METHODS: Retrospective Cohort Study.
OBJECTIVE: Single Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) is emerging as a valuable imaging test for identifying pain generators within the lumbar spine. The relationship between radiotracer uptake on SPECT/CT and anatomic biomechanical parameters has not been previously studied.
METHODS: We performed a retrospective review of all patients seen at our institution between 2021-2023 who obtained SPECT/CT scans for workup of thoracolumbar back pain. Patient data including demographic, clinical symptoms, and surgical history were collected. Radiology reports were reviewed for evidence of pathologic degeneration and increased bone metabolism on SPECT/CT. Biomechanical parameters were measured from standing scoliosis plain radiographs. Patients were stratified into two cohorts by either presence or absence of asymmetric coronal uptake on SPECT/CT.
RESULTS: 160 patients met inclusion criteria. Patients were primarily male (55%) with average age 55 ± 15 years. 87 (54%) patients demonstrated asymmetric uptake on SPECT/CT. These patients were older (P < 0.001), but with similar gender, prior fusion history, sacroiliitis, adjacent segment degeneration, and pseudoarthrosis (P > 0.05). This cohort had more disc disease, facet arthropathy, and greater degree of coronal scoliosis and coronal imbalance (P < 0.001). There were significantly more sites of uptake in the asymmetric cohort, and uptake was preferentially observed in the concavity of the lumbar curve (P < 0.001). There were no significant differences in sagittal balance or spinopelvic mismatch between cohorts (P > 0.05).
CONCLUSIONS: Asymmetric uptake on SPECT/CT was associated with coronal deformity in patients with low back pain. Further prospective studies are warranted to assess the effect of coronal deformity on pain generation.

OBJECTIVE: To evaluate different patterns of coronal deformity secondary to ankylosing spondylitis (AS), to propose relevant treatment strategies, and to assess efficacy of asymmetrical pedicle subtraction osteotomy (APSO).
METHODS: Coronal deformity was defined as coronal Cobb angle over 20º or coronal balance distance (CBD) more than 3 cm. 65 consecutive AS patients with concomitant coronal and sagittal deformity who underwent PSO were included. The average follow-up time was 40.4 months. Radiographic evaluation included coronal Cobb angle and CBD. Furthermore, sagittal parameters were used to assess magnitude and maintenance of kyphosis correction.
RESULTS: Based on curve characteristics, coronal deformity caused by AS included four different radiologic patterns: Pattern I: lumbar scoliosis; Pattern II: C-shaped thoracolumbar curve; Pattern III: trunk shift without major curve; Pattern IV: proximal thoracic scoliosis. APSO was performed for patients in Pattern I to III while conventional PSO was applied for patients in Pattern IV. Significant improvement in all the sagittal parameters were noted in 65 patients without obvious correction loss at the last follow-up. Besides, significant and sustained correction of coronal mal-alignment was identified in 59 APSO-treated patients. Rod fracture occurred in four cases and revision surgery was performed for one case.
CONCLUSIONS: According to radiologic manifestations, coronal deformity caused by AS could be categorized into four patterns. APSO proved to be a feasible and effective procedure for correction of Pattern I to III patients. Coronal deformity pattern, apex location, sagittal profile of lumbar spine and preoperative hip function should be considered for osteotomy level selection in APSO.

