6° ± 5.1 vs. 17.4° ± 4.5, p < 0.001), and lower LL (35.8° ± 7.2 vs. 45.2° ± 6.4, p < 0.001). ROC analysis identified a PI–LL mismatch threshold of >12.5° as the strongly associated with negative short-term diagnostic response (AUC = 0.892). Multivariate analysis confirmed that PI–LL mismatch > 12.5° was a potential associated factor within the investigated model of poor response (OR: 4.25, 95% CI: 2.10–8.60, p < 0.001), while age and BMI were not significant in the adjusted model. Conclusions: Sagittal spinopelvic malalignment, specifically an increased PI–LL mismatch, is strongly associated with reduced diagnostic utility of MBB. Integrating biomechanical assessment into clinical decision-making may improve patient selection and treatment outcomes for facet-mediated pain.

To investigate the impact of cervical paraspinal muscle characteristics on early implant subsidence following single-level anterior cervical corpectomy and fusion (ACCF). A retrospective analysis was conducted on 110 patients who underwent single-level ACCF with titanium implants. The cross-sectional area (CSA) of paraspinal muscles was measured on preoperative magnetic resonance imaging (MRI), and the deep-to-superficial extensor muscle ratio (DSR) was calculated. Sagittal alignment parameters-including C2-7 sagittal vertical axis (SVA), C2-7 Cobb angle, and C7 Slope (C7S) were also assessed. Patients were stratified into two groups based on implant subsidence (≥ 3mm segmental height loss [SH loss]). Univariate, multivariate linear and logistic regression analyses were performed to identify risk factors. Implant subsidence occurred in 19 patients (17.3%). No significant differences were found in demographic characteristics between groups. The subsidence group demonstrated significantly lower DSR at the C6 level (C6 DSR, p = 0.001) and higher C7S (p = 0.003) compared to the non-subsidence group. After adjusting for confounding variables, both C6 DSR (p = 0.006) and C7S (p = 0.014) remained significantly associated with SH loss in the multivariate linear regression model. Further multivariate logistic regression identified C6 DSR (p = 0.002) and C7S (p = 0.004) as independent predictors of subsidence. The area under the receiver operating characteristic (ROC) curve (AUC) for the model was 0.810. Reduced C6 DSR and increased C7S are significant independent risk factors for early titanium implant subsidence following ACCF. These findings underscore the importance of cervical extensor muscle balance and sagittal alignment in maintaining implant stability.

BackgroundAchieving precise reconstruction of both the coronal and sagittal planes is pivotal in total knee arthroplasty (TKA). However, conventional manual TKA (M-TKA) may induce an unintended “coronal-sagittal coupling” effect, where adjustments in one plane inadvertently alter the outcome in the other. This study aimed to quantify this iatrogenic coupling effect in M-TKA and to evaluate the potential benefits of robotic-assisted TKA (R-TKA) in decoupling these two planes and preserving sagittal Combined Flexion (CF).MethodsThis retrospective study consecutively enrolled 360 patients who underwent primary TKA between October 2023 and October 2025 (199 in the manual group and 161 in the robotic group). Pre- and postoperative coronal and sagittal parameters were measured on standing full-length lower extremity radiographs and standard lateral radiographs. The “Tibial Cutting Guide Varus/Valgus Angle” (TCVA) was defined to quantify the deviation in cutting guide placement. The study adopted a systematic stepwise analysis strategy: initially detecting potential inter-planar coupling via correlation analysis, subsequently identifying independent predictors of sagittal posterior tibial slope using linear regression models, and finally calculating the equivalent rotational mismatch angle driving this coupling from regression coefficients based on stereometric projection principles.ResultsIn the M-TKA group, ΔMPTA showed a significant negative correlation with ΔPTS (r = − 0.209, p = 0.003), an effect not observed in the R-TKA group. TCVA was a significant independent predictor of postoperative PTS in M-TKA, and geometric analysis revealed an equivalent rotational mismatch of approximately 12.4° between the cutting guide rotational axis and the prosthesis placement axis. The CF preservation rate was significantly higher in the R-TKA group than in the M-TKA group (60.9% vs. 22.6%, p < 0.001). Additionally, ΔDFF and ΔPTS showed a significant negative correlation within the R-TKA group, demonstrating a unique intra-sagittal compensatory mechanism.ConclusionConventional M-TKA exhibits an iatrogenic coronal-sagittal coupling effect, whereby coronal plane correction errors are projected onto the sagittal plane through inherent rotational mismatch and cutting guide tilt, with error magnitude positively correlated with deformity severity. R-TKA effectively decouples these two planes and better preserves the native sagittal geometric alignment through femoral-tibial synergistic adjustment.Level of evidenceLevel III, a retrospective cohort study.Supplementary InformationThe online version contains supplementary material available at 10.1186/s42836-026-00398-3.

Study designRetrospective cohort study.ObjectiveTo determine whether increased pedicle screw use in the lower subaxial cervical spine (C5-C7) improves sagittal alignment after posterior-anterior-posterior (PAP) surgery.MethodA total of 108 patients who underwent posterior-anterior-posterior (PAP) surgery for multilevel cervical degenerative disease were retrospectively reviewed. Patients were divided into three groups according to the distal fixation level: Group 1, pedicle screw fixation limited to C7; Group 2, pedicle screw fixation limited to C6-7; and Group 3, pedicle screw fixation extending to C5-6-7. Cervical sagittal alignment and patient-reported outcomes were evaluated preoperatively, immediately postoperatively, at 3months, and at 1year.ResultsBaseline sagittal parameters were similar among groups. CL increased in all groups but was significantly greater in Groups 2 and 3 than in Group 1 postoperatively (21.8° and 26.1° vs 14.2°) and at 1year (22.3° and 26.0° vs 14.8°; P < 0.05). T1S-CL decreased significantly in Groups 2 and 3 but not in Group 1 at 3months (8.5° and 3.4° vs 16.6°; P < 0.001) and at 1year (7.7° and 7.3° vs 17.8°; P < 0.001). Group 1 showed greater vertical height loss (3.9 vs 2.3 and 2.2mm; P = 0.016) and higher subsidence rates. C2-7 SVA, C2 SVA, and clinical scores improved in all groups without between-group differences.ConclusionsGreater use of pedicle screws at C5-C7 enhanced sagittal alignment correction compared with C7-only fixation, while clinical outcomes were similar across groups.