A relook at the reliability of Rockwood classification for acromioclavicular joint injuries.

BACKGROUND: Controversies for treatment of acromioclavicular joint injuries in particular type III injuries may be partially attributed to the lack of a standardized method of radiography and measurement technique. Previous studies looking at the Rockwood classification showed poor inter- and intraobserver reliability (Kappa value approximately 0.20-0.50). We hypothesized that the use of unilateral instead of bilateral acromioclavicular joint radiographs was the cause of this finding. In this article, we standardized the methodology to perform the radiograph and to measure the coracoclavicular distances. We designed the study to focus on the reliability of differentiating type III and type V injuries. METHODS: A standardized radiographic protocol for bilateral Zanca view was established in our institution. All patients who underwent this radiographic examination over a 3-year period were reviewed. Radiographs of 55 patients with significant (type III or V) injury met the inclusion criteria. For the interobserver reliability, a retrospective radiographic review was performed by 6 orthopedic surgeons and graded as either type III or V. For intraobserver reliability, a similar process was repeated by 3 observers after a period of 6 weeks. RESULTS: Going by the majority agreement of the 6 reviewers, there were 34 type III injuries and 19 type V injuries. The Fleiss kappa for interobserver reliability was calculated to be 0.624. The Cohen kappa for intraobserver reliability was calculated to be 0.696. DISCUSSION: The use of a standardized radiographic protocol-taking bilateral Zanca views on the same radiographic plate-would help eliminate a significant amount of variability and improve the reliability of classifying acromioclavicular joint injuries using the Rockwood classification, which uses a relative measure to the contralateral site as its definition criteria. Other possible sources of poor reliability may include the masking of injuries by muscle spasm, resulting in a misdiagnosis of a high-grade injury as a lower-grade one and the possible need to subclassify type III injuries. CONCLUSION: Reliability of the Rockwood classification can be improved through the use of a standardized radiographic protocol to improve the detection of vertical instability. Similar to Rockwood dividing up Tossy grade 3 injuries when he noted the differential outcome and intervention, Rockwood type III injuries would likely require further subclassification as it remains an anomalous tool with high variability. Further studies are required to understand the pathologic basis of transition of type III into type V injury.

Finite element analysis of bone and implant stresses for customized 3D-printed orthopaedic implants in fracture fixation.

3D printing allows product customisation to be cost efficient. This presents opportunity for innovation. This study investigated the effects of two modifications to the locking compression plate (LCP), an established orthopaedic implant used for fracture fixation. The first was to fill unused screw holes over the fracture site. The second was to reduce the Young's modulus by changing the microarchitecture of the LCP. Both are easily customisable with 3D printing. Finite element (FE) models of a fractured human tibia fixed with 4.5/5.0 mm LCPs were created. FE simulations were conducted to examine stress distribution within the LCPs. Next, a material sweep was performed to examine the effects of lowering the Young's modulus of the LCPs. Results showed at a knee joint loading of 3× body weight, peak stress was lowered in the modified broad LCP at 390.0 MPa compared to 565.1 MPa in the original LCP. It also showed that the Young's modulus of material could be lowered to 50 GPa before the minimum principal stresses increased exponentially. These findings suggested the modifications could lead to improved performances of fracture fixation, and therefore likely that other orthopaedic implants survivorship could also be enhanced by customisation via 3D printing. Graphical abstract.

A 10-Year Radiographic Study Comparing Anterior Versus Posterior Instrumented Spinal Fusion in Patients With Lenke Type 5 Adolescent Idiopathic Scoliosis.

