Full-length Radiographs Research Articles

Varus tibial alignment is associated with greater tibial baseplate migration at 10 years following total knee arthroplasty

To examine implant migration and articular behavior of primary total knee arthroplasty (TKA) at 10years after index surgery and correlate to implant alignment. Thirty-five patients underwent a cemented posterior stabilized total knee arthroplasty with a surgical objective of neutral alignment and were enrolled in a long-term radiostereometric analysis (RSA) study. At 10years after surgery, patients were analyzed for implant migration using RSA as well as radiographic assessment of articular behavior at four positions of knee flexion. Implant position and alignment was measured on full-length radiographs. Patient demographics and reported outcomes were also collected. No difference between patient demographics or patient-reported outcomes were found. When categorized into neutral and varus groupings, no difference in migration was present. If alignment was considered as a continuous variable, there was no correlation between overall leg alignment and migration, however, migration increased with an increasing varus tibial alignment. Although contact location did not differ between neutral and varus groups through a range of motion, condylar liftoff was much more common in the varus group, of which all were lateral liftoff. Increased tibial varus results in increased implant migration. Overall varus limb alignment is correlated with isolated lateral compartment liftoff, and liftoff occurs more commonly than in neutral aligned knees. The increased migration and liftoff raise concerns about the longevity of malaligned total knee replacements. If a goal of overall varus limb alignment is desired for TKA, the tibia should remain neutral. Level III.

Radiographic Assessment of Lower-Limb Discrepancy

This study compares different lower-limb length measurements using tests of lower-limb upright full-length radiography and anteroposterior radiography of load-bearing hips. Forty-seven consecutive individuals aged 17 to 61 years (mean ± SD, 31.47 ± 11.42 years) voluntarily took part in the study; 23 (48.9%) were women and 24 (51.1%) were men. All individuals presenting a difference of 5 mm or greater between both lower limbs quantified with a tape measure were included. All of the participants signed an informed consent form to take part in the study. Two anteroposterior load-bearing radiographs were taken: one of the hip and an upright full-length radiograph of the lower limbs. Lower-limb-length discrepancy was quantified by taking different reference points. Interobserver and intraobserver reliability was assessed for each radiographic measurement. Any correlation between the different measurements were also verified. Interobserver and intraobserver reliability was high for all of the measurements because the intraclass correlation was greater than 0.75 in all of the cases. There was a strong and positive correlation between the different measurements because when performing bivariate correlations with the Pearson correlation coefficient, positive values close to 1 were found. In this study, the different reference points reported in the upright full-length radiograph in addition to the hip radiographs are useful for assessing lower-limb-length discrepancy. The results showed that there is a correct correlation between the different measurements.

Measurement of lower limb alignment: there are within-person differences between weight-bearing and non-weight-bearing measurement modalities

Purpose Previous studies have compared weight-bearing mechanical leg axis (MLA) measurements to non-weight-bearing measurement modalities. Most of these studies compared mean or median values and did not analyse within-person differences between measurements. This study evaluates the within-person agreement of MLA measurements between weight-bearing full-length radiographs (FLR) and non-weight-bearing measurement modalities (computer-assisted surgery (CAS) navigation or MRI).Materials and methodsTwo independent observers measured the MLA on pre- and postoperative weight-bearing FLR in 168 patients. These measurements were compared to non-weight-bearing measurements obtained by CAS navigation or MRI. Absolute differences in individual subjects were calculated to determine the agreement between measurement modalities. Linear regression was used to evaluate the possibility that other independent variables impact the differences in measurements.ResultsA difference was found in preoperative measurements between FLR and CAS navigation (mean of 2.5° with limit of agreement (1.96 SD) of 6.4°), as well as between FLR and MRI measurements (mean of 2.4° with limit of agreement (1.96 SD) of 6.9°). Postoperatively, the mean difference between MLA measured on FLR compared to CAS navigation was 1.5° (limit of agreement (1.96 SD) of 4.6°). Linear regression analysis showed that weight-bearing MLA measurements vary significantly from non-weight-bearing MLA measurements. Differences were more severe in patients with mediolateral instability (p = 0.010), age (p = 0.049) and ≥3° varus or valgus alignment (p = 0.008).ConclusionThe clinical importance of this study lies in the finding that there are within-person differences between weight-bearing and non-weight-bearing measurement modalities. This has implications for preoperative planning, performing total knee arthroplasty (TKA), and clinical follow-up after TKA surgery using CAS navigation or patient-specific instrumentation.Level of evidenceIII.