OBJECTIVE: The purpose of this study is to evaluate the in vivo medial and lateral joint laxities across various total knee arthroplasty (TKA) alignment categories correlated to (1) hip-knee-ankle angle, (2) proximal tibial angle and (3) distal femoral angle in a consecutive group of patients undergoing robotic-assisted TKA.
METHODS: Using ligament tensions acquired during 805 robotic-assisted TKA with a dynamic ligament tensor under a load of 70-90 N, the relationship between medial and lateral collateral ligament laxity and overall limb alignment was established. Only knees with neutral or mechanical varus alignment were included and divided into five groups: neutral (0°-3°), varus 3°-5°, varus 6°-9°, varus 10°-13° and varus ≥14°. Groups were further subdivided by the intraoperative medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). The distraction of the medial and lateral sides was compared across the various alignments using an analysis of variance.
RESULTS: The ability to distract the medial collateral ligament in extension and flexion was proportional to the degree of varus deformity, increasing from 4.0 ± 2.3 mm in the neutral group to 8.7 ± 3.2 mm in the varus ≥14° group (p < 0.0001). On the lateral side, the distraction of the lateral collateral ligament decreased in both extension (2.2 ± 2.4 vs. 1.2 ± 2.7, p < 0.0001) and flexion (2.8 ± 2.8 to 1.7 ± 3.0, p < 0.0001) with increasing native varus deformity. MPTA and LDFA had similar effects, where increasing MPTA varus and LDFA valgus increased medial distractibility in extension and flexion. There was significant variability of the stretch of the ligaments within and across all alignment categories, in which the standard deviation of the groups ranged from 2.0 to 3.0 mm.
CONCLUSIONS: This study demonstrates increased medial ligament distractibility with increasing varus deformity. However, there was significant variability in ligamentous laxity within various limb alignment categories suggesting the anatomy and soft tissue identity of the knee is complex and highly variable. TKAs seeking to be more anatomic will not only need to restore alignment but also native soft tissue tensions.
METHODS: Level III, prognostic.

OBJECTIVE: Precise preoperative planning is mandatory when a double-level osteotomy (DLO) is required to correct a severe knee deformity. Literature does not report a validated planning method regarding DLO that could be performed directly on digital radiographs using simple measurement tools. This study aims to validate a novel DLO planning method called New Mikulicz-Joint Line (NM-JL) based on essential measurement tools, in which the correction angles are induced by the predicted post-operative joint line obliquity (JLO).
METHODS: Twenty-three patients who satisfied the inclusion criteria were enrolled. NM-JL planning method was performed using basic measurement tools to detect corrective angles and gaps. The correction was then simulated using a Virtual Segmentation Software method to obtain the osteotomy fragments. Both planning procedures were performed independently and later repeated by two orthopaedic surgeons to assess the inter and intra-observer reliability.
RESULTS: The intraclass correlation coefficient (ICC) regarding corrective angles and gaps showed a significant positive correlation between the values determined using the two procedures by both raters (p < 0.05). Pearson\'s correlation analysis revealed a significant correlation between the measured results of the two planning methods. (p < 0.05). Finally, the Bland-Altman analysis showed an excellent agreement (p < 0.05) for all measurements performed.
CONCLUSIONS: The NM-JL method showed high values of intra and inter-rater reliability. The procedure is built up starting from the predicted value of post-operative joint line obliquity, allowing to maintain this parameter fixed. Other advantages include the quickness, adaptability, and possibility to be performed on any Digital Imaging and Communication in Medicine (DICOM) viewer.
METHODS: Level IV.

UNASSIGNED: To investigate the relationship between sagittal alignment and coronal deformity in patients with adolescent idiopathic scoliosis (AIS) through analysis of the spinal imaging data.
UNASSIGNED: Four hundred and fifty-four AIS patients who underwent anteroposterior and lateral radiography of the while spine were enrolled, and the spinal parameters of Cobb angle, cervical lordosis, C1-C2 angle, T1 slope, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic tilt (PT), pelvic incidence (PI), cervical sagittal vertical axis (SVA), and spinal SVA were analyzed.
UNASSIGNED: The patients were divided into two groups according to the size of the Cobb angle: group A (Cobb angle ≤45°, n=414) and group B (Cobb angle >45°, n=40). In group A, the Cobb angle was in a medium negative correlation with the cervical lordosis angle (r=-0.637, P<0.001), a weak positive correlation (|r|<0.3, P<0.05) with C1-C2 angle, T1 slope and thoracic kyphosis. In group B, the Cobb angle was in a mild positive correlation (P<0.05) with PT (r=0.398) and PI (r=0.360). The cervical lordosis angle was significantly (P<0.05) different between male and female patients in both groups. In Group A, the cervical lordosis angle was in a significantly (P<0.01) positive correlation with the T1 slope (r=0.586), thoracic kyphosis (r=0.490), and sagittal vertical axis (r=0.135), and a significantly (P<0.01) negative correlation with cervical sagittal vertical axis (r=-0.128) and C1-C2 angle (r=-0.155). In group B, the cervical lordosis angle was in a significantly (P<0.05) positive correlation with T1 slope (r=0.661), thoracic kyphosis (r=0.608), lumbar lordosis (r=0.425), sacral slope (r=0.434), and sagittal vertical axis (r=0.335).
UNASSIGNED: In AIS patients with the Cobb angle ≤45º, a significant negative correlation exists between the cervical lordosis and the Cobb angle. The sagittal morphology of the cervical spine in AIS patients is affected by the spinal coronal deformity, which plays an important role in the treatment of AIS.

