A novel radiological projection of the pelvis to evaluate the sitting imbalance in pelvis nonunions and malunions

IntroductionInadequate initial management of unstable pelvic injuries is usually associated with a fracture non-union and/or mal-union. Complete clinical and imaging evaluation is mandatory for a correct preoperative planning. Among other symptoms, sitting discomfort may arise from asymmetry of the ischial tuberosities or pressure from a prominent bony projection. Conventional radiographs are usually taken with the individual in a supine position and not in position where the symptoms are referred. We attempted to define a new radiological projection different than the regular pelvis views to study the position of pelvis of a normal person in sitting position. The second objective was to demonstrate its utility in the evaluation of a pelvic deformity.Material and methodsFifteen healthy individuals were evaluated with a radiological projection in a sitting position. One patient with a vertically migrated pelvis nonunion was also evaluated with the same radiological protocol.ResultsIn each volunteer’s radiological study, a parallel line could be drawn between the sitting table and both distal aspects of the ischial tuberosities, sacral alas and superior aspect of the iliac wings. A plumb line perpendicular to the above mentioned ones could be drawn uniting the vertebras’ spinous processes. A 90⁰ line intersection confirms the absence of deformity. In the pathological case, a pseudo scoliosis of the thoracolumbar spine is detected trying to compensate the pelvis obliquity and maintain equilibrium.ConclusionsWe determined normal and pathological radiological features in the sitting imbalance of the pelvic in the anteroposterior plane of the pelvis. The study helps to understand the biomechanics and compensation of the pelvis to define surgical indications and predict post correction anatomy.     

The Effect of Functional Pelvic Tilt on the Three-Dimensional Acetabular Cup Orientation in Total Hip Arthroplasty Dislocations

BackgroundAnterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-acetabular positions. This case-control study compares changes in 3-D acetabular cup orientation during functional pelvic tilt between posterior THA dislocations vs stable THAs.MethodsStanding and sitting 3-D cup orientation was compared between fifteen posterior dislocations vs 233 prospectively followed stable THAs. 3-D cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version, and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position.ResultsThe standing cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P = .039). Compared with the controls, from standing to sitting, they showed less posterior pelvic tilt (P < .001). This led to a significant lower coronal inclination (P < .001) and sagittal ante-inclination (P < .001) in the sitting position but similar transverse version (P = .366).ConclusionsComparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. By contrast, the transverse version was not significantly different in both positions. This confirms the importance of biplanar data on functional cup orientation.Level of EvidenceDiagnostic, Level III.     

Trunk Function and Ischial Pressure Offloading in Individuals with Spinal Cord Injury

Objective: To determine if there is a relationship between trunk function and offloading of the ischial tuberosities in individuals with Spinal Cord Injury (SCI).

Design: Prospective cross-sectional evaluation.

Setting: Sub-acute rehabilitation hospital.

Participants: Fifteen non-ambulatory participants with complete or incomplete traumatic and non-traumatic SCI, American Spinal Injury Association Impairment Scale (AIS), Classification A-D.

Outcome Measures: Isometric trunk strength using a hand held dynamometer, the ability to reach using the multidirectional reach test and offloading times of the ischial tuberosities using a customized pressure mat.

Results: Participants who were able to engage in the multidirectional reach test were defined as “Reachers”, whereas individuals who were unable to engage in the multidirectional reach test were defined as “Non-Reachers”. Trunk strength was significantly higher in Reachers compared with Non-Reachers (P < 0.05). Offloading times over the left and right ischial tuberosities were lower in Non-Reachers when compared with Reachers, however the results were statistically significant only for offloading over the right ischial tuberosity (P < 0.05). There was no correlation between trunk strength and pressure offloading times for both groups.

Conclusions: Regardless of an individual's ability to engage in a reaching task, participants with spinal cord injury spent more time offloading the left ischial tuberosity compared with the right ischial tuberosity. The study highlights the need to identify factors that may contribute to offloading behavior in individuals with spinal cord injury who lack sufficient trunk strength.     