The Effect of Sagittal Knee Deformity on Preoperative Measurement of Coronal Mechanical Alignment during Total Knee Arthroplasty.

PurposeThe purpose of this prospective study was to determine correlation between coronal mechanical alignment measured on preoperative standing full-length radiographs and navigation during total knee arthroplasty (TKA) in the presence of an associated sagittal deformity (hyperextension and flexion deformity).Materials and MethodsCoronal mechanical alignment measured on preoperative, standing, full-length, hip-to-ankle anteroposterior radiographs was compared with intraoperative measurements recorded with computer navigation in 200 primary navigated TKAs.ResultsThe mean difference in mechanical alignment between the two techniques was significantly greater (p=0.001) in patients with an associated flexion deformity >10° when compared to knees with associated flexion deformity ≤10°; 48% of knees with a flexion deformity >10° had a difference of ≥3° between the full-length radiograph and navigation alignment measurements. There was a strong correlation between the radiographic and navigation measurement techniques.ConclusionsThe mean difference in coronal mechanical alignment between the two techniques was significantly higher in patients with an associated flexion deformity >10°. Hence, surgeons should take caution when relying on preoperative full-length radiographs for determining coronal mechanical alignment in patients with an associated flexion deformity >10° where using navigation may be more reliable.

Cervical kyphosis in patients with Lenke type 1 adolescent idiopathic scoliosis: the prediction of thoracic inlet angle

BackgroundSeveral studies have explored cervical kyphosis (CK) in adolescent idiopathic scoliosis (AIS) patients. However, few studies have evaluated the cervical alignment in these patients according to their coronal curve type. The aim of this study was to analyze the radiological features of cervical sagittal alignment in Lenke 1 AIS patients before and after surgery.MethodsThis is a retrospective study enrolled 50 patients. Preoperative and postoperative standing full-length radiographs (at last follow-up after operation) were used to measure the coronal and sagittal parameters. Main sagittal parameters included C2–C7 angle, thoracic inlet angle (TIA), T1 slope, proximal thoracic kyphosis (PTK, T1-5 kyphosis) and thoracic kyphosis (TK, T5-12 kyphosis).ResultsThe TIA of patients with CK was significantly smaller than that of patients with CL (63.0° vs. 76.3°, p < 0.05) and the cutoff value was 71°. The TIA of patients with CK after surgery was significantly smaller than that of patients with CL postoperatively (62.5° vs. 74.6°, p < 0.05) and the cutoff value was 62°. In patients with postoperative CL, there was a significant increase in their PTK and a reduction in their TK, regardless of preoperative CL or CK. In patients whose CL deteriorated to CK after surgery, both their PTK and TK significantly decreased after surgery.ConclusionsPatients with TIA less than 71° were more likely to have CK. And patients with TIA less than 62° would lead to the postoperative uncorrected or new onset of CK. The increased PTK after operation could have a beneficial effect on the improvement of CL.

Comparison of a Newer Versus Older Protocol for Circumferential Minimally Invasive Surgical (CMIS) Correction of Adult Spinal Deformity (ASD)—Evolution Over a 10-Year Experience

Study DesignRetrospective. ObjectivesCompare circumferential minimally invasive surgical (CMIS) correction outcomes of patients treated for adult spinal deformity (ASD) with a newer versus older protocol Summary of Background DataCMIS techniques have become increasingly popular. Increasing experience and learning curve may help improve outcomes. MethodsA prospectively collected database was queried for all patients who underwent CMIS correction of ASD (Cobb angle >20° or sagittal vertical axis [SVA] >50 mm or pelvic incidence–lumbar lordosis mismatch >10) at 3+ levels. Those without a full-length radiograph or 2-year follow-up were excluded. Patients were compared based on treatment using our original or newer protocol. ResultsThe original protocol had 76 patients with an average age of 66.99 years (range 46–81, standard deviation [SD] 9.03), and the new protocol had 53 patients with average age of 65.85 years (range 48–85, SD 8.08). Preoperative and latest visual analog scale (VAS) scores in the original were 6.85 and 3.45 (p = .001) and in the new were 6.19 and 2.27 (p = .004). Delta-VAS scores were 3.27 and 4.27. The Oswestry disability index (ODI) reduced from 45.84 to 32.91 (p = .041) in the original and from 44.21 to 25.39 (p = .017) in the new. Average delta-ODIs were 22.25 and 24.01. Preoperative, latest, and delta-SF physical component scores for the original were 35.38, 42.42, and 10.06 and for the new, 30.89, 39.49, and 11.93. SF mental component scores were 50.96, 55.19, and 12.84 and 50.12, 52.99, and 8.85. The original and new protocols had latest Cobb angles of 11.54° and 11.12° (p = .789), delta-Cobb angles of 14.51° and 20.03° (p < .05), latest SVAs of 42.85 and 30.58 mm (p < .05) and latest PI–LL mismatch of 15.49 and 9.00 mm (p < .05). In the original and the new, the average preoperative SVAs that reliably achieved a postoperative SVA of 50 mm or less were 84 and 119 mm, respectively, and the maximum delta-SVAs were 89 and 120 mm. The new protocol had fewer surgical complications (p < .05). ConclusionImprovements in radiographic scores, functional outcomes, and limits of SVA correction and lower complication rates suggest that the new protocol may help improve outcomes. These findings may be a reflection of our 10-year experience and advances in the learning curve. Level of EvidenceLevel IV.

