Postoperative Alignment Research Articles

Incidence of Cervical Kyphosis and Factors Associated with Improvement in Postoperative Cervical Spinal Alignment in Idiopathic Scoliosis with Major Thoracolumbar/Lumbar and Thoracic Curves.

Background: This study aimed to compare the incidence and severity of cervical kyphosis before and after surgery between patients with adolescent idiopathic scoliosis (AIS) with major thoracolumbar/lumbar curves (Lenke type 5C group) and those with major thoracic curves (Lenke type 1A group). Further, factors associated with cervical spinal alignment changes after surgery in the two groups were examined. Methods: This study included consecutive patients with AIS who underwent posterior spinal fusion for Lenke type 1A and 5C curves and who were followed up for at least 1 year. To measure changes in sagittal alignment, all patients underwent radiography before, immediately after, and at 1 year after surgery. The correlation coefficients change the value of the C2-C7 angle before and after surgery (ΔC2-ΔC7) and other spinopelvic parameters were examined. Results: In total, 19 of 30 patients in the Lenke type 1A group and 21 of 36 in the Lenke type 5C group presented with cervical kyphosis preoperatively. Hence, the incidence of cervical kyphosis did not significantly differ between the two groups. Further, the two groups had significantly higher thoracic kyphosis (TK) and greater C2-C7 angles postoperatively. The TK of the Lenke type 5C group further increased at 1 year postoperatively. The Lenke 1A type group presented with a significant re-decrease in the C2-C7 angle at 1 year postoperatively. However, the C2-C7 angle of the Lenke type 5C group did not change. The ΔTK was closely associated with the ΔC2-ΔC7 in the Lenke type 1A group, but not in the Lenke type 5C group. Conclusions: In thoracic AIS, postoperative cervical alignment should achieve an adequate TK and promote correction of the coronal plane curve. Moreover, selective corrective surgery can improve postoperative cervical alignment in lumbar AIS.

Postoperative Medial Malleolar Fractures in Total Ankle Replacement Are Associated With Decreased Medial Malleolar Width and Varus Malalignment: A Case-Control Study.

There are limited data regarding risk factors associated with periprosthetic medial malleolar fractures in total ankle arthroplasty (TAA). This case-control study aimed to identify the risk factors and analyze the effect of prophylactic screw fixation in preventing a medial malleolar fracture after TAA. A case-control study was conducted on 149 patients who underwent primary TAA. Twenty patients with postoperative medial malleolar fractures >4 weeks postoperatively (cases) were identified. An additional 129 patients (controls) were randomly selected from the TAA database. Radiographic evaluation included tibial component coronal alignment and postoperative medial malleolar width. Demographics and radiographic variables were compared between cohorts. Logistic regression was used to investigate the association between medial malleolar fracture and postoperative coronal alignment, medial malleolar width, and prophylactic fixation of the medial malleolus. Mean (SD) medial malleolar width was significantly smaller in the fracture cohort (8.52 mm [1.6]) than in the control group (11.78 mm [1.74]) (P < .001). Mean (SD) tibial component coronal alignment was 92.17 degrees (2.77) in the fracture cohort and 90.21 degrees (1.66) in the control group (P = .002). Regression analysis identified a significant negative association between postoperative medial malleolar width and the probability of fracture (OR = 0.06, 95% CI 0.01, 0.26, P < .001). Varus malalignment of the tibial component was positively associated with the probability of fracture (OR = 1.90, 95% CI 1.27, 2.86, P = .002). Prophylactic screw fixation resulted in more than 90% reduction in the odds of a fracture (OR = 0.04, 95% CI 0.01, 0.45, P = .01). ROC curve analysis determined a medial malleolar width of 10.3 mm as a potential threshold for predicting fracture. Decreased medial malleolar width and postoperative varus malalignment were associated with an increased risk of postoperative medial malleolar fracture. Therefore, surgeons should consider prophylactic screw fixation in patients with a medial malleolar width <10.3 mm or at risk of postoperative varus deformity.

Extraocular Muscle Transplantation Surgery for Primary Treatment of Extra Large-angle Squint.