MRI visualization of the female pelvis in the plane of the tension-free vaginal tape (TVT) procedure

We evaluated the distances and angles of the major blood vessels from various pelvic structures in the plane of the tension-free vaginal tape (TVT) procedure in 19 pelvic MR imagies. The major blood vessels were the iliofemoral vessels. The mean distance of the left iliofemoral vessels from the midline was 5.7±0.4 cm, and 5.7±0.3 cm for the right vessels. The mean distance of the left sacral tuberosities from the midline was 5.5±0.4 cm, and 5.6±0.3 cm for the right vessels. The angle between the midurethra and the left iliofemoral vessels was 50.6±4.4 cm, and 49.6±4.0 cm for the right. A significant correlation was found between the distance of the right and left iliofemoral vessels from the midline and the distance of right and left sacral tuberosities from the midline (P<0.01, P<0.007). We suggest that palpation of the sacral tuberosities might indicate the location of the iliofemoral blood vessels.Abbreviations - TVT Tension-free vaginal tape - - MRI Magnetic resonance imagingEditorial Comment: The authors evaluated the distances and angles of the major pelvic blood vessels in the plane of the tension-free vaginal tape (TVT) procedure in 19 pelvic MR images. A statistically significant correlation was found between the distance of the iliofemoral vessels from the midline and the distance of the sacral tuberosities from the midline. The authors suggest that palpation of the sacral tuberosities might alert the surgeon to those patients at greater risk for iliofemoral vessel injury during the TVT procedure.The main concern with this study is that the pelvic MR images were obtained in the supine position whereas the TVT is performed in the lithotomy position, which may change the relations of pelvic blood vessels with reference to the urethra. Further studies are needed to evaluate the clinical significance of this interesting observation in reducing vascular injuries during the TVT procedure.     

Can pelvic tilting be ignored in total hip arthroplasty?

INTRODUCTION

The orientation of acetabular component is influenced by pelvic tilt, body position and individual variation in pelvic parameters. Most post-operative adverse events may be attributed to malposition of the component in the functional position. There is evidence that orientation of the pelvis changes from the supine to standing position. Authors report a case of recurrent dislocation after total hip arthroplasty due to excessive pelvic tilting.PRESENTATION OF CASE A 69-year old female with coxarthrosis had undergone total hip replacement with recurrent dislocation of the hip on bearing weight in spite of using constrained acetabular component.

DISCUSSION

Our case report substantiates the influence of pelvic tilt, incurred by a sagittal deformity of spine, on dynamic orientation of the acetabular cup which was positioned in accordance with the anatomic landmarks alone. If the reference is only bony architecture and dynamic positions of the pelvis are not taken into account, improper functional orientation of the acetabular cup can result in sitting and standing positions. These can induce instability even in anatomically appropriately oriented acetabular component.

CONCLUSION

The sagittal position of pelvis is a key factor in impingement and dislocation after total hip arthroplasty. Pelvic tilting affects the position of acetabular component in the sagittal plane of the body as compared with its anatomic position in the pelvis. We suggest a preoperative lateral view of spine-pelvis, in upright and supine position for evaluation of a corrective adaptation of the acetabular cup accordingly with pelvic balance.     

Weight distribution in the sitting position in patients with paralytic scoliosis: pre- and postoperative evaluation