No impact of under-correction and joint line obliquity on clinical outcomes of total knee arthroplasty for the varus knee.

It has been hypothesized that under-correction of a preoperative varus deformity may be more natural and improve outcomes after total knee arthroplasty (TKA). This study's purpose was to assess the impact of hip-knee-ankle (HKA) alignment and joint line obliquity on TKA outcomes for the varus knee. All patients with a preoperative varus deformity received both preoperative and postoperative standing, full-length radiographs from which two independent observers performed radiographic measurements including the HKA axis and mechanical medial proximal tibial angle (mMPTA). Patients were categorized based on their HKA into neutral (0° ± 3°), mild varus (-6° to -3°), severe varus (≤ -6°), and valgus (>3°) cohorts, and separately categorized based on their mMPTA into neutral (90° ± 2°), mild varus (86°-88°), severe varus (<86°), and valgus (>92°) cohorts. Two hundred and fifty-six patients (mean age 63.8 ± 9.0 years, BMI 33.0 ± 6.2kg/m2, follow-up 1.3 ± 0.6 years) were included. There was no difference in the postoperative SF-12 physical component, mental component, Oxford knee, Forgotten Joint Score, or incremental improvement in scores based on the postoperative alignment category for either the HKA or mMPTA. There was no correlation between the magnitude of change in HKA (r = 0.03-0.1) and mMPTA (r = 0.02-0.1) from preoperatively to postoperatively with clinical outcomes. In patients undergoing TKA for a preoperative varus deformity, a specific postoperative HKA or mMPTA alignment category was not associated with improved outcomes. Therefore, categorization of optimal postoperative alignment after TKA may not be possible as static, coronal alignment is just one of many variables that can impact clinical outcomes. Future investigations focusing on the combination of static images with dynamic examinations and ligamentous balancing may shed further insight into the controversy and importance of coronal alignment following TKA. III.

Do additional full-length radiographs of the humerus and forearm improve the decision making in children with supracondylar humerus fractures?

We sought to determine the diagnostic utility of additional full-length radiographs of the forearm and humerus for pediatric supracondylar humerus fractures. A pediatric orthopedic surgeon and a senior orthopedic resident individually reviewed the initial humerus, forearm, and elbow radiographs of 55 children with a supracondylar humerus fracture and recommended definitive treatment (operative vs. nonoperative) on the basis of the modified Gartland classification. Interobserver agreements for classification and the recommended treatment were highest for the elbow radiographs (weighted κ=0.92). All disagreements in the recommended treatment were in fractures classified as Gartland type I versus II fractures. Although two children (4%) had an ipsilateral distal forearm fracture, selective versus routine use of additional full-length radiographs in children with a supracondylar humerus fracture needs to be evaluated further.

Is There a Reliable Method to Predict the Limb Length Discrepancy after Chemotherapy and Limb Salvage Surgery in Children with Osteosarcoma?