Background: There is little data on the magnitude and factors for functional leg lengthening after primary total knee arthroplasty (TKA). Questions/Purpose: We sought to determine the incidence of and risk factors for functional leg lengthening after primary TKA. Methods: We retrospectively reviewed consecutive unilateral primary TKAs at a single institution from 2015 to 2018. Of the 782 TKAs included, 430 (55%) were performed in women; the mean age was 66 years, and the mean body mass index was 29 kg/m2. Preoperatively, 541 (69%) knees were varus deformities and 223 (29%) were valgus deformities. Hip to ankle biplanar radiographs were obtained preoperatively and 6 weeks postoperatively for all patients. Two independent researchers measured leg length, coronal plane deformity, lateral knee flexion angle, and overall mechanical alignment on all preoperative and postoperative radiographs. Results: The mean overall ipsilateral functional leg lengthening was 7.0 mm. Seven hundred knees (90%) were overall functionally lengthened, including 462 (59%) knees lengthened >5 mm and 250 (31%) knees lengthened 10 mm or more. A valgus deformity and coronal plane deformity of 10° or more were significant risk factors for increased functional lengthening. Patients with severe valgus deformities (>10°) had the largest amount of functional lengthening, at a mean of 13.5 mm. Conclusion: After primary TKA, 90% of limbs are functionally lengthened, including roughly one-third over a centimeter. Valgus knee deformities and severe deformities (>10°) were significant risk factors for increased limb lengthening.

UNASSIGNED: Knee instability is considered one of the most frequent cause of failure after primary total knee arthroplasty (TKA). In order to address intraoperative instability, varus-valgus constrained knee implants (VVC) are increasingly utilized in primary TKA. Despite an increased risk of mechanical failure, short to mid-term results seem to be encouraging, but long-term results are still lacking.
UNASSIGNED: A systematic review of prospective and retrospective studies that reported clinical outcomes of patients with VVC systems in primary TKAs between 1990 and 2020 was performed.
UNASSIGNED: In all, 28 articles met our inclusion criteria. A total of 2798 VVC implants were used in primary TKA. The all-cause revision-free survivorship was 95.2% at a mean follow-up of 7 years. Infection and aseptic loosening were the most common reasons for reoperation with an incidence of 1.8% and 1.7%, respectively. Overall complication rate was 9.6%, the most common complications were knee stiffness and infection with an incidence of 2.8% and 2.5%, respectively.
UNASSIGNED: VVC implants in primary TKA are associated with improved functional outcomes and good mid-term survivorship, comparable to lower level of constraint implants. Non-modular stemless seem to be reliable implants at mid-term follow-up. However, given the lack data coming from long-term studies, VVC implants should be used cautiously in primary TKA.

UNASSIGNED: A substantial coronal plane deformity is common in the context of end-stage ankle osteoarthritis. Recent literature shows a trend toward extending the indication of total ankle arthroplasty in increasingly severe coronal deformities, showing promising results when correct alignment is achieved. Nevertheless, the results of lateral transfibular total ankle replacement (LTTAR) in valgus has not been extensively studied. We aimed to evaluate if the outcomes of LTTAR in ankles with valgus deformity were similar to those with no major deformity at short-term follow-up.
UNASSIGNED: This retrospective cohort study included 228 LTTARs. Patients were classified into 2 groups according to the preoperative coronal plane tibiotalar angle (TTS): neutral (less than 10 degrees of coronal deformity, 209 patients) and valgus (above 10 degrees of valgus, 19 patients). Clinical evaluation was performed using the American Orthopaedic Foot & Ankle Society (AOFAS) score, visual analog scale (VAS), 12-Item Short Form Health Survey 12 (SF-12) regarding its Physical and Mental Component Summary items. The radiographic evaluation considered anteroposterior and lateral ankle radiographs. Complications were also registered and classified as major or minor. The minimum follow-up was 2 years.
UNASSIGNED: The average AOFAS, VAS, and SF-12 scores improved significantly postoperatively (P < .001), without differences between groups. At final radiographic follow-up, the valgus alignment group did not show significant differences with the neutral alignment group regarding TTS, lateral distal tibial angle, or anterior distal tibial angle (P > .05).
UNASSIGNED: LTTAR in cases with valgus deformity achieved and maintained correction at short-term follow-up, as obtained in neutral alignment ankles. Clinical outcomes improved significantly regardless of preoperative valgus deformity.
UNASSIGNED: Prognostic Level III, retrospective cohort study.