Patients with paralytic scoliosis spend most of their time in the sitting position. The spinal deformity, pelvic obliquity and uneven weight distribution on the seating surface necessitates frequent seating adaptations in the wheelchair. In this prospective study, 45 wheelchair-bound patients were evaluated preoperatively and 43 postoperatively. The pre- and postoperative evaluation was done by an independent observer. Surgical correction was performed between 1993 and 1996. Assessments included sitting balance on a box; number of seating supports in the wheelchair; weight distribution on the seating surface, measured with a computerized EMED system; Cobb angle; hip dislocation; mediolateral translation of T1 and of the apex vertebra with reference to a perpendicular line drawn upwards from the spinal process of S1; and pelvic obliquity from a line drawn between the most proximal points in the iliac crests. X-rays for the measurement of Cobb angle and pelvic obliquity were performed in sitting position. Reference values for normal weight distribution on the seating surface were obtained for 27 normal subjects and revealed a mean value of 59% of weight supported on one side. A stepwise regression analysis on the preoperative results showed that pelvic obliquity and thoracolumbar/lumbar spinal imbalance explained weight distribution on the seating surface (R(2)=0.45). There were significant improvements in all variables except in sitting balance and imbalance of T1, 1 year postoperatively. When dividing the material into two subgroups, the results showed no significant difference in any of the assessed parameters of the scoliosis, pelvic obliquity, or sitting position between individuals with even (50-59% on one side) and those with uneven (60-100% on one side) weight distribution postoperatively. The results of the assessment showed a significant improvement after surgical correction, but the majority still had pelvic obliquity and uneven weight distribution in a sitting position. The weight distribution on the seating surface preoperatively was explained by thoracolumbar/lumbar spinal imbalance and pelvic obliquity, with R(2)= 0.45. There were no significant differences in any variables in comparisons between individuals with even weight distribution and those with uneven weight distribution. For the group with even weight distribution, however, the mean pelvic obliquity was 6 degrees and in the group with uneven weight distribution the mean pelvic obliquity was 12 degrees. Attention to seating surface and adjustment of seating position is needed for patients with paralytic scoliosis.     

High prevalence of acetabular retroversion in both affected and unaffected hips after Legg-Calvé-Perthes disease

Background

Acetabular retroversion is observed in hips after various pediatric hip diseases. This study sought to examine the frequency of acetabular retroversion in both affected and unaffected hips after Legg-Calvé-Perthes disease and its correlation with the prominence of the ischial spine.

Methods

We retrospectively investigated the version and morphological features of the acetabulum using pelvic radiographs after Legg-Calvé-Perthes disease (107 affected hips treated non-operatively and 72 unaffected hips from the contralateral side). The diagnosis of acetabular retroversion was made based on the presence of a positive cross-over sign on anteroposterior pelvic radiographs. The correlation between the presence of a positive cross-over sign and modified Stulberg classes, the onset age of Legg-Calvé-Perthes disease, radiographic parameters for acetabular dysplasia and the prominence of the ischial spine were examined.

Results

The prevalence of a positive cross-over sign was 49.5 % (45 of 91 hips) in affected hips and 45.8 % (33 of 72 hips) in unaffected hips. Hips with a positive cross-over sign were significantly coexistent bilaterally. The prevalence of prominence of the ischial spine in the positive cross-over sign group was 71.4 % in the affected side and 81.8 % in the unaffected side, indicating a significant correlation between the cross-over sign and the prominence of the ischial spine in both affected and unaffected hips. The positive cross-over sign did not have any correlation with the parameters for acetabular dysplasia and the onset age, however, had a significant correlation with the severity of the femoral head deformity.

Conclusions

High prevalence of acetabular retroversion in both affected and unaffected hips after Legg-Calvé-Perthes disease was demonstrated. Symmetric acetabular deformity and the coexistence of prominence of the ischial spine suggested the effects of the Legg-Calvé-Perthes disease lesions on the skeletal development of the whole pelvis. Further follow-up is needed to clarify the pathological significance of acetabular retroversion after Legg-Calvé-Perthes disease.     

Sagittal lumbar and pelvic alignment in the standing and sitting positions

BackgroundThe sitting position has become the most common posture in today’s workplace. In relation to this position, kinematic analysis of the lumbar spine is helpful in understanding the causes of low back pain and its prevention.MethodsIn this study, we investigated the relationship between sagittal lumbar alignment and pelvic alignment in the standing and sitting positions for 50 healthy adults. Lumbar lordotic angle (LLA), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) were measured on lateral lumbar spine standing and sitting radiographs.ResultsRegarding changes from the standing to sitting positions, averageLLA, SS, and PT were ?16.6° (?49.8 %), ?18.7° (?50.3 %), and 18.3° (284.8 %), respectively (P < 0.01). In the sitting position, lumbar lordosis was reduced and pelvic rotation became posterior.ConclusionsThis study showed that LLA decreased by approximately 50 % and PT increased by approximately 25 % in the sitting position compared with the standing position. No significant gender differences were observed for LLA, SS, and PT in the standing position. In the sitting position, however, LLA and SS were markedly larger for women.     