Large-angle horizontal ocular deviations will commonly require bilateral surgery to correct the primary ocular deviation. However, considering the need for full correction with one surgical procedure and patients' reluctance to be operated on the good eye, such large horizontal ocular deviations may be managed with true muscle transplantation. The authors present a case series of patients who underwent this procedure and develop a surgical table to guide management. Patients with horizontal squints measuring 80 prism diopters (PD) or larger in all age groups who underwent extraocular muscle transplantation surgery between January 2019 and June 2022 in Nigeria were included. Preoperative deviation of the squint, sensory evaluation, surgical dosage, and outcomes were documented. Part of the resected muscle was transplanted to give additional recession in the antagonist muscle. Success was defined as deviation corrected by 60% or more or postoperative ocular alignment within 10 PD or less, six weeks postoperatively. Fourteen patients with extra-large-angle strabismus were operated. Male/female ratio was 0.6:1. Mean preoperative deviation of 89.6 9.3 collapsed to 6.6 1.8 PD at six weeks and continued to improve to a mean deviation of 2.5 PD at six months postoperatively. When the subgroup of patients who were 18 years were analyzed, the outcome was equally successful; preoperative deviation of 89.4 PD collapsed to 1.4 PD, six months postoperatively. There were equal success rates when those with sensory strabismus were compared with those with binocular vision; preoperative deviation of 92.5 PD in the sensory group and 88.5 PD in the binocular group collapsed to 5.9 PD and 1 PD, respectively, six months after surgery. A viable alternative for treating extra-large-angle strabismus in adults and children in developing countries was described with good postoperative outcome. In addition, a new expanded surgical dosage table for muscle transplantation surgery corrections of up to 130 PD was developed.

The amount of femorotibial alignment correction through total knee arthroplasty may affect postoperative hindfoot alignment.

This study was performed to investigate the relationship between the amount of femorotibial alignment correction and the amount of improvement of hindfoot alignment in total knee arthroplasty (TKA). A total of 159 knees undergoing TKA in 120 patients were assessed preoperatively and at 2 weeks, 1 month, 3 monthsand 6 months postoperatively. Standing hindfoot alignment was evaluated using the leg-heel angle (LHA). The amount of change in hindfoot alignment was compared between patients with severe varus knee (Group 1) and those with moderate varus, neutralor valgus knee (Group 2). The mean values of pre- and postoperative hip-knee-ankle (HKA) angle were -14 ± 4° and -1 ± 3° in Group 1 and -7 ± 5° and -1 ± 3° in Group 2, respectively. The differences between pre- and postoperative LHA were significantly larger in Group 1 than in Group 2 at 2 weeks, 1 monthand 3 months postoperatively (p = 0.006, 0.001and 0.03, respectively). At 6 months postoperatively, no differences were observed between the two groups (p = 0.31). The amount of change in hindfoot alignment was larger in Group 1 than in Group 2 at 2 weeks, 1 monthand 3 months after TKA, but there was no significant difference between the two groups at 6 months after TKA. Prognostic Level II.

Two-year outcomes of internal fixation with femoral neck system in patients with femoral neck fracture in an Asian population

BackgroundFemoral neck fractures (FNF) are one of the most common fractures, with a projected increase in incidence with population growth and ageing. The Femoral Neck System (FNS) launched in 2019 was developed specifically for fixation of FNF with the purported advantages of providing both angular and rotational stability. We report our experience with the FNS and evaluate its effectiveness and associated complications. MethodsA retrospective case series of 50 patients who underwent surgical fixation for FNF from August 2020 to October 2021 using the FNS in two Singapore tertiary institutions with at least 2 years follow-up were included. Clinical data (patients’ demographics, fracture classification, intra-operative and post-operative complications) were reviewed. Radiological analysis assessed the pre- and immediate post-operative garden alignment index (GAI) and presence of femoral neck shortening at 3 months. ResultsThe mean age was 63.5 years (SD 16.9, range 26–92). Five (10 %), 34 (68 %) and 11 (22 %) were ASA 1, 2 and 3 respectively. Twenty-four (48 %), 16 (32 %), 4 (8 %), and 6 (12 %) patients sustained Garden's 1, 2, 3 and 4 FNF respectively. The mean operative duration was 66.2 min (SD 20.5) and length of stay was 6.9 days (SD 4.6).The post-operative improvement in garden alignment index (GAI) was a mean of 9.1° (p < 0.001) on lateral view. The mean femoral neck shortening was 1.97 mm (SD 5.3) at 3 months. There were no intra-operative complications. Post-operatively, 1 (2 %) patient required blood transfusion, 1 (2 %) patient had implant cut-out and non-union managed non-operatively, 2 (4 %) patients developed avascular necrosis and required revision to total hip replacements. There were two (4 %) cases of 1-year mortality. ConclusionThe FNS achieved good outcomes with low rates of complications. The promising results justify its continued use and further evaluation in comparison to other devices.

Inverse kinematic total knee arthroplasty using conventional instrumentation restores constitutional coronal alignment.