MINI: This is a long-term prospective cohort study comparing the radiographic outcomes of anterior versus posterior instrumentation for Lenke 5 adolescent idiopathic scoliosis. Both approaches were comparable in terms of radiographic outcomes up to 10 years. The posterior approach is more prone to developing proximal junctional kyphosis. STUDY DESIGN: Prospective cohort study. OBJECTIVE: To compare the long-term, radiographic coronal and sagittal outcomes of these two approaches at 10-year follow-up. SUMMARY OF BACKGROUND DATA: Both anterior and posterior instrumented fusions have been found to be safe and effective treatments for Lenke 5 adolescent idiopathic scoliosis with up to 2 to 5 years of follow-up. Few studies follow patients beyond this duration. METHODS: 36 patients who underwent anterior (n = 25) or posterior instrumented spinal fusion (n = 11) for Lenke 5 adolescent idiopathic scoliosis over a 4-year period were recruited and followed for 10 years. Preoperative clinical data include patient's age and age of menarche. Operative data included instrumented levels, duration of surgery, and surgical blood loss. Postoperative data included duration of hospital stay, duration of intensive care unit stay, and complications. Pre- and postoperative radiographic data collected include coronal Cobb angles for structural thoracolumbar/lumbar curves, and sagittal angles-sagittal vertical axis, thoracic kyphosis, global lumbar angle, pelvic incidence, pelvic tilt, sacral slope, and upper and lower end vertebrae. RESULTS: Posterior surgery had a shorter operative time (P < 0.010) and hospital stay (P < 0.010). Coronal plane deformity improved by a mean of 74% in the anterior group and 71% in the posterior group. There was no significant change at 10 years in both groups (anterior P = 0.455 and posterior P = 0.325). Sagittal parameters remained unchanged. There was a higher incidence of proximal junctional kyphosis in the posterior (45%) compared to the anterior (16%) group (P < 0.010). CONCLUSION: Both anterior and posterior instrumentation and fusion are successful surgeries after 10 years of follow-up. They are comparable with regards to their ability to achieve and maintain good correction of scoliotic deformities and have a low rate of pseudoarthrosis and instrument failure. Ideal sagittal parameters are maintained up to 10 years of follow-up. LEVEL OF EVIDENCE: 3.

Prospective cohort study. To compare the long-term, radiographic coronal and sagittal outcomes of these two approaches at 10-year follow-up. Both anterior and posterior instrumented fusions have been found to be safe and effective treatments for Lenke 5 adolescent idiopathic scoliosis with up to 2 to 5 years of follow-up. Few studies follow patients beyond this duration. 36 patients who underwent anterior (n = 25) or posterior instrumented spinal fusion (n = 11) for Lenke 5 adolescent idiopathic scoliosis over a 4-year period were recruited and followed for 10 years. Preoperative clinical data include patient's age and age of menarche. Operative data included instrumented levels, duration of surgery, and surgical blood loss. Postoperative data included duration of hospital stay, duration of intensive care unit stay, and complications. Pre- and postoperative radiographic data collected include coronal Cobb angles for structural thoracolumbar/lumbar curves, and sagittal angles­sagittal vertical axis, thoracic kyphosis, global lumbar angle, pelvic incidence, pelvic tilt, sacral slope, and upper and lower end vertebrae. Posterior surgery had a shorter operative time (P < 0.010) and hospital stay (P < 0.010). Coronal plane deformity improved by a mean of 74% in the anterior group and 71% in the posterior group. There was no significant change at 10 years in both groups (anterior P = 0.455 and posterior P = 0.325). Sagittal parameters remained unchanged. There was a higher incidence of proximal junctional kyphosis in the posterior (45%) compared to the anterior (16%) group (P < 0.010). Both anterior and posterior instrumentation and fusion are successful surgeries after 10 years of follow-up. They are comparable with regards to their ability to achieve and maintain good correction of scoliotic deformities and have a low rate of pseudoarthrosis and instrument failure. Ideal sagittal parameters are maintained up to 10 years of follow-up. Level of Evidence: 3.

Radiologically defining horizontal gaze using EOS imaging-a prospective study of healthy subjects and a retrospective audit.