The Variation of the Pelvis in Unilateral Crowe Type IV Developmental Dysplasia of the Hip

ObjectiveTo investigate variation of the pelvis in unilateral Crowe type IV developmental dysplasia of the hip (DDH) and analyze the reliability of pelvic landmarks.MethodsWe retrospectively received preoperative anteroposterior pelvic radiographs for 89 adult patients with unilateral Crowe type IV DDH at our institution between September 2008 and May 2019. Forty‐eight patients without a false acetabulum was type IVA and 41 with a false acetabulum was type IVB. The heights of the ilium, acetabulum, and ischium areas in affected and unaffected sides were measured. The ratios of the three areas in entire pelvis are calculated. The discrepancies of bilateral iliac crest, inferior sacroiliac articulation, teardrop, and ischial tuberosity on the bisector of the pelvis were also measured.ResultsThe mean heights of the ilium, acetabulum, ischium areas in the affected side were 74.4, 88.6, and 37.0 mm, respectively, in type IVA group and 77.7, 83.5, and 37.8 mm, respectively, in type IVB group. The heights in the unaffected side were 82.1, 84.6, and 43.8 mm, respectively, in type IVA group and 84.6, 82.0, and 44.0 mm, respectively, in type IVB group. The ratios of the ilium, acetabulum, ischium areas in affected side of Crowe type IVA group were 0.37, 0.44, and 0.19, respectively, and the ratios in unaffected side were 0.39, 0.40, and 0.21, respectively. The ratios in affected side of Crowe type IVB group were 0.39, 0.42, and 0.19, respectively, and the ratios in unaffected side were 0.40, 0.39, and 0.21, respectively. The discrepancies of bilateral iliac crest, inferior sacroiliac articulation, teardrop, and ischial tuberosity on the line of the bisector of the pelvis in Crowe type IVA group were 5.6, 5.2, 2.0, and 7.1 mm, respectively. Those in Crowe type IVB group were 8.1, 3.5, 3.5, and 4.9 mm, respectively.ConclusionsPelvic asymmetry was a common occurrence in unilateral Crowe type IV DDH in adults. Furthermore, it should be reliable to use teardrop as pelvic landmark to balance leg length discrepancy in preoperative planning.     

Lumbar Spine Degeneration and Flatback Deformity Alter Sitting-Standing Spinopelvic Mechanics—Implications for Total Hip Arthroplasty

BackgroundSpinal degeneration and lumbar flatback deformity can decrease recruitment of protective posterior pelvic tilt when sitting, leading to anterior impingement and increased instability. We aim at analyzing regional and global spinal alignment between sitting and standing to better understand the implications of spinal degeneration and flatback deformity for hip arthroplasty.MethodsSpinopelvic parameters of patients with full-body sitting-standing stereoradiographs were assessed: lumbar lordosis (LL), spinopelvic tilt (SPT), pelvic incidence minus LL (PI-LL), sagittal vertical axis (SVA), and T1 pelvic angle (TPA). Lumbar spines were classified as normal, degenerative (disc height loss >50%, facet arthropathy, or spondylolisthesis), or flatback (degenerative criteria and PI-LL >10°). Independent t-tests and analysis of variance were used to analyze alignment differences between groups.ResultsAfter propensity matching for age, sex, and hip osteoarthritis grade, 57 patients per group were included (62 ± 11 years, 58% female). Mean standing and sitting SPT, PI-LL, SVA, and TPA increased along the spectrum of disease severity. Increasing severity of disease was associated with decreasing standing and sitting LL. The flatback group demonstrated the greatest sitting SPT, PI-LL, SVA, and TPA. The amount of sitting-to-standing change in SPT, LL, PI-LL, SVA, and TPA decreased along the spectrum of disease severity.ConclusionSpinal degeneration and lumbar flatback deformity both significantly decrease lower lumbar spine mobility and posterior SPT from standing to sitting in a stepwise fashion. The demonstrated hypomobility in flatback patients likely serves as a pathomechanism for the previously observed increased risk of dislocation in total hip arthroplasty.     

