Abstract. Objectives. A damaged vertebral body can exhibit accelerated ‘creep’ under constant load, leading to progressive vertebral deformity. However, the risk of this happening is not easy to predict in clinical practice. The present cadaveric study aimed to identify morphometric measurements in a damaged vertebral body that can predict a susceptibility to accelerated creep. Methods. Mechanical testing of 28 human spinal motion segments (three vertebrae and intervening soft tissues) showed how the rate of creep of a damaged vertebral body increases with increasing “damage intensity” in its trabecular bone. Damage intensity was calculated from vertebral body residual strain following initial compressive overload. The calculations used additional data from 27 small samples of vertebral trabecular bone, which examined the relationship between trabecular bone damage intensity and residual strain. Results. Calculations from trabecular bone samples showed a strong non-linear relationship between residual strain and trabecular bone damage intensity (R. 2. = 0.78, P < 0.001). In damaged vertebral bodies, damage intensity as calculated from residual strain was then related to vertebral creep rate (R. 2. = 0.39, P = 0.001). This procedure enabled accelerated vertebral body creep to be predicted from morphological changes (residual strains) in the damaged vertebral body. Conclusion. These findings suggest that morphometric measurements obtained from fractured vertebrae can be used to quantify vertebral damage intensity and hence to predict progressive vertebral deformity

Aims

The morphometry of the distal femur was largely studied to improve bone-implant fit in total knee arthroplasty (TKA), but little is known about the asymmetry of the posterior condyles. This study aimed to investigate the dimensions of the posterior condyles and the influence of externally rotating the femoral component on potential prosthetic overhang or under-coverage.

Background. The knee joint morphology varies according to gender and morphotype of the patients. Objectives. To measure the dimensions of the proximal tibia and distal femur of osteoarthritic knees in a group of patients from the same ethnic group (Arabs) and to compare these measurements with the dimensions of six total knee implants. Patients and methods. Three-dimensional CT reconstructions were used to collect morphologic data from 124 osteoarthritic knees. Anteroposterior and mediolateral measurements were obtained from tibial and femoral bony resection surfaces planned for patient-specific instrumentation (Figures 1 and 2). These measurements were compared to the dimensions for six different types of knee implants. Results. The average tibial mediolateral (tML) and tibial anteroposterior (tAP) measurement for the study group were 74.36±6 mm and 48.94±4.57 mm, respectively; the medial tibial plateau was larger than lateral. The average femur mediolateral (fML) and femur anteroposterior (fAP) measurements for the same group were 72.04±6.6 and 68.1±7.75, respectively. For implant matching, the average tibial aspect ratio was 152.62±12.66 and the femoral average aspect ratio was 106.37±14.34. Differences were found between morphometric measurements of males and females with significantly higher parameters for males when compared to female when compared in AP and mediolateral dimensions. Also, 22.5% of the operated knees had mismatch within 2 size of the same implant. Conclusion. There is significant asymmetry of proximal tibial plateau and femur condyles. Our data suggest mismatch between osteoarthritic Arabian knees and implant designs. These ethnic differences should be considered when designing knee implants

Background:. Currently, there are a variety of different reverse shoulder implant designs but few anatomic studies to support the optimal selection of prosthetic size. This study analyzed the glenohumeral relationships of patients who underwent reverse shoulder arthroplasty (RSA). Methods:. Ninety-two shoulders of patients undergoing primary RSA for a massive rotator cuff tear without bony deformity or deficiency and 10 shoulders of healthy volunteers (controls) were evaluated using three-dimensional CT reconstructions and computer aided design (CAD) software. Anatomic landmarks were used to define scapular and humeral planes in addition to articular centers. After aligning the humeral center of rotation with the glenoid center, multiple glenohumeral relationships were measured and evaluated for linearity and size stratification. The correction required to transform the shoulder from its existing state (CT scan) to a realigned image (CAD model) was compared between the RSA and control groups. Size stratification was verified for statistical significance between groups. Generalized linear modeling was used to investigate if glenoid height, coronal humeral head diameter and gender were predictive of greater tuberosity positions. Results:. All 92 shoulders were grouped into three different categories based on glenoid height. The humeral head size, glenoid size, lateral offset, and inferior offset all increased linearly (r. 2. > 0.95), but the rate of increase varied (slopes range from 0.59 to 1.9). Translations required to normalize the shoulder joint were similar between healthy and pathologic cases except for superior migration. Glenoid height, coronal humeral head diameter and gender predicted the greater tuberosity position within 1.09 ± 0.84 mm of actual position in ninety percent of the patient population. Morphometric measurements for each stratified group were all found to be statistically significant between groups (p ≥ 0.05). Conclusion:. Patients who undergo RSA with minimal bony deformity have superior subluxation of the glenohumeral joint. Predicting the anatomic position of the greater tuberosity is dependent on gender, glenoid height and coronal humeral head diameter. This anatomic data provides a guide to avoid inadvertent mismatch of prosthetic and patient shoulder size. If the surgeon is able to measure glenoid height and coronal humeral head diameter preoperatively, accurate planning of the position of the greater tuberosity can be accomplished