BACKGROUND: The purpose of this study was to evaluate (1) the reoperation rates and survivorship for septic and aseptic causes, (2) radiographic outcomes, and (3) clinical outcomes of condylar-constrained knee (CCK) implants used in primary total knee arthroplasty (TKA) with severe coronal deformity and/or intraoperative instability.
METHODS: A consecutive series of CCK implants in primary TKA was retrospectively evaluated in patients with severe coronal deformities. Forty-nine patients (54 knees) were included with a mean follow-up of 9 years (range 6-12). All patients were treated with a single-design, second-generation CCK implant. The primary diagnosis was osteoarthritis in 36 knees, post-traumatic arthritis in 7 knees, and rheumatoid arthritis in 4 knees. Preoperatively, standing femorotibial alignment was varus in 22 knees and valgus in 20 knees.
RESULTS: At a mean follow-up of 9 years, overall survivorship was 93.6%. Two knees (4.3%) required revision for periprosthetic joint infection. One knee (2.1%) required subsequent arthroscopy due to patellar clunk syndrome. At final follow-up, no evidence of loosening or migration of any implant was reported, and the mean Knee Society knee scores improved from 43 to 86 points (p < 0.001). The mean Knee Society function scores improved to 59 points (p < 0.001). The average flexion contracture improved from 7° preoperatively to 2° postoperatively and the average flexion from 98° to 110°. No knees reported varus-valgus instability in flexion or extension.
CONCLUSIONS: CCK implants in primary TKA with major coronal deformities and/or intraoperative instability provide good midterm survivorship, comparable with less constrained implants. In specific cases, CCK implants can be considered a viable option with good clinical and radiographic outcomes. However, a higher degree of constraint should be used cautiously, leaving the first choice to less constrained implants. Level of evidence Therapeutic study, level IV.

Surgical correction strategies for adult spinal deformity (ASD) relies heavily on radiographic alignment goals, however, there is often debate regarding degree of correction and how static alignment translates to physical ability in daily life. Kinematic analysis has the potential to improve the concept of ideal spinal alignment by providing clinically meaningful estimates of dynamic changes in spinal alignment during activities of daily life.
Estimate representative dynamic ranges of spinal alignment during gait among ASD patients using 3D motion tracking; compare dynamic alignment between mild and severe deformity patients and to healthy adults.
Retrospective review at a single institution.
Fifty-two ASD patients and 46 healthy adults.
Radiographic alignment, kinematic spine motion, spatiotemporal gait measures, patient reported outcomes (VAS pain, ODI, SRS-22r).
Spinal alignment was assessed radiographically and during standing and overground walking tests. Dynamic alignment was initialized by linking radiographic alignment to kinematic alignment during standing and at initial heel contact during gait. Dynamic changes in maximums and minimums during gait were made relative to initial heel contact for each gait cycle. Total range-of-motion (RoM) was measured for both ASD and healthy subjects. Dynamic alignment measures included coronal and sagittal vertical axes (CVA, SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), and pelvic tilt (PT). ASD patient\'s deformities were classified as either Mild or Severe based on the SRS-Schwab ASD classification.
Severe ASD patients had significantly larger dynamic maximum and minimums for SVA, TPA, LL, and PT (all p<.05) compared with Mild ASD patients. ASD patients exhibited little difference in dynamic alignment compared with healthy subjects. Only PT had a significant difference in dynamic RoM compared with healthy (p<.001).
Mild and Severe ASD patients exhibited similar global dynamic alignment measures during gait and had comparable RoM to healthy subjects except with greater PT and reduced spatiotemporal performance which may be key compensatory mechanisms for dynamic stabilization.