Early urinary complications of fractures of the pelvis

Summary The occurrence, relation to a particular type of fracture of the pelvis and the possible mechanism of early urinary complications were studied in 186 consecutive patients with fracture of the pelvis. Eighty-eight patients (47.3%) showed early urinary complications. These complications were minor in 73 patients (83.0%; 32.9% of all pelvic features) and major in 15 (17.0%; 8.1% of all pelvic fractures). The former comprised retention of urine in 41 patients (33.0%; 15.6% of all pelvic fractures), haematuria in 29 patients (33.0%; 15.6% of all pelvic fractures), and oliguria in three (3.4%; 1.6% of all pelvic fractures). The latter comprised rupture of the posterior urethra in nine patients (10.2%; 4.8% of all pelvic fractures), rupture of the bladder in five (5.7%; 2.7; of all pelvic fractures), and combined injury to the bladder and posterior urethra in one (1.1%; 0.5% of all pelvic fractures).These complications were common in relation to run-over and collision accidents. The common pelvic fracture encountered in these patients was the Type III and the individual pelvic fracture was that of both pubic rami on one or both sides; fractures of the acetabulum and posterior segment of the pelvis were next in frequency. On the other hand, fractures of a single ischial ramus or wing of the ilium were not commonly encountered. Fractures with intact pelvic ring were associated with only 9.1% of these complications; all were minor.     

半骨盆截肢后用废弃自体骨重建骨盆承重功能的解剖学与生物力学研究

目的 探讨对骨盆肿瘤行半骨盆截肢后,应用废弃自体骨重建坐骨结节和骨盆环以恢复骨盆承重功能的可行性.方法 带双侧下肢骨的10具骨盆标本,测量坐骨结节至正中矢状面和经骶骨耳状面中心冠状面的垂直距离、坐骨结节至同侧的骶骨耳状面和耻骨联合的距离.测量股骨髁和胫骨平台的最大径,对股骨和胫骨进行CT扫描并纵向剖开,观察骨质分布情况.根据解剖测量结果,选择4具成人尸体标本,应用电子万能试验机对完整骨盆和重建标本进行生物力学检测,比较两者在0-500 N的垂直加压下的稳定性.结果 坐骨结节至正中矢状面和经耳状面中心至冠状面的垂直距离分别为(4.52±0.48)cm和(3.31±0.57)cm.坐骨结节至同侧骶骨耳状面和耻骨联合的距离分别为(11.75±6.19)cm和(15.72±5.19)cm.股骨髁最大斜径在外后至内前方向平均为(7.93±0.44)cm,胫骨平台的最大径在冠状面上,平均为(7.19±0.61)cm.股骨髁和胫骨平台主要为松质骨,股骨髁松质骨平均纵向长度为(6.24±0.22)cm,胫骨上端平均纵向长度为(5.64±0.18)cm.在生物力学试验中,重建骨盆的抗压缩能力较完整骨盆弱,但在载荷去除后,重建骨盆和完整骨盆均可恢复原来的状态,说明重建骨盆和完整骨盆同样为弹性良好的刚体结构,具有较好的即刻稳定性.结论 半骨盆截肢后,可应用废弃股骨或胫骨重建坐骨结节和骨盆环,为患者坐立和装配假肢提供力学支持点,以降低半骨盆截肢者的残废程度.     

Technique of pudendal nerve localization for block or stimulation

A diagnostic technique is described for study of the pudendal nerve via a dorsal rather than perineal approach. The method offers unique advantages for the urodynamic study of sphincteric function. The patient is placed in the prone position with slight flexion of the hips. The position of the ischial spine is identified topographically using the ischial tuberosities, greater trochanter and lower edge of the ischial-tuberous ligament. Local anesthesia and electrical stimulation then are used to position a needle tip adjacent to the pudendal nerve. This approach allows for specific localization of the nerve for accurate temporary or permanent nerve block. It also permits continuous urodynamic monitoring of pelvic floor behavior with stimulation of the pudendal nerve to assess functional integrity of the nerve and the pelvic floor striated muscles.     