Restricted inverse kinematic alignment (iKA) is a contemporary alignment strategy for total knee arthroplasty (TKA), commonly performed with robotic assistance. While superior clinical results are reported for kinematic-type alignment strategies, registry data indicate no survivorship benefit for navigation or robotic assistance. This study aimed to determine the efficacy of an instrumented, restricted iKA technique for achieving patient-specific alignment. Seventy-nine patients undergoing 84 TKAs (five bilateral procedures) using an iKA technique were included for preoperative and postoperative lower limb alignment analysis. The mean age was 66.5 (range: 43-82) with 33 male and 51 female patients. Artificial intelligence was employed for radiographic measurements. Alignment profiles were classified using the Coronal Plane Alignment of the Knee (CPAK) system. Preoperative and postoperative alignment profiles were compared with subanalyses for preoperative valgus, neutral and varus profiles. The mean joint-line convergence angle (JLCA) reduced from 2.5° to -0.1° postoperatively. The mean lateral distal femoral angle (LDFA) remained unchanged postoperatively, while the mean medial proximal tibial angle (MPTA) increased by 2.5° (p = 0.001). By preservation of the LDFA and restoration of the MPTA, the mean hip knee ankle angle (HKA) moved through 3.5° varus to 1.2° valgus. The CPAK system was used to visually depict changes in alignment profiles for preoperative valgus, neutral and varus knees; with 63% of patients observing an interval change in classification. Encouraged by the latest evidence supporting both conventional instrumentation and kinematic-type TKA strategies, this study describes how a restricted, conventionally instrumented iKA technique may be utilised to restore constitutional lower limb alignment. Level III.

Pre-contoured patient-specific rods result in superior immediate sagittal plane alignment than surgeon contoured rods in adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) surgery typically involves posterior spinal fusion (PSF) using rods contoured by the surgeon, which may be time-consuming and may not reliably restore optimal sagittal alignment. However, pre-contoured patient-specific rods may more optimally restore sagittal spinal alignment. This study evaluates the radiographic outcomes of AIS patients who underwent PSF utilizing surgeon contoured vs. pre-contoured rods. This is a retrospective cohort study of AIS patients who underwent PSF with either surgeon contoured or pre-contoured rods. Demographics, Lenke classification, fused levels, osteotomies, estimated blood loss (EBL), and surgical time were also obtained via chart review. Coronal curve magnitude, T5-T12 thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), PI-LL mismatch, and T1 pelvic angle (TPA) were obtained pre-operatively, postoperatively and at last follow up. Outcome measures included rate of achievement of postoperative radiographic alignment goals (TK between 20 and 40 degrees, PI-LL mismatch within 10 degrees, and TPA <14 degrees). Predicted post-operative sagittal alignment was also compared with observed measurements. Student's and paired t-tests were performed to determine significant mean differences for continuous variables, and chi-square for categorical variables. No differences were found in demographics, Lenke classification, preop radiographic measurements, fused levels, osteotomies, EBL, and surgical time in the surgeon contoured cohort (n=36; average follow up 11.3 months) and pre-contoured cohort (n=22; average follow up 9.7 months). At last follow up, 95.5% of patients with pre-contoured rods vs. 61.1% of patients with surgeon contoured rods (P=0.004) met TK goal. During assessment of first standing postoperative X-ray, 72.7% of patients with pre-contoured rods vs. 33.3% of patients with surgeon contoured rods met PI-LL mismatch goal (P=0.004). Other radiographic measurements were similar. Artificial intelligence (AI) predicted and observed differences for the pre-contoured group were 3.7 for TK (P=0.005), -7.6 for PI-LL mismatch (P=0.002), and -2.6 for TPA (P=0.11). AI and pre-contoured rods help achieve global sagittal balance with high accuracy and improved kyphosis restoration and PI-LL mismatch than surgeon contoured rods in AIS patients.

Anterior cervical hybrid constructs reduce superior adjacent segment burden compared to multilevel anterior cervical discectomy and fusion.

Traditional surgical treatment for symptomatic cervical degenerative disc disease is anterior cervical discectomy and fusion (ACDF), yet the increased risk of adjacent segment degeneration (ASD) requiring additional surgery exists and may result in limiting long-term surgical success when it occurs. Disc arthroplasty can preserve or restore physiologic range of motion (ROM), decreasing adjacent level stress and subsequent surgery. For patients with multilevel pathology requiring at least a 1-level fusion, interest is growing in anterior cervical hybrid (ACH) surgery as a partial motion-preserving procedure to decrease the adjacent level burden. This radiographic study compares postoperative superior adjacent segment motion between ACH and ACDF. Secondarily, total global motion, construct motion, inferior adjacent segment motion, and sagittal alignment parameters were compared. This is a single-center, multi-surgeon, retrospective cohort study of 2- and 3-level ACH and ACDF cases between 2013 and 2021. Degrees of motion were analyzed on flexion/extension views using Cobb angles to measure global (C2-C7) construct and adjacent segment lordosis. Neutral lateral X-rays were analyzed for alignment parameters, including global lordosis, cervical sagittal vertical axis (cSVA), and T1 slope (T1S). Differences were determined by independent t-test and Fisher's exact test. Of 100 patients, 38% were 2-level cases (47% ACH, 53% ACDF) and 62% were 3-level cases: (52% ACH, 48% ACDF). Postoperatively, superior adjacent segment motion increased with ACDF and decreased with ACH (-1.3°±5.3° ACH, 1.6°±4.6° ACDF, P=0.005). Postoperatively, the ACH group had greater ROM across the construct (16.3°±8.7° ACH, 4.7°±3.3° ACDF, P<0.001) and total global ROM (38.0°±12.8° ACH, 28.0°±11.1° ACDF, P<0.001). ACH resulted in a significant reduction of motion loss across the construct (-10.0°±11.7° ACH, -18.1°±10.8° ACDF, P<0.001). Postoperative alignment restoration was similar between both cohorts (-2.61°±8.36° ACH, 0.04°±12.24° ACDF, P=0.21). Compared to ACDF, hybrid constructs partially preserved motion across operative levels and had greater postoperative global ROM without increasing superior adjacent segment mobility or sacrificing alignment restoration. This supports the consideration of ACH in patients with multilevel degenerative cervical pathology requiring at least a 1-level fusion and suggests a propensity for long-term success by reducing the superior adjacent segment burden.