Ventral screw osteosynthesis is a common surgical method for treating fractures of the odontoid peg, but there is still no consensus about the number and diameter of the screws to be used. The purpose of this study was to develop a more accurate measurement technique for the morphometry of the odontoid peg (dens axis) and to provide a recommendation for ventral screw osteosynthesis.

Images of the cervical spine of 44 Caucasian patients, taken with a 64-line CT scanner, were evaluated using the measuring software MIMICS. All measurements were performed by two independent observers. Intraclass correlation coefficients were used to measure inter-rater variability.

The mean length of the odontoid peg was 39.76 mm (sd 2.68). The mean screw entry angle α was 59.45° (sd 3.45). The mean angle between the screw and the ventral border of C2 was 13.18° (sd 2.70), the maximum possible mean converging angle of two screws was 20.35° (sd 3.24). The measurements were obtained at the level of 66% of the total odontoid peg length and showed mean values of 8.36 mm (sd 0.84) for the inner diameter in the sagittal plane and 7.35 mm (sd 0.97) in the coronal plane. The mean outer diameter of the odontoid peg was 12.88 mm (sd 0.91) in the sagittal plane and 11.77 mm (sd 1.09) in the coronal plane. The results measured at the level of 90% of the total odontoid peg length were a mean of 6.12 mm (sd 1.14) for the sagittal inner diameter and 5.50 mm (sd 1.05) for the coronal inner diameter. The mean outer diameter of the odontoid peg was 11.10 mm (sd 1.0) in the sagittal plane and 10.00 mm (sd 1.07) in the coronal plane. In order to calculate the necessary screw length using 3.5 mm cannulated screws, 1.5 mm should be added to the measured odontoid peg length when anatomical reduction seems possible.

The cross-section of the odontoid peg is not circular but slightly elliptical, with a 10% greater diameter in the sagittal plane. In the majority of cases (70.5%) the odontoid peg offers enough room for two 3.5 mm cannulated cortical screws.

Cite this article: Bone Joint J 2013;95-B:536–42.

Quantitative knowledge on the anatomy of the medial collateral ligament (MCL) is important for preventing MCL damage during unicompartmental knee arthroplasty (UKA). The objective of this study was to quantitatively determine the morphology of the medial capsule and deep MCL on tibias. METHODS. 24 cadaveric human knees (control: 19, OA: 5) were dissected to investigate the deep MCL and capsule anatomy. The specimens were fixed in full extension and this position was maintained during the dissection and morphometric measurements. The distance from the tibial insertion sites of the medial capsule including deep MCL to the medial joint surface were measured at anterior, middle, and posterior sites. Posterior capsule slope and posterior tibia slope to the anterior tibia cortex was also measured. RESULTS. In control, the distance from the tibia insertion sites of the medial capsule including deep MCL to the anterior 1/3, middle 1/3, and posterior 1/3 of medial joint surface were 12.5 ± 1.5 mm and 8.0 ± 1.6 mm and 9.4 ± 1.6 mm, respectively. Posterior capsule slope and posterior tibia slope to the anterior tibia cortex were 6.3 ± 3.3 degree and 12.7 ± 2.1 degree, respectively. In OA, the distance from the tibia insertion sites of the medial capsule including deep MCL to the anterior 1/3, middle 1/3, and posterior 1/3 of medial joint surface were 14.0 ± 1.7 mm and 9.6 ± 1.9 mm and 10.8 ± 1.5 mm, respectively. Posterior capsule slope and posterior tibia slope to the anterior tibia cortex were 8.0 ± 3.5 degree and 14.5 ± 2.2 degree, respectively. CONCLUSIONS. The morphologic data on the medial capsule and deep MCL may provide useful information for preventing MCL damage during UKA surgical procedure