Stabilization of fatigue fractures of the dorsal pelvis with a trans-sacral bar. Operative technique and outcome

IntroductionDue to ageing of our population the number of fatigue fractures of the pelvic ring is steadily growing. These fractures are often treated with bed rest but may result in a disabling immobility with severe pain. An operative treatment is an option in these cases. The aim of operative treatment is bony healing obtained by stable fixation giving back to the patient's previous mobility. Optimal surgical treatment is currently under debate. Sacroiliac screw fixation and sacroplasty are used for stabilization of the dorsal pelvis. Due to the technique and the low density of spongious sacral bone, no or only low compression in the fracture site is obtained, which may inhibit bony healing. The trans-sacral bar compression osteosynthesis is presented as an alternative procedure. We present the outcome of 11 patients, who were treated with this method.MethodsThe patient is placed in prone position on the operation table. Under image intensifier control, a 5 mm threaded sacral bar is inserted through the body of S1 from the left to the right dorsal ilium. Nuts are placed over the bar achieving fracture compression. When anterior pelvic instability is present, an anterior osteosynthesis is also performed. Clinical and radiological outcome were evaluated one year after index surgery with different scoring systems.ResultsEleven patients (9 F and 2 M) were treated between 2005 and 2010. The mean age of the patients was 73 years at time of operation. There were no mechanical complications. Postoperatively there was a temporary nerve palsy of L5 in one case. The mean follow-up was 14 months. In all patients, a bony healing of the dorsal pelvic ring was achieved. Seven patients showed a major clinical improvement, in four patients a moderate.ConclusionsTrans-sacral bar osteosynthesis is a promising method for stabilization of fatigue fractures of the pelvic ring. Only with this method, a high interfragmentary compression is achieved, independent of the quality of the spongious bone of the sacral body.     

Changes in the global spine alignment in the sitting position in an automobile

BACKGROUND CONTEXTStudies of the changes in spine alignment in the sitting position have been limited to specific spine segments. Because there have been few studies of global spinopelvic alignment in the sitting position, it is important to assess the changes associated with this position for such settings as developing future design of seats and achieving appropriate restoration of spine alignment.PURPOSEThis study aimed to measure changes in global spine alignment when people are sitting in car seats and to analyze the characteristics of those changes.STUDY DESIGNThis was a prospective, collaborative study of the radiological evaluation of changes in global spine alignment.PATIENT SAMPLEThe study included 113 asymptomatic adult participants (56 men and 57 women) without a history of spine disease or lower limb surgery, and with no current lower back or leg pain.OUTCOME MEASURESRadiographic findings were assessed by measurement of various angles: cervical lordosis (CL), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), C7 sagittal vertical axis (C7-SVA), T1 spinopelvic inclination (T1SPI), and T1 pelvic angle (TPA).METHODSRadiographs were obtained in the standing and sitting positions. The objective variables analyzed statistically were spine alignments (CL, TK, TLK, LL, C7-SVA, T1SPI, TPA, SS, PT, and PI) measured in the standing position, body alignments (CL, TK, TLK, LL, C7-SVA, T1SPI, TPA, SS, and PT) measured in the sitting position, and stand-to-sit changes (∆CL, ∆TK, ∆TLK, ∆LL, ∆C7-SVA, ∆T1SPI, ∆TPA, ∆SS, and ∆PT). Explanatory variables were sex, age, body height, and body mass index.RESULTSChanging posture from standing to sitting decreased CL by an average of 5.3°, slightly decreased TK by an average of 1.3°, increased TLK by an average of 6.8°, decreased LL by an average of 35°, decreased SS by an average of 49.2°, increased PT by an average of 49.2°, shifted C7-SVA backward by an average of 106.7 mm, decreased T1SPI by an average of 18.8°, and increased TPA by an average of 21.1°. Statistical analysis revealed that ΔLL was significantly decreased in elderly participants. After the stand-to-sit change, ΔTLK and ∆TPA were significantly increased in taller participants and ΔT1SPI was significantly decreased in taller participants.CONCLUSIONSAmong other changes, most notably LL is decreased and the pelvic tilt is increased when a person is sitting in a car seat. However, these changes in spine alignment differ with age and height. These findings may be useful for the development of future design of seats and for achieving appropriate surgical restoration of spine alignment.     