Effects of intraoperative hinge fracture on postoperative cervical spine alignment in double door cervical laminoplasty

Introduction Hinge fracture and cervical kyphosis are known complications of cervical laminoplasty. Prior literatures on hinge fracture focused mainly on laminoplasty performed using the open-door technique. In this study we aim to assess the effect of intraoperative hinge fracture on postoperative cervical spine alignment in cervical laminoplasty performed using the double door technique. Methods This study recruited patients who received double door cervical laminoplasty from January 2014 to December 2022. The diagnosis, demographic data, preoperation and postoperation cervical spine alignment of the patients with intraoperative hinge fracture were compared with patients withouintraoperative hinge fracture. Cervical spine alignment was measured using C2–7 Cobb's angle on neutral lateral cervical spine X ray. Results Nine patients with intraoperative hinge fracture and 51 patients without intraoperative hinge fracture were recruited into the study. There was no statistically significant difference in age, sex, diagnosis and preoperative cervical spine alignment between the patients with and without intraoperative hinge fracture. Significant difference was found in the postoperation cervical spine alignment (1.9 ± 15.5° vs 9.7 ± 13.6°, p = .044) and change in cervical spine alignment (−12.9 ± 12.1° vs −4.0 ± 10.0, p = .02) between patients with and without intraoperative hinge fracture. Conclusions In double door cervical laminoplasty, intraoperative hinge fracture is associated with development of postoperative cervical kyphosis.

Effect of 4-week preoperative prism adaptation in preventing postoperative residual esotropia.

Preoperative prism adaptation (PPA) simulates postoperative status and possibly can predict postoperative undercorrection before surgery in esotropia. The present study aimed to assess the effect of 4-week PPA in preventing postoperative residual esotropia. Seventy-five (75) esotropes who had undergone surgery at a single strabismus center were retrospectively enrolled. They included 25 basic, 31 acute comitant, 10 partially accommodative, and 9 recurrent esotropia patients. The preoperative deviation angle, which had been determined using the alternating prism and cover test, was fully corrected with press-on prisms 4 weeks before surgery. If there was an increase of 5 PD or more of esodeviation, the prisms were changed accordingly at 2 weeks. The deviation angle measured at 4 weeks was determined as the surgical target angle. Patients were then divided into increase (≥ 5 PD increase of angle during 4-week PPA) and non-increase groups. Success was defined as either esodeviation of 8 PD or under or exodeviation of 5 PD or under at distance at postoperative 6 months. The increase group included 44 patients (58.7%). The mean deviation angle before PPA was 27.4 PD, and after the 4-week PPA, there was an average increase of 9.4 PD. The success rate was 90.9% in the increase group and 96.8% in the non-increase group (p = 0.316). There were no intergroup differences in preoperative clinical characteristics, esotropia types, postoperative deviation angle or postoperative near stereopsis (p > 0.05). The results of this study indicated a beneficial effect of 4-week PPA in esotropia of various types, specifically by uncovering the hidden esodeviation in the increase group and simulating the postoperative alignment in both the increase and the non-increase groups.

Postoperative improvement in patient-reported outcomes after neutral alignment medial open wedge high tibial osteotomy for medial compartment knee osteoarthritis in patients aged ≥70 years versus younger patients.