BACKGROUND CONTEXT: As sagittal alignment of the cervical spine is important for maintaining horizontal gaze, it is important to determine the former for surgical correction. However, horizontal gaze remains poorly-defined from a radiological point of view. PURPOSE: The objective of this study was to establish radiological criteria to define horizontal gaze. STUDY DESIGN/SETTING: This study was conducted at a tertiary health-care institution over a 1-month period. PATIENT SAMPLE: A prospective cohort of healthy patients was used to determine the best radiological criteria for defining horizontal gaze. A retrospective cohort of patients without rigid spinal deformities was used to audit the incidence of horizontal gaze. OUTCOME MEASURES: Two categories of radiological parameters for determining horizontal gaze were tested: (1) the vertical offset distances of key identifiable structures from the horizontal gaze axis and (2) imaginary lines convergent with the horizontal gaze axis. MATERIALS AND METHODS: Sixty-seven healthy subjects underwent whole-body EOS radiographs taken in a directed standing posture. Horizontal gaze was radiologically defined using each parameter, as represented by their means, 95% confidence intervals (CIs), and associated 2 standard deviations (SDs). Subsequently, applying the radiological criteria, we conducted a retrospective audit of such radiographs (before the implementation of a strict radioimaging standardization). RESULTS: The mean age of our prospective cohort was 46.8 years, whereas that of our retrospective cohort was 37.2 years. Gender was evenly distributed across both cohorts. The four parameters with the lowest 95% CI and 2 SD were the distance offsets of the midpoint of the hard palate (A) and the base of the sella turcica (B), the horizontal convergents formed by the tangential line to the hard palate (C), and the line joining the center of the orbital orifice with the internal occipital protuberance (D). In the prospective cohort, good sensitivity (>98%) was attained when two or more parameters were used. Audit using Criterion B+D yielded compliance rates of 76.7%, a figure much closer to that of A+B+C+D (74.8%). From a practical viewpoint, Criterion B+D were most suitable for clinical use and could be simplified to the "3-6-12 rule" as a form of cursory assessment. Verbal instructions in the absence of stringent postural checks only ensured that ~75% of subjects achieved horizontal gaze. CONCLUSIONS: Fulfillment of Criterion B+D is sufficient to evaluate for horizontal gaze. Further criteria can be added to increase sensitivity. Verbal instructions alone yield high rates of inaccuracy when attempting to image patients in horizontal gaze. Apart from improving methods for obtaining radiographs, a radiological definition of horizontal gaze should be routinely applied for better evaluation of sagittal spinal alignment.

Bone bridge formation across the neuroforamen 14 years after instrumented fusion for isthmic spondylolisthesis-a case report.

This case report describes the first case of a bone bridge formation across the left L5/S1 neuroforamen after instrumented posterolateral fusion for L5/S1 isthmic spondylolisthesis. Our patient was a 70-year-old lady who had grade 2, L5/S1 isthmic spondylolisthesis and bilateral S1 nerve root compression. She suffered from mechanical low back pain and neurogenic claudication, with radicular pain over both S1 dermatomes. She underwent in-situ, instrumented, posterolateral fusion and was asymptomatic for more than 13 years before developing progressive onset of left radicular pain over the L5 dermatome. Imaging revealed a bisected left L5/S1 neuroforamen secondary to a bone bridge formation resulting in stenosis. The pars defect in this case may have had sufficient osteogenic and osteoinductive factors to heal following spinal stabilization. Although in-situ posterolateral fusion is an accepted surgical treatment for isthmic spondylolisthesis, surgeons should consider reduction of the spondylolisthesis and excision of the pars defects to avoid this possible long-term complication.

Delayed lymphocele formation following lateral lumbar interbody fusion of the spine.

PURPOSE: This paper aims to describe the rare post-operative complication of a lymphocele formation after lateral lumbar interbody fusion. METHODS: The patient in this case was a 76-year-old lady with a 10 year history of low back pain and neurogenic claudication. She had previously underwent multiple spine surgeries for her condition. She presented to our institution for a recurrence of her low back pain and right anterior thigh pain. She then underwent surgery in two stages; first, a mini-open lateral interbody fusion at L3/4 and L4/5; second, posterior instrumentation of T3 to S1 with sagittal spinal deformity correction. RESULTS: The patient recovered uneventfully in the initial post op period and was discharged within 8 days. However, she developed abdominal distension and discomfort 6 months after surgery. MRI and CT scan of her abdomen showed a retroperitoneal fluid collection compressing her left ureter, resulting in hydroureter and hydronephrosis. She was managed with a CT-guided drainage of the fluid collection. Fluid analysis was consistent with a lymphocele. Since the procedure, the patient has been asymptomatic for 2 years. CONCLUSIONS: Delayed lymphocele formation is a potential complication of lateral lumbar interbody fusion. When present, it can be managed conservatively with good results. This case suggests that surgeons should have a low threshold to investigate for a lymphocele development post-anterior or lateral lumbar spine surgery. The authors recommend the placement of a post surgical retroperitoneal drain, as it might assist in the early detection of a lymphocele formation.