Background:For a child with osteosarcoma, prediction of the limb length discrepancy at maturity is important when planning for limb salvage surgery. The purpose of this study was to provide a reliable prediction method.Methods:A retrospective review of Chinese children receiving chemotherapy for osteosarcoma before skeletal maturity was conducted. Standing full-length radiographs of the lower extremity were used for length measurements. Length-for-age curves were constructed using the LMS method. The lower limb multiplier for a specific age and gender was calculated using the formula M = Lm/L, where M was the gender- and age-specific multiplier, Lm was the bone length at maturity, and L was the age-specific bone length. Prematurity and postmaturity radiographs were used to assess the accuracy of the prediction methods.Results:A total of 513 radiographs of 131 boys and 314 radiographs of 86 girls were used to calculate the coefficients of the multiplier. The multipliers of 8-, 9-, 10-, 11-, 12-, 13-, 14-, 15-, 16-, 17-, and 18-year-old boys after chemotherapy for osteosarcoma were 1.394, 1.306, 1.231, 1.170, 1.119, 1.071, 1.032, 1.010, 1.004, 1.001, and 1.000, respectively; while for girls at the same ages, the multipliers were 1.311, 1.221, 1.146, 1.092, 1.049, 1.021, 1.006, 1.001, 1.000, 1.000, and 1.000, respectively. Prematurity and postmaturity femoral and tibial lengths of 21 patients were used to assess the prediction accuracy. The mean prediction error was 0 cm, 0.8 cm, and 1.6 cm for the multiplier method using our coefficients, Paley's coefficients, and Anderson's method, respectively.Conclusions:Our coefficients for the multiplier method are reliable in predicting lower limb length growth of Chinese children with osteosarcoma.

Dynamic global sagittal alignment evaluated by three-dimensional gait analysis in patients with degenerative lumbar kyphoscoliosis.

Sagittal vertical axis (SVA) is the most commonly used parameter for evaluating global sagittal alignment (GSA) in a static condition. However, its dynamic statuses remain unclear. The aim of this study was to evaluate dynamic GSA of degenerative lumbar kyphoscoliosis (DLKS) using three-dimensional motion analysis system (3D-MAS). Twenty-six patients with DLKS underwent gait analysis using 3D-MAS. Static (S-) and dynamic (D-) trunk angle (TA) (the angle between the vertical axis and the line connecting C7 and S1 spinous processes) and S-sagittal trunk shift (STS) and D-STS (the distance between the two vertical lines running through C7 and S1 spinous process) were recorded during treadmill walking. Pelvic angle (PA) (the angle between the horizontal axis and the line connecting the posterior and anterior superior iliac spine) were also recorded. S-PA and D-PA represent retroversion or anteversion of the pelvis, which can be substituted for pelvic tilt. As to dynamic parameters, those at the initial five steps (Di) and the final five steps (Df) of treadmill walking were also recorded. The median S-TA, S-STS, and S-PA were 16.0°, 11.9cm, and -5.5° (retroversion). The median D parameters were Di-TA/Df-TA 21.8°/26.9°; Di-STS/Df-STS 14.1/21.1cm; and Di-PA/Df-PA 15.7°/22.8° (anteversion). All D parameters were significantly greater than S parameters (P<0.01) and all Df parameters were also significantly worse than Di parameters (P<0.001). Thus, compensated GSA by pelvic retroversion in static condition was lost due to anteversion change of the pelvis immediately after start of walking and worsened over time. Dynamic GSA assessment using 3D-MAS can avoid underestimation of GSA loss that is detected by static standing full-length radiography.

Clinical Results and Complications of Lower Limb Lengthening for Fibular Hemimelia: A Report of Eight Cases.

Fibular hemimelia is a rare but the most common congenital long bone deficiency, encompassing a broad range of anomalies from isolated fibular hypoplasia up to substantial femoral and tibial shortening with ankle deformity and foot deficiency. Most cases of fibular hemimelia manifest clinically significant leg length discrepancy (LLD) with time that requires adequate correction by bone lengthening for stable walking. Bone lengthening procedures, especially those for pathological bones, are sometimes associated with severe complications, such as delayed consolidation, fractures, and deformities of the lengthened bones, leading to prolonged healing time and residual LLD at skeletal maturity. The purpose of this study was to review our clinical results of lower limb lengthening for fibular hemimelia.This study included 8 Japanese patients who diagnosed with fibular hemimelia from physical and radiological findings characteristic of fibular hemimelia and underwent single or staged femoral and/or tibial lengthening during growth or after skeletal maturity. LLD, state of the lengthened callus, and bone alignment were evaluated with full-length radiographs of the lower limb. Previous interventions, associated congenital anomalies, regenerate fractures were recorded with reference to medical charts and confirmed on appropriate radiographs. Successful lengthening was defined as the healing index <50 days/cm without regenerate fractures.A significant difference was observed in age at surgery between successful and unsuccessful lengthening. The incidence of regenerate fractures was significantly correlated with callus maturity before frame removal. LLD was corrected within 11 mm, whereas mechanical axis deviated laterally.Particular attention should be paid to the status of callus maturation and the mechanical axis deviation during the treatment period in fibular hemimelia.