To compare the postoperative clinical and radiological outcomes in patients aged ≥70 years following neutral alignment medial opening-wedge high tibial osteotomy (NA-MOWHTO) for medial compartment knee osteoarthritis (KOA) to those observed in younger patients. The data of patients who underwent NA-MOWHTO for medial compartment KOA between September 2018 and June 2022 were retrospectively analysed. The patients were categorised into groups Y (<70 years) and O (≥70 years). Age, sex, Kellgren-Lawrence classification, pre- and postoperative mechanical axis, weight-bearing line ratio, medial proximal tibial angle, preoperative Tegner Activity Score and pre- and postoperative Lysholm scores were compared between the groups. Overall, 81 patients (60 and 21 in groups Y and O, respectively) who underwent NA-MOWHTO were included in this study. No significant differences were found in patient characteristics between the two groups, except for the preoperative Tegner Activity Score, which was significantly higher in group Y than in group O (3 [2-4] vs. 2 [2-2], respectively; p = 0.011). The two groups exhibited no significant differences in pre- and postoperative knee alignments. Postoperatively, Lysholm scores improved significantly in both groups without significant differences. Additionally, no correlation was found between age and pre- and postoperative Lysholm scores. The postoperative improvement following NA-MOWHTO for medial compartment KOA is comparable in patients aged ≥70 and younger. Level III, Retrospective comparative study.

Change of cervical flexion range of motion influences postoperative sagittal alignment of the cervical spine after laminoplasty

ObjectiveThe relationships between preoperative cervical spine range of motion (ROM) and postoperative cervical sagittal alignment (CSA), and clinical outcomes after laminoplasty (LMP) have been widely studied. However, the impact of ROM changes on postoperative CSA and clinical outcomes after LMP remains unclear. Herein, patients with cervical spondylotic myelopathy (CSM) were retrospectively analyzed to explore the association between postoperative cervical ROM changes and CSA and surgical outcomes.MethodsPatients who underwent cervical LMP at our hospital between January 2019 to June 2022 were retrospectively reviewed. CSA parameters were measured before the surgery and at the final follow-up. Loss of cervical lordosis (LCL) was defined as preoperative cervical lordosis (CL) - postoperative CL. An increase in the cervical sagittal vertical axis (I-cSVA) was defined as postoperative cervical sagittal vertical axis (cSVA) - preoperative cSVA. We defined the changes in cervical flexion range of motion (△Flex ROM, preoperative Flex ROM minus postoperative Flex ROM) > 10° as L- Flex ROM group, and △Flex ROM ≤ 10° as S- Flex ROM group. Japanese Orthopedic Association (JOA) score and visual analog score (VAS) were used to assess the surgical outcomes.ResultsThe study comprised 74 patients and the average follow-up period was 31.83 months. CL, total ROM, and Flex ROM decreased and cSVA increased after cervical LMP. LCL and I-cSVA were positively correlated with △Flex. Multiple linear regression analysis showed that a decrease in the Flex ROM was a risk factor for LCL and I-cSVA after LMP. LCL and I-cSVA were higher in the L-Flex ROM group than in the S-Flex ROM group. Postoperative JOA and the JOA recovery rate were worse in the L-Flex ROM group than in the S-Flex ROM group.ConclusionsCervical total and Flex ROM decreased after cervical LMP. The reduction of Flex ROM was associated with LCL and I-cSVA after surgery. The preservation of cervical Flex ROM helps maintain CSA after LMP. Therefore, more attention should be paid to maintaining cervical ROM to obtain good CSA and surgical effects after cervical LMP.

Enhancing soft tissue balance: Evaluating robotic-assisted functional positioning in varus knees across flexion and extension with quantitative sensor-guided technology.

Functional implant positioning (FIP) for total knee arthroplasty (TKA) is an evolution of kinematic alignment based on preoperative CT scan and robotic-assisted technology. This study aimed to assess the ligament balancing of image-based robotic-assisted TKA in extension, mid-flexion and flexion with an FIP using intraoperative sensor-guided technology. The hypothesis was that image-based robotic-assisted TKA performed by FIP would achieve ligament balancing all along the arc of knee flexion. This prospective monocentric study included 47 consecutive patients with varus knees undergoing image-based robotic-assisted TKA performed with FIP. After robotic-assisted bone cuts, trial components were inserted, and soft tissue balance was assessed using sensor-guided technology at 10°, 45° and 90° of knee flexion. A mediolateral balanced knee was defined by an intercompartmental pressure difference (ICPD) ≤ 15 lbf and medial and lateral compartment pressure ≤60 lbf. The mean age was 71.6 years old ±6.7, the mean BMI was 29.0 kg/m2 ± 4.9 and the mean preoperative HKA was 174° ± 5 [159; 183]. The mean postoperative knee alignment was 177.0° ± 2.2° [172; 181]. There were 93.6% of balanced knees (n = 44) at 10 and 90° of knee flexion versus 76.6% (n = 36) at 45° of knee flexion with a significant difference (p = 0.014). Median ICPD at 10, 45 and 90° of knee flexion were, respectively, 7.0 (interquartile range [IQR]: 9), 11.0 (IQR: 9.5) and 8.0 (IQR: 9.0). Pairwise analyses revealed differences for ICPD at 45° versus ICPD at 10° (p = 0.003) and ICPD at 90° versus ICPD at 45° (p = 0.007). FIP with an image-based robotic-assisted system allowed the restoration of a well-balanced knee at 10° and 90° of flexion in varus knees. Nevertheless, some discrepancies occurred in midflexion, and more work is needed to understand ligament behaviour all along the arc of knee flexion. Level II.