Simultaneous progression patterns of scoliosis,pelvic obliquity,and hip subluxation/dislocation in non-ambulatory neuromuscular patients: an approach to deformity documentation

Background

A triad of deformities—thoracolumbar scoliosis, pelvic obliquity, and femoral head (hip) subluxation/dislocation—occurs frequently in non-ambulatory neuromuscular patients, but their close inter-relationship is infrequently appreciated or quantified. We propose a deformity documentation approach to assess each component simultaneously.

Methods

The documentation assesses each component for maximal functional level, deformity, and flexibility/rigidity: deformity from antero-posterior radiographs (scoliosis—maximal functional position, pelvic obliquity—sitting, hip position—supine) and flexibility/rigidity from extent of repositioning on supine (spine, pelvis) and frog lateral (hip) radiographs. The approach was applied in 211 patients: Duchenne muscular dystrophy (110), spinal muscular atrophy (49), cerebral palsy (26), and other neuromuscular disorders (26).

Results

Measurement of 2124 radiological data points allowed for deformity (mild to moderate to severe) and flexibility/rigidity (fully reducible to partially to non-reducible) gradations for scoliosis, pelvic obliquity, and hip subluxation/dislocation. The charting documented: (1) numerical deformity and flexibility/rigidity changes [x-axis: age; y-axis: angulation (scoliosis and pelvic obliquity) and percent coverage (hip subluxation or dislocation) from 0–120]; and (2) grade deformity and flexibility/rigidity changes [x-axis: age; y-axis: deformity and flexibility/rigidity, following conversion of numerical measurements to a 1–5 grade scale]. In subgroups with the most extensive documentation, thoracolumbar and lumbar scoliosis extended into the sacrum with 98 % (114/116) accompanied by pelvic obliquity; and scoliosis developed more rapidly than hip deformity in 44 % (28/63), scoliosis and hip deformity developed at the same time in 40 % (25/63), and hip deformity developed more rapidly than scoliosis in 16 % (10/63) (Pearson’s chi-squared test p = 0.0501, almost significant).

Conclusion and significance

Documentation of the triad of neuromuscular deformities is applicable to all diagnoses; it outlines maximal functional level, deformity, and flexibility/rigidity at each site; and it shows the relationship between spine, pelvic, and hip deformation. Prospective charting will enhance both clinical management and clinical research into neuromuscular deformity.     

Differential diagnosis and treatment of enchondromas and atypical cartilaginous tumours of the pelvis: analysis of 21 patients

Introduction

Studies focusing on enchondroma and atypical cartilaginous tumour (ACT) of the pelvis are lacking. The purpose of this study was to verify possible clinical and radiological findings with regard to distinguishing enchondromas from ACT of the pelvis. In addition, this study analysed functional and oncological outcomes in patients with enchondromas or ACT of the pelvis treated with curettage or resection.

Materials and methods

We retrospectively reviewed the medical records of 21 patients with confirmed enchondroma or ACT of the pelvis treated by curettage or resection from 1985 to 2018. The minimum follow-up was 18 months. The relationship between clinical and radiological factors and tumour type or local recurrence was assessed using Fisher exact test and Mann–Whitney U test.

Results

Endosteal scalloping (p = 0.039), tumour size (0.005) and age (0.006) were shown to statistically favour ACT over enchondroma; by contrast, enchondroma and ACT patients had no difference in pain frequency (p = 0.5528). All patients with enchondroma had no local recurrence; in contrast, local recurrence occurred in one patient with ACT, initially treated with resection. The patient with local recurrence had a disease progression with a higher histological grade than the original tumour. Patients treated with curettage had better functional outcomes than patients treated with resection (p = 0.001).