The relationship between constitutional alignment and varus osteoarthritis of the knee.

The role of neutral alignment in total knee arthroplasty (TKA) on short- and long-term outcomes has become controversial. Based on the concept of constitutional varus, it has been suggested that under-correction in TKA in a varus osteoarthritis (OA) population might lead to better clinical outcomes. However, it is still unknown what the relationship between constitutional varus and the development of end-stage OA is. The goal of this study was to analyse the contribution of constitutional varus in a medial OA population and to define a correlation between the constitutional alignment and end-stage varus OA. Based on full-length radiographs, corrected for the intra-articular deformity of the knee, of 315 patients with unilateral end-stage medial OA of the knee (Charnley type A), a correlation in the coronal plane was made between medial end-stage OA and the contralateral non-arthritic side. With increasing varus alignment in the arthritic limb, the physiologic limb alignment also became more varus. The proportion of constitutional varus rose with increasing overall alignment and was found to be continuous for males. Constitutional varus was three times higher in men when the overall arthritic alignment was greater more than 6° varus. Constitutional varus significantly contributes to varus osteoarthritis and was found to be higher than in the general population. III.

Radiological analysis of upper lumbar disc herniation and spinopelvic sagittal alignment.

A retrospective cross-sectional study was designed to explore the role of spinopelvic sagittal alignment in upper lumbar disc herniation (ULD) development. A total of 207 consecutive patients who underwent surgery for single-level lumbar disc herniation [24 with ULD and 183 with lower lumbar disc herniation (LLD)] and 40 asymptomatic volunteers were enrolled. Full-length radiographs of the spine were taken to evaluate pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), thoracic kyphosis (TK), lumbar lordosis (LL), and sagittal vertical axis (SVA). The Roussouly classification was utilized to categorize all subjects according to their sagittal alignment. Spinopelvic parameters and Roussouly classification results were compared between groups. There were significant differences in PI, SS, PT, LL, and SVA between the ULD, LLD, and control groups. PI in the ULD (40.9°) was significantly lower than in the LLD and control groups (48.8° and 47.6°, respectively). LL was significantly lower in the ULD than in the LLD (-32.4° and -40°, respectively). There were significant differences between the three groups in Roussouly types. The LLD had a significantly higher proportion (62.6%) of type 2 lordosis (flat back), and the ULD had a higher proportion (33.3%) of type 1 lordosis than the other groups. This study demonstrated the importance of PI and lumbar curvature in the pathogenesis of ULD. The higher prevalence of short LL and long TK with low PI in the ULD group implies that an increased mechanical stress at this level may be one of the risk factors of ULD.

Patient-Specific Cutting Guides Were Not Better Than Conventional Instrumentation for Total Knee Arthroplasty.

Abane L, Anract P, Boisgard S, Descamps S, Courpied JP, Hamadouche M. A comparison of patient-specific and conventional instrumentation for total knee arthroplasty: a multicentre randomised controlled trial. Bone Joint J. 2015 Jan;97-B(1):56-63. ### Question: In patients having total knee arthroplasty, are better results achieved using patient-specific cutting guides (PSCG) compared with conventional instrumentation? ### Design: Randomized (allocation concealed), blinded (outcome assessor), controlled trial with 3 months of follow-up. ### Setting: 2 tertiary care centers in France. ### Patients: 140 patients between 18 and 85 years of age (mean age, 69 years; 63% women) with 140 knees requiring total knee arthroplasty because of primary or secondary osteoarthritis were enrolled. Exclusion criteria were active or suspected infection, tumor around the knee, previous total knee arthroplasty, the presence of hardware that could cause artifacts on magnetic resonance imaging (MRI), contraindication to MRI, the presence of deformity that required osteotomy around the knee or total knee arthroplasty, or social circumstances that could impair follow-up. 126 patients (90%) completed follow-up. ### Intervention: Patients were allocated to PSCG (n = 70) or conventional instrumentation (n = 70). Patients in the PSCG group were evaluated with MRI and standing full-length radiographs six weeks before surgery. A preliminary surgical plan, including the level of resection and the alignment and size of the femoral and tibial components, was formulated from the images according to the preference …