Neutral to slightly undercorrected mechanical leg alignment provides superior long-term results in patients undergoing matrix-associated autologous chondrocyte implantation.

The aim of this study was to evaluate the role of leg alignment on long-term clinical outcomeafter matrix-associated autologous chondrocyte implantation (M-ACI) and to define an individualized target range to optimize clinical outcome. The present study examined patients who underwent M-ACI of the femoral condyle. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) were used to assess the results. Clinical outcomes were related to Patient Acceptable Symptomatic State (PASS). For intra- and interobserver reliability of mechanical tibiofemoral angle, mechanical medial proximal tibial angleand mechanical lateral distal femoral angle, we calculated intraclass correlation coefficientsusing a two-way mixed model with absolute agreement. A regression model and receiver-operating characteristics curve were used to identify an individual range of alignment where a favourable clinical outcome could be expected in the long term. Additional osteotomy was performed in 50% of patients with similar clinical outcomes as physiologically aligned patients (p > 0.05). The curve-fitting regression model identified a target range of -2.5° valgus to 4.5° varus for ideal postoperative alignment (R2 = 0.12, p = 0.01). Patients within this range were more likely to achieve PASS (70% vs. 27%, p = 0.001). In medially treated defects, a refined range of -2.5° valgus to 4° varus alignment was found (R2 = 0.15, p = 0.01). These patients were more likely to achieve PASS (67% vs. 30%, p = 0.01) and showed favourable postoperative KOOS and MOCART scores (p = 0.02). Patients with lateral defects were more likely to achieve PASS within a range of -2° valgus and 0.5° varus (90% vs. 45%, p = 0.03) and showed favourable postoperative KOOS and MOCART scores (p = not significant). An individual range of leg alignment-whether achieved by osteotomy or physiologic alignment-should be respected in M-ACI treatment. A neutral to slightly undercorrected alignment favours the postoperative outcome after M-ACI. When planning surgery for patients with focal cartilage defects of the femoral condyle, these ranges should be recognized as critical factors. Level III.

Comprehensive assessment of global spinal sagittal alignment and related normal spinal loads in a healthy population

Abnormal postoperative global sagittal alignment (GSA) is associated with an increased risk of mechanical complications after spinal surgery. Typical assessment of sagittal alignment relies on a few selected measures, disregarding global complexity and variability of the sagittal curvature. The normative range of spinal loads associated with GSA has not yet been considered in clinical evaluation. The study objectives were to develop a new GSA assessment method that holistically describes the inherent relationships within GSA and to estimate the related spinal loads.Vertebral endplates were annotated on radiographs of 85 non-pathological subjects. A Principal Component Analysis (PCA) was performed to derive a Statistical Shape Model (SSM). Associations between identified GSA variability modes and conventional alignment measures were assessed. Simulations of respective Shape Modes (SMs) were performed using an established musculoskeletal AnyBody model to estimate normal variation in cervico-thoraco-lumbar loads.The first six principal components explained 97.96% of GSA variance. The SSM provides the normative range of GSA and a visual representation of the main variability modes. Normal variation relative to the population mean in identified alignment features was found to influence spinal loads, e.g. the lower bound of the second shape mode (SM2-2σ) corresponds to an increase in L4L5-compression by 378.64 N (67.86%).Six unique alignment features were sufficient to describe GSA almost entirely, demonstrating the value of the proposed method for an objective and comprehensive analysis of GSA. The influence of these features on spinal loads provides a normative biomechanical reference, eventually guiding surgical planning of deformity correction in the future.

Projections of Single-level and Multilevel Spinal Instrumentation Procedure Volume and Associated Costs for Medicare Patients to 2050.