Discussion

Endosteal scalloping, tumour size and age could be helpful in the differential diagnosis between enchondroma and ACT of the pelvis. In addition, our study showed that ACT of the pelvis can be safely treated with curettage due to a low risk of local recurrence and better functional results compared with resection. In case of recurrence, we suggest to treat these patients with resection for the risk of disease progression.

     

Preoperative Radiographic Assessment of Limb-length Discrepancy in Total Hip Arthroplasty

Background  

Pelvic radiographs are helpful in assessing limb-length discrepancy (LLD) before and after THA but are subject to variation. Different methods are used to determine LLDs. As a pelvic reference, both ischial tuberosities and the teardrops are used, and as a femoral reference, the lesser trochanter and center of the femoral head are used.     

Treatment options in non-unions of the pelvis: A retrospective analysis of a single center experience over 12 years

BackgroundNon-unions and chronic instability of the pelvis remain rare complications after complex high velocity injuries with vertical and rotational instability of the pelvis. Treatment options are insufficiently supported by data evidence due to the rareness of this condition.Patients and methodswe conducted a single center, retrospective study of all non-unions and pelvic instabilities between 1.1.2008 and 1.1.2019, excluding fragility fractures. Patients’ characteristics, fracture patterns, procedures and outcomes with regard to developing treatment options and successful union in the follow-up were obtained.Results26 patients were included in this retrospective analysis. The mean age was 55 years (range 34–78 years). Seventy-seven percent of the patients were male. The standard procedure consisted of radical debridement of the non-union, interposition of autologous bone graft and rigid stabilization systems. Three patients were lost to follow up. In the remaining n = 23 patients (88%) consolidation of the non-union was achieved. The mean follow up was 31.3 months (range 6–144). Follow up showed that an iliolumbar fixation seems to be favorable regarding outcome and complications.DiscussionNon-union and remaining instability of the pelvic ring represent a rare complication after high grade pelvic trauma. There are only limited data regarding the incidence and the treatment regimen is based on small study populations only. Based on our findings we recommend to combine autologous bone grafts with rigid fixation systems especially for non-union of the pelvis to restore the posterior sacroiliac arch.     

Can Flexed-Seated and Single-Leg Standing Radiographs Be Useful in Preoperative Evaluation of Lumbar Mobility in Total Hip Arthroplasty?

BackgroundThe purpose of this study is to determine whether simulated radiographs in the “flexed-seated” or “step-up” positions better demonstrate a patient’s range of spinopelvic motion between standing and sitting positions than relaxed sitting and standing radiographs.MethodsAn institutional review board approved cohort of 43 patients with hip osteoarthritis whom underwent full body sitting-standing radiographs from August 2016 to December 2017 at a single institution was reviewed. Subjects underwent single-leg step-up standing and flexed-seated radiographs, and relaxed standing and sitting radiographs. Sacral slope, spinopelvic tilt (SPT), and lumbar lordosis were measured in all radiographs. Alignment parameters were compared between both sets of imaging, and the change in SPT between the imaging modalities was plotted and stratified by pre-existing lumbar pathology.ResultsThere were significant differences between the relaxed standing and step-up radiographs and the relaxed and flexed-seated radiographs for sacral slope, SPT, and lumbar lordosis (P < .002 for all), with the exception of SPT in the relaxed and step-up standing postures (P = .110). When transitioning from the standing to sitting position, the mean changes in SPT differed significantly between both sets of radiographs. Most importantly, when plotting changes in SPT between flexed and relaxed sitting postures, patients with fusions and flatback deformity trended toward greater anterior pelvic tilting, a position of greater risk of posterior dislocation.ConclusionFlexed sitting and single-leg standing imaging may emphasize the compensatory mechanisms of patients with concomitant hip and spine pathology more than relaxed imaging using our measurements. Our method may provide insight into high dislocation risk patients compared to the previously published hip measurement method.Level of EvidenceIII.