Slump sitting X-ray of the lumbar spine is superior to the conventional flexion view in assessing lumbar spine instability.

BACKGROUND CONTEXT: Flexion radiographs have been used to identify cases of spinal instability. However, current methods are not standardized and are not sufficiently sensitive or specific to identify instability. PURPOSE: This study aimed to introduce a new slump sitting method for performing lumbar spine flexion radiographs and comparison of the angular range of motions (ROMs) and displacements between the conventional method and this new method. STUDY DESIGN: This study used is a prospective study on radiological evaluation of the lumbar spine flexion ROMs and displacements using dynamic radiographs. PATIENT SAMPLE: Sixty patients were recruited from a single spine tertiary center. OUTCOME MEASURE: Angular and displacement measurements of lumbar spine flexion were carried out. METHOD: Participants were randomly allocated into two groups: those who did the new method first, followed by the conventional method versus those who did the conventional method first, followed by the new method. A comparison of the angular and displacement measurements of lumbar spine flexion between the conventional method and the new method was performed and tested for superiority and non-inferiority. RESULTS: The measurements of global lumbar angular ROM were, on average, 17.3° larger (p<.0001) using the new slump sitting method compared with the conventional method. They were most significant at the levels of L3-L4, L4-L5, and L5-S1 (p<.0001, p<.0001 and p=.001, respectively). There was no significant difference between both methods when measuring lumbar displacements (p=.814). CONCLUSION: The new method of slump sitting dynamic radiograph was shown to be superior to the conventional method in measuring the angular ROM and non-inferior to the conventional method in the measurement of displacement.

Interpretation of hip fracture patterns using areal bone mineral density in the proximal femur.

INTRODUCTION: Bone mineral density scans are currently interpreted based on an average score of the entire proximal femur. Improvements in technology now allow us to measure bone density in specific regions of the proximal femur. The study attempts to explain the pathophysiology of neck of femur (NOF) and intertrochanteric/basi-cervical (IT) fractures by correlating areal BMD (aBMD) scores with fracture patterns, and explore possible predictors for these fracture patterns. MATERIALS AND METHODS: This is a single institution retrospective study on all patients who underwent hip surgeries from June 2010 to August 2012. A total of 106 patients (44 IT/basi-cervical, 62 NOF fractures) were studied. The data retrieved include patient characteristics and aBMD scores measured at different regions of the contralateral hip within 1 month of the injury. Demographic and clinical characteristic differences between IT and NOF fractures were analyzed using Fisher's Exact test and two-sample t test. Relationship between aBMD scores and fracture patterns was assessed using multivariable regression modeling. RESULTS: After adjusted multivariable analysis, T-Troc and T-inter scores were significantly lower in intertrochanteric/basi-cervical fractures compared to neck of femur fractures (P = 0.022 and P = 0.026, respectively). Both intertrochanteric/basi-cervical fractures (mean T.Tot -1.99) and neck of femur fractures (mean T.Tot -1.64) were not found to be associated with a mean T.tot less than -2.5. However, the mean aBMD scores were consistently less than -2.5 for both intertrochanteric/basi-cervical fractures and neck of femur fractures. Gender and calcium intake at the time of injury were associated with specific hip fracture patterns (P = 0.002 and P = 0.011, respectively). CONCLUSIONS: Hip fracture patterns following low energy trauma may be influenced by the pattern of reduced bone density in different areas of the hip. Intertrochanteric/basi-cervical fractures were associated with significantly lower T-Troc and T-Inter scores compared to neck of femur fractures, suggesting that the fracture traversed through the areas with the lowest bone density in the proximal femur. In the absence of reduced T.Troc and T.Inter, neck of femur fractures occurred more commonly. T-Total scores may underestimate the severity of osteoporosis/osteopenia and measuring T-score at the neck of femur may better reflect the severity of osteoporosis and likelihood of a fragility fracture.