Instrumented spinal fusions can be used in the treatment of vertebral fractures, spinal instability, and scoliosis or kyphosis. Construct-level selection has notable implications on postoperative recovery, alignment, and mobility. This study sought to project future trends in the implementation rates and associated costs of single-level versus multilevel instrumentation procedures in US Medicare patients aged older than 65 years in the United States. Data were acquired from the Centers for Medicare & Medicaid Services from January 1, 2000, to December 31, 2019. Procedure costs and counts were abstracted using Current Procedural Terminology codes to identify spinal level involvement. The Prophet machine learning algorithm was used, using a Bayesian Inference framework, to generate point forecasts for 2020 to 2050 and 95% forecast intervals (FIs). Sensitivity analyses were done by comparing projections from linear, log-linear, Poisson and negative-binomial, and autoregressive integrated moving average models. Costs were adjusted for inflation using the 2019 US Bureau of Labor Statistics' Consumer Price Index. Between 2000 and 2019, the annual spinal instrumentation volume increased by 776% (from 7,342 to 64,350 cases) for single level, by 329% (from 20,319 to 87,253 cases) for two-four levels, by 1049% (from 1,218 to 14,000 cases) for five-seven levels, and by 739% (from 193 to 1,620 cases) for eight-twelve levels (P < 0.0001). The inflation-adjusted reimbursement for single-level instrumentation procedures decreased 45.6% from $1,148.15 to $788.62 between 2000 and 2019, which is markedly lower than for other prevalent orthopaedic procedures: total shoulder arthroplasty (-23.1%), total hip arthroplasty (-39.2%), and total knee arthroplasty (-42.4%). By 2050, the number of single-level spinal instrumentation procedures performed yearly is projected to be 124,061 (95% FI, 87,027 to 142,907), with associated costs of $93,900,672 (95% FI, $80,281,788 to $108,220,932). The number of single-level instrumentation procedures is projected to double by 2050, while the number of two-four level procedures will double by 2040. These projections offer a measurable basis for resource allocation and procedural distribution.

Return to Duty in Military Servicemembers After High Tibial Osteotomy Not Associated With Preoperative Radiographic Parameters : A Retrospective Analysis.

Evidence on return to sports/work after high tibial osteotomy (HTO) is limited, especially in a young, high-demand population. To (1) identify whether preoperative knee pathology or intraoperative correction was associated with successful return to duty (RTD) and (2) assess whether postoperative complications and reoperation were associated with failure to RTD. Case series; Level of Evidence, 4. We performed a retrospective cohort study of a consecutive series of patients in the Military Health System aged 18 to 55 years with medial compartment osteoarthritis who underwent HTO between 2003 and 2018. Concomitant meniscal and cartilage procedures were included, while cases with concomitant ligamentous procedures were excluded. The inclusion criteria were as follows: active-duty military status, minimum 2-year follow-up, preoperative knee radiographs, and pre- and postoperative long-leg alignment radiographs. Preoperative Kellgren-Lawrence grades and pre- and postoperative hip-knee-ankle angles were measured. The primary outcome was RTD. Failure was defined as knee-related medical separation from the military or conversion to total knee arthroplasty. The secondary outcome was reoperation. A total of 55 HTOs were performed in 50 patients who met the inclusion criteria, with a mean age of 39 years old (range, 22.8-55 years). The mean follow-up was 5 years (range, 2.1-10.7 years). Ten knees (18.2%) failed HTO (1 conversion to total knee arthroplasty, 9 medical separations), 15 additional knees (27.3%) had permanent activity restrictions, and 30 knees (54.5%) returned to duty without restrictions. Reoperation occurred in 36.4% of knees and was associated with medical separation (P = .039). Younger age was associated with medical separation (P = .003) and permanent restrictions (P = .006). Patients with a postoperative varus deformity of >5° were more likely to undergo medical separation (P = .023). In a young, high-demand population, HTO succeeded in returning 54.5% of knees to full duty without restriction despite 36.4% of knees requiring reoperation. Residual varus deformity or reoperation was associated with lower RTD rates. No association was identified between RTD and preoperative osteoarthritis grading or deformity.

Segmental Sagittal Alignment in Lumbar Spinal Fusion: A Review of Evidence-Based Evaluation of Preoperative Measurement, Surgical Planning, Intraoperative Execution, and Postoperative Evaluation.

Maintaining and restoring global and regional sagittal alignment is a well-established priority that improves patient outcomes in patients with adult spinal deformity. However, the benefit of restoring segmental (level-by-level) alignment in lumbar fusion for degenerative conditions is not widely agreed on. The purpose of this review was to summarize intraoperative techniques to achieve segmental fixation and the impact of segmental lordosis on patient-reported and surgical outcomes. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, PubMed, Embase, Cochrane, and Web of Science databases were queried for the literature reporting lumbar alignment for degenerative lumbar spinal pathology. Reports were assessed for data regarding the impact of intraoperative surgical factors on postoperative segmental sagittal alignment and patient-reported outcome measures. Included studies were further categorized into groups related to patient positioning, fusion and fixation, and interbody device (technique, material, angle, and augmentation). A total of 885 studies were screened, of which 43 met inclusion criteria examining segmental rather than regional or global alignment. Of these, 3 examined patient positioning, 8 examined fusion and fixation, 3 examined case parameters, 26 examined or compared different interbody fusion techniques, 5 examined postoperative patient-reported outcomes, and 3 examined the occurrence of adjacent segment disease. The data support a link between segmental alignment and patient positioning, surgical technique, and adjacent segment disease but have insufficient evidence to support a relationship with patient-reported outcomes, cage subsidence, or pseudoarthrosis. This review explores segmental correction's impact on short-segment lumbar fusion outcomes, finding the extent of correction to depend on patient positioning and choice of interbody cage. Notably, inadequate restoration of lumbar lordosis is associated with adjacent segment degeneration. Nevertheless, conclusive evidence linking segmental alignment to patient-reported outcomes, cage subsidence, or pseudoarthrosis remains limited, underscoring the need for future research.

Enhancing robotic precision in medial UKA: Image-based robot-assisted system had higher accuracy in implant positioning than imageless robot-assisted system across 292 knees.

The objective of this study was to compare the degree of accuracy in implant positioning and limb alignment offered by two robot-assisted (RA) systems: an image-based robot-assisted (IBRA) versus an imageless robot-assisted (ILRA) system for the treatment of medial knee osteoarthritis with unicompartmental knee arthroplasty (UKA). This retrospective radiographic study included medial UKAs performed between 2011 and 2023. Radiographic measurements taken preoperatively and at 1-year postoperative control visit focusing on hip-knee-ankle angle (HKA), posterior tibial slope (PTS), tibial component coronal alignment relative to Cartier's angle and restoration of proper joint line (JL) height were analyzed. Outliers for postoperative measurements were defined as follows: HKA <175° or >180°, PTS <2° or >8°, >3° or <-3° alterations in Cartier's angle and ±2 mm changes in the height of the joint line. The final sample consisted of 292 medial UKAs: 95 (32.5%) with an IBRA system and 197 (67.5%) with an ILRA system. Implant positioning and limb alignment were more accurate in the group of patients treated with IBRA, HKA (77.9% vs. 67.5%, p = 0.07), PTS (93.7% vs. 82.7%, p = 0.01), restoration of tibial varus relative to Cartier's angle (87.4% vs. 65%, p < 0.001) and restoration of JL height (81.1% vs. 69.5%, p = 0.04). Medial UKA surgery using an IBRA system was associated with a higher degree of accuracy in implant positioning and postoperative limb alignment as compared to an ILRA system. This is a valuable contribution to help communicate the advantages of using this surgical technique and improve its reproducibility. Level III, Retrospective cohort study.

Hip Osteoarthritis in Patients Undergoing Surgery for Severe Adult Spinal Deformity: Prevalence and Impact on Spine Surgery Outcomes.

Hip osteoarthritis (OA) is common in patients with adult spinal deformity (ASD). Limited data exist on the prevalence of hip OA in patients with ASD, or on its impact on baseline and postoperative alignment and patient-reported outcome measures (PROMs). Therefore, this paper will assess the prevalence and impact of hip OA on alignment and PROMs. Patients with ASD who underwent L1-pelvis or longer fusions were included. Two independent reviewers graded hip OA with the Kellgren-Lawrence (KL) classification and stratified it by severity into non-severe (KL grade 1 or 2) and severe (KL grade 3 or 4). Radiographic parameters and PROMs were compared among 3 patient groups: Hip-Spine (hip KL grade 3 or 4 bilaterally), Unilateral (UL)-Hip (hip KL grade 3 or 4 unilaterally), or Spine (hip KL grade 1 or 2 bilaterally). Of 520 patients with ASD who met inclusion criteria for an OA prevalence analysis, 34% (177 of 520) had severe bilateral hip OA and unilateral or bilateral hip arthroplasty had been performed in 8.7% (45 of 520). A subset of 165 patients had all data components and were examined: 68 Hip-Spine, 32 UL-Hip, and 65 Spine. Hip-Spine patients were older (67.9 ± 9.5 years, versus 59.6 ± 10.1 years for Spine and 65.8 ± 7.5 years for UL-Hip; p < 0.001) and had a higher frailty index (4.3 ± 2.6, versus 2.7 ± 2.0 for UL-Hip and 2.9 ± 2.0 for Spine; p < 0.001). At 1 year, the groups had similar lumbar lordosis, yet the Hip-Spine patients had a worse sagittal vertebral axis (SVA) measurement (45.9 ± 45.5 mm, versus 25.1 ± 37.1 mm for UL-Hip and 19.0 ± 39.3 mm for Spine; p = 0.001). Hip-Spine patients also had worse Veterans RAND-12 Physical Component Summary scores at baseline (25.7 ± 9.3, versus 28.7 ± 9.8 for UL-Hip and 31.3 ± 10.5 for Spine; p = 0.005) and 1 year postoperatively (34.5 ± 11.4, versus 40.3 ± 10.4 for UL-Hip and 40.1 ± 10.9 for Spine; p = 0.006). This study of operatively treated ASD revealed that 1 in 3 patients had severe hip OA bilaterally. Such patients with severe bilateral hip OA had worse baseline SVA and PROMs that persisted 1 year following ASD surgery, despite correction of lordosis. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.