The Inadequacy of Short Knee Radiographs in Evaluating Coronal Alignment After Total Knee Arthroplasty

BackgroundPrior studies have associated coronal alignment after total knee arthroplasty (TKA) with implant survivorship. Results have been based on either the femorotibial angle (FTA) on a short knee film or the hip-knee-ankle angle (HKA) on a full-length radiograph. The purpose of this study was to determine if the FTA on short knee radiographs can accurately predict the true HKA alignment after TKA. MethodsTwo orthopedic surgeons measured the FTA, HKA, medial proximal tibial angle, and lateral distal femoral angle in 262 patients who had both short and full-length standing radiographs before and/or after primary TKA. Overall coronal alignment was considered neutral if the FTA was between 2.4° and 7.2° on short knee x-rays or if the HKA was between −3° and 3° on full-length films. ResultsPreoperatively, 13.9% (26/187) of knees had a neutral FTA on short films, but 50% (13/26) of those were in varus or valgus on full-length films. Postoperatively, 51.4% (106/206) of knees had a neutral FTA on short films, but 27.4% (29/106) of those knees were in varus or valgus on full-length films. When comparing alignment classifications (neutral, varus, or valgus) based on the short vs full-length images, 13.9% (26/187) of patients had discordant classifications on preoperative imaging, and 33.0% (68/206) had discordant classifications on postoperative imaging. ConclusionA significant proportion of patients were misclassified as varus, valgus, or neutral based on the FTA when compared to the HKA. Short knee x-rays serve as an inaccurate proxy for full-length films when assessing coronal alignment after TKA.

Pelvic Reference Selection in Patients with Unilateral Crowe Type IV DDH for Measuring Leg Length Inequality

We identified the presence of deformities in the affected pelvis of unilateral Crowe type IV DDH patients, and if present, whether the teardrop and ischial lines were parallel with the sacral base line. We also verified whether the sacral base line provided a better pelvic landmark than the teardrop line for determining leg length inequality (LLI). After leveling the pelvis by using a block to lift the short leg, standard anterior-posterior full-length radiography was performed on 10 patients and 10 healthy volunteers as controls. The ratio of pelvic heights on each side of the pelvis, the angles formed by the sacral base line and the other 2 lines between 2 groups were measured. LLI were measured by sacral base line and teardrop line respectively. The ratio between the pelvic heights was lower in the patient group than in the control group (0.95 versus 0.99). The angles between the teardrop and ischial lines and the sacral base line in the patient group were both greater than in the control group (6.08° versus 0.92° and 7.13° versus 0.97°). LLI measured from the sacral base line was larger than from the teardrop line in the patient group (5.55 cm versus 4.36 cm). There was pelvic asymmetry and the sacral base line was not parallel with the other 2 lines in unilateral Crowe type IV DDH. The leveled sacral base line was perpendicular to the longitudinal axis of the body, and may be a better choice for accurate LLI measurement in this situation.

Correlation between pelvic tilt and the sacro-femoral-pubic angle in patients with adolescent idiopathic scoliosis, patients with congenital scoliosis, and healthy individuals.

To examine whether the sacro-femoral-pubic (SFP) angle could estimate pelvic tilt (PT) in scoliotic and normal subjects. One hundred nine subjects including 38 patients with adolescent idiopathic scoliosis (AIS), 35 patients with congenital scoliosis (CS), and 36 healthy individuals were studied. PT, as the angle between the lines connecting the midpoint of the sacral plate to the centroid of one acetabulum and the vertical plane, and the SFP angle, as the angle between the midpoint of the upper sacral endplate, the centroid of one acetabulum, and the upper midpoint of the pubic symphysis, were calculated on full-length lateral and anteroposterior radiographs, respectively. Correlations between PT and the SFP angle were investigated in each group. The three groups were comparable in terms of age, sex, and the mean SFP angle. The mean PT, however, was significantly lower in healthy subjects compared to that in patients with AIS and CS. Significant and reverse correlations were present between PT and the SFP angle in all three groups (AIS: r = -0.32, p = 0.04, PT = 82.5 - average SFP angle; CS: r = -0.48, p = 0.003, PT = 95.41 - average SFP angle; healthy: r = -0.33, p = 0.04, PT = 88.95 - average SFP angle). Unlike two previous reports, the SFP angle correlated poorly to PT in this study, limiting its use as a suitable surrogate for PT in scoliotic and healthy subjects.