Bone shape estimation from partial observations, such as fluoroscopy or ultrasound, has been subject of significant interest over the past decade and can be regarded as the driving force behind several advances in statistical modelling of shape. While statistical models were initially used mostly as regularisers constraining shape matching algorithms, they are now increasingly employed due to their predictive ability, when only limited observations are available. With the current efforts toward minimal invasiveness, radiation exposure reduction, and optimization of the cost-effectiveness of procedures, two major challenges emerge on the field of statistical modelling. The first one is to develop methods that enable the use of as much information as possible that can be relevant for a specific shape prediction task, within the aforementioned limits. The second challenge concerns the accuracy of the resulting predictions, which needs to be quantified in order to evaluate the associated risks, and to optimise the data acquisition procedures. In terms of shape prediction, most studies so far have concentrated on individualizing statistical atlases based on imaging data. However, relevant information about skeletal morphology can also be obtained from simple anthropometric and morphometric measurements such as gender, age, body-mass index, and bone specific measurements. We develop a multivariate regression framework that enables to take into account such combinations of predictors simultaneously with sparse observations of the bone surface for improved prediction of the complete bone shape. In particular, we describe in a quantitative and localised fashion the individual contributions but also the complementarities of the heterogeneous sources of information with respect to bone morphology assessment. To do so, we compare the prediction errors obtained with different combinations of predictors, relying on cross-validation experiments. In addition to providing valuable and complementary predictive information, non-imaging measurements can be exploited to automatically initialise surface registration algorithms which increase their robustness for the determination of patient specific morphologies. A statistical model, by essence, is a mathematical model resulting from a learning phase using a set of training data. Statistical model based prediction is affected by three main sources of errors. The pre-processing of the training data, in particular the establishment of anatomical correspondences between the different samples, and the limited number of training elements constitute a first source of uncertainties. Second, the predictors can be affected by measurement noise, which will then propagate through the prediction process. Finally, and this is particularly important in the context of sparse observation data, the limited correlations between the predictors and the shape to predict imply theoretical limits for the achievable accuracy of such approaches. We have developed a framework enabling to account for these various sources of uncertainty, and propagating them through the prediction pipeline to generate confidence regions around the predicted shape. It relies extensively on cross-validation experiments in order to quantify the limitations of the statistical model with respect to the representation of new shapes (generalization ability) and to their prediction from partial data. Furthermore, we demonstrate the reliability of the obtained regions, following the procedure initially proposed in. We evaluate our approaches on a database of 140 femur bones, age range: 23–83, mean 62.57, stdv 15; 46% males and 54% females, with known age, height and weight. Morphometric measurements such as bone length, inter-condyle distance or anteversion angle are considered, either as predictors, together with sparse point clouds around the femoral head and greater trochanter, or as a pose-independent quality-of-fit metric. Cross-validation experiments indicate that a higher accuracy can be reached when complementing surface-based predictors with relevant anthropometric and morphometric information, and that reliable confidence regions can be estimated

Rapid prototyping (RP), especially useful in surgical specialities involving critical three-dimensional relationships, has recently become cheaper to access both in terms of file processing and commercially available printing resources. One potential problem has been the accuracy of models generated. We performed computed tomography on a cadaveric human patella followed by data conversion using open source software through to selective-laser-sintering of a polyamide model, to allow comparative morphometric measurements (bone v. model) using vernier calipers. Statistical testing was with Student's t-test. No significant differences in the dimensional measurements could be demonstrated. These data provide us with optimism as to the accuracy of the technology, and the feasibility of using RP cheaply to generate appropriate models for operative rehearsal of intricate orthopaedic procedures

Introduction. Autonomic nerve system (ANS) regulates intercostal vascular nutrition (internal mammary artery), and its pathological status leads to developmental asymmetry of the trunk and rib cage, and consequently producing scoliotic deformity of the spine. The aim of this study is to investigate the possible causation of idiopathic scoliosis in development abnormalities of ANS. Methods. We evaluated samples taken from 12 patients with idiopathic scoliotic deformities and a control set of three patients without scoliotic deformity. We examined the samples of autonomic nerves taken from convexity and concavity of the scoliotic deformity during the patients' surgical correction by the transthoracic approach. We used the electronmicroscopic method to analyse samples, and the morphometric method for statistical evaluation. Results. Evaluation of the samples taken from scoliotic convexity and the control samples of non-scoliotic patients showed normal findings in autonomic nerve structures. We detected significant morphological changes in all scoliotic samples taken from concavity. These changes were mostly in myelin vaginas with abnormalities and compression of the axon fibre, massive lesion and separation of the myelin sheath, vacualisation of cytoplasma of the Schwann cells, and condensation of the cytoblast. By morphometric measurements we found 23·71% of myelinised nerve fibres (MNF), 12·21% of unmyelinised nerve fibres (UNF), and 5·0% of Schwann cells (SC) in samples taken from scoliotic convexity, and 29·9% of MNF, 19·9% of UNF, and 16·7% of SC in control non-scoliotic samples. We recorded 17·36% of MNF, 5·82% of UNF, and 5·27% of SC in samples taken from concavity. Conclusions. We noted abnormalities in structure of ANS in concave side of scoliotic curves, and statistically significant differences between both sides of scoliotic deformity (convexity and concavity). Furthermore, we recorded discrepancies between scoliotic samples and non-scoliotic control samples. The abnormalities, mostly in the myelinated fibres, might be originated by the primary genetic lesion and thus could affect the development of scoliosis. The abnormalities of ANS can produce changes in internal mammary artery, and consequently can lead to the abnormal blood supply of vertebrae as well as anterior wall chest. These abnormalities of ANS could lead to the scoliotic origin in growing spine

Rapid prototyping (RP), especially useful in surgical specialities involving critical three-dimensional relationships, has recently become cheaper to access both in terms of file processing and commercially available printing resources. One potential problem has been the accuracy of models generated. We performed computed tomography on a cadaveric human patella followed by data conversion using open source software through to selective-laser-sintering of a polyamide model, to allow comparative morphometric measurements (bone v. model) using vernier calipers. Statistical testing was with Student's t-test. No significant differences in the dimensional measurements could be demonstrated. These data provide us with optimism as to the accuracy of the technology, and the feasibility of using RP cheaply to generate appropriate models for operative rehearsal of intricate orthopaedic procedures

Technological advances and economic trends are shaping the future of orthopaedics, where a clinical solution encompasses all phases of surgery. Minimally invasive surgery (MIS) continues to become more popular and important in modern-day orthopaedics, but brings added complexity to the operating room. Computer assisted surgery (CAS) has the potential to provide greater reliability, repeatability, and control to orthopedic surgeries, although limitations in the technologies currently available for minimally invasive CAS procedures leave much to be desired. Despite new techniques and modern technologies, improvements are needed to achieve consistency of optimal patient outcomes in orthopaedic surgery. Healthcare markets are moving to emphasize the value of patient-specific intervention with reliable, custom solutions. We are developing a framework for orthopedic CAS which utilizes new technologies and a cohesive approach in providing a robust solution for the future of orthopaedics. Through the use of surgical preplanning, intra-operative guidance, and post-operative gait analysis, a full analysis and design cycle is used to ensure optimal patient outcome by focusing on the combination of the three surgical phases. In order to realize this comprehensive framework, a system-level design approach combined with cutting-edge technology is needed, catering to patient-specific anatomical reconstruction. In the pre-operative phase, X-ray images are used in the 3-D reconstruction of patient-specific models of the targeted anatomy. This is combined with automated morphometric measurements to provide automatic cutting plane alignment and a complete design suite for patient-specific implants. In the intraoperative phase, new wireless navigation technologies provide robust performance where optical and electromagnetic tracking systems fall short. MEMS capacitive sensor array technology provides accurate and real-time pressure sensing feedback for ligament balancing, and new software frameworks virtualize surgical protocols. Extensive gait analysis including X-ray fluoroscopy provides 3-D kinematic data in the post-operative phase to provide valuable feedback on implant performance for improved implant design

Purpose: The purpose of the study is to measure the resected surface of femur of the Korean patients during total knee arthroplasty surgery and to compare these measurements with the dimensions of femoral implants in current use. Materials and Methods: Morphometric data (7 parameters) were obtained in 500 cases of resected femur of the Korean patients who underwent total knee arthroplasties, and these data were compared with four current implants designs. Results: The range of medial-lateral width at the given implant varies widely. The anterior width of the resected femur at the condyle is smaller than the widths of the most implants, creating an overhang. The medial-lateral width of the condyle at the level of transepicondylar line is wider than most of the present implants. However the widths of the resected posterior condyles were narrower at anterior-posterior alignment, causing overhang at the posterior condyles. We felt this will cause anterior tensioning at flexion and reduce the ability to flex further. Conclusion: The shape of the femur in Korean knee is different from that of current TKR implants in use, which are based on the anthropometric data of Caucasians. Therefore new design, better suited to the morphometric measurements of Korean knee, is necessary. Though historically this mismatch of the implant was well tolerated, new design to better fit the measurement of Korean knee should be considered for functional enhancement such as range of motion, durability and function

Introduction: Hip simulator tests, analyses of retrieved components as well as radiostereometric measurements revealed that cups made of highly linked polyethylene show a much better wear performance than cups of conventional polyethylene. However, to the best of our knowledge, histomorphological studies of tissues from the surrounding of highly cross – linked polyethylene components have not been reported yet. The aim of this study was to examine such tissues for particles, released from highly cross – linked polyethylene cups and to compare the findings with those of conventional polyethylene. Material and methods: So far, periprosthetic tissues retrieved at revisions of 11 total hip endoprostheses with highly cross – linked polyethylene cups could be analysed. The revisions became necessary 3 to 50 months after implantation because of cup loosening (4), stem loosening (1), infection (3), periprosthetic fracture of the femur (1), multiple dislocations (1) and periarticular ossification (1). The findings were compared with those of 5 artificial joints (2 ABG, 2 Müller Cup older design, 1 Metalback pressfit) with conventional polyethylene cups and 54 to 231 months of function. 5 μm sections were made from the tissues and conventionally stained with HE and van Gieson. Morphometric measurements were done using objectives 10 and 40 of an Olympus microscope and the ‘Analysis’ program of Soft Ware Imaging GmbH. In the Durasul TM – cases, the total amount and the total area of particles were ascertained while in the cases used for comparison only random CX 40 samples could be measured because of the much higher content of particles. Results: The DurasulTM cases showed in contrast to the cases with conventional polyethylene cups, no distinct foreign body reaction. In four of the DurasulTM cases no particles could be detected at all and in the remaining seven particles could be found only in a few areas. Their number per section was between 6 and 1208, their total area per mm. 2. section ranged between 0,03 and 6,99 × 10 5.mm. 2. In the conventional polyethylene cases the number of particles per section was between 2832 and 71447, their total area per mm. 2. section ranged between 1,06 and 25,91 × 10 3mm. 2. ! The average size of the DurasulTM particles was clearly bigger than the size of the conventional Polyethylene. Discussion: The measurements in tissues of early revisions show that DurasulTM releases much less particles into the surrounding than PE and cause rather no foreign body reaction. Accordingly, the burden of the tissue with polyethylene debris is much lower while the particle size is bigger with DurasulTM than with PE

Eleven articulated scoliotic spines were examined radiographically and morphometrically. Measurement of the curve on anteroposterior radiographs of the specimens gave a mean Cobb angle of 70 degrees, though true anteroposterior radiographs of the deformity revealed a mean Cobb angle of 99 degrees (41% greater). Lateral radiographs gave the erroneous impression that there was a mean kyphosis of 41 degrees while true lateral projections revealed a mean apical lordosis of 14 degrees. Morphometric measurements confirmed the presence of a lordosis at bony level, the apical vertebral bodies being significantly taller anteriorly (P less than 0.02). There were significant correlations (P less than 0.01) between the true size of the lateral scoliosis, the amount of axial rotation and the size of the apical lordosis. This study illustrates the three-dimensional nature of the deformity in scoliosis and its property of changing in character and magnitude according to the plane of radiographic projection