Postoperative cervical deformity in 215 thoracolumbar patients with adult spinal deformity: prevalence, risk factors, and impact on patient-reported outcome and satisfaction at 2-year follow-up.

Retrospective review of prospective multicenter database. Quantify the incidence of new onset cervical deformity (CD) after adult spinal deformity surgery of the thoracolumbar spine, identify predictors of development, and determine the impact on outcomes. High prevalence of residual CD has been identified after surgical treatment of adult spinal deformity. Development of new onset CD is less understood and its clinical impact unclear. A total of 215 patients with complete 2-year follow-up and full-length radiographs met inclusion criteria. CD was defined by T1 slope minus Cervical Lordosis (CL) more than 20°, C2-C7 sagittal vertical axis more than 40 mm, or C2-C7 kyphosis more than 10°. Univariate analysis was performed using t tests or tests of proportion. Multivariate logistic regression was used to determine independent predictors of new onset CD. The impact of CD on health-related quality of life and satisfaction was measured using repeated measures mixed models or logistic regression as appropriate, accounting for potential confounders. The overall rate of CD at 2 years after surgery was 63%. Univariate analysis revealed that patients who developed new onset CD postoperatively had higher incidence of diabetes (7.35% vs. 1.28%, P = 0.05), increased preoperative C2-C7 sagittal vertical axis (P = 0.04) and C2 slope (P = 0.038), and smaller diameter rods used at surgery (P = 0.032). Independent predictors of new onset CD at 2 years included: diabetes (odds ratio, 10.49; P = 0.046) and increased preoperative T1 slope minus cervical lordosis (odds ratio, 1.08/º; P = 0.022). Ending instrumentation below T4 was a negative predictor (odds ratio, 0.31; P = 0.019). Patients with and without CD experienced improvements in 2-year 36-Item Short Form Health Survey (P = 0.0001), Oswestry Disability Index (P = 0.0001), and Scoliosis Research Society (P = 0.0001). Rates and overall improvement were similar. CD was not associated with decreased satisfaction (P = 0.28). A total of 47.7% of patients without preoperative CD developed new onset postoperative CD after thoracolumbar surgery. Independent predictors of new onset CD at 2 years included diabetes, higher preoperative T1 slope minus cervical lordosis, and ending instrumentation above T4. Significant improvements in health-related quality of life scores occurred despite the development of postoperative CD. 2.

Lung volume change after pedicle subtraction osteotomy in patients with ankylosing spondylitis with thoracolumbar kyphosis.

A retrospective clinical study. To investigate the lung volume (LV) change in patients with ankylosing spondylitis (AS) with thoracolumbar kyphosis after the pedicle subtraction osteotomy procedure. Thoracolumbar kyphosis with respiratory impairment is the consequence of most untreated AS patients. Restrictive pulmonary function is prevalent in these patients. The ideal evidence for restrictive pulmonary function impairment is to investigate the LV. A computed tomography (CT)-based method can help to obtain accurate LV change during the osteotomy. Twenty-eight patients with AS with thoracolumbar kyphosis were included. All of these patients underwent pedicle subtraction osteotomy to correct their sagittal deformity. Pre- and postoperative full-length radiographs and CT scans were reviewed. The sagittal correction of the spine was measured. CT scans were used to estimate the pre- and postoperative LV with software. The relationship between the sagittal correction and the LV change was investigated. All the patients were followed up for 2 years at least. The pedicle subtraction osteotomy procedure was performed safely on each patient without serious complications. The average preoperative T1-S1 Cobb was 67.7° (42°∼88°) and the postoperative was 7.6° (-11°∼21°). T1-S1 Cobb change was 60.0° in average (P < 0.05). The LV increased by 396 mL in average. Significant correlation was found between the percentage of LV change and T1-S1 Cobb change (r = 0.7219, P < 0.05). The location we selected for pedicle subtraction osteotomy varied from T12 to L3. No relationship was found between the osteotomy location and the LV change. The pedicle subtraction osteotomy effectively corrected the sagittal deformity of patients with AS. LV increased significantly after the osteotomy. 4.

Cervical Sagittal Measurements Strongly Correlated between Full-Length and C-Spine Radiographs

Cervical Sagittal Measurements Strongly Correlated between Full-Length and C-Spine